629 research outputs found

    A novel multi-level and community-based agent ecosystem to support customers dynamic decision-making in smart grids

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    Electrical systems have evolved at a fast pace over the past years, particularly in response to the current environmental and climate challenges. Consequently, the European Union and the United Nations have encouraged the development of a more sustainable energy strategy. This strategy triggered a paradigm shift in energy consumption and production, which becoming increasingly distributed, resulted in the development and emergence of smart energy grids. Multi-agent systems are one of the most widely used artificial intelligence concepts in smart grids. Both multi-agent systems and smart grids are distributed, so there is correspondence between the used technology and the network's complex reality. Due to the wide variety of multi-agent systems applied to smart grids, which typically have very specific goals, the ability to model the network as a whole may be compromised, as communication between systems is typically non-existent. This dissertation, therefore, proposes an agent-based ecosystem to model smart grids in which different agent-based systems can coexist. This dissertation aims to conceive, implement, test, and validate a new agent-based ecosystem, entitled A4SG (agent-based ecosystem for smart grids modelling), which combines the concepts of multi-agent systems and agent communities to enable the modelling and representation of smart grids and the entities that compose them. The proposed ecosystem employs an innovative methodology for managing static or dynamic interactions present in smart grids. The creation of a solution that allows the integration of existing systems into an ecosystem, enables the representation of smart grids in a realistic and comprehensive manner. A4SG integrates several functionalities that support the ecosystem's management, also conceived, implemented, tested, and validated in this dissertation. Two mobility functionalities are proposed: one that allows agents to move between physical machines and another that allows "virtual" mobility, where agents move between agent communities to improve the context for the achievement of their objectives. In order to prevent an agent from becoming overloaded, a novel functionality is proposed to enable the creation of agents that function as extensions of the main agent (i.e., branch agents), allowing the distribution of objectives among the various extensions of the main agent. Several case studies, which test the proposed services and functionalities individually and the ecosystem as a whole, were used to test and validate the proposed solution. These case studies were conducted in realistic contexts using data from multiple sources, including energy communities. The results indicate that the used methodologies can increase participation in demand response events, increasing the fitting between consumers and aggregators from 12 % to 69 %, and improve the strategies used in energy transaction markets, allowing an energy community of 50 customers to save 77.0 EUR per week.Os últimos anos têm sido de mudança nos sistemas elétricos, especialmente devido aos atuais desafios ambientais e climáticos. A procura por uma estratégia mais sustentável para o domínio da energia tem sido promovida pela União Europeia e pela Organização das Nações Unidas. A mudança de paradigma no que toca ao consumo e produção de energia, que acontece, cada vez mais, de forma distribuída, tem levado à emergência das redes elétricas inteligentes. Os sistemas multi-agente são um dos conceitos, no domínio da inteligência artificial, mais aplicados em redes inteligentes. Tanto os sistemas multi-agente como as redes inteligentes têm uma natureza distribuída, existindo por isso um alinhamento entre a tecnologia usada e a realidade complexa da rede. Devido a existir uma vasta oferta de sistemas multi-agente aplicados a redes inteligentes, normalmente com objetivos bastante específicos, a capacidade de modelar a rede como um todo pode ficar comprometida, porque a comunicação entre sistemas é, geralmente, inexistente. Por isso, esta dissertação propõe um ecossistema baseado em agentes para modelar as redes inteligentes, onde vários sistemas de agentes coexistem. Esta dissertação pretende conceber, implementar, testar, e validar um novo ecossistema multiagente, intitulado A4SG (agent-based ecosystem for smart grids modelling), que combina os conceitos de sistemas multi-agente e comunidades de agentes, permitindo a modelação e representação de redes inteligentes e das suas entidades. O ecossistema proposto utiliza uma metodologia inovadora para gerir as interações presentes nas redes inteligentes, sejam elas estáticas ou dinâmicas. A criação de um ecossistema que permite a integração de sistemas já existentes, cria a possibilidade de uma representação realista e detalhada das redes de energia. O A4SG integra diversas funcionalidades, também estas concebidas, implementadas, testadas, e validadas nesta dissertação, que suportam a gestão do próprio ecossistema. São propostas duas funcionalidades de mobilidade, uma que permite aos agentes mover-se entre máquinas físicas, e uma que permite uma mobilidade “virtual”, onde os agentes se movem entre comunidades de agentes, de forma a melhorar o contexto para a execução dos seus objetivos. É também proposta uma nova funcionalidade que permite a criação de agentes que funcionam como uma extensão de um agente principal, com o objetivo de evitar a sobrecarga de um agente, permitindo a distribuição de objetivos entre as várias extensões do agente principal. A solução proposta foi testada e validada por vários casos de estudo, que testam os serviços e funcionalidades propostas individualmente, e o ecossistema como um todo. Estes casos de estudo foram executados em contextos realistas, usando dados provenientes de diversas fontes, tais como comunidades de energia. Os resultados demonstram que as metodologias utilizadas podem melhorar a participação em eventos de demand response, subindo a adequação entre consumidores e agregadores de 12 % para 69 %, e melhorar as estratégias utilizadas em mercados de transações de energia, permitindo a uma comunidade de energia com 50 consumidores poupar 77,0 EUR por semana

    CUTANEOUS ANGIOLEIOMYOSARCOMA IN A DOG

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    A 6 year-old male Labrador Retriever presented with a slow growing subcutaneous tumor in the elbow that mimetized a hygroma. Histologically the tumor consisted of a multinodular mass of spindle cells proliferating from the muscular layer of the subcutaneous vessels. Tumor cells stained positively for alpha-smooth muscle actin and vimentin but were negative for desmin and S-100. The diagnosis was cutaneous angioleiomyosarcoma. 

    Contract-program evaluation: impact of the DRG classification system on hospitals' outputs

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    A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsThe present work project aims at evaluating the impact of contract-program implementation in 2003 and of incentives created in 2007 on hospital output, under the DRG inpatient classification system. A sample of five Portuguese acute public district hospitals was chosen as sample, between 2002 and 2007. Results of hypothesis testing shows positive significant effects on decreasing average lengths of stay, despite significant average age and case-mix increases verified after 2002. Increasing rates of elective outpatient surgeries were also proved significant. Effects of the introduction of 25 new medical outpatient DRG prices in 2007 were proven significant, even if a clear trend was not observable in terms of increases on outpatient discharges, exception made for DRG 410 (chemotherapy). Regression analysis, aiming at detecting upcoding effects in 109 DRG pairs, showed sensitiveness of fraction of the most complicated DRG on each pair to positive changes in DRG prices, for 3 out of 5 hospitals. However, average negative price changes verified for the considered timeframe cancelled expected upcoding effects

    Vascular changes in healthy youngsters with and without influence of oral contraception

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    INTRODUCTION: Cardiovascular diseases are one of the leading causes of mortality worldwide. It is known to have a reduced incidence in premenopausal women compared to the opposite sex. This appears to be related to the female hormones and their fluctuation throughout the menstrual cycle. Objectives: To evaluate and correlate behavior patterns of cerebral dynamics and arterial reactivity throughout the menstrual cycle and to identify possible differences caused by the use of oral contraceptives (OC). METHODS: The sample consisted of 21 healthy, eumenorrheic and non-smoking young womens, belonging to the 18-21 age group. There were two distinct groups: 11 in the group without oral contraceptive (SCO) and 10 in the oral contraceptive group (CCO). Both groups performed an evaluation in the menstrual phase (MP), from the 1st to the 4th day, and in the ovulatory phase (OP), from the 12th to the 16th day. The third evaluation was performed in the late luteal phase (LLP) from the 26th to the 30th day, in the SCO group and in the OC pause, from the 21st to the 28th day, in the CCO group. Four noninvasive procedures were performed: blood pressure measurement, axillary temperature, carotid and right brachial artery sonography. RESULTS: There were no statistically significant differences in carotid parameters, however, there were variations in the velocity of the systolic peak (VPS) of the common carotid artery (CCA) and internal carotid artery (ICA) and the ICA resistance index (IR), throughout the cycle. The SCO group showed a significant increase in FMD from MF to OF (p = 0.023), decreasing in LL (p = 0.012). The CCO group demonstrated a relative stabilization of FMD values. In OP, there were statistically significant differences between the two groups in relation to the FMD value (p = 0.040). CONCLUSIONS: Cyclic fluctuations of estrogen appear to influence cerebral vascular impedance and arterial reactivity but in different proportions. In conclusion, this study supports the idea of standardizing the timing of vascular testing in a premenopausal woman.info:eu-repo/semantics/publishedVersio

    Determinants for the commitment relationship maintenance between the alumni and the alma mater

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    This study aims to find determinants for the commitment relationship between alumni and alma mater. Based on the literature, satisfaction and image are proposed as drivers of commitment. A survey applied to 2544 alumni in a Portuguese university provides data analyzed through a structural equation modeling technique. The results present 'image of education', 'image of communication' and 'satisfaction with social and academic environment' as determinants of the commitment relationship, which provide important clues for the marketers' decision-making process when developing activities geared towards alumni. This process should emphasize aspects relating to their willingness to give back, academic and relationship quality, and institutional values. Within the Higher Education market, this study underscores the need to maintain and reinforce the relationship with alumni, and contributes to the scarce Portuguese literature on alumni matters.info:eu-repo/semantics/publishedVersio

    Textile moisture sensor matrix for monitoring of disabled and bed-rest patients

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    This paper presents the development of a moisture sensor matrix based on textile materials provided with conductive yarns. The measurement principle is based on the measurement of electrical resistance of the textile. The main purpose of this work is to support research on the prevention of pressure ulcers in people committed to bed rest or using wheelchairs. In the first stage of development, the project is studying the relation between physical parameters, exposure time and the levels of discomfort and pain experienced by the patients. In a later stage, the underlying measurement and evaluation principles will be used to develop single sensors or sensor matrixes to be connected to active patient monitoring systems able to warn in situations of excess of moisture and/or pressure (produced by sweat, open wounds, incontinence, etc.).Fundação para a Ciência e a Tecnologia (FCT) - PTDC/SAU-BEB/68678/200

    Smart Grid Ecosystem Modeling Using a Novel Framework for Heterogenous Agent Communities

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    The modeling of smart grids using multi-agent systems is a common approach due to the ability to model complex and distributed systems using an agent-based solution. However, the use of a multi-agent system framework can limit the integration of new operation and management models, especially artificial intelligence algorithms. Therefore, this paper presents a study of available open-source multi-agent systems frameworks developed in Python, as it is a growing programming language and is largely used for data analytics and artificial intelligence models. As a consequence of the presented study, the authors proposed a novel open-source multi-agent system framework built for smart grid modeling, entitled Python-based framework for heterogeneous agent communities (PEAK). This framework enables the use of simulation environments but also allows real integration at pilot sites using a real-time clock. To demonstrate the capabilities of the PEAK framework, a novel agent ecosystem based on agent communities is shown and tested. This novel ecosystem, entitled Agent-based ecosystem for Smart Grid modeling (A4SG), takes full advantage of the PEAK framework and enables agent mobility, agent branching, and dynamic agent communities. An energy community of 20 prosumers, of which six have energy storage systems, that can share energy among them, using a peer-to-peer market, is used to test and validate the PEAK and A4SG solutions.The authors acknowledge the work facilities and equipment provided by the GECAD research center (UIDB/00760/2020) to the project team.info:eu-repo/semantics/publishedVersio

    LOUCOS INTERNADOS E CIDADÃOS LIVRES: UMA LEITURA DA CIDADE A PARTIR DAS CONCEPÇÕES DE LOUCURA EM PRONTUÁRIOS MÉDICOS

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     Não obstante os ideais que lhe querem organizado e limpo, o ambiente urbano se apresenta como lugar de disputas, querelas, distúrbios e crises. Fundado sob as bases de Babel, as cidades se configuram como lugar que mistura toda a sorte dos humanos: para elas acorrem todos aqueles que buscam melhores condições de vida e muitos, apesar dos esforços, acabam encontrando sua degradação. Fazemos, por este artigo, uma breve incursão pela cidade, optando por uma porta degradada: o manicômio judiciário – lugar de prisão perpétua –, onde os prisioneiros, em função da gravidade de seus crimes, não são submetidos à ordem jurídica simplesmente, mas encontram-se aprisionados por duplas grades: o discurso da Justiça e o discurso médico que, a seu modo, envolvem o delinquente em sua lógica, revelando aspectos obscuros da razão.Palavras-chave: Cidade; Subúrbio; Razão; Delinquência; Manicômios.
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