| Project/Area Number |
13831001
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
NAKAGAKI Toshiyuki Hokkaido Univ., Res. Inst. For Electronic Science, Associate prof., 電子科学研究所, 助教授 (70300887)
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| Co-Investigator(Kenkyū-buntansha) |
UEDA Tetsuo Hokkaido Univ., Res. Inst. For Electronic Science, Prof., 電子科学研究所, 教授 (20113524)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Physarum / cellular computation / maze / self-organization / amoeboid movement / optimization / biological rhythm |
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| Research Abstract |
We reported that an amoeboid organism can solve a sort of optimization problem by using pattern formation of cellular rhythms.
We presented evidence that the giant amoeboid organism, the true slime mold, constructed a network appropriate for maximizing nutrient uptake. The body of the plasmodium of Physarum polycephalum contains a network of tubular elements by means of which nutrients and chemical signals circulate through the organism. When food pellets were presented at different points on the plasmodium it accumulated at each pellet with a few tubes connecting the plasmodial concentrations. The geometry of the network depended on the positions of the food sources. Statistical analysis showed that the network geometry met the multiple requirements of a smart network : short total length of tubes, close connections among all the branches (a small number of transit food-sites between any two food-sites) and tolerance of accidental disconnection of the tubes. These findings indicate that the plasmodium can achieve a better solution to the problem of network configuration than is provided by the shortest connection of Steiner's minimum tree.
Morphogenesis of the tube structure is induced depending on spatio-temporal patterns of cellular rhythms including mechanical, biochemical and electrical oscillations. Namely, geometrical morphology of the network is determined by the oscillation patterns. Chemical stimulation of the food to the organism leads to transition of the oscillation patterns since slight changes in oscillation frequency and cellular stiffness are induced around the stimulated site. Mechanism of the path finding by the organism is proposed in terms of pattern formation of the cellular rhythms. Along this line, a mathematical model for self-organization of transport network was proposed and discussed.
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