OntoEdit

• Developed by AIFB, University of Karlsruhe
• Try it at http://ontoserver.aifb.uni-karlsruhe.de/ontoedit/
• Developer's Product information
  

OntoEdit is an Ontology Engineering Environment supporting the development and maintenance of ontologies using graphical means. OntoEdit is built on top of a powerful internal ontology model. The internal ontology model can be serialized using XML, which supports the internal file handling.
This paradigm supports representation-language neutral modeling as much as possible for concepts, relations and axioms. Serveral graphical views onto the structures contained in the ontology support modeling the different phases of the ontology engineering cycle.

OntoEdit v0.6 supports F-Logic, RDF-Schema and OIL.
In the current version OntoEdit has an interface to the Karlsruher F-Logic Inference Engine (the backbone of OntoBroker), in the next version the FaCT system will be accessible from OntoEdit. Additionally, ontologies can be exported to object-relational database schemata and DTD's.
A mapping from concepts to words (e.g. for the connection to an natural language processing system) is defined using the domain lexicon view of OntoEdit.

What does OntoEdit offer the user?

The tool allows the user to edit a hierarchy of concepts or classes. These concepts may be abstract or concrete, which indicates whether or not it is allowed to make direct instances of the concept. A concept may have several names, which essentially is a way to define synonyms for that concept.

Concepts may participate in binary typed relations. Attributes of concepts are also considered to be relations. For this purpose, built-in types such as STRING, INTEGER and BOOLEAN are introduced. Relations can also be composed based on other relations.

Relations can be ordered in a hierarchy, which allows for inheritance/refinement of characteristics of relations. For example, the relation "hasRoom (x, y)" between a hotel and a room may be refined into the relation "hasDoubleRoom (x, y)" between a hotel and a double room, where "DoubleRoom" is a concept inheriting from the "Room" concept. Relations are refined by imposing restrictions on values, such as in the specified example, or on cardinality, for example by narrowing down a one-to-many relation to a one-on-one relation.

Each concept and relation can be documented explicitly within the ontology. This is especially important when exchanging ontologies.
Metadata of the ontology, such as the creator and the date of last modification, can also be stored within the ontology. This fixed set of attributes consists of the Dublic Core attributes as well as some ontology-specific attributes.

Transformation modules can be linked into the system, which allow to translate the ontology from its own general XML-based storage format to a more specific format. Currently an F-Logic transformation module is available, and work on an RDF module is being done.

The whole system is multilingual, meaning that each concept name, relation name or documentation string can be entered in several languages. Internally, the system uses unique concept and relation identifiers so that each statement remains clearly defined. Therefore, the names and descriptions serve merely as an external representation, which may have several alternatives.

The tool allows for copy-and-paste and cut-and-paste operations of parts of the ontology, perhaps from one ontology to another (multiple ontologies can be opened at the same moment).