This paper describes the general concept of Route Graphs, to be used for navigation by various agents in a variety of scenarios. We introduce the concept of an ontology and describe the modelling of general graphs as an example. This approach is then applied to define a “light-weight ” ontology of Route Graphs in an indoors environment, giving at first just a taxonomy of (sub)classes and relations between them, as well as to other (spatial) ontologies. Finally, we show how to formalise ontologies using a First Order Logic approach, and give an outline of how to develop actual data structures and algorithms for Route Graphs.

In this paper we apply a formal ontological framework in order to deconstruct two prominent approaches to navigation from cognitive robotics, the Spatial Semantic Hierarchy of Kuipers and the Route Graph of Krieg-Brückner, Werner and others. The ontological framework is based on our current work on ontology specification, where we are investigating Masolo et al.’s Descriptive Ontology for Linguistic and Cognitive Engineering (DOLCE) extended particularly for space and navigation by incorporating aspects of Smith et al.’s Basic Formal Ontology (BFO). Our conclusion is that ontology should necessarily play an important role in the design and modelling of cognitive robotic systems: comparability between approaches is improved, modelling gaps and weaknesses are highlighted, re-use of existing formalisations is facilitated, and extensions for interaction with other components, such as natural language systems, are directly supported.

Abstract. This paper discusses the advantages of the Common Algebraic Specification Language (Casl) for the development of modular ontologies. Casl not only offers logics with a limited expressivity like description logic, but also e.g. first-order logic and modal logic. The central part of Casl is its powerful structuring mechanism, which is orthogonal to the logical formalisms. Hence the modularization applies uniformly to various logics and its extension Heterogeneous Casl (HetCasl) has even constructs for the combination of different logics. Additionally, the Heterogeneous Tool Set (Hets) is presented which enables reasoning and manipulation of Casl specifications. By presenting a detailed example ontology used for spatial knowledge representation the benefits of specification in Casl are discussed. Furthermore, a comparison with the OWL DL import mechanism is provided. 1

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