151 research outputs found

    Multi-Agent Environment for Modelling and Solving Dynamic Transport Problems

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    The transport requirements in modern society are becoming more and more important. Thus, offered transport services need to be more and more advanced and better designed to meet users demands. Important cost factors of many goods are transport costs. Therefore, a reduction of costs, a better adjustment of strategies to the demand as well as a better planning and scheduling of available resources are important for the transport companies. This paper is aimed at modelling and simulation of transport systems, involving a dynamic Pickup and Delivery problem with Time Windows and capacity constraints (PDPTW). PDPTW is defined by a set of transport requests which should be performed while minimising costs expressed by the number of vehicles, total distance and total travel time. Each request is described by two locations: pickup and delivery, periods of time when the operations of pickup or delivery can be performed and a load to be transported. The nature of this problem, its distribution and the possibility of using a lot of autonomous planning modules, lead us to use a multi-agent approach. Our approach allows the modeling of entities which do not appear in the classical PDPTW such as company organisation, communication among vehicles, interactions between vehicles and company dispatcher or different strategies of requests acceptation by different vehicles. This paper presents also a software environment and experimentations to validate the proposed approach

    Un système multi-agents pour la gestion des connaissances hétérogènes et distribuées

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    La gestion des connaissances permet d'identifier et de capitaliser les savoirs faires de l'entreprise afin de les organiser et de les diffuser. Cette thèse propose un système de gestion des connaissances hétérogènes et distribuées, appelé OCEAN. Basé sur les ontologies et sur un système multi-agents, OCEAN a pour but de résoudre le problème de la capitalisation et de réutilisation des connaissances provenant de plusieurs sources différentes, afin d aider les acteurs métiers dans le processus de développement de produits mécaniques. Le système OCEAN repose sur un cycle de vie de quatre étapes Ce cycle de vie possède les phases : d identification, d extraction, de validation et se termine par la réutilisation des connaissances. Chaque phase constitue l objectif d une organisation d agents.L identification dans le système OCEAN consiste à définir les connaissances par un expert métier sous la forme d une ontologie. Les ontologies sont utilisées dans notre système pour représenter les connaissances définis d une façon structurée et formelle afin d être compréhensible par les machines. L extraction des connaissances dans OCEAN est réalisée par les agents de manière automatique à l aide des ontologies créées par les experts métiers. Les agents interagissent avec les différentes applications métiers via des services web. Le résultat de cette phase est stocké dans une mémoire organisationnelle. La validation des connaissances consiste à permettre aux acteurs métiers de valider les connaissances de la mémoire organisationnelle dans un wiki sémantique. Ce wiki permet de présenter les connaissances de la mémoire organisationnelle aux acteurs pour les réutiliser, les évaluer et les faire évoluer. La réutilisation des connaissances dans OCEAN est inspiré de travaux antérieurs intégrés au sein d OCEAN. Les quatre phases du cycle de vie des connaissances traitées dans cette thèse nous ont permis de réaliser un système apte à gérer les connaissances hétérogènes et distribuées dans une entreprise étendue.Among the goals of Knowledge Management we can cite the identification and capitalization of the know-how of companies in order to organize and disseminate them. This thesis proposes a heterogeneous and distributed knowledge management system, called OCEAN. Based on ontologies and multi-agents system, OCEAN aims to solve the problem of capitalization and reuse of multi-sources knowledge in order to assist business actors in the development process of mechanical products. The OCEAN system is based on a knowledge life cycle composed by four steps. This knowledge life cycle begins with the identification then extraction, validation and finishes with knowledge reuse. Each step is the goal of an organization of agents.The identification in OCEAN system consists in the definition of knowledge by a business expert with an ontology. Ontologies are used in our system to represent the knowledge, defined by the business expert, in a structured and formal way in order to be understandable by machines. Agents according to the ontology defined by business experts realize knowledge extraction in OCEAN automatically. Agents interact with professional softwares via web services. The result of this extraction is stored in an organizational memory (OM). Validation of knowledge in OCEAN relies on business actors that validate the knowledge of the OM in a semantic wiki. This wiki allows also the presentation of this knowledge to business actors in order to reuse, evaluate or evolve it. Previous works, integrated within OCEAN, inspires the knowledge reuse step. The four steps lifecycle discussed in this thesis has enabled us to achieve a system that can manage heterogeneous and distributed knowledge in an extended enterprise.BELFORT-UTBM-SEVENANS (900942101) / SudocSudocFranceF

    Software-hardware Integration and Human-centered Benchmarking for Socially-compliant Robot Navigation

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    The social compatibility (SC) is one of the most important parameters for service robots. It characterises the interaction quality between a robot and a human. In this paper, we first introduce an open-source software-hardware integration scheme for socially-compliant robot navigation and then propose a human-centered benchmarking framework. For the former, we integrate one 3D lidar, one 2D lidar, and four RGB-D cameras for robot exterior perception. The software system is entirely based on the Robot Operating System (ROS) with high modularity and fully deployed to the embedded hardware-based edge while running at a rate that exceeds the release frequency of sensor data. For the latter, we propose a new human-centered performance evaluation metric that can be used to measure SC quickly and efficiently. The values of this metric correlate with the results of the Godspeed questionnaire, which is believed to be a golden standard approach for SC measurements. Together with other commonly used metrics, we benchmark two open-source socially-compliant robot navigation methods, in an end-to-end manner. We clarify all aspects of the benchmarking to ensure the reproducibility of the experiments. We also show that the proposed new metric can provide further justification for the selection of numerical metrics (objective) from a human perspective (subjective).Comment: 8 pages, 8 figure

    Responsible conduct of research-creation: a portrait of an uncharted field of research

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    Responsible conduct of research (RCR) is ubiquitous, and present in most areas of research. One area that has received little attention is Research-Creation (RC): • an emergent eld at the interface of academic research and creative activities • in Quebec, Canada, RC is de ned as “research activities or approaches that foster the creation or interpretation/ performance of literary or artistic works of all types” Researcher-Creators – who are at the same time researchers and practising artists, musicians, or designers – may be faced with very di erent issues or challenges from colleagues in the rest of academia. • How are RCR issues are articulated in RC? • How does the heterogeneous RC community responds to institutional policies or provincial/national RCR guidelines? This review aimed to identify and categorize RCR issues, and RC-speci c factors.FRQ Action concerté

    Organismal defenses versus environmentally mediated protection from herbivores: Unraveling the puzzling case of Desmarestia viridis (Phaeophyta)

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    Abstract The role of anti-herbivore organismal defenses in algae-herbivore interaction is frequently investigated without taking into account the potential role of environmental factors in mediating the interaction. Here we reexamine the interaction between the highly acidic, brown alga Desmarestia viridis and the green sea urchin, Strongylocentrotus droebachiensis, by incorporating a previously overlooked facet, the effect of changes in the wave environment on the ability of the urchin to establish contact with the alga. Factorial experiments in a wave tank (presence versus absence of waves; real versus mimic algae) showed that the aggregation of urchins on D. viridis was more than 2-fold greater in the absence than in the presence of waves. Similar numbers of urchins made contact with natural and mimic D. viridis plants, both with and without waves, indicating that any external release of chemicals (acid) from the alga had no perceptible repulsive effect on the urchin. The ability of the urchins to climb onto D. viridis increased markedly when urchin density attained a critical level. These results were consistent with field observations that urchins readily attack D. viridis under conditions of low wave action but do not under conditions of moderate wave action. We conclude (1) that the chemical makeup of D. viridis alone is neither necessary nor sufficient to limit contacts by the urchins and that (2) wave action is a major factor explaining the survival of D. viridis on urchin barrens, because waves limit the movements of the urchins towards the alga. We recommend that studies addressing marine algal defenses against herbivores be more comprehensive and examine interactions between algal traits, the physical environment, and the abundance and behavioral repertoire of herbivores

    Responsible Conduct of Research in Research-Creation: Moving into Uncharted Terrain

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    Responsible conduct of research (RCR) is ubiquitous, and present in most areas of research. One area that has received little attention is Research-Creation (RC): • an emergent eld at the interface of academic research and creative activities • in Quebec, Canada, RC is de ned as “research activities or approaches that foster the creation or interpretation/ performance of literary or artistic works of all types” Researcher-Creators – who are at the same time researchers and practising artists, musicians, or designers – may be faced with very di erent issues or challenges from colleagues in the rest of academia. • How do researcher-creators reconcile their dual obligations to creation and to research? • Are the usual research ethics guidelines (e.g., TCPS2, ICH relevant and how do they apply? • How do the creative/artistic dimensions of research a ect evaluations by grant committees and REBs? To better understand how RCR issues are articulated in the very heterogeneous RC community, we combine here results from a literature review and an international survey on RCR in RC.FRQ Action concerté
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