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DAML-Space. Jerry R. Hobbs USC/ISI Marina del Rey, CA. with contributions from Rusty Bobrow, Murray Burke, Dan Connolly, Dejing Dou, George Ferguson, Andrew Gordon, Pete Haglich, Pat Hayes, Adam Pease, Steve Reed, Richard Waldinger and others. Context.
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DAML-Space Jerry R. Hobbs USC/ISI Marina del Rey, CA with contributions from Rusty Bobrow, Murray Burke, Dan Connolly, Dejing Dou, George Ferguson, Andrew Gordon, Pete Haglich, Pat Hayes, Adam Pease, Steve Reed, Richard Waldinger and others
Context The Semantic Web requires common ontologies with wide acceptance and use. DAML-S: an ontology of services Development began February 2001 About a dozen people in inner circle Some people have explored using it Institutional status at W3C Version 0.9 just released DAML-Time: a temporal ontology Development began February 2002 Most work by 1-3 people Abstract theory 90% complete Mapping between DAML-Time and TimeML One site “about to” use it Want to build on this experience for a spatial ontology.
Aims A widely available ontology of geographical and other spatial properties and relations Provide convenient markup and query capabilities for spatial information in Web resources Adequate abstract coverage of most spatial applications (not necessarily efficient) Link with special purpose reasoning engines for spatial theories and large-scale GIS databases Link with various ontological resources (e.g., OpenCyc, SUMO, ...) and annotation schemes Link with various standards for geographical information (OpenGIS, GML, ...)
Structure of Effort Cohn Hayes & Chaudhri Abstract Theory of Space (FOL) etc Complete or Partial Realization in DAML / OWL / RuleML / ... SUMO OpenCyc NLP Extraction Techniques Existing Standards Annotation Standards
Some Principles Delimiting the effort: Not a theory of physical objects, properties of materials, qualitative physics Link with numerical computation, don’t axiomatize it Link with large geographical DBs, don’t duplicate them Navigate past controversial issues by Keeping silent on issue Provide easily exercised options Use textbook logic for abstract theory; DAML/OWL-ize predicate and function declarations Provide simple, useful entry subontologies
Topics SPACETIME Topology Topology Dimension -- Orientation & Shape -- Length, area, volume Duration Lat/long, elevation Clock & calendar Geopolitical subdivisions -- Granularity Granularity Aggregates, distributions Temporal aggregates
Topology Points, arcs, regions, volumes Closed loops and surfaces Ordering relations & “between” in arcs; directions on lines and loops Connectedness, continuity Boundaries & surfaces, interior & exterior, directed boundaries; “airspace above” Disjoint, touching, bordering, overlapping, containing regions (RCC8); location at Holes NOT open and closed sets NOT pathological topologies
Dimension and Orientation Abstract characterization of dimension, projections on component dimensions Links w topological notions of dimension Frames of reference: earth-based, person-based, vehicle-based, force-based Relative orientations: parallel, perpendicular Cartesian vs polar coordinate systems, bearing & range Transformations between coordinate systems Degrees of freedom Qualitative trigonometry: granularities on orientations 2 1/2 dimensions: elevation as 2nd class dimension, system mostly thought of as planar Elevation from sea level vs ground level Planar vs spherical geometry
Shape 2D vs 3D shapes Linking w shape descriptions in geographical databases Shape descriptors: round, tall, narrow, convex,... Relative shapes: rounder, sharper, ... Same shape as, negative-shape, fits-in Symmetry Links w functionality of shape In artifacts, shape is almost always functional In natural objects, shape often has consequences ? Texture
Size Length, distance, area, and volume Precise measures Alternate descriptions of size English-metric conversions Coarse granularities: order of magnitude, half order of magnitude, implied precision, qualitative measures (large, medium, small) relative to comparison set Encoding uncertainty: bounded error, egg yolk theories Uncertainty of location vs imprecise regions
Granularity A city can be viewed as a point, a region, or a volume. How should these different perspectives be accommodated? One approach: City is an entity with 3D, 2D, and 0D realizations. User can pick which one(s) to use. Build granularity considerations into spatial ontology from the beginning, not as an add-on.
Spatial Aggregates What are the most common ways of describing spatial aggregates? A qualitative theory of distributions. ? Texture
Geopolitical Regions Latitude and Longitude Natural geographical regions: Land masses: continent, island, ... Bodies of water: ocean, lake, river, ... Terrain features: mountain, valley, forest, desert, ... Political regions: Countries Political subdivisions: state, province, county, ... Municipalities: city, town, village, ... Residences and street addresses Other: Indian reservations, regulatory zones, ...
Linkages Exploit the large amount of research on spatial representation and reasoning OpenCyc, SUMO, Cohn, Galton, Hayes & Chaudhri, Hayes, Asher & Vieu, Egenhofer, Forbus Axiomatize best of this work in coherent fashion Link with existing large ontologies and annotation schemes SUMO, OpenCyc Ontology should bottom out in existing standards OpenGIS, GML
Target Applications As drivers for what has to be represented Flight map system, COA planning, trafficability Travel system involving lat/longs, political divisions, weather Alexandrian Digital Library Geologic and space (NASA) applications (3-D) Cell biology Image interpretation and description Robotics Virtual reality For some of these, we are collecting brief descriptions of the requirements for spatial representation and reasoning
Organization degree of community acceptance # of participants
Organization time to completion # of participants
Organization quality of ontology # of participants
Organization daml-spatial mailing list Web page - George Ferguson Coherent construction of abstract theories by small group of people Committee of interested persons in U.S. and Europe Email for commentary / feedback Telecons every 2 weeks to track issues/progress Presentations and discussion sessions at relevant workshops Early realizations of relevant parts of ontology in DAML Early construction of application-oriented entry subontologies