Using DAML+OIL as a Constraint Language for Topic Maps
Eric Freese · 2003
Knowledge management has become hot new buzzword. Standards such as topic maps and Resource Description Framework (RDF) have been created to allow knowledge to be managed and interchanged. In all hype surrounding topic maps, one of oftmentioned applications is ability to create community-defined taxonomies and ontologies. Taxonomy is a fancy word meaning, the ordering of things into groups or categories. Ontology is a description of a set of concepts and relationships that can exist between those concepts. Topic maps provide much of what is needed to define a fairly robust taxonomy. However, there are still capabilities that are necessary to build robust ontologies that are not part of topic map standard. Over past year or so, World Wide Web consortium (W3C) and DARPA have been working to create a framework to model information ontologies contained on Web. The result of that work is known as DARPA Agent Markup Language + Ontology Interface Layer (DAML+OIL). DAML+OIL provides a rich set of constructs, using RDF, to create ontologies and mark up information to be machine readable and processable. Some of constructs are much more powerful than what is currently enabled by topic map model. These include: • The ability to define not only subclass-superclass relationships but also disjoint relationships. • The ability to place restrictions on when specific relationships are applicable • The ability to apply cardinality to relationships. The topic map standard provides several features that RDF cannot match, especially in its association model and ability to define scopes for information (even though there is still discussion about how scope should really work). While certain inferences about how objects are related can be derived from a topic map, DAML+OIL has extended RDF to do things topic maps can't. The constructs mentioned above would be very useful in topic maps to allow intelligent inferences about objects (whether or not they are topics or resources) and to accurately build a knowledge base from a set of information, be it a small corporate document repository or entire Web. This paper will demonstrate how DAML+OIL can be used to provide additional capabilities that are currently missing from topic map model. It will discuss possible additions to topic map model or its companion standard, Topic Map Constraint Language (TMCL), to enable DAML+OIL to process and enhance topic maps. It will also discuss methods for using DAML+OIL in conjunction with topic maps to take advantage of best from both worlds.