CLIF Playground

We present in this article an ontological framework, which is specifically aimed at the development of natural language interfaces to agent systems in task-oriented applications. The ontology framework focuses on the representation of action concepts, since they provide, on the one hand, a suitable basis for natural language processing through the use of verb-centered case frames as semantic representation, and, on the other hand, they allow a connection to the action repertoire of the artificial agent system, which is supposed to respond to a user’s verbal requests with suitable actions. Action concepts are arranged in a taxonomical hierarchy and described in a formalism related to description logic. They are characterized through a set of parameters, which refer to object concepts in the knowledge base, and additional, formula-valued attributes specifying preconditions and effects, which define the dynamic aspects of an action 1 An Action Ontology Framework for Natural Language Interfaces to Agent Systems concept. This integrated representation of action and object concepts in the ontology allows us to provide a well-founded and grounded semantics for action concepts. The ontological framework has been used in the development of a variety of virtual agent systems with natural language interfaces, including an interior design system, an automated cook, a navigational and informational guide for our Computer Science Department, and several simulated household robots.