Takashi Miyagoshi

Minimal Code(Error)-Trellis Module Construction for Rate-k/n Convolutional Codes: Extension of Yamada-Harashima-Miyakawa's Construction

Yamada, Harashima, and Miyakawa proposed to use a trellis constructed based on a syndrome former for the purpose of Viterbi decoding of rate-(n-1)/n convolutional codes. In this paper, we extend their code-trellis construction to general rate-k/n convolutional codes. We show that the extended construction is equivalent to the one proposed by Sidorenko and Zyablov. Moreover, we show that the proposed method can also be applied to an error-trellis construction with minor modification.

Simultaneous code/error-trellis reduction for convolutional codes using shifted code/error-subsequences

In this paper, we show that the code-trellis and the error-trellis for a convolutional code can be reduced simultaneously, if reduction is possible. Assume that the error-trellis can be reduced by shifting particular error-subsequences. In this case, if the identical shifts occur in the corresponding subsequences of each code path, then the code-trellis can also be reduced. First, we obtain pairs of transformations which generate the identical shifts both in the subsequences of the code-path and in those of the error-path. Next, by applying these transformations to the generator matrix and the parity-check matrix, we show that reduction of these matrices is accomplished simultaneously, if it is possible. Moreover, it is shown that the two associated trellises are also reduced simultaneously.

State-Complexity Reduction for Convolutional Codes Using Trellis-Module Integration

Assume that G(D) is a k0×n0 canonical generator matrix. Let G(L)(D) be the generator matrix obtained by integrating L consecutive trellis-modules associated with G(D). We also consider a modified version of G(L)(D) using a column permutation. Then take notice of the corresponding minimal trellis-module T(L). In this paper, we show that there is a case where the minimum number of states over all levels in T(L) is less than the minimum attained for the minimal trellis-module associated with G(D). In this case, combining with a shifted sectionalization of the trellis, we can construct a trellis-module with further reduced number of states. We actually present such an example. We also clarify the mechanism of state-space reduction. That is, we show that trellis-module integration combined with an appropriate column permutation and a shifted sectionalization of the trellis is equivalent to shifting some particular bits of the original code bits by L time units.

Fundamental Study about the Landscape Estimation and Analysis by CG

In recent years, the color of advertising signboards or vending machines on the streets should be harmonized with the surrounding landscape. In this study, we investigated how the colors (red and white) of the vending machines virtually installed by CG would affect the traditional landscape. 20 subjects estimated landscape samples in Hida-Furukawa by the SD technique. The result of our experiment shows that the vending machines have great influence on the surrounding landscape. On the other hand, we have confirmed that they can harmonize with the circumference landscape by the color to use.

Evaluation and Analysis of Traditional Town Landscape by Computer Graphics: Influence on Surrounding Landscape by Vending Machines@@@自動販売機による景観への影響について

In recent years, it has been viewed that the color of advertising signboards or vending machines on streets should be harmonized with the surrounding landscape. In this study, we investigated how (red and white) vending machines virtually installed into a scene by using CG would affect a traditional landscape. In addition, we investigated the harmony of the vending machine with the surrounding landscape and compared different cases in which there was advertisements or nothing. Landscape Cc;s with without vending machines of Hida-Takayama and Hida-Furukawa were evaluated by 20 subjects by using SD techniques. The results of our experiments show that the vending machines have a great influence on the surrounding landscape. On the other hand, we confirmed that they could be harmonized with the landscape if the right colors were used for their paint scheme.