WSDL – Web Service Definition Language  WSDL is used to describe, locate and define Web services.  A web service is described by: message format simple message exchanges (operations).  The description has 3 layers: 1. Interface for one or more operations for communication with the web service. 2. SOAP or HTTP is used for protocol binding. 3. Service endpoints that define the addresses for bindings.

UDDI – Universal Description, Discovery and Integration  UDDI is a web based registry of web services. It has 3 components: White pages – address, contract and identifiers. Yellow pages –categorization based on standard taxonomy Green pages – technical information  UDDI is based on keywords or fixed standard taxonomies.

WSMO - Web service modelling ontology  WSMO - Web service modelling ontology is an ontology for describing various aspects related to the SWS.  WSMO uses WSMF. WSMF consists of 4 main elements for describing SWS: Ontologies, goals, web service descriptions, mediators  WSML –provides a formal syntax and semantics for realising the 4 elements. It is based on formal logic.  WSML variants are divided in different levels: WSML – core, DL, Flight, Rule, Full  As mentioned UDDI is a registry for WSDL described web services. It is based on keywords. WSMO discovery uses the semantics in the WSMO description of a web service. WSMO can be requested and located in UDDI registers, but it is more effective to have a specific WSMO repository (register).

Grounding of WSMO in WSDL  WSDL is a syntactical contract.  WSMO describes functionality and behaviour and the descriptions are for finding and automatic service composition.  Where WSDL describes what data that can be exchanged, WSMO specifies what the result of the message exchange will be.  Web services have semantics is implicit in the client/server code.  WSMO has the semantics in the ontology.  We need SWS to interoperate with web services so also they can be automatically be composed and executed.  WSMO grounding includes that data in WSMO ontologies has been mapped to XML, and service descriptions in WSMO have to be related to the description in WSDL.

Protégé for WSMO

OWL / OWL-S  OWL is a description language  We have tree types of OWL: OWL FULL OWL DL OWL Lite  OWL-S is one of the major SWS description languages.  The OWL-S includes four main OWL-S classes: Service, Profile, Process and Grounding  As in WSMO we can ground OWL-S descriptions in a WSDL file.

Protégé for OWL

PATS Services  Location – where are you, and  Context - are you available?