Low density parity check (LDPC) code, which is a special case of error correction code with sparse parity-check matrix, has the performance very close to the Shannon Limit.

The tangent stiffness matrix is obtained from the engineering strain and the principle for determining the limit point and bifurcation point is given.

While deciding the weight factors of the parameters, in the light of the limit of the general AHP, group judgment matrix is optimized by transfer matrix.