Guido Scherp

Using UNICORE and WS-BPEL for scientific workflow execution in grid environments

Within the BIS-Grid project, a BMBF-funded project in the context of the German D-Grid initiative, we developed the BIS-Grid workflow engine that is based upon service extensions to UNICORE 6 to use an arbitrary WS-BPEL workflow engine and standard WS-BPEL to orchestrate stateful, WSRF-based Grid services. Although aimed at proving the feasibility of applying Grid technologies for business information systems integration, we illustrate that this engine is also well-suited for scientific workflow execution, making standard WS-BPEL-based tooling accessible for scientific workflows. In this paper, we describe using the BIS-Grid engine for the execution of scientific workflows. This includes a differentiation of scientific and business workflows in general and an analysis of the suitability of the BIS-Grid infrastructure to execute scientific workflows. We propose reusable WS-BPEL patterns for typical scientific workflow activities whereas job submission is focused. Finally, we prospect our future work.

An Orchestration as a Service Infrastructure Using Grid Technologies and WS-BPEL

The BIS-Grid project, as part of the German D-Grid initiative, investigates service orchestration using Grid service technologies to show how such technologies can be employed for information systems integration, especially when crossing enterprise boundaries. Small and medium enterprises will be enabled to integrate heterogeneous business information systems and to use external resources and services with affordable effort. In this paper, we discuss our Orchestration as a Service (OaaS) paradigm and present the BIS-Grid OaaS infrastructure. This infrastructure is based upon service extensions to the Grid middleware UNICORE 6 to use an arbitrary WS-BPEL workflow engine and standard WS-BPEL to orchestrate both plain Web services and stateful, WSRF-based Grid services. We report on the evaluation scenarios at our industrial application partners and on the applied service modeling methodology.

Towards a Model-Driven Transformation Framework for Scientific Workflows

Scientific workflows evolved to a useful means in computational science in order to model and execute complex data processing tasks on distributed infrastructures such as Grids. Many workflow languages and corresponding workflow engines and tools were developed to model and execute scientific workflows, without using established workflow technologies from the business domain. With the adoption of the service-oriented architecture (SOA) approach in modern Grid infrastructures, standardized and well-adopted workflow technologies from the business domain such as WS-BPEL are technically applicable to execute scientific workflows, too. In order to integrate business workflow technologies into the scientific domain, existing scientific workflow technologies for domain-specific modeling and established business workflows technologies for technical execution of scientific workflows can be combined. To do so, we propose an architecture for a transformation framework based on model-driven technologies that transforms a scientific workflow description at the domain-specific level to an executable workflow at the technical level.

WISENT: e-Science for Energy Meteorology

Our energy production increasingly depends on renewable energy sources, which impose new challenges for distributed and decentralized systems. One problem is that the availability of renewable energy sources such as wind and solar is not continuous as it is affected by meteorological factors. The challenge is to develop forecast methods capable of determining the level of power generation in near real-time in order to control power plants for optimal energy production. Another scenario is the identification of optimal locations for such power plants. In our collaborative project, these tasks are investigated in the domain of energy meteorology. For that purpose large data sources from many different sensors (e.g., satellites and ground stations) are the base for complex computations. The idea is to parallelize these computations in order to obtain significant speedup. This paper reports on an ongoing project employing Grid technologies in that context. Our approach to processing large data sets from a variety of heterogeneous data sources as well as ideas for parallel and distributed computing in energy meteorology are presented. Preliminary experience with several Grid middleware systems in our application scenario is discussed.

Workflow Service Extensions for UNICORE 6 --- Utilising a Standard WS-BPEL Engine for Grid Service Orchestration

The BIS-Grid project, a BMBF-funded project in the context of the German D-Grid initiative, focusses on realising Enterprise Application Integration using Grid technologies to proof that Grid technologies are feasible for information systems integration. Small and medium enterprises shall be enabled to integrate heterogeneous business information systems and to use external Grid resources and services with affordable effort. In this paper, we describe service extensions to UNICORE 6 to use an arbitrary WS-BPEL workflow engine and standard WS-BPEL to orchestrate stateful, WSRF-based Web Services, also called Grid Services. Thereby, we focus on how to combine the arbitrary workflow engine with UNICORE 6, and on how to access workflows and workflow instances. The workflows itself are also provided as Grid Services, realised by a Workflow Management Service that deploys Workflow Services within UNICORE 6, each wrapping a WS-BPEL workflow that is deployed in the arbitrary workflow engine.

Grid-based deployment and performance measurement of the Weather Research & Forecasting model

A system developed for benchmarking multi-processor Numerical Weather Prediction applications deployed on D-Grid resources is presented. The system currently serves to perform functional and non-functional software tests of the Weather Research and Forecasting (WRF) model used in the project WISENT. The resulting performance data and the input configurations are automatically published through a web portal to enable third-party comparisons with other, existing WRF deployments. The developed system relies on a self-contained, domain-independent software module for running MPI and other multi-processor Grid (Globus Toolkit 4) jobs that require a user-defined synchronized initialization and cleanup phase.

Grid-based processing of high-volume meteorological data sets

Our energy production increasingly depends on regenerative energy sources, which impose new challenges. One problem is the availability of regenerative energy sources like wind and solar radiation that is influenced by fluctuating meteorological conditions. Thus the development of forecast methods capable of determining the level of power generation (e.g., through wind or solar power) in near real-time is needed. Another scenario is the determination of optimal locations for power plants. These aspects are considered in the domain of energy meteorology. For that purpose large data repositories from many heterogeneous sources (e.g., satellites, earth stations, and data archives) are the base for complex computations. The idea is to parallelize these computations in order to obtain significant speed-ups. This paper reports on employing Grid technologies within an ongoing project, which aims to set up a Grid infrastructure among several geographically distributed project partners. An approach to transfer large data sets from many heterogenous data sources and a means of utilizing parallelization are presented. For this purpose we are evaluating various Grid middleware platforms. In this paper we report on our experience with Globus Toolkit 4, Condor, and our first experiments with UNICORE.