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D1.3.2 Service modelling and representation – Final version

This deliverable provides the final version of models for service descriptions in COMPOSE. The models are designed with the aim of publishing the service descriptions as Linked Data for advance service discovery, recommendation and composition. Guided by requirements coming from real-world services of the project’s use cases, our design approach is based on reusing and extending opportune existing ontologies in order to produce lightweight COMPOSE-specific vocabularies. The core ontology is the Minimal Service Model (MSM). MSM is a simplified and agnostic model to formally represent any kind of service and its operations including their input and output parameters. MSM enables description of WSDL-based Web services as well as RESTful APIs, which are the current trending approach to provide functionalities on the Web. For the COMPOSE project, MSM is used to represent COMPOSE application, Service Objects and external services to the platform through a unified concept of Service, in order to enable discovery, composition and recommendation of these different components in a seamless way. On top of the MSM, we use SAWSDL annotations as a standard way of attaching semantics to service descriptions. To structure the semantics, we use the WSMO-Lite service semantics ontology, which distinguishes four types of service semantics: functional, non-functional, behavioural, and information-model semantics. To enable actual invocation of Services, the service grounding information is modelled by the following ontologies. MSM-WSDL, which focuses on defining grounding of WSDL operations. The hRESTS microformat that provides grounding of generic Web APIs defined by plainHTML documentation. And, MSM-Swagger that is introduced to define the grounding of RESTful APIs described according to Swagger specification. Finally, additional COMPOSE-specific vocabularies have been designed to specifiy nonfunctional characteristics of Services, such as security, reputation, trust, provider popularity, and service business terms. COMPOSE-specific vocabularies for describing non-functional characteristics are developed up to the point needed by the COMPOSE Service Recommender (Deliverable D3.1.2.1).

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