As the emergence of SOA concept, web services has became a key technology to achieve the seamless system interoperability and collaborations with enterprises partners. Since many available web services provide overlapping or identical functionality, when it comes to composing a composite web service, a choice needs to be made for selecting an appropriate component web service. Dynamic web service selection refers to determining a subset of component web services to be invoked so as to orchestrate a composite web service. Previous work in web service selection usually assumes the invocations of web service operations to be independent of on another. But this assumption however does not hold in practice as both the composite and component web services often impose some orderings on the invocation of their operations to represent its business logic. Such orderings constrain the selection of component web services to orchestrate the composite web service. We therefore propose to use finite state machine (FSM) to model the invocation order of web service operations. We define a measure, called aggregated reliability, to measure the probability that a given state in the composite web service will lead to successful execution in the context where each component web service may fail with some probability. We show that the computation of aggregated reliability is equivalent to eigenvector computation. We also propose two strategies to select component web services that are likely to successfully complete the execution of a given sequence of operations. For our approach to work in a practical environment, the dominating composition language BPEL for specifying the operation invocation orders will be transformed into an abstract FSM. We also proposed a prototype for realizing our dynamic WS selection. Our experiments on a generated set of web service operation sequences show that our proposed strategies perform better than two baseline selection strategies.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0711107-103905 |
| Date | 11 July 2007 |
| Creators | Chen, Cheng-Hung |
| Contributors | Chih-Ping Wei, San-Yih Hwang, Wan-Shiou Yang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0711107-103905 |
| Rights | campus_withheld, Copyright information available at source archive |
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