A time slotted multiple access scheme that shares bandwidth between source and training signals is proposed for the transmission of variable bit rate (VBR) video signals over non-ideal channels. The error performance ...
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A time slotted multiple access scheme that shares bandwidth between source and training signals is proposed for the transmission of variable bit rate (VBR) video signals over non-ideal channels. The error performance is examined using finite state Markov chains that model both the VBR source traffic and the time variation of fading channels. The characteristic time-scale of the fade duration, the step-size parameter of the LMS equalizer training algorithm, and the number of training sequences allocated per time slot jointly influence the error performance. The consideration of the physical layer characteristics in the design of higher layer protocols enhances the performance of conventional application layer based preventive and reactive error control schemes. Simulation results for fast and slow fading channels show that the proposed channel access scheme can lead to an order of magnitude decrease in the bit error ratio if the combination of training overhead and step-size parameter are chosen judiciously with respect to the fading time-scale. In addition, the multiplexing efficiency of VBR encoded video is shown to be useful for limiting the channel access delays when training overhead is increased.
In this paper we analyze the occurrence of Hopf bifurcations in indirect field-oriented control of induction motors and derive guidelines for setting the PI speed loop controller in order to keep the bifurcations far ...
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ISBN:
(纸本)0780352513
In this paper we analyze the occurrence of Hopf bifurcations in indirect field-oriented control of induction motors and derive guidelines for setting the PI speed loop controller in order to keep the bifurcations far enough from the operating conditions in the parameter space.
The eikonal equation and variants of it are of significant interest for problems in computer vision and image processing. It is the basis for continuous versions of mathematical morphology, stereo, shapefrom-shading a...
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The error and delay performance of variable bit rate (VBR) video transmission over non-ideal channels is examined using equalization schemes. The temporal correlation features of the fading signal and the source video...
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The error and delay performance of variable bit rate (VBR) video transmission over non-ideal channels is examined using equalization schemes. The temporal correlation features of the fading signal and the source video are modeled using finite state Markov chains. The source and training signals are multiplexed using a time slotted multiple access scheme. For slow-fading channels, the characteristic time-scale of the fade durations, the step-size parameter of the LMS equalizer training algorithm, and the number of training sequences allocated per time slot are found to jointly influence error performance. Simulation results show that the proposed channel access scheme can lead to an order of magnitude decrease in the bit error ratio if the combination of training overhead and step-size parameter are chosen judiciously with respect to the fading time-scale. In addition, the multiplexing efficiency of VBR encoded video is shown to be useful for limiting the channel access delays when the training overhead is increased.
A quantum computer is proposed in which information is stored in the two lowest electronic states of doped quantum dots (QD’s). Many QD’s are located in a microcavity. A pair of gates controls the energy levels in e...
A quantum computer is proposed in which information is stored in the two lowest electronic states of doped quantum dots (QD’s). Many QD’s are located in a microcavity. A pair of gates controls the energy levels in each QD. A controlled-NOT (C-NOT) operation involving any pair of QD’s can be effected by a sequence of gate-voltage pulses which tune the QD energy levels into resonance with frequencies of the cavity or a laser. The duration of a C-NOT operation is estimated to be much shorter than the time for an electron to decohere by emitting an acoustic phonon.
In this paper, we propose an robust controller design of rapid thermal processing (RTP) system using the structured uncertainty approach. Using the weighted mixed sensitivity function, we solve the robust stability pr...
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In this paper, we propose an robust controller design of rapid thermal processing (RTP) system using the structured uncertainty approach. Using the weighted mixed sensitivity function, we solve the robust stability problem against disturbance and temperature variation, and design a /spl mu/ controller using the curve fitting method against structured uncertainty. Finally, the simulation results are proposed to show the validity of the proposed method.
This paper describes the synthesis of robust and non-fragile H/sup /spl infin// state feedback controllers for linear systems with time delay and parameter uncertainties, and static state feedback controller with mult...
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This paper describes the synthesis of robust and non-fragile H/sup /spl infin// state feedback controllers for linear systems with time delay and parameter uncertainties, and static state feedback controller with multiplicative uncertainty. The sufficient condition of controller existence, the design method of robust and non-fragile H/sup /spl infin// state feedback controller, and the measure of non-fragility in controller are presented. Also, using some changes of variables and Schur complements, the obtained sufficient condition can be rewritten as an linear matrix inequality form in terms of transformed variables. Therefore, the obtained robust and non-fragile H/sup /spl infin// controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a degree.
This paper presents the problem of observer-based fuzzy H/sup /spl infin// control for a class of uncertain nonlinear systems with time-varying delayed systems on the basis of Takagi-Sugeno fuzzy model. First, we desi...
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ISBN:
(纸本)0780349903
This paper presents the problem of observer-based fuzzy H/sup /spl infin// control for a class of uncertain nonlinear systems with time-varying delayed systems on the basis of Takagi-Sugeno fuzzy model. First, we design a fuzzy observer such that destination error system is globally, exponentially stable. Next, we design a fuzzy H/sup /spl infin// controller such that the closed loop system is globally, exponentially stable and achieves L/sub 2/ gain performance. The fuzzy control systems utilize the concept of the so-called parallel distributed compensation. A sufficient condition for the existence of robust fuzzy H/sup /spl infin// controllers and observers are given in terms of linear matrix inequalities (LMIs). The control gains can also be directly obtained from the LMI solutions.
This work develops a sliding mode controller for the X-33 vehicle in launch and re-entry mode. The resulting controller utilizes two-loop sliding mode controller and provides robust, de-coupled tracking of both the re...
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The "nested" structure of the control system for the X33 vehicle in launch mode is developed. The outer loop (guidance) and the inner loop (rates) continuous sliding mode controllers are designed. Simulation...
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