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Global automata: A new approach on modelling industrial systems

International Journal of Industrial and systems engineering 2008年第4期3卷 383-406页

作者： Deligiannis, Vasileios Manesis, Stamatis Lygeros, John Systems and Measurement Laboratory Department of Electrical and Computer Engineering University of Patras Rion-Patras 26500 Greece ETH Zurich Automatic Control Laboratory Physikstrasse 3 Zurich 8092 Switzerland

This paper introduces Global Automata as a new approach on modelling contemporary industrial systems. Global automata are based on automata philosophy and, as their name reveals, they constitute a super-set of existing automata types. Their implementation field is, therefore, wider in comparison with other available types. Their main characteristic is that they are especially oriented for industrial use. As regards to model architecture, they introduce new formulation parameters diversifying from conventional types, while they keep some common basic features. A formal definition of global automata is given as also two useful tools for system modelling, which are state aggregation and automata composition. Their use is illustrated with two representative industrial examples. © 2008, Inderscience Publishers.

关键词： Industrial engineering

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Rate and power allocation in fading multiple access channels

Rate and power allocation in fading multiple access channels

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6th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, Wiopt 2008

作者： ParandehGheibi, Ali Eryilmaz, Atilla Ozdaglar, Asuman Médard, Muriel Laboratory for Information and Decision Systems Electrical Engineering and Computer Science Department Massachusetts Institute of Technology Cambridge MA 02139 United States Electrical and Computer Engineering Ohio State University OH 43210 United States

ISBN: (纸本)9789639799189

We consider the problem of rate and power allocation in a fading multiple-access channel. Our objective is to obtain rate and power allocation policies that maximize a utility function defined over average transmission rates. In contrast with the literature, which focuses on the linear case, we present results for general concave utility functions. We consider two cases. In the first case, we assume that power control is possible and channel statistics are known. In this case, we show that the optimal policies can be obtained greedily by maximizing a linear utility function at each channel state. In the second case, we assume that power control is not possible and channel statistics are not available. In this case, we define a greedy rate allocation policy and provide upper bounds on the performance difference between the optimal and the greedy policy. Our bounds highlight the dependence of the performance difference on the channel variations and the structure of the utility function.

关键词： Power control

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Dynamic rate allocation in fading multiple access channels

Dynamic rate allocation in fading multiple access channels

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2008 Information Theory and Applications Workshop - ITA

作者： ParandehGheibi, Ali Eryilmaz, Aulla Ozdaglar, Asuman Médard, Muriel Laboratory for Information and Decision Systems Electrical Engineering and Computer Science Department Massachusetts Institute of Technology Cambridge MA 02139 United States Electrical and Computer Engineering Ohio State University OH 43210 United States

ISBN: (纸本)1424426707

We consider the problem of rate allocation in a fading Gaussian multiple-access channel (MAC) with fixed transmission powers. Our goal is to maximize a general concave utility function of transmission rates over the throughput capacity region. In contrast to earlier works in this context that propose solutions where a potentially complex optimization problem must be solved in every decision instant, we propose a low-complexity approximate rate allocation policy and analyze the effect of temporal channel variations on its utility performance. To the best of our knowledge, this is the first work that studies the tracking capabilities of an approximate rate allocation scheme under fading channel conditions. We build on an earlier work to present a new rate allocation policy for a fading MAC that implements a low-complexity approximate gradient projection iteration for each channel measurement, and explicitly characterize the effect of the speed of temporal channel variations on the tracking neighborhood of our policy. We further improve our results by proposing an alternative rate allocation policy for which tighter bounds on the size of the tracking neighborhood are derived. These proposed rate allocation policies are computationally efficient in our setting since they implement a single gradient projection iteration per channel measurement and each such iteration relies on approximate projections which has polynomial-complexity in the number of users.

关键词： Fading channels

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A Notion of Stochastic Input-to-State Stability and Its Application to Stability of Cascaded Stochastic Nonlinear systems

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Acta Mathematicae Applicatae Sinica 2008年第1期24卷 141-156页

作者： Shu-jun Liu Ji-feng Zhang Zhong-ping Jiang Department of Mathematics Southeast University Nanjing 210096 China Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China Department of Electrical and Computer Engineering Polytechnic University 5 Metrotech Center Brooklyfl N.Y. 11201 USA

In this paper, the property of practical input-to-state stability and its application to stability of cascaded nonlinear systems are investigated in the stochastic framework. Firstly, the notion of （practical） stochastic input-to-state stability with respect to a stochastic input is introduced, and then by the method of changing supply functions, （a） an （practical） SISS-Lyapunov function for the overall system is obtained from the corresponding Lyapunov functions for cascaded （practical） SISS subsystems.

关键词： Stochastic nonlinear systems Stochastic input-to-state stability （SISS） SISS-Lyapunov function

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Adaptive H∞ optimal control strategy based on nonminimal state space realization

Adaptive H∞ optimal control strategy based on nonminimal st...

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ASME International Mechanical engineering Congress and Exposition, IMECE 2007

作者： Yucelen, Tansel Pourboghrat, Farzad Embedded Control Systems Laboratory Southern Illinois University Carbondale United States Electrical and Computer Engineering Department Southern Illinois University Carbondale United States

ISBN: (纸本)0791843033

This paper presents a new adaptive H∞ optimal control algorithm for multiple-input multiple-output (MIMO) continuous-time linear systems, based on a new nonminimal state space realization (NSSR), using measured inputs and outputs, without differentation. The proposed methodology combines a recursive Kalman filter (RKF) parameter estimation algorithm, and a gradient-type neural network algorithm to approximate the solution to the algebraic Riccati-Matrix equation (ARME), which is essential to design the H∞ optimal control. Actual hardware experiments using a DSP have been carried out in order to verify the applicability and the performance of the proposed integrated modeling-control method for vibration control of a flexible plate system. Copyright © 2007 by ASME.

关键词： Optimal control systems

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Non-monotonic Lyapunov functions for stability of discrete time nonlinear and switched systems

Non-monotonic Lyapunov functions for stability of discrete t...

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IEEE Conference on decision and control

作者： Amir Ali Ahmadi Pablo A. Parrilo Laboratory for Information and Decision Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology USA

ISBN: (纸本)9781424431236

We relax the monotonicity requirement of Lyapunov¿s theorem to enlarge the class of functions that can provide certificates of stability. To this end, we propose two new sufficient conditions for global asymptotic stability that allow the Lyapunov functions to increase locally, but guarantee an average decrease every few steps. Our first condition is non-convex, but allows an intuitive interpretation. The second condition, which includes the first one as a special case, is convex and can be cast as a semidefinite program. We show that when non-monotonic Lyapunov functions exist, one can construct a more complicated function that decreases monotonically. We demonstrate the strength of our methodology over standard Lyapunov theory through examples from three different classes of dynamical systems. First, we consider polynomial dynamics where we utilize techniques from sum-of-squares programming. Second, analysis of piecewise affine systems is performed. Here, connections to the method of piecewise quadratic Lyapunov functions are made. Finally, we examine systems with arbitrary switching between a finite set of matrices. It will be shown that tighter bounds on the joint spectral radius can be obtained using our technique.

关键词： Lyapunov method Switched systems Polynomials Dynamic programming Linear systems Asymptotic stability Functional programming Nonlinear control systems control systems Sufficient conditions

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On training with feedback in wideband channels

On training with feedback in wideband channels

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IEEE International Conference on Ubiquitous Wireless Broadband (ICUWB)

作者： Sheng Jing Lizhong Zheng Muriel Medard Electrical Engineering and Computer Science Department and the Laboratory for Information and Decision Systems Massachusetts Institute of Technology Cambridge MA USA

Transmitter knowledge of channel state has a great impact on wideband fading channel capacity. However, in the low SNR regime, power per dimension does not suffice to provide an accurate measurement of the channel over the entire spectrum. In the presence of feedback, we may collect information at the transmitter about some aspects of the channel quality over a certain portion of the spectrum. In this work, we investigate the effect of such information. We consider channel testing with a finite amount of energy over a block-fading channel in both time and frequency. We consider a transmission scheme in which the wideband channel is decomposed into many parallel narrowband subchannels, each used with a binary modulation scheme. The quality of each subchannel corresponds to the crossover probability of a binary symmetric channel. We use a multi-armed bandit approach to consider the relative costs and benefits of allotting energy for testing versus transmission, and for repeated testing a single subchannel versus testing different subchannels. We give both upper and lower bounds on the number of subchannels that should be probed for throughput maximization under the scheme we have chosen. Our bounds are in terms of available transmission energy, available bandwidth and fading characteristics of the channel. Moreover, in our numerical results, the two bounds are close.

关键词： Testing Fading Transmitters Coherence Complexity theory Receivers Binary phase shift keying

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Robust source-seeking hybrid controllers for nonholonomic vehicles

Robust source-seeking hybrid controllers for nonholonomic ve...

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2008 American control Conference (ACC), vol.7

作者： Christopher G. Mayhew Ricardo G. Sanfelice Andrew R. Teel Center for Control Engineering and Computation Electrical and Computer Engineering Department University of California Santa Barbara CA USA Laboratory for Information and Decision Systems Massachusetts Institute of Technology MA USA

We develop a hybrid controller that drives a nonholonomic vehicle to the source of a radiation-like signal. The control signal depends only on measurements of the signal, which may be corrupted by noise, and internal states of the controller. The control strategy is inspired by a line minimization-based algorithm for unconstrained optimization of nonlinear functions without gradient information. We state the main properties of the algorithm and then discuss its implementation in a hybrid controller that coordinates the optimization algorithm with vehicle steering. We present semi-global practical convergence and stability results for the closed-loop system. These results are illustrated by simulation and experiment.

关键词： Robust control Remotely operated vehicles Mobile robots Noise measurement Convergence Vehicle driving Working environment noise Position measurement Tin Noise robustness

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Robust hybrid source-seeking algorithms based on directional derivatives and their approximations

Robust hybrid source-seeking algorithms based on directional...

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IEEE Conference on decision and control

ISBN: (纸本)9781424431236

A family of hybrid control algorithms is developed that steer a nonholonomic autonomous vehicle to the source of a scalar signal present in the environment. In an idealized setting, we develop a general hybrid control scheme that globally asymptotically stabilizes the vehicle position about the source. Pursuing a practical implementation, a series of perturbations to the family of controllers is introduced, resulting in a semi-global practical stability of the vehicle position about the source. An example of a recently developed conjugate direction-based controller fitting into this family is developed and demonstrated by simulation and experiment.

关键词： Robustness Remotely operated vehicles Mobile robots Robust control Stability Position measurement Noise measurement Working environment noise Chemical sensors Current measurement

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Information theory vs. queueing theory for resource allocation in multiple access channels

Information theory vs. queueing theory for resource allocati...

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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Ali ParandehGheibi Muriel Medard Asuman Ozdaglar Atilla Eryilmaz Laboratory for Information and Decision Systems Electrical Engineering and Computer Science Department Massachusetts Institute of Technology Cambridge MA USA Electrical and Computer Engineering Ohio State Uinversity OH USA

We consider the problem of rate allocation in a fading Gaussian multiple-access channel with fixed transmission powers. The goal is to maximize a general concave utility function of the expected achieved rates of the users. There are different approaches to this problem in the literature. From an information theoretic point of view, rates are allocated only by using the channel state information. The queueing theory approach utilizes the global queue-length information for rate allocation to guarantee throughput optimality as well as maximizing a utility function of the rates. In this work, we make a connection between these two approaches by showing that the information theoretic capacity region of a multiple-access channel and its stability region are equivalent. Moreover, our numerical results show that a simple greedy policy which does not use the queue-length information can outperform queue-length based policies in terms of convergence rate and fairness.

关键词： Information theory Queueing analysis Resource management Fading Throughput Channel state information Stability Multiaccess communication Laboratories Sampling methods

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