文章基本信息

标题：Model Checking Probabilistic Real-Time Properties for Service-Oriented Systems with Service Level Agreements
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作者：Christian Krause ; Holger Giese
期刊名称：Electronic Proceedings in Theoretical Computer Science
电子版ISSN：2075-2180
出版年度：2011
卷号：73
页码：64-78
DOI：10.4204/EPTCS.73.8
出版社：Open Publishing Association
摘要：The assurance of quality of service properties is an important aspect of service-oriented software engineering. Notations for so-called service level agreements (SLAs), such as the Web Service Level Agreement (WSLA) language, provide a formal syntax to specify such assurances in terms of (legally binding) contracts between a service provider and a customer. On the other hand, formal methods for veriﬁcation of probabilistic real-time behavior have reached a level of expressiveness and efﬁciency which allows to apply them in real-world scenarios. In this paper, we suggest to employ the recently introduced model of Interval Probabilistic Timed Automata (IPTA) for formal veriﬁcation of QoS properties of service-oriented systems. Speciﬁcally, we show that IPTA in contrast to Probabilistic Timed Automata (PTA) are able to capture the guarantees speciﬁed in SLAs directly. A particular challenge in the analysis of IPTA is the fact that their naive semantics usually yields an inﬁnite set of states and inﬁnitely-branching transitions. However, using symbolic representations, IPTA can be analyzed rather efﬁciently. We have developed the ﬁrst implementation of an IPTA model checker by extending the PRISM tool and show that model checking IPTA is only slightly more expensive than model checking comparable PTA.