A real-world semantic application typically is a heterogenous system. Its distributed architecture is often implied by requirements such as reliability and exchangeability. Building an application out of OWL-aware components requires a flexible but standardized interface. OWLlink (www.owllink.org), the successor of the well-known DIG protocol, is an implementation-neutral communication interface for OWL. It relies on OWL 2 and is likewise defined by a structural specification. Accompanying bindings specify how messages can be encoded and exchanged by a transport protocols. A key feature of OWLlink is its extensibility which allows to add functionality required by specific applications to the core protocol.
This half day tutorial at ISWC 2009 provides a practical introduction to OWLlink from the perspective of an application developer. It introduces the basic principles underlying OWLlink and explains how to manage reasoning engines, assert axioms, and to query inference results. Then two extensions are presented, one for retrieving previously told axioms and one for retracting axioms from the reasoner. Furthermore, an overview about existing OWLlink implementations is given and it is demonstrated how to employ the protocol on the code level using available OWLlink components. Finally, the tutorial describes how to specify your own OWLlink extension.
Target Audience and Prerequisite Knowledge
This tutorial aims at people interested in designing as well as building semantic applications based on OWL. The tutorial is comprehensible even for participants with a basic understanding of OWL. For the code level demonstration part of the tutorial some programming experiences would be helpful.