Styx grid services: lightweight middleware for efficient scientific workflows

The service-oriented approach to performing distributed scientific research is potentially very powerful but is not yet widely used in many scientific fields. This is partly due to the technical difficulties involved in creating services and workflows and the inefficiency of many workflow systems with regard to handling large datasets. We present the Styx Grid Service, a simple system that wraps command-line programs and allows them to be run over the Internet exactly as if they were local programs. Styx Grid Services are very easy to create and use and can be composed into powerful workflows with simple shell scripts or more sophisticated graphical tools. An important feature of the system is that data can be streamed directly from service to service, significantly increasing the efficiency of workflows that use large data volumes. The status and progress of Styx Grid Services can be monitored asynchronously using a mechanism that places very few demands on firewalls. We show how Styx Grid Services can interoperate with with Web Services and WS-Resources using suitable adapters.

A conceptual life event framework for government-to-citizen electronic service provision

In recent years, life event approach has been widely used by governments all over the world for designing and providing web services to citizens through their e-government portals. Despite the wide usage of this approach, there is still a challenge of how to use this approach to design e-government portals in order to automatically provide personalised services to citizens. We propose a conceptual framework for e-government service provision based on life event approach and the use of citizen profile to capture the citizen needs, since the process of finding Web services from a government-to-citizen (G2C) system involves understanding the citizens’ needs and demands, selecting the relevant services, and delivering services that matches the requirements. The proposed framework that incorporates the citizen profile is based on three components that complement each other, namely, anticipatory life events, non-anticipatory life events and recurring services.

Performance Analysis of a Semantics Enabled Service Registry

Service discovery is a critical task in service-oriented architectures such as the Grid and Web Services. In this paper, we study a semantics enabled service registry, GRIMOIRES, from a performance perspective. GRIMOIRES is designed to be the registry for myGrid and the OMII software distribution. We study the scalability of GRIMOIRES against the amount of information that has been published into it. The methodology we use and the data we present are helpful for researchers to understand the performance characteristics of the registry and, more generally, of semantics enabled service discovery. Based on this experimentation, we claim that GRIMOIRES is an efficient semantics-aware service discovery engine.

Performance Analysis of a Semantics Enabled Service Registry

Service discovery is a critical task in service-oriented architectures such as the Grid and Web Services. In this paper, we study a semantics enabled service registry, GRIMOIRES, from a performance perspective. GRIMOIRES is designed to be the registry for myGrid and the OMII software distribution. We study the scalability of GRIMOIRES against the amount of information that has been published into it. The methodology we use and the data we present are helpful for researchers to understand the performance characteristics of the registry and, more generally, of semantics enabled service discovery. Based on this experimentation, we claim that GRIMOIRES is an efficient semantics-aware service discovery engine.

Personalised Grid Service Discovery

The authors take a broad view that ultimately Grid- or Web-services must be located via personalised, semantic-rich discovery processes. They argue that such processes must rely on the storage of arbitrary metadata about services that originates from both service providers and service users. Examples of such metadata are reliability metrics, quality of service data, or semantic service description markup. This paper presents UDDI-MT, an extension to the standard UDDI service directory approach that supports the storage of such metadata via a tunnelling technique that ties the metadata store to the original UDDI directory. They also discuss the use of a rich, graph-based RDF query language for syntactic queries on this data. Finally, they analyse the performance of each of these contributions in our implementation.

Personalised Grid Service Discovery

We take a broad view that ultimately Grid- or Web-services must be located via personalised, semantic-rich discovery processes. We argue that such processes must rely on the storage of arbitrary metadata about services that originates from both service providers and service users. Examples of such metadata are reliability metrics, quality of service data, or semantic service description markup. This paper presents UDDI-MT, an extension to the standard UDDI service directory approach that supports the storage of such metadata via a tunnelling technique that ties the metadata store to the original UDDI directory. We also discuss the use of a rich, graph-based RDF query language for syntactic queries on this data. Finally, we analyse the performance of each of these contributions in our implementation.

Security Issues in a SOA-based Provenance System

Recent work has begun exploring the characterization and utilization of provenance in systems based on the Service Oriented Architecture (such as Web Services and Grid based environments). One of the salient issues related to provenance use within any given system is its security. In a broad sense, security requirements arise within any data archival and retrieval system, however provenance presents unique requirements of its own. These requirements are additionally dependent on the architectural and environmental context that a provenance system operates in. We seek to analyze the security considerations pertaining to a Service Oriented Architecture based provenance system. Towards this end, we describe the components of such a system and illustrate the security considerations that arise within it. Concurrently, we outline possible approaches to address them.

Modelling the Provenance of Data in Autonomous Systems

Determining the provenance of data, i.e. the process that led to that data, is vital in many disciplines. For example, in science, the process that produced a given result must be demonstrably rigorous for the result to be deemed reliable. A provenance system supports applications in recording adequate documentation about process executions to answer queries regarding provenance, and provides functionality to perform those queries. Several provenance systems are being developed, but all focus on systems in which the components are textitreactive, for example Web Services that act on the basis of a request, job submission system, etc. This limitation means that questions regarding the motives of autonomous actors, or textitagents, in such systems remain unanswerable in the general case. Such questions include: who was ultimately responsible for a given effect, what was their reason for initiating the process and does the effect of a process match what was intended to occur by those initiating the process? In this paper, we address this limitation by integrating two solutions: a generic, re-usable framework for representing the provenance of data in service-oriented architectures and a model for describing the goal-oriented delegation and engagement of agents in multi-agent systems. Using these solutions, we present algorithms to answer common questions regarding responsibility and success of a process and evaluate the approach with a simulated healthcare example.

Efficient Multi-Granularity Service Composition

Dynamic composition of services provides the ability to build complex distributed applications at run time by combining existing services, thus coping with a large variety of complex requirements that cannot be met by individual services alone. However, with the increasing amount of available services that differ in granularity (amount of functionality provided) and qualities, selecting the best combination of services becomes very complex. In response, this paper addresses the challenges of service selection, and makes a twofold contribution. First, a rich representation of compositional planning knowledge is provided, allowing the expression of multiple decompositions of tasks at arbitrary levels of granularity. Second, two distinct search space reduction techniques are introduced, the application of which, prior to performing service selection, results in significant improvement in selection performance in terms of execution time, which is demonstrated via experimental results.

Impactos da adoção das novas tecnologias BPM (business process management) nos processos governamentais

Este relatório consolida os trabalhos de pesquisa, desenvolvidos entre abril de 2005 e abril de 2006, sobre o estado de adoção e oportunidades para uso de novas tecnologias de informação em processos de governo. A ampliação de fronteiras, para além dos limites tradicionais das organizações, traz uma nova e mais forte demanda por flexibilidade que possibilite o tratamento integrado de organismos de diferentes constituições, arquiteturas e processos operacionais, sem falar nos diferentes sistemas de informações. Isto é ainda mais importante nas organizações públicas. Por outro lado, uma das principais características negativas dos órgãos públicos é a morosidade e a burocracia nos processos administrativos e de atendimento ao cidadão. A falta de uma visão tecnológica moderna, isto é, a falta de um Plano Diretor de Tecnologia da Informação (PDTI) voltada para novas soluções, como é o caso do BPM, alinhada à falta de integração entre os sistemas e processos, faz com que muitos órgãos governamentais estejam caminhando na contramão do desenvolvimento tecnológico. Este projeto de pesquisa reveste-se, portanto, de alto interesse, pois focaliza as possibilidades e impactos da adoção das novas tecnologias orientadas a processos e web services (BPM - Business Process Management e BPMS - Business Process Management Systems) na área governamental, bastante desprovida de soluções integradas de serviços aos cidadãos e empresas. Estas novas tecnologias trazem paradigmas completamente diferentes dos até aqui adotados na implementação de sistemas de informações e automação de processos. Apesar das dificuldades inerentes ao tratamento de um tema complexo e novo, mais ainda em organismos governamentais, acreditamos ter desenvolvido um trabalho bastante aprofundado, atendendo aos objetivos estabelecidos no plano original, com os necessários acertos de rota e foco dos trabalhos. Cremos, também, que este trabalho estabelece uma referência relevante no conhecimento relacionados à melhoria de processos de governo, com base em novas tecnologias. Como sub-produtos planejados e realizados, inseridos no caderno de anexos a este relatório, estão conteúdos já desenvolvidos para a edição um ou dois livros sobre o tema, diversos artigos produzidos, além de diversos eventos realizados na EAESP, envolvendo o tema do projeto, que proporcionaram a oportunidade de excelentes trocas de experiências. Este relatório, apresentado de forma objetiva e sintética, focalizando somente os principais aspectos tratados, é complementado por um extenso conteúdo complementar, entregue em um caderno de Anexos.

Tábula: uma framework para o desenvolvimento de aplicações REST

O desenvolvimento de aplicações web nos nossos dias é uma área importante, devido à disseminação do acesso à Internet e à utilização do browser como uma aplicação cliente universal. A aplicação web típica em HTML está sendo desafiada por tecnologias que permitem interfaces ricas que comunicam com um backend através de serviços. As ferramentas existentes para criar aplicações web ainda não adoptaram esta abordagem e o suporte existente é omissa em oferecer programadores ferramentas dinâmicas e fáceis de usar. Web Services tradicionais baseados em SOAP e Representacional State Transfer (REST) são alternativas para a comunicação entre o frontend e no backend. O REST ganhou recentemente visibilidade e a sua menor dificuldade de aprendizagem parece adequada para muitas aplicações. No entanto, a falta de normas leva a implementar serviços REST de muitas formas diferentes, mesmo na mesma plataforma, não existindo um acordo comum sobre como descrevê-los. Nesta dissertação, propomos uma nova framework para o desenvolvimento rápido de aplicações baseadas em REST. Para esse efeito, especificações e serviços de administração são apresentadas a fim de resolver os problemas de configuração de uma camada de serviços baseada em REST. Além disso, é apresentada uma nova abordagem para processar os pedidos, permitindo também a aplicação dos princípios AOP. Finalmente, é apresentada a implementação de uma framework que suporte estas especificações. Neste âmbito, temos por objectivo expor as potencialidades dinâmicas desta framework, tendo em vista a maximização da produtividade do programador na criação de aplicações baseadas em REST, minimizando o reinício do servidor e suportando dinamicamente uma ampla gama de mudanças.