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Lookup NU author(s): Dr Anatoliy Gorbenko, Emeritus Professor Alexander RomanovskyORCiD
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.
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
