ABSTRACT
Statement of the Problem Scientific inquiry often involves the study of the dynamics of physical systems. Change in global temperature, in atmospheric ozone, in wetlands and in coastal barrier islands are just a few examples of changing phenomena that have been brought to public attention by the media. To study change, it must first be detected. This may be accomplished by comparing sequences of recorded data that have been stored in a database. To the extent that such changes in system state are important in a model of the underlying phenomena, it may be useful to represent explicitly the observed change for later study. We are not concerned here with the detection of change, but rather focus on issues raised when we seek an explicit representation of the change itself in a database.
