In this paper, DSPs, of which memory addresses are pointed by special purpose registers (address registers: ARs), are assumed, and methods to derive an efficient memory access pattern for those DSPs proposed. In such DSPs, programmers must take care for efficient allocation of memory space as well as effective use of registers, in order to derive an efficient program in the sense of execution period. In this paper, memory addresses and AR update operations are modeled by an access graph, and a novel memory allocation method is presented. This method removes cycles and forks in a given access graph, and decides an address location of variables in memory space with less overhead. In order to utileze multiple ARs, methods to assign variables into ARs are investigated. The proposed methods are applied to the compiler for DSP56000 and are proved to be effective by generated codes for several examples.

Two drawbacks of pyramidal wavelet transforms for finite-length sequences are the lack of conservation of the support and the boundary effect. In this letter, the structure of cyclic wavelet transforms (CWT) is used to permute the input and output data to map them into a linear array. Systolic realization of cyclic wavelet packet transforms (CWPT) is also presented to adequately deal with finite-length sequences which have dominant information on high or median frequency channels. The VLSI architectures designed in this letter are very attractive because adaptive processing can be achieved by just programming the filter coefficients.

This paper describes a trial of evaluating the proper characteristics of multiple sound insulatain systems from their output responses contaminated by unknown background noises. The unknown parameters of sound insulation systems are first estimated on the basis of hte linear time series on an intensity scale, describing functionally the input-output relation of the systems. Then, their output probability distributions are predicted when an arbitrary input noise passes through these insulation systems.

This paper proposes a fast timing recovery method with a decision feedback equalizer for baudrate sampling. The proposed method features two special techniques. The first one is for coarse estimation of the sampling phase. Internal signals of the oversampled analog-to-digital converter at different phases are directly taken out for parallel evaluation. The second technique provides fine tuning with a phase-modification stepsize which is adaptively controlled by the residual intersymbol interference. Simulation results by a full-duplex digital transmission system with a multilevel line code show superiority of the proposed method. The coarse timing estimation and the fine tuning reduce 75% and 40% of the time required by the conventional method,respectively. The overall saving in timing recovery is almost 60% over the conventional method. The proposed method could easily be extended to other applications with a decision feedback equalizer.

In this paper, we present a distributed RAID style video server that addresses the problem of increasing video stream supplying capability in VOD systems. Distibuted RAID Stylemeans extending the RAID method usually applied to disks to the servers, so as to achieve improvements in performance and reliability. The great advantage of this architecture is that the linear performance improvement can be achieved by adding inexpensive servers of a diffusion model. We have implemented the RAID0 style and RAID4 style systems. A number of new features such as the array configuration method or the striping buffer are applied to them. A precise performance evaluation was made in a near practical environment, with more than 40 video streams. We tested the system, in both normal and degraded mode (server failure) and by checking frame drop rates as well as observing picture quality. An evaluation by simulation was also conducted. The results of the above evaluations agreed well with the calculation value, to confirm the feasibility of this architecture.

In this paper, we point out an architecture optimization problem for networks delivering services such as Video-On-Demand or, more precisely, two intertwined problems, i.e., the storage allocation of the videos among the storage nodes of the network and the choice of the network topology. We present and investigate the properties of a genetic algorithm which can handle such problems. This algorithm, as well as a greedy heuristics and simulated annealing, are then used to derive solutions in function of link and node cost parameters in a 36-node network. The results show that genetic algorithms are an effective class of algorithms for such problems, and possibly many other topology optimization problems.

The use of high-performance portable computers has become widespread. It is expected that many people will carry large amounts of multimedia information in these portable computers. In face-to-face communication, however, few systems are capable of exchanging multimedia information. Previously, we developed the Nomadic Collaboration Support System, which supports face-to-face communication through conversation and the distribution of documents. The system makes it possible for each participant in face-to-face communication to distribute electronic documents to other participants and edit them synchronously. However, it is often impossible for participants to obtain suitable amounts of information during face-to-face communication because of the difficulty in tailoring the documents for each participant. In this paper, we propose a technique to exchange hypertext documents on the Nomadic Collaboration Support System, which will allow each participant to obtain the most suitable amount of information possible from the distributor without his tailoring documents for each participant.

The up and coming multimedia services are based on real-time high-speed networks. For efficient operation of such services, real-time and precise network management is essential. In this paper, we show that presently available MIB designs are severely inadequate to support real-time network management. We point out and analyze the management constraints and bottlenecks. The concept of quality of management of management information is introduced and its importance in practical network management is discussed. We have proposed a new MIB architecture that will raise the quality of management information to meet the requirements of managing high-speed networks and multimedia services. Experimental results from a prototype implementation of the new MIB architecture are presented.

A multicast ATM switch with a new external copy module is proposed. The copy module, called copy-trunk, has two new functions to guarantee the QoS of P-MP cells: The delay priority control function and the output-cell-spacing control function. By using the delay priority control function, copied cells with high-priority are always released earlier than those with low-priority so as to avoid increasing the delay time of real-time traffic. The output-cell-spacing control function is used to reduce the burstiness of the output traffic. The output pattern is adaptively controlled by measuring the input load. The effects of these two controls are quantitatively described. The copy-trunk allows the multicast capability of a switch to be efficiently and economically increased to satisfy future traffic volume and services.

Internet is evolving to be an integrated service platform for promising future global information infrastructure. New multimedia services, e.g., Video-on-Demand, are expected to be provided on this platform, in conjuction with the existing rich information exchange and sharing services on Internet, such as E-mail, WWW. The paper proposes a service system architecture for Video-on -Demand on Internet, named MINS (Multimedia Internet Navigation System), which is capable of both realtime audio/video transmission and realtime and VCR like plya-out. MINS is composed of 1) servers maintaining both audio/video program lists and contents, and 2) clients retrieving the programs and play-out them. The paper focuses on the communication architecture in MINS, e.g., flow control, realtime media synchronization control, and audio/video session control. The performance of the prototype MINS is also evaluated in the paper.

We report recent progress in the development of Liquid Crystal(LC) materials for the TN-TFT and ECB-TFT technologies, which require LC materials with positive and negative dielectric anisotropy, respectively. Many kinds of new LC materials have been synthesized and have been evaluated based on their fundamental physical properties. We have succeeded in identifying new LC materials, and developing new LC mixtures based on those, so that the current typical requirements of TFT-LCDs e.g. fast switching times, low power consumption, good viewing angles and wide operation temperature ranges together with high reliability can be fulfilled.

This paper proposes a new duplication redundancy technology, 2 Transistors for 1.5 Gates, that is capable of automatic defect tolerance, so making large, high-resolution, color TFT-LCD panel fabrication both easy and economical. This redundancy technology with automatic defect tolerant capability has a low hardware overhead and is very capable of compensating for open circuit defects in a large active-matrix panel. This technology was confirmed by fabricating a 9.5-inch color TFT-LCD panel with 640480 pixels(960960 dots). This panel showed excellent display performance and produced pictures without defects. The yield improvement effect of this technology was also confirmed by calculation based on the Boltzmann statistics model. Consequently, this technology is clearly seen to have a yield improvement effect equal to defect density reduction of about one order, compared to non redundancy. This technology drastically reduces dot and line defects, enabling fabrication of large, high-resolution, color TFT-LCD panels at a relatively low cost.

The characteristics of a-Si bottom-gate TFT test devices with several kinds of inorganic "quasi-black matrix," such as metal, semiconductor, and insulator, on the top were investigated for various black matrix(BM) resistivities. In the Ia-Vg characteristics, for a BM sheet resistance of about1 1012 Ω/, a high off current and large Vth shift were observed due to the back-gating effects when the BM is charged up. Accrding to the ac dynamic characteristics, there was almost no leakage due to the capacitive coupling between source and drain after 16.6 msec(one frame) when the BM sheet resistance was above 7 1013 Ω/ . It was found that hydrogenated amorphous silicon germanium(a-SiGe:H) film, which has enough optical density, with the sheet resistance above the order of 1014 Ω/ is a promising candidate for an inorganic BM on TFT array.

In this work is first presented that a PDLC film with a ferroelectric alignment layer realizes a bistable switching in similar to the surface-stabilised ferroelectric liquid crystal display devices. Such a bistability is found to critically depend on the squareness parameter of the ferroelectric layer as well as such material properties of the dispersed nematics as the elastic and the dielectric constants. It is also found that there exists an appropriate elastic constant to improve the optical transmittance. The dependence of the distribution of the radii of the nematic droplets on the electro-optic bistability is also investigated in detail by means of the numerical computations assuming a fractal distribution. The fundamental electro-optic properties of the presently, proposed PDLC cells imply the advantage beyond the conventional PDLC without any ferroelectric alignment layer.

Super twisted nematic (STN) liquid crystal displays(LCDs) using spiral polymer aligned nematic (SPAN) liquid crystals have been achieved by photo-polymerization of some kinds of chiral monoacrylates in liquid crystalline hosts.The spiral polymer made of a chiral monoacrylate in STN LCD has effect to reduce the driving voltage without any disadvantages for the STN LCD. The relation of chemical structure of a chiral monoacrylate and nature of spiral polymer is discussed.

For the multi-gray shades image in the passive matrix type STN-LCDs, the method which combined space modulated patterns and frame rate control(FRC)with switched some frames has been used. Although bi-level display elements are used this method makes it possible to display a multi-gray shades image without resolution-loss for still-image, while the method has a fault to perceive interference of flicker at low frame rate, as is wellknown. However the measured quantitative data for flicker and frame frequency have hardly be published. With regard to frame rate control method which some typical space modulated patterns are combined, we measure critical flicker frame frequency(CFFF) with subjective experiments. This paper also discribes that the data are arranged to be shown in form of relationship with the screen luminance and the lowest frequency components included among ripples on times and also the ripples ratio. Our experimental study provides useful data for designing such kinds of display.

This paper describes the effects of operating temperature on delay time in a 1-V multi-threshold CMOS(MTCMOS) circuit, Delay-time analysis including the temperature factor shows that the delay-time variation of the CMOS circuit becomes amall for low-voltage operation and the variation is mainly determined by the threshold voltage and its variation-rate with temperature. As a design method of a MTCMOS circuit with both high-threshold and low-threshold MOSFETs, optimization of the low-threshold voltage at which the delay-time of the circuit is independent of operating temperature is described in detail. The validity of the design method is confirmed by the evaluation of a gate-chain TEG and a 1-V 12 K-gate digital-filter LSI fabricated with o.5-µm MTCMOS technology.

The effect of silicone vapour concentration on the contact failure was examined by using micro relays and motor brush-slip ring(commutator) contacts, [(CH3) 2SiO]4: D4 was used as a vapour source of silicone contamination. Because the influence of the vapour of the silicone on the contact surface can not be avoided at all times due to its gradual evaporation in the atmosphere. The contact failure caused by the silicone vapour was confirmed as formation of SiO2 on the contact surfaceby analysis of EPMA and XPS. A minimum limiting concentration level which does not affect contact reliability was found. This limiting level was 10 ppm(O.13mg/l). Validity of the limiting level was confirmed by the relationships among concentration, temperature, SiO2 film thickness and contact resistance. Furthermore, the effect of the degree of silicone polymerization on the limiting concentration was derived by an empirical formula. This silicone is found to have polymerization degree larger than D7: n=7. These results were confirmed by the contact failure data due to the silicone contamination.

This paper presents a method for mechanically transforming a parallel algorithm on an original network so that the algorithm can work on a target network. It is assumed that the networks are of cube-type such as the shuffle-exchange network, omega network, and hypercube. Were those networks isomorphic to each other, the algorithm transformation is an easy task. The proposed transformation method is based on a novel graphembedding scheme <φ: δ, κ, π, ψ>. In addition to the dilating operation δ of the usual embedding scheme <φ: δ>, the novel scheme uses three primitive graph-transformation operations; κ (= δ-1) for contracting a path into a node, π for pipelining a graph, and ψ (= π-1) for folding a pipelined graph. By applying the primitive operations, the cube-type networks can be transformed so as to be isomorphic to each other. Relationships between the networks are represented by the composition of applied operations. With the isomorphic mapping φ, an algorithm in a node of the original network can be simulated in the corresponding node(s) of the target network. Thus the algorithm transformation is reduced to routine work.

The medial axis transform (MAT) is an image representation scheme. For a binary image, the MAT is defined as a set of upright maximal squares which consist of pixels of value l entirely. The MAT plays an important role in image understanding. This paper presents a parallel algorithm for computing the MAT of an n n binary image. We show that the algorithm can be performed in O(log n) time using n2/log n processors on the EREW PRAM and in O(log log n) time using n2/log log n processors on the common CRCW PRAM. We also show that the algorithm can be performed in O(n2/p2 + n) time on a p p mesh and in O(n2/p2 + (n log p)/p) time on a p2 processor hypercube (for 1 p n). The algorithm is cost optimal on the PRAMs, on the mesh (for 1 p n) and on the hypercube (for 1 p n/log n).