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Subject: search.filters.subject.004Start date: 2000End date: 2009Institute: search.filters.UBSInstitut.Institut für Architektur von AnwendungssystemenAuthor: search.filters.author.Khalaf, Rania

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Now showing 1 - 3 of 3
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    Coordination protocols for split BPEL loops and scopes
    (2007) Khalaf, Rania; Leymann, Frank
    The document presents an approach to enable loops and fault handling, compensating scopes to be split among a set of BPEL processes running on different BPEL engines. A mechanism to split a scope or loop into multiple fragments is presented, then a protocol is defined that can be used to coordinate fragments of a loop or a scope so that those fragments run as if they had been in a single process. The requirements for running split scopes and loops are explained. For compensation, this paper focuses on explicit compensation and makes the assumption that compensation handing does not fail. Two protocols are defined such that they may be plugged into the WS-Coordination framework. The messages between the participant fragments and the coordinator are defined. The information about the participating processes that the coordinator needs to have is specified. An algorithm is provided to locate a fault handler in the hierarchy of scopes that can handle a particular BPEL fault. Additionally, the behavior of both participants and the coordinator are specified.
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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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    Note on syntactic details of split BPEL-D business processes
    (2007) Khalaf, Rania
    The document presents the syntactic details of the generation of process fragments created by the algorithm in [1], which defined the mechanisms for splitting a business process defined using a variant of WS-BPEL. The variant, BPEL-D, replaced BPEL’s variable style of data handling with explicit data links. We add new support in this note for syntactically splitting loops and scopes.