95 resultados para agent based modeling
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This paper presents MASCEM - a multi-agent based electricity market simulator. MASCEM uses game theory, machine learning techniques, scenario analysis and optimization techniques to model market agents and to provide them with decision-support. This paper mainly focus on the MASCEM ability to provide the means to model and simulate Virtual Power Players (VPP). VPPs are represented as a coalition of agents, with specific characteristics and goals. The paper details some of the most important aspects considered in VPP formation and in the aggregation of new producers and includes a case study based on real data.
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In this paper we present a new methodology, based in game theory, to obtain the market balancing between Distribution Generation Companies (DGENCO), in liberalized electricity markets. The new contribution of this methodology is the verification of the participation rate of each agent based in Nuclolo Balancing and in Shapley Value. To validate the results we use the Zaragoza Distribution Network with 42 Bus and 5 DGENCO.
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Power systems operation in a liberalized environment requires that market players have access to adequate decision support tool, allowing them to consider all the business opportunities and take strategic decisions. Ancillary services represent a good negotiation opportunity that must be considered by market players. For this, decision support tools must include ancillary market simulation. This paper deals with ancillary services negotiation in electricity markets. The proposed concepts and methodologies are implemented in MASCEM, a multi-agent based electricity market simulator. A test case concerning the dispatch of ancillary services using two different methods (Linear Programming and Genetic Algorithm approaches) is included in the paper.
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Electricity market players operating in a liberalized environment requires access to an adequate decision support tool, allowing them to consider all the business opportunities and take strategic decisions. Ancillary services represent a good negotiation opportunity that must be considered by market players. For this, decision support tool must include ancillary market simulation. This paper proposes two different methods (Linear Programming and Genetic Algorithm approaches) for ancillary services dispatch. The methodologies are implemented in MASCEM, a multi-agent based electricity market simulator. A test case based on California Independent System Operator (CAISO) data concerning the dispatch of Regulation Down, Regulation Up, Spinning Reserve and Non-Spinning Reserve services is included in this paper.
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Electricity market players operating in a liberalized environment requires access to an adequate decision support tool, allowing them to consider all the business opportunities and take strategic decisions. Ancillary services represent a good negotiation opportunity that must be considered by market players. For this, decision support tools must include ancillary market simulation. This paper proposes two different methods (Linear Programming and Genetic Algorithm approaches) for ancillary services dispatch. The methodologies are implemented in MASCEM, a multi-agent based electricity market simulator. A test case concerning the dispatch of Regulation Down, Regulation Up, Spinning Reserve and Non-Spinning Reserve services is included in this paper.
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Mestrado em Engenharia Informtica
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Electricity markets are complex environments with very particular characteristics. A critical issue regarding these specific characteristics concerns the constant changes they are subject to. This is a result of the electricity markets restructuring, which was performed so that the competitiveness could be increased, but it also had exponential implications in the increase of the complexity and unpredictability in those markets scope. The constant growth in markets unpredictability resulted in an amplified need for market intervenient entities in foreseeing market behaviour. The need for understanding the market mechanisms and how the involved players interaction affects the outcomes of the markets, contributed to the growth of usage of simulation tools. Multi-agent based software is particularly well fitted to analyze dynamic and adaptive systems with complex interactions among its constituents, such as electricity markets. This dissertation presents ALBidS Adaptive Learning strategic Bidding System, a multiagent system created to provide decision support to market negotiating players. This system is integrated with the MASCEM electricity market simulator, so that its advantage in supporting a market player can be tested using cases based on real markets data. ALBidS considers several different methodologies based on very distinct approaches, to provide alternative suggestions of which are the best actions for the supported player to perform. The approach chosen as the players actual action is selected by the employment of reinforcement learning algorithms, which for each different situation, simulation circumstances and context, decides which proposed action is the one with higher possibility of achieving the most success. Some of the considered approaches are supported by a mechanism that creates profiles of competitor players. These profiles are built accordingly to their observed past actions and reactions when faced with specific situations, such as success and failure. The systems context awareness and simulation circumstances analysis, both in terms of results performance and execution time adaptation, are complementary mechanisms, which endow ALBidS with further adaptation and learning capabilities.
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A massificao da utilizao das tecnologias de informao e da Internet para os mais variados fins, e nas mais diversas reas, criou problemas de gesto das infra-estruturas de informtica, mpares at ao momento. A gesto de redes informticas converteu-se num factor vital para uma rede a operar de forma eficiente, produtiva e lucrativa. No entanto, a maioria dos sistemas so baseados no Simple Network Management Protocol (SNMP), assente no modelo cliente-servidor e com um paradigma centralizado. Desta forma subsiste sempre um servidor central que colecta e analisa dados provenientes dos diferentes elementos dispersos pela rede. Sendo que os dados de gesto esto armazenados em bases de dados de gesto ou Management Information Bases (MIBs) localizadas nos diversos elementos da rede. O actual modelo de gesto baseado no SNMP no tem conseguido dar a resposta exigida. Pelo que, existe a necessidade de se estudar e utilizar novos paradigmas de maneira a que se possa encontrar uma nova abordagem capaz de aumentar a fiabilidade e a performance da gesto de redes. Neste trabalho pretende-se discutir os problemas existentes na abordagem tradicional de gesto de redes, procurando demonstrar a utilidade e as vantagens da utilizao de uma abordagem baseada em Agentes mveis. Paralelamente, prope-se uma arquitectura baseada em Agentes mveis para um sistema de gesto a utilizar num caso real.
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This paper describes a multi-agent brokerage platform for near real time advertising personalisation organised in three layers: user interface, agency and marketplace. The personalisation is based on the classification of viewer profiles and advertisements (ads). The goal is to provide viewers with a personalised advertising alignment during programme intervals. The enterprise interface agents upload new ads and negotiation profiles to producer agents and new user and negotiation profiles to distributor agents. The agency layer is composed of agents that represent ad producer and media distributor enterprises as well as the market regulator. The enterprise agents offer data upload and download operations as Web Services and register the specification of these interfaces at an UDDI registry for future discovery. The market agent supports the registration and deregistration of enterprise delegate agents at the marketplace. This paper addresses the marketplace layer, an agent-based negotiation platform per se, where delegates of the relevant advertising agencies and programme distributors negotiate to create the advertising alignment that best fits a viewer profile and the advertising campaigns available. The whole brokerage platform is being developed in JADE, a multi-agent development platform. The delegate agents download the negotiation profile and upload the negotiation results from / to the corresponding enterprise agent. In the meanwhile, they negotiate using the Iterated Contract Net protocol. All tools and technologies used are open source.
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This paper proposes a novel business model to support media content personalisation: an agent-based business-to-business (B2B) brokerage platform for media content producer and distributor businesses. Distributors aim to provide viewers with a personalised content experience and producers wish to en-sure that their media objects are watched by as many targeted viewers as possible. In this scenario viewers and media objects (main programmes and candidate objects for insertion) have profiles and, in the case of main programme objects, are annotated with placeholders representing personalisation opportunities, i.e., locations for insertion of personalised media objects. The MultiMedia Brokerage (MMB) platform is a multiagent multilayered brokerage composed by agents that act as sellers and buyers of viewer stream timeslots and/or media objects on behalf of the registered businesses. These agents engage in negotiations to select the media objects that best match the current programme and viewer profiles.
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O objectivo da tese demonstrar a adequao do paradigma dos mercados electrnicos baseados em agentes para transaccionar objectos multimdia em funo do perfil dos espectadores. Esta dissertao descreve o projecto realizado no mbito da plataforma de personalizao de contedos em construo. O domnio de aplicao adoptado foi a personalizao dos intervalos publicitrios difundidos pelos distribuidores de contedos multimdia, i.e., pretende-se gerar em tempo til o alinhamento de anncios publicitrios que melhor se adeqe ao perfil de um espectador ou de um grupo de espectadores. O projecto focou-se no estudo e seleco das tecnologias de suporte, na concepo da arquitectura e no desenvolvimento de um prottipo que permitisse realizar diversas experincias nomeadamente com diferentes estratgias e tipos de mercado. A arquitectura proposta para a plataforma consiste num sistema multiagente organizado em trs camadas que disponibiliza interfaces do tipo servio Web com o exterior. A camada de topo constituda por agentes de interface com o exterior. Na camada intermdia encontram-se os agentes autnomos que modelam as entidades produtoras e consumidoras de componentes multimdia assim como a entidade reguladora do mercado. Estes agentes registam-se num servio de registo prprio onde especificam os componentes multimdia que pretendem negociar. Na camada inferior realiza-se o mercado que constitudo por agentes delegados dos agentes da camada superior. O lanamento do mercado efectuado atravs de uma interface e consiste na escolha do tipo de mercado e no tipo de itens a negociar. Este projecto centrou-se na realizao da camada do mercado e da parte da camada intermdia de apoio s actividades de negociao no mercado. A negociao efectuada em relao ao preo da transmisso do anncio no intervalo em preenchimento. Foram implementados diferentes perfis de negociao com tcticas, incrementos e limites de variao de preo distintos. Em termos de protocolos de negociao, adoptou-se uma variante do Iterated Contract Net o Fixed Iterated Contract Net. O prottipo resultante foi testado e depurado com sucesso.
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Mestrado em Engenharia Electrotcnica e de Computadores - rea de Especializao de Telecomunicaes
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No decorrer dos ltimos anos, os agentes (inteligentes) de software foram empregues como um mtodo para colmatar as dificuldades associadas com a gesto, partilha e reutilizao de um crescente volume de informao, enquanto as ontologias foram utilizadas para modelar essa mesma informao num formato semanticamente explcito e rico. medida que a popularidade da Web Semntica aumenta e cada vez informao partilhada sob a forma de ontologias, o problema de integrao desta informao amplifica-se. Em semelhante contexto, no expectvel que dois agentes que pretendam cooperar utilizem a mesma ontologia para descrever a sua conceptualizao do mundo. Inclusive pode revelar-se necessrio que agentes interajam sem terem conhecimento prvio das ontologias utilizadas pelos restantes, sendo necessrio que as conciliem em tempo de execuo num processo comummente designado por Mapeamento de Ontologias [1]. O processo de mapeamento de ontologias normalmente oferecido como um servio aos agentes de negcio, podendo ser requisitado sempre que seja necessrio produzir um alinhamento. No entanto, tendo em conta que cada agente tem as suas prprias necessidades e objetivos, assim como a prpria natureza subjetiva das ontologias que utilizam, possvel que tenham diferentes interesses relativamente ao processo de alinhamento e que, inclusive, recorram aos servios de mapeamento que considerem mais convenientes [1]. Diferentes matchers podem produzir resultados distintos e at mesmo contraditrios, criando-se assim conflitos entre os agentes. necessrio que se proceda ento a uma tentativa de resoluo dos conflitos existentes atravs de um processo de negociao, de tal forma que os agentes possam chegar a um consenso relativamente s correspondncias que devem ser utilizadas na traduo de mensagens a trocar. A resoluo de conflitos considerada uma mtrica de grande importncia no que diz respeito ao processo de negociao [2]: considera-se que existe uma maior confiana associada a um alinhamento quanto menor o nmero de conflitos por resolver no processo de negociao que o gerou. Desta forma, um alinhamento com um nmero elevado de conflitos por resolver apresenta uma confiana menor que o mesmo alinhamento associado a um nmero elevado de conflitos resolvidos. O processo de negociao para que dois ou mais agentes gerem e concordem com um alinhamento denominado de Negociao de Mapeamentos de Ontologias. data existem duas abordagens propostas na literatura: (i) baseadas em Argumentao (e.g. [3] [4]) e (ii) baseadas em Relaxamento [5] [6]. Cada uma das propostas expostas apresenta um nmero de vantagens e limitaes. Foram propostas vrias formas de combinao das duas tcnicas [2], com o objetivo de beneficiar das vantagens oferecidas e colmatar as suas limitaes. No entanto, data, no so conhecidas experincias documentadas que possam provar tal afirmao e, como tal, no possvel atestar que tais combinaes tragam, de facto, o benefcio que pretendem. O trabalho aqui apresentado pretende providenciar tais experincias e verificar se a afirmao de melhorias em relao aos resultados das tcnicas individuais se mantm. Com o objetivo de permitir a combinao e de colmatar as falhas identificadas, foi proposta uma nova abordagem baseada em Relaxamento, que posteriormente combinada com as abordagens baseadas em Argumentao. Os seus resultados, juntamente com os da combinao, so aqui apresentados e discutidos, sendo possvel identificar diferenas nos resultados gerados por combinaes diferentes e possveis contextos de utilizao.
Resumo:
Energy systems worldwide are complex and challenging environments. Multi-agent based simulation platforms are increasing at a high rate, as they show to be a good option to study many issues related to these systems, as well as the involved players at act in this domain. In this scope the authors research group has developed a multi-agent system: MASCEM (Multi- Agent System for Competitive Electricity Markets), which simulates the electricity markets environment. MASCEM is integrated with ALBidS (Adaptive Learning Strategic Bidding System) that works as a decision support system for market players. The ALBidS system allows MASCEM market negotiating players to take the best possible advantages from the market context. This paper presents the application of a Support Vector Machines (SVM) based approach to provide decision support to electricity market players. This strategy is tested and validated by being included in ALBidS and then compared with the application of an Artificial Neural Network, originating promising results. The proposed approach is tested and validated using real electricity markets data from MIBEL - Iberian market operator.