Unified Service Description Language (USDL) and Linked USDL
The Unified Service Description Language (USDL) is a platform-neutral language for describing services.
The kinds of services targeted for coverage through USDL include: purely human/professional (e.g. project management and consultancy), transactional (e.g. purchase order requisition), informational (e.g. spatial and demography look-ups), software component (e.g. software widgets for download), digital media (e.g. video & audio clips), platform (e.g. middleware services such as message store-forward) and infrastructure (e.g. CPU and storage services).
Linked USDL, a remodelling effort around the same concepts, aims to better promote and support the use of USDL on the web.
Web Service Modelling Language (WSML)
The Web Service Modeling Language WSML is a language for the specification of ontologies and different aspects of Web services. In this respect WSML provides a syntax and semantics for the Web Service Modeling Ontology WSMO. WSML uses well-known logical formalisms in order to enable the description of various aspects related to Semantic Web Services.
Web Ontology Language for Services (OWL-S)
The Semantic Web should enable greater access not only to content but also to services on the Web. Users and software agents should be able to discover, invoke, compose, and monitor Web resources offering particular services and having particular properties, and should be able to do so with a high degree of automation if desired. Powerful tools should be enabled by service descriptions, across the Web service lifecycle. OWL-S is an ontology of services that makes these functionalities possible.
- Scope: Semantic web service description
- Versions:
- 1.0 (DAML, various universities)
- Tools and Libraries: plenty... including OWL-S Matcher, OWL-S Editor
- Status: finished 2004
Web Service Description Language (WSDL)
The Web Services Description Language Version (WSDL) is an XML language for describing Web services.
It enables one to separate the description of the abstract functionality offered by a service from concrete details of a service description such as “how” and “where” that functionality is offered.
At an abstract level, WSDL describes a Web service in terms of the messages it sends and receives; messages are described independent of a specific wire format using a type system, typically XML Schema.
- Scope: Syntactic signature description for procedural web services
- Versions:
- 1.0 (IBM Research, Microsoft)
- 2.0 (W3C)
- Tools and Libraries: plenty... including Eclipse WSDL Editor, Dynvoker
- Status: finished 2007
Web Application Description Language (WADL)
An increasing number of Web-based enterprises are developing HTTP-based applications that provide programatic access to their internal data. Typically these applications are described using textual documentation that is sometimes supplemented with more formal specifications such as XML schema for XML-based data formats. WADL is designed to provide a machine process-able description of such HTTP-based Web applications.