Petri-net model and minimum cycle time for updating a moving objects database

Moving objects database (MOD) contains the information (locations and times) of moving objects, e.g., taxicabs, trucks, airplanes, polar bears, etc. This information continuously changes and thus needs to be updated frequently in order to maintain the accuracy and usefulness of the information. This paper presents a fuzzy-timing Petri net model for updating a MOD and a method for estimating the time needed to update its database using the concept of the minimum cycle time of a Petri net. It is expected that the results of this paper are useful to study MOD design issues, such as the trade-off between update cost and information accuracy, and how often the database can be updated, given the number of moving objects, MOD system resources, delays of various MOD operations, etc.