The serial Advances in Computers provides a medium for the in-depth presentation of subjects of both current and long-range interest to the
computer and information community. Within this framework, contributions
for appropriate articles have been solicited from widely recognized experts in
their fields. The time scale of the invitation is such that it permits a relatively
leisurely perspective. Furthermore, the permitted length of the contributions
is greater than many other publications. Thus, topics are treated both in depth
and breadth.