2005 Fiscal Year Final Research Report Summary
Analysis on the codeword generating process of an arithmetic code and its application to source distribution transformer
| Project/Area Number |
16560326
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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 Field |
Communication/Network engineering
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| Research Institution | The University of Electro-Comunicat ions |
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Principal Investigator |
MORITA Hiroyoshi The university of electro-communications, the graduate school of information systems, professor, 大学院情報システム学研究科, 教授 (80166420)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIARA Mikihiko The university of electro-communications, the graduate school of information systems, research associate, 大学院情報システム学研究科, 助手 (90333492)
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| Project Period (FY) |
2004 – 2005
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| Keywords | arithmetic code / distribution transformer / target distribution / prefix free code / realtime coding / delay / stochastic model |
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| Research Abstract |
Throughout this project, we have obtained the following results on the codeword generating process of an arithmetic code.
2004-We evaluated theoretically, in the average sense, the redundancy included in a codeword generated by an arithmetic encoder. Moreover, we developed an algorithm to transform a sequence of information source symbols into another sequence with a given target distribution. This algorithm dissolve the following two practical problems that result from arithmetic codes:
1) when the decoding process halt.
2) how to reproduce exactly the original sequence from the transformed one.
2005-We considered the encoding/decoding processes for an information source that outputs symbols with a random interval and studied on the number of code symbols, that is, a fragment of a codeword, that an arithmetic encoder outputs at a unit time and the interval that it outputs them. From computer experiments, the interval of fragments can be modeled by geometric distribution while the length of each fragment has a different one. We observed the similar results in the decoder side. That is, the arithmetic decoder outputs a fragment of a codeword with a geometric distribution on its interval. However, our experiments showed that the length of fragment is neither individual nor geometrically distributed. Finally, we investigate the delay of the coding process and evaluated the probability distribution of the delay for a memoryless binary source.
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