896 resultados para Relational database


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With the recent explosion in the complexity and amount of digital multimedia data, there has been a huge impact on the operations of various organizations in distinct areas, such as government services, education, medical care, business, entertainment, etc. To satisfy the growing demand of multimedia data management systems, an integrated framework called DIMUSE is proposed and deployed for distributed multimedia applications to offer a full scope of multimedia related tools and provide appealing experiences for the users. This research mainly focuses on video database modeling and retrieval by addressing a set of core challenges. First, a comprehensive multimedia database modeling mechanism called Hierarchical Markov Model Mediator (HMMM) is proposed to model high dimensional media data including video objects, low-level visual/audio features, as well as historical access patterns and frequencies. The associated retrieval and ranking algorithms are designed to support not only the general queries, but also the complicated temporal event pattern queries. Second, system training and learning methodologies are incorporated such that user interests are mined efficiently to improve the retrieval performance. Third, video clustering techniques are proposed to continuously increase the searching speed and accuracy by architecting a more efficient multimedia database structure. A distributed video management and retrieval system is designed and implemented to demonstrate the overall performance. The proposed approach is further customized for a mobile-based video retrieval system to solve the perception subjectivity issue by considering individual user's profile. Moreover, to deal with security and privacy issues and concerns in distributed multimedia applications, DIMUSE also incorporates a practical framework called SMARXO, which supports multilevel multimedia security control. SMARXO efficiently combines role-based access control (RBAC), XML and object-relational database management system (ORDBMS) to achieve the target of proficient security control. A distributed multimedia management system named DMMManager (Distributed MultiMedia Manager) is developed with the proposed framework DEMUR; to support multimedia capturing, analysis, retrieval, authoring and presentation in one single framework.

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Over the past five years, XML has been embraced by both the research and industrial community due to its promising prospects as a new data representation and exchange format on the Internet. The widespread popularity of XML creates an increasing need to store XML data in persistent storage systems and to enable sophisticated XML queries over the data. The currently available approaches to addressing the XML storage and retrieval issue have the limitations of either being not mature enough (e.g. native approaches) or causing inflexibility, a lot of fragmentation and excessive join operations (e.g. non-native approaches such as the relational database approach). ^ In this dissertation, I studied the issue of storing and retrieving XML data using the Semantic Binary Object-Oriented Database System (Sem-ODB) to leverage the advanced Sem-ODB technology with the emerging XML data model. First, a meta-schema based approach was implemented to address the data model mismatch issue that is inherent in the non-native approaches. The meta-schema based approach captures the meta-data of both Document Type Definitions (DTDs) and Sem-ODB Semantic Schemas, thus enables a dynamic and flexible mapping scheme. Second, a formal framework was presented to ensure precise and concise mappings. In this framework, both schemas and the conversions between them are formally defined and described. Third, after major features of an XML query language, XQuery, were analyzed, a high-level XQuery to Semantic SQL (Sem-SQL) query translation scheme was described. This translation scheme takes advantage of the navigation-oriented query paradigm of the Sem-SQL, thus avoids the excessive join problem of relational approaches. Finally, the modeling capability of the Semantic Binary Object-Oriented Data Model (Sem-ODM) was explored from the perspective of conceptually modeling an XML Schema using a Semantic Schema. ^ It was revealed that the advanced features of the Sem-ODB, such as multi-valued attributes, surrogates, the navigation-oriented query paradigm, among others, are indeed beneficial in coping with the XML storage and retrieval issue using a non-XML approach. Furthermore, extensions to the Sem-ODB to make it work more effectively with XML data were also proposed. ^

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Component-based Software Engineering (CBSE) and Service-Oriented Architecture (SOA) became popular ways to develop software over the last years. During the life-cycle of a software system, several components and services can be developed, evolved and replaced. In production environments, the replacement of core components, such as databases, is often a risky and delicate operation, where several factors and stakeholders should be considered. Service Level Agreement (SLA), according to ITILv3’s official glossary, is “an agreement between an IT service provider and a customer. The agreement consists on a set of measurable constraints that a service provider must guarantee to its customers.”. In practical terms, SLA is a document that a service provider delivers to its consumers with minimum quality of service (QoS) metrics.This work is intended to assesses and improve the use of SLAs to guide the transitioning process of databases on production environments. In particular, in this work we propose SLA-Based Guidelines/Process to support migrations from a relational database management system (RDBMS) to a NoSQL one. Our study is validated by case studies.

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Repeat photography is an efficient, effective and useful method to identify trends of changes in the landscapes. It was used to illustrate long-term changes occurring in the landscapes. In the Northeast of Portugal, landscapes changes is currently driven mostly by agriculture abandonment and agriculture and energy policy. However, there is a need to monitoring changes in the region using a multitemporal and multiscale approach. This project aimed to establish an online repository of oblique digital photography from the region to be used to register the condition of the landscape as recorded in historical and contemporary photography over time as well as to support qualitative and quantitative assessment of change in the landscape using repeat photography techniques and methods. It involved the development of a relational database and a series of web-based services using PHP: Hypertext Preprocessor language, and the development of an interface, with Joomla, of pictures uploading and downloading by users. The repository will make possible to upload, store, search by location, theme, or date, display, and download pictures for Northeastern Portugal. The website service is devoted to help researchers to obtain quickly the photographs needed to apply RP through a developed search engine. It can be accessed at: http://esa.ipb.pt/digitalandscape/.

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This paper describes the development of a relational database and a tool for viewing MODIS NDVI temporal profile, using data from MOD09Q1 product, specifically the surface bidirectional reflectance factor relative to the RED and NIR wavelength, mosaic of 8-day temporal composition, and the quality band, in sugarcane fields in the state of São Paulo, for analysis of the late stubble-cane maturation. From sugarcane farms were obtained the historical data about yield, soil, variety, location of the each pixel for each subregion monitored. All data were integrated in a database developed in PostgreSQL. The tool was implemented using Java language and allowed a fast and automatic way of analyzing sugarcane phenological patterns. It concluded that the MODIS NDVI temporal profile using data from MOD09Q1 product is able to subsidize the monitoring of phenological changes in the sugarcane.

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This paper examines the effects of information request ambiguity and construct incongruence on end user's ability to develop SQL queries with an interactive relational database query language. In this experiment, ambiguity in information requests adversely affected accuracy and efficiency. Incongruities among the information request, the query syntax, and the data representation adversely affected accuracy, efficiency, and confidence. The results for ambiguity suggest that organizations might elicit better query development if end users were sensitized to the nature of ambiguities that could arise in their business contexts. End users could translate natural language queries into pseudo-SQL that could be examined for precision before the queries were developed. The results for incongruence suggest that better query development might ensue if semantic distances could be reduced by giving users data representations and database views that maximize construct congruence for the kinds of queries in typical domains. (C) 2001 Elsevier Science B.V. All rights reserved.

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With the proliferation of relational database programs for PC's and other platforms, many business end-users are creating, maintaining, and querying their own databases. More importantly, business end-users use the output of these queries as the basis for operational, tactical, and strategic decisions. Inaccurate data reduce the expected quality of these decisions. Implementing various input validation controls, including higher levels of normalisation, can reduce the number of data anomalies entering the databases. Even in well-maintained databases, however, data anomalies will still accumulate. To improve the quality of data, databases can be queried periodically to locate and correct anomalies. This paper reports the results of two experiments that investigated the effects of different data structures on business end-users' abilities to detect data anomalies in a relational database. The results demonstrate that both unnormalised and higher levels of normalisation lower the effectiveness and efficiency of queries relative to the first normal form. First normal form databases appear to provide the most effective and efficient data structure for business end-users formulating queries to detect data anomalies.

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The changes introduced into the European Higher Education Area (EHEA) by the Bologna Process, together with renewed pedagogical and methodological practices, have created a new teaching-learning paradigm: Student-Centred Learning. In addition, the last few years have been characterized by the application of Information Technologies, especially the Semantic Web, not only to the teaching-learning process, but also to administrative processes within learning institutions. On one hand, the aim of this study was to present a model for identifying and classifying Competencies and Learning Outcomes and, on the other hand, the computer applications of the information management model were developed, namely a relational Database and an Ontology.

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Mestrado em Engenharia Informática - Área de Especialização em Tecnologias do Conhecimento e Decisão

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Na atualidade, existe uma quantidade de dados criados diariamente que ultrapassam em muito as mais otimistas espectativas estabelecidas na década anterior. Estes dados têm origens bastante diversas e apresentam-se sobre várias formas. Este novo conceito que dá pelo nome de Big Data está a colocar novos e rebuscados desafios ao seu armazenamento, tratamento e manipulação. Os tradicionais sistemas de armazenamento não se apresentam como a solução indicada para este problema. Estes desafios são alguns dos mais analisados e dissertados temas informáticos do momento. Várias tecnologias têm emergido com esta nova era, das quais se salienta um novo paradigma de armazenamento, o movimento NoSQL. Esta nova filosofia de armazenamento visa responder às necessidades de armazenamento e processamento destes volumosos e heterogéneos dados. Os armazéns de dados são um dos componentes mais importantes do âmbito Business Intelligence e são, maioritariamente, utilizados como uma ferramenta de apoio aos processos de tomada decisão, levados a cabo no dia-a-dia de uma organização. A sua componente histórica implica que grandes volumes de dados sejam armazenados, tratados e analisados tendo por base os seus repositórios. Algumas organizações começam a ter problemas para gerir e armazenar estes grandes volumes de informação. Esse facto deve-se, em grande parte, à estrutura de armazenamento que lhes serve de base. Os sistemas de gestão de bases de dados relacionais são, há algumas décadas, considerados como o método primordial de armazenamento de informação num armazém de dados. De facto, estes sistemas começam a não se mostrar capazes de armazenar e gerir os dados operacionais das organizações, sendo consequentemente cada vez menos recomendada a sua utilização em armazéns de dados. É intrinsecamente interessante o pensamento de que as bases de dados relacionais começam a perder a luta contra o volume de dados, numa altura em que um novo paradigma de armazenamento surge, exatamente com o intuito de dominar o grande volume inerente aos dados Big Data. Ainda é mais interessante o pensamento de que, possivelmente, estes novos sistemas NoSQL podem trazer vantagens para o mundo dos armazéns de dados. Assim, neste trabalho de mestrado, irá ser estudada a viabilidade e as implicações da adoção de bases de dados NoSQL, no contexto de armazéns de dados, em comparação com a abordagem tradicional, implementada sobre sistemas relacionais. Para alcançar esta tarefa, vários estudos foram operados tendo por base o sistema relacional SQL Server 2014 e os sistemas NoSQL, MongoDB e Cassandra. Várias etapas do processo de desenho e implementação de um armazém de dados foram comparadas entre os três sistemas, sendo que três armazéns de dados distintos foram criados tendo por base cada um dos sistemas. Toda a investigação realizada neste trabalho culmina no confronto da performance de consultas, realizadas nos três sistemas.

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Com o advento da invenção do modelo relacional em 1970 por E.F.Codd, a forma como a informação era gerida numa base de dados foi totalmente revolucionada. Migrou‐se de sistemas hierárquicos baseados em ficheiros para uma base de dados relacional com tabelas relações e registos que simplificou em muito a gestão da informação e levou muitas empresas a adotarem este modelo. O que E.F.Codd não previu foi o facto de que cada vez mais a informação que uma base de dados teria de armazenar fosse de proporções gigantescas, nem que as solicitações às bases de dados fossem da mesma ordem. Tudo isto veio a acontecer com a difusão da internet que veio ligar todas as pessoas de qualquer parte do mundo que tivessem um computador. Com o número de adesões à internet a crescer, o número de sites que nela eram criados também cresceu (e ainda cresce exponencialmente). Os motores de busca que antigamente indexavam alguns sites por dia, atualmente indexam uns milhões de sites por segundo e, mais recentemente as redes sociais também estão a lidar com quantidades gigantescas de informação. Tanto os motores de busca como as redes sociais chegaram à conclusão que uma base de dados relacional não chega para gerir a enorme quantidade de informação que ambos produzem e como tal, foi necessário encontrar uma solução. Essa solução é NoSQL e é o assunto que esta tese vai tratar. O presente documento visa definir e apresentar o problema que as bases de dados relacionais têm quando lidam com grandes volumes de dados, introduzir os limites do modelo relacional que só até há bem pouco tempo começaram a ser evidenciados com o surgimento de movimentos, como o BigData, com o crescente número de sites que surgem por dia e com o elevado número de utilizadores das redes sociais. Será também ilustrada a solução adotada até ao momento pelos grandes consumidores de dados de elevado volume, como o Google e o Facebook, enunciando as suas características vantagens, desvantagens e os demais conceitos ligados ao modelo NoSQL. A presente tese tenciona ainda demonstrar que o modelo NoSQL é uma realidade usada em algumas empresas e quais as principias mudanças a nível programático e as boas práticas delas resultantes que o modelo NoSQL traz. Por fim esta tese termina com a explicação de que NoSQL é uma forma de implementar a persistência de uma aplicação que se inclui no novo modelo de persistência da informação.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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The MAP-i doctoral program of the Universities of Minho, Aveiro and Porto

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Desenvolupar una aplicació web en Java j2ee, i més concretament un cercador de formacions.

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Bases de dades i magatzems de dades: disseny i implementació d'una base de dades relacional per al manteniment d'aparells d'una empresa.