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Service orientation is a mainstream paradigm in business applications and gains even greater acceptance in the very active field of eScience. In SOC service binding strategies have been defined to specify the point in time a service can be discovered and selected for use, namely static binding, dynamic binding at deployment or at run time, and dynamic service deployment. The basic assumption in all these strategies is that the software stack and infrastructure necessary to execute the services are already available. While in service-based business applications this is typically a valid assumption in scientific applications it is often not the case. Therefore, in this work we introduce a new binding strategy for services we call on-demand provisioning which entails provisioning of the software stack necessary for the service and subsequent dynamic deployment of the service itself. Towards this goal, we also contribute a middleware architecture that enables the provisioning of the software stack -functionality unavailable in conventional service middlewares. We demonstrate the approach and the capabilities of the middleware and the current state of the implementation of our approach. For this purpose we use an example application from the field of eScience that comprises a scientific workflow management system for simulations.

Abstract-Migrating an existing application to the Cloud is a complex and multi-dimensional problem requiring in many cases adapting the application in significant ways. Looking specifically into the database layer of the application, i.e. the aspect providing data persistence and manipulation capabilities, this involves dealing with differences in the granularity of interactions, refactoring of the application to cope with remote data sources, and addressing data confidentiality concerns. Toward this goal, in this work we present an application migration methodology which incorporates these aspects, and a decision support, application refactoring and data migration tool that assists application developers in realizing this methodology. For purposes of evaluating our proposal we present the results of a case study conducted in the context of an eScience project.

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Abstract-One of the key strengths of service oriented architectures, the concept of service composition to reuse and combine existing services in order to achieve new and superior functionality, promises similar advantages when applied to resources oriented architectures. The challenge in this context is how to realize service composition in compliance with the constraints defined by the REST architectural style and how to realize it in a way that it can be integrated to and benefit from existing service composition solutions. Existing approaches to REST service composition are mostly bound to the HTTP protocol and often lack a systematic methodology and a mature and standards based realization approach. In our work, we follow a comprehensible methodology by deriving the key requirements for REST service composition directly from the REST constraints and then mapping these requirements to a standard compliant extension of the BPEL composition language. We performed a general requirements analysis for REST service composition, defined a meta model for a corresponding BPEL extension, realized this extension prototypically and validated it based on a real world use case from the eScience domain. Our work provides a general methodology to enable REST service composition as well as a realization approach that enables the combined composition of WSDL and REST services in a mature and robust way.