All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Page 1

Displaying 1 – 19 of 19

Showing per page

Rational semimodules over the max-plus semiring and geometric approach to discrete event systems

Stéphane Gaubert, Ricardo Katz (2004)

Kybernetika

We introduce rational semimodules over semirings whose addition is idempotent, like the max-plus semiring, in order to extend the geometric approach of linear control to discrete event systems. We say that a subsemimodule of the free semimodule 𝒮 n over a semiring 𝒮 is rational if it has a generating family that is a rational subset of 𝒮 n , 𝒮 n being thought of as a monoid under the entrywise product. We show that for various semirings of max-plus type whose elements are integers, rational semimodules...

Reachability and observability of linear systems over max-plus

Michael J. Gazarik, Edward W. Kamen (1999)

Kybernetika

This paper discusses the properties of reachability and observability for linear systems over the max-plus algebra. Working in the event-domain, the concept of asticity is used to develop conditions for weak reachability and weak observability. In the reachability problem, residuation is used to determine if a state is reachable and to generate the required control sequence to reach it. In the observability problem, residuation is used to estimate the state. Finally, as in the continuous-variable...

Regional boundary observability: a numerical approach

El Hassane Zerrik, Hamid Bourray, Ali Boutoulout (2002)

International Journal of Applied Mathematics and Computer Science

In this paper we review the concept of regional boundary observability, developed in (Michelitti, 1976), by means of sensor structures. This leads to the so-called boundary strategic sensors. A characterization of such sensors which guarantees regional boundary observability is given. The results obtained are applied to a two-dimensional system, and various cases of sensors are considered. We also describe an approach which leads to the estimation of the initial boundary state, which is illustrated...

Regional detection and reconstruction of unknown internal or boundary sources

Larbi Afifi, Abdelhaq El Jai, Malika Merry (2001)

International Journal of Applied Mathematics and Computer Science

The purpose of this paper is to study the problem of regional detection, to characterize internal or boundary regionally detectable sources and regionally spy sensors, and to establish a relationship between these sensors and regionally strategic sensors. It is shown how to reconstruct a regionally detectable internal or a boundary source from a given output, with an extension to the case when the output is affected by an observation error. Numerical results are given in the case of a diffusion...

Regional observation and sensors

Abdelhaq El Jai, Houria Hamzaoui (2009)

International Journal of Applied Mathematics and Computer Science

The purpose of this short paper is to provide original results related to the choice of the number of sensors and their supports for general distributed parameter systems. We introduce the notion of extended sensors and we show that the observation error decreases when the support of a sensor is widened. We also show that the observation error decreases when the number of sensors increases.

Remark on stabilization of tree-shaped networks of strings

Kaïs Ammari, Mohamed Jellouli (2007)

Applications of Mathematics

We consider a tree-shaped network of vibrating elastic strings, with feedback acting on the root of the tree. Using the d’Alembert representation formula, we show that the input-output map is bounded, i.e. this system is a well-posed system in the sense of G. Weiss (Trans. Am. Math. Soc. 342 (1994), 827–854). As a consequence we prove that the strings networks are not exponentially stable in the energy space. Moreover, we give explicit polynomial decay estimates valid for regular initial data.

Remarques sur l’observabilité pour l’équation de Laplace

Kim-Dang Phung (2003)

ESAIM: Control, Optimisation and Calculus of Variations

Nous quantifions la propriété de continuation unique pour le laplacien dans un domaine borné quand la condition aux bords est a priori inconnue. Nous établissons une estimation de dépen-dance de type logarithmique suivant la terminologie de John [5]. Les outils utilisés reposent sur les inégalités de Carleman et les techniques des travaux de Robbiano [8, 11]. Aussi, nous déterminons en application de l’inégalité d’observabilité obtenue un coût du contrôle approché pour un problème elliptique modèle....

Remarques sur l'observabilité pour l'équation de Laplace

Kim-Dang Phung (2010)

ESAIM: Control, Optimisation and Calculus of Variations

We consider the Laplace equation in a smooth bounded domain. We prove logarithmic estimates, in the sense of John [5] of solutions on a part of the boundary or of the domain without known boundary conditions. These results are established by employing Carleman estimates and techniques that we borrow from the works of Robbiano [8,11]. Also, we establish an estimate on the cost of an approximate control for an elliptic model equation.

Resolvent estimates in controllability theory and applications to the discrete wave equation

Sylvain Ervedoza (2009)

Journées Équations aux dérivées partielles

We briefly present the difficulties arising when dealing with the controllability of the discrete wave equation, which are, roughly speaking, created by high-frequency spurious waves which do not travel. It is by now well-understood that such spurious waves can be dealt with by applying some convenient filtering technique. However, the scale of frequency in which we can guarantee that none of these non-traveling waves appears is still unknown in general. Though, using Hautus tests, which read the...

Robust fault detection of singular LPV systems with multiple time-varying delays

Amir Hossein Hassanabadi, Masoud Shafiee, Vicenç Puig (2016)

International Journal of Applied Mathematics and Computer Science

In this paper, the robust fault detection problem for LPV singular delayed systems in the presence of disturbances and actuator faults is considered. For both disturbance decoupling and actuator fault detection, an unknown input observer (UIO) is proposed. The aim is to compute a residual signal which has minimum sensitivity to disturbances while having maximum sensitivity to faults. Robustness to unknown inputs is formulated in the sense of the H∞ -norm by means of the bounded real lemma (BRL)...

Robust Feedback Control Design for a Nonlinear Wastewater Treatment Model

M. Serhani, N. Raissi, P. Cartigny (2009)

Mathematical Modelling of Natural Phenomena

In this work we deal with the design of the robust feedback control of wastewater treatment system, namely the activated sludge process. This problem is formulated by a nonlinear ordinary differential system. On one hand, we develop a robust analysis when the specific growth function of the bacterium μ is not well known. On the other hand, when also the substrate concentration in the feed stream sin is unknown, we provide an observer of system and propose a design of robust feedback control in...

Robust nonlinear observer design for actuator fault detection in diesel engines

Boulaid Boulkroune, Issam Djemili, Abdel Aitouche, Vincent Cocquempot (2013)

International Journal of Applied Mathematics and Computer Science

This paper is concerned with actuator fault detection in nonlinear systems in the presence of disturbances. A nonlinear unknown input observer is designed and the output estimation error is used as a residual for fault detection. To deal with the problem of high Lipschitz constants, a modified mean-value theorem is used to express the nonlinear error dynamics as a convex combination of known matrices with time-varying coefficients. Moreover, the disturbance attenuation is performed using a modified...

Robust observer design for Sugeno systems with incremental quadratic nonlinearity in the consequent

Hoda Moodi, Mohammad Farrokhi (2013)

International Journal of Applied Mathematics and Computer Science

This paper is concerned with observer design for nonlinear systems that are modeled by T-S fuzzy systems containing parametric and nonparametric uncertainties. Unlike most Sugeno models, the proposed method contains nonlinear functions in the consequent part of the fuzzy IF-THEN rules. This will allow modeling a wider class of systems with smaller modeling errors. The consequent part of each rule contains a linear part plus a nonlinear term, which has an incremental quadratic constraint. This constraint...

Robust observer design for time-delay systems: a Riccati equation approach

Anas Fattouh, Olivier Sename, Jean-Michel Dion (1999)

Kybernetika

In this paper, a method for H ∞ observer design for linear systems with multiple delays in state and output variables is proposed. The designing method involves attenuating of the disturbance to a pre-specified level. The observer design requires solving certain algebraic Riccati equation. An example is given in order to illustrate the proposed method.

Robust sensor fault estimation for descriptor-LPV systems with unmeasurable gain scheduling functions: application to an anaerobic bioreactor

Francisco-Ronay López-Estrada, Jean-Christophe Ponsart, Didier Theilliol, Carlos-Manuel Astorga-Zaragoza, Jorge-Luis Camas-Anzueto (2015)

International Journal of Applied Mathematics and Computer Science

This paper addresses the design of a state estimation and sensor fault detection, isolation and fault estimation observer for descriptor-linear parameter varying (D-LPV) systems. In contrast to where the scheduling functions depend on some measurable time varying state, the proposed method considers the scheduling function depending on an unmeasurable state vector. In order to isolate, detect and estimate sensor faults, an augmented system is constructed by considering faults to be auxiliary state...

Currently displaying 1 – 19 of 19

Page 1