Tecnologias GRID para bibliotecas digitais

Mestrado em Engenharia Electrónica e TelecomunicaçõesEste trabalho teve como objectivo, numa primeira fase fazer um estudo das tecnologias Grid existentes, essencialmente para a plataforma Windows. Esse estudo teve como propósito, a escolha de uma framework para sistemas Grid, a qual foi feita tendo em consideração as características, documentação disponível e desempenho das Frameworks analisadas. Esta fase do projecto está exposta na primeira parte da dissertação. Onde se explica pormenorizadamente o conceito de Grid, e algumas das tecnologias que o implementam. Numa segunda fase, e a partir da framework para Grid escolhida, desenvolveu-se um software com o objectivo de converter as páginas de um documento PDF em imagens do tipo PNG. Esta conversão é feita no âmbito da biblioteca digital SInBAD, onde as páginas dos documentos são apresentadas sob a forma de imagens. A conversão em causa é demorada e requer grandes quantidades de processamento, ao usar a tecnologia GRID para esta conversão, pretendeu-se tornar este processo muito mais rápido. ABSTRACT: The objective of this work was, in a first stage, to study some of the existent GRID technologies, mainly the ones developed for windows platforms. The purpose of this study was to select a Grid framework, the choice was made based on the framework characteristics, available documentation, and it´s performance. This first stage is described on the first part of this thesis. Where is included a detailed explanation of the GRID concept, and is described some of the GRID technologies. In a second stage of the work, has been developed a software for the selected GRID framework, which converts the pages of a PDF document to PNG images. This conversion is made for the digital library SInBAD, where the documents pages are presented as images. The conversion of PDF pages to PNG images is a slow process that requires a great amount of digital processing, the use of GRID technology for this process has the aim of make it quicker

A service-oriented Grid environment with on-demand QoS support

Grid Computing entstand aus der Vision für eine neuartige Recheninfrastruktur, welche darauf abzielt, Rechenkapazität so einfach wie Elektrizität im Stromnetz (power grid) verfügbar zu machen. Der entsprechende Zugriff auf global verteilte Rechenressourcen versetzt Forscher rund um den Globus in die Lage, neuartige Herausforderungen aus Wissenschaft und Technik in beispiellosem Ausmaß in Angriff zu nehmen. Die rasanten Entwicklungen im Grid Computing begünstigten auch Standardisierungsprozesse in Richtung Harmonisierung durch Service-orientierte Architekturen und die Anwendung kommerzieller Web Services Technologien. In diesem Kontext ist auch die Sicherung von Qualität bzw. entsprechende Vereinbarungen über die Qualität eines Services (QoS) wichtig, da diese vor allem für komplexe Anwendungen aus sensitiven Bereichen, wie der Medizin, unumgänglich sind. Diese Dissertation versucht zur Entwicklung im Grid Computing beizutragen, indem eine Grid Umgebung mit Unterstützung für QoS vorgestellt wird. Die vorgeschlagene Grid Umgebung beinhaltet eine sichere Service-orientierte Infrastruktur, welche auf Web Services Technologien basiert, sowie bedarfsorientiert und automatisiert HPC Anwendungen als Grid Services bereitstellen kann. Die Grid Umgebung zielt auf eine kommerzielle Nutzung ab und unterstützt ein durch den Benutzer initiiertes, fallweises und dynamisches Verhandeln von Serviceverträgen (SLAs). Das Design der QoS Unterstützung ist generisch, jedoch berücksichtigt die Implementierung besonders die Anforderungen von rechenintensiven und zeitkritischen parallelen Anwendungen, bzw. Garantien f¨ur deren Ausführungszeit und Preis. Daher ist die QoS Unterstützung auf Reservierung, anwendungsspezifische Abschätzung und Preisfestsetzung von Ressourcen angewiesen. Eine entsprechende Evaluation demonstriert die Möglichkeiten und das rationale Verhalten der QoS Infrastruktur. Die Grid Infrastruktur und insbesondere die QoS Unterstützung wurde in Forschungs- und Entwicklungsprojekten der EU eingesetzt, welche verschiedene Anwendungen aus dem medizinischen und bio-medizinischen Bereich als Services zur Verfügung stellen. Die EU Projekte GEMSS und Aneurist befassen sich mit fortschrittlichen HPC Anwendungen und global verteilten Daten aus dem Gesundheitsbereich, welche durch Virtualisierungstechniken als Services angeboten werden. Die Benutzung von Gridtechnologie als Basistechnologie im Gesundheitswesen ermöglicht Forschern und Ärzten die Nutzung von Grid Services in deren Arbeitsumfeld, welche letzten Endes zu einer Verbesserung der medizinischen Versorgung führt.Grid computing emerged as a vision for a new computing infrastructure that aims to make computing resources available as easily as electric power through the power grid. Enabling seamless access to globally distributed IT resources allows dispersed users to tackle large-scale problems in science and engineering in unprecedented ways. The rapid development of Grid computing also encouraged standardization, which led to the adoption of a service-oriented paradigm and an increasing use of commercial Web services technologies. Along these lines, service-level agreements and Quality of Service are essential characteristics of the Grid and specifically mandatory for Grid-enabling complex applications from certain domains such as the health sector. This PhD thesis aims to contribute to the development of Grid technologies by proposing a Grid environment with support for Quality of Service. The proposed environment comprises a secure service-oriented Grid infrastructure based on standard Web services technologies which enables the on-demand provision of native HPC applications as Grid services in an automated way and subject to user-defined QoS constraints. The Grid environment adopts a business-oriented approach and supports a client-driven dynamic negotiation of service-level agreements on a case-by-case basis. Although the design of the QoS support is generic, the implementation emphasizes the specific requirements of compute-intensive and time-critical parallel applications, which necessitate on-demand QoS guarantees such as execution time limits and price constraints. Therefore, the QoS infrastructure relies on advance resource reservation, application-specific resource capacity estimation, and resource pricing. An experimental evaluation demonstrates the capabilities and rational behavior of the QoS infrastructure. The presented Grid infrastructure and in particular the QoS support has been successfully applied and demonstrated in EU projects for various applications from the medical and bio-medical domains. The EU projects GEMSS and Aneurist are concerned with advanced e-health applications and globally distributed data sources, which are virtualized by Grid services. Using Grid technology as enabling technology in the health domain allows medical practitioners and researchers to utilize Grid services in their clinical environment which ultimately results in improved healthcare

Architectural Foundations

State management has always been an underlying issue for large-scale distributed systems, but only recently has it been brought to the forefront of Grid computing with the introduction of the Web Services Resource Framework (WSRF) and its companion, WS-Notification. WSRF advocates standardized approaches for client exposure to and potential manipulation of stateful services for Grid computing; however, these arguments and their long-term implications have been difficult to assess without a concrete implementation of the WSRF specifications. This paper describes the architectural foundations of WSRF.NET, which is an implementation of the full set of specifications for WSRF and WS-Notification on the Microsoft.NET Framework. To our knowledge, the observations and lessons learned from the design and implementation of WSRF.NET provide the first evaluation of the WSRF approach. A concrete example of the design, implementation, and deployment of a WSRF-compliant service and its accompanying WSRF-compliant client are used to guide the discussion. While the potential of WSRF and WS-Notification remains strong, initial observations are that there are many challenges that remain to be solved, most notably the implied programming model derived from the specifications, particularly the complexity of service side and client code and the complexity of WS-Notification