Volume 12, 2010


1. Nouveau critère de séparation aveugle de sources cyclostationnaires au second ordre

Ould Mohamed, Mohamed Salem ; Keziou, Amor ; Fenniri, Hassan ; Delaunay, Georges.
Le travail présenté ici vise à proposer un modèle pour la composition des services web sémantiques. Ce modèle est basé sur une représentation sémantique de l'ensemble des concepts manipulés par les services web d’un domaine d'application, à savoir, les opérations et les concepts statiques utilisés pour décrire les propriétés des services web. Différents niveaux d'abstraction sont donnés au concept opération pour permettre un accès progressif aux services concrets. Ainsi, deux plans de composition à granularités différentes (abstrait et concrets) sont générés. Ceci permettrade réutiliser des plans déjà construits pour répondre à des besoins similaires et même avec despréférences modifiées.

2. A hybrid Ant Colony Algorithm for the exam timetabling problem

Abounacer, R. ; Boukachour, J. ; Dkhissi, B. ; El Hilali Alaoui, A..
Due to increased student numbers and regulation changes educational institutions that allow for greater flexibility, operations researchers and computer scientists have renewed their interest in developing effective methods to resolve the examination timetabling problem. Thus, in the intervening decades, important progress was made in the examination timetabling problem with appearance of adaptation of meta-heuristics. This paper presents a hybridization of the Ant Colony Algorithm and a Complete Local search with Memory heuristic, in order to maximize as much as possible; the free time between consecutive exams for each student, while respecting the conflict constraints, a student cannot sit more than one exam in the same timeslot.

3. Distributed Load Balancing Model for Grid Computing

Yagoubi, Belabbas ; Meddeber, Meriem.
Most of the existing load balancing strategies were interested in distributed systems which were supposed to have homogeneous resources interconnected with homogeneous and fast networks. For Grid computing, these assumptions are not realistic because of heterogeneity, scalability and dynamicity characteristics. For these environments the load balancing problem is then a new challenge presently for which many research projects are under way. In this perspective, our contributions through this paper are two folds. First, we propose a distributed load balancing model which can represent any Grid topology into a forest structure. After that, we develop on this model, a load balancing strategy at two levels; its principal objectives : the reduction of average response time of tasks and their transferring cost. The proposed strategy is naturally distributed with a local decision, which allows the possibility of avoiding use of wide area communication network.