This book contains all full papers presented at ACRI 2000, the Fourth International Conference on Cellular Automata for Research and Industry, held at the University of Karlsruhe (Germany), 4 - 6 October, 2000. The continuation of and growing interest in research on Cellular Automata models for real world phenomena indicates the feasibility of this approach. A quick glance at the table contents of this book shows that results came from such different areas as biology, economics, physics, traffic flow and urban development. This work is complemented by contributions on the implementation and evaluation of software for Cellular Automata simulation, which is a necessary (but of course in no way sufficient) ingredient for the successful application of Cellular Automata. Applying Cellular Automata without trying to understand their behavior, in depth would be an unfortunate development. But as properties and power in earlier years it was again one of the strong points of ACRI to bring together researchers not only from different application areas but also from theory. Of course, this is reflected by the list of accepted contributions which also comprise theoretical papers and even papers which certainly belong to the intersection of several fields. Examples are the generation and recognition of geometrical patters and the influence of possible failures on the power of CA which obviously are of relevance also to applications.

ACRI'96 is the second conference on Cellular Automata for Research and Industry; the first one was held in Rende (Cosenza), on September 29-30, 1994. This second edition confirms the growing interest in Cellular Automata currently present both in the scientific community and within the industrial applications world. Cellular Automata-based computational models, besides capturing the attention of scientists working in different fields, open new perspectives of intersection between different and historically distant areas of scientific knowledge, from Physics to Biology, to Computer Science. ACRI'96 aims at providing a forum both for researchers working in the Cellular Automata field, and for those who foresee the possibility to verify on concrete domains of application the impact of their solutions, as well as for those who are looking for a possibility of reflection upon the specific concept of parallel and distributed computation provided by Cellular Automata. This book contains the works presented at the conference. The invited papers cover different aspects of Cellular Automata. T. Worsch gives a classification of Cellular Automata mapping on the existent computational frameworks for the simulation of their behavior. One of the most mature areas where Cellular Automata showed their value is Physics: B. Chopard illustrates recent results on wave modeling, and some possible applications. According to the general purpose of ACRI'96 of transfering research results to the industrial world, F.