265 research outputs found

    How to Complete Regulations in Multi-agent Systems

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    In this paper, we deal with regulations that may exist in multiagent systems in order to regulate agent behaviour. More precisely, we discuss two properties of regulations, consistency and ompleteness. After defining what consistency and completeness mean, we propose a way to consistently complete incomplete regulations. This contribution considers that regulations are expressed in a first order deontic logic. We will focus on particular regulations: information exchange policies

    A modal logic for reasoning on consistency and completeness of regulations

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    In this paper, we deal with regulations that may exist in multi-agent systems in order to regulate agent behaviour and we discuss two properties of regulations, that is consistency and completeness. After defining what consistency and completeness mean, we propose a way to consistently complete incomplete regulations. In this contribution, we extend previous works and we consider that regulations are expressed in a first order modal deontic logic

    Agents coopératifs et politiques d'échanges d'informations

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    National audienceDans les systĂšmes multiagents, les agents sont souvent supposĂ©s ĂȘtre coopĂ©ratifs les uns avec les autres dans leurs Ă©changes, ceci afin de mener Ă  bien une tĂąche globale. Ils sont Ă©galement souvent tenus de respecter la politique d'Ă©change d'informations du systĂšme qui rĂ©gule quels Ă©changes sont obligatoires, permis ou interdits entre les agents et sous quelles conditions. Comment dans ce cas les agents peuvent-ils ĂȘtre Ă  la fois coopĂ©ratifs et obĂ©issants ? Dans cet article, nous dĂ©finissons une politique d'Ă©change d'informations particuliĂšre, que nous appelons politique de coopĂ©ration, qui est la politique que les agents doivent respecter pour ĂȘtre coopĂ©ratifs. Ainsi, nous ramenons la problĂ©matique d'ĂȘtre Ă  la fois obĂ©issant et coopĂ©ratif Ă  la problĂ©matique de respecter deux politiques d'Ă©change d'informations diffĂ©rentes : la politique qui existe dĂ©jĂ  au sein du systĂšme et la politique de coopĂ©ration. Nous Ă©tudions Ă©galement le cas oĂč ces politiques sont conflictuelles et proposons alors de nouvelles dĂ©finitions des caractĂšres obĂ©issants et coopĂ©ratifs des agents

    A reasoning platform based on the MI Shapley inconsistency value

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    International audienceIn this paper we show how to build a reasoning platform us- ing an inconsistency value. The idea is to use an inconsistency value for evaluating how much each formula of the belief base is responsible of the inconsistency of the base. Then this evaluation allows us to obtain a strati cation (total pre-order) of the base, that can be used as the preferential input for di erent reasoning tasks, such as inference, belief revision, or conciliation. We show that the obtained operators are interesting and have good logical properties. We use as inconsistency value, the MI Shapley inconsistency value, that is known to have good properties, and that can be computed from minimal inconsistent subsets. We developed a java-based platform, that use the Sat4j library for computing the minimal inconsistent subsets, and that allows to have an e ective way to compute the MI Shapley inconsistent subsets. We implemented also several inference, revision and conciliation methods, that use this inconsistency value. So this provides a complete reasoning platform, that can be used for instance for academic purposes

    Can clicker use support learning in a dual-focused second language German course?

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    This study investigated clicker-use impact in a legal German lecture, given to 65 French students of Law in which the learning focus was both language and content. 36 participants who attended the entire course were tested. Upon their introductory session, students took a preliminary two-fold multiple-choice questionnaire involving 16 questions on legal terminology and 16 on course content. Throughout the 10- week semester, the lecturer administered all questions during regular courses. Each weekly session was conducted alternately with or without clickers. Students answered half of the questions about language and content using clickers, whereas the remaining half involved standard conditions with volunteers raising their hands to answer. At the end of their term, students took the same initial questionnaire as a post-test. A quantitative analysis was performed to assess (a) the enhancement of the acquisition of legal terminology and course content through clicker use and (b) the impact of learners’ pre-test scores on learning gains regarding terminology and content with or without clickers. The clicker group outperformed the non-clicker group with regard to a post-test concerning legal terminology. The findings demonstrate that clicker use alleviates the cognitive load induced by learning both new terminology and content

    Une logique modale pour raisonner sur la cohérence et la complétude de réglementations

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    Nous nous intéressons dans ce papier aux réglementations qui peuvent exister dans des systÚmes multi-agents pour réguler les comportements des agents. Plus précisément, nous travaillons sur deux propriétés des réglementations, la cohérence et la complétude. AprÚs avoir donné une définition de ces deux notions, nous proposons un cadre permettant de compléter de façon cohérente une réglementation incomplÚte. Nous considérons dans l'article que les réglementations sont exprimées dans une logique déontique du premier ordre

    Cohérence et complétude des réglementations en présence de contraintes

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    Cet article a pour objet l'étude des réglementations qui existent dans les systÚmes multi-agents et qui visent à réguler le comportement des agents. Plus précisément, nous nous intéressons à deux propriétés des réglementations : la cohérence et la complétude, et ce en présence de contraintes (lois de la nature, faits persistants) dont nous montrons l'influence. Nous montrons également comment compléter une réglementation incomplÚte tout en préservant sa cohérence. Ce travail considÚre que les réglementations sont exprimées en logique déontique du premier ordre

    Une conception pour une production efficace, une approche basée modÚles

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    International audienceThe concept of simultaneous engineering has been used for several years in the industry. However, it rarely aims to think the design of the product and the design of its industrial system (the factory) together. In this paper, we address the need to have a global view of architectural design and manufacturing throughout the entire design process. More precisely, we define a model-based approach which makes it possible to evaluate the impact of a product design on its manufacturability. This approach constitutes a first step, in a long-term perspective, to consider several high-level industrial systems and product designs together and choose the one that gives the best performances.Le concept d'ingénierie simultanée est utilisé depuis plusieurs années dans l'industrie. Cependant, il vise rarement à penser ensemble la conception du produit et la conception de son systÚme industriel (l'usine). Dans cet article, nous abordons la nécessité d'avoir une vision globale de la conception architecturale et de la fabrication tout au long du processus de conception. Plus précisément, nous définissons une approche basée sur un modÚle qui permet d'évaluer l'impact de la conception d'un produit sur sa faisabilité. Cette approche constitue une premiÚre étape, dans une perspective à long terme, pour considérer ensemble plusieurs systÚmes industriels de haut niveau et plusieurs conceptions de produits afin de choisir celui qui donne les meilleures performances

    Ordonnancement hiérarchique pour des missions multi-robots

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    International audienceWe are interested in real case studies involving tasks (here observations on areas of a field) that can be performed by disjunctive resources (robots), as well as operations to prepare these resources (robot movements between observations) which must themselves be decomposed into low-level operations (movements of each robot between different crossing points in the field where each link traversed cannot be occupied by more than one robot at a time). The robots transmit the observation data in real time to the mission centre using a transmission frequency (disjunctive resource). Each observation must be performed by several robots (redundancy) and precedence constraints may be imposed. The problem we consider is to allocate each observation to a robot, to schedule the observations for each one, and to plan the moving tasks in order to minimize the total duration of the mission. The goal is not to obtain an optimal solution, but to obtain good quality solutions quickly. We define a framework for the representation of hierarchical scheduling problems, where tasks are characterized by resource consumption and for which Constraint Programming Models (CMP) can be generated automatically. This framework is based on hierarchical task networks (HTNs), in which high-level tasks, defined by their preconditions and their effects on the state of the system, must be decomposed into primitive tasks by decomposition methods. The framework we consider can be easily generalized to cumulative resources with limited capacity or to non-renewable resources.Nous nous intĂ©ressons Ă  des Ă©tudes de cas rĂ©elles comportant des tĂąches (ici des observations sur des zones d’un terrain) qui peuvent ĂȘtre rĂ©alisĂ©es par des ressources disjonctives (robots), ainsi que des opĂ©rations de prĂ©paration de ces ressources (mouvements du robot entre observations) qui doivent elles-mĂȘmes ĂȘtre dĂ©composĂ©es en opĂ©rations de bas niveau (mouvements de chaque robot entre diffĂ©rents points de passage sur le terrain oĂč chaque lien parcouru ne peut pas ĂȘtre occupĂ© par plus d’un robot Ă  la fois). Les robots transmettent les donnĂ©es d’observation en temps rĂ©el au centre de mission en utilisant une frĂ©quence d’émission (ressource disjonctive). Chaque observation doit ĂȘtre rĂ©alisĂ©e par plusieurs robots (redondance) et des contraintes de prĂ©cĂ©dence peuvent ĂȘtre imposĂ©es. Le problĂšme que nous considĂ©rons consiste Ă  allouer chaque observation Ă  un robot, Ă  ordonnancer les observations pour chacun, et Ă  planifier les tĂąches de dĂ©placement de maniĂšre a minimiser la durĂ©e totale de la mission. L’objectif n’est pas l’obtention d’une solution optimale, mais de solutions de bonne qualitĂ© rapidement. Nous dĂ©finissons un cadre de reprĂ©sentation de problĂšmes d’ordonnancement hiĂ©rarchique, oĂč les tĂąches sont caractĂ©risĂ©es par des consommations de ressources et pour lequel des modĂšles de programmation par contraintes (PPC) peuvent ĂȘtre gĂ©nĂ©rĂ©s automatiquement. Ce cadre s’inspire des rĂ©seaux hiĂ©rarchiques de tĂąches (HTN), dans lesquels des tĂąches de haut niveau, dĂ©finies par leurs prĂ©-conditions et leurs effets sur l’état du systĂšme, doivent ĂȘtre dĂ©composĂ©es en tĂąches primitives par des mĂ©thodes de dĂ©composition. Le cadre que nous considĂ©rons peut ĂȘtre facilement gĂ©nĂ©ralisĂ© aux ressources cumulatives ayant une capacitĂ© limitĂ©e ou aux ressources non renouvelables

    Enterotoxigenic and Enterohemorrhagic <i>Escherichia coli</i>: Survival and Modulation of Virulence in the Human Gastrointestinal Tract

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    Enterotoxigenic Escherichia coli (ETEC) and Enterohemorrhagic Escherichia coli (EHEC) are major food‐ and water‐borne pathogens that constitute a serious public health threat in low‐income and developed countries, respectively. Survival and expression of virulence genes in the human digestive tract are key features in bacterial pathogenesis, but the mechanisms behind these processes remain largely unknown due to obvious prohibition of human studies. Use of well‐controlled and multi‐parametric in vitro models can aid in addressing knowledge gaps in ETEC and EHEC pathogenesis. After a general description of the physiopathology of ETEC and EHEC infections, this chapter will give an overview of all the in vitro studies that have investigated the effect of the main physicochemical and biotic parameters of the human gut on pathogen survival and expression of virulence factors. We bring a picture of how ETEC and EHEC are able to adapt to each of the successive environments of the human gastrointestinal tract by reading many cues provided by both the host and the gut microbiota
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