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Publication Type: search.filters.UBSTyp.DissertationSubject: search.filters.subject.004End date: 2009Institute: search.filters.UBSInstitut.Institut für Architektur von Anwendungssystemen

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    Supporting business process fragmentation while maintaining operational semantics : a BPEL perspective
    (2008) Khalaf, Rania; Leymann, Frank (Prof. Dr.)
    Globalization and the increase of competitive pressures created the need for agility in business processes, including the ability to outsource, offshore, or otherwise distribute its once-centralized business processes or parts thereof. While hampered thus far by limited infrastructure capabilities, the increase in bandwidth and connectivity and decrease in communication cost have removed these limits. An organization that aims for such fragmentation of its business processes needs to be able to separate the process into different parts. Today, this is a manual, design-time endeavor. For example, it may use the concept of subprocesses as parts to be outsourced. However, there is often no way to foresee, in advance, which parts of the process need to be cut-off. Thus, today’s technology for outsourcing is static and not dynamic at all. Therefore, there is a growing need for the ability to fragment one’s business processes in an agile manner, and be able to distribute and wire these fragments so that their combined execution recreates the function of the original process. Additionally, this needs to be done in a networked environment, which is where ‘Service Oriented Architecture’ plays a vital role. ‘Service Oriented Architecture’ (SOA) is a relatively new approach to software that natively deals with the very dynamic, distributed, loosely coupled, and heterogeneous features of today’s networked environment, offering application functions as networked services. Web services is one instantiation of an SOA, consisting of a modular, layered stack of XML standards and corresponding implementations that address the different aspects of this environment. The standard covering business processes for Web services is the Business Process Execution Language for Web Services (also known as ‘BPEL’). Relevant characteristics of BPEL are that it is SOA-centric, has a scope construct that groups activities providing them with common behavior such as fault and compensation handlers, and combines graph and calculus based approaches to process modeling. This thesis describes how to identify, create, and execute process fragments without loosing the operational semantics of the original process models. It does so within the framework of the Web services stack of standards, BPEL in particular. The contributions are a categorization of existing Web services aggregation techniques, a meta-model of Web services business process mechanisms using a graph-based formalism, a solution for the automatic and operational semantics-preserving decomposition of such processes, and an architecture and implementation for a corresponding build-time and runtime environment.
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    An architectural decision modeling framework for service oriented architecture design
    (2009) Zimmermann, Olaf; Leymann, Frank (Prof. Dr.)
    In this thesis, we investigate whether reusable architectural decision models can support Service-Oriented Architecture (SOA) design. In the current state of the art, architectural decisions are captured ad hoc and retrospectively on projects; this is a labor-intensive undertaking without immediate benefits. On the contrary, we investigate the role reusable architectural decision models can play during SOA design: We treat recurring architectural decisions as first-class method elements and propose an architectural decision modeling framework and a reusable architectural decision model for SOA which guide the architect through the SOA design. Our approach is tool supported. Our framework is called SOA Decision Modeling (SOAD). SOAD provides a technique to systematically identify recurring decisions. Our reusable architectural decision model for SOA conforms to a metamodel supporting reuse and collaboration. The model organization follows Model-Driven Architecture (MDA) principles and separates long lasting platform-independent decisions from rapidly changing platform-specific ones. The alternatives in a conceptual model level reference SOA patterns. This simplifies the initial population and ongoing maintenance of the decision model. Decision dependency management allows knowledge engineers and software architects to check model consistency and prune irrelevant decisions. Moreover, a managed issue list guides through the decision making process. To update design artifacts according to decisions made, decision outcome information is injected into design model transformations. Finally, a Web-based collaboration system provides tool support for the framework steps and concepts. The SOAD framework is not only applicable to enterprise application and SOA design, but also to other application genres and architectural styles. SOAD supports use cases such as education, knowledge exchange, design method, review technique, and governance instrument.