| Project/Area Number |
63850065
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
計算機工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SAWADA Yasuji Tohoku Univ. RIEC. Professor, 電気通信研究所, 教授 (80028133)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAJIMA Kouji Tohoku Univ. RIEC. Assistant Professor, 電気通信研究所, 助教授 (60125622)
MUROTA Junichi Tohoku Univ. RIEC. Assistant Professor, 電気通信研究所, 助教授 (70182144)
MIKOSHIBA Norio Tohoku Univ. RIEC. Professor, 電気通信研究所, 教授 (70006279)
NOGUCHI Shoichi Tohoku Univ. RIEC. Professor, 電気通信研究所, 教授 (80006220)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥16,700,000 (Direct Cost: ¥16,700,000)
Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1988: ¥15,200,000 (Direct Cost: ¥15,200,000)
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| Keywords | Neuron Computer / Integration / AD-Converter / Neuron Device / Synapse Device / C MOS / Threshold / Accurate Function / CMOS / LSI化ニューロン回路 / ヒドラ / 解離再集合体 / ヒステリシスしきい値素子 |
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| Research Abstract |
An AD-converter was fabricated as the first step of research for integrated neuron networks. By constructing an AD-converter of integrated neural network one can study various fundamental problems underlying for the fabrication of general integrated neural networks except for the plasticity of the synapses. The designed circuit was a 4-bit system composed of 4 neurons and 12 synapses. A neuron includes 2 paris of CMOS transistors, and a synapse includes a pair of CMOS and a nMOS. The value of a synapse weight is determined by the geometry of the gate, L/W. The circuit has outside control lines to modify the characteristics in case the processes create some unexpected deviation. The pattern size was designed by 4 micron rule considering the various possible difficulties in the processes. The fabricated neuron showed a threshold characteristics with a sigmoidal curve as expected. The output of the synapse was proportional to the input with a small off-set. The off-set would be removed by changing the condition of the channel doping. The AD-converter with symmetric synapses proposed by Hopfield was found to operate with wrong results as the solution was trapped by a local minimum. A new AD-converter with desymmetrized synapses was found to operate always correctly. Fabrication of a new AD-converter is under way.
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