The German Society of Cybernetics organizes international conferences on selected interdisciplinary topics in regular 3-year intervals. The aim of these meetings is to bring together scientists who work in quite different disciplines, but are confronted with related problems and use the same or similar approaches. The topic of the 1983 conference which was held on March 23-25 at the University of Tiibingen came from a typical field of research in which engineers, biologists, and phYSicists share a common interest. We do not want to discuss here in detail the common principles which are used...