Biomedical subjects

Yukio-Pegio Gunji

Publications and source records attributed to Yukio-Pegio Gunji.

6 recordsLinked to original sources

PubMed2005

Flexibility in starfish behavior by multi-layered mechanism of self-organization.

Understanding animal behavior as a product of natural selection sometimes result in an underestimation of the animal's adaptability: lower animals with poor mental capabilities are usually considered to simply exhibit innate behavioral patterns. Self-organized behavior may exhibit both stability of certain behavioral patterns and flexibility in adopting those patterns. Thus, the self-organization processes of starfish arm and tube feet movements are investigated, by observing obstacle avoidance behavior and tube feet of moving starfish. As starfish have no central nervous systems, their behaviors are the result of certain self-organization processes. Starfish have hierarchically constructed motor organs consisting of arms and tube feet. The collective behavior of the tube feet does not function only as simple fluctuations in the arms' coordination. As a result, starfish seem to exhibit more versatile behavioral changes than expected from the original model of a self-organized behavior.

Animals↗

PubMed2004

Robust and emergent Physarum logical-computing.

There have been many attempts for realization of emergent computing, but the notion of emergent computing is still ambiguous. In an open system, emergence and an error cannot be specified distinctly, because they are dependent on the dis-equilibration process between local and global behaviors. To manifest such an aspect, we implement a Boolean gate as a biological device made of slime mold Physarum polycephalum. A Physarum (slime mold) Boolean gate could be an internally instable machine, while it has the potential for emergent computing. First, we examined whether Physarum Boolean gate works properly, and then examined its behaviors when the gate is collapsed in terms of hardware. The behavior of Physarum changes and self-repairing computing is achieved as a result. The self-repairing against internal failure is one of attributes of emergent and robust computing.

Animals↗

PubMed2004

Zipf's law in phonograms and Weibull distribution in ideograms: comparison of English with Japanese.

Frequency distribution of word usage in a word sequence generated by capping is estimated in terms of the number of "hits" in retrieval of web-pages, to evaluate structure of semantics proper not to a particular text but to a language. Especially we compare distribution of English sequences with Japanese ones and obtain that, for English and Japanese phonogram, frequency of word usage against rank follows power-law function with exponent 1 and, for Japanese ideogram, it follows stretched exponential (Weibull distribution) function. We also discuss that such a difference can result from difference of phonogram based- (English) and ideogram-based language (Japanese).

China↗

PubMed2004

Event detection by forward- and backward-prediction, illustrating the analysis for behaviors of black larder beetle Dermestes haemorrhoidalis Küster.

There are several studies that estimate the emergent event from the time series of behavior in some organisms. However, they do not focus on the emergent event itself. Our aim is to detect the emergent event from the time series of individual's behavior, focusing on the transition from predictable machinery behavior to purpose-oriented behavior and vice versa. We recorded the behavior of larvae and adults of black larder beetle. To detect the emergent event of the beetle, we defined a forward- and backward-prediction model. In the forward-prediction, the next state in the time series of behavior was interpreted by precedent behavior. In the backward-prediction, the previous state in the time series of behavior was interpreted by subsequent behavior. The time step with conspicuous peak of the co-intensity of errors in the forward- and backward-prediction was regarded as the timing at which the emergent event occurs. At the same time, the time series of states was estimated to determine whether noise was stationary or non-stationary. The attribute of noise was estimated using the Allan variance. The time series of the larvae's velocity of walking showed stationary noise. But in the case of the adults, whole time series contained 1/f noise. And, when time series was divided before and after the detected event, the noise changed from stationary to non-stationary and vice versa. These results suggest that development enables an individual to change the internal mechanism of walk considering the slight change of environment.

Animals↗

PubMed2003

Beyond input-output computings: error-driven emergence with parallel non-distributed slime mold computer.

The emergence derived from errors is the key importance for both novel computing and novel usage of the computer. In this paper, we propose an implementable experimental plan for the biological computing so as to elicit the emergent property of complex systems. An individual plasmodium of the true slime mold Physarum polycephalum acts in the slime mold computer. Modifying the Elementary Cellular Automaton as it entails the global synchronization problem upon the parallel computing provides the NP-complete problem solved by the slime mold computer. The possibility to solve the problem by giving neither all possible results nor explicit prescription of solution-seeking is discussed. In slime mold computing, the distributivity in the local computing logic can change dynamically, and its parallel non-distributed computing cannot be reduced into the spatial addition of multiple serial computings. The computing system based on exhaustive absence of the super-system may produce, something more than filling the vacancy.

Animals↗

PubMedDate not supplied

Active behavior and 1/f noise in shell-changing behavior of the hermit crabs.

Hermit crabs are known to carry a gastropod shell to prevent abdomen from injuring by predators and cannibalism. One can regard the shell as a boundary between inside and outside worlds for hermit crabs. We conducted an experiment in which hermit crabs without shells deal with artificial tubes. The situation without a shell requires a part of experimental setup to be regarded as inside by each hermit crab. We accept the distance of locomotion as the indication of the estimation process performed by an individual on parts of the experimental setup. As a result, behavioral hierarchy was found with respect to the way of constituting the boundary. At each level of hierarchy, active behavior produced 1/f noise in comparison with the passive one. It suggests that finding 1/f noise at each level of hierarchy may lead to a lower level of hierarchy in another situation.

Animals↗