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Hideo KAWANO Atsushi MATSUMOTO Tanroku MIYOSHI
Liquid-crystal devices with in-plane switching electrodes (IPS-LCD) are superior to twisted nematic ones in their wider range of viewing angle, but show serious color shift with viewing angle. The color shift is a phenomenon governed by the three-dimensional orientation of liquid-crystal molecules. In order to evaluate such effects numerically, light wave propagation in the IPS-LCD is studied using a two-dimensional finite-difference time-domain method, where all six components of electromagnetic field are analysed and the three-dimensional properties of liquid-crystal materials are taken into account through the dielectric tensor. The computational space termination is provided by a combination of the uniaxial perfectly matched layer and periodic boundary conditions. It is found for the first time numerically that the color shift effects strongly depend on the asymmetrical profile of liquid-crystal orientation, which is originated from the small pretilt angle.
Naoya ONIZAWA Atsushi MATSUMOTO Takahiro HANYU
This paper introduces open-wire fault-resilient multiple-valued codes for reliable asynchronous point-to-point global communication links. In the proposed encoding, two communication modules assign complementary codewords that change between two valid states without an open-wire fault. Under an open-wire fault, at each module, the codewords don't reach to one of the two valid states and remains as “invalid” states. The detection of the invalid states makes it possible to stop sending wrong codewords caused by an open-wire fault. The detectability of the open-wire fault based on the proposed encoding is proven for m-of-n codes. The proposed code used in the multiple-valued asynchronous global communication link is capable of detecting a single open-wire fault with 3.08-times higher coding efficiency compared with a conventional multiple-valued code used in a triple-modular redundancy (TMR) link that detects an open-wire fault under the same dynamic range of logical values.
Naoya ONIZAWA Atsushi MATSUMOTO Takahiro HANYU
We have developed a long-range asynchronous on-chip data-transmission link based on multiple-valued single-track signaling for a highly reliable asynchronous Network-on-Chip. In the proposed signaling, 1-bit data with control information is represented by using a one-digit multi-level signal, so serial data can be transmitted asynchronously using only a single wire. The small number of wires alleviates the routing complexity of wiring long-range interconnects. The use of current-mode signaling makes it possible to transmit data at high speed without buffers or repeaters over a long interconnect wire because of the low-voltage swing of signaling, and it leads to low-latency data transmission. We achieve a latency of 0.45 ns, a throughput of 1.25 Gbps, and energy dissipation of 0.58 pJ/bit with a 10-mm interconnect wire under a 0.13 µm CMOS technology. This represents an 85% decrease in latency, a 150% increase in throughput, and a 90% decrease in energy dissipation compared to a conventional serial asynchronous data-transmission link.
Hiroshi KUBO Atsushi MATSUMOTO Atsushi SANADA
A particle for artificial magnetic materials in microwave frequency is proposed. It has simple structure composed of two parallel metal strips and is suitable to make a thin material extending in the transverse plane. In order to grasp the characteristic the effective permeability is formulated in the form of a transmission line. The characteristics of effective permeability are discussed based on the transmission line model for miniaturization and increase of the permeability. After discussing the reflection from materials with negative permeability or negative permittivity, a high impedance material is constituted. Total reflection with zero phase from the material composed of modified magnetic particles is measured in a waveguide.
Atsushi MATSUMOTO Yoshiaki SHIRAI Nobutaka SHIMADA Takuro SAKIYAMA Jun MIURA
We propose a method of face identification under various illumination conditions. Because we use image based method for identification, the accurate position of the face is required. First, face features are detected, and the face region is determined using the features. Then, by registering the face region to the average face, the horizontal position of the face is adjusted. Finally, the size of the face region is adjusted based on the distance of two eyes determined from all input frames. If the sizes of images for all faces are normalized into one size, the face length feature is lost in the normalized face image. The face is classified into three categories according to the face length, and the subspace is generated in each category so that the face length feature is preserved. We demonstrate the effectiveness of the proposed method by experiments.