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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Vers un système de réutilisation ds connaissances en ingénierie de conception / Towards a system for the reuse of design engineering knowledge

Ben Miled, Achraf 15 July 2011 (has links)
Pour arriver à gérer les changements fréquents des exigences des clients, des produits de plus en plus complexes et faire face à une concurrence de plus en plus dure, les organisations cherchent sans cesse à améliorer l’utilisation de leur portefeuille de connaissances.On remarque ainsi, que depuis une quinzaine d’années, bon nombre d’entre elles ont commencé à structurer leur démarche de gestion des connaissances. Ces démarches ont pour but de résoudre un ou plusieurs des problèmes suivants : le départ en retraite de cadres qui détiennent une connaissance critique, le partage de bonnes pratiques développées par une unité de production, la stimulation de l’innovation d’un centre de recherche, etc. Dans la réalité, la mise en place effective de ces initiatives soulève de nombreux problèmes liés tantôt à la nature tacite de la connaissance, à l’existence de barrières culturelles qu’à l’adoption d’un système logiciel de gestion des connaissances. Cette thèse se situe dans le cadre général de la gestion des connaissances lors du processus de conception de produits. Nous nous intéressons en particulier aux problématiques de la capitalisation et de la réutilisation des connaissances dans le processus de conception collaborative et routinière à l'aide d'un système logiciel de gestion des connaissances. L’objectif principal de cette thèse est de proposer un Système de Gestion des Connaissances (SGC) pour la capitalisation et la réutilisation des connaissances, fondé sur une approche organisationnelle et le paradigme des Systèmes Multi-Agents (SMA). Le choix des SMA est naturel car il permet la modélisation et l'implémentation des SGC comme des systèmes distribués où des acteurs différents (les acteurs métiers), agissent de manière autonome pour atteindre un but précis et interagissent afin de réaliser un but commun. Nous proposons une modélisation de système de gestion des connaissances (SGC) qui s'appuie sur la méthodologie ASPECS dédiée à l'analyse, la conception et le déploiement de systèmes complexes. Cette démarche d'analyse et de conception permet de mettre en évidence les objectifs d'un SGC et les principaux mécanismes de son fonctionnement. Parmi les activités d'ASPECS, l'identification des besoins se fait par une approche orientée buts qui permet la modélisation des objectifs du SGC ainsi que les acteurs impliqués et leurs dépendances.La contribution de cette thèse est composée de deux parties. La première consiste en l'analyse du domaine de la gestion des connaissances en ayant à l'esprit l'objectif de développer un SGC basé sur une approche organisationnelle qui met l’accent sur les aspects sociaux et coopératifs du processus de conception et qui gère la réutilisation des connaissances. La deuxième partie vise à la conception d'un SMA sous la forme d’un collecticiel mettant en œuvre notre approche de réutilisation des connaissances au fil de l’eau. / In order to manage the frequent changes in customer requirements, products increasingly complex and face an extreme hard and tougher competition; organizations are always seeking to improve the use of their knowledge portfolio. Thus, it is noted that since fifteen years, many of them have begin to structure their approach to knowledge management. These steps are designed to solve one or more of the following: the retirement of executives who have critical knowledge, sharing the best practices developed by a unit of production, the stimulation of innovation research center etc. In reality, the actual implementation of these initiatives raises many issues now with the tacit nature of knowledge, the existence of cultural barriers to the adoption of a software system for knowledge management. This thesis is in the general framework of knowledge management in the process of product design. We are particularly interested in issues of capitalization and reuse of knowledge in the collaborative design process and routinely using a software system for knowledge management. The main objective of this thesis is to provide a Knowledge Management System (KMS) for capitalization and reuse of knowledge, based on an organizational approach and the paradigm of Multi-Agent Systems (MAS). The choice of MAS is natural because it allows the modeling and implementation of KMS as distributed systems where different actors (business actors) act independently to achieve a specific purpose and interact to achieve a common goal. We propose a model of knowledge management system (KMS) based on the methodology ASPEC dedicated to the analysis, design and deployment of complex systems. This approach allows analysis and design to highlight the objectives of a KMS and the major mechanisms of its functioning. The activities of ASPEC, the identification of needs are a goal-oriented approach that allows modeling of the targets of KMS and the actors involved and their dependencies. The contribution of this thesis is composed of two parts. The first is the analysis of the field of knowledge management, bearing in mind the objective to develop a KMS based on an organizational approach that focuses on social and collaborative design process and manages reuse of knowledge. The second part is to design a MAS as a groupware implementing our approach to reuse of knowledge.
342

Coévolution d'organisations sociales et spatiales dans les systèmes multi-agents : application aux systèmes de tagging collaboratifs / Coevolution of social and spatial organizations in multi-agent systems : application to collaborative tagging systems

Rupert, Maya 02 September 2009 (has links)
L’évolution du Web et de ses applications subit depuis quelques années une mutation vers les technologies qui incluent la dimension sociale comme entité de première classe. Nous témoignons dans le passage du Web 1.0 au Web 2.0 puis au Web 3.0, 4.0 etc.. que les utilisateurs et les réseaux sociaux qui se forment sont au centre de cette évolution. Le web exhibe aussi toutes les caractéristiques d’un système complexe. Ces propriétés systèmes complexes et cette dimension sociale doivent être prises en considération lors de la conception et le développement des applications web. Considérons le cas des systèmes de tagging ou d’étiquetage collaboratifs. Ces systèmes sont un exemple de systèmes complexes, auto-organisés et socialement conscients. Le paradigme des systèmes multi-agents coordonné par les mécanismes d’auto-organisations a été utilisé d’une façon effective pour la conception et modélisation des systèmes complexes. Les systèmes de tagging collaboratifs actuels ne prennent pas l’avantage complet de leurs caractéristiques systèmes complexes, surtout dans l’adaptation à leur environnement et l’émergence de nouvelles fonctionnalités. Dans ce travail de thèse, nous proposons un modèle pour la conception et développement d’un nouveau système d’étiquetage collaboratif MySURF (My Similar Users, Resources, Folksonomies), utilisant une approche multi-agents gouvernée par la coévolution des organisations sociales et spatiales des agents. Nous montrons comment ce système proposé offre plusieurs nouvelles fonctionnalités qui peuvent améliorer les systèmes d’étiquetage collaboratifs actuels. / The evolution of the Web and its applications has undergone in the last few years a mutation towards technologies that include the social dimension as a first class entity. We are witnessing in the evolution of the web from the web 1.0 to web 2.0 to web 3.0 and eventually web 4.0 that the users, their interactions and the emerging social networks are in the center of this evolution. The web also exhibits all the characteristics of a complex system. These complex systems properties and this social dimension must be taken into consideration in the design and the development of new web applications. Let us consider the case of collaborative tagging systems. These systems are an example of complex, self-organized and socially aware systems. The multi-agent systems paradigm coordinated by self-organizations mechanisms was used in an effective way for the design and modeling of the complex systems. Current collaborative tagging systems do not take full advantage of the characteristics of complex systems, especially in adapting to their environment and the emergence of new features. In this thesis, we propose a model for the design and development of a new collaborative tagging system MySURF (My Similar Users, Resources, Folksonomies), using a multi-agent system approach governed by the coevolution of the social and spatial organization of the agents. We show how the proposed system offers several new features that can improve current collaborative tagging systems.
343

Graphs and networks for the analysis of autonomous agent systems

Hendrickx, Julien 14 February 2008 (has links)
<p>Autonomous agent systems are systems in which many simple entities, called “agents”, interact with each other. The behaviour resulting from such interactions can be much more complex than that of the individual agents. A group of interacting agents can for example accomplish tasks that no single agent could.</p> <p>Nature provides several examples of autonomous agent systems, such as flocks of birds and insects, schools of fish, and anthills. Progresses in robotics, electronics and telecommunications make it now also possible to design such systems in order to accomplish particular tasks, such as the surveillance or exploration of areas, or the maintenance of some environments.</p> <p>In this thesis, we analyze two issues related to autonomous agent systems, and more precisely, to the influence of the inter-agent communication network on the system behaviour. In a first part, we consider the problem of preserving the shape of a multi-agent formation by explicitly maintaining the distances between some agents constant. We study the case of distance constraints that are unilateral, that is, constraints for which the responsibility is given to a one of the two agents concerned. This leads to the notions of persistence and constraint consistence. The second part is devoted to the consensus problems: agents have a value which they update by averaging that of other agents. Eventually, all agents may obtain a common value, in which case we say that the system reaches a consensus. One major difficulty in the study of such system is the possible dependence of the interaction and communication topology on the values of the agents. We study two paradigmatic systems in which this dependence can be taken into account, and obtain results on their convergence and on the stability of their equlibria.</p>
344

Design, Production And Development Of Mini/micro Robots To Form A Cooperative Colony

Basaran, Dilek 01 September 2003 (has links) (PDF)
Design, production and development of individual mini/micro robots and then formation of their cooperative colony are the main topics of this thesis. The produced mini/micro robots are as small and light as possible. In addition, they are multifunctional (programmable), flexible and intelligent while maintaining a very low production cost. Mini/micro robots, called MinT-DB series are able to communicate with each other to work cooperatively. Moreover, these robots can be the basis for the future studies considering the application of artificial intelligence and modeling of live colonies in the nature. Traditional design, production and assembly techniques have been used widely up to now. However, none of them were related with the mini/micro scale. Therefore, this thesis can help people in understanding the difficulties of the design, production, and assembly of the mini/micro systems under the light of the reported science. In this thesis, instead of examining a specific application field of mini/micro robotic systems, a technology demonstrative work is carried out. Therefore, this thesis contributes to the mini/micro robotic technology, which is also very new and popular in today&amp / #8217 / s world, with the robots having the dimensions of 7.5x6x6 cm.
345

Control Of A Mobile Robot Swarm Via Informed Robots

Celikkanat, Hande 01 September 2008 (has links) (PDF)
In this thesis, we study how and to what extent a self-organized mobile robot flock can be guided by informing some of the robots within the flock about a preferred direction of motion. Specifically, we extend a flocking behavior that was shown to maneuver a swarm of mobile robots as a cohesive group in free space, avoiding obstacles. In its original form, this behavior does not have a preferred direction and the flock would wander aimlessly. In this study, we incorporate a preference for a goal direction in some of the robots. These informed robots do not signal that they are informed (a.k.a. unacknowledged leadership) and instead guide the swarm by their tendency to move in the desired direction. Through experimental results with physical and simulated robots we show that the self-organized flocking of a robot swarm can be effectively guided by an informed minority of the flock. We evaluate the system using a number of quantitative metrics: First, we propose to use the mutual information metric from Information Theory as a dynamical measure of the information exchange. Then, we discuss the accuracy metric from directional statistics and size of the largest cluster as the measures of system performance. Using these metrics, we perform analyses from two points of views: In the transient analyses, we demonstrate the information exchange between the robots as the time advances, and the increase in the accuracy of the flock when the conditions are suitable for an adequate amount of information exchange. In the steady state analyses, we investigate the interdependent effects of the size of the flock in terms of the robots in it, the ratio of informed robots in the flock over the total flock size, the weight of the direction preference behavior, and the noise in the system.
346

Design And Implementation Of A P2p Contracting Overlay

Celebi, Remzi 01 September 2009 (has links) (PDF)
Today, with widespread use of Internet in many areas, the common procedures frequently encountered in business life such as contracting and negotiation need to be automated. The distributed structure of the Internet and the difficulty of resources dispersed on one center makes such a system to have a distributed architecture . In this study, for first time, automatization of a contracting form through business processes was proposed and was carried out. A peer to peer process contracting overlay what we call Peer-Con is developed. The system is an extension of Java Agent Development Framework (JADE) and uses IEEE Foundation for Intelligent Physical Agents (FIPA) Agent Communication Language (ACL) standard. Cost aware flexible representation of process capabilities / description of an operator to decide on whether given capabilities turnout to an agreement or not and self organization of peer connectivity for better contracting performance are distinguishing features of the system. The system can easily be adapted to different domains while the core functionality remains the same. Practical use of Peer-Con is shown by two applications from different domains / Driving Route Calculation on Web Maps and Digital Signal Processing Module (DSPM) product planning domain.
347

Co-located collaboration in interactive spaces for preliminary design

Jones, Alistair 05 December 2013 (has links) (PDF)
The preliminary design phase occurs near the launch of an engineering project, normally after an initial requirements gathering phase. Through a series of meetingswhich gathers the key actors of a project, effective preliminary design involves discussion and decision-making punctuated by group creativity techniques. These activities are designed to explore the potential solutions of the problem, such asbrainstorming or causal analysis, or to address the project itself, such as collaborative project planning. Such activities are usually conducted in traditional meeting rooms with pen and paper media, which requires significant time and effort to prepare, perform, and later render into a digitally exploitable format. These processes have resisted previous attempts of computer-supported solutions, because any additional instruments risk obstructing the natural collaboration and workflow that make these activities so beneficial. Over the past decade, technologies such as interactive table tops, interactive wall displays, speech recognition software, 3D motion sensing cameras, and handheld tablets and smartphones have experienced significant advances in maturity. Theirform factors resemble the physical configuration of traditional pen-and-paper environments,while their "natural" input devices (based on multi-touch, gestures, voice, tangibles, etc.) allow them to leverage a user's pre-existing verbal, spatial,social, motor and cognitive skills. Researchers hypothesize that having these devices working in concert inside interactive spaces could augment collaboration forco-located (i.e. physically present) groups of users.There currently exist several interactive spaces in the literature, illustrating awide range of potential hardware configurations and interaction techniques. The goal of this thesis is first to explore what qualities these interactive spaces should exhibit in their interaction design, particularly with regard to preliminary designactivities, and second, to investigate how their heterogeneous and distributed computing devices can be unified into a flexible and extensible distributed computing architecture. The first main contribution of this thesis is an extensive presentation of an interactive space, which at its core uses a configuration not yet fully explored inprevious literature : a large multitouch table top and a large multitouch interactive Abstract board display. The design of this interactive space is driven by observations o fgroups engaged in preliminary design activities in traditional environments and a literature review aimed at extracting user-centered design guide lines. Special consideration is given to the user interface as it extends across multiple shared displays, and maintains a separation of concerns regarding personal and group work. Finally, evaluations using groups of five and six users show that using such an interactive space, coupled with our proposed multi-display interaction techniques, leads to a more effective construction of the digital artifacts used in preliminary design.The second main contribution of this thesis is a multi-agent infrastructure forthe distributed computing environment which effectively accommodates a widerange of platforms and devices in concerted interaction. By using agent-oriented programming and by establishing a common content language for messaging, the infrastructure is especially tolerant of network faults and suitable for rapid prototyping of heterogeneous devices in the interactive space.
348

Investigating the effects of cooperative vehicles on highway traffic flow homogenization: analytical and simulation studies

Monteil, Julien 29 January 2014 (has links) (PDF)
The traffic engineering community currently faces the advent of a new generation of Intelligent Transportation Systems (ITS), known as cooperative systems. More specifically, the recent developments of connected and autonomous vehicles, i.e. cooperative vehicles, are expected to cause a societal shift, changing the way people commute on a daily basis and relate to transport in general. The research presented in this dissertation is motivated by the need for proper understanding of the possible inputs of cooperative vehicles in a traffic stream. Beyond legal aspects regarding the introduction of such vehicles and considerations on standardization and harmonization of the communication norms, the research focuses on the use of communication for highway traffic flow homogenization. In particular, the selected approach for the introduction of cooperation inherits from the theory of traffic flow and the recent developments of microscopic traffic models. Cooperation can first be introduced as a form of multi-anticipation, which can either come from drivers' behaviors or from communication. A mathematical framework for investigating the impact of perturbations into a steady-state traffic is proposed for the class of time continuous car-following models. Linear stability analyses are refined for forward and backward multi-anticipation, exploring the underlying importance of considering upstream information. The linear stability analyses for all wavelengths can be deepened by the mean of the graphical root locus analysis, which enables comparisons and design of strategies of cooperation. The positive influence of bilateral cooperation and of added linear control terms are highlighted. Weakly non-linear analyses are also performed, and the equations of solitary waves appearing at the frontier of the instability domain are obtained. A simple condition over the partial derivatives of the dynamical system is found to determine the acceleration regime of the leading edge of the travelling wave. Following these analytical results, one aim is to simulate a realistic traffic thereby reproducing the driving behavior variability. A Next Generation Simulation trajectory dataset is used to calibrate three continuous car-following models. A methodology involving data filtering, robust calibration, parameters estimation and sampling of realistic parameters is detailed, and allows realistic traffic with stop-and-go waves appearances to be replicated. Based on these simulated trajectories, previous analytical results are confirmed, and the growing perturbations are removed for various coverage rates of cooperative vehicles and adequately tuned cooperative strategies. Finally the issue of information reliability is assessed for a mixed fleet of cooperative and non-cooperative vehicles. The modeling choice consists in building a three layers multi-agent framework that enables the following properties to be defined: the physical behavior of vehicles, the communication possibilities, and the trust each vehicle -or agent- has in another vehicle information or in itself. The investigation of trust and communication rules allow the model to deal with high rates of disturbed cooperative vehicles sensors and to learn in real time the quality of the sent and received information. It is demonstrated that appropriate communication and trust rules sensibly increase the robustness of the network to perturbations coming from exchanges of unreliable information.
349

Control of Self-Organizing and Geometric Formations

Pruner, Elisha 24 January 2014 (has links)
Multi-vehicle systems offer many advantages in engineering applications such as increased efficiency and robustness. However, the disadvantage of multi-vehicle systems is that they require a high level of organization and coordination in order to successfully complete a task. Formation control is a field of engineering that addresses this issue, and provides coordination schemes to successfully implement multi-vehicle systems. Two approaches to group coordination were proposed in this work: geometric and self-organizing formations. A geometric reconfiguring formation was developed using the leader-follower method, and the self-organizing formation was developed using the velocity potential equations from fluid flow theory. Both formation controllers were first tested in simulation in MATLAB, and then implemented on the X80 mobile robot units. Various experiments were conducted to test the formations under difficult obstacle scenarios. The robots successfully navigated through the obstacles as a coordinated as a team using the self-organizing and geometric formation control approaches.
350

An integrated evolutionary system for solving optimization problems

Barkat Ullah, Abu Saleh Shah Muhammad, Engineering & Information Technology, Australian Defence Force Academy, UNSW January 2009 (has links)
Many real-world decision processes require solving optimization problems which may involve different types of constraints such as inequality and equality constraints. The hurdles in solving these Constrained Optimization Problems (COPs) arise from the challenge of searching a huge variable space in order to locate feasible points with acceptable solution quality. Over the last decades Evolutionary Algorithms (EAs) have brought a tremendous advancement in the area of computer science and optimization with their ability to solve various problems. However, EAs have inherent difficulty in dealing with constraints when solving COPs. This thesis presents a new Agent-based Memetic Algorithm (AMA) for solving COPs, where the agents have the ability to independently select a suitable Life Span Learning Process (LSLP) from a set of LSLPs. Each agent represents a candidate solution of the optimization problem and tries to improve its solution through cooperation with other agents. Evolutionary operators consist of only crossover and one of the self-adaptively selected LSLPs. The performance of the proposed algorithm is tested on benchmark problems, and the experimental results show convincing performance. The quality of individuals in the initial population influences the performance of evolutionary algorithms, especially when the feasible region of the constrained optimization problems is very tiny in comparison to the entire search space. This thesis proposes a method that improves the quality of randomly generated initial solutions by sacrificing very little in diversity of the population. The proposed Search Space Reduction Technique (SSRT) is tested using five different existing EAs, including AMA, by solving a number of state-of-the-art test problems and a real world case problem. The experimental results show SSRT improves the solution quality, and speeds up the performance of the algorithms. The handling of equality constraints has long been a difficult issue for evolutionary optimization methods, although several methods are available in the literature for handling functional constraints. In any optimization problems with equality constraints, to satisfy the condition of feasibility and optimality the solution points must lie on each and every equality constraint. This reduces the size of the feasible space and makes it difficult for EAs to locate feasible and optimal solutions. A new Equality Constraint Handling Technique (ECHT) is presented in this thesis, to enhance the performance of AMA in solving constrained optimization problems with equality constraints. The basic concept is to reach a point on the equality constraint from its current position by the selected individual solution and then explore on the constraint landscape. The technique is used as an agent learning process in AMA. The experimental results confirm the improved performance of the proposed algorithm. This thesis also proposes a Modified Genetic Algorithm (MGA) for solving COPs with equality constraints. After achieving inspiring performance in AMA when dealing with equality constraints, the new technique is used in the design of MGA. The experimental results show that the proposed algorithm overcomes the limitations of GA in solving COPs with equality constraints, and provides good quality solutions.

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