Publications

Farhad Ismail, M & Saha, SC 2018, 'Enhancement of Confined Air Jet Impingement Heat Transfer Using Perforated Pin-Fin Heat Sinks' in Application of Thermo-fluid Processes in Energy Systems, Springer Singapore, pp. 231-243.
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© Springer Nature Singapore Pte Ltd. 2018. The development of semiconductor fabrication process and electronic packaging technology causes the size and weight of electronic components to decrease consistently. Along with the increasing operating power, the heat generation rate of the electronic products apparently gets higher. For the sustainable future, we must limit using natural resources and also reduce the greenhouse gas emission. Efficient removal of heat from the electronic products in a limited space becomes a major task in electronics cooling. Air impingement cooling with a heat sink is an attractive option for electronic cooling, because it is inexpensive, robust, and localized. Rapid heat transfer from heated surfaces and reducing material weight is also becoming a major task for the design of heat exchanger equipment for electronic cooling. Rectangular plate fins as extended surfaces are good heat transfer equipment which are widely used for various industrial applications. Heat transfer rate can be improved by introducing perforations, porosity, or slots. Moreover, due to restrictions in setup space and economic reasons, heat transfer equipment has been required to be much more compact in size and lighter in weight. Studies on three-dimensional plate and pin-fin heat sinks are extensive. But no focus has been yet given on air jet impingement heat transfer with perforated pin-fin heat sink. Thermal-fluid characteristics of solid and perforated pin-fin heat sinks cooled by confined air jet impingement are investigated numerically in this study. The SST k-ω turbulence model is used to predict the turbulence flow parameters. The numerical model is verified with previously published experimental data. Flow and heat transfer characteristics are presented for the impinging Reynolds number, Re = 5000−25000 having constant impingement distance (Y/D = 8), fin width (W/L = 0.1), and height (H/L = 0.5). The main objective of this study is to examine the effects ...

Islam, M, Saha, SC, Karim, MA & Yarlagadda, PKDV 2018, 'A Method of Three-Dimensional Thermo-Fluid Simulation of the Receiver of a Standard Parabolic Trough Collector' in Application of Thermo-fluid Processes in Energy Systems, Springer Singapore, Germany, pp. 203-230.
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© Springer Nature Singapore Pte Ltd. 2018. A parabolic trough collector (PTC) is the most proven concentrating collector system for indirect steam generation in solar thermal power plants. The receiver of the collector is fabricated enveloping a metal absorber tube using an evacuated glass tube. Depending on the level of evacuation, the glass envelope reduces the convection heat loss from the tube almost to zero. However, sometimes the envelopes are broken, damaged or removed that causes potential convection loss from an open-to-air receiver tube. On the other hand, the solar irradiance profile around the receiver tube is likely to be highly nonuniform. In order to study the heat transfer mechanism of an exposed receiver tube of a standard PTC under the actual optical and environmental conditions, a 3-dimensional Computational Conjugate Heat Transfer (CCHT) model of the receiver tube was developed. The CCHT model was developed applying finite volume technique of computational fluid dynamics integrating with a verified Monte Carlo ray tracing optical model. The CCHT model was verified extensively, and different heat loss models were developed to investigate the heat loss characteristics. The convection heat loss from the outer surface of the receiver tube was observed very high as it was exposed to a high-temperature gradient with its surroundings. Therefore, it is obvious that the receiver tube should be enveloped and evacuated properly. A well-managed and efficiently operated PTC solar energy field could be the best candidate for sustainable energy management for a sustainable future.

Saha, SC, Gu, YT & Khan, MMK 2018, 'Heat Transfer Enhancement in a Baffled Attic-Shaped Space' in Application of Thermo-fluid Processes in Energy Systems, Springer Singapore, Singapore, pp. 157-172.
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© Springer Nature Singapore Pte Ltd. 2018. To reduce the natural convection heat loss from attic-shaped spaces, many researchers used convection suppression devices in the past. In this chapter, a single baffle is used under the top tip to investigate numerically the natural convection heat loss in an attic-shaped enclosure, which is a cost-effective approach. The case considered in this chapter is one inclined wall of the enclosure which is uniformly heated while the other inclined wall uniformly cooled with adiabatic bottom wall. The finite volume method has been used to discretize the governing equations, with the QUICK scheme approximating the advection term. The diffusion terms are discretized using central differencing with second-order accuracy. A wide range of governing parameters is studied (Rayleigh number, aspect ratio, baffle length, etc.). It is observed that the heat transfer due to natural convection in the enclosure reduces when the baffle length is increased. Effects of other parameters on heat transfer and flow field are described in this study.

Tong, L & Luo, Q 2018, 'Analytical Approach' in Handbook of Adhesion Technology, Springer International Publishing, Switzerland, pp. 665-700.
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© Springer International Publishing AG, part of Springer Nature 2018. All rights are reserved. This chapter presents analytical approach for determining stress and strength of adhesively bonded joints. Selected applications of adhesively bonded joints are discussed first, and then mathematical models for stress analysis of these joints are outlined. Various closed-form solutions for adhesive stresses and edge bending moment for balanced single-lap joints are presented and compared. The method for finding analytical solutions for asymmetric and unbalanced adhesive joints is also discussed. Explicit expressions for mode I and mode II energy release rates for cohesive failure and interfacial debonding are presented for asymmetric joints with a semi-infinitive length subjected to general load combinations.

Zheng, J & Luo, Z 2018, 'Reliability-Based Topology Optimization for Continuum Structures with Non-probabilistic Uncertainty' in Advances in Structural and Multidisciplinary Optimization, Springer International Publishing, Switzerland, pp. 390-395.
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A non-probabilistic reliability-based topology optimization (NRBTO) method for continuum structures is proposed for structures with correlated interval parameters based on the multidimensional parallelepiped (MP) model. A topology optimization model is formulated to minimize volume of structure under displacement constraints. An equivalent optimization model is given and solved based on the efficient performance measurement approach (PMA). A numerical example is used to demonstrate the effectiveness of the proposed method.

Acosta, E, Wight, NM, Smirnov, V, Buckman, J & Bennett, NS 2018, 'Hydrogenated Nano-/Micro-Crystalline Silicon Thin-Films for Thermoelectrics', Journal of Electronic Materials, vol. 47, no. 6, pp. 3077-3084.
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© 2017, The Minerals, Metals & Materials Society. Thermoelectric technology has not yet been able to reach full-scale market penetration partly because most commercial materials employed are scarce/costly, environmentally unfriendly and in addition provide low conversion efficiency. The necessity to tackle some of these hurdles leads us to investigate the suitability of n-type hydrogenated microcrystalline silicon (μc-Si: H) in the fabrication of thermoelectric devices, produced by plasma enhanced chemical vapour deposition (PECVD), which is a mature process of proven scalability. This study reports an approach to optimise the thermoelectric power factor (PF) by varying the dopant concentration by means of post-annealing without impacting film morphology, at least for temperatures below 550°C. Results show an improvement in PF of more than 80%, which is driven by a noticeable increase of carrier mobility and Seebeck coefficient in spite of a reduction in carrier concentration. A PF of 2.08 × 10−4 W/mK2 at room temperature is reported for n-type films of 1 μm thickness, which is in line with the best values reported in recent literature for similar structures.

Al-Zubaydi, AYT & Hong, G 2018, 'Experimental investigation of counter flow heat exchangers for energy recovery ventilation in cooling mode', International Journal of Refrigeration, vol. 93, pp. 132-143.
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© 2018 Elsevier Ltd and IIR Ventilation heat recovery is a system that requires low power to operate and has a high capacity to reduce the energy consumption and increase the overall efficiency for air conditioning. This paper reports the experimental investigation of air-to-air heat exchangers employed for heat recovery ventilation in cooling mode. The two main objective of this research are to design, fabricate and testing two polymers heat exchangers of different plate geometries and to evaluate and compare the thermal performance two quasi-counter flow plate heat exchangers. The key aims were to evaluate the effect of the surface geometry of the plates heat exchanger on the performance parameters specified in ANSI/ASHRAE Standard 84 and ANSI/AHRI Standard 1060 and narrow the gap of the limited experimental comparison of polymers sensible heat exchanger in cooling mode. The experiments were conducted on two polymer heat exchangers, one with a flat plate and the other with a dimpled surface plate. The experimental results showed that the cooling capacity of the dimpled surface heat exchanger as ventilation heat recovery system in cooling mode was 50–60% better than that of the flat surface plate heat exchanger. In addition, the sensible efficiency of the dimpled surface heat exchanger was higher than that of the flat surface plates heat exchanger at lower air velocities and higher air initial temperatures. The highest COP was 6.6 achieved with dimpled surface heat exchanger under primary air operating temperature of 32.6 °C.

Barker, RA, Eager, D & Sharwood, LN 2018, 'Ensuring safety in public playgrounds is everybody's business.', Med J Aust, vol. 210, no. 1, pp. 9-11.
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When an injury occurs in a children’s playground, who is responsible? Media headlines1,2 have highlighted risks associated with a recently opened playground in north-western Sydney. The playground’s giant tube slide was closed following a spate of injuries to both adult and child patrons. With injuries described as “horrific”, the media questioned “how the 30 m long, 14 m tall slide passed safety rules”.1 While playground injuries are fairly common,3 there are specific multilevel responsibilities required to balance the importance of play and physical activity with mitigation of injury risk. In this article, we review the role of standards in industry governance and injury prevention.

Best, G, Faigl, J & Fitch, R 2018, 'Online planning for multi-robot active perception with self-organising maps', Autonomous Robots, vol. 42, no. 4, pp. 715-738.
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© 2017, Springer Science+Business Media, LLC, part of Springer Nature. We propose a self-organising map (SOM) algorithm as a solution to a new multi-goal path planning problem for active perception and data collection tasks. We optimise paths for a multi-robot team that aims to maximally observe a set of nodes in the environment. The selected nodes are observed by visiting associated viewpoint regions defined by a sensor model. The key problem characteristics are that the viewpoint regions are overlapping polygonal continuous regions, each node has an observation reward, and the robots are constrained by travel budgets. The SOM algorithm jointly selects and allocates nodes to the robots and finds favourable sequences of sensing locations. The algorithm has a runtime complexity that is polynomial in the number of nodes to be observed and the magnitude of the relative weighting of rewards. We show empirically the runtime is sublinear in the number of robots. We demonstrate feasibility for the active perception task of observing a set of 3D objects. The viewpoint regions consider sensing ranges and self-occlusions, and the rewards are measured as discriminability in the ensemble of shape functions feature space. Exploration objectives for online tasks where the environment is only partially known in advance are modelled by introducing goal regions in unexplored space. Online replanning is performed efficiently by adapting previous solutions as new information becomes available. Simulations were performed using a 3D point-cloud dataset from a real robot in a large outdoor environment. Our results show the proposed methods enable multi-robot planning for online active perception tasks with continuous sets of candidate viewpoints and long planning horizons.

Bhowmick, S, Xu, F, Zhang, X & Saha, SC 2018, 'Natural convection and heat transfer in a valley shaped cavity filled with initially stratified water', International Journal of Thermal Sciences, vol. 128, pp. 59-69.
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© 2018 Elsevier Masson SAS Fog is omnipresent in the natural environment, namely valleys and mountains. A strong comprehension of the fluid flow dynamics pertaining to fog formation is of crucial importance. In the present study, the two-dimensional numerical method is used to investigate the transient natural convection in a valley-shaped triangular cavity initially filled with stratified water. A wide range of Rayleigh numbers (2.26 × 105–2.26 × 109) and aspect ratios (0.1–1.0) are considered. The numerical results are verified against experimental results. The development of natural convection flows in the cavity from the start up to the steady state is classified into two stages: an early stage and a transitional stage. Transient natural convection flows in the cavity are described. Spectral analysis is performed for different governing parameters. A simple scaling analysis is performed for the thermal boundary layer and the time scale of the stratification breakup describing the disappearance of fog in the valley is obtained and validated by numerical results. Additionally, mass and heat transfer in the cavity is measured and the scaling relation between the Nusselt number and the Rayleigh number for different aspect ratios are presented.

Boostani, AF, Yazdani, S, Khosroshahi, RA, Jiang, ZY & Wei, D 2018, 'A novel graphene-stimulated semi-solid processing to fabricate advanced aluminium matrix nanocomposites', Materials Science and Engineering: A, vol. 736, pp. 316-322.
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© 2018 Elsevier B.V. This study reveals an unprecedented capacity of flake graphene sheets in manipulating semi-solid deformation of aluminium matrix nanocomposites by restricting the grain growth of the nanograins during the reheating process to significantly enhance (173%) the yield strength of the fabricated composites. The graphene sheets with onion shape have also shown the unique capability in alleviating the agglomeration of SiC nanoparticles, attributed to the manipulated Hamaker constant of these particles as a result of wrapping graphene sheets. A devised mathematical approach has authenticated, for the first time, the effect of wrapping graphene sheets on subtle adjusting the Hamaker constant of SiC nanoparticles to stimulate engulfment of these nanoparticles within solidifying matrix rather than agglomeration at grain boundaries. This, therefore, has resulted in diminishing the porosity and stimulating multi-scaled micro/nano grains, thereby significantly enhancing the tensile properties of the fabricated composites.

Brennan, MJ, Karimi, M, Muggleton, JM, Almeida, FCL, Kroll de Lima, F, Ayala, PC, Obata, D, Paschoalini, AT & Kessissoglou, N 2018, 'On the effects of soil properties on leak noise propagation in plastic water distribution pipes', Journal of Sound and Vibration, vol. 427, pp. 120-133.
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Cheng, X, Jiang, Z, Monaghan, BJ, Longbottom, RJ, Wei, D, Hee, AC & Jiang, L 2018, 'Degradation of ferritic stainless steels at 1200 °C in air', Materials and Corrosion, vol. 69, no. 1, pp. 63-75.
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Three commercial ferritic stainless steels were investigated at 1200 °C by a thermogravimetric analyser (TGA) in air. The oxidation kinetics of the ferritic stainless steels differed significantly. The adhesion of the Cr2O3 scale, the morphology of the SiO2, with or without (Cr, Mn)3O4 spinel on the top can greatly influence the oxidation and the degradation behaviour of the steels. Although the SUS430 steel had less Cr among the ferritic stainless steels (16.2 wt% Cr), it did not show more degradation behaviour than the B443NT steel (21.0 wt% Cr). The spallation of the protective oxide scale on the B443NT steel was caused by vacancy condensation at the scale/substrate interface where the SiO2 particles were and the developed compressive stresses within the oxide scale during oxidation. (Cr, Mn)3O4 spinel on the top of the Cr2O3 scale on the B445J1M steel influenced its evaporation rate. The thermodynamic aspect of the chemical composition and oxidation atmosphere of the Fe–Cr–O system was also discussed.

Clemon, LM & Zohdi, TI 2018, 'On the tolerable limits of granulated recycled material additives to maintain structural integrity', Construction and Building Materials, vol. 167, pp. 846-852.
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© 2018 Elsevier Ltd Production and maker spaces are increasingly generating mixed plastic material waste of varying quality from 3-D printers. Industrial interest is growing in embedding granulated recycled particulate material additives into a virgin binding matrix. Examples include the introduction of granulated mixed recycled materials into 3-D printer material, concrete, and pavement. The stress load-sharing between the particulate additive and the binding matrix is an important factor in design and development of these composite materials. With mixed material additives, a designer is interested in the variation of such predicted load-sharing. However, experimental development is costly and time-consuming, thus analytical and semi-analytical estimates are desired for accelerated development. In this work, we expand on previous analytically correlated phase-averaged micro- and macrostructural loading to include variational effects present in mixed recycled material. In addition, model trade-offs are provided to aid designers in quickly selecting application specific mixtures. This framework identifies the stress contributions, and their variation, to reduce product development time and costs, which could greatly accelerate material recycling and reuse for improved infrastructure materials, low-cost 3-D printer filament, and reduced waste towards a more circular economy.

DU, Y 2018, 'Topology Optimization of Multiple Materials Compliant Mechanisms Based on Sequence Interpolation Model and Multigrid Method', Journal of Mechanical Engineering, vol. 54, no. 13, pp. 47-47.
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Multi-material flexible mechanism topology optimization based on Solid isotropic material with penalization (SIMP) is to decompose the original problem into several sub-problems for layer optimization, which increases the number of design variables exponentially. The method utilizes the traditional finite element discretization. In order to obtain a clear topology, the number of meshes is inevitably huge. These two factors cause the computational efficiency of the method to be low. Therefore, based on the power function polynomial, the sequence interpolation model is proposed, and the multi-material layout iteration is used to make the different materials gather in the design domain to a plurality of predefined material points. It can be completed under a single optimization framework without decomposing into sub-problems. Topology optimization of materials without increasing the number of design variables. Aiming at the maximum geometric gain of the mechanism, a multi-material flexible mechanism topology optimization model is established. In the process of solving the governing equations by using finite element method, the multi-grid method is introduced. The meshing granularity progressively moves the displacement field of the coarse mesh horizontally as the initial field quantity on the fine mesh, avoiding directly using the fine mesh to design the domain. The high computational cost problem caused by the overall dispersion improves the calculation efficiency. The improved optimization criterion method is used to solve the model, and the multi-material flexible mechanism with optimal sequence layout is obtained. The effectiveness of the proposed method is verified by a typical example and the corresponding results of SIMP-based methods.

Ghaffari Jadidi, M, Valls Miro, J & Dissanayake, G 2018, 'Gaussian processes autonomous mapping and exploration for range-sensing mobile robots', Autonomous Robots, vol. 42, no. 2, pp. 273-290.
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© 2017, Springer Science+Business Media, LLC. Most of the existing robotic exploration schemes use occupancy grid representations and geometric targets known as frontiers. The occupancy grid representation relies on the assumption of independence between grid cells and ignores structural correlations present in the environment. We develop a Gaussian processes (GPs) occupancy mapping technique that is computationally tractable for online map building due to its incremental formulation and provides a continuous model of uncertainty over the map spatial coordinates. The standard way to represent geometric frontiers extracted from occupancy maps is to assign binary values to each grid cell. We extend this notion to novel probabilistic frontier maps computed efficiently using the gradient of the GP occupancy map. We also propose a mutual information-based greedy exploration technique built on that representation that takes into account all possible future observations. A major advantage of high-dimensional map inference is the fact that such techniques require fewer observations, leading to a faster map entropy reduction during exploration for map building scenarios. Evaluations using the publicly available datasets show the effectiveness of the proposed framework for robotic mapping and exploration tasks.

Girish, B, Gainder, S, Saha, SC & Krishnappa, D 2018, 'Rare Presentation of Catastrophic Antiphospholipid Syndrome with Myocarditis in Post-partum Period: Case Report and Review of Literature', The Journal of Obstetrics and Gynecology of India, vol. 68, no. 1, pp. 70-72.
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Hassan, M, Liu, D & Paul, G 2018, 'Collaboration of Multiple Autonomous Industrial Robots through Optimal Base Placements', Journal of Intelligent & Robotic Systems, vol. 90, no. 1-2, pp. 113-132.
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© 2017, Springer Science+Business Media B.V. Multiple autonomous industrial robots can be of great use in manufacturing applications, particularly if the environment is unstructured and custom manufacturing is required. Autonomous robots that are equipped with manipulators can collaborate to carry out manufacturing tasks such as surface preparation by means of grit-blasting, surface coating or spray painting, all of which require complete surface coverage. However, as part of the collaboration process, appropriate base placements relative to the environment and the target object need to be determined by the robots. The problem of finding appropriate base placements is further complicated when the object under consideration is large and has a complex geometric shape, and thus the robots need to operate from a number of base placements in order to obtain complete coverage of the entire object. To address this problem, an approach for Optimization of Multiple Base Placements (OMBP) for each robot is proposed in this paper. The approach aims to optimize base placements for multi-robot collaboration by taking into account task-specific objectives such as makespan, fair workload division amongst the robots, and coverage percentage; and manipulator-related objectives such as torque and manipulability measure. In addition, the constraint of robots maintaining an appropriate distance between each other and relative to the environment is taken into account. Simulated and real-world experiments are carried out to demonstrate the effectiveness of the approach and to verify that the simulated results are accurate and reliable.

Islam, MS, Saha, SC, Gemci, T, Yang, IA, Sauret, E & Gu, YT 2018, 'Polydisperse Microparticle Transport and Deposition to the Terminal Bronchioles in a Heterogeneous Vasculature Tree', Scientific Reports, vol. 8, no. 1.
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AbstractThe atmospheric particles from different sources, and the therapeutic particles from various drug delivery devices, exhibit a complex size distribution, and the particles are mostly polydisperse. The limited available in vitro, and the wide range of in silico models have improved understanding of the relationship between monodisperse particle deposition and therapeutic aerosol transport. However, comprehensive polydisperse transport and deposition (TD) data for the terminal airways is still unavailable. Therefore, to benefit future drug therapeutics, the present numerical model illustrates detailed polydisperse particle TD in the terminal bronchioles for the first time. Euler-Lagrange approach and Rosin-Rammler diameter distribution is used for polydisperse particles. The numerical results show higher deposition efficiency (DE) in the right lung. Specifically, the larger the particle diameter (dp > 5 μm), the higher the DE at the bifurcation area of the upper airways is, whereas for the smaller particle (dp < 5 μm), the DE is higher at the bifurcation wall. The overall deposition pattern shows a different deposition hot spot for different diameter particle. These comprehensive lobe-specific polydisperse particle deposition studies will increase understanding of actual inhalation for particle TD, which could potentially increase the efficiency of pharmaceutical aerosol delivery at the targeted position of the terminal airways.

Jordaan, J, Punzet, S, Melnikov, A, Sanches, A, Oberst, S, Marburg, S & Powell, DA 2018, 'Measuring monopole and dipole polarizability of acoustic meta-atoms', Applied Physics Letters, vol. 113, no. 22, pp. 224102-224102.
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We present a method to extract monopole and dipole polarizability from experimental measurements of two-dimensional acoustic meta-atoms. In contrast to extraction from numerical results, this enables all second-order effects and uncertainties in material properties to be accounted for. We apply the technique to 3D-printed labyrinthine meta-atoms of a variety of geometries. We show that the polarizability of structures with a shorter acoustic path length agrees well with numerical results. However, those with longer path lengths suffer strong additional damping, which we attribute to the strong viscous and thermal losses in narrow channels.

Kuruneru, STW, Sauret, E, Saha, SC & Gu, Y 2018, 'Coupled CFD-DEM simulation of oscillatory particle-laden fluid flow through a porous metal foam heat exchanger: Mitigation of particulate fouling', Chemical Engineering Science, vol. 179, pp. 32-52.
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Lacava, M, Camargo, A, Garcia, LF, Benamú, MA, Santana, M, Fang, J, Wang, X & Blamires, SJ 2018, 'Web building and silk properties functionally covary among species of wolf spider', Journal of Evolutionary Biology, vol. 31, no. 7, pp. 968-978.
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AbstractAlthough phylogenetic studies have shown covariation between the properties of spider major ampullate (MA) silk and web building, both spider webs and silks are highly plastic so we cannot be sure whether these traits functionally covary or just vary across environments that the spiders occupy. As MaSp2‐like proteins provide MA silk with greater extensibility, their presence is considered necessary for spider webs to effectively capture prey. Wolf spiders (Lycosidae) are predominantly non‐web building, but a select few species build webs. We accordingly collected MA silk from two web‐building and six non‐web‐building species found in semirural ecosystems in Uruguay to test whether the presence of MaSp2‐like proteins (indicated by amino acid composition, silk mechanical properties and silk nanostructures) was associated with web building across the group. The web‐building and non‐web‐building species were from disparate subfamilies so we estimated a genetic phylogeny to perform appropriate comparisons. For all of the properties measured, we found differences between web‐building and non‐web‐building species. A phylogenetic regression model confirmed that web building and not phylogenetic inertia influences silk properties. Our study definitively showed an ecological influence over spider silk properties. We expect that the presence of the MaSp2‐like proteins and the subsequent nanostructures improves the mechanical performance of silks within the webs. Our study furthers our understanding of spider web and silk co‐evolution and the ecological implications of spider silk properties.

Li, H, Luo, Z, Gao, L & Qin, Q 2018, 'Topology optimization for concurrent design of structures with multi-patch microstructures by level sets', Computer Methods in Applied Mechanics and Engineering, vol. 331, pp. 536-561.
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© 2017 Elsevier B.V. This paper focuses on the novel concurrent design for cellular structures consisting of multiple patches of material microstructures using a level set-based topological shape optimization method. The macro structure is featured with the configuration of a cluster of non-uniformly distributed patches, while each patch hosts a number of identical material microstructures. At macro scale, a discrete element density based approach is presented to generate an overall structural layout involving different groups of discrete element densities. At micro scale, each macro element is regarded as an individual microstructure with a discrete intermediate density. Hence, all the macro elements with the same discrete densities (volume fractions) are represented by a unique microstructure. The representative microstructures corresponding to different density groups are topologically optimized by incorporating the numerical homogenization approach into a parametric level set method. The multiscale concurrent designs are integrated into a uniform optimization procedure, so as to optimize both topologies for the macrostructure and its microstructures, as well as locations of the microstructures in the design space. Numerical examples demonstrate that the proposed method can substantially improve the structural performance with an affordable computation and manufacturing cost.

Li, H, Luo, Z, Gao, L & Walker, P 2018, 'Topology optimization for functionally graded cellular composites with metamaterials by level sets', Computer Methods in Applied Mechanics and Engineering, vol. 328, pp. 340-364.
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© 2017 Elsevier B.V. The application of auxetic composites in practice often relies on a compromise between properties as auxetics are mostly too porous (not dense enough or not stiff enough) to bear structural loads. Hence, the focus of this paper is topological design optimization of new functionally graded cellular composites with auxetics using a level set method. Firstly, a new hierarchical multi-scale formulation is developed to account for both the auxetic behavior of the microstructure and the stiffness of the macrostructure. The composite, comprising multiple layers of periodic microstructures, is tailored to have functionally graded properties for stiffness and auxetic behaviors, subject to volumetric gradient constraints. Secondly, the microstructures underpinning composite layers are topologically designed under the consideration of boundary and loading conditions of the macrostructure. Finally, a level set method is applied to evolve the shape and topology of the microstructure for each layer, with the numerical homogenization method to evaluate the effective properties of the microstructures. Several numerical examples are used to demonstrate the effectiveness of the proposed method. It can be seen that such composites systematically gear together the features of the functionally graded materials, cellular composites, and metamaterials towards a new kind of man-made composites.

Li, H, Öchsner, A, Yarlagadda, PKDV, Xiao, Y, Furushima, T, Wei, D, Jiang, Z & Manabe, K-I 2018, 'A new constitutive analysis of hexagonal close-packed metal in equal channel angular pressing by crystal plasticity finite element method', Continuum Mechanics and Thermodynamics, vol. 30, no. 1, pp. 69-82.
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© 2017, Springer-Verlag GmbH Germany. Most of hexagonal close-packed (HCP) metals are lightweight metals. With the increasing application of light metal products, the production of light metal is increasingly attracting the attentions of researchers worldwide. To obtain a better understanding of the deformation mechanism of HCP metals (especially for Mg and its alloys), a new constitutive analysis was carried out based on previous research. In this study, combining the theories of strain gradient and continuum mechanics, the equal channel angular pressing process is analyzed and a HCP crystal plasticity constitutive model is developed especially for Mg and its alloys. The influence of elevated temperature on the deformation mechanism of the Mg alloy (slip and twin) is novelly introduced into a crystal plasticity constitutive model. The solution for the new developed constitutive model is established on the basis of the Lagrangian iterations and Newton Raphson simplification.

Liu, D, Yang, L, He, X, Wang, R & Luo, Q 2018, 'Atomistic-scale simulations of mechanical behavior of suspended single-walled carbon nanotube bundles under nanoprojectile impact', Computational Materials Science, vol. 142, pp. 237-243.
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Liu, W, Yan, X, Huang, S, Yang, C & Wang, G 2018, 'Advanced Control for Singular Systems with Applications', Mathematical Problems in Engineering, vol. 2018, pp. 1-2.
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Luo, L, Jiang, Z, Wei, D, Wang, X, Zhou, C & Huang, Q 2018, 'Micro-hydromechanical deep drawing of metal cups with hydraulic pressure effects', Frontiers of Mechanical Engineering, vol. 13, no. 1, pp. 66-73.
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© 2018, Higher Education Press and Springer-Verlag GmbH Germany. Micro-metal products have recently enjoyed high demand. In addition, metal microforming has drawn increasing attention due to its net-forming capability, batch manufacturing potential, high product quality, and relatively low equipment cost. Micro-hydromechanical deep drawing (MHDD), a typical microforming method, has been developed to take advantage of hydraulic force. With reduced dimensions, the hydraulic pressure development changes; accordingly, the lubrication condition changes from the macroscale to the microscale. A Voronoi-based finite element model is proposed in this paper to consider the change in lubrication in MHDD according to open and closed lubricant pocket theory. Simulation results agree with experimental results concerning drawing force. Changes in friction significantly affect the drawing process and the drawn cups. Moreover, defined wrinkle indexes have been shown to have a complex relationship with hydraulic pressure. High hydraulic pressure can increase the maximum drawing ratio (drawn cup height), whereas the surface finish represented by the wear is not linearly dependent on the hydraulic pressure due to the wrinkles.

Ma, H, Xiong, R, Wang, Y, Kodagoda, S & Shi, L 2018, 'Towards open-set semantic labeling in 3D point clouds : Analysis on the unknown class', Neurocomputing, vol. 275, pp. 1282-1294.
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© 2017 Elsevier B.V. There has been a growing interest in the research of semantic labeling on scenes represented by 3D point clouds. A fundamental issue that has been largely ignored is the unavoidable presence of unknown objects and the lack of effective ways of dealing with them. Traditional methods usually label unknown objects as one of the pre-trained classes which is either a meaningful target class or a defined unknown class that collectively refers to all uninterested objects. Due to the fact that the class of unknown in essence is a collection of many unseen or uninterested classes, in which the in-class variation is significant and less manageable. It is challenging to solve the unknown problem in a pre-trained manner. In order to advance the research on semantic labeling with the presence of unknown objects, this study investigates the feasibility of adopting an open-set approach, i.e. train a model without unknown objects and reject them accurately in the test. In this paper, we propose a method that exploits the conflict of different labeling results in order to withstand the negative effect of unknown objects. The proposed framework relies on a Conditional Random Field (CRF) to capture inherent spatial relationships and appearance similarities between objects, and employs a Probability of Inclusion Support Vector Machine (P I SVM) to estimate an unknown likelihood for each training class. The probabilistic outputs from both CRF and P I SVM are then proposed to be combined under the Dempster Shafer theory for conflict measurement and unkno wn rejection. The novelty lies in that the method encodes both contextual constrains and unknown likelihood for performance enhancement. Comprehensive experimental results on publicly available data sets are presented to show the negative effects of unknown objects and the improvements on labeling accuracy achieved by the proposed method.

Man, X, Liu, T, Xia, B, Luo, Z, Xie, L & Liu, J 2018, 'Space-coiling fractal metamaterial with multi-bandgaps on subwavelength scale', Journal of Sound and Vibration, vol. 423, pp. 322-339.
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© 2018 Elsevier Ltd Acoustic metamaterials are remarkably different from conventional materials, as they can flexibly manipulate and control the propagation of sound waves. Unlike the locally resonant metamaterials introduced in earlier studies, we designed an ultraslow artificial structure with a sound speed much lower than that in air. In this paper, the space-coiling approach is proposed for achieving artificial metamaterial for extremely low-frequency airborne sound. In addition, the self-similar fractal technique is utilized for designing space-coiling Mie-resonance-based metamaterials (MRMMs) to obtain a band-dispersive spectrum. The band structures of two-dimensional (2D) acoustic metamaterials with different fractal levels are illustrated using the finite element method. The low-frequency bandgap can easily be formed, and multi-bandgap properties are observed in high-level fractals. Furthermore, the designed MRMMs with higher order fractal space coiling shows a good robustness against irregular arrangement. Besides, the proposed artificial structure was found to modify and control the radiation field arbitrarily. Thus, this work provides useful guidelines for the design of acoustic filtering devices and acoustic wavefront shaping applications on the subwavelength scale.

Mazraeh, AE, Babayan, M, Yari, M, Sefidan, AM & Saha, SC 2018, 'Theoretical study on the performance of a solar still system integrated with PCM-PV module for sustainable water and power generation', Desalination, vol. 443, pp. 184-197.
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© 2018 Elsevier B.V. Current paper studies a new solar still system integrated with semitransparent photovoltaic, evacuated tube collectors and phase change materials. Mathematical modeling has been accomplished based on energy/exergy balance equations to investigate the effects of various PCM-PV modules, basin water depth and tube numbers on the system thermal and electrical performance. The system is examined in terms of distilled water production, electricity generation, and energy/exergy efficiencies. Variations of distilled water, system temperature, generated electricity power and energy/exergy outputs and efficiencies over time are presented for various effective parameters. Considering obtained results, while PV type does not affect distilled water, it is the dominant parameter on generated electrical power. Tube number as another important parameter, improves the distilled water production, however, it influences the energy/exergy efficiencies in an inverse way. Presence of PCM, improves the energy efficiency, but has negligible effect on the exergy efficiency. The highest amount of distilled water during a day is calculated for the water basin depth of 0.03 m and 30 tube number with paraffin wax PCM type (4.5503 kg/m2·day) which is 20.32% more than the case without PCM. Moreover, maximum diurnal energy/exergy efficiencies are reported 17.93% and 6.95% for water depth of 0.03 m and 10 tubes with PCM.

Molla, MM, Haque, MJ, Khan, MAI & Saha, SC 2018, 'GPU Accelerated Multiple-Relaxation-Time Lattice Boltzmann Simulation of Convective Flows in a Porous Media', Frontiers in Mechanical Engineering, vol. 4, p. 15.
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A two-dimensional (2D) multiple-relaxation-time (MRT)-lattice Boltzmann method (LBM) is used for porous media with the Brinkman–Forchheimer extended Darcy model to investigate the natural and mixed convection flows in a square cavity. This Brinkman–Forchheimer model is directly applied by using the forcing moments as a source term. A Tesla K40 NVIDIA graphics card has been used for the present graphics processing unit (GPU) parallel computing via compute unified device architecture (CUDA) C platform. The numerical results are presented in terms of velocity, temperature, streamlines, isotherms, and local and average Nusselt numbers. For the wide range of Rayleigh numbers, (Ra = 103 to 1010), Reynolds numbers, Darcy numbers, and porosities, the average Nusselt number is compared with the available results computed by finite element method (FEM) and single-relaxation-time (SRT) lattice Boltzmann method-LBM and, showing great compliance. The results are also validated with the previous experimental results. The simulations speed up to a maximum of 144x using CUDA C in GPU compared with the time of FORTRAN 90 code using a single core CPU simulation.

Oberst, S & Tuttle, S 2018, 'Nonlinear dynamics of thin-walled elastic structures for applications in space', Mechanical Systems and Signal Processing, vol. 110, pp. 469-484.
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© 2018 Elsevier Ltd Driven by the need for multi-functionality and increasing demands for low mass and compact-stowing, unfolding, self-deploying or –morphing smart mechanical structures have become popular space engineering designs for flexible appendages. Extensive research has been conducted on the use of tape springs as hinge deployment mechanisms for space booms, solar sails, or optical membranes or directly for used as antennas. However, the vibrational behaviour of tape springs and its related dynamics have rarely been addressed in detail, even though missions are underway with similarly flexible appendages installed. By conducting quasi-static bending tests on a tape spring antenna, we evidence hysteresis behaviours in both the opposite- and equal sense bending directions. Apart from the well-known snap-through buckling, the structure exhibits torsional buckling in the equal sense bending direction before collapsing. Micro-vibrational excitation triggers nonlinear jump phenomena and the period-doubling route to chaos. Using a computational tape spring model and simplified environmental loads similar to those encountered in near-Earth orbits, coupling between the first bending and torsional modes generates a dynamic instability which is predicted by a complex eigenvalue analysis step. The current study highlights that high perturbation sensitivity and system-inherent nonlinearities can lead to stability issues. In the course of designing a spacecraft with thin-walled appendages, system-level trade-offs are routinely performed. Since it is unclear how severely the vibrations of flexible appendages might affect their proper functioning or the control of the spacecraft, it is of paramount importance to validate experimentally thin-walled structures thoroughly for their dynamic and stability behaviours.

Oberst, S, Baetz, J, Campbell, G, Lampe, F, Lai, JCS, Hoffmann, N & Morlock, M 2018, 'Vibro-acoustic and nonlinear analysis of cadavric femoral bone impaction in cavity preparations', International Journal of Mechanical Sciences, vol. 144, pp. 739-745.
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© 2018 Elsevier Ltd Owing to an ageing population, the impact of unhealthy lifestyle, or simply congenital or gender specific issues (dysplasia), degenerative bone and joint disease (osteoarthritis) at the hip pose an increasing problem in many countries. Osteoarthritis is painful and causes mobility restrictions; amelioration is often only achieved by replacing the complete hip joint in a total hip arthroplasty (THA). Despite significant orthopaedic progress related to THA, the success of the surgical process relies heavily on the judgement, experience, skills and techniques used of the surgeon. One common way of implanting the stem into the femur is press fitting uncemented stem designs into a prepared cavity. By using a range of compaction broaches, which are impacted into the femur, the cavity for the implant is formed. However, the surgeon decides whether to change the size of the broach, how hard and fast it is impacted or when to stop the excavation process, merely based on acoustic, haptic or visual cues which are subjective. It is known that non-ideal cavity preparations increase the risk of peri-prosthetic fractures especially in elderly people. This study reports on a simulated hip replacement surgery on a cadaver and the analysis of impaction forces and the microphone signals during compaction. The recorded transient signals of impaction forces and acoustic pressures (≈ 80 µs–2 ms) are statistically analysed for their trend, which shows increasing heteroscedasticity in the force-pressure relationship between broach sizes. TIKHONOV regularisation, as inverse deconvolution technique, is applied to calculate the acoustic transfer functions from the acoustic responses and their mechanical impacts. The extracted spectra highlight that system characteristics altered during the cavity preparation process: in the high-frequency range the number of resonances increased with impacts and broach size. By applying nonlinear time series analysis the syste...

Oberst, S, Lai, JCS & Evans, TA 2018, 'Key physical wood properties in termite foraging decisions', Journal of The Royal Society Interface, vol. 15, no. 149, pp. 20180505-20180505.
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As eusocial and wood-dwelling insects, termites have been shown to use vibrations to assess their food, to eavesdrop on competitors and predators and to warn nest-mates. Bioassay choice experiments used to determine food preferences in animals often consider single factors only but foraging decisions can be influenced by multiple factors such as the quantity and quality of the food and the wood as a medium for communication. A statistical analysis framework is developed here to design a single bioassay experiment to study multifactorial foraging choice (Pinus radiata) in the basal Australian termite speciesCoptotermes(C.)acinaciformis(Isoptera: Rhinotermitidae). By employing a correlation analysis, 17 measured physical properties of 1417Pinus radiataveneer discs were reduced to five key material properties: density, moisture absorption, early wood content, first resonance frequency and damping. By applying a fuzzyc-means clustering technique, these veneer discs were optimally paired for treatment and control trials to study food preference by termites based on these five key material properties. A multifactorial analysis of variance was compared to a permutation analysis of the results indicating for the first time thatC. acinaciformistakes into account multiple factors when making foraging decisions.C. acinaciformisprefer denser wood with large early wood content, preferably humid and highly damped. Results presented here have practical implications for food choice experiments and for studies concerned with communication in termites as well as their ecology and coevolution with trees as their major food source.

Oberst, S, Niven, RK, Lester, DR, Ord, A, Hobbs, B & Hoffmann, N 2018, 'Detection of unstable periodic orbits in mineralising geological systems', Chaos: An Interdisciplinary Journal of Nonlinear Science, vol. 28, no. 8, pp. 085711-085711.
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Worldwide, mineral exploration is suffering from rising capital costs, due to the depletion of readily recoverable reserves and the need to discover and assess more inaccessible or geologically complex deposits. For gold exploration, this problem is particularly acute. We propose an innovative approach to mineral exploration and orebody characterisation, based on the analysis of geological core data as a spatial dynamical system, using the mathematical tools of dynamical system analysis. This approach is highly relevant for orogenic gold deposits, which—in contrast to systems formed at chemical equilibrium—exhibit many features of nonlinear dynamical systems, including episodic fluctuations on various length and time scales. Feedback relationships between thermo-chemical and deformation processes produce recurrent fluid temperatures and pressures and the deposition of vein-filling minerals such as pyrite and gold. We therefore relax the typical assumption of chemical equilibrium and analyse the underlying processes as aseismic, non-adiabatic, and inherent to a hydrothermal, nonlinear dynamical open-flow chemical reactor. These processes are approximated using the Gray-Scott model of reaction-diffusion as a complex toy system, which captures some of the features of the underlying mineralisation processes, including the spatiotemporal Turing patterns of unsteady chemical reactions. By use of this analysis, we demonstrate the capability of recurrence plots, recurrence power spectra, and recurrence time probabilities to detect underlying unstable periodic orbits as one sign of deterministic dynamics and their robustness for the analysis of data contaminated by noise. Recurrence plot based quantification is then applied to three mineral concentrations in the core data from the Sunrise Dam gold deposit in the Yilgarn region of Western Australia. Using a moving window, we reveal the episodic recurring low-dimensional dynamic structures and the period d...

Oberst, S, Tuttle, SL, Griffin, D, Lambert, A & Boyce, RR 2018, 'Experimental validation of tape springs to be used as thin-walled space structures', Journal of Sound and Vibration, vol. 419, pp. 558-570.
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© 2018 Elsevier Ltd With the advent of standardised launch geometries and off-the-shelf payloads, space programs utilising nano-satellite platforms are growing worldwide. Thin-walled, flexible and self-deployable structures are commonly used for antennae, instrument booms or solar panels owing to their lightweight, ideal packaging characteristics and near zero energy consumption. However their behaviour in space, in particular in Low Earth Orbits with continually changing environmental conditions, raises many questions. Accurate numerical models, which are often not available due to the difficulty of experimental testing under 1g-conditions, are needed to answer these questions. In this study, we present on-earth experimental validations, as a starting point to study the response of a tape spring as a representative of thin-walled flexible structures under static and vibrational loading. Material parameters of tape springs in a singly (straight, open cylinder) and a doubly curved design, are compared to each other by combining finite element calculations, with experimental laser vibrometry within a single and multi-stage model updating approach. While the determination of the Young's modulus is unproblematic, the damping is found to be inversely proportional to deployment length. With updated material properties the buckling instability margin is calculated using different slenderness ratios. Results indicate a high sensitivity of thin-walled structures to miniscule perturbations, which makes proper experimental testing a key requirement for stability prediction on thin-elastic space structures. The doubly curved tape spring provides closer agreement with experimental results than a straight tape spring design.

Patten, T, Martens, W & Fitch, R 2018, 'Monte Carlo planning for active object classification', Autonomous Robots, vol. 42, no. 2, pp. 391-421.
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© 2017, Springer Science+Business Media New York. Classifying objects in complex unknown environments is a challenging problem in robotics and is fundamental in many applications. Modern sensors and sophisticated perception algorithms extract rich 3D textured information, but are limited to the data that are collected from a given location or path. We are interested in closing the loop around perception and planning, in particular to plan paths for better perceptual data, and focus on the problem of planning scanning sequences to improve object classification from range data. We formulate a novel time-constrained active classification problem and propose solution algorithms that employ a variation of Monte Carlo tree search to plan non-myopically. Our algorithms use a particle filter combined with Gaussian process regression to estimate joint distributions of object class and pose. This estimator is used in planning to generate a probabilistic belief about the state of objects in a scene, and also to generate beliefs for predicted sensor observations from future viewpoints. These predictions consider occlusions arising from predicted object positions and shapes. We evaluate our algorithms in simulation, in comparison to passive and greedy strategies. We also describe similar experiments where the algorithms are implemented online, using a mobile ground robot in a farm environment. Results indicate that our non-myopic approach outperforms both passive and myopic strategies, and clearly show the benefit of active perception for outdoor object classification.

Piorkowski, D, Blackledge, TA, Liao, C, Doran, NE, Wu, C, Blamires, SJ & Tso, I 2018, 'Humidity‐dependent mechanical and adhesive properties of Arachnocampa tasmaniensis capture threads', Journal of Zoology, vol. 305, no. 4, pp. 256-266.
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AbstractBioluminescent glow‐worms (Arachnocampa spp.) capture prey in glue‐coated silk capture threads hung from their nests on damp cave and wet forest substrates. In a dry environment, these animals are very susceptible to desiccation as their bodies can become life threateningly dry and their silk has been anecdotally observed to become non‐sticky. Water has a plasticizing effect on the structural proteins of several invertebrate silks, including those used in caddisfly nets, mussel byssus and spider webs. Moreover, water facilitates interfacial adhesion by spreading adhesive biomolecules in functionally analogous velvet worm slime and spider silk glue. We tested the effects of water on the mechanics and adhesion of Arachnocampa tasmaniensis capture threads sampled within damp caves. We found that threads tested at high humidity were three times more compliant and over 10‐fold more extensible than those tested at low humidity (30% RH). We also found the threads to be significantly more adhesive in high humidity with force at detachment increasing two orders of magnitude and work of adhesion increasing by five orders of magnitude compared to threads tested at low humidity. Our results unequivocally demonstrate that A. tasmaniensis capture thread functionality is dependent upon exposure to high humidity. Our results both confirm previous reports and indicate that the foraging habitat of these animals is restricted to caves and cave‐like environments, such as wet forests.

Piorkowski, D, Blamires, SJ, Doran, NE, Liao, C, Wu, C & Tso, I 2018, 'Ontogenetic shift toward stronger, tougher silk of a web‐building, cave‐dwelling spider', Journal of Zoology, vol. 304, no. 2, pp. 81-89.
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AbstractAnimal morphological traits may vary across life stages. Web‐building spiders are diverse insectivores that can display ontogenetic shifts in the design and properties of their webs. Nevertheless, we know little about how a critical component of their webs, major ampullate silk (MAS), varies in property across life stages, inferably owing to a difficulty in finding suitable model species. The Tasmanian cave spider Hickmania troglodytes presents as a good model as it is long‐lived and grows to a large body size with overlapping generations. We collected MAS from the webs of different‐sized H. troglodytes and performed tensile tests on MAS fibers collected from their webs to search for shifts in properties over life stages. We found that strength and toughness (i.e. ability to deform and absorb energy) of the MAS increased with spider carapace width and body length. We expect that such a shift in silk performance across life stages has distinctive advantages, including enhanced prey capture capabilities, an improvement in the economy of silk production and ability of the web to support the spider's larger body.

Polwaththe-Gallage, H-N, Sauret, E, Nguyen, N-T, Saha, SC & Gu, Y 2018, 'A novel numerical model to predict the morphological behavior of magnetic liquid marbles using coarse grained molecular dynamics concepts', Physics of Fluids, vol. 30, no. 1, pp. 017105-017105.
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Liquid marbles are liquid droplets coated with superhydrophobic powders whose morphology is governed by the gravitational and surface tension forces. Small liquid marbles take spherical shapes, while larger liquid marbles exhibit puddle shapes due to the dominance of gravitational forces. Liquid marbles coated with hydrophobic magnetic powders respond to an external magnetic field. This unique feature of magnetic liquid marbles is very attractive for digital microfluidics and drug delivery systems. Several experimental studies have reported the behavior of the liquid marbles. However, the complete behavior of liquid marbles under various environmental conditions is yet to be understood. Modeling techniques can be used to predict the properties and the behavior of the liquid marbles effectively and efficiently. A robust liquid marble model will inspire new experiments and provide new insights. This paper presents a novel numerical modeling technique to predict the morphology of magnetic liquid marbles based on coarse grained molecular dynamics concepts. The proposed model is employed to predict the changes in height of a magnetic liquid marble against its width and compared with the experimental data. The model predictions agree well with the experimental findings. Subsequently, the relationship between the morphology of a liquid marble with the properties of the liquid is investigated. Furthermore, the developed model is capable of simulating the reversible process of opening and closing of the magnetic liquid marble under the action of a magnetic force. The scaling analysis shows that the model predictions are consistent with the scaling laws. Finally, the proposed model is used to assess the compressibility of the liquid marbles. The proposed modeling approach has the potential to be a powerful tool to predict the behavior of magnetic liquid marbles serving as bioreactors.

Pupatwibul, P, Banjar, A, Hossain, I, Braun, R & Moulton, B 2018, 'A novel software-defined networking controller: The Distributed Active Information Model (DAIM)', International Journal of Electronics and Telecommunications, vol. 64, no. 2, pp. 209-216.
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This paper presents a new OpenFlow controller: the Distributed Active Information Model (DAIM). The DAIM controller was developed to explore the viability of a logically distributed control plane. It is implemented in a distributed way throughout a software-defined network, at the level of the switches. The method enables local process flows, by way of local packet switching, to be controlled by the distributed DAIM controller (as opposed to a centralised OpenFlow controller). The DAIM ecosystem is discussed with some sample code, together with flowcharts of the implemented algorithms. We present implementation details, a testing methodology, and an experimental evaluation. A performance analysis was conducted using the Cbench open benchmarking tool. Comparisons were drawn with respect to throughput and latency. It is concluded that the DAIM controller can handle a high throughput, while keeping the latency relatively low. We believe the results to date are potentially very interesting, especially in light of the fact that a key feature of the DAIM controller is that it is designed to enable the future development of autonomous local flow process and management strategies.

Qiao, M, Xu, F & Saha, SC 2018, 'Numerical study of the transition to chaos of a buoyant plume from a two-dimensional open cavity heated from below', Applied Mathematical Modelling, vol. 61, pp. 577-592.
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Ragazzon, MRP, Ruppert, MG, Harcombe, DM, Fleming, AJ & Gravdahl, JT 2018, 'Lyapunov Estimator for High-Speed Demodulation in Dynamic Mode Atomic Force Microscopy', IEEE Transactions on Control Systems Technology, vol. 26, no. 2, pp. 765-772.
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Rahman, S, Quin, P, Walsh, T, Vidal-Calleja, T, McPhee, MJ, Toohey, E & Alempijevic, A 2018, 'Preliminary estimation of fat depth in the lamb short loin using a hyperspectral camera', Animal Production Science, vol. 58, no. 8, pp. 1488-1488.
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The objectives of the present study were to describe the approach used for classifying surface tissue, and for estimating fat depth in lamb short loins and validating the approach. Fat versus non-fat pixels were classified and then used to estimate the fat depth for each pixel in the hyperspectral image. Estimated reflectance, instead of image intensity or radiance, was used as the input feature for classification. The relationship between reflectance and the fat/non-fat classification label was learnt using support vector machines. Gaussian processes were used to learn regression for fat depth as a function of reflectance. Data to train and test the machine learning algorithms was collected by scanning 16 short loins. The near-infrared hyperspectral camera captured lines of data of the side of the short loin (i.e. with the subcutaneous fat facing the camera). Advanced single-lens reflex camera took photos of the same cuts from above, such that a ground truth of fat depth could be semi-automatically extracted and associated with the hyperspectral data. A subset of the data was used to train the machine learning model, and to test it. The results of classifying pixels as either fat or non-fat achieved a 96% accuracy. Fat depths of up to 12 mm were estimated, with an R2 of 0.59, a mean absolute bias of 1.72 mm and root mean square error of 2.34 mm. The techniques developed and validated in the present study will be used to estimate fat coverage to predict total fat, and, subsequently, lean meat yield in the carcass.

Schmitt, J, Wiegand, M & Deuse, J 2018, 'Qualitätsbasierte Auftrags-zuordnung', Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 113, no. 4, pp. 191-194.
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Kurzfassung Die Gewährleistung durchgängiger Qualität ist für Unternehmen ein wesentlicher Wettbewerbsfaktor. Die Qualitätsanforderungen des Kunden an ein Produkt können dabei sehr unterschiedlich sein. Im Rahmen dieses Fachbeitrags wird ein Konzept zur optimalen Zuordnung von Zwischenprodukten zu Kundenaufträgen aus dem Auftragsbestand auf Basis von Qualitätsprognosen vorgestellt. Ziel des Konzepts ist die Reduzierung von Ausschuss und Lieferterminabweichungen.

Sharwood, LN, Adams, S, Blaszkow, T & Eager, D 2018, 'Increasing injuries as trampoline parks expand within Australia: a call for mandatory standards', Australian and New Zealand Journal of Public Health, vol. 42, no. 2, pp. 153-156.
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© 2018 The Authors Objective: To quantify an apparent increase in indoor trampoline park related injuries in children and young people across Australia, and to understand the implications for current regulatory standards. Methods: Retrospective analyses of three state-based Injury Surveillance databases, identifying children and adolescents presenting to emergency departments between the years 2005 and 2017, who had sustained injuries during trampolining activity at an indoor trampoline park. Results: Across the three datasets, 487 cases were identified. No cases were recorded prior to 2012, the year the first indoor trampoline park opened. At least half occurred among those aged 10–14 years. In Victoria, 58% were male, with 52% in Queensland and 60% in Western Australia being male, respectively. Hospital admission rates in these states were 15%, 11.7% and 14.5%, respectively. The most frequent injury types were dislocations, sprains and strains, followed by fractures, with some head and spinal injuries. Conclusions: Across several states in Australia, the incidence of indoor trampoline park related injuries is concerning, as these venues are increasing in number. Some injuries can be serious and result in lifelong disability for children or adolescents. Implications for public health: National safety standards that apply to indoor trampoline park operators are not currently mandatory; injury prevention efforts would be assisted if such standards were mandatory.

SHI, G, ZHU, LIN & WEI, D 2018, 'A NEW PREDICTION APPROACH FOR THE STRUCTURAL FATIGUE LIFE BASED ON MULTI-FACTOR CORRECTION', Surface Review and Letters, vol. 25, no. 05, pp. 1850095-1850095.
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As the phenomenon of fatigue damage is a common failure mode of equipment, the reliability evaluation and life prediction have become a hot-spot. The precise prediction of fatigue life in the initiation stage has become necessary. The common prediction study for structural fatigue life takes less influence factors into consideration. The common prediction results of fatigue life cannot be quantitatively corrected by the influence factors at the same time. This paper presents a research on the prediction approach for structural fatigue life based on the multi-factor correction. The influence of some factors on the fatigue life was analyzed and the prediction approach for structural fatigue life based on multi-factor correction was raised. Then the fatigue life of axle housing was predicted by using the corrected approach, as the case study. Moreover, the result predicted by the local stress–strain approach and the experimental data were used to verify the accuracy of the corrected approach. It can be clearly demonstrated by the results that the corrected prediction approach can be used to achieve the precision fatigue life for engineering structures. Further, it is also a prediction approach endowed with engineering application prospects.

Shiozaki, T & Dissanayake, G 2018, 'Eliminating Scale Drift in Monocular SLAM Using Depth From Defocus', IEEE Robotics and Automation Letters, vol. 3, no. 1, pp. 581-587.
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This letter presents a novel approach to correct errors caused by accumulated scale drift in monocular SLAM. It is shown that the metric scale can be estimated using information gathered through monocular SLAM and image blur due to defocus. A nonlinear least squares optimization problem is formulated to integrate depth estimates from defocus to monocular SLAM. An algorithm to process the output keyframe and feature location estimates generated by a monocular SLAM algorithm to correct for scale drift at selected local regions of the environment is presented. The proposed algorithm is experimentally evaluated by processing the output of ORB-SLAM to obtain accurate metric scale maps from a monocular camera without any prior knowledge about the scene.

Siedelhofer, C, Schallow, J, Wolf, P, Mayer, S & Deuse, J 2018, 'Simulationsbasierte Rekonfigurationsplanung flexibler Montagesysteme', Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 113, no. 4, pp. 216-219.
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Kurzfassung Die Rekonfiguration flexibler Montagesysteme erfolgt in immer kürzeren Zyklen, was zu einem erhöhten Planungsaufwand führt. Zur Unterstützung der Montageplanung und Erhöhung der Planungs-qualität wird eine Planungssystematik für die Rekonfiguration entwickelt. Die Planungsmethode basiert auf einem integrierten, digitalen Planungswerkzeug, welches ein PLM-System und ein Simulationswerkzeug konsistent verknüpft.

Solanes, JE, Gracia, L, Muñoz-Benavent, P, Valls Miro, J, Carmichael, MG & Tornero, J 2018, 'Human–robot collaboration for safe object transportation using force feedback', Robotics and Autonomous Systems, vol. 107, pp. 196-208.
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© 2018 Elsevier B.V. This work presents an approach based on multi-task, non-conventional sliding mode control and admittance control for human–robot collaboration aimed at handling applications using force feedback. The proposed robot controller is based on three tasks with different priority levels in order to cooperatively perform the safe transportation of an object with a human operator. In particular, a high-priority task is developed using non-conventional sliding mode control to guarantee safe reference parameters imposed by the task, e.g., keeping a load at a desired orientation (to prevent spill out in the case of liquids, or to reduce undue stresses that may compromise fragile items). Moreover, a second task based on a hybrid admittance control algorithm is used for the human operator to guide the robot by means of a force sensor located at the robot tool. Finally, a third low-priority task is considered for redundant robots in order to use the remaining degrees of freedom of the robot to achieve a pre-set secondary goal (e.g., singularity avoidance, remaining close to a homing configuration for increased safety, etc.) by means of the gradient projection method. The main advantages of the proposed method are robustness and low computational cost. The applicability and effectiveness of the proposed approach are substantiated by experimental results using a redundant 7R manipulator: the Sawyer collaborative robot.

Song, J, Wang, J, Zhao, L, Huang, S & Dissanayake, G 2018, 'Dynamic Reconstruction of Deformable Soft-Tissue With Stereo Scope in Minimal Invasive Surgery', IEEE Robotics and Automation Letters, vol. 3, no. 1, pp. 155-162.
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© 2016 IEEE. In minimal invasive surgery, it is important to rebuild and visualize the latest deformed shape of soft-tissue surfaces to mitigate tissue damages. This letter proposes an innovative Simultaneous localization and mapping (SLAM) algorithm for deformable dense reconstruction of surfaces using a sequence of images from a stereoscope. We introduce a warping field based on the embedded deformation nodes with three-dimensional (3-D) shapes recovered from consecutive pairs of stereo images. The warping field is estimated by deforming the last updated model to the current live model. Our SLAM system can incrementally build a live model by progressively fusing new observations with vivid accurate texture; estimate the deformed shape of unobserved region with the principle as-rigid-as-possible; show the consecutive shape of models; and estimate the current relative pose between the soft-tissue and the scope. In-vivo experiments with publicly available datasets demonstrate that the 3-D models can be incrementally built for different soft-tissues with different deformations from sequences of stereo images obtained by laparoscopes. Results show the potential clinical application of our SLAM system for providing surgeon useful shape and texture information in minimal invasive surgery.

Song, J, Wang, J, Zhao, L, Huang, S & Dissanayake, G 2018, 'MIS-SLAM: Real-Time Large-Scale Dense Deformable SLAM System in Minimal Invasive Surgery Based on Heterogeneous Computing', IEEE Robotics and Automation Letters, vol. 3, no. 4, pp. 4068-4075.
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© 2016 IEEE. Real-time simultaneous localization and dense mapping is very helpful for providing virtual reality and augmented reality for surgeons or even surgical robots. In this letter, we propose MIS-SLAM: A complete real-time large-scale dense deformable SLAM system with stereoscope in minimal invasive surgery (MIS) based on heterogeneous computing by making full use of CPU and GPU. Idled CPU is used to perform ORB-SLAM for providing robust global pose. Strategies are taken to integrate modules from CPU and GPU. We solved the key problem raised in the previous work, that is, fast movement of scope and blurry images make the scope tracking fail. Benefiting from improved localization, MIS-SLAM can achieve large-scale scope localizing and dense mapping in real time. It transforms and deforms current model and incrementally fuses new observation while keeping vivid texture. In-vivo experiments conducted on publicly available datasets presented in the form of videos demonstrate the feasibility and practicality of MIS-SLAM for potential clinical purpose.

Stender, M, Tiedemann, M, Hoffmann, N & Oberst, S 2018, 'Impact of an irregular friction formulation on dynamics of a minimal model for brake squeal', Mechanical Systems and Signal Processing, vol. 107, pp. 439-451.
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Friction-induced vibrations are of major concern in the design of reliable, efficient and comfortable technical systems. Well-known examples for systems susceptible to self-excitation can be found in fluid structure interaction, disk brake squeal, rotor dynamics, hip implants noise and many more. While damping elements and amplitude reduction are well-understood in linear systems, nonlinear systems and especially self-excited dynamics still constitute a challenge for damping element design. Additionally, complex dynamical systems exhibit deterministic chaotic cores which add severe sensitivity to initial conditions to the system response. Especially the complex friction interface dynamics remain a challenging task for measurements and modeling. Today, mostly simple and regular friction models are investigated in the field of self-excited brake system vibrations. This work aims at investigating the effect of high-frequency irregular interface dynamics on the nonlinear dynamical response of a self-excited structure. Special focus is put on the characterization of the system response time series. A low-dimensional minimal model is studied which features self-excitation, gyroscopic effects and friction-induced damping. Additionally, the employed friction formulation exhibits temperature as inner variable and superposed chaotic fluctuations governed by a Lorenz attractor. The time scale of the irregular fluctuations is chosen one order smaller than the overall system dynamics. The influence of those fluctuations on the structural response is studied in various ways, i.e. in time domain and by means of recurrence analysis. The separate time scales are studied in detail and regimes of dynamic interactions are identified. The results of the irregular friction formulation indicate dynamic interactions on multiple time scales, which trigger larger vibration amplitudes as compared to regular friction formulations conventionally studied in the field of friction-induced vibr...

Suseno, Y, Laurell, C & Sick, N 2018, 'Assessing value creation in digital innovation ecosystems: A Social Media Analytics approach', The Journal of Strategic Information Systems, vol. 27, no. 4, pp. 335-349.
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Taghilou, M, Sefidan, AM, Sojoudi, A & Saha, SC 2018, 'Solid-liquid phase change investigation through a double pipe heat exchanger dealing with time-dependent boundary conditions', Applied Thermal Engineering, vol. 128, pp. 725-736.
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© 2017 Elsevier Ltd The use of phase change materials has been seriously recommended due to their high capacity of energy saving and delivering arising from phase change process. In addition, a constant temperature of melting or freezing provides a desirable condition to transfer a large amount of heat in a low-temperature fluctuation. This work attempts to present a numerical study to simulate the solid-liquid phase change considering a double pipe heat exchanger dealing with time-dependent boundary conditions. For this reason, a time dependent boundary condition of the third kind is applied. In a condition which the amplitude and periodicity of both bulk temperature and heat transfer coefficient (HTC) are varying in the sinusoidal form. The PCM container involves two separate sections to insert two different PCMs of RT28HC and RT35. In addition, in order to make up for the low thermal conductivity of PCMs, a porous medium with high thermal conductivity is located in PCM containers. Numerical model benefits the enthalpy-porosity approach based on the finite volume method, which models the phase change in the fixed grid domain. Moreover, in order to accurate simulation, fluid flow arising from Boussinesq approximation in the liquid phase is also considered using PISO algorithm. According to the results, the arrangement of RT35 in section A and RT28HC in section B accelerates the system response to the boundary oscillation. In addition, increasing the periodicity of the bulk temperature variation increases the amount of phase changing process in both sections while varying the same parameter of HTC does not influence the liquid fraction of PCMs considerably.

Thiyagarajan, K, Kodagoda, S, Ranasinghe, R, Vitanage, D & Iori, G 2018, 'Robust sensing suite for measuring temporal dynamics of surface temperature in sewers', Scientific Reports, vol. 8, no. 1.
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AbstractSewerage systems are paramount underground infrastructure assets for any nation. In most cities, they are old and have been exposed to significant microbial induced corrosion. It is a serious global problem as they pose threats to public health and economic repercussions to water utilities. For managing sewer assets efficaciously, it is vital to predict the rate of corrosion. Predictive models of sewer corrosion incorporate concrete surface temperature measurements as an observation. However, currently, it has not been fully utilized due to unavailability of a proven sensor. This study reports the feasibility of infrared radiometer for measuring the surface temperature dynamics in the aggressive sewer conditions. The infrared sensor was comprehensively evaluated in the laboratory at different environmental conditions. Then, the sensor suite was deployed in a Sydney based sewer for three months to perform continuous measurements of surface temperature variations. The field study revealed the suitability of the developed sensor suite for non-contact surface temperature measurements in hostile sewer conditions. Further, the accuracy of the sensor measurements was improved by calibrating the sensor with emissivity coefficient of the sewer concrete. Overall, this study will ameliorate the present sewer corrosion monitoring capabilities by providing new data to models predicting sewer corrosion.

Thiyagarajan, K, Kodagoda, S, Van Nguyen, L & Ranasinghe, R 2018, 'Sensor Failure Detection and Faulty Data Accommodation Approach for Instrumented Wastewater Infrastructures', IEEE Access, vol. 6, no. 1, pp. 56562-56574.
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© 2013 IEEE. In wastewater industry, real-time sensing of surface temperature variations on concrete sewer pipes is paramount in assessing the rate of microbial-induced corrosion. However, the sensing systems are prone to failures due to the aggressively corrosive environmental conditions inside sewer assets. Therefore, reliable sensing in such infrastructures is vital for water utilities to enact efficient wastewater management. In this context, this paper presents a sensor failure detection and faulty data accommodation (SFDFDA) approach that aids to digitally monitor the health conditions of the sewer monitoring sensors. The SFDFDA approach embraces seasonal autoregressive integrated moving average model with a statistical hypothesis testing technique for enabling temporal forecasting of sensor variable. Then, it identifies and isolates anomalies in a continuous stream of sensor data whilst detecting early sensor failure. Finally, the SFDFDA approach provides reliable estimates of sensor data in the event of sensor failure or during the scheduled maintenance period of sewer monitoring systems. The SFDFDA approach was evaluated by using the surface temperature data sourced from the instrumented wastewater infrastructure and the results have demonstrated the effectiveness of the SFDFDA approach and its applicability to surface temperature monitoring sensor suites.

To, AWK, Paul, G & Liu, D 2018, 'A comprehensive approach to real-time fault diagnosis during automatic grit-blasting operation by autonomous industrial robots', Robotics and Computer-Integrated Manufacturing, vol. 49, pp. 13-23.
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© 2017 Elsevier Ltd This paper presents a comprehensive approach to diagnose for faults that may occur during a robotic grit-blasting operation. The approach proposes the use of information collected from multiple sensors (RGB-D camera, audio and pressure transducers) to detect for 1) the real-time position of the grit-blasting spot and 2) the real-time state within the blasting line (i.e. compressed air only). The outcome of this approach will enable a grit-blasting robot to autonomous diagnose for faults and take corrective actions during the blasting operation. Experiments are conducted in a laboratory and in a grit-blasting chamber during real grit-blasting to demonstrate the proposed approach. Accuracy of 95% and above has been achieved in the experiments.

Ulapane, N, Alempijevic, A, Valls Miro, J & Vidal-Calleja, T 2018, 'Non-destructive evaluation of ferromagnetic material thickness using Pulsed Eddy Current sensor detector coil voltage decay rate', NDT & E International, vol. 100, pp. 108-114.
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© 2018 Elsevier Ltd A ferromagnetic material thickness quantification method based on the decay rate of the Pulsed Eddy Current sensor detector coil voltage is proposed. An expression for the decay rate is derived and the relationship between the decay rate and material thickness is established. Pipe wall thickness estimation is done with a developed circular sensor incorporating the proposed method, and results are evaluated through destructive testing. The decay rate feature has a unique attribute of being lowly dependent on properties such as sensor shape and size, and lift-off, enabling the method to be usable with any detector coil-based sensor. A case study on using the proposed method with a commercial sensor is also presented to demonstrate its versatility.

Valls Miro, J, Ulapane, N, Shi, L, Hunt, D & Behrens, M 2018, 'Robotic pipeline wall thickness evaluation for dense nondestructive testing inspection', Journal of Field Robotics, vol. 35, no. 8, pp. 1293-1310.
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AbstractThis paper addresses automated mapping of the remaining wall thickness of metallic pipelines in the field by means of an inspection robot equipped with nondestructive testing (NDT) sensing. Set in the context of condition assessment of critical infrastructure, the integrity of arbitrary sections in the conduit is derived with a bespoke robot kinematic configuration that allows dense pipe wall thickness discrimination in circumferential and longitudinal direction via NDT sensing with guaranteed sensing lift‐off (offset of the sensor from pipe wall) to the pipe wall, an essential barrier to overcome in cement‐lined water pipelines. A tailored covariance function for pipeline cylindrical structures within the context of a Gaussian Processes has also been developed to regress missing sensor data incurred by a sampling strategy folllowed in the field to speed up the inspection times, given the slow response of the pulsed eddy current electromagnetic sensor proposed. The data gathered represent not only a visual understanding of the condition of the pipe for asset managers, but also constitute a quantative input to a remaining‐life calculation that defines the likelihood of the pipeline for future renewal or repair. Results are presented from deployment of the robotic device on a series of pipeline inspections which demonstrate the feasibility of the device and sensing configuration to provide meaningful 2.5D geometric maps.

Varisco, M, Deuse, J, Johnsson, C, Nöhring, F, Schiraldi, MM & Wöstmann, R 2018, 'From production planning flows to manufacturing operation management KPIs: linking ISO18828 & ISO22400 standards', IFAC-PapersOnLine, vol. 51, no. 11, pp. 25-30.
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© 2018 International standards are playing a key role in leading and shaping the smart manufacturing landscape. The integration and consistency among different standards is therefore essential to effectively support industrial automation evolution and to ensure their applicability. This paper focuses on the ISO18828 and ISO22400 standards, related to the production planning process and manufacturing, consequential phases in product lifecycle. In this paper the connections between the information related to production planning process (ISO18828) and the KPI main basic elements in manufacturing operation management (ISO22400) are analysed. The analysis aims at supporting the standards’ users, underlining the aspects that should be taken into account in order to consolidate and improve the considered lifecycle phases.

Wang, H, Huang, S, Yang, G & Dissanayake, G 2018, 'Comparison of two different objective functions in 2D point feature SLAM', Automatica, vol. 97, pp. 172-181.
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© 2018 Elsevier Ltd This paper compares two different objective functions in 2D point feature Simultaneous Localization and Mapping (SLAM). It is shown that the objective function can have a significant impact on the convergence of the iterative optimization techniques used in SLAM. When Frobenius norm is adopted for the error term of the orientation part of odometry, the SLAM problem has much better convergence properties, as compared with that using the angle difference as the error term. For one-step case, we have proved that there is one and only one minimum to the SLAM problem, and strong duality always holds. For two-step case, strong duality always holds except when three very special conditions hold simultaneously (which happens with probability zero), thus the global optimal solution to primal SLAM problem can be obtained by solving the corresponding Lagrangian dual problem in most cases. Further, for arbitrary m-step cases, we also show using examples that much better convergence results can be obtained. Simulation examples are given to demonstrate the different convergence properties using two different objective functions.

Wang, S, Kodagoda, S, Shi, L & Dai, X 2018, 'Two-Stage Road Terrain Identification Approach for Land Vehicles Using Feature-Based and Markov Random Field Algorithm', IEEE Intelligent Systems, vol. 33, no. 1, pp. 29-39.
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© 2001-2011 IEEE. Road terrain identification is one of the important tasks for driving assistant systems or autonomous land vehicles. It plays a key role in improving driving strategy and enhancing fuel efficiency. In this paper, a two-stage approach using multiple sensors is presented. In the first stage, a feature-based identification approach is performed using an accelerometer, a camera, and downward-looking and forward-looking laser range finders (LRFs). This produces four classification label sequences. In the second stage, a majority vote is implemented for each label sequences to match them into synchronized road patches. Then a Markov Random Field (MRF) model is designed to generate the final optimized identification results to improve the forward-looking LRF. This approach enables the vehicle to observe the upcoming road terrain before moving onto it by fusing all the classification results using an MRF algorithm. The experiments show this approach improved the terrain identification accuracy and robustness significantly for some familiar road terrains.

Wijaya, FB, Sepehrirahnama, S & Lim, K-M 2018, 'Interparticle force and torque on rigid spheroidal particles in acoustophoresis', Wave Motion, vol. 81, pp. 28-45.
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Williams, P, Kirby, R, Hill, J, Åbom, M & Malecki, C 2018, 'Reducing low frequency tonal noise in large ducts using a hybrid reactive-dissipative silencer', Applied Acoustics, vol. 131, pp. 61-69.
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© 2017 Elsevier Ltd Noise generated by fans or turbines normally consists of a combination of narrow and broadband noise. To lower transmitted noise levels, it is attractive to use a combination of reactive and dissipative elements. However, this approach presents a number of challenges for larger systems. This is because reactive elements are commonly placed around the duct circumference where they are normally only effective up to the frequency at which the first higher order mode cuts on in the duct. For larger systems, this means that reactive elements work only in the low, and often very low, frequency range, whereas dissipative elements, which are distributed across the duct cross-section, generally work well in the medium to high frequency range. This can cause noise problems in the low to medium frequency range in larger systems. This article presents an alternative approach for delivering noise attenuation over the low to medium frequency range that is suitable for application in larger duct systems. This approach takes advantage of those splitter silencer designs commonly used in larger systems to integrate a reactive element into the splitter design. This delivers a hybrid splitter that uses a combination of dissipative and reactive elements so that the reactive element partitions the main airway. This has the advantage of introducing a quasi-planar transverse sound pressure field for each resonator in the low to medium frequency range, including frequencies above the first cut-on. It is demonstrated using predictions and measurements taken for a number of example silencers, that this approach enables reactive elements to work over an extended low to medium frequency range, including at frequencies above the first cut-on mode in the main duct. Accordingly, it is shown that a hybrid dissipative-reactive splitter design is capable of delivering improved levels of attenuation in the crucial low to medium frequency range.

Yan, Y, Sencadas, V, Jin, T, Huang, X, Lie, W, Wei, D & Jiang, Z 2018, 'Effect of multi-walled carbon nanotubes on the cross-linking density of the poly(glycerol sebacate) elastomeric nanocomposites', Journal of Colloid and Interface Science, vol. 521, pp. 24-32.
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© 2018 Elsevier Inc. Processing conditions deeply affect the mechanical, chemical and biological properties of elastomeric based nanocomposites. In this work, multi-walled carbon nanotubes (MWCNTs) were dispersed in poly(glycerol sebacate) (PGS) prepolymer, followed by curing under vacuum at 120 °C. It was observed an increase of the water contact angle with the amount of MWCNTs added, as well as the tensile strength and Young modulus, without compromising the elastomeric behaviour of the pristine PGS matrix. The cross-linking degree was determined by the Flory-Rehner swelling method and through the mechanical rubber elasticity model, and an increase of more than six-fold was observed, which demonstrates the chemical conjugation between the MWCNTs and the PGS polymer chains, resulting in stiff and elastomeric nanocomposites. Finally, in vitro cell culture of adult mouse hypothalamus neurons A59 cells showed good support for cell viability and stimulation for axons and dendrites growth. The unique features of these nanocomposites make them promise for biomedical applications, as soft tissue substrates with tailored mechanical properties.

Ye, K & Ji, J 2018, 'Natural Frequency Analysis of a Spar-Type Offshore Wind Turbine Tower With End Mass Components', Journal of Offshore Mechanics and Arctic Engineering, vol. 140, no. 6, pp. 1-5.
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Abstract Different from the fixed-based wind turbines, the floating type wind turbines are regarded as under a free–free end operating condition. The tower structure of a floating offshore wind turbine is an integrated part connecting the nacelle and support platform. An analytic solution is presented in this technical brief for the free-vibration of the tower structure of a spar-type offshore wind turbine. The tower structure is modeled as a free–free beam based on Euler–Bernoulli beam-column theory. The platform and the nacelle are considered as two large mass components connected by torsion springs at two tower ends with different stiffness. The effects of system parameters on the natural frequencies are investigated under a range of variables, including the tower structure parameters, platform and nacelle parameters, and the connection types. Nonlinear relationships between those variables and the natural frequency of the tower structure are numerically found and some design issues are discussed for the spar-type floating wind turbines.

Ye, K & Ji, J 2018, 'The effect of the rotor adjustment on the vibration behaviour of the drive-train system for a 5 MW direct-drive wind turbine', Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, vol. 232, no. 17, pp. 3027-3044.
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Direct-drive wind turbines, different from the standard geared wind turbines, widely use a direct-drive permanent-magnet generator to avoid the gearbox failures. In the absence of a gearbox in the drive-train system, the direct-drive generator operates at low rotating speeds. Thus direct-drive wind turbines require a larger sized generator (higher weight) to transfer the kinetic energy into electrical energy. The inherent unbalanced magnetic pull force of the generator can have impact on the vibration behaviour of the drive-train system. This paper studies the effect of rotor position and weight adjustment on the vibration behaviour of the drive-train system within a 5 MW direct-drive wind turbine by considering the unbalanced magnetic pull force. The adjustment of rotor position and weight changes the location of the centre of gravity of the drive-train system. The drive-train system which consists of the main shaft, rotor, hub and blades is modelled as a four degree-of-freedom nonlinear system. Both rotor displacement and bearing forces are obtained for a wide range of rotor position and weight under different rotating speeds. The obtained results would provide useful information on the optimized rotor position and mass ratio to improve the performance of the drive-train system.

Yin, S, Yu, D, Luo, Z & Xia, B 2018, 'An arbitrary polynomial chaos expansion approach for response analysis of acoustic systems with epistemic uncertainty', Computer Methods in Applied Mechanics and Engineering, vol. 332, pp. 280-302.
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© 2017 Elsevier B.V. By introducing the arbitrary polynomial chaos theory, the Evidence-Theory-based Arbitrary Polynomial Chaos Expansion Method (ETAPCEM) is proposed to improve the computational accuracy of polynomial chaos expansion methods for the evidence-theory-based analysis of acoustic systems with epistemic uncertainty. In ETAPCEM, the epistemic uncertainty of acoustic systems is treated with evidence theory. The response of acoustic systems in the range of variation of evidence variables is approximated by the arbitrary polynomial chaos expansion, through which the lower and upper bounds of the response over all focal elements can be efficiently calculated by a number of numerical solvers. Inspired by the application of polynomial chaos theory in the interval and random analysis, the weight function of the optimal polynomial basis of ETAPCEM for evidence-theory-based uncertainty analysis is derived from the uniformity approach. Compared with the conventional evidence-theory-based polynomial chaos expansion methods, including the recently proposed evidence-theory-based Jacobi expansion method, the main advantage of ETAPCEM is that the polynomial basis orthogonalized with arbitrary weight functions can be obtained to construct the polynomial chaos expansion. Thereby the optimal polynomial basis of polynomial chaos expansion for arbitrary types of the evidence variable can be established by using ETAPCEM. The effectiveness of the proposed method for acoustic problems has been fully demonstrated by comparing it with the conventional evidence-theory-based polynomial chaos expansionmethods.

Yu, J, Ji, J, Miao, Z & Zhou, J 2018, 'Formation control with collision avoidance for uncertain networked Lagrangian systems via adaptive gain techniques', IET Control Theory & Applications, vol. 12, no. 10, pp. 1393-1401.
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© 2018 The Institution of Engineering and Technology. All rights reserved. This study addresses the problem of formation control with collision avoidance for networked Lagrangian systems with uncertain parameters interacting on directed network communication topologies. Two adaptive formation control strategies with collision avoidance are proposed by making use of adaptive gain techniques for both cases of with and without a dynamic leader. The main objective of the proposed control strategies is to dispatch a group of agents to maintain a desired geometric pattern, while still guarantee collision avoidance at any time, and eventually to achieve velocity matching. A distinctive feature of the developed adaptive gain is to adapt itself duly based on both the network communication topology and collision avoidance constraints, so it is feasible to be implemented in practice. Some general criteria are derived to guarantee that the desired formation with collision avoidance for the networked Lagrangian systems can be achieved. Finally, numerical simulations are given to show the performance of the proposed control methodologies.

Zhai, H, Xu, F, Saha, SC & Hou, Y 2018, 'Natural convection and heat transfer on a section-triangular roof', International Communications in Heat and Mass Transfer, vol. 92, pp. 23-30.
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Zhang, L & Ji, JC 2018, 'One-to-three resonant Hopf bifurcations of a maglev system', Nonlinear Dynamics, vol. 93, no. 3, pp. 1277-1286.
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© 2018, Springer Science+Business Media B.V., part of Springer Nature. This paper studies the dynamics of a maglev system around 1:3 resonant Hopf–Hopf bifurcations. When two pairs of purely imaginary roots exist for the corresponding characteristic equation, the maglev system has an interaction of Hopf–Hopf bifurcations at the intersection of two bifurcation curves in the feedback control parameter and time delay space. The method of multiple time scales is employed to drive the bifurcation equations for the maglev system by expressing complex amplitudes in a combined polar-Cartesian representation. The dynamics behavior in the vicinity of 1:3 resonant Hopf–Hopf bifurcations is studied in terms of the controller’s parameters (time delay and two feedback control gains). Finally, numerical simulations are presented to support the analytical results and demonstrate some interesting phenomena for the maglev system.

Zhao, L, Huang, S & Dissanayake, G 2018, 'Linear SFM: A hierarchical approach to solving structure-from-motion problems by decoupling the linear and nonlinear components', ISPRS Journal of Photogrammetry and Remote Sensing, vol. 141, pp. 275-289.
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© 2018 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) This paper presents a novel hierarchical approach to solving structure-from-motion (SFM) problems. The algorithm begins with small local reconstructions based on nonlinear bundle adjustment (BA). These are then joined in a hierarchical manner using a strategy that requires solving a linear least squares optimization problem followed by a nonlinear transform. The algorithm can handle ordered monocular and stereo image sequences. Two stereo images or three monocular images are adequate for building each initial reconstruction. The bulk of the computation involves solving a linear least squares problem and, therefore, the proposed algorithm avoids three major issues associated with most of the nonlinear optimization algorithms currently used for SFM: the need for a reasonably accurate initial estimate, the need for iterations, and the possibility of being trapped in a local minimum. Also, by summarizing all the original observations into the small local reconstructions with associated information matrices, the proposed Linear SFM manages to preserve all the information contained in the observations. The paper also demonstrates that the proposed problem formulation results in a sparse structure that leads to an efficient numerical implementation. The experimental results using publicly available datasets show that the proposed algorithm yields solutions that are very close to those obtained using a global BA starting with an accurate initial estimate. The C/C++ source code of the proposed algorithm is publicly available at https://github.com/LiangZhaoPKUImperial/LinearSFM.

Zhao, S, Cheng, E, Qiu, X, Burnett, I & Chia-chun Liu, J 2018, 'Spatial decorrelation of wind noise with porous microphone windscreens', The Journal of the Acoustical Society of America, vol. 143, no. 1, pp. 330-339.
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This paper explores the wind noise reduction mechanism of porous microphone windscreens by investigating the spatial correlation of wind noise. First, the spatial structure of the wind noise signal is studied by simulating the magnitude squared coherence of the pressure measured with two microphones at various separation distances, and it is found that the coherence of the two signals decreases with the separation distance and the wind noise is spatially correlated only within a certain distance less than the turbulence wavelength. Then, the wind noise reduction of the porous microphone windscreen is investigated, and the porous windscreen is found to be the most effective in attenuating wind noise in a certain frequency range, where the windscreen diameter is approximately 2 to 4 times the turbulence wavelengths (2 &lt; D0/ξ &lt; 4), regardless of the wind speed and windscreen diameter. The spatial coherence between the wind noise outside and inside a porous microphone windscreen is compared with that without the windscreen, and the coherence is found to decrease significantly when the windscreen diameter is approximately 2 to 4 times the turbulence wavelengths, corresponding to the most effective wind noise reduction frequency range of the windscreen. Experimental results with a fan are presented to support the simulations. It is concluded that the wind noise reduction mechanism of porous microphone windscreens is related to the spatial decorrelation effect on the wind noise signals provided by the porous material and structure.

Zhao, S, Dabin, M, Cheng, E, Qiu, X, Burnett, I & Liu, JC-C 2018, 'Mitigating wind noise with a spherical microphone array', The Journal of the Acoustical Society of America, vol. 144, no. 6, pp. 3211-3220.
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This paper utilizes a rigid spherical microphone array to reduce wind noise. In the experiments conducted, a loudspeaker is used to reproduce the desired sound signal and an axial fan is employed to generate wind noise in an anechoic chamber. The sound signal and wind noise are measured separately with the spherical microphone array and analyzed in the spherical harmonic domain. The wind noise is found to be irregularly distributed in the spherical harmonic domain, distinct from the sound signal which is concentrated in the first few spherical harmonic modes. This difference is utilized to reduce wind noise without degrading the desired sound pressure level (SPL) by use of a low pass filter method in the spherical harmonic domain. Experimental results with both single-tonal and multi-tonal sound signals demonstrate that the proposed method can reduce wind noise by more than 10 dB in the frequency range below 500 Hz. The SPL of the desired sound signal can be extracted from wind noise with an error within 1.0 dB, even when the sound level is 8 dB lower than wind noise.

Zheng, J, Luo, Z, Li, H & Jiang, C 2018, 'Robust topology optimization for cellular composites with hybrid uncertainties', International Journal for Numerical Methods in Engineering, vol. 115, no. 6, pp. 695-713.
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SummaryThis paper will develop a new robust topology optimization method for the concurrent design of cellular composites with an array of identical microstructures subject to random‐interval hybrid uncertainties. A concurrent topology optimization framework is formulated to optimize both the composite macrostructure and the material microstructure. The robust objective function is defined based on the interval mean and interval variance of the corresponding objective function. A new uncertain propagation approach, termed as a hybrid univariate dimension reduction method, is proposed to estimate the interval mean and variance. The sensitivity information of the robust objective function can be obtained after the uncertainty analysis. Several numerical examples are used to validate the effectiveness of the proposed robust topology optimization method.

Zheng, Y, Gao, L, Xiao, M, Li, H & Luo, Z 2018, 'Robust topology optimization considering load uncertainty based on a semi-analytical method', The International Journal of Advanced Manufacturing Technology, vol. 94, no. 9-12, pp. 3537-3551.
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© 2017, Springer-Verlag London Ltd. Uncertainty is omnipresent in engineering design and manufacturing. This paper dedicates to present a robust topology optimization (RTO) methodology for structural compliance minimization problems considering load uncertainty, which includes magnitude and direction uncertainty subjected to Gaussian distribution. To this end, comprehensible semi-analytical formulations are derived to fleetly calculate the statistical data of structural compliance, which is critical to the probability-based RTO problem. In order to avoid the influence of numerical units on evaluating the robust results, this paper considers a generic coefficient of variation (GCV) as robust index which contains both the expected compliance and standard variance. In addition, the accuracy and efficiency of semi-analytical formulas are validated by the Monte Carlo (MC) simulation; comparison results provide higher calculation efficiency over the MC-based optimization algorithms. Four numerical examples are provided via density-based approach to demonstrate the effectiveness and robustness of the proposed method.

Zwinkau, R, Möhle, R, Frentrup, S & Deuse, J 2018, 'Metall/Nichtmetall-Klassifikation von Partikeln mit Deep Learning', JOT Journal für Oberflächentechnik, vol. 58, no. 10, pp. 50-57.
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Abdo, P & Huynh, BP 1970, 'Effect of Passive Green Wall Modules on Air Temperature and Humidity', Volume 7: Fluids Engineering, ASME 2018 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Pittsburgh, Pennsylvania.
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Green walls are bio-filters developed to enhance air quality. Often, these walls form the base from which plants are grown; and the plant-wall system helps to remove both gaseous and particulate air pollutants. Green walls can be found indoors or outdoors and they are classified as passive or active systems. Their benefits include temperature reduction, improvement of air quality and reduction of air pollution, oxygen production as well as the social and psychological wellbeing. They can produce changes in the ambient conditions (temperature and humidity) of the air layers around them which create an interesting insulation effect. The effect of passive green wall modules on the air temperature and on humidity is investigated in this work. A closed chamber made of acrylic sheets is used to monitor the temperature and humidity variation caused by a green wall module placed at its center. Temperature and humidity are measured at different locations inside the chamber during operation for different modules with different plant species.

Abdo, P, Huynh, BP & Avakian, V 1970, 'Effect of Fan Speed on Air Flow Through a Green Wall Module', Volume 2: Development and Applications in Computational Fluid Dynamics; Industrial and Environmental Applications of Fluid Mechanics; Fluid Measurement and Instrumentation; Cavitation and Phase Change, ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting, American Society of Mechanical Engineers, Montreal, Quebec, Canad.
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Green or living walls are active bio-filters developed to enhance air quality. Often, these walls form the base from which plants are grown; and the plant-wall system helps to remove both gaseous and particulate air pollutants. They can be classified as passive or active systems. The active systems are designed with ventilators which force air through the substrate and plant rooting system, therefore the air is purified and filtered through a bio-filtration process which also acts as a natural cooling system. A fan positioned at a central opening on the module’s back face drives air through the medium-plant-roots mix and then onward through the plants’ canopy; and these would help to remove both gaseous and particulate pollutants from the air. Pressure drop across the module, air flow distribution through it as well as the total flow rate have been obtained. The effect of different fan speeds on the total air flow and on its distribution through the module is investigated in this study in order to optimize the energy consumption of the fans whilst maintaining the modules biofiltration efficiency.

Abdo, P, Huynh, BP & Avakian, V 1970, 'Effect of Green Wall Modules on Air Temperature and Humidity', Volume 2: Development and Applications in Computational Fluid Dynamics; Industrial and Environmental Applications of Fluid Mechanics; Fluid Measurement and Instrumentation; Cavitation and Phase Change, ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting, American Society of Mechanical Engineers, Montreal, Quebec, Canada.
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Green or living walls are active bio-filters developed to enhance air quality. Often, these walls form the base from which plants are grown; and the plant-wall system helps to remove both gaseous and particulate air pollutants. They can be classified as passive or active systems. The active systems are designed with ventilators which force air through the substrate and plant rooting system, therefore the air is purified and filtered through a bio-filtration process which also acts as a natural cooling system. Their benefits include temperature reduction, improvement of air quality and reduction of air pollution, oxygen production as well as the social and psychological wellbeing. They can produce changes in the ambient conditions (temperature and humidity) of the air layers around them which create an interesting insulation effect. The effect of green wall modules on the air temperature and on humidity is investigated in this work. A closed chamber made of acrylic sheets is used to monitor the temperature and humidity variation caused by a green wall module placed at its center. A fan positioned at the back center of the module drives air at ambient conditions and direct it into the module. Temperature and humidity are measured at different locations inside the chamber during operation for different modules with different plant species. The effect of changing the surrounding ambient conditions is also investigated.

Abdo, P, Taghipour, R & Huynh, BP 1970, 'Effect of Windcatcher’s Inlet Shape on Ventilation Flow Through a Two Dimensional Room', Volume 2: Development and Applications in Computational Fluid Dynamics; Industrial and Environmental Applications of Fluid Mechanics; Fluid Measurement and Instrumentation; Cavitation and Phase Change, ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting, American Society of Mechanical Engineers, Canada.
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Natural ventilation is the process of supplying and removing air through an indoor space by natural means. Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment by decreasing moisture content in the air and reducing pollutants concentration. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns aimed at helping wind to channel down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of the inlet design is investigated to achieve better air flow and increase the efficiency of windcatchers. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a two dimensional room fitted with a windcatcher based on different inlet designs such as a uniform inlet, a divergent inlet and a bulging-convergent inlet.

Abdo, P, Taghipour, R & Huynh, BP 1970, 'EFFECT OF WINDCATCHER’S INLET SHAPE ON VENTILATION FLOW THROUGH A TWO DIMENSIONAL ROOM', Proceedings of the ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting (FEDSM2018), The ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting (FEDSM2018), The American Society of Mechanical Engineers (ASME), Montreal, Quebec, Canada.

Abdo, P, Taghipour, R & Huynh, BP 1970, 'Simulation of buoyancy driven and winddriven ventilation flow in a three dimensional room fitted with a windcatcher', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018, Australasian Fluid Mechanics Conference, The Australasian Fluid Mechanics Society, Adelaide, Australia.
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© 2018 Australasian Fluid Mechanics Society. All rights reserved. Natural ventilation is the process of supplying and removing air through an indoor space by natural means. There are two types of natural ventilation occurring in buildings: winddriven ventilation and buoyancy driven or stack ventilation. Combining the wind driven and the buoyancy driven ventilation will be investigated in this study through the use of a windcatcher natural ventilation system. As stack driven air rises leaving the windcatcher, it is replaced with fresh air from outside entering through the positively pressured windward side. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a three dimensional room fitted with a windcatcher based on the winddriven ventilation alone, and combined buoyancy and winddriven ventilation. A three dimensional real sized room with a length of 5 m, a width of 4 m and a height of 3 m fitted with a windcatcher is modeled in this study using Ansys Fluent. The combined, buoyancy driven and winddriven ventilation, has provided approximately 3.16% increase in the total air flow rate, when heat flux of 500 W/m2 is applied at the front and bottom walls of the windcatcher’s outlet compared to the winddriven ventilation only. The pattern of air flow through the room has provided full ventilation at 1.2 m height where most of the human occupancy occurs.

Alvarez, JK & Kodagoda, S 1970, 'Application of deep learning image-to-image transformation networks to GPR radargrams for sub-surface imaging in infrastructure monitoring', 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Wuhan, China, pp. 611-616.
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The corrosion of reinforced concrete sewer pipes in aging infrastructure is a serious ongoing issue and as such, research into technologies that allow for autonomous site assessments are of major priority to wastewater managing utilities. The use of Ground Penetrating Radar (GPR) is being investigated for providing sub-surface images of sewer crowns. Due to the nature of GPRs, the analysis of a radargram for identifying sub-surface features is non-intuitive and usually require the use of an expert. Traditional methods to help ease analysis involve the use of Synthetic Aperture Radar (SAR) and migration techniques. These techniques refocus dipping and point reflectors to be closer to their true shape but require an accurate velocity model to be effective. This is not always readily available and difficult to estimate especially in regards to sewer conditions. We instead provide an alternative and present a deep learning framework for transforming ground penetrating radargrams into sub-surface permittivity maps. An evaluation of various state-of-the-art deep learning architectures is also conducted, comparing the performance of different objective functions and identifying current limitations. This work provides the base for further exploration of the application of deep learning for use in infrastructure monitoring.

Best, G, Forrai, M, Mettu, RR & Fitch, R 1970, 'Planning-Aware Communication for Decentralised Multi-Robot Coordination', 2018 IEEE International Conference on Robotics and Automation (ICRA), 2018 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Brisbane, QLD, Australia, pp. 1050-1057.
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© 2018 IEEE. We present an algorithm for selecting when to communicate during online planning phases of coordinated multi-robot missions. The key idea is that a robot decides to request communication from another robot by reasoning over the predicted information value of communication messages over a sliding time-horizon, where communication messages are probability distributions over action sequences. We formulate this problem in the context of the recently proposed decentralised Monte Carlo tree search (Dec-MCTS) algorithm for online, decentralised multi-robot coordination. We propose a particle filter for predicting the information value, and a polynomial-time belief-space planning algorithm for finding the optimal communication schedules in an online and decentralised manner. We evaluate the benefit of informative communication planning for a multi-robot information gathering scenario with 8 simulated robots. Our results show reductions in channel utilisation of up to four-fifths with surprisingly little impact on coordination performance.

Best, G, Huang, S & Fitch, R 1970, 'Decentralised Mission Monitoring with Spatiotemporal Optimal Stopping', 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Madrid, Spain, pp. 4810-4817.
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© 2018 IEEE. We consider a multi-robot variant of the mission monitoring problem. This problem arises in tasks where a robot observes the progress of another robot that is stochastically following a known trajectory, among other applications. We formulate and solve a variant where multiple tracker robots must monitor a single target robot, which is important because it enables the use of multi-robot systems to improve task performance in practice, such as in marine robotics missions. Our algorithm coordinates the behaviour of the trackers by computing optimal single-robot paths given a probabilistic representation of the other robots' paths. We employ a decentralised scheme that optimises over probability distributions of plans and has useful analytical properties. The planned trajectories collectively maximise the probability of observing the target throughout the mission with respect to probabilistic motion and observation models. We report simulation results for up to 8 robots that support our analysis and indicate that our algorithm is a feasible solution for improving the performance of mission monitoring systems.

Bhowmick, S, Xu, F & Saha, SC 1970, 'NATURAL CONVECTION IN A V-SHAPED CAVITY', International Heat Transfer Conference 16, International Heat Transfer Conference 16, Begellhouse, pp. 2977-2985.
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© 2018 International Heat Transfer Conference. All rights reserved. Natural convection is widely present in industrial system and in nature such as in a valley due to sun radiation and thus the study of natural convection in a v-shaped cavity is of significance. In this study, the transition of natural convection in a v-shaped cavity to a chaotic state is numerically investigated. A wide range of Rayleigh numbers from 100 to 108 for the Prandtl number of 0.71 and the aspect ratio of 0.5 are considered. A set of bifurcations are described including the Pitchfork bifurcation from symmetrical to asymmetrical state and the Hopf bifurcation from steady to unsteady state. The critical Rayleigh numbers of bifurcations are obtained based on a great number of numerical tests. The spectral analysis is applied for unsteady natural convection in the cavity and the fundamental frequency is obtained. Further, the dependence on the Rayleigh number of the Nusselt number through the v-shaped cavity is quantified and the scaling relation between the Nusselt number and the Rayleigh number is presented.

Bykerk, L & Liu, D 1970, 'Experimental Verification of a Completely Soft Gripper for Grasping and Classifying Beam Members in Truss Structures', 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), IEEE, Auckland, New Zealand, pp. 756-761.
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© 2018 IEEE. Robotic object exploration and identification methods to date have attempted to mimic human Exploratory Procedures (EPs) using complex, rigid robotic hands with multifaceted sensory suites. For applications where the target objects may have different or unknown cross-sectional shapes and sizes (e.g. beam members in truss structures), rigid grippers are not a good option as they are unable to adapt to the target objects. This may make it very difficult to recognise the shape and size of a beam member and the approaching angles which would result in a secure grasp. To best meet the requirements of adaptability and compliancy, a soft robotic gripper with simple exteroceptive force sensors has been designed. This paper experimentally verifies the gripper design by assessing its performance in grasping and adapting to a variety of target beam members in a truss structure. The sensor arrangement is also assessed by verifying that sufficient data is extracted during a grasp to recognise the approaching angle of the gripper. Firstly, the gripper is used to grasp each beam member from various angles of approach and readings from the force sensors are collected. Secondly, the collected sensor data is used to train and then test a range of commonly used classifiers for classification of the angle of approach. Thirdly, the classification results are analysed. Through this process, it is found that the gripper is proficient in grasping the variety of target beam members. Despite the uncertainty in the gripper pose, the sensor data collected from the soft gripper during a grasp is sufficient for classification of the angles of approach.

Cetindamar, D, Lammers, T & Sick, N 1970, 'Establishing Entrepreneurship Ecosystems Based on Digital Technologies: A Policy Roadmap Approach at the City Level', 2018 Portland International Conference on Management of Engineering and Technology (PICMET), 2018 Portland International Conference on Management of Engineering and Technology (PICMET), IEEE, Honolulu, pp. 1-5.
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The last decade has witnessed the rise of technology-based entrepreneurs who managed to build companies based on the use of emerging digital technologies. However, the pure availability of digital technologies in a particular country does not guarantee to establish successful companies and economic growth. Companies are located in certain regional or urban environments with varying contextual factors. Cities have been a popular unit of analysis for technological development and economic activities due to their high dependency on immediate local environmental factors. Nevertheless, the literature offers a limited view on the relationship between technological developments and entrepreneurial activities at city level 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 offers a conceptual approach that might help policy makers to plan the future competitiveness of their cities.

Chen, Y, Huang, S, Fitch, R & Yu, J 1970, 'Efficient Active SLAM Based on Submap Joining, Graph Topology and Convex Optimization', 2018 IEEE International Conference on Robotics and Automation (ICRA), 2018 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Brisbane, QLD, Australia, pp. 5159-5166.
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© 2018 IEEE. The active SLAM problem considered in this paper aims to plan a robot trajectory for simultaneous localization and mapping (SLAM) as well as for an area coverage task with robot pose uncertainty. Based on a model predictive control (MPC) framework, these two problems are solved respectively by different methods. For the uncertainty minimization MPC problem, based on the graphical structure of the 2D feature-based SLAM, a non-convex constrained least-squares problem is presented to approximate the original problem. Then, using variable substitutions, it is further transformed into a convex problem, and then solved by a convex optimization method. For the coverage task considering robot pose uncertainty, it is formulated and solved by the MPC framework and the sequential quadratic programming (SQP) method. In the whole process, considering the computation complexity, we use linear SLAM, which is a submap joining approach, to reduce the time for planning and estimation. Finally, various simulations are presented to validate the effectiveness of the proposed approach.

Croaker, PJ, Karimi, M & Kessissoglou, N 1970, 'A computationally efficient approach to predict the acoustic fields from a cylinder in cross flow', INTER-NOISE and NOISE-CON Congress and Conference Proceedings, NOVEM 2018 - Noise and Vibration Emerging Methods - 6th conference, Institute of Noise Control Engineering, Ibiza, Spain, pp. 907-918.

Dai, B, Le Gentil, C & Vidal-Calleja, T 1970, 'Connecting the dots for real-time LiDAR-based object detection with YOLO', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, Lincoln, New Zealand.
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In this paper we introduce a generic method for people and vehicle detection using LiDAR data only, leveraging a pre-trained Convolutional Neural Network (CNN) from the RGB domain. Typically with machine learning algorithms, there is an inherent trade-off between the amount of training data available and the need for engineered features. The current state-of-the-art object detection and classification heavily rely on deep CNNs trained on enormous RGB image datasets. To take advantage of this inbuilt knowledge, we propose to fine-tune You only look once (YOLO) network transferring its understanding about object shapes to upsampled LiDAR images. Our method creates a dense depth/intensity map, which highlights object contours, from the 3D-point cloud of a LiDAR scan. The proposed method is hardware agnostic, hence can be used with any LiDAR data, independently on the number of channels or beams. Overall, the proposed pipeline exploits the notable similarity between upsampled LiDAR images and RGB images preventing the need to train a deep CNN from scratch. This transfer learning makes our method data efficient while avoiding the creation of heavily engineered features. Evaluation results show that our proposed LiDAR-only detection model has equivalent performance to its RGB-only counterpart.

Fahmideh, M & Lammers, T 1970, 'A study of influential factors in designing self-reconfigurable robots for green manufacturing', ACIS 2018 - 29th Australasian Conference on Information Systems, Australasian Conference on Information Systems, ACIS, Sydney, pp. 1-7.
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© 2018 ACIS2018.org. All rights reserved. There is incremental growth in adopting self-reconfigurable robots in automating manufacturing conventional product lines. Using this class of robots adapting themselves with ever-changing environmental conditions has been acclaimed as a promising way of reducing energy consumption and environmental impact and thus enabling green manufacturing. Whilst the majority of existing research focuses on highlighting the efficacy of self-reconfigurable robots in energy reduction with technical driven solutions, the research on exploring the salient factors in design and development self-reconfigurable robots that directly enable or hinder green manufacturing is non-extant. This interdisciplinary research contributes to the nascent body of the knowledge by empirical investigation of design-time, run-time, and hardware aspects which should be contingently balanced when developing green-aware self-reconfigurable robots.

Fahmideh, M & Lammers, T 1970, 'A study of influential factors in designing self-reconfigurable robots for green manufacturing', ACIS 2018 - 29th Australasian Conference on Information Systems, University of Technology, Sydney.
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There is incremental growth in adopting self-reconfigurable robots in automating manufacturing conventional product lines. Using this class of robots adapting themselves with ever-changing environmental conditions has been acclaimed as a promising way of reducing energy consumption and environmental impact and thus enabling green manufacturing. Whilst the majority of existing research focuses on highlighting the efficacy of self-reconfigurable robots in energy reduction with technical driven solutions, the research on exploring the salient factors in design and development self-reconfigurable robots that directly enable or hinder green manufacturing is non-extant. This interdisciplinary research contributes to the nascent body of the knowledge by empirical investigation of design-time, run-time, and hardware aspects which should be contingently balanced when developing green-aware self-reconfigurable robots.

Falque, R, Patel, M & Biehl, J 1970, 'Optimizing Placement and Number of RF Beacons to Achieve Better Indoor Localization', 2018 IEEE International Conference on Robotics and Automation (ICRA), 2018 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Brisbane, QLD, Australia, pp. 2304-2311.
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© 2018 IEEE. In this paper, we propose a novel solution to optimize the deployment of Radio Frequency (RF) beacons for the purpose of indoor localization. We propose a system that optimizes both the number of beacons and their placement in a given environment. We propose a novel cost-function, called CovBsm, that allows to simultaneously optimize the 3-coverage while maximizing the beacon spreading. Using this cost function, we propose a framework that maximize both the number of beacons and their placement in a given environment. The proposed solution accounts for the indoor infrastructure and its influence on the RF signal propagation by embedding a realistic simulator into the optimization process.

Furukawa, T, Dissanayake, G, Attia, T & Hodges, J 1970, 'A Bayesian Framework for Simultaneous Robot Localization and Target Detection and Engagement', 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Madrid, Spain, pp. 7151-7157.
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© 2018 IEEE. This paper presents a framework for engaging a target while approaching it from a long distance, using observation from sensors on-board a mobile robot. The proposed framework consists of two multi-stage Bayesian approaches to reliably detect and accurately engage with the target under uncertainties. The multi-stage localization approach localizes the robot and the target in a global coordinate frame. Their locations are estimated sequentially when the robot is at a long distance from the target, whereas they are localized simultaneously when the target is in the close vicinity. In the multi-stage target observation approach, a level of confidence and the associated probability of detection of the sensor are defined to make the target detectable in maximal occasions. This allows the extended Kalman filter to be implemented for the target engagement. The proposed framework was implemented on an unmanned ground vehicle equipped with multiple sensors. Results show the effectiveness of the proposed framework in solving real-world problems.

Gong, S, Wang, X & Oberst, S 1970, 'Non-linear Analysis of Vibrating Flip-flow Screens', MATEC Web of Conferences, International Conference on Design and Manufacturing Engineering, EDP Sciences, Monash University, Melbourne, Australia, pp. 04007-04007.
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Vibrating flip-flow screens provide an effective solution for the screening of highly viscous or fine materials. Apart from other factors, the vibration characteristics of the main and floating screen frames are largely responsible for the flip-flow screen’s sifting performance and its processing capacity. In this paper, the vibration characteristics of a vibrating flip-flow screen with linear and nonlinear springs are compared. Analytical results highlight that increasing the relative amplitude and avoiding undesirable resonances of the main and the floating screen frames can be realised to improve the screen’s performance. The materials on the screen panel have less an effect on the vibration characteristics of the vibrating flip-flow screen with nonlinear springs than using linear springs. Other design parameters which influence the performance of vibrating flip-flow screens are discussed.

Guertler, MR 1970, 'HOW TO DESIGN METHODS FOR APPLICATION - EMPIRICAL INSIGHTS FROM INDUSTRY', Proceedings of the DESIGN 2018 15th International Design Conference, 15th International Design Conference, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Croatia; The Design Society, Glasgow, UK, Dubrovnik, pp. 1161-1172.
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Methods support designers in systematically developing new or improving products and processes. Despite their benefits, the use of methods in industry is still limited. Methods are often perceived as too abstract and not suitable by industry users. Research has tended to focus on the selection and application of methods. This paper proposes to extend the scope and include the design of methods themselves. Based on literature and empirical insights from research projects in industry, it derives a first set of requirements for designing new methods and increasing their usability and acceptance.

Guertler, MR, Kriz, A & Sick, N 1970, 'Action Innovation Management-Research: Beyond an R&R Trade-off in Innovation Management', The ISPIM Innovation Conference – Innovation, The Name of The Game, Stockholm, pp. 1-17.

Halkon, B & Rothberg, S 1970, 'Taking laser Doppler vibrometry off the tripod', 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, International Congress on Sound and Vibration, Curran, Hiroshima, Japan, pp. 136-143.
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Laser Doppler vibrometers are now well-established as an effective non-contact alternative to traditional contacting transducers. Despite over 30 years of successful applications, however, very little attention has been given to sensitivity to vibration of the instrument itself. In this paper, sensitivity to instrument vibration and steering optics vibration is confirmed before development theoretically and experimentally of practical schemes to enable correction of measurements. In the case of instrument vibration, the correction scheme requires a pair of sensors with appropriate orientation and relative location. In the case of a beam steering mirror vibration, the correction scheme requires a single measurement from an appropriate location on the back-surface of the mirror in line with the laser beam incidence point. In both cases, frequency domain processing conveniently accommodates inter-channel time delay and signal integrations. Error reductions in excess of 30 dB are delivered in laboratory tests with simultaneous instrument / steering optic and target vibration over a broad frequency range. The practical nature of the correction techniques is demonstrated by successful applications of each. Finally, a previously unreported challenging real-world measurement scenario is described.

Halkon, BJ & Rothberg, SJ 1970, 'Towards laser Doppler vibrometry from unmanned aerial vehicles', Journal of Physics: Conference Series, 13th International Conference on Vibration Measurements by Laser and Noncontact Techniques, IOP Publishing, Ancona, Italy, pp. 012022-012022.
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© 2019 Published under licence by IOP Publishing Ltd. Laser Doppler vibrometers are technically well suited to general application but they offer special benefits in a variety of challenging measurement scenarios which are now well documented and accepted. An interesting and potentially powerful example of such a challenging measurement scenario is one where the laser vibrometer is mounted on/in an unmanned aerial vehicle in order that autonomous measurement campaigns can be undertaken in remote and/or harsh environments. One important challenge to overcome in such a scenario is the measurement sensitivity to vibration of the instrument itself or indeed of any steering optics used to point the probe laser beam toward the target of interest. In this paper, recently reported means by which this measurement sensitivity can be rectified by simultaneously obtained correction measurements will be developed. Specifically, this development is intended to lead towards laser Doppler vibrometry from unmanned aerial vehicles (UAVs) with correction of instrument motion being presented herein for the first time from a single, rather than a pair of, uniaxial accelerometers.

Hassan, M & Liu, D 1970, 'A Deformable Spiral Based Algorithm to Smooth Coverage Path Planning for Marine Growth Removal', 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Madrid, Spain, pp. 1913-1918.
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© 2018 IEEE. Ahstract- Marine growths that flourish on the surfaces of underwater structures, such as bridge pylons, make the inspection and maintenance of these structures challenging. A robotic solution, using an Intervention Autonomous Underwater Vehicle (I-AUV), is developed for removing marine growth. This paper presents a Deformable Spiral Coverage Path Planning (DSCPP) algorithm for marine growth removal. DSCPP generates smooth paths to prevent damage to the surfaces of the structures and to avoid frequent or aggressive decelerations and accelerations due to sharp turns. DSCPP generates a spiral path within a circle and analytically maps the path to a minimum bounding rectangle which encompasses an area of a surface with marine growth. It aims to achieve a spiral path with minimal length while preventing missed areas of coverage. Several case studies are presented to validate the algorithm. Comparison results show that DSCPP outperforms the popular boustrophedon-based coverage approach when considering the requirements for the application under consideration.

Hassan, M & Liu, D 1970, 'Performance Evaluation of an Evolutionary Multiobjective Optimization Based Area Partitioning and Allocation Approach', 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), IEEE, Auckland, New Zealand, pp. 527-532.
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© 2018 IEEE. An Area Partitioning and Allocation (APA) approach was presented in[1]. The approach focused on optimizing the coverage performance of Autonomous Industrial Robots (AIRs) using multiple conflicting objectives and Voronoi partitioning. However, questions related to the optimality, convergence, and consistency of the Pareto solutions were not studied in details. In this paper, Inverted Generational Distance (IGD) metric is used to verify the convergence of the Pareto front towards Pareto optimal front (PF∗). The consistency in obtaining similar Pareto fronts for independent optimization runs is studied. The computational complexity of the approach with respect to the size of the coverage area and the number of AIRs is also discussed. Two application scenarios are used in this research.

Hayati, H, Walker, P, Brown, T, Kennedy, P & Eager, D 1970, 'A Simple Spring-Loaded Inverted Pendulum (SLIP) Model of a Bio-Inspired Quadrupedal Robot Over Compliant Terrains', Volume 4B: Dynamics, Vibration, and Control, ASME 2018 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, USA.
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To study the impact of compliant terrains on the biomechanics of rapid legged movements, a well-known spring loaded inverted pendulum (SLIP) model is deployed. The model is a three-degrees-of-freedom system (3 DOF), inspired by galloping greyhounds competing in a racing condition. A single support phase of hind-leg stance in a galloping gait is taken into consideration due to its primary function in powering the greyhounds locomotion and higher rate of musculoskeletal injuries. To obtain and solve the nonlinear second-order differential equation of motions, the Lagrangian method and MATLABb R2017b (ode45 solver), which is based on the Runge-Kutta method, has been used, respectively. To get the viscoelastic behavior of compliant terrains, a Clegg hammer test was developed and performed five times on each sample. The effective spring and damping coefficients of each sample were then determined from the hysteresis curves. The results showed that galloping on the synthetic rubber requires more muscle force compared with wet sand. However, according to the Clegg hammer test, wet sand had a higher impact force than synthetic rubber which can be a risk factor for bone fracture, particularly hock fracture, in greyhounds. The results reported in this paper are not only useful for identifying optimum terrain properties and injury thresholds of an athletic track, but also can be used to design control methods and shock impedances for legged robots performing on compliant terrains.

Hayati, H, Walker, P, Mahdavi, F, Stephenson, R, Brown, T & Eager, D 1970, 'A Comparative Study of Rapid Quadrupedal Sprinting and Turning Dynamics on Different Terrains and Conditions: Racing Greyhounds Galloping Dynamics', Volume 4A: Dynamics, Vibration, and Control, ASME 2018 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Pittsburgh, Pennsylvania, USA, pp. 1-7.
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Identifying optimum athletic race track surfacing for greyhounds to reduce risk of injuries is a challenging practice as there are several single and coupled variables that should be considered as risk factors. To study the impact of bend and straight sections, surface type and camber, on biomechanics of galloping quadrupeds, an inertial measurement unit (IMU). has been used to measure the associated galloping accelerations. The IMU was sewn into a pocket located on the back of the greyhounds racing jacket positioned between the two forelegs. Simultaneous kinematics were performed using high frame rate (HFR) videos for calibrating IMU data. The results showed that there were lower G-forces on galloping on grass than wet sand which is consistent with the mechanical behavior of grass (grass is softer than wet sand). Moreover, galloping around the bend had higher G-forces than galloping along the straight section suggesting an excessive force is applied on the greyhound’s limbs due to centrifugal force. A cambered bend assisted the greyhounds in having a smoother gait and lower G-forces when compared to a flat bend. The results reported in this paper will not only be beneficial for the welfare of racing greyhounds, but will also contribute in the simulation of legged locomotion for bio-inspired engineering and robotics.

Held, T & Lammers, T 1970, 'A trend study of ecological product development partnerships in the German foundry value chain', Purchasing and Supply Chain Management: Fostering Innovation, International Purchasing & Supply Education & Research Association, Athens, pp. 632-650.
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Cross-company cooperation and early supplier involvement in product development gained importance in the last decades due to higher technological complexity and increased outsourcing activities. At the same time ecological aspects became more important. This paper analyzes economic and ecological aspects of product development partnerships in the German foundry industry. The analysis is based on comprehensive surveys conducted in 2013 and 2017 covering supplier and customer integration issues and potentials at the interfaces of German casting houses and their customers. In general, little significant change could be discovered: the arrangement of cross-company product development of castings seems rather stable.

Huizingh, E, Sick, N, Guertler, M & Kriz, A 1970, 'Towards A Method To Tackle Wicked Problems In Innovation Management', R&D Management Conference, Milan, Italy.

Hunt, D, Hussein, M, Stewart, C, Dissanayake, G, Miro, JV, Olson, J & Rossi, R 1970, 'Rapid response non-destructive inspection robot for condition assessment of critical water mains', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Lincoln University, New Zealand, pp. 1-7.
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This paper presents a robotic system that is able to rapidly assess the wall thickness of a cement lined cast iron (CI) water main pipe during the short time interval between a pipe failure and its repair. Wall thickness measurement through a cement lining of unknown depth is achieved using a sensor based on the pulsed eddy current (PEC) technique. Sensor geometry is selected such that remaining wall thickness' up to 20mm can be reliably measured. A six arm mechanism incorporating inbuilt compliance allows contact between the sensors and cement lining to be maintained even when the cement lining thickness is non-uniform; which is typically the case with in-situ lined pipes. A cart capable of navigating debris and steps transports the sensing mechanism through the pipe and also ensures it is positioned concentrically within a range of pipe sizes. Descriptions of the sensing strategy, sensor mechanism, driving cart and the robot control system are presented together with results from actual in-field pipe deployments to demonstrate effectiveness of the developed system.

Islam, MS, Saha, SC & Young, PM 1970, 'Aerosol particle transport and deposition in a CT-based lung airway for helium-oxygen mixture', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018.
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A precise understanding of the aerosol particle transport and deposition (TD) in the human lung is important to improve the efficiency of the targeted drug delivery, as the current drug delivery device can deliver only a small amount of the drug to the terminal airways. A wide range of available computational and experimental model has improved the understanding of particle TD in the human lung for air breathing. However, the helium-oxygen gas mixture breathing is less dense than the air breathing and the turbulent dispersion is less likely to develop at the upper airways, which eventually reduce the higher deposition at the upper airways. This study aims to investigate the effects of the helium-oxygen gas mixture at the upper airways of a realistic human lung. A realistic lung model is developed from the CT-Scan data for a healthy adult. A Low Reynolds Number (LRN) k-ω model is used to calculate the fluid motion and Lagrangian particle tracking scheme is used for particle transport. ANSYS Fluent solver (19.0) is used for the numerical simulation and MATLAB software is used for the advanced post-processing. The numerical results show that helium-oxygen gas mixture breathing reduces the aerosol deposition at the upper airways than the air breathing. The present simulation along with more case-specific investigation will improve the understanding of the particle TD for the helium-oxygen mixture.

Islam, MS, Saha, SC & Young, PM 1970, 'Aerosol particle transport and deposition in a CT-based lung airway for helium-oxygen mixture', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018.
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© 2018 Australasian Fluid Mechanics Society. All rights reserved. A precise understanding of the aerosol particle transport and deposition (TD) in the human lung is important to improve the efficiency of the targeted drug delivery, as the current drug delivery device can deliver only a small amount of the drug to the terminal airways. A wide range of available computational and experimental model has improved the understanding of particle TD in the human lung for air breathing. However, the helium-oxygen gas mixture breathing is less dense than the air breathing and the turbulent dispersion is less likely to develop at the upper airways, which eventually reduce the higher deposition at the upper airways. This study aims to investigate the effects of the helium-oxygen gas mixture at the upper airways of a realistic human lung. A realistic lung model is developed from the CT-Scan data for a healthy adult. A Low Reynolds Number (LRN) k-ω model is used to calculate the fluid motion and Lagrangian particle tracking scheme is used for particle transport. ANSYS Fluent solver (19.0) is used for the numerical simulation and MATLAB software is used for the advanced post-processing. The numerical results show that helium-oxygen gas mixture breathing reduces the aerosol deposition at the upper airways than the air breathing. The present simulation along with more case-specific investigation will improve the understanding of the particle TD for the helium-oxygen mixture.

Islam, MS, Saha, SC & Young, PM 1970, 'Aerosol particle transport and deposition in a CT-based lung airway for helium-oxygen mixture', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018.
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© 2018 Australasian Fluid Mechanics Society. All rights reserved. A precise understanding of the aerosol particle transport and deposition (TD) in the human lung is important to improve the efficiency of the targeted drug delivery, as the current drug delivery device can deliver only a small amount of the drug to the terminal airways. A wide range of available computational and experimental model has improved the understanding of particle TD in the human lung for air breathing. However, the helium-oxygen gas mixture breathing is less dense than the air breathing and the turbulent dispersion is less likely to develop at the upper airways, which eventually reduce the higher deposition at the upper airways. This study aims to investigate the effects of the helium-oxygen gas mixture at the upper airways of a realistic human lung. A realistic lung model is developed from the CT-Scan data for a healthy adult. A Low Reynolds Number (LRN) k-ω model is used to calculate the fluid motion and Lagrangian particle tracking scheme is used for particle transport. ANSYS Fluent solver (19.0) is used for the numerical simulation and MATLAB software is used for the advanced post-processing. The numerical results show that helium-oxygen gas mixture breathing reduces the aerosol deposition at the upper airways than the air breathing. The present simulation along with more case-specific investigation will improve the understanding of the particle TD for the helium-oxygen mixture.

Jadidi, MG, Patel, M, Miro, JV, Dissanayake, G, Biehl, J & Girgensohn, A 1970, 'A Radio-Inertial Localization and Tracking System with BLE Beacons Prior Maps', 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN), IEEE, Nantes, France.
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© 2018 IEEE. In this paper, we develop a system for the low-cost indoor localization and tracking problem using radio signal strength indicator, Inertial Measurement Unit (IMU), and magnetometer sensors. We develop a novel and simplified probabilistic IMU motion model as the proposal distribution of the sequential Monte-Carlo technique to track the robot trajectory. Our algorithm can globally localize and track a robot with a priori unknown location, given an informative prior map of the Bluetooth Low Energy (BLE) beacons. Also, we formulate the problem as an optimization problem that serves as the Backend of the algorithm mentioned above (Front-end). Thus, by simultaneously solving for the robot trajectory and the map of BLE beacons, we recover a continuous and smooth trajectory of the robot, corrected locations of the BLE beacons, and the time-varying IMU bias. The evaluations achieved using hardware show that through the proposed closed-loop system the localization performance can be improved; furthermore, the system becomes robust to the error in the map of beacons by feeding back the optimized map to the Front-end.

Jingyang, Z, Jinchen, J, Shan, Y & Van Canh, T 1970, 'The Load Distribution of the Main Shaft Bearing Considering Combined Load and Misalignment in a Floating Direct-Drive Wind Turbine', E3S Web of Conferences, International Conference on Power and Renewable Energy, EDP Sciences, Berlin, Germany, pp. 07009-07009.
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The main shaft tapered double-inner ring bearing (TDIRB) of floating direct-drive wind turbine system (FDDWT) is one of the most critical components in FDDWT, and its failure accounts for a large proportion of wind turbine malfunctions and faults. Over the past decades, a significant number of methods have been proposed to calculate the contact load distribution along the roller length in TDIRB, since the contact load distribution of roller is the key factor of fatigue life of TDIRB. Most of methods, however, neglected the misalignment of inner ring with respect to outer ring and friction force. In this paper, with the help of comprehensive and accurate quasi-static mathematical method, the contact load distribution of internal loads in TDIRB are analysed by considering the effects of combined loads, angular misalignment and friction force at different wind speeds for FDDWT. The simulation results show that the amount of combined load has an apparent effect on the contact load distribution along the TDIRB raceways and flanges in both rows. Furthermore, the slight change of tilted misalignment has a great influence on the contact load distribution. In addition, the slight angular misalignment easily produces noncontact zone for the bearing raceway in both rows, which is significantly disadvantage for the external load uniform transmitting to each roller.

Karimi, M, Croaker, P, Peters, H, Marburg, S, Skvortsov, A & Kessissoglou, N 1970, 'Vibro-acoustic response of a flat plate under turbulent boundary layer excitation', INTER-NOISE and NOISE-CON congress and conference proceedings (INCE), NOVEM 2018 – Noise and Vibration Emerging Methods, Institute of Noise Control Engineering, Ibiza, Spain, pp. 133-139.

Katuwandeniya, K, Ranasinghe, R, Dantanarayana, L, Dissanayake, G & Liu, D 1970, 'Calibration of a Rotating Laser Range Finder using Intensity Features.', ICARCV, International Conference on Control, Automation, Robotics and Vision, IEEE, Singapore, Singapore, pp. 228-234.
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© 2018 IEEE. This paper presents an algorithm for calibrating a '3D range sensor' constructed using a two-dimensional laser range finder (LRF), that is rotated about an axis using a motor to obtain a three-dimensional point cloud. The sensor assembly is modelled as a two degree of freedom open kinematic chain, with one joint corresponding to the axis of the internal mirror in the LRF and the other joint set along the axis of the motor used to rotate the body of the LRF. In the application described in this paper, the sensor unit is mounted on a robot arm used for infrastructure inspection. The objective of the calibration process is to obtain the coordinate transform required to compute the locations of the 3D points with respect to the robot coordinate frame. Proposed strategy uses observations of a set of markers arbitrarily placed in the environment. Distances between these markers are measured and a metric multidimensional scaling is used to obtain the coordinates of the markers with respect to a local coordinate frame. Intensity associated with each beam point of a laser scan is used to locate the reflective markers in the 3D point cloud and a least squares problem is formulated to compute the relationship between the robot coordinate frame, LRF coordinate frame and the marker coordinate frame. Results from experiments using the robot, LRF combination to map a cavity inside a steel bridge structure are presented to demonstrate the effectiveness of the calibration process.

Lai, JCS, Oberst, S & Evans, TA 1970, 'Termites use vibrations to eavesdrop on predatory ants', INTER-NOISE 2018 - 47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering, Internoise 2018, Chicago, Illinois, USA..
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Animals detect many signal types, including light, chemicals, sound and vibrations, some of which come from their environment, some they produce themselves. Signals are used deliberately to communicate and can be detected by predators or parasites. The role of vibrational communication in predator-prey relationships has received limited attention. One such relationship is that between termites and ants, which often live in close proximity with evidence of this evolutionary arms race dating back millions of years ago. Apart from having soldiers to drum alarm signals and to slow down predators' attacks, termites rely on mechanisms to avoid being contacted and detected. However, being cryptic also limits their ability to explore and assess foraging sites. Our previous research shows that despite being blind, (a) termites use vibrations of their feeding to assess food size; and (b) the drywood secundus workers use vibrations to eavesdrop to discriminate their own kin from and avoid their main subterranean competitor, Coptotermes (Co.) acinaciformis. In this paper, we will discuss our recent results that Co. acinaciformis can detect its main predator, the ant Iridomyrmex pupureus, by detecting its footsteps of which the frequency and magnitude are similar to that of the alarm signal of Co. acinaciformis. The application of the engineering noise control principle to develop vibration-based termite control technologies will be discussed.

Lai, Y, Sutjipto, S, Clout, MD, Carmichael, MG & Paul, G 1970, 'GAVRe²: Towards Data-Driven Upper-Limb Rehabilitation with Adaptive-Feedback Gamification', 2018 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2018 IEEE International Conference on Robotics and Biomimetics (ROBIO), IEEE, Kuala Lumpur, Malaysia, pp. 164-169.
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This paper presents Game Adaptive Virtual Reality Rehabilitation (GAVRe2), a framework to augment upper limb rehabilitation using Virtual Reality (VR) gamification and haptic robotic manipulator feedback. GAVRe2 integrates independent systems in a modular fashion, connecting patients with therapists remotely to increase patient engagement during rehabilitation. GAVRe2 exploits VR capabilities to not only increase the productivity of therapists administering rehabilitation, but also to improve rehabilitation mobility for patients. Conventional rehabilitation requires face-to-face physical interactions in a clinical setting which can be inconvenient for patients. The GAVRe2 approach provides an avenue for rehabilitation in a domestic setting by remotely customizing a routine for the patient. Results are then reported back to therapists for data analysis and future training regime development. GAVRe2 is evaluated experimentally through a system that integrates a popular VR system, a RGB-D camera, and a collaborative industrial robot, with results indicating potential benefits for long-term rehabilitation and the opportunity for upper limb rehabilitation in a domestic setting.

Lammers, T, Tomidei, L & Regattieri, A 1970, 'What Causes Companies to Transform Digitally? An Overview of Drivers for Australian Key Industries', 2018 Portland International Conference on Management of Engineering and Technology (PICMET), 2018 Portland International Conference on Management of Engineering and Technology (PICMET), IEEE, Honolulu, HI, USA.
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© 2018 Portland International Conference on Management of Engineering and Technology, Inc. (PICMET). Business leaders and entrepreneurs are facing new challenges in the rapidly transforming digital economy. The benefits obtained by the employment of digital technologies are broadly acknowledged. However, decisions need to be made about which technologies to acquire and how to integrate them into the business. In order to do this efficiently, organizations and disruptors all over the world need to understand the key drivers of digital transformation that affect their operations and industries. In this paper, the outcomes of a systematic literature review are presented which identify the drivers for digital transformations across key industries-using the example of Australia and its five core industries of services, mining, manufacturing, agriculture and construction. Outcomes indicate that drivers for digital transformation vary significantly across different industries. However, some drivers such as 'environmental sustainability' were found to be important across most industries. The results contribute to current research in this field by providing a comprehensive overview of industry-specific transformation drivers. This will support decision-making for technology managers and provide the foundation for similar studies in other countries.

Lee, KMB, Lee, JJH, Yoo, C, Hollings, B & Fitch, R 1970, 'Active perception for plume source localisation with underwater gliders', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA Website, Lincoln, New Zealand, pp. 1-10.
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We consider the problem of localising an unknown underwater plume source in an energy-optimal manner. We first develop a specialised Gaussian process (GP) regression technique for estimating the source location given concentration measurements and an ambient flow field. Then, we use the GP upper confidence bound (GP-UCB) for active perception to choose sampling locations that both improve the estimate of the source and lead the glider to the correct source location. A trim-based FMT∗planner is then used to find the sequence of controls that minimise the energy consumption. We provide a theoretical guarantee on the performance of the algorithm, and demonstrate the algorithm using both artificial and experimental datasets.

LU, S, Oberst, S, Zhang, G & Luo, Z 1970, 'Comparing complex dynamics using machine learning-reconstructed attracting sets', Colloquium on Irregular Engineering Oscillations and Signal Processing, TUHH, Hamburg, Germany.

LU, S, Oberst, S, Zhang, G & Luo, Z 1970, 'Order patterns recurrence plots and new quantifications to unveil nonlinear dynamics from stochastic systems', International Conference on Time Series and Forecasting 2018, International Conference on Time Series and Forecasting 2018, Granada, Spain.

Lu, W & Liu, D 1970, 'A Frequency-Limited Adaptive Controller for Underwater Vehicle-Manipulator Systems Under Large Wave Disturbances', 2018 13th World Congress on Intelligent Control and Automation (WCICA), 2018 13th World Congress on Intelligent Control and Automation (WCICA), IEEE, Changsha, China, pp. 246-251.
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© 2018 IEEE. Standard adaptive control approaches may not be able to sufficiently stabilize underwater vehicle-manipulator systems (UVMSs) when wave disturbances are large, leading to high-frequency oscillations of large amplitude in its dynamic model parameters. Such parameters bring about undesired oscillations in the vehicle body control and state. This paper extends a frequency-limited adaptive control approach to the vehicle body. An auxiliary model is obtained from the approximated model through a low-pass filter and is used to reduce the problematic oscillations. The resultant stable vehicle body is a necessary premise for successful end-effector tracking. In addition, this paper proposes a sufficient condition of the control gains for guaranteed asymptotical stability of the controlled robotic system. Numerical simulations have demonstrated the effectiveness of the presented approach, compared to the standard adaptive control.

Luo, Q & Tong, L 1970, 'Optimal design of bi- And multi-stable compliant cellular structures', Proceedings of the ASME Design Engineering Technical Conference, ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, ASME, Quebec City, Quebec, Canada.
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This paper presents optimal design for nonlinear compliant cellular structures with bi- and multi-stable states via topology optimization. Based on the principle of virtual work, formulations for displacements and forces are derived and expressed in terms of stress and strain in all load steps in nonlinear finite element analysis. Optimization for compliant structures with bi-stable states is then formulated as: 1) to maximize the displacement under specified force larger than its critical one; and 2) to minimize the reaction force for the prescribed displacement larger than its critical one. Algorithms are developed using the present formulations and the moving iso-surface threshold method. Optimal design for a unit cell with bi-stable states is studied first, and then designs of multistable compliant cellular structures are discussed.

Mahdavi, F, Hossain, MI, Hayati, H, Eager, D & Kennedy, P 1970, 'Track Shape, Resulting Dynamics and Injury Rates of Greyhounds', Volume 13: Design, Reliability, Safety, and Risk, ASME 2018 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Pittsburgh, Pennsylvania, USA.
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A challenge for greyhound racing is optimizing the tracks to minimize the risk of injuries. The effects of different track design variables on greyhound injury rates has not been explored sufficiently. The purpose of this paper is to present some preliminary findings on the effect of greyhound racetrack design variables such as the track curvature and lure alignment. An analysis was carried out of two years of greyhound racing injury data from three different tracks in New South Wales, Australia. The data from before and after an intervention was introduced were compared. Variables in the study, which may affect\ the analysis were investigated to minimize the errors. The analysis showed that there is a reduction in injury rates for a longer lure arm in the tracks with short or no straight section. To verify the effect of track design variables on the greyhound dynamics a kinematic simulation of greyhound center of gravity was created. The simulation considered fundamental variables correlating directly with kinematics between the greyhound and the track. The simulation data showed that the rate of change in the rotation of the greyhound heading direction decreases when the track running path has a more gradual curvature. The result of the simulation showed excellent agreement with that of injury data analysis.

Melnikov, A, Quann, L, Alú, A, Oberst, S, Marburg, S & Powell, D 1970, 'Theory for Willis coupling prediction of acoustic meta-atoms', Symposium on Acoustic Metamaterials, Xatavia, Spain.

Moore, SI, Ruppert, MG & Yong, YK 1970, 'Arbitrary Placement of AFM Cantilever Higher Eigenmodes Using Structural Optimization', 2018 International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), 2018 International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), IEEE.
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Nguyen, TNL, Eager, D & Nguyen, HT 1970, 'Effect Of Compression Garments On Cardiovascular Function During Recovery Phase', 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Honolulu, HI, USA, pp. 2869-2872.
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© 2018 IEEE. The aim of this present research was to determine whether the cardiovascular function has been affected by wearing compression garments during the recovery phase. Fourteen subjects (men, n=7; women, n=7; 24.7 ± 4.5 years, 166.0 ± 7.6 cm; 60.9 ± 12.0 kg) completed a running protocol on a treadmill. Each subject participated in two running experiments, using either compression garments (CGs) or non- compression garments (NCGs) during exercise and 2 hours recovering time. Electrocardiogram (ECG) signals were collected during 2 hours recovery using wearable sensors. The present work indicated a statistically significant difference between CGs and NCGs from 90 minutes recovery onwards (p <0.05). ECG parameters showed some significant difference in heart rate (HR), ST and corrected QT (QTc) (p <0.05). Therefore, the cardiovascular function was positively influenced by the application of CGs during the recovery phase.

Nguyen, TNL, Eager, D & Nguyen, HT 1970, 'The Effectiveness Of Compression Garments On EEG During a Running Test', 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Honolulu, HI, USA, pp. 3032-3035.
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© 2018 IEEE. The specific purpose of this present paper was to investigate whether the EEG activity has been affected by wearing whole body compression garments during a running test. Ten subjects (men, n=5; women, n=5; age: 24.11 ± 4.48 years; height: 163.56 ± 7.70 cm; chest: 87.78 ± 6.92 cm; weight: 58.67 ± 10.96 kg; BMI: 21.77 ± 2.63 kg.m-2) completed a running protocol on a treadmill. Each subject participated in two running trials, wearing either a compression garment (CG) or a non-compression garment (NCG) during exercise. Electroencephalogram (EEG) signals were collected during exercise using wearable sensors. The present study revealed a statistically significant difference between CGs and NCGs in alpha, beta and theta power spectral density (p<0.05). Therefore, the brain activity was influenced by the application of CGs during the running test. This result would also recommends an application of CGs in training as well as in competition.

Oberst, S 1970, 'Nonlinear Dynamics: Towards a paradigm change via evidence-based complex dynamics modelling', Noise and Vibrations Emerging Methods, Ibiza, Spain.

Oberst, S, Baetz, J, Campbell, G, Lampe, F, Lai, JCS, Hoffmann, N & Morlock, M 1970, 'Vibro-acoustic and nonlinear analysis of cadavric femoral bone impaction for cavity preparation in hip implants', MATEC Web of Conferences, EDP Sciences.

Oberst, S, Baetz, J, Campbell, G, Lampe, F, Leis, JCS, Hoffmann, N & Morlock, M 1970, 'Vibro-acoustic and nonlinear analysis of cadavric femoral bone impaction in cavity preparations', INTERNATIONAL CONFERENCE ON ENGINEERING VIBRATION (ICOEV 2017), International Conference on Engineering Vibration (ICoEV), E D P SCIENCES, BULGARIA, Sofia, pp. 1-6.
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Owing to an ageing population, the impact of unhealthy lifestyle, or simply congenital or gender specific issues (dysplasia), degenerative bone and joint disease (osteoarthritis) at the hip pose an increasing problem in many countries. Osteoarthritis is painful and causes mobility restrictions; amelioration is often only achieved by replacing the complete hip joint in a total hip arthroplasty (THA). Despite significant orthopaedic progress related to THA, the success of the surgical process relies heavily on the judgement, experience, skills and techniques used of the surgeon. One common way of implanting the stem into the femur is press fitting uncemented stem designs into a prepared cavity. By using a range of compaction broaches, which are impacted into the femur, the cavity for the implant is formed. However, the surgeon decides whether to change the size of the broach, how hard and fast it is impacted or when to stop the excavation process, merely based on acoustic, haptic or visual cues which are subjective. It is known that non-ideal cavity preparations increase the risk of peri-prosthetic fractures especially in elderly people. This study reports on a simulated hip replacement surgery on a cadaver and the analysis of impaction forces and the microphone signals during compaction. The recorded transient signals of impaction forces and acoustic pressures (≈ 80 µs - 2 ms) are statistically analysed for their trend, which shows increasing heteroscedasticity in the force-pressure relationship between broach sizes. TIKHONOV regularisation, as inverse deconvolution technique, is applied to calculate the acoustic transfer functions from the acoustic responses and their mechanical impacts. The extracted spectra highlight that system characteristics altered during the cavity preparation process: in the high-frequency range the number of resonances increased with impacts and broach size. By applying nonlinear time series analysis the system dynamics increase in compl...

Oberst, S, Lai, JCS & Evans, TA 1970, 'Excitation signal extraction of ant walking pattern under the influence of noise using a biomechanical bipedal mathematical model', 2nd International Symposium on Biotremology, San Michele all’Adige, Italy.

Oberst, S, Lim, S, Romão, AC, Lai, JCS, Stender, M, Hoffmann, NP & Evans, TA 1970, 'A coupled mono-bipedal biomechanical surrogate model to mimic ants walking and running gait analysed using recurrence plot quantification analysis', Colloquium on Irregular Oscillations and Signal Processing,, Hamburg, Germany.

Patten, T, Zillich, M & Vincze, M 1970, 'Action Selection for Interactive Object Segmentation in Clutter', 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE.
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Ranasinghe, R, Dissanayake, G & Liu, D 1970, 'Sensing for autonomous navigation inside steel bridges', 2018 IEEE SENSORS, 17th IEEE SENSORS Conference, IEEE, New Delhi, INDIA, pp. 1511-1514.

Ranasinghe, R, Dissanayake, G & Liu, D 1970, 'Sensing for Autonomous Navigation Inside Steel Bridges', 2018 IEEE SENSORS, 2018 IEEE Sensors, IEEE, New Delhi, India, pp. 1-4.
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© 2018 IEEE. The main contribution of this paper is a strategy to build a map of a bridge structure and estimate the precise location of a robot within it. In particular, the focus is on the autonomous navigation of a robot inside the steel arches that support the Sydney Harbour Bridge. A two dimensional laser range finder sensor, rotated about an axis perpendicular to its spin axis is used to capture the geometry of the environment in the form of a set of three-dimensional points; a point cloud. First, the approximate robot location is estimated by exploiting the fact that the environment predominantly consists of planes. Using this location estimate as an initial guess, the iterative closest point (ICP) algorithm is used to align point clouds obtained from nearby locations. Results from the ICP, together with a simultaneous localisation and mapping algorithm is then used to obtain accurate estimates of the locations of all the poses from where information is gathered, as well as a complete map of the environment. Results from experiments are used to demonstrate the effectiveness of proposed techniques.

Ruppert, MG & Yong, YK 1970, 'Design of Hybrid Piezoelectric/Piezoresistive Cantilevers for Dynamic-mode Atomic Force Microscopy', 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), IEEE.
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Ruppert, MG, Harcombe, DM, Moore, SI & Fleming, AJ 1970, 'Direct Design of Closed-loop Demodulators for Amplitude Modulation Atomic Force Microscopy', 2018 Annual American Control Conference (ACC), 2018 Annual American Control Conference (ACC), IEEE.
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Saha, SC, Islam, MS & Luo, Z 1970, 'Ultrafine particle transport and deposition in the upper airways of a CT-based realistic lung', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018.
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© 2018 Australasian Fluid Mechanics Society. All rights reserved. The understanding of the toxic pollutant particles transport and deposition is important for dosimetry and respiratory health effects analysis. The studies over the last few decades for ultrafine particle transport and deposition improves the understanding of the drug-aerosol impacts in the extrathoracic airways. A limited number of studies has also considered upper airways and almost all of those studies used the non-realistic smooth surface for upper airway model. However, the smooth surface anatomical model is far from the realistic lung and it is important to consider realistic lung model for better prediction of ultrafine particle deposition. This study aims to simulate the ultrafine particle transport and deposition in the upper airways of a highly asymmetric CT-based model. The anatomically explicit digital airway model is generated from the high-resolution CT data of a healthy adult. Unstructured tetrahedral mesh throughout the geometry and fine inflation layer mesh near the wall is generated. Euler-Lagrange (E-L) approach and ANSYS Fluent solver (18.2) are used to investigate the ultrafine particle transport and deposition. A wide range of diameter (1 ≤ nm ≤ 1000) and different flow rates are considered for the ultrafine particle simulation. Pressure drop is calculated for right and left lobes which might be helpful for the therapeutic purpose of the asthma patient. The numerical study shows that the deposition efficiency in the right lung and the left lung is different for dissimilar flow rates, which could help the health risk assessment of the respiratory diseases and eventually could help the targeted drug delivery system.

Saha, SC, Islam, MS & Luo, Z 1970, 'Ultrafine particle transport and deposition in the upper airways of a CT-based realistic lung', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018.
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© 2018 Australasian Fluid Mechanics Society. All rights reserved. The understanding of the toxic pollutant particles transport and deposition is important for dosimetry and respiratory health effects analysis. The studies over the last few decades for ultrafine particle transport and deposition improves the understanding of the drug-aerosol impacts in the extrathoracic airways. A limited number of studies has also considered upper airways and almost all of those studies used the non-realistic smooth surface for upper airway model. However, the smooth surface anatomical model is far from the realistic lung and it is important to consider realistic lung model for better prediction of ultrafine particle deposition. This study aims to simulate the ultrafine particle transport and deposition in the upper airways of a highly asymmetric CT-based model. The anatomically explicit digital airway model is generated from the high-resolution CT data of a healthy adult. Unstructured tetrahedral mesh throughout the geometry and fine inflation layer mesh near the wall is generated. Euler-Lagrange (E-L) approach and ANSYS Fluent solver (18.2) are used to investigate the ultrafine particle transport and deposition. A wide range of diameter (1 ≤ nm ≤ 1000) and different flow rates are considered for the ultrafine particle simulation. Pressure drop is calculated for right and left lobes which might be helpful for the therapeutic purpose of the asthma patient. The numerical study shows that the deposition efficiency in the right lung and the left lung is different for dissimilar flow rates, which could help the health risk assessment of the respiratory diseases and eventually could help the targeted drug delivery system.

Saha, SC, Islam, MS & Luo, Z 1970, 'Ultrafine particle transport and deposition in the upper airways of a CT-based realistic lung', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018.
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The understanding of the toxic pollutant particles transport and deposition is important for dosimetry and respiratory health effects analysis. The studies over the last few decades for ultrafine particle transport and deposition improves the understanding of the drug-aerosol impacts in the extrathoracic airways. A limited number of studies has also considered upper airways and almost all of those studies used the non-realistic smooth surface for upper airway model. However, the smooth surface anatomical model is far from the realistic lung and it is important to consider realistic lung model for better prediction of ultrafine particle deposition. This study aims to simulate the ultrafine particle transport and deposition in the upper airways of a highly asymmetric CT-based model. The anatomically explicit digital airway model is generated from the high-resolution CT data of a healthy adult. Unstructured tetrahedral mesh throughout the geometry and fine inflation layer mesh near the wall is generated. Euler-Lagrange (E-L) approach and ANSYS Fluent solver (18.2) are used to investigate the ultrafine particle transport and deposition. A wide range of diameter (1 ≤ nm ≤ 1000) and different flow rates are considered for the ultrafine particle simulation. Pressure drop is calculated for right and left lobes which might be helpful for the therapeutic purpose of the asthma patient. The numerical study shows that the deposition efficiency in the right lung and the left lung is different for dissimilar flow rates, which could help the health risk assessment of the respiratory diseases and eventually could help the targeted drug delivery system.

Schmitt, J & Deuse, J 1970, 'Similarity-search and Prediction Based Process Parameter Adaptation for Quality Improvement in Interlinked Manufacturing Processes', 2018 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM), 2018 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM), IEEE, Thailand, pp. 700-704.
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© 2018 IEEE. Due to the steadily increasing global competition, manufacturing companies are forced to constantly improve their products and processes. In this context, real-time process adaptation based on inline quality monitoring using predictive data mining techniques presents a promising approach to sustainably increase manufacturing process efficiency and improve product quality. This paper presents an approach to improve process and product quality in manufacturing through process parameter adaptations utilizing quality prediction models and similarity search algorithms. The approach enables a data-driven decision support for process control in interlinked manufacturing processes.

Seong, H, Choi, H, Son, H & Kim, C 1970, 'Image-based 3D Building Reconstruction Using A-KAZE Feature Extraction Algorithm', Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC), 34th International Symposium on Automation and Robotics in Construction, International Association for Automation and Robotics in Construction (IAARC), Germany, pp. 1052-1052.
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© ISARC 2018 - 35th International Symposium on Automation and Robotics in Construction and International AEC/FM Hackathon: The Future of Building Things. All rights reserved. Sensor technologies play a significant role in monitoring the health conditions of urban sewer assets. Currently, the concrete sewer systems are undergoing corrosion due to bacterial activities on the concrete surfaces. Therefore, water utilities use predictive models to estimate the corrosion by using observations such as relative humidity or surface moisture conditions. Surface moisture conditions can be estimated by electrical resistivity based moisture sensing. However, the measurements of such sensors are influenced by the proximal presence of reinforcing bars. To mitigate such e ects, the moisture sensor needs to be optimally oriented on the concrete surface. This paper focuses on developing a machine learning model for localizing the reinforcing bars inside the concrete through non-invasive measurements. This work utilizes a resistivity meter that works based on the Wenner technique to obtain electrical measurements on the concrete sample by taking measurements at di erent angles. Then, the measured data is fed to a Gaussian Markov Random Fields based spatial prediction model. The spatial prediction outcome of the proposed model demonstrated the feasibility of localizing the reinforcing bars with reasonable accuracy for the measurements taken at di erent angles. This information is vital for decision-making while deploying the moisture sensors in sewer systems.

Sick, N, Guertler, M, Kriz, A & Huizingh, E 1970, 'Tackling Wicked Problems with WickSprint: Approach, Applications, and Research Agenda', The ISPIM Innovation Conference – Innovation, The Name of The Game, Stockholm, Sweden.

Siddiki, MN-A-A, Molla, MM, Thohura, S & Saha, SC 1970, 'Lattice Boltzmann simulation of Non-Newtonian power-law fluid flows in a bifurcated channel', AIP Conference Proceedings, DISRUPTIVE INNOVATION IN MECHANICAL ENGINEERING FOR INDUSTRY COMPETITIVENESS: Proceedings of the 3rd International Conference on Mechanical Engineering (ICOME 2017), Author(s), BUET, Dhaka, BANGLADESH.
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Stender, M, Oberst, S & Hoffmann, NP 1970, 'Reconstruction of differential equations from time-series data for feature engineering and model identification', Colloquium on Irregular Oscillations and Signal Processing, Hamburg, Germany.

Strauss, P, Schmitz, M, Wostmann, R & Deuse, J 1970, 'Enabling of Predictive Maintenance in the Brownfield through Low-Cost Sensors, an IIoT-Architecture and Machine Learning', 2018 IEEE International Conference on Big Data (Big Data), 2018 IEEE International Conference on Big Data (Big Data), IEEE, Seattle, WA, USA, pp. 1474-1483.
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© 2018 IEEE. Predictive maintenance is one of the major drivers of Industry 4.0 as it can significantly reduce costs by improving overall equipment effectiveness and extending the remaining useful life of production machines. Most of the potential lies in the brownfield with old equipment where no sensors or connectivity are available. This paper shows how these production machines can be enabled for predictive maintenance by retrofitting with low-cost sensors, an Industrial-Internet-of-Things-architecture and machine learning. An industrial implementation on a heavy lift Electric Monorail System at the BMW Group will be shown.

Taghipour, R, Abdo, P & Huynh, BP 1970, 'Effect of Wind Speed on Ventilation Flow Through a Two Dimensional Room Fitted With a Windcatcher', Volume 7: Fluids Engineering, ASME 2018 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Pittsburgh, PA, USA.
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Natural ventilation is the process of supplying and removing air through an indoor space by natural means. Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment by decreasing moisture content in the air and reducing pollutants concentration. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns aimed at helping wind to channel down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of different wind speeds on the total air flow captured by different inlet designs is investigated. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a two dimensional room fitted with a windcatcher applying wind speeds from 1 m/s up to 14 m/s and based on different inlet designs such as a uniform inlet, a divergent inlet and a bulging-convergent inlet.

Thiyagarajan, K, Kodagoda, S, Nguyen, LV & Wickramanayake, S 1970, 'Gaussian Markov Random Fields for Localizing Reinforcing Bars in Concrete Infrastructure', Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC), 34th International Symposium on Automation and Robotics in Construction, International Association for Automation and Robotics in Construction (IAARC).
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Tran, A, Liu, D, Ranasinghe, R & Carmichael, M 1970, 'A Method for Quantifying a Robot’s Confidence in its Human Co-worker in Human-Robot Cooperative Grit-Blasting', 50th International Symposium on Robotics, ISR 2018, International Symposium on Robotics, Munich, pp. 474-481.
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In cooperative Human-Robot operations with physical contact, the human is generally in control while the robot assists the human. However, if the performance of the human were to decrease due to factors such as fatigue or distractions, there should be a mechanism that allows the robot to measure the performance of human operator and intervene in the interaction if needed. This becomes more important in physical Human-Robot Interactions such as cooperative grit-blasting, as the safety of the human may be affected if their performance decreases. In this work, a method for measuring the confidence of a robot in its human operator is presented. This method is then verified in a Human-Robot cooperative grit-blasting operation.

Tran, A, Liu, D, Ranasinghe, R & Carmichael, M 1970, 'Identifying Human Hand Orientation around a Cylindrical Handlebar for physical Human-Robot Interaction', 50th International Symposium on Robotics, ISR 2018, International Symposium on Robotics, Munich, pp. 427-434.
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This paper is concerned with identifying the orientation of the human hand relative to a cylindrical handlebar. In physical Human-Robot Interaction, a handlebar is commonly used as the point of contact between the human operator and the robot. Identifying the orientation of the operator’s hand provides the robot with additional information on how the operator interacts with the robot. A flexible sensor array composed of 160 pressure sensing cells was wrapped around a cylindrical handlebar. Grasping patterns of ten subjects was recorded. Support Vector Machine (SVM) and Bayesian Inference classifiers were implemented to identify the hand orientation of a subject relative to the handlebar. Principal Component Analysis (PCA) was used to reduce the number of features in the classification. Comparisons between the classifiers of SVM and Bayesian Inference, with/without PCA, were conducted for evaluating their accuracy. Two scenarios were used in the comparisons: in the first scenario, the training data and the test data were different but from the same subject; in the second scenario, the training data and the test data were from different subjects.

Trianni, A & Cagno, E 1970, 'Introduction to Panel 2: Sustainable production towards a circular economy', Eceee Industrial Summer Study Proceedings, pp. 151-152.

Trianni, A, Cagno, E & Nicosia, M 1970, 'Compressed air systems: Factors affecting the adoption of measures for improved efficiency', Eceee Industrial Summer Study Proceedings, European Council for an Energy Efficient Economy Summer Study, Belambra Presqu'île de Giens, France, pp. 171-180.
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The sustainability and competitiveness of industrial activities may strongly rely on increased energy efficiency. In that, compressed air could be one of the most expensive forms of energy in industry because of its low efficiency. Nonetheless, compressed air is widely used, and is considered as relevant in many facilities, accounting for even more than ten per cent of industrial electricity consumption in the EU, in US and in China. Moreover, it should be noted that the life-cycle cost of a compressed air system is mostly covered by the operating costs, so that most of the measures to lower energy consumption pay for themselves almost immediately, producing relevant monetary savings. Nevertheless, several studies show that the adoption rate of such Energy Efficiency Measures (EEMs) is still low. For this reason, we have carefully reviewed scientific and industrial literature over EEMs for Compressed Air Systems (CAS), so to get useful insights into the main factors leading to their adoption. Our study lays a good foundation for a novel framework aimed at describing and characterising EEMs in CAS, revealing that, so far scientific and industrial literature has mostly presented energy and economic factors, thus giving little room to other factors that still could be quite relevant for an effective EEM adoption, such as compatibility of the measure within the production system (e.g., adaptability to different conditions, presence of different pressure loads), complexity of the production system (e.g., accessibility for operational activities, expertise required for implementation), observability of the performance (e.g., impact on air quality and/or safety). The framework could result in a valuable tool offering different perspectives in the decision-making of industrial managers and technology suppliers, as well as industrial policy-makers.

Ulapane, N, Nguyen, L, Miro, JV & Dissanayake, G 1970, 'A solution to the inverse pulsed eddy current problem enabling 3D profiling', 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Wuhan, China, pp. 1267-1272.
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© 2018 IEEE. When a Pulsed Eddy Current (PEC) sensor assesses a metallic surface (i.e., a wall of finite thickness), the inverse problem involves quantification of the geometry and material properties of the wall. Once a PEC sensor is calibrated for a particular material, and the material under test happens to be considerably homogeneous, the inverse problem reduces to quantification of geometry alone. The state-of-the-art in the industry produces a quantification of this geometry only in the form of average wall thickness remaining underneath the sensor footprint, and produces a 2.5D map containing wall thickness information. Therefore, this paper contributes by proposing a solution that can jointly estimate the remaining wall thickness as well as lift-off (i.e., offset from the sensor to the surface of healthy material), in order to advance PEC sensing outputs by enabling estimation of wall condition in 3D. Since PEC maps are used as inputs for stress calculation and remaining life prediction of certain infrastructure like critical pipes, 3D profiles may become a richer form of input for such applications than 2.5D maps. Since PEC sensing is commonly used to assess ferromagnetic materials, this paper focuses on similar materials as well. The solution is demonstrated in simulation alone and future work should focus on experimental implementations.

Unicomb, J, Ranasinghe, R, Dantanarayana, L & Dissanayake, G 1970, 'A Monocular Indoor Localiser Based on an Extended Kalman Filter and Edge Images from a Convolutional Neural Network', 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Madrid, Spain, pp. 1-9.
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The main contribution of this paper is an extended Kalman filter (EKF)based algorithm for estimating the 6 DOF pose of a camera using monocular images of an indoor environment. In contrast to popular visual simultaneous localisation and mapping algorithms, the technique proposed relies on a pre-built map represented as an unsigned distance function of the ground plane edges. Images from the camera are processed using a Convolutional Neural Network (CNN)to extract a ground plane edge image. Pixels that belong to these edges are used in the observation equation of the EKF to estimate the camera location. Use of the CNN makes it possible to extract ground plane edges under significant changes to scene illumination. The EKF framework lends itself to use of a suitable motion model, fusing information from any other sensors such as wheel encoders or inertial measurement units, if available, and rejecting spurious observations. A series of experiments are presented to demonstrate the effectiveness of the proposed technique.

Valls, MJ, Hunt, D, Ulapane, N & Behrens, M 1970, 'Field and Service Robotics', Field and Service Robotics: Results of the 11th International Conference, Conference on Field and Service Robotics, Springer International Publishing, Zurich, pp. 319-334.
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Virgona, A, Alempijevic, A & Vidal-Calleja, TA 1970, 'Socially Constrained Tracking in Crowded Environments Using Shoulder Pose Estimates.', ICRA, IEEE International Conference on Robotics and Automation, IEEE, Brisbane, QLD, Australia, pp. 1-9.
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© 2018 IEEE. Detecting and tracking people is a key requirement in the development of robotic technologies intended to operate in human environments. In crowded environments such as train stations this task is particularly challenging due the high numbers of targets and frequent occlusions. In this paper we present a framework for detecting and tracking humans in such crowded environments in terms of 2D pose (x, y, θ). The main contributions are a method for extracting pose from the most visible parts of the body in a crowd, the head and shoulders, and a tracker which leverages social constraints regarding peoples orientation, movement and proximity to one another, to improve robustness in this challenging environment. The framework is evaluated on two datasets: one captured in a lab environment with ground truth obtained using a motion capture system, and the other captured in a busy inner city train station. Pose errors are reported against the ground truth and the tracking results are then compared with a state-of-the-art person tracking framework.

Wang, J, Song, J, Zhao, L & Huang, S 1970, 'A Submap Joining Based RGB-D SLAM Algorithm Using Planes as Features', 11th Conference on Field and Service Robotics (FSR 2017), 11th Conference on Field and Service Robotics (FSR 2017), Springer International Publishing, Zurich, Switzerland, pp. 367-382.
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Wang, T, Lu, W & Liu, D 1970, 'A Case Study: Modeling of A Passive Flexible Link on A Floating Platform for Intervention Tasks', 2018 13th World Congress on Intelligent Control and Automation (WCICA), 2018 13th World Congress on Intelligent Control and Automation (WCICA), IEEE, Changsha, China, pp. 187-193.
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© 2018 IEEE. This paper focuses on modeling of a robotic system consisting of a floating platform and a passive flexible-link, which is subjected to three-dimensional large bending deformation during intervention tasks. It investigates the feasibility and efficacy of the quasi-Lagrangian approach and the Euler-Bernoulli beam assumption in modeling this system. Simulations and experiments were conducted to evaluate the model. Then the contact force was calculated with given external input force along with the pose and velocities of the robot, which is validated by the measurements obtained from force-torque sensors. It also found that the accelerations calculated from the model have some deviation from the results obtained from a tracking system.

Wang, T, Lu, W & Liu, D 1970, 'Excessive disturbance rejection control of autonomous underwater vehicle using reinforcement learning', Australasian Conference on Robotics and Automation, ACRA, 2018 Australasian Conference on Robotics and Automation, Lincoln, New Zealand.
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Small Autonomous Underwater Vehicles (AUV) in shallow water might not be stabilized well by feedback or model predictive control. This is because wave and current disturbances may frequently exceed AUV thrust capabilities and disturbance estimation and prediction models available are not sufficiently accurate. In contrast to classical model-free Reinforcement Learning (RL), this paper presents an improved RL for Excessive disturbance rejection Control (REC) that is able to learn and utilize disturbance behaviour, through formulating the disturbed AUV dynamics as a multi-order Markov chain. The unobserved disturbance behaviour is then encoded in the AUV state-action history of fixed length, its embeddings are learned within the policy optimization. The proposed REC is further enhanced by a base controller that is pre-trained on iterative Linear Quadratic Regulator (iLQR) solutions for a reduced AUV dynamic model, resulting in hybrid-REC. Numerical simulations on pose regulation tasks have demonstrated that REC significantly outperforms a canonical controller and classical RL, and that the hybrid-REC leads to more efficient and safer sampling and motion than REC.

Wight, NM & Bennett, NS 1970, 'Experimental up-scaling of thermal conductivity reductions in silicon by vacancy-engineering: From the nano- to the micro-scale', Materials Today: Proceedings, European Conference on Thermoelectrics, Elsevier BV, Lisbon, Portugal, pp. 10211-10217.
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© 2017 Elsevier Ltd. All rights reserved. A method to reduce the thermal conductivity in Si thin-films by at least an order of magnitude is shown, successfully demonstrating the up-scaling of this technique from Si nano-films. High energy self implantation of Si is used to create a supersaturation of lattice vacancy concentrations that remain following post implant rapid thermal annealing producing a disruption in phonon mode thermal transport. This method demonstrates an approach for micro-harvesting thermoelectric device applications without the difficulties faced for dimensional up-scaling in alternative Si thermoelectric approaches. Challenges surrounding the thermal budget required for post implant dopant activation in p-Type Si are also shown.

Williams, PT, Hill, J, Thomson, J & Kirby, R 1970, 'The impact of design details on large silencer performance', INTER-NOISE 2018 - 47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering.
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Large silencers are commonly used in harsh environments where the design must consider high flow-rates, temperatures and stresses. This can impact on the construction of both the silencer baffle and the required support structure. Changes to the silencer design may include gaps between elements to allow for thermal expansion, support structures that can obstruct the air-path and extra protection for the porous insulation. Typical prediction models do not account for such factors and their effect on the overall performance of the silencer is not commonly known. In this paper numerical models using the finite element method are used to compare the effect of such details on the silencer insertion loss. The results of these predictions are compared to measured data and used to provide understanding as to the magnitude of the uncertainty typical design details may introduce.

Yu, J, Xiang, L, Ji, J, Miao, Z & Zhou, J 1970, 'Adaptive Region Tracking Control for Robot Manipulator Systems with Uncertain Kinematics and Dynamics', 2018 37th Chinese Control Conference (CCC), 2018 37th Chinese Control Conference (CCC), IEEE, Wuhan, China, pp. 2909-2914.
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© 2018 Technical Committee on Control Theory, Chinese Association of Automation. This paper studies the region tracking control problem of robot manipulator systems modeled by Lagrangian dynamics with uncertain kinematics and dynamics. By introducing a novel sliding mode, an adaptive controller is constructed to make the robot manipulator reach and track a desired dynamic region. Furthermore, a simple yet generic criterion on the region tracking control problem for robot manipulator systems is derived. It is shown that the robot end-effector can be able to reach in the desired dynamic region with the proposed controller in the presence of the uncertain kinematics and dynamics parameters. Based on the investigation, we revisit the region tracking problem with different control methodologies, to gain a brand-new understanding in the region tracking control problem. Finally, simulation results are presented to demonstrate the effectiveness of the theoretical results.

Zhang, Y, Zhang, T & Huang, S 1970, 'Comparison of EKF based SLAM and optimization based SLAM algorithms', 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Wuhan, China, pp. 1308-1313.
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© 2018 IEEE. This paper compares the recent developed state-of-the-art extended Kalman filter (EKF) based simultaneous localization and mapping (SLAM) algorithm, namely, invariant EKF SLAM, with the nonlinear least squares optimization based SLAM algorithms. Simulations in 1D, 2D, and 3D are used to evaluate the invariant EKF SLAM algorithm. It is demonstrated that in most 2D/3D scenarios with practical noise levels, the accuracy of invariant EKF is very close to that of nonlinear least squares optimization based SLAM. In the simple 1D case, the Kalman filter results and the linear least squares results are exactly the same (for any noise levels) due to the linear motion model and linear observation model involved.

Zhang, Z, Oberst, S & Lai, JCS 1970, 'Instability analysis of brake squeal with uncertain contact conditions', 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, International Congress on Sound and Vibration, Hiroshima, Japan, pp. 4031-4038.
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Brake squeal, as a phenomenon of friction-induced self-excited vibrations, has been a noise, vibration and harshness (NVH) problem for the automotive industry due to warranty-related claims and customer dissatisfaction. Intensive research in the past two decades have provided insight into a number of mechanisms that trigger brake squeal. However, brake squeal is a transient and nonlinear phenomenon and many determining factors are not known precisely such as material properties, operating conditions (brake pad pressure and temperature, speed), contact conditions between pad and disc, and friction. As a result, reliable prediction of brake squeal propensity is difficult to achieve and extensive noise dynamometer testings are still required to identify problematic frequencies for the development and validation of countermeasures. Here, the influence of uncertainties in friction modelling and contact conditions on friction-induced self-excited vibrations of a 3 x 3 coupled friction oscillators model is examined by combining the linear Complex Eigenvalue Analysis (CEA) method widely used in industry with a stochastic approach that incorporates these uncertainties. It has been found that unstable vibration modes with consistently high occurrence of instability independent of the contact area, friction modelling and sliding speed could be identified. Such unstable modes are considered to be robustly unstable and are most likely to produce squeal. An example is given to illustrate how instability countermeasures could be designed by repeating the uncertainty analysis for these robustly unstable modes. These results highlight the potential of reliable prediction of brake squeal propensity in a full brake-system using a stochastic approach with the CEA.

Zhao, J, Huang, S & Zhao, L 1970, 'Constrained Gaussian mixture models based scan matching method', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, New Zealand, pp. 1-8.
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This paper presents a Gaussian mixture model (GMM) based robust scan matching method which implements GMM to represent 2D scan points and improves the accuracy of scan matching. The proposed method transfers each new scan to GMM first, exploiting the covariance of every GMM component to represent scan points. Compared with the conventional GMM based method of scan matching, our technique implements GMM similarity comparison to evaluate the overlaps between scans. In order to get rid of the poor convergence due to the inaccurate initial value given to the iteration process, we proposed a geometry-constraint-based GMM similarity calculation method, which is one contribution of this paper. Another contribution is we propose a dynamic scale factor making the cost function more adapted to different initial value. Experiments on simulated data are employed and the results indicate that our method is able to enlarge the valid range of initial value and accumulate small errors after sequential matchings.

Zhao, S, Cheng, E, Qiu, X, Burnett, I & Liu, JCC 1970, 'Experimental investigations on the wind noise reduction of semi-spherical metal mesh windscreens', 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, pp. 288-295.
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The accuracy of noise measurements in the presence of flow is affected by wind noise, which is the pseudo sound generated on the microphone by turbulent flow. In outdoor acoustic measurement, porous windscreens are usually installed on the microphones to reduce the wind noise. In strong windy conditions, an additional large secondary shell windscreen is used to further mitigate the wind effect. This paper performs a systematic experimental study of semi-spherical shell windscreens. The effects of the windscreen size, multi-layer windscreens and fabric coverings on both the wind noise reduction and insertion loss are investigated. For single-layer windscreens without coverings, the insertion loss is below 0.4 dB and the maximum wind noise reduction is achieved by the mid-sized windscreen of 20 cm diameter. Covering the single-layer windscreens with a thin and thick cloth is found to introduce additional 1.0 ~ 3.5 dB and 3.0 ~ 7.0 dB wind noise reduction, but also increases the insertion loss to 1.1 ~ 2.2 dB. The multilayer windscreens are found to be superior to the fabric coverings, improving the wind noise reduction while keeping the insertion loss small. The best performance is achieved by the five-layer windscreen, with an 18.2 dB wind noise reduction and a 0.6 dB insertion loss.

Eager, D 2018, UTS greyhound safety and welfare research update (Maitland), UTS.

Eager, D, Hayati, H & Hossain, MI University of Technology Sydney 2018, Mt Gambier Track Injury Analysis and Preliminary Design Report, no. 1, Sydney, Australia.

Eager, D, Hayati, H, Mahdavi, F, Hossain, MI, Stephenson, R & Thomas, N University of Technology Sydney 2018, Identifying optimal greyhound track design for greyhound safety and welfare-Phase II-Progress Report-1 January 2016 to 31 December 2017, Sydney, Australia.

Mahdavi, F, Hayati, H, Thomas, N & Eager, D 2018, A preliminary investigation into the injury rate for 6 and 8 dog starts, UTS.

Mahdavi, F, Hayati, H, Thomas, N & Eager, D 2018, Injury rates analysis for races with different number of starts By Fatemeh Mahdavi, Hasti Hayati and Prof David Eager 06 April 2018 University of, UTS.

Lammers, T, Petersen, M & Brockhaus, S 2018, 'Pushing the Digital Transformation of Logistics: A Tri-Continental Study of Regulatory Environments'.

LU, S, Zhang, G, Luo, Z & Oberst, S 2018, 'Order pattern recurrence plots unveiling determinism buried in noise'.

Oberst, S, Stender, M, Baetz, J, Campbell, G, Lampe, F, Lai, JCS, Morlock, M & Hoffmann, N 2018, 'Extracting differential equations from measured vibro-acoustic impulse responses in cavity preparation of total hip arthroplasty'.

Song, J, Wang, J, Zhao, L, Huang, S & Dissanayake, G 2018, 'MIS-SLAM: Real-time Large Scale Dense Deformable SLAM System in Minimal Invasive Surgery Based on Heterogeneous Computing'.