Yoshiaki Katada

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INTRODUCTION Alexander disease is a rare disorder resulting from a glial fibrillary acidic protein gene mutation which causes progressive degeneration of white matter. With the usual poor prognosis, there are few case reports with long-term follow-up. We report the five-year clinical course of Alexander disease in one case using serial magnetic resonance(More)
Neutral networks, which occur in fitness landscapes containing neighboring points of equal fitness, have attracted much research interest in recent years. In recent papers [20, 21], we have shown that, in the case of simple test functions, the mutation rate of a genetic algorithm is an important factor for improving the speed at which a population moves(More)
Neutral networks, which occur in fitness landscapes containing neighboring points of equal fitness , have attracted much research interest in recent years. In a recent paper [12], we have shown that, in the case of a very simple test function, the mutation rate of a genetic algorithm is an important factor for improving the speed at which a population moves(More)
— In recent years, not only ruggedness but also neutrality has been recognized as an important feature of a fitness landscape for genetic search. As it has been reported that the evolutionary dynamics on a fitness landscape with neutrality is clearly different from the canonical explanations, ruggedness alone might be inadequate describing it. Another(More)
Fitness landscapes which include neutrality have been conceptualized as containing neutral networks. Since the introduction of this concept, EC researchers have expected that a population can move along neutral networks without getting trapped on local optima. On the other hand, it has been demonstrated in tunably neutral NK landscapes that neutrality does(More)
In natural systems, animals discriminate an object through information coming from various receptors. In particular , object's figure and its motion pattern are known to be very important for quick and accurate discrimination. In this work, to give the similar ability of discrimination to an artificial agent, we examine whether artificial evolution is(More)
Neutral networks, which occur in fitness landscapes containing neighboring points of equal fitness , have attracted much research interest in recent years. In this work, we applied a standard GA and an extended GA with a variable mutation rate strategy to an abstract model of neutral networks in order to investigate the effects of selection pressure and(More)
In recent years, not only ruggedness but also neutrality has been recognized as an important feature of a fitness landscape for genetic search. Since the traditional theories based on the schema theory are not useful for problems including neutrality, new theoretical guidelines should be developed for effective genetic search. This research direction has(More)