Time Ontology Extended for Non-Gregorian Calendar Applications Editor: Mark Gahegan, University of Auckland, New Zealand Solicited review(s): Karl Grossner, Stanford University, USA; Brandon Whitehead, University of Auckland, New Zealand; one anonymous reviewer Simon J D Cox CSIRO Land and Water, PO Box 56, Highett, Vic. 3190, Australia
[email protected] Abstract. We have extended OWL-Time to support the encoding of temporal position in a range of reference systems, in addition to the Gregorian calendar and conventional clock. Two alternative implementations are provided: as a pure extension or OWL-Time, or as a replacement, both of which preserve the same representation for the cases originally supported by OWL-Time. The combination of the generalized temporal position encoding and the tem- poral interval topology from OWL-Time support a range of applications in a variety of cultural and technical set- tings. These are illustrated with examples involving non-Gregorian calendars, Unix-time, and geologic time using both chronometric and stratigraphic timescales. Keywords: temporal reference system, calendar, temporal topology, ontology re-use 1. Introduction spectively). Archaeological and geological applica- tions use chronometric scales based on years counted OWL-Time [6] provides a lightweight model for the backwards from ‘the present’ (defined as 1950 for formalization of temporal objects, based on Allen’s radiocarbon dating [15]), or named periods associat- temporal interval calculus [1]. Developed primarily ed with specified correlation markers [4,5,9]. to support web applications, date-time positions are Since OWL-Time only allows for Gregorian dates expressed using the familiar Gregorian calendar and and times, applications that require other reference conventional clock.