• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.61-70
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• 2003

I-Business providers and customers have chosen the service availability as the most important technical parameter which should be included in their SLA to succeed in their business. This means that web Service availability management is crucial to the web-based service providers. Application availability is originally defined as a measure of the fraction of time during a defined period when the service provided is deemed to be better than user expectation of service performance. But, because most web service availability measurement tools simply monitor disconnected state, they do not satisfy user's expectation of extended availability concept. In this paper, We propose the web service availability measurement method which supports extended availability concept. It takes account of performance degradation of web service based on response time, and determines what is the cause of unavailability of the service. We developed a measurement tool, WebSerAvail.