This page provides documents and resources from the DAML-Time effort, part of the DARPA Agent Markup Language project.
These resources are provided for research purposes and without any guarantees of safety or correctness. I hope you find them useful.
Please report problems or send suggestions to email@example.com.
This collaborative project, led by Jerry Hobbs, aims to develop a
representative ontology of time that expresses temporal concepts and
properties common to any formalization of time. The ontology is
formulated as a set of first-order predicate calculus axioms. These
axioms can be used as-is, or can be specialized to describe other,
more specific, temporal theories. In several places ontological
choices must be made. These are clearly indicated in the text and
optional axioms that might or might not be part of any
specific temporal ontology.
We have developed tools to automatically convert the axioms into a Lisp-like representation which is more or less a subset of KIF.
We have developed tools for automatically converting KIF (at
least, the subset of KIF used in the axioms) into DAML, using the
encoding described in
Proposal for Encoding Logic in RDF/DAML by McDermott, et al.
NOTE: The DRS encoding does not specify how to translate the unary predicate used in the current version of the DAML-Time axioms. Until this is resolved, the DAML version of the axioms cannot be generated.
DAML version of axioms (not currently available)
Feng Pan and Jerry Hobbs have developed an “entry” sub-ontology of time, expressed in OWL, that is much simpler than the full ontology and provides all of what most users would need, i.e., a vocabulary for expressing facts about topological relations among instants, intervals, and events, together with information about durations and about dates and times.
Additional DAML-Time documents:
Still to come:
Example of specifying standard Interval Temporal Logic using a subset of the common ontology (and additional axioms)
Stylesheet to print the DAML code back as KIF/Lisp, for validation of the translation if nothing else
This project, by George Ferguson and James Allen, is focused on
the development of concepts and tools for representing temporal
information. Temporal information is ubiquitous in real world
situations. It includes dates of events (
January 3, 2002,
Wednesday), durations of activities (
drive for twenty minutes,
wait about an hour), ordering between events (
wait for Fred
then drive to Rochester), and constraints between events (
touch the button while the switch is on,
only one flight can use
the runway at a time), among other things.
Our objectives in this project are (1) the development of a practical ontology and markup language suitable for representing temporal information in realistic situations and (2) the development of tools and algorithms to assist in the coding and use of temporal information.
Our approach is to build on formally well-defined and extensively-studied model of temporal representation, Interval Temporal Logic (the so-called Allen algebra of time). This and other work on formal temporal ontologies provides the foundation for development of the more practical ontology. This will be specifically designed to support the representation of certain types of temporal information that occur regularly and are of value to end users. The goal is a markup language that allows users to naturally indicate temporal information without being ontology or temporal reasoning experts.
Last change: 28 Jul 2003 by ferguson