Time filter

Source Type

Cergy, France

State bounding observation based on zonotopes is the subject of this paper. Dealing with zonotopes is motivated by set operations resulting in simple matrix calculations with regard to the often huge number of facets and vertices of the equivalent polytopes. Discrete-time LTV/LPV systems with state and measurement uncertainties are considered. Based on a new zonotope size criterion called FW-radius, and by merging optimal and robust observer gain designs, a Zonotopic Kalman Filter (ZKF) is proposed with a proof of robust convergence. The notion of covariation is introduced and results in an explicit bridge between the zonotopic set-membership and the stochastic paradigms for Kalman Filtering. No intersection is used and the influence of the reduction operator limiting to a tunable maximum the size of the matrices involved in the zonotopic set computations is fully taken into account in the LMI-based robust stability analysis. A numerical example illustrates the effectiveness of the proposed ZKF. © 2015 Elsevier Ltd. Source

Combastel C.,ENSEA Cergy
Asian Journal of Control

Recent advances in the design of interval observers have made it possible to ensure the non-divergence of the computed state bounds from the stability of LTI systems under bounded inputs, with no need for additional monotony assumptions. Time-varying changes of coordinates can be used to that purpose. Most of the related works result in either continuous-time or discrete-time interval dynamics. This paper proposes a constructive algorithm to compute the exact sampled response of a linear interval predictor under bounded inputs, gives a stability equivalence result and discusses the design of interval observers. The exact sampling requires held input bounds but the uncertain input itself needs not to be held. A numerical example exhibiting an oscillatory behavior illustrates the main results. © 2014 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd. Source

Sassatelli L.,French National Center for Scientific Research | Declercq D.,ENSEA Cergy
IEEE Transactions on Information Theory

In this paper, a new class of low-density parity-check (LDPC) codes, named hybrid LDPC codes, is introduced. Hybrid LDPC codes are characterized by an irregular connectivity profile and heterogeneous orders of the symbols in the codeword. It is shown in particular that the class of hybrid LDPC codes can be asymptotically characterized and optimized using density evolution (DE) framework, and a technique to maximize the minimum distance of the code is presented. Numerical assessment of hybrid LDPC code performances is provided, by comparing them to protograph-based and multiedge-type (MET) LDPC codes. Hybrid LDPC codes are shown to allow to achieve an interesting tradeoff between good error-floor performance and good waterfall region with nonbinary coding techniques. © 2010 IEEE. Source

Paolini E.,University of Bologna | Fossorier M.P.C.,ENSEA Cergy | Chiani M.,University of Bologna
IEEE Transactions on Information Theory

In this paper, a method for the asymptotic analysis of generalized low-density parity-check (GLDPC) codes and doubly generalized low-density parity-check (D-GLDPC) codes over the binary erasure channel (BEC), based on extrinsic information transfer (EXIT) chart, is described. This method overcomes the problem consisting of the impossibility to evaluate the EXIT function for the check or variable component codes, in situations where the information functions or split information functions for component codes are unknown. According to the proposed technique, GLDPC codes and D-GLDPC codes where the generalized check and variable component codes are random codes with minimum distance at least 2, are considered. A technique is then developed which finds the EXIT chart for the overall GLDPC or D-GLDPC code, by evaluating the expected EXIT function for each check and variable component code. This technique is finally combined with the differential evolution algorithm in order to generate some good GLDPC and D-GLDPC edge distributions. Numerical results of long, random codes, are presented which confirm the effectiveness of the proposed approach. They also reveal that D-GLDPC codes can outperform standard LDPC codes and GLDPC codes in terms of both waterfall performance and error floor. © 2006 IEEE. Source

Aggoune W.,ENSEA Cergy
Proceedings of the IEEE Conference on Decision and Control

In this paper, the problem of feedback stabilization of stochastic differential delay systems is considered. The systems under study are nonlinear, nonaffine and involve both discrete and distributed delays. By using a LaSalle-type theorem for stochastic systems, general conditions for stabilizing the closed-loop system with delays are obtained. In addition, stabilizing state feedback control laws are proposed. © 2011 IEEE. Source

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