Specification of an Ontology for Route Graphs

Abstract

Abstract. 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.

Modelling Models of Robot Navigation Using Formal Spatial Ontology

“…The second area of research we discuss is the Route Graph (RG: [9,2,10,3]). The RG was originally developed for practical robot navigation in real application contexts and so is also faced with the problems of mediating direct sensory input with abstract path control.…”

“…Route graphs have accordingly been characterized in a number of different ways and several alternative descriptions of the RG that are closer to actual robot control structures have also been given in the literature [10,11]. In our discussion here, however, we will draw particularly on the characterization of Krieg-Brückner et al in this volume [3]. This brings a number of advantages for us-in particular that the RG is already defined there in terms of several distinct ontological areas, similar to the approach seen for the SSH.…”

“…They include in their specification a width (provided by a Voronoi representation of the free space constituting a place: cf. [3,11]), and an origin that is used for defining the relative (angular) positions, or 'bearings' of all the nodes' incoming and outgoing edges. The origin constitutes a reference system for a place [2, p307]; orientation is therefore strictly local.…”

“…Whereas the original Route Graph showed more of its origins in a concrete structure for guiding mobile robot navigation by maintaining several rather distinct kinds of information, ranging from perceptual inputs to linguistic nodelabels, the latest specification described above (Section 2.2 and [3]), presents a far more ontologically rigorous account. Here, we see distinct information types being separated out, each allocated to its own appropriate ontological subdomain.…”

“…Several current ontologies include such graph theory modules and Krieg-Brückner et al [3] also provide such a formalization drawing on the algebraic specification language CASL (cf. [23]).…”