| Budget Amount *help |
¥2,910,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥210,000)
Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
|
|---|
| Research Abstract |
The optimal linear codes problem consisting of the following two research problems is one of the fundamental problems in coding theory.
(1) Find new linear codes, which can correct more errors than the known codes.
(2) Prove or disprove the existence of very good codes (e. g. the Griesmer codes attaining the Griesmer bound) .
The following research problem is also important to tackle the above problems.
(3) Find new extension theorems for linear codes. For instance, extension theorems can be applied to find new codes from old ones and to prove the non-existence of some kind of Griesmer codes.
In this study, we first investigate the extendibility of ternary linear codes in detail. Then, employing the geometrical methods we have developed there, we found new extension theorems for quaternary linear codes and for 3-weight (mod q) codes over the field of order q.
For the problems (1) and (2) , we tackled the problem to find the minimum length n for which a code of length n, dimension k, and the minimum Hamming distance d over the field of order q for given q and k for all d. We have solved the problem especially for the cases (q, k) = (3, 6) and (5, 5) . Furthermore, we have determined the minimum length n for general (q, k) for some range of d. As for the problem (1) , we also did the research to find new codes with the aid of computers and we have found a lot of new linear codes over small fields.
|
