Publications

Cetindamar, D, Lammers, T & Sick, N 2020, 'Digital technologies, competitiveness & policies: An integrative city-based policy roadmap for entrepreneurial ecosystems' in Managing Innovation in a Global and Digital World, Springer Fachmedien Wiesbaden, Cham, Switzerland, pp. 49-62.
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This paper offers a conceptual city-based policy roadmap for policy makers who are interested in managing their entrepreneurial ecosystems. The literature lacks specific policies bringing together both technological developments and entrepreneurial activities at city level, even though recent studies point out the role of policies for entrepreneurial ecosystems in order to build entrepreneurial economies. Given the wide opportunities arising from digital technologies for economic growth, policy makers need to identify feasible frameworks to support a digitally competitive entrepreneurial ecosystem. By combining the previous literature on entrepreneurship and digital technologies within a particular urban context, this paper describes a conceptual roadmap as a tool that might help policy makers to plan the future competitiveness of their cities.

Cetindamar, D, Lammers, T & Sick, N 2020, 'Understanding the Relationship Between Smart Cities and Entrepreneurial Ecosystems: The Case of Sydney' in Biloria, N (ed), Data-driven Multivalence in the Built Environment, Springer International Publishing, Switzerland, pp. 301-315.
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Smart city literature is overdrawn with discussions on public services such as transportation while there is a need to broaden the analysis to understand the very rich dynamics of cities. In this chapter, the goal is to focus on the rise of technology-based entrepreneurs in cities who are creating emerging digital technologies. Cities have been a popular unit of analysis for technological development and economic activities due to their high dependency on immediate local context factors. Nowadays, transformation of cities into “smart” have increased their role further – both for economic value and for technological growth. This paper aims to expand the smart city concept to an ecosystem approach where cities become hubs of digital technologies. By combining the previous literature on entrepreneurship and digital technologies within a particular urban context, this paper discusses how smart cities could be a solid base to build digital entrepreneurship ecosystems for sustainable, liveable and competitive cities. In particular, the paper provides a case study for Sydney by illustrating the interactions between smart cities and digital entrepreneurship ecosystems in practice. The chapter ends with a summary of findings and implications for both policy makers and digital entrepreneurs.

Ekechukwu, J & Lammers, T 2020, 'Digital Technology to Enhance Project Leadership Practice: The Case of Civil Construction' in Digital Transformation in Business and Society, Springer International Publishing, Switzerland, pp. 247-271.
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Digital transformation is fundamentally influencing all aspects of business and society. It can enable individuals and organizations to transcend from one way of working to another. In construction, emphasis is shifting from project management to project leadership, as professionals need assisting tools to not only aid in managing tasks and activities, but aid in leading people. As such, the adoption of digital technologies may hold the key in taking project leadership practice into the future. To date, there have been few attempts to explore the potential of digital technology as an aid for project leadership development and practice. This research therefore aims to investigate this potential in the context of the Australian civil construction industry. We review the existing body of knowledge on both industry-specific leadership demands and relevant digital technology capabilities to identify areas of improvement and to guide interviews with construction project managers. So far, literature has focused on endorsing particular leadership behaviors and/or styles, while ignoring the difficulties faced by professionals in practicing these behaviors. We find that project managers of civil contractors within Sydney understand the significance of leadership but are often overwhelmed by its complexity.

Gong, S, Oberst, S & Wang, X 2020, 'A Non-linear Model of Rubber Shear Springs Validated by Experiments' in Nonlinear Dynamics of Structures, Systems and Devices, Springer International Publishing, Switzerland, pp. 319-328.
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Vibrating flip-flow screens provide an effective solution for screening highly viscous or fine materials. However, yet, only linear theory has been applied to their design. Yet, to understand deficiencies and to improve performance an accurate model especially of the rubber shear springs equipped in screen frames is critical for its dynamics to predict e.g.frequency- and amplitude-dependent behaviour. In this paper, the amplitude dependency of the rubber shear spring is represented by employing a friction model in which parameters are fitted to an affine function rather constant values used for the classic Berg’s model; the fractional derivative model is used to describe its frequency dependency and compared to conventional dashpot and Maxwell models with its elasticity being represented by a nonlinear spring. The experimentally validated results indicate that the proposed model with a nonlinear spring, friction and fractional derivative model is able to more accurately describe the dynamic characteristics of a rubber shear spring compared with other models.

Gong, S, Oberst, S & Wang, X 2020, 'A Non-linear Model of Rubber Shear Springs Validated by Experiments' in Lacarbonara, W, Balachandran, B, Ma, J, Tenreiro Machado, JA & Stepan, G (eds), Nonlinear Dynamics of Structures, Systems and Devices Proceedings of the International Nonlinear Dynamics Conference (NODYCON 2019), |, Springer, pp. 319-328.
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Vibrating flip-flow screens provide an effective solution for screening highly viscous or fine materials. However, only linear theory has been applied to their design. Yet, to understand deficiencies and to improve performance an accurate model especially of the rubber shear springs equipped in screen frames is critical for its dynamics to predict, e.g. frequency- and amplitude-dependent behaviour. In this chapter, the amplitude dependency of the rubber shear spring is represented by employing a friction model in which parameters are fitted to an affine function rather constant values used for the classic Berg’s friction model; the fractional derivative model is used to describe its frequency dependency and compared to conventional dashpot and Maxwell models with its elasticity being represented by a non-linear spring. The experimentally validated results indicate that the proposed model with a non-linear spring, friction and fractional derivative model is able to more accurately describe the dynamic characteristics of a rubber shear spring compared with other models.

Ji, J & Luo, Q 2020, 'Fracture Mechanics‐Based Design and Analysis of Structural Adhesive Joints' in Mittal, KL & Panigrahi, SK (eds), Structural Adhesive Joints Design, Analysis, and Testing, Wiley, USA, pp. 159-204.
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This chapter presents fracture mechanics based analysis and design of adhesively bonded structures. Common configurations and stress analysis characteristics of structural adhesive joints are introduced. Stress analysis and energy release rate based on a shear-lag model are firstly presented to show the importance of using fracture mechanics based design for structural adhesive joints. Modelling of adhesive joints and analytical stress analysis formulations are then derived to calculate energy release rates based on adhesive stresses; approaches to determine energy release rates based on the singular stress field and the beam theory are discussed. Finite element analysis based virtual crack closure technique and cohesive zone models to simulate progressive failure in adhesive joints are reviewed. Measurement of fracture toughness is discussed and determination of fracture parameters using state-of-the-art digital image correlation is presented.

Lammers, T, Borkert, M & Sick, N 2020, 'Unternehmertum in der digitalen Stadt – Welche Rolle spielt die digitale Gründerszene für die Wettbewerbsfähigkeit von Smart Cities? [Entrepreneurship in the digital city - what role does the digital start-up scene play for the competitiveness of smart cities]' in Hoelzle, K, TIberius, V & Surrey, H (eds), Perspektiven des Entrepreneurships - Unternehmerische Konzepte zwischen Theorie und Praxis, Schäffer-Poeschel Verlag, Germany, pp. 461-468.
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The digital city of the future, the “Smart City”, is becoming a beacon of hope to meet the challenges of a growing world population. Cities have therefore initiated digitization strategies in order to use the potential of new technologies for themselves. In parallel A technology-driven start-up scene is emerging in cities around the world, which has to be established Companies can potentially compete. In this article we ask ourselves which criteria are used to measure the success of a digital city and to what extent the digital start-up scene is taken into account. An analysis of existing indices is carried out which are located in the context of the competitiveness of digital cities. The total of 352 evaluation criteria used cover 249 different evaluation aspects. About different Indices recurring criteria for the analysis of competitiveness were found mainly for the Features connectivity, education, transportation infrastructure, and business environment. Despite the apparently high relevance of economic aspects in the evaluation, the digital one The start-up scene as a sub-area has only rarely been considered. A direct mention of The start-up scene can only be found in two of the 26 indices examined. A specific analysis of tech start-ups is not carried out in any of the indices examined. Before the Background of the outstanding potential of digital technologies and thus of tech start-ups, This article therefore provides both argumentation and first steps, the digital start-up scene to determine the competitiveness of cities.

Ruppert, MG & Moheimani, SOR 2020, 'Dynamics and Control of Active Microcantilevers' in Encyclopedia of Systems and Control, Springer London, pp. 1-6.
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Schulte, L, Schmitt, J, Meierhofer, F & Deuse, J 2020, 'Optimizing Inspection Process Severity by Machine Learning Under Label Uncertainty' in Advances in Intelligent Systems and Computing, Springer International Publishing, Switzerland, pp. 3-9.
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The increasing competition forces manufacturing companies striving for Zero Defect Manufacturing to constantly improve their products and processes. This vision cannot be realized completely however, so cost-efficient inspection of quality is of high importance: While no defects should remain undetected, this always comes at the expense of pseudo defects. As this effect is common knowledge, the automatically generated inspection results have to be verified by human process experts. As this manual verification leads to tremendous inspection costs, reducing pseudo defects is a major business case nowadays. This paper presents an approach to reduce pseudo defects by applying Machine Learning (ML). A decision support system based on recorded inspection data and ML techniques has been developed to reduce manual verification efforts.

Abdo, P, Huynh, BP, Braytee, A & Taghipour, R 2020, 'An experimental investigation of the thermal effect due to discharging of phase change material in a room fitted with a windcatcher', Sustainable Cities and Society, vol. 61, pp. 102277-102277.
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© 2020 Elsevier Ltd This paper investigates experimentally the effect of the Phase Change Material (PCM) discharging process as a passive cooling technique on the performance of a two sided windcatcher fitted on an acrylic chamber with dimensions 1250 × 1000 × 750 mm3. Four different models with different locations of PCM are studied, and the results are compared with each other and with a fifth model with No PCM. PCM is integrated respectively at the walls of the chamber, its floor and ceiling and also within the windcatcher's inlet channel. Humidity, temperature and air velocity are monitored for each of the models studied. It is noted that with all the models containing PCM, the average humidity inside the chamber changed only slightly compared to the model with No PCM. The difference in humidity ranged between 0 and 3.88 % which indicates that the humidity variations are not significant. The model with the PCM located on the floor, ceiling and walls as well as in the windcatcher's inlet channel has shown the best performance, with a significant minimum reduction of average temperature in the chamber of about 2.75 °C (approximately 9.33 %) compared with the model with No PCM.

Abdo, P, Taghipour, R & Huynh, BP 2020, 'Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs', Journal of Thermal Science and Engineering Applications, vol. 12, no. 4, pp. 1-34.
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Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

Acharya, P, Nguyen, KD, La, HM, Liu, D & Chen, I-M 2020, 'Nonprehensile Manipulation: a Trajectory-Planning Perspective', IEEE/ASME Transactions on Mechatronics, vol. PP, no. 99, pp. 1-1.
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IEEE This paper discusses nonprehensile manipulation of an asymmetric object using a robotic manipulator from a motion planning point of view. Four different aspects of the problem will be analyzed: object stability, motion planning, manipulator control, and experimental validation. Specifically, via an analysis of marginal stability of an object resting on a moving tray, the work establishes the critical accelerations of the manipulator's end-effector, below which the object's stability is guaranteed. These critical accelerations guide the design of the end-effector's motion for successful nonprehensile manipulation of the object. In particular, we propose two methods to formulate polynomial asymmetric s-curve trajectories such that the end- effector completes its motion in minimum time. In one method, the trajectory is divided into segments whose time intervals are then computed via a recursive algorithm. In the other method, we formulate an optimization problem and design the minimum-time trajectory by balancing the trade-off between the travel time and actuator effort. A series of experiments with a robotic arm is designed to validate and compare these motion planning methods in the context of nonprehensile manipulation. In addition, the experimental results demonstrate the advantages of the asymmetric s-curve motion profiles over the traditional symmetric s-curves.

Al zahrani, S, Islam, MS & Saha, SC 2020, 'Heat transfer augmentation in retrofitted corrugated plate heat exchanger', International Journal of Heat and Mass Transfer, vol. 161, pp. 120226-120226.
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Al zahrani, S, Islam, MS, Xu, F & Saha, SC 2020, 'Thermal performance investigation in a novel corrugated plate heat exchanger', International Journal of Heat and Mass Transfer, vol. 148, pp. 119095-119095.
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© 2019 Compact heat exchangers have become an essential necessity for power production and multi other purposes on a daily basis. The corrugated plate heat exchangers (CPHEs) are well-known for their high thermal performance. This study proposes a unique CPHE with a simple modification that can boost its thermal performance significantly. The overall tests have been conducted on four CPHEs for two symmetric chevron angles (β) of 30°/30° and 60°/60° Two CPHEs belong to the newly CPHEs, and the other two belong to the well-known basic CPHE. Data are obtained for steady-state, single-phase (water-water), counter-current arrangements, and for Reynolds number (Re) ranges from 500 to 2500. Sophisticated mesh techniques have been adopted to develop the mesh for the plates and the fluids between the plates. An appropriate grid refinement test has been carried out for the accuracy of the numerical results. The results have been validated with benchmark experimental and numerical data. A realizable k−ε turbulence model with scalable wall treatment found to provide the most consistent and accurate prediction of the thermal performance of CPHE. The numerical results showed that the Nusselt number (Nu) and the effectiveness (ϵ) of the newly developed CPHEs are much higher than that of the basic one, which can be very useful when a heavy heat duty is required. The enhancement for Nu is up to 75% and for ϵ is up to 42%, and generally both exhibit a direct proportional relationship with Re. Based on the numerical result, a new correlation to predict Nu has been developed.

Alambeigi, P, Burry, J, Zhao, S & Cheng, E 2020, 'A study of human vocal effort in response to the architectural auditory environment', Architectural Science Review, vol. 63, no. 3-4, pp. 262-274.
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© 2020 Informa UK Limited, trading as Taylor & Francis Group. This paper examines human auditory interaction with an architectural design hypothesized to decrease users’ vocal effort and thus enhance their speech privacy. This detailed design increased sound scattering in semi-enclosed meeting rooms within open plan offices. To achieve desirable speech intelligibility, a live sound environment is strongly recommended for meeting rooms. The research explores the hypothesis that by adding early reflections to the direct sound energy with an integrated design, the speaker as a self-listener might benefit from perceiving their own voice with more clarity. This can cause adaptive changes to subconscious vocal effort and increase the corresponding speech privacy of the space. An architecture-driven talker-quality experiment in a natural situation has been conducted in two rounds and in two different acoustic environments with 20 participants. The results implied the importance of human visual and spatial perception of privacy over auditory interaction with the environment on decreasing vocal effort. Such factors could thus be considered within the architectural design process.

Alfouneh, M, Ji, J & Luo, Q 2020, 'Optimal design of multi-cellular cores for sandwich panels under harmonic excitation', Composite Structures, vol. 248, pp. 112507-112507.
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© 2020 Elsevier Ltd Sandwich panels with cellular cores are increasingly used in engineering due to their superb dynamic performance. In this type of structure, core design significantly affects its mechanical property. This article is to study optimal design of a multi-cellular core to minimize dynamic response of the sandwich panel under harmonic excitation by use of topology optimization. In this study, structural dynamic responses to harmonic excitation are discussed and formulations of the dynamic response in terms of strain and kinetic energy densities are derived. Topology optimization with multi-fractional volume constraint is conducted for multi-cellular core design to minimize the dynamic response of the sandwich panel under harmonic excitation. The optimization to minimize or maximize the dynamic responses are discussed in optimal core designs of sandwich panels. A multi-objective optimisation problem is also considered to optimally suppress harmonic vibrations with a range of several frequencies. Numerical examples are presented to validate the derived formulations and to optimally design multi-cellular cores for sandwich panels to achieve better dynamic performance.

Almotairy, SM, Boostani, AF, Hassani, M, Wei, D & Jiang, ZY 2020, 'Effect of hot isostatic pressing on the mechanical properties of aluminium metal matrix nanocomposites produced by dual speed ball milling', Journal of Materials Research and Technology, vol. 9, no. 2, pp. 1151-1161.
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© 2019 The Authors. In this study a suggested model for flake powder metallurgy were implemented and its mechanism was explained. The suggested model includes dual-speed ball milling (DSBM) to take the advantage of the low-speed and high-speed ball milling (LSBM and HSBM). The modelled process was utilised to uniformly disperse SiC nanoparticles into aluminium metal matrix to produce nanocomposites. The produced mixed powder was hot isostatically pressed. The effects of processing parameters such as stearic acid content, SiC volume content, ball milling speed and time on the microstructure and consequently tensile properties of the manufactured composites have been investigated experimentally to optimise the processing parameters bringing about the enhanced tensile properties of the fabricated composites. The results showed that the implementation of LSBM and HSBM processes can be considered as a unique strategy, i.e. the dual-speed ball milling (DSBM), for uniform dispersion of SiC nanoparticles associated with perfect bonding.

Arqam, M, Dao, DV, Jahangiri, A, Mitchell, M & Woodfield, P 2020, 'Real gas model for an electric swashplate refrigeration compressor', International Journal of Refrigeration, vol. 118, pp. 210-219.
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Arqam, M, Dao, DV, Jahangiri, A, Yan, H, Mitchell, M & Woodfield, PL 2020, 'Analytical model for a 10 cylinder swash plate electric compressor', ASHRAE Transactions, vol. 126, pp. 351-359.
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Recent advancements in the field of mobile air conditioning and refrigeration have witnessed an extensive use of the swash plate compressor due to its compact structure, continuous operation, small size, light weight and better thermal comfort inside the vehicle. The design of the swash plate compressor is complex so that it requires considerable contributions from different fields of engineering viz. engineering mechanics, heat transfer and fluid dynamics. An estimate of compressor performance through an analytical/ mathematical model at the early stages of design and development serves as a useful tool for the designer. The input power, refrigerant mass flow rate, compression ratio and volumetric efficiency are important parameters to characterise the compressor performance. This paper presents an analytical/mathematical model for a 10-cylinder swash plate compressor with the emphasis on predicting its performance in terms of shaft torque and mass flow rate for a given rpm. A kinematic model is developed to obtain the piston displacement as an explicit function of angle of rotation of the swash plate. The model of piston and swash plate dynamics is developed then by analysing the interactions between forces and moments. The compression process model is formulated to determine the temperature and pressure inside the cylinder during one revolution of the swash plate along with the total mass flow rate in and out of the compressor. A time-varying model for the compressor is developed by combining the above three sub-models. Some experimental validation comparing predicted and measured drive torque has been done to verify the analytical/ mathematical model The predicted torque is in close agreement with the measured value.

Blamires, SJ 2020, 'Biomechanical costs and benefits of sit-and-wait foraging traps', Israel Journal of Ecology and Evolution, vol. 66, no. 1-2, pp. 5-14.
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AbstractTraps are rarely used by animals, despite the plausible benefits of broadening the number and diversity of prey that sit-and-wait foragers might be able to capture. The most well-known trap building sit-and-wait foragers are among the invertebrates, i.e. antlions, wormlions, glow worms, caddisflies, and spiders. A plausible hypothesis for the paucity of trap building by other animals is that biomechanical limitations render them inefficient or ineffective at catching sufficient prey. Here I examined the literature to make a valued judgement about the validity of this hypothesis. It appears that antlion and wormlion pit traps cannot catch and retain the largest prey they might expect to encounter. Arachnacampa glowworm traps are functionally efficient, facilitated by the animal’s bioluminescence. Nevertheless they only function in very moist or humid conditions. Caddisfly traps rely on flowing water to be able to capture their prey. Spiders are exceptional in developing a wide range of prey trapping strategies, from webs with dry adhesives, to sticky orb webs, to modified orb webs, e.g. elongated “ladder” webs, to webs with additional structures, and web aggregations. Some spiders have even redesigned their webs to minimize the high prey escape rates associated with web two dimensionality. These webs nevertheless are constructed and used at specific costs. While hard data across all of the invertebrate predators is lacking, there seems to be credence in the hypothesis that the biomechanical limitations placed on trap functionality can explain their limited use among animals.

Blamires, SJ, Little, DJ, White, TE & Kane, DM 2020, 'Photoreflectance/scattering measurements of spider silks informed by standard optics', Royal Society Open Science, vol. 7, no. 4, pp. 192174-192174.
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The silks of certain orb weaving spiders are emerging as high-quality optical materials. This motivates study of the optical properties of such silk and particularly the comparative optical properties of the silks of different species. Any differences in optical properties may impart biological advantage for a spider species and make the silks interesting for biomimetic prospecting as optical materials. A prior study of the reflectance of spider silks from 18 species reported results for three species of modern orb weaving spiders ( Nephila clavipes, Argiope argentata and Micrathena Schreibersi ) as having reduced reflectance in the UV range. (Modern in the context used here means more recently derived.) The reduced UV reflectance was interpreted as an adaptive advantage in making the silks less visible to insects. Herein, a standard, experimental technique for measuring the reflectance spectrum of diffuse surfaces, using commercially available equipment, has been applied to samples of the silks of four modern species of orb weaving spiders: Phonognatha graeffei , Eriophora transmarina , Nephila plumipes and Argiope keyserlingi . This is a different technique than used in the previous study. Three of the four silks measured have a reduced signal in the UV. By taking the form of the silks as optical elements into account, it is shown that this is attributable to a combination of wavelength-dependent absorption and scattering by the silks rather than differences in reflectance for the different silks. Phonognatha graeffei dragline silk emerges as a very interesting spider silk with a ...

Cetindamar, D, Lammers, T & Zhang, Y 2020, 'Exploring the knowledge spillovers of a technology in an entrepreneurial ecosystem—The case of artificial intelligence in Sydney', Thunderbird International Business Review, vol. 62, no. 5, pp. 457-474.
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AbstractNew knowledge presents opportunities for commercial value and can hence be a critical asset for entrepreneurial ecosystems (EEs). In particular, general purpose technologies are major drivers of entrepreneurship. Thus, a nuanced understanding on technological knowledge and its spillovers among actors within an EE is warranted. Using knowledge‐spillover‐based strategic entrepreneurship theory, we propose to observe knowledge spillovers through the assessment of the knowledge bases of a technology in an EE. To do so, this article proposes to use three key sources of knowledge: publications reflecting the emerging knowledge base, patents representing the realized knowledge base, and startups showing the experimental knowledge base. This article uses secondary data sources such as Web of Science and applies the method of bibliometrics to illustrate how an assessment is carried out in practice by evaluating the artificial intelligence (AI) knowledge bases in Sydney from 2000 to 2018. The findings are summarized with an illustration of the evolution of the key actors and their activities over time in order to indicate the key strengths and weaknesses in Sydney's AI knowledge among the different bases. Contrary to expectations from the high potential of knowledge spillovers from a general purpose digital technology such as AI, the article shows that apparent knowledge spillovers are yet highly limited in Sydney. Even though Sydney has a strong emerging knowledge base, the realized knowledge base seems weak and the experimental knowledge base is slowly improving. That observation itself verifies the need to take strategic actions to facilitate knowledge spillovers within EEs. After the implications for theory and policy makers are discussed, suggestions for further studies are proposed.

Chen, M, Ji, J, Liu, H & Yan, F 2020, 'Periodic Oscillations in the Quorum-Sensing System with Time Delay', International Journal of Bifurcation and Chaos, vol. 30, no. 09, pp. 2050127-2050127.
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The main aim of this paper is to study the oscillatory behaviors of gene expression networks in quorum-sensing system with time delay. The stability of the unique positive equilibrium and the existence of Hopf bifurcation are investigated by choosing the time delay as the bifurcation parameter and by applying the bifurcation theory. The explicit criteria determining the direction of Hopf bifurcation and the stability of bifurcating periodic solutions are developed based on the normal form theory and the center manifold theorem. Numerical simulations demonstrate good agreements with the theoretical results. Results of this paper indicate that the time delay plays a crucial role in the regulation of the dynamic behaviors of quorum-sensing system.

Chen, Y, Huang, S & Fitch, R 2020, 'Active SLAM for Mobile Robots With Area Coverage and Obstacle Avoidance', IEEE/ASME Transactions on Mechatronics, vol. 25, no. 3, pp. 1182-1192.
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© 1996-2012 IEEE. In this article, we present an active simultaneous localization and mapping (SLAM) framework for a mobile robot to obtain a collision-free trajectory with good performance in SLAM uncertainty reduction and in an area coverage task. Based on a model predictive control framework, these two tasks are solved by the introduction of a control switching mechanism. For SLAM uncertainty reduction, graph topology is used to approximate the original problem as a constrained nonlinear least squares problem. A convex half-space representation is applied to relax nonconvex spatial constraints that represent obstacle avoidance. Using convex relaxation, the problem is solved by a convex optimization method and a rounding procedure based on singular value decomposition. The area coverage task is addressed with a sequential quadratic programming method. A submap joining approach, called linear SLAM, is used to address the associated challenges of avoiding local minima, minimizing control switching, and potentially high computational cost. Finally, various simulations and experiments using an aerial robot are presented that verify the effectiveness of the proposed method, showing that our method produces a more accurate SLAM result and is more computationally efficient compared with multiple existing methods.

Chen, Y, Leighton, B, Zhu, H, Ke, X, Liu, S & Zhao, L 2020, 'Submap-Based Indoor Navigation System for the Fetch Robot', IEEE Access, vol. 8, pp. 81479-81491.
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Chen, Y, Zhao, L, Lee, KMB, Yoo, C, Huang, S & Fitch, R 2020, 'Broadcast Your Weaknesses: Cooperative Active Pose-Graph SLAM for Multiple Robots', IEEE Robotics and Automation Letters, vol. 5, no. 2, pp. 2200-2207.
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© 2016 IEEE. In this letter, we propose a low-cost, high-efficiency framework for cooperative active pose-graph simultaneous localization and mapping (SLAM) for multiple robots in three-dimensional (3D) environments based on graph topology. Based on the selection of weak connections in pose graphs, this method aims to find the best trajectories for optimal information exchange to repair these weaknesses opportunistically when robots move near them. Based on tree-connectivity, which is greatly related to the D-optimality metric of the Fisher information matrix (FIM), we explore the relationship between measurement (edge) selection and pose-measurement (node-edge) selection, which often occurs in active SLAM, in terms of information increment. The measurement selection problem is formulated as a submodular optimization problem and solved by an exhaustive method using rank-1 updates. We decide which robot takes the selected measurements through a bidding framework where each robot computes its predicted cost. Finally, based on a novel continuous trajectory optimization method, these additional measurements collected by the winning robot are sent to the requesting robot to strengthen its pose graph. In simulations and experiments, we validate our approach by comparing against existing methods. Further, we demonstrate online communication based on offline planning results using two unmanned aerial vehicles (UAVs).

Chen, Y, Zhao, L, Zhang, Y & Huang, S 2020, 'Dense Isometric Non-Rigid Shape-From-Motion Based on Graph Optimization and Edge Selection', IEEE Robotics and Automation Letters, vol. 5, no. 4, pp. 5889-5896.
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In this letter, we propose a novel framework for dense isometric non-rigid shape-from-motion (Iso-NRSfM) based on graph topology and edge selection. A weighted undirected graph, of which nodes, edges, and weighted values are respectively the images, the image warps, and the number of the common features, is built. An edge selection algorithm based on maximum spanning tree and sub-modular optimization is presented to pick out the well-connected sub-graph for the warps with multiple images. Using the infinitesimal planarity assumption, the Iso-NRSfM problem is formulated as a graph optimization problem with the virtual measurements, which are based on metric tensor and Christoffel Symbol, and the variables related to the derivatives of the constructed points along the surface. The solution of this graph optimization problem directly leads to the normal field of the shape. Then, using a separable iterative optimization method, we obtain the dense point cloud with texture corresponding to the deformable shape robustly. In the experiments, the proposed method outperforms existing work in terms of constructed accuracy, especially when there exists missing/appearing (changing) data, noisy data, and outliers.

Chiang, YK, Oberst, S, Melnikov, A, Quan, L, Marburg, S, Alù, A & Powell, DA 2020, 'Reconfigurable Acoustic Metagrating for High-Efficiency Anomalous Reflection', Physical Review Applied, vol. 13, no. 6, pp. 064067-064067.
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Recent study revealed that the scattering behaviors of bianisotropic scatterers can be controlled by an additional degree of freedom, represented as Willis coupling, which can be endowed with asymmetric wave scattering to form an acoustic metagrating for wavefront manipulation. Here, we introduce a flexible acoustic metagrating, formed by periodic arrays of properly design Willis scatterers, for anomalous reflection with nearly unitary efficiency and significantly less necessity of fine discretization. Numericalapproaches to predict the wave steering efficiency of the proposed acoustic metagratings with infinite and finite length are developed, which are utilized to demonstrate the strength and flexible features of the metagratings. Results reveal that the proposed acoustic metagrating can reroute incident wave into desired direction at a large angle with nearly unitary efficiency in reflection. The numerical predictions also show that the proposed designs offer a high efficient tunable platform in controlling the steering angles and operating frequencies. To practically realize the ability of extreme angle steering and tunable characteristics of the metagratings, designed structures are fabricated and examined experimentally. The acoustic wave is successfully rerouted to the targeted reflection angles by the finite metagrating. The flexibility regarding different steering angles and operating frequencies of the proposed metagratings are also demonstrated experimentally.

Craig, HC, Piorkowski, D, Nakagawa, S, Kasumovic, MM & Blamires, SJ 2020, 'Meta-analysis reveals materiomic relationships in major ampullate silk across the spider phylogeny', Journal of The Royal Society Interface, vol. 17, no. 170, pp. 20200471-20200471.
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Spider major ampullate (MA) silk, with its combination of strength and extensibility, outperforms any synthetic equivalents. There is thus much interest in understanding its underlying materiome. While the expression of the different silk proteins (spidroins) appears an integral component of silk performance, our understanding of the nature of the relationship between the spidroins, their constituent amino acids and MA silk mechanics is ambiguous. To provide clarity on these relationships across spider species, we performed a meta-analysis using phylogenetic comparative methods. These showed that glycine and proline, both of which are indicators of differential spidroin expression, had effects on MA silk mechanics across the phylogeny. We also found serine to correlate with silk mechanics, probably via its presence within the carboxyl and amino-terminal domains of the spidroins. From our analyses, we concluded that the spidroin expression shifts across the phylogeny from predominantly MaSp1 in the MA silks of ancestral spiders to predominantly MaSp2 in the more derived spiders' silks. This trend was accompanied by an enhanced ultimate strain and decreased Young's modulus in the silks. Our meta-analysis enabled us to decipher between real and apparent influences on MA silk properties, providing significant insights into spider silk and web coevolution and enhancing our capacity to create spider silk-like materials.

Dai, P, Lu, W, Le, K & Liu, D 2020, 'Sliding Mode Impedance Control for contact intervention of an I-AUV: Simulation and experimental validation', Ocean Engineering, vol. 196, pp. 106855-106855.
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© 2019 Elsevier Ltd Position/force control of an Intervention Autonomous Underwater Vehicle (I-AUV) is essential to many underwater intervention tasks (e.g., marine equipment maintenance, underwater welding and so on), and is challenging due to unknown fluid disturbances and model uncertainties. This paper applies the Sliding Mode Impedance Control (SMIC) to the full contact intervention of an I-AUV, from non-contact phase to contact phase. Both computational simulations and practical experiments are conducted to investigate the performance of SMIC. In simulations, considering model uncertainties and detailed fluid disturbances, accurate position and force tracking can be achieved, with the position tracking errors within ±3 × 10−3m and a Root Mean Square Error (RMSE) of 4 × 10−2N in tracking the desired contact force of 10N. For the purpose of experimental validation, the SMIC is implemented on an I-AUV developed in the University of Technology Sydney (UTS). The experimental results demonstrate the SMIC's good performance in the contact intervention of the I-AUV, with the position tracking errors within ±1.6×10−2 m and a RMSE of 0.97N in maintaining the desired contact force of 10N.

Dai, P, Lu, W, Le, K & Liu, D 2020, 'Sliding Mode Impedance Control for contact intervention of an I-AUV: Simulation and experimental validation', Ocean Engineering, vol. 196.

Deuse, J, Dombrowski, U, Nöhring, F, Mazarov, J & Dix, Y 2020, 'Systematic combination of Lean Management with digitalization to improve production systems on the example of Jidoka 4.0', International Journal of Engineering Business Management, vol. 12, pp. 184797902095135-184797902095135.
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Lean Management builds the basis for efficient production systems for many industrial companies. However, lots of potentials of Lean Management have been lifted and information and communication technologies in the context of digitalization and cyber-physical production systems (CPPS) offer new possibilities to enhance the performance of companies. Even though surveys indicate that companies recognize these potentials, especially small and medium-sized companies still face challenges in selection and implementation of suitable solutions. Thus, the research project GaProSys 4.0 aims at supporting companies with a systematic approach to combine existing structures of Lean Management with potentials of digitalization in development of a new set of methods to enhance production systems. This paper presents the approach of the research project to develop a structured set of methods and provides an example to illustrate the potentials.

Ding, R, Zhou, X, Zhang, R & Lu, W 2020, 'Retrieval, reporting and methodological characteristics forsystematic reviews/meta-analyses of animal models: a metaepidemiologicalstudy', Energy Engineering, vol. 117, no. 1, pp. 1-17.
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© 2020, Tech Science Press. All rights reserved. Free convection inside an attic enclosure in which sinusoidal heat flux applied on the inclined walls and a constant temperature applied on the base wall has been investigated numerically to demonstrate the primary flow characteristics and heat transfer within the attic enclosure over daily routine cycles. To solve the governing equations, the finite volume technique has been utilized. After performing the grid independency and time step size tests, the roles of Rayleigh number (Ra) and the attic aspect ratio (AR) on the unsteady flow structure and heat transfer phenomenon are explained for a constant Prandtl number (0.72) for the air. Results are illustrated as a form of stream function and isotherms. Moreover, heat transfer is calculated in terms of Nusselt number. The numerical simulations reveal stratified flow within the enclosure during the daytime nonlinear heating stage. However, during night-time, nonlinear cooling stage the flow turns into unstable as the forms of rising and sinking plumes for sufficiently higher Rayleigh number.

Ding, X, Wang, Y, Xiong, R, Li, D, Tang, L, Yin, H & Zhao, L 2020, 'Persistent Stereo Visual Localization on Cross-Modal Invariant Map', IEEE Transactions on Intelligent Transportation Systems, vol. 21, no. 11, pp. 4646-4658.
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Autonomous mobile vehicles are expected to perform persistent and accurate localization with low-cost equipment. To achieve this goal, we propose a stereo camera based visual localization method using a modified laser map, which takes the advantage of both the low cost of camera, and high geometric precision of laser data to achieve long-term performance. Considering that LiDAR and camera give measurements of the same environment in different modalities, the cross-modal invariance is investigated to modify the laser map for visual localization. Specifically, a map learning algorithm is introduced to sample the robust subsets in laser maps that are useful for visual localization using multi-session visual and laser data. Further, a generative map model is derived to describe this cross-modal invariance, based on which two types of measurements are defined to model the laser map points as appropriate visual observations. Tightly coupling these measurements within the local bundle adjustment during online sliding-window based visual odometry, the vehicle can achieve robust localization even one year after the map was built. The effectiveness of the proposed method is evaluated on both the public KITTI datasets and self-collected datasets in our campus, which include seasonal, illumination and object variations. On all experimental localization sessions, our method provides satisfactory results, even when the direction is opposite to that in the mapping session, verifying the superior performance of the laser map based visual localization method.

Geekiyanage, N, Sauret, E, Saha, S, Flower, R & Gu, Y 2020, 'Modelling of Red Blood Cell Morphological and Deformability Changes during In-Vitro Storage', Applied Sciences, vol. 10, no. 9, pp. 3209-3209.
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Storage lesion is a critical issue facing transfusion treatments, and it adversely affects the quality and viability of stored red blood cells (RBCs). RBC deformability is a key indicator of cell health. Deformability measurements of each RBC unit are a key challenge in transfusion medicine research and clinical haematology. In this paper, a numerical study, inspired from the previous research for RBC deformability and morphology predictions, is conducted for the first time, to investigate the deformability and morphology characteristics of RBCs undergoing storage lesion. This study investigates the evolution of the cell shape factor, elongation index and membrane spicule details, where applicable, of discocyte, echinocyte I, echinocyte II, echinocyte III and sphero-echinocyte morphologies during 42 days of in-vitro storage at 4 °C in saline-adenine-glucose-mannitol (SAGM). Computer simulations were performed to investigate the influence of storage lesion-induced membrane structural defects on cell deformability and its recoverability during optical tweezers stretching deformations. The predicted morphology and deformability indicate decreasing quality and viability of stored RBCs undergoing storage lesion. The loss of membrane structural integrity due to the storage lesion further degrades the cell deformability and recoverability during mechanical deformations. This numerical approach provides a potential framework to study the RBC deformation characteristics under varying pathophysiological conditions for better diagnostics and treatments.

Geekiyanage, NM, Sauret, E, Saha, SC, Flower, RL & Gu, YT 2020, 'Deformation behaviour of stomatocyte, discocyte and echinocyte red blood cell morphologies during optical tweezers stretching', Biomechanics and Modeling in Mechanobiology, vol. 19, no. 5, pp. 1827-1843.
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The red blood cell (RBC) deformability is a critical aspect, and assessing the cell deformation characteristics is essential for better diagnostics of healthy and deteriorating RBCs. There is a need to explore the connection between the cell deformation characteristics, cell morphology, disease states, storage lesion and cell shape-transformation conditions for better diagnostics and treatments. A numerical approach inspired from the previous research for RBC morphology predictions and for analysis of RBC deformations is proposed for the first time, to investigate the deformation characteristics of different RBC morphologies. The present study investigates the deformability characteristics of stomatocyte, discocyte and echinocyte morphologies during optical tweezers stretching and provides the opportunity to study the combined contribution of cytoskeletal spectrin network and the lipid-bilayer during RBC deformation. The proposed numerical approach predicts agreeable deformation characteristics of the healthy discocyte with the analogous experimental observations and is extended to further investigate the deformation characteristics of stomatocyte and echinocyte morphologies. In particular, the computer simulations are performed to investigate the influence of direct stretching forces on different equilibrium cell morphologies on cell spectrin link extensions and cell elongation index, along with a parametric analysis on membrane shear modulus, spectrin link extensibility, bending modulus and RBC membrane-bead contact diameter. The results agree with the experimentally observed stiffer nature of stomatocyte and echinocyte with respect to a healthy discocyte at experimentally determined membrane characteristics and suggest the preservation of relevant morphological characteristics, changes in spectrin link densities and the primary contribution of cytoskeletal spectrin network on deformation behaviour of stomatocyte, discocyte and echinocyte morphologies...

Ghosh, A, Islam, MS & Saha, SC 2020, 'Targeted Drug Delivery of Magnetic Nano-Particle in the Specific Lung Region', Computation, vol. 8, no. 1, pp. 10-10.
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Aerosolized drug inhalation plays an important role in the treatment of respiratory diseases. All of the published in silico, in vivo, and in vitro studies have improved the knowledge of aerosol delivery in the human respiratory system. However, aerosolized magnetic nano-particle (MNP) transport and deposition (TD) for the specific position of the human lung are still unavailable in the literature. Therefore, this study is aimed to provide an understanding of the magnetic nano-particle TD in the targeted region by imposing an external magnetic field for the development of future therapeutics. Uniform aerosolized nano-particle TD in the specific position of the lung airways will be modelled by adopting turbulence k–ω low Reynolds number simulation. The Euler–Lagrange (E–L) approach and the magneto hydrodynamics (MHD) model are incorporated in the ANSYS fluent (18.0) solver to investigate the targeted nano-particle TD. The human physical activity conditions of sleeping, resting, light activity and fast breathing are considered in this study. The aerosolized drug particles are navigated to the targeted position under the influence of external magnetic force (EMF), which is applied in two different positions of the two-generation lung airways. A numerical particle tracing model is also developed to predict the magnetic drug targeting behavior in the lung. The numerical results reveal that nano-particle deposition efficiency (DE) in two different magnetic field position is different for various physical activities, which could be helpful for targeted drug delivery to a specific region of the lung after extensive clinical trials. This process will also be cost-effective and will minimize unwanted side effects due to systemic drug distribution in the lung.

Gong, S, Oberst, S & Wang, X 2020, 'An experimentally validated rubber shear spring model for vibrating flip-flow screens', Mechanical Systems and Signal Processing, vol. 139, pp. 106619-106619.
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© 2020 Elsevier Ltd Vibrating flip-flow screens (VFFS) provide an effective solution for screening highly moist and fine-grained minerals, and the dynamic response of the main and the floating screen frames largely accounts for a VFFS's screening performance and its processing capacity. An accurate dynamic model of the rubber shear springs inserted between the frames of the VFFS is critical for its dynamic analysis but has rarely been studied in detail. In this paper, a variance-based global sensitivity analysis is applied to actually illustrate that the rubber shear spring is the most important component for the dynamics of VFFS. Then a nonlinear rubber shear spring model is proposed to predict its amplitude and frequency dependency, which is described by a friction model and a fractional derivative viscoelastic model, respectively, and the elasticity is predicted by a nonlinear spring. The reasonability of the proposed model is verified by experimental cyclic tests of the rubber shear spring. Comparisons between the newly proposed model and other classic models, including the Generalized Maxwell model, adopted for the dynamic analysis of the VFFS are carried out, and experimental tests of an industrial VFFS's dynamic response show that dynamics of the VFFS can be better described using the proposed model than the existing models. Furthermore, the method of the global sensitivity analysis is also applied to the newly VFFS dynamic model to calculate the sensitivities of model outputs caused by the input parameters. The results reveal that the dynamic response of an operating VFFS is most sensitive to changes in the stiffness of the rubber shear spring, followed by the mass of the floating screen frames.

Gong, Z, Singh, M & Wei, D 2020, 'An advanced technique for determining NC machining tool path to fabricate drawing die surface considering non-uniform thickness distribution in stamped blank', The International Journal of Advanced Manufacturing Technology, vol. 111, no. 5-6, pp. 1445-1455.
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© 2020, Springer-Verlag London Ltd., part of Springer Nature. Drawing process represents a significant area of production technology since it influences the feasibility of producing auto-body die panels. In the drawing process, the plastic deformation of blank is not uniform due to the intermittent deformation behavior of the material. This primes a non-uniform thickness distribution in the formed panels, which directly affects the die life and the quality of panels. In the presented study, a new algorithm was proposed for constructing the numerical control machining tool path for the new die surface obtained from FEM simulation and mesh mapping. The commercial package LS-DYNA was employed for the FEM simulation and to calculate the thickness distribution in the drawn workpiece. In order to construct the new numerical control machining tool path according to the new die surface, the positions of all cutter location points relative to the movement of new die mesh were determined. A set of forming die was machined using the proposed algorithm to fabricate a real workpiece of steel DC04. A comparison between the measured thicknesses in the fabricated workpiece and the FEM simulation results shows that they agree with each other very well, which directly validates the proposed algorithm. The developed method can improve product quality, increase production efficiency, and reduce labor intensity.

Guertler, MR, Kriz, A & Sick, N 2020, 'Encouraging and enabling action research in innovation management', R&D Management, vol. 50, no. 3, pp. 380-395.
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Although action research offers great advantages of connecting academia and practice, it is surprisingly underutilised in innovation management. This paper, therefore, focuses on how innovation management research and researchers can more effectively and efficiently apply action research to their domain. The analysis commences with the rationale for aligning action research and innovation management before assessing the strengths and limitations of existing interdisciplinary action research approaches from an innovation management perspective. Combining and enhancing the strengths of these approaches, a new Action Innovation Management Research (AIM‐R) framework is developed to assist in resolving the increasing demand for action‐orientation in innovation management. AIM‐R offers a structured research process for systematically applying action research as a way of encouraging rigorous research processes, while also importantly stimulating relevant practical outcomes. AIM‐R specifically considers different change levels (individual, team, organisational) and objects (e.g. outcome, process, capability) critical for the multi‐faceted character of innovation management. A real‐world example towards the end of the article illustrates how AIM‐R has been applied to a complex problem‐solution space. This example adds important insights for readers wanting to apply this more engaged, but currently underutilised, innovation management research technique.

Halkon, BJ & Rothberg, SJ 2020, 'Establishing correction solutions for Scanning Laser Doppler Vibrometer measurements affected by sensor head vibration', Mechanical Systems and Signal Processing, vol. 150.
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Scanning Laser Doppler Vibrometer (SLDV) measurements are affected by sensorhead vibrations as if they are vibrations of the target surface itself. Thispaper presents practical correction schemes to solve this important problem.The study begins with a theoretical analysis, for arbitrary vibration and anyscanning configuration, which shows that the only measurement required is ofthe vibration velocity at the incident point on the final steering mirror inthe direction of the outgoing laser beam and this underpins the two correctionoptions investigated. Correction sensor location is critical; the first schemeuses an accelerometer pair located on the SLDV front panel, either side of theemitted laser beam, while the second uses a single accelerometer located alongthe optical axis behind the final steering mirror. Initial experiments with avibrating sensor head and stationary target confirmed the sensitivity to sensorhead vibration together with the effectiveness of the correction schemes whichreduced overall error by 17 dB (accelerometer pair) and 27 dB (singleaccelerometer). In extensive further tests with both sensor head and targetvibration, conducted across a range of scan angles, the correction schemesreduced error by typically 14 dB (accelerometer pair) and 20 dB (singleaccelerometer). RMS phase error was also up to 30% lower for the singleaccelerometer option, confirming it as the preferred option. The theorysuggests a geometrical weighting of the correction measurements and thisprovides a small additional improvement. Since the direction of the outgoinglaser beam and its incident point on the final steering mirror both change asthe mirrors scan the laser beam, the use of fixed axis correction transducersmounted in fixed locations makes the correction imperfect. The associatederrors are estimated and expected to be generally small, and the theoreticalbasis...

Harcombe, DM, Ruppert, MG & Fleming, AJ 2020, 'A review of demodulation techniques for multifrequency atomic force microscopy', Beilstein Journal of Nanotechnology, vol. 11.
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This article compares the performance of traditional and recently proposed demodulators for multifrequency atomic force microscopy. The compared methods include the lock-in amplifier, coherent demodulator, Kalman filter, Lyapunov filter, and direct-design demodulator. Each method is implemented on a field-programmable gate array (FPGA) with a sampling rate of 1.5 MHz. The metrics for comparison include the sensitivity to other frequency components and the magnitude of demodulation artifacts for a range of demodulator bandwidths. Performance differences are demonstrated through higher harmonic atomic force microscopy imaging.

Hashem Zadeh, SM, Mehryan, SAM, Islam, MS & Ghalambaz, M 2020, 'Irreversibility analysis of thermally driven flow of a water-based suspension with dispersed nano-sized capsules of phase change material', International Journal of Heat and Mass Transfer, vol. 155, pp. 119796-119796.
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© 2020 A precise understanding of the thermal behaviour and entropy generation of a suspension comprising nano-encapsulated phase change materials (NEPCM) is important for the thermal energy storage and heat transfer enhancement in various engineering applications. Studies to date, have improved the knowledge of the heat transfer of NCPCM. However, a suspension comprising NEPCM in the porous medium could enhance the overall heat transfer performance. Therefore, this study aims to investigate the thermal, hydrodynamic and entropy generation behaviour of the NEPCM-suspensions in a porous medium. Conjugate natural convection heat transfer and entropy generation in a square cavity composed of a porous matrix (glass balls), occupied by a suspension comprising nano-encapsulated phase change materials, and two solid blocks is numerically investigated. Galerkin Finite Element Method is employed to solve the nonlinear coupled equations for the porous flow and heat transfer. The phase transition and the released/absorbed latent heat of the nano-capsules are attributed in a temperature-dependent heat capacity field. The thermal conductivity ratio (1 ≤ Rk ≤ 100), the Darcy number (10−5 ≤ Da ≤ 10−1), the Stefan number (0.2 ≤ Ste ≤ 1), the porosity of porous medium (0.2 ≤ ε ≤ 0.9), the dimensionless fusion temperature (0.05 ≤ Tfu ≤ 0.95), the solid walls thickness (ds = 0.1 and 0.3), and the volume fraction of the nano-capsules (0.0 ≤ φ ≤ 5%) are considered for the numerical calculations. The numerical results illustrate that the rates of heat transfer and the average Bejan number are maximum and the generated entropy is minimum when the fusion temperature of the nano-capsules is Tfu = 0.5. Besides, adding the nano-sized particles of encapsulated phase change materials to the host fluid increases the heat transfer rate up to 45% (for the studied set of parameters) and also augments the average Bejan number. The total entropy generation elevates with the increment of the volume...

Hassan, M & Liu, D 2020, 'PPCPP: A Predator–Prey-Based Approach to Adaptive Coverage Path Planning', IEEE Transactions on Robotics, vol. 36, no. 1, pp. 284-301.
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© 2004-2012 IEEE. Most of the existing coverage path planning (CPP) algorithms do not have the capability of enabling a robot to handle unexpected changes in the coverage area of interest. Examples of unexpected changes include the sudden introduction of stationary or dynamic obstacles in the environment and change in the reachable area for coverage (e.g., due to imperfect base localization by an industrial robot). Thus, a novel adaptive CPP approach is developed that is efficient to respond to changes in real-time while aiming to achieve complete coverage with minimal cost. As part of the approach, a total reward function that incorporates three rewards is designed where the first reward is inspired by the predator-prey relation, the second reward is related to continuing motion in a straight direction, and the third reward is related to covering the boundary. The total reward function acts as a heuristic to guide the robot at each step. For a given map of an environment, model parameters are first tuned offline to minimize the path length while assuming no obstacles. It is shown that applying these learned parameters during real-time adaptive planning in the presence of obstacles will still result in a coverage path with a length close to the optimized path length. Many case studies with various scenarios are presented to validate the approach and to perform numerous comparisons.

Hayati, H, Eager, D, Peham, C & Qi, Y 2020, 'Dynamic Behaviour of High Performance of Sand Surfaces Used in the Sports Industry', Vibration, vol. 3, no. 4, pp. 410-424.
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The sand surface is considered a critical injury and performance contributing factor in different sports, from beach volleyball to greyhound racing. However, there is still a significant gap in understanding the dynamic behaviour of sport sand surfaces, particularly their vibration behaviour under impact loads. The purpose of this research was to introduce different measurement techniques to the study of sports sand surface dynamic behaviour. This study utilised an experimental drop test, accelerometry, in-situ moisture content and firmness data, to investigate the possible correlation between the sand surface and injuries. The analysis is underpinned by data gathered from greyhound racing and discussed where relevant.

Hayati, H, Eager, D, Pendrill, A-M & Alberg, H 2020, 'Jerk within the Context of Science and Engineering—A Systematic Review', Vibration, vol. 3, no. 4, pp. 371-409.
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Rapid changes in forces and the resulting changes in acceleration, jerk and higher order derivatives can have undesired consequences beyond the effect of the forces themselves. Jerk can cause injuries in humans and racing animals and induce fatigue cracks in metals and other materials, which may ultimately lead to structure failures. This is a reason that it is used within standards for limits states. Examples of standards which use jerk include amusement rides and lifts. Despite its use in standards and many science and engineering applications, jerk is rarely discussed in university science and engineering textbooks and it remains a relatively unfamiliar concept even in engineering. This paper presents a literature review of the jerk and higher derivatives of displacement, from terminology and historical background to standards, measurements and current applications.

Hendryx, M, Islam, MS, Dong, G-H & Paul, G 2020, 'Air Pollution Emissions 2008–2018 from Australian Coal Mining: Implications for Public and Occupational Health', International Journal of Environmental Research and Public Health, vol. 17, no. 5, pp. 1570-1570.
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Occupational exposure limits for respirable coal dust are based on exposure during working hours, but coal miners may experience additional community-based exposures during nonworking hours. We analyzed Australia National Pollutant Inventory (NPI) data for the years 2008–2018 to estimate air pollutants (metals, nitrogen oxides, particulate matter ≤ 10 micrometers (PM10) and ≤2.5 micrometers (PM2.5)) originating from coal mines. PM10 levels from community-based air monitors in Queensland and New South Wales were also compared between mining and nonmining communities. Results indicated that tons of coal mined increased over the study period, and that levels of particulate matter, metals, and nitrogen oxides increased significantly over time as well. Coal mines accounted for 42.1% of national PM10 air emissions from NPI sites. PM2.5 from coal mines accounted for 19.5% of the national total, metals for 12.1%, and nitrogen oxides for 10.1%. Coal mining occurred in 57 different post codes; the 20 coal-mining post codes with the highest PM10 emissions were home to 160,037 people. Emissions of all studied pollutants were significantly higher from coal mining sites than from other types of NPI sites. Results from community-based air monitoring stations indicated significantly higher population PM10 exposure in coal mining communities than in nonmining communities. The health of the public at large is impacted by coal mining, but to the extent that miners also live near coal mining operations, their total exposure is underestimated by consideration of exposure only during working hours.

Hossain, MI, Eager, D & Walker, PD 2020, 'Greyhound racing ideal trajectory path generation for straight to bend based on jerk rate minimization', Scientific Reports, vol. 10, no. 1, p. 7088.
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AbstractThis paper presents methods for modelling and designing an ideal path trajectory between straight and bend track path segments for racing greyhounds. To do this, we numerically generate clothoid and algebraic curve segments for racing quadrupeds using a sequential vector transformation method as well as using a helper equation for approaching ideal clothoid segments that would respect greyhound kinematic parameters and boundary conditions of the track. Further, we look into the limitations of using a clothoid curve for racing dog track path design and propose a smooth composite curve for track transition design which roughly maintains G3 curvature continuity for smooth jerk to overcome limitations of a clothoid transition. Finally, we show results from race data modelling and past injury data, which provide a strong indication of clothoid curve segments improving the dynamics and safety of racing greyhounds while reducing injuries.

Hossain, SI, Gandhi, NS, Hughes, ZE & Saha, SC 2020, 'The role of SP-B_1–25 peptides in lung surfactant monolayers exposed to gold nanoparticles', Physical Chemistry Chemical Physics, vol. 22, no. 27, pp. 15231-15241.
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Lung surfactant monolayer’s (acts as the first line barrier for inhaled nanoparticles) components (lipids and peptides) rearrange themselves by the influence of exposed gold nanoparticles at various stages of the breathing cycle.

Hu, W, Huang, J, Zhang, X, Zhao, S, Pei, L, Li, H, Liu, Y & Wang, Z 2020, 'UV and thermal dual responsive coatings with high adhesion and mechanical robust properties', Progress in Organic Coatings, vol. 147, pp. 105771-105771.
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Hu, W, Huang, J, Zhang, X, Zhao, S, Pei, L, Zhang, C, Liu, Y & Wang, Z 2020, 'A mechanically robust and reversibly wettable benzoxazine/epoxy/mesoporous TiO2 coating for oil/water separation', Applied Surface Science, vol. 507, pp. 145168-145168.
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Huo, X, Liu, H, Luo, Q, Sun, G & Li, Q 2020, 'On low-velocity impact response of foam-core sandwich panels', International Journal of Mechanical Sciences, vol. 181, pp. 105681-105681.
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© 2020 Elsevier Ltd This study aimed to investigate low-velocity impact responses and crashworthiness of different aluminum foam-core sandwich structures. Several drop-weight dynamic impact tests were first conducted on both sandwich structures and their individual components to explore the mechanism of energy absorption and interactive effect between the foam core and facesheets. Different shapes and sizes of impactors were used in the experiments. The full-field deflection distribution was acquired by a 3D optical scanner to assess the failure patterns. A full-scale finite element model was then created to simulate the low-velocity impacting response of the foam-core sandwich panels. After the finite element model was validated against the experimental results, it was used to further explore the crash behavior of multi-layered sandwiches. It was found that multi-layer sandwich structure had much better performance in the crush force efficiency than those with single-layer foam core. Based upon the energy principle, an energy-based analytical model was also derived to estimate the initial peak load. It was demonstrated that the analytical predictions were in good agreement with the experimental and numerical results. The presented experimental, numerical and analytical studies are anticipated to provide systematic understanding and new knowledge for design of multilayer sandwich configurations aiming at more desirable impact resistance and better lightweight characteristics.

Islam, M, Saha, SC, Yarlagadda, PKDV & Karim, A 2020, 'A tool to minimize the need of Monte Carlo ray tracing code for 3D finite volume modelling of a standard parabolic trough collector receiver under a realistic solar flux profile', Energy Science & Engineering, vol. 8, no. 9, pp. 3087-3102.
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AbstractThe energy collection element of a parabolic trough collector includes a selective coated metallic receiver tube inside an evacuated glass tube. Perpendicularly incident sun light on the parabolic trough mirror aperture is concentrated on the receiver tube highly nonuniformly along its circular direction. This solar energy is collected as thermal energy circulating a suitable heat transfer fluid (HTF) through the tube. This conjugate heat transfer phenomenon under nonuniform heat flux boundary condition is computationally studied applying 3D finite volume (FV) modelling technique of computational fluid dynamics coupled with Monte Carlo ray tracing (MCRT) optical data. The MCRT model simulates the actual flux profile around the receiver tube. Apart from a FV model, this coupled study requires expertise in, and access to, a suitable MCRT code. A combination of polynomial correlations and user‐defined function (UDF) is introduced in this article in order to minimize the need of MCRT codes from subsequent FV modelling of the receiver tube of the Luz Solar 2 (LS2) collector. The correlations are developed from a verified 3D MCRT model, which is equivalent to the local irradiation data as a function of receiver circular location. The UDF includes two algorithms: one to develop solar flux profile from the correlations around the receiver, and the other to calculate heat loss from the receiver. Interpreting the UDF into ANSYS Fluent, a 3D FV model of the LS2 receiver is developed and validated with experimental results. The effectiveness of the UDF as an alternative to MCRT code is verified. The FV model is capable to investigate the heat transfer characteristics of the LS2 collector receiver at different solar irradiation level, optical properties of the collector components, glass tube conditions, HTFs, inserts or swirl generators, collector length, and internal diameter of the tube.

Islam, MS, Gu, Y, Farkas, A, Paul, G & Saha, SC 2020, 'Helium–Oxygen Mixture Model for Particle Transport in CT-Based Upper Airways', International Journal of Environmental Research and Public Health, vol. 17, no. 10, pp. 3574-3574.
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The knowledge of respiratory particle transport in the extra-thoracic pathways is essential for the estimation of lung health-risk and optimization of targeted drug delivery. The published literature reports that a significant fraction of the inhaled aerosol particles are deposited in the upper airways, and available inhalers can deliver only a small amount of drug particles to the deeper airways. To improve the targeted drug delivery efficiency to the lungs, it is important to reduce the drug particle deposition in the upper airways. This study aims to minimize the unwanted aerosol particle deposition in the upper airways by employing a gas mixture model for the aerosol particle transport within the upper airways. A helium–oxygen (heliox) mixture (80% helium and 20% oxygen) model is developed for the airflow and particle transport as the heliox mixture is less dense than air. The mouth–throat and upper airway geometry are extracted from CT-scan images. Finite volume based ANSYS Fluent (19.2) solver is used to simulate the airflow and particle transport in the upper airways. Tecplot software and MATLAB code are employed for the airflow and particle post-processing. The simulation results show that turbulence intensity for heliox breathing is lower than in the case of air-breathing. The less turbulent heliox breathing eventually reduces the deposition efficiency (DE) at the upper airways than the air-breathing. The present study, along with additional patient-specific investigation, could improve the understanding of particle transport in upper airways, which may also increase the efficiency of aerosol drug delivery.

Islam, MS, Paul, G, Ong, HX, Young, PM, Gu, YT & Saha, SC 2020, 'A Review of Respiratory Anatomical Development, Air Flow Characterization and Particle Deposition', International Journal of Environmental Research and Public Health, vol. 17, no. 2, pp. 380-380.
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The understanding of complex inhalation and transport processes of pollutant particles through the human respiratory system is important for investigations into dosimetry and respiratory health effects in various settings, such as environmental or occupational health. The studies over the last few decades for micro- and nanoparticle transport and deposition have advanced the understanding of drug-aerosol impacts in the mouth-throat and the upper airways. However, most of the Lagrangian and Eulerian studies have utilized the non-realistic symmetric anatomical model for airflow and particle deposition predictions. Recent improvements to visualization techniques using high-resolution computed tomography (CT) data and the resultant development of three dimensional (3-D) anatomical models support the realistic representation of lung geometry. Yet, the selection of different modelling approaches to analyze the transitional flow behavior and the use of different inlet and outlet conditions provide a dissimilar prediction of particle deposition in the human lung. Moreover, incorporation of relevant physical and appropriate boundary conditions are important factors to consider for the more accurate prediction of transitional flow and particle transport in human lung. This review critically appraises currently available literature on airflow and particle transport mechanism in the lungs, as well as numerical simulations with the aim to explore processes involved. Numerical studies found that both the Euler–Lagrange (E-L) and Euler–Euler methods do not influence nanoparticle (particle diameter ≤50 nm) deposition patterns at a flow rate ≤25 L/min. Furthermore, numerical studies demonstrated that turbulence dispersion does not significantly affect nanoparticle deposition patterns. This critical review aims to develop the field and increase the state-of-the-art in human lung modelling.

Kalhori, H, Alamdari, MM, Li, B, Halkon, B, Hosseini, SM, Ye, L & Li, Z 2020, 'Concurrent Identification of Impact Location and Force Magnitude on a Composite Panel', International Journal of Structural Stability and Dynamics, vol. 20, no. 10, pp. 2042004-2042004.
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Simultaneous estimation of both the location and force history of an impact applied on a lattice truss core sandwich panel is inversely carried out utilizing velocity signals collected by means of a scanning laser Doppler vibrometer. The algorithm assumes that several impact forces are exerted concurrently on a number of specified locations on a panel, provided that the magnitude of all impact forces but one is actually equal to zero. This condition equates to a scenario where an impact occurs at only one location. The purpose is therefore to detect the actual impact location among all potential locations, together with its force history, through minimizing error functions. Two algorithms, the one-to-one (even-determined) approach and the superposition approach, are considered. The one-to-one approach solves the reconstruction problem independently for each pair of impact and measurement points. However, in the superposition approach, the impact forces at all potential locations are concurrently reconstructed through a single matrix equation. It is shown that the one-to-one approach fails to detect the true impact location while the superposition approach recognizes the actual impact location based on some qualitative evaluating criteria. Adopting the superposition approach, for a problem with four possible impact locations, two scenarios one with four and one with 12 measurement points, are investigated. It is observed that the additional measurement points do not necessarily enhance the efficiency and accuracy of the proposed method. It is found that different arrangements of measuring points lead to identification of the location and the magnitude of the impact force, though the use of four evenly distributed measurement points seems to be most effective in simultaneous identification of the location and magnitude of the impact force. Further, a quantitative index based on the concept of similarity search for time-series using wavelet transf...

Karimi, M, Croaker, P, Maxit, L, Robin, O, Skvortsov, A, Marburg, S & Kessissoglou, N 2020, 'A hybrid numerical approach to predict the vibrational responses of panels excited by a turbulent boundary layer', Journal of Fluids and Structures, vol. 92, pp. 102814-102814.
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© 2019 Elsevier Ltd In this work, a hybrid numerical approach to predict the vibrational responses of planar structures excited by a turbulent boundary layer is presented. The approach combines an uncorrelated wall plane wave technique with the finite element method. The wall pressure field induced by a turbulent boundary layer is obtained as a set of uncorrelated wall pressure plane waves. The amplitude of these plane waves are determined from the cross spectrum density function of the wall pressure field given either by empirical models from literature or from experimental data. The response of the planar structure subject to a turbulent boundary layer excitation is then obtained from an ensemble average of the different realizations. The numerical technique is computationally efficient as it rapidly converges using a small number of realizations. To demonstrate the method, the vibrational responses of two panels with simply supported or clamped boundary conditions and excited by a turbulent flow are considered. In the case study comprising a plate with simply supported boundary conditions, an analytical solution is employed for verification of the method. For both cases studies, numerical results from the hybrid approach are compared with experimental data measured in two different anechoic wind tunnels.

Karimi, M, Maxit, L, Meyer, V, Marburg, S & Kirby, R 2020, 'Non-negative intensity for planar structures under stochastic excitation', Journal of Sound and Vibration, vol. 488, pp. 115652-115652.
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Kerferd, B, Eggler, D, Karimi, M & Kessissoglou, N 2020, 'Active acoustic cloaking of cylindrical shells in low Mach number flow', Journal of Sound and Vibration, vol. 479, pp. 115400-115400.
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The vibro-acoustic responses of a two-dimensional cylindrical shell in low Mach number flow are herein derived. The analytical model takes into account the structural elasticity and coupling of the shell vibration with its interior and exterior acoustic fields in the presence of a moving fluid. The cylindrical shell is modelled using Donnell-Mushtari theory. Taylor transformations are employed to transfer the convected wave equation into the ordinary wave equation which was then solved using scattering theory. Three excitation cases corresponding to a plane wave, an external monopole source and a radial point force applied directly to the shell are considered. Shell circumferential resonances and interior acoustic resonances are identified. Two active control strategies are then applied to acoustically cloak the cylindrical shell at its acoustic and structural resonances. The first control approach employs acoustic control sources in the exterior fluid domain. In the second approach, control forces are applied to directly excite the elastic shell, whereby the structural response is actively modified to manipulate the scattered and radiated acoustic fields arising from plane wave excitation of the shell. Results show that the second approach is superior in terms of both reduced control effort and cloaking of the global exterior domain. For both control approaches, the performance of the active cloak is shown to deteriorate if the convected flow field is not accounted for in the control process.

Khosravi, F, Hosseini, SA & Hayati, H 2020, 'Free and forced axial vibration of single walled carbon nanotube under linear and harmonic concentrated forces based on nonlocal theory', International Journal of Modern Physics B, vol. 34, no. 08, pp. 2050067-2050067.
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The aim of this paper is to investigate the free and forced axial vibrations under the two various linear and harmonic axial concentrated forces in zigzag single-walled carbon nanotube (SWCNT). Two different boundary conditions, namely clamped–clamped and clamped-free, are established. Eringen’s nonlocal elasticity is employed to justify the nonlocal behavior of constitutive relations. The governing equation and the associated boundary condition are derived based on Hamilton’s principle. In order to solve the derived equation numerically, the assumed modes method is utilized. In the free axial vibration section, the first three natural frequencies are obtained for the various values of the nonlocal parameter. The results are in good agreement in comparison with another study. The fundamental natural frequencies with respect to the nonlocal parameter of the case study as a semiconducting nanotube with boron nitride nanotube (BNNT) as a semiconducting nanotube and SWCNT (5,5) as a metallic nanotube are compared. The effects of the nonlocal parameter, thickness and ratio of the excitation-to-natural frequencies overtime on dimensional and nondimensional axial displacements are studied.

Kong, FH, Zhao, J, Zhao, L & Huang, S 2020, 'Analysis of Minima for Geodesic and Chordal Cost for a Minimal 2-D Pose-Graph SLAM Problem', IEEE Robotics and Automation Letters, vol. 5, no. 2, pp. 323-330.
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© 2016 IEEE. In this letter, we show that for a minimal 2D pose-graph SLAM problem, even in the ideal case of perfect measurements and spherical covariance, using geodesic distance (in 2D, the 'wrap function') to compare angles results in multiple suboptimal local minima. We numerically estimate regions of attraction to these local minima for some examples, give evidence to show that they are of nonzero measure, and that these regions grow in size as noise is added. In contrast, under the same assumptions, we show that the chordal distance representation of angle error has a unique minimum up to periodicity. For chordal cost, we find that initial conditions failing to converge to the global minimum are far fewer, fail because of numerical issues, and do not seem to grow with noise in our examples.

Li, W, Huang, L & Ji, J 2020, 'Globally exponentially stable periodic solution in a general delayed predator-prey model under discontinuous prey control strategy', Discrete & Continuous Dynamical Systems - B, vol. 25, no. 7, pp. 2639-2664.
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This paper studies the solution behaviour of a general delayed predator-prey model with discontinuous prey control strategy. The positiveness and boundeness of the solution of the system is firstly investigated using the comparison theorem. Then the sufficient conditions are derived for the existence of positive periodic solutions using the differential inclusion theory and the topological degree theory. Furthermore, the positive periodic solution is proved to be globally exponentially stable by employing the generalized Lyapunov approach. The global finite-time convergence is also discussed for the system state. Finally, the numerical simulations of four examples are given to validate the correctness of the theoretical results.

Li, W, Ji, J & Huang, L 2020, 'Dynamics of a controlled discontinuous computer worm system', Proceedings of the American Mathematical Society, vol. 148, no. 10, pp. 4389-4403.
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© 2020 American Mathematical Society This paper studies the dynamic behaviour of a computer worm system under a discontinuous control strategy. Some conditions for globally asymptotically stable solutions of the discontinuous system are obtained by using the Bendixson–Dulac theorem, Green’s formula, and the Lyapunov function. It is found that the solutions of the controlled computer worm system can converge to either of two local equilibrium points or the sliding equilibrium point on the discontinuous surface. It is shown that a threshold control strategy can effectively control the spread of computer viruses. The research results may be applicable to control other types of virus systems.

Li, W, Ji, J & Huang, L 2020, 'Global dynamic behavior of a predator–prey model under ratio-dependent state impulsive control', Applied Mathematical Modelling, vol. 77, pp. 1842-1859.
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© 2019 This paper studies the global dynamic behavior of a prey–predator model with square root functional response under ratio-dependent state impulsive control strategy. It is shown that the boundary equilibrium point of the controlled system is globally asymptotically stable. An order-k periodic orbit is obtained by employing the Brouwer's fixed point theorem. Furthermore, the critical values are determined for the existence of orbitally asymptotically stable order-1 and order-2 periodic orbits in finite time. These critical values play an important role in determining different kinds of order-k periodic orbits and can also be used for designing the control parameters to obtain the desirable dynamic behavior of the controlled prey–predator system. Moreover, it is found that the local equilibrium point is also globally asymptotically stable under the control strategy. Numerical examples are provided to validate the effectiveness and feasibility of the theoretical results.

Li, W, Ji, J, Huang, L & Wang, J 2020, 'Bifurcations and dynamics of a plant disease system under non-smooth control strategy', Nonlinear Dynamics, vol. 99, no. 4, pp. 3351-3371.
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© 2020, Springer Nature B.V. Mathematical models and analyses can assist in designing the control strategies to prevent the spread of infectious disease. The present paper investigates the bifurcations and dynamics of a plant disease system under non-smooth control strategy. The generalized Lyapunov approach is employed to perform the analysis of the plant disease model with non-smooth control. It is found that the controlled disease system can have three types of equilibria. The globally asymptotically attractor for each of three types of equilibria is determined by constructing Lyapunov functions and using Green’s Theorem. It is shown that the disease system can exhibit rich dynamic behaviors including globally stable equilibrium, stable pseudo-equilibrium and sliding mode bifurcations. The solution of the disease system can converge to the disease-free equilibrium, endemic equilibrium or sliding equilibrium on discontinuous surfaces. Biological implications of the obtained results are discussed for implementing the control strategies to the infectious plant diseases.

Li, W, Jiang, C, Lan, Z & Deng, M 2020, 'Thermal damage evaluation in nickel plate by nonlinear electromagnetic acoustic resonance technique', International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 835-842.
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Nickel and nickel-based composites are of vital importance in many fields, while temperature loading can greatly influence the strength and performance of the materials. Nondestructive evaluation and characterization of such thermal damage can be used to predict the failure of metallic structures, thermal barrier coatings and so on, especially in a non-contact way under certain strict circumstances, such as testing at high temperature or in radiative environment. Herein, a contactless ultrasonic technique employing electromagnetic acoustic transducers (EMATs) combined with the resonance ultrasound spectroscopy is applied to make up the low energy transition efficiency of EMATs and enhance the signal-to-noise ratio of ultrasonic testing signals. The method is adopted to assess the thermal damages of different levels in artificially heat loaded nickel plates. The damage sensitivity of third order harmonics generated from shear waves is discussed, along with linear ultrasonic features including wave velocity and attenuation. Experimental results show that the proposed nonlinear electromagnetic acoustic resonance (EMAR) technique can be used to evaluate the thermal damage in ferromagnetic material with improved reliability and sensitivity over linear ones.

Li, W, Jiang, C, Qing, X, Liu, L & Deng, M 2020, 'Assessment of low-velocity impact damage in composites by the measure of second-harmonic guided waves with the phase-reversal approach', Science Progress, vol. 103, no. 1, pp. 003685041988107-003685041988107.
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Structural strength and integrity of composites can be considerably affected by the low-velocity impact damage due to the unique characteristics of composites, such as layering bonded by adhesive and the weakness to impact. For such damage, there is an urgent need to develop advanced nondestructive testing approaches. Despite the fact that the second harmonics could provide information sensitive to the structural health condition, the diminutive amplitude of the measured second-order harmonic guided wave still limits the applications of the second-harmonic generation–based nonlinear guided wave approach. Herein, laminated composites suffered from low-velocity impact are characterized by use of nonlinear guided waves. An enhancement in the signal-to-noise ratio for the measure of second harmonics is achieved by a phase-reversal method. Results obtained indicate a monotonic correlation between the impact-induced damage in composites and the relative acoustic nonlinear indicator of guided waves. The experimental finding in this study shows that the measure of second-order harmonic guided waves with a phase-reversal method can be a promising indicator to impact damage rendering in an improved and reliable manner.

Liu, J, Li, H, Ji, J & Luo, J 2020, 'Group-Bipartite Consensus in the Networks With Cooperative-Competitive Interactions', IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 67, no. 12, pp. 3292-3296.
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© 2004-2012 IEEE. This brief addresses the group-bipartite consensus problem of multi-agent systems with cooperative-competitive interactions. By combining the characteristics of group consensus and bipartite consensus, the concept of group-bipartite consensus is introduced to specify multiple bipartite consensus behavior. A distributed control protocol is then proposed for the topology graphs with acyclic partition and sign-balanced couples. The network topology studied in this brief eliminates the constraint that negative links can only exist between different groups, and thus the weights between agents in the same group can be either positive or negative. Some necessary and sufficient conditions for solving group-bipartite consensus problems are established by constructing a new form of the Laplacian matrix associated with the directed communication graphs. A simulation example is given to validate the theoretical results.

Lu, W & Liu, D 2020, 'A2: Extracting cyclic switchings from DOB-nets for rejecting excessive disturbances', Neurocomputing, vol. 400, pp. 161-172.
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© 2020 Reinforcement Learning (RL) is limited in practice by its poor explainability, which is responsible for insufficient trustiness from users, unsatisfied interpretation for human intervention, inadequate analysis for future improvement, etc. This paper seeks to partially characterize the interplay between dynamical environments and a previously-proposed Disturbance OBserver net (DOB-net). The DOB-net is trained via RL and offers optimal control for a set of Partially Observable Markovian Decision Processes (POMDPs). The transition function of each POMDP is largely determined by the environments (excessive external disturbances). This paper proposes an Attention-based Abstraction (A2) approach to extract a finite-state automaton, referred to as a Key Moore Machine Network (KMMN), to capture the switching mechanisms exhibited by the DOB-net in dealing with multiple such POMDPs. A2 first quantizes the controlled platform by learning continuous-discrete interfaces. Then it extracts the KMMN by finding the key hidden states and transitions that attract sufficient attention from the DOB-net. Within the resultant KMMN, three patterns of cyclic switchings (between key hidden states) are found, and saturated controls are shown synchronized with unknown disturbances. Interestingly, the found switchings have previously appeared in the control design for often-saturated systems. They are interpreted via an analogy to the discrete-event subsystem of hybrid control.

M. Vanaki, S, Holmes, D, Saha, SC, Chen, J, Brown, RJ & Jayathilake, PG 2020, 'Muco-ciliary clearance: A review of modelling techniques', Journal of Biomechanics, vol. 99, pp. 109578-109578.
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Ma, H, Wang, Y, Xiong, R, Kodagoda, S & Tang, L 2020, 'DeepGoal: Learning to drive with driving intention from human control demonstration', Robotics and Autonomous Systems, vol. 127, pp. 103477-103477.
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© 2020 Elsevier B.V. Recent research on automotive driving has developed an efficient end-to-end learning mode that directly maps visual input to control commands. However, it models distinct driving variations in a single network, which increases learning complexity and is less adaptive for modular integration. In this paper, we re-investigate human's driving style and propose to learn an intermediate driving intention region to relax the difficulties in end-to-end approach. The intention region follows both road structure in image and direction towards goal in public route planner, which addresses visual variations only and figures out where to go without conventional precise localization. Then the learned visual intention is projected on vehicle local coordinate and fused with reliable obstacle perception to render a navigation score map that is widely used for motion planning. The core of the proposed system is a weakly-supervised cGAN-LSTM model trained to learn driving intention from human demonstration. The adversarial loss learns from limited demonstration data with one local planned route and enables reasoning of multi-modal behaviors with diverse routes while testing. Comprehensive experiments are conducted with real-world datasets. Results indicate the proposed paradigm can produce more consistent motion commands with human demonstration and shows better reliability and robustness to environment change. Our code is available at https://github.com/HuifangZJU/visual-navigation.

Maxit, L, Guasch, O, Meyer, V & Karimi, M 2020, 'Noise radiated from a periodically stiffened cylindrical shell excited by a turbulent boundary layer', Journal of Sound and Vibration, vol. 466, pp. 115016-115016.
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© 2019 Elsevier Ltd This work proposes a semi-analytical method to model the vibroacoustic behavior of submerged cylindrical shells periodically stiffened by axisymmetric frames and excited by a homogeneous and fully developed turbulent boundary layer (TBL). The process requires the computation of the TBL wall-pressure cross spectral density function and the sensitivity functions for stiffened cylindrical shells. The former is deduced from an existent TBL model and the latter are derived from a wavenumber-point reciprocity principle and a spectral formulation of the problem. The stiffeners' dynamic behavior is introduced in the formulation through circumferential admittances that are computed by a standard finite element code using shell elements. Four degrees of freedom are taken into account for the coupling between the shell and the stiffeners: three translation directions and one tangential rotation. To investigate the effect of the stiffeners on the radiated noise, two case studies are considered. The first one examines a fluid-loaded cylindrical shell with regularly spaced simple supports. The influence of Bloch-Floquet waves and the support spacing on the noise radiation are highlighted. The second case study inspects the fluid-loaded cylindrical shell with two different periodic ring stiffeners, namely stiffeners with T-shaped and I-shaped cross-sections. Their influence on the vibroacoustics of the shell is thoroughly analyzed.

McCourt, LR, Ruppert, MG, Routley, BS, Indirathankam, SC & Fleming, AF 2020, 'A comparison of gold and silver nanocones and geometry optimisation for tip‐enhanced microscopy', Journal of Raman Spectroscopy, vol. 51, no. 11, pp. 2208-2216.
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AbstractIn this article, boundary element method simulations are used to optimise the geometry of silver and gold nanocone probes to maximise the localised electric field enhancement and tune the near‐field resonance wavelength. These objectives are expected to maximise the sensitivity of tip‐enhanced Raman microscopes. Similar studies have used limited parameter sets or used a performance metric other than localised electric field enhancement. In this article, the optical responses for a range of nanocone geometries are simulated for excitation wavelengths ranging from 400 to 1000 nm. Performance is evaluated by measuring the electric field enhancement at the sample surface with a resonant illumination wavelength. These results are then used to determine empirical models and derive optimal nanocone geometries for a particular illumination wavelength and tip material. This article concludes that gold nanocones are expected to provide similar performance to silver nanocones at red and near‐infrared wavelengths, which is consistent with other results in the literature. In this article, 633 nm is determined to be the shortest usable illumination wavelength for gold nanocones. Below this limit, silver nanocones will provide superior enhancement. The use of gold nanocone probes is expected to dramatically improve probe lifetime, which is currently measured in hours for silver coated probes. Furthermore, the elimination of passivation coatings is expected to enable smaller probe radii and improved topographical resolution.

Melnikov, A, Maeder, M, Friedrich, N, Pozhanka, Y, Wollmann, A, Scheffler, M, Oberst, S, Powell, D & Marburg, S 2020, 'Acoustic metamaterial capsule for reduction of stage machinery noise', The Journal of the Acoustical Society of America, vol. 147, no. 3, pp. 1491-1503.
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Noise mitigation of stage machinery can be quite demanding and requires innovative solutions. In this work, an acoustic metamaterial capsule is proposed to reduce the noise emission of several stage machinery drive trains, while still allowing the ventilation required for cooling. The metamaterial capsule consists of c-shape meta-atoms, which have a simple structure that facilitates manufacturing. Two different metamaterial capsules are designed, simulated, manufactured, and experimentally validated that utilize an ultra-sparse and air-permeable reflective meta-grating. Both designs demonstrate transmission loss peaks that effectively suppress gear mesh noise or other narrow band noise sources. The ventilation by natural convection was numerically verified, and was shown to give adequate cooling, whereas a conventional sound capsule would lead to overheating. The noise spectra of three common stage machinery drive trains are numerically modelled, enabling one to design meta-gratings and determine their noise suppression performance. The results fulfill the stringent stage machinery noise limits, highlighting the benefit of using metamaterial capsules of simple c-shape structure.

Moghaddam, HA, Sarmadian, A, Asnaashari, A, Joushani, HAN, Islam, MS, Saha, SC, Ghasemi, G & Shafaee, M 2020, 'Condensation heat transfer and pressure drop characteristics of Isobutane in horizontal channels with twisted tape inserts', International Journal of Refrigeration, vol. 118, pp. 31-40.
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Mojumder, S, Saha, S, Saha, S, Rahman, R & Saha, SC 2020, 'Effect of Magnetic Field on Double Diffusive Natural Convection Inside a Square Cavity with Isothermal Hollow Insert', IOP Conference Series: Materials Science and Engineering, vol. 831, no. 1, pp. 012010-012010.
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Abstract A numerical study is carried out to analyze both heat and mass transfer phenomena in the presence of an external magnetic field inside a square cavity with an isothermal hollow circular insert located at the centre of the cavity. In the present work, the effects of Hartmann number, Lewis number and buoyancy ratio at constant Rayleigh and Prandtl numbers are investigated simultaneously to understand the importance of these parameters on the characteristics of double diffusive natural convection. Galerkin finite element method is employed for the numerical simulations. Grid sensitivity test and code validation are performed prior to confirm the numerical accuracy of the solution. Quantitative comparison is presented by showing the influence of Hartmann and Lewis numbers for different buoyancy ratios on average Nusselt and Sherwood numbers. It is found that increment of Hartmann number results in lower heat and mass transfer rates. Higher value of Lewis number produces elevated mass transfer rate. However, Lewis number has negative impact on heat transfer rate. Moreover, buoyancy ratio has significant effect on heat and mass transfer inside the cavity.

Moore, SI, Ruppert, MG & Yong, YK 2020, 'AFM Cantilever Design for Multimode Q Control: Arbitrary Placement of Higher Order Modes', IEEE/ASME Transactions on Mechatronics, vol. 25, no. 3, pp. 1389-1397.
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Munasinghe, N & Paul, G 2020, 'Ultrasonic-Based Sensor Fusion Approach to Measure Flow Rate in Partially Filled Pipes', IEEE Sensors Journal, vol. 20, no. 11, pp. 6083-6090.
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Flow rate measurement in pipes is essential for many applications. Thus, there have been a variety of flow meters developed that incorporate different technologies. However, a typical limitation in flow meters is that the pipe must be full in order to get an accurate flow reading. In many cases, this is not possible for practical reasons. When the pipe is full, ultrasonic flow meters can calculate the flow rate using known properties of the pipe and fluid, namely the cross-section, propagation path and fluid sound velocity. However, when the pipe is only partially filled, the propagation path is unknown which leads to an inability to calculate the correct flow rate. This paper presents a cost-effective sensor fusion approach to extend the capabilities of transit time ultrasonic flow meters to handle such scenarios. The approach determines the propagation path using capacitance-based level sensing, combined with fluid velocities ascertained via an ultrasonic sensor, leading to a significantly more accurate estimation of flow rates. Experiments in low flow rate situations validated the efficacy of the proposed model, with a 92% reduction of mean error in the lowest water height when compared to a conventional ultrasonic flow meter.

Nerse, C, Wang, S & Goo, S 2020, 'Effect of damping distribution on coupling in panel–cavity systems: Conditions for optimality through a modal approach', International Journal of Mechanical Sciences, vol. 187, pp. 105908-105908.
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© 2020 In this study, we examine an acoustic–structure interaction problem for nonproportionally damped systems. Coupled responses for a structure and acoustic enclosure are derived using a modified modal coupling formulation. Uncoupled modal patterns are used to assess the coupling effectiveness. Comparison with a proportional damping case reveals characteristics that associate complex modes with damping optimality. Such an interrelation is investigated through topology optimization of a damping layer to minimize the acoustic pressure in the cavity. The findings of this numerical study indicate a spatial relation between the imaginary part of the coupling coefficient and the optimal damping layout. Further investigation of complex modal patterns with wave interpretation shows that the optimal damping characteristics of the panel can be expressed by a spatially varying nonproportional damping index. Case studies involving various nonproportional damping configurations are presented to confirm the significant correlation with respect to observed phenomena.

Nikoloska, R, Bykerk, L, Vitanage, D, Valls Miro, J, Chen, F, Wang, Y & Liang, B 2020, 'Enhancing Sydney Water’s leak prevention through acoustic monitoring', Water e-Journal, vol. 5, no. 2, pp. 1-15.
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Niu, F, Zhao, S, Qiu, X & Zhang, D 2020, 'A note on wind velocity and pressure spectra inside compact spherical porous microphone windscreens', The Journal of the Acoustical Society of America, vol. 147, no. 1, pp. EL43-EL49.
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Simultaneous measurements of wind velocity and pressure fluctuations were conducted in a wind tunnel to investigate the wind noise source inside compact spherical open celled porous windscreens. The existing outdoor wind noise models are found to be inadequate to predict the wind noise inside a wind tunnel. This paper proposes a model to predict the interior stagnation pressure, which agrees with the wind noise measured inside the windscreen within a bandwidth, where the exterior turbulence-turbulence interaction pressure overestimates the wind noise level. The limitations of the proposed model and other potential sources for wind noise inside porous windscreens are discussed.

Nolte, V, Sindram, T, Mazarov, J & Deuse, J 2020, 'Industrial Data Science erfolgreich implementieren', ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 115, no. 10, pp. 734-737.
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Nolte, V, Sindram, T, Mazarov, J & Deuse, J 2020, 'Industrial Data Science erfolgreich implementieren', Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 115, no. 10, pp. 734-737.
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Abstract Die Potenziale von Industrial Data Science haben Unternehmen unlängst erkannt, scheitern jedoch an deren Umsetzung. In diesem Beitrag werden die Ergebnisse einer branchenübergreifenden Interviewstudie mit über 50 Führungskräften und Fachexperten vorgestellt, wobei Durchführungshemmnisse und Erfolgsfaktoren identifiziert werden. Zudem werden Anforderungen an das Change Management diskutiert sowie konkrete Handlungsempfehlungen für Unternehmen gegeben.

Oberst, S, Halkon, B, Ji, J & Brown, T 2020, 'Preface', Vibration Engineering for a Sustainable Future: Active and Passive Noise and Vibration Control, Vol. 1, vol. 1, pp. v-vi.

Oberst, S, Lai, JCS, Martin, R, Halkon, BJ, Saadatfar, M & Evans, TA 2020, 'Revisiting stigmergy in light of multi-functional, biogenic, termite structures as communication channel', Computational and Structural Biotechnology Journal, vol. 18, pp. 2522-2534.
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Termite mounds are fascinating because of their intriguing composition of nu- merous geometric shapes and materials. However, little is known about these structures, or of their functionalities. Most research has been on the basic com- position of mounds compared with surrounding soils. There has been some targeted research on the thermoregulation and ventilation of the mounds of a few species of fungi-growing termites, which has generated considerable inter- est from human architecture. Otherwise, research on termite mounds has been scattered, with little work on their explicit properties.This review is focused on how termites design and build functional structures as nest, nursery and food storage; for thermoregulation and climatisation; as defence, shelter and refuge; as a foraging tool or building material; and for colony communication, either as in indirect communication (stigmergy) or as an information channel essential for direct communication through vibrations (biotremology).Our analysis shows that systematic research is required to study the prop- erties of these structures such as porosity and material composition. High res- olution computer tomography in combination with nonlinear dynamics and methods from computational intelligence may provide breakthroughs in un- veiling the secrets of termite behaviour and their mounds. In particular, the ex- amination of dynamic and wave propagation properties of termite-built struc- tures in combination with a detailed signal analysis of termite activities is re- quired to better understand the interplay between termites and their nest as superorganism. How termite structures serve as defence in the form of disguis- ing acoustic and vibration signals from detection by predators, and what role local and global vibration synchronisation plays for building are open ques- tions that need to be addressed to provide insights into how termites utilise materials to thrive in a world of predators and competitors.

Patten, T, Park, K & Vincze, M 2020, 'DGCM-Net: Dense Geometrical Correspondence Matching Network for Incremental Experience-based Robotic Grasping', Frontiers in Robotics and AI, vol. 7, p. 120.
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This article presents a method for grasping novel objects by learning fromexperience. Successful attempts are remembered and then used to guide futuregrasps such that more reliable grasping is achieved over time. To generalisethe learned experience to unseen objects, we introduce the dense geometriccorrespondence matching network (DGCM-Net). This applies metric learning toencode objects with similar geometry nearby in feature space. Retrievingrelevant experience for an unseen object is thus a nearest neighbour searchwith the encoded feature maps. DGCM-Net also reconstructs 3D-3D correspondencesusing the view-dependent normalised object coordinate space to transform graspconfigurations from retrieved samples to unseen objects. In comparison tobaseline methods, our approach achieves an equivalent grasp success rate.However, the baselines are significantly improved when fusing the knowledgefrom experience with their grasp proposal strategy. Offline experiments with agrasping dataset highlight the capability to generalise within and betweenobject classes as well as to improve success rate over time from increasingexperience. Lastly, by learning task-relevant grasps, our approach canprioritise grasps that enable the functional use of objects.

Razavi Bazaz, S, Mashhadian, A, Ehsani, A, Saha, SC, Krüger, T & Ebrahimi Warkiani, M 2020, 'Computational inertial microfluidics: a review', Lab on a Chip, vol. 20, no. 6, pp. 1023-1048.
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Schematic illustration of various kinds of geometries used for inertial microfluidics.

Romeijn, T, Wells, B, Wei, D & Paul, G 2020, 'Investigation into the shear property of thin-walled additively manufactured structures using staggered fused filament fabrication', Additive Manufacturing, vol. 35, pp. 101259-101259.
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© 2020 Additive manufacturing techniques, such as Fused Filament Fabrication (FFF), are rapidly revolutionising the manufacturing and mining sectors. This paper presents an investigation into the shear behaviour of thin-walled FFF structures, printed via a proposed ‘offset method’. Firstly, an alternative method of filament positioning in material extrusion is proposed, referred to as the ‘offset method’, which aims to reduce the volume of empty cavities between deposited material. Then the shear properties, density properties, and cross-sectional void surface area are compared to structures printed using the aligned printing method. Experimental results on solid printed (no infill) samples, through four different-sized nozzles, have shown the newly proposed method produces a 6.5 % increase in density and a 7.2 % improvement in maximum in-plane shear stress per millimetre increase in nozzle size, compared with the aligned method of FFF. The offset method was found to produce a material with increased interlayer contact, compared to the aligned method, which results in a higher fictitious shear stress modulus. The effect of the increased interlayer contact on the fictitious shear modulus and real shear stress was investigated using a FEM analysis of the unit cells. In short, using the same feedstock material, the offset method produces a stiffer material with a higher fictitious shear strength than the aligned method of FFF printing.

Roth, N, Deuse, J & Biedermann, H 2020, 'A framework for System Excellence assessment of production systems, based on lean thinking, business excellence, and factory physics', International Journal of Production Research, vol. 58, no. 4, pp. 1074-1091.
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© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This article proposes a production system framework that synthesises lean production, business excellence, and factory physics. The framework, which draws on a deep state-of-the-art understanding, consists of a performance measurement system supporting the achievement of a target condition based on variability and lead time reduction, as well as approaches of continuous improvement. Based on four types of excellence, a System Excellence value is calculated, indicating the distance from a target condition and thus displaying relevant improvement potential. As a key result, the framework proposed provides a contribution to knowledge, as it combines the aforementioned schools of thought, resulting in a holistic framework for action. The measurement system offers a high level of robustness, as it draws on diverse data sources and reflects on the dynamic behaviour over time. It has been successfully implemented in automotive manufacturing plants worldwide, which may suggest considerable practical relevance. Another key result of this research is that through applying the framework, important bottom-line indicators, such as lead time, failure costs, or productivity, could be improved. As the plants are typical automotive industry high-volume plants, it is proposed that the solutions presented offer a suitable standard for this industry and type of plant.

Rouf, RA, Jahan, N, Alam, KCA, Sultan, AA, Saha, BB & Saha, SC 2020, 'Improved cooling capacity of a solar heat driven adsorption chiller', Case Studies in Thermal Engineering, vol. 17, pp. 100568-100568.
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Ruppert, MG, Bartlett, NJ, Yong, YK & Fleming, AJ 2020, 'Amplitude noise spectrum of a lock-in amplifier: Application to microcantilever noise measurements', Sensors and Actuators A: Physical, vol. 312, pp. 112092-112092.
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Saha, S, Barua, S, Kushwaha, B, Subedi, S, Hasan, MN & Saha, SC 2020, 'Conjugate natural convection in a corrugated solid partitioned differentially heated square cavity', Numerical Heat Transfer, Part A: Applications, vol. 78, no. 10, pp. 541-559.
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© 2020 Taylor & Francis Group, LLC. Conjugate natural convection heat transfer inside a differentially heated square cavity having a heat conducting and sinusoidal corrugated solid partition has been investigated numerically in the present study. The fluid flow and the heat transfer within the cavity are governed by two-dimensional Navier–Stokes and energy equations, and those are solved using the finite element method. Numerical simulation is carried out for a wide range of Rayleigh number (103 ≤ Ra ≤ 109) with a fixed Prandtl number (Pr = 0.71) since the working fluid in the cavity is considered as air. The variations of both corrugation amplitude and corrugation frequency of the sinusoidal partition wall on the average Nusselt number of the heated wall are observed in order to assess the influence of the roughness of the solid partition on the heat transfer characteristics of the cavity. Moreover, different types of partition material are selected to scrutinize the effect of thermal conductivity of the solid partition on the heat transfer performance. Finally, a correlation is proposed to predict the average Nusselt number of the heated wall of the cavity from the governing parameters (such as Rayleigh number, corrugation frequency and thermal conductivity ratio) within the selected range of the present investigation.

Sarmadian, A, Moghaddam, HA, Asnaashari, A, Joushani, HAN, Moosavi, M, Islam, MS, Saha, SC & Shafaee, M 2020, 'Flow boiling heat transfer and pressure drop characteristics of Isobutane in horizontal channels with twisted tapes', International Journal of Heat and Mass Transfer, vol. 162, pp. 120345-120345.
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© 2020 Elsevier Ltd Using twisted tapes as a passive method for heat transfer improvement in a two-phase flow heat exchanger is experimentally studied. The test evaporator is a copper channel with a length of 1000 mm and an internal diameter of 8.1 mm which is installed horizontally. Three twisted tapes with twist ratios of 4, 10, and 15 are used at refrigerant vapor qualities in the range of 0.1–0.8 and refrigerant mass velocities between 160-350 kgm−2s−1. The natural refrigerant Isobutane (R600a) is chosen as the working fluid because it is environmentally friendly. According to the experiments, installing twisted tapes inside the channel augments both heat transfer rate and pressure drops over the plain channel. It is also observed that for both plain and twisted tape inserted channels, the values of heat transfer coefficients and pressure losses grow by giving rise to the refrigerant mass velocity and vapor quality. Results showed that the system performance factor varied between 0.44–1.09 offering that using twisted tapes as a turbulator is beneficial under specific operating conditions. The empirical data showed that there is an optimum value of the working fluid mass velocity at which the performance of twisted tape inserted channels is higher.

Schmitt, J, Bönig, J, Borggräfe, T, Beitinger, G & Deuse, J 2020, 'Predictive model-based quality inspection using Machine Learning and Edge Cloud Computing', Advanced Engineering Informatics, vol. 45, pp. 101101-101101.
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Sepehrirahnama, S & Lim, K-M 2020, 'Acoustophoretic agglomeration patterns of particulate phase in a host fluid', Microfluidics and Nanofluidics, vol. 24, no. 12.
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Sepehrirahnama, S, Ong, ET, Lee, HP & Lim, KM 2020, 'Numerical Modeling of Free-Surface Wave Effects on Flexural Vibration of Floating Structures', International Journal of Computational Methods, vol. 17, no. 05, pp. 1940016-1940016.
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To investigate flexural vibration of structures in a fluid, a numerical algorithm was developed to relate the added mass and damping effects of the fluid to each mode of vibration. These are separate from the traditional added mass associated with rigid body motion, such as the translational motion along Cartesian axes. In this formulation, small-amplitude free surface waves were accounted for by using a nonsingular implementation of the free-surface Green’s function for a potential flow solver based on Boundary Element Method. The formulation was applied to the forced vibration of structures, namely, a hemispherical shell and a reinforced half cylinder with typical dimensions of ships and offshore structures, to obtain their dynamic response at various excitation frequencies. It is observed that resonance frequency of the structure, in contact with water, decreases due to the added mass effect. The influence of the free-surface wave on the fluid loading was investigated for large structures. It is simpler to relate the fluid added mass to mode shapes rather than distribution of fluid load over wetted surface of the structure in engineering simulations. Moreover, it is found that the vibration energy radiated away by the fluid surface wave has little influence on the vibration response of the shell structures.

Shakor, P, Nejadi, S, Sutjipto, S, Paul, G & Gowripalan, N 2020, 'Effects of deposition velocity in the presence/absence of E6-glass fibre on extrusion-based 3D printed mortar', Additive Manufacturing, vol. 32, pp. 101069-101069.
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© 2020 Additive Manufacturing (AM) technologies are widely used in various fields of industry and research. Continual research has enabled AM technologies to be considered as a feasible substitute for certain applications in the construction industry, particularly given the advances in the use of glass fibre reinforced mortar. An investigation of the resulting mechanical properties of various mortar mixes extruded using a robotic arm is presented. The nozzle paths were projected via ‘spline’ interpolation to obtain the desired trajectory and deposition velocity in the reference frame of the manipulator. Along each path, various mortar mixes, with and without chopped glass fibre, were deposited at different velocities. Tests were conducted to determine their mechanical performance when incorporated in printed structures with different layers (1, 2, 4 and 6 layers). The results are compared with those of conventional cast-in-place mortar. In this study, the mixes consist of ordinary Portland cement, fine sand, chopped glass fibres (6 mm) and chemical admixtures, which are used to print prismatic- and cubic-shaped specimens. Mechanical strength tests were performed on the printed specimens to evaluate the behaviour of the materials in the presence and absence of glass fibre. Robot end-effector velocity tests were performed to examine the printability and extrudability of the mortar mixes. Finally, horizontal and vertical line printing tests were used to determine the workability, buildability and uniformity of the mortar mix and to monitor the fibre flow directions in the printed specimens. The results show that printed specimens with glass fibre have enhanced compressive strength compared with specimens without glass fibre.

Shukla, N, Merigó, JM, Lammers, T & Miranda, L 2020, 'Half a century of computer methods and programs in biomedicine: A bibliometric analysis from 1970 to 2017', Computer Methods and Programs in Biomedicine, vol. 183, pp. 105075-105075.
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© 2019 Background and Objective: Computer Methods and Programs in Biomedicine (CMPB) is a leading international journal that presents developments about computing methods and their application in biomedical research. The journal published its first issue in 1970. In 2020, the journal celebrates the 50th anniversary. Motivated by this event, this article presents a bibliometric analysis of the publications of the journal during this period (1970–2017). Methods: The objective is to identify the leading trends occurring in the journal by analysing the most cited papers, keywords, authors, institutions and countries. For doing so, the study uses the Web of Science Core Collection database. Additionally, the work presents a graphical mapping of the bibliographic information by using the visualization of similarities (VOS) viewer software. This is done to analyze bibliographic coupling, co-citation and co-occurrence of keywords. Results: CMPB is identified as a leading and core journal for biomedical researchers. The journal is strongly connected to IEEE Transactions on Biomedical Engineering and IEEE Transactions on Medical Imaging. Paper from Wang, Jacques, Zheng (published in 1995) is its most cited document. The top author in this journal is James Geoffrey Chase and the top contributing institution is Uppsala U (Sweden). Most of the papers in CMPB are from the USA followed by the UK and Italy. China and Taiwan are the only Asian countries to appear in the top 10 publishing in CMPB. A keyword co-occurrences analysis revealed strong co-occurrences for classification, picture archiving and communication system (PACS), heart rate variability, survival analysis and simulation. Keywords analysis for the last decade revealed that machine learning for a variety of healthcare problems (including image processing and analysis) dominated other research fields in CMPB. Conclusions: It can be concluded that CMPB is a world-renowned publication outlet for biomedical re...

Singh, P, Raghav, V, Padhmashali, V, Paul, G, Islam, MS & Saha, SC 2020, 'Airflow and Particle Transport Prediction through Stenosis Airways', International Journal of Environmental Research and Public Health, vol. 17, no. 3, pp. 1119-1119.
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Airflow and particle transport in the human lung system is influenced by biological and other factors such as breathing pattern, particle properties, and deposition mechanisms. Most of the studies to date have analyzed airflow characterization and aerosol transport in idealized and realistic models. Precise airflow characterization for airway stenosis in a digital reference model is lacking in the literature. This study presents a numerical simulation of airflow and particle transport through a stenosis section of the airway. A realistic CT-scan-based mouth–throat and upper airway model was used for the numerical calculations. Three different models of a healthy lung and of airway stenosis of the left and right lung were used for the calculations. The ANSYS FLUENT solver, based on the finite volume discretization technique, was used as a numerical tool. Proper grid refinement and validation were performed. The numerical results show a complex-velocity flow field for airway stenosis, where airflow velocity magnitude at the stenosis section was found to be higher than that in healthy airways. Pressure drops at the mouth–throat and in the upper airways show a nonlinear trend. Comprehensive pressure analysis of stenosis airways would increase our knowledge of the safe mechanical ventilation of the lung. The turbulence intensities at the stenosis sections of the right and left lung were found to be different. Deposition efficiency (DE) increased with flow rate and particle size. The findings of the present study increase our understanding of airflow patterns in airway stenosis under various disease conditions. More comprehensive stenosis analysis is required to further improve knowledge of the field.

Sun, G, Wang, L, Chen, D & Luo, Q 2020, 'Tensile performance of basalt fiber composites with open circular holes and straight notches', International Journal of Mechanical Sciences, vol. 176, pp. 105517-105517.
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© 2020 Elsevier Ltd Basalt fiber composites have attracted increasing attention in recent years due to their advantages over carbon fiber composites in many aspects such as lower cost, environmental friendliness, superior heat resistance and ductility. Notches in structural components are unavoidable in practical applications. In the present study, the effects of notch shape and size on the tensile properties of basalt fiber laminates were investigated by experiment, finite element analysis and theoretical calculation. Specimens were prepared using laminates reinforced by plain woven basalt or carbon fiber fabrics and machined with an open circular hole or straight notch. Standard tensile tests were conducted and recorded using digital image correlation, aiming to measure the full-field surface strain. Continuum damage mechanics based finite element models were developed to predict stress concentration factors and failure processes of notched specimens. The characteristic distances of the stress criterion models were calibrated by the experimental results of un-notched and notched specimens so that failure of basalt fiber laminates with circular and straight notches could be analytically predicted.

Thiyagarajan, K, Kodagoda, S, Ranasinghe, R, Vitanage, D & Iori, G 2020, 'Robust Sensor Suite Combined With Predictive Analytics Enabled Anomaly Detection Model for Smart Monitoring of Concrete Sewer Pipe Surface Moisture Conditions', IEEE Sensors Journal, vol. 20, no. 15, pp. 8232-8243.
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Ulapane, N, Thiyagarajan, K, Hunt, D & Valls Miro, J 2020, 'Quantifying the Relative Thickness of Conductive Ferromagnetic Materials Using Detector Coil-Based Pulsed Eddy Current Sensors', Journal of Visualized Experiments, vol. 155, no. 155.
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Thickness quantification of conductive ferromagnetic materials by means of non-destructive evaluation (NDE) is a crucial component of structural health monitoring of infrastructure, especially for assessing the condition of large diameter conductive ferromagnetic pipes found in the energy, water, oil, and gas sectors. Pulsed eddy current (PEC) sensing, especially detector coil-based PEC sensor architecture, has established itself over the years as an effective means for serving this purpose. Approaches for designing PEC sensors as well as processing signals have been presented in previous works. In recent years, the use of the decay rate of the detector coil-based time domain PEC signal for the purpose of thickness quantification has been studied. Such works have established that the decay rate-based method holds generality to the detector coil-based sensor architecture, with a degree of immunity to factors such as sensor shape and size, number of coil turns, and excitation current. Moreover, this method has shown its effectiveness in NDE of large pipes made of grey cast iron. Following such literature, the focus of this work is explicitly PEC sensor detector coil voltage decay rate-based conductive ferromagnetic material thickness quantification. However, the challenge faced by this method is the difficulty of calibration, especially when it comes to applications such as in situ pipe condition assessment since measuring electrical and magnetic properties of certain pipe materials or obtaining calibration samples is difficult in practice. Motivated by that challenge, in contrast to estimating actual thickness as done by some previous works, this work presents a protocol for using the decay rate-based method to quantify relative thickness (i.e., thickness of a particular location with respect to a maximum thickness), without the requirement for calibration.

Wang, G, Ji, J & Zhou, J 2020, 'Stochastic distribution synchronization and pinning control for complex heterogeneous dynamical networks', Asian Journal of Control, vol. 22, no. 4, pp. 1547-1564.
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AbstractThis paper investigates the stochastic synchronization and pinning control in the sense of probability distribution for a general model of complex heterogeneous dynamical networks subjected to stochastic disturbances. Some generic stochastic synchronization criteria are established for both cases of undirected and directed topology by using the ergodic theory on stochastic dynamical systems. Compared with most existing studies on the stochastic synchronization in the sense of mean square, it is demonstrated that the concept of stochastic distribution synchronization can well characterize the realistic structure and essential nature of complex practical stochastic systems. Subsequently, two representative examples of complex heterogeneous dynamical networks, namely coupled stochastic Duffing oscillators and coupled FitzHugh‐Nagumo neuron oscillators, are given to illustrate and numerically verify the theoretical results.

Wang, K, Ruppert, MG, Manzie, C, Nesic, D & Yong, YK 2020, 'Adaptive Scan for Atomic Force Microscopy Based on Online Optimization: Theory and Experiment', IEEE Transactions on Control Systems Technology, vol. 28, no. 3, pp. 869-883.
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Wang, K, Ruppert, MG, Manzie, C, Nesic, D & Yong, YK 2020, 'Scan Rate Adaptation for AFM Imaging Based on Performance Metric Optimization', IEEE/ASME Transactions on Mechatronics, vol. 25, no. 1, pp. 418-428.
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Wang, Y, Sun, H, Huang, S & Song, Y 2020, 'Description of stability for linear time‐invariant systems based on the first curvature', Mathematical Methods in the Applied Sciences, vol. 43, no. 2, pp. 486-511.
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This paper focuses on using the first curvature κ(t) of trajectory to describe the stability of linear time‐invariant system. We extend the results for two and three‐dimensional systems (Wang, Sun, Song et al, arXiv:1808.00290) to n‐dimensional systems. We prove that for a system , (a) if there exists a measurable set whose Lebesgue measure is greater than zero, such that or does not exist for any initial value in this set, then the zero solution of the system is stable; (b) if the matrix A is invertible, and there exists a measurable set whose Lebesgue measure is greater than zero, such that for any initial value in this set, then the zero solution of the system is asymptotically stable.

Wang, Y, Xia, J, Luo, Z, Yan, H, Sun, J & Lü, E 2020, 'Self-supporting topology optimization method for selective laser melting', Additive Manufacturing, vol. 36, pp. 101506-101506.
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© 2020 Elsevier B.V. The design of self-supporting structures is critical for the selective laser melting (SLM)-based 3D printing techniques. However, the control of the overhang feature conflicts with the mechanical performance of the structure. This paper proposes an approach to achieve the self-supporting structural design to facilitate the SLM process. Printable overhang heights of samples under various overhang angles are investigated through experimental tests, and the maximum overhang heights are mathematically related to the corresponding critical overhang angle. Subsequently, this relationship is incorporated into the topology optimization formulation to realize the optimized self-supporting structures. The SIMP (solid isotropic material with penalization) method is used to conduct topology optimization. An effective filtering strategy with the overhang restrictions is developed to eliminate the material parts that cannot be supported from below. A typical beam structure to maximize the stiffness is used as a numerical example to demonstrate the proposed method. The numerical results show that the restrictions with both the overhang angles and heights can generate optimized structures with better performance than those only with the overhang angle constraint. In addition, prototypes are used to validate the manufacturability of the topologically optimized designs.

Wang, Z, Zhang, W, Luo, Q, Zheng, G, Li, Q & Sun, G 2020, 'A novel failure criterion based upon forming limit curve for thermoplastic composites', Composites Part B: Engineering, vol. 202, pp. 108320-108320.
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© 2020 Elsevier Ltd This study aims to explore failure mechanism and failure criteria of carbon fiber reinforced polypropylene (CFRPP) by presenting a novel notch-shaped design of specimens with two different fiber orientations (0/90)4 and (+45/-45)4 subject to stamping process under room temperature. Two forming limit curves/diagrams (FLCs/FLDs) were established based upon the minor strain and major strain, as well as the developed equivalent fiber strain combined with a ratio of minor to major strain (SR), respectively. A novel notch-shaped design enables to minimize the influence of fiber orientation on failure modes and FLC of CFRPP effectively. Not only did the equivalent fiber strain based FLC reflect the failure mode in terms of a certain SR value, but also showed the failure strain on fiber bundles quantitatively. Finite element (FE) models involving the new failure criteria (FLC) were developed on the basis of the experimental results. It was found that such a new FE model is able to better predict the results than those with the conventional maximum strain or maximum stress failure criteria. The difference in failure behaviors among these three failure criteria (i.e. FLC, maximum strain and maximum stress) was compared. The history of failure evolution and potential damage status of typical specimens were further analyzed through the FE model. The results indicated that the new FLC failure criteria can be used for the failure assessment in CFRPP structures. This study is anticipated to provide a guideline for further investigation into failure mechanism and failure criteria of thermoplastic composites under different service conditions.

Weibel, J-B, Patten, T & Vincze, M 2020, 'Addressing the Sim2Real Gap in Robotic 3-D Object Classification', IEEE Robotics and Automation Letters, vol. 5, no. 2, pp. 407-413.
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Williams, P, Kirby, R & Hill, J 2020, 'Mode matching in axisymmetric fluid-filled pipes: Scattering by a flange', The Journal of the Acoustical Society of America, vol. 147, no. 6, pp. 4202-4213.
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Long range ultrasonic testing of pipelines sends an ultrasonic wave along a pipe wall and then detects scattering from defects present. It is well known that scattering by pipe fixtures and fittings, such as a flange, can cause distortion and interfere with the ability to identify defects. This article develops a theoretical model to investigate scattering from a flange in a fluid-filled pipe with elastic walls. Mode matching is used as this is a computationally efficient way to examine long lengths of pipe and for enforcing the appropriate axial continuity conditions over area discontinuities. A recent article presented a mode matching approach for a similar problem, and it is demonstrated here that a re-casting of the equations is necessary to ensure all of the appropriate matching conditions are enforced. Mode matching predictions are also compared with an alternative point collocation approach in order to provide an independent benchmark. Excellent agreement between mode matching and point collocation is demonstrated, and reflection and transmission coefficients are generated in order to show the resonant behaviour of a flange and illustrate that its influence is significant and strongly frequency dependent.

Wu, L, Falque, R, Perez-Puchalt, V, Liu, L, Pietroni, N & Vidal-Calleja, TA 2020, 'Skeleton-Based Conditionally Independent Gaussian Process Implicit Surfaces for Fusion in Sparse to Dense 3D Reconstruction.', IEEE Robotics Autom. Lett., vol. 5, no. 2, pp. 1532-1539.
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© 2016 IEEE. 3D object reconstructions obtained from 2D or 3D cameras are typically noisy. Probabilistic algorithms are suitable for information fusion and can deal with noise robustly. Consequently, these algorithms can be useful for accurate surface reconstruction. This paper presents an approach to estimate a probabilistic representation of the implicit surface of 3D objects. One of the contributions of the paper is the pipeline for generating an accurate reconstruction, given a set of sparse points that are close to the surface and a dense noisy point cloud. A novel submapping method following the topology of the object is proposed to generate conditional independent Gaussian Process Implicit Surfaces. This allows inference and fusion mechanisms to be performed in parallel followed by information propagation through the submaps. Large datasets can efficiently be processed by the proposed pipeline producing not only a surface but also the uncertainty information of the reconstruction. We evaluate the performance of our algorithm using simulated and real datasets.

Xiao, T, Halkon, B, Zhao, S & Qiu, X 2020, 'A remote acoustic sensing apparatus based on a laser Doppler vibrometer'.

Xiao, T, Qiu, X & Halkon, B 2020, 'Ultra-broadband local active noise control with remote acoustic sensing', Scientific Reports, vol. 10, no. 1, p. 20784.
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AbstractOne enduring challenge for controlling high frequency sound in local active noise control (ANC) systems is to obtain the acoustic signal at the specific location to be controlled. In some applications such as in ANC headrest systems, it is not practical to install error microphones in a person’s ears to provide the user a quiet or optimally acoustically controlled environment. Many virtual error sensing approaches have been proposed to estimate the acoustic signal remotely with the current state-of-the-art method using an array of four microphones and a head tracking system to yield sound reduction up to 1 kHz for a single sound source. In the work reported in this paper, a novel approach of incorporating remote acoustic sensing using a laser Doppler vibrometer into an ANC headrest system is investigated. In this “virtual ANC headphone” system, a lightweight retro-reflective membrane pick-up is mounted in each synthetic ear of a head and torso simulator to determine the sound in the ear in real-time with minimal invasiveness. The membrane design and the effects of its location on the system performance are explored, the noise spectra in the ears without and with ANC for a variety of relevant primary sound fields are reported, and the performance of the system during head movements is demonstrated. The test results show that at least 10 dB sound attenuation can be realised in the ears over an extended frequency range (from 500 Hz to 6 kHz) under a complex sound field and for several common types of synthesised environmental noise, even in the presence of head motion.

Xiao, T, Qiu, X & Halkon, B 2020, 'Ultra-broadband local active noise control with remote acoustic sensing.', Scientific reports, vol. 10, no. 1.
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One enduring challenge for controlling high frequency sound in local active noise control (ANC) systems is to obtain the acoustic signal at the specific location to be controlled. In some applications such as in ANC headrest systems, it is not practical to install error microphones in a person's ears to provide the user a quiet or optimally acoustically controlled environment. Many virtual error sensing approaches have been proposed to estimate the acoustic signal remotely with the current state-of-the-art method using an array of four microphones and a head tracking system to yield sound reduction up to 1 kHz for a single sound source. In the work reported in this paper, a novel approach of incorporating remote acoustic sensing using a laser Doppler vibrometer into an ANC headrest system is investigated. In this "virtual ANC headphone" system, a lightweight retro-reflective membrane pick-up is mounted in each synthetic ear of a head and torso simulator to determine the sound in the ear in real-time with minimal invasiveness. The membrane design and the effects of its location on the system performance are explored, the noise spectra in the ears without and with ANC for a variety of relevant primary sound fields are reported, and the performance of the system during head movements is demonstrated. The test results show that at least 10 dB sound attenuation can be realised in the ears over an extended frequency range (from 500 Hz to 6 kHz) under a complex sound field and for several common types of synthesised environmental noise, even in the presence of head motion.

Xue, H, Luo, Z, Brown, T & Beier, S 2020, 'Design of Self-Expanding Auxetic Stents Using Topology Optimization', Frontiers in Bioengineering and Biotechnology, vol. 8, p. 736.
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Implanting stents is the most efficient and minimally invasive technique for treating coronary artery diseases, but the risks of stent thrombosis (ST) and in-stent restenosis (IRS) hamper the healing process. There have been a variety of stents in market but dominated by ad hoc design motifs. A systematic design method that can enhance deliverability, safety and efficacy is still in demand. Most existing designs are focused on patient and biological factors, while the mechanical failures related to stenting architectures, e.g., inadequate stent expansion, stent fracture, stent malapposition and foreshortening, are often underestimated. With regard to these issues, the self-expanding (SE) stents may perform better than balloon-expandable (BE) stents, but the SE stents are not popular in clinic practice due to poor deliverability, placement accuracy, and precise match of the stent size and shape to the vessel. This paper addresses the importance between stent structures and clinic outcomes in the treatment of coronary artery disease. First, a concurrent topological optimization method will be developed to systematically find the best material distribution within the design domain. An extended parametric level set method with shell elements is proposed in the topology optimization to ensure the accuracy and efficiency of computations. Second, the auxetic metamaterial with negative Poisson's ratio is introduced into the self-expanding stents. Auxetics can enhance mechanical properties of structures, e.g., fracture toughness, indentation and shear resistance and vibration energy absorption, which will help resolve the drawbacks due to the mechanical failures. Final, the optimized SE stent is numerically validated with the commercial software ANSYS and then prototyped using additive manufacturing techniques. Topological optimization gives a rare opportunity to exploiting the unique advantages of additive manufacturing. Hence, the topologically optimized auxet...

Ye, K, Ji, J & Han, S 2020, 'Semi-active noise control for a hermetic digital scroll compressor', Journal of Low Frequency Noise, Vibration and Active Control, vol. 39, no. 4, pp. 1204-1215.
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Hermetic digital scroll compressor has been widely used as a small-scale organic Rankine cycle application in the heating, ventilation, and air conditioning systems. A clunking noise issue is recently found in an air conditioning outdoor unit, and the main cause of the noise is experimentally identified to be the impact of the scrolls in the compressor unit during the switching process. The semi-active control methods are thus designed to greatly reduce the noise level by using additional valves to adjust the pressure changing rate within the modulation chamber. The response time for the impact of the scrolls can then be controlled by the added valves. The additional release valve with a smaller diameter pipe parallel to the main valve is tested firstly for its performance. Slower flow rate is produced and the pipe can extend the response time and decrease the speed of the impact process by reducing the pressure changing rate. The use of a discharge valve is also tested for controlling the pressure changing rate inside the chamber. The discharge valve with an opposite effect to the release valve is found useful for solving the noise issue. Both noise and vibration results confirm that the impact noise in the frequency range of interest can be reduced by using the proposed semi-active control methods.

Ye, K, Ji, JC & Brown, T 2020, 'Design of a quasi-zero stiffness isolation system for supporting different loads', Journal of Sound and Vibration, vol. 471, pp. 115198-115198.
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© 2020 Elsevier Ltd The quasi-zero stiffness (QZS) vibration isolation system using negative stiffness structure can generally increase the workable frequency range and improve the isolation performance, in comparison with a linear vibration isolator. However, most of the QZS isolation systems are sensitive to the loads applied for achieving effective isolation. A QZS system designed for a certain load supported cannot provide an effective vibration isolation for another load, as the designed QZS region is not suitable for the new load and thus it no longer demonstrates the anticipated isolation performance. This paper presents an optimized structure for the QZS system to adaptively respond to different loads based on a cam-roller mechanism. Innovation of the present design is the capacity of supporting multi-load levels to isolate the vibrations in low frequency range. Frictional force occurring on the cam-roller contact is considered in the modelling to represent practical application situations. Both static and dynamic responses are theoretically studied for the QZS characteristic and isolation performance. A prototype of the proposed QZS structure is designed, fabricated and tested to verify its isolation performance. Experimental results demonstrate an excellent agreement with the theoretical results, which promotes the implementation of the proposed design into engineering applications.

Yin, H, Wang, Y, Ding, X, Tang, L, Huang, S & Xiong, R 2020, '3D LiDAR-Based Global Localization Using Siamese Neural Network', IEEE Transactions on Intelligent Transportation Systems, vol. 21, no. 4, pp. 1380-1392.
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Yin, S, Wen, G, Ji, J & Xu, H 2020, 'Novel two-parameter dynamics of impact oscillators near degenerate grazing points', International Journal of Non-Linear Mechanics, vol. 120, pp. 103403-103403.
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© 2020 Elsevier Ltd Following the previous work on the degenerate grazing bifurcations of impact oscillators, this paper aims to explore novel two-parameter dynamics near the degenerate grazing points using GPU parallel computing technology. By using the technology, a further understanding of the near-grazing dynamics can be developed for impact oscillators. Three main indicators, i.e., the largest Lyapunov exponent, number of excitation periods and number of impacts, are calculated for each grid of the two-parameter plane chosen. Based on these indicators, the dynamic response in the vicinity of degenerate grazing points can be characterized and more dynamic behaviors than the published results can be discovered. Phenomena of coexisting attractors and chaotic transitions including crisis are also discussed. The single and two degree-of-freedom impact oscillators are selected as illustrative examples to demonstrate the results.

Yoo, C, Lensgraf, S, Fitch, R, Clemon, LM & Mettu, RR 2020, 'Toward Optimal FDM Toolpath Planning with Monte Carlo Tree Search.', CoRR, vol. abs/2002.01631, pp. 4037-4043.

Yu, H, Lu, W, Han, Y, Liu, D & Zhang, M 2020, 'Heterogeneous Dimensionality Reduction for Efficient Motion Planning in High-Dimensional Spaces', IEEE Access, vol. 8, pp. 42619-42632.
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© 2013 IEEE. Increasing the dimensionality of the configuration space quickly makes trajectory planning computationally intractable. This paper presents an efficient motion planning approach that exploits the heterogeneous low-dimensional structures of a given planning problem. These heterogeneous structures are obtained via a Dirichlet process (DP) mixture model and together cover the entire configuration space, resulting in more dimensionality reduction than single-structure approaches from the existing literature. Then, a unified low-dimensional trajectory optimization problem is formulated based on the obtained heterogeneous structures and a proposed transversality condition which is further solved via SQP in our implementation. The positive results demonstrate the feasibility and efficiency of our trajectory planning approach on an autonomous underwater vehicle (AUV) and a high-dimensional intervention autonomous underwater vehicle (I-AUV) in cluttered 3D environments.

Yu, J, Ji, J, Miao, Z & Zhou, J 2020, 'Region-based flocking control for networked robotic systems with communication delays', European Journal of Control, vol. 52, pp. 78-86.
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© 2019 European Control Association Based on a self-tuning adaptive control gain technique, this paper proposes a novel adaptive controller to implement the region-based flocking control for the networked robotic systems with communication delays. It is shown that under the proposed control strategy, all the robots can always reach into the objective region, realize velocity matching and ensure collision avoidance, if the network topology graph is connected under certain initial position conditions. Some simulation results are provided to illustrate the effectiveness and robustness of the proposed novel controller.

Yu, JW, Zhang, XH, Ji, JC, Tian, JY & Zhou, J 2020, 'Region-Reaching Control of a Flexible-Joint Manipulator', Journal of Dynamic Systems, Measurement, and Control, vol. 142, no. 11.
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Abstract This paper addresses the region-reaching control problem for a flexible-joint robotic manipulator which is formulated by Lagrangian dynamics. An adaptive control scheme is proposed for the manipulator system having two constrained regions which are constructed by selecting appropriate objective functions. The two joints of the flexible-joint manipulator can be, respectively, confined in different regions, and this gives more flexibility than the traditional fixed-point tracking control. By performing a straightforward Lyapunov stability analysis, a simple control algorithm is established to provide a solution for the region-reaching control problem. Finally, numerical simulations are given to validate the theoretical results.

Zhang, X, Hu, W, Pei, L, Zhao, S, Zhang, C & Wang, Z 2020, 'In(NO₃)₃ catalyzed curing reaction of benzoxazine', High Performance Polymers, vol. 32, no. 6, pp. 702-709.
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Benzoxazine is a new kind of thermoset resin with excellent properties, but it suffers from high curing temperature and low char yield in the presence of catalyst without halogen. In(NO3)3 was herein used for the first time to efficiently catalyze the curing reaction of benzoxazine and to elevate the char yield at 800°C. The reaction of benzoxazine was catalyzed by In(NO3)3 after stirring at 35°C for 300 min, and the initial curing temperature decreased to 151°C. Polybenzoxazine/In(NO3)3 showed higher thermal stability and char yield at 800°C (increased by 7.5%) compared with those of polybenzoxazine. The possible pathway of coordination bonding between In3+ and benzoxazine was proposed. In the cross-linking process, two different structures, that is, the N, O-acetal bridge structure and arylamine Mannich bridge structure formed at 35°C, both existed, which ultimately affected the thermal stability of the cured product.

Zhang, Y, Ji, J & Ma, B 2020, 'Fault diagnosis of reciprocating compressor using a novel ensemble empirical mode decomposition-convolutional deep belief network', Measurement, vol. 156, pp. 107619-107619.
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© 2020 Elsevier Ltd In order to denoise the raw signal and fuse multiple sources of information for the fault diagnosis of reciprocating compressor, this paper proposes a novel convolutional deep belief network-based method and employs a novel framework fusing multi-source information to improve the performance of fault diagnosis. Firstly, signals from different sensors of the RC are input into an auto-denoising network, namely, ensemble empirical model decomposition-convolutional deep belief network, to denoise the signal and to extract more robust features by the unsupervised learning. Secondly, the extracted features of each source are input into multiple Gaussian process classifiers which are adopted as the members of probabilistic committee machine (PCM) to calculate the probabilities that each fault occurs. Finally, these probabilities are combined with an optimized weight to make a committee decision on fault type. The proposed method combines the information from multiple sources and enhances the robustness of fault diagnosis. Data from an industrial plant were collected to verify the proposed method. The obtained results demonstrate that the proposed method can effectively diagnose the RC faults with the accuracy rate of up to 91.89%. Furthermore, a comparison of the proposed method with the other methods illustrates the superiority of the proposed method for the diagnosis of RC faults.

Zhang, Y, Ji, J & Ma, B 2020, 'Reciprocating compressor fault diagnosis using an optimized convolutional deep belief network', Journal of Vibration and Control, vol. 26, no. 17-18, pp. 1538-1548.
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This article proposes an optimized convolutional deep belief network for fault diagnosis of reciprocating compressors. Sparse filtering is first used to compress raw signal into compact time series by refining the most representative information and to reduce the computational burden. Then, the proposed convolutional deep belief network is adopted to learn the unsupervised features of the compressed signal without the need of feature extraction by human effort. To improve the generalization ability of the network, an optimized probabilistic pooling out is proposed in this article to replace the standard one in the pooling layer of the convolutional deep belief network. Finally, the unsupervised features calculated by the optimized convolutional deep belief network are fed as the input of the softmax regression classifier for fault identification. Four types of vibration signals reflecting different operating conditions are collected from the industry to validate the effectiveness of the proposed method. The obtained results demonstrate that the proposed convolutional deep belief network method can achieve a higher classification accuracy rate of up to 91% for fault diagnosis than the traditional methods and accomplish the fault diagnosis of reciprocating compressor effectively.

Zhao, F, Ji, JC, Ye, K & Luo, Q 2020, 'Increase of quasi-zero stiffness region using two pairs of oblique springs', Mechanical Systems and Signal Processing, vol. 144, pp. 106975-106975.
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© 2020 Elsevier Ltd Quasi-zero stiffness (QZS) nonlinear isolation systems have demonstrated better performance than their linear counterparts. However, their optimal performance is achieved only in a small displacement range around the static equilibrium position. Based on the QZS system with one pair of oblique springs, this paper proposes a new limb-like QZS system with two pairs of oblique springs to enlarge the QZS range and thus improve its isolation performance. Two pairs of oblique springs are configured to provide the dynamic stiffness opposite to the vertical spring for generating QZS characteristics. In comparison with the corresponding QZS system with one pair of oblique springs, the proposed QZS system with two pairs of oblique springs can achieve a lower dynamic stiffness in a much wider region around the static equilibrium position. Based on the theoretical analysis, a prototype is designed and fabricated to physically realize the QZS isolation system. Experimental results are found to be in good agreement with the theoretical predictions which also confirm the proposed QZS system has better isolation performance than the corresponding QZS system with one pair of oblique springs. The proposed model can be adopted for isolating low frequency vibrations in practical applications.

Zhao, J, Zhao, L, Huang, S & Wang, Y 2020, '2D Laser SLAM With General Features Represented by Implicit Functions', IEEE Robotics and Automation Letters, vol. 5, no. 3, pp. 4329-4336.
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© 2016 IEEE. The main contribution of this letter is the problem formulation and algorithm framework for 2D laser SLAM with general features represented by implicit functions. Since 2D laser data reflect the distances from the robot to the boundary of objects in the environment, it is natural to use the boundary of the general objects/features within the 2D environment to describe the features. Implicit functions can be used to represent almost arbitrary shapes from simple (e.g. circle, ellipse, line) to complex (e.g. a cross-section of a bunny model), thus it is worth studying implicit-expressed feature in 2D laser SLAM. In this letter, we clearly formulate the SLAM problem with implicit functions as features, with rigorously computed observation covariance matrix to be used in the SLAM objective function and propose a solution framework. Furthermore, we use ellipses and lines as examples to compare the proposed SLAM method with the traditional pre-fit method (represent the feature using its parameters and pre-fit the laser scan to get the fitted parameter as virtual observations). Simulation and experimental results show that our proposed method has a better performance compared with the pre-fit method and other methods, demonstrating the potential of this new SLAM formulation and method.

Zhao, S, Niu, F & Qiu, X 2020, 'Effects of geometric properties of a static pressure tube on its frequency response', The Journal of the Acoustical Society of America, vol. 148, no. 3, pp. 1289-1295.
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Static pressure tubes are widely used to measure the static pressure in turbulent flows. Existing work focuses on the alteration of the static pressure tubes to the flow field. This paper investigates the effects of the geometric properties of a static pressure tube on the frequency response. A theoretical formulation is developed to describe the relationship between the sound pressure inside and outside the tube. The numerical simulation results show that the peaks in the frequency response move to lower frequencies when the tube diameter, tube length, and orifice depth increase and when the orifice diameter decreases. Experiments with a 3D-printed static pressure tube were conducted to verify the analytical results. The proposed model can be used to optimize the static pressure tube in the design stage or to correct the measurement results afterwards instead of cumbersome experimental calibration.

Zhao, S, Pei, L, Li, H, Zhang, X, Hu, W, Zhao, G & Wang, Z 2020, 'Enhanced comprehensive properties of polybenzoxazine via tailored hydrogen-bonds', Polymer, vol. 201, pp. 122647-122647.
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Zhao, Y, Luo, Q, Wu, J, Sui, C, Tong, L, He, X & Wang, C 2020, 'Mechanical properties of helically twisted carbyne fibers', International Journal of Mechanical Sciences, vol. 186, pp. 105823-105823.
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© 2020 Elsevier Ltd Carbyne composed of sp-hybridized carbon atoms is perfectly one-dimensional material, showing superior mechanical properties as a promising building material for nanodevices. Such nanomaterials as carbon nanotube ropes with hierarchical helical structures hold a promise for potential applications. Here, a bottom-up theoretical model is established to investigate the mechanical properties of this kind of novel nanomaterials. The effect of helical structures is revealed by comparing the mechanical properties of carbyne ropes. The dependence of the mechanical properties of materials on the initial helical angles and fiber numbers at different structural levels are examined. Carbyne ropes are found with higher deformation ability and elastic property which can be easily tuned via their microstructural parameters. This work provides inspirations for optimal design of advanced nanomaterials with helical structures.

Zheng, J, Ji, J, Yin, S & Tong, V-C 2020, 'Fatigue life analysis of double-row tapered roller bearing in a modern wind turbine under oscillating external load and speed', Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, vol. 234, no. 15, pp. 3116-3130.
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Fatigue life analysis of roller bearing is usually performed for bearings under constant rotating speed and invariant loading conditions. For the bearings used in offshore floating direct-drive wind turbines, they often experience oscillating motions with varying loading patterns, for which the standard fatigue life analysis is not valid due to the presence of fluctuating loads. This paper presents the fatigue life analysis of a double-row tapered roller bearing under oscillating external load and speed conditions, which is used to support the main shaft of a large modern direct-drive wind turbine. First, a comprehensive quasi-static model of the double-row tapered roller bearing is developed for determining the internal load distribution of rollers. The contact pressure of rollers is then studied using an iterative scheme based on the elastic contact model. After that, the formulation of basic rating life of the double-row tapered roller bearing with oscillating external load and speed is given to calculate the fatigue life. Numerical simulations are carried out to investigate the effects of the oscillating load and speed, angular misalignment, and internal clearance on the fatigue life of the bearing.

Zheng, J, Ji, J, Yin, S & Tong, V-C 2020, 'Internal loads and contact pressure distributions on the main shaft bearing in a modern gearless wind turbine', Tribology International, vol. 141, pp. 105960-105960.
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© 2019 Elsevier Ltd The double-row tapered roller bearing (TRB) widely used to support the main shaft in a modern gearless wind turbine is one of the main components and its faults can lead to the malfunctions and downtime of wind turbines. Over the past decades, some numerical approaches have been proposed for calculating the contact force and pressure distribution of double-row TRBs. Nevertheless, most of the existing studies did not take the angular misalignment between inner and outer rings and the frictional force between the rollers and raceways into account. This paper presents a comprehensive quasi-static model to investigate the internal load and contact pressure distribution in a double-row TRB by considering the angular misalignment, the combined external loads and frictional force. It is found that a small misalignment angle between inner and outer rings can result in a significant change in the magnitude and distribution of the contact force and pressure. The double-row TRB with crowned roller profile exhibits a substantial improvement in contact pressure distribution by eliminating the occurrence of pressure concentration. Moreover, the peak contact pressure can be significantly reduced on the roller with the crowned profile, even if in the case of misaligned bearing. Comparisons of the simulated contact loads and pressure distributions demonstrate the necessity of considering angular misalignment and frictional force in the modelling of large size and heavily loaded double-row TRB.

Zhu, H, Hu, W, Zhao, S, Zhang, X, Pei, L, Zhao, G & Wang, Z 2020, 'Flexible and thermally stable superhydrophobic surface with excellent anti-corrosion behavior', Journal of Materials Science, vol. 55, no. 5, pp. 2215-2225.
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Abbasnejad, B, McGloin, D & Clemon, L 1970, 'A Flexible Hair-Like Laser Induced Graphitic Sensor for Low Flow Rate Sensing Applications', Volume 5: Biomedical and Biotechnology, ASME 2020 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers.
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Abstract Direct low flow sensing is of interest to many applications in medical and biochemical industries. Low flow rate measurement is still challenging, and conventional flow sensors such as hot films, hot wires and Pitot probes are not capable of measuring very low flow rates accurately. In some applications that require flow measurement in a small diameter tubing (e.g. intravenous (IV) infusion), using such sensors also becomes mechanically impractical. Herein, a flexible laser-induced graphitic (LIG) piezoresistive flow sensor has been fabricated in a cost-effective single processing step. The capability of the LIG sensor in very low flow rate measurement has been investigated by embedding the sensor within an intravenous (IV) line. The embedded LIG hair-like sensor was tested at ambient temperature within the IV line at flow rates ranging from 0 m/s to 0.3 m/s (IV infusion free-flow rate). The LIG hair-like sensor presented in this study detects live flow rates of IV infusions with a threshold detection limit as low as 0.02 m/s. Moreover, the deformation of the LIG hair-like sensor that lead to resistance change in response to various flow rates is simulated using COMSOL Multiphysics.

Au, W, Sakaue, T & Liu, D 1970, 'A Model for Optimising the Size of Climbing Robots for Navigating Truss Structures', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Las Vegas, NV, USA.
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Truss structures can be found in many buildings and civil infrastructure such as bridges and towers. But as these architectures age, their maintenance is required to keep them structurally sound. A legged robotic solution capable of climbing these structures for maintenance is sought, but determining the size and shape of such a robot to maximise structure coverage is a challenging task. This paper proposes a model in which the size of a multi-legged robot is optimised for coverage in a truss structure. A detailed representation of a truss structure is presented, which forms the novel framework for constraint modelling. With this framework, the overall truss structure coverage is modelled, given a robot's size and its climbing performance constraints. This is set up as an optimisation problem, such that its solution represents the optimum size of the robot that satisfies all constraints. Three case studies of practical climbing applications are conducted to verify the model. By intuitive analysis of the model's output data, the results show that the model accurately applies these constraints in a variety of truss structures.

Bauer, D, Patten, T & Vincze, M 1970, 'Physical Plausibility of 6D Pose Estimates in Scenes of Static Rigid Objects', Springer International Publishing, pp. 648-662.
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Bem, NFSD, Ruppert, MG, Yong, YK & Fleming, AJ 1970, 'Integrated force and displacement sensing in active microcantilevers for off-resonance tapping mode atomic force microscopy', 2020 International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), 2020 International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), IEEE.
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Best, G & Hollinger, GA 1970, 'Decentralised Self-Organising Maps for Multi-Robot Information Gathering', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE.
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Best, G, Cliff, OM, Patten, T, Mettu, RR & Fitch, R 1970, 'Decentralised Monte Carlo Tree Search for Active Perception', Workshop on the Algorithmic Foundations of Robotics (WAFR), Workshop on the Algorithmic Foundations of Robotics (WAFR), Springer International Publishing, San Francisco, USA, pp. 864-879.
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We propose a decentralised variant of Monte Carlo tree search (MCTS) that is suitable for a variety of tasks in multi-robot active perception. Our algorithm allows each robot to optimise its own individual action space by maintaining a probability distribution over plans in the joint-action space. Robots periodically communicate a compressed form of these search trees, which are used to update the locally-stored joint distributions using an optimisation approach inspired by variational methods. Our method admits any objective function defined over robot actions, assumes intermittent communication, and is anytime. We extend the analysis of the standard MCTS for our algorithm and characterise asymptotic convergence under reasonable assumptions. We evaluate the practical performance of our method for generalised team orienteering and active object recognition using real data, and show that it compares favourably to centralised MCTS even with severely degraded communication. These examples support the relevance of our algorithm for real-world active perception with multi-robot systems.

Brown, M, Dey, S & Tuxworth, G 1970, 'Selection factors determining the hybrid approach: A preliminary study', AMCIS 2020 PROCEEDINGS, Conference of the Association-for-Information-Systems (AMCIS), ASSOC INFORMATION SYSTEMS, ELECTR NETWORK.

Carmichael, M, Khonasty, R, Wilkinson, S & Schork, T 1970, 'The wallbot: A low-cost robot for green wall inspection', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Brisbane, Australia, pp. 1-7.
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The benefits of urban green infrastructure, such as attenuating the urban heat island effect and improving air quality, are widely accepted. Regardless, the uptake of green walls (i.e. vertical gardens) is low due to the high costs relating to maintenance and OH&S. These barriers to adoption may be mitigated by using robotics to inspect and maintain green walls. In this work we present the Wallbot, a robotic system to inspect, monitor and aid in the maintenance of green walls. In its current form the system comprises of affordable off-the-shelf components to keep the system cost low. Preliminary development of the system, results of initial tests and findings are presented. The system offers the chance to reduce OH&S issues and maintenance costs associated with green walls.

Carmichael, MG, Khonasty, R, Aldini, S & Liu, D 1970, 'Human Preferences in Using Damping to Manage Singularities During Physical Human-Robot Collaboration', 2020 IEEE International Conference on Robotics and Automation (ICRA), 2020 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Paris, France, pp. 10184-10190.
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When a robot manipulator approaches a kinematic singular configuration, control strategies need to be employed to ensure safe and robust operation. If this manipulator is being controlled by a human through physical human-robot collaboration, the choice of strategy for handling singularities can have a significant effect on the feelings and impressions of the user. To date the preferences of humans during physical human-robot collaboration regarding strategies for managing kinematic singularities have yet to be thoroughly explored.This work presents an empirical study of a damping-based strategy for handling singularities with regard to the preferences of the human operator. Two different parameters, damping rate and damping asymmetry, are tested using a double-blind A/B pairwise comparison testing protocol. Participants included two cohorts made up of the general public (n=51) and people working within a robotic research centre (n=18). In total 105 individual trials were performed. Results indicate a preference for a faster, asymmetric damping behavior that slows motions towards singularities whilst allowing for faster motions away.

Clemon, L 1970, 'Directed Graphical Model for Real-Time Process Monitoring in Additive Manufacturing', Volume 2A: Advanced Manufacturing, ASME 2020 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers.
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Abstract An important challenge for additive manufacturing and 3D printing processes is accurate and repeatable deposition quality. Current approaches are unable to handle variable process parameters and input material quality. Accurately controlling material properties requires predicting material state changes. This work proposes a model using statistical learning techniques in conjunction with iterative material study to identify and compute the sources of defects and local material properties. The model makes use of the element-by-element fabrication and time-series material changes of additive manufacturing. The deposition of a part is segmented into volume elements, called voxels. Each deposited voxel is treated as an independent sample of the process parameter effects. The time series of deposition is treated as a Markov Chain, with the control parameters and measurable emissions as known quantities. The state of the material is a hidden variable. The hidden variable is approximated using material models and post-fabrication testing results to train the distribution embedded in the Markov Chain. The results indicated that a physics-based material state transition matrix in conjunction with final material properties and time-series of physical emissions can give insight into process variability and control errors. These results have wide ranging implications as a computationally efficient means of iterative process improvement for additive manufacturing, designing new control strategies, and revealing the real-time state of voxels as they are deposited. This approach moves closer to a predictive model that includes current information on the state of the process to update the prediction.

Darwish, A, Halkon, B, Oberst, S, Fitch, R & Rothberg, S 1970, 'CORRECTION OF LASER DOPPLER VIBROMETER MEASUREMENTS AFFECTED BY SENSOR HEAD VIBRATION USING TIME DOMAIN TECHNIQUES', XI International Conference on Structural Dynamics, XI International Conference on Structural Dynamics, EASD, Athens, pp. 4842-4850.
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Despite widespread use in a variety of areas, in-field applications of laser Doppler vibrometers (LDVs) are still somewhat limited due to their inherent sensitivity to vibration of the instrument sensor head itself. Earlier work, briefly reviewed herein, has shown it to be possible to subtract the instrument vibration via a number of means, however, it has been difficult up to now to truly compare the performance of these. This is compounded by the constraint that a frequency domain based approach only holds for stationary vibration signals while, particularly for in-field applications, an approach that is also applicable to transient signals is necessary. This paper therefore describes the development of a novel time domain post-processing based approach for vibrating LDV measurement correction and compares it with the frequency domain counterpart. Results show that, while both techniques offer significant improvements in the corrected LDV signal when compared to a reference accelerometer measurement, the time domain based correction outperforms the frequency domain based method by a factor of eight

Deuse, J, Stankiewicz, L, Zwinkau, R & Weichert, F 1970, 'Automatic Generation of Methods-Time Measurement Analyses for Assembly Tasks from Motion Capture Data Using Convolutional Neuronal Networks - A Proof of Concept', Advances in Intelligent Systems and Computing, Springer International Publishing, pp. 141-150.
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© Springer Nature Switzerland AG 2020. This paper describes the research hypothesis that motion data can be utilized to derive MTM analyses. As a first step, manual assembly tasks are recorded with motion capture systems to generate motion data. These motion data are used as a training data set for an end-to-end deep learning architecture for motion classification. The result of this classification is the assignment of data sequences to corresponding basic motions of MTM-1. The paper also describes the prerequisites for an automatic generation of MTM analyses by considering an adaptation of the original MTM methodology to fit for an automatic approach, the acquisition of motion capture data and the automatic annotation of motion data.

Eager, D & Hayati, H 1970, 'Understanding greyhound race track risk factors', GRV On-Track Veterinarians Conference, GRV On-Track Veterinarians Conference, Melbourne, Australia.

Hadgraft, RG, Francis, B, Fitch, R, Halkon, B & Brown, T 1970, 'Renewing mechanical and mechatronics programs using studios', SEFI 47th Annual Conference: Varietas Delectat... Complexity is the New Normality, Proceedings, SEFI Annual Conference, SEFI, Budapest, Hungary, pp. 511-522.
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In a world of rapid change, engineering programs need to adapt to be relevant. This paper addresses the renewal processes for mechanical and mechatronics engineering programs at a large university of technology. The paper sits within a wider curriculum change movement, including all engineering and IT programs at this university. Several meetings have been held over the last 3 years with both industry panels and with academic staff and students to understand the nature of the problem. Using a design-thinking approach, we have explored: global trends, the nature of engineering work and projects, the capabilities required by engineers, and the kinds of capabilities that graduates need to operate confidently in this new world of work. There is a clear need for graduates to be more operational as they move from study to work. Consequently, a major focus on experiential learning is emerging as the key delivery vehicle for new kinds of graduates including projects, studios, and internships. These forms of learning are supported by ready access to online materials as required. A central thread is personalisation of the student learning experience through learning contracts and portfolios. There has been constant demand for change in engineering education for at least the last 20 years. Making change happen, however, is another matter. We are in the fortunate position at this university to have high level support from the Chancellery and the Dean to move our engineering programs to be more relevant to the future. This paper describes the process for engaging our academics, students and industry supporters in that process and will be of interest to many who are grappling with similar transitions.

Halkon, B, Cheong, I, Visser, G, Walker, P & Oberst, S 1970, 'An experimental assessment of torsional and package vibration in an industrial engine-compressor system', 12th International Conference on Vibrations in Rotating Machinery, Vibrations in Rotating Machinery, CRC Press, Liverpool, pp. 625-639.
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An experimental field vibration measurement campaign was conducted on an engine-compressor system. Torsional vibrations were measured using both a strain-gauge based technique at the engine-compressor coupling and a rotational laser vibrometer at the torsional vibration damper. Package vibration measurements were simultaneously captured using a number of accelerometers mounted at various locations on the engine and compressor casings. Findings from the study include the observation that the coupling/damper dominant order 1.5 torsional vibration level was higher at idle (c14.1 Hz) than at full speed (c19.1 Hz) and that this is likely the result of the coincidence of the first torsional natural frequency (c19-20 Hz); vibration remained within limits. The package vibration observed was in general within limits and displayed the expected behaviour when shaft speeds coincided with structural resonances. Increasing of system load was observed to result in package vibration level increase in the engine but reduction in the compressor and this is suspected to be as a result of the effect of increased damping. Induced cylinder misfire scenarios were shown to lead to higher vibration levels. To the authors’ knowledge, this is the first time that angular displacement, vibratory torque and package vibration have been simultaneously measured, analysed and reported in an industrial context/scenario. It is hoped that this contribution might, therefore, serve as a practical guide to vibration engineers that wish to embark on similar campaigns.

Hall, N, Peng, J, Parnell, J & Wassermann, J 1970, 'Investigation of uniform and non-uniform traffic distribution on road traffic noise prediction for multi-lane roadways', Acoustics 2019, Sound Decisions: Moving Forward with Acoustics - Proceedings of the Annual Conference of the Australian Acoustical Society.
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Road traffic noise prediction is routinely undertaken as part of environmental impact assessments to assist government planning authorities to understand the potential noise impact that could arise from proposed road infrastructure development projects. Typically, road traffic noise models developed in New South Wales detail all lanes of a roadway and assume uniform distribution of traffic volume and vehicle mix across the lanes of each carriageway. In this work, the effects of uniform and non-uniform traffic distribution on road traffic noise prediction for multi-lane roadways are investigated. Models with all lanes detailed are compared to simplified two-lane models for a range of receiver setback distances and shielding arrangements.

Hassan, M, Liu, D & Chen, X 1970, 'Squircular-CPP: A Smooth Coverage Path Planning Algorithm based on Squircular Fitting and Spiral Path', 2020 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2020 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), IEEE, Boston, MA, USA, pp. 1075-1081.
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Coverage path planning (CPP) is essential for applications such as robotic floor cleaning and high-pressure cleaning of surfaces. Smooth CPP algorithms have several benefits including smoother motion of the robot and the reduction of aggressive accelerations and decelerations resulting from sharp turns. In this paper, a novel smooth CPP algorithm is presented which is named Squircular-CPP. This algorithm proposes a squircular shape, which is an intermediate shape between the circle and the square, to fit a target area. Squircular-CPP can also fit a shape between the ellipse and the rectangle. The shape fitting is simple, fast, and analytical and doesn't require a preselection of the shape (i.e., square, circle, ellipse or rectangle). It enables and complements the creation of a smooth spiral path within the fitted shape. Several case studies are presented to demonstrate the effectiveness of the algorithm and to compare it against the popular boustrophedon-based coverage approach and the Deformable Spiral CPP (DSCPP) algorithm.

Hassan, M, Mustafic, D & Liu, D 1970, 'Dec-PPCPP: A Decentralized Predator–Prey-based Approach to Adaptive Coverage Path Planning Amid Moving Obstacles', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Las Vegas, NV, USA, pp. 11732-11739.
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Hauge, E, Bui, A, Rajalingam, J, Karunatilake, N, Hunt, D, Vitanage, D, Dissanayake, G & Valls Miro, J 1970, 'Robotic Pipe Scanning: Intelligent Internal Toolkit for Critical Water Mains'', Ozwater’20 Papers, OzWater'20 Australia's International Water Conference and Exhibition, Australian Water Association, Adelaide, pp. 1-7.
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Sydney Water manages a complex water network that includes 5,000 km of large-diameter critical pipelines. To maintain customer satisfaction and minimise loss of water it is essential to manage leaks, breaks through implementing an effective and efficient preventive maintenance and renewal program. Sydney Water in collaboration with the University of Technology Sydney’s Centre for Autonomous Systems (UTS CAS) has developed two world-leading robotic condition assessment tools. These travel inside a dewatered pipe, providing a full 360° wall thickness scan up to 500m in length. Sydney Water has successfully deployed the tools during main failures. It also expects to apply the technology in planned maintenance inspection interventions.

Heon Lee, JJ, Yoo, C, Anstee, S & Fitch, R 1970, 'Hierarchical Planning in Time-Dependent Flow Fields for Marine Robots', 2020 IEEE International Conference on Robotics and Automation (ICRA), 2020 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Paris, France (Virtual), pp. 885-891.
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We present an efficient approach for finding shortest paths in flow fields that vary as a sequence of flow predictions over time. This approach is applicable to motion planning for slow marine robots that are subject to dynamic ocean currents. Although the problem is NP-hard in general form, we incorporate recent results from the theory of finding shortest paths in time-dependent graphs to construct a polynomial-time algorithm that finds continuous trajectories in time-dependent flow fields. The algorithm has a hierarchical structure where a graph is constructed with time-varying edge costs that are derived from sets of continuous trajectories in the underlying flow field. We show that the continuous algorithm retains the time complexity and path quality properties of the discrete graph solution, and demonstrate its application to surface and underwater vehicles including a traversal along the East Australian Current with an autonomous marine vehicle. Results show that the algorithm performs efficiently in practice and can find paths that adapt to changing ocean currents. These results are significant to marine robotics because they allow for efficient use of time-varying ocean predictions for motion planning.

Hossain, A, Tipper, JL & Wei, D 1970, 'Analysis of a Multi-Material Bone Plate and its Effect on Interfragmentary Strain for Bone Remodeling Processes', Volume 1: Additive Manufacturing; Advanced Materials Manufacturing; Biomanufacturing; Life Cycle Engineering; Manufacturing Equipment and Automation, ASME 2020 15th International Manufacturing Science and Engineering Conference, American Society of Mechanical Engineers.
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Abstract The success of bone repair using an internal fracture fixation technique is critically dependent on the stability and biological process between the fragmented bones. However, the currently used bone plates mainly focus on stability rather than biology of healing, which subsequently (a) results in significant stress-shielding effects and (b) prevents stress from transferring from the bone plate to the bone during the healing process. This study proposes a novel design of a bone plate for the fixation of long fractured bones, which can mitigate these disadvantages to strike a balance between stability and biology. The new multi-material design adopts stainless steel (SS316L) and magnesium alloy (AZ31B) of three thicknesses such as SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B (1mm). The mechanical properties (bending stiffness and moment) of the bone plates were evaluated according to the ASTM: F382-17 standard. Static corrosion tests were conducted in Hank’s Balanced Salt Solution (HBSS) at 37.5 °C. Compared with those of the original (non-corroded) bone plates, the maximum load-carrying capacities of the corroded bone plates decreased from 670 N to 495 N, 891 N to 518 N, and 928 N to 709 N in the case of SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B(1mm), respectively. Digital image correlation was utilized to evaluate the inter-fragmentary strain (IFS) in the physical model of fractured bone plates. The IFS increased from 0.526 to 0.815, 0.484 to 0.784, and 0.455 to 0.533 in the case of SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B (1mm), respectively, when a load of 200 N was applied. An optimized design of the bone plate of SS316L and AZ31B for granulation tissue formation based on Perren’s theory and IFS was successfully proposed.

Inkermann, D, Gürtler, M & Seegrün, A 1970, 'RECAP – A FRAMEWORK TO SUPPORT STRUCTURED REFLECTION IN ENGINEERING PROJECTS', Proceedings of the Design Society: DESIGN Conference, 16th International Design Conference - DESIGN 2020, Cambridge University Press (CUP), Dubrovnik, Croatia - Online, pp. 597-606.
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AbstractReflection is understood as an integral part of designing and design processes. Despite the high relevance and an ongoing discussion about agile engineering, we found that reflection is rarley established in industrial practice. There is a need for an approach structuring the wide range of levels, stakeholders, objects and timing of reflections. The introduced RECAP framework is an important step towards a guideline (heuristic) for reflection in engineering projects. Based on the four dimensions objectives, stakeholders, objects, and processes it supports structured planning of reflection.

Jayasuriya, M, Arukgoda, J, Ranasinghe, R & Dissanayake, G 1970, 'Localising PMDs through CNN Based Perception of Urban Streets.', ICRA, IEEE International Conference on Robotics and Automation, IEEE, Paris, France, pp. 6454-6460.
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The main contribution of this paper is a novel Extended Kalman Filter (EKF) based localisation scheme that fuses two complementary approaches to outdoor vision based localisation. This EKF is aided by a front end consisting of two Convolutional Neural Networks (CNNs) that provide the necessary perceptual information from camera images. The first approach involves a CNN based extraction of information corresponding to artefacts such as curbs, lane markings, and manhole covers to localise on a vector distance transform representation of a binary image of these ground surface boundaries. The second approach involves a CNN based detection of common environmental landmarks such as tree trunks and light poles, which are represented as point features on a sparse map. Utilising CNNs to obtain higher level information about the environment enables this framework to avoid the typical pitfalls of common vision based approaches that use low level hand crafted features for localisation. The EKF framework makes it possible to deal with false positives and missed detections that are inevitable in a practical CNN, to produce a location estimate together with its associated uncertainty. Experiments using a Personal Mobility Device (PMD) driven in typical suburban streets are presented to demonstrate the effectiveness of the proposed localiser.

Jayasuriya, M, Arukgoda, J, Ranasinghe, R & Dissanayake, G 1970, 'Towards Adapting Autonomous Vehicle Technology for the Improvement of Personal Mobility Devices', 2020 5th International Conference on Innovative Technologies in Intelligent Systems and Industrial Applications (CITISIA), 2020 5th International Conference on Innovative Technologies in Intelligent Systems and Industrial Applications (CITISIA), IEEE, Sydney, Australia.
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Personal Mobility Devices (PMDs) incorporated with autonomy, have great potential in becoming an essential building block of smart transportation infrastructures of the future. However, autonomous vehicle technologies currently employ large and expensive sensors / computers and resource intensive algorithms, which are not suitable for low cost, small form factor PMDs. In this paper, a mobility scooter is retrofitted with a low cost sensing and computing package with the aim of achieving autonomous driving capability. As a first step, a novel, real time, low cost and resource efficient vision only localisation framework based on Convolutional Neural Network (CNN) oriented feature extraction and extended Kalman filter oriented state estimation is presented. Real world experiments in a suburban environment are presented to demonstrate the effectiveness of the proposed localisation framework.

Jayasuriya, M, Ranasinghe, R & Dissanayake, G 1970, 'Active Perception for Outdoor Localisation with an Omnidirectional Camera.', IROS, 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Las Vegas, NV, USA, pp. 4567-4574.
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This paper presents a novel localisation framework based on an omnidirectional camera, targeted at outdoor urban environments. Bearing only information to persistent and easily observable high-level semantic landmarks (such as lamp-posts, street-signs and trees) are perceived using a Convolutional Neural Network (CNN). The framework utilises an information theoretic strategy to decide the best viewpoint to serve as an input to the CNN instead of the full 360° coverage offered by an omnidirectional camera, in order to leverage the advantage of having a higher field of view without compromising on performance. Environmental landmark observations are supplemented with observations to ground surface boundaries corresponding to high-level features such as manhole covers, pavement edges and lane markings extracted from a second CNN. Localisation is carried out in an Extended Kalman Filter (EKF) framework using a sparse 2D map of the environmental landmarks and Vector Distance Transform (VDT) based representation of the ground surface boundaries. This is in contrast to traditional vision only localisation systems that have to carry out Visual Odometry (VO) or Simultaneous Localisation and Mapping (SLAM), since low level features (such as SIFT, SURF, ORB) do not persist over long time frames due to radical appearance changes (illumination, occlusions etc) and dynamic objects. As the proposed framework relies on highlevel persistent semantic features of the environment, it offers an opportunity to carry out localisation on a prebuilt map, which is significantly more resource efficient and robust. Experiments using a Personal Mobility Device (PMD) driven in a representative urban environment are presented to demonstrate and evaluate the effectiveness of the proposed localiser against relevant state of the art techniques.

Khosoussi, K, Sukhatme, GS, Huang, S & Dissanayake, G 1970, 'Designing Sparse Reliable Pose-Graph SLAM: A Graph-Theoretic Approach', International Workshop on the Algorithmic Foundations of Robotics, International Workshop on the Algorithmic Foundations of Robotics, pp. 17-32.
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In this paper, we aim to design sparse D-optimal (determinantoptimal) pose-graph SLAM problems through the synthesis of sparse graphs with the maximum weighted number of spanning trees. Characterizing graphs with the maximum number of spanning trees is an open problem in general. To tackle this problem, several new theoretical results are established in this paper, including the monotone log-submodularity of the weighted number of spanning trees. By exploiting these structures, we design a complementary pair of near-optimal efficient approximation algorithms with provable guarantees. Our theoretical results are validated using random graphs and a publicly available pose-graph SLAM dataset.

Kiss, SH, To, KYC, Yoo, C, Fitch, R & Alempijevic, A 1970, 'Minimally Invasive Social Navigation', Australasian Conference on Robotics and Automation 2019, Australasian Conference on Robotics and Automation, ARAA, Adelaide, Australia, pp. 1-7.
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Integrating mobile robots into human society involves the fundamental problemof navigation in crowds. This problem has been studied by considering thebehaviour of humans at the level of individuals, but this representation limitsthe computational efficiency of motion planning algorithms. We explore the ideaof representing a crowd as a flow field, and propose a formal definition ofpath quality based on the concept of invasiveness; a robot should attempt tonavigate in a way that is minimally invasive to humans in its environment. Wedevelop an algorithmic framework for path planning based on this definition andpresent experimental results that indicate its effectiveness. These resultsopen new algorithmic questions motivated by the flow field representation ofcrowds and are a necessary step on the path to end-to-end implementations.

Lammers, T, Sick, N & Kandlbinder, P 1970, 'Management Consulting Techniques in Engineering Education – The Case of Operations Engineering', https://www.aaee2020.com.au/wp-content/uploads/2020/11/AAEE2020_paper_158.pdf, Australasian Association of Engineering Education, AAEE, Sydney, pp. 1-9.
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There is an increasing need for engineering students to learn how to market themselves as professionals in globalised and competitive environments. When it comes to postgraduate education, students seek to build on their existing work experience and develop theirmanagement and leadership skills to complement their engineering knowledge. The collaborative nature of engineering work suggests that increased engagement in university engineering education will only come from the introduction of activities connected to professional practice.A solution to the challenge of learning in interdisciplinary, socio-technical subjects within engineering can be found by looking at the collaborative professional practice of interdisciplinary professions such as management consulting. In this article, we explore how an activity that has proven successful in engaging corporate stakeholders in a management consulting context, can be adapted in a management subject aimed at engineering students. Based on requirements identified from literature and student feedback, we tailor and implement a shift-and-share activity in the postgraduate subject Operations Engineering, highlighting the potential for consulting activities to contribute to the students’ learning experience. We also measure its success by evaluating the students’ work output and asking the students about the extent to which the activity contributed to achieving those requirements in a short survey. Our study confirms that management consulting techniques can be a source for inspiration when it comes to new activities and lays the foundation for the transfer of other activities in line with case-specific requirements. Our paper highlights a practical case example of how consulting techniques can be appropriately adapted from a corporate to an academic learning environment in a way that aligns with both institutional and individual learning goals. In this context, the paper provides guidance on how to successfull...

Le, DT, Sutjipto, S, Lai, Y & Paul, G 1970, 'Intuitive Virtual Reality based Control of a Real-world Mobile Manipulator', 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), IEEE, Shenzhen, China.
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This paper presents an integration of Virtual Reality (VR) interfaces with the control system of a real-world mobile manipulator, ultimately facilitating a natural and intuitive method for human-robot interaction. VR’s ability to track movements in 3D space and translate performed motions provide an intuitive platform for users to explore and interact with the virtual environment. Coupled with intuitive controls, such as grabbing and pointing, the VR platform provides a compelling advantage that can be used to solve limitations of traditional remote robot teleoperation methods.This paper summarises the system implemented, which includes a simulation of the robot in Unity3d, as well as analyses critical results of accuracy and performance, from experiments with users of various experience levels. The method used for measuring accuracy with a simulated robot presented a utilitarian validation for contrasting the difference between 2D and VR 3D interfaces. Users’ performance and experience under various levels of control latency, which is a crucial factor in remote online robot control, were also measured.

Le, K, To, A, Leighton, B, Hassan, M & Liu, D 1970, 'The SPIR: An Autonomous Underwater Robot for Bridge Pile Cleaning and Condition Assessment', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, pp. 1725-1731.
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Lee, C, Best, G & Hollinger, GA 1970, 'Optimal Deployment of Multiple Passenger Robots using Sequential Stochastic Assignment', RSS Workshop on Heterogeneous Multi-Robot Task Allocation and Coordination.

Liu, L, Zhang, T, Liu, Y, Leighton, B, Zhao, L, Huang, S & Dissanayake, G 1970, 'Parallax Bundle Adjustment on Manifold with Improved Global Initialization', Springer Proceedings in Advanced Robotics (SPAR), International Workshop on the Algorithmic Foundations of Robotics, Springer International Publishing, Mérida, México, pp. 621-638.
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In this paper we present a novel extension to the parallax feature based bundle adjustment (BA). We take parallax BA into a manifold form (PMBA) along with an observation-ray based objective function. This formulation faithfully mimics the projective nature in a camera’s image formation, resulting in a stable optimization configuration robust to low-parallax features. Hence it allows use of fast Dogleg optimization algorithm, instead of the usual Levenberg Marquardt. This is particularly useful in urban SLAM in which diverse outdoor environments and collinear motion modes are prevalent. Capitalizing on these properties, we propose a global initialization scheme in which PMBA is simplified into a pose-graph problem. We show that near-optimal solution can be achieved under low-noise conditions. With simulation and a series of challenging publicly available real datasets, we demonstrate PMBA’s superior convergence performance in comparison to other BA methods. We also demonstrate, with the “Bundle Adjustment in the Large” datasets, that our global initialization process successfully bootstrap the full BA in mapping many sequential or out-of-order urban scenes.

Maleki, B, Alempijevic, A & Vidal-Calleja, T 1970, 'Continuous Optimization Framework for Depth Sensor Viewpoint Selection', Workshop on the Algorithmic Foundations of Robotics, Workshop on the Algorithmic Foundations of Robotics, Springer International Publishing, Merida, Mexico, pp. 357-372.
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Distinguishing differences between areas represented with point cloud data is generally approached by choosing a optimal viewpoint. The most informative view of a scene ultimately enables to have the optimal coverage over distinct points both locally and globally while accounting for the distance to the foci of attention. Measures of surface saliency, related to curvature inconsistency, extenuate differences in shape and are coupled with viewpoint selection approaches. As there is no analytical solution for optimal viewpoint selection, candidate viewpoints are generally discretely sampled and evaluated for information and require (near) exhaustive combinatorial searches. We present a consolidated optimization framework for optimal viewpoint selection with a continuous cost function and analytically derived Jacobian that incorporates view angle, vertex normals and measures of task related surface information relative to viewpoint. We provide a mechanism in the cost function to incorporate sensor attributes such as operating range, field of view and angular resolution. The framework is evaluated as competing favorably with the state-of-the-art approaches to viewpoint selection while significantly reducing the number of viewpoints to be evaluated in the process.

Mehami, J, Vidal-Calleja, T & Alempijevic, A 1970, 'Observability driven Multi-modal Line-scan Camera Calibration', 2020 IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems (MFI), 2020 IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems (MFI), IEEE, Karlsruhe, Germany, pp. 285-290.
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© 2020 IEEE. Multi-modal sensors such as hyperspectral line-scan and frame cameras can be incorporated into a single camera system, enabling individual sensor limitations to be compensated. Calibration of such systems is crucial to ensure data from one modality can be related to the other. The best known approach is to capture multiple measurements of a known planar pattern, which are then used to optimize calibration parameters through non-linear least squares. The confidence in the optimized parameters is dependent on the measurements, which are contaminated by noise due to sensor hardware. Understanding how this noise transfers through the calibration is essential, especially when dealing with line-scan cameras that rely on measurements to extract feature points. This paper adopts a maximum likelihood estimation method for propagating measurement noise through the calibration, such that the optimized parameters are associated with an estimate of uncertainty. The uncertainty enables development of an active calibration algorithm, which uses observability to selectively choose images that improve parameter estimation. The algorithm is tested in both simulation and hardware, then compared to a naive approach that uses all images to calibrate. The simulation results for the algorithm show a drop of 26.4% in the total normalized error and 46.8% in the covariance trace. Results from the hardware experiments also show a decrease in the covariance trace, demonstrating the importance of selecting good measurements for parameter estimation.

Munasinghe, N & Paul, G 1970, 'Integrated 3-D printable temperature sensor for advanced manufacturing', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Queensland, Australia.
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As technology continues to develop at a rapid pace, the world progresses towards the fourth industrial revolution, Industry 4.0, with advancements in automation and machine intelligence, as well as manufacturing breakthroughs leading to more efficient and advanced methods. Additive manufacturing (AM), also known as 3D printing, is a type of manufacturing method that has experienced great development and has revolutionised end-product manufacturing. The authors are involved in a project to develop a large-scale industrial 3D printer to print equipment called a Gravity Separation Spiral (GSS), and in an effort to make the equipment “smart”, sensors need to be embedded inside to monitor the operating conditions remotely. This paper presents a temperature sensor able to be printed by a multi-material 3D printer, into 3D printed equipment. In this method, a conductive carbon-based filament has been used to print temperature-sensitive traces inside a Polylactic Acid (PLA) base. The printed sensor was temperature tested in a controlled environment using a programmable heat pad, and the change in resistance has been measured as a voltage change using a data acquisition device. Tests were conducted within in the expected operating range, between 25 ℃ and 36 ℃, and the absolute temperature error was found to be less than ±2 ℃.

Munasinghe, N & Paul, G 1970, 'Path Planning for Robot Based Radial Advanced Manufacturing Using Print Space Sampling', 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), IEEE, Shenzhen, China.
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The world is embracing the fourth industrial revolution, Industry 4.0, which is enabling businesses to improve efficiency and optimise operations. The authors are part of a team that is researching and developing a large-scale industrial 3D printer to print smart, bespoke equipment called Gravity Separation Spirals (GSS). GSS are used in mining to separate minerals from the slurry. The printer under development employs two industrial robot arms mounted on vertical rails and the print direction is around a vertical rotating column in a radial direction. This paper presents a cost-based path planning method using print-space sampling to optimise distance error and manipulability during a printhead’s radial path as it travels outwards from the central column. Manipulability, distance error and rotation error have been calculated for each sampled point and a weighted cost function has been used to determine the optimal path. Simulated results show that this method reduces the instances of print failure and improves the overall manipulability of the robot during printing.

Nerse, C & Wang, S 1970, 'Vibroacoustic characteristics of a damped box-type structure', Proceedings of 2020 International Congress on Noise Control Engineering, INTER-NOISE 2020.
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In industrial applications, rigid-walled cavities that are enclosed by flexible panels can be commonly encountered. Owing to the coupling of the velocity of the panel with the air pressure in the enclosure, noise and vibration in- and out of- the system is amplified. Such problems are frequently alleviated by passive vibration control, where damping treatments are effective in mid and high frequencies. It has been shown that when such treatments are applied nonproportionally, not only the vibration of the panel, but also the radiated sound pressure from the panel can be reduced, while limiting the mass increase. In this study, the governing relation for this phenomenon is expressed by using the uncoupled modal parameters of the panel and cavity. Complex modes that arise from nonproportionally damped systems are shown to be closely linked to optimal damping characteristics. We further show that the coupling strength between the cavity modes and panel modes are dependent on the spatial distribution of the damping. A damping layer topology optimization problem is formulated to demonstrate the interconnectedness of the modal parameters with optimal damping layer layout.

Neuberger, B, Patten, T, Park, K & Vincze, M 1970, 'Self-initialized Visual Servoing for Accurate End-effector Positioning', 2020 6th International Conference on Control, Automation and Robotics (ICCAR), 2020 6th International Conference on Control, Automation and Robotics (ICCAR), IEEE.
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Nguyen, DDK, Lai, Y, Sutjipto, S & Paul, G 1970, 'Hybrid Multi-Robot System for Drilling and Blasting Automation', 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), IEEE, Shenzhen, China.
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Multi-robot systems possess the potential of becoming the next generation of robots in the mining industry due to their robustness and scalability. However, they present challenges for the system to efficiently allocate tasks to each robot and allow them to navigate toward their targets safely. This paper introduces a hybrid approach method for a multi-robot system, alongside with a case study in drilling and blasting automation. A Centralized Control Unit delegates tasks and information among the robots in the system, each equipped with a decentralized motion planner that supports cooperative inter- robot collision avoidance. The proposed system inherits the advantage of a centralized multi-robot system in providing a time-wise optimal solution; while also possessing the computational benefit and scalability of a decentralized system. Simulations were conducted to validate the proposed method and discuss insights into the efficacy and performance of the proposed method.

Park, K, Patten, T & Vincze, M 1970, 'Neural Object Learning for 6D Pose Estimation Using a Few Cluttered Images'.
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Recent methods for 6D pose estimation of objects assume either textured 3Dmodels or real images that cover the entire range of target poses. However, itis difficult to obtain textured 3D models and annotate the poses of objects inreal scenarios. This paper proposes a method, Neural Object Learning (NOL),that creates synthetic images of objects in arbitrary poses by combining only afew observations from cluttered images. A novel refinement step is proposed toalign inaccurate poses of objects in source images, which results in betterquality images. Evaluations performed on two public datasets show that therendered images created by NOL lead to state-of-the-art performance incomparison to methods that use 13 times the number of real images. Evaluationson our new dataset show multiple objects can be trained and recognizedsimultaneously using a sequence of a fixed scene.

Parnell, J & Peng, J 1970, 'The relevance of the 2018 WHO Noise guidelines to Australasian road traffic noise objectives', Acoustics 2019, Sound Decisions: Moving Forward with Acoustics - Proceedings of the Annual Conference of the Australian Acoustical Society.
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Road traffic noise criteria are generally established by regulators with reference to exposure-response relationships. The release of the World Health Organisation (WHO) Noise Guidelines for the European Region in 2018 therefore had global relevance as it purported to present the most contemporary guidance on road traffic noise impacts. Consistent with European Union reporting requirements, the day-evening-night composite noise metric was referenced. In order to understand the implications of this WHO document on policies across Australasia it is necessary to undertake comparisons using a common noise descriptor. There are a range of noise metrics in use across the jurisdictions, however currently there is no robust process of converting the local noise metrics to the day-evening-night composite noise metric This paper uses a large data set of New South Wales (NSW) road traffic noise measurements collected from medium and highly trafficked routes as the basis for the development of such a process. This in turn allows comparison not only to the WHO studies, but also to ISO 1996-2:2017 and to the exposure-response studies that have underpinned the setting of noise objectives in NSW since 1999. In this respect, the conversion protocol has also provided for older studies to be reconstructed and compared to more contemporary studies.

Peng, J, Parnell, J & Kessissoglou, N 1970, 'Comparison of equivalent continuous noise levels and day-evening-night composite noise indicators for assessment of road traffic noise', Acoustics 2019, Sound Decisions: Moving Forward with Acoustics - Proceedings of the Annual Conference of the Australian Acoustical Society.
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Environmental road traffic noise exposure indicators adopted by Australasian road authorities, corresponding to equivalent continuous sound levels specified over different assessment time periods within a 24-hour period, are compared with 24-hour composite indicators comprising day-evening-night and day-night assessment periods that place higher importance on night-time noise impact. The aforementioned equivalent continuous sound levels specified over different assessment time periods and composite noise indicators are calculated using measured hourly road traffic noise levels at representative locations in urban and rural areas in New South Wales. Further, the corresponding road traffic data (full classification vehicle counts and vehicle speeds) are used as inputs to the well-established CNOSSOS-EU, CoRTN and FHWA-TNM road traffic noise prediction models, from which the equivalent continuous sound levels and composite noise indicators are then predicted. Using the noise indicators, measured noise levels and predicted noise levels from the three road traffic models at roadside locations along an urban arterial road and an interstate freight route are compared.

Prabowo, YA, Ranasinghe, R, Dissanayake, G, Riyanto, B & Yuliarto, B 1970, 'A Bayesian approach for gas source localization in large indoor environments', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE.
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Rahman, MM, Zhao, M, Islam, MS, Dong, K & Saha, SC 1970, 'Airflow dynamic and particle deposition in age-specific human lungs', Australasian Fluid Mechanics Conference (AFMC), 22nd Australasian Fluid Mechanics Conference AFMC2020, The University of Queensland.
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Roser, C, Langer, B & Deuse, J 1970, 'The Power of Six: Relation Between Time and Money in Manufacturing for Segments of the Value Stream', Lecture Notes in Networks and Systems, Springer International Publishing, pp. 21-28.
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© 2020, Springer Nature Switzerland AG. A major influence on the cost of a product is the time it takes to make this product. Traditional cost accounting can grasp part of this relation, but misses many critical aspects of having a faster time to the customer. Rajan Suri analyzed this relation empirically. Based on a data set with industrial data he determined an empirical mathematical relation between the turnaround time to the customer (or replenishment time) and the product cost for the entire value stream. This paper modifies the approach by Suri to be applied also to segments of the value stream, creating a relation between the cost within of a segment of a value stream and the time it takes for a part to pass through this segment of a value stream. This allows the estimation of the improvement in cost and the reduction in turnaround time also for sub-segments of the value stream, helping decision makers to better understand the impact of their decisions.

Saroya, M, Best, G & Hollinger, GA 1970, 'Online Exploration of Tunnel Networks Leveraging Topological CNN-based World Predictions', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE.
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Scheide, E, Best, G & Hollinger, GA 1970, 'Learning Behavior Trees for Robotic Task Planning by Monte Carlo Search over a Formal Grammar', RSS Workshop on Learning (in) Task and Motion Planning.

Singh, AK, Aldini, S, Leong, D, Wang, Y-K, Carmichael, MG, Liu, D & Lin, C-T 1970, 'Prediction Error Negativity in Physical Human-Robot Collaboration', 2020 8TH INTERNATIONAL WINTER CONFERENCE ON BRAIN-COMPUTER INTERFACE (BCI), 8th International Winter Conference on Brain-Computer Interface (BCI), IEEE, SOUTH KOREA, Tech Univ Berlin, Korea Univ Machine Learning Grp, BK21 Plus Global Leader, Gangwon, pp. 58-63.
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Singh, AK, Aldini, S, Leong, D, Wang, Y-K, Carmichael, MG, Liu, D & Lin, C-T 1970, 'Prediction Error Negativity in Physical Human-Robot Collaboration', 2020 8th International Winter Conference on Brain-Computer Interface (BCI), 2020 8th International Winter Conference on Brain-Computer Interface (BCI), IEEE, Gangwon, Korea (South), pp. 1-6.
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Cognitive conflict is a fundamental phenomenon of human cognition, particularly during interaction with the real world. Understanding and detecting cognitive conflict can help to improve interactions in a variety of applications, such as in human-robot collaboration (HRC), which involves continuously guiding the semi-autonomous robot to perform a task in given settings. There have been several works to detect cognitive conflict in HRC but without physical control settings. In this work, we have conducted the first study to explore cognitive conflict using prediction error negativity (PEN) in physical human-robot collaboration (pHRC). Our results show that there was a statistically significant (p =. 047) higher PEN for conflict condition compared to normal conditions, as well as a statistically significant difference between different levels of PEN (p =. 020). These results indicate that cognitive conflict can be detected in pHRC settings and, consequently, provide a window of opportunities to improve the interaction in pHRC.

Song, J, Bai, F, Zhao, L, Huang, S & Xiong, R 1970, 'Efficient two step optimization for large embedded deformation graph based SLAM', 2020 IEEE International Conference on Robotics and Automation (ICRA), 2020 IEEE International Conference on Robotics and Automation (ICRA), IEEE, pp. 9419-9425.
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© 2020 IEEE. Embedded deformation graph is a widely used technique in deformable geometry and graphical problems. Although the technique has been transmitted to stereo (or RGB-D) camera based SLAM applications, it remains challenging to compromise the computational cost as the model grows. In practice, the processing time grows rapidly in accordance with the expansion of maps. In this paper, we propose an approach to decouple the nodes of deformation graph in large scale dense deformable SLAM and keep the estimation time to be constant. We observe that only partial deformable nodes in the graph are connected to visible points. Based on this fact, the sparsity of the original Hessian matrix is utilized to split the parameter estimation into two independent steps. With this new technique, we achieve faster parameter estimation with amortized computation complexity reduced from O(n2) to almost O(1). As a result, the computational cost barely increases as the map keeps growing. Based on our strategy, the computational bottleneck in large scale embedded deformation graph based applications will be greatly mitigated. The effectiveness is validated by experiments, featuring large scale deformation scenarios.

Sutjipto, S, Lai, Y, Carmichael, MG & Paul, G 1970, 'Fitts’ law in the presence of interface inertia', 2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2020 42nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) in conjunction with the 43rd Annual Conference of the Canadian Medical and Biological Engineering Society, IEEE, Montreal, QC, Canada, Canada, pp. 4749-4752.
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Collaborative robots are advancing the healthcare frontier, in applications such as rehabilitation and physical therapy. Effective physical collaboration in human-robot systems require an understanding of partner intent and capability. Various modalities exist to convey such information between human agents, however, natural interactions between humans and robots are difficult to characterise and achieve. To enhance inter-agent communication, predictive models for human movement have been devised. One such model is Fitts' law. Many works using Fitts' law rely on massless interfaces. However, this coupling between human and robot, and the inertial effects experienced, may affect the predictive ability of Fitts' law. Experiments were conducted on human-robot dyads during a target-directed force exertion task. From the interactions, the results indicate that there is no observable effect regarding Fitts' law's predictive ability.

Thiyagarajan, K, Acharya, P, Piyathilaka, L & Kodagoda, S 1970, 'Numerical Modeling of the Effects of Electrode Spacing and Multilayered Concrete Resistivity on the Apparent Resistivity Measured Using Wenner Method', 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Kristiansand, Norway, pp. 200-206.
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Thiyagarajan, K, Kodagoda, S & Ulapane, N 1970, 'Short-term Time Series Forecasting of Concrete Sewer Pipe Surface Temperature', 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), IEEE, Shenzhen, China, pp. 1194-1199.
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Thiyagarajan, K, Kodagoda, S, Ulapane, N & Prasad, M 1970, 'A Temporal Forecasting Driven Approach Using Facebook’s Prophet Method for Anomaly Detection in Sewer Air Temperature Sensor System', 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Kristiansand, Norway, pp. 25-30.
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To, D & Huynh, BP 1970, 'Desalination Using Simple Materials', Australasian Fluid Mechanics Conference (AFMC), 22nd Australasian Fluid Mechanics Conference AFMC2020, The University of Queensland.
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To, KYC, Lee, JJH, Yoo, C, Anstee, S & Fitch, R 1970, 'Streamline-Based Control of Underwater Gliders in 3D Environments', 2019 IEEE 58th Conference on Decision and Control (CDC), 2019 IEEE 58th Conference on Decision and Control (CDC), IEEE, Nice, France, pp. 8303-8310.
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Autonomous underwater gliders use buoyancy control to achieve forwardpropulsion via a sawtooth-like, rise-and-fall trajectory. Because gliders areslow-moving relative to ocean currents, glider control must consider the effectof oceanic flows. In previous work, we proposed a method to control underwatervehicles in the (horizontal) plane by describing such oceanic flows in terms ofstreamlines, which are the level sets of stream functions. However, the generalanalytical form of streamlines in 3D is unknown. In this paper, we show howstreamline control can be used in 3D environments by assuming a 2.5D model ofocean currents. We provide an efficient algorithm that acts as a steeringfunction for a single rise or dive component of the glider's sawtoothtrajectory, integrate this algorithm within a sampling-based motion planningframework to support long-distance path planning, and provide several examplesin simulation in comparison with a baseline method. The key to our method'scomputational efficiency is an elegant dimensionality reduction to a 1D controlregion. Streamline-based control can be integrated within varioussampling-based frameworks and allows for online planning for gliders incomplicated oceanic flows.

Ulapane, N, Thiyagarajan, K & Kodagoda, S 1970, 'Binary Spectrum Feature for Improved Classifier Performance', 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), 2020 16th International Conference on Control, Automation, Robotics and Vision (ICARCV), IEEE, Shenzhen, China, pp. 1117-1122.
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Ulapane, N, Thiyagarajan, K & Kodagoda, S 1970, 'Hyper-Parameter Initialization for Squared Exponential Kernel-based Gaussian Process Regression', 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Kristiansand, Norway, pp. 1154-1159.
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Ulapane, N, Thiyagarajan, K & Kodagoda, S 1970, 'System Identification of Static Nonlinear Elements: A Unified Approach of Active Learning, Over-fit Avoidance, and Model Structure Determination', 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Kristiansand, Norway, pp. 1001-1006.
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Usayiwevu, M, Le Gentil, C, Mehami, J, Yoo, C, Fitch, R & Vidal-Calleja, T 1970, 'Information Driven Self-Calibration for Lidar-Inertial Systems', 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Las Vegas, NV, USA, pp. 9961-9967.
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Multi-modal estimation systems have the advantage of increased accuracy and robustness. To achieve accurate sensor fusion with these types of systems, a reliable extrinsic calibration between each sensor pair is critical. This paper presents a novel self-calibration framework for lidar-inertial systems. The key idea of this work is to use an informative path planner to find the admissible path that produces the most accurate calibration of such systems in an unknown environment within a given time budget. This is embedded into a simultaneous localization, mapping and calibration lidar-inertial system, which involves challenges in dealing with agile motions for excitation and large amount of data. Our approach has two stages: firstly, the environment is explored and mapped following a pre-defined path; secondly, the map is exploited to find a continuous and differentiable path that maximises the information gain within a sampling-based planner. We evaluate the proposed self-calibration method in a simulated environment and benchmark it with standard predefined paths to show its performance.

Wang, T, Lu, W, Yan, Z & Liu, D 1970, 'DOB-Net: Actively Rejecting Unknown Excessive Time-Varying Disturbances', 2020 IEEE International Conference on Robotics and Automation (ICRA), 2020 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Paris, France, pp. 1881-1887.
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This paper presents an observer-integrated Reinforcement Learning (RL) approach, called Disturbance OB-server Network (DOB-Net), for robots operating in environments where disturbances are unknown and time-varying, and may frequently exceed robot control capabilities. The DOB-Net integrates a disturbance dynamics observer network and a controller network. Originated from conventional DOB mechanisms, the observer is built and enhanced via Recurrent Neural Networks (RNNs), encoding estimation of past values and prediction of future values of unknown disturbances in RNN hidden state. Such encoding allows the controller generate optimal control signals to actively reject disturbances, under the constraints of robot control capabilities. The observer and the controller are jointly learned within policy optimization by advantage actor critic. Numerical simulations on position regulation tasks have demonstrated that the proposed DOB-Net significantly outperforms conventional feedback controllers and classical RL policy.

Wocker, M, Betz, NK, Feuersänger, C, Lindworsky, A & Deuse, J 1970, 'Unsupervised Learning for Opportunistic Maintenance Optimization in Flexible Manufacturing Systems', Procedia CIRP, Elsevier BV, pp. 1025-1030.
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© 2020 The Authors. Large scale manufacturing systems with a high degree in automation and the ability to produce several product variants in parallel meet current requirements of a highly flexible and at the same time productive manufacturing process. In practice, however, the non-transparency as well as the complexity of these systems overwhelm the maintenance department in the effective planning and implementation of maintenance tasks. As a result, major maintenance tasks are postponed to non-production times which causes increased maintenance cost as well as a decrease in system availability. This research explores a method that uses unsupervised learning algorithms to analyze type mixes and related process performances inside the system. The information is used to determine the optimal master production schedule prior to maintenance activities which leads to more frequent and extended time windows for maintenance activities during production time and thus to an increase in system availability.

Wostmann, R, Schlunder, P, Temme, F, Klinkenberg, R, Kimberger, J, Spichtinger, A, Goldhacker, M & Deuse, J 1970, 'Conception of a Reference Architecture for Machine Learning in the Process Industry', 2020 IEEE International Conference on Big Data (Big Data), 2020 IEEE International Conference on Big Data (Big Data), IEEE.
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Yoo, C, Lensgraf, S, Fitch, R, Clemon, LM & Mettu, R 1970, 'Toward Optimal FDM Toolpath Planning with Monte Carlo Tree Search', Proceedings - IEEE International Conference on Robotics and Automation, pp. 4037-4043.
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The most widely used methods for toolpath planning in fused deposition 3Dprinting slice the input model into successive 2D layers in order to constructthe toolpath. Unfortunately slicing-based methods can incur a substantialamount of wasted motion (i.e., the extruder is moving while not printing),particularly when features of the model are spatially separated. In recentyears we have introduced a new paradigm that characterizes the space offeasible toolpaths using a dependency graph on the input model, along withseveral algorithms to search this space for toolpaths that optimize objectivefunctions such as wasted motion or print time. A natural question that arisesis, under what circumstances can we efficiently compute an optimal toolpath? Inthis paper, we give an algorithm for computing fused deposition modeling (FDM)toolpaths that utilizes Monte Carlo Tree Search (MCTS), a powerfulgeneral-purpose method for navigating large search spaces that is guaranteed toconverge to the optimal solution. Under reasonable assumptions on printergeometry that allow us to compress the dependency graph, our MCTS-basedalgorithm converges to find the optimal toolpath. We validate our algorithm ona dataset of 75 models and show it performs on par with our previous best localsearch-based algorithm in terms of toolpath quality. In prior work wespeculated that the performance of local search was near optimal, and weexamine in detail the properties of the models and MCTS executions that lead tobetter or worse results than local search.

Zhang, Y, Falque, R, Zhao, L, Huang, S & Hu, B 1970, 'Deep Learning Assisted Automatic Intra-operative 3D Aortic Deformation Reconstruction', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Springer International Publishing, pp. 660-669.
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Endovascular interventions rely on 2D X-ray fluoroscopy for 3D catheter manipulation. The dynamic nature of aorta prevents the pre-operative CT/MRI data to be used directly as the live 3D guidance since the vessel deforms during the surgery. This paper provides a framework that reconstructs the live 3D aortic shape by fusing a 3D static pre-operative model and the 2D intra-operative fluoroscopic images. The proposed framework recovers aortic 3D shape automatically and computationally efficient. A deep learning approach is adopted as the front-end for extracting features from fluoroscopic images. A signed distance field based correspondence method is employed for avoiding the repeated feature-vertex matching while maintaining the correspondence accuracy. The warp field of 3D deformation is estimated by solving a non-linear least squares problem based on the embedded deformation graph. Detailed phantom experiments are conducted, and the results demonstrate the accuracy of the proposed framework as well as the potential clinical value of the technique.

Zhang, Y, Zhao, L & Huang, S 1970, 'Aortic 3D Deformation Reconstruction using 2D X-ray Fluoroscopy and 3D Pre-operative Data for Endovascular Interventions', 2020 IEEE International Conference on Robotics and Automation (ICRA), 2020 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Paris, France (Virtual), pp. 2393-2399.
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Current clinical endovascular interventions rely on 2D guidance for catheter manipulation. Although an aortic 3D surface is available from the pre-operative CT/MRI imaging, it cannot be used directly as a 3D intra-operative guidance since the vessel will deform during the procedure. This paper aims to reconstruct the live 3D aortic deformation by fusing the static 3D model from the pre-operative data and the 2D live imaging from fluoroscopy. In contrast to some existing deformation reconstruction frameworks which require 3D observations such as RGB-D or stereo images, fluoroscopy only presents 2D information. In the proposed framework, a 2D-3D registration is performed and the reconstruction process is formulated as a non-linear optimization problem based on the deformation graph approach. Detailed simulations and phantom experiments are conducted and the result demonstrates the reconstruction accuracy and robustness, as well as the potential clinical value of this framework.

Zhong, J, Xiao, T, Halkon, B, Kirby, R & Qiu, X 1970, 'An experimental study on the active noise control using a parametric array loudspeaker', Proceedings of 2020 International Congress on Noise Control Engineering, INTER-NOISE 2020, Seoul, Korea.
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An active noise control (ANC) system using a parametric array loudspeaker (PAL) was designed to cancel broadband noise at a person's ear, where a custom-made low-mass membrane pick-up from a retroreflective film and a laser Doppler vibrometer was used to form a remote sensing apparatus to determine the acoustic information with minimum obstructions to the person. The experiment results show that such an ANC system can achieve similar overall noise reductions from 1 kHz to 6 kHz at the ear as a similar one albeit using a traditional omnidirectional loudspeaker. The noise reductions at nine points around the person were used to evaluate the effects of the ANC system in the other areas, and the results show the side effect of the ANC system with the PAL is much smaller than that with the traditional loudspeaker due to the sharp radiation directivity of the PAL. It is also shown that when the PAL was placed away from the person, the ANC performance and the side effect to the other areas remained similar due to its low geometrical spreading attenuation, but the side effect caused by a traditional loudspeaker to the other areas increased with its distance to the person.

Zwinkau, R, Frentrup, S, Möhle, R & Deuse, J 1970, 'Automatic Particle Classification Through Deep Learning Approaches for Increasing Productivity in the Technical Cleanliness Laboratory', Advances in Intelligent Systems and Computing, Springer International Publishing, pp. 34-44.
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© Springer Nature Switzerland AG 2020. Understanding the properties of particles plays a vital role in assessing the component cleanliness and its origin in the manufacturing process. We propose a classification method using deep convolutional neural networks. Using a dataset of 70,000 annotated images, we achieve a accuracy of 97.7% for a binary classification in metal and non-metal particles comparable to state-of-the-art polarized light microscopy according to VDA 19-1 and ISO 16232. Manual follow-up checks in a cleanliness laboratory are not required due to the robustness of the classification system.

Hossain, MI 2020, 'Modelling and Simulation of Multiple Galloping Quadrupedal Dynamics'.
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The work presented in this dissertation is comprised of three distinct parts. Namely data modelling and analysis for galloping quadruped dynamics, numerically mod elling race track path design, and numerically simulating multiple galloping quadrupeds race dynamics. Fundamentally, all the parts are interlinked to one another at the level of searching for dynamics stability of galloping quadrupeds. A holistic approach was taken for information synthesising, ranging from data acquisition to modelling and simulation. The dissertation presents an overview of the current progress in the field, approaches the problem by linking information from modelling, then derives numerical solutions to come to conclusions.Data modelling demonstrated greyhound galloping gait performance and existing race track design conditions. The techniques utilised for data gathering and analysis allowed effective retrieval of diverse information. Racing greyhound galloping gait performance was verified including speed, acceleration, yaw rate, stride frequency, stride length and paw dynamics. Also, reviewing of existing tracks revealed track designs limitations.Data modelling showed that trajectory dynamics could significantly influence race dynamics stability. Thus, methods were derived for modelling and designing gal loping greyhound ideal path trajectory between a straight and curve track path segments. To do this, clothoid and algebraic curved segments were numerically gen erated using a sequential vector transformation method that allows the inclusion of greyhound kinematic parameters. And an equation was derived to model suitable clothoid segments which represents greyhound kinematic parameters and boundary conditions of a track. Finally, results from race data modelling and past injury data are also provided to support transition curve segments improving the dynamics and safety of racing greyhounds while reducing injuries.A race simulation platform was created which emulat...

Liu, L, Fryc, S, Wu, L, Vu, T, Paul, G & Vidal-Calleja, T 2020, 'Active and Interactive Mapping with Dynamic Gaussian Process Implicit Surfaces for Mobile Manipulators', arXiv.

Oberst, S, Halkon, B, Ji, J & Brown, T 2020, 'Vibration Engineering for a Sustainable Future Numerical and Analytical Methods to Study Dynamical Systems, Vol. 3', Springer.
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This volume presents the proceedings of the Asia-Pacific Vibration Conference (APVC) 2019, "Vibration Engineering for a Sustainable Future," emphasizing work devoted to experimental methods and verification.

Pearce, C, Guertler, M & Harvard, H 2020, 'The next wave (3D printing at UTS)', Manufacturers' Monthly.
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Media article about additive manufacturing/3D printing at UTS and possibilities of engaging with FEIT, Rapido and ProtoSpace.

Stender, M, Tiedemann, M, Spieler, D, Schoepflin, D, Hofffmann, N & Oberst, S 2020, 'Deep learning for brake squeal: vibration detection, characterization and prediction'.
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Despite significant advances in modeling of friction-induced vibrations andbrake squeal, the majority of industrial research and design is still conductedexperimentally, since many aspects of squeal and its mechanisms involved remainunknown. We report here for the first time on novel strategies for handlingdata-intensive vibration testings to gain better insights into friction brakesystem vibrations and noise generation mechanisms. Machine learning-basedmethods to detect and characterize vibrations, to understand sensitivities andto predict brake squeal are applied with the aim to illustrate howinterdisciplinary approaches can leverage the potential of data sciencetechniques for classical mechanical engineering challenges. In the first part,a deep learning brake squeal detector is developed to identify several classesof typical friction noise recordings. The detection method is rooted in recentcomputer vision techniques for object detection based on convolutional neuralnetworks. It allows to overcome limitations of classical approaches that solelyrely on instantaneous spectral properties of the recorded noise. Resultsindicate superior detection and characterization quality when compared to astate-of-the-art brake squeal detector. In the second part, a recurrent neuralnetwork is employed to learn the parametric patterns that determine the dynamicstability of an operating brake system. Given a set of multivariate loadingconditions, the RNN learns to predict the noise generation of the structure.The validated RNN represents a virtual twin model for the squeal behavior of aspecific brake system. It is found that this model can predict the occurrenceand the onset of brake squeal with high accuracy and that it can identify thecomplicated patterns and temporal dependencies in the loading conditions thatdrive the dynamical structure into regimes of instability.

Thiyagarajan, K, Acharya, P, Piyathilaka, L & kodagoda, S 2020, 'Numerical Modeling of the Effects of Electrode Spacing and Multilayered Concrete Resistivity on the Apparent Resistivity Measured Using Wenner Method', Institute of Electrical and Electronics Engineers (IEEE).
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Thiyagarajan, K, kodagoda, S & Ulapane, N 2020, 'Short-term Time Series Forecasting of Concrete Sewer Pipe Surface Temperature', Institute of Electrical and Electronics Engineers (IEEE).
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Thiyagarajan, K, kodagoda, S & Ulapane, N 2020, 'Short-term Time Series Forecasting of Concrete Sewer Pipe Surface Temperature', Institute of Electrical and Electronics Engineers (IEEE).
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Thiyagarajan, K, kodagoda, S, Ulapane, N & prasad, M 2020, 'A Temporal Forecasting Driven Approach Using Facebook’s Prophet Method for Anomaly Detection in Sewer Air Temperature Sensor System', Institute of Electrical and Electronics Engineers (IEEE).
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Thiyagarajan, K, kodagoda, S, Ulapane, N & prasad, M 2020, 'A Temporal Forecasting Driven Approach Using Facebook’s Prophet Method for Anomaly Detection in Sewer Air Temperature Sensor System', Institute of Electrical and Electronics Engineers (IEEE).
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To, KYC, Lee, JJH, Yoo, C, Anstee, S & Fitch, R 2020, 'Streamline-Based Control of Underwater Gliders in 3D Environments', arXiv.

Ulapane, N, Thiyagarajan, K & kodagoda, S 2020, 'Binary Spectrum Feature for Improved Classifier Performance', Institute of Electrical and Electronics Engineers (IEEE).
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Ulapane, N, Thiyagarajan, K & kodagoda, S 2020, 'Binary Spectrum Feature for Improved Classifier Performance', Institute of Electrical and Electronics Engineers (IEEE).
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Ulapane, N, Thiyagarajan, K & kodagoda, S 2020, 'Hyper-Parameter Initialization for Squared Exponential Kernel-based Gaussian Process Regression', Institute of Electrical and Electronics Engineers (IEEE).
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Ulapane, N, Thiyagarajan, K & kodagoda, S 2020, 'Hyper-Parameter Initialization for Squared Exponential Kernel-based Gaussian Process Regression', Institute of Electrical and Electronics Engineers (IEEE).
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Ulapane, N, Thiyagarajan, K & kodagoda, S 2020, 'System Identification of Static Nonlinear Elements: A Unified Approach of Active Learning, Over-fit Avoidance, and Model Structure Determination', Institute of Electrical and Electronics Engineers (IEEE).
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Ulapane, N, Thiyagarajan, K & kodagoda, S 2020, 'System Identification of Static Nonlinear Elements: A Unified Approach of Active Learning, Over-fit Avoidance, and Model Structure Determination', Institute of Electrical and Electronics Engineers (IEEE).
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Yoo, C, Lensgraf, S, Fitch, R, Clemon, LM & Mettu, R 2020, 'Toward Optimal FDM Toolpath Planning with Monte Carlo Tree Search', arXiv.