A systematic approach for detecting faults in agent designs

This thesis proposes a mechanism, including automated tool support, for early-phase defect detection by comparing the plan structures of a belief-desire-intention (BDI) agent design against the following: (1) requirement models, specified in terms of scenarios and goals; and (2) agent communication models. The intuition of our approach is to extract sets of possible behaviour runs from the agent-behaviour models and to verify whether these runs conform to the specifications of the system-to-be. The proposed approach in this thesis is applicable at design time and does not require source code. Our approach is based on the Prometheus agent-design methodology but is applicable to other methodologies that support the same notions. We evaluate the proposed verification framework on designs, ranging from student projects to case studies of industry-level projects. Our evaluation demonstrates that even a simple specification developed by relatively experienced developers is prone to defects, and our approach is successful in uncovering most of these defects. In addition, we conduct a scalability analysis of our methods, and the outcomes reveal that our approach can scale when designs grow in size

Uma Arquitetura para Ambientes Virtuaisde Conveniencia-Uma proposta Baseada emSistemas Multiagentes

Nos dias de hoje os sistemas computacionais são povoados por uma variedade de componentes naturais e sintéticos, integrados de forma cada vez mais intensa pelas novas tecnologias como a Internet e redes sem fio. A integração de pessoas, programas e máquinas pode resultar em melhores serviços para pessoas e para a comunidade. Entretanto, esta integração é um desafio, que, por ser novo e cada vez mais presente devido ao grande avanço da capacidade das máquinas, apresenta dificuldades práticas de realização. Para abordar a solução deste desafio, esta tese apresenta uma arquitetura para ambientes dotados de agentes heterogêneos que objetiva a criação de um ambiente denominado Ambiente Virtual de Convivência. O referencial teórico deste trabalho está centrado em Sistemas Multiagente e Ontologias. O Ambiente Virtual de Convivência apóia comunidades virtuais que são compostas, além dos agentes heterogêneos, por um tipo especial de agente denominado clone. A proposta inclui uma ontologia e uma metodologia para aplicação desta arquitetura. Como exemplos da aplicabilidade da arquitetura, ontologia e metodologia propostas, foram desenvolvidos os ambientes Casa Inteligente, destinado à simulação de interação entre pessoas, serviços e aparelhos domésticos, e um ambiente denominado AVAX (Ambiente Virtual para Aprendizagem de Xadrez), destinado a apoiar as interações e a aprendizagem em uma comunidade de praticantes de Xadrez

Intelligent interface agents for biometric applications

This thesis investigates the benefits of applying the intelligent agent paradigm to biometric identity verification systems. Multimodal biometric systems, despite their additional complexity, hold the promise of providing a higher degree of accuracy and robustness. Multimodal biometric systems are examined in this work leading to the design and implementation of a novel distributed multi-modal identity verification system based on an intelligent agent framework. User interface design issues are also important in the domain of biometric systems and present an exceptional opportunity for employing adaptive interface agents. Through the use of such interface agents, system performance may be improved, leading to an increase in recognition rates over a non-adaptive system while producing a more robust and agreeable user experience. The investigation of such adaptive systems has been a focus of the work reported in this thesis. The research presented in this thesis is divided into two main parts. Firstly, the design, development and testing of a novel distributed multi-modal authentication system employing intelligent agents is presented. The second part details design and implementation of an adaptive interface layer based on interface agent technology and demonstrates its integration with a commercial fingerprint recognition system. The performance of these systems is then evaluated using databases of biometric samples gathered during the research. The results obtained from the experimental evaluation of the multi-modal system demonstrated a clear improvement in the accuracy of the system compared to a unimodal biometric approach. The adoption of the intelligent agent architecture at the interface level resulted in a system where false reject rates were reduced when compared to a system that did not employ an intelligent interface. The results obtained from both systems clearly express the benefits of combining an intelligent agent framework with a biometric system to provide a more robust and flexible application

Pervasive handheld computing systems

The technological role of handheld devices is fundamentally changing. Portable computers were traditionally application specific. They were designed and optimised to deliver a specific task. However, it is now commonly acknowledged that future handheld devices need to be multi-functional and need to be capable of executing a range of high-performance applications. This thesis has coined the term pervasive handheld computing systems to refer to this type of mobile device. Portable computers are faced with a number of constraints in trying to meet these objectives. They are physically constrained by their size, their computational power, their memory resources, their power usage, and their networking ability. These constraints challenge pervasive handheld computing systems in achieving their multi-functional and high-performance requirements. This thesis proposes a two-pronged methodology to enable pervasive handheld computing systems meet their future objectives. The methodology is a fusion of two independent and yet complementary concepts. The first step utilises reconfigurable technology to enhance the physical hardware resources within the environment of a handheld device. This approach recognises that reconfigurable computing has the potential to dynamically increase the system functionality and versatility of a handheld device without major loss in performance. The second step of the methodology incorporates agent-based middleware protocols to support handheld devices to effectively manage and utilise these reconfigurable hardware resources within their environment. The thesis asserts the combined characteristics of reconfigurable computing and agent technology can meet the objectives of pervasive handheld computing systems

Optimisation sous contraintes de problèmes distribués par auto-organisation coopérative

Quotidiennement, divers problèmes d'optimisation : minimiser un coût de production, optimiser le parcours d'un véhicule, etc sont à résoudre. Ces problèmes se caractérisent par un degré élevé de complexité dû à l'hétérogénéité et la diversité des acteurs en jeu, à la masse importante des données ainsi qu'à la dynamique des environnements dans lesquels ils sont plongés. Face à la complexité croissante de ces applications, les approches de résolution classiques ont montré leurs limites. Depuis quelques années, la communauté scientifique s'intéresse aux développements de nouvelles solutions basées sur la distribution du calcul et la décentralisation du contrôle plus adaptées à ce genre de problème. La théorie des AMAS (Adaptive Multi-Agents Systems) propose le développement de solutions utilisant des systèmes multi-agents auto-adaptatifs par auto-organisation coopérative. Cette théorie a montré son adéquation pour la résolution de problèmes complexes et dynamiques, mais son application reste à un niveau d'abstraction assez élevé. L'objectif de ce travail est de spécialiser cette théorie pour la résolution de ce genre de problèmes. Ainsi, son utilisation en sera facilitée. Pour cela, le modèle d'agents AMAS4Opt avec des comportements et des interactions coopératifs et locaux a été défini. La validation s'est effectuée sur deux problèmes clés d'optimisation : le contrôle manufacturier et la conception de produit complexe. De plus, afin de montrer la robustesse et l'adéquation des solutions développées, un ensemble de critères d'évaluation permettant de souligner les points forts et faibles des systèmes adaptatifs et de les comparer à des systèmes existants a été défini.We solve problems and make decisions all day long. Some problems and decisions are very challenging: What is the best itinerary to deliver orders given the weather, the traffic and the hour? How to improve product manufacturing performances? etc. Problems that are characterized by a high level of complexity due to the heterogeneity and diversity of the participating actors, to the increasing volume of manipulated data and to the dynamics of the applications environments. Classical solving approaches have shown their limits to cope with this growing complexity. For the last several years, the scientific community has been interested in the development of new solutions based on computation distribution and control decentralization. The AMAS (Adaptive Multi-Agent-Systems) theory proposes to build solutions based on self-adaptive multi-agent systems using cooperative self-organization. This theory has shown its adequacy to solve different complex and dynamic problems, but remains at a high abstraction level. This work proposes a specialization of this theory for complex optimization problem solving under constraints. Thus, the usage of this theory is made accessible to different non-AMAS experts' engineers. Thus, the AMAS4Opt agent model with cooperative, local and generic behaviours and interactions has been defined.This model is validated on two well-known optimization problems: scheduling in manufacturing control and complex product design. Finally, in order to show the robustness and adequacy of the developed solutions, a set of evaluation criteria is proposed to underline the advantages and limits of adaptive systems and to compare them with already existing systems