Transcript Presentations

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
etc
SUMO
Abstract Theory
of Space
(FOL)
Complete or Partial
Realization in
DAML / OWL /
RuleML / ...
Hayes &
Chaudhri
OpenCyc
NLP Extraction
Existing Standards
Techniques
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
SPACE
TIME
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