1,325 research outputs found
Grid-enabled Workflows for Industrial Product Design
This paper presents a generic approach for developing and using Grid-based workflow technology for enabling cross-organizational engineering applications. Using industrial product design examples from the automotive and aerospace industries we highlight the main requirements and challenges addressed by our approach and describe how it can be used for enabling interoperability between heterogeneous workflow engines
A Review of Platforms for the Development of Agent Systems
Agent-based computing is an active field of research with the goal of
building autonomous software of hardware entities. This task is often
facilitated by the use of dedicated, specialized frameworks. For almost thirty
years, many such agent platforms have been developed. Meanwhile, some of them
have been abandoned, others continue their development and new platforms are
released. This paper presents a up-to-date review of the existing agent
platforms and also a historical perspective of this domain. It aims to serve as
a reference point for people interested in developing agent systems. This work
details the main characteristics of the included agent platforms, together with
links to specific projects where they have been used. It distinguishes between
the active platforms and those no longer under development or with unclear
status. It also classifies the agent platforms as general purpose ones, free or
commercial, and specialized ones, which can be used for particular types of
applications.Comment: 40 pages, 2 figures, 9 tables, 83 reference
Distributed Web Service Coordination for Collaboration Applications and Biological Workflows
In this dissertation work, we have investigated the main research thrust of decentralized coordination of workflows over web services. To address distributed workflow coordination, first we have developed “Web Coordination Bonds” as a capable set of dependency modeling primitives that enable each web service to manage its own dependencies. Web bond primitives are as powerful as extended Petri nets and have sufficient modeling and expressive capabilities to model workflow dependencies. We have designed and prototyped our “Web Service Coordination Management Middleware” (WSCMM) system that enhances current web services infrastructure to accommodate web bond enabled web services. Finally, based on core concepts of web coordination bonds and WSCMM, we have developed the “BondFlow” system that allows easy configuration distributed coordination of workflows. The footprint of the BonFlow runtime is 24KB and the additional third party software packages, SOAP client and XML parser, account for 115KB
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A distributed analysis and monitoring framework for the compact Muon solenoid experiment and a pedestrian simulation
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The design of a parallel and distributed computing system is a very complicated task. It requires a detailed understanding of the design issues and of the theoretical and practical aspects of their solutions. Firstly, this thesis discusses in detail the major concepts and components required to make parallel and distributed computing a reality. A multithreaded and distributed framework capable of analysing the simulation data produced by a pedestrian simulation software was developed. Secondly, this thesis discusses the origins and fundamentals of Grid computing and the motivations for its use in High Energy Physics. Access to the data produced by the Large Hadron Collider (LHC) has to be provided for more than five thousand scientists all over the world. Users who run analysis jobs on the Grid do not necessarily have expertise in Grid computing. Simple, userfriendly and reliable monitoring of the analysis jobs is one of the key components of the operations of the distributed analysis; reliable monitoring is one of the crucial components of the Worldwide LHC Computing Grid for providing the functionality and performance that is required by the LHC experiments. The CMS Dashboard Task Monitoring and the CMS Dashboard Job Summary monitoring applications were developed to serve the needs of the CMS community
The distributed ASCI supercomputer project
The Distributed ASCI Supercomputer (DAS) is a homogeneous wide-area distributed system consisting of four cluster computers at different locations. DAS has been used for research on communication software, parallel languages and programming systems, schedulers, parallel applications, and distributed applications. The paper gives a preview of the most interesting research results obtained so far in the DAS project
State-of-the-art on evolution and reactivity
This report starts by, in Chapter 1, outlining aspects of querying and updating resources on
the Web and on the Semantic Web, including the development of query and update languages
to be carried out within the Rewerse project.
From this outline, it becomes clear that several existing research areas and topics are of
interest for this work in Rewerse. In the remainder of this report we further present state of
the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give
an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs;
in Chapter 4 event-condition-action rules, both in the context of active database systems and
in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks
VISOR: virtual machine images management service for cloud infarestructures
Cloud Computing is a relatively novel paradigm that aims to fulfill the computing as utility dream. It has appeared to bring the possibility of providing computing resources (such as servers, storage and networks) as a service and on demand, making them accessible through common Internet protocols. Through cloud offers, users only need to pay for the amount of resources they
need and for the time they use them. Virtualization is the clouds key technology, acting upon virtual machine images to deliver fully functional virtual machine instances. Therefore, virtual machine images play an important role in Cloud Computing and their efficient management becomes a key concern that should be carefully addressed. To tackle this requirement, most cloud offers provide their own image repository, where images are stored and retrieved from, in order to instantiate new virtual machines. However, the rise of Cloud Computing has brought
new problems in managing large collections of images.
Existing image repositories are not able to efficiently manage, store and catalogue virtual machine images from other clouds through the same centralized service repository. This becomes especially important when considering the management of multiple heterogeneous cloud offers. In fact, despite the hype around Cloud Computing, there are still existing barriers to its widespread adoption. Among them, clouds interoperability is one of the most notable issues.
Interoperability limitations arise from the fact that current cloud offers provide proprietary interfaces, and their services are tied to their own requirements. Therefore, when dealing with multiple heterogeneous clouds, users face hard to manage integration and compatibility issues.
The management and delivery of virtual machine images across different clouds is an example of such interoperability constraints.
This dissertation presents VISOR, a cloud agnostic virtual machine images management service and repository. Our work towards VISOR aims to provide a service not designed to fit in a specific cloud offer but rather to overreach sharing and interoperability limitations among different clouds. With VISOR, the management of clouds interoperability can be seamlessly abstracted
from the underlying procedures details. In this way, it aims to provide users with the
ability to manage and expose virtual machine images across heterogeneous clouds, throughout the same generic and centralized repository and management service. VISOR is an open source software with a community-driven development process, thus it can be freely customized and further improved by everyone. The conducted tests to evaluate its performance and resources
usage rate have shown VISOR as a stable and high performance service, even when compared
with other services already in production. Lastly, placing clouds as the main target audience is not a limitation for other use cases. In fact, virtualization and virtual machine images are not exclusively linked to cloud environments. Therefore and given the service agnostic design concerns, it is possible to adapt it to other usage scenarios as well.A Computação em Nuvem (”Cloud Computing”) é um paradigma relativamente novo que visa
cumprir o sonho de fornecer a computação como um serviço. O mesmo surgiu para possibilitar o
fornecimento de recursos de computação (servidores, armazenamento e redes) como um serviço
de acordo com as necessidades dos utilizadores, tornando-os acessĂveis atravĂ©s de protocolos de
Internet comuns. Através das ofertas de ”cloud”, os utilizadores apenas pagam pela quantidade
de recursos que precisam e pelo tempo que os usam. A virtualização é a tecnologia chave
das ”clouds”, atuando sobre imagens de máquinas virtuais de forma a gerar máquinas virtuais
totalmente funcionais. Sendo assim, as imagens de máquinas virtuais desempenham um papel
fundamental no ”Cloud Computing” e a sua gestão eficiente torna-se um requisito que deve ser
cuidadosamente analisado. Para fazer face a tal necessidade, a maioria das ofertas de ”cloud”
fornece o seu prĂłprio repositĂłrio de imagens, onde as mesmas sĂŁo armazenadas e de onde
são copiadas a fim de criar novas máquinas virtuais. Contudo, com o crescimento do ”Cloud
Computing” surgiram novos problemas na gestão de grandes conjuntos de imagens.
Os repositórios existentes não são capazes de gerir, armazenar e catalogar images de máquinas
virtuais de forma eficiente a partir de outras ”clouds”, mantendo um único repositório e serviço
centralizado. Esta necessidade torna-se especialmente importante quando se considera a gestĂŁo
de múltiplas ”clouds” heterogéneas. Na verdade, apesar da promoção extrema do ”Cloud Computing”, ainda existem barreiras à sua adoção generalizada. Entre elas, a interoperabilidade
entre ”clouds” é um dos constrangimentos mais notáveis. As limitações de interoperabilidade
surgem do fato de as ofertas de ”cloud” atuais possuĂrem interfaces proprietárias, e de os seus
serviços estarem vinculados às suas próprias necessidades. Os utilizadores enfrentam assim
problemas de compatibilidade e integração difĂceis de gerir, ao lidar com ”clouds” de diferentes fornecedores. A gestĂŁo e disponibilização de imagens de máquinas virtuais entre diferentes
”clouds” é um exemplo de tais restrições de interoperabilidade.
Esta dissertação apresenta o VISOR, o qual é um repositório e serviço de gestão de imagens de máquinas virtuais genérico. O nosso trabalho em torno do VISOR visa proporcionar um
serviço que nĂŁo foi concebido para lidar com uma ”cloud” especĂfica, mas sim para superar as
limitações de interoperabilidade entre ”clouds”. Com o VISOR, a gestão da interoperabilidade
entre ”clouds” Ă© abstraĂda dos detalhes subjacentes. Desta forma pretende-se proporcionar
aos utilizadores a capacidade de gerir e expor imagens entre ”clouds” heterogéneas, mantendo
um repositório e serviço de gestão centralizados. O VISOR é um software de código livre com
um processo de desenvolvimento aberto. O mesmo pode ser livremente personalizado e melhorado por qualquer pessoa. Os testes realizados para avaliar o seu desempenho e a taxa de
utilização de recursos mostraram o VISOR como sendo um serviço estável e de alto desempenho,
mesmo quando comparado com outros serviços já em utilização. Por fim, colocar as ”clouds”
como principal público-alvo não representa uma limitação para outros tipos de utilização. Na
verdade, as imagens de máquinas virtuais e a virtualização não estão exclusivamente ligadas a
ambientes de ”cloud”. Assim sendo, e tendo em conta as preocupações tidas no desenho de um
serviço genĂ©rico, tambĂ©m Ă© possĂvel adaptar o nosso serviço a outros cenários de utilização
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