A Video Transmission Framework Using Components and Multi-Agent Systems

International audienceThis paper presents an application of video transmission over Internet, which goal is to be used in a cooperative plat- form. This application uses proxies during the transmission to adapt the video (changing the size, the framerate and/or the encoding format). Adaptation is a necessity in this kind of application, due to the diversity of receivers (computers, mobile phones, PDA . . . ). During the design process, we chose to use component ori- ented programming and multi-agent systems. We present here how these two paradigms help us to have a flexible and evolutive application, and, for each transmission?s step, what is the most appropriated solution. At the end, we also present tests that have been made to evaluate the power needed by the proxies in order to discuss about benefits that can be brought by our architecture

Mise en place et évaluation d'un algorithme de répartition de charge pour les plateformes de simulations distribuées basées sur les systèmes multi-agents

International audienceCet article traite de la problématique de la répartition de charge dans les systèmes multi-agents à travers un algorithme qui assure la distribution de ces agents. Le besoin est né de l'observation de fréquents problèmes de surcharge lors de simulations basées sur ces systèmes multi-agents. Miro, qui est une plateforme de simulation à grande échelle de la mobilité urbaine en est un exemple concret. La difficulté de ces travaux se situe dans la considération des spécificités des plateformes de simulation orientée agent : autonomie des entités à distribuer et forte imprévisibilité du système. Nous adaptons un algorithme de répartition de charge appelé Comet aux spécificités des simulations distribuées à base d'agents. Cet algorithme est basé sur l'emploi d'un indicateur appelé " crédit " qui pour chaque agent quantifie son affinité pour chaque machine et détermine les meilleurs agents candidats à la migration. Hormis l'algorithme en lui même, ce document en présente une implémentation et une évaluation sur un simulateur développé avec Netlogo. Le but final est d'identifier les paramètres à prendre en considération pour assurer le bon fonctionnement de l'algorithme lors de son implémentation sur une plateforme réelle de simulation

Automating {UML} Models Merge for Web Services Testing

International audienceThis paper presents a method for merging UML models which takes place in a quality evaluation framework for Web Services (WS). This framework, called iTac-QoS, is an ex- tended UDDI server (a yellow pages system dedicated to WS), using model based testing to assess quality. WS ven- dors have to create UML model of their product and our framework extracts tests from it. Depending on the results of the test execution, a mark is given to WS. This mark per- mits to customers to have an idea about the quality of WS they find on our UDDI server. Up today, our framework was limited to WS which did not use other WS. This was justified by the fact that it is im- possible for vendors to create a good model of a foreign product. Our method for model merging solves this prob- lem: each vendor produces models of its own product, and we automatically merge the different models. The resulting model from this merging represents the composition of the different WS. For each type of diagram present in the models (class, instance or state-chart diagram), a method is proposed in order to produce a unique model. In addition to this, a solu- tion is proposed to merge all OCL code in the class modeling the WS under test. Unfortunately, this process introduces inconsistencies in the resulting model, that falsify the results of the subsequent test generation phase. We thus propose to detect such inconsistencies in order to distinguish incon- sistent and unreachable test targets

Étude comparative des plateformes parallèles pour systèmes multi-agents

International audienceLa simulation est devenue un outil indispensable à la recherche pour explorer les systèmes sans avoir recours à l'expérience. En fonction des caractéristiques du système la méthode de modélisation utilisée pour représenter le système varie. Les systèmes multi-agents sont ainsi souvent utilisés pour modéliser et simuler les systèmes complexes. Quel que soit le type de modélisation utilisée, l'augmentation de la taille et de la précision du modèle fait croître le nombre des calculs, rendant nécessaire l'utilisation de systèmes parallèles. Dans cet article, nous nous intéressons aux plateformes de simulation multi-agent parallèles. Notre contribution est une étude comparative de ces différentes plateformes, dans un contexte de calcul intensif. Nous présentons une analyse qualitative, à partir de critères que nous avons définis, puis un comparatif de performance, sur la base d'un modèle agent que nous avons implémenté sur chaque plateforme

Multiplicity of complex hypersurface singularities, Rouche' satellites and Zariski's problem

Soient $f,g\colon (\hbox{\aa C}^n,0) \to (\hbox{\aa C},0)$ des germes de fonctions holomorphes r\'eduits. Nous montrons que $f$ et $g$ ont la m\^eme multiplicit\'e en 0 si et seulement s'il existe des germes r\'eduits $f'$ et $g'$ analytiquement \'equivalents \`a $f$ et $g$, respectivement, tels que $f'$ et $g'$ satisfassent une in\'egalit\'e du type de Rouch\'e par rapport \`a un `petit' cercle g\'en\'erique autour de~0. Comme application, nous donnons une reformulation de la question de Zariski sur la multiplicit\'e et une r\'eponse partielle positive \`a celle--ci.Comment: Final versio

An Agent-Based Framework for Urban Mobility Simulation

International audienceMobility study is composed of many research areas which one interests us: urban mobility. In the literature, urban mobilities are represented by analytical techniques like stochastic laws or they are defined by simulation tools like Multi-Agents Systems (MAS). The goal of our work is to define citizen behaviour in order to observe population dynamics by a simulation. This strategy is facilitated by a meta-model and a toolkit which are used with a particular method. The latter begins by a conceptual representation of each mobile and finishes by a mobility simulator. This paper aims at describing the mobility simulation toolkit. Thanks to this framework, mobility simulator development is sim- plified. It allows us to create distributed applications which are based on MAS

A component based system for S-maintenance.

International audienceThanks to ICT, Web emergency and Internet, the achievement of maintenance services and monitoring can be performed automatically, remotely and through various distributed information systems. Hence the emergence of the concept of services offered through maintenance architectures, ranging from autonomic systems to integrated systems where knowledge management, cooperation and collaboration are vital to any operation. Into this context, new services like intelligent maintenance, self maintenance, etc are required. To this end, a new concept called s-maintenance is emerged. This concept defines a new generation of maintenance systems founded on a knowledge based system. While existing systems don't respond to the characteristics of this new generation of systems, we design in this paper an architecture of a maintenance component based system respecting the characteristics of s-maintenance. Each component in the system is defined to respond to one or many characteristics of this concept

First IJCAI International Workshop on Graph Structures for Knowledge Representation and Reasoning (GKR@IJCAI'09)

International audienceThe development of effective techniques for knowledge representation and reasoning (KRR) is a crucial aspect of successful intelligent systems. Different representation paradigms, as well as their use in dedicated reasoning systems, have been extensively studied in the past. Nevertheless, new challenges, problems, and issues have emerged in the context of knowledge representation in Artificial Intelligence (AI), involving the logical manipulation of increasingly large information sets (see for example Semantic Web, BioInformatics and so on). Improvements in storage capacity and performance of computing infrastructure have also affected the nature of KRR systems, shifting their focus towards representational power and execution performance. Therefore, KRR research is faced with a challenge of developing knowledge representation structures optimized for large scale reasoning. This new generation of KRR systems includes graph-based knowledge representation formalisms such as Bayesian Networks (BNs), Semantic Networks (SNs), Conceptual Graphs (CGs), Formal Concept Analysis (FCA), CPnets, GAI-nets, all of which have been successfully used in a number of applications. The goal of this workshop is to bring together the researchers involved in the development and application of graph-based knowledge representation formalisms and reasoning techniques

Automated UML models merging for web services testing

International audienceThis paper presents a method for merging UML models which takes place in a quality evaluation framework for Web Services (WS). This framework, called iTac-QoS, is an extended UDDI server (a yellow pages system dedicated to WS), using model based testing to assess quality. WS vendors have to create UML model of their product and our framework extracts tests from it. Depending on the results of the test execution, a mark is given to WS. This mark gives to the cus- tomers an idea about the quality of WS they find on our UDDI server. Up today, our framework was limited to WS which did not use other WS. This was justified by the fact that it is impossible for vendors to cre- ate a good model of a foreign product. Our method for model merging solves this problem: each vendor produces models of its own product, and we automatically merge the different models. The resulting model from this merging represents the composition of the different WS. For each type of diagram present in the models (class, instance or state- chart diagram), a method is proposed in order to produce a unique model. In addition to this, a solution is proposed to merge all OCL code in the class modeling the WS under test. Unfortunately, this pro- cess introduces inconsistencies in the resulting model, that falsify the results of the subsequent test generation phase. We thus propose to detect such inconsistencies in order to distinguish inconsistent and un- reachable test targets