Abstract-Web services exposing run-time behaviour that deviates from their behavioural specifications represent a major threat to the sustainability of a service-oriented ecosystem. It is therefore critical to verify the behavioural conformance of services during run-time. This paper discusses a novel approach for run-time verification of Web services. It proposes the utilisation of Stream X-machines for constructing formal behavioural specifications of Web services which can be exploited for verifying that a service's run-time behaviour does not deviate from what is defined in the specification. Our approach allows for checking both the control flow of a Web service and the values of the data in the generated responses. The paper also proposes a classification of Web services and discusses how different types of services can be verified at run-time. Finally, it presents a run-time monitoring and verification architecture and discusses how it can be integrated into different types of service-oriented infrastructures.

Abstract. Recent years have seen the utilisation of Semantic Web Service descriptions for automating a wide range of service-related activities, with a primary focus on service discovery, composition, execution and mediation. An important area which so far has received less attention is service validation, whereby advertised services are proven to conform to required behavioural specifications. This paper proposes a method for validation of service-oriented systems through automated functional testing. The method leverages ontologybased and rule-based descriptions of service inputs, outputs, preconditions and effects (IOPE) for constructing a stateful EFSM specification. The specification is subsequently utilised for functional testing and validation using the proven Stream X-machine (SXM) testing methodology. Complete functional test sets are generated automatically at an abstract level and are then applied to concrete Web services, using test drivers created from the Web service descriptions. The testing method comes with completeness guarantees and provides a strong method for validating the behaviour of Web services.

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Abstract. Web service behaviour is currently specified in a mixture of ways, often using methods that are only partially complete. These range from static functional specifications, based on interfaces in WSDL and preconditions in RIF, to business process simulations using executable state-based models such as BPEL, to detailed quality of service (QoS) agreements laid down in a service level agreement (SLA). This paper recognises that something similar to a SLA is required at the higher business level to govern the contract between service producers, brokers and consumers. We call this a business level agreement (BLA) and within this framework, seek to unify disparate aspects of functional specification, QoS and run-time compensation. We propose that the method for validating a web service with respect to its advertised BLA should be based on run-time service monitoring. This paper reports progress towards defining these goals.

Reliability and trust are fundamental prerequisites for the establishment of functional relationships among peers in a Collaborative