Mostrando recursos 1 - 20 de 70

  1. Representação semântica de perfil dinâmico de usuários em comunidades de prática

    Pereira, Matheus
    Em comunidades de prática, a aprendizagem ocorre por meio da interação e colaboração constante de seus participantes, o caráter social destes ambientes é fundamental para a construção do conhecimento. Por este motivo, esta dissertação busca compreender a forma como os usuários interagem em comunidades de prática e propõe a estruturação destas informações em torno de um perfil dinâmico de usuário. A aplicação de perfis de usuário neste contexto permite entender o indivíduo, seus interesses e necessidades. A partir da representação dos participantes de comunidades de prática é possível desenvolver sistemas de aprendizagem inteligente, sistemas de recomendação, elementos de gamificação e...

  2. Evaluating immersive approaches to multidimensional information visualization

    Wagner Filho, Jorge Alberto
    The use of novel displays and interaction resources to support immersive data visualization and improve the analytical reasoning is a research trend in Information Visualization. In this work, we evaluate the use of HMD-based environments for the exploration of multidimensional data, represented in 3D scatterplots as a result of dimensionality reduction. We present a new modelling for the evaluation problem in such a context, accounting for the two factors whose interplay determine the impact on the overall task performance: the difference in errors introduced by performing dimensionality reduction to 2D or 3D, and the difference in human perception errors under...

  3. AwARE : an approach for adaptive recommendation of resources

    Machado, Guilherme Medeiros
    Sistemas de recomendação foram propostos no início da década de 1990 com o objetivo de auxiliar seus usuários a lidar com a sobrecarga cognitiva criada com o advento da internet e o aumento constante de documentos. De lá para cá tais sistemas passaram a assumir vários outros papéis, tais como “auxiliar usuários a explorar”, “melhorar a tomada de decisão”, ou até mesmo “entreter”. Para atingir tais novos objetivos, o sistema necessita olhar para características do usuário que auxiliem no entendimento da tarefa desempenhada pelo usuário e como a recomendação pode auxiliar tal tarefa. Nesse sentido, propõe-se nessa tese uma integração...

  4. Adaptação dinâmica do número de threads em aplicações paralelas openMP para otimizar EDP em sistemas embarcados

    Schwarzrock, Janaina
    Aplicações paralelas geralmente são executadas com o máximo número de threads de hardware disponíveis no sistema para maximizar o seu desempenho. Contudo, esta abordagem pode não ser a melhor escolha quando se busca eficiência energética e, em alguns casos, pode até mesmo degradar o desempenho. Desta maneira, o presente trabalho aplica a adaptação dinâmica do número de threads para otimizar o Energy-Delay Product (EDP) de aplicações paralelas OpenMP executadas em sistemas embarcados. Ao contrário de soluções anteriores, que focam em processadores de propósito geral (GPP, do inglês General Purpose Processors), o presente trabalho considera as características intrínsecas de sistemas embarcados,...

  5. Process modeling guidelines : systematic literature review and experiment

    Avila, Diego Toralles
    Process modeling is an indispensable task in the discipline of Business Process Management. The process models created in this task help its readers in to acquiring a higher comprehension of a process, allowing for the discovery of opportunities for its improvement. However, the comprehension of a process model is not guaranteed, as process modeling is a complex task that depends on the proficiency of the process modeler to avoid the creation of badly designed constructs. Process modeling guidelines are an essential tool in this regard, though they are dispersed across the many studies of the literature and not all of...

  6. A novel classification method applied to well log data calibrated by ontology based core descriptions

    Graciolli, Vinicius Medeiros
    A method for the automatic detection of lithological types and layer contacts was developed through the combined statistical analysis of a suite of conventional wireline logs, calibrated by the systematic description of cores. The intent of this project is to allow the integration of rock data into reservoir models. The cores are described with support of an ontology-based nomenclature system that extensively formalizes a large set of attributes of the rocks, including lithology, texture, primary and diagenetic composition and depositional, diagenetic and deformational structures. The descriptions are stored in a relational database along with the records of conventional wireline logs...

  7. Machine learning mode decision for complexity reduction and scaling in video applications

    Grellert, Mateus
    The recent innovations in Machine Learning techniques have led to a large utilization of intelligent models to solve complex problems that are especially hard to compute with traditional data structures and algorithms. In particular, the current research on Image and Video Processing shows that it is possible to design Machine Learning models that perform object recognition and even action recognition with high confidence levels. In addition, the latest progress on training algorithms for Deep Learning Neural Networks was also an important milestone in Machine Learning, leading to prominent discoveries in Computer Vision and other applications. Recent studies have also shown...

  8. A study onshop sceduling problems

    Zubaran, Tadeu Knewitz
    Shop scheduling is a combinatorial optimization type of problem in which we must allocate machines to jobs for specific periods time. A set of constraints defines which schedules are valid, and we must select one that minimizes or maximizes an objective function. In this work we use the makespan, which is the time the last job finishes. The literature contains several studies proposing techniques to solve shop problems such as the job shop and open shop. These problems allow the steps of the production processes to be either fully ordered or not ordered at all. With increasing complexity and size...

  9. A genetic algorithm for fair land allocation

    Gliesch, Alex Zoch
    The goal of agrarian reform projects is the redistribution of farmland from large latifundia to smaller, often family farmers. One of the main problems the Brazilian National Institute of Colonization and Agrarian Reform (INCRA) has to solve is to subdivide a large parcel of land into smaller lots that are balanced with respect to certain attributes. This problem is difficult since it considers several constraints originating from legislation as well as ethical considerations. Current solutions are computer-assisted, but manual, time-consuming and error-prone, leading to rectangular lots of similar areas which are unfair with respect to soil aptitude and access to...

  10. Uma abordagem multinível usando algoritmos genéticos em um comitê de LS-SVM

    Padilha, Carlos Alberto de Araújo
    Há muitos anos, os sistemas de comitê já tem se mostrado um método eficiente para aumentar a acurácia e estabilidade de algoritmos de aprendizado nas décadas recentes, embora sua construção tem uma questão para ser elucidada: diversidade. O desacordo entre os modelos que compõe o comitê pode ser gerado quando eles são contruídos sob diferentes circunstâncias, tais como conjunto de dados de treinamento, configuração dos parâmetros e a seleção dos algoritmos de aprendizado. O ensemble pode ser visto como uma estrutura com três níveis: espaço de entrada, a base de componentes e o bloco de combinação das respostas dos componentes....

  11. Proof of location as a security mechanism for vehicular Ad Hoc networks

    Boeira, Felipe Caye Batalha
    In vehicular communication, nodes periodically share Cooperative Awareness Messages (CAMs) in order to convey information such as identity, velocity, acceleration and position. The positioning of nodes in a vehicular network is a key factor that directly affects how applications operate, being the formation of platoons a major case. In vehicular platooning, a group of vehicles travels closely together and leverages information shared through CAMs to operate lateral and longitudinal control algorithms. While the standardised cryptographic mechanisms counteract threats such as identity hijacking and packet tampering, an internal member who holds valid credentials may still be able to lie about the...

  12. Graph based algorithms to efficiently map VLSI circuits with simple cells

    Matos, Jody Maick Araujo de
    This thesis introduces a set of graph-based algorithms for efficiently mapping VLSI circuits using simple cells. The proposed algorithms are concerned to, first, effectively minimize the number of logic elements implementing the synthesized circuit. Then, we focus a significant effort on minimizing the number of inverters in between these logic elements. Finally, this logic representation is mapped into a circuit comprised of only two-input NANDs and NORS, along with the inverters. Two-input XORs and XNORs can also be optionally considered. As we also consider sequential circuits in this work, flip-flops are taken into account as well. Additionally, with high-effort optimization...

  13. Distributional models of multiword expression compositionality prediction

    Cordeiro, Silvio Ricardo
    Natural language processing systems often rely on the idea that language is compositional, that is, the meaning of a linguistic entity can be inferred from the meaning of its parts. This expectation fails in the case of multiword expressions (MWEs). For example, a person who is a sitting duck is neither a duck nor necessarily sitting. Modern computational techniques for inferring word meaning based on the distribution of words in the text have been quite successful at multiple tasks, especially since the rise of word embedding approaches. However, the representation of MWEs still remains an open problem in the field....

  14. Síntese de fenômenos naturais através do traçado de raios usando "height fields"

    Silva, Franz Josef Figueroa Ferreira da
    A síntese de imagens é uma ferramenta valiosa na compreensão de diversos fenômenos da natureza. Nos últimos anos várias abordagens têm sido propostas para sintetizar tais fenômenos. A grande maioria de tais abordagens têm se centralizado no desenvolvimento de modelos procedurais. Porém, cada uma destas técnicas simula exclusivamente um fenômeno natural. Um dos métodos de síntese de imagens fotorealísticas mais proeminente é denominado de Traçado de Raios (Ray Tracing). Contudo, apesar de produzir imagens de excelente qualidade, este método é computacionalmente muito oneroso. A síntese de fenômenos naturais utilizando-se o traçado de raios é um desafio. É importante que este...

  15. An incremental gaussian mixture network for data stream classification in non-stationary environments

    Diaz, Jorge Cristhian Chamby
    Data stream classification poses many challenges for the data mining community when the environment is non-stationary. The greatest challenge in learning classifiers from data stream relates to adaptation to the concept drifts, which occur as a result of changes in the underlying concepts. Two main ways to develop adaptive approaches are ensemble methods and incremental algorithms. Ensemble method plays an important role due to its modularity, which provides a natural way of adapting to change. Incremental algorithms are faster and have better anti-noise capacity than ensemble algorithms, but have more restrictions on concept drifting data streams. Thus, it is a...

  16. Týr : a dependent type based code transformation for spatial memory safety in LLVM

    Araújo, Vítor Bujés Ubatuba de
    The C programming language does not enforce spatial memory safety: it does not ensure that memory accessed through a pointer to an object, such as an array, actually belongs to that object. Rather, the programmer is responsible for keeping track of allocations and bounds information and ensuring that only valid memory accesses are performed by the program. On the one hand, this provides flexibility: the programmer has full control over the layout of data in memory, and when checks are performed. On the other hand, this is a frequent source of bugs and security vulnerabilities in C programs. A number...

  17. Análise de sentimentos em tíquetes para o suporte de TI

    Blaz, Cássio Castaldi Araújo
    Análise de Sentimentos/Mineração de Opinião é adotada na engenharia de software para questões como usabilidade e sentimentos de desenvolvedores em projetos. Este trabalho propõe métodos para avaliar os sentimentos presentes em tíquetes abertos à área de suporte de TI. Há diversos tipos de tíquetes abertos à TI (e.g. infraestrutura, software), que envolvem erros, incidentes, requisições, etc. O maior desafio é automaticamente distinguir entre a necessidade em si, a qual é intrinsecamente negativa (por exemplo, a descrição de um erro), de um sentimento embutido na descrição. Nossa abordagem automaticamente cria um dicionário de domínio que contém termos que expressam sentimentos no...

  18. The role of heteregeneity in social problem-solving

    Noble, Diego Vrague
    This thesis reviews and investigates social problem-solving with a particular focus on artificial and heterogeneous systems. More specifically, we not only compile and comprehensively examine recent research results, but also discuss future directions in the study of such heterogeneous complex systems. Given their complex nature, such systems often defy analyses. Even computationally simple models can behave unpredictably after a few iterations. Therefore, one central issue in Social Computing is to devise models of social interaction that are amenable to investigation. This way, one can understand the complex relationships among the components and the outcome of the social process. This thesis...

  19. Exact and heuristic methods for heterogeneous assembly line balancing problems of type 2.

    Borba, Leonardo de Miranda
    The difference among workstations is assumed to be negligible in traditional assembly lines. Heterogeneous assembly lines consider the problem of industries in which the task times vary according to some property to be selected for the task. In the Assembly Line Worker Assignment and Balancing Problem (ALWABP), workers are assigned to workstations and according to their abilities, they execute tasks in different amounts of time. In some cases they can even be incapable of executing some tasks. In the Robotic Assembly Line Balancing Problem (RALBP) there are different types of robots and each station must be executed by a robot....

  20. Exact and heuristic methods for heterogeneous assembly line balancing problems of type 2.

    Borba, Leonardo de Miranda
    The difference among workstations is assumed to be negligible in traditional assembly lines. Heterogeneous assembly lines consider the problem of industries in which the task times vary according to some property to be selected for the task. In the Assembly Line Worker Assignment and Balancing Problem (ALWABP), workers are assigned to workstations and according to their abilities, they execute tasks in different amounts of time. In some cases they can even be incapable of executing some tasks. In the Robotic Assembly Line Balancing Problem (RALBP) there are different types of robots and each station must be executed by a robot....

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