A Framework for User Defined Periodic Calendars

Most contemporary calendaring and scheduling systems represent time using the Gregorian calendar. Systems that are more conscious of internationalization provide a choice of several predefined calendaring systems. We have observed that humans are constantly contriving new systems of time description that reflect specific domains of their activities, such as academic, agriculture, finance, sports calendars, and more. In this paper we investigate a model that offers the flexibility of adding an arbitrary time description system to an existing calendaring and scheduling application. Such a model allows organizations to define their own calendar and the periods of time that are significant to their activities, so that users within the organization can view, plan and reason about time in terms relevant to their domain.
Most of the formal symbolic definitions of calendars are logic oriented, and use constraints to represent valid dates, and to represent transformation rules between different calendars. This type of representation is not intuitive, and requires many hours of learning for a casual user to master. In this work we took an object oriented approach to representing calendars. The temporal concepts are represented by classes that are organized in hierarchies, and are related to each other via aggregation. A calendar definition is created by declaring instances of these classes, and the actual links between them.

By: Yael Shaham-Gafni, Daniel A. Ford

Published in: RJ10282 in 2003

LIMITED DISTRIBUTION NOTICE:

This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.

rj10282.pdf

Questions about this service can be mailed to reports@us.ibm.com .