Stefan Gudenkauf

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.

A Reference Architecture for Cloud Service Offers

Cloud computing is a concept for the provisioning of internet-based information technology services as a common supply, similar to water supply, electric power supply, and telecommunication services. Several conceptual frameworks to describe and characterize Cloud service offers exist. As they are developed by different groups and organizations, they differ in their intention, type of formulation, the level of description, and in terms of which key issues of cloud service evaluation are addressed. To help overcoming the prevalent skepticism of enterprises regarding Cloud service offers, we surveyed different frameworks for Cloud service offer description. Based on this survey, we propose a consolidated reference architecture to uniformly describe and evaluate Cloud service offers, regardless of whether an organizations own offers or the offers of external providers are evaluated. In addition, we present Cloud Service Navigators (CSN) as a suitable visualization technique to describe visually and compare Cloud service offers and requests.

Space-based multi-core programming in Java

Multi-core processors require programmers to exploit concurrency in software as far as possible. Unfortunately, our current concurrency abstractions make multi-core programming harder than necessary because we have to reduce unintended non-determinism on a very low level of abstraction, for instance via synchronisation mechanisms. In this experience paper we analyse if space-based systems can mitigate multi-core programming in the Java programming language and present the Procol programming model that introduces the space-based choreography of active components, which internally orchestrate fine-grained workflow activities. The main contributions are (1) the Procol programming model, (2) benchmark results of the scalability of different tuple space implementation techniques that we evaluated on different multi-core architectures, (3) benchmark results of the scalability of two equivalent Mandelbrot applications for best-case measurements -- one implemented with the standard Java thread model, one with our Procol programming model. The conclusions drawn from these experiments are (1) tuple space data structures that scale reasonably well can be provided, (2) the performance overhead that Procol imposes is at least for the considered application a reasonable trade-off for the ease of programming provided for multi-core architectures.

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.

A coordination-based model-driven method for parallel application development

A continuous trend in computing is the demand for increasing computing performance. Provided that the problem space allows a solution that can be separated in parts to be computed independently, parallel systems offer a performance that exceeds that of sequential systems. To continue to improve processor performance, companies such as Intel and AMD have turned to hyper-threading and multi-core architectures [1]. With the advent of multi-core processors in the consumer market in 2005, parallel systems have moved out of the scientific niche and became a commodity [2]. Industry today is relying on hyper-threading and increasing processor count per chip as the new performance drivers since physical limitations impede further performance gains that are based on increasing clock speed and optimizing execution flow. These new performance drivers make it necessary to explicitly consider concurrency.

Opening Up Data Analysis for Medical Health Services: Data Integration and Analysis in Cancer Registries with CARESS

Dealing with cancer is one of the big challenges of the German healthcare system. Todays efforts regarding the analysis of cancer data incorporate detection of spatial clusters as well as complex health services research and quality assurance. Recently, guidelines for a unified evaluation of German cancer data were developed which demand the execution of comparative survival analyses [1]. In this paper, we present how the CARLOS Epidemiological and Statistical Data Exploration System CARESS, a sophisticated data warehouse system that is used by epidemiological cancer registries ECR in several German federal states, opens up survival analysis for a wider audience. We also discuss several performance optimizations for survival estimation, and illustrate the feasibility of our approach. Moreover we present the CARLOS Record Linkage System CARELIS, a companion tool to CARESS that enables matching new data against already existent disease reports in the ECR under consideration of potential cross references.

Opening up Data Analysis for Medical Health Services: Cancer Survival Analysis with CARESS

Dealing with cancer is one of the big challenges of the German healthcare system. Originally, efforts regarding the analysis of cancer data focused on the detection of spatial clusters of cancer incidences. Nowadays, the emphasis also incorporates complex health services research and quality assurance. In 2013, a law was enacted in Germany forcing the spatially all-encompassing expansion of clinical cancer registries, each of them covering a commuting area of about 1 to 2 million inhabitants [1]. Guidelines for a unified evaluation of data are currently in development, and it is very probable that these guidelines will demand the execution of comparative survival analyses.