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>

In this paper we build a spatial, aspiration-based model of learning in the context of Cournot oligopoly from which we want to explore the conditions that lead to the emergence of cooperation among firms. We consider an economy consisting of many identical duopolies; each duopoly is placed on a...

The paper discusses the role of self-organizing phenomena like emergence of infrastructure and self-organizing criticality in a spatial economy. Some theoretical models are discussed and reviewed. Computer models in the form of simple cellular automata, similar to the game "Life" and Schelling's...

This paper investigates the properties of a local economy in which personal connections are important in finding jobs. The complementarities in the model generate an interesting nonlinear relationship between the distribution of human capital in the economy, the characteristics of the social...