Barns, S, Balanant, MA, Sauret, E, Flower, R, Saha, S & Gu, Y 2017, 'Investigation of red blood cell mechanical properties using AFM indentation and coarse-grained particle method', BioMedical Engineering OnLine, vol. 16, no. 1.
View/Download from: Publisher's site
View description>>
© 2017 The Author(s). Background: Red blood cells (RBCs) deform significantly and repeatedly when passing through narrow capillaries and delivering dioxygen throughout the body. Deformability of RBCs is a key characteristic, largely governed by the mechanical properties of the cell membrane. This study investigated RBC mechanical properties using atomic force microscopy (AFM) with the aim to develop a coarse-grained particle method model to study for the first time RBC indentation in both 2D and 3D. This new model has the potential to be applied to further investigate the local deformability of RBCs, with accurate control over adhesion, probe geometry and position of applied force. Results: The model considers the linear stretch capacity of the cytoskeleton, bending resistance and areal incompressibility of the bilayer, and volumetric incompressibility of the internal fluid. The model's performance was validated against force-deformation experiments performed on RBCs under spherical AFM indentation. The model was then used to investigate the mechanisms which absorbed energy through the indentation stroke, and the impact of varying stiffness coefficients on the measured deformability. This study found the membrane's bending stiffness was most influential in controlling RBC physical behaviour for indentations of up to 200 nm. Conclusions: As the bilayer provides bending resistance, this infers that structural changes within the bilayer are responsible for the deformability changes experienced by deteriorating RBCs. The numerical model presented here established a foundation for future investigations into changes within the membrane that cause differences in stiffness between healthy and deteriorating RBCs, which have already been measured experimentally with AFM.
Benamú, M, Lacava, M, García, LF, Santana, M, Fang, J, Wang, X & Blamires, SJ 2017, 'Nanostructural and mechanical property changes to spider silk as a consequence of insecticide exposure', Chemosphere, vol. 181, pp. 241-249.
View/Download from: Publisher's site
Bennett, NS 2017, 'Thermoelectric performance in n‐type bulk silicon: The influence of dopant concentration and dopant species', physica status solidi (a), vol. 214, no. 7, pp. 1-5.
View/Download from: Publisher's site
View description>>
Silicon (Si) has received recent interest for thermoelectric (TE) applications. For all TE materials, accurately tuning the doping concentration remains the easiest way to maximise the thermoelectric figure‐of‐merit (ZT). This study investigates the thermoelectric properties at 300 K of n‐type Si as a function of both dopant concentration (N ∼1019–1020 cm−3) and dopant species (P, As and Sb), including measurements of electrical resistivity, thermal conductivity, Seebeck coefficient and Hall mobility. All properties were found to vary as a function of both doping concentration and species, leading to impacts on the ZT. The electrical resistivity was lowest for P‐doped Si and highest in Sb‐doped Si. For the Seebeck coefficient, the situation was reversed. The thermal conductivity was lowest for Sb‐doping and highest in P‐doped Si. In all cases As‐doping was the intermediate dopant. An optimum doping concentration was realized at a value of ∼6–7 × 1019cm−3, and is similar for both As‐ and P‐doped Si. For Sb‐doping, the optimum value is likely to be similar, but the highest doping in commercially available wafers was ∼4 × 1019cm−3. At 300 K, ZT ∼0.010 is achieved for P‐doped bulk Si, however the best overall value was for As‐doped Si, at ∼0.013. For Sb doping the best value is ∼0.012, though a higher value is likely to be possible, but only if doping levels approximately double the concentrations available for this current study can be achieved in starting substrates. These results provide a useful insight for researchers who are selecting a starting substrate for top‐down nano‐structuring approaches to Si thermoelectrics, where a wafer with optimised ZT is required.
Best, G, Martens, W & Fitch, R 2017, 'Path Planning With Spatiotemporal Optimal Stopping for Stochastic Mission Monitoring', IEEE Transactions on Robotics, vol. 33, no. 3, pp. 629-646.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. We consider an optimal stopping formulation of the mission monitoring problem, in which a monitor vehicle must remain in close proximity to an autonomous robot that stochastically follows a predicted trajectory. This problem arises in a diverse range of scenarios, such as autonomous underwater vehicles supervised by surface vessels, pedestrians monitored by aerial vehicles, and animals monitored by agricultural robots. The key problem characteristics we consider are that the monitor must remain stationary while observing the robot, robot motion is modeled in general as a stochastic process, and observations are modeled as a spatial probability distribution. We propose a resolution-complete algorithm that runs in a polynomial time. The algorithm is based on a sweep-plane approach and generates a motion plan that maximizes the expected observation time and value. A variety of stochastic models may be used to represent the robot trajectory. We present results with data drawn from real AUV missions, a real pedestrian trajectory dataset and Monte Carlo simulations. Our results demonstrate the performance and behavior of our algorithm, and relevance to a variety of applications.
Blamires, SJ, Hasemore, M, Martens, PJ & Kasumovic, MM 2017, 'Diet-induced covariation between architectural and physicochemical plasticity in an extended phenotype', Journal of Experimental Biology, vol. 220, no. Pt 5, pp. 876-884.
View/Download from: Publisher's site
View description>>
The adaptive benefits of extended phenotypic plasticity are imprecisely defined due to a paucity of experiments examining traits that are manipulable and measurable across environments. Spider webs are often used as models to explore the adaptive benefits of variations in extended phenotypes across environments. Nonetheless, our understanding of the adaptive nature of the plastic responses of spider webs is impeded when web architectures and silk physicochemical properties appear to co-vary. An opportunity to examine this co-variation is presented by modifying prey items while measuring web architectures and silk physiochemical properties. Here we performed two experiments to assess the nature of the association between web architectures and gluey silk properties when the orb web spider Argiope keyserlingi was fed a diet that varied in either mass and energy or prey size and feeding frequency. We found web architectures and gluey silk physicochemical properties to co-vary across treatments in both experiments. Specifically, web capture area co-varied with gluey droplet morphometrics, thread stickiness and salt concentrations when prey mass and energy were manipulated, and spiral spacing co-varied with gluey silk salt concentrations when prey size and feeding frequency were manipulated. We explained our results as A. keyserlingi plastically shifting its foraging strategy as multiple prey parameters simultaneously varied. We confirmed and extended previous work by showing that spiders use a variety of prey cues to concurrently adjust web and silk traits across different feeding regimes.
Cagno, E, Trianni, A, Spallina, G & Marchesani, F 2017, 'Drivers for energy efficiency and their effect on barriers: empirical evidence from Italian manufacturing enterprises', Energy Efficiency, vol. 10, no. 4, pp. 855-869.
View/Download from: Publisher's site
View description>>
© 2017, Springer Science+Business Media Dordrecht. Industrial activities are responsible for a significant share of both global delivered energy demand and CO2 emissions. Hence, a widespread adoption of energy-efficient technologies and practices represents a crucial means for sustainable production. Adopting a novel framework of drivers for energy efficiency describing the effect of drivers on barriers in the decision-making process steps and able to account for the nature of drivers and the stakeholders responsible for their promotion, we have performed an exploratory investigation into 61 manufacturing small- and medium-sized enterprises in Northern Italy. Our findings have highlighted the importance of information and economic drivers, showing the need for enterprises to be supported not only by public institutions but also by external stakeholders involved in the supply of energy-efficient technologies and practices such as industrial associations and groupings, as well as service and technology suppliers. Moreover, our study has highlighted an almost equal relevance of both internal and external drivers. According to our findings, the increase of awareness—generating the interest to energy issues and stimulated both by external and internal stakeholders—as well as financial issues have emerged as the most critical in the decision-making process to adopt an energy-efficient measure. A preliminary comprehension of the mechanisms relating drivers to barriers in the decision-making process brought additional value to the study, highlighting the most effective and specific means to overcome the existing barriers. We have also explored the effect of several firm characteristics, such as firm size and energy intensity offering suggestions for industrial decision-makers as well as policy-makers.
Cagno, E, Trianni, A, Spallina, G & Marchesani, F 2017, 'Erratum to: Drivers for energy efficiency and their effect on barriers: empirical evidence from Italian manufacturing enterprises', Energy Efficiency, vol. 10, no. 4, pp. 871-871.
View/Download from: Publisher's site
View description>>
© Springer Science+Business Media Dordrecht 2016. This paper was unfortunately published with error. The given name of one of the authors was incorrectly captured as “Vincenzo” when it should be “Giovanni.” Further, the email address should be corrected to giovanni.spallina@mail.polimi.it. This was then corrected and is not anymore present in the published copies of the article.
Carmichael, MG, Liu, D & Waldron, KJ 2017, 'A framework for singularity-robust manipulator control during physical human-robot interaction', The International Journal of Robotics Research, vol. 36, no. 5-7, pp. 861-876.
View/Download from: Publisher's site
View description>>
© 2017, The Author(s) 2017. Collaborative robot manipulators are being used to assist human workers performing physically intensive tasks. The finite reach of the manipulator often results in the robot being operated in proximity to kinematic singularity, negatively affecting the stability and performance of operation. Methods of controlling manipulators in the proximity of singularities and mitigating their effects on performance have been widely researched. However, little attention has been given to developing suitable methods for handling singularities specifically for applications where the manipulator physically interacts with a human operator. In these applications additional factors such as human comfort and interaction experience need to be considered. This work presents a framework for handling robotic singularities developed with the human operator in mind. Singularity robustness is achieved using a novel approach to dampen motion of the manipulator along singular directions. An exponential scaling shapes the damping to create a smooth behavior beneficial for physical human–robot interaction. The damping is applied asymmetrically depending on if the robot is heading towards or away from singular configurations, improving the interaction experience for the human operator. Additionally, bounded virtual forces are used to subtly guide the operator away from singular configurations. The proposed framework is validated in simulation and tested on an industrial manipulator.
Chen, J, Li, C, Ristovski, Z, Milic, A, Gu, Y, Islam, MS, Wang, S, Hao, J, Zhang, H, He, C, Guo, H, Fu, H, Miljevic, B, Morawska, L, Thai, P, LAM, YF, Pereira, G, Ding, A, Huang, X & Dumka, UC 2017, 'A review of biomass burning: Emissions and impacts on air quality, health and climate in China', Science of The Total Environment, vol. 579, pp. 1000-1034.
View/Download from: Publisher's site
View description>>
Biomass burning (BB) is a significant air pollution source, with global, regional and local impacts on air quality, public health and climate. Worldwide an extensive range of studies has been conducted on almost all the aspects of BB, including its specific types, on quantification of emissions and on assessing its various impacts. China is one of the countries where the significance of BB has been recognized, and a lot of research efforts devoted to investigate it, however, so far no systematic reviews were conducted to synthesize the information which has been emerging. Therefore the aim of this work was to comprehensively review most of the studies published on this topic in China, including literature concerning field measurements, laboratory studies and the impacts of BB indoors and outdoors in China. In addition, this review provides insights into the role of wildfire and anthropogenic BB on air quality and health globally. Further, we attempted to provide a basis for formulation of policies and regulations by policy makers in China.
Cheng, S, Yu, L, Zhang, D & Ji, J 2017, 'Consensus of multiple Euler-Lagrange systems using one Euler-Lagrange System’s velocity measurements', International Journal of Control, Automation and Systems, vol. 15, no. 1, pp. 450-456.
View/Download from: Publisher's site
View description>>
© 2016, Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg. This brief paper studies the stationary consensus of multiple Euler-Lagrange systems with nonlinear protocols. Two consensus protocols are given to guarantee that positions and velocities of multiple Euler-Lagrange systems reach consensus. Proposed protocols need only the relative position measurements and the velocity measurements of one Euler-Lagrange system. Finally, numerical simulations are given to illustrate the theoretical results.
Cheng, X, Jiang, Z, Wei, D, Hao, L, Wu, H, Xia, W, Zhang, X, Luo, S & Jiang, L 2017, 'Effects of surface preparation on tribological behaviour of a ferritic stainless steel in hot rolling', Wear, vol. 376-377, no. PART B, pp. 1804-1813.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier B.V. Some defects on the surface of carbon steel do not need to be removed before hot rolling because the surface will be vigorously oxidised in a reheating environment. Thus the defects can be minimised by oxidising and then removed by the de-scaling process. The defects on the surface of ferritic stainless steels, however, are not easily removed by oxidation when a high chromium concentration is used. In this paper, a ferritic stainless steel grade 445 was selected as a research material. The effects of different surface features on oxidation and tribological behaviour in the hot rolling process were investigated. Three surface states were prepared, namely, smooth surface, surface with 45° grinding marks and surface with oscillation marks. The samples were put into an electric furnace at 1100 °C for reheating. Hot rolling tests were carried out on a 2-high Hille 100 experimental rolling mill. Rolling forces were measured, and the coefficient of friction was calculated and compared under various rolling parameters. It was found that the original surfac e profiles with grinding marks were still maintained during oxidation. The original oxide scale on the surface with oscillation marks caused the formation of irregular oxide nodules and the spallation of the oxide scale. Surface morphology and the reduction in thickness had a significant impact on the oxide scale integrity and coefficient of friction in the hot rolling process.
Cheng, X, Wei, D, Jiang, Z & Jiang, L 2017, 'Analysis of oxide scale deformation and surface roughness characterisation in hot rolling of stainless steels', International Journal of Surface Science and Engineering, vol. 11, no. 3, pp. 241-241.
View/Download from: Publisher's site
View description>>
© 2017 Inderscience Enterprises Ltd. Stainless steels are iron-based alloys that contain a minimum of about 12% Cr. They have been classified by microstructure at room temperature. Two stainless steel grades 304 and 410L were studied in this paper. Hot rolling was performed on a Hille 100 experimental rolling mill under various reductions with consideration of the oxide scale thickness controlled by oxidation time. The experimental results show that the deformation behaviour of the oxide scale on the stainless steel 304 is sensitive to its thickness and exhibits higher resistance to be deformed. However, the reduction in thickness plays an important role in the uniformity of the oxide scale deformation for the stainless steel 410L. Friction coefficients were calculated and compared. Simulations results show that the reduction in thickness and initial surface roughness play roles on final surface roughness. Steel substrate surface is rougher than that of the oxide scale at different reductions.
Cui, H, Xu, F & Saha, SC 2017, 'Transition to unsteady natural convection flow in a prismatic enclosure of triangular section', International Journal of Thermal Sciences, vol. 111, pp. 330-339.
View/Download from: Publisher's site
View description>>
© 2016 Elsevier Masson SAS Natural convection in a prismatic enclosure of triangular section with the top cooling and the bottom heating is investigated using three dimensional (3D) numerical simulations for a wide range of Rayleigh numbers from 10 0 to 1.25 × 10 6 . The numerical result has been compared with the experiment. The development of natural convection flows in the cavity following sudden heating and cooling involves three stages: an initial stage, a transitional stage and a fully developed stage. Transition to unsteady natural convection flow in the fully developed stage, dependent on the Rayleigh number, is described. The flow structure including transversal and longitudinal rolls is characterized and the corresponding mechanism is discussed. The critical Rayleigh number for the transition to unsteady natural convection flow is obtained. The dependence of heat transfer on the Rayleigh number is quantified.
Du, Y, Li, H, Luo, Z & Tian, Q 2017, 'Topological design optimization of lattice structures to maximize shear stiffness', Advances in Engineering Software, vol. 112, pp. 211-221.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd To improve the poor shear performance of periodic lattice structure consisting of hexagonal unit cells, this study develops a new computational design method to apply topology optimization to search the best topological layout for lattice structures with enhanced shear stiffness. The design optimization problem of micro-cellular material is formulated based on the properties of macrostructure to maximize the shear modulus under a prescribed volume constraint using the energy-based homogenization method. The aim is to determine the optimal distribution of material phase within the periodic unit cell of lattice structure. The proposed energy-based homogenization procedure utilizes the sensitivity filter technique, especially, a modified optimal algorithm is proposed to evolve the microstructure of lattice materials with distinct topological boundaries. A high shear stiffness structure is obtained by solving the optimization model. Then, the mechanical equivalent properties are obtained and compared with those of the hexagonal honeycomb sandwich structure using a theoretical approach and the finite element method (FEM) according to the optimized structure. It demonstrates the effectiveness of the proposed method in this paper. Finally, the structure is manufactured, and then the properties are tested. Results show that the shear stiffness and bearing properties of the optimized lattice structure is better than that of the traditional honeycomb sandwich structure. In general, the proposed method can be effectively applied to the design of periodic lattice structures with high shear resistance and super bearing property.
Eskerod, P & Ang, K 2017, 'Stakeholder Value Constructs in Megaprojects: A Long-Term Assessment Case Study', Project Management Journal, vol. 48, no. 6, pp. 60-75.
View/Download from: Publisher's site
View description>>
By definition, megaprojects consume numerous resources and impact numerous people, even across generations; it is therefore important that they bring considerable value to their initiators and other stakeholders. Based on stakeholder value construct frameworks identified in the literature and a single case study of the construction and operations of an over 50-year-old American highway bridge, we identify ways to understand, classify, and express megaproject stakeholder value. The research links different stakeholder types to types of value constructs. Knowing which types of value constructs matter to different stakeholder types could potentially help project representatives communicate more efficiently and effectively.
Falque, R, Vidal-Calleja, T & Miro, J 2017, 'Defect Detection and Segmentation Framework for Remote Field Eddy Current Sensor Data', Sensors, vol. 17, no. 10, pp. 2276-2276.
View/Download from: Publisher's site
View description>>
© 2017 by the authors; Licensee MDPI, Basel, Switzerland. Remote-Field Eddy-Current (RFEC) technology is often used as a Non-Destructive Evaluation (NDE) method to prevent water pipe failures. By analyzing the RFEC data, it is possible to quantify the corrosion present in pipes. Quantifying the corrosion involves detecting defects and extracting their depth and shape. For large sections of pipelines, this can be extremely time-consuming if performed manually. Automated approaches are therefore well motivated. In this article, we propose an automated framework to locate and segment defects in individual pipe segments, starting from raw RFEC measurements taken over large pipelines. The framework relies on a novel feature to robustly detect these defects and a segmentation algorithm applied to the deconvolved RFEC signal. The framework is evaluated using both simulated and real datasets, demonstrating its ability to efficiently segment the shape of corrosion defects.
From, CS, Sauret, E, Armfield, SW, Saha, SC & Gu, YT 2017, 'Turbulent dense gas flow characteristics in swirling conical diffuser', Computers & Fluids, vol. 149, pp. 100-118.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Diffusers placed at the exit of turbines are essential to recover pressure and increase turbine efficiency. This increase of efficiency is critical for the overall cycle efficiency of renewable power cycles based on low temperature renewable resources. Optimising the performance of a conical diffuser in renewable power cycles using high-density fluids can be established by examining the turbulence characteristics of both air considered as an ideal gas (IG) and R143a, a refrigerant with high-density in a non-ideal state, considered as a real gas (RG). Turbulence was firstly modelled and validated against experimental results from the ERCOFTAC swirling conical diffuser database and previous numerical results. The real gas thermodynamic and transport properties of refrigerant R143a were then obtained from the NIST REFPROP database. Investigating both RG and IG revealed that general trends remain, where the stronger wall components in RG help improve the diffuser performance. Furthermore, investigations regarding turbulence intensities indicated a clear effect on the flow behaviour for IG while being ineffective on the RG. The final application analysed the diffuser performance using the inlet conditions extracted directly from a potential radial-inflow turbine working with R143a. The change of conditions highlighted that radial components can be reduced, and thus the swirling number too. By implementing the first numerical study on real gas swirling conical diffuser, it was established that real gas flow regimes differ from the ones previously established for ideal gas, and thus preliminary flow regimes for R143a, specifically, are proposed.
Ge, XJ, Livesey, P, Wang, J, Huang, S, He, X & Zhang, C 2017, 'Deconstruction waste management through 3d reconstruction and bim: a case study', Visualization in Engineering, vol. 5, no. 1.
View/Download from: Publisher's site
View description>>
AbstractThe construction industry is responsible for 50% of the solid waste generated worldwide. Governments around the world formulate legislation and regulations concerning recycling and re-using building materials, aiming to reduce waste and environmental impact. Researchers have also been developing strategies and models of waste management for construction and demolition of buildings. The application of Building Information Modeling (BIM) is an example of this. BIM is emergent technology commonly used to maximize the efficiency of design, construction and maintenance throughout the entire lifecycle. The uses of BIM on deconstruction or demolition are not common; especially the fixtures and fittings of buildings are not considered in BIM models. The development of BIM is based on two-dimensional drawings or sketches, which may not be accurately converted to 3D BIM models. In addition, previous researches mainly focused on construction waste management. There are few studies about the deconstruction waste management focusing on demolition. To fill this gap, this paper aims to develop a framework using a reconstructed 3D model with BIM, for the purpose of improving BIM accuracy and thus developing a deconstruction waste management system to improve demolition efficiency, effective recycling and cost savings. In particular, the developed as-built BIM will be used to identify and measure recyclable materials, as well as to develop a plan for the recycling process.
Ghaffari Jadidi, M, Miro, JV & Dissanayake, G 2017, 'Warped Gaussian Processes Occupancy Mapping With Uncertain Inputs', IEEE Robotics and Automation Letters, vol. 2, no. 2, pp. 680-687.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. In this paper, we study extensions to the Gaussian processes (GPs) continuous occupancy mapping problem. There are two classes of occupancy mapping problems that we particularly investigate. The first problem is related to mapping under pose uncertainty and how to propagate pose estimation uncertainty into the map inference. We develop expected kernel and expected submap notions to deal with uncertain inputs. In the second problem, we account for the complication of the robot's perception noise using warped Gaussian processes (WGPs). This approach allows for non-Gaussian noise in the observation space and captures the possible nonlinearity in that space better than standard GPs. The developed techniques can be applied separately or concurrently to a standard GP occupancy mapping problem. According to our experimental results, although taking into account pose uncertainty leads, as expected, to more uncertain maps, by modeling the nonlinearities present in the observation space WGPs improve the map quality.
Halkon, BJ & Rothberg, SJ 2017, 'Reprint of: Taking laser Doppler vibrometry off the tripod: correction of measurements affected by instrument vibration', Optics and Lasers in Engineering, vol. 99, pp. 3-10.
View/Download from: Publisher's site
View description>>
© 2017. Laser Doppler vibrometers (LDVs) are now well-established as an effective non-contact alternative to traditional contacting transducers. Despite 30 years of successful applications, however, very little attention has been given to sensitivity to vibration of the instrument itself. In this paper, the sensitivity to instrument vibration is confirmed before development theoretically and experimentally of a practical scheme to enable correction of measurements for arbitrary instrument vibration. The scheme requires a pair of correction sensors with appropriate orientation and relative location, while using frequency domain processing to accommodate inter-channel time delay and signal integrations. Error reductions in excess of 30. dB are delivered in laboratory tests with simultaneous instrument and target vibration over a broad frequency range. Ultimately, application to measurement on a vehicle simulator experiencing high levels of vibration demonstrates the practical nature of the correction technique and its robustness in a challenging measurement environment.
Halkon, BJ & Rothberg, SJ 2017, 'Restoring high accuracy to laser Doppler vibrometry measurements affected by vibration of beam steering optics', Journal of Sound and Vibration, vol. 405, pp. 144-157.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Laser Doppler vibrometers are now well-established as an effective non-contact alternative to traditional contacting transducers. Wide-ranging applications include those where beam steering optics are required to reach locations that are difficult to access but no attention has yet been given to measurement sensitivity to the vibration of those optics. In this paper, a thorough mathematical treatment of this sensitivity to steering optic vibration and its correction is set out. A very practical scheme requiring a single correction measurement, from the back-surface of the mirror at the incidence point and aligned with the mirror normal, delivers an error reduction typically in excess of 30 dB. After validation in the laboratory, the scheme is then applied to a genuinely challenging measurement scenario on a single cylinder racing motorcycle. Correction is theoretically perfect for translational mirror vibrations but angular mirror vibrations require an adapted scheme using a triplet of accelerometers arranged around a circular path on the mirror back-surface and this is set out theoretically.
Halkon, BJ & Rothberg, SJ 2017, 'Taking laser Doppler vibrometry off the tripod: correction of measurements affected by instrument vibration', Optics and Lasers in Engineering, vol. 91, pp. 16-23.
View/Download from: Publisher's site
View description>>
© 2016 Elsevier Ltd Laser Doppler vibrometers (LDVs) are now well-established as an effective non-contact alternative to traditional contacting transducers. Despite 30 years of successful applications, however, very little attention has been given to sensitivity to vibration of the instrument itself. In this paper, the sensitivity to instrument vibration is confirmed before development theoretically and experimentally of a practical scheme to enable correction of measurements for arbitrary instrument vibration. The scheme requires a pair of correction sensors with appropriate orientation and relative location, while using frequency domain processing to accommodate inter-channel time delay and signal integrations. Error reductions in excess of 30 dB are delivered in laboratory tests with simultaneous instrument and target vibration over a broad frequency range. Ultimately, application to measurement on a vehicle simulator experiencing high levels of vibration demonstrates the practical nature of the correction technique and its robustness in a challenging measurement environment.
Hao, L, Wu, H, Wei, D, Cheng, X, Zhao, J, Luo, S, Jiang, L & Jiang, Z 2017, 'Wear and friction behaviour of high-speed steel and indefinite chill material for rolling ferritic stainless steels', Wear, vol. 376-377, pp. 1580-1585.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier B.V. In this paper, wear and friction behaviour of high-speed steel (HSS) and indefinite chill (IC) material for rolling a ferritic stainless steel were investigated on a tribometer. A disk specimen of the ferritic stainless steel-B445J1M was pre-oxidised at 1100 °C for 30 min, and then rotated against a pin at 500 °C for 30 min. The pin was made of HSS or IC material. It was found that the friction coefficient of the IC was lower than that of the HSS, but the mass loss of the HSS pin was less than that of the IC pin. The oxide scale of the disk was more easily worn out and attached on the HSS pin than that of the IC pin.
Hassan, M & Liu, D 2017, 'Simultaneous area partitioning and allocation for complete coverage by multiple autonomous industrial robots', Autonomous Robots, vol. 41, no. 8, pp. 1609-1628.
View/Download from: Publisher's site
View description>>
© 2017, Springer Science+Business Media New York. For tasks that require complete coverage of surfaces by multiple autonomous industrial robots, it is important that the robots collaborate to appropriately partition and allocate the surface areas amongst themselves such that the robot team’s objectives are optimized. An approach to this problem is presented, which takes into account unstructured and complex 3D environments, and robots with different capabilities. The proposed area partitioning and allocation approach utilizes Voronoi partitioning to partition objects’ surfaces, and multi-objective optimization to allocate the partitioned areas to the robots whilst optimizing robot team’s objectives. In addition to minimizing the overall completion time and achieving complete coverage, which are objectives particularly useful for applications such as surface cleaning, manipulability measure and joint’s torque are also optimized so as to help autonomous industrial robots to operate better in applications such as spray painting and grit-blasting. The approach is validated using six case studies that consist of comparative studies, complex simulated scenarios as well as real scenarios using data obtained from real objects and applications.
Hayati, H, Hosseini, SA & Rahmani, O 2017, 'Coupled twist–bending static and dynamic behavior of a curved single-walled carbon nanotube based on nonlocal theory', Microsystem Technologies, vol. 23, no. 7, pp. 2393-2401.
View/Download from: Publisher's site
View description>>
© 2016 Springer-Verlag Berlin Heidelberg The static and dynamic behavior of a curved single-walled carbon nanotube which is under twist–bending couple based on nonlocal theory is analyzed. The nonlocal theory is used to model the mechanical behavior of structure in small scale. The obtained differential equations are solved using a simply supported boundary condition and Navier analytical method. Moreover the twisted vibration and bending of curved nanotube is analyzed and also the armchair model is assumed in this study. The following parameters were studied in this paper: the effect of nonlocal parameter, the curved nanotube’s opening angel, the Young’s modulus and the mode number is studied. The results were verified with the previous literature which showed an excellent agreement. The results of this paper can be used as a benchmark for future investigations.
Henke, T, Weisner, K, Schulte, L & Deuse, J 2017, 'Planning framework to standardize the material supply for individual and small series of large scale products with many variants', ZWF Zeitschrift fuer Wirtschaftlichen Fabrikbetrieb, vol. 112, no. 12, pp. 873-876.
View/Download from: Publisher's site
View description>>
Since the demand of individual products rises, large scale product manufacturer need to offer a wide product range. Especially the material supply, whose planning and control is very complex and unstandardized, offers a high potential for optimization. Therefore within the research project “SySMaG” of the IPS (Dortmund) a planning framework will be developed, with which the existing potential for optimization in material supply can be harnessed in large scale product assembly in the near future.
Huang, S & Dissanayake, G 2017, 'Special Issue on Localization and Mapping in Challenging Environments', Robotics and Autonomous Systems, vol. 97, pp. 16-17.
View/Download from: Publisher's site
Islam, MS, Saha, SC, Sauret, E, Gemci, T & Gu, YT 2017, 'Pulmonary aerosol transport and deposition analysis in upper 17 generations of the human respiratory tract', Journal of Aerosol Science, vol. 108, pp. 29-43.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd The major problem in understanding the therapeutically targeted drug delivery system in the deeper airways of the human lung is the lack of adequate data of particle transport and deposition (TD) in the transitional and respiratory zones (deeper airways) of the human lung. An understanding of the morphometry of the pulmonary airways and the lungs forms the primary step in a study of pulmonary aerosol deposition. The present study is the first-ever approach to explore the pulmonary aerosol TD in a digital 17-generation human pulmonary airway model. The present numerical study achieved the lack of the particle TD data in the deeper airways of the human lung. This paper presents a 3-D (3-dimensional) CFD (Computational Fluid Dynamics) study of an anatomically realistic 17-generation lung bronchial tree model based on the high-resolution computer tomography (HRCT) data by Schmidt et al. (2004). Physical morphometry is necessary for sufficiently calculating air and particle dynamics in human pulmonary airways with available data on a large number of generations. A Lagrangian-based Discrete Phase Model (DPM) is used to study the particle TD in the 17-generation of the lung airways. The numerical results demonstrate that inertial impaction is dominant in the upper airways and a large percentage of particles is deposited in the upper airways. The numerical results also illustrate that a large percentage of smaller diameter particles leaves through the airway outlet boundary at the 17th generation irrespective of breathing patterns. The escaped particles are considered to continue to follow the airway flow field further downstream after the 17th generation till the 23rd generation and some of them will reach the alveolar sacs region. This computational model could potentially aid in overcoming the nanobiotechnology toxicity problem for drug delivery in the deeper airways.
Islam, MS, Saha, SC, Sauret, E, Gemci, T, Yang, IA & Gu, YT 2017, 'Ultrafine particle transport and deposition in a large scale 17-generation lung model', Journal of Biomechanics, vol. 64, pp. 16-25.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd To understand how to assess optimally the risks of inhaled particles on respiratory health, it is necessary to comprehend the uptake of ultrafine particulate matter by inhalation during the complex transport process through a non-dichotomously bifurcating network of conduit airways. It is evident that the highly toxic ultrafine particles damage the respiratory epithelium in the terminal bronchioles. The wide range of in silico available and the limited realistic model for the extrathoracic region of the lung have improved understanding of the ultrafine particle transport and deposition (TD) in the upper airways. However, comprehensive ultrafine particle TD data for the real and entire lung model are still unavailable in the literature. Therefore, this study is aimed to provide an understanding of the ultrafine particle TD in the terminal bronchioles for the development of future therapeutics. The Euler-Lagrange (E-L) approach and ANSYS fluent (17.2) solver were used to investigate ultrafine particle TD. The physical conditions of sleeping, resting, and light activity were considered in this modelling study. A comprehensive pressure-drop along five selected path lines in different lobes was calculated. The non-linear behaviour of pressure-drops is observed, which could aid the health risk assessment system for patients with respiratory diseases. Numerical results also showed that ultrafine particle-deposition efficiency (DE) in different lobes is different for various physical activities. Moreover, the numerical results showed hot spots in various locations among the different lobes for different flow rates, which could be helpful for targeted therapeutical aerosol transport to terminal bronchioles and the alveolar region.
Ji, J 2017, 'Stability of the coupled vibrations of work roll and strip in cold rolling process', Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, vol. 231, no. 7, pp. 1169-1181.
View/Download from: Publisher's site
View description>>
Undesirable vibrations that occurred in cold rolling mills, widely known as chatter, are studied in this article by considering the interaction of three types of vibrations, namely, the longitudinal vibration of the rolled strip and the torsional and vertical vibrations of the upper work roll. The dynamic component of rolling force is determined using the quasi-static model under the assumption that the changes in roll gap and strip tension produce the variation of rolling force. The coupled vibrations of the work roll and rolled strip are mathematically governed by a set of 3-degree-of-freedom non-linear equations. Under chatter conditions, a new variable is introduced to represent the motion of the quasi-neutral point. A stability criterion for the motion of the quasi-neutral point is developed by studying the eigenvalues of the corresponding characteristic equation of the linearized parts of the non-linear equations. The chatter stability can then be examined by evaluating the determinants of five matrices. Numerical examples are given to show the stable and unstable vibrations in the cold rolling process. The unstable vibration would lead to skidding phenomenon and even break the rolled strip. The results presented in this article provide new insights into the dynamic interaction of the coupled vibrations and the dynamics of the rolling process.
Ji, JC & Brown, T 2017, 'Periodic and Chaotic Motion of a Time-Delayed Nonlinear System Under Two Coexisting Families of Additive Resonances', International Journal of Bifurcation and Chaos, vol. 27, no. 05, pp. 1750066-1750066.
View/Download from: Publisher's site
View description>>
A time-delayed quadratic nonlinear mechanical system can exhibit two coexisting stable bifurcating solutions (SBSs) after two-to-one resonant Hopf bifurcations occur in the corresponding autonomous time-delayed system. One SBS is of small-amplitude and has the Hopf bifurcation frequencies (HBFs), while the other is of large-amplitude and contains the shifted Hopf bifurcation frequencies (the shifted HBFs). When the forcing frequency is tuned to be the sum of two HBFs or the sum of two shifted HBFs, two families of additive resonances can be induced in the forced response. The forced response under the additive resonance related to the HBFs can demonstrate periodic, quasi-periodic and chaotic motion. On the contrary, the forced response under the additive resonance associated with the shifted HBFs may exhibit period-three periodic motion and quasi-periodic motion. Bifurcation diagrams, time trajectories, frequency spectra, phase portraits and Poincaré sections are presented to show periodic, quasi-periodic, and chaotic motion of the time-delayed nonlinear system under the two families of additive resonances.
Ji, JC & Zhou, J 2017, 'Coexistence of two families of sub-harmonic resonances in a time-delayed nonlinear system at different forcing frequencies', Mechanical Systems and Signal Processing, vol. 93, pp. 151-163.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Two coexisting families of sub-harmonic resonances can be induced at different forcing frequencies in a time-delayed nonlinear system having quadratic nonlinearities. They occur in the region where two stable bifurcating periodic solutions coexist in the corresponding autonomous system following two-to-one resonant Hopf bifurcations of the trivial equilibrium. The forced response is found to demonstrate small- and large-amplitude quasi-periodic motion under the family of sub-harmonic resonances related to Hopf bifurcation frequencies, and large-amplitude periodic and quasi-periodic motion under the family of sub-harmonic resonances associated with the shifted Hopf bifurcation frequencies. The family of sub-harmonic resonances related to Hopf bifurcation frequencies may cease to exist with the loss of the initially established frequency relationship of sub-harmonic resonances when the magnitude of periodic excitation is beyond a certain value. This will lead to a jump phenomenon from small- to large-amplitude quasi-periodic motion. Bifurcation diagrams, time trajectories and frequency spectra are numerically obtained to characterize the sub-harmonic resonances of the time-delayed nonlinear system around the critical point of the resonant Hopf bifurcations.
Jiang, Z, Zhao, J, Lu, H, Wei, D, Manabe, K-I, Zhao, X, Zhang, X & Wu, D 2017, 'Influences of temperature and grain size on the material deformability in microforming process', International Journal of Material Forming, vol. 10, no. 5, pp. 753-764.
View/Download from: Publisher's site
View description>>
© 2016, Springer-Verlag France. This paper investigated the influences of temperature and grain size on the deformability of pure copper in micro compression process. Based on the dislocation theory, a constitutive model was proposed taking into account the influences of forming temperature, Hall-Petch relationship and surface layer model. Vacuum heat treatment was employed to obtain various grain sizes of cylindrical workpieces, and then laser heating method was applied to heat workpieces during microforming process. Finite element (FE) simulation was also performed, with simulated values agreed well with the experimental results in terms of metal flow stress. Both the FE simulated and experimental results indicate that forming temperature and grain size have a significant influence on the accuracy of the produced product shape and metal flow behaviour in microforming due to the inhomogeneity within the deformed material. The mechanical behaviour of the material is found to be more sensitive to forming temperature when the workpieces are constituted of fine grains.
Karimi, M, Croaker, P & Kessissoglou, N 2017, 'Acoustic scattering for 3D multi-directional periodic structures using the boundary element method', The Journal of the Acoustical Society of America, vol. 141, no. 1, pp. 313-323.
View/Download from: Publisher's site
View description>>
An efficient boundary element formulation is proposed to solve three-dimensional exterior acoustic scattering problems with multi-directional periodicity. The multi-directional periodic acoustic problem is represented as a multilevel block Toeplitz matrix. By exploiting the Toeplitz structure, the computational time and storage requirements to construct and to solve the linear system of equations arising from the boundary element formulation are significantly reduced. The generalized minimal residual method is implemented to solve the linear system of equations. To efficiently calculate the matrix-vector product in the iterative algorithm, the original matrix is embedded into a multilevel block circulant matrix. A multi-dimensional discrete Fourier transform is then employed to accelerate the matrix-vector product. The proposed approach is applicable to a periodic acoustic problem for any arbitrary shape of the structure in both full space and half space. Two case studies involving sonic crystal barriers are presented. In the first case study, a sonic crystal barrier comprising rigid cylindrical scatterers is modeled. To demonstrate the effectiveness of the proposed technique, periodicity in one, two, or three directions is examined. In the second case study, the acoustic performance of a sonic crystal barrier with locally resonant C-shaped scatterers is studied.
Karimi, M, Croaker, P, Kinns, R & Kessissoglou, N 2017, 'Effect of a serrated trailing edge on sound radiation from nearby quadrupoles', The Journal of the Acoustical Society of America, vol. 141, no. 5, pp. 2997-3010.
View/Download from: Publisher's site
View description>>
A periodic boundary element technique is implemented to study the noise reduction capability of a plate with a serrated trailing edge under quadrupole excitation. It is assumed for this purpose that the quadrupole source tensor is independent of the trailing edge configuration and that the effect of the trailing edge shape is to modify sound radiation from prescribed boundary layer sources. The flat plate is modelled as a continuous structure with a finite repetition of small spanwise segments. The matrix equation formulated by the periodic boundary element method for this 3D acoustic scattering problem is represented as a block Toeplitz matrix. The discrete Fourier transform is employed in an iterative algorithm to solve the block Toeplitz system. The noise reduction mechanism for a serrated trailing edge in the near field is investigated by comparing contour plots obtained from each component of the quadrupole for unserrated and serrated trailing edge plate models. The noise reduction due to the serrated trailing edge is also examined as a function of the source location.
Karimi, M, Croaker, P, Peake, N & Kessissoglou, N 2017, 'Acoustic Scattering for Rotational and Translational Symmetric Structures in Nonuniform Potential Flow', AIAA Journal, vol. 55, no. 10, pp. 3318-3327.
View/Download from: Publisher's site
Kuruneru, STW, Sauret, E, Saha, SC & Gu, YT 2017, 'A coupled finite volume & discrete element method to examine particulate foulant transport in metal foam heat exchangers', International Journal of Heat and Mass Transfer, vol. 115, pp. 43-61.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd The exorbitant costs associated with particulate fouling necessitates the need to formulate advanced methods to comprehend mass transport and fouling in heat exchangers. A coupled finite volume and discrete element method is developed to investigate the mechanisms that govern particle-laden gas flows and particulate fouling in idealized porous metal foam heat exchangers. This meticulous examination will take great precedence in addressing the negative impact particulate fouling has in the industry. The numerical method will permit engineers to better optimize porous metal foams for applications such as air-cooled heat aluminium heat exchangers. The robustness of this numerical method is validated against the original and modified Darcy-Forchheimer analytical equations through a novel modified porosity theory. Good agreement is obtained between the numerical and analytical results. It is shown that both 2D and 3D heat exchanger configurations of identical porosities with different geometric profiles have shown similar deposition fraction and pressure drop magnitudes albeit having a slightly different fouling layer distribution. This is attributable to the particle properties and the variation between the 2D and 3D inlet injection plane surface area. It is found that the commencement of sandstone and sawdust deposition in a 6-pore configuration differs by 0.57 s, whereas a three pore configuration completely nullifies particulate fouling irrespective of foulant type. A staggered row configuration has shown significant reduction in pressure drop as compared to the 6-pore heat exchanger configuration. For the case of sandstone particles, the optimum heat exchanger geometry exhibits 78% less pressure drop and 100% less deposition fraction compared with the original 6-pore configuration.
Kuruneru, STW, Sauret, E, Saha, SC & Gu, YT 2017, 'Two- and four-way coupling of cohesive poly-disperse particulate foulants on a metal foam fibre immersed in quiescent fluid', International Communications in Heat and Mass Transfer, vol. 89, pp. 176-184.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd The ubiquity and complexity of the unsteadiness of fouling and multiphase flows in various engineering systems signify the need to develop advanced numerical methods to study the underlying phenomena of two-phase particle-laden fluid flows in heat exchanger systems such as, compact electronics cooling (i.e. heat sinks) and HVAC & R systems. Fouling is omnipresent in many industries such as power generation, chemical, petroleum, among others. The mechanisms governing fouling coupled with multiphase foulant-laden fluid flow in porous heat exchangers, such as metal foams, are very complex and poorly understood. This investigation forms the basis for addressing the implications of fouling for a myriad of industrial processes. This study will discuss the development of a coupled finite volume method and discrete element method (FVM-DEM) numerical framework to investigate the mechanisms governing particulate fouling in an idealized metal foam heat exchanger. This study resolves four-way and two-way coupled interactions based on poly-disperse cohesive foulants in fluid-saturated foam. The significance stems from the inclusion of cohesiveness between particle-particle and particle-wall contacts which play a decisive role in the foulant aggregation process prevalent in particles with a diameter smaller than 50 μm. The present results show that the cohesive foulants exhibit strong tendency to aggregate with time and form chain-like projections. A rigid aggregate stack is formed which alters the fluid velocity of the fluid-filled foam. Quantitative analysis of the foulant count and time-averaged aggregate count is discussed. The presented results and the numerical framework could potentially be used to optimize heat exchanger designs by considering operating conditions and foam morphology (i.e. pore diameter, ligament thickness, porosity) that is most susceptible to particulate fouling.
Kuruneru, STW, Sauret, E, Vafai, K, Saha, SC & Gu, Y 2017, 'Analysis of particle-laden fluid flows, tortuosity and particle-fluid behaviour in metal foam heat exchangers', Chemical Engineering Science, vol. 172, pp. 677-687.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Tortuosity and porosity are critical parameters for characterizing fluid flow in porous media. These parameters are of paramount importance in the design of porous compact heat exchangers, packed bed reactors, and catalysis supports; however, in the context of heat exchangers, these parameters are generally formulated for single-phase fluid flow under steady-state conditions. However, most industrial flows in a porous medium such as metal foams comprise of transient particle-laden fluid flow. A coupled finite volume and discrete element method (FVM-DEM) is developed to examine transient particle-laden Stokesian flow, particulate fouling (deposition), and fluid flow patterns in an idealized porous metal foam. This work presents a comparative analysis of the analytical and numerical pressure drop profiles. The solid-gas suspension in a porous media is discussed. Secondly, a new time-dependent pore-level fluid tortuosity relation is established which is linked with a modified porosity-based Darcy-Forchheimer equation. Fluid disturbance attributable to the inception of particle deposition is quantified by the tortuosity and instantaneous shift in streamline angle ratio. It is shown that the streamline angle ratio and the meandering of fluid flow paths vary with changing porosity and tortuosity. Moreover, the Reynolds number and particle density play a critical role in the alteration of the resistance to fluid flow and permeability which is related to the tortuosity and variation in fluid flow behaviour. The results and numerical method serves as a steppingstone to better optimize various heat exchangers while taking into account complex multiphase flow behaviour and the tortuous flow paths of porous structures.
Lemmerz, K, Glogowski, P, Arenbeck, H, Barthelmey, A, Strothotte, L, Hypki, A, Kuhlenkötter, B & Deuse, J 2017, 'Collaborative assembly system', Productivity Management, vol. 22, no. 4, pp. 13-15.
View description>>
The design of assembly systems with human-robot collaboration (HRC) is a complex task due to the variety of goal criteria that have to be considered. A digital tool for designing and securing HRC-applications as well as adequate training and qualification concepts for companies are yet missing and are still major obstacles to the use of HRC. This paper proposes a new methodology for the task-based digital design of collaborative assembly systems. In the future, this will ensure that companies are getting empowered for a straightforward development and commissioning of HRC-systems.
Leurent, M, Jasserand, F, Locatelli, G, Palm, J, Rämä, M & Trianni, A 2017, 'Driving forces and obstacles to nuclear cogeneration in Europe: Lessons learnt from Finland', Energy Policy, vol. 107, pp. 138-150.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Nuclear power plants generate electricity and a large amount of waste heat which is valuable for cogeneration. District heating (DH) is a suitable technology to decarbonize the European heat sector. By contrast with most of nuclear non-electric applications, nuclear district heating (NDH) has already been implemented in Europe, thus providing us with some valuable empirical insights. This paper investigates the forces and obstacles to nuclear cogeneration by looking at the Loviisa 3 NDH project in Finland. The key forces are energy efficiency, decarbonization of the heat sector, operational competitiveness of future nuclear technologies, and synergies with renewable energies. The key obstacles are split incentives, electricity prices volatility, inexpediency of business models and regulatory frameworks, electioneering of local authorities and pessimist expectations with regards to project financing. Policy makers should recognize nuclear plants alongside other utilities generating large amounts of wasted heat. International cooperation programs involving both nuclear and heat stakeholders should be encouraged. EU28 Member States wanting to promote nuclear cogeneration may consider providing support for the electricity generated by high-efficiency plants.
Li, Q, Xiong, R & Vidal-Calleja, T 2017, 'A GMM based uncertainty model for point clouds registration', Robotics and Autonomous Systems, vol. 91, pp. 349-362.
View/Download from: Publisher's site
View description>>
© 2016 Elsevier B.V. The existing methods for the registration of point clouds acquired by laser scanners have some limitations. Firstly, as some samples of surface, a point cloud acquired by the laser scanner, which normally works in a spherical fashion, has very limited density when the surface is far away from the laser scanner and the density varies a lot at different ranges. Current registration methods cannot accurately model the surface uncertainty for such kind of point clouds of limited and large varying density. Secondly, when the point cloud is acquired while the platform is simultaneously moving, the estimation error of the platform motion makes the acquired point cloud distorted. To deal with these problems, in this paper, we propose an uncertainty model based on the Gaussian Mixture Model (GMM) to represent the point cloud. Specifically, we construct the GMM piece-wisely on the underlying surface of point cloud, which will accurately model the surface uncertainty. Also a hierarchical structure is employed to increase the robustness of the registration. Furthermore, by assigning each Gaussian component with a pose, a probabilistic graph can be constructed to tackle the problem of registration when the platform is moving while scanning. In this way the distorted point cloud, caused by the estimation error of the platform's motion, can be corrected by performing graph optimization. Simulation and real world experimental results show that our method leads to better convergence than the state-of-the-art methods due to the accurate modeling of the surface uncertainty and the hierarchical structure, and it also enables us to correct the distorted point clouds.
Liao, Y, Kodagoda, S, Wang, Y, Shi, L & Liu, Y 2017, 'Place Classification With a Graph Regularized Deep Neural Network', IEEE Transactions on Cognitive and Developmental Systems, vol. 9, no. 4, pp. 304-315.
View/Download from: Publisher's site
Liu, J, Miao, Z, Ji, J & Zhou, J 2017, 'Group Regional Consensus of Networked Lagrangian Systems With Input Disturbances', Journal of Dynamic Systems, Measurement, and Control, vol. 139, no. 9.
View/Download from: Publisher's site
View description>>
Networked multirobot systems under the coordinated control can perform tasks more effectively than a group of individually operating robots. This paper studies the group regional consensus of networked multirobot systems (formulated by second-order Lagrangian dynamics) having input disturbances under directed acyclic topology. An adaptive control protocol is designed to achieve group regional consensus of the networked Lagrangian systems with parametric uncertainties for both leader and leaderless cases. Sufficient conditions are established to guarantee group regional consensus for any prior given desired consensus errors. Compared with the existing work, a distinctive feature of the proposed control algorithm is that the stability analysis indicates the global validity of the obtained consensus results. Numerical examples are provided to demonstrate the effectiveness of the proposed scheme.
Luo, L, Jiang, Z & Wei, D 2017, 'Influences of micro-friction on surface finish in micro deep drawing of SUS304 cups', Wear, vol. 374-375, pp. 36-45.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier B.V. Surface asperities take a large part of a thin blank in micro-sheet forming processes. Contact and friction significantly affect micro-sheet forming and cannot be simplified as homogeneous in simulation. Material heterogeneity of the blank further affects the friction and its impact becomes significant in micro-scale. In this study, a FE model representing surface morphology of SUS304 sheets was built for micro deep drawing simulation. Each node on the blank model had the same height as an asperity. Key surface morphological characters of the blank can be presented with a proper mesh density. The material size effects were presented via refined material properties assignment based on sheets’ microstructures. Due to the initial surface morphology, wear accumulation and thickness distribution were significantly affected. Experimental results well validated prediction of worst worn area on drawn cup mouth in simulation. Surface roughening which affects shape accuracy in the micro-scale was affected by the wear behaviour during the drawing process. Thus, different roughening behaviours at three divided areas on the drawn cup were wall explained.
Luo, L, Jiang, Z & Wei, D 2017, 'Reprint of ‘‘Influences of micro-friction on surface finish in micro deep drawing of SUS304 cups’’', Wear, vol. 376-377, pp. 1147-1155.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier B.V. Surface asperities take a large part of a thin blank in micro-sheet forming processes. Contact and friction significantly affect micro-sheet forming and cannot be simplified as homogeneous in simulation. Material heterogeneity of the blank further affects the friction and its impact becomes significant in micro-scale. In this study, a FE model representing surface morphology of SUS304 sheets was built for micro deep drawing simulation. Each node on the blank model had the same height as an asperity. Key surface morphological characters of the blank can be presented with a proper mesh density. The material size effects were presented via refined material properties assignment based on sheets' microstructures. Due to the initial surface morphology, wear accumulation and thickness distribution were significantly affected. Experimental results well validated prediction of worst worn area on drawn cup mouth in simulation. Surface roughening which affects shape accuracy in the micro-scale was affected by the wear behaviour during the drawing process. Thus, different roughening behaviours at three divided areas on the drawn cup were wall explained.
Luo, L, Jiang, ZY, Wei, DB, Sato, H, Furushima, T & Manabe, K 2017, 'Effects of Hydraulic Pressure on Shape Accuracy of Drawn Circular Cups during Micro Hydro Deep Drawing', Materials Science Forum, vol. 879, pp. 2274-2279.
View/Download from: Publisher's site
View description>>
Micro hydro deep drawing is a promising technology to fabricate micro metal products with complex 3D shapes. However, the size effects in the micro hydro deep drawing become considerable and significantly influence shape accuracy of drawn cups. In this study, a Voronoi micro scale simulation model was developed to consider the size effects of SUS304 foils. A surface layer model was additionally applied in the simulation to further explain the size effects. The micro hydro deep drawing experiments were conducted with annealed SUS304 foils and the drawn cups were examined. The wrinkling phenomenon was generally aggravated with the hydraulic pressure. Simulation results also show that the high hydraulic pressure does not improve the shape accuracy of the drawn cups as that in the normal scale hydro deep dawning process does. The simulation results are in accordance with the experimental results.
Luo, L, Wei, D, Jiang, Z, Zhou, C, Huang, Q & Huang, Z 2017, 'Study of micro hydromechanical deep drawing of SUS304 circular cups by an ALE model', Procedia Engineering, vol. 207, pp. 1039-1044.
View/Download from: Publisher's site
View description>>
© 2017 The Authors. Published by Elsevier Ltd. Accurate estimation of hydraulic pressure on the blank is important for micro hydromechanical deep drawing simulation. An Arbitrary Lagrange Eulerian (ALE) simulation model that considers strong fluid-solid interaction (FSI) was generated to accurately predict the hydraulic pressure on the blank. The changeable pressure significantly affects the drawn cup's quality regarding wall thickness. Both the minimum and the maximum wall thicknesses in the ALE model are significantly different from that in a conventional model with a simple pressure load. The relationship between the maximum thickness and the hydraulic pressure in the ALE model is similar to that from the experimental results while reverse to that from the conventional simulation model. The ALE model provides more precise hydraulic pressure on the blank and accurate prediction of the drawn cups' quality compared with the conventional model.
Luo, L, Wei, D, Wang, X, Zhou, C, Huang, Q, Xu, J, Wu, D & Jiang, Z 2017, 'Effects of hydraulic pressure on wrinkling and earing in micro hydro deep drawing of SUS304 circular cups', The International Journal of Advanced Manufacturing Technology, vol. 90, no. 1-4, pp. 189-197.
View/Download from: Publisher's site
View description>>
© 2016, Springer-Verlag London. Influences of hydraulic pressure on forming features in micro hydro deep drawing are different from those in normal drawing due to the small size of specimens. In this study, micro hydro deep drawing of SUS304 sheets was carried out in order to study the impacts of the hydraulic pressure on the quality of the drawn cup. Experimental results indicate that there is a critical hydraulic pressure range from 3 to 6 % of the blank’s initial yield stress, where wrinkling and earing development trends change twice. The wrinkling and the earing of the drawn cup also reach their local extremes in the critical pressure range. The cup earing value moves in the opposite direction from the wrinkling value. Hydraulic pressure affects the wrinkling and the earing of the drawn cup through changes in the micro-frictional condition, the shape of the blank and its strain-stress state. Micro-finite element (FE) simulation which takes these factors as well as the material size effects into consideration showed similar results to the experimental ones, thus validating the experimental results and the suitability of the micro-simulation model for micro-forming FE simulation. The experimental and simulation results indicate that the critical hydraulic pressure based on the blank’s initial yield stress can restrict the wrinkling and the earing of the drawn cup. Ultra-high pressure has the potential to avoid the cup wrinkling and earing.
Luo, Q & Tong, L 2017, 'A deformation mechanism based material model for topology optimization of laminated composite plates and shells', Composite Structures, vol. 159, pp. 246-256.
View/Download from: Publisher's site
Ma, J, Xu, F & Saha, SC 2017, 'Flows and heat transfer of the transition to an unsteady state in a finned cavity for different Prandtl numbers', International Communications in Heat and Mass Transfer, vol. 88, pp. 220-227.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Flows and heat transfer of the transition to an unsteady state in a finned cavity are studied for Prandtl numbers (Pr) from 0.1 to 100 and Rayleigh numbers (Ra) from 10 7 to 10 10 . Transient flows are described in the finned cavity. Critical Rayleigh numbers of the transition to an unsteady state are obtained for different Prandtl numbers and the relation between two dimensionless parameters is given. The spectral analysis is applied for the oscillations of unsteady flows and the dominant frequency dependent on governing parameters is presented. Heat transfer of the transition to an unsteady flow is quantified and the corresponding relations dependent on the Prandtl number and Rayleigh number are gained. It is demonstrated that the flow rate and the Nusselt number of the finned cavity significantly increase due to the presentence of the fin, which depend on the Prandtl number and the Rayleigh number.
Ma, Y, Saha, S, Miller, W & Guan, L 2017, 'Comparison of Different Solar-Assisted Air Conditioning Systems for Australian Office Buildings', Energies, vol. 10, no. 10, pp. 1463-1463.
View/Download from: Publisher's site
View description>>
© 2017 by the authors. This study has investigated the feasibility of three different solar-assisted air conditioning systems for typical medium-sized office buildings in all eight Australian capital cities using the whole building energy simulation software EnergyPlus. The studied solar cooling systems include: solar desiccant-evaporative cooling (SDEC) system, hybrid solar desiccant-compression cooling (SDCC) system, and solar absorption cooling (SAC) system. A referenced conventional vapor compression variable-air-volume (VAV) system has also been investigated for comparison purpose. The technical, environmental, and economic performances of each solar cooling system have been evaluated in terms of solar fraction (SF), system coefficient of performance (COP), annual HVAC (heating, ventilation, and air conditioning) electricity consumption, annual CO2 emissions reduction, payback period (PBP), and net present value (NPV). The results demonstrate that the SDEC system consumes the least energy in Brisbane and Darwin, achieving 56.9% and 82.1% annual energy savings, respectively, compared to the conventional VAV system, while for the other six cities, the SAC system is the most energy efficient. However, from both energy and economic aspects, the SDEC system is more feasible in Adelaide, Brisbane, Darwin, Melbourne, Perth, and Sydney because of high annual SF and COP, low yearly energy consumption, short PBP and positive NPV, while for Canberra and Hobart, although the SAC system achieves considerable energy savings, it is not economically beneficial due to high initial cost. Therefore, the SDEC system is the most economically beneficial for most of Australian cities, especially in hot and humid climates. The SAC system is also energy efficient, but is not as economic as the SDEC system. However, for Canberra and Hobart, reducing initial cost is the key point to achieve economic feasibility of solar cooling applications.
Ma, Y, Saha, SC, Miller, W & Guan, L 2017, 'Parametric Analysis of Design Parameter Effects on the Performance of a Solar Desiccant Evaporative Cooling System in Brisbane, Australia', Energies, vol. 10, no. 7, pp. 849-849.
View/Download from: Publisher's site
View description>>
© 2017 by the authors. Solar desiccant cooling is widely considered as an attractive replacement for conventional vapor compression air conditioning systems because of its environmental friendliness and energy efficiency advantages. The system performance of solar desiccant cooling strongly depends on the input parameters associated with the system components, such as the solar collector, storage tank and backup heater, etc. In order to understand the implications of different design parameters on the system performance, this study has conducted a parametric analysis on the solar collector area, storage tank volume, and backup heater capacity of a solid solar desiccant cooling system for an office building in Brisbane, Australia climate. In addition, a parametric analysis on the outdoor air humidity ratio control set-point which triggers the operation of the desiccant wheel has also been investigated. The simulation results have shown that either increasing the storage tank volume or increasing solar collector area would result in both increased solar fraction (SF) and system coefficient of performance (COP), while at the same time reduce the backup heater energy consumption. However, the storage tank volume is more sensitive to the system performance than the collector area. From the economic aspect, a storage capacity of 30 m3/576 m2 has the lowest life cycle cost (LCC) of 405,954 for the solar subsystem. In addition, 100 kW backup heater capacity is preferable for the satisfaction of the design regeneration heating coil hot water inlet temperature set-point with relatively low backup heater energy consumption. Moreover, an outdoor air humidity ratio control set-point of 0.008 kgWater/kgDryAir is more reasonable, as it could both guarantee the indoor design conditions and achieve low backup heater energy consumption.
McPhee, MJ, Walmsley, BJ, Skinner, B, Littler, B, Siddell, JP, Cafe, LM, Wilkins, JF, Oddy, VH & Alempijevic, A 2017, 'Live animal assessments of rump fat and muscle score in Angus cows and steers using 3-dimensional imaging1', Journal of Animal Science, vol. 95, no. 4, pp. 1847-1857.
View/Download from: Publisher's site
View description>>
© 2017 American Society of Animal Science. All rights reserved. The objective of this study was to develop a proof of concept for using off-the-shelf Red Green Blue-Depth (RGB-D) Microsoft Kinect cameras to objectively assess P8 rump fat (P8 fat; mm) and muscle score (MS) traits in Angus cows and steers. Data from low and high muscled cattle (156 cows and 79 steers) were collected at multiple locations and time points. The following steps were required for the 3-dimensional (3D) image data and subsequent machine learning techniques to learn the traits: 1) reduce the high dimensionality of the point cloud data by extracting features from the input signals to produce a compact and representative feature vector, 2) perform global optimization of the signatures using machine learning algorithms and a parallel genetic algorithm, and 3) train a sensor model using regression-supervised learning techniques on the ultrasound P8 fat and the classified learning techniques for the assessed MS for each animal in the data set. The correlation of estimating hip height (cm) between visually measured and assessed 3D data from RGB-D cameras on cows and steers was 0.75 and 0.90, respectively. The supervised machine learning and global optimization approach correctly classified MS (mean [SD]) 80 (4.7) and 83% [6.6%] for cows and steers, respectively. Kappa tests of MS were 0.74 and 0.79 in cows and steers, respectively, indicating substantial agreement between visual assessment and the learning approaches of RGB-D camera images. A stratified 10-fold cross-validation for P8 fat did not find any differences in the mean bias (P = 0.62 and P = 0.42 for cows and steers, respectively). The root mean square error of P8 fat was 1.54 and 1.00 mm for cows and steers, respectively. Additional data is required to strengthen the capacity of machine learning to estimate measured P8 fat and assessed MS. Data sets for Bos indicus and continental cattle are also required to broaden the use...
Montiel, F, Chung, H, Karimi, M & Kessissoglou, N 2017, 'An analytical and numerical investigation of acoustic attenuation by a finite sonic crystal', Wave Motion, vol. 70, pp. 135-151.
View/Download from: Publisher's site
View description>>
Sonic crystals are scatterers arranged periodically in a homogeneous fluid medium, for which sound does not transmit through the crystal in certain frequency bands known as stop bands. Acoustic wave transmission through a two-dimensional sonic crystal composed of a finite array of scatterers is investigated. Two types of scatterers are considered: sound-hard cylinders and C-shaped locally resonant scatterers. An analytical method is devised to solve the corresponding multiple scattering problems. The method combines an integral equation technique for the single scatterer with an enhanced multipole method using domain decomposition into slabs. A numerical approach using commercial software is also considered for validation and is based on the finite element method. Simulations of sound transmission through an array of 5 by 51 scatterers show remarkably good agreement with the corresponding infinite system. For an array comprising locally resonant scatterers, an approximate band gap around the resonator natural frequency is observed in addition to the band gap due to the overall periodicity of the finite sonic crystal.
Nguyen, LV, Kodagoda, S, Ranasinghe, R & Dissanayake, G 2017, 'Adaptive Placement for Mobile Sensors in Spatial Prediction Under Locational Errors', IEEE Sensors Journal, vol. 17, no. 3, pp. 794-802.
View/Download from: Publisher's site
View description>>
This paper addresses the problem of driving robotic sensors for an energy-constrained mobile wireless network in efficiently monitoring and predicting spatial phenomena, under data locational errors. The paper first discusses how errors of mobile sensor locations affect estimating and predicting the spatial physical processes, given that spatial field to be monitored is modeled by a Gaussian process. It then proposes an optimality criterion for designing optimal sampling paths for the mobile robotic sensors given the localization uncertainties. Although the optimization problem is optimally intractable, it can be resolved by a polynomial approximation algorithm, which is proved to be practically feasible in an energy-constrained mobile sensor network. More importantly, near-optimal solutions of this navigation problem are guaranteed by a lower bound within 1-(1/e) of the optimum. The performance of the proposed approach is evaluated on simulated and real-world data sets, where impact of sensor location errors on the results is demonstrated by comparing the results with those obtained by using noise-less data locations.
Niktash, A & Huynh, BP 2017, 'ICCM2015: A Comparison of RANS and LES Computational Methods in Analyzing Ventilation Flow Through a Room Fitted with a Two-Sided Windcatcher', International Journal of Computational Methods, vol. 14, no. 03, pp. 1750021-1750021.
View/Download from: Publisher's site
View description>>
A windcatcher is a structure for providing natural ventilation using wind power; it is usually fitted on the roof of a building to exhaust the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building. In this paper, the behavior of free wind flow through a three-dimensional room fitted with a centered position two-canal bottom shape windcatcher model is investigated numerically, using a commercial computational fluid dynamics (CFD) software package and LES (Large Eddy Simulation) CFD method. The results have been compared with the obtained results for the same model but using RANS (Reynolds Averaged Navier–Stokes) CFD method. The model with its surrounded space has been considered in both method. It is found that the achieved results for the model from LES method are in good agreement with RANS method’s results for the same model.
Nobbs, M & Blamires, SJ 2017, 'Fiddler crab spatial distributions are influenced by physiological stressors independent of sympatric interactions', Journal of Experimental Marine Biology and Ecology, vol. 491, pp. 19-26.
View/Download from: Publisher's site
Norouzi, M, Miro, JV & Dissanayake, G 2017, 'Planning Stable and Efficient Paths for Reconfigurable Robots On Uneven Terrain', Journal of Intelligent & Robotic Systems, vol. 87, no. 2, pp. 291-312.
View/Download from: Publisher's site
View description>>
© 2017, Springer Science+Business Media Dordrecht. An analytical strategy to generate stable paths for reconfigurable mobile robots such as those equipped with manipulator arms and/or flippers, operating in an uneven environment whilst also meeting additional navigational objectives is hereby proposed. The suggested solution looks at minimising the length of the traversed path and the energy expenditure in changing postures, and also accounts for additional constraints in terms of sensor visibility and traction. This is particularly applicable to operations such as search and rescue where observing the environment for locating victims is the major objective, although this technique can be generalised to incorporate other potentially conflicting objectives (e.g. maximising ground clearance for a legged robot). The validity of the proposed approach is evaluated with two popular graph-based planners (A* and RRT) on a multi-tracked robot fitted with a manipulator arm and a range camera. Two challenging 3D terrain data sets have been employed: one obtained whilst operating the robot in a mock-up urban search and rescue (USAR) arena, and a second one, a reference on-line data set acquired on the quasi-outdoor rover testing facility at the University of Toronto Institute for Aerospace Studies (UTIAS).
Oberst, S, Bann, G, Lai, JCS & Evans, TA 2017, 'Cryptic termites avoid predatory ants by eavesdropping on vibrational cues from their footsteps', Ecology Letters, vol. 20, no. 2, pp. 212-221.
View/Download from: Publisher's site
View description>>
AbstractEavesdropping has evolved in many predator–prey relationships. Communication signals of social species may be particularly vulnerable to eavesdropping, such as pheromones produced by ants, which are predators of termites. Termites communicate mostly by way of substrate‐borne vibrations, which suggest they may be able to eavesdrop, using two possible mechanisms: ant chemicals or ant vibrations. We observed termites foraging within millimetres of ants in the field, suggesting the evolution of specialised detection behaviours. We found the termite Coptotermes acinaciformis detected their major predator, the ant Iridomyrmex purpureus, through thin wood using only vibrational cues from walking, and not chemical signals. Comparison of 16 termite and ant species found the ants‐walking signals were up to 100 times higher than those of termites. Eavesdropping on passive walking signals explains the predator detection and foraging behaviours in this ancient relationship, which may be applicable to many other predator–prey relationships.
Oberst, S, Marburg, S & Hoffmann, N 2017, 'Determining periodic orbits via nonlinear filtering and recurrence spectra in the presence of noise', Procedia Engineering, vol. 199, pp. 772-777.
View/Download from: Publisher's site
Pagano, D & Liu, D 2017, 'An approach for real-time motion planning of an inchworm robot in complex steel bridge environments', Robotica, vol. 35, no. 6, pp. 1280-1309.
View/Download from: Publisher's site
View description>>
SUMMARYPath planning can be difficult and time consuming for inchworm robots especially when operating in complex 3D environments such as steel bridges. Confined areas may prevent a robot from extensively searching the environment by limiting its mobility. An approach for real-time path planning is presented. This approach first uses the concept of line-of-sight (LoS) to find waypoints from the start pose to the end node. It then plans smooth, collision-free motion for a robot to move between waypoints using a 3D-F2algorithm. Extensive simulations and experiments are conducted in 2D and 3D scenarios to verify the approach.
Peng, X-F, Liu, J, Han, J-T & Wei, D-B 2017, 'Effect of hot/warm roll-forming process on microstructural evolution and mechanical properties of local thickened U-rib for orthotropic steel deck', Journal of Iron and Steel Research International, vol. 24, no. 3, pp. 335-342.
View/Download from: Publisher's site
View description>>
© 2017 Central Iron and Steel Research Institute To improve the strength-toughness of traditional U-rib (TUR) and solve the problem of insufficient penetration between TUR and deckplate, a new local thickened U-rib (LTUR) has been proposed to improve the fatigue resistance of the weld joint under the premise of not increasing thickness and strength of the TUR material. And a hot/warm roll-forming process (RFP) adopting partially induction heating to 700—1000 °C was carried out to fabricate LTUR. The deformation behaviors in the forming process and microstructure of LTUR have been investigated. Mechanical properties and fracture mechanism of the LTUR after hot/warm RFP have been systematically discussed. Moreover, the results are compared with those obtained in cold RFP. Mechanical properties of the LTUR deformed above the critical transformation temperature (A c3) show high performance characteristics with marked fatigue resistance and superior toughness. Upon increasing the heating temperature from 700 to 900 °C, the initial coarse ferrite-pearlite structure transform into equiaxed ultrafine ferrite (1—3 μm) and precipitates such as (Nb, Ti)(C, N) are uniformly distributed in the matrix. The average dislocation density of the specimens after hot roll-forming at heating temperature of 900 °C decreases dramatically compared with those of the specimens subjected to the cold RFP. Furthermore, a typical characteristic of ductile fracture mechanism and the high impact energy are more convinced that the specimens deformed above 900 °C have obtained an optimal combination of strength and toughness.
Qiao, M, Xu, F & Saha, SC 2017, 'Scaling analysis and numerical simulation of natural convection from a duct', Numerical Heat Transfer, Part A: Applications, vol. 72, no. 5, pp. 355-371.
View/Download from: Publisher's site
Qu, F, Jiang, Z, Wei, D, Chen, Q & Lu, H 2017, 'Study of micro flexible rolling based on grained inhomogeneity', International Journal of Mechanical Sciences, vol. 123, pp. 324-339.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd This paper shows an analytical, numerical and experimental investigation to comprehend the role of grained inhomogeneity which plays in micro flexible rolling in terms of the average rolling force and the thickness directional springback of the workpiece after it exits the roll bite zone. Miniature tensile tests and micro hardness tests are accomplished to identify the scattered stress-strain curves for 500 μm thick aluminium alloy 1060 samples with grain size of approximately 23-71 µm and to determine the weighted heterogeneity coefficient for each sample separately, according to which the theoretical calculations and numerical simulations based upon 3D Voronoi tessellation technique have been performed under actual experimental conditions where reductions of 25 to 50 % are selected. The scattering effect associated with the anisotropic nature of single grains has been perceived in the micro flexible rolling process and both the analytical and finite element models developed have been validated via experimental data to hold promise for predicting the rolling force and the thickness directional springback of the workpiece, as well as boosting the thickness profile control performance of the micro flexible rolling mill.
Quin, P, Paul, G & Liu, D 2017, 'Experimental Evaluation of Nearest Neighbor Exploration Approach in Field Environments.', IEEE Trans Autom. Sci. Eng., vol. 14, no. 2, pp. 869-880.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Inspecting surface conditions in 3-D environments such as steel bridges is a complex, time-consuming, and often hazardous undertaking that is an essential part of tasks such as bridge maintenance. Developing an autonomous exploration strategy for a mobile climbing robot would allow for such tasks to be completed more quickly and more safely than is possible with human inspectors. The exploration strategy tested in this paper, called the nearest neighbors exploration approach (NNEA), aims to reduce the overall exploration time by reducing the number of sensor position evaluations that need to be performed. NNEA achieves this by first considering at each time step only a small set of poses near to the current robot as candidates for the next best view. This approach is compared with another exploration strategy for similar robots performing the same task. The improvements between the new and previous strategy are demonstrated through trials on a test rig, and also in field trials on a ferromagnetic bridge structure. Note to Practitioners-This paper was motivated by the problem of inspecting confined spaces for rust and flaking paint with a manipulator robot arm. Existing approaches involve creating a large set of candidate robot poses to take a scan from. Evaluating all these candidate poses is very time consuming if full coverage is guaranteed. This paper suggests a principled method for restricting the size of this set in a way that does not reduce inspection coverage but decreases overall time taken for inspection.
Riis, JO, Achenbach, M, Israelsen, P, Kyvsgaard Hansen, P, Johansen, J & Deuse, J 2017, 'Dealing with complex and ill-structured problems: results of a Plan-Do-Check-Act experiment in a business engineering semester', European Journal of Engineering Education, vol. 42, no. 4, pp. 396-412.
View/Download from: Publisher's site
View description>>
© 2016 SEFI. Challenged by increased globalisation and fast technological development, we carried out an experiment in the third semester of a global business engineering programme aimed at identifying conditions for training student in dealing with complex and ill-structured problems of forming a new business. As this includes a fuzzy front end, learning cannot be measured in traditional, quantitative terms; therefore, we have explored the use of reflection to convert tacit knowledge to explicit knowledge. The experiment adopted a Plan-Do-Check-Act approach and concluded with developing a plan for new learning initiatives in the subsequent year’s semester. The findings conclude that (1) problem-based learning develops more competencies than ordinarily measured at the examination, especially, the social/communication and personal competencies are developed; (2) students are capable of dealing with a complex and ambiguous problem, if properly guided. Four conditions were identified; (3) most students are not conscious of their learning, but are able to reflect if properly encouraged; and (4) improving engineering education should be considered as an organisational learning process.
Rothberg, SJ, Allen, MS, Castellini, P, Di Maio, D, Dirckx, JJJ, Ewins, DJ, Halkon, BJ, Muyshondt, P, Paone, N, Ryan, T, Steger, H, Tomasini, EP, Vanlanduit, S & Vignola, JF 2017, 'An international review of laser Doppler vibrometry: Making light work of vibration measurement', Optics and Lasers in Engineering, vol. 99, pp. 11-22.
View/Download from: Publisher's site
View description>>
© 2016 In 1964, just a few years after the invention of the laser, a fluid velocity measurement based on the frequency shift of scattered light was made and the laser Doppler technique was born. This comprehensive review paper charts advances in the development and applications of laser Doppler vibrometry (LDV) since those first pioneering experiments. Consideration is first given to the challenges that continue to be posed by laser speckle. Scanning LDV is introduced and its significant influence in the field of experimental modal analysis described. Applications in structural health monitoring and MEMS serve to demonstrate LDV's applicability on structures of all sizes. Rotor vibrations and hearing are explored as examples of the classic applications. Applications in acoustics recognise the versatility of LDV as demonstrated by visualisation of sound fields. The paper concludes with thoughts on future developments, using examples of new multi-component and multi-channel instruments.
Ruppert, MG & Yong, YK 2017, 'Note: Guaranteed collocated multimode control of an atomic force microscope cantilever using on-chip piezoelectric actuation and sensing', Review of Scientific Instruments, vol. 88, no. 8, pp. 086109-086109.
View/Download from: Publisher's site
View description>>
The quality (Q) factor is an important parameter of the resonance of the microcantilever as it determines both imaging bandwidth and force sensitivity. The ability to control the Q factor of multiple modes is believed to be of great benefit for atomic force microscopy techniques involving multiple eigenmodes. In this paper, we propose a novel cantilever design employing multiple piezoelectric transducers which are used for separated actuation and sensing, leading to guaranteed collocation of the first eight eigenmodes up to 3 MHz. The design minimizes the feedthrough usually observed with these systems by incorporating a guard trace on the cantilever chip. As a result, a multimode Q controller is demonstrated to be able to modify the quality factor of the first two eigenmodes over up to four orders of magnitude without sacrificing robust stability.
Ruppert, MG, Fowler, AG, Maroufi, M & Moheimani, SOR 2017, 'On-Chip Dynamic Mode Atomic Force Microscopy: A Silicon-on-Insulator MEMS Approach', Journal of Microelectromechanical Systems, vol. 26, no. 1, pp. 215-225.
View/Download from: Publisher's site
Ruppert, MG, Maroufi, M, Bazaei, A & Moheimani, SOR 2017, 'Kalman Filter Enabled High-Speed Control of a MEMS Nanopositioner', IFAC-PapersOnLine, vol. 50, no. 1, pp. 15554-15560.
View/Download from: Publisher's site
Sato, H, Manabe, K, Furushima, T, Wei, DB, Jiang, ZY & Alexandrov, S 2017, 'On the Scale Dependence of Micro Hydromechanical Deep Drawing', Key Engineering Materials, vol. 725, pp. 689-694.
View/Download from: Publisher's site
View description>>
Tooling feature size to minimum thickness becomes small in micro scale products and its ratio affects the deformation behavior in micro sheet forming significantly. In this study, the effect of this relative tooling feature size on drawing characteristics and effects to improve the drawability, such as friction holding effect, hydrodynamic lubrication effect and compression effect by blank edge radial pressure, in micro hydromechanical deep drawing (MHDD) are investigated using plasticity theory and numerical simulation. The results show that the micro drawing characteristics in MHDD can be improved by applying counter pressure. However, the required fluid pressures for friction holding and hydrodynamic lubrication effects increase as the relative punch diameter and/or die shoulder radius to thickness decrease, although the compression effect by radial pressure on the blank edge is independent of the relative tooling feature size.
Sefidan, AM, Sojoudi, A & Saha, SC 2017, 'Nanofluid-based cooling of cylindrical lithium-ion battery packs employing forced air flow', International Journal of Thermal Sciences, vol. 117, pp. 44-58.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Masson SAS Efficient cooling strategies are very important issues in thermal management of lithium-Ion battery system and these techniques should provide cost effective and energy saving solutions for temperature rise of the system during battery operation. A pseudo 2D electrochemical model has been used to investigate the electrochemical and thermal condition of commercial 18650 Lithium-Ion battery. This analysis was compared to previous experimental studies and results showed that the model predicts the temperature rise and thermal power generation very well. Results from the electro-thermal analysis were used to examine a cooling method. In this strategy, the cylindrical Li-ion cell is submersed within a thin cylindrical tank containing water-Al2O3 nanofluid. Air flow is employed to remove the heat from the system during discharge process. After testing this method for a single cell with various sizes of the secondary cylinder, critical and thermally dangerous arrangements of Li-ion cells were analyzed employing the new technique. 3D transient Computational Fluid Dynamics (CFD) simulations were used to see the effect of presence of the secondary cylinder on temperature rise. Results revealed that the new method reduces the maximum temperature of the cells efficiently.
Sefidan, AM, Sojoudi, A, Saha, SC & Cholette, M 2017, 'Multi-layer PCM solidification in a finned triplex tube considering natural convection', Applied Thermal Engineering, vol. 123, pp. 901-916.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Efficient latent heat storage systems represent an important opportunity to improve the thermal performance and operational capability of industrial systems (e.g. solar thermal). In this paper, numerical study is performed to evaluate the heat transfer and solidification features, phase change period and temperature distribution of double-layer Phase Changing Materials (PCM) in a finned triplex tube. A two-dimensional finite volume numerical technique is used to solve the governing equations considering conduction and convection heat transfer mechanisms at a fixed Rayleigh number of 106. After comparing the results for single and double layer configurations, possible arrangements of two different PCMs are discussed in terms of different thicknesses of each PCM, fin sizes and different heat transfer fluid temperatures. Results are illustrated as the form of temperature, liquid fraction, stream function and velocity magnitude contours and their changes over the freezing time. Variation of liquid fraction values, average and minimum temperatures of layers in a double-layer PCM are reported for better insight into the heat transfer features of the latent heat thermal energy storage system to enable uniform discharging designs and balance the phase changing rate within the whole annulus.
Siddiqui, AT, Arqam, M, Ahmad, H & Husain, S 2017, 'Rayleigh-Bénard Convection in Shear Enclosure: The Role of Thermal Instabilities', Materials Today: Proceedings, vol. 4, no. 9, pp. 9951-9955.
View/Download from: Publisher's site
Siedelhofer, C, Henke, T, Bellmann, A, Litterscheidt, J & Deuse, J 2017, 'Konzept zur Rekonfiguration flexibler Montagesysteme', Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 112, no. 3, pp. 141-145.
View/Download from: Publisher's site
View description>>
Kurzfassung Verkürzte Produktlebenszyklen und die Volatilität des Produktmixes resultieren im Montagebereich produzierender Unternehmen in hohem Aufwand durch Rekonfiguration. Es wird ein Rahmenmodell vorgestellt, welches die Effektivität der Rekonfiguration von Montagesystemen durch einen modularen, von Veränderungstreibern abhängigen Planungsprozess erhöht. Die Effizienz wird durch eine Planungsdatenbank gesteigert, welche die standardisierte Bereitstellung und Wiederverwendung von Planungsdaten ermöglicht.
Stone, BW, Harland, AR, Jones, JA, Mitchell, SR, Sherratt, PJ, Ranson, CA & Halkon, BJ 2017, 'On the dynamic response of an instrumented headform for alternative mounting stiffnesses when subjected to ballistic impacts', Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, vol. 231, no. 4, pp. 324-335.
View/Download from: Publisher's site
View description>>
© 2017, © IMechE 2017. The current British Standard for head protectors for cricketers has been recently revised to include a projectile-based battery of tests, the intention being to ensure that a certified helmet will also prevent contact of the ball or grille with the specified headform facial region. The purpose of this study was to characterise the dynamic response of the headform to direct ballistic impacts for alternative headform mounting arrangements. On one hand, and in accordance with the relevant sections of the Standard, what might be described as a ‘Constrained’ setup was evaluated while, on the other hand, an arrangement with significantly reduced stiffness, in line with that previously reported for the passive human neck, was subject to equivalent appraisal. For each mounting scenario, an air cannon was used to project a cricket training ball at three speeds towards the instrumented headform at three locations with five repeats per speed/location combination. High-rate/resolution video and piezoelectric accelerometer data were collected and processed to determine the headform response. While differences between specific ball impact speed and location scenarios are set out in detail later in the article, overall observations are summarised as follows. From a ball/headform contact duration standpoint, video derived results showed ranges of 1.30–1.45 ms (Constrained) versus 1.26–1.41 ms. Maximum ball deformations, the timing of which enabling the event to be subdivided into ‘loading’ and ‘unloading’ phases, were found to be 82.5%–86.2% (Constrained) versus 82.8%–86.4% of original ball diameter; mean peak headform accelerations during loading were found to be 860–1615 m/s2 (Constrained) versus 967–1638 m/s2; and headform speeds at the end of the loading phase were found to be 0.5–0.92 m/s (Constrained) versus 0.54–0.93 m/s. Differences between headform response for the two mounting arrangements were observed to be more substantial during the...
Strauß, P, Barthelmey, A & Deuse, J 2017, 'Cyber-physical systems for predictive maintenance', Productivity Management, vol. 22, no. 1, pp. 12-15.
View description>>
For an integral and constantly up-to-date image of adaptable production plants, sensor and process data as well as information on structure are required. Thus, the authors combine a low-cost sensor system for data acquisition in the production’s environment and an architecture for the automatic creation and maintenance of technical plant documentation. The effi cacy and relevance of the overall system will be demonstrated based on an application example concerning an electric monorail conveyor in automotive engineering.
Tong, L & Luo, Q 2017, 'A novel algorithm using an orthotropic material model for topology optimization', Engineering Optimization, vol. 49, no. 9, pp. 1523-1540.
View/Download from: Publisher's site
Trianni, A, Cagno, E & Neri, A 2017, 'Modelling barriers to the adoption of industrial sustainability measures', Journal of Cleaner Production, vol. 168, pp. 1482-1504.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Sustainability is constantly gaining relevance among industrial decision makers, policy makers and scholars. In order to be sustainable, firms need to implement industrial sustainability measures, however there are many barriers to doing this. This work is based on a review of literature on barriers to the areas of occupational health and safety, eco efficiency, energy efficiency and to sustainability, and contributes to industrial sustainability research by presenting a novel, integrated theoretical model of barriers to the implementation of sustainability measures. The model encompasses previous literature review contributions and is intended to characterize and evaluate barriers to the adoption of industrial sustainability measures in all its areas. We have conducted a preliminary validation of the model investigating eight northern Italian manufacturing firms, looking at its ability to represent barriers to sustainability, usefulness and ease of use. We conducted semi-structured interviews to people responsible of the different areas of industrial sustainability, complemented by questionnaires and secondary materials. Results show a positive overall judgment of the model by all the interviewees. Moreover, the model was able to be applied to issues deriving from different perspectives and different areas of industrial sustainability. The findings can help firms and policy makers overcome barriers and they also provide insight into the different perspectives on the adoption of industrial sustainability measures than can be used to promote their adoption.
Trianni, A, Cagno, E, Marchesani, F & Spallina, G 2017, 'Classification of drivers for industrial energy efficiency and their effect on the barriers affecting the investment decision-making process', Energy Efficiency, vol. 10, no. 1, pp. 199-215.
View/Download from: Publisher's site
View description>>
© 2016, Springer Science+Business Media Dordrecht. Industrial energy efficiency represents a priority for European industrial competitiveness. Many studies offer contributions providing evidence of the existence of driving forces supporting the adoption of energy efficiency measures, but a structured approach to drivers for industrial energy efficiency is still lacking. Therefore, in the present study, we propose a definition of drivers, making emphasis on the industrial decision-maker perspective, that is needed for their classification here proposed. Focus is given to point out the difference between internal and external drivers, highlighting the major stakeholders responsible for their promotion. Drivers are further categorized into: regulatory, economic, informative, and vocational training. Moreover, we propose a framework describing the effect of drivers on barriers in the decision-making process, as well as a preliminary identification of the major stakeholders to promote drivers. The study opens several opportunities for further research in the area of industrial energy efficiency.
Ulapane, N, Alempijevic, A, Vidal Calleja, T & Valls Miro, J 2017, 'Pulsed Eddy Current Sensing for Critical Pipe Condition Assessment', Sensors, vol. 17, no. 10, pp. 2208-2208.
View/Download from: Publisher's site
View description>>
© 2017 by the authors. Pulsed Eddy Current (PEC) sensing is used for Non-Destructive Evaluation (NDE) of the structural integrity of metallic structures in the aircraft, railway, oil and gas sectors. Urban water utilities also have extensive large ferromagnetic structures in the form of critical pressure pipe systems made of grey cast iron, ductile cast iron and mild steel. The associated material properties render NDE of these pipes by means of electromagnetic sensing a necessity. In recent years PEC sensing has established itself as a state-of-the-art NDE technique in the critical water pipe sector. This paper presents advancements to PEC inspection in view of the specific information demanded from water utilities along with the challenges encountered in this sector. Operating principles of the sensor architecture suitable for application on critical pipes are presented with the associated sensor design and calibration strategy. A Gaussian process-based approach is applied to model a functional relationship between a PEC signal feature and critical pipe wall thickness. A case study demonstrates the sensor’s behaviour on a grey cast iron pipe and discusses the implications of the observed results and challenges relating to this application.
Wang, S, Kodagoda, S, Shi, L & Wang, H 2017, 'Road-Terrain Classification for Land Vehicles: Employing an Acceleration-Based Approach', IEEE Vehicular Technology Magazine, vol. 12, no. 3, pp. 34-41.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. The perception of the environment around a land vehicle plays a crucial role for its driving assistant system. Knowledge of the road terrain is useful for handling its characteristics while driving the vehicles and improving passengers' safety and comfort. In this article, an approach to classifying road-terrain vehicles is presented. An accelerometer is mounted on the suspension of the vehicle to measure the vibration that represents the characteristics of the road terrain, and the road profile can be calculated by knowing the speed and one-quarter-dynamic model of the vehicle. The optimized classifier and features, speed independency, and the effect of employing principal component analysis (PCA) are investigated, and the simulation shows that this acceleration-based approach is feasible for land vehicles in a range of outdoor scenarios.
Wang, S, Kodagoda, S, Shi, L & Xu, N 2017, 'Lidar-based road terrain recognition for passenger vehicles', International Journal of Vehicle Design, vol. 74, no. 2, pp. 153-153.
View/Download from: Publisher's site
View description>>
Copyright © 2017 Inderscience Enterprises Ltd. The road terrain type is important information about a passenger vehicle’s surroundings. It suggests an appropriate control algorithm and driving strategy. In this paper, a Lidar sensor is employed to reconstruct the road surface and extract features for terrain classification. The experiment vehicle was driven on four specific road terrains at a variety of speeds. The speed dependency and the effect of using principal component analysis were investigated. The simulation experimental results show that this Lidar sensor-based approach is feasible and robust for passenger vehicles in a range of outdoor scenarios.
Wang, Y, Gao, J, Luo, Z, Brown, T & Zhang, N 2017, 'Level-set topology optimization for multimaterial and multifunctional mechanical metamaterials', Engineering Optimization, vol. 49, no. 1, pp. 22-42.
View/Download from: Publisher's site
View description>>
© 2016 Informa UK Limited, trading as Taylor & Francis Group. Metamaterials are artificially engineered composites designed to have unusual properties. This article will develop a new level-set based topology optimization method for the computational design of multimaterial metamaterials with exotic thermomechanical properties. In order to generate metamaterials consisting of arrays of microstructures under periodicity, the numerical homogenization method is used to evaluate the effective properties of the microstructure, and a multiphase level-set model is used to evolve the boundaries of the multimaterial microstructure. The proposed method will produce material geometries with distinct interfaces and smoothed boundaries, which may facilitate the fabrication of the topologically optimized designs. Several numerical cases are used to demonstrate the effectiveness of the proposed method.
Wei, D, Luo, L, Sato, H, Jiang, Z & Manabe, K 2017, 'Simulations of hydro-mechanical deep drawing using Voronoi model and real microstructure model', Procedia Engineering, vol. 207, pp. 1033-1038.
View/Download from: Publisher's site
View description>>
© 2017 The Authors. Published by Elsevier Ltd. Micro hydroforming is promising for fabricating complex micro components with a high aspect ratio. The aim of this study is to deepen the understanding of the size effects in micro hydroforming. Experimental work and FEM simulations of micro hydro-mechanical deep drawing (MHDD) were conducted. Voronoi model and real microstructure model were established. Real grain morphology can be considered in the real microstructure model. Local thinning in critical area of the drawn cups due to size effects can be predicted by the models. The simulation results agree with the MHDD test results.
Whyte, T, Gibson, T, Eager, D & Milthorpe, B 2017, 'Full-face motorcycle helmet protection from facial impacts: an investigation using THOR dummy impacts and SIMon finite element head model', Injury Prevention, vol. 23, no. 3, pp. 205-210.
View/Download from: Publisher's site
View description>>
© 2017, BMJ Publishing Group. All rights reserved. Objective Facial impacts are both common and injurious for helmeted motorcyclists who crash; however, there is no facial impact requirement in major motorcycle helmet standards. This study examined the effect of fullface motorcycle helmet protection on brain injury risk in facial impacts using a test device with biofidelic head and neck motion. A preliminary investigation of energy absorbing foam in the helmet chin bar was carried out. Method Flat-faced rigid pendulum impacts were performed on a THOR dummy in an unprotected (no helmet) and protected mode (two full-face helmet conditions). The head responses of the dummy were input into the simulated injury monitor finite element head model to analyse the risk of brain injury in these impacts. Results Full-face helmet protection provides a significant reduction in brain injury risk in facial impacts at increasing impact speeds compared with an unprotected rider (p<0.05). The effect of low-density crushable foam added to the chin bar could not be distinguished from an unpadded chin bar impact. Conclusions Despite the lack of an impact attenuation requirement for the face, full-face helmets do provide a reduction in head injury risk to the wearer in facial impacts. The specific helmet design factors that influence head injury risk in facial impacts need further investigation if improved protection for helmeted motorcyclists is to be achieved.
Wickramasooriya Kuruneru, ST, Sauret, E, Saha, SC & Gu, Y 2017, 'A Novel Experimental Method to Assess Particle Deposition in Idealized Porous Channels', Heat Transfer Engineering, vol. 38, no. 11-12, pp. 1008-1017.
View/Download from: Publisher's site
View description>>
© 2017 Queensland University of Technology. A novel and economical experimental technique has been developed to assess industrial aerosol deposition in various idealized porous channel configurations. This judicious examination of aerosol penetration in porous channels will assist engineers to better optimize designs for various engineering applications. Deposition patterns differ with porosity due to geometric configurations of the channel and superficial inlet velocities. Interestingly, it is found that two configurations of similar porosity exhibit significantly higher deposition fractions. Inertial impaction is profound at the leading edge of all obstacles, whereas particle buildup is observed at the trailing edge of the obstructions. A qualitative analysis shows that the numerical results are in good agreement with experimental results.
Wight, NM, Acosta, E, Vijayaraghavan, RK, McNally, PJ, Smirnov, V & Bennett, NS 2017, 'A universal method for thermal conductivity measurements on micro-/nano-films with and without substrates using micro-Raman spectroscopy', Thermal Science and Engineering Progress, vol. 3, pp. 95-101.
View/Download from: Publisher's site
View description>>
The ability to measure intrinsic thermal conductivity via a non-contact, non-destructive process is extremely attractive. Micro-Raman spectroscopy has been demonstrated to enable effective non-contact thermometry with further work providing a non-destructive estimation of values for thermal conductivity on suitable materials. However significant limitations remain for nano- and micro-films. Materials that do not meet dimensional requirements for thickness or that are in-situ on a substrate or supporting structure present significant challenges using existing approaches. For such samples, representative measurements must be obtained using alternative methods that can compromise samples and/or require relative complexity in experimental design and analysis. Here an analytical model is shown allowing thermal conductivity to be measured free of such limitations via a straightforward approach using micro-Raman spectroscopy. Results are then obtained experimentally and values compared with those obtained using a complimentary technique demonstrating an improved accuracy over existing micro-Raman approaches. Furthermore, this model enables the effect of any substrate or supporting structure on measured values to be quantified and estimations for thermal conductivity of the sample itself to then be calculated where an influence is determined. Current estimations determining the threshold of substrate influence are shown to be insufficient and the importance of obtaining values of thermal conductivity for samples themselves under such conditions is demonstrated.
Wöstmann, R, Strauss, P & Deuse, J 2017, 'Predictive Maintenance in production', WT Werkstattstechnik, vol. 107, no. 7-8, pp. 524-529.
View description>>
Due to new possibilities of connectivity and data processing of assets and components, predictive maintenance has gained a growing importance. While it has been used in aerospace, supply or energy technology for many years, there are still few applications to be found within production. This paper outlines unused potential in presenting a classification of existing predictive maintenance applica- tions and their transferability to production as well as prerequisites for a successful implementation.
Wu, J, Luo, Z, Li, H & Zhang, N 2017, 'A new hybrid uncertainty optimization method for structures using orthogonal series expansion', Applied Mathematical Modelling, vol. 45, pp. 474-490.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Inc. This paper proposes a new hybrid uncertain design optimization method for structures which contain both random and interval variables simultaneously. The optimization model is formulated with the feasible robustness and the reliability of the worst scenario. The hybrid uncertainty is quantified by using the orthogonal series expansion method that integrates the Polynomial Chaos (PC) expansion method and the Chebyshev interval method within a uniform framework. The design sensitivity of objective and constraints will be developed to greatly facilitate the use of gradient-based optimization algorithms. The numerical results show that this method will be more possible to seek the feasible solution.
Wu, J, Luo, Z, Zhang, N, Zhang, Y & Walker, PD 2017, 'Uncertain dynamic analysis for rigid-flexible mechanisms with random geometry and material properties', Mechanical Systems and Signal Processing, vol. 85, no. 15, pp. 487-511.
View/Download from: Publisher's site
View description>>
© 2016 Elsevier Ltd This paper proposes an uncertain modelling and computational method to analyze dynamic responses of rigid-flexible multibody systems (or mechanisms) with random geometry and material properties. Firstly, the deterministic model for the rigid-flexible multibody system is built with the absolute node coordinate formula (ANCF), in which the flexible parts are modeled by using ANCF elements, while the rigid parts are described by ANCF reference nodes (ANCF-RNs). Secondly, uncertainty for the geometry of rigid parts is expressed as uniform random variables, while the uncertainty for the material properties of flexible parts is modeled as a continuous random field, which is further discretized to Gaussian random variables using a series expansion method. Finally, a non-intrusive numerical method is developed to solve the dynamic equations of systems involving both types of random variables, which systematically integrates the deterministic generalized-α solver with Latin Hypercube sampling (LHS) and Polynomial Chaos (PC) expansion. The benchmark slider-crank mechanism is used as a numerical example to demonstrate the characteristics of the proposed method.
Yan, Y, Sencadas, V, Jin, T, Huang, X, Chen, J, Wei, D & Jiang, Z 2017, 'Tailoring the wettability and mechanical properties of electrospun poly(l-lactic acid)-poly(glycerol sebacate) core-shell membranes for biomedical applications', Journal of Colloid and Interface Science, vol. 508, pp. 87-94.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Inc. Tissue and biomedical engineering fields are in constant mutation and in searching for innovative processing techniques capable to tailor the material properties. In this work, poly(L-lactic acid) (PLLA) and elastomeric poly(glycerol sebacate) (PGS) were dissolved in the same solvents and electrospun together, in a single needle system. A core-shell structure where the hydrophilic PGS was placed onto the surface of the hydrophobic PLLA fibre was obtained for elastomeric concentrations up to 25 wt%. It was found that the PLLA:PGS blends are immiscible and the blends present the melting temperatures of the individual polymers. Moreover, their surface properties were deeply influenced by the presence of the PGS, and a superhydrophilic membrane was obtained, after PGS curing at 120 °C for 48 h. When the concentration of PGS is up to 25 wt%, the blend's Young modulus decreases from ∼35.9 ± 7.1 to 7.5 ± 1.4 MPa and a twofold improvement in the sample stretchability was observed, compared with the pristine PLLA electrospun samples. Finally, in vitro hypothalamus A59 nerve cell culture shows that the core-shell electrospun samples enhanced cell adhesion and proliferation, suggesting that these developed materials have great potentials for nerve regeneration and biomedical engineering applications.
Yan, Y, Sencadas, V, Zhang, J, Wei, D & Jiang, Z 2017, 'Superomniphilic Poly(glycerol sebacate)–Poly(l‐lactic acid) Electrospun Membranes for Oil Spill Remediation', Advanced Materials Interfaces, vol. 4, no. 20, pp. 1700484-1700484.
View/Download from: Publisher's site
View description>>
AbstractSuperomniphilic materials are defined as materials that can uptake both water and oil‐like liquids. In this study, a facile method to prepare a superomniphilic and biodegradable core–shell structure of poly(glycerol sebacate) (PGS) and poly(l‐lactic acid) (PLLA) is reported. The developed method immobilizes the PGS polymer onto the surface of the PLLA electrospun fibers, increasing the presence of hydroxyl groups on the surface of the membranes. The sample with 25 wt% PGS can uptake polar and apolar solvents, and presents a superhydrophilic behavior. The PGS‐PLLA composite is reusable up to 10 cycles of solvent (water of organic solvents) absorption with a separation efficiency of 99.5%, and its general appearance resembles the first absorption/compression cycle. Finally, this work presents a novel biodegradable polymeric blend membrane with superomniphilic properties, produced by a scalable process, which could be easily implemented to fight against environmental disasters such as large area oil spills.
Yan, Y, Sencadas, V, Zhang, J, Zu, G, Wei, D & Jiang, Z 2017, 'Processing, characterisation and electromechanical behaviour of elastomeric multiwall carbon nanotubes-poly (glycerol sebacate) nanocomposites for piezoresistive sensors applications', Composites Science and Technology, vol. 142, pp. 163-170.
View/Download from: Publisher's site
View description>>
© 2017 Elsevier Ltd Highly stretchable elastomeric multiwall carbon nanotubes – poly (glycerol sebacate) (MWCNT-PGS) nanocomposites were prepared by mixing conductive multiwall carbon nanotubes (MWCNTs) with PGS prepolymer and curing at 120 °C. The incorporation of conductive filler increases the matrix crosslinking density and mechanical stiffness without loss of the flexibility and elasticity of the polymeric network with low mechanical hysteresis behaviour. The percolation threshold for the electrical conductivity was found to be ∼1 wt% of MWCNTs. The piezoresistive behaviour of the prepared samples shows a negative gauge factor (GF) between −0.5 and −0.8 under uniaxial tensile stress, probably due to geometrical factors, whilst under 3-point bending the calculated GF values were positive and a maximum GF = 42 was achieved for the samples with 2 wt% MWCNTs. Overall, the unique property combination between the MWCNTs and the PGS make them potentially suitable for the development of large deformation piezoresistive sensors, especially for biomedical engineering applications, flexible and wearable devices.
Yang, N, Yee, J, Zheng, B, Gaiser, K, Reynolds, T, Clemon, L, Lu, WY, Schoenung, JM & Lavernia, EJ 2017, 'Process-Structure-Property Relationships for 316L Stainless Steel Fabricated by Additive Manufacturing and Its Implication for Component Engineering', Journal of Thermal Spray Technology, vol. 26, no. 4, pp. 610-626.
View/Download from: Publisher's site
View description>>
© 2016, ASM International. We investigate the process-structure-property relationships for 316L stainless steel prototyping utilizing 3-D laser engineered net shaping (LENS), a commercial direct energy deposition additive manufacturing process. The study concluded that the resultant physical metallurgy of 3-D LENS 316L prototypes is dictated by the interactive metallurgical reactions, during instantaneous powder feeding/melting, molten metal flow and liquid metal solidification. The study also showed 3-D LENS manufacturing is capable of building high strength and ductile 316L prototypes due to its fine cellular spacing from fast solidification cooling, and the well-fused epitaxial interfaces at metal flow trails and interpass boundaries. However, without further LENS process control and optimization, the deposits are vulnerable to localized hardness variation attributed to heterogeneous microstructure, i.e., the interpass heat-affected zone (HAZ) from repetitive thermal heating during successive layer depositions. Most significantly, the current deposits exhibit anisotropic tensile behavior, i.e., lower strain and/or premature interpass delamination parallel to build direction (axial). This anisotropic behavior is attributed to the presence of interpass HAZ, which coexists with flying feedstock inclusions and porosity from incomplete molten metal fusion. The current observations and findings contribute to the scientific basis for future process control and optimization necessary for material property control and defect mitigation.
Yu, J, Ji, J, Miao, Z & Zhou, J 2017, 'Adaptive formation control of networked Lagrangian systems with a moving leader', Nonlinear Dynamics, vol. 90, no. 4, pp. 2755-2766.
View/Download from: Publisher's site
View description>>
© 2017, Springer Science+Business Media B.V. This paper investigates the formation control problem of networked Lagrangian systems with a moving leader under the directed network topology. A special form of geometric pattern is introduced to design the desired formation for such systems. Three adaptive control strategies are proposed for the networked Lagrangian systems to achieve the formation for the cases of the absence and presence of time delays. Some simple yet general algebraic criteria are developed to ensure that the networked Lagrangian systems can always achieve desired geometric formation. Furthermore, the effect of communication time delays on the performance of formation control is numerically investigated. Finally, numerical examples are given to illustrate and visualize the effectiveness of the theoretical results.
Zhang, J, Xiao, W, Zhang, S & Huang, S 2017, 'Device-Free Localization via an Extreme Learning Machine with Parameterized Geometrical Feature Extraction', Sensors, vol. 17, no. 4, pp. 879-879.
View/Download from: Publisher's site
View description>>
© 2017 by the authors. Licensee MDPI, Basel, Switzerland. Device-free localization (DFL) is becoming one of the new technologies in wireless localization field, due to its advantage that the target to be localized does not need to be attached to any electronic device. In the radio-frequency (RF) DFL system, radio transmitters (RTs) and radio receivers (RXs) are used to sense the target collaboratively, and the location of the target can be estimated by fusing the changes of the received signal strength (RSS) measurements associated with the wireless links. In this paper, we will propose an extreme learning machine (ELM) approach for DFL, to improve the efficiency and the accuracy of the localization algorithm. Different from the conventional machine learning approaches for wireless localization, in which the above differential RSS measurements are trivially used as the only input features, we introduce the parameterized geometrical representation for an affected link, which consists of its geometrical intercepts and differential RSS measurement. Parameterized geometrical feature extraction (PGFE) is performed for the affected links and the features are used as the inputs of ELM. The proposed PGFE-ELM for DFL is trained in the offline phase and performed for real-time localization in the online phase, where the estimated location of the target is obtained through the created ELM. PGFE-ELM has the advantages that the affected links used by ELM in the online phase can be different from those used for training in the offline phase, and can be more robust to deal with the uncertain combination of the detectable wireless links. Experimental results show that the proposed PGFE-ELM can improve the localization accuracy and learning speed significantly compared with a number of the existing machine learning and DFL approaches, including the weighted K-nearest neighbor (WKNN), support vector machine (SVM), back propagation neural network (BPNN), as well as the we...
Zhang, T, Wu, K, Song, J, Huang, S & Dissanayake, G 2017, 'Convergence and Consistency Analysis for a 3-D Invariant-EKF SLAM', IEEE Robotics and Automation Letters, vol. 2, no. 2, pp. 733-740.
View/Download from: Publisher's site
View description>>
© 2016 IEEE. In this letter, we investigate the convergence and consistency properties of an invariant-extended Kalman filter (RI-EKF) based simultaneous localization and mapping (SLAM) algorithm. Basic convergence properties of this algorithm are proven. These proofs do not require the restrictive assumption that the Jacobians of the motion and observation models need to be evaluated at the ground truth. It is also shown that the output of RI-EKF is invariant under any stochastic rigid body transformation in contrast to SO(3) based EKF SLAM algorithm (SO(3)-EKF) that is only invariant under deterministic rigid body transformation. Implications of these invariance properties on the consistency of the estimator are also discussed. Monte Carlo simulation results demonstrate that RI-EKF outperforms SO(3)-EKF, Robocentric-EKF and the 'First Estimates Jacobian' EKF, for three-dimensional point feature-based SLAM.
Zhao, S, Cheng, E, Qiu, X, Burnett, I & Liu, JC-C 2017, 'Wind noise spectra in small Reynolds number turbulent flows', The Journal of the Acoustical Society of America, vol. 142, no. 5, pp. 3227-3233.
View/Download from: Publisher's site
View description>>
Wind noise spectra caused by wind from fans in indoor environments have been found to be different from those measured in outdoor atmospheric conditions. Although many models have been developed to predict outdoor wind noise spectra under the assumption of large Reynolds number [Zhao, Cheng, Qiu, Burnett, and Liu (2016). J. Acoust. Soc. Am. 140, 4178–4182, and the references therein], they cannot be applied directly to the indoor situations because the Reynolds number of wind from fans in indoor environments is usually much smaller than that experienced in atmospheric turbulence. This paper proposes a pressure structure function model that combines the energy-containing and dissipation ranges so that the pressure spectrum for small Reynolds number turbulent flows can be calculated. The proposed pressure structure function model is validated with the experimental results in the literature, and then the obtained pressure spectrum is verified with the numerical simulation and experiment results. It is demonstrated that the pressure spectrum obtained from the proposed pressure structure function model can be utilized to estimate wind noise spectra caused by turbulent flows with small Reynolds numbers.
Zhao, S, Dabin, M, Cheng, E, Qiu, X, Burnett, I & Liu, JC-C 2017, 'On the wind noise reduction mechanism of porous microphone windscreens', The Journal of the Acoustical Society of America, vol. 142, no. 4, pp. 2454-2463.
View/Download from: Publisher's site
View description>>
This paper investigates the wind noise reduction mechanism of porous microphone windscreens. The pressure fluctuations inside the porous windscreens with various viscous and inertial coefficients are studied with numerical simulations. The viscous and inertial coefficients represent the viscous forces resulting from the fluid–solid interaction along the surface of the pores and the inertial forces imposed on the fluid flow by the solid structure of the porous medium, respectively. Simulation results indicate that the wind noise reduction first increases and then decreases with both viscous and inertial coefficients after reaching a maximum. Experimental results conducted on five porous microphone windscreens with porosity from 20 to 60 pores per inch (PPI) show that the 40 PPI windscreen has the highest wind noise reduction performance, and this supports the simulation results. The existence of the optimal values for the viscous and inertial coefficients is explained qualitatively and it is shown that the design of the porous microphone windscreens should take into account both the turbulence suppression inside and the wake generation behind the windscreen to achieve optimal performance.
Zwinkau, R, Müller, P & Deuse, J 2017, 'Korrelierende Prozessparameter bei der Reinigung mit Druckluft in Fließlinien', JOT Journal für Oberflächentechnik, vol. 57, no. 11, pp. 62-65.
View/Download from: Publisher's site
Abdo, P & Huynh, BP 1970, 'Effect of Combining Buoyancy Driven and Winddriven Ventilation in a Two Dimensional Room Fitted With a Windcatcher', Volume 7: Fluids Engineering, ASME 2017 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Tampa, Florida, pp. 1-7.
View/Download from: Publisher's site
View description>>
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 ventilation, or stack ventilation. The most efficient design for natural ventilation in buildings should implement both types of natural ventilation. Stack ventilation which is temperature induced is driven by buoyancy making it less dependent on wind and its direction. Heat emitted causes a temperature difference between two adjoining volumes of air, the warmer air will have lower density and be more buoyant thus will rise above the cold air creating an upward air stream. Combining the winddriven and the buoyancy driven ventilation will be investigated in this study through the use of a windcatcher natural ventilation system. Stack driven air rises as it leaves the windcatcher and it is replaced with fresh air from outside as it enters through the positively pressured windward side. 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 the winddriven ventilation alone and on the combined buoyancy and winddriven ventilation.
Abdo, P, Huynh, BP & Avakian, V 1970, 'Distribution of Air Flow Through a Green Wall Module', Volume 1B, Symposia: Fluid Measurement and Instrumentation; Fluid Dynamics of Wind Energy; Renewable and Sustainable Energy Conversion; Energy and Process Engineering; Microfluidics and Nanofluidics; Development and Applications in Computational Fluid Dynamics; DNS/LES and Hybrid RANS/LES Methods, ASME 2017 Fluids Engineering Division Summer Meeting, American Society of Mechanical Engineers, Waikoloa, Hawaii, USA.
View/Download from: Publisher's site
View description>>
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. A green wall can be found indoors as well as outdoors, and could be assembled from modules in an arrangement similar to tiling. The module is a rectangular plastic box (dimensions about 500 mm × 500 mm × 130 mm) that holds a permeable bag containing a plant-growing medium (replacement for soil). The front face of the module has multiple openings for plants to protrude out from the bag inside. Plant roots are imbedded in the medium. 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 remove both gaseous and particulate pollutants from the air. Volatile Organic compounds (VOCs) and particulate matters PMs are both reduced by passing through the plant-growing medium, thus reducing the percentage of air flow that passes through the open top face of the module is essential to maximize the capacity of bio-filtration. Drip-irrigation water is dispensed from a tube running along the open top-face of the module. The module has also a small drainage hole on its bottom face. Pressure drop across the module as well as air-flow rate through it have been obtained in a previous work [1], air-flow distribution through the module and the effect of introducing a cover to the module’s open top face are investigated in this work to improve the design of the module and achieve more appropriate flow rate and flow distribution. The top cover essentially includes small holes of 10 mm diameter to allow the necessary irrigation. The measurements help to determine the pattern of flow resistances which in turn will be used in a future CFD (Computational Fluid Dynamics) analysis.
Alvarez, JK, Sutjipto, S & Kodagoda, S 1970, 'Validated ground penetrating radar simulation model for estimating rebar location in infrastructure monitoring', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1460-1465.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Biogenic sulphide corrosion of reinforced concrete sewer pipes is an ongoing problem for wastewater governing bodies. Ensuring Workplace Health and Safety (WHS) is also an issue due to the harsh nature of sewer environments. As such, research into technologies that allow for automatic unmanned site assessments are of major priority to wastewater managing utilities. The use of Ground Penetrating Radar (GPR) is currently being investigated for it's ability to provide subsurface images. However, the GPR technology has not been tested and validated in harsh sewer environments. It is anticipated that the GPR interpretation can be hindered by low signal to noise ratio. As data driven machine learning techniques have proven to work in higly challenging data, our intenetion is to apply such techniques in GPR data processing. However, this is hindered by the lack of large amount of training data as it is prohibitively hard to collect such real experimental testing data. Thus, the aim of this study is to validate a ground penetrating radar simulation software, gprMax, and test it for suitability in generating realistic, big data sets with which to train the aforementioned data driven machine learning models supplemented with actual sewer crown data. The results of the study is the validation of the GPR simulator, tuned and able to generate reasonably realistic data. A novel concrete analog was also developed to allow for ease of testing of various parameters such as rebar cover depths and rebar spacing.
Ang, CS, Killen, CP & Sankaran, S 1970, 'Making sense of project portfolio value in practice', The Modern Project: Mindsets, Toolsets, and Theoretical Frameworks, Proceedings of IRNOP 2017, International Research Network on Organising by Projects, Boston.
Arukgoda, J, Ranasinghe, R, Dantanarayana, L, Dissanayake, G & Furukawa, T 1970, 'Vector Distance Function Based Map Representation for Robot Localisation', Australasian Conference on Robotics and Automation, Australasian Conference on Robotics and Automation, ACRA, Sydney Australia, pp. 1-8.
View description>>
This paper introduces the use of the vectordistance function (VDF) for representing environments,particularly for the use in localisationalgorithms. It is shown that VDF hasa continuous derivative at the object boundaryin contrast to unsigned distance transform,and does not require an environment populatedwith closed object as in the case of thesigned distance transforms, the two most commonstrategies reported in the literature forrepresenting environments based on distancesto nearest occupied regions. As such VDF overcomesthe main disadvantages of the existingdistance transform based representations in thecontext of robot localisation. The key propertiesof VDF are demonstrated and the use ofVDF in robot localisation using an optimizationbased algorithm is illustrated using threeexamples. It is shown that the proposed environmentrepresentation and the localisationalgorithm is effective in providing accurate locationestimates as well as the associated uncertainties
Arukgoda, J, Ranasinghe, R, Danthanarayana, L, Dissanayake, G & Furukawa, T 1970, 'Vector distance function based map representation for robot localisation', Australasian Conference on Robotics and Automation, ACRA, pp. 165-172.
View description>>
This paper introduces the use of the vector distance function (VDF) for representing environments, particularly for the use in localisation algorithms. It is shown that VDF has a continuous derivative at the object boundary in contrast to unsigned distance transform, and does not require an environment populated with closed object as in the case of the signed distance transforms, the two most common strategies reported in the literature for representing environments based on distances to nearest occupied regions. As such VDF overcomes the main disadvantages of the existing distance transform based representations in the context of robot localisation. The key properties of VDF are demonstrated and the use of VDF in robot localisation using an optimization based algorithm is illustrated using three examples. It is shown that the proposed environment representation and the localisation algorithm is effective in providing accurate location estimates as well as the associated uncertainties.
Brennan, MJ, Karimi, M, Almeida, FCL, de Lima, FK, Ayala, PC, Obata, D, Paschoalini, AT & Kessissoglou, N 1970, 'On the role of vibro-acoustics in leak detection for plastic water distribution pipes', Procedia Engineering, Elsevier BV, pp. 1350-1355.
View/Download from: Publisher's site
Carmichael, MG, Aldini, S & Liu, D 1970, 'Human user impressions of damping methods for singularity handling in human-robot collaboration', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney Australia, pp. 107-113.
View description>>
Kinematic singularity is a fundamental and well understood problem of robot manipulators, with many methods having been developed to ensure safe and robust operation in proximity to singularity. However little attention has been given to the scenario where the robot and human are working in physical contact to collaboratively perform a task. In such a scenario the feelings and impressions of the human operator should be considered when developing solutions for handling singularity. This work presents an experimental study comparing three modes of handling kinematic singularities with respect to the impressions of the human operator. Two of the modes are based on traditional Damped-Least-Squares. The third method uses an asymmetric damping behavior proposed as being well suited for applications involving physical human-robot interaction. The three modes are tested and compared by subjects performing a mock industrial task, and feedback from the subjects analyzed to identify the preferred mode. Results indicate that the choice of method used affects the user's impressions of the interaction, and the asymmetrical damping behavior can produce a preferred interaction experience with human operators during tasks.
Chen, S, Doan, VH & Zhao, L 1970, 'Heart simulator: A periodic pump to simulate the cardiac motion in an aortic test-rig', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney, Australia, pp. 100-106.
View description>>
A periodic pump that simulates blood ejection from human heart to aorta is the core element for building an aortic robotics test-rig. This paper is to describe the design of such a prototype human heart simulator and its performance under different working status, such as simulating the physiological states of a healthy adult and/or a child in sleep, relax and physical exercise. By balancing the cost and performance, this prototype has these specifications: (1) Using ordinary plumbing components and water to simulate the cardiac motion and blood flow. (2) Simulating the volume change of human heart chamber by controlling movement of a mechanical piston. (3) Performing a friendly user interface and delicate control via a MCU system with high reliability. (4) Simulated physiological output parameters such as volume per stroke, heart beat rate and waveform can be easily adjusted and monitored in real-time.
Chen, Y, Huang, S, Fitch, R & Yu, J 1970, 'Efficient active SLAM based on submap joining', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney, Australia, pp. 141-147.
View description>>
This paper considers the active SLAM problem where a robot is required to cover a given area while at the same time performing simultaneous localization and mapping (SLAM) for understanding the environment and localizing the robot itself. We propose a model predictive control (MPC) framework, and the minimization of uncertainty in SLAM and coverage problems are solved respectively by the Sequential Quadratic Programming (SQP) method. Then, a decision making process is used to control the switching of two control inputs. In order to reduce the estimation and planning time, we use Linear SLAM, which is a submap joining approach. Simulation results are presented to validate the effectiveness of the proposed active SLAM strategy.
Chung, H, Montiel, F, Karimi, M & Kessissoglou, N 1970, 'Acoustic pressure fields of 2D elastic cylindrical shells', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, 46th International Congress and Exposition on Noise Control Engineering, Hong Kong, China.
View description>>
The acoustic pressure field of a 2D elastic cylindrical shell excited by an incident plane wave is analytically and numerically presented. The pressure field is computed by solving the Helmholtz and elastic thin shell equations that are coupled by the kinematic conditions on both the interior and exterior surfaces of the shell. The acoustic pressure is expressed as series of Bessel and Hankel functions that are the eigenfunctions of the Helmholtz equation in 2D polar coordinates. As a result, the solution can be computed without discretization of the physical domains and the cylindrical shell. The method is then implemented to compute the acoustic fields around a C-shaped cylinder, which has the Helmholtz resonator configuration. Results from the analytical model are compared to results from a finite element solution.
Collart, J, Fitch, R & Alempijevic, A 1970, 'Motion states inference through 3D shoulder gait analysis and Hierarchical Hidden Markov Models', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney, Australia, pp. 173-180.
View description>>
Automatically inferring human intention from walking movements is an important research concern in robotics and other fields of study. It is generally derived from temporal motion of limb position relative to the body. These changes can also be reected in the change of stance and gait. Conventional systems relying on gait are usually based on tracking the lower body motion (hip, foot) and are extracted from monocular camera data. However, such data can be inaccessible in crowded environments where occlusions of the lower body are prevalent. This paper proposes a novel approach to utilize upper body 3D-motion and Hierarchical Hidden Markov Models to estimate human ambulatory states, such as quietly standing, starting to walk (gait initiation), walking (gait cycle), or stopping (gait termination). Methods have been tested on real data acquired through a motion capture system where foot measurements (heels and toes) were used as ground truth data for labeling the states to train and test the models. Current results demonstrate the feasibility of using such a system to infer lower-body motion states and sub-states through observations of 3D shoulder motion online. Our results enable applications in situations where only upper body motion is readily observable.
Eager, D & Chapman, C 1970, 'Vibration measurement as a tool to solve a murder', ICBEN, ICBEN, Organizers Switzerland Ltd., Zurich, Switzerland.
View description>>
This paper will discuss a novel use of vibration measurement used to assist the NSW Police Force to solve the ‘pogo stick’ murder.The authors were approached by the Homicide Squad regarding a suspicious death of a 7-year boy at Oatley in May 2013. The child had reportedly fallen from a pogo stick and suffered significant head injuries. The child had not been provided with medical attention after the fall and died some 24 hours later.The incident occurred inside a small unit which was used as a music recording studio. The studio is on the first level of a larger business complex. The studio consisted of a recording room, a lounge room, and a kitchenette. The child fell in the lounge room. At the time of the alleged incident the mother was in the kitchenette, and the accused was in the recording room. According to the accused, he had headphones on and was listening to loud music when he 'felt' the vibration of the thud.Kodi Maybir was found guilty of murder in November 2015.
Eager, D, Chapman, C & Nguyen, AV 1970, 'Test method for longitudinal performance of impact attenuating surfaces', 7th International Conference on Mechanics and Materials in Design, 7th International Conference on Mechanics and Materials in Design, INEGI/FEUP, Albufeira, Portugal, pp. 149-150.
View description>>
The current test method for impact attenuation for children’s playground surfacing EN 1177 does not include a longitudinal test method to measure the expected life of the impact attenuating surface.This work proposes a test method to measure the accelerated usage of impact attenuating surfaces installed within children’s playgrounds.
Ebadi, A & Ji, J 1970, 'Investigation & comparison of the integration of flywheel energy storage in hybrid electric and electric vehicles using bond graphs', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia, pp. 1-6.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Over the past few years Hybrid Electric and Electric propulsion systems have found significant attention as the most plausible substitute to fossil fuel based engines. Hybrid Electric Vehicles (HEV) have been around for more than a decade and extensive research has been taken out to make these vehicles more efficient. With advances in technology, manufacturers such as Tesla and Chevrolet have successfully launched a number of Electric Vehicles (EV) in the past 5 years. In despite of all this success, HEVs and EVs currently face challenges in energy storage systems (ESS) with regard to a variety of parameters and to overcome these issues research has been done on different types of ESS systems to extend the range of such vehicles. Flywheel Energy Storage Systems (FESS) have regained interest in the last decade and the application of kinetic energy recovery system (KERS) in the Formula 1 has reinforced the case of using FESS in HEV and EV. In this study, the integration of an FESS system within a hybrid electric propulsion and an electric propulsion system is considered and with the help of Bond-Graphs as a multidisciplinary modelling tool the impact of this integration is analyzed and compared with each other.
Figgemeier, E, Wells, L, Becker, L & Sick, N 1970, 'Implications of Cycle Stability of Silicon Alloy Anodes on Driving Range, Costs and Business Models of Electric Vehicles', Batteries Event 2017, Nice, France.
Furukawa, T, Kang, C, Li, B & Dissanayake, G 1970, 'Multi-stage Bayesian target estimation by UAV using fisheye lens camera and pan/tilt camera', 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Vancouver, BC, Canada, pp. 4167-4172.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. This paper presents a generalized multi-stage Bayesian approach for an unmanned aerial vehicle to estimate the location of a mobile target. The major hardware components of the proposed approach are a camera with a fisheye lens and another camera with a normal lens and a pan/tilt unit. With wide angle of view (AOV), the fisheye lens camera first detects the bearing of the target, and the PT camera next captures the target in its AOV. The recursive Bayesian estimation steadily locates the target in a globally defined space. The paper also proposes a multi-stage detection method for the fisheye lens camera. The level of confidence is defined in association with the probability of detection (POD) for each detection technique, and the fisheye lens enables continuous detection by gradually increasing the POD. The observation likelihood is finally derived from the POD in a generalized manner. The proposed approach was applied to the detection of a mobile target by a multi-rotor helicopter, and results have demonstrated the effectiveness of both the proposed multi-stage Bayesian approach and multi-stage fisheye lens detection method.
Guertler, MR, Kriz, A, McGregor, C, Bankins, S & Bucolo, S 1970, '“And Action!” – Rigour Meets Relevance in Action Innovation Management (AIM)', ISPIM, The XXVIII ISPIM Innovation Conference, Vienna, Austria, pp. 1-1.
View description>>
Innovation management comprises a complex interplay of various actors and processes within a socio-technical quadruple-helix. Traditional research approaches often struggle to manage this complexity and risk irrelevance and “so what results”. Use of merely mono-disciplinary methods forces researchers to choose between research depth and breadth. This results in isolated views and missing links between phenomena. Action Research (AR) represents interdisciplinary research, in collaboration with industry clients in real world settings. AR combines and extends scientific knowledge and theory development through client-researcher practical problem solving and competence building. This paper discusses benefits and challenges of AR in innovation management and presents an “Action Innovation Management (AIM)” process-model to encourage purposeful application of AR within the domain of innovation management. Along with supporting the use of AR, the goal is to foster scientific discussion of how AIM can still achieve “good science” with twin benefits of rigour and relevance.
Guertler, MR, O'Donnell, M & MacCarthy, A 1970, 'Enabling Open Innovation in Defence through design-thinking', yes, The ISPIM Innovation Summit – Building the Innovation Century, ISPIM, Melbourne, pp. 1-19.
View description>>
Open Innovation (OI) has gained increasing popularity and application in varies areas. However, there have still been areas with only limited OI application, which have been traditionally considered as “closed” such as Defence. Due to changing governmental agendas, Defence – in particular the Australian Defence Forces – sees an increasing benefit to opening up and engaging more fully with external partners. As part of a larger research program, this paper presents a pilot project, which explores the application of OI in the context of procurement in Defence. In this respect, it particularly analyses the role of design-thinking as an enabler for collaboration between actors from different disciplines, for building a mutual understanding and co-creating a novel solution. Our results prove the successful application of OI in Defence, and the enabling role of design-thinking on an operational problem solving level as well as on a strategic level to achieve a sustainable organisational change in Defence.
Hadgraft, RG, Francis, B, Lawson, J, Jarman, R, Stewart, C, Hsieh, I & Jenkins, G 1970, 'Curriculum transformation with students as partners', Proceedings of the 28th Annual Conference of the Australasian Association for Engineering Education (AAEE 2017), Annual Conference of the Australasian Association for Engineering, Australasian Association for Engineering Education, Manly, Australia, pp. 1-9.
View description>>
8732142. That was my student ID as an undergraduate (now one of the authors).It was a number, not a name. It distinguished students from professors and all other teachingstaff and, in a symbolic way, reminded us all of our firm place as students, as learners. Therewas a big power differential between students and teachers in the 1980s. What we learnedwas prescribed, transmitted and tested in implicit ways (no rubrics or marking criteria in thosedays) and rarely were our skills tested – just what we knew and could recall at a given time.Sometimes people say that teaching is an act. Indeed, sage on the stage suggests thisprecisely. But being a student is also an act. Students also assume roles and personas.If we want curriculum transformation, we seek to put a stop to acting – to engage studentsand staff in authentic learning.MIDAS is our curriculum transformation project in the Faculty of Engineering and InformationTechnology (FEIT) at UTS – More Innovative Design-Able Students. In MIDAS, we wantstudents and teachers to be their authentic selves in a true teaching and learningpartnership. MIDAS seeks mutual respect in people, not the fulfilment of roles.MIDAS doesn’t see students as numbers, but as partners, as people who can learn,contribute, inspire, teach and create … and it sees teachers as people who also learn,contribute, inspire, teach and create
Han, H, Paul, G & Matsubara, T 1970, 'Model-based reinforcement learning approach for deformable linear object manipulation', 2017 13th IEEE Conference on Automation Science and Engineering (CASE), 2017 13th IEEE Conference on Automation Science and Engineering (CASE 2017), IEEE, Xi'an, China, pp. 750-755.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Deformable Linear Object (DLO) manipulation has wide application in industry and in daily life. Conventionally, it is difficult for a robot to manipulate a DLO to achieve the target configuration due to the absence of the universal model that specifies the DLO regardless of the material and environment. Since the state variable of a DLO can be very high dimensional, identifying such a model may require a huge number of samples. Thus, model-based planning of DLO manipulation would be impractical and unreasonable. In this paper, we explore another approach based on reinforcement learning. To this end, our approach is to apply a sample-efficient model-based reinforcement learning method, so-called PILCO [1], to resolve the high dimensional planning problem of DLO manipulation with a reasonable number of samples. To investigate the effectiveness of our approach, we developed an experimental setup with a dual-arm industrial robot and multiple sensors. Then, we conducted experiments to show that our approach is efficient by performing a DLO manipulation task.
Harcombe, DM, Ruppert, MG, Ragazzon, MRP & Fleming, AJ 1970, 'Higher-harmonic AFM imaging with a high-bandwidth multifrequency Lyapunov filter', 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), IEEE.
View/Download from: Publisher's site
Hayati, H, Eager, D, Brown, T & Jusufi, A 1970, 'STRIDE LENGTH AS A SPEED INDICATOR IN FAST QUADRUPEDS', International Society of Biomechanics, International Society of Biomechanics, Brisbane, Australia.
Hayati, H, Eager, D, Jusufi, A & Brown, T 1970, 'A NOVEL APPROACH TO ANALYZING RAPID TETRAPOD LOCOMOTION USING INERTIAL MEASUREMENT UNITS', International Society of Biomechanics, International Society of Biomechanics, Brisbane, Australia.
View description>>
Rapid quadrupedal movement on granular media and other irregular terrain is an interesting area of research which is under-explored. Current methods of studying rapid quadrupedal movement involve the measurement of ground reaction forces (GRF) using a force plate and a simultaneous kinematics analysis by a High Frame Rate video (HFR). Although force plates provides highly accurate kinetic data, it is not always practical to deploy in the study of animal locomotion. For instance, it is often not possible to embed force plates in irregular terrains [1] characteristic of most ecologically relevant animals’ natural habitats [2]. An alternative method is to utilize an inertial measurement unit (IMU) equipped with a tri-axial accelerometer to analyze accelerations associated with different quadruped gaits. In this study, a tri-axial accelerometer is used to analyze sprinting locomotion dynamics of a greyhound in a simulated racing condition. Kinematics data from videography of the entire race was recorded in each trial for data calibration. In addition, the paw prints of the greyhound on a sandy-loam surface of a race track are also analyzed to sync acceleration data with each individual paw print.
Hayati, H, Eager, D, Jusufi, A & Brown, T 1970, 'A Study of Rapid Tetrapod Running and Turning Dynamics Utilizing Inertial Measurement Units in Greyhound Sprinting', Volume 3: 19th International Conference on Advanced Vehicle Technologies; 14th International Conference on Design Education; 10th Frontiers in Biomedical Devices, ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, American Society of Mechanical Engineers, Cleveland, Ohio, USA, pp. 1-5.
View/Download from: Publisher's site
View description>>
Understanding the biomechanics of rapid running locomotion plays an important role in comparative biomechanics and bio-inspired engineering and is an integral part of animal welfare. However, this is not easily achieved using conventional methods of gait analysis: measuring ground reaction forces using a force plate, mainly on irregular granular terrain i.e. greyhounds in racing conditions or in animal’s natural habitats i.e. cheetahs in natural terrain. An alternative to measuring forces externally via force platforms embedded in track ways, we can attach inertial measurement units to agile quadrupeds to measure the effects of rapid running and turning. Here we deployed an IMU equipped with a tri-axial accelerometer on sprinting greyhounds to analyze rapid locomotion behaviors like dynamic banking and turning in conditions equivalent to racing. High speed videography and paw print analysis of the entire race were used for calibration. The results are beneficial in locomotion analysis and welfare of greyhounds.
Hayati, H, Eager, D, Stephenson, R, Brown, T & Arnott, E 1970, 'The impact of track related parameters on catastrophic injury rate of racing greyhounds', 9th Australasian Congress on Applied Mechanics, ACAM 2017, Australasian Congress on Applied Mechanics, Engineers Australia, Sydney, Australia.
View description>>
Greyhounds can travel twice as fast as human athletes, attaining constant average running speeds of ~65 km/h vs ~29 km/h. Their locomotion is also different from human sprinters, and more similar to cyclists. Unlike human sprinters where the muscles powering the locomotion are also supporting the weight, locomotion of greyhound are powered by torque about the hip. Agile, high-speed quadrupeds, such as the greyhound, experience extreme ground-limb contact forces while negotiating turns; leading to an increased susceptibility to injuries. Added to this, rapid, high velocity changes in direction and extreme turning angles magnify the lateral acceleration forces experienced on the limbs and torso. In this paper, the rate of severe musculoskeletal injuries of racing greyhounds at 34 tracks in New South Wales, Australia, were obtained for the year of 2016. The correlation of parameters, namely bend radius, bend camber, bend length and back straight length and the catastrophic injury rate are statistically analyzed . Track injury locations were obtained from race video footage No correlation was seen between catastrophic injury rate and bend radius, bend camber, bend length and back straight length. Analyses revealed the highest injury rate based on location to be at the first turn. Footage lends support to this being caused by the immediate clustering of the greyhounds towards the inner ‘lure’ rail.” The results of this study support previous findings that greyhounds racing in an anti-clockwise direction most commonly suffer musculoskeletal injuries to their right hind limbs which is consistent with knowledge of the forces that occur on the leading limbs of these dogs as they maintain their speed around bends.
Islam, MS, Saha, SC, Sauret, E, Gu, YT & Molla, MM 1970, 'Numerical investigation of diesel exhaust particle transport and deposition in the CT-scan based lung airway', AIP Conference Proceedings, 7TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING, Author(s), Dhaka, Bangladesh.
View/Download from: Publisher's site
View description>>
© 2017 Author(s). Diesel exhaust particulates matter (DEPM) is a compound mixture of gasses and fine particles that contain more than 40 toxic air pollutants including benzene, formaldehyde, and nitrogen oxides. Exposure of DEPM to human lung airway during respiratory inhalation causes severe health hazards like diverse pulmonary diseases. This paper studies the DEPM transport and deposition in upper three generations of the realistic lung airways. A 3-D digital airway bifurcation model is constructed from the computerized tomography (CT) scan data of a healthy adult man. The Euler-Lagrange approach is used to solve the continuum and disperse phases of the calculation. Local averaged Navier-Stokes equations are solved to calculate the transport of the continuum phase. Lagrangian based Discrete Phase Model (DPM) is used to investigate the particle transport and deposition in the current anatomical model. The effects of size specific monodispersed particles on deposition are extensively investigated during different breathing pattern. The numerical results illustrate that particle diameter and breathing pattern have a substantial impact on particles transport and deposition in the tracheobronchial airways. The present realistic bifurcation model also depicts a new deposition hot spot which could advance the understanding of the therapeutic drug delivery system to the specific position of the respiratory airways.
Jusufi, A, Hayati, HH, Eager, DE & Tucker, BT 1970, 'Exploration of Rapid Sprinting Dynamics of Tetrapod utilizing IMUs', The 8th International Symposium on Adaptive Motion of Animals and Machines (AMAM 2017) Japan, The 8th International Symposium on Adaptive Motion of Animals and Machines (AMAM 2017) Japan.
Karimi, M, Croaker, P, Skvortsov, A & Kessissoglou, N 1970, 'Computation of flow-generated sound of a flat plate using a hybrid RANS-BEM technique', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, 46th International Congress and Exposition on Noise Control Engineering, Hong Kong, China.
View description>>
A hybrid computational fluid dynamics - boundary element method (BEM) technique is used to predict the self-noise generated by a flat plate immersed in low Mach number flow. Reynolds-Averaged Navier-Stokes equations are used to estimate the turbulent boundary layer parameters such as convective velocity, boundary layer thickness and wall shear stress over the surface of the flat plate. The spectrum of the wall pressure fluctuations is evaluated from the turbulent boundary layer parameters and by using semi-empirical models. The cross spectrum density function of turbulent boundary layer pressure is represented as the result of a combination of uncorrelated wall pressure plane waves. An acoustic BEM solver is then used to compute acoustic pressure scattered by the flat plate from the synthesised wall pressure field corresponding to each realisation of uncorrelated wall plane waves. Finally, the acoustic response of the plate subject to turbulent boundary layer excitation is obtained by an ensemble average of the different realisations. The results from the hybrid technique are presented for turbulent flow past a flat plate, with Reynolds number based on chord Rec =4:9x105. The computed aeroacoustic results are compared with experimental data from literature.
Khonasty, R, Carmichael, MG, Liu, D & Aldini, S 1970, 'Effect of external force and bimanual operation on upper limb pose during human-robot collaboration', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney Australia, pp. 81-89.
View description>>
During physical Human-Robot Interaction (pHRI) in industrial applications such as human-robot collaborative abrasive blasting, the operator often interacts with the robot using two hands, exchanging forces through handle bars. For the robot to provide appropriate assistance to the operator and for safe interaction, it would be benefficial for the robot to know the pose of the user. This problem is often challenging due to environmental factors, limited sensing capability in the environment and the robot, and redundancy of the human upper-limb. This paper presents experimental study on how two-hand interaction and force exchange affect the operators upper-limb pose, which can be characterized by swivel angle. The poses of ten subjects were recorded as they interacted with a collaborative robot. Differences in the adopted upper limb pose were analyzed with respect to factors such as unimanual versus bimanual operation, and the amplitude of interaction force between an operator and the robot. The results discovered that the the effect of bimanual operation on the upper limb pose differs between individuals and the magnitude of the force had a varying effect on the pose. The requirement of applying a force forward produced an overall lower swivel angle.
Khonasty, R, Carmichael, MG, Liu, D & Waldron, KJ 1970, 'Upper body pose estimation utilizing kinematic constraints from physical human-robot interaction', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney Australia, pp. 90-99.
View description>>
In physical Human-Robot Interaction (pHRI), knowing the pose of the operator is beneficial and may allow the robot to better accommodate the human operator. Due to a large redundancy in the human body, determining the pose of the human operator is difficult to achieve in unstructured environments especially in human-robot collaborative operations where the robot often occludes the human from vision-based sensors. This work presents an upper body pose estimation method based on exploiting known positions of the human operator's hands while performing a task with the robot. Upper body pose is estimated using upper limb kinematic models alongside sensor information and model approximations to produce solutions that are biomechanically feasible. The pose estimation method was compared to upper body poses obtained using a motion capture system. It was shown to be able to perform robustly with varying amounts of available information. This approach is well suited in applications where robots are controlled using well-defined interfaces such as handlebars, operating in unstructured environments.
Kirby, R, Duan, W, Karimi, M, Brennan, M & Kessissoglou, N 1970, 'Detecting sound waves generated by leaks in buried water distribution pipes', Proceedings of ACOUSTICS 2017 Perth: Sound, Science and Society - 2017 Annual Conference of the Australian Acoustical Society, AAS 2017.
View description>>
It is common to use guided sound waves to detect leaks or cracks in pipelines. Applications include the nondestructive testing of oil and gas pipelines, which normally takes places at ultrasonic frequencies, as well as the detection of leaks and ruptures in water filled pipes at much lower audio frequencies. However, if the pipe is buried then sound leaks out of the pipe into the surrounding medium and this lowers the acoustic energy travelling along the pipe wall. This has the potential to limit the applications of this technology, and so it is necessary to develop knowledge of the acoustic properties of the guided waves in order to optimise detection techniques. Accordingly, this work examines the properties of sound waves propagating in an infinitely long fluid-filled buried pipe, with application to leak detection at low audio frequencies. A parametric study is undertaken to examine the sensitivity of sound propagation to the properties of the internal liquid, pipe walls and of the surrounding medium.
Kodagoda, S 1970, 'Keynote speech: Infrastructure robotics: A better way ofmanaging old infrastructure', 2017 6th National Conference on Technology and Management (NCTM), 2017 6th National Conference on Technology and Management (NCTM), IEEE.
View/Download from: Publisher's site
Kraetzig, O & Sick, N 1970, 'A patent-based approach for the identification of technology strategies - The case of emerging battery technologies', PICMET’17 'Technology Management for the Interconnected World', Portland, Oregon, USA.
Kraetzig, O & Sick, N 1970, 'Overcoming the barrier of non-willingness towards technology commercialization – The case of German battery research', The XXVIII ISPIM conference “Composing the innovation symphony”, Vienna, Austria.
Kratzig, O & Sick, N 1970, 'A Patent-Based Approach for the Identification of Strategic Reactions to Technological Change: The Case of Emerging Battery Technologies', 2017 Portland International Conference on Management of Engineering and Technology (PICMET), 2017 Portland International Conference on Management of Engineering and Technology (PICMET), IEEE, Melbourne, VIC, Australia, pp. 1-10.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Assessments regarding the strategic reactions of companies towards technological change are highly complex and often lack generalization. Methods for analyzing company resources were rather applied than methods directly focusing on the respective strategic reactions. There is, however, a need for a methodology that provides a more comprehensive overview and enables an early recognition of strategic reactions to technological change, for example through the use of easily available secondary data. Thus, the aim of our study is the development of a patent-based approach to identify particular strategic reactions of respective companies towards technological change. Achieving this objective involves an analysis of patent activities for the case of relevant cell manufacturing companies of lithium-ion and post-lithium-ion battery technologies. The developed methodological approach could be applied successfully to the identification of strategic reactions in the battery field. From a practical point of view, our findings give detailed and above all early insights in strategic decisions and enable technology managers to better assess investment options in different technologies.
Lattouf, D & Huynh, BP 1970, 'Flow Across a Butterfly Valve in a Dam Penstock', Volume 7: Fluids Engineering, ASME 2017 International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Tampa, Florida, USA, pp. 1-10.
View/Download from: Publisher's site
View description>>
Butterfly valves are typically used as emergency closure devices in dam penstocks; these valves must be capable of closing if a penstock bursts. This paper summarizes a 3D CFD (Computational Fluid Dynamics) study that was conducted on the water flow across a sizable butterfly valve (1.6m in diameter) in a dam penstock with 57m of water head. The main aim is to determine the maximum torque required to close the valve. Thus semi steady flow conditions across the valve at various degrees of closure were investigated and the corresponding torque calculated. A maximum torque of about 87 700 N-m has been obtained, occurring at valve angle 40° (with valve totally closed at 0°, and fully open at 90°). Visual results were analyzed at each valve angle to understand the nature of the flow through the butterfly valve using various 2D contours and streamline images. The CFD software ANSYS Fluent has been used employing a Finite Volume Method. The RANS (Reynolds-Averaged Navier-Stokes) approach with Realizable K-epsilon turbulence model was employed. A grid independence study with up to 10 million cells has also been carried out, resulting in the adoption of 7.5 million cells in all models. Comparison with other available data was also completed, adding to the reliability of the computational results. Distribution of pressure, flow velocity, and turbulence parameters are also presented.
Lee, JJH, Yoo, C, Hall, R, Anstee, S & Fitch, R 1970, 'Energy-optimal kinodynamic planning for underwater gliders in flow fields', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney, Australia, pp. 42-51.
View description>>
We consider energy-optimal navigation planning in ow fields, which is a long-standing optimisation problem with no known analytical solution. Using the motivating example of an underwater glider subject to ocean currents, we present an asymptotically optimal planning framework that considers realistic vehicle dynamics and provably returns an optimal solution in the limit. One key idea that we introduce is to reformulate the dynamic control problem as a kinematic problem with trim states, which encapsulate the dynamics over suitably long distances. We report simulation examples that, surprisingly, contravene the use of regular 'sawtooth' paths currently in widespread use. We show that, when internal control mechanics are taken into account, energy-efficient paths do not necessarily follow a regular up-and-down pattern. Our work represents a principled planning framework for underwater gliders that will enable improved navigation capability for both commercial and defence applications.
Leighton, B, Zhao, L, Huang, S & Dissanayake, G 1970, 'Extending parallax parameterised bundle adjustment to stereo', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, University of Technology, Sydney, pp. 194-202.
View description>>
The main contribution of this paper is the extension of the ParllaxBA algorithm proposed by [Zhao et al., 2015] into stereo. Simulated and experimental datasets are used to evaluate Cartesian and parallax angle parameterisation for stereo bundle adjustment. It is demonstrated that, like monocular ParallaxBA, under normal conditions the two algorithms perform similarly. However, when the parallax angle of landmarks is low, parallax parameterisation can converge to a lower cost and in less time than the traditional Cartesian parameterisation.
Li, B, Fan, X, Zhang, J, Wang, Y, Chen, F, Kodagoda, S, Wells, T, Vorreiter, L, Vitanage, D, Iori, G, Cunningham, D & Chen, T 1970, 'Predictive Analytics Toolkit for H2S Estimation and Sewer Corrosion', OZWater, OZWater, Australian Water Association, Sydney.
View description>>
This paper presents a predictive analytics toolkit, which is based on the emerging spatiotemporal data analysis techniques, for the estimation of hydrogen sulphide (H2S) gas distribution and prediction of sewer concrete corrosion level. The toolkit is an easy-to-use desktop application with a user-friendly interface for querying and producing output results on GIS. The inputs to the toolkit are the sewer network geometry, monitored factors, and hydraulic information; the outputs of the toolkit are spatiotemporal estimates of H2S gas concentration and concrete corrosion levels on the entire sewer network with uncertainties of the predictions. The toolkit is also able to integrate experts’ domain knowledge or existing physical model’s results as prior knowledge into the analytics model. The final outcomes of the toolkit can be used to prioritise high risk areas, recommend chemical dosing locations, and suggest deployment of sensors. A simulation of H2S and corrosion level prediction on a subsystem of the sewer network in the greater Sydney area is reported to demonstrate the capability of the toolkit
Liao, Y, Huang, L, Wang, Y, Kodagoda, S, Yu, Y & Liu, Y 1970, 'Parse geometry from a line: Monocular depth estimation with partial laser observation', 2017 IEEE International Conference on Robotics and Automation (ICRA), 2017 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Singapore, pp. 5059-5066.
View/Download from: Publisher's site
View description>>
Many standard robotic platforms are equipped
with at least a fixed 2D laser range finder and a monocular camera.
Although those platforms do not have sensors for 3D depth
sensing capability, knowledge of full geometry is an essential
part in many robotics activities. Therefore, recently, there is an
increasing interest in depth estimation using monocular images,
of which the estimated depth might be unreliable in robotics
applications as this task is inherently ambiguous. In this paper,
we have attempted to improve the precision of monocular
depth estimation by introducing 2D planar observation from the
remaining laser range finder without extra cost. Specifically, we
construct a dense reference map from the sparse laser range
data, redefining the depth estimation task as estimating the
distance between the real and the reference depth. To solve
the problem, we construct a novel residual of residual neural
network, and tightly combine the classification and regression
losses for continuous depth estimation. Experimental results
suggest that our method achieves considerable promotion compared
to the state-of-the-art methods on both NYUD2 and
KITTI, validating the effectiveness of our method on leveraging
the additional sensory information. We further demonstrate the
potential usage of our method in obstacle avoidance where
our methodology provides comprehensive depth information
compared to the solution using monocular camera or 2D laser
range finder alone.
Liu, L, Wang, Y, Zhao, L & Huang, S 1970, 'Evaluation of different SLAM algorithms using Google tangle data', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia., pp. 1954-1959.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. In this paper, we evaluate three state-of-the-art Simultaneous Localization and Mapping (SLAM) methods using data extracted from a state-of-the-art device for indoor navigation - the Google Tango tablet. The SLAM algorithms we investigated include Preintegration Visual Inertial Navigation System (VINS), ParallaxBA and ORB-SLAM. We first describe the detailed process of obtaining synchronized IMU and image data from the Google Tango device, then we present some of the SLAM results obtained using the three different SLAM algorithms, all with the datasets collected from Tango. These SLAM results are compared with that obtained from Tango's inbuilt motion tracking system. The advantages and failure modes of the different SLAM algorithms are analysed and illustrated thereafter. The evaluation results presented in this paper are expected to provide some guidance on further development of more robust SLAM algorithms for robotic applications.
Lu, W & Liu, D 1970, 'Active task design in adaptive control of redundant robotic systems', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Sydney Australia, pp. 8-15.
View description>>
This paper seeks to use robots' kinematic redundancy to excite the system persistently, through actively designing a secondary task in the null space of a primary task. Resulted convergence of unknown parameters in adaptive control leads to better system stability and performance. A measure in Grassmannian, referred to as Subspace Discrepancy Measure (SDM), is proposed for evaluating the additional benefit from the secondary task in converging unknown parameters to their true values. This measure evaluates the angles among subspaces that the parameter estimations are converging to, given different secondary tasks. The subspaces are obtained from Principal Component Analysis (PCA) on a small amount of samples of parameter estimations. The SDM is used to determine the choice of the secondary task online through a trial-and-evaluation procedure actively. Numerical simulations demonstrated that the secondary task chosen by SDM enhances the parameter convergence.
Lv, J, Wang, Y, Wu, K, Dissanayake, G, Kobayashi, Y & Xiong, R 1970, 'Planar scan matching using incident angle', 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Vancouver, CANADA, pp. 4049-4056.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. The main contribution of this paper is a planar scan matching algorithm that makes use of the incident angle of a scan point as a feature to enhance the robustness to large relative transformations, particularly in orientation. A new definition of the incident angle is introduced and its consistency with respect to relative transformation between scans is demonstrated. A method that uses the Radial distance and Incident Angle (RIA) for scan alignment, that can efficiently estimate the relative transformation between two scans, is proposed. This approach is designed as a preprocessor for fine scan matching and it is able to pre-align scans that have large angular but limited translational displacement. Scans collected with aggressive robot motion in two typical indoor environments as well as benchmark datasets, are used to demonstrate the effectiveness of RIA when compared with a range of scan matching algorithms reported in the literature.
Maroufi, M, Ruppert, MG, Fowler, AG & Moheimani, SOR 1970, 'Design and control of a single-chip SOI-MEMS atomic force microscope', 2017 American Control Conference (ACC), 2017 American Control Conference (ACC), IEEE.
View/Download from: Publisher's site
Moore, SI, Ruppert, MG & Yong, YK 1970, 'Design and analysis of piezoelectric cantilevers with enhanced higher eigenmodes for atomic force microscopy', 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), IEEE.
View/Download from: Publisher's site
Munoz, F, Miro, JV, Dissanayake, G, Ulapane, N & Nguyen, L 1970, 'Design of a lock-in amplifier integrated with a coil system for eddy-current non-destructive inspection', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1948-1953.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Eddy-current non-destructive inspections of conductive components are of great interest in several industries including civil infrastructure and the mining industry. In this work, we have used a driver-pickup coil system as the probe to carry out inspection of ferromagnetic plates. The specific geometric configuration of the probe generates weak electric signals that are buried in a noisy environment. In order to detect these weak signals, we have designed and implemented a lock-in amplifier as part of the signal processing technique to increase the signal-to-noise ratio and also improve the sensitivity of the probe. We have used Comsol as a finite element method (FEM) to design the probe and conducted experiments with the probe and the lock-in amplifier. The experimental results, which are in agreement with the FEM results, indicate that the designed probe along with a lock-in amplifier can potentially be used to estimate the thickness of thin plates.
Nguyen, K-D & Liu, D 1970, 'Robust control of a brachiating robot', 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Vancouver Canada, pp. 6555-6560.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. This paper investigates the robust control of an underactuated brachiating robot. Inspired by the pendulumlike movements in gibbons' arboreal locomotion, the controllers are designed to synchronize the brachiator with a virtual oscillator. Two schemes are proposed: a model-dependent feedback linearization scheme and a sliding-mode scheme that is independent of the system model. The simulation results illustrate that the proposed schemes are robust to the arbitrary initial configurations of the brachiator and the limitation in the motor torque at the elbow joint. Furthermore, both controllers enable the underactuated robot to brachiate along a structural member with an upward slope.
Nguyen, L, Ulapane, N, Miro, JV, Dissanayake, G & Munoz, F 1970, 'Improved signal interpretation for cast iron thickness assessment based on pulsed eddy current sensing', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 2005-2010.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. This paper presents a novel signal processing approach for computing thickness of ferromagnetic cast iron material, widely employed in older infrastructure such as water mains or bridges. Measurements are gathered from a Pulsed Eddy Current (PEC) based sensor placed on top of the material, with unknown lift-off, as commonly used during non-destructive testing (NDT). The approach takes advantage of an analytical logarithmic model proposed in the literature for the decaying voltage induced at the PEC sensor pick-up coil. An increasingly more accurate and robust algorithm is proven here by means of an Adaptive Least Square Fitting Line (ALSFL) recursive strategy, suitable to recognize the most linear part of the sensor's logarithmic output voltage for subsequent gradient computation, from which thickness is then derived. Moreover, efficiency is also gained as processing can be carried out on only one decaying voltage signal, unlike averaging over multiple measurements as is usually done in the literature. Importantly, the new signal processing methodology demonstrates highest accuracies at the lower thicknesses, a circumstance most relevant to NDT evaluation. Experiments that verify the proposed method in real-world thickness assessment of cast iron material are presented and compared with current practices, showing promising results.
Parnell, J & Hartcher, A 1970, 'Setting noise objectives for outdoor events at the Sydney Opera House', Proceedings of ACOUSTICS 2017 Perth: Sound, Science and Society - 2017 Annual Conference of the Australian Acoustical Society, AAS 2017.
View description>>
Unwanted music from outdoor events is considered a form of noise pollution which presents a unique set of challenges for regulators when compared to other environmental noise sources. Unlike noise generated by sources such as transport or industry where lower levels are always desirable, there is a minimum level of music below which patron experience will be unacceptable. The challenge for regulators therefore lies in balancing the need for entertainment against the impacts of outdoor music on the surrounding population. Regulators and venue operators of outdoor music events in urban environments are also often required to comply with receiver based noise limits in noise catchments complicated by high levels of extraneous noise from ferries, trains, traffic, pedestrians, restaurants and the like. With this in mind, this paper describes the approach undertaken to review and contemporise the noise criteria for outdoor events held on the steps and forecourt of the Sydney Opera House by adopting Front of House (i.e. at the source) limits rather than receiver based noise objectives.
Peng, J, Kessissoglou, N & Parnell, J 1970, 'Evaluation of calculation of road traffic noise in Australia', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet.
View description>>
Noise prediction for the assessment of operational road traffic noise impact in Australia has been made largely using United Kingdom's Calculation of Road Traffic Noise (CoRTN), initially published in 1975, with a number of crude adjustments to suit Australian conditions. Since the majority of the noise measurements forming the data used to develop CoRTN was taken prior to 1973 and the Australian adjustments were derived in 1983, the noise prediction accuracy has reduced over the years as considerable changes have taken place not only in the design of vehicles and motor vehicle noise regulation, but also in the variety of vehicles and the increased presence of larger trucks on the Australian road network. In this present study, the prediction performance of CoRTN under Australian conditions was examined using statistical and sensitivity analyses. The statistical analysis demonstrates that the Australian adjustments are no longer suitable and identifies the presence of heavy vehicles as being the primary influence on the performance of CoRTN with temperature having a secondary, but notable effect. A subsequent sensitivity analysis is presented and shows that the ability for CoRTN to predict daytime and night-Time noise levels accurately is highly sensitive to the mix of heavy vehicles, and temperature to a lesser extent. Some modifications to current modelling practice are introduced, although results demonstrate that current practice is over simplistic.
Perera, A, Arukgoda, J, Ranasinghe, R & Dissanayake, G 1970, 'Localization system for carers to track elderly people in visits to a crowded shopping mall', 2017 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 2017 International Conference on Indoor Positioning and Indoor Navigation (IPIN), IEEE, Sapporo, Japan, pp. 1-8.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. This work presents a real-time localization system developed for professional care givers to track residents of an aged care facility during their visits to a crowded, multi-story shopping mall. The proposed system consists of a Wi-Fi based self-localization platform integrated into a wheeled walking frame and an application installed in a hand-held tablet device for displaying the locations of walker users. The density of people in the shopping mall changes significantly during the day thus the expected Wi-Fi signal strength at a given location is subject to large variations. However, Identifying the location to be within a given area is adequate and the average speed of motion is less than 0.5 m/sec. In this paper, an algorithm that addresses these unique requirements is presented. We exploit the signal strength characteristics of existing Wi-Fi network and prior knowledge of the building floor plans for developing our core algorithm. The environments is divided in to cells that are either enclosed spaces or divisions of larger open regions. The probability density function of the Wi-Fi signal strength of each cell is estimated using Kernel Density Estimation (KDE) and is used in a probabilistic framework to estimate the user location. Motion model of the users as well as the detection of floor transition events are used to enhance the performance of the location estimator. The algorithm was implemented using an Odroid-C1 computer and a tablet with Android operating system. Results obtained during field trials at Roselands Shopping Mall in Sydney are presented.
Perera, A, Ranasinghe, R & Dissanayake, G 1970, 'A neural network based place recognition technique for a crowded indoor environment', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1937-1942.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Place recognition in a crowded and cluttered environment is a challenging task due to its dynamic characteristics such as moving obstacles, varying lighting conditions and occlusions. This work presents a robust place recognition technique that could be applied into a similar environment, by combining well known Bag of Words technique with a feedforward neural network. The feedforward neural network we use have three layers with a single hidden layer and it relies on rectifier and softmax activation functions. We employ cross entropy function to model the cost of our neural network and utilize Adam algorithm for minimizing this cost at the training phase. The output layer with softmax activation in the neural network, produces a vector of probabilities which represent the likelihood of test image being captured from a given region. These values are further improved by incorporating a transition matrix which is based on the building layout. We have evaluated our neural network based place recognition technique with data collected from a crowded indoor shopping mall and promising results have been observed by this approach. We also have analyzed the behavior of neural network for changes in hyper-parameters and presented the results.
Popovic, M, Vidal-Calleja, T, Hitz, G, Sa, I, Siegwart, R & Nieto, J 1970, 'Multiresolution mapping and informative path planning for UAV-based terrain monitoring', 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Vancouver, Canada, pp. 1382-1388.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Unmanned aerial vehicles (UAVs) can offer timely and cost-effective delivery of high-quality sensing data. However, deciding when and where to take measurements in complex environments remains an open challenge. To address this issue, we introduce a new multiresolution mapping approach for informative path planning in terrain monitoring using UAVs. Our strategy exploits the spatial correlation encoded in a Gaussian Process model as a prior for Bayesian data fusion with probabilistic sensors. This allows us to incorporate altitude-dependent sensor models for aerial imaging and perform constant-time measurement updates. The resulting maps are used to plan information-rich trajectories in continuous 3-D space through a combination of grid search and evolutionary optimization. We evaluate our framework on the application of agricultural biomass monitoring. Extensive simulations show that our planner performs better than existing methods, with mean error reductions of up to 45% compared to traditional 'lawnmower' coverage. We demonstrate proof of concept using a multirotor to map color in different environments.
Ranasinghe, R, Dissanayake, G, Furukawa, T, Arukgoda, J & Dantanarayana, L 1970, 'Environment representation for mobile robot localisation', 2017 IEEE International Conference on Industrial and Information Systems (ICIIS), 2017 IEEE International Conference on Industrial and Information Systems (ICIIS), IEEE, Peradeniya, Sri Lanka, pp. 1-6.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. An adequate representation of the environment is an essential component of a mobile robot navigation system. This paper reviews the techniques reported in the literature for capturing the geometry of the space surrounding a mobile robot. In particular, the use of distance functions that combine some of the advantages of feature based and occupancy grid based representations for mobile robot localisation is described in detail. The effectiveness of various distance function based representations is demonstrated using a number of practical examples for localising ground and air vehicles.
Roser, C, Lorentzen, K, Lenze, D, Deuse, J, Klenner, F, Richter, R, Schmitt, J & Willats, P 1970, 'Bottleneck Prediction Using the Active Period Method in Combination with Buffer Inventories', IFIP Advances in Information and Communication Technology, Springer International Publishing, pp. 374-381.
View/Download from: Publisher's site
View description>>
© 2017, IFIP International Federation for Information Processing. Knowing the bottleneck is one of the keys to improving a production system. The active period method is one approach to detect shifting bottlenecks that most other bottleneck detection methods have problems with. Yet, like many other methods, these detections are limited to detecting the past and present bottlenecks. In this paper, we combined the active period method with the buffer inventories and free buffer spaces of the adjacent inventories to statistically predict not only an upcoming change of the bottleneck, but also where the bottleneck will move to.
Ruppert, MG, Harcombe, DM, Ragazzon, MRP, Moheimani, SOR & Fleming, AJ 1970, 'Frequency domain analysis of robust demodulators for high-speed atomic force microscopy', 2017 American Control Conference (ACC), 2017 American Control Conference (ACC), IEEE.
View/Download from: Publisher's site
Shakor, P, Renneberg, J, Nejadi, S & Paul, G 1970, 'Optimisation of Different Concrete Mix Designs for 3D Printing by Utilizing 6DOF Industrial Robot', Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC), 34th International Symposium on Automation and Robotics in Construction, Tribun EU, s.r.o., Brno, Taipei, Taiwan, pp. 268-275.
View/Download from: Publisher's site
View description>>
Additive Manufacturing (AM) technologies are becoming increasingly viable for commercial and research implementation into various applications. AM refers to the process of forming structures layer upon layer and finds application in prototyping and manufacturing for building construction. It has recently begun to be considered as a viable and attractive alternative in certain circumstances in the construction industry. This paper focuses on the utilisation of different concrete mixtures paired with extrusion techniques facilitated by a six Degree of Freedom (DOF) industrial robot. Using methods of Damp Least Squares (DLS) in conjunction with Resolved Motion Rate Control (RMRC), it is possible to plan stable transitions between several waypoints representing the various print cross-sections. Calculated paths are projected via 'spline' interpolation into the manipulator controlled by custom software. This article demonstrates the properties of different concrete mixture designs, showing their performance when used as a filament in 3D Printing and representing a comparison of the results that were found. In this study, the prepared materials consist of ordinary Portland cement, fine sand between (425-450) micron, coarse aggregate ranges (3) mm and chemical admixtures which have been used to accelerate setting times and reduce water content. Numerous tests were performed to check the buildability, flowability, extrudability and moldability of the concrete mixtures. The horizontal test was used to determine the flowability and consistency, while the vertical and squeeze-flow tests were used to determine the buildability of the layers. The extrudability and moldability of the concrete mixtures were controlled by the robot and associated extruder speeds.
Shi, L, Valls Miro, J, Vidal Calleja, T, Vitanage, D & Rajalingam, J 1970, 'Innovative Data-driven “along-the-pipe” Condition Assessment for Critical Water Mains', OZWATER’17 Australia’s International Water Conference & Exhibition, OzWater’17 Australia’s International Water Conference & Exhibition, Australian Water Association, Sydney, pp. 1-8.
View description>>
Recent research findings on remaining life prediction for older Cast Iron critical water mains suggest increasing reliability by calculating stress concentration factors from the corrosion patch geometries expected to be present in the asset, not just extreme pitting as is generally carried out within the industry. This study proposes an innovative data-driven “along-the-pipe” framework able to utilise local inspection results further by capturing data correlations present in the remaining wall thickness measurement. This knowledge can in turn be utilised to produce estimates for “along-the-pipe” patch geometry predictions, hence remaining life. Results from inspections in a real pipeline in the Sydney Water network are compared to conventional Extreme Value Analysis (EVA) to validate the improvements of the proposed strategy.
Shiozaki, T & Dissanayake, G 1970, 'Monocular 3D metric scale reconstruction using depth from defocus and image velocity', 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Vancouver, pp. 6723-6728.
View/Download from: Publisher's site
View description>>
This paper presents a novel approach to metric scale reconstruction of a three-dimensional (3D) scene using a monocular camera. Using a sequence of images from a monocular camera with a fixed focus lens, metric distance to a set of features in the environment is estimated from image blur due to defocus. The blur texture ambiguity which causes scale errors in depth from defocus is corrected in an EKF framework that exploits image velocity measurements. We show in real experiments that our method converges to a metric scale, accurate, sparse depth map and 3D camera poses with images from a monocular camera. Therefore, the proposed approach has the potential to enhance robot navigation algorithms that rely on monocular cameras.
Sick, N, Broering, S, Aaldering, L & Figgemeier, E 1970, 'Life cycle patterns and industry clockspeed in energy storage', The XXVIII ISPIM conference “Composing the innovation symphony”, Vienna, Austria.
Sick, N, Guertler, MR & Kriz, A 1970, 'Wicked Problem Sprint Sessions as a Means of Open Innovation – Development and Evaluation at ISPIM Events', The ISPIM Innovation Summit – Building the Innovation Century, Melbourne, pp. 1-15.
View description>>
The world is becoming increasingly complex and interconnected, and so are the challenges we face in innovation management – but do our problem solving methods keep pace to deal with such wicked problems? The present study focuses on developing and evaluating an open innovation method named wicked problem sprint sessions (WPSS) to cope with wicked problems in innovation management. This workshop-based method is embedded in the ISPIM conference context and aims at bringing together interdisciplinary experts from the triple helix. The method uses different creativity, design, cross-industry and gamification elements to allow a quick understanding of a focal problem and development of innovative solution ideas and concepts. The contribution is twofold. Firstly, we provide a concise overview of wicked problems with respect to innovation management, linking the multidisciplinary background of wicked problems to the requirements of innovation management. Secondly, we present and evaluate WPSS as a new open innovation method how to solve wicked problems in innovation management, not only in business but also in educational and public domains.
Song, B, Wang, H, Xiao, W, Huang, S & Shi, L 1970, 'Gaussian process model enabled particle filter for device-free localization', 2017 20th International Conference on Information Fusion (Fusion), 2017 20th International Conference on Information Fusion (Fusion), IEEE, Xi'an, China, pp. 1-7.
View/Download from: Publisher's site
View description>>
© 2017 International Society of Information Fusion (ISIF). Device-free localization (DFL) is an emerging wireless network target localization technique that does not need to attach any electronic device with the target. It is remaining as a challenging research problem due to the weak wireless signals and the uncertain wireless communication environment. In this paper, a novel Gaussian Process (GP) based wireless propagation model is proposed to describe the likelihood relationship between the target location and the changes of the RSS measurement for a wireless link. Sequentially Particle Filter (PF) is applied to the DFL for estimating the location of the target, after the GP model is trained using the experimental measurements of the link. Experimental results demonstrate that the proposed GP-PF algorithm can track the target with much better localization accuracy than the Support Vector Machine (SVM) based PF approach.
Song, B, Wang, H, Xiao, W, Huang, S & Shi, L 1970, 'Gaussian Process Model Enabled Particle Filter for Device-Free Localization', 2017 20TH INTERNATIONAL CONFERENCE ON INFORMATION FUSION (FUSION), 20th International Conference on Information Fusion (Fusion), IEEE, Xian, PEOPLES R CHINA, pp. 1134-1139.
Song, J, wang, J, Zhao, L, Huang, S & Dissanayake, G 1970, 'Deformable Soft-tissue Reconstruction using Stereo Scope for Minimal Invasive Surgery', CARS 2017 -- Computer Assisted Radiology and Surgery, 31st International Congress and Exhibition, CARS 2017 -- Computer Assisted Radiology and Surgery, 31st International Congress and Exhibition.
song, J, wang, J, Zhao, L, huang, S & Dissanayake, G 1970, 'Robust Shape Recovery of Deformable Soft-tissue Based on Information from Stereo Scope for Minimal Invasive Surgery', Hamlyn Symposium on Medical Robotics (HSMR 2017), Hamlyn Symposium on Medical Robotics, Kensington, England.
View description>>
Overcoming small field of view of scopes is an important challenge in minimal invasive surgery (MIS). Efforts have been devoted in 3D soft-tissue construction and camera localization [1-2]. This paper proposes arobust strategy for simultaneous camera localization and dense reconstruction of deformable surfaces. The robustness is achieved by: (1) using a sequence of images collected from a stereoscope by consideringuncertainty map; (2) filtering images with low intensity; (3) filtering depth by normals. Our approach greatly reduces depth estimation parameter adjustment efforts while still generates good results and preservestopological details. Experiments reveal that the proposed approach is convenient for dynamically rebuild and visualize the latest shape of soft-tissue to mitigate unnecessary tissue damages in minimalinvasive surgery.
Su, D, Vidal-Calleja, T & Miro, JV 1970, 'Towards real-time 3D sound sources mapping with linear microphone arrays', 2017 IEEE International Conference on Robotics and Automation (ICRA), 2017 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Singapore, Singapore, pp. 1662-1668.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. In this paper, we present a method for real-time 3D sound sources mapping using an off-the-shelf robotic perception sensor equipped with a linear microphone array. Conventional approaches to map sound sources in 3D scenarios use dedicated 3D microphone arrays, as this type of arrays provide two degrees of freedom (DOF) observations. Our method addresses the problem of 3D sound sources mapping using a linear microphone array, which only provides one DOF observations making the estimation of the sound sources location more challenging. In the proposed method, multi hypotheses tracking is combined with a new sound source parametrisation to provide with a good initial guess for an online optimisation strategy. A joint optimisation is carried out to estimate 6 DOF sensor poses and 3 DOF landmarks together with the sound sources locations. Additionally, a dedicated sensor model is proposed to accurately model the noise of the Direction of Arrival (DOA) observation when using a linear microphone array. Comprehensive simulation and experimental results show the effectiveness of the proposed method. In addition, a real-time implementation of our method has been made available as open source software for the benefit of the community.
Sun, L, Vidal-Calleja, T & Miro, JV 1970, 'Coupling conditionally independent submaps for large-scale 2.5D mapping with Gaussian Markov Random Fields', 2017 IEEE International Conference on Robotics and Automation (ICRA), 2017 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Singapore, Singapore, pp. 3131-3137.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Building large-scale 2.5D maps when spatial correlations are considered can be quite expensive, but there are clear advantages when fusing data. While optimal submapping strategies have been explored previously in covariance-form using Gaussian Process for large-scale mapping, this paper focuses on transferring such concepts into information form. By exploiting the conditional independence property of the Gaussian Markov Random Field (GMRF) models, we propose a submapping approach to build a nearly optimal global 2.5D map. In the proposed approach data is fused by first fitting a GMRF to one sensor dataset; then conditional independent submaps are inferred using this model and updated individually with new data arrives. Finally, the information is propagated from submap to submap to later recover the fully updated map. This is efficiently achieved by exploiting the inherent structure of the GMRF, fusion and propagation all in information form. The key contribution of this paper is the derivation of the algorithm to optimally propagate information through submaps by only updating the common parts between submaps. Our results show the proposed method reduces the computational complexity of the full mapping process while maintaining the accuracy. The performance is evaluated on synthetic data from the Canadian Digital Elevation Data.
Thiyagarajan, K, Kodagoda, S & Van Nguyen, L 1970, 'Predictive analytics for detecting sensor failure using autoregressive integrated moving average model', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1926-1931.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Sensors play a vital role in monitoring the important parameters of critical infrastructure. Failure of such sensors causes destabilization to the entire system. In this regard, this paper proposes a predictive analytics solution for detecting the failure of a sensor that measures surface temperature from an urban sewer. The proposed approach incorporates a forecasting technique based on the past time series of sparse data using an autoregressive integrated moving average (ARIMA) model. Based on the 95% forecast interval and continuity of faulty data, a criterion was set to detect anomalies and to issue a warning for sensor failure. The forecasted and faulty data were assumed Gaussian distributed. By using the probability density of the distribution, the mean and variance were computed for faulty data to examine the abnormality in the variance value of each day to detect the sensor failure. The experimental results on the sewer temperature data are appealing.
Ulapane, N, Nguyen, L, Miro, JV, Alempijevic, A & Dissanayake, G 1970, 'Designing a pulsed eddy current sensing set-up for cast iron thickness assessment', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 901-906.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. Pulsed Eddy Current (PEC) sensors possess proven functionality in measuring ferromagnetic material thickness. However, most commercial PEC service providers as well as researchers have investigated and claim functionality of sensors on homogeneous structural steels (steel grade Q235 for example). In this paper, we present design steps for a PEC sensing set-up to measure thickness of cast iron, which is unlike steel, is a highly inhomogeneous and non-linear ferromagnetic material. The setup includes a PEC sensor, sensor excitation and reception circuits, and a unique signal processing method. The signal processing method yields a signal feature which behaves as a function of thickness. The signal feature has a desirable characteristic of being lowly influenced by lift-off. Experimental results show that the set-up is usable for Non-destructive Evaluation (NDE) applications such as cast iron water pipe assessment.
Unicomb, J, Dantanarayana, L, Arukgoda, J, Ranasinghe, R, Dissanayake, G & Furukawa, T 1970, 'Distance function based 6DOF localization for unmanned aerial vehicles in GPS denied environments.', IROS, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Vancouver, BC, Canada, pp. 5292-5297.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. This paper presents an algorithm for localizing an unmanned aerial vehicle (UAV) in GPS denied environments. Localization is performed with respect to a pre-built map of the environment represented using the distance function of a binary mosaic, avoiding the need for extraction and explicit matching of visual features. Edges extracted from images acquired by an on-board camera are projected to the map to compute an error metric that indicates the misalignment between the predicted and true pose of the UAV. A constrained extended Kalman filter (EKF) framework is used to generate an estimate of the full 6-DOF location of the UAV by enforcing the condition that the distance function values are zero when there is no misalignment. Use of an EKF also makes it possible to seamlessly incorporate information from any other system on the UAV, for example, from its auto-pilot, a height sensor or an optical flow sensor. Experiments using a hexarotor UAV both in a simulation environment and in the field are presented to demonstrate the effectiveness of the proposed algorithm.
Wang, J, Huang, S, Zhao, L, Ge, J, He, S, Zhang, C & Wang, X 1970, 'High quality 3D reconstruction of indoor environments using RGB-D sensors', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1739-1744.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. High-quality 3D reconstruction of large-scale indoor scene is the key to combine Simultaneous Localization And Mapping (SLAM) with other applications, such as building inspection and construction monitoring. However, the requirement of global consistency brings challenges to both localization and mapping. In particular, significant localization and mapping error can happen when standard SLAM techniques are used when dealing with the area of featureless walls and roofs. This paper proposed a novel framework aiming to reconstruct a high-quality, globally consistent 3D model for indoor environments using only a RGB-D sensor. We first introduce the sparse and dense feature constraints in the local bundle adjustment. Then, the planar constraints are incorporated in the global bundle adjustment. We fuse the point clouds in a truncated signed distance function volume, from which the high quality mesh can be extracted. Our framework leads to a comprehensive 3D scanning solution for indoor scene, enabling high-quality results and potential applications in building information system. The video of 3D models reconstructed by the method proposed in this paper is available at https://youtu.be/DWMP4YfeNeY.
Wang, J, Huang, S, Zhao, L, Ge, J, He, S, Zhang, C & Wang, X 1970, 'High Quality 3D Reconstruction of Indoor Finvironments using RGB-D Sensors', PROCEEDINGS OF THE 2017 12TH IEEE CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS (ICIEA), 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, CAMBODIA, Siem Reap, pp. 1739-1744.
Wang, S, Nerse, C & Kim, HW 1970, 'Vibro-Acoustic Noise Analysis of a Washing Machine', Conference Proceedings of the Society for Experimental Mechanics Series, 35th IMAC Conference and Exposition on Structural Dynamics, Springer International Publishing, Garden Grove, CA, pp. 47-53.
View/Download from: Publisher's site
View description>>
This study is a comprehensive effort in analyzing the vibro-acoustic characteristics of a top loaded washing machine, and focuses on the identification of the main noise source. For this purpose, the vibro-acoustic behaviors of components in washing machine are investigated systematically. Modal analysis of the main components in the system (cabinet, tub, and motor) are performed for identification of vibration modes that are related to noise radiation. The cogging torque that is associated with the brushless DC motor is identified with the order analysis. The critical frequency bands are determined with respect to components, and preliminary investigation for the noise source identification is concluded. For a quantitative ranking of contributions from several components to output noise during operation of the washing machine, Operational Transfer Path Analysis method is used. The vibration and acoustic response are measured in a relation to stepwise control of the operation speed of the BLDC motor. Transmissibility functions with respect to transfer paths are calculated, and cross-talk cancellation is applied using principal component analysis. The evaluated synthesized response matched well with the measured noise output through all measurement steps.
Williams, PT, Åbom, M, Kirby, R & Hill, J 1970, 'The influence of higher order incident modes on the performance of a hybrid reactive-dissipative splitter silencer', Proceedings of Meetings on Acoustics, 172nd Meeting of the Acoustical Society of America, Acoustical Society of America, Boston, Massachusetts.
View/Download from: Publisher's site
View description>>
© 2017 Acoustical Society of America. A hybrid reactive-dissipative splitter silencer offers the potential to attenuate turbomachinery noise over a wide frequency range, including the problematic low to medium frequencies. This article uses a theoretical model to investigate the performance of a hybrid parallel baffle silencer for different complex incident sound fields. This includes an incident sound field with equal modal energy density, as well as the excitation of individual higher order modes. It is shown that provided horizontal and vertical partitions are used in the reactive element, the sound attenuation performance of the reactive chamber under complex incident sound fields is equivalent to that obtained using plane wave excitation over the frequency range of interest. Furthermore, it is demonstrated that the reactive elements work at frequencies above the first cut-on mode in the inlet duct, and so they are capable of extending sound attenuation into the low to medium frequency range. This delivers an efficient hybrid silencer design that is suitable for use in power generation applications, such as gas turbine exhaust systems.
Williams, PT, Kirby, R, Hill, J & Åbom, M 1970, 'Circular duct hybrid bar silencer insertion loss measurement with comparison to prediction', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet.
View description>>
Noise within the exhaust of gas turbine systems is commonly reduced using dissipative silencers. These types of silencers provide a high performance across the mid-frequency range but do little to reduce noise at the low frequencies. Reactive solutions are more effective at targeting low frequency noise, however these silencers must be designed without compromising restrictive pressure drop limitations while remaining operational in large diameter ducts and at high temperatures. A hybrid dissipative-reactive silencer is investigated here allowing for both the broadband and tonal low frequency noise to be reduced. The dissipative elements are regular, perforated baffles containing absorbent material and the reactive elements make use of quarter wave resonators. The hybrid design is applied to a circular duct bar silencer cross-section where the addition of the reactive component will have minimal effect on pressure drop. Insertion loss measurements are presented for a dissipative and hybrid silencer and it is found that the reactive elements increase insertion loss at the targeted frequency and at regular frequencies above this. Such increases in performance are found to persist outside of the duct's plane wave region. A two dimensional finite element model is also used to predict silencer transmission loss and this shows good agreement when compared to experimental data. This model may then be used to develop new bespoke hybrid silencer designs for demanding noise control applications.
Wu, K, Li, X, Ranasinghe, R, Dissanayake, G & Liu, Y 1970, 'RISAS: A novel rotation, illumination, scale invariant appearance and shape feature', 2017 IEEE International Conference on Robotics and Automation (ICRA), 2017 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Singapore, Singapore, pp. 4008-4015.
View/Download from: Publisher's site
View description>>
© 2017 IEEE. This paper presents a novel appearance and shape feature, RISAS, which is robust to viewpoint, illumination, scale and rotation variations. RISAS consists of a keypoint detector and a feature descriptor both of which utilise texture and geometric information present in the appearance and shape channels. A novel response function based on the surface normals is used in combination with the Harris corner detector for selecting keypoints in the scene. A strategy that uses the depth information for scale estimation and background elimination is proposed to select the neighbourhood around the keypoints in order to build precise invariant descriptors. Proposed descriptor relies on the ordering of both grayscale intensity and shape information in the neighbourhood. Comprehensive experiments which confirm the effectiveness of the proposed RGB-D feature when compared with CSHOT [1] and LOIND[2] are presented. Furthermore, we highlight the utility of incorporating texture and shape information in the design of both the detector and the descriptor by demonstrating the enhanced performance of CSHOT and LOIND when combined with RISAS detector.
Zainudin, Z, Ibrahim, MM & Kodagoda, S 1970, 'Non-parametric data optimization for 2D laser based people tracking', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia.
View/Download from: Publisher's site
View description>>
Generally, a model on describing human motion patterns should have an ability to enhance tracking performance particularly when dealing with long term occlusions. These patterns can be efficiently learned by applying Gaussian Processes (GPs). However, the GPs can become computationally expensive with increasing training data with time. Thus, with the proposed data selection and management using Mutual Information (MI) and Mahalanobis Distance (MD)approach, we have be able to keep the necessary portion of informative data and discard the others. This approach is then experimented by using the measurements of horizontal 2D scan of public area of our research centre with a stationary laser range finder. Experimental results show that even 90% reduction of data did not contribute to significantly increased Root Mean Square Error (RMSE). Implementation of Gaussian Process - Particle filter tracker for people tracking with long term occlusions produces a remarkable tracking performance when compared to Extended Kalman Filter (EKF) tracker.
Zhang, T, Wu, K, Su, D, Huang, S & Dissanayake, G 1970, 'An Invariant-EKF VINS Algorithm for Improving Consistency', IEEE International Conference on Intelligent Robots and Systems, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Vancouver, Canada, pp. 1578-1585.
View/Download from: Publisher's site
View description>>
The main contribution of this paper is an invariant extended Kalman filter(EKF) for visual inertial navigation systems (VINS). It is demonstrated thatthe conventional EKF based VINS is not invariant under the stochasticunobservable transformation, associated with translations and a rotation aboutthe gravitational direction. This can lead to inconsistent state estimates asthe estimator does not obey a fundamental property of the physical system. Toaddress this issue, we use a novel uncertainty representation to derive a RightInvariant error extended Kalman filter (RIEKF-VINS) that preserves thisinvariance property. RIEKF-VINS is then adapted to the multistate constraintKalman filter framework to obtain a consistent state estimator. Both MonteCarlo simulations and real-world experiments are used to validate the proposedmethod.
Zhang, Z, Oberst, S & Lai, JCS 1970, 'Uncertainty analysis for the prediction of disc brake squeal propensity', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, Internoise 2017, Hong Kong, China.
View description>>
ACT Since brake squeal was first investigated in the 1930s, it has been a noise, vibration and harshness (NVH) problem plaguing the automotive industry due to warranty-related claims and customer dissatisfaction. Accelerating research efforts in the last decade, represented by almost 70% of the papers published in the open literature, have improved the understanding of the generation mechanisms of brake squeal, resulting in better analysis of the problem and better development of countermeasures by combining numerical simulations with noise dynamometer tests. However, it is still a challenge to predict brake squeal propensity with any confidence. This is because of modelling difficulties that include the often transient and nonlinear nature of brake squeal, and uncertainties in material properties, operating conditions (brake pad pressure and temperature, speed), contact conditions between pad and disc, and friction. Although the conventional Complex Eigenvalue Analysis (CEA) method, widely used in industry, is a good linear analysis tool for identifying unstable vibration modes to complement noise dynamometer tests, it is not a predictive tool as it may either over-predict or under-predict the number of unstable vibration modes. In addition, there is no correlation between the magnitude of the positive real part of a complex eigenvalue and the likelihood that the unstable vibration mode will squeal. Transient nonlinear simulations are still computationally too expensive to be implemented in industries for even exploratory predictions. In this paper, a stochastic approach, incorporating uncertainties in the surface roughness of the lining, material properties and the friction coefficient, is applied to predict the squeal propensity of a full disc brake system by using CEA on a finite element model updated by experimental modal testing results. Results compared with noise dynamometer squeal tests illustrate the potential of the stochastic CEA approach ov...
Zhao, S, Cheng, E, Qiu, X, Burnett, I & Liu, CC 1970, 'Simulations on the wind noise reduction by spherical shell windscreens', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet.
View description>>
Various windscreens are widely used in outdoor acoustic measurements to reduce the effect of the wind induced pressure fluctuations at the microphones and to improve the measurement accuracy. However, the physical mechanism of the wind noise reduction by windscreens remains unclear yet. In this paper, the wind noise reduction performance of spherical shell windscreens is investigatedwith numerical simulations based on the turbulent modeling in porous media. The effects of both the diameter and the thickness of the spherical shell windscreen on the wind noise reduction performance are investigatedfor both uniform and turbulent incoming flows. It is found that the wind noise at the microphone can be reduced by spherical shell windscreens only when the thickness of the spherical shell windscreen is smaller than 0.1 cmfor uniformincoming flow, and the wind noise reduction increases with the diameter but approaches a constant when the windscreen is largerthan 20 cm.Forturbulentincoming flow, the wind noise reduction performance of the spherical shell windscreen increases with the diameter and reaches the best when the shell thickness is around 1.0 cm.
Zhao, S, Cheng, E, Qiu, X, Lacey, J & Maisch, S 1970, 'A method of configuring fixed coefficient active noise controllers for traffic noise reduction', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, Hong Kong, China.
View description>>
In practical applications of Active Noise Control (ANC) systems on traffic noise reduction, the noise sources to be controlled are usually far away from the system and are continuously moving, hence there are no fixed noise sources for configuring the controller. This paper proposes a method to configure fixed coefficient ANC systems for the scenario of traffic noise reduction. In the tuning process, a pseudo noise source is proposed to be placed near a single channel ANC system to adjust the controller. After the optimal coefficients of the controller are obtained for this situation, the coefficients are fixed and the ANC system is utilized to cancel the actual noise source in the far-field. Simulation results showed that when the noise source is a point source located very far away from the ANC system, moving the pseudo noise source farther away from the single-channel ANC system can effectively increase the noise reduction. However, if the noise source is closer to the single-channel ANC system than the pseudo noise source, the performance deteriorates quickly. When the primary noise originates from a line array of incoherent point sources far from the ANC system, moving the pseudo noise source farther away from the system can effectively increase the noise reduction; however, the performance of the single channel ANC system decreases with frequency and deteriorates when there are many noise sources present simultaneously as in the traffic noise scenario. Experiments were conducted in a laboratory environment for one noise source and three noise sources, and the results are consistent with the simulations.