84,971 research outputs found
Delay-dependent robust stability of stochastic delay systems with Markovian switching
No full textIn recent years, stability of hybrid stochastic delay systems, one of the important issues in the study of stochastic systems, has received considerable attention. However, the existing results do not deal with the structure of the diffusion but estimate its upper bound, which induces conservatism. This paper studies delay-dependent robust stability of hybrid stochastic delay systems. A delay-dependent criterion for robust exponential stability of hybrid stochastic delay systems is presented in terms of linear matrix inequalities (LMIs), which exploits the structure of the diffusion. Numerical examples are given to verify the effectiveness and less conservativeness of the proposed method
Enhancing delay fault coverage through low power segmented scan
No full textReducing power dissipation during test has been an active area of academic and industrial research for the last few years and numerous low power DFT techniques and test generation procedures have been proposed. Segmented scan [17-20] has been shown to be an effective technique in addressing test power issues in industrial designs [18]. To achieve higher shipped product quality, tests for delay faults are becoming essential components of manufacturing test. This paper demonstrates, for the first time, that segmented scan facilitates increased delay fault coverage without degrading the reduction of the switching activity obtained by segmented scan. The increased transition delay fault coverage is achieved through careful selection of the capture cycle application. Experimental results on larger ISCAS-89 benchmarks show that using three segments, on average, fault coverage using launch off capture can be increased by about 5.4% while simultaneously reducing the peak switching activity caused by capture cycles by over 30%
Dynamic Voltage Scaling Aware Delay Fault Testing
No full textThe application of Dynamic Voltage Scaling (DVS) to reduce energy consumption may have a detrimental impact on the quality of manufacturing tests employed to detect permanent faults. This paper analyses the influence of different voltage/frequency settings on fault detection within a DVS application. In particular, the effect of supply voltage on different types of delay faults is considered. This paper presents a study of these problems with simulation results. We have demonstrated that the test application time increases as we reduce the test voltage. We have also shown that for newer technologies we do not have to go to very low voltage levels for delay fault testing. We conclude that it is necessary to test at more than one operating voltage and that the lowest operating voltage does not necessarily give the best fault cover
A variable delay integrated receiver for differential phase-shift keying optical transmission systems
No full textAn integrated variable delay receiver for DPSK optical transmission systems is presented. The device is realized in silicon-on-insulator technology and can be used to detect DPSK signals at any bit-rates between 10 and 15 Gbit/s
Amplified Fiber-Optic Recirculating Delay Lines
No full textExperimental and theoretical results on single- and double-amplified recirculating delay lines are presented. One of our aims is to emphasize their application as filters, showing a wide flexibility of design. Analysis of their performance in the spectral and time domains have been carried out. A novel method of understanding the behavior of double structures has been developed and successfully tested with experimental results employing Er-doped fiber amplifiers as delay lines.Publicad
Delay differential equation models for real-time dynamic substructuring
No full textReal-time dynamic substructuring is a testing technique that models an entire system through the combination of an experimental test piece, representing part of the system, with a numerical model of the rest of the system. Delays can has a significant effect on the technique, as signals are passed between the two parts of the system in real-time. The focus of this paper is the influence of the delay on the dynamics of the substructured system. This is addressed using a linear example which may be described by a delay differential equation (DDE) model. This type of analysis allows critical delay values for system stability to be computed, which in turn can be used to help design the substructuring test system. Two methods are presented for the example considered. The first makes use of an analytical approach and the second of a numerical software tool, DDE-BIFTOOL. Normally, in substructuring tests, the actuators response time exceeds the critical delay time and the substructured system is unstable. It is demonstrated that the system can be stabilized using an adaptive delay compensation technique based on forward polynomial prediction. Finally we outline how these techniques may be applied to an industrial example of modelling a nonlinear spring
Delay-dependent exponential stability of neutral stochastic delay systems
No full textThis paper studies stability of neutral stochastic delay systems by linear matrix inequality (LMI) approach. Delay dependent criterion for exponential stability is presented and numerical examples are conducted to verify the effectiveness of the proposed method
Time Interference Alignment via Delay Offset for Long Delay Networks
No full textThe potential of Time Interference Alignment is investigated in this work, with particular reference to the attainable degrees of freedom. The K-user interference channel is considered, in which transmitters and receivers are placed randomly in a Euclidean space. A model for long delay networks is introduced and the degrees of freedom for different cases (with and without transmitter delay coordination) are evaluated. It is shown how time interference alignment can provide more dof than TDMA when the transmitters jointly coordinate their transmission delay and the number of pairs is K >=5. Closed form expressions are derived for several cases of interest which provide insight and useful predictions. This work is concluded with an investigation of the achievable degrees of freedom for multi-satellite networks, where it is shown that the results obtained under several assumptions do predict accurately the dof in a real setting
Stability implications of delay distribution for first-order and second-order systems
No full textIn application areas, such as biology, physics and engineering, delays arise naturally because of the time it takes for the system to react to internal or external events. Often a delay is not fixed but varies according to some distribution function. This paper considers the effect of delay distribution on the asymptotic stability of the zero solution of functional differential equations --- the corresponding mathematical models. We first show that the asymptotic stability of the zero solution of a first-order scalar equation with symmetrically distributed delay follows from the stability of the corresponding equation where the delay is fixed and given by the mean of the distribution. This result completes a proof of a stability condition in [Bernard, S., Belair, J. and Mackey, M. C. Sufficient conditions for stability of linear differential equations with distributed delay. Discrete Contin. Dyn. Syst. Ser. B, 1(2):233--256, 2001], which was motivated in turn by an application from biology. We also discuss the corresponding case of second-order scalar delay differential equations, because they arise in physical systems that involve oscillating components. An example shows that it is not possible to give a general result for the second-order case. Namely, the boundaries of the stability regions of the distributed-delay equation and of the mean-delay equation may intersect, even if the distribution is symmetric
Delay-dependent stabilization of stochastic interval delay systems with nonlinear disturbances
No full textThis is the post print version of the article. The official published version can be obtained from the link below - Copyright 2007 Elsevier Ltd.In this paper, a delay-dependent approach is developed to deal with the robust stabilization problem for a class of stochastic time-delay interval systems with nonlinear disturbances. The system matrices are assumed to be uncertain within given intervals, the time delays appear in both the system states and the nonlinear disturbances, and the stochastic perturbation is in the form of a Brownian motion. The purpose of the addressed stochastic stabilization problem is to design a memoryless state feedback controller such that, for all admissible interval uncertainties and nonlinear disturbances, the closed-loop system is asymptotically stable in the mean square, where the stability criteria are dependent on the length of the time delay and therefore less conservative. By using Itô's differential formula and the Lyapunov stability theory, sufficient conditions are first derived for ensuring the stability of the stochastic interval delay systems. Then, the controller gain is characterized in terms of the solution to a delay-dependent linear matrix inequality (LMI), which can be easily solved by using available software packages. A numerical example is exploited to demonstrate the effectiveness of the proposed design procedure.This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grant GR/S27658/01, the Nuffield Foundation of the UK under Grant NAL/00630/G, and the Alexander von Humboldt Foundation of Germany
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