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2010 IEEE International Ultrasonics Symposium

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

ISBN: (纸本)9781457703829

Research on nonlinear medical ultrasound has been increased over the last decade and has resulted in a wide range of numerical methods for the modeling of the nonlinear distortion of a propagating pressure wave. However, when applied to realistic configurations, the majority of these methods are either computationally expensive or limited by the applied approximations. The Iterative Nonlinear Contrast Source (INCS) method is able to accurately compute the pulsed nonlinear pressure wave field that is generated in a large three-dimensional domain by an arbitrary transducer transmitting under a large steering angle. The method is based on the Neumann iterative solution of a nonlinear integral equation that is equivalent to the Westervelt equation. To improve the performance of the method, it would be beneficial to employ iterative schemes (e.g. Conjugate Gradient based schemes) that are efficient for solving linear integral equations. This motivates the development of a linearized version of the INCS method, as presented in this paper. To test the presented approach, a Bi-CGSTAB scheme is used to solve the linearized Westervelt equation. For the one-dimensional case, results are obtained and compared with the solution obtained with the original INCS method, and the Fubini solution. All the results have been obtained up to the third harmonic component and are in agreement with each other.

关键词： Pressure waves nonlinearity Nonlinear distortion Integral equations Modeling Numerical methods Ultrasonic Waves Equation Medical

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Designs of Wireless Monitoring Network System of Mill

Designs of Wireless Monitoring Network System of Mill

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International Conference on Computational Intelligence and Software engineering (CiSE)

作者： Cheng Hao Zhanlin Wang Zhigang Yang Jianmin Wang Ling Yang NanoRobotics Laboratory Ecole Polytechnique de Montréal Montréal QC Canada College of Information and Control Engineering China University of Petroleum School of Computer Science and Engineering Nanjing University of Science and Technology 200 Xiaolingwei Road Nanjing China Electrical and Electronic Engineering School North China Electric Power University Tangshan China School of Computer Science and Engineering Jiangsu University of Science and Technology 2 Huancheng Road Zhenjiang China College of Computer and Automatic Control Hebei Polytechnic University Tangshan China

In this paper, sensors, which are directly installed on the surface of the mill, are used to collect mill's signals by wireless. The frame of the system is introduced and the hardware and software is designed in details in this paper. With the transmission mode of I 2 S and MCU of AT89S2051, the transform from analog signals to digital signals , data's transmission by wireless is achieved by this system. On this basis, the program designed is not only good at collect mill's signals, but also restraining the interference, analyzing spectrum. So the program can effectively achieve the mill state detection.

关键词： Wireless communication Wireless sensor networks Monitoring Hardware computers Clocks Sensors

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Threshold Quantum Secret Sharing of Secure Direct Communication

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Chinese Physics Letters 2009年第1期26卷 21-24页

作者：李宝奎杨宇光温巧燕 Department of Automatic Control School of Information Science and Technology Beijing Institute of Technology Beijing 100081 College of Computer Science and Technology Beijing University of Technology Beijing 100124 State Key Laboratory of Integrated Services Network Xidian University Xi'an 710071 State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876

We propose a （L, n）-threshold quantum secret sharing protocol of secure direct communication following some ideas of Zhang＇s protocol [Phys. Lett. A 342 （2005） 60] and Tokunaga et al.＇s protocol [Phys. Rev. A 71 （2005） 012314]. The sender distributes the classical secret shares to his or her n agents and each agent owns a secret share in advance. The sender＇s secure direct communication message can be extracted by an agent subset by collaboration in such a way that at least t or more agents can obtain the secret message with the mutual assistances but any t - 1 or fewer agents cannot. In contrast to the previous multiparty quantum secret sharing protocols in which the sender＇s secret message can be recovered only if all the agents collaborate, our protocol is more practical and more flexible.

关键词： QUANTUM communication computer network protocols DIGITAL communications MESSAGE theory (Communication) MATHEMATICAL physics WIRELESS communication systems

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Robust model predictive control of continuous-time sampled-data nonlinear systems with integral sliding mode 10

Robust model predictive control of continuous-time sampled-d...

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2009 10th European control Conference, ECC 2009

作者： Rubagotti, M. Raimondo, D.M. Ferrara, A. Magni, L. Dept. of Computer Engineering and Systems Science University of Pavia Via Ferrata 1 Pavia27100 Italy Automatic Control Laboratory Swiss Federal Institute of Technology Physikstrasse 3 Zürich8092 Switzerland

ISBN: (纸本)9783952417393

A hierarchical Nonlinear Model Predictive control (NMPC) scheme with guaranteed Input-to-State-practical-Stability (ISpS) is proposed. The controller is formed by an Integral Sliding Mode (ISM) controller and a NMPC one. The ISM, relying on the knowledge of the nominal continuous-time model of the system and of the piecewise constant control signal generated by the NMPC produces a control action aimed at reducing the difference between the dynamics of the nominal closed-loop system and the actual evolution of the state. The NMPC in this way can be designed based on a system with reduced uncertainty. In order to prove the stability of the overall control scheme, some general Regional ISpS results for continuous-time systems are proven. © 2009 EUCA.

关键词： Continuous time systems

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Spatial Distribution of Land Cover and Vegetation Activity along Topographic Gradient in an Arid River Valley, SW China

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Journal of Mountain Science 2009年第3期6卷 274-285页

作者： LIU Wen XU Xianli LUO Jiancheng SHEN Zhanfeng ZHONG Qiuhai Department of Automatic Control School of Automation Beijing Institute of Technology Beijing 100081 China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China Centre for Hydrology Micrometeorology and Climate Change Department of Civil and Environmental Engineering University College Cork Cork Ireland

Anthropogenic activities have become more and more important in characterizing the landscape, but their impacts are still restricted by natural environments. This paper discusses the interactions of anthropogenic activity, vegetation activity and topography through describing the spatial distribution of land cover and vegetation activity (represented by Normalized Difference Vegetation Index, NDVI) along topographic gradient in a mountainous area of southwestern China. Our results indicate that the existing landscape pattern is controlled by anthropogenic activities as well as topographic factors. Intensive anthropogenic activities mainly occur in areas with relatively low elevation, gentle and concave slopes, as these areas are easy and convenient to attain for human. Because of the destruction by human, some land cover types (mainly grassland and shrub) are only found in relatively harsher environments. This study also finds that topographic wetness index (W) used in other places only reflects runoff generation capacity, but not indicate the real spatial pattern of soil water content in this area. The relationships between NDVI and W, and NDVI and length slope factor (LSF) show that runoff and erosion have complex effects on vegetation activity. Greater values of W and LSF will lead to stronger capacity to produce runoff and transport sediment, and thereby increase soil water content and soil deposition, whereas beyond a certain threshold runoff and erosion are so strong that they would destruct vegetation growth. This study provides information needed to successfully restore native vegetation, improve land management, and promote sustainable development in mountainous areas, especially for developing regions.

关键词： Vertical distribution of land cover Anthropogenic activity Vegetation activity Environmental variability China

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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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Robust Model Predictive control of continuous-time sampled-data nonlinear systems with Integral Sliding Mode

Robust Model Predictive Control of continuous-time sampled-d...

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European control Conference (ECC)

作者： M. Rubagotti D.M. Raimondo A. Ferrara L. Magni Dept. of Computer Engineering and Systems Science University of Pavia Pavia Italy Automatic Control Laboratory Swiss Federal Institute of Technology Zürich Switzerland

关键词： Robustness Closed loop systems Uncertainty Stability analysis Economic indicators Manifolds Predictive control

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Learning Approaches to the Witsenhausen Counterexample From a View of Potential Games

Learning Approaches to the Witsenhausen Counterexample From ...

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Joint 48th IEEE Conference on Decision and control and 28th Chinese control Conference

作者： Na Li Jason R.Marden Jeff S.Shamma Department of Control and Dynamical Systems California Institute of Technology Social and Informational Sciences Laboratory California Institute of Technology School of Electrical and Computer Engineering Georgia Institute of Technology

Since Witsenhausen put forward his remarkable counterexample in 1968,there have been many attempts to develop efficient methods for solving this non-convex functional optimization *** there are few methods designed from game theoretic *** this paper,after discretizing the Witsenhausen counterexample and re-writing the formulation in analytical expressions,we use fading memory JSFP with inertia,one learning approach in games,to search for better controllers from a view of potential *** achieve a better solution than the previously known best ***,we show that the learning approaches are simple and automated and they are easy to extend for solving general functional optimization problems.

关键词： Learning Approaches to the Witsenhausen Counterexample From a View of Potential Games

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Enslavement and control of the multi DC-bus link voltages using adaptive fuzzy

Enslavement and control of the multi DC-bus link voltages us...

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International Symposium on Advanced Electromechanical Motion Systems & Electric Drives Joint Symposium (ELECTROMOTION)

作者： F. Bouchafaa D. Beriber M.S. Boucherit E.M. Berkouk Laboratory of Instrumentation Faculty of Electronics and Computer Engineering University of Sciences and Technology Houari Boumediene Algiers Algeria Laboratory of Process Control University of Algiers Algiers Algeria

Voltage-source multilevel inverters have become very attractive for power industries in power electronics applications during last years. The main purposes that have led to the development of the studies about multilevel inverters are the generation of output voltage signals with low harmonic distortion; the reduction of switching frequency. A serious constraint in a multilevel inverter is the capacitor voltage-balancing problem. The unbalance of different DC voltage sources of five-level neutral point clamping (NPC) voltage source inverter (VSI) constitutes the major limitation for the use of this new power converter. In order to stabilize these DC voltages, we propose in this paper to study the cascade constituted by three phases five-level PWM rectifier, a clamping bridge and five-level NPC (VSI). In the first part, we present a topology of five-level NPC VSI, then they propose a model of this converter and an optimal PWM strategy to control it using four bipolar carriers. Then in the second part, we study a five-level PWM rectifier, which is controlled by a multiband hysteresis strategy. In the last part of this paper, the authors study shows particularly the problem of the stability of the multi DC voltages of the inverter and its consequence on the performances of the induction motors (IM). Then, we propose a solution to the problem by employed closed loop regulation using PI regulator type fuzzy logic controller (FLC). The results obtained with this solution confirm the good performances of the proposed solution, and promise to use the inverter in high voltage and great power applications as electrical traction.

关键词： Voltage control Programmable control Adaptive control Fuzzy control Pulse width modulation inverters Pulse width modulation Clamps Rectifiers Power industry Power electronics

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Learning approaches to the Witsenhausen counterexample from a view of potential games

Learning approaches to the Witsenhausen counterexample from ...

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IEEE Conference on Decision and control

作者： Na Li Jason R. Marden Jeff S. Shamma Department of Control and Dynamical Systems California Institute of Technology Pasadena CA USA Social and Informational Sciences Laboratory California Institute of Technology Pasadena CA USA School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

ISBN: (纸本)9781424438716

Since Witsenhausen put forward his remarkable counterexample in 1968, there have been many attempts to develop efficient methods for solving this non-convex functional optimization problem. However there are few methods designed from game theoretic perspectives. In this paper, after discretizing the Witsenhausen counterexample and re-writing the formulation in analytical expressions, we use fading memory JSFP with inertia, one learning approach in games, to search for better controllers from a view of potential games. We achieve a better solution than the previously known best one. Moreover, we show that the learning approaches are simple and automated and they are easy to extend for solving general functional optimization problems.

关键词： Optical wavelength conversion Optimal control Cost function Random variables Optimization methods Design methodology Game theory Fading automatic control control systems

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