Grid Workflow Modelling Using Grid-Specific BPEL Extensions

This paper discusses problems of Grid service composition using BPEL4WS. In particular, difficulties concerning the invocation of WSRF-based services are elucidated. A solution to this problem is presented by extending the BPEL specification, and an implementation based on the ActiveBPEL workflow enactment engine is described

Supporting Engineering Processes Utilizing Service-Oriented Grid Technology

Speeding up knowledge-intensive core processes in engineering and increas-ing the quality of their results is becoming more and more decisive, since economic pressure from national and international competitors and customers is rising. In particular, these demands exceed the organizational and infrastructural capacities of small and medium-sized enterprises (SME) by far. Hence, combining complementary core competencies across organizational boundaries is crucial for an enterprise's continuing success. Efficient and economically reasonable support of knowledge-intensive core processes in virtual organisations is therefore a predominant requirement for future IT infrastructures. The paradigm shift to service-orientation in Grid middleware opens the possibility to provide such support along the product lifecycle by employing a flexible software development approach, namely to compose applications from standard components, promising easier development and modification of Grid applications. In this paper, a service-oriented Grid computing approach is presented which aims at supporting distributed business processes in industry (see section 2 for industrial scenarios) from top level modelling, workflow design and exe-cution to actual Grid service code (presented in section 3). Parts of this gap between processes and code can be bridged by semi-automatically generated Grid service code. Orchestration of these Grid services is also automated by using a Grid-enabled workflow engine (see section 3). The feasibility of the proposed approach is demonstrated by presenting an exemplary process chain from the casting industry (see full paper)

Modeling urban growth by cellular automata

International audienceThe structural development of human settlements can be characterized as a complex highly feedbacketed process. The assumption that this process is governed by rather few fundamental laws stimulated a considerable research in the field of urban growth during the last decade. Aiming at the comprehension of the basic underlying dynamics different approaches from the field of self-organizing systems have been proposed. In this paper we present a "cellular model" of urban growth dynamics based on the work of White, Engelen and Uljee. As a starting point this model throws some light on the mechanism of urban growth. But even more important, it raises a lot of questions concerning the requirements for a sound modeling technique. One of these questions is how to assess the complex patterns produced by single simulation runs. Here we make especially use of fractal measures reducing the contained information to a manageable size. No doubt, this field of research is still in its infant state, and we are far from being able to hand a reliable tool to the decision maker. But promising results will stimulate future investigations which we hope will lead to a deeper insight into the nature of cities to improve the living conditions of their inhabitants

This document is under the terms of the CC-BY-NC-ND Creative Commons Attribution Grid Workflow Modelling Using Grid-Specific BPEL Extensions

This paper discusses problems of Grid service composition using BPEL4WS. In particular, difficulties concerning the invocation of WSRF-based services are elucidated. A solution to this problem is presented by extending the BPEL specification, and an implementation based on the ActiveBPEL workflow enactment engine is described.

This document is under the terms of the CC-BY-NC-ND Creative Commons Attribution Supporting Engineering Processes Utilizing Service-Oriented Grid Technology

Speeding up knowledge-intensive core processes in engineering and increasin