Semantic Technologies E-mail

The underlying philosophy within SOA4All for managing complexity and scalability is based on abstraction. DNS provides a first level of abstraction on the Web from IP numbers to more meaningful domain names. Google (and similar search engines) provide a second level of abstraction from specific domain names to keywords. In SOA4All, we lift services and their descriptions up to a third semantic based abstraction level. Since this level of abstraction deals with machine-understandable conceptualizations, the previous dependency upon human users is then decreased. The foundational model for this level of abstraction is the Web Service Modeling Ontology (WSMO). With such an ontological model, online services are then able to optimally interact – e.g. discover, compose, reason, mediate, etc. – with one another, reducing the strong dependency upon the human user. WSMO-Lite, developed in SOA4All, is inspired by WSMO, however, only focusing on a subset of it using it to define a gradual extension of SAWSDL.

The WSMO-Lite ontology builds on WSDL and SAWSDL, annotating Web service descriptions with semantics, intended for automation of tasks such as Web service discovery, composition, ranking and invocation. The main part of WSMO-Lite is a distinction of four kinds of service semantics - functional, nonfunctional, behavioral and information model. WSMO-Lite provides a set of RDFS classes for marking these types of semantics, as concrete semantic descriptions are attached to a WSDL file. Additionally, WSMO-Lite contains a minimal RDFS model of Web services (extracting the services, their operations and input/output messages from the WSDL), which serves as the basis for a registry of WSMO-Lite semantic Web service descriptions.

SOA4All is also developing MicroWSMO and hRESTS: two microformats for machine-readable semantic descriptions of RESTful Web services. There is currently no commonly accepted description language for RESTful services (which would be like WSDL for SOAP services), but every published RESTful Web service has HTML documentation. hRESTS is a microformat that introduces WSDL-like machine-readable structure in the HTML documentation of a service, on top of which MicroWSMO adds SAWSDL-like annotation properties. Both hRESTS and MicroWSMO can be interpreted in the WSMO-Lite minimal RDFS model of Web services. hRESTS and MicroWSMO constitute the basis for applying WSMO-Lite semantics to RESTful services. In SOA4All, RESTful and WSDL-based services are treated as equals.

By placing such ontologies at the heart of SOA4All, networked services are then managed via conceptualizations formalized in their semantic descriptions. And when a machine is capable of such conceptualizations – and subsequent inferences based upon these conceptualizations – then we approach a semi-automated solution, key to the scalability of the SOA4All platform.

Browse the "Ontology Yellow Pages" - URIs of ontologies developed in European research projects provide by the Semantic Technology and Ontologies Technical Group of the EC Software and Service Architectures unit focusing on Internet of Services collaboration activities. SOA4All is co-organizing the next Internet of Services Collaboration meeting in Brussels, Belgium from June 10-11th, 2009. More info.


Site map | Validate CSS | Validate XHTML