See Bachelor projects

Semantic model for services


In order to allow machines (i.e., computer programs) to manipulate service descriptions at runtime, we have to add semantics to these descriptions. Typical examples of manipulations are service discovery, invocation and composition. Semantics can be defined using techniques like ontologies, which allow the definition and formalisation of vocabularies for the universe of discourse (real-life scope) of interest for the services being described. Typical examples of these techniques are OWL-S and SA-WSDL. However, services also have behaviour, which can be defined in terms of the interactions between this service and its environment (service users and other services) and the relationships between these interactions. Techniques used to define (service) behaviours can be process-based, like BPMN, PPEL, Petri Net, etc., or state-based, like FSM and LTS.


Currently there are two important directions in which semantics are been added to services, namely from an ontological point of view (e.g., OWL-S, SA-WSDL) and from a behavioural point of view (e.g., Petri Net semantics for BPMN). However, it is important that these two directions are combined and result in a consistent foundation semantics for service design and analysis. In this project the students will study these two forms of semantics, and devise a theory or framework that combines them in a consistent way. This theory or framework will be illustrated with a simple example.


  • Literature study on service semantics and its related technologies (Service-oriented architecture, web services, REDF, OWL, OWL-S, SA-WSDL, BPMN, Petri Net, LTS)
  • Development of an initial theory to unify ontological and behavioural service descriptions.
  • Evaluation of this theory with a (simple) use case. If time permits some (simple) service manipulations using this theory could be demonstrated.


  1. WC3. Semantic Annotations for WSDL and XML Schema. W3C Recommendation 28 August 2007.
  2. WC3. OWL-S: Semantic Markup for Web Services. W3C Member Submission 22 November 2004.
  3. Christian Stahl. A Petri Net Semantics for BPEL. Humboldt-Universität zu Berlin
  4. Markus Fronk, Jens Lemcke. Expressing SemanticWeb Service Behavior using Description Logics. In Proc. of European Semantic Web Conference (ESWC).2006.


Luís Ferreira Pires