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OPTIMAL CONTROL FOR TWO-DIMENSIONAL LINEAR systems WITH VARIABLE COEFFICIENTS

Asian Journal of Control 2008年第4期1卷

作者： Jimshone Li Jason Sheng-Hong Tsai Leang-San Shieh Control System Laboratory Department of Electrical Engineering National Cheng Kung University Tainan 701 Taiwan R.O.C. Jim-Shone Li was born in Taiwan R. O.C. on April 20 1967. He received B.S. and M.S. degrees in Electrical Engineering from the Chung-Cheng Institute of Technology Taoyuan Taiwan R.O.C. in 1989 and 1993 respectively. He is currently a Ph.D. student at National Cheng-Kung University Tainan Taiwan R.O.C. His research interests include analysis and design of multidimensional systems and nonlinear system control. Department of Electrical and Computer Engineering University of Houston Houston TX 77004-4793 U.S.A.

An optimal control method for two-dimensional (2-D) linear systems with variable coefficients and free boundary conditions in Roesser's model is proposed in this paper. Based on Roesser's model, an equivalent general 1-D model of the 2-D system is presented, and the problem of minimizing a 2-D linear quadratic (LQ) cost function is solved for the case where complete state information is available. The solution is obtained by using the proposed dynamic programming in 1-D descriptor form to solve the Riccati equation and then arriving at the optimal control law and minimum cost. The proposed control methodology can be applied to discrete-time models of systems described by partial differential equations and can also be used in the field of signal processing.

关键词： Two-dimensional system optimal control Roesser's model Riccati equation

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Multi-Robot Localization and Mapping Strategy: Utilizing Behavior Based Dynamic Tree Structure and Observer-explorer Routine

Multi-Robot Localization and Mapping Strategy: Utilizing Beh...

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IEEE International Conference on Automation Science and engineering (CASE)

作者： Kevin K. Leung Garratt Gallagher Robotics Autonomous Systems and Controls Laboratory (RASCAL) Department of Mechanical and Aeronautical Engineering University of California Davis USA Department of Electrical and Computer Engineering Robotics Autonomus Systems and Control Laboratory (RASCAL) Department of Mechanical and Aeronautical Engineering University of California Davis USA

In this paper, we propose a simultaneous localization and map-building (SLAM) strategy to explore unknown environment. Multiple robots are deployed in unknown area and required to localize each other accurately while exploring. Instead of relying on active obstacle detector, we propose a method of exploration which uses only tactile sensors and inter-robot distance measurements. To avoid dead-reckoning and odometry errors, an observer-explorer based routine is adopted. A dynamic spanning tree structure is implemented for multi-robot coordination. Parent (observer) nodes monitor the distances of their children (explorer) nodes. In order to promote completeness of the map, the reconfigurable spanning tree structure favors unexplored area implicitly. An online behavior-based finite state machine drives the configuration of the structure. Our exploration scheme allows the differentiation between robots and obstacles or boundaries. When an obstacle or boundary is detected, it is recorded on a map that is shared with all other robots. The proposed strategy is simulated and results are presented.

关键词： Tree data structures Robot kinematics Robot sensing systems Simultaneous localization and mapping Robotics and automation Distance measurement Automata Service robots Global Positioning System Costs

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Algorithms and Hardware Structures for Unobtrusive Real-Time Compression of Instruction and Data Address Traces

Algorithms and Hardware Structures for Unobtrusive Real-Time...

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Data Compression Conference (DCC)

作者： Milena Milenkovic Aleksandar Milenkovic Martin Burtscher IBM Austin TX USA Electrical and Computer Engineering Department University of Alabama Huntsville USA Computer Systems Laboratory Cornell University Ithaca NY USA

Instruction and data address traces are widely used by computer designers for quantitative evaluations of new architectures and workload characterization, as well as by software developers for program optimization, performance tuning, and debugging. Such traces are typically very large and need to be compressed to reduce the storage, processing, and communication bandwidth requirements. However, preexisting general-purpose and trace-specific compression algorithms are designed for software implementation and are not suitable for runtime compression. Compressing program execution traces at runtime in hardware can deliver insights into the behavior of the system under test without any negative interference with normal program execution. Traditional debugging tools, on the other hand, have to stop the program frequently to examine the state of the processor. Moreover, software developers often do not have access to the entire history of computation that led to an erroneous state. In addition, stepping through a program is a tedious task and may interact with other system components in such a way that the original errors disappear, thus preventing any useful insight. The need for unobtrusive tracing is further underscored by the development of computer systems that feature multiple processing cores on a single chip. In this paper, we introduce a set of algorithms for compressing instruction and data address traces that can easily be implemented in an on-chip trace compression module and describe the corresponding hardware structures. The proposed algorithms are analytically and experimentally evaluated. Our results show that very small hardware structures suffice to achieve a compression ratio similar to that of a software implementation of gzip while being orders of magnitude faster. A hardware structure with slightly over 2 KB of state achieves a compression ratio of 125.9 for instruction address traces, whereas gzip achieves a compression ratio of 87.4. For data addr

关键词： Hardware Algorithm design and analysis Runtime computer aided instruction computer architecture Software debugging Software performance Design optimization Bandwidth Compression algorithms

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Opposition-Based Q(λ) with Non-Markovian Update

Opposition-Based Q(λ) with Non-Markovian Update

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IEEE Symposium on Adaptive Dynamic Programming and Reinforcement Learning, (ADPRL)

作者： Maryam Shokri Hamid R. Tizhoosh Mohamed S. Kamel Pattern Analysis and Machine Intelligence Laboratory Department of Systems Design Engineering University of Waterloo ONT Canada Department of Electrical and Computer Engineering University of Waterloo ONT Canada

The OQ(λ) algorithm benefits from an extension of eligibility traces introduced as opposition trace. This new technique is a combination of the idea of opposition and eligibility traces to deal with large state space problems in reinforcement learning applications. In our previous works the comparison of the results of OQ(λ) and conventional Watkins' Q(λ) reflected a remarkable increase in performance for the OQ(λ) algorithm. However the Markovian update of opposition traces is an issue which is investigated in this paper. It has been assumed that the opposite state can be presented to the agent. This may limit the usability of the technique to deterministic environments. In order to relax this assumption the non-Markovian opposition-based Q(λ) (NOQ(λ)) is introduced in this work. The new method is a hybrid of Markovian update for eligibility traces and non-Markovian-based update for opposition traces. The experimental results show improvements of learning speed for the proposed technique compared to Q(λ) and OQ(λ). The new technique performs faster than OQ(λ) algorithm with the same success rate and can be employed for broader range of applications since it does not require determining state transition

关键词： Learning Usability Dynamic programming Pattern analysis Machine intelligence Laboratories System analysis and design Design engineering systems engineering and theory State-space methods

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Sending the Most Recent Observation is not Optimal in Networked Control: Linear Temporal Coding and Towards the Design of a Control Specific Transport Protocol

Sending the Most Recent Observation is not Optimal in Networ...

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Proceedings of the 46th IEEE Conference on Decision and Control, Pages 4593-5051

作者： C. L. Robinson P. R. Kumar Department of Industrial and Enterprise Systems Engineering and the Coordinated Science Laboratory University of Illinois Urbana-Champaign USA Department of Electrical and Computer Engineering and the Coordinated Science Laboratory University of Illinois Urbana-Champaign USA

ISBN: (纸本)9781424414970;1424414970

This paper explores diversity of temporal observations in a networked control system or sensor network. We analyze what information should be sent between a sensor and a controller (or estimator) in a networked control system (or sensor network) where the two components are separated by an unreliable, bandwidth limited communication. Packets may be dropped at any time. Given a sensor of limited computational and storage capability restricted to transmitting linear combinations of measurements, we consider what should be transmitted following a packet drop - the most recent observation, the previously dropped observation, or a combination of the two? We show that the common practice of sending only the most recent observation is not optimal. We then derive necessary and sufficient conditions for an optimal linear combination of past and present observations. We address a special case where sensor bandwidth (or sampling rate) is higher than communication bandwidth (or throughput), and deal with the case of multiple dropped packets. These results suggest the design of a transport layer specific to networked control which optimizes packet contents contingent on previous packet loss. Alternatively, one could optimize access between contending sensors for a scarce communication medium. The results could be regarded as network coding across time. Simulations are used to illustrate the theoretical results.

关键词： transport protocols Networked control systems network control Sensor networks Sensors Packet Temporal finding Communications Media Linear Combination Bandwidth Packet loss sampling rate Network coding Optimal

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Optimal Control of Class of Non-linear Plants Using Artificial Immune systems: Application of the Clonal Selection Algorithm

Optimal Control of Class of Non-linear Plants Using Artifici...

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IEEE International Symposium on Intelligent Control (ISIC)

作者： S.A. Panimadai Ramaswamy G.K. Venayagamoorthy S.N. Balakrishnan Department of Electrical and Computer Engineering University of Missouri Rolla MO USA Real-Time Power and Intelligent Systems Laboratory Department of Electrical and Computer Engineering University of Missouri Rolla MO USA Department of Mechanical AeroSpace and Engineering Mechanics University of Missouri Rolla MO USA

The function of natural immune system is to protect the living organisms against invaders/pathogens. Artificial Immune System (AIS) is a computational intelligence paradigm inspired by the natural immune system. Diverse engineering problems have been solved in the recent past using AIS. Clonal selection is one of the few algorithms that belong to the family of AIS techniques. Clonal selection algorithm is the computational implementation of the clonal selection principle. The process of affinity maturation of the immune system is explicitly incorporated in this algorithm. This paper presents the application of AIS for the optimal control of a class of non-linear plants which are affine in control. The clonal selection algorithm is adapted for optimal control. A new mutation operator that operates on real values and one that aids in fast convergence is developed in this paper. AIS is used to obtain constant coefficient Kalman gain matrices. The validation and evaluation of the results thus obtained are carried out by comparing with standard and the widely used State Dependent Algebraic Riccati Equation (SDARE) method for the non-linear plants. In case of non-linear systems with hard state constraints, the SDARE formulation requires the use of mathematically involved expressions to incorporate these state constraints. However, the modified clonal selection algorithm developed in this paper has been used with hardly any changes to incorporate the hard state constraints and obtain the Kalman gain matrix.

关键词： Optimal control Artificial immune systems Immune system Kalman filters Riccati equations Protection Organisms Pathogens Computational intelligence systems engineering and theory

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GeoPPRA: An Energy-Efficient Geocasting Protocol in Mobile Ad Hoc Networks

GeoPPRA: An Energy-Efficient Geocasting Protocol in Mobile A...

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International Conference on networking (ICN)

作者： Paul Barom Jeon George Kesidis Networking Technology Laboratory Samsung Advanced Institute of Technology Yongin si Gyeonggi South Korea Department of Computer Science & Engineering and Electrical Engineering Pennsylvania State University University Park PA USA

In this paper, a variant of the conventional multicasting called geocasting, or location-based multicasting, is presented. The proposed scheme combines anycasting, restricted broadcasting, and local broadcasting to deliver packets to a group of nodes presented in a specific geographic region called geocast region. Also, the proposed scheme utilizes a pheromone-aided multipath algorithm (PPRA) to perform energy-efficient load balancing that increases the network lifetime. We compare the performance of GeoPPRA with well-known geocasting protocol GAMER via simulation. The simulation results show significant reductions of energy consumption, while maintaining comparable delivery ratio defined as the ratio of successfully delivered data packets to the total data packets sent from the source to one of the geocast group members.

关键词： Energy efficiency Mobile ad hoc networks Broadcasting Multicast protocols Load management Unicast Topology Energy consumption Routing protocols Global Positioning System

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Level-triggered control of a scalar linear system

Level-triggered control of a scalar linear system

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Mediterranean Conference on Control and Automation (MED)

作者： Maben Rabi John S. Baras Automatic Control Laboratory School of Electrical Engineering Royal Institute of Technology Stockholm Sweden Institute for Systems Research and Department of Electrical and Computer Engineering University of Maryland College Park MD USA

In networked control systems, because of limits on communication rates, control waveforms are frequently piece-wise constant with limits on rates at which they can switch levels. It is, therefore, natural to expect event-triggered control switchings to perform more efficiently than time-triggered ones. This article verifies the validity of this supposition. A method for designing good level-triggered control schemes is obtained by reducing the continuous time problem to one in discrete time. Then, by numerical procedures, the performance of the level-triggered scheme is computed for comparison with that of the periodically switched control scheme.

关键词： Control systems Linear systems Communication system control Automatic control Switches Communication switching Signal sampling Signal processing Laboratories Educational institutions

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Accurate Approximations for the Capacity Distribution of OFDM-Based Spatial Multiplexing

Accurate Approximations for the Capacity Distribution of OFD...

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IEEE International Conference on Communications (ICC)

作者： M. R. McKay P. J. Smith H. A. Suraweera I. B. Collings Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong China Department of Electrical and Computer Engineering University of Canterbury Christchurch New Zealand Department of Electrical and Computer Systems Engineering Monash University Melbourne Australia Wireless Technologies Laboratory ICT Centre CSIRO Sydney Australia

We derive new analytic approximations to the capacity distribution of frequency-selective Rayleigh fading MIMO channels. The results apply specifically to OFDM-based spatial multiplexing. In particular, we present a new closed-form Gaussian approximation which yields very high accuracy in many scenarios. For the low SNR regime, we also present a new simpler closed-form Gamma approximation, which we show to be even more accurate than Gaussian in this case. Our approximations are based on new exact closed-form expressions which we derive for the variance of the mutual information which, in contrast to previous results, apply for systems with both arbitrary numbers of antennas and arbitrary-length channel delay profiles.

关键词： MIMO Mutual information Gaussian approximation Information analysis OFDM Closed-form solution Receiving antennas Distributed computing Delay Analysis of variance

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PLASMA WAVES IN TWO-DIMENSIONAL ELECTRON systems AND THEIR APPLICATIONS

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International Journal of High Speed Electronics and systems 2007年第3期17卷 521-538页

作者： VICTOR RYZHII IRINA KHMYROVA MAXIM RYZHII AKIRA SATOU TAIICHI OTSUJI VLADIMIR MITIN MICHAEL S. SHUR Computer Solid State Physics Laboratory University of Aizu Aizu-Wakamatsu 965-8580 Japan Research Institute of Electrical Communication Tohoku University Sendai 980-8577 Japan Department of Electrical Engineering University at Buffalo SUNY Buffalo NY 14260 USA Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY 12180 USA

We overview the plasma properties of a two-dimensional electron gas in semiconductor heterostructures as well as new concepts and proposals of novel terahertz devices (detectors, sources utilizing plasma instabilities... 详细信息

关键词： Two-dimensional electron gas plasma oscillations terahertz detector oscillator and photomixer

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