Implementing Complex Calendar Systems in Java


In conventional systems, time-oriented data is modelled using a time stamp in each data element. However, time has an inherent structure that influences the data as well as its correct interpretation. One of the most important aspects of the structure of time involves calendric systems. To model this aspect, the concept of granularities has been introduced [Bettini et al., 2000].

Chronons of the discrete time domain can be mapped into different granularities, i.e. days can be mapped to weeks. Granularities can be mapped to other granularities, i.e. weeks to fortnights.

Figure 1: The Calendar Aspect in a Visualization from [Aigner, 2012]

Other aspects of the structure of time, like scope and determinacy, can be modelled using time primitives [Allen, 1983]. To include granularities in Java applications, the τZaman sytem has been developed [Urgun et al., 2007]. Our framework based on Java and prefuse [Heer, 2005] includes time primitives using the further advanced temporal objects [Aigner, 2011]. However, our current support for granularities is only based on the default calendric functions by Java.


We are looking for an eager advanced student who is interested in connecting the τZaman system to our CalendarManager interface as part of his or her master thesis. The thesis itself should be a treatise of how the concept of granularities can be implented in software development, with a comparison of conventional calendar implementations and τZaman.

Other information


Aigner, W., S. Miksch, H. Schumann, and C. Tominski, "Visualization of Time-Oriented Data", Springer Verlag London, 2011.

Allen, J.F., "Maintaining knowledge about temporal intervals", Communications of the ACM vol. 26 issue 11, pp. 832-843, 1983.

Bettini, C., Jajodia, S., and Wang, S, "Time granularities in databases, data mining, and temporal reasoning", Springer-Verlag New York Inc., 2000.

Heer, J., Card, S.K., and Landay, J.A, "Prefuse: a toolkit for interactive information visualization", Proceedings of the SIGCHI conference on Human factors in computing systems, ACM, pp. 421-430, 2005.

Urgun, B., Dyreson, C.E., Snodgrass, R.T., Miller, J.K., Kline, N.,  Soo, M.D., and Jensen, C.S. "Integrating multiple calendars using τZaman", Wiley Online Library vol. 37 issue 3, pp. 267-308, 2007.


Further information

Time-oriented data; Structure of Time; Calendars; τZaman; Java
Visual Analytics (VA)
Previous knowledge
Strong Java knowledge needed; prior knowledge about calendars would be helpful
Assigned as
Master thesis/Diplomarbeit