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International Conference on computer Science & Education (ICCSE)

作者： Fei Zhao Wuyi Yu Maoqing Li Xin Li Department of Automation Xiamen University Xiamen China Department of Electrical & Computer Engineering and Center for Computation & Technology Louisiana State University Baton Rouge USA

We present a volumetric texture synthesis technology that interpolates the interior solid texture from the boundary surface texture mapping. The interpolation is based on the (poly-)cube mapping and fundamental solution method. The (poly-)cube texture map indicates the boundary constraint for the fundamental solution, which then computes two harmonic scalar fields coherent to this boundary configuration. Given a solid geometric object with a closed genus-0 boundary surface, we first map the boundary surface onto a (poly-)cube; then compute the mapping from the (poly-)cube to the 2-dimensional texture coordinates space; finally use this as the boundary condition to compute harmonic volumetric fields for interpolating the interior solid texture. We demonstrate the effectiveness of this algorithm in isotropic 3D texture synthesis.

关键词： Solids Shape Interpolation Surface texture Educational technology computational modeling Medical simulation Geometry computer science computer science education

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Modal analysis and coupling in metal-insulator-metal waveguides

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Physical Review B 2009年第3期79卷 035120-035120页

作者： Şükrü Ekin Kocabaş Georgios Veronis David A. B. Miller Shanhui Fan Ginzton Laboratory Stanford University Stanford California 94305 USA Department of Electrical and Computer Engineering and Center for Computation and Technology Louisiana State University Baton Rouge Louisiana 70803 USA

This paper shows how to analyze plasmonic metal-insulator-metal waveguides using the full modal structure of these guides. The analysis applies to all frequencies, particularly including the near infrared and visible spectrum, and to a wide range of sizes, including nanometallic structures. We use the approach here specifically to analyze waveguide junctions. We show that the full modal structure of the metal-insulator-metal (MIM) waveguides—which consists of real and complex discrete eigenvalue spectra, as well as the continuous spectrum—forms a complete basis set. We provide the derivation of these modes using the techniques developed for Sturm-Liouville and generalized eigenvalue equations. We demonstrate the need to include all parts of the spectrum to have a complete set of basis vectors to describe scattering within MIM waveguides with the mode-matching technique. We numerically compare the mode-matching formulation with finite-difference frequency-domain analysis and find very good agreement between the two for modal scattering at symmetric MIM waveguide junctions. We touch upon the similarities between the underlying mathematical structure of the MIM waveguide and the PT symmetric quantum-mechanical pseudo-Hermitian Hamiltonians. The rich set of modes that the MIM waveguide supports forms a canonical example against which other more complicated geometries can be compared. Our work here encompasses the microwave results but extends also to waveguides with real metals even at infrared and optical frequencies.

关键词： finite difference methods frequency-domain analysis MIM devices modal analysis optical waveguides plasmons Sturm-Liouville equation

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Redundant Data Transmission in control/Estimation Over Wireless Networks

Redundant Data Transmission in Control/Estimation Over Wirel...

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2009 American control Conference (ACC 2009)

作者： Alexandre Rodrigues Mesquita Joao Pedro Hespanha Girish Nair Center for Control Dynamical Systems and Computation University of California Santa Barbara CA 93106 Departament of Electrical and Electronic Engineering University of Melbourne VIC 3010 Australia

ISBN: (纸本)9781424445233

In wireless networks the probability of successful communication can be significantly increased by transmitting multiple copies of a same packet. Communication protocols that exploit this by dynamically assigning the number of transmitted copies of the same data can significantly improve the control performance in a networked control system with only a modest increase in the total number of transmissions. In this paper we develop techniques to design communication protocols that exploit multiple packets transmissions while seeking a balance between stability/estimation performance and communication rate. An average cost optimality criterion is employed to obtain optimal protocols. Optimal protocols are also obtained for networks whose nodes are subject to limited computation.

关键词： Wireless networks control performance data transmission redundant data Networked control systems Communication protocols protocols Transmissions transmission copying packet communications Ganglia

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$H_{\infty }$ Fuzzy control of Nonlinear Systems Under Unreliable Communication Links

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IEEE Transactions on Fuzzy Systems 2009年第2期17卷 265-278页

作者： Huijun Gao Yan Zhao Tongwen Chen Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin China Department of Electrical and Computer Engineering University of Alberta Edmonton AB Canada

This paper investigates the problem of H infin fuzzy control of nonlinear systems under unreliable communication links. The nonlinear plant is represented by a Takagi--Sugeno (T-S) fuzzy model, and the control strategy takes the form of parallel distributed compensation. The communication links existing between the plant and controller are assumed to be imperfect (that is, data packet dropouts occur intermittently, which appear typically in a network environment), and stochastic variables satisfying the Bernoulli random binary distribution are utilized to model the unreliable communication links. Attention is focused on the design of H infin controllers such that the closed-loop system is stochastically stable and preserves a guaranteed H infin performance. Two approaches are developed to solve this problem, based on the quadratic Lyapunov function and the basis-dependent Lyapunov function, respectively. Several examples are provided to illustrate the usefulness and applicability of the developed theoretical results.

关键词： Fuzzy systems Communication system control Fuzzy control control systems Nonlinear systems Lyapunov method Space technology Nonlinear control systems Fuzzy sets control design

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A probabilistic roadmap based planning algorithm for wheeled-tip robots manipulating polygonal objects

A probabilistic roadmap based planning algorithm for wheeled...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： N. Noori E. Noohi H. Moradi A. H. Bakhtiary M. Nili Ahmadabadi Robotics and AI Lab Control and Intelligent Processing Center Department of Electrical and Computer Engineering University of Tehran Tehran Iran

This work extends the probabilistic roadmap (PRM) framework by efficiently incorporating the force closure (FC) criterion into motion planning. A new FC verification approach is proposed that eliminates the need for testing FC in the intermediate configurations of the local planner. The algorithm is tested for special kinds of planar robots that have two wheeled-tip fingers. The wheels are actuated and can roll along the object's edges. We propose a general planning algorithm for this new mechanism without any limitations on the fingers structure and the task. The algorithm is implemented and the simulation results in ADAMS verify the validity of our algorithm.

关键词： Mobile robots Fingers Wheels Service robots Humanoid robots Intelligent robots Motion planning Testing Mechatronics Defense industry

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Speeding up top-down attention control learning by using full observation knowledge

Speeding up top-down attention control learning by using ful...

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IEEE International Symposium on computational Intelligence in Robotics and Automation (CIRA)

作者： N. Noori M. Nili Ahmadabadi M. S. Mirian B. N. Araabi AI Lab Control and Intelligent Processing Center of Excellence Department of Electrical and Computer Engineering University of Tehran Tehran Iran

ISBN: (纸本)9781424448081

We present a general mathematical description of the top-down attention control problem. Three important components are identified in the model: context extraction, attention focus and decision making. The context gives a coarse blurry representation of the whole input; the attention module models the focus of attention on a limited part of input, and the decision making component accounts the final decision of the agent for its motory actions. In order to achieve a faster convergence of attention learning in the online phase, an offline optimization step is performed in advance. To do so, we incorporate the knowledge of a full observer agent that has approximately learned the optimal decision making of the task. The simulation results show that by employing our algorithm, the learning speed is improved.

关键词： Context modeling Decision making Layout Focusing Convergence Information filtering Information filters Robot sensing systems Bayesian methods Humans

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Benchmark Tests of Active Disturbance Rejection control on an Industrial Motion control Platform

Benchmark Tests of Active Disturbance Rejection Control on a...

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2009 American control Conference (ACC 2009)

作者： Gang Tian Zhiqiang Gao Center for Advanced Control Technologies Department of Electrical and Computer Engineering Cleveland State University Cleveland OH 44115 USA

ISBN: (纸本)9781424445233

The improvement of Active Disturbance Rejection control over the existing industry controller is benchmarked with the state of the art industrial automation equipment, using the common PLC, drive, and the mechanical transmissions of belt, gear, and direct coupling. All together 168 tests are run at various line speeds, different levels of pulse-like torque disturbance, and with various viscous friction. The results are tabulated for comparison, in terms of integrated absolute error and maximum error observed, and the RMS and peak torque required from the drive motor. In the worst case scenarios, across all variations of mechanical configuration, we observe the performance improvement from just under 20percent to 290percent, with comparable control efforts. Together with simplicity in the control algorithm itself, the ease of tuning and operation, such improvement establishes ADRC as a viable replacement of the existing industry controller in manufacturing.

关键词： Robust control Benchmark testing state of the art disturbing torque Machine Configuration MECHANICAL TRANSMISSIONS computer algorithms performance boost Motor control absolute error directly coupled DC motors maximum error peak torque BENCHMARKS

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Fuzzy controller for cooperative object pushing with variable line contact

Fuzzy controller for cooperative object pushing with variabl...

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International Conference on Mechatronics (ICM)

作者： Mahsa Aliakbar Golkar Sarah Taghavi Namin Hossein Aminaiee Control and Intelligent Processing Center of Excellence Robotics and AI Laboratory Department of Electrical and Computer Engineering University of Tehran Iran

Designing an appropriate cooperation protocol in multi-robot systems such as multi-robot object manipulation systems is a challenging task. In this paper designing and implementing a cooperation protocol between two robots pushing an object toward an arbitrary goal configuration is investigated. The proposed method benefits from task decoupling which simplifies the cooperation protocol design. Each robot gets its proper action from a particular fuzzy inference system independently. The fuzzy controllers outputs are low-level robot commands by which the need to a robot path planning algorithm is eliminated. Simulation results show that robots could push the object to the goal configuration cooperatively. Experiments have been conducted to approve the proposed system.

关键词： Fuzzy control Robot kinematics Protocols Fuzzy systems Electric variables control control systems Multirobot systems Path planning Inference algorithms Mobile robots

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From Poncelet's Invariance Principle to Active Disturbance Rejection

From Poncelet's Invariance Principle to Active Disturbance R...

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2009 American control Conference (ACC 2009)

作者： Gang Tian Zhiqiang Gao Center for Advanced Control Technologies Department of Electrical and Computer Engineering Cleveland State University Cleveland OH 44115 USA

ISBN: (纸本)9781424445233

This is a brief survey of a little known field of disturbance estimation and subsequent cancellation, a field with a long history and is still rather disorganized. Researchers and results are scattered over almost two centuries, across East and West: from Jean-Victor Poncelet's Principle of Invariance in 1829, to Jingqing Han's conception of Active Disturbance Rejection in 1995 and beyond. But the field in recent years is maturing and coming into a focus with significant practical and theoretical implications abound. It provides a powerful alternative to the modern control paradigm in how real world control problems, of which disturbance rejection is a central theme, are viewed and solved. In this paper a reader will find a brief history of ideas, a new, unifying, problem formulation, and a summary of recent stability analysis results.

关键词： Disturbance rejection invariance Problem Formulation Stability analysis Maturity modern control

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Attenuation of ultrasound pressure fields described via contrast source formulation

Attenuation of ultrasound pressure fields described via cont...

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2009 IEEE International Ultrasonics Symposium, IUS 2009

作者： Demi, L. Verweij, M.D. Huijssen, J. De Jong, N. Van Dongen, K.W.A. Laboratory of Acoustical Imaging and Sound Control Faculty of Applied Sciences Delft University of Technology Netherlands Laboratory of Electromagnetic Research Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technology Netherlands Laboratory of Experimental Echocardiography Erasmus Medical Center Rotterdam Netherlands

ISBN: (纸本)9781424443895

Experimental data reveal that attenuation is an important phenomenon in medical ultrasound. The phenomenon is of particular importance for applications based on nonlinear propagation, as the higher frequency components of the pressure field generally experience greater attenuation. Therefore a method that is capable of modeling attenuation accurately is essential. In this paper we present a method to model attenuation via a contrast source formulation. We compare the obtained results with a version of the INCS method in which the attenuation is included in the Green's function. Both results are in excellent agreement with each other. ©2009 IEEE.

关键词： Ultrasonics

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