849 resultados para Artificial intelligence
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Trabalho Final de Mestrado para obteno do grau de Mestre em Engenharia de Redes de Comunicao e Multimdia
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Trabalho Final de Mestrado para obteno do grau de Mestre em Engenharia de Redes de Comunicao e Multimdia
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Trabalho Final de Mestrado para obteno do grau de Mestre Em Engenharia Qumica e Biolgica Ramo de processos Qumicos
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A construction project is a group of discernible tasks or activities that are conduct-ed in a coordinated effort to accomplish one or more objectives. Construction projects re-quire varying levels of cost, time and other resources. To plan and schedule a construction project, activities must be defined sufficiently. The level of detail determines the number of activities contained within the project plan and schedule. So, finding feasible schedules which efficiently use scarce resources is a challenging task within project management. In this context, the well-known Resource Constrained Project Scheduling Problem (RCPSP) has been studied during the last decades. In the RCPSP the activities of a project have to be scheduled such that the makespan of the project is minimized. So, the technological precedence constraints have to be observed as well as limitations of the renewable resources required to accomplish the activities. Once started, an activity may not be interrupted. This problem has been extended to a more realistic model, the multi-mode resource con-strained project scheduling problem (MRCPSP), where each activity can be performed in one out of several modes. Each mode of an activity represents an alternative way of combining different levels of resource requirements with a related duration. Each renewable resource has a limited availability for the entire project such as manpower and machines. This paper presents a hybrid genetic algorithm for the multi-mode resource-constrained pro-ject scheduling problem, in which multiple execution modes are available for each of the ac-tivities of the project. The objective function is the minimization of the construction project completion time. To solve the problem, is applied a two-level genetic algorithm, which makes use of two separate levels and extend the parameterized schedule generation scheme. It is evaluated the quality of the schedules and presents detailed comparative computational re-sults for the MRCPSP, which reveal that this approach is a competitive algorithm.
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This paper proposes a novel agent-based approach to Meta-Heuristics self-configuration. Meta-heuristics are algorithms with parameters which need to be set up as efficient as possible in order to unsure its performance. A learning module for self-parameterization of Meta-heuristics (MH) in a Multi-Agent System (MAS) for resolution of scheduling problems is proposed in this work. The learning module is based on Case-based Reasoning (CBR) and two different integration approaches are proposed. A computational study is made for comparing the two CBR integration perspectives. Finally, some conclusions are reached and future work outlined.
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This paper provides a two-stage stochastic programming approach for the development of optimal offering strategies for wind power producers. Uncertainty is related to electricity market prices and wind power production. A hybrid intelligent approach, combining wavelet transform, particle swarm optimization and adaptive-network-based fuzzy inference system, is used in this paper to generate plausible scenarios. Also, risk aversion is explicitly modeled using the conditional value-at-risk methodology. Results from a realistic case study, based on a wind farm in Portugal, are provided and analyzed. Finally, conclusions are duly drawn.
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Dissertao apresentada para obteno de Grau de Doutor em Bioqumica,Bioqumica Estrutural, pela Universidade Nova de Lisboa, Faculdade de Cincias e Tecnologia
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A quantidade e variedade de contedos multimdia actualmente disponveis cons- tituem um desafio para os utilizadores dado que o espao de procura e escolha de fontes e contedos excede o tempo e a capacidade de processamento dos utilizado- res. Este problema da seleco, em funo do perfil do utilizador, de informao em grandes conjuntos heterogneos de dados complexo e requer ferramentas especficas. Os Sistemas de Recomendao surgem neste contexto e so capazes de sugerir ao utilizador itens que se coadunam com os seus gostos, interesses ou necessidades, i.e., o seu perfil, recorrendo a metodologias de inteligncia artificial. O principal objectivo desta tese demonstrar que possvel recomendar em tempo til contedos multimdia a partir do perfil pessoal e social do utilizador, recorrendo exclusivamente a fontes pblicas e heterogneas de dados. Neste sen- tido, concebeu-se e desenvolveu-se um Sistema de Recomendao de contedos multimdia baseado no contedo, i.e., nas caractersticas dos itens, no historial e preferncias pessoais e nas interaces sociais do utilizador. Os contedos mul- timdia recomendados, i.e., os itens sugeridos ao utilizador, so provenientes da estao televisiva britnica, British Broadcasting Corporation (BBC), e esto classificados de acordo com as categorias dos programas da BBC. O perfil do utilizador construdo levando em conta o historial, o contexto, as preferncias pessoais e as actividades sociais. O YouTube a fonte do histo- rial pessoal utilizada, permitindo simular a principal fonte deste tipo de dados - a Set-Top Box (STB). O historial do utilizador constitudo pelo conjunto de vdeos YouTube e programas da BBC vistos pelo utilizador. O contedo dos vdeos do YouTube est classificado segundo as categorias de vdeo do prprio YouTube, sendo efectuado o mapeamento para as categorias dos programas da BBC. A informao social, que proveniente das redes sociais Facebook e Twit- ter, recolhida atravs da plataforma Beancounter. As actividades sociais do utilizador obtidas so filtradas para extrair os filmes e sries que so, por sua vez, enriquecidos semanticamente atravs do recurso a repositrios abertos de dados interligados. Neste caso, os filmes e sries so classificados atravs dos gneros da IMDb e, posteriormente, mapeados para as categorias de programas da BBC. Por ltimo, a informao do contexto e das preferncias explcitas, atravs da classificao dos itens recomendados, do utilizador so tambm contempladas. O sistema desenvolvido efectua recomendaes em tempo real baseado nas actividades das redes sociais Facebook e Twitter, no historial de vdeos Youtube e de programas da BBC vistos e preferncias explcitas. Foram realizados testes com cinco utilizadores e o tempo mdio de resposta do sistema para criar o conjunto inicial de recomendaes foi 30 s. As recomendaes personalizadas so geradas e actualizadas mediante pedido expresso do utilizador.
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Os avanos nas Interfaces Crebro-mquina, resultantes dos avanos no tratamento de sinal e da inteligncia artificial, esto a permitir-nos aceder atividade cerebral, descodific-la, e usla para comandar dispositivos, sejam eles braos artificiais ou computadores. Isto muito mais importante quando os utilizadores so pessoas que perderam a capacidade de comunicar, embora mantenham as suas capacidades cognitivas intactas. O caso mais extremo desta situao o das pessoas afetadas pela Sndrome de Encarceramento. Este trabalho pretende contribuir para a melhoria da qualidade de vida das pessoas afetadas por esta sndrome, disponibilizando-lhes um meio de comunicao adaptado s suas limitaes. essencialmente um estudo de usabilidade aplicada a um tipo de utilizador extremamente diminudo na sua capacidade de interao. Nesta investigao comeamos por compreender a Sndrome de Encarceramento e as limitaes e capacidades das pessoas afetadas por ela. Abordamos a neuroplasticidade, o que , e em que medida importante para a utilizao das Interfaces Crebro-mquina. Analisamos o funcionamento destas interfaces, e os fundamentos cientficos que o suportam. Finalmente, com todo este conhecimento em mos, investigamos e desenvolvemos mtodos que nos permitissem otimizar as limitadas capacidades do utilizador na sua interao com o sistema, minimizando o esforo e maximizando o desempenho. Foi para o efeito desenhado e implementado um prottipo que nos permitisse validar as solues encontradas.
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Esta dissertao incide sobre o estudo e anlise de uma soluo para a criao de um sistema de recomendao para uma comunidade de consumidores de media e no consequente desenvolvimento da mesma cujo mbito inicial engloba consumidores de jogos, filmes e/ou sries, com o intuito de lhes proporcionar a oportunidade de partilharem experincias, bem como manterem um registo das mesmas. Com a informao adquirida, o sistema rene condies para proceder a sugestes direcionadas a cada membro da comunidade. O sistema atualiza a sua informao mediante as aes e os dados fornecidos pelos membros, bem como pelo seu feedback s sugestes. Esta aprendizagem ao longo do tempo permite que as sugestes do sistema evoluam juntamente com a mudana de preferncia dos membros ou se autocorrijam. O sistema toma iniciativa de sugerir mediante determinadas aes, mas tambm pode ser invocada uma sugesto diretamente pelo utilizador, na medida em que este no precisa de esperar por sugestes, podendo pedir ao sistema que as fornea num determinado momento. Nos testes realizados foi possvel apurar que o sistema de recomendao desenvolvido forneceu sugestes adequadas a cada utilizador especfico, tomando em linha de conta as suas aes prvias. Para alm deste facto, o sistema no forneceu qualquer sugesto quando o histrico destas tinha provado incomodar o utilizador.
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Mestrado em Computao e Instrumentao Mdica
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This paper describes the environmental monitoring / regatta beacon buoy under development at the Laboratory of Autonomous Systems (LSA) of the Polytechnic Institute of Porto. On the one hand, environmentalmonitoring of open water bodies in real or deferred time is essential to assess and make sensible decisions and, on the other hand, the broadcast in real time of position, water and wind related parameters allows autonomous boats to optimise their regatta performance. This proposal, rather than restraining the boats autonomy, fosters the development of intelligent behaviour by allowing the boats to focus on regatta strategy and tactics. The Nautical and Telemetric Application (NAUTA) buoy is a dual mode reconfigurable system that includes communications, control, data logging, sensing, storage and power subsystems. In environmental monitoring mode, the buoy gathers and stores data from several underwater and above water sensors and, in regatta mode, the buoy becomes an active course mark for the autonomous sailing boats in the vicinity. During a race, the buoy broadcasts its position, together with the wind and the water current local conditions, allowing autonomous boats to navigate towards and round the mark successfully. This project started with the specification of the requirements of the dual mode operation, followed by the design and building of the buoy structure. The research is currently focussed on the development of the modular, reconfigurable, open source-based control system. The NAUTA buoy is innovative, extensible and optimises the on board platform resources.
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This paper reports the development of a B2B platform for the personalization of the publicity transmitted during the program intervals. The platform as a whole must ensure that the intervals are filled with ads compatible with the profile, context and expressed interests of the viewers. The platform acts as an electronic marketplace for advertising agencies (content producer companies) and multimedia content providers (content distribution companies). The companies, once registered at the platform, are represented by agents who negotiate automatically the price of the interval timeslots according to the specified price range and adaptation behaviour. The candidate ads for a given viewer interval are selected through a matching mechanism between ad, viewer and the current context (program being watched) profiles. The overall architecture of the platform consists of a multiagent system organized into three layers consisting of: (i) interface agents that interact with companies; (ii) enterprise agents that model the companies, and (iii) delegate agents that negotiate a specific ad or interval. The negotiation follows a variant of the Iterated Contract Net Interaction Protocol (ICNIP) and is based on the price/s offered by the advertising agencies to occupy the viewers interval.
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Decentralised co-operative multi-agent systems are computational systems where conflicts are frequent due to the nature of the represented knowledge. Negotiation methodologies, in this case argumentation based negotiation methodologies, were developed and applied to solve unforeseeable and, therefore, unavoidable conflicts. The supporting computational model is a distributed belief revision system where argumentation plays the decisive role of revision. The distributed belief revision system detects, isolates and solves, whenever possible, the identified conflicts. The detection and isolation of the conflicts is automatically performed by the distributed consistency mechanism and the resolution of the conflict, or belief revision, is achieved via argumentation. We propose and describe two argumentation protocols intended to solve different types of identified information conflicts: context dependent and context independent conflicts. While the protocol for context dependent conflicts generates new consensual alternatives, the latter chooses to adopt the soundest, strongest argument presented. The paper shows the suitability of using argumentation as a distributed decentralised belief revision protocol to solve unavoidable conflicts.
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The ability to solve conflicting beliefs is crucial for multi- agent systems where the information is dynamic, incomplete and dis- tributed over a group of autonomous agents. The proposed distributed belief revision approach consists of a distributed truth maintenance sy- stem and a set of autonomous belief revision methodologies. The agents have partial views and, frequently, hold disparate beliefs which are au- tomatically detected by systems reason maintenance mechanism. The nature of these conflicts is dynamic and requires adequate methodolo- gies for conflict resolution. The two types of conflicting beliefs addressed in this paper are Context Dependent and Context Independent Conflicts which result, in the first case, from the assignment, by different agents, of opposite belief statuses to the same belief, and, in the latter case, from holding contradictory distinct beliefs. The belief revision methodology for solving Context Independent Con- flicts is, basically, a selection process based on the assessment of the cre- dibility of the opposing belief statuses. The belief revision methodology for solving Context Dependent Conflicts is, essentially, a search process for a consensual alternative based on a next best relaxation strategy.