Cameron, R, Sankaran, S & Scales, J 2015, 'Mixed Methods Use in Project Management Research', Project Management Journal, vol. 46, no. 2, pp. 90-104.
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Mixed methods research is increasingly being used in business and management disciplines, in spite of positivist traditions. The aim of the study is twofold: (1) to examine the types of mixed methods approaches being used, and (2) to determine the quality of the reporting of mixed methods studies published in the field of project management. A retrospective content analysis of articles from three ranked project management journals was undertaken for a sample period of 2004 to 2010. Our findings suggest the field of project management is in need of capacity building in relation to the good reporting of mixed methods studies.
Cheng, J, Kim, J, Shao, J & Zhang, W 2015, 'Robust linear pose graph-based SLAM', Robotics and Autonomous Systems, vol. 72, pp. 71-82.
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Dick, B, Sankaran, S, Shaw, K, Kelly, J, Soar, J, Davies, A & Banbury, A 2015, 'Value Co-creation with Stakeholders Using Action Research as a Meta-methodology in a Funded Research Project', Project Management Journal, vol. 46, no. 2, pp. 36-46.
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A large applied research study is a challenging exercise in project management and is often unpredictable because of its complexity. In the beginning, funding bodies, ethics committees, and participating organizations expect a plan of what is intended. As the research evolves, researchers must meet the expectations of stakeholders while being responsive to the emergent reality that the research faces and partly uncovers. This article describes action research used as an umbrella process that enabled us to manage the research project. We used action research as a meta-methodology—that is, a process that can subsume multiple subprocesses and under which these contradicting demands can be satisfied. In particular, two characteristics enable action research to do this. One is its cyclic process, iteratively tracing out a rhythm of planning, acting, and observing the results. The other is the nesting of its cycles, applied at scales ranging from the overall study to the moment-by-moment facilitation. We illustrate this use of action research with examples from a long-term applied study of leadership in faith-based, not-for-profit organizations.
Fahri, J, Biesenthal, C, Pollack, J & Sankaran, S 2015, 'Understanding Megaproject Success beyond the Project Close-Out Stage', Construction Economics and Building, vol. 15, no. 3, pp. 48-58.
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Project success has always been an important topic in the project management literature. One of the main discussions is concerned with how a project’s success is evaluated and what factors lead to achieving this success. Traditionally project success has been measured at the point where the project outputs are handed over, after the close out phase. Recently, questions have been raised in the literature as to whether we should be evaluating project success beyond the close out phase, to better account for organizational and societal outcomes. However, not much has been published about how the long term impacts and outcomes are measured. This is of particular concern in megaprojects as they often attract a high level of public attention and political interest, and have both direct and indirect impacts on the community, environment, and national budgets. In this paper the authors review success factors and criteria that are applicable to projects in general and megaprojects in particular. They identify the significance of evaluating outcomes and impact and propose an ex-post project evaluation (EPPE) framework for megaprojects.
Fitch, R, Sukkarieh, S, Bergerman, M & van Henten, E 2015, '2015 IEEE RAS Summer School on Agricultural Robotics', IEEE ROBOTICS & AUTOMATION MAGAZINE, vol. 22, no. 2, pp. 96-98.
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Agricultural robotics is an area of growing interest with the potential to bring about profound economic and social benefits. Interest in this area is motivated by the need to improve the industries and processes that feed the planet. Autonomous systems are currently being developed for tasks such as pruning, thinning, harvesting, mowing, targeted spraying, nonchemical weed control, and high-resolution crop surveillance. A new cohort of people in agriculture will develop, commercialize, and operate such systems. Social events played an important part in the success of the school. On the first day, participants introduced themselves via a lightning round that consisted of a rapid sequence of single-slide, 60-s presentations. A participant poster session followed, promoting informal discussion in a semistructured environment.
Forsythe, P, Sankaran, S & Biesenthal, C 2015, 'How Far Can BIM Reduce Information Asymmetry in the Australian Construction Context?', Project Management Journal, vol. 46, no. 3, pp. 75-87.
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Building Information Modeling (BIM) systems are increasingly used in construction projects. Theoretically, these systems provide greater transparency and access to construction project information and, in doing so, should reduce the information asymmetry that commonly arises in construction contracting relationships. This typically occurs when suppliers of products and services opportunistically take advantage of the client due to the imbalance in information. The article therefore explores whether or not the high level of information content offered by BIM and the potential for sharing that information among contracting parties means that the information asymmetry can be alleviated using BIM. In order to investigate this, evidence was collected through three purposively sampled case studies of large principal organizations undertaking projects in Australia—each representing a different type of customer in the supply chain on construction projects. Our findings suggest a gap between the theoretical potential and practical application of BIM to reduce information asymmetry. The study found that, although BIM has the capability to reduce information asymmetry, it has not reached a mature enough stage in the Australian construction industry to clearly confirm that it actually reduces the problem. There is even a degree of evidence that, under certain circumstances, a reverse asymmetry may exist in which a client has the technical knowledge to more successfully analyze the BIM model (relative to the organizations they contract with) and then use the resulting information to their own opportunistic advantage.
Jacobs, DA & Waldron, KJ 2015, 'Modeling Inelastic Collisions With the Hunt–Crossley Model Using the Energetic Coefficient of Restitution', Journal of Computational and Nonlinear Dynamics, vol. 10, no. 2.
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Modeling collision and contact accurately is essential to simulating many multibody systems. The three parameter Hunt–Crossley model is a continuous collision model for representing the contact dynamics of viscoelastic systems. By augmenting Hertz's elastic theory with a nonlinear damper, Hunt and Crossley captured part of the viscoelastic and velocity dependent behavior found in many systems. In the Hunt–Crossley model, the power parameter and the elastic coefficient can be related to the physical properties through Hertz's elastic theory but the damping coefficient cannot. Generally, the damping coefficient is related to an empirical measurement, the coefficient of restitution. Over the past few decades, several authors have posed relationships between the coefficient of restitution and the damping constant but key challenges remain. In the first portion of the paper, we derive an approximate expression for Stronge's (energetic) coefficient of restitution that has better accuracy for high velocities and low coefficient of restitution values than the published solutions based on Taylor series approximations. We present one method for selecting the model parameters from five empirical measurements using a genetic optimization routine. In the second portion of the paper, we investigate the application of the Hunt–Crossley model to an inhomogeneous system of a rubber covered aluminum sphere on a plate. Although this system does not fit the inclusion criteria for the Hunt–Crossley, it is representative of many systems of interest where authors have chosen the Hunt–Crossley model to represent the contact dynamics. The results show that a fitted model well predicts collision behavior at low values of the coefficient of restitution.
Kassir, A, Fitch, R & Sukkarieh, S 2015, 'Communication-aware information gathering with dynamic information flow', INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH, vol. 34, no. 2, pp. 173-200.
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© The Author(s) 2014. We are interested in the problem of how to improve estimation in multi-robot information gathering systems by actively controlling the rate of communication between robots. Communication is essential in such systems for decentralized data fusion and decision-making, but wireless networks impose capacity constraints that are frequently overlooked. In order to make efficient use of available capacity, it is necessary to consider a fundamental trade-off between communication cost, computation cost and information value. We introduce a new problem, dynamic information flow, that formalizes this trade-off in terms of decentralized constrained optimization. We propose algorithms that dynamically adjust the data rate of each communication link to maximize an information gain metric subject to constraints on communication and computation resources. The metric is balanced against the communication resources required to transmit data and the computation cost of processing sensor data to form observations. The optimization process selectively routes raw sensor data or processed observation data to zero, one or many robots. Our algorithms therefore allow large systems with many different types of sensors and computational resources to maximize information gain performance while satisfying realistic communication constraints. We also present experimental results with multiple ground robots and multiple sensor types that demonstrate the benefit of dynamic information flow in comparison to simpler bandwidth-limiting methods.
Li, Q-S, Xiong, R, Huang, S & Huang, Y-M 2015, 'Building a dense surface map incrementally from semi-dense point cloud and RGBimages', Frontiers of Information Technology & Electronic Engineering, vol. 16, no. 7, pp. 594-606.
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© 2015, Journal of Zhejiang University Science Editorial Office and Springer-Verlag Berlin Heidelberg. Building and using maps is a fundamental issue for bionic robots in field applications. A dense surface map, which offers rich visual and geometric information, is an ideal representation of the environment for indoor/outdoor localization, navigation, and recognition tasks of these robots. Since most bionic robots can use only small light-weight laser scanners and cameras to acquire semi-dense point cloud and RGB images, we propose a method to generate a consistent and dense surface map from this kind of semi-dense point cloud and RGB images. The method contains two main steps: (1) generate a dense surface for every single scan of point cloud and its corresponding image(s) and (2) incrementally fuse the dense surface of a new scan into the whole map. In step (1) edge-aware resampling is realized by segmenting the scan of a point cloud in advance and resampling each sub-cloud separately. Noise within the scan is reduced and a dense surface is generated. In step (2) the average surface is estimated probabilistically and the non-coincidence of different scans is eliminated. Experiments demonstrate that our method works well in both indoor and outdoor semi-structured environments where there are regularly shaped objects.
Liu, H, Hou, X, Kim, J & Zhong, Y 2015, 'Decoupled Robust Velocity Control for Uncertain Quadrotors', Asian Journal of Control, vol. 17, no. 1, pp. 225-233.
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AbstractIn this paper, a decoupled robust velocity control method is investigated for a quadrotor. Although the quadrotor dynamics involves inter‐axis coupling and nonlinearity, the quadrotor system is divided into four single‐input single‐output (SISO) subsystems. For each subsystem, a linear time‐invariant robust controller is proposed, which uses its own states and consists of a nominal controller and a robust compensator. The nominal controller is designed by the proportional‐integral‐derivative (PID) control method to achieve the desired tracking for the nominal system. A robust compensator is added to restrain the influence of the parametric uncertainties, nonlinear dynamics, coupling, and external disturbances. The tracking error of each subsystem is proven to converge into an a priori set in the neighborhood of the origin in a finite time. Experimental results on the quadrotor demonstrate the effectiveness of the proposed control method.
Martín, F, Miró, JV & Moreno, L 2015, 'RGB-D DE-based Scan Matching: Exploiting Colour Properties in Registration', Journal of Intelligent & Robotic Systems, vol. 80, no. 1, pp. 71-85.
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© 2014, Springer Science+Business Media Dordrecht. Colour plays a fundamental role in the perception process of humans. In robotics, the exploitation of this type of information has become increasingly important in many different tasks. The development of new sensors has made it possible to obtain colour information together with depth information about the environment. We have recently developed a scan matching algorithm based on evolutionary concepts (Differential Evolution). The main objective of this work is to include colour properties in the registration process, studying how colour can be used to improve the scan matching process. In particular, we have designed a filter to extract the most significant points of a RGB-D scan based on the Delta E divergence between neighbours. In addition, colour properties have also been included in the fitness function of the scan matching method. Our approach has been tested in a real environment and the most significant conclusion is the improvement of the algorithm performance when measuring the valley of convergence.
Peters, G & Paul, G 2015, 'Maintaining an old icon with a new technology', Journal of Protective Coatings and Linings, vol. 32, no. 8, pp. 22-31.
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The latest technological advancements are being used in maintaining the Sydney Harbor bridge. The latest planned maintenance involving abrasive blast-cleaning of the old paint back to bare metal has provided the opportunity for robotic technology to be used to assist maintenance workers engaged in restoration work on the bridge. Rosie and Sandy are two autonomous robots that have been performing some of the more repetitive and straining blast work on the southern side approach spans under the road deck of the bridge.
Piyathilaka, L & Kodagoda, S 2015, 'Learning Hidden Human Context in 3D Office Scenes by Mapping Affordances Through Virtual Humans.', Unmanned Syst., vol. 3, no. 04, pp. 299-310.
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Ability to learn human context in an environment could be one of the most desired fundamental abilities that a robot should have when sharing a workspace with human co-workers. Arguably, a robot with appropriate human context awareness could lead to a better human–robot interaction. In this paper, we address the problem of learning human context in an office environment by only using 3D point cloud data. Our approach is based on the concept of affordance-map, which involves mapping latent human actions in a given environment by looking at geometric features of the environment. This enables us to learn the human context in the environment without observing real human behaviors which themselves are a nontrivial task to detect. Once learned, affordance-map allows us to assign an affordance cost value for each grid location of the map. These cost maps are later used to develop an active object search strategy and to develop a context-aware global path planning strategy.
Sankaran, S, Abeysuriya, K, Gray, J & Kachenko, A 2015, 'Mellow Yellow: Taking a Systems Thinking Approach to Designing Research on Transitioning to More Sustainable Sewage Management', Systems Research and Behavioral Science, vol. 32, no. 3, pp. 330-343.
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This paper will explain how a framework derived from systems thinking, including soft systems methodology and the use of action research as a methodology, shaped a research project addressing an area of application (sustainable sanitation). The research used F (intellectual framework) M (methodology for using F) to address A (area of application) for understanding rational intervention in human affairs proposed by Peter Checkland in the 1980s. This Australia‐first research project was conducted by a multidisciplinary team of collaborators from academia, industry and government that included researchers, practitioners and students. It explored the use of innovative urine‐diverting toilets in an institutional setting. The paper is focussed on the initial stages of the project—the project design and early investigative phase, and demonstrates how systems thinking and a transdisciplinary research approach were used to structure a complex problem related to sustainability, a problem that infringed on social and cultural issues. Copyright © 2013 John Wiley & Sons, Ltd.
Sun, Y, Zhao, L, Huang, S, Yan, L & Dissanayake, G 2015, 'Line matching based on planar homography for stereo aerial images', ISPRS Journal of Photogrammetry and Remote Sensing, vol. 104, pp. 1-17.
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© 2015 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). We propose an efficient line matching algorithm for a pair of calibrated aerial photogrammetric images, which makes use of sparse 3D points triangulated from 2D point feature correspondences to guide line matching based on planar homography. Two different strategies are applied in the proposed line matching algorithm for two different cases. When three or more points can be found coplanar with the line segment to be matched, the points are used to fit a plane and obtain an accurate planar homography. When one or two points can be found, the approximate terrain plane parallel to the line segment is utilized to compute an approximate planar homography. Six pairs of rural or urban aerial images are used to demonstrate the efficiency and validity of the proposed algorithm. Compared with line matching based on 2D point feature correspondences, the proposed method can increase the number of correctly matched line segments. In addition, compared with most line matching methods that do not use 2D point feature correspondences, the proposed method has better efficiency, although it obtains fewer matches. The C/C++ source code for the proposed algorithm is available at http://services.eng.uts.edu.au/~sdhuang/research.htm.
Valiente, D, Ghaffari Jadidi, M, Valls Miró, J, Gil, A & Reinoso, O 2015, 'Information-based view initialization in visual SLAM with a single omnidirectional camera', Robotics and Autonomous Systems, vol. 72, pp. 93-104.
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© 2015 Elsevier B.V. All rights reserved. This paper presents a novel mechanism to initiate new views within the map building process for an EKF-based visual SLAM (Simultaneous Localization and Mapping) approach using omnidirectional images. In presence of non-linearities, the EKF is very likely to compromise the final estimation. Particularly, the omnidirectional observation model induces non-linear errors, thus it becomes a potential source of uncertainty. To deal with this issue we propose a novel mechanism for view initialization which accounts for information gain and losses more efficiently. The main outcome of this contribution is the reduction of the map uncertainty and thus the higher consistency of the final estimation. Its basis relies on a Gaussian Process to infer an information distribution model from sensor data. This model represents feature points existence probabilities and their information content analysis leads to the proposed view initialization scheme. To demonstrate the suitability and effectiveness of the approach we present a series of real data experiments conducted with a robot equipped with a camera sensor and map model solely based on omnidirectional views. The results reveal a beneficial reduction on the uncertainty but also on the error in the pose and the map estimate.
Wang, H, Huang, S, Khosoussi, K, Frese, U, Dissanayake, G & Liu, B 2015, 'Dimensionality reduction for point feature SLAM problems with spherical covariance matrices', Automatica, vol. 51, pp. 149-157.
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© 2014 Elsevier Ltd. All rights reserved. The main contribution of this paper is the dimensionality reduction for multiple-step 2D point feature based Simultaneous Localization and Mapping (SLAM), which is an extension of our previous work on one-step SLAM (Wang et al.; 2013). It has been proved that SLAM with multiple robot poses and a number of point feature positions as variables is equivalent to an optimization problem with only the robot orientations as variables, when the associated uncertainties can be described using spherical covariance matrices. This reduces the dimension of original problem from 3m+2n to m only (where m is the number of poses and n is the number of features). The optimization problem after dimensionality reduction can be solved numerically using the unconstrained optimization algorithms. While dimensionality reduction may not provide computational saving for all nonlinear optimization problems, for some SLAM problems we can achieve benefits such as improvement on time consumption and convergence. For the special case of two-step SLAM when the orientation information from odometry is not incorporated, an algorithm that can guarantee to obtain the globally optimal solution (in the maximum likelihood sense) is derived. Simulation and experimental datasets are used to verify the equivalence between the reduced nonlinear optimization problem and the original full optimization problem, as well as the proposed new algorithm for obtaining the globally optimal solution for two-step SLAM.
Wang, Y, Xiong, R & Huang, S 2015, 'A pose pruning driven solution to pose feature GraphSLAM', Advanced Robotics, vol. 29, no. 10, pp. 683-698.
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© 2015 Taylor & Francis and The Robotics Society of Japan. To build consistent feature-based map for the environment, GraphSLAM forms the graph using the collected information, with poses of robot and features being nodes while the odometry and observations being binary edges (edge links to two nodes). As the number of kept nodes grows unboundedly while robot moves, this method will become intractable for long-duration operation. In this paper, we propose a pose pruning-driven solution for pose feature Simultaneous localization and mapping by relating the size of graph to the size of map instead of the length of trajectory. It consists of two steps: (1) An online pose pruning algorithm that can select a pose to be pruned based on the contribution of the pose. Different from conventional methods considering the spatial distance between poses, the contribution is based on the feature observations of poses, taking mapping into consideration. (2) An edge generation algorithm that can build new consistent binary edges from -nary edge (edge links to nodes) induced by marginalizing the pruned pose. The type of new edges remains invariant (i.e. they are either odometry or pose to feature observations), so no extra change is required to be made on the GraphSLAM optimizer, making the proposed solution modular. In the experiment, we first employ this system on simulation data-sets to show how it works. Then the large-scale data-sets: DLR, Victoria Park, and CityTrees10000 are used to evaluate its performance.
Wankhade, P & Sankaran, S 2015, 'Guest editorial', International Journal of Emergency Services, vol. 4, no. 1.
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Zhao, L, Huang, S, Sun, Y, Yan, L & Dissanayake, G 2015, 'ParallaxBA: bundle adjustment using parallax angle feature parametrization', The International Journal of Robotics Research, vol. 34, no. 4-5, pp. 493-516.
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The main contribution of this paper is a novel feature parametrization based on parallax angles for bundle adjustment (BA) in structure and motion estimation from monocular images. It is demonstrated that under certain conditions, describing feature locations using their Euclidean XYZ coordinates or using inverse depth in BA leads to ill-conditioned normal equations as well as objective functions that have very small gradients with respect to some of the parameters describing feature locations. The proposed parallax angle feature parametrization in BA (ParallaxBA) avoids both of the above problems leading to better convergence properties and more accurate motion and structure estimates. Simulation and experimental datasets are used to demonstrate the impact of different feature parametrizations on BA, and the improved convergence, efficiency and accuracy of the proposed ParallaxBA algorithm when compared with some existing BA packages such as SBA, sSBA and g2o. The C/C++ source code of ParallaxBA is available on OpenSLAM ( https://openslam.org/ ).
Zhao, L, Huang, S, Yan, L & Dissanayake, G 2015, 'A new feature parametrization for monocular SLAM using line features', Robotica, vol. 33, no. 3, pp. 513-536.
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SUMMARYThis paper presents a new monocular SLAM algorithm that uses straight lines extracted from images to represent the environment. A line is parametrized by two pairs of azimuth and elevation angles together with the two corresponding camera centres as anchors making the feature initialization relatively straightforward. There is no redundancy in the state vector as this is a minimal representation. A bundle adjustment (BA) algorithm that minimizes the reprojection error of the line features is developed for solving the monocular SLAM problem with only line features. A new map joining algorithm which can automatically optimize the relative scales of the local maps is used to combine the local maps generated using BA. Results from both simulations and experimental datasets are used to demonstrate the accuracy and consistency of the proposed BA and map joining algorithms.
Abeywardena, D & Dissanayake, G 1970, 'Tightly-Coupled Model Aided Visual-Inertial Fusion for Quadrotor Micro Air Vehicles', Results of the 9th International Conference, International Conference on Field and Service Robotics, Springer International Publishing, Toronto, Canada, pp. 153-166.
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The main contribution of this paper is a tightly-coupled visual-inertial fusion algorithm for simultaneous localisation and mapping (SLAM) for a quadrotor micro aerial vehicle (MAV). Proposed algorithm is based on an extended Kalman filter that uses a platform specific dynamic model to integrate information from an inertial measurement unit (IMU) and a monocular camera on board the MAV. MAV dynamic model exploits the unique characteristics of the quadrotor, making it possible to generate relatively accurate motion predictions. This, together with an undelayed feature initialisation strategy based on inverse depth parametrisation enables more effective feature tracking and reliable visual SLAM with a small number of features even during rapid manoeuvres. Experimental results are presented to demonstrate the effectiveness of the proposed algorithm.
Abeywardena, D, Pounds, P, Hunt, D & Dissanayake, G 1970, 'Design and development of ReCOPTER: An open source ros-based multi-rotor platform for research', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Canberra, Australia, pp. 1-10.
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Selection of multi-rotor aircraft systems for robotics research is a trade-off between competing objectives. While Commercial Off The Shelf systems are fast to set up and provide a ready-made platform, they often lack complete documentation and have limited extensibility for allowing researchers to modify them for scientific work. Conversely, developing an aircraft from the ground up is labour intensive and time consuming, and requires substantial experience to ensure a satisfactory result. This paper ranks common robotic multi-rotor air- craft used in research against several criteria for openness, extensibility and performance. We propose a standard platform using open components and an open-source design, specifically geared to the needs of the research community.
Ang, KC, Killen, CP & Sankaran, S 1970, 'Value constructs in multi-stakeholder environments that influence project portfolio decision making', Euram'15 Uncertainty is a great opportunity - Programme Book and E-proceedings, Annual Conference of the European Academy of Management, European Academy of Management, Warsaw, Poland.
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Abstract: A key goal for project portfolio management (PPM) is to maximize strategic value across the portfolio. In certain industries, particularly in the context of non-commercial sectors, the ‘value’ generated by the portfolio may not always fit with typical PPM frameworks that emphasize financial value. Furthermore project and portfolio ‘value’ are complex phenomena due to the multiple and sometimes contradicting expectations demanded by multiple stakeholders that participate in and influence the ways that PPM decisions incorporate value. This paper draws on organization, business, stakeholder and project management literature to consider different perspectives of value, and integrates stakeholder theory and sensemaking in its investigation of value in multi-stakeholder portfolioenvironments. It highlights the key question ‘Value for whom, value by whom’ and proposes that multiple case-studies of a diverse sample of project-based organizations would be useful to address this question. A Hybrid Delphi study using expert panels is also proposed to triangulate the findings.Keywords: project portfolio management, value, stakeholders, sensemaking, decision making
Ang, KCS, Killen, CP & Sankaran, S 1970, 'Unanticipated value creation: Sensemaking and the value spectrum in partnership projects', Proceedings of IRNOP 2015, International Research Network on Organising by Projects, IRNOP 2015, International Research Network on Organising by Projects, International Research Network on Organizing by Projects (IRNOP), London, UK.
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This paper explores the dimensions of value across a partnership project (that requires collaboration from two or more organisations), and highlights how unanticipated values from a project can add value to the overall portfolio. Insights into the complexities of defining and managing value derive from a study investigating managerial decisions to persist with a partnership project despite indications of possible failure, and how value was ultimately created. The study highlights a variety of valuable outcomes from project and portfolio activities. Sensemaking processes are illustrated and a value spectrum model is presented to provide guidance for portfolio decision makers involved in partnership projects.
Best, G, Fitch, R & IEEE 1970, 'Bayesian Intention Inference for Trajectory Prediction with an Unknown Goal Destination', 2015 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS), IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Hamburg, Germany, pp. 5817-5823.
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© 2015 IEEE. Contextual cues can provide a rich source of information for robots that operate in the presence of other agents such as people, animals, vehicles and fellow robots. We are interested in context, in the form of the behavioural intent of an agent, for enhanced trajectory prediction. We present a Bayesian framework that estimates both the intended goal destination and future trajectory of a mobile agent moving among multiple static obstacles. Our method is based on multi-modal hypotheses of the intended goal, and is focused primarily on the long-term trajectory of the agent. We propose a computationally efficient solution and demonstrate its behaviour in a pedestrian scenario with a real-world data set. Results show the benefits of our method in comparison to traditional trajectory prediction methods and illustrate the feasibility of integration with higher-level planning algorithms.
Best, G, Martens, W & Fitch, R 1970, 'A Spatiotemporal Optimal Stopping Problem for Mission Monitoring with Stationary Viewpoints', Robotics: Science and Systems XI, Robotics: Science and Systems 2015, Robotics: Science and Systems Foundation, Rome, Italy, pp. 1-10.
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© 2015, MIT Press Journals. All rights reserved. We consider an optimal stopping formulation of the mission monitoring problem, where a monitor vehicle must remain in close proximity to an autonomous robot that stochastically follows a pre-planned trajectory. This problem arises when autonomous underwater vehicles are monitored by surface vessels, and in a diverse range of other scenarios. The key problem characteristics we consider are that the monitor must remain stationary while observing the robot, and that the robot motion is modelled in general as a stochastic process. We propose a resolution-complete algorithm for this problem that runs in polynomial time. The algorithm is based on a sweep-plane approach and generates a motion plan that maximises the expected observation time. A variety of stochastic models may be used to represent the expected robot trajectory. We present results drawn from real AUV trajectories and Monte Carlo simulations that validate the correctness of our algorithm and its feasibility in practice.
Carmichael, MG & Dikai Liu 1970, 'Upper limb strength estimation of physically impaired persons using a musculoskeletal model: A sensitivity analysis', 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Milan, Italy, pp. 2438-2441.
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© 2015 IEEE. Sensitivity of upper limb strength calculated from a musculoskeletal model was analyzed, with focus on how the sensitivity is affected when the model is adapted to represent a person with physical impairment. Sensitivity was calculated with respect to four muscle-tendon parameters: muscle peak isometric force, muscle optimal length, muscle pennation, and tendon slack length. Results obtained from a musculoskeletal model of average strength showed highest sensitivity to tendon slack length, followed by muscle optimal length and peak isometric force, which is consistent with existing studies. Muscle pennation angle was relatively insensitive. The analysis was repeated after adapting the musculoskeletal model to represent persons with varying severities of physical impairment. Results showed that utilizing the weakened model significantly increased the sensitivity of the calculated strength at the hand, with parameters previously insensitive becoming highly sensitive. This increased sensitivity presents a significant challenge in applications utilizing musculoskeletal models to represent impaired individuals.
Carmichael, MG & Liu, DK 1970, 'Human Biomechanical Model Based Optimal Design of Assistive Shoulder Exoskeleton', Springer Tracts in Advanced Robotics, International Conference on Field and Service Robotics, Springer International Publishing, Brisbane, QLD, Australia, pp. 245-258.
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© Springer International Publishing Switzerland 2015. Robotic exoskeletons are being developed to assist humans in tasks such as robotic rehabilitation, assistive living, industrial and other service applications. Exoskeletons for the upper limb are required to encompass the shoulder whilst achieving a range of motion so as to not impede the wearer, avoid collisions with the wearer, and avoid kinematic singularities during operation. However this is particularly challenging due to the large range of motion of the human shoulder. In this paper a biomechanical model based optimisation is applied to the design of a shoulder exoskeleton with the objective of maximising shoulder range of motion. A biomechanical model defines the healthy range of motion of the human shoulder. A genetic algorithm maximises the range of motion of the exoskeleton towards that of the human, whilst taking into account collisions and kinematic singularities. It is shown how the optimisation can increase the exoskeleton range of motion towards that equivalent of the human, or towards a subset of human range of motion relevant to specific applications.
Carmichael, MG, Khonasty, R & Liu, D 1970, 'A multi-stage design framework for the development of task-specific robotic exoskeletons', 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Milan, Italy, pp. 1176-1180.
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© 2015 IEEE. This work presents a multi-stage design framework for developing robotic exoskeletons suited for specific tasks, such as individualized exercises that meet the needs of patients undergoing physical therapy. The framework systematically develops the exoskeleton based on the required task space, represented by a set of limb poses which may be defined directly, or indirectly using means such as motion capture. The design process seeks to maximize the poses inside and surrounding the defined task space whilst ensuring additional criteria required to perform the task are satisfied. A case study demonstrates the framework applied to develop two variations of shoulder exoskeleton suited for two specific upper limb activities. Prototype exoskeletons based on the framework's outcomes were constructed, and their suitability for use in their intended tasks were evaluated.
Cliff, O, Fitch, R, Sukkarieh, S, Saunders, D & Heinsohn, R 1970, 'Online Localization of Radio-Tagged Wildlife with an Autonomous Aerial Robot System', Robotics: Science and Systems XI, Robotics: Science and Systems 2015, Robotics: Science and Systems Foundation, Rome, Italy, pp. 1-9.
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© 2015, MIT Press Journals. All rights reserved. The application of autonomous robots to efficiently locate small wildlife species has the potential to provide significant ecological insights not previously possible using traditional land-based survey techniques, and a basis for improved conservation policy and management. We present an approach for autonomously localizing radio-tagged wildlife using a small aerial robot. We present a novel two-point phased array antenna system that yields unambiguous bearing measurements and an associated uncertainty measure. Our estimation and information-based planning algorithms incorporate this bearing uncertainty to choose observation points that improve confidence in the location estimate. These algorithms run online in real time and we report experimental results that show successful autonomous localization of stationary radio tags and live radio-tagged birds.
Colborne-Veel, P, Kirchner, N & Alempijevic, A 1970, 'Towards more train paths through early passenger intention inference', ATRF 2015 - Australasian Transport Research Forum 2015, Proceedings, Australasian Transport Research Forum, ATRF, Sydney, Australia, pp. 1-14.
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© 2015 ATRF, Commonwealth of Australia. All rights reserved. In public train stations, the designed way finding tends to induce individuals to conform to specific egress patterns. Whilst this is desirable for a number of reasons, it can cumulate into congestion at specific points in the station. Which, in turn, can increase dwell time; for example, loading and unloading time increases with concentrations of people trying to load/unload onto the same carriage. Clearly, an influencing strategy that is more responsive to the current station situation could have advantages. Our prior research studies in Perth Station demonstrated the feasibility of reliably and predictably influencing passengers egress patterns in real time during operations. This capability suggests the possibility of active counterbalancing of the egress-alternatives while maintaining way finding. However, the prerequisite for such capability is the availability of knowledge of passenger's intention at a point in their journey where viable egress-alternatives to their destination exist. This work details an approach towards an early (in the passenger journey) passenger intention inference system necessary to enable active egress-alternative influencing. Our contextually grounded approach infers intention through reasoning upon observed system and passenger cues in conjunction with a-priori knowledge of how train stations are used. The empirical validation of our intention inference system, which was conducted with data acquired during operations on a platform in Brisbane’s Central train station in Queensland, is presented and discussed. The findings are then employed to argue the feasibility of an influencing system to reduce passenger congestion and the potential service impacts.
Colborne-Veel, P, Kirchner, N & Alempijevic, A 1970, 'Towards more train paths through early passenger intention inference', ATRF 2015 - Australasian Transport Research Forum 2015, Proceedings.
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In public train stations, the designed way finding tends to induce individuals to conform to specific egress patterns. Whilst this is desirable for a number of reasons, it can cumulate into congestion at specific points in the station. Which, in turn, can increase dwell time; for example, loading and unloading time increases with concentrations of people trying to load/unload onto the same carriage. Clearly, an influencing strategy that is more responsive to the current station situation could have advantages. Our prior research studies in Perth Station demonstrated the feasibility of reliably and predictably influencing passengers egress patterns in real time during operations. This capability suggests the possibility of active counterbalancing of the egress-alternatives while maintaining way finding. However, the prerequisite for such capability is the availability of knowledge of passenger's intention at a point in their journey where viable egress-alternatives to their destination exist. This work details an approach towards an early (in the passenger journey) passenger intention inference system necessary to enable active egress-alternative influencing. Our contextually grounded approach infers intention through reasoning upon observed system and passenger cues in conjunction with a-priori knowledge of how train stations are used. The empirical validation of our intention inference system, which was conducted with data acquired during operations on a platform in Brisbane’s Central train station in Queensland, is presented and discussed. The findings are then employed to argue the feasibility of an influencing system to reduce passenger congestion and the potential service impacts.
Collart, J, Kirchner, N, Alempijevic, A & Zeibots, M 1970, 'Foundation technology for developing an autonomous Complex Dwell-time Diagnostics (CDD) Tool', ATRF 2015 - Australasian Transport Research Forum 2015, Proceedings.
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As the demand for rail services grows, intense pressure is placed on stations at the centre of rail networks where large crowds of rail passengers alight and board trains during peak periods. The time it takes for this to occur — the dwell-time — can become extended when high numbers of people congest and cross paths. Where a track section is operating at short headways, extended dwell-times can cause delays to scheduled services that can in turn cause a cascade of delays that eventually affect entire networks. Where networks are operating at close to their ceiling capacity, dwell-time management is essential and in most cases requires the introduction of special operating procedures. This paper details our work towards developing an autonomous Complex Dwell-time Diagnostics (CDD) Tool — a low cost technology, capable of providing information on multiple dwell events in real time. At present, rail operators are not able to access reliable and detailed enough data on train dwell operations and passenger behaviour. This is because much of the necessary data has to be collected manually. The lack of rich data means train crews and platform staff are not empowered to do all they could to potentially stabilise and reduce dwell-times. By better supporting service providers with high quality data analysis, the number of viable train paths can be increased, potentially delaying the need to invest in high cost hard infrastructures such as additional tracks. The foundation technology needed to create CDD discussed in this paper comprises a 3D image data based autonomous system capable of detecting dwell events during operations and then create business information that can be accessed by service providers in real time during rail operations. Initial tests of the technology have been carried out at Brisbane Central rail station. A discussion of the results to date is provided and their implications for next steps.
Collart, J, Kirchner, N, Alempijevic, A & Zeibots, M 1970, 'Foundation technology for developing an autonomous Complex Dwell-time Diagnostics (CDD) Tool', ATRF 2015 - Australasian Transport Research Forum 2015, Proceedings, Australasian Transport Research Forum, ATRF, Sydney, Australia, pp. 1-13.
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© 2015 ATRF, Commonwealth of Australia. All rights reserved. As the demand for rail services grows, intense pressure is placed on stations at the centre of rail networks where large crowds of rail passengers alight and board trains during peak periods. The time it takes for this to occur — the dwell-time — can become extended when high numbers of people congest and cross paths. Where a track section is operating at short headways, extended dwell-times can cause delays to scheduled services that can in turn cause a cascade of delays that eventually affect entire networks. Where networks are operating at close to their ceiling capacity, dwell-time management is essential and in most cases requires the introduction of special operating procedures. This paper details our work towards developing an autonomous Complex Dwell-time Diagnostics (CDD) Tool — a low cost technology, capable of providing information on multiple dwell events in real time. At present, rail operators are not able to access reliable and detailed enough data on train dwell operations and passenger behaviour. This is because much of the necessary data has to be collected manually. The lack of rich data means train crews and platform staff are not empowered to do all they could to potentially stabilise and reduce dwell-times. By better supporting service providers with high quality data analysis, the number of viable train paths can be increased, potentially delaying the need to invest in high cost hard infrastructures such as additional tracks. The foundation technology needed to create CDD discussed in this paper comprises a 3D image data based autonomous system capable of detecting dwell events during operations and then create business information that can be accessed by service providers in real time during rail operations. Initial tests of the technology have been carried out at Brisbane Central rail station. A discussion of the results to date is provided and their implications for next steps.
Falque, R, Vidal-Calleja, T, Miro, JV & IEEE 1970, 'Kidnapped Laser-Scanner for Evaluation of RFEC Tool', 2015 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS), IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Hamburg, Germany, pp. 313-318.
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© 2015 IEEE. An algorithm is proposed for matching data from different sensing modalities. The problem is formalised as a kidnapped robot problem, where Bayesian fusion is used to find the most likely location where both modalities agree. The key idea of our algorithm is to model the correlation between the two modalities as a likelihood used to update a location prior. Data, in this case, is represented as 2.5D thickness maps from a laser scanner and a Remote Field Eddy Current (RFEC) tool, used in non-destructive testing to assess the condition of infrastructures. The laser data is limited, while RFEC data is continuous. Given some prior in location, the aim is to find the 2.5D thickness map from the laser that corresponds to the RFEC data, which should be noted is highly noisy. Real data from CCTV inspections of water pipes are used to validate the proposed approach.
Forsythe, P, Sankaran, S, Subramanyan, H & Biesenthal, C 1970, 'The role of BIM in reducing information asymmetry in construction projects', Project Management Excellence: Education, Research and Practice, PMI India Project Management Research & Academic Conference, PMI Organization Centre, Mumbai, India, pp. 115-125.
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The purpose of this paper is to determine the impact of Building Information Modelling (BIM) on Information Asymmetry (IA) in construction projects. Further, the focus is also on a comparative analysis of the extent to which firms in Australia and India are looking at BIM as a solution to IA in construction projects. IA is a common concern in contracting relationships during the procurement of construction projects. While the agent (contractor) opportunistically takes advantage of the Principal (Client), the Principal is continually exploring the best means of managing information on projects. The question that needs to be answered is: To what extent in real-time scenarios, can BIM help reduce the imbalance in information between the two contracting parties? Principal agency theory proposes three issues due to IA including: Adverse Selection, Moral Hazard and Hold Up which are all typical ways in which an information imbalance can be used opportunistically to exploit the Principal. This paper discusses the manifestation of IA in construction procurement and project delivery, the impact of contractual controls commonly used to manage IA, and the potential of BIM to control IA. Contractor, Developer and consultants in India and Australia were interviewed and their responses are presented in the paper. Among the three areas of IA, respondents were of the opinion that BIM can help to a greater extent in overcoming Hold Up and Moral Hazards. While clients in the Australian context are keener and oriented towards BIM implementation, clients in India do not insist on BIM except where large developers are involved. In other words, the level of penetration of BIM in the Indian context is comparatively low. Surprisingly, while the contractors in Australia do not see significant benefits from adopting BIM, many contracting firms in India have gone ahead with BIM as they consider that it can provide a better protection under material variation. While developing hig...
Furukawa, T, Dantanarayana, L, Ziglar, J, Ranasinghe, R & Dissanayake, G 1970, 'Fast global scan matching for high-speed vehicle navigation.', MFI, IEEE International conference on Multisensor Fusion and Integration for Intelligent Systems, IEEE, San Diego, CA, USA, pp. 37-42.
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Furukawa, T, Takami, K, Tong, X, Watman, D, Hamed, A, Ranasinghe, R & Dissanayake, G 1970, 'Map-Based Navigation of an Autonomous Car Using Grid-Based Scan-to-Map Matching', Volume 3: 17th International Conference on Advanced Vehicle Technologies; 12th International Conference on Design Education; 8th Frontiers in Biomedical Devices, ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, American Society of Mechanical Engineers, Boston, Massachusetts, USA, pp. 1-10.
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This paper presents the map-based navigation of a car with autonomous capabilities using grid-based scan-to-map matching. The autonomous car used for demonstration is built based on Toyota Prius and can control the throttle, the brake and the steering by a computer. The proposed grid-based scan-to-map matching method represents a map with a finite number of grid cells, represents a scan and the map with scan points at each grid as normal distributions (NDs) and constructs a map by matching the scan NDs to the map NDs. The proposed method enables scan-based mapping at high speed while maintaining high accuracy. The representation of a grid cell of a map in terms of multiple NDs further enhances speed and accuracy. The accuracy analysis of the proposed method shows that a small robot with a wheel diameter of 8cm had yielded no loop closure error after the travel of 186m while the terminal position error by the GMapping was approximately 1m with the error growth of 1%. The application of the proposed method with the autonomous car has then demonstrated the ability of the proposed method for autonomous driving with varying and high speed and has also quantified the significance of speed for successful mapping in autonomous driving.
Gerardo-Castro, MP, Peynot, T, Ramos, F, Fitch, R & IEEE 1970, 'Non-Parametric Consistency Test for Multiple-Sensing-Modality Data Fusion', 2015 18TH INTERNATIONAL CONFERENCE ON INFORMATION FUSION (FUSION), International Conference on Information Fusion, IEEE, Washington, DC, USA, pp. 443-451.
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© 2015 IEEE. Fusing data from multiple sensing modalities, e.g. laser and radar, is a promising approach to achieve resilient perception in challenging environmental conditions. However, this may lead to catastrophic fusion in the presence of inconsistent data, i.e. when the sensors do not detect the same target due to distinct attenuation properties. It is often difficult to discriminate consistent from inconsistent data across sensing modalities using local spatial information alone. In this paper we present a novel consistency test based on the log marginal likelihood of a Gaussian process model that evaluates data from range sensors in a relative manner. A new data point is deemed to be consistent if the model statistically improves as a result of its fusion. This approach avoids the need for absolute spatial distance threshold parameters as required by previous work. We report results from object reconstruction with both synthetic and experimental data that demonstrate an improvement in reconstruction quality, particularly in cases where data points are inconsistent yet spatially proximal.
Hassan, M, Liu, D, Paul, G & Huang, S 1970, 'An approach to base placement for effective collaboration of multiple autonomous industrial robots', 2015 IEEE International Conference on Robotics and Automation (ICRA), 2015 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Washington State Convention Center in Seattle, Washington, USA, pp. 3286-3291.
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There are many benefits for the deployment of multiple autonomous industrial robots to carry out a task, particularly if the robots act in a highly collaborative manner. Collaboration can be possible when each robot is able to autonomously explore the environment, localize itself, create a map of the environment and communicate with other robots. This paper presents an approach to the modeling of the collaboration problem of multiple robots determining optimal base positions and orientations in an environment by considering the team objectives and the information shared amongst the robots. It is assumed that the robots can communicate so as to share information on the environment, their operation status and their capabilities. The approach has been applied to a team of robots that are required to perform complete surface coverage tasks such as grit-blasting and spray painting in unstructured environments. Case studies of such applications are presented to demonstrate the effectiveness of the approach.
Jadidi, MG, Miro, JV & Dissanayake, G 1970, 'Mutual information-based exploration on continuous occupancy maps', 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, Hamburg Germany, pp. 6086-6092.
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© 2015 IEEE. The problem of active perception with an autonomous robot is studied in this paper. It is proposed that the exploratory behavior of the robot be controlled using mutual information (MI) surfaces between the current map and a one-step look ahead measurements. MI surfaces highlight informative areas for exploration. A novel method for computing these surfaces is described. An approach that exploits structural dependencies of the environment and handles sparse sensor measurements to build a continuous model of the environment, that can then be used to generate MI surfaces is also proposed. A gradient field of occupancy probability distribution is regressed from sensor data as a Gaussian Process and provide frontier boundaries for further exploration. The continuous global frontier surface completely describes unexplored regions and, inherently, provides an automatic termination criterion for a desired sensitivity. The results from publicly available datasets confirm an average improvement of the proposed methodology over comparable standard and state-of-the-art exploratory methods available in the literature by more than 20% and 13% in travel distance and map entropy reduction rate, respectively.
Khosoussi, K, Huang, S & Dissanayake, G 1970, 'Exploiting the Separable Structure of SLAM', Robotics: Science and Systems XI, Robotics: Science and Systems 2015, Robotics: Science and Systems Foundation, Rome, Italy, pp. 1-10.
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© 2015, MIT Press Journals. All rights reserved. In this paper we point out an overlooked structure of SLAM that distinguishes it from a generic nonlinear least squares problem. The measurement function in most common forms of SLAM is linear with respect to robot and features' positions. Therefore, given an estimate for robot orientation, the conditionally optimal estimate for the rest of state variables can be easily obtained by solving a sparse linear-Gaussian estimation problem. We propose an algorithm to exploit this intrinsic property of SLAM by stripping the problem down to its nonlinear core, while maintaining its natural sparsity. Our algorithm can be used together with any Newton-based iterative solver and is applicable to 2D/3D pose-graph and feature-based problems. Our results suggest that iteratively solving the nonlinear core of SLAM leads to a fast and reliable convergence as compared to the state-of-the-art back-ends.
Khushaba, RN, Al-Timemy, A, Kodagoda, S & IEEE 1970, 'Influence of Multiple Dynamic Factors on the Performance of Myoelectric Pattern Recognition', 2015 37TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, Milan, pp. 1679-1682.
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© 2015 IEEE. Hand motion classification using surface Electromyogram (EMG) signals has been widely studied for the control of powered prosthetics in laboratory conditions. However, clinical applicability has been limited, as imposed by factors like electrodes shift, variations in the contraction force levels, forearm rotation angles, change of limb position and many other factors that all affect the EMG pattern recognition performance. While the impact of several of these factors on EMG parameter estimation and pattern recognition has been considered individually in previous studies, a minimum number of experiments were reported to study the influence of multiple dynamic factors. In this paper, we investigate the combined effect of varying forearm rotation angles and contraction force levels on the robustness of EMG pattern recognition, while utilizing different time-and-frequency based feature extraction methods. The EMG pattern recognition system has been validated on a set of 11 subjects (ten intact-limbed and one bilateral transradial amputee) performing six classes of hand motions, each with three different force levels, each at three different forearm rotation angles, with six EMG electrodes plus an accelerometer on the subjects' forearm. Our results suggest that the performance of the learning algorithms can be improved with the Time-Dependent Power Spectrum Descriptors (TD-PSD) utilized in our experiments, with average classification accuracies of up to 90% across all subjects, force levels, and forearm rotation angles.
Killen, CP, Clegg, S, Biesenthal, C & Sankaran, S 1970, 'Time to make space for practice-based research in project portfolio management', Asia Pacific Researchers in Organisational Studies (APROS) / European Group for Organization Studies (EGOS), Asia Pacific Researchers in Organisational Studies (APROS) / European Group for Organization Studies (EGOS), Sydney, Australia.
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Practice-based research is extending understanding in the disciplines of strategy and project management, in part as a result of strong advocacy of research from ‘strategy-as-practice’ and ‘projects-as-practice’ perspectives. Such perspectives provide holistic contextual information and reveal the evolutionary and responsive nature of project and strategy processes. As environments shift and become more complex, dynamic capabilities are required for projects to flourish. Normative project management approaches are being challenged and practice-based project portfolio management (PPM) research is emerging. Increasingly, PPM defines the space between strategy and project management, with a key project focus on temporality. There is a need for further development and encouragement of practice-based approaches in PPM research that are alert to the becoming of projects as spatial manifestations that unfold in (different conceptions of) time. We identify three themes in project and portfolio management research that employ practice-based and strategically anchored perspectives. We illustrate the trajectory of early work on strategy and the front end of projects through to the development and application of increasingly sophisticated theoretical perspectives in project portfolio management (PPM) research. The dynamic capabilities perspective is shown to provide a strong theoretical foundation for investigating PPM and its role in implementing and informing strategy through projects. Theoretically grounded and practice-based research represents the interplay between structure and practice, with these reciprocally and recursively shaping each other over time. Building on these examples we call for practice-based research in PPM, and we suggest a convergence of strategy-as-practice perspectives and practice-based PPM research.
Kim, J, Cheng, J & Shim, H 1970, 'Efficient Graph-SLAM optimization using unit dual-quaternions', 2015 12th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), 2015 12th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), IEEE, IEEE, pp. 34-39.
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Kim, J, Cheng, J & Shim, H 1970, 'Unit dual-quaternion parametrisation for graph SLAM', Australasian Conference on Robotics and Automation, ACRA.
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This paper presents a new parameterisation approach for the graph-based SLAM problem utilising unit dual-quaternion. The rigid-body transformation typically consists of the robot position and rotation, and due to the Lie-group nature of the rotation, a homogeneous transformation matrix (HTM) has been widely used in pose-graph optimizations. In this paper, we investigate the use of unit dual-quaternion (UDQ) for SLAM problem, providing a unified representation of the robot poses with computational and storage benefits. Although UDQ has been widely used in kinematics and navigation (known as Michel Chasles' theorem or Skrew motion), it has not been well utilised in the graph SLAM optimisation. In this work, we re-parameterise the graph SLAM problem using UDQs, focusing on the optimisation performance and the sensitivity to poor initial estimates. Experimental results on public synthetic and real-world datasets show that the proposed approach significantly reduces the computational complexity, whilst retaining the similar accuracies compared to the HTM-based one. With the poor initial estimates, it is also shown that the rotation vector-based perturbation is more stable than the quaternion-based in recovering the error dual-quaternion.
Kim, S & Kim, J 1970, 'GPmap: A Unified Framework for Robotic Mapping Based on Sparse Gaussian Processes', Proceedings of Field and service robotics, Springer International Publishing, Springer, Cham, pp. 319-332.
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Kim, S & Kim, J 1970, 'Hierarchical Gaussian processes for robust and accurate map building', Australasian Conference on Robotics and Automation, ACRA, pp. 117-124.
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This paper proposes a new method for building occupancy maps and surface meshes using hierarchical Gaussian processes. Previously, we found that a Gaussian process, one of the state-of-The-Art machine learning techniques for regression and classification, could serve a unified framework for occupancy mapping and surface reconstruction. Particularly, due to its high computational complexity, we partitioned both training and test data into manageable subsets and applied local Gaussian processes. However, when the local regions do not include any observations, this approach makes no predictions and thus generates blanks in the map. Therefore, in order to deal with missing data and make it more robust, we combine a global Gaussian process with local Gaussian processes. The global Gaussian process covers the overall trend of the whole observations, while the local Gaussian processes adapt to precise local observations. We demonstrate our method with a real dataset and compare accuracy and speed with OctoMaps and our previous method, GPmaps. Experimental results show that our method is relatively slow than the previous work but produces more robust and accurate robotic maps.
Kong, FH, Boudali, AM & Manchester, IR 1970, 'Phase-indexed ILC for control of underactuated walking robots', 2015 IEEE Conference on Control Applications (CCA), 2015 IEEE Conference on Control Applications (CCA), IEEE, pp. 1467-1472.
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We propose a method for learning the nominal control input for virtual-constraints-based walking robots. The key problem in applying iterative learning control (ILC) to these systems is that the iterations are only approximately periodic. We develop a modified form of ILC that indexes previous iterations by a phase variable (a function of the state variables) rather than time. We show in experiments that the proposed method outperforms time-indexed ILC and a hybrid 'resetting' form of ILC in terms of tracking error reduction and stability.
Liu, H & Kim, J 1970, 'Decoupled trajectory tracking controllers design for multirotors', Australasian Conference on Robotics and Automation, ACRA.
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A controller design method is pro- posed to control quadrotors with six degrees of freedom. The vehicle sys-Tem is divided into four subsystems: The longitudinal, lateral, yaw, and height subsystems. A linear and de- coupled nominal model is obtained for each subsystem, while coupling and nonlinear dynamics, parametric perturbations, and external disturbances are considered as uncertainties. For each subsystem, a decoupled robust controller is proposed. Although there exist couplings between each channel, the output tracking errors of the four subsystems are proven to ultimately converge into a-priori set neighbor- hood of the origin. Real-Time implementation results of the decoupled controller are given to demonstrate its viability.
Matsubara, T, Miro, JV, Tanaka, D, Poon, J, Sugimoto, K & IEEE 1970, 'Sequential Intention Estimation of a Mobility Aid User for Intelligent Navigational Assistance', 2015 24TH IEEE INTERNATIONAL SYMPOSIUM ON ROBOT AND HUMAN INTERACTIVE COMMUNICATION (RO-MAN), IEEE International Symposium on Robot and Human Interactive Communication, IEEE, Kobe, Japan, pp. 444-449.
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© 2015 IEEE. This paper proposes an intelligent mobility aid framework aimed at mitigating the impact of cognitive and/or physical user deficiencies by performing suitable mobility assistance with minimum interference. To this end, a user action model using Gaussian Process Regression (GPR) is proposed to encapsulate the probabilistic and nonlinear relationships among user action, state of the environment and user intention. Moreover, exploiting the analytical tractability of the predictive distribution allows a sequential Bayesian process for user intention estimation to take place. The proposed scheme is validated on data obtained in an indoor setting with an instrumented robotic wheelchair augmented with sensorial feedback from the environment and user commands as well as proprioceptive information from the actual vehicle, achieving accuracy in near real-time of ∼80%. The initial results are promising and indicating the suitability of the process to infer user driving behaviors within the context of ambulatory robots designed to provide assistance to users with mobility impairments while carrying out regular daily activities.
Muller, R, Sankaran, S, Drouin, N, Nikolova, N & Vaagasaar, AL 1970, 'The socio-cognitive space for linking horizontal and vertical leadership', Asia-Pacific Researchers in Organization Studies (APROS), Sydney.
Patten, T, Kassir, A, Martens, W, Douillard, B, Fitch, R & Sukkarieh, S 1970, 'A Bayesian Approach for Time-Constrained 3D Outdoor Object Recognition [Extended Abstract]', IEEE International Conference on Robotics and Automation, IEEE International Conference on Robotics and Automation, Seattle, USA.
PAUL, G, MAO, S, LIU, L & XIONG, R 1970, 'MAPPING REPETITIVE STRUCTURAL TUNNEL ENVIRONMENTS FOR A BIOLOGICALLY-INSPIRED CLIMBING ROBOT', Assistive Robotics, CLAWAR 2015: 18th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, WORLD SCIENTIFIC, Hangzhou, China, pp. 325-333.
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© 2015, World Scientific Publishing Co. Pte Ltd. All rights reserved. This paper presents an approach to using noisy and incomplete depth-camera datasets to detect reliable surface features for use in map construction for a caterpillar-inspired climbing robot. The approach uses a combination of plane extraction, clustering and template matching techniques to infer from the restricted dataset a usable map. This approach has been tested in both laboratory and real-world steel bridge tunnel datasets generated by a climbing robot, with the results showing that the generated maps are accurate enough for use in localisation and step trajectory planning.
Paul, G, Quin, P, To, AWK & Liu, D 1970, 'A sliding window approach to exploration for 3D map building using a biologically inspired bridge inspection robot', 2015 IEEE International Conference on Cyber Technology in Automation, Control, and Intelligent Systems (CYBER), 2015 IEEE International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER), IEEE, Shenyang, China, pp. 1097-1102.
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© 2015 IEEE. This paper presents a Sliding Window approach to viewpoint selection when exploring an environment using a RGB-D sensor mounted to the end-effector of an inchworm climbing robot for inspecting areas inside steel bridge archways which cannot be easily accessed by workers. The proposed exploration approach uses a kinematic chain robot model and information theory-based next best view calculations to predict poses which are safe and are able to reduce the information remaining in an environment. At each exploration step, a viewpoint is selected by analysing the Pareto efficiency of the predicted information gain and the required movement for a set of candidate poses. In contrast to previous approaches, a sliding window is used to determine candidate poses so as to avoid the costly operation of assessing the set of candidates in its entirety. Experimental results in simulation and on a prototype climbing robot platform show the approach requires fewer gain calculations and less robot movement, and therefore is more efficient than other approaches when exploring a complex 3D steel bridge structure.
Paul, G, Quin, P, Yang, C-HJ & Liu, D 1970, 'Key feature-based approach for efficient exploration of structured environments.', ROBIO, IEEE International Conference on Robotics and Biomimetics, IEEE, Zhuhai, China, pp. 90-95.
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© 2015 IEEE. This paper presents an exploration approach for robots to determine sensing actions that facilitate the building of surface maps of structured partially-known environments. This approach uses prior knowledge about key environmental features to rapidly generate an estimate of the rest of the environment. Specifically, in order to quickly detect key features, partial surface patches are used in combination with pose optimisation to select a pose from a set of nearest neighbourhood candidates, from which to make an observation of the surroundings. This paper enables the robot to greedily search through a sequence of nearest neighbour poses in configuration space, then converge upon poses from which key features can best be observed. The approach is experimentally evaluated and found to result in significantly fewer exploration steps compared to alternative approaches.
Piyathilaka, L & Kodagoda, S 1970, 'Affordance-map: Mapping human context in 3D scenes using cost-sensitive SVM and virtual human models.', ROBIO, IEEE International Conference on Robotics and Biomimetics, IEEE, Zhuhai, pp. 2035-2040.
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Robots are often required to operate in environments where humans are not present, but yet require the human context information for better human robot interaction. Even when humans are present in the environment, detecting their presence in cluttered environments could be challenging. As a solution to this problem, this paper presents the concept of affordance-map which learns human context by looking at geometric features of the environment. Instead of observing real humans to learn human context, it uses virtual human models and their relationships with the environment to map hidden human affordances in 3D scenes. The affordance-map learning problem is formulated as a multi label classification problem that can be learned using cost-sensitive SVM. Experiments carried out in a real 3D scene dataset recorded promising results and proved the applicability of affordance-map for mapping human context.
Poon, J, Miro, JV & Black, R 1970, 'A Passive Estimator of Functional Degradation in Power Mobility Device Users', PROCEEDINGS OF THE IEEE/RAS-EMBS INTERNATIONAL CONFERENCE ON REHABILITATION ROBOTICS (ICORR 2015), IEEE International Conference on Rehabilitation Robotics, IEEE, Singapore, pp. 997-1002.
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© 2015 IEEE. This paper documents the development of a passive technique for assessing a power mobility device user's driving proficiency during everyday driving activities outside formal assessment conditions by therapists. This is approached by first building a model by means of an Artificial Neural Network to infer longer-Term destinations for discretized bouts of travel, and subsequently drawing cues indicative of decline in driving proficiency for the duration of point-To-point navigation rather than relying on instantaneously calculated metrics. This resultant quantity, which we refer to as 'functional degradation', can then provide therapists with additional information concerning user health or serve as a leveraging parameter in combinatory shared-control mobility frameworks. Experiments conducted by able-bodied users subject to simulated noise scaled to varying degrees of functional degradation reveal a quantitative correlation between these longer-Term proficiency metrics and the magnitude of degradation experienced; a promising outcome that sets the scene for a larger-scale clinical trial.
Richards, D, Patten, T, Fitch, R, Ball, D & Sukkarieh, S 1970, 'User interface and coverage planner for agricultural robotics', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, ARAA, Canberra, Australia.
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Farmers are under growing pressure to increase production, a challenge that robotics has the potential to address. A possible solution is to replace large farm machinery with numerous smaller robots. However, with a large number of robots it will become increasingly time consuming for the farmer to monitor and control them all, hence the need for an effective user interface and automatic multi-robot coordination. This paper describes the design of a user interface and coverage planner suitable for controlling multiple robots for typical coverage style farm operations. The cross-platform user interface allows the farmer to specify their farm including fields, roads and docking stations. The coverage planner splits the workload between the robots and plans periodic docking. The results for the different multi-robot coverage strategies demonstrate the advantage of the robots sequentially moving between fields rather than freely moving between them. The multi-robot system has been used for a coverage task on a real farm for controlling two real robots and four simulated robots operating for two days.
Scales, J, Sankaran, S & Cameron, R 1970, 'Is the project management field suffering from methodological inertia? Looking for evidence in publications in a recently established journal', Procedings of EURAM 2015 (European Academy of Management) Conference., Annual Conference of the European Academy of Management, .EURAM, Warsaw, pp. 1-18.
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Project management (PM) researchers have traditionally used quantitative methods in theirresearch due to the origins of this practice-based discipline in defence and engineering.Although qualitative methods are starting to be used in PM research, most of the qualitativeresearch reported tends to use case studies. Recently, there has been a call for PM researchers touse more novel methods to increase the variety of methods used by the researcher in the fieldcontributing to its further development (Drouin, Muller and Sankaran 2013; Cameron, Sankaranand Scales 2015). A review of papers presented at the International Research Network onOrganizing by Projects (IRNOP) conference in Berlin in 2009 showed a surprising trend that paperspresented at these conferences used more qualitative methods in comparison with articlespublished in key PM journals. This paper analyses articles published over the past six years in acomparatively new PM journal, since its inception, to explore whether the new journal hasmotivated PM researchers to overcome their methodological inertia and broaden the variety ofresearch methods they use. A mixed methods prevalence study was undertaken on articlespublished in the International Journal of Managing Projects in Business (IJMPiB) from 2008 to2014 (n=265). The findings point to methodological inertia in the majority of research but also anunusually high proportion of the use of mixed methods. Future research is needed to add finergranularity to the analysis.
Shi, L, Sun, L, Vidal-Calleja, T & Miro, JV 1970, 'Kernel-specific Gaussian process for predicting pipe wall thickness maps', Australasian Conference on Robotics and Automation, ACRA, Australasian Conference on Robotics and Automation, AARA, Canberra, pp. 1-8.
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Data organised in 2.5D such as elevation and thickness maps has been extensively studied in the fields of robotics and geostatistics. These maps are typically a probabilistic 2D grid that stores an estimated value (height or thickness) for each cell. Modelling the spatial dependencies and making inference on new grid locations is a common task that has been addressed using Gaussian random fields. However, inference faraway from the training areas results quite uncertain, therefore not informative enough for some applications. The objective of this re- search is to model the status of a pipeline based on limited and sparse local assessments, predicting the likely condition on pipes that have not been inspected. A customised kernel for Gaussian Processes (GP) is proposed to capture the spatial correlation of the pipe wall thickness data. An estimate of the likely condition of non-inspected pipes is achieved by con-cretising GP to a multivariate Gaussian distribution and generating realisations from the distribution. The performance of this approach is evaluated on various thickness maps from the same pipeline, where data have been obtained by measuring the actual remaining wall thickness. The output of this work aims to serve as the input of a structural analysis for failure risk estimation.
Su, D, Miro, JV, Vidal-Calleja, T & IEEE 1970, 'Modelling In-Pipe Acoustic Signal Propagation for Condition Assessment of Multi-Layer Water Pipelines', PROCEEDINGS OF THE 2015 10TH IEEE CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS, IEEE Conference on Industrial Electronics and Applications, IEEE, Auckland, New Zealand, pp. 545-550.
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© 2015 IEEE. A solution to the condition assessment of fluid-filled conduits based on the analysis of in-pipe acoustic signal propagation is presented in this paper. The sensor arrangement consists of an acoustic emitter from which a known sonic pulse is generated, and a collocated hydrophone receiver that records the arrival acoustic wave at a high sampling rate. The proposed method exploits the influence of the surrounding environment on the propagation of an acoustic wave to estimate the condition of the pipeline. Specifically, the propagation speed of an acoustic wave is influenced by the hoop stiffness of the surrounding materials, a fact that has been exploited in the analysis of boreholes in the literature. In this work, this finding is extended to validate the analytical expression derived to infer the condition of uniform, axis-symmetric lined waterworks, a first step to ultimately be able to predict the remaining active life (time-to-failure) of pipelines with arbitrary geometries through finite element analysis (FEA). An investigation of the various aspects of the proposed methodology with typical pipe material and structures is presented to appreciate the advantages of modelling acoustic waves behaviours in fluid-filled cylindrical cavities for condition assessment of water pipelines.
Su, D, Miro, JV, Vidal-Calleja, T & IEEE 1970, 'Real-time Sound Source Localisation for Target Tracking Applications using an Asynchronous Microphone Array', PROCEEDINGS OF THE 2015 10TH IEEE CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS, IEEE Conference on Industrial Electronics and Applications, IEEE, Auckland, New Zealand, pp. 1266-1271.
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© 2015 IEEE. This paper presents a strategy for sound source localisation using an asynchronous microphone array. The proposed method is suitable for target tracking applications, in which the sound source with a known frequency is attached to the target. Conventional microphone array technologies require a multi-channel A/D converter for inter-microphone synchronization making the technology relatively expensive. In this work, the requirement of synchronization between channels is relaxed by adding an external reference audio signal. The only assumption is that the frequencies of the reference signal and the sound source attached to the target are fixed and known beforehand. By exploiting the information provided by the known reference signal, the Direction Of Arrival (DOA) of target sound source can be calculated in real-time. The key idea of the algorithm is to use the reference source to 'pseudo-align' the audio signals from different channels. Once the channels are 'pseudo-aligned', a dedicated DOA estimation method based on Time Difference Of Arrival (TDOA) can be employed to find the relative bearing information between the target sound source and microphone array. Due to the narrow band of frequency of target sound source, the proposed approach is proven to be robust to low signals-to-noise ratios. Comprehensive simulations and experimental results are presented to show the validity of the algorithm.
SU, D, VALLS MIRO, J & VIDAL-CALLEJA, T 1970, 'GRAPH-SLAM BASED CALIBRATION OF AN EMBEDDED ASYNCHRONOUS MICROPHONE ARRAY FOR OUTDOOR ROBOTIC TARGET TRACKING', Assistive Robotics, CLAWAR 2015: 18th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, WORLD SCIENTIFIC, Hangzhou, Zhejiang Province, China, pp. 641-648.
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© 2015, World Scientific Publishing Co. Pte Ltd. All rights reserved. This paper presents a strategy for sound source localisation using an embedded asynchronous microphone array for robotic target tracking application. Conventional microphone array technologies require a multi-channel A/D converter for inter-microphone synchronization making the technology relatively expensive. In our method, a synchronization free embedded asynchronous microphone array has released this requirement. The microphone array needs self calibration using graph-based SLAM method, which estimates starting time offset and clock difference/drift rate of each microphone channel using Gauss-Newton least square optimization. The proposed method is suitable for target tracking applications.
Su, D, Vidal-Calleja, T, Mins, JV & IEEE 1970, 'Simultaneous asynchronous microphone array calibration and sound source localisation', 2015 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS), IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Hamburg, Germany, pp. 5561-5567.
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© 2015 IEEE. In this paper, an approach for sound source localisation and calibration of an asynchronous microphone array is proposed to be solved simultaneously. A graph-based Simultaneous Localisation and Mapping (SLAM) method is used for this purpose. Traditional sound source localisation using a microphone array has two main requirements. Firstly, geometrical information of microphone array is needed. Secondly, a multichannel analog-to-digital converter is required to obtain synchronous readings of the audio signal. Recent works aim at releasing these two requirements by estimating the time offset between each pair of microphones. However, it was assumed that the clock timing in each microphone sound card is exactly the same, which requires the clocks in the sound cards to be identically manufactured. A methodology is hereby proposed to calibrate an asynchronous microphone array using a graph-based optimisation method borrowed from the SLAM literature, effectively estimating the array geometry, time offset and clock difference/drift rate of each microphone together with the sound source locations. Simulation and experimental results are presented, which prove the effectiveness of the proposed methodology in achieving accurate estimates of the microphone array characteristics needed to be used on realistic settings with asynchronous sound devices.
Sun, L, Vidal-Calleja, T & Miro, JV 1970, 'Bayesian fusion using conditionally independent submaps for high resolution 2.5D mapping', 2015 IEEE International Conference on Robotics and Automation (ICRA), 2015 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Seattle, Washington, United States, pp. 3394-3400.
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© 2015 IEEE. Typically 2.5D maps provide a compact and efficient representation of the environment. When sensor data is obtained from multiple sets of noisy measurements at differing resolutions, the problem of compounding this information together to provide an effective and efficient means of mapping is not trivial, particularly as the size of the environment increases. In this paper, we propose a general framework for integrating heterogeneous sensor data to obtain large-scale 2.5D probabilistic maps. Gaussian Processes are used to generate a prior map that learns the spatial correlation between nearby points. Bayesian data fusion is then employed to update these prior maps with new measurements from distinct sensor modalities. In order to deal with large scale data, a novel submapping strategy is introduced to perform the fusion step efficiently in dealing with large covariance matrices. Submaps are first marginalised from the learned correlated prior and then updated based on the property of conditional independence. Most notably, the technique lends itself to generate accurate estimates at arbitrary resolutions and is able to handle varying noise from disparate sensor sources. The framework is applied to pipeline thickness mapping, with experimental results in fusing a high-resolution sensor and a low-resolution sensor showing the ability of the proposed technique to capture spatial correlations to come up with more accurate results when compared with a naïve fusion approach.
Thiyagarajan, K, Kodagoda, S & IEEE 1970, 'SMART Monitoring of Surface Temperature and Moisture Content Using Multisensory Data Fusion', PROCEEDINGS OF THE 2015 7TH IEEE INTERNATIONAL CONFERENCE ON CYBERNETICS AND INTELLIGENT SYSTEMS (CIS) AND ROBOTICS, AUTOMATION AND MECHATRONICS (RAM), IEEE International Conference on Cybernetics and Intelligent Systems, IEEE, Siem Reap, Cambodia.
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This paper characterizes the practice of Infrared Thermopile array sensor to monitor the surface temperature and also temperatures at different depth levels by employing the thermocouple probes. The increase in moisture content when the surface of the object is in influence with water bath is studied and interpreted. The effect of distances and depth levels between the electrodes on resistance moisture content has been analysed and Gaussian Process based machine learning technique to estimate the moisture content using resistive sensor data is proposed. The paper concludes by discussing the projected method's potential to augment the monitoring capabilities in sewer environment through multisensory data fusion.
Tran, A, Liu, D, Ranasinghe, R, Carmichael, M & Liu, C 1970, 'Analysis of Human Grip Strength in Physical Human Robot Interaction', Procedia Manufacturing, Conference on Applied Human Factors and Ergonomics, Elsevier BV, Las Vegas, pp. 1442-1449.
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© 2015 The Authors The purpose of this paper is to explore how an operator's grip plays a role in physical Human Robot Interaction (pHRI). By considering how the operator reacts to or initiates changes in control, it is possible to study the operator's grip pattern. By analyzing the grip pattern, it is possible to incorporate their natural response in order to create safer and more intuitive interfaces. An experiment where an exoskeleton and human collaborate in order to complete a path following task has been chosen to measure the forces applied by the user at the handle to observe the interaction between the operator and robot. AThruMode Matrix Array sensor has been wrapped around the robot's handle to measure the applied pressure. By introducing the sensor it not only enables the measurement of applied forces and how they are applied but also a measure of how tight the user is gripping the handle. Previous studies show that the natural response of a human to an unexpected event is to tighten their grip, indicating that how an operator grasps the handle can be related to the operator's intention. In order to investigate how the operator's grip of the handle changes, the experiments presented in this paper examine two different scenarios which might occur during an interaction, the first where the robot attempts to deviate from the path and the second where the operator wishes to deviate to a new path. The results of the experiments show that whether the operator or the robot initiates the transition, a measurable change in how the operator grasps the handle. The information in this paper can lead to new applications in pHRI by exploring the possible uses of an operator's grasping strength.
Virgona, A, Kirchner, N & Alempijevic, A 1970, 'Sensing and perception technology to enable real time monitoring of passenger movement behaviours through congested rail stations', ATRF 2015 - Australasian Transport Research Forum 2015, Proceedings, Australasian Transport Research Forum, ATRF, Sydney.
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© 2015 ATRF, Commonwealth of Australia. All rights reserved. Passenger behaviour can have a range of effects on rail operations from negative to positive. While rail service providers strive to design and operate systems in a manner that promotes positive passenger behaviour, congestion is a confounding factor, which can create responses that may undermine these efforts. The real time monitoring of passenger movement and behaviour through public transport environments including precincts, concourses, platforms and train vestibules would enable operators to more effectively manage congestion at a whole-of-station level. While existing crowd monitoring technologies allow operators to monitor crowd densities at critical locations and react to overcrowding incidents, they do not necessarily provide an understanding of the cause of such issues. Congestion is a complex phenomenon involving the movements of many people though a set of spaces and monitoring these spaces requires tracking large numbers of individuals. To do this, traditional surveillance technologies might be used but at the expense of introducing privacy concerns. Scalability is also a problem, as complete sensor coverage of entire rail station precinct, concourse and platform areas potentially requires a high number of sensors, increasing costs. In light of this, there is a need for sensing technology that collects data from a set of ‘sparse sensors’, each with a limited field of view, but which is capable of forming a network that can track the movement and behaviour of high numbers of associated individuals in a privacy sensitive manner. This paper presents work towards the core crowd sensing and perception technology needed to enable such a capability. Building on previous research using three-dimensional (3D) depth camera data for person detection, a privacy friendly approach to tracking and recognising individuals is discussed. The use of a head-to-shoulder signature is proposed to enable...
Virgona, A, Kirchner, N & Alempijevic, A 1970, 'Sensing and perception technology to enable real time monitoring of passenger movement behaviours through congested rail stations', ATRF 2015 - Australasian Transport Research Forum 2015, Proceedings.
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Passenger behaviour can have a range of effects on rail operations from negative to positive. While rail service providers strive to design and operate systems in a manner that promotes positive passenger behaviour, congestion is a confounding factor, which can create responses that may undermine these efforts. The real time monitoring of passenger movement and behaviour through public transport environments including precincts, concourses, platforms and train vestibules would enable operators to more effectively manage congestion at a whole-of-station level. While existing crowd monitoring technologies allow operators to monitor crowd densities at critical locations and react to overcrowding incidents, they do not necessarily provide an understanding of the cause of such issues. Congestion is a complex phenomenon involving the movements of many people though a set of spaces and monitoring these spaces requires tracking large numbers of individuals. To do this, traditional surveillance technologies might be used but at the expense of introducing privacy concerns. Scalability is also a problem, as complete sensor coverage of entire rail station precinct, concourse and platform areas potentially requires a high number of sensors, increasing costs. In light of this, there is a need for sensing technology that collects data from a set of ‘sparse sensors’, each with a limited field of view, but which is capable of forming a network that can track the movement and behaviour of high numbers of associated individuals in a privacy sensitive manner. This paper presents work towards the core crowd sensing and perception technology needed to enable such a capability. Building on previous research using three-dimensional (3D) depth camera data for person detection, a privacy friendly approach to tracking and recognising individuals is discussed. The use of a head-to-shoulder signature is proposed to enable association between sensors. Our efforts to improve the reli...
WANG, YUE, XIONG, R, HUANG, S & WU, JUN 1970, 'MULTI-SESSION SLAM OVER LOW DYNAMIC WORKSPACE USING RGBD SENSOR', Assistive Robotics, CLAWAR 2015: 18th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, WORLD SCIENTIFIC, Hangzhou, China, pp. 633-640.
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© 2015, World Scientific Publishing Co. Pte Ltd. All rights reserved. Climbing robot, flying robot or human wearable devices usually execute daily tasks in a pre-defined workspace sharing with humans. Long-term operation for these robots posts three challenge: 3D pose estimation, cost limitation and unexpected low dynamics. To address these challenges, we propose a solution for performing multi-session SLAM using a RGBD sensor. The main model is a multi-session pose graph, which evolves over the multiple visits of the workspace. When the robot explores the new areas, its poses will be added to the graph. The poses in the graph will be pruned if their corresponding 3D point scans are out of date. Thus the scans corresponding to the poses kept in the current graph will always give a map of the latest environment. To detect the changes of the environment, an out-of-dated scans identification module is proposed. Pruning of the poses also decreases the computational burden in graph optimization. Experimental results using real world data acquired by a Kinect sensor show that the proposed framework is able to manage the map in date for low dynamic environments with a reduction in complexity and an acceptable error level compared to the method saving all poses.
Wijerathna, B, Kodagoda, S, Miro, JV & Dissanayake, G 1970, 'Iterative coarse to fine approach for interpretation of defect profiles using MFL measurements', 2015 IEEE 10th Conference on Industrial Electronics and Applications (ICIEA), 2015 IEEE 10th Conference on Industrial Electronics and Applications (ICIEA), IEEE, Auckland, New Zealand, pp. 1099-1104.
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© 2015 IEEE. Magnetic Flux Leakage (MFL) is a commonly used technology for non destructive evaluation of ferromagnetic materials. MFL in general is used to estimate isolated defect geometry. In this study, a coarse to fine approach is proposed to interpret MFL measurements for continuous defect profiling. The coarse solution is implemented using a Gaussian Processes (GP) model and the fine approach is implemented using an unconstrained non-linear optimiser. This framework was tested on a 100 year old 600mm diameter cast iron pipe line. Some pipe sections were extracted, grit blasted and profiled using a sub millimetre accurate 3 - D laser scanner. The coarse to fine predictions were compared with the laser measured ground truth with just 1.2 mm RMS error.
Wu, K, Ranasinghe, R & Dissanayake, G 1970, 'Active recognition and pose estimation of household objects in clutter', 2015 IEEE International Conference on Robotics and Automation (ICRA), 2015 IEEE International Conference on Robotics and Automation (ICRA), IEEE, Seattle, pp. 4230-4237.
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© 2015 IEEE. This paper presents an active object recognition and pose estimation system for household objects in a highly cluttered environment. A sparse feature model, augmented with the characteristics of features when observed from different viewpoints is used for recognition and pose estimation while a dense point cloud model is used for storing geometry. This strategy makes it possible to accurately predict the expected information available during the Next-Best-View planning process as both the visibility as well as the likelihood of feature matching can be considered simultaneously. Experimental evaluations of the active object recognition and pose estimation with an RGB-D sensor mounted on a Turtlebot are presented.
