Semantic Web Services
Encyclopedia
Semantic Web Services, like conventional web service
s, are the server
end of a client–server system for machine-to-machine interaction via the World Wide Web
. Semantic services are a component of the semantic web
because they use markup which makes data machine-readable in a detailed and sophisticated way (as compared with human-readable HTML
which is usually not easily "understood" by computer programs).
standards for interoperation of web services specify only syntactic
interoperability, not the semantic
meaning of messages. For example, Web Services Description Language
(WSDL) can specify the operations available through a web service and the structure of data sent and received but cannot specify semantic meaning of the data or semantic constraints on the data. This requires programmers to reach specific agreements on the interaction of web services and makes automatic web service composition difficult.
Semantic web services are built around universal standards for the interchange of semantic data, which makes it easy for programmers to combine data from different sources and services without losing meaning. Web services can be activated "behind the scenes" when a web browser makes a request to a web server, which then uses various web services to construct a more sophisticated reply than it would have been able to do on its own. Semantic web services can also be used by automatic programs that run without any connection to a web browser.
A directory of Semantic Web Services providing semantic web service investigators with an index to projects, standards and bibliographical references of semantic web service proposals was created and is maintained by Dr. Khalid Belhajjame.
A Semantic Web Services platform that uses OWL (Web Ontology Language
) to allow data and service providers to semantically describe their resources using third-party ontologies is SSWAP
: Simple Semantic Web Architecture and Protocol.
SSWAP establishes a lightweight protocol (few OWL classes and predicates; see the SSWAP Protocol) and the concept of a "canonical graph" to enable providers to logically describe a service. A service is essentially a transformation of some, possibly null, input (or subject) to some, possibly null, output (or object). Services are semantically discoverable based on their subsumption hierarchies as well as their input and output data types.
(MEP), from the functionality consumer point of view.
Orchestration deals with describing how a number of services, two or more, cooperate and communicate with the aim of achieving a common goal.
Semantic Web Service frameworks:
Web service
A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...
s, are the server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
end of a client–server system for machine-to-machine interaction via the World Wide Web
World Wide Web
The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...
. Semantic services are a component of the semantic web
Semantic Web
The Semantic Web is a collaborative movement led by the World Wide Web Consortium that promotes common formats for data on the World Wide Web. By encouraging the inclusion of semantic content in web pages, the Semantic Web aims at converting the current web of unstructured documents into a "web of...
because they use markup which makes data machine-readable in a detailed and sophisticated way (as compared with human-readable HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
which is usually not easily "understood" by computer programs).
The problem addressed by Semantic Web Services
The mainstream XMLXML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
standards for interoperation of web services specify only syntactic
Syntax of programming languages
In computer science, the syntax of a programming language is the set of rules that define the combinations of symbols that are considered to be correctly structured programs in that language. The syntax of a language defines its surface form...
interoperability, not the semantic
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
meaning of messages. For example, Web Services Description Language
Web Services Description Language
The Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service provides a machine-readable description of how the service can be called, what parameters it expects and what data structures...
(WSDL) can specify the operations available through a web service and the structure of data sent and received but cannot specify semantic meaning of the data or semantic constraints on the data. This requires programmers to reach specific agreements on the interaction of web services and makes automatic web service composition difficult.
Semantic web services are built around universal standards for the interchange of semantic data, which makes it easy for programmers to combine data from different sources and services without losing meaning. Web services can be activated "behind the scenes" when a web browser makes a request to a web server, which then uses various web services to construct a more sophisticated reply than it would have been able to do on its own. Semantic web services can also be used by automatic programs that run without any connection to a web browser.
A directory of Semantic Web Services providing semantic web service investigators with an index to projects, standards and bibliographical references of semantic web service proposals was created and is maintained by Dr. Khalid Belhajjame.
A Semantic Web Services platform that uses OWL (Web Ontology Language
Web Ontology Language
The Web Ontology Language is a family of knowledge representation languages for authoring ontologies.The languages are characterised by formal semantics and RDF/XML-based serializations for the Semantic Web...
) to allow data and service providers to semantically describe their resources using third-party ontologies is SSWAP
SSWAP
Simple Semantic Web Architecture and Protocol is a lightweight, document-centric protocol and architecture for the Semantic Web...
: Simple Semantic Web Architecture and Protocol.
SSWAP establishes a lightweight protocol (few OWL classes and predicates; see the SSWAP Protocol) and the concept of a "canonical graph" to enable providers to logically describe a service. A service is essentially a transformation of some, possibly null, input (or subject) to some, possibly null, output (or object). Services are semantically discoverable based on their subsumption hierarchies as well as their input and output data types.
Choreography vs. orchestration
Choreography is concerned with describing the external visible behavior of services, as a set of message exchanges optionally following a Message Exchange PatternMessage Exchange Pattern
In software architecture, a messaging pattern is a network-oriented architectural pattern which describes how two different parts of a message passing system connect and communicate with each other....
(MEP), from the functionality consumer point of view.
Orchestration deals with describing how a number of services, two or more, cooperate and communicate with the aim of achieving a common goal.
Related technologies
Semantic Web languages:- Ontology Inference LayerOntology Inference LayerOIL can be regarded as an Ontology infrastructure for the Semantic Web. OIL is based on concepts developed in Description Logic and frame-based systems and is compatible with RDFS....
(OIL) - DARPA Agent Markup Language (DAML)
- DAML+OILDAML+OILDAML+OIL is a successor language to DAML and OIL that combines features of both. In turn, it was superseded by Web Ontology Language .DAML stands for DARPA Agent Markup Language. OIL stands for Ontology Inference Layer or Ontology Interchange Language...
- Web Ontology LanguageWeb Ontology LanguageThe Web Ontology Language is a family of knowledge representation languages for authoring ontologies.The languages are characterised by formal semantics and RDF/XML-based serializations for the Semantic Web...
(OWL) - Resource Description FrameworkResource Description FrameworkThe Resource Description Framework is a family of World Wide Web Consortium specifications originally designed as a metadata data model...
(RDF) - Web Services Modeling LanguageWeb Services Modeling LanguageWSML or Web Service Modeling Language is a formal language that provides a syntax and semantics for the Web Service Modeling Ontology ....
(WSML) - Web Services SemanticsWeb Services SemanticsWeb Services Semantics is a proposed extension to the WSDL standard. WSDL-S extends standard WSDL to include semantic elements which should improve the reusability of Web Services by facilitating the composition of services, improving discovery, and enabling the integration of legacy software...
(WSDL-S) - SAWSDLSAWSDLSemantic Annotations for WSDL and XML Schema is a 2007 published technical recommendation of W3C in the context of Semantic Web framework:...
Semantic Web Service frameworks:
- WSMF
- OWL-SOWL-SOWL-S is an ontology built on top of Web Ontology Language by the DARPA DAML program. It replaces the former DAML-S ontology. "OWL-S is an ontology, within the OWL-based framework of the Semantic Web, for describing Semantic Web Services...
- QuASAR.
- WSMOWSMOWSMO or Web Service Modeling Ontology is a conceptual model for relevant aspects related to Semantic Web Services.It provides an ontology based framework, which supports the deployment and interoperability of Semantic Web Services....
- IRS-III
- METEOR-S
- HALEY
- BioMOBYBioMOBYBioMOBY is a registry of web services used in bioinformatics. It allows interoperability between biological data hosts and analytical services by annotating services with terms taken from standard ontologies.- The BioMOBY project :...
(BioinformaticsBioinformaticsBioinformatics is the application of computer science and information technology to the field of biology and medicine. Bioinformatics deals with algorithms, databases and information systems, web technologies, artificial intelligence and soft computing, information and computation theory, software...
) - SSWAPSSWAPSimple Semantic Web Architecture and Protocol is a lightweight, document-centric protocol and architecture for the Semantic Web...
European projects
- Ongoing projects funded in the Seventh Framework Programme
- Ongoing and previous projects funded in the Sixth Framework Programme
- DIP
- Knowledge Web
- FUSION
- LUISA
- Transitioning Applications to Ontologies
- INFRAWEBS
- SEEMP
- SemanticGov
- SUPER
- Previous projects funded in the Fifth Framework Program
- Esperonto (IST-2001-34373) has developed ODE SWS, a toolset for design and composition of Semantic Web Services
- SWWS
- S-ten
- Adaptive Services Grid
- The ESSI or European Semantic Systems Initiative brings together six European FP6 projects working in the domains of Semantic Web Services and semantically empowered service-oriented architectureService-oriented architectureIn software engineering, a Service-Oriented Architecture is a set of principles and methodologies for designing and developing software in the form of interoperable services. These services are well-defined business functionalities that are built as software components that can be reused for...
s.- Adaptive Services Grid (ASG)
- Data Information and Process Integration with Semantic Web Services (DIP)
- Knowledge Web
- Semantic Knowledge Technologies (SEKT)
- Semantics Utilised for Process management within and between EnterprisesSuperSuper may refer to:* Super, a supernumerary actor on the stage, which is the equivalent of an "extra" in motion pictures and television.* Super, a building superintendent; a manager, maintenance or repair person, custodian or janitor, especially in the United States.* Super, a grade of gasoline*...
(SUPER) - Triple Space Communication (TripCom)
Other projects
- QuASAR. Quality Assurance of Semantic Annotations for Services. A project of the school of computer science, University of ManchesterUniversity of ManchesterThe University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
. - SWSI. The Semantic Web Services Initiative is an ad hoc initiative of academic and industrial researchers, many of which are involved in DARPA and research projects funded by the European Community.
- METEOR-S. A project of the LSDIS Lab, University of GeorgiaUniversity of GeorgiaThe University of Georgia is a public research university located in Athens, Georgia, United States. Founded in 1785, it is the oldest and largest of the state's institutions of higher learning and is one of multiple schools to claim the title of the oldest public university in the United States...
and Kno.e.sis Center, Wright State UniversityWright State UniversityWright State University is a comprehensive public university with strong doctoral, research, and undergraduate programs, rated among the 260 Best National Universities listed in the annual "America's Best Colleges" rankings by U.S. News and World Report. Wright State is located in Fairborn, Ohio,...
. - HALEY. A Web service composition project of the LSDIS Lab, University of GeorgiaUniversity of GeorgiaThe University of Georgia is a public research university located in Athens, Georgia, United States. Founded in 1785, it is the oldest and largest of the state's institutions of higher learning and is one of multiple schools to claim the title of the oldest public university in the United States...
- 3S@kno.e.sis. Semantics(Services, Science) : The 3S project at the kno.e.sis center, Wright State University, Dayton, OH.