Marcos Sfair Sunyé

Kruskal's Algorithm for Query Tree Optimization

This paper describes an implementation of Kruskals algorithm in query optimization process for generation of a near optimal execution query tree. The open source Post- greSQL DBMS was used in the experiments since its query optimization is performed by dynamic programming and genetic algorithm, which allows a concrete comparison with our approach. Kruskals algorithm presents some advantages like its simplified code, its polynomial-time execution and the reduced search space to generate only one query tree, that will be the optimal tree. In most experiments, Kruskals algorithm got the expected results in almost the same time as the results achieved by default Post- greSQLs optimization algorithms. The results confirm that Kruskals algorithm is a feasible method for query optimization.

Stableness in large join query optimization

In relational database model, the use of exhaustive search methods in the large join query optimization is prohibitive because of the exponential increase of search space. An alternative widely discussed is the use of randomized search techniques. Several previous researches have been showed that the use of randomized sampling in query optimization permits to find, in average, near optimal plans in polynomial time. However, due to their random components, the quality of yielded plans for the same query may vary a lot, making the response time of a submitted query unpredictable. On the other hand, the use of heuristic optimization may increase stability of response time. This characteristic is essential in environments where response time must be predicted. In this paper, we will compare a randomized algorithm and a heuristic algorithm applied to large join query optimization. We used an open source DBMS as experimental framework and we compared the quality and stability of these algorithms.

Alternância entre competição e colaboração para promover o aprendizado por meio de heurísticas de jogos

Resumo: Em busca de novos metodos que auxiliem no aprendizado de portadores de necessidades especiais, um jogo utilizando a tecnologia de agentes virtuais foi criado, atraves da linguagem brasileira de sinais, LIBRAS, o modelo grafico repassa toda informacao necessaria a manipulacao do jogo didatico, despertando no aluno a autonomia e o interesse pelo conteudo abordado. Abstract: Looking for new methods to help learning, a game using the technology of virtual agent was created, a graphic model using the LIBRAS language to transmit all information that is necessary to the student to manipulate the game, increasing his will of learning and self improving.Resumo: Tem sido ampla e intensamente divulgado e aplicado o uso do computador para fins de aprendizagem em diversos dominios. Partindo dessa perspectiva, deu-se inicio a um trabalho na Casa de Saude Paulo de Tarso, o qual tem como objetivo primordial auxiliar na melhoria da coordenacao motora dos pacientes da referida Instituicao e, por consequencia, aumentar a auto-estima, contribuir com o aprendizado, dentre outros. Abstract: The use of the computer has been wide and intensely divulged and applied in the learning process in diverse dominions. In agreement with this perspective, it was started a work at the Health Institution “Paulo de Tarso”, which has as its major goal to assistant in the improvement of the patients motor coordination in the above-mentioned Institution and, by consequence, to augment the self-esteem, to contribute to apprenticeship, among others.Resumo: A Universidade Federal de Mato Grosso (UFMT) - Campus de Rondonopolis, atraves de alguns estudantes, do 4o ano do curso de Licenciatura em Informatica, em pleno exercicio de seu estagio supervisionado, firmou uma parceria com a EEMOP (Escola Estadual Major Otavio Pitaluga) em maio de 2005 para que juntos realizassem um trabalho, onde os estagiarios estariam auxiliando a utilizacao da Internet durante o processo de ensino-aprendizagem na referida escola. Abstract: Mato Grosso’s Federal University (UFMT) Rondonopolis’s Campus, through some students, of the fourth year of the Graduation Course of Degreee in Informatics, in full exercise of their supervised probation period, established a partnership with EEMOP (Major Otavio Pitaluga State School) in may of 2005 so that together they could accomplish a work, where the trainees would be assisting the use of Internet during the teaching- learning process at the above-mentioned school.Resumo: A educacao a distância (EAD) se apresenta no seculo XXI como um novo espaco de trabalho docente, trazendo mudancas nos papeis tradicionais, requerendo um preparo especial do professor. Para verificar se as IES que oferecem EAD formam seus docentes para ensinar a distância e como fazem este trabalho, foi feita uma pesquisa atraves de questionarios enviados por e- mail para 15 IES de Santa Catarina. O presente artigo discute os resultados encontrados que mostraram que as IES catarinenses nao apenas se preocupam com a producao de materiais didaticos, mas estao criando estruturas de apoio para formar seus professores para ensinar a distância. Abstract: Distance education (DE) is presenting, in the 21st century, a new challenge for teachers, asking for a change in their traditional roles, and requiring them to be specially trained for it. In order to find out if the Higher Education Institutions offering DE are training their teachers to work at a distance and how this preparation has been done, a research was conducted in the state of Santa Catarina, Brazil, using a questionnaire, sent by e-mail to 15 institutions. This article presents and discuss the results, showing that the Higher Education Institutions offering DE are not concerned only about the production of the course materials but are, also, creating support structures to prepare their professionals to teach at a distance.Resumo: Este artigo apresenta resultados iniciais de uma pesquisa visando diagnosticar a situacao da informatica educativa no municipio de Belem(PA). Esse diagnostico foi feito tendo-se como referencia um conjunto de criterios propostos para o planejamento e a avaliacao de experiencias em informatica educativa. Entre os resultados apresentados pode-se destacar o contraste entre a rede publica e a privada e o baixo investimento na formacao docente para essa atividade. Abstract: This paper presents the initial results of a diagnostic of the current state of educative informatics in Belem, Para. To perform such analysis, we used a set of criteria that aimed to evaluate the different educative informatics experiences reported. Among the results it is possible to notice clearly the contrast between the public and private school system and the low investment in the teaching personnel.

Extending OAI-PMH over structured P2P networks for digital preservation

Open archives initiative (OAI) allows both libraries and museums create and share their own low-cost digital libraries (DL). OAI DL are based on OAI-PMH protocol which, although is consolidated as a pattern for disseminating metadata, does not rely on either digital preservation and availability of content, essential requirements in this type of system. Building new mechanisms that guarantee improvements, at no or low cost increases, becomes a great challenge. This article proposes a distributed archiving system based on a P2P network, that allows OAI-based libraries to replicate digital objects to ensure their reliability and availability. The proposed system keeps and extends the current OAI-PMH protocol characteristics and is designed as a set of OAI repositories, where each repository has an independent fail probability assigned to it. Items are inserted with a reliability that is satisfied by replicating them in subsets of repositories. Communication between the nodes (repositories) of the network is organized in a distributed hash table and multiple hash functions are used to select repositories that keep the replicas of each stored item. The OAI characteristics combined with a structured P2P digital preservation system allow the construction of a reliable and totally distributed digital library. The archiving system has been evaluated through experiments in a real environment and the OAI-PMH extension validated by the implementation of a proof-of-principle prototype.

Acquiring Expertise in Medical Radiology through Long-Term Interactions

This paper describes how cognitive and computational concepts can be applied to build interface and learner models for long-term tutorial interactions in medical radiology. Key human-to-human tutorial dialogue factors that typically occur in the different stages of skill acquisition are captured through an empirical study. The results of the study are detailed and linked to the design of RUI, an intelligent tutoring system for multiple domains of radiological expertise. A brief discussion and future research directions offer a comparative view of the method and tools.

Long-term digital archiving based on selection of repositories over P2P networks

The importance of digital information is constantly increasing in the last years. Such information often needs to be preserved for a long-term and this is the responsibility of digital archiving systems. This paper proposes a reliable replication model of immutable digital content to be used in long-term archiving systems. The archiving system is modeled as a set of storage repositories where each repository has an independent fail probability assigned to it. Items are inserted with a reliability that is satisfied by replicating them in subsets of repositories. Through simulation, we evaluated three different proposed strategies to create replicas. It is also proposed a completely distributed archiving system using this model over a structured peer-to-peer (P2P) network. The communication between the nodes (repositories) of the network is organized in a distributed hash table and multiple hash functions are used to select repositories that will keep the replicas of each stored item. The system is evaluated through experiments in a real environment. The proposed model and the algorithms, combined with the structured P2P scalability made possible the construction of a reliable and totally distributed digital archiving system.

Distributed Benchmarking of Relational Database Systems

Todays DBMS are constantly upon large-scale workloads (e.g., internet) and require a reliable tool to benchmark them upon a similar workload. Usually, benchmarking tools simulate a multi-user workload within a single machine. However, this avoids large-scale benchmarking and also introduces deviations in the result. In this paper, we present a solution for benchmarking DBMS in a fully distributed manner. The solution is based on the TPC-C specification and aims to simulate large-scale workloads. We validate our solution through implementation and experimentation on three open-source DBMS. Through experimentation, we analyze the behavior of all systems and show how our solution is able to scale up the benchmark.

Authoring Adaptive Tutoring Systems for Complex Visual Skills

In the world of Intelligent Tutoring Systems research, the connection between learner models and interaction models has been largely ignored. Similarly, previous works have not accounted for the dynamic representation of interface contents based on the underlying pedagogic directives. The paper describes an approach to the authoring of training contents aimed at intermediate-level learners of medical Radiology. It is argued that, in certain dialogues designed for supporting visual diagnosis, it is worthwhile employing domain-general teaching mechanisms and reuse them in various domain-specific situations. An empirical study has been carried out with a corpus of human-to-human tutorial dialogues to identify the component features of expertise in medical Radiology. The results of the study form the basis for implementing interface and learner models that guide long-term tutorial interactions through an intelligent shell called RUI. Conclusions and future research directions are also described briefly.

A user-interface environment solution for an online educational Chess server

This paper describes an interface and interaction environment for a public online Chess server, on the web, as an educational tool. The main purpose of the environment is to improve Chess teaching in Brazilian public schools. The vast majority of such Chess online servers consider and take for granted that users are specialists rather than learners. The solution described in this paper is inserted in an education environment, aiming at providing users with direct access to the contextually significant actions by means of strategic and operational help.

Visualização de táticas para apoiar a aquisição de habilidades em jogos educacionais

Resumo: A pesquisa teve como objetivo verificar as relacoes sociais entre os individuos, numa disciplina presencial, quando suportadas por um ambiente virtual. Foi aplicado um questionario semi-estruturado com 17 alunos de uma disciplina de um curso de Mestrado. A analise constatou indicios de uma comunidade presente nas trocas existentes entre os alunos da disciplina. Abstract: The research aimed to investigate social relationships between students and teahcer in a classroom setting when using a Virtual Learning Environment. A survey was conducted with 17 students from a graduate course. The results indicate traces of a community in the exchange between students.Resumo: Este artigo apresenta os resultados do curso “Introducao ao Estudo da Dislexia” desenvolvido na plataforma MIRANTE - Midia Interativa com Recursos de Acessibilidade, que se destina a capacitacao de professores para trabalharem com alunos dislexicos. Analisa o desempenho dos cursistas, nao so na apropriacao do conteudo do curso, mas tambem no ambiente virtual interativo que permite a flexibilizacao do ensino e a promocao de processos individuais de aprendizagem. Abstract: This article describes the first module of a teachers’s capacitation courser available in the long-distance education enviroment MIRANTE - Interactive Media with the Accessibility Resources of NTE. Its subject is the Dyslexia, which represents, at the current moment, a serious problem a mong student. Education professionals are, each time, more aware of it. To capacitate long-distance teachers, discussing the characteristics of Dyslexia end pointing out the resources for the inclusion of those students and the development of methods and technologies, which may help students with learning problem, is the aim of this course.Resumo: Este artigo resumido descreve a experiencia do Curso “A Literatura Infantil e o Livro Eletronico” desenvolvido no Nucleo de Tecnologia Educacional de Sao Pedro da Aldeia – NTE RJ 10 com alunos do Curso de Formacao de Professores. Abstract: This summarized article describes the experience of the Course “The Infantile Literature and the Eletronic Book” developed into the Nucleo de Tecnologia Educacional de Sao Pedro da Aldeia – NTE RJ 10 with students of the Teacher Training Course.Resumo: Este artigo aborda o ensino da Arte atraves do trabalho com projetos e utilizacao do ambiente colaborativo SOCRATES. A pesquisa foi realizada numa escola da rede municipal de ensino de Fortaleza, com alunos do 7o ano. Os dados apresentados compoem os foruns de discussao realizados durante o projeto A Arte pela Arte. Dentre os resultados, enfoca-se a interacao constante, a aprendizagem colaborativa e o uso intensivo dos recursos tecnologicos. Tais dados indicam que trabalhar com projetos tendo o SOCRATES como suporte constitui-se em alternativa viavel para a dinamizacao da Arte como disciplina dos curriculos. Abstract: The study investigated a project-based approach for art teaching with support of a virtual environment called SOCRATES. The research was conducted in a public school in Fortaleza with 7th grade students. Data was composed of messages from the SOCRATES forum during a Project called “Art by Art”. Results indicate the presence of constant students’ interaction, collaborative learning and intensive use of technological resources. Such data indicate that the project based approach, supported by SOCRATES, is a viable alternative to promote Arts as a discipline in school curriculum.