We have developed a highly integrated liquid-crystal-on-silicon microdisplay for virtual reality applications. The silicon panel of 704 576 pixels was designed and fabricated by a custom 0.35 µm complementary metal oxide semiconductor (CMOS) technology with emphasis on surface planarization. Topographic variation of less than 100 within the pixels was achieved. The pixel pitch was 9.6 µm, fill factor was 88% and display area was 0.36" in diagonal. Eight-bit digital data drivers and gamma-correction circuitry were integrated onto the silicon panel for true gray scale and full color representation. The display panel was assembled with a mixed twisted nematic and birefringence liquid crystal cell for high contract at CMOS compatible voltage. Chromatic characterization of the display using 3-color-in-1 light emitting diode (LED) as light source was performed. Contrast ratios on the pixel array were 95, 72 and 56, respectively, for red, green and blue colors at 3 V root-mean-squared voltage. In addition, a three-dimensional (3D) video stream in interlaced format was generated by a 3D modeling code for test and demonstration. Control logic was implemented to extract the left and right video frames and perform system timing synchronization. The silicon microdisplay was driven in frame inversion and by color sequence. With two sets of silicon microdisplays and eyepieces for each eye, we have demonstrated a 3D stereoscopic display based on the silicon microdisplay technology.

A novel fabrication process and materials of LC layers have been developed for three layer LCDs. It is based on LC/resist composite that can be applied to patterning LC layers with high resolution by conventional photolithography processes. Using this process, we fabricated a 2" matrix panel of three GH-LC layers stacked on a substrate for the fist time.

Low luminous efficacy is one of the major drawbacks of PDPs, with the discharge being the predominant limiting factor. Numeric simulations granting deeper insight in the core processes of the discharge are presented and the key parameters influencing the plasma efficiency are examined.

The encoding procedure that allows one to represent integers by binary vectors (codewords) in such a way that addition is replaced with the OR operation applied to these vectors is described. The codeword of the sum is constructed using the decoding algorithm. As a result, many of the transformations can be realized using parallel processing, and the method can be considered as a competitor to existing computer arithmetic.

A "dual-ring" network configuration is proposed in wavelength-division multiplexing (WDM) metropolitan area network (MAN). In the proposed architecture, a "sub-ring" using two fibers is added to the existing metropolitan WDM ring for flexible and cost effective addition of new nodes.

A new method of classification of sub-image blocks for digital image compression purposes using neural network is proposed. Two different classification algorithms are used to show their greater effectiveness than the conventional classification techniques. Simulation results are presented which demonstrate the effectiveness of the new technique.

The problem of self-timed implementation of Boolean functions is explained. The notions of combinational delay-insensitive code and delay-insensitive function are defined, giving precise conditions under which memoryless self-timed implementation of Boolean functions is feasible. Examples of combinational delay-insensitive code and delay-insensitive function are given. Generic design style, using standard CAD library, for constructing quasi delay-insensitive self-timed function blocks is suggested. Our design style is compared to other self-timed function block design styles.

We are interesting in the error exponent for source coding with fidelity criterion. For each fixed distortion level Δ, the maximum attainable error exponent at rate R, as a function of R, is called the reliability function. The minimum rate achieving the given error exponent is called the minimum achievable rate. For memoryless sources with finite alphabet, Marton (1974) gave an expression of the reliability function. The aim of the paper is to derive formulas for the reliability function and the minimum achievable rate for memoryless Gaussian sources.

With a view to virtual studio applications, we design an optimal grid pattern such that the observed image of a small portion of it can be matched to its corresponding position in the pattern easily. The grid shape is so determined that the cross ratio of adjacent intervals is different everywhere. The cross ratios are generated by an optimal Markov process that maximizes the accuracy of matching. We test our camera calibration system using the resulting grid pattern in a realistic setting and show that the performance is greatly improved by applying techniques derived from the designed properties of the pattern.

In this paper, two distinct optical network design approaches, namely mesh and multi-ring, for survivable WDM networks are investigated. The main objective is to compare these two design approaches in terms of network costs so that their merits in practical environments can be identified. In the mesh network design, a new mathematical model based on integer liner programming (ILP) and a heuristic algorithm are presented for achieving a minimal cost network design. In the multi-ring network design, a heuristic algorithm that can be applied to large network problems is proposed. The influence of wavelength conversion and the number of wavelengths multiplexed in a fiber on system designs are also discussed. Based on the simulation results, the redundancy quantities required for full protection in multi-ring approach are significantly larger in comparison to the minimal cost mesh counterpart.

A modified sequential acquisition scheme is proposed in this letter to avoid the significant high error probabilities (false alarm and missing probabilities) occurring with the conventional sequential acquisition scheme in direct-sequence spread-spectrum systems while a high frequency offset is present. A new estimator of Ek/N0 is also designed to effectively solve the problems caused by the channel fading effects. Extensive computer simulation results have indicated that the proposed technique can achieve the desired low error probabilities, and furthermore its performance is very close to that with the perfect channel estimation.

High-capacity multiwavelength ring networks with bidirectional WDM add/drop multiplexer (WADM) having built-in EDFAs is analyzed and demonstrated. All WDM channels can be added/dropped independently in each direction. The capacity of a bidirectional ring is found to be approximately twice that of an unidirectional ring. An eight-wavelength WADM is demonstrated for a data rate of 10 Gb/s per channel, providing an overall capacity of 80 Gb/s. The performance of the add/drop multiplexer is not degraded by backward backscattering light. The same WADM is also demonstrated to be able to serve as a bidirectional in-line optical amplifier.

In this paper, we propose path accommodation methods for unidirectional rings based on an optical compression time-division multiplexing (OCTDM) technology. We first derive a theoretical lower bound on the numbers of slots and frames, in order to allocate all paths among nodes. Three path accommodation algorithms for the all-optical access are next proposed to achieve the lower bound as closely as possible. Path splitting is next considered to improve the traffic accommodation. Finally, we analyze the packet delay time for given numbers of slots/frames, which are decided by our proposed algorithms. Numerical examples are also shown to examine the effectiveness of our proposed algorithms including path accommodation and path splitting methods.

For binary linear block codes, we introduce "multiple GMD decoding algorithm. " In this algorithm, GMD-like decoding is iterated around a few appropriately selected search centers. The original GMD decoding by Forney is a GMD-like decoding around the hard-decision sequence. Compared with the original GMD decoding, this decoding algorithm provides better error performance with moderate increment of iteration numbers. To reduce the number of iterations, we derive new effective sufficient conditions on the optimality of decoded codewords.

We present a design method of the simulation probability density function for a trellis-coded modulation (TCM) in an impulsive noise environment. The upper bound evaluation method for the TCM scheme cannot be applied to the lognormally distributed impulsive noise, since the Chernoff bound cannot be defined. Thus the error probability can only be estimated by a computer simulation. For an evaluation of a low error probability, importance sampling (IS) is an efficient technique. A design method of the simulation probability density function, which plays an important role in IS, is proposed for the noise. The effectivity is shown by a numerical example.

In this paper, we discuss on the realization of reduced peak power transmission for the multicarrier systems. Since the signals have large amplitude fluctuations in conventional multicarrier systems, signals amplified by a nonlinear amplifier are greatly distorted, resulting in severe performance degradation. In order to avoid this large amplitude fluctuation, we propose a scheme for reducing the nonlinear distortion by using the set of the signal point series which show low peak to mean envelope power ratio (PMEPR) value. In this system, one symbol is transmitted with multicarriers and the received signal is detected with maximum likelihood sequence detection.

The a-Si TFT characteristics were studied for process temperatures of as low as 100C. The a-Si TFT kept normal characteristics for process temperature of as low as 150C. The a-Si TFT bias temperature stability was evaluated and degradation of stability initiated at around 150C. The characteristics of a-Si TFT fabricated on plastic substrates were the same as those of a-Si TFT fabricated on glass substrates at low process temperature. TFT-LCD fabricated at a process temperature lower than the glass transition temperature of plastic substrates indicated good display image. These results indicate the possibility of fabricating TFT-LCD on plastic substrates, which would promote the application of a-Si TFT-LCD for mobile devices.

MF (medium frequency) radars (MFR) are powerful tools for understanding the upper atmosphere, by measuring horizontal wind velocity and electron density. This article introduces three MFR systems, two in Japan, Yamagawa (31.20N, 130.62E) and Wakkanai (45.36N, 141.81E) radars, and one at Poker Flat, Alaska (65.1N, 147.5W). Experimental techniques, and their observed results are briefly shown. Horizontal wind velocity was observed by those MFRs, in height ranges of 60-100 km (day) and 80-100 km (night) at Yamagawa and Wakkanai, while the data coverage is unusually low, >54 km (day) and >68 km (night), at Poker Flat. Comparison of MFR winds with temperature observed by a collocated Rayleigh lidar at Poker Flat shows consistency of those two instrument results in terms of atmospheric wave theory, implying validity of MFR data at such low altitudes. Electron density results at Poker Flat agree reasonably with International Reference Ionosphere model values at 74-84 km, and agree well with variation of cosmic noise absorption by the Poker Flat imaging riometer, suggesting valid electron density estimation by MFR at least below 80-85 km.

The application of subsurface radar using electromagnetic waves in the VHF band is wide and includes surveying voids under the ground and archaeological prospecting. To achieve a wider application range, the survey depth must be deeper. In this paper, a method of pulse compression using a chirp signal as one of the methods to fulfill this requirement is described, and its advantages and problems are discussed. First, a delay correlation method is proposed as a processing method of pulse compression. It converts RF band chirp signal directly into a pulse. Moreover, the method improves the S/N ratio by over 40 dB compared with conventional pulse radar. Therefore, it has the same detection ability as conventional pulse radar even though it uses less transmitting power. Next, the influences of RF amplifier saturation and underground propagation characteristics on the chirp signal are discussed; both are shown to have little influence on the detection ability of the method.

Meteor storms and showers are now considered as potential hazard in the space environment. Radar observations of meteors has an advantage of a much higher sensitivity over optical observations. The MU radar of Kyoto University, Japan has a unique capability of very fast beam steerability as well as a high sensitivity to the echoes from ionization around the meteors. We developed a special observation scheme which enables us to determine the orbit of individual meteors. The direction of the target is determined by comparing the echo intensity at three adjacent beams. The Doppler pulse compression technique is applied to improve the signal-to-noise ratio of the echoes from the very fast target, and also to determine the range accurately. The developed scheme was applied to the observation made during the Leonid meteor storm on November 18, 1998 (JST). Estimated orbital distribution seems to suggest that the very weak meteors detected by the MU radar are dominated by sporadic meteors rather than the stream meteors associated with the Leonids storm.