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Dependable Composite Web Services with Components Upgraded Online: Solutions, Models and Implementation

Lookup NU author(s): Dr Anatoliy Gorbenko, Professor Alexander Romanovsky

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Abstract

Achieving high dependability of Web Services (WSs) dynamically composed from component WSs is an open problem. One of the main difficulties here is due to the fact that the component WSs can and will be upgraded online, which will affect the dependability of the composite WS. The paper introduces the problem of component WS upgrade and proposes solutions for dependable upgrading in which natural redundancy, formed by the latest and the previous releases of a WS being kept operational, is used. The paper describes how 'confidence in correctness' can be systematically used as a measure of dependability of both the component and the composite WSs. We discuss architectures for a composite WS in which the upgrade of the component WS is managed by switching the composite WS from using the old release of the component WS to using its newer release only when the confidence is high enough, so that the composite service dependability will not deteriorate as a result of the switch. The effectiveness of the proposed solutions is assessed by simulation. We discuss the implications of the proposed architectures, including ways of ?publishing? the confidence in WSs, in the context of relevant standard technologies, such as WSDL, UDDI and SOAP.


Publication metadata

Author(s): Gorbenko A, Kharchenko V, Popov P, Romanovsky A

Publication type: Report

Publication status: Published

Series Title: School of Computing Science Technical Report Series

Year: 2004

Pages: 25

Print publication date: 01/12/2004

Source Publication Date: December 2004

Report Number: 879

Institution: School of Computing Science, University of Newcastle upon Tyne

Place Published: Newcastle upon Tyne

URL: http://www.cs.ncl.ac.uk/publications/trs/papers/879.pdf


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