Hypothetical answers to continuous queries over data streams

Continuous queries over data streams may suffer from blocking operations and/or unbound wait, which may delay answers until some relevant input arrives through the data stream. These delays may turn answers, when they arrive, obsolete to users who sometimes have to make decisions with no help whatsoever. Therefore, it can be useful to provide hypothetical answers - "given the current information, it is possible that X will become true at time t" - instead of no information at all. In this paper we present a semantics for queries and corresponding answers that covers such hypothetical answers, together with an online algorithm for updating the set of facts that are consistent with the currently available information

Raciocínio adaptativo de base emocional em agentes inteligentes

O projecto e implementação de agentes inteligentes capazes de comportamento eficaz em ambientes reais, onde a incerteza e o dinamismo são generalizados e onde tempo e recursos são limitados, levanta problemas importantes, relacionados quer com a capacidade adaptativa dos agentes, quer com a complexidade computacional dos processos cognitivos envolvidos, em particular de processos de raciocínio e planeamento. Neste artigo são apresentados mecanismos de base emocional que tornam possível a adaptação a ambientes dinâmicos e um uso controlado de recursos, através da focagem dos processos cognitivos. No sentido de avaliar a abordagem proposta são apresentados resultados experimentais em comparação com resultados de outras abordagens de referência.info:eu-repo/semantics/publishedVersio

Previsão eleitoral para a Assembleia da República Portuguesa

Em trabalho anterior utilizaram-se técnicas de Data Mining para predizer resultados eleitorais, sem utilizar sondagens, recorrendo a variáveis socioeconómicas, disponíveis publicamente sobre Portugal, no período abrangido pelas treze eleições para a Assembleia da República, entre 1974 e 2009. No entanto, o espectro político considerado nesse trabalho não abrange os 100% dos votos expressos, mas apenas os quatro partidos com assento parlamentar regular desde 1975 cuja votação atinge cerca de 84%. Na abordagem anteriormente adoptada, cada um dos quatro partidos tradicionais foi tratado separadamente, resultando em previsões independentes. Neste artigo analisa-se a extensão desse trabalho à previsão do intervalo restante dos resultados eleitorais e a sua utilização para garantir a restrição de que a percentagem total de votos expressos soma 100%. Os resultados mostraram que os métodos anteriormente aplicados permitem obter previsões com resultados de qualidade similar para o conjunto das forças partidárias complementares.In earlier work, Data Mining techniques using a large number of public available socioeconomic variables about Portugal were used to predict election results between 1974 and 2009 (thirteen elections) for the Parliament of the Portuguese Republic. However, the political spectrum considered in that work does not cover 100% of the votes cast, but only the four parties with regular parliamentary seat since 1975, whose voting reaches about 84%. In the approach previously adopted, each of the four traditional parties was treated separately resulting in independent forecasts. In this paper we analyse the extension of that work to the forecasting of the remaining interval of the election results and its use to ensure the restriction that the total percentage of votes cast adds up to 100%. The results showed that the methods previously applied allow making predictions with similar quality for the remaining partisan forces

Flexibilidade na comparação multiplicativa : um estudo com alunos do 2.º ciclo

Este estudo incide na aprendizagem da Matemática e tem como objetivo compreender o modo como alunos do 6.º ano desenvolvem a proporcionalidade, no contexto de exploração de tarefas de comparação multiplicativa. Mais especificamente, pretende responder a duas questões. A primeira, surge relacionada com a caracterização da evolução da aprendizagem da comparação multiplicativa; e a segunda, aparece ligada às conexões entre a compreensão dos aspetos proporcionais das estruturas multiplicativas, em particular, dos conceitos de razão e de proporção, e a flexibilidade de estratégias de resolução e de representações utilizadas pelos alunos. A fundamentação teórica apresenta três temáticas: estruturas multiplicativas e raciocínio proporcional, representações na aprendizagem matemática e flexibilidade na aprendizagem matemática. Discutem-se, sob diferentes perspetivas, os conceitos de comparação multiplicativa, razão e proporção. Referem-se os modos de representação e a sua ligação à compreensão destes conceitos. Menciona-se a flexibilidade na construção de estratégias, no uso de representações, na criatividade e, em concreto, na resolução de tarefas de comparação multiplicativa. O estudo segue uma metodologia de investigação baseada em design, na modalidade de experiência de ensino conduzida a partir de uma conjetura, concretizada em dois ciclos de experiência. Os participantes são os alunos de duas turmas do 6.º ano de escolaridade e as respetivas professoras. A análise dos dados permite concluir que existe, nos dois ciclos de experiência, evolução na aprendizagem da comparação multiplicativa. O raciocínio dos alunos é desenvolvido somente dentro de um espaço de medida, mas as suas estratégias de resolução permitem marcar um percurso que se inicia na não quantificação e prossegue para a necessidade de quantificar e de utilizar estratégias aditivas e multiplicativas, apoiadas em representações simbólicas de razão (na forma de fração, tabelas e linhas numéricas duplas). Quando usam estratégias e representações adequadas, os alunos não mostram grande apetência para as alterar. No entanto, ao resolverem as tarefas identifica-se o uso de relações numéricas multiplicativas e de propriedades da operação multiplicação que articulam com as estratégias e as representações a que recorrem.This study focuses on process of learning mathematics and aims to understand how 6th grade students develop proportionality in the context of exploring multiplicative comparison tasks. More specifically, it intends to answer two questions. The first is related to the characterization of the learning trajectory of the multiplicative comparison; and the second is linked to the connections between the understanding of the proportional aspects of the multiplicative structures, the concepts of ratio and proportion, and the flexibility of resolution strategies and representations used by the students. The theoretical framework presents three themes: multiplicative structures and proportional reasoning, representations in mathematical learning and flexibility in mathematical learning. From different perspectives, the concepts of multiplicative comparison, ratio and proportion are discussed. An overview of the modes of representation and their connection to the understanding of these concepts is offered. Moreover, flexibility is discussed in context of construction of strategies, use of representations, creativity, and resolution of multiplicative comparison tasks. The study follows a design-based research methodology, in the modality of teaching experiment conducted from a conjecture, comprised of two cycles of experience. Participants are students from two 6th grade classes and their respective teachers. The analysis of the data allows us to conclude that there is an evolution in the learning of the multiplicative comparison in both cycles of experience. Students' reasoning is only developed within a space of measures, but their resolution strategies make it possible to delineate a path that begins with non-quantification and progresses towards the need to quantify and to use additive and multiplicative strategies, which are supported by symbolic representations of ratio (in the form of fraction, tables and double numeric rows). When using appropriate strategies and representations, students are unwilling to change them. However, when solving the tasks, one identifies the use of multiplicative numerical relations and multiplication operation properties that articulate with the strategies and representations they use

Prevalência de excesso de peso e obesidade nas escolas do primeiro ciclo da Nazaré

Tese de mestrado, Cuidados Farmacêuticos, Universidade de Lisboa, Faculdade de Farmácia, 2014Introdução: Nas últimas décadas, a obesidade tem adquirido proporções epidémicas em todos os grupos etários. Definida pela OMS como uma doença crónica, a sua distribuição e prevalência parece estar associada ao nível sócio-económico, estilos de vida sedentários e hábitos de vida incorrectos. Segundo a DGS, 15% das crianças portuguesas sofrem de obesidade infantil. 1 Objectivos: Este estudo pretendeu determinar a prevalência do excesso de peso e da obesidade, nas crianças dos 6 aos 11 anos, nas escolas do primeiro ciclo do concelho da Nazaré e determinar factores de risco para a ocorrência do excesso de peso. Metodologia: Tratou-se de um estudo descritivo transversal em que os dados foram recolhidos através do preenchimento de um questionário por parte dos encarregados de educação e da avaliação física das crianças. Neste estudo foram convidadas a participar 225 crianças do centro escolar da Nazaré e de Valado dos Frades. Os dados foram tratados em SPSS versão 21, com recurso a estatística descritiva univariada e bivariada, considerando um IC 95%. O estudo foi aprovado pela comissão de ética da FFUL. Resultados e Discussão: O estudo inclui 171 crianças e respectivos encarregados de educação e a prevalência de excesso de peso encontrada foi de 41,5% e de obesidade infantil foi de 24,5%. Verificou-se que o excesso de peso era dependente do género das crianças, sendo mais comum nos rapazes (p=0,026), e dependente de um elevado peso à nascença (p=0,022). Constatou-se que os encarregados de educação tinham percepção distorcida da imagem corporal dos seus educandos. Conclusão: A prevalência de obesidade encontrada neste estudo sugere que existe uma urgente necessidade do desenvolvimento de um plano de combate à obesidade, de modo a prevenir e reverter este problema neste concelho.Introduction: Over the past decades, obesity has been acquiring epidemic proportions across all age groups. Defined by the WHO, as a chronic condition, its prevalence and distribution seems to be associated with sócio-economic strata, sedentary lifestyles and incorrect habits of living. Acording to the DGS, 15% of portuguese children currently suffer from child obesity.1 Objectives: This study aimed to determine the prevalence of overweight and of obesity in children aged 6 to 11, in the first cycle schools of Nazaré and to determine risk factors for the development of overweight. Methodology: A cross-sectional study was developed, where data were collected throught questionnaires headed at the children’s legal responsible and through physical evaluation fo the children. Two hundred and twenty five children from the Nazaré and Valado dos Frades School Centre were invited to participate. Data were analyzed using SPSS version 21, by means of univariate and bivariate descriptive statistics, considering a 95% CI. The study was approved by the Ethics Committee of the FFUL. Results and Discussion: The study included data from 171 children and respective legal responsible. The estimated prevalence of overweight was 41,5% and the prevalence of obesity was 24,5%. Overweight was associated with gender, where it was more commonly found among male (p=0,026), and dependent of a high weight at birth (p=0,022). Children’s legal responsible had a distorced perception of their child’s body image. Conclusion: The prevalence of obesity found in this study suggests there is an urgent need for the development of a plan to fight obesity, so that the problem in this council can still be reverted and future cases prevented

A Social Reasoning Mechanism Based on a New Approach for Coalition Formation

In order to enable an agent to coordinate its activities with other agents and to participate in coalitions, one of the elements to take into account in its conception should be a social reasoning mechanism that allows the agent to reason about the other agents. This paper presents a social reasoning mechanism that extends, in some aspects, the models presented in previous works. Such a model supports the agent's reasoning concerning other agents, using notions of social dependence. In order to deal with concrete situations, where the agent?s knowledge is limited, a new perspective of coalition formation is presented in which the agents may not have knowledge of all the relevant details to realize their goals. The main concepts underlying the proposed social reasoning mechanism are presented, followed by an overview of the respective formal model, and some aspects related to the implementation of a system based on this mode

AutoFocus Framework Documentation

The work presented in this document is part of the project "AutoFocus: Adaptive Self-Improving Multi-Agent Systems" that is being developed at the research unit LabMAg, which objective is the implementation of multi-agent systems based on autonomous entities capable of self-optimized and adaptive behaviors. The notion of autonomic computation, like other notions that also imply pro-active computation, is based on autonomous entities that actively work to achieve their objectives and have the ability to dynamically adjust to changes in their environment, constrained by time and resource limits. In the approach used by the AutoFocus project, that adaptation to change and the regulation of the agent's capabilities, result from the combination of cognitive aspects with emotional based aspects. The agent model defined and used by the AutoFocus project is the Agent Flow Model. The task that corresponded to the work presented in this document was to develop a platform for the Agent Flow Model. It was intended, with this platform, to provide a tool that enables the rapid deployment and monitoring of agents based on this model. The developed work consisted in the analysis and design, oriented to objects, implementation and testing of components of this platform

Patterns for Programming in the Semantic Web

Originally proposed in the mid-90s, design patterns for software development played a key role in object-oriented programming not only in increasing software quality, but also by giving a better understanding of the power and limitations of this paradigm. Since then, several authors have endorsed a similar task for other programming paradigms, in the hope of achieving similar benefits. In this paper we discuss design patterns for the Semantic Web, giving new insights on how existing programming frameworks can be used in a systematic way to design large-scale systems. The common denominator between these frameworks is the combination between different reasoning systems, namely description logics and logic programming. Therefore, we chose to work in a generalization of dl-programs that supports several (possibly different) description logics, expecting that our results will be easily adapted to other existing frameworks such as multi-context systems. This study also suggests new constructs to enforce legibility and internal structure of logic-based Semantic Web programs

Monitoring device of ice formation in evaporator surface of refrigeration systems

In order to achieve lower temperatures than ambient air, whether for food cold storage purposes or thermal comfort, the evaporator coils generally operate at lower temperatures than the freezing point of water. The ice formed on the evaporator surface is disadvantageous for the energy efficiency and performance of the refrigeration system. Thus, its removal is crucial to restore the desired operating conditions. This paper studies the feasibility of using a simple and low cost device for monitoring the ice formation on the surface of evaporators. The concept of the developed device is based on variation imposed by the ice formation on the electrical resistance measured between electrodes. Through a detailed analysis of results, the electronic circuit capable of automating the entire process has been designed and projected on a printed circuit board. The results show that both the circuit configuration and the concept have potential to be used as ice formation monitoring devices. Some adjustments have to be included in the device to achieve a widespread application level.info:eu-repo/semantics/publishedVersio