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Semantic Service management for service-oriented MASDel Val Noguera, Elena 08 March 2013 (has links)
Actualmente, los sistemas informáticos complejos se describen en términos de entidades que actúan como proveedores y consumidores. Estas entidades ofrecen su funcionalidad a través de servicios e interactúan entre ellas para ofrecer o pedir estos servicios. La integración de Sistemas Multi-Agente Abiertos y de Sistemas Orientados a Servicios es adecuada para implementar este tipo de sistemas. En los SMA abiertos, los agentes entran y salen del sistema, interactúan con los demás de una manera flexible, y se consideran como entidades reactivas y proactivas, capaces de razonar acerca de lo que sucede en su entorno y llevar a cabo acciones locales sobre la base de sus observaciones para alcanzar sus metas. El área de la computación orientada a servicios proporciona los bloques de construcción básicos para aplicaciones empresariales complejas que son los servicios. Los servicios son independientes de la plataforma y pueden ser descubiertos y compuestos de manera dinámica. Estas características hacen que los servicios sean adecuados para hacer frente a la elevada tasa de cambios en las demandas de las empresas.
Sin embargo, la complejidad de los sistemas informáticos, los cambios en las condiciones del entorno y el conocimiento parcial de los agentes sobre el sistema requieren que los agentes cuenten con mecanismos que les faciliten tareas como el descubrimiento de servicios, la auto-organización de sus relaciones estructurales conforme se producen cambios en la demanda de servicios, y la promoción y mantenimiento de un comportamiento cooperativo entre los agentes para garantizar el buen desarrollo de la actividad de descubrimiento de servicios en el sistema.
La principal aportación de esta tesis doctoral es la propuesta de un marco para Sistemas Multi-Agente Abiertos Orientados a Servicios. Este marco integra agentes que se encuentran en una red sin ningún tipo de estructura predefinida, y agentes que además de estar en esa red forman parte de grupos dinámicos más comp / Del Val Noguera, E. (2013). Semantic Service management for service-oriented MAS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/27556
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Cooperative Payload Transportation by UAVs: A Model-Based Deep Reinforcement Learning (MBDRL) ApplicationKhursheed, Shahwar Atiq 20 August 2024 (has links)
We propose a Model-Based Deep Reinforcement Learning (MBDRL) framework for collaborative paylaod transportation using Unmanned Aerial Vehicles (UAVs) in Search and Rescue (SAR) missions, enabling heavier payload conveyance while maintaining vehicle agility.
Our approach extends the single-drone application to a novel multi-drone one, using the Probabilistic Ensembles with Trajectory Sampling (PETS) algorithm to model the unknown stochastic system dynamics and uncertainty. We use the Multi-Agent Reinforcement Learning (MARL) framework via a centralized controller in a leader-follower configuration. The agents utilize the approximated transition function in a Model Predictive Controller (MPC) configured to maximize the reward function for waypoint navigation, while a position-based formation controller ensures stable flights of these physically linked UAVs. We also developed an Unreal Engine (UE) simulation connected to an offboard planner and controller via a Robot Operating System (ROS) framework that is transferable to real robots. This work achieves stable waypoint navigation in a stochastic environment with a sample efficiency following that seen in single UAV work.
This work has been funded by the National Science Foundation (NSF) under Award No.
2046770. / Master of Science / We apply the Model-Based Deep Reinforcement Learning (MBDRL) framework to the novel application of a UAV team transporting a suspended payload during Search and Rescue missions.
Collaborating UAVs can transport heavier payloads while staying agile, reducing the need for human involvement. We use the Probabilistic Ensemble with Trajectory Sampling (PETS) algorithm to model uncertainties and build on the previously used single UAVpayload system. By utilizing the Multi-Agent Reinforcement Learning (MARL) framework via a centralized controller, our UAVs learn to transport the payload to a desired position while maintaining stable flight through effective cooperation. We also develop a simulation in Unreal Engine (UE) connected to a controller using a Robot Operating System (ROS) architecture, which can be transferred to real robots. Our method achieves stable navigation in unpredictable environments while maintaining the sample efficiency observed in single UAV scenarios.
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Domain independent multi-agent and noise overworld map creationSimonsson, Axel, Ekblad, Joakim January 2024 (has links)
This thesis explores the possibility of combining a noise-based terrain generator with a multi-agent system-based citygenerator for use in overworld map generation for games.The resulting artifact is a generator capable of creating awide variety of landscapes and populating them with citiesthat take advantage of available space and resources. Thegenerated noise is used as a height map which is colorizedto form the basis of the terrain. City agents traverse the space, looking for an optimal place to settle within their view. Once they find their final position, each city creates a number of building agents based on the nearby resources. The city agents take each other and the terrain into account when deciding where the buildings shall be placed. Then, road agents connectfirst the houses, then the cities together. Lastly, points ofinterests such as dungeons, bandit camps and wizard towers are placed, their final positions determined in a similar fashion to the city agents. The analysis of the results indicate that the generator is capable of producing novel terrain, and cities that adapt somewhat well to their surroundings, but offer little variety in existing features from map to map. In addition, more control is necessary to implement the artifact into adevelopment workflow. Respondents rated the maps produced by the generator lower than a map from an existing game ,converted into a similar format, and on a similar level as another map, also from an existing game.
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Formation Control of Multi-Agent SystemsMukherjee, Srijita 08 1900 (has links)
Formation control is a classical problem and has been a prime topic of interest among the scientific community in the past few years. Although a vast amount of literature exists in this field, there are still many open questions that require an in-depth understanding and a new perspective. This thesis contributes towards exploring the wide dimensions of formation control and implementing a formation control scheme for a group of multi-agent systems. These systems are autonomous in nature and are represented by double integrated dynamics. It is assumed that the agents are connected in an undirected graph and use a leader-follower architecture to reach formation when the leading agent is given a velocity that is piecewise constant. A MATLAB code is written for the implementation of formation and the consensus-based control laws are verified. Understanding the effects on formation due to a fixed formation geometry is also observed and reported. Also, a link that describes the functional similarity between desired formation geometry and the Laplacian matrix has been observed. The use of Laplacian matrix in stability analysis of the formation is of special interest.
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Control of the feeder for a reconfigurable assembly systemKruger, Karel 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This thesis documents the research conducted into the control of the feeder subsystem of a Reconfigurable Assembly System (RAS). The research was motivated by a new set of modern manufacturing requirements associated with an aggressive and dynamic global market. The motivation can be more specifically attributed to the need for selective automation, through the installation of reconfigurable systems, in the South African manufacturing industry.
The objective of the research was to implement and evaluate Multi-Agent Systems (MASs) and IEC 61499 function block systems as potential control strategies for reconfigurable systems. The control strategies were implemented for the control of the feeder subsystem of an experimental RAS at Stellenbosch University. The subsystem's hardware consisted of a singulation unit with a machine vision camera, part magazines and a six DOF pick-'n-place robot.
The structure of the control strategies is based on the ADACOR holonic reference architecture. The mapping of the subsystem holons to the structures of the control strategies is explained. The development and implementation of the control strategies, along with the accompanying lower level software, is described in detail.
A system reconfigurability assessment was performed and the results are discussed. The assessment was performed at two levels – the Higher Level Control (HLC) (where the control strategies were implemented) and the low level control and hardware. The assessment was done through four reconfiguration experiments. The evaluation of the HLC was done through both quantitative and qualitative performance measures. The implications of the reconfiguration, involved in each of the respective experiments, on the low level software and hardware are discussed.
The experimental results show that agent-based control adds more reconfigurability to the feeder subsystem than IEC 61499 function block control, and that agents have more advantages regarding customizability, convertibility and scalability than IEC 61499 function blocks. Also, the ability of agent-based control to implement reconfiguration changes during subsystem operation makes it more suitable to the case study application. / AFRIKAANSE OPSOMMING: Hierdie tesis dokumenteer die navorsing gedoen in die beheer van die voerder sub-stelsel vir 'n herkonfigureerbare monteringstelsel. Die navorsing was gemotiveer deur „n nuwe stel vereistes vir moderne vervaardiging wat met 'n aggresiewe en dinamiese globale mark geassosieer word. Die motivering kan meer spesifiek toegeskryf word aan die behoefte tot selektiewe outomatisasie, deur middel van die implimentering van herkonfigureerbare stelsels, in the Suid-Afrikaanse vervaardigingsnywerheid.
Die doel van die navorsing is om multi-agent stelsels en IEC 61499 funksie-blok stelsels, as potensiële beheerstrategiëe vir herkonfigureerbare stelsels, te implementer en evalueer. Die beheerstrategiëe was geïmplementeer vir die voerder sub-stelsel van „n eksperimentele herkonfigureerbare monteringstelsel by Universiteit Stellenbosch. Die hardeware behels „n skeier-eenheid (singulation unit) met „n masjienvisie kamera, onderdeelmagasyne en „n ses-vryheidsgraad gearktikuleerde optel-en-plaas robot.
Die struktuur van die beheerstrategiëe is gebaseer op die ADACOR holoniese verwysingsargitektuur. Die afbeelding van die sub-stelsel holons na die struktuur van die beheerstrategiëe word verduidelik. Die ontwikkeling en implementering van die beheerstrategiëe, asook die gepaardgaande laer-vlak programmatuur, word in detail beskryf.
Die stelsel se herkonfigureerbaarheid was geassesseer en die resultate daarvan word bespreek. Die assessering was op twee vlakke gedoen – die hoër-vlak beheer (waar die beheerstrategiëe geimplementeer was) en die lae-vlak beheer en hardeware. Die assessering was gedoen deur middel van vier herkonfigurasie eksperimente. Die hoër-vlak beheer was geëvalueer deur beide kwalitatiewe en kwantitatiewe metings. Die implikasies van die herkonfigurasie, betrokke by die onderskeie eksperimente, op die lae-vlak beheer en hardeware word beskryf.
Die eksperimentele resultate wys dat agent-baseerde beheer meer herkonfigureerbaarheid tot die voerder sub-stelsel toevoeg as IEC 61499 funksie-blok beheer. Dit is geïdentifiseer dat agente meer voordele inhou ten opsigte van aanpasbaarheid, skakelbaarheid en skaalbaarheid as IEC funksie-blokke. Agent-baseerde beheer laat ook toe dat herkonfigurasieveranderinge tydens sub-stelsel werking geïmplimenteer kan word – dus is dit meer geskik vir aanwending in die gevallestudie.
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Un système multi-agents à base de composants pour l’adaptation autonomique au contexte – Application à la domotique / Component based multi-agent system for autonomic adaptation to the context - Application to home automationHamoui, Mohamad Fady 13 December 2010 (has links)
Les environnements domotiques sont des environnements ubiquitaires dans lesquels des équipements domestiques, disséminés dans une habitation, fournissent des services utilisables à distance au travers d'un réseau. Des systèmes domotiques sont proposés pour permettre aux utilisateurs de contrôler les équipements en fonction de leurs besoins.Idéalement, ces systèmes orchestrent l'exécution des services fournis par les équipements pour réaliser des services complexes. Mieux encore, ces systèmes doivent s'adapter à la variété des environnements en termes d'équipements et des besoins des utilisateurs. Ils doivent également pouvoir s'adapter dynamiquement, si possible de manière autonome, au changement de leur contexte d'exécution (apparition ou disparition d'un équipement, évolution des besoins).Dans cette thèse, nous apportons une réponse à cette problématique avec SAASHA, un système domotique multi-agents à base de composants. La combinaison de ses deux paradigmes permet de gérer l'adaptation à trois niveaux : présentation (interfaces utilisateur),organisation (architecture du système) et comportement (architecture interne des agents).Les agents perçoivent le contexte et ses changements. Les utilisateurs se voient proposer une vue dynamique du contexte leur permettant de définir des scénarios personnalisés sous forme de règles. Les agents se répartissent les rôles pour réaliser les scénarios. Ils modifient dynamiquement leur architecture interne grâce à la génération, au déploiement et à l'assemblage de composants pour se doter de nouveaux comportements de contrôle des équipements et des scénarios. Les agents collaborent ainsi pour exécuter les scénarios. En cas de changement, ces trois niveaux d'adaptation sont mis en oeuvre de manière dynamique et autonome pour maintenir la continuité de service. Un prototype de SAASHA, basé sur les standards industriels UPnP et OSGi, a été développé pour évaluer la faisabilité de notre proposition. / Home automation environments are ubiquitous environments where domestic devices, scattered throughout a home, provide services that can be used remotely over a network. Home automation systems are proposed to enable the users of controlling the devices according to their needs. Ideally, these systems orchestrate the execution of the services provided by the devices to achieve complex services. Even more, these systems must adapt to the variety of environments in terms of devices and users needs. They must also be able to adapt dynamically, if possible in an autonomous manner, to the changes of their execution context (appearance or disappearance of a device, changing needs).In this thesis, we provide an answer to this problematic with SAASHA, a multi-agent home automation system based on components. The combination of these two paradigms enables managing the adaptation on three levels: presentation (user interface), organization (system architecture) and behavior (internal architecture of agents). The agents perceive their context and its changes. The Users are offered a dynamic view of the context allowing them to define custom scenarios as rules. The agents divide the roles among them to realize the scenarios. They modify dynamically their internal architecture throughout the generation, deployment and assembly of components to adopt new device control behaviors and scenarios. The agents collaborate to execute the scenarios. In case of a change, these three levels of adaptation are updated dynamically and autonomously to maintain the service continuity. A SAASHA prototype, based on UPnP and OSGi industry standards, has been developed to assess the feasibility of our proposal.
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Analyse d'impacts du lancement de procédés innovants : application des théories multicritères pour une évaluation robuste / Impact analysis of innovative product launched on the market : application of multicriteria and multiagent approachesToledo Rojas, Francisco 04 April 2014 (has links)
Cette recherche se place dans le domaine de l’ingénierie industrielle, plus exactement aux premières étapes du processus d´innovation (Fuzzy Front-End). Aujourd´hui dans un monde globalisé, où la technologie est à la portée de tous, les entreprises cherchent de nouvelles techniques permettant de se distinguer de la concurrence, et offrent de nouveaux et meilleurs produits ou services ; une manière de conserver leurs avantages comparatifs ou d’en acquérir de nouveaux, pour des clients toujours plus exigeants, et dont les besoins changent constamment. Partant de ce constat, l’innovation se définit comme un processus long et continu, au sein duquel s’utilisent différents modèles. Du fait de la complexité du processus, il n’existe pas de modèle unique réunissant tous les besoins des clients. C’est pourquoi le processus d’innovation, implique différents acteurs de l’entreprise et de son environnement. Ces acteurs, dont l’importance varie, sont souvent d’origines diverses et possèdent des compétences variées. Ils ont des besoins différents, et sont soumis à des contraintes de travail différentes (ressources technologiques et financières, réglementations, etc...). Il paraît ainsi essentiel pour l’entreprise de créer un modèle unique, capable d’identifier les besoins de toutes les parties prenantes, avant d’entamer le processus de développement de nouveaux produits. C’est pour l’entreprise une manière de renforcer le processus d’innovation, et de réduire le taux d´échec lors du lancement de nouveaux produits. Ainsi l’objectif de cette étude est de proposer une nouvelle méthode d’analyse des impacts de l’innovation (A.I), afin de permettre aux entreprises d’identifier les besoins dynamiques des acteurs. Celles-ci pourront ainsi mieux définir leurs nouveaux produits et s’adapter plus facilement aux évolutions du marché. Cet outil fait partie d´une méthodologie de gestion des projets innovants, et doit être utilisé avant la définition des caractéristiques fonctionnelles du nouveau produit. Ceci nous ramène aux premières phases du développement, avant la conception du produit, qui comprennent toutes les étapes depuis la définition des besoins et opportunités pour l´innovation, jusqu’à la prise de décision pour le développement du nouveau produit, appelée Fuzzy Front-End. L’apport théorique de notre travail : Il n´existe pas de définition des impacts de l’innovation (I_n), nous avons donc fait un travail bibliographique sur le concept d’impact. Celui-ci a permis d’explorer les différentes définitions d´impact au sein de différentes disciplines (ingénierie, écologie, psychologie, etc.). Nous avons proposé de cette manière, notre propre définition de l’impact adaptée au contexte de l´innovation. Cette recherche bibliographique, nous a aussi permis d’identifier les différents types d´impacts et de justifier l´utilisation de différentes méthodologies. La contribution méthodologique : l’approche proposée pour l´analyse des impacts de l´innovation (A.I) se décompose en deux étapes. La première vise à modéliser l’« écosystème d´innovation », sur la base des relations, de l´importance et des besoins individuels de chacun des acteurs face au nouveau produit. Ceci grâce à une Analyse des Besoins Dynamiques (A.B.D), qui permettra d´obtenir les besoins agrégés permettant de représenter le système complet, sans considérer les possibles perturbations du milieu extérieur ou les impacts de la même innovation. Pour bien identifier et décrire les besoins des acteurs, nous avons basé la méthodologie sur l´observation de leurs activités. Ainsi, nous avons pu identifier les différents besoins des acteurs de l´innovation sur la base de l’analyse RAR (Ressources, Activités, Résultat), ensuite nous avons classifié les besoins grâce au modèle de KANO et ses améliorations réalisées par Tontini. Une méthode originale d’agrégation des besoins de tous les acteurs est proposée.[...] / This research belongs to the industrial engineering field, focusing on the first stages of the innovation process (Fuzzy Front-End). In a globalized world, where the technology is near to everyone, enterprises are looking for new technologies to be different from their competitors, offering new and better products / services as a strategy to keep or acquire new competitive advantages. Moreover, innovation is a large and continuous process, where different management models are used. But, because of the complexity of the process, no general model is suitable for situations and projects. Thus, the innovation process involves different stakeholders from the company and its environment. These individuals come from different origins (field of knowledge), have different needs, abilities, importance and work under different restrictions (technological or financial resources, work rules, etc.). Consequently, it is essential for the enterprise to identify all the needs of the parts involved in the products. And, a model is required in order to identify the stakeholder’s needs before starting design tasks. This model aims at more robustness in the new product development process and at the reduction of the failure rate when launching new products. Thus, the objective of this PhD thesis is to propose a new method to analyze the impact of the innovation, allowing companies to identify the dynamic actors' needs, to improve the definition of their new products and to adapt to the possible changes of the market. This tool is part of an innovative projects management methodology, used before the elaboration of the functional specifications of a new product. This locates the research in the first stages of development called Fuzzy Front-End: before the genesis of the product. Fuzzy front ends integrate among others the opportunity / needs identification for innovation to the development of the new product decision taking. The proposed approach for the innovation impact analysis (A.I) consists of two stages: the first one intends to model an innovation ecosystem, integrating the relations, the importance of each stakeholder and their individual necessities in regard to the new product. Through a Dynamic Needs Analysis (A.B.D) it will be possible to get the global needs, which represent the whole system, without considering the disturbances of the environment or the impact of the same innovation. Thus, the second stage of the model, through the generation of innovation impact scenarios (S.I.I), evaluates the impact of the innovation the new product may face at its market launching. Due to a new product emergence changes emerge: actors’ performance, their interrelations, the importance and their own needs about the product [...]
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[en] SOFTWARE COMPLIANCE ANALYSIS BASED ON SOFTGOAL CATALOG: A MULTI-AGENTS SYSTEMS APPROACH / [pt] ANÁLISE DE CONFORMIDADE DE SOFTWARE COM BASE EM CATÁLOGOS DE REQUISITOS NÃO FUNCIONAIS: UMA ABORDAGEM BASEADA EM SISTEMAS MULTI-AGENTESANDRÉ LUIZ DE CASTRO LEAL 18 March 2015 (has links)
[pt] A análise de requisitos não funcionais (RNF) é um desafio e vem sendo explorado na literatura científica. Tal iniciativa deve-se ao fato da existência do problema de se verificar o uso das operacionalizações desse tipo de requisito no software construído. Nessa tese apresenta-se um método, com técnicas e ferramentas de apoio, que analisam se um software está em conformidade com padrões de RNFs estabelecidos em catálogo como alternativa para o problema de análise de RNF. A estratégia adotada nessa tese utiliza agentes autônomos para análise de conformidade de software em relação a operacionalizações de RNF. Para isso, utiliza uma base de conhecimentos de padrões persistidos em um catálogo. Os resultados parciais são indicativos de que a proposta de solução é aplicável. A avaliação da validade dá-se por demonstração de que um método parcialmente automatizado é eficaz na identificação de conformidades. Um diferencial do trabalho apresentado é a ligação dos RNFs a sua efetiva implementação. Para demonstração da tese aplicou-se e customizou-se uma técnica de padrões de RNFs, baseados em orientação a metas, em estudos de caso de exemplos do cotidiano prático de software. Apresentamos também a construção de um framework de agentes, que operam sob notações XML para identificar conformidades de software em relação a um catálogo de RNF. / [en] The analysis of non-functional requirements (NFR) is a challenge and has been explored in the literature. This initiative is due to the fact of the existence of the problem of analysis the use of the NFRs operationalization in software. In this thesis we present a method, with supporting tools and techniques, that checks, if a software complies with standards of non-functional requirements as described in a catalog, as an alternative to the NFR analysis problem. The strategy adopted in this thesis uses autonomous agents to check software compliance regarding the operationalization of an NFR, by using a knowledge base of patterns persisted in a catalog. Initial results show that the proposed solution is applicable. The evaluation of the validity is given by the demonstration that a partially automated method is effective in identifying compliance. This work differs form others by linking NFRs to their effective implementation. A method based on patterns NFRs was used in common software, as to show the application of the proposed strategy. An agent based framework, working with XML descriptions, for checking software compliance with respect to a NFR catalog was built.
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[en] HIERARCHICAL NEURAL FUZZY MODELS BASED ON REINFORCEMENT LEARNING OF INTELLIGENT AGENTS / [pt] MODELOS NEURO-FUZZY HIERÁRQUICOS COM APRENDIZADO POR REFORÇO PARA MULTI-AGENTES INTELIGENTESMARCELO FRANCA CORREA 20 February 2013 (has links)
[pt] Os benefícios trazidos pela aplicação de Sistemas Multi-Agentes (SMA) são
diversos. Através da computação paralela, agentes podem trabalhar em conjunto para
explorar melhor a estrutura descentralizada de uma determinada tarefa e acelerar sua
conclusão. Além disso, agentes também podem trocar experiências se comunicando,
fornecer alto grau de escalabilidade, através da inclusão de novos agentes quando
necessário, e ainda fazer com que agentes assumam as atividades de outros agentes em
casos de falha. Vários modelos de agentes desenvolvidos até o momento usam o
aprendizado por reforço como algoritmo base no processo de aprendizado. Quando o
agente está inserido em ambientes pequenos ou discretos, os resultados obtidos com o uso
de métodos como Q-learning são satisfatórios. No entanto, quando o ambiente é grande
ou contínuo, o uso de métodos de aprendizado por reforço torna-se inviável, devido à
grande dimensão do espaço de estados. Nos SMA, este problema é consideravelmente
maior, já que a memória necessária passa a crescer exponencialmente com a quantidade
de agentes envolvidos na aplicação. Esta tese teve como finalidade o desenvolvimento de
um novo modelo de aprendizado autônomo para Sistemas Multi-Agentes (SMA) visando
superar estas limitações. O trabalho foi realizado em três etapas principais: levantamento
bibliográfico, seleção e implementação do modelo proposto, e desenvolvimento de estudo
de casos. O levantamento bibliográfico contemplou o estudo de agentes inteligentes e
Sistemas Multi-Agentes, buscando identificar as propriedades e limitações dos algoritmos
já desenvolvidos, as aplicações existentes, e as características desejadas em um SMA. A
seleção e utilização de um modelo neuro-fuzzy hierárquico da família RL-NFH foi
motivada especialmente pela importância de se estender a autonomia e aprendizado de
agentes através do quesito inteligência, e pela sua capacidade de superar limitações
presentes em algoritmos de aprendizado por reforço tradicionais. Inicialmente, ao modelo
anterior foram adicionados os conceitos de satisfatoriedade e não-dominação, com a
finalidade de acelerar o processo de aprendizado do algoritmo. Em seguida, o novo
modelo multi-agente foi criado, viabilizando o desenvolvimento de aplicações de
natureza tanto cooperativa como competitiva, com múltiplos agentes. Os estudos de caso
contemplaram situações distintas de cooperação e competição entre agentes autônomos.
Foram implementadas três aplicações distintas: uma aplicação benckmark do jogo da
presa-predador (Pursuit-Game); um leilão energia elétrica, em que os fornecedores de
energia fazem ofertas para atender à previsão de demanda em um período de tempo
determinado; e uma aplicação na área de gerenciamento de projetos, onde agentes
inteligentes são criados com o objetivo de fornecer estimativas de duração de atividades e
automatizar alguns processos realizados pelo Gerente de Projetos. Em todos os Estudos
de Caso, os resultados foram comparados com técnicas convencionais e/ou com o
desempenho de outros Sistemas Multi-Agente. Os resultados alcançados pelo novo
modelo se mostraram promissores. Os testes evidenciaram que o modelo teve a
capacidade de coordenar as ações entre agentes totalmente autônomos em diferentes
situações e ambientes. Além disso, o novo modelo mostrou-se genérico e flexível,
podendo ser usado no futuro em outras aplicações envolvendo múltiplos agentes. / [en] There are several benefits provided by Multi-Agent Systems (MAS). Through
parallel computing, agents can work together to better explore the decentralized structure
of a given task and speed up its completion. In addition, agents can also exchange
knowledge through communication, provide scalability by adding new agents when
appropriate, and replace troubled agents in cases of failures. A great number of existing
agent models is based on reinforcement learning algorithms for learning. When the agent
works in small or discrete environments, the results obtained with methods such as Qlearning
are satisfactory. However, when the environment is large or continuous
reinforcement learning methods become unfeasible due to the large state space. In MAS,
this problem is considerably greater, since the required memory begins to grow
exponentially with the number of agents involved in the application. The main objective
of this thesis is to develop a new model of autonomous learning for multi-agents in order
to overcome these limitations. The study consisted of three main stages: literature review,
new model development and implementation, and case studies. Literature review
included the study of intelligent agents and Multi-Agent Systems, seeking to identify the
properties and limitations of the algorithms already developed, existing applications, and
desired features in the new MAS. The choice of a neuro-fuzzy hierarchical model of the
family RL-NFH as a basis was especially motivated by the importance of extending the
autonomy and learning of the agents through intelligence. And also, because of its
capacity to overcome some of the limitations present in traditional reinforcement learning
algorithms. Initially, the concepts of satisficing and non-domination were incorporated
into the previous model to accelerate the learning algorithm. Then, the new multi-agent
model was elaborated and implemented, enabling the development of cooperative and
competitive applications, with multiple agents. Case studies have covered different
situations of cooperation and competition between autonomous agents. Three applications
were considered: the Pursuit-Game benckmark game, an electricity auction, where energy
suppliers make offers to meet forecast demand in a given period of time, and an
application in project management area, where intelligent agents are created to provide
activity duration estimates and to automate some processes done usually by the Project
Manager. In all case studies, results were compared with conventional techniques and/or
the performance of other MAS. The results achieved by the new model are encouraging.
The tests showed that the new system has the capacity to coordinate actions between fully
autonomous agents in different situations and environments. Moreover, the new model is
strongly generic and flexible. Due to these properties, it can be used in future in several
other applications involving multiple agents.
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[en] A MODELING LANGUAGE FOR AGENT BASED SYSTEMS / [pt] UMA LINGUAGEM DE MODELAGEM PARA SISTEMAS BASEADOS EM AGENTESRICARDO CHOREN NOYA 20 August 2004 (has links)
[pt] A tecnologia de agentes tem ganho destaque, tanto na
academia quanto na
indústria, no que se refere ao desenvolvimento de sistemas
distribuídos.
Linguagens de modelagem e processos de desenvolvimento
foram criados para
documentar e formalizar o desenvolvimento de sistemas
baseados em agentes.
Entretanto, as linguagens de modelagem existentes ou se
baseiam em noções de
uma tecnologia de desenvolvimento anterior (orientação a
objetos) ou não
possuem artefatos (modelos) que denotam as características
de agência existentes
no sistema. Esta tese propõe uma linguagem de modelagem
para sistemas
baseados em agentes, a LM-SMA, que gera artefatos (modelos)
que mostram a
modelagem de aspectos de agência, tais como adaptação,
aprendizado, interação e
autonomia. A LM-SMA ainda possui artefatos que permitem a
modelagem da
parte do sistema que não é composta por agentes, por meio
de ontologias. / [en] The agent technology is gaining acceptance, both in academy
and industry,
with regards to distributed systems development. Modeling
languages and
development processes were created to formalize the
development of agent based
systems. Nevertheless, existing modeling languages are
either based on previous
development methods (object oriented) or they do not have
artifacts (models) that
show the agency characteristics that exist in a system.
This thesis proposes a
modeling language, for agent based systems, that generates
artifacts that model
agency aspects, such as adaptation, learning, interaction
and autonomy. The
language has artifacts that allow the modeling of the non-
agent part of an agent
based system, using ontology.
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