This report is concerned with an implementation of a family of models of complex adaptive systems called Echo models. In what follows, you will find: An Introduction to Echo; Information on how to obtain, install and run the Echo system; A description of Echo's graphical interface and...

A class of minimal models is constructed that can exhibit several salient phenomena associated with T-Cell inoculations that prevent and cure auto-immune disease. The models consist of differential equations for the magnitude of two populations, the effectors {\it E} (which cause the disease),...

The problem of protecting computer systems can be viewed generally as the problem of learning to distinguish {\it self} from {\it other}. We describe a method for change detection which is based on the gereration of T cells in the immune system. Mathematical analysis reveals computational costs...

A simple model of the emergence of pillars in termite nests (Deneubourg, 1977) is modified to include several additional features that break the homogeneity of the original model: (1) a convection air stream that drives molecules of pheromone along a given direction, (2) a net flux of...

This note contains a description of John Holland's Royal Road function, which was presented at the Fifth International Conference on Genetic Algorithms in July 1993, and posted to the Internet Genetic Algorithms mailing list in August 1993 [2].

Self-organizing maps with variable local topology are shown to constitute a reasonably good heuristic to find approximate solutions to the NP-complete k-way graph partitioning problem, where a weighted graph has to be divided into k clusters of equal size while minimizing the total weight of...

The immune system is a complex system that learns, remembers what it has learned, and acts to protect us from a variety of pathogens. Here we address the question of how the immune system is able to recognize and learn about pathogens that can rapidly evolve and hence potentially change so as to...

The formal structure of evolutionary theory is based upon the dynamics of alleles, individuals and populations. As such, the theory must assume the prior existence of these entities. This existence problem was recognized nearly a century ago, when DeVries (1904) stated, ``Natural selection may...

The structure and evolution of the protein interaction network of the yeast Saccharomyces cerevisiae is analyzed. The network is viewed as a graph whose nodes correspond to proteins. Two proteins are connected by an edge if they interact. The network resembles a random graph, in that it consists...

We show that predicting the HPP or FHP III lattice gas for finite time is equivalent to calculating the output of an arbitrary Boolean circuit, and is therefore P-complete: that is, it is just as hard as any other problem solvable by a serial computer in polynomial time. <p> It is widely believed...</p>