1991 Fiscal Year Final Research Report Summary
Spread spectrum communication using chaos
| Project/Area Number |
01850070
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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 |
電子通信系統工学
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| Research Institution | Keio University |
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Principal Investigator |
SASASE Iwao EE Dept., Keio Univ., Assistant Prof., 理工学部・電気工学科, 専任講師 (00187139)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Toshimichi EE Dept., Hosei Univ., Associate Prof., 工学部・電気工学科, 助教授 (30178496)
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| Project Period (FY) |
1989 – 1991
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| Keywords | chaos / spread spectrum communication / quasi-random number / correlation property / discrete dynamical system / cryptogram |
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| Research Abstract |
This research aims at applications of chaos to information communication systems and it started for spread spectrum systems. It also covers cryptosystem and tends to develop into bioinformation processing systems. Up to the present, we have obtained the following results.
1. In order to investigate availability of random sequences from]-dimensional maps for spread signals, we tested correlation properties from Tent-Map and Cut-Map. Then it has clarified that the maps exhibit useful auto-correlation and useful cross-correlation in wide parameter region. Then the usefulness is held for mtlltiplexed cases. Moreover, 2-dimensional maps exhibit better correlation properties than 1-dimensional ones
2. Relating to information hiding, we developed an efficient cryptosystem by using an]-dimensional map. In this system, key, plain-text and chippertext correspond to a parameter, image and preimage, respectively. We have also shown that the system performance is improved dramatically by using a 2dimensional map which has both expanding and contracting dynamics.
3. We have analyzed 4-dimensional hysteretic circuits which relate to implementations of 2-dimensional maps. Then fundamental theories have been established for the trapping regions, observable chaos generation and bifurcations. We have also investigated chaos and-fractal responses from an artificial neural cell for future developments into biocomputations.
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