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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.
201

Un schéma d'emprunt de ressources pour l'adaptation du comportement d'applications distribuées / A resource borrowing schema for behavior adaptation of distributed applications

Batouma, Narkoy 30 September 2011 (has links)
Les systèmes d’exploitation utilisent très généralement une politique de « meilleur effort » (Best-effort) pour exécuter les applications. Tant que les ressources sont suffisantes, les applications s’exécutent normalement mais quand les ressources deviennent insuffisantes, des mécanismes de contrôle sont nécessaires pour continuer à obtenir des services de qualité acceptable. Cette thèse a pour objectif de gérer la QoS des applications distribuées. La première partie propose un middleware totalement décentralisé pour contrôler l’utilisation des ressources des applications distribuées. Cette approche se fonde sur une planification approximative et un schéma d’emprunt de ressources afin d’améliorer la QoS globale du système. Via ce schéma d’emprunt, chaque nœud construit localement une vue détaillée de la disponibilité des ressources dans le système. La présence da la connaissance de la disponibilité des ressources en local permet à chaque nœud de prendre localement des décisions et de planifier les tâches des applications. Pour un contrôle plus fin de l’exécution, la deuxième partie ajoute un support pour l’adaptation du comportement des applications. Le middleware utilise un modèle général des applications sous forme de graphe d’exécution décoré avec les besoins en ressources. Un chemin dans le graphe est une exécution possible de l’application avec une certaine utilité, et ce sont ces chemins qui fournissent les degrés de liberté dont le middleware a besoin pour adapter la consommation des ressources au contexte. Les applications coopèrent avec le middleware dans le processus de gestion de la QoS lors de l’admission puis durant toute l’exécution. Le middleware est le chef d’orchestre et c’est lui qui pilote et c’est lui qui pilote l’exécution des actions des applications (arcs dans le graphe) Pour valider notre approche, un prototype à base d’agents a été réalisé. Les résultats démontrent l’intérêt de notre approche. / Generally, Operating Systems control and execute applications based on a best effort policy. As long as resources are sufficient, applications are normally executed but when resources become scarce, control mechanisms (graceful degradation) are necessary to maintain acceptable QoS. This thesis aims to manage the QoS of distributed applications. The first part of the thesis proposes a fully decentralized middleware to control the use of resources of distributed applications. This approach is based on a resource borrowing schema and an approximate scheduling in order to improve the overall QoS provided by the system. Using this borrowing schema, each node locally constructs a comprehensive view of resources availability in the system. The local knowledge of resources availability makes it possible for each node to make decisions and to schedule the execution of the applications. To finely control execution, the second part of the thesis adds a support for behavior adaptation of applications. The middleware interprets a general model of applications as an execution graph enriched with resources requirements. Each application must be designed according to this model to be manageable by the middleware (intrusive approach). A path in the graph is a possible execution of application with a certain utility. These paths provide degrees of freedom needed by the middleware to adapt resource consumption to the context. During the QoS management process, applications cooperate with the middleware at admission and execution phase. The middleware guides and controls the execution of applications actions (edges in the execution graph). To validate our approach, a prototype based on agents has been implemented using JADE. The results show the interest of our approach.
202

Evolução de estratégias e controle inteligente em sistemas multi-robóticos robustos

Pessin, Gustavo 22 February 2008 (has links)
Made available in DSpace on 2015-03-05T13:59:42Z (GMT). No. of bitstreams: 0 Previous issue date: 22 / Nenhuma / Este trabalho está relacionado com a aplicação de técnicas de Inteligência Artificial no desenvolvimento de um Sistema Multi-Agente robótico aplicado ao problema da monitoração e combate a incêndios em áreas florestais. O objetivo macro é evoluir estratrégias de formação de equipes de combate a incêndio (unidade de controle) e criar métodos robustos de navegação em agentes robóticos (unidades de combate), considerando um ambiente virtual de simulação realística.No sistema proposto, uma equipe de agentes autônomos trabalha cooperativamente a fim de realizar com sucesso a identificação e o combate a incêndios em áreas florestais, sem intervenção humana. O ambiente virtual 3D suporta uma série de características fundamentais para a simulação realística da operação, como terrenos irregulares, processos naturais e restrições físicas na criação e uso de robôs móveis. Este ambiente foi implementado através do uso das bibliotecas OSG, ODE e Demeter. A operacão multi-agente depende essencialmente de duas etapas: p / This work is related to the application of Artificial Intelligence techniques to develop a Multi-Agent Robotic System applied to the problem of monitoring wild forest fires and to the execution of fire fighting actions. Our main goal was to evolve strategies (control unit) in order to define the positioning of the fire-fighting autonomous robotic team and to create robust navigation methods used to control robotic agents (combat units). This work was developed based on simulations accomplished using a realistic 3D virtual environment, specially implemented for this purpose, using the software libraries OSG, Demeter and ODE. In the proposed system, a team of autonomous agents work cooperatively in order to successfully perform the identification and fighting of forest fires, without any human intervention. The 3D virtual environment includes several features for realistic simulation of this task, as for example, adoption of irregular terrains, natural processes simulation (e.g. fire propagation), and simulati
203

Conception et Optimisation Distribuée d’un Système d’Information des Services d’Aide à la Mobilité Urbaine Basé sur une Ontologie Flexible dans le Domaine de Transport / Design and Optimization of Distributed Information Systems of Services to Aid Urban Mobility Based on a Flexible Ontology in the Transport Domain

Saad, Sawsan 10 December 2010 (has links)
De nos jours, les informations liées au déplacement et à la mobilité dans un réseau de transport représentent sans aucun doute un potentiel important.Ces travaux visent à mettre en œuvre un Système d’Information de Service d’Aide à la Mobilité Urbaine (SISAMU).Le SISAMU doit pouvoir procéder par des processus de décomposition des requêtes simultanées en un ensemble de tâches indépendantes. Chaque tâche correspond à un service qui peut être proposé par plusieurs fournisseurs d’information en concurrence, avec différents coûts, temps de réponse et formats. Le SISAMU est lié à un Réseau informatique Etendu et distribué de Transport Multimodal (RETM) qui comporte plusieurs sources d’information hétérogènes des différents services proposés aux utilisateurs de transport. L’aspect dynamique, distribué et ouvert du problème, nous a conduits à adopter une modélisation multi-agent pour assurer au système une évolution continue et une flexibilité pragmatique. Pour ce faire, nous avons proposé d’automatiser la modélisation des services en utilisant la notion d’ontologie. Notre SISAMU prend en considération les éventuelles perturbations sur le RETM.Ansi, nous avons créé un protocole de négociation entre les agents. Le protocole de négociation proposé qui utilise l’ontologie de la cartographie se base sur un système de gestion des connaissances pour soutenir l'hétérogénéité sémantique. Nous avons détaillé l’Algorithme de Reconstruction Dynamique des Chemins des Agents (ARDyCA) qui est basé sur l’approche de l’ontologie cartographique. Finalement, les résultats présentés dans cette thèse justifient l’utilisation de l’ontologie flexible et son rôle dans le processus de négociation / Nowadays, information related on displacement and mobility in a transport network represents certainly a significant potential. So, this work aims to modeling, to optimize and to implement an Information System of Services to Aid the Urban Mobility (ISSAUM).The ISSAUM has firstly to decompose each set of simultaneous requests into a set of sub-requests called tasks. Each task corresponds to a service which can be proposed different by several information providers with different. An information provider which aims to propose some services through our ISSAUM has to register its ontology. Indeed, ISSAUM is related to an Extended and distributed Transport Multimodal Network (ETMN) which contains several heterogeneous data sources. The dynamic and distributed aspects of the problem incite us to adopt a multi-agent approach to ensure a continual evolution and a pragmatic flexibility of the system. So, we proposed to automate the modeling of services by using ontology idea. Our ISSAUM takes into account possible disturbance through the ETMN. In order to satisfy user requests, we developed a negotiation protocol between our system agents. The proposed ontology mapping negotiation model based on the knowledge management system for supporting the semantic heterogeneity and it organized as follow: Negotiation Layer (NL), the Semantic Layer (SEL), and the Knowledge Management Systems Layer(KMSL).We detailed also the reassignment process by using Dynamic Reassigned Tasks (DRT) algorithm supporting by ontology mapping approach. Finally, the experimental results presented in this thesis, justify the using of the ontology solution in our system and its role in the negotiation process
204

Élaboration d'ontologies médicales pour une approche multi-agents d'aide à la décision clinique / A multi-agent framework for the development of medical ontologies in clinical decision making

Shen, Ying 20 March 2015 (has links)
La combinaison du traitement sémantique des connaissances (Semantic Processing of Knowledge) et de la modélisation des étapes de raisonnement (Modeling Steps of Reasoning), utilisés dans le domaine clinique, offrent des possibilités intéressantes, nécessaires aussi, pour l’élaboration des ontologies médicales, utiles à l'exercice de cette profession. Dans ce cadre, l'interrogation de banques de données médicales multiples, comme MEDLINE, PubMed… constitue un outil précieux mais insuffisant car elle ne permet pas d'acquérir des connaissances facilement utilisables lors d’une démarche clinique. En effet, l'abondance de citations inappropriées constitue du bruit et requiert un tri fastidieux, incompatible avec une pratique efficace de la médecine.Dans un processus itératif, l'objectif est de construire, de façon aussi automatisée possible, des bases de connaissances médicales réutilisables, fondées sur des ontologies et, dans cette thèse, nous développons une série d'outils d'acquisition de connaissances qui combinent des opérateurs d'analyse linguistique et de modélisation de la clinique, fondés sur une typologie des connaissances mises en œuvre, et sur une implémentation des différents modes de raisonnement employés. La connaissance ne se résume pas à des informations issues de bases de données ; elle s’organise grâce à des opérateurs cognitifs de raisonnement qui permettent de la rendre opérationnelle dans le contexte intéressant le praticien.Un système multi-agents d’aide à la décision clinique (SMAAD) permettra la coopération et l'intégration des différents modules entrant dans l'élaboration d'une ontologie médicale et les sources de données sont les banques médicales, comme MEDLINE, et des citations extraites par PubMed ; les concepts et le vocabulaire proviennent de l'Unified Medical Language System (UMLS).Concernant le champ des bases de connaissances produites, la recherche concerne l'ensemble de la démarche clinique : le diagnostic, le pronostic, le traitement, le suivi thérapeutique de différentes pathologies, dans un domaine médical donné.Différentes approches et travaux sont recensés, dans l’état de question, et divers paradigmes sont explorés : 1) l'Evidence Base Medicine (une médecine fondée sur des indices). Un indice peut se définir comme un signe lié à son mode de mise en œuvre ; 2) Le raisonnement à partir de cas (RàPC) se fonde sur l'analogie de situations cliniques déjà rencontrées ; 3) Différentes approches sémantiques permettent d'implémenter les ontologies.Sur l’ensemble, nous avons travaillé les aspects logiques liés aux opérateurs cognitifs de raisonnement utilisés et nous avons organisé la coopération et l'intégration des connaissances exploitées durant les différentes étapes du processus clinique (diagnostic, pronostic, traitement, suivi thérapeutique). Cette intégration s’appuie sur un SMAAD : système multi-agent d'aide à la décision. / The combination of semantic processing of knowledge and modelling steps of reasoning employed in the clinical field offers exciting and necessary opportunities to develop ontologies relevant to the practice of medicine. In this context, multiple medical databases such as MEDLINE, PubMed are valuable tools but not sufficient because they cannot acquire the usable knowledge easily in a clinical approach. Indeed, abundance of inappropriate quotations constitutes the noise and requires a tedious sort incompatible with the practice of medicine.In an iterative process, the objective is to build an approach as automated as possible, the reusable medical knowledge bases is founded on an ontology of the concerned fields. In this thesis, the author will develop a series of tools for knowledge acquisition combining the linguistic analysis operators and clinical modelling based on the implemented knowledge typology and an implementation of different forms of employed reasoning. Knowledge is not limited to the information from data, but also and especially on the cognitive operators of reasoning for making them operational in the context relevant to the practitioner.A multi-agent system enables the integration and cooperation of the various modules used in the development of a medical ontology.The data sources are from medical databases such as MEDLINE, the citations retrieved by PubMed, and the concepts and vocabulary from the Unified Medical Language System (UMLS).Regarding the scope of produced knowledge bases, the research concerns the entire clinical process: diagnosis, prognosis, treatment, and therapeutic monitoring of various diseases in a given medical field.It is essential to identify the different approaches and the works already done.Different paradigms will be explored: 1) Evidence Based Medicine. An index can be defined as a sign related to its mode of implementation; 2) Case-based reasoning, which based on the analogy of clinical situations already encountered; 3) The different semantic approaches which are used to implement ontologies.On the whole, we worked on logical aspects related to cognitive operators of used reasoning, and we organized the cooperation and integration of exploited knowledge during the various stages of the clinical process (diagnosis, prognosis, treatment, therapeutic monitoring). This integration is based on a SMAAD: multi-agent system for decision support.
205

Apport des Systèmes Multi-Agent et de la logique floue pour l'assistance au tuteur dans une communauté d'apprentissage en ligne / Contribution of Multi-Agent Systems and Fuzzy logic to support tutors in Learning Communities

Chaabi, Youness 11 July 2016 (has links)
La place importante du tutorat dans la réussite d'un dispositif de formation en ligne a ouvert un nouvel axe de recherche dans le domaine des EIAH (Environnements Informatiques pour l'Apprentissage Humain). Nos travaux se situent plus particulièrement dans le champ de recherches des ACAO. Dans un contexte collaboratif, le tutorat et les outils « d'awareness » constituent des solutions admises pour faire face à l'isolement qui très souvent, mène à l'abandon de l'apprenant. Ainsi, du fait des difficultés rencontrées par le tuteur pour assurer un encadrement et un suivi appropriés à partir des traces de communication (en quantités conséquentes) laissées par les apprenants, nous proposons une approche multi-agents pour analyser les conversations textuelles asynchrones entre apprenants. Ces interactions sont révélatrices de comportements sociaux-animateur, indépendant, etc... qu'il nous paraît important de pouvoir repérer lors d'une pédagogie de projet pour permettre aux apprenants de situer leurs travaux par rapport aux autres apprenants et situer leur groupe par rapport aux autres groupes d'une part, et d'autre part permettre au tuteur d'accompagner les apprenants dans leur processus d'apprentissage, repérer et soutenir les individus en difficulté pour leur éviter l'abandon. Ces indicateurs seront déduits à partir des grands volumes d'échanges textuels entre apprenants.L'approche a été ensuite testée sur une situation réelle, qui a montré une parfaite concordance entre les résultatsobservés par des tuteurs humains et ceux déterminés automatiquement par notre système. / The growing importance of online training has put emphasis on the role of remote tutoring. A whole new area of research, dedicated to environment for human learning (EHL), is emerging. We are concerned with this field. More specifically, we will focus on the monitoring of learners.The instrumentation and observation of learners activities by exploiting interaction traces in the EHL and the development of indicators can help tutors to monitor activities of learners and support them in their collaborative learning process. Indeed, in a learning situation, the teacher needs to observe the behavior of learners in order to build an idea about their involvement, preferences and learning styles so that he can adapt the proposed activities. As part of the automatic analysis of collaborative learner¿s activities, we describe a multi agent approach for supporting learning activities in a Virtual Learning Environment context. In order to assist teachers who monitor learning processes, viewed as a specific type of collaboration, the proposed system estimates a behavioral (sociological) profile for each student. This estimation is based on automatic analysis of students textual asynchronous conversations. The determined profiles are proposed to the teacher and may provide assistance toteacher during tutoring tasks. The system was experimented with students of the master "software quality" of the Ibn Tofail University. The results obtained show that the proposed approach is effective and gives satisfactory results.
206

Urban Growth Modeling Based on Land-use Changes and Road Network Expansion

Rui, Yikang January 2013 (has links)
A city is considered as a complex system. It consists of numerous interactivesub-systems and is affected by diverse factors including governmental landpolicies, population growth, transportation infrastructure, and market behavior.Land use and transportation systems are considered as the two most importantsubsystems determining urban form and structure in the long term. Meanwhile,urban growth is one of the most important topics in urban studies, and its maindriving forces are population growth and transportation development. Modelingand simulation are believed to be powerful tools to explore the mechanisms ofurban evolution and provide planning support in growth management. The overall objective of the thesis is to analyze and model urban growth basedon the simulation of land-use changes and the modeling of road networkexpansion. Since most previous urban growth models apply fixed transportnetworks, the evolution of road networks was particularly modeled. Besides,urban growth modeling is an interdisciplinary field, so this thesis made bigefforts to integrate knowledge and methods from other scientific and technicalareas to advance geographical information science, especially the aspects ofnetwork analysis and modeling. A multi-agent system was applied to model urban growth in Toronto whenpopulation growth is considered as being the main driving factor of urbangrowth. Agents were adopted to simulate different types of interactiveindividuals who promote urban expansion. The multi-agent model with spatiotemporalallocation criterions was shown effectiveness in simulation. Then, anurban growth model for long-term simulation was developed by integratingland-use development with procedural road network modeling. The dynamicidealized traffic flow estimated by the space syntax metric was not only used forselecting major roads, but also for calculating accessibility in land-usesimulation. The model was applied in the city centre of Stockholm andconfirmed the reciprocal influence between land use and street network duringthe long-term growth. To further study network growth modeling, a novel weighted network model,involving nonlinear growth and neighboring connections, was built from theperspective of promising complex networks. Both mathematical analysis andnumerical simulation were examined in the evolution process, and the effects ofneighboring connections were particular investigated to study the preferentialattachment mechanisms in the evolution. Since road network is a weightedplanar graph, the growth model for urban street networks was subsequentlymodeled. It succeeded in reproducing diverse patterns and each pattern wasexamined by a series of measures. The similarity between the properties of derived patterns and empirical studies implies that there is a universal growthmechanism in the evolution of urban morphology. To better understand the complicated relationship between land use and roadnetwork, centrality indices from different aspects were fully analyzed in a casestudy over Stockholm. The correlation coefficients between different land-usetypes and road network centralities suggest that various centrality indices,reflecting human activities in different ways, can capture land development andconsequently influence urban structure. The strength of this thesis lies in its interdisciplinary approaches to analyze andmodel urban growth. The integration of ‘bottom-up’ land-use simulation androad network growth model in urban growth simulation is the major contribution.The road network growth model in terms of complex network science is anothercontribution to advance spatial network modeling within the field of GIScience.The works in this thesis vary from a novel theoretical weighted network modelto the particular models of land use, urban street network and hybrid urbangrowth, and to the specific applications and statistical analysis in real cases.These models help to improve our understanding of urban growth phenomenaand urban morphological evolution through long-term simulations. Thesimulation results can further support urban planning and growth management.The study of hybrid models integrating methods and techniques frommultidisciplinary fields has attracted a lot attention and still needs constantefforts in near future. / <p>QC 20130514</p>
207

Sistema basado en tecnologías del conocimiento para entornos de servicios web semánticos

García Sánchez, Francisco 28 September 2007 (has links)
En esta tesis se ha desarrollado un marco de trabajo que hace uso de las tecnologías de agentes y de Servicios Web Semánticos para la elaboración de aplicaciones que puedan tratar con el dinamismo de la Web, al tiempo que se pueden beneficiar de características como la autonomía, el aprendizaje y el razonamiento. Éste es el punto en que cobra relevancia la Ingeniería Ontológica. Las ontologías son los componentes que permiten que la comunicación entre agentes y Servicios Web, situados a distintos niveles de abstracción, se produzca de forma fluida y sin interpretaciones erróneas. La arquitectura del marco de trabajo desarrollado consta, fundamentalmente, de un entorno multi-agente, un conjunto de bases de conocimiento y diversas interfaces que permiten al sistema comunicarse, de forma efectiva, con las entidades externas identificadas, a saber, Servicios Web y proveedores de servicios, entidades (usuarios) consumidores de servicios, y desarrolladores. / In this thesis, a knowledge-based Semantic Web Services framework that successfully integrates Intelligent Agents and Semantic Web Services technologies has been developed. For achieving this combination, the framework takes an ontology-centred approach. Ontologies are the facilitating technology that enables a seamlessly communication between agents and services.
208

Land Use Change and Economic Opportunity in Amazonia: An Agent-based Model

Cabrera, Arthur Raymond January 2009 (has links)
Economic changes such as rising açaí prices and the availability of off-farm employment are transforming the landscape of the Amazonian várzea, subject to decision-making at the farming household level. Land use change results from complex human-environment interactions which can be addressed by an agent-based model. An agent-based model is a simulation model composed of autonomous interacting entities known as agents, built from the bottom-up. Coupled with cellular automata, which forms the agents’ environment, agent-based models are becoming an important tool of land use science, complementing traditional methods of induction and deduction. The decision-making methods employed by agent-based models in recent years have included optimization, imitation, heuristics, classifier systems and genetic algorithms, among others, but multiple methods have rarely been comparatively analyzed. A modular agent-based model is designed to allow the researcher to substitute alternative decision-making methods. For a smallholder farming community in Marajó Island near Ponta de Pedras, Pará, Brazil, 21 households are simulated over a 40-year period. In three major scenarios of increasing complexity, these households first face an environment where goods sell at a constant price throughout the simulated period and there are no outside employment opportunities. This is followed by a scenario of variable prices based on empirical data. The third scenario combines variable prices with limited employment opportunities, creating multi-sited households as members emigrate. In each scenario, populations of optimizing agents and heuristic agents are analyzed in parallel. While optimizing agents allocate land cells to maximize revenue using linear programming, fast and frugal heuristic agents use decision trees to quickly pare down feasible solutions and probabilistically select between alternatives weighted by expected revenue. Using distributed computing, the model is run through several parameter sweeps and results are recorded to a cenral database. Land use trajectories and sensitivity analyses highlight the relative biases of each decision-making method and illustrate cases where alternative methods lead to significantly divergent outcomes. A hybrid approach is recommended, employing alternative decision-making methods in parallel to illustrate inefficiencies exogenous and endogenous to the decision-maker, or allowing agents to select among multiple methods to mitigate bias and best represent their real-world analogues.
209

Land Use Change and Economic Opportunity in Amazonia: An Agent-based Model

Cabrera, Arthur Raymond January 2009 (has links)
Economic changes such as rising açaí prices and the availability of off-farm employment are transforming the landscape of the Amazonian várzea, subject to decision-making at the farming household level. Land use change results from complex human-environment interactions which can be addressed by an agent-based model. An agent-based model is a simulation model composed of autonomous interacting entities known as agents, built from the bottom-up. Coupled with cellular automata, which forms the agents’ environment, agent-based models are becoming an important tool of land use science, complementing traditional methods of induction and deduction. The decision-making methods employed by agent-based models in recent years have included optimization, imitation, heuristics, classifier systems and genetic algorithms, among others, but multiple methods have rarely been comparatively analyzed. A modular agent-based model is designed to allow the researcher to substitute alternative decision-making methods. For a smallholder farming community in Marajó Island near Ponta de Pedras, Pará, Brazil, 21 households are simulated over a 40-year period. In three major scenarios of increasing complexity, these households first face an environment where goods sell at a constant price throughout the simulated period and there are no outside employment opportunities. This is followed by a scenario of variable prices based on empirical data. The third scenario combines variable prices with limited employment opportunities, creating multi-sited households as members emigrate. In each scenario, populations of optimizing agents and heuristic agents are analyzed in parallel. While optimizing agents allocate land cells to maximize revenue using linear programming, fast and frugal heuristic agents use decision trees to quickly pare down feasible solutions and probabilistically select between alternatives weighted by expected revenue. Using distributed computing, the model is run through several parameter sweeps and results are recorded to a cenral database. Land use trajectories and sensitivity analyses highlight the relative biases of each decision-making method and illustrate cases where alternative methods lead to significantly divergent outcomes. A hybrid approach is recommended, employing alternative decision-making methods in parallel to illustrate inefficiencies exogenous and endogenous to the decision-maker, or allowing agents to select among multiple methods to mitigate bias and best represent their real-world analogues.
210

Multi-Agent User-Centric Specialization and Collaboration for Information Retrieval

Mooman, Abdelniser January 2012 (has links)
The amount of information on the World Wide Web (WWW) is rapidly growing in pace and topic diversity. This has made it increasingly difficult, and often frustrating, for information seekers to retrieve the content they are looking for as information retrieval systems (e.g., search engines) are unable to decipher the relevance of the retrieved information as it pertains to the information they are searching for. This issue can be decomposed into two aspects: 1) variability of information relevance as it pertains to an information seeker. In other words, different information seekers may enter the same search text, or keywords, but expect completely different results. It is therefore, imperative that information retrieval systems possess an ability to incorporate a model of the information seeker in order to estimate the relevance and context of use of information before presenting results. Of course, in this context, by a model we mean the capture of trends in the information seeker's search behaviour. This is what many researchers refer to as the personalized search. 2) Information diversity. Information available on the World Wide Web today spans multitudes of inherently overlapping topics, and it is difficult for any information retrieval system to decide effectively on the relevance of the information retrieved in response to an information seeker's query. For example, the information seeker who wishes to use WWW to learn about a cure for a certain illness would receive a more relevant answer if the search engine was optimized into such domains of topics. This is what is being referred to in the WWW nomenclature as a 'specialized search'. This thesis maintains that the information seeker's search is not intended to be completely random and therefore tends to portray itself as consistent patterns of behaviour. Nonetheless, this behaviour, despite being consistent, can be quite complex to capture. To accomplish this goal the thesis proposes a Multi-Agent Personalized Information Retrieval with Specialization Ontology (MAPIRSO). MAPIRSO offers a complete learning framework that is able to model the end user's search behaviour and interests and to organize information into categorized domains so as to ensure maximum relevance of its responses as they pertain to the end user queries. Specialization and personalization are accomplished using a group of collaborative agents. Each agent employs a Reinforcement Learning (RL) strategy to capture end user's behaviour and interests. Reinforcement learning allows the agents to evolve their knowledge of the end user behaviour and interests as they function to serve him or her. Furthermore, REL allows each agent to adapt to changes in an end user's behaviour and interests. Specialization is the process by which new information domains are created based on existing information topics, allowing new kinds of content to be built exclusively for information seekers. One of the key characteristics of specialization domains is the seeker centric - which allows intelligent agents to create new information based on the information seekers' feedback and their behaviours. Specialized domains are created by intelligent agents that collect information from a specific domain topic. The task of these specialized agents is to map the user's query to a repository of specific domains in order to present users with relevant information. As a result, mapping users' queries to only relevant information is one of the fundamental challenges in Artificial Intelligent (AI) and machine learning research. Our approach employs intelligent cooperative agents that specialize in building personalized ontology information domains that pertain to each information seeker's specific needs. Specializing and categorizing information into unique domains is one of the challenge areas that have been addressed and various proposed solutions were evaluated and adopted to address growing information. However, categorizing information into unique domains does not satisfy each individualized information seeker. Information seekers might search for similar topics, but each would have different interests. For example, medical information of a specific medical domain has different importance to both the doctor and patients. The thesis presents a novel solution that will resolve the growing and diverse information by building seeker centric specialized information domains that are personalized through the information seekers' feedback and behaviours. To address this challenge, the research examines the fundamental components that constitute the specialized agent: an intelligent machine learning system, user input queries, an intelligent agent, and information resources constructed through specialized domains. Experimental work is reported to demonstrate the efficiency of the proposed solution in addressing the overlapping information growth. The experimental work utilizes extensive user-centric specialized domain topics. This work employs personalized and collaborative multi learning agents and ontology techniques thereby enriching the queries and domains of the user. Therefore, experiments and results have shown that building specialized ontology domains, pertinent to the information seekers' needs, are more precise and efficient compared to other information retrieval applications and existing search engines.

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