Dienstgüteunterstützung für Service-orientierte Workflows
Key: Ber07-1
Author: Rainer Berbner
Date: June 2007
Kind: @phdthesis
Abstract: The composition of services to workflows is one of the major challenges in the area of service-oriented computing. To meet business and user requirements it is crucial to manage the Quality of Service (QoS) of service-oriented workflows at the designing phase of a service composition as well as during its execution at runtime. Focusing on the QoS-aware service execution, this thesis introduces the QoS architecture WSQoSX (Web Services Quality of Service Architectural Extension) that supports late binding of services at runtime and dedicated monitoring mechanisms to avoid violations of Service Level Agreements (SLAs). As an extension of WSQoSX fast-performing heuristics for calculating an optimized execution plan of a workflow, considering user defined constraints and preferences, are designed and evaluated. Since services often do not perform as specified in their SLAs a replanning mechanism is introduced to ensure that a workflow execution plan remains feasible, valid, and optimal; subject to the user preferences. Within e-business scenarios, replanning mechanisms have to perform in real-time in order to avoid further delay to the workflow execution. Thus, in this thesis a fast and efficient heuristic-based replanning mechanism is proposed.

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