Tomonori IZUMI Ryuji KAN Yukihiro NAKAMURA
Recently, Plastic Cell Architecture (PCA) has been proposed as a hard-wired general-purpose autonomously reconfigurable processor. PCA consists of two layers, the plastic part on which sequential logic circuits are implemented, and the built-in part which induces the plastic part to dynamically reconfigure the circuits and transports messages among the circuits. The plastic part consists of an array of LUT-based reconfigurable logic primitives, each of which is connected only to adjacent ones. Combining logic and layout synthesis, we propose a new array-based algorithm to map logic functions into the PCA plastic part. This algorithm produces a folded array of sum-of-multi-input-complex-terms, especially for the PCA plastic part.
Hyun-Sool KIM Woo-Seok KANG Joong-In SHIN Sang-Hui PARK
This letter proposes a new detection method of human faces in gray scale image with cluttered background using a face template and elliptical structure of the human face. This proposed method can be applicable even in the cases that the face is much smaller than image size and several faces exist in one image, which is impossible in the existing one.
Ikuo KANEKO Sadayoshi TAGUCHI Toshiyuki KASHIWAGI
Conventional metal-glazed thick-film resistors are applied to Hybrid Integrated Circuits, chip resistors and others. These resistors are usually fired at a high temperature of around 850C on ceramic substrates. Recently, however, attempts have been made to fire some metal-glazed thick-film resistors at lower temperatures on glass substrates for application as the control resistors for the discharge current of dc Plasma Display Panels (PDPs). We have attempted to realize such low-firing-temperature thick-film resistors using Pb2Ru2O7-x as conductive particles, two kinds of lead-borosilicate glasses as binders, and three kinds of metallic oxide as additives, which are fired at 580C on a soda lime glass substrate. The electrical properties of the specimens, 16 kinds in all, fabricated from various combinations of binder glasses, additives and electrode materials have been measured. Effective dimensions of the specimen resistor are 0.25 0.25 mm2 or less in surface area, since extremely small size is required by PDPs. The effect of the combination of additive and binder glass on the conductive particles of Pb2Ru2O7-x has been examined in detail, together with the affinity for electrical conjunction between resistor and electrode.
Markus H. KLEIN Rob J. M. M. SNIJKERS Gerjan J. M. HAGELAAR
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.
Hajime NAKAMURA Koichi MIWA Michikazu NOGUCHI
After a bend structure has been obtained through application of an appropriate voltage, a pi-cell exhibits one of two stable structures: a bend structure if the applied bias is above a certain threshold ( 2 V), and a twist structure at a lower voltage. For use in an optical device, the pi-cell must be operated with the bend structure. It was found, however, that when the bias is switched quickly to a level lower than the threshold, a metastable structure exists for a few hundreds of milliseconds before relaxing to a twist structure. From dynamic optical transmittance analysis, this structure is considered to have a bend configuration. The temporary bend structure persists at lower voltages because it takes a while to initiate an energy redistribution from the bend structure to the twist. This is considered as a novel physical state, and is called a "dynamic bend structure. " It enables the pi-cell to be operated even if the bias is below the threshold voltage, provided that the device is biased at higher voltages for a fraction of each cycle to retain the bend structure.
Yuji NAKAZONO Toshiyuki TAKAGI Hiromoto SATO Atsushi SAWADA Shohei NAEMURA Atsutaka MANABE
Voltage holding property of liquid crystal (LC) cell for long period was investigated and the experimantal results were analyzed using a microscopic model considered the movement of ions in LC layer. The time dependent voltage decay curve observed in the experiment, which is not driven by the analysis with the conventional equivalent circuit comprised of the capacitance and the resistance, can be well explained by the microscopic model.
The transmission S-parameter between two dipole-elements is a measure to evaluate sites for measuring complex antenna factors (CAF). In this paper, the S-parameter between two dipole-elements on a ground plane is measured using a network analyzer with its TRL (Thru-Reflect-Line) calibration. The S-parameter is also calculated by the method of moment (MoM) and compared to the measurement results. The comparison shows that the calculated S-parameter is usable as a reference value in the evaluation of CAF measurement sites. As an example of the evaluation and selection of measurement sites, the transmission S-parameter on a finite ground plane is calculated using the hybrid method combined the geometrical theory of diffraction (GTD) and MoM. As a result, a preferable antenna setting on the finite ground plane is recommended.
Hirotsugu YAMAMOTO Syuji MUGURUMA Takeshi SATO Kasai ONO Yoshio HAYASAKI Yoshifumi NAGAI Yoshinori SHIMIZU Nobuo NISHIDA
By using full-color light emitting diode (LED) panel, we have been studying a stereoscopic full-color large television in broad daylight. In order to implement stereoscopic large display for the general public, optimum parameters of display elements and parallax barrier and viewing areas of stereoscopic display using parallax barrier are discussed. Although stereoscopic display with parallax barrier permits the viewer to view stereoscopic images without any special glasses, its viewing area is restricted by crosstalk and disappearing of pixels. Enlarged viewing areas, which are derived from the small ratio of light emitting region to pixel and a proper aperture ratio of parallax barrier, are analyzed. A model of a viewer standing toward the display is proposed because the viewer apart from the horizontal center of the display turns to the center point of LED display and this turning causes a deviation of viewer's eye position. Then, the allowable number of viewing locations is derived on "no crosstalk" and "no disappearance" conditions. The optimum aperture ratio of parallax barrier and the width of light emitting region is obtained through the optimization. The viewing area obtained from the analysis is confirmed by experiments using full-color LED panel. Relations between viewing area and the moire fringes is also discussed. The depth of the viewing area agrees the viewing distance where no moire fringe appears. Furthermore, possibility of display for the crowds is discussed.
Mitsushi IKEDA Yoshihisa MIZUTANI Sumio ASHIDA Keisaku YAMADA
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.
Ho Chi HUANG Kwok Cheong LEE Chun Kwan YIP Hon Lung CHEUNG Po Wing CHENG Hoi Sing KWOK
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.
Hideya TAKAHASHI Kenji YAMADA Eiji SHIMIZU
The visual reality of a holographic image has improved effectively by utilizing multicolor reconstruction procedure. This fact is applicable to a real-time three-dimensional display for a computer generated hologram (CGH). However, it is quite difficult to generate a CGH for multicolor imaging in real-time because a CGH contains essentially a huge amount of information, and increases further information produced by multiplying the number of primary colors for multicolor imaging. Moreover, the optical system is considerably complicated for the multicolor image reconstruction. In this paper, a new method is presented to reconstruct a three dimensional multicolor image from a CGH. In this method, three sub-holograms to reconstruct the primary color images are sampled respectively for reducing the amount of computation and realizing a simple optical system. Fringe patterns are displayed by only one spatial light modulator (SLM) and color crosstalk images are eliminated by a color filtering system for ensuring that each sub-hologram can be only illuminated by the light with an appropriate color. A multicolor imaging method from a CGH is proposed and also the experimental results are shown.
Gang ZHAO Shoji TATSUMI Ruoying SUN
Reinforcement Learning (RL) is an efficient method for solving Markov Decision Processes (MDPs) without a priori knowledge about an environment, and can be classified into the exploitation oriented method and the exploration oriented method. Q-learning is a representative RL and is classified as an exploration oriented method. It is guaranteed to obtain an optimal policy, however, Q-learning needs numerous trials to learn it because there is not action-selecting mechanism in Q-learning. For accelerating the learning rate of the Q-learning and realizing exploitation and exploration at a learning process, the Q-ee learning system has been proposed, which uses pre-action-selector, action-selector and back propagation of Q values to improve the performance of Q-learning. But the Q-ee learning is merely suitable for deterministic MDPs, and its convergent guarantee to derive an optimal policy has not been proved. In this paper, based on discussing different exploration methods, replacing the pre-action-selector in the Q-ee learning, we introduce a method that can be used to implement an active exploration to an environment, the Active Exploration Planning (AEP), into the learning system, which we call the Q-ae learning. With this replacement, the Q-ae learning not only maintains advantages of the Q-ee learning but also is adapted to a stochastic environment. Moreover, under deterministic MDPs, this paper presents the convergent condition and its proof for an agent to obtain the optimal policy by the method of the Q-ae learning. Further, by discussions and experiments, it is shown that by adjusting the relation between the learning factor and the discounted rate, the exploration process to an environment can be controlled on a stochastic environment. And, experimental results about the exploration rate to an environment and the correct rate of learned policies also illustrate the efficiency of the Q-ae learning on the stochastic environment.
Mitsuo USUI Nobuo SATO Akira OHKI Koji ENBUTSU Makoto HIKITA Michiyuki AMANO Kohsuke KATSURA Yasuhiro ANDO
Aiming at lower cost and further miniaturization, we developed a new optical coupling system for use as an optical interface of a parallel optical interconnect module, called ParaBIT-1. It consists of a new-structure 24-fiber bare fiber (BF) connector whose main parts are made of molded plastic and a 24-channel optical coupling component using new polymeric optical waveguide film. To prevent bare fibers from breaking, the BF connector plug has a fiber protector. This BF connector can be joined by direct physical contact between bare fibers in fiber guide holes with a 250-µm pitch. The buckling forces of the fibers themselves secure the physical contacts. The average measured insertion loss of the 24-fiber BF connector was 0.05 dB, and the return losses were over 35 dB. The optical coupling components are composed of a 24-ch polymeric optical waveguide film with 45 mirrors and the 24-fiber BF connector interface, and can be assembled by passive alignment. The high thermal stability of the film allows soldering, and the film is fabricated by direct photo patterning. The average insertion losses of the components for transmitter and receiver modules were 1.28 and 1.35 dB, respectively.
Masami HANE Takeo IKEZAWA Akio FURUKAWA
Silicon self-interstitial atom diffusion and implantation induced damage were studied by using molecular dynamics methods. The diffusion coefficient of interstitial silicon was calculated using molecular dynamics method based on the Stillinger-Weber potential. A comparison was made between the calculation method based on the Einstein relationship and the method based on a hopping analysis. For interstitial silicon diffusion, atomic site exchanges to the lattice atoms occur, and thus the total displacement-based calculation underestimates the ideal value of the diffusivity of the interstitial silicon. In addition with calculating the diffusion constant, we also identified its migration pathway and barrier energy in the case of Stillinger-Weber potential. Through a study of molecular dynamics calculation for the arsenic ion implantation process, it was found that the damage self-recovering process depends on the extent of damage. That is, damage caused by a single large impact easily disappears. In contrast, the damage leaves significant defects when two large impacts in succession cause an overlapped damage region.
Alexander BURENKOV Klaus TIETZEL Andreas HOSSINGER Jurgen LORENZ Heiner RYSSEL Siegfried SELBERHERR
The high accuracy which is necessary for modern process simulation often requires the use of Monte-Carlo ion implantation simulation methods with the disadvantage of very long simulation times especially for three-dimensional applications. In this work a new method for an accurate and CPU time efficient three-dimensional simulation of ion implantation is suggested. The approach is based on a combination of the algorithmic capabilities of a fast analytical and the Monte-Carlo simulation method.
We consider the problem of placing resources in a distributed computing system so that certain performance requirements may be met while minimizing the number of resource copies needed. Resources include special I/O processors, expensive peripheral devices, or such software modules as compilers, library routines, and data files. Due to the delay in accessing each of these resources, system performance degrades as the distance between each processor and its nearest resource copy increases. Thus, every processor must be within a given distance k1 of at least one resource copy, which is called the k-bounded placement problem. The structure of a distributed computing system is represented by a graph. The k-bounded placement problem is first transformed into the problem of finding smallest k-dominating sets in a graph. Searching for smallest k-dominating sets is formulated as a state-space search problem. We derive heuristic information to speed up the search, which is then used to solve the problem with the well-known A* algorithm. An illustrative example and some experimental results are presented to demonstrate the effectiveness of the heuristic search.
Layered Multicomposites by Sequential Adsorption (LAMSA) is layer by layer approach for ultrathin film fabrication that has been applied to a variety of organic and inorganic materials. In this paper, we present our objectives and work on the fabrication and modification of display devices and sensors primarily using LAMSA techniques. The term supramolecular layer assembly denotes the selective incorporation of processing techniques, layer configuration and molecular ordering that is achieved within planar devices. The first application involves modifying a polymer light emitting diode (PLED) device fabricated using the ITO/MEH-PPV/Ca protocol with ultrathin polyaniline derivatives. The second example involves photoinduced alignment in a hybrid LC cell configuration using polarized light with azo dye/polyelectrolyte ultrathin films. A supramolecular concept on substrates for opto- bioelectronic sensor configurations is described.
Node placement optimization in ShuffleNets is a combinatorial optimization problem. In this paper, a new heuristic node placement algorithm, called Lookahead Algorithm, is proposed. Its performance is compared with the lower bounds derived in [1], as well as some existing algorithms in the literature. Significant reduction in weighted mean hop distance hd is obtained, especially when the traffic distribution in ShuffleNets is highly skewed. Consider a ShuffleNet with 8 nodes, the hd obtained using Lookahead Algorithm is only 1.90% above the lower bound under the skewed traffic distribution (with traffic skew factor γ = 100), and 16.04% under uniform random traffic distribution.
Since for recognition tasks it is known that planar invariants are more easily obtained than others, decomposing a scene in terms of planar parts becomes very interresting. This paper presents a new approach to find the projections of planar surfaces in a pair of images. For this task we introduce the facet concept defined by linked edges (chains) and corners. We use collineations as projective information to match and verify their planarity. Our contribution consists in obtaining from an uncalibrated stereo pair of images a match of "planar" chains based on matched corners. Collineations are constrained by the fundamental matrix information and a Kalman filter approach is used to refine its computation.
Masaki MATSUSHITA Md. Abul KASHEM Shinzo MORITA
Thin films of carbon (C)-sulfur (S) compound were formed by plasma CVD (PCVD) at the special chemical condition. The reactor has a parallel plate electrode system and was operated at a discharge frequency of 13.56 MHz with using a mixture gas of argon (Ar), methane (CH4) and SF6. The deposition was performed on a substrate placed on the grounded electrode. Atomic composition of the film was observed to depend on the gas mixture ratio. The sulfur atom density was increased up to 30% with using a mixture gas at a pressure of 0.1 Torr and at a flow rate of 20, 20 and 50 SCCM for Ar, CH4 and SF6, respectively. It was expected that the C-S compounds were deposited under the condition of F atom elimination by forming HF.