Constrained coding for flash memories and its evaluation
| Project/Area Number |
15K15936
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Theory of informatics
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| Research Institution | Shonan Institute of Technology (2018)
The University of Electro-Communications (2015-2017) |
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Principal Investigator |
MANADA AKIKO 湘南工科大学, 工学部, 講師 (20631138)
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| Research Collaborator |
Morita Hiroyoshi 電気通信大学, 大学院情報理工学研究科, 教授 (80166420)
Ota Takahiro 長野県工科短期大学校, 情報技術科, 准教授 (60579001)
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2015: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
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| Keywords | フラッシュメモリ / 制約符号 / セル間干渉 / 禁止語 / グラフ理論 / 最大挿入レート / 制約影響を受けないセル / sum-rate / バランス制約 / 周期的な制約を含むシフト / 多次元制約 / グラフ表現 |
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| Outline of Final Research Achievements |
A flash memory is a non-volatile high-density storage medium that has been widely used in USBs or SSDs. Data is stored in a flash memory by adding electric charges to cells (floating gates) , and is read by quantizing the electric charges in the cells.
Increasing the amount of electric charges is easy and can be done by cells. However, decreasing the amount of electric charges is costly and affects the lifespan of flash memories. It is also known that the difference of electric charges between the cell and its adjacency cells can cause error when reading data. In this research, we proposed coding schemes that consider those issues, and analyzed the effeteness of these coding schemes.
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| Academic Significance and Societal Importance of the Research Achievements |
フラッシュメモリはUSBやSSD等，日常の様々な状況で使われており，データを正しく長期間保存できるようにすることが望ましい．今回の成果は主として離散数学の観点からの結果を与えており，高性能，高信頼性符号化に関する基礎的解析に貢献している．特に符号の容量（最大符号化率）やサムレート（１セルあたりにどれだけデータが書き込めるかを数値化したもの）等の重要数値に関して明確な値を与えたことは，今後改善案を思考する上での良い比較対象になると自負する．
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Report
(5 results)
Research Products
(10 results)
