4,910 research outputs found

    Computational Methods for Cognitive and Cooperative Robotics

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    In the last decades design methods in control engineering made substantial progress in the areas of robotics and computer animation. Nowadays these methods incorporate the newest developments in machine learning and artificial intelligence. But the problems of flexible and online-adaptive combinations of motor behaviors remain challenging for human-like animations and for humanoid robotics. In this context, biologically-motivated methods for the analysis and re-synthesis of human motor programs provide new insights in and models for the anticipatory motion synthesis. This thesis presents the author’s achievements in the areas of cognitive and developmental robotics, cooperative and humanoid robotics and intelligent and machine learning methods in computer graphics. The first part of the thesis in the chapter “Goal-directed Imitation for Robots” considers imitation learning in cognitive and developmental robotics. The work presented here details the author’s progress in the development of hierarchical motion recognition and planning inspired by recent discoveries of the functions of mirror-neuron cortical circuits in primates. The overall architecture is capable of ‘learning for imitation’ and ‘learning by imitation’. The complete system includes a low-level real-time capable path planning subsystem for obstacle avoidance during arm reaching. The learning-based path planning subsystem is universal for all types of anthropomorphic robot arms, and is capable of knowledge transfer at the level of individual motor acts. Next, the problems of learning and synthesis of motor synergies, the spatial and spatio-temporal combinations of motor features in sequential multi-action behavior, and the problems of task-related action transitions are considered in the second part of the thesis “Kinematic Motion Synthesis for Computer Graphics and Robotics”. In this part, a new approach of modeling complex full-body human actions by mixtures of time-shift invariant motor primitives in presented. The online-capable full-body motion generation architecture based on dynamic movement primitives driving the time-shift invariant motor synergies was implemented as an online-reactive adaptive motion synthesis for computer graphics and robotics applications. The last chapter of the thesis entitled “Contraction Theory and Self-organized Scenarios in Computer Graphics and Robotics” is dedicated to optimal control strategies in multi-agent scenarios of large crowds of agents expressing highly nonlinear behaviors. This last part presents new mathematical tools for stability analysis and synthesis of multi-agent cooperative scenarios.In den letzten Jahrzehnten hat die Forschung in den Bereichen der Steuerung und Regelung komplexer Systeme erhebliche Fortschritte gemacht, insbesondere in den Bereichen Robotik und Computeranimation. Die Entwicklung solcher Systeme verwendet heutzutage neueste Methoden und Entwicklungen im Bereich des maschinellen Lernens und der kĂŒnstlichen Intelligenz. Die flexible und echtzeitfĂ€hige Kombination von motorischen Verhaltensweisen ist eine wesentliche Herausforderung fĂŒr die Generierung menschenĂ€hnlicher Animationen und in der humanoiden Robotik. In diesem Zusammenhang liefern biologisch motivierte Methoden zur Analyse und Resynthese menschlicher motorischer Programme neue Erkenntnisse und Modelle fĂŒr die antizipatorische Bewegungssynthese. Diese Dissertation prĂ€sentiert die Ergebnisse der Arbeiten des Autors im Gebiet der kognitiven und Entwicklungsrobotik, kooperativer und humanoider Robotersysteme sowie intelligenter und maschineller Lernmethoden in der Computergrafik. Der erste Teil der Dissertation im Kapitel “Zielgerichtete Nachahmung fĂŒr Roboter” behandelt das Imitationslernen in der kognitiven und Entwicklungsrobotik. Die vorgestellten Arbeiten beschreiben neue Methoden fĂŒr die hierarchische Bewegungserkennung und -planung, die durch Erkenntnisse zur Funktion der kortikalen Spiegelneuronen-Schaltkreise bei Primaten inspiriert wurden. Die entwickelte Architektur ist in der Lage, ‘durch Imitation zu lernen’ und ‘zu lernen zu imitieren’. Das komplette entwickelte System enthĂ€lt ein echtzeitfĂ€higes Pfadplanungssubsystem zur Hindernisvermeidung wĂ€hrend der DurchfĂŒhrung von Armbewegungen. Das lernbasierte Pfadplanungssubsystem ist universell und fĂŒr alle Arten von anthropomorphen Roboterarmen in der Lage, Wissen auf der Ebene einzelner motorischer Handlungen zu ĂŒbertragen. Im zweiten Teil der Arbeit “Kinematische Bewegungssynthese fĂŒr Computergrafik und Robotik” werden die Probleme des Lernens und der Synthese motorischer Synergien, d.h. von rĂ€umlichen und rĂ€umlich-zeitlichen Kombinationen motorischer Bewegungselemente bei Bewegungssequenzen und bei aufgabenbezogenen Handlungs ĂŒbergĂ€ngen behandelt. Es wird ein neuer Ansatz zur Modellierung komplexer menschlicher Ganzkörperaktionen durch Mischungen von zeitverschiebungsinvarianten Motorprimitiven vorgestellt. Zudem wurde ein online-fĂ€higer Synthesealgorithmus fĂŒr Ganzköperbewegungen entwickelt, der auf dynamischen Bewegungsprimitiven basiert, die wiederum auf der Basis der gelernten verschiebungsinvarianten Primitive konstruiert werden. Dieser Algorithmus wurde fĂŒr verschiedene Probleme der Bewegungssynthese fĂŒr die Computergrafik- und Roboteranwendungen implementiert. Das letzte Kapitel der Dissertation mit dem Titel “Kontraktionstheorie und selbstorganisierte Szenarien in der Computergrafik und Robotik” widmet sich optimalen Kontrollstrategien in Multi-Agenten-Szenarien, wobei die Agenten durch eine hochgradig nichtlineare Kinematik gekennzeichnet sind. Dieser letzte Teil prĂ€sentiert neue mathematische Werkzeuge fĂŒr die StabilitĂ€tsanalyse und Synthese von kooperativen Multi-Agenten-Szenarien

    Advances in Bio-Inspired Robots

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    This book covers three major topics, specifically Biomimetic Robot Design, Mechanical System Design from Bio-Inspiration, and Bio-Inspired Analysis on A Mechanical System. The Biomimetic Robot Design part introduces research on flexible jumping robots, snake robots, and small flying robots, while the Mechanical System Design from Bio-Inspiration part introduces Bioinspired Divide-and-Conquer Design Methodology, Modular Cable-Driven Human-Like Robotic Arm andWall-Climbing Robot. Finally, in the Bio-Inspired Analysis on A Mechanical System part, research contents on the control strategy of Surgical Assistant Robot, modeling of Underwater Thruster, and optimization of Humanoid Robot are introduced

    The Road Ahead for State Assessments

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    The adoption of the Common Core State Standards offers an opportunity to make significant improvements to the large-scale statewide student assessments that exist today, and the two US DOE-funded assessment consortia -- the Partnership for the Assessment of Readiness for College and Careers (PARCC) and the SMARTER Balanced Assessment Consortium (SBAC) -- are making big strides forward. But to take full advantage of this opportunity the states must focus squarely on making assessments both fair and accurate.A new report commissioned by the Rennie Center for Education Research & Policy and Policy Analysis for California Education (PACE), The Road Ahead for State Assessments, offers a blueprint for strengthening assessment policy, pointing out how new technologies are opening up new possibilities for fairer, more accurate evaluations of what students know and are able to do. Not all of the promises can yet be delivered, but the report provides a clear set of assessment-policy recommendations. The Road Ahead for State Assessments includes three papers on assessment policy.The first, by Mark Reckase of Michigan State University, provides an overview of computer adaptive assessment. Computer adaptive assessment is an established technology that offers detailed information on where students are on a learning continuum rather than a summary judgment about whether or not they have reached an arbitrary standard of "proficiency" or "readiness." Computer adaptivity will support the fair and accurate assessment of English learners (ELs) and lead to a serious engagement with the multiple dimensions of "readiness" for college and careers.The second and third papers give specific attention to two areas in which we know that current assessments are inadequate: assessments in science and assessments for English learners.In science, paper-and-pencil, multiple choice tests provide only weak and superficial information about students' knowledge and skills -- most specifically about their abilities to think scientifically and actually do science. In their paper, Chris Dede and Jody Clarke-Midura of Harvard University illustrate the potential for richer, more authentic assessments of students' scientific understanding with a case study of a virtual performance assessment now under development at Harvard. With regard to English learners, administering tests in English to students who are learning the language, or to speakers of non-standard dialects, inevitably confounds students' content knowledge with their fluency in Standard English, to the detriment of many students. In his paper, Robert Linquanti of WestEd reviews key problems in the assessment of ELs, and identifies the essential features of an assessment system equipped to provide fair and accurate measures of their academic performance.The report's contributors offer deeply informed recommendations for assessment policy, but three are especially urgent.Build a system that ensures continued development and increased reliance on computer adaptive testing. Computer adaptive assessment provides the essential foundation for a system that can produce fair and accurate measurement of English learners' knowledge and of all students' knowledge and skills in science and other subjects. Developing computer adaptive assessments is a necessary intermediate step toward a system that makes assessment more authentic by tightly linking its tasks and instructional activities and ultimately embedding assessment in instruction. It is vital for both consortia to keep these goals in mind, even in light of current technological and resource constraints.Integrate the development of new assessments with assessments of English language proficiency (ELP). The next generation of ELP assessments should take into consideration an English learners' specific level of proficiency in English. They will need to be based on ELP standards that sufficiently specify the target academic language competencies that English learners need to progress in and gain mastery of the Common Core Standards. One of the report's authors, Robert Linquanti, states: "Acknowledging and overcoming the challenges involved in fairly and accurately assessing ELs is integral and not peripheral to the task of developing an assessment system that serves all students well. Treating the assessment of ELs as a separate problem -- or, worse yet, as one that can be left for later -- calls into question the basic legitimacy of assessment systems that drive high-stakes decisions about students, teachers, and schools." Include virtual performance assessments as part of comprehensive state assessment systems. Virtual performance assessments have considerable promise for measuring students' inquiry and problem-solving skills in science and in other subject areas, because authentic assessment can be closely tied to or even embedded in instruction. The simulation of authentic practices in settings similar to the real world opens the way to assessment of students' deeper learning and their mastery of 21st century skills across the curriculum. We are just setting out on the road toward assessments that ensure fair and accurate measurement of performance for all students, and support for sustained improvements in teaching and learning. Developing assessments that realize these goals will take time, resources and long-term policy commitment. PARCC and SBAC are taking the essential first steps down a long road, and new technologies have begun to illuminate what's possible. This report seeks to keep policymakers' attention focused on the road ahead, to ensure that the choices they make now move us further toward the goal of college and career success for all students. This publication was released at an event on May 16, 2011

    Facilitating social collaboration in mobile cloud-based learning: a teamwork as a service (TaaS) approach

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    Mobile learning is an emerging trend that brings many advantages to distributed learners, enabling them to achieve collaborative learning, in which the virtual teams are usually built to engage multiple learners working together towards the same pedagogical goals in online courses. However, the socio-technical mechanisms to enhance teamwork performance are lacking. To meet this gap, we adopt the social computing to affiliate learners’ behaviors and offer them computational choices to build a better collaborative learning context. Combining the features of the cloud environment, we have identified a learning flow based on Kolb team learning experience to realize this approach. Such novel learning flow can be executed by our newly designed system, Teamwork as a Service (TaaS), in conjunction with the cloud-hosting learning management systems. Following this learning flow, learners benefit from the functions provided by cloud-based services when cooperating in a mobile environment, being organized into cloud-based teaching strategies namely “Jigsaw Classroom”, planning and publishing tasks, as well as rationalizing task allocation and mutual supervision. In particular, we model the social features related to the collaborative learning activities, and introduce a genetic algorithm approach to grouping learners into appropriate teams with two different team formation scenarios. Experimental results prove our approach is able to facilitate teamwork, while learners’ capabilities and preferences are taken into consideration. In addition, empirical evaluations have been conducted to show the improvement of collaborative learning brought by TaaS in real university level courses

    Swarm Robotics

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    Collectively working robot teams can solve a problem more efficiently than a single robot, while also providing robustness and flexibility to the group. Swarm robotics model is a key component of a cooperative algorithm that controls the behaviors and interactions of all individuals. The robots in the swarm should have some basic functions, such as sensing, communicating, and monitoring, and satisfy the following properties

    Applied Mathematics to Mechanisms and Machines

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    This book brings together all 16 articles published in the Special Issue "Applied Mathematics to Mechanisms and Machines" of the MDPI Mathematics journal, in the section “Engineering Mathematics”. The subject matter covered by these works is varied, but they all have mechanisms as the object of study and mathematics as the basis of the methodology used. In fact, the synthesis, design and optimization of mechanisms, robotics, automotives, maintenance 4.0, machine vibrations, control, biomechanics and medical devices are among the topics covered in this book. This volume may be of interest to all who work in the field of mechanism and machine science and we hope that it will contribute to the development of both mechanical engineering and applied mathematics

    Preventing premature convergence and proving the optimality in evolutionary algorithms

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    http://ea2013.inria.fr//proceedings.pdfInternational audienceEvolutionary Algorithms (EA) usually carry out an efficient exploration of the search-space, but get often trapped in local minima and do not prove the optimality of the solution. Interval-based techniques, on the other hand, yield a numerical proof of optimality of the solution. However, they may fail to converge within a reasonable time due to their inability to quickly compute a good approximation of the global minimum and their exponential complexity. The contribution of this paper is a hybrid algorithm called Charibde in which a particular EA, Differential Evolution, cooperates with a Branch and Bound algorithm endowed with interval propagation techniques. It prevents premature convergence toward local optima and outperforms both deterministic and stochastic existing approaches. We demonstrate its efficiency on a benchmark of highly multimodal problems, for which we provide previously unknown global minima and certification of optimality

    Development of Motion Control Systems for Hydraulically Actuated Cranes with Hanging Loads

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    Automation has been used in industrial processes for several decades to increase efficiency and safety. Tasks that are either dull, dangerous, or dirty can often be performed by machines in a reliable manner. This may provide a reduced risk to human life, and will typically give a lower economic cost. Industrial robots are a prime example of this, and have seen extensive use in the automotive industry and manufacturing plants. While these machines have been employed in a wide variety of industries, heavy duty lifting and handling equipment such as hydraulic cranes have typically been manually operated. This provides an opportunity to investigate and develop control systems to push lifting equipment towards the same level of automation found in the aforementioned industries. The use of winches and hanging loads on cranes give a set of challenges not typically found on robots, which requires careful consideration of both the safety aspect and precision of the pendulum-like motion. Another difference from industrial robots is the type of actuation systems used. While robots use electric motors, the cranes discussed in this thesis use hydraulic cylinders. As such, the dynamics of the machines and the control system designmay differ significantly. In addition, hydraulic cranes may experience significant deflection when lifting heavy loads, arising from both structural flexibility and the compressibility of the hydraulic fluid. The work presented in this thesis focuses on motion control of hydraulically actuated cranes. Motion control is an important topic when developing automation systems, as moving from one position to another is a common requirement for automated lifting operations. A novel path controller operating in actuator space is developed, which takes advantage of the load-independent flow control valves typically found on hydraulically actuated cranes. By operating in actuator space the motion of each cylinder is inherently minimized. To counteract the pendulum-like motion of the hanging payload, a novel anti-swing controller is developed and experimentally verified. The anti-swing controller is able to suppress the motion from the hanging load to increase safety and precision. To tackle the challenges associated with the flexibility of the crane, a deflection compensator is developed and experimentally verified. The deflection compensator is able to counteract both the static deflection due to gravity and dynamic de ection due to motion. Further, the topic of adaptive feedforward control of pressure compensated cylinders has been investigated. A novel adaptive differential controller has been developed and experimentally verified, which adapts to system uncertainties in both directions of motion. Finally, the use of electro-hydrostatic actuators for motion control of cranes has been investigated using numerical time domain simulations. A novel concept is proposed and investigated using simulations.publishedVersio

    Selected Papers from IEEE ICASI 2019

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    The 5th IEEE International Conference on Applied System Innovation 2019 (IEEE ICASI 2019, https://2019.icasi-conf.net/), which was held in Fukuoka, Japan, on 11–15 April, 2019, provided a unified communication platform for a wide range of topics. This Special Issue entitled “Selected Papers from IEEE ICASI 2019” collected nine excellent papers presented on the applied sciences topic during the conference. Mechanical engineering and design innovations are academic and practical engineering fields that involve systematic technological materialization through scientific principles and engineering designs. Technological innovation by mechanical engineering includes information technology (IT)-based intelligent mechanical systems, mechanics and design innovations, and applied materials in nanoscience and nanotechnology. These new technologies that implant intelligence in machine systems represent an interdisciplinary area that combines conventional mechanical technology and new IT. The main goal of this Special Issue is to provide new scientific knowledge relevant to IT-based intelligent mechanical systems, mechanics and design innovations, and applied materials in nanoscience and nanotechnology

    Biologically inspired evolutionary temporal neural circuits

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    Biological neural networks have always motivated creation of new artificial neural networks, and in this case a new autonomous temporal neural network system. Among the more challenging problems of temporal neural networks are the design and incorporation of short and long-term memories as well as the choice of network topology and training mechanism. In general, delayed copies of network signals can form short-term memory (STM), providing a limited temporal history of events similar to FIR filters, whereas the synaptic connection strengths as well as delayed feedback loops (ER circuits) can constitute longer-term memories (LTM). This dissertation introduces a new general evolutionary temporal neural network framework (GETnet) through automatic design of arbitrary neural networks with STM and LTM. GETnet is a step towards realization of general intelligent systems that need minimum or no human intervention and can be applied to a broad range of problems. GETnet utilizes nonlinear moving average/autoregressive nodes and sub-circuits that are trained by enhanced gradient descent and evolutionary search in terms of architecture, synaptic delay, and synaptic weight spaces. The mixture of Lamarckian and Darwinian evolutionary mechanisms facilitates the Baldwin effect and speeds up the hybrid training. The ability to evolve arbitrary adaptive time-delay connections enables GETnet to find novel answers to many classification and system identification tasks expressed in the general form of desired multidimensional input and output signals. Simulations using Mackey-Glass chaotic time series and fingerprint perspiration-induced temporal variations are given to demonstrate the above stated capabilities of GETnet
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