Volume 4, 2006

1. Numerical study of some iterative solvers for acoustics in unbounded domains

Nabil Gmati ; Naouel Zrelli.
The aim of this paper is to study some iterative methods, based on the domain decomposition approach to solve the acoustic harmonic wave propagation in an unbounded domain. We describe how our methodology applies to semi-infinite closed guides and to acoustic scattering problems. In both cases, we use some well-known transparent boundary conditions by imposing on a fictitious boundary a boundary condition by the means of a Fourier expansion. For numerical purposes, we propose an original algorithm based on a fixed-point technique applied to the problem set in the truncated domain. We will interprate this method as a domain decomposition solver which allows to state convergence results. The improvement brought by this method is a consequence of the sparsity presentation of the finite matrix system which is decomposed only once.

2. SenPeer : un système pair-à-pair de médiation de données

David C. Faye ; Gilles Nachouki ; Patrick Valduriez.
In this article we present SenPeer, a new Peer-to-Peer data management system allowing data sharing among experts working on the development of the Senegal river in a decentralized and lexible fashion. SenPeer has a Super-Peer network topology based on an organization of peers in semantic domains and in which peers can contribute XML documents, relational or object databases. Each peer exports its data in a common formalism which has a graph structure semantically enriched with a set of keywords in order to guide mappings discovery. Mappings discovery relies on a set of fuzzy similarity measures. Moreover they allow the establishement of a semantic topology that is independent of the underlying network topology which is the basis for intelligent query routing.

3. Exécution d'un graphe cubique de tâches sur un réseau bi-dimensionnel et asymptotiquement optimal

Clémentin Tayou Djamegni.
This work proposes a scheduling strategy, based on re-indexing transformations, for task graphs associated with a linear timing function. This scheduling strategy is used to execute a cubical task graph, for which all the tasks have the sane execution time and inter-tasks communication delays are neglected, on a two-dimensional array of processors which is asymptotically space-optimal with respect to the timing function.

4. Suite d’ensembles partiellement ordonnés

Bachir Sadi.
This work is to study an order D(P) on maximal antichains of a given order. D(P) is an order included in the order which defines the Lattice of maximal antichains AM(P), introduced by R.P. Dilworth, in 1960. In [3], T.Y. Kong and P. Ribenboim have proved that there exists an integer i such that Di(P) is a chain, where Di(P)=D(D(…D(P))), i times. We find the smallest i, noted cdev(P) such that Di(P) is a chain for some particular classes of orders and we approximate this parameter in the general case of order.

5. On the representation of L-M algebra by intuitionistic fuzzy subsets

Zedam Lemnaouar ; Amroune Abdelaziz.
In this paper we introduce the notions of intuitionistic weak alpha-cut and untuitionistic strong alpha-cut of intuitionistic fuzzy subsets of a universe X. These notions lead us to show that the set IF(X) of all intuitionistic fuzzy subsets on a universe X can be equipped with a structure of involutive theta-valued Lukasiewicz-Moisil algebra. Conversely, we show that every involutive theta-valued Lukasiewicz-Moisil algebra can be embedded into an algebra of intuitionistic fuzzy subsets.

6. Mise en oeuvre de tests unitaires dans un contexte de programmation eXtrème répartie

Ibrahim Lokpo ; Michel Babri ; Gérard Padiou.
eXtreme Programming (XP) is a methodology based on principles and practices for quickly developing software. However this approach requires the programmers to be co-located. Many research projects investigate how to extend XP to a distributed environment. However the challenge is to carry out the XP approach without conflicting with the distributed constraints. Our work takes place in this way. More precisely, we propose an extension based on assistance for supporting distributed unit testing, one of the key principles of XP methodology.

7. A dynamical model of plant growth with full retroaction between organogenesis and photosynthesis

Amélie Rostand-Mathieu ; Paul-Henry Cournède ; Philippe Reffye.
In this paper are presented new mathematical developments in plant growth modelling and simulation. GreenLab Model is a functional-structural plant growth model, it combines both organogenesis (architecture) and photosynthesis (biomass production and repartition). New improvements concern the retroaction of photosynthesis on organogenesis. We present in this paper the influence of available biomass on the number of metamers in a growth unit and on the branching. The general theory is introduced and applied to simple trees. Some interesting behaviours are underlined.