We present IREP++, a rule learning algorithm similar to RIPPER and IREP. Like these other algorithms IREP++ produces accurate, human readable rules from noisy data sets. However IREP++ is able to produce such rule sets more quickly and can often express the target concept with fewer rules and fewer literals per rule resulting in a concept description that is easier for humans to understand. The...

This paper introduces a new cellular automaton model of excitable media with improved treatments of (1) diiusion and wave propagation, and (2) slow dynamics of the recovery variable. The automaton is both computationally eecient and faithful to the underlying partial diierential equations.

Wave propagation governed by reaction-diffusion equations in homogeneous media has been studied extensively, and initiation and propagation are well understood in scalar equations such as Fisher’s equation and the bistable equation. However, in many biological applications the medium is inhomogeneous, and in one space dimension a typical model is a series of cells, within each of which the dyna...

Propagation of pulses in myelinated fibers may be described by appropriate solutions of spatially discrete FitzHugh-Nagumo systems. In these systems, propagation failure may occur if either the coupling between nodes is not strong enough or the recovery is too fast. We give an asymptotic construction of pulses for spatially discrete FitzHugh-Nagumo systems which agrees well with numerical simul...

We formalize Simplified Boardgames language, which describes a subclass of arbitrary board games. The language structure is based on the regular expressions, which makes the rules easily machine-processable while keeping the rules concise and fairly human-readable.

The following is an observation on the survival of dry cultures of pneumococci and streptococci for seven years under unusual and adverse conditions of storage. Dry cultures of 27 pneumococci and 10 streptococci prepared by the Division of Laboratories and Research of the Department of Health of New York (Wadsworth, 1939) were given to the author on 17th July, 1940. All the cultures were examin...

Abstract. We study (i) traveling wave solutions, (ii) the formation and spatial spread of synchronous oscillations, and (iii) the effects of variations of threshold in a system of integro–differential equations which describe the activity of large scale networks of excitatory neurons on spatially extended domains. The independent variables are the activity level u of a population of excitatory ...

A general strategy for fabricating thick, optically flat photopolymer recording media with high dynamic range (M/#) that exhibit low levels of recording-induced Bragg detuning for holographic data storage is presented. In particular, media with M/# values as high as 42 in 1-mm-thick formats are obtained. We believe that these results are the first demonstration of a holographic storage medium w...