Understanding Activity: Learning the Language of Action  Randal
Nelson and Yiannis Aloimonos  problem, both from the standpoint
of practical applications, and as a central issue in attempting
to describe the phenomenon of intelligence. On the practical
side, there are a large number of applications that would
benefit from improved machine ability to analyze activity. The
most prominent are various surveillance scenarios. The current
emphasis on homeland security has brought this issue to the
forefront, and resulted in considerable work on mostly low-
level detection schemes. There are also applications in medical
diagnosis and household assistants that, in the long run, may be
even more important. In addition, there are numerous scientific
projects, ranging from monitoring of weather conditions to
observation of animal behavior that would be facilitated by
automatic understanding of activity. From a scientific
standpoint, understanding activity understanding is central to
understanding intelligence. Analyzing