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781-800hit(1110hit)

  • Rail-to-Rail OTA Based on Signal Decomposition

    Nobukazu TAKAI  Shigetaka TAKAGI  Nobuo FUJII  

     
    PAPER

      Vol:
    E88-A No:2
      Page(s):
    424-430

    This paper proposes a rail-to-rail OTA. By adding a signal decomposing circuit at the input of given OTAs that have a limited input voltage range, a rail-to-rail OTA is obtained. Each decomposed input voltage signal is converted to a current signal by an OTA and each output current of OTAs is summed to obtain a linear output signal. Since the input signal is decomposed into small magnitude voltage signals, the OTAs used to the voltage-current conversion do not require a wide input-range and any OTA can be used to realize a rail-to-rail input voltage range OTA. HSPICE simulations are performed to verify the validity of the proposed method.

  • Invariant Range Image Multi-Pose Face Recognition Using Gradient Face, Membership Matching Score and 3-Layer Matching Search

    Seri PANSANG  Boonwat ATTACHOO  Chom KIMPAN  Makoto SATO  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E88-D No:2
      Page(s):
    268-277

    The purpose of this paper is to present the novel technique to solve the recognition errors in invariant range image multi-pose face recognition. The scale, center and pose error problems were solved by using the geometric transform. Range image face data (RIFD) was obtained from a laser range finder and was used in the model to generate multi-poses. Each pose data size was reduced by linear reduction. The reduced RIFD was transformed to the gradient face model for facial feature image extraction and also for matching using the Membership Matching Score model. Using this method, the results from the experiment are acceptable although the size of gradient face image data is quite small (659 elements). Three-Layer Matching Search was the algorithm designed to reduce the access timing to the most accurate and similar pose position. The proposed algorithm was tested using facial range images from 130 people with normal facial expressions and without eyeglasses. The results achieved the mean success rate of 95.67 percent of 12 degrees up/down and left/right (UDLR) and 88.35 percent of 24 degrees UDLR.

  • Progressive Spectral Rendering Using Wavelet Decomposition

    Jin-Ren CHERN  Chung-Ming WANG  

     
    LETTER-Computer Graphics

      Vol:
    E88-D No:2
      Page(s):
    341-345

    We propose a novel approach based on wavelet decomposition for progressive full spectral rendering. In the fourth progressive stage, our method renders an image that is 95% similar to the final non-progressive approach but requires less than 70% of the execution time. The quality of the rendered image is visually plausible that is indistinguishable from that of the non-progressive method. Our approach is graceful, efficient, progressive, and flexible for full spectral rendering.

  • Design of Multiple U-Shaped Slot Microstrip Patch Antenna in 5 GHz Band WLAN

    Jeong-Min JU  Gyey-Teak JEONG  Joong-Han YOON  Cheol-Soon KIM  Hyung-Sup KIM  Kyung-Sup KWAK  

     
    LETTER-Terrestrial Radio Communications

      Vol:
    E88-B No:2
      Page(s):
    821-825

    In this study, a multiple U-shaped slot microstrip patch antenna for application to the 5 GHz band is designed and fabricated. To obtain sufficient bandwidth in the operating band, foam is inserted between the substrate and ground plane, the type of form is styrofoam, the coaxial probe source is used, and the position of the probe shift is adjusted from the center to the left. The measured result (5.02-5.955 GHz) of the fabricated antenna satisfies the conditions of VSWR < 2.0 in 5 GHz band (5.15-5.35 GHz, 5.47-5.725 GHz, 5.725-5.825 GHz), gain of 3.88-9.28 dBi, and broad radiation pattern.

  • Balanced Quatrefoil Decomposition of Complete Multigraphs

    Kazuhiko USHIO  Hideaki FUJIMOTO  

     
    PAPER

      Vol:
    E88-D No:1
      Page(s):
    17-22

    We show that the necessary and sufficient condition for the existence of a balanced quatrefoil decomposition of the complete multigraph λKn is n 9 and λ(n - 1) 0 (mod 24). Decomposition algorithms are also given.

  • Likelihood Function for QRM-MLD Suitable for Soft-Decision Turbo Decoding and Its Performance for OFCDM MIMO Multiplexing in Multipath Fading Channel

    Hiroyuki KAWAI  Kenichi HIGUCHI  Noriyuki MAEDA  Mamoru SAWAHASHI  Takumi ITO  Yoshikazu KAKURA  Akihisa USHIROKAWA  Hiroyuki SEKI  

     
    PAPER-MIMO

      Vol:
    E88-B No:1
      Page(s):
    47-57

    This paper proposes likelihood function generation of complexity-reduced Maximum Likelihood Detection with QR Decomposition and M-algorithm (QRM-MLD) suitable for soft-decision Turbo decoding and investigates the throughput performance using QRM-MLD with the proposed likelihood function in multipath Rayleigh fading channels for Orthogonal Frequency and Code Division Multiplexing (OFCDM) multiple-input multiple-output (MIMO) multiplexing. Simulation results show that by using the proposed likelihood function generation scheme for soft-decision Turbo decoding following QRM-MLD in 4-by-4 MIMO multiplexing, the required average received signal energy per bit-to-noise power spectrum density ratio (Eb/N0) at the average block error rate (BLER) of 10-2 at a 1-Gbps data rate is significantly reduced compared to that using hard-decision decoding in OFCDM access with 16 QAM modulation, the coding rate of 8/9, and 8-code multiplexing with a spreading factor of 8 assuming a 100-MHz bandwidth. Furthermore, we show that by employing QRM-MLD associated with soft-decision Turbo decoding for 4-by-4 MIMO multiplexing, the throughput values of 500 Mbps and 1 Gbps are achieved at the average received Eb/N0 of approximately 4.5 and 9.3 dB by QPSK with the coding rate of R = 8/9 and 16QAM with R = 8/9, respectively, for OFCDM access assuming a 100-MHz bandwidth in a twelve-path Rayleigh fading channel.

  • The Effect Air-Intake Format of Equipment Gives to Air Conditioning System in a Data Center

    Yuki FURIHATA  Hirofumi HAYAMA  Masamichi ENAI  Taro MORI  

     
    PAPER-Cooling for Communications

      Vol:
    E87-B No:12
      Page(s):
    3568-3575

    The effects of air-intake format of forced-air-cooled equipment on the efficiency of air conditioning systems are studied. A modern data center features a large number of information-processing devices to provide telecommunication services. These devices generate considerable heat, and the equipment that houses these devices often employs "forced air cooling" in which a cooling effect is achieved by sucking in large amounts of room air. An air conditioning system used for a machine room filled with such equipment therefore requires high fan driving power resulting in significantly low air conditioning efficiency. In this study, we first performed mockup-based experiments to obtain a quantitative understanding of how different air-intake formats for equipment affect the temperature at various room locations such as equipment intake. We then created a model for predicting the temperature at various locations, and on the basis of this model, we analyzed the factors affecting intake temperature and examined how intake temperature affects air conditioning efficiency. It was found that placing air inlets in the lower 1/3 portion of forced-air-cooled equipment could prevent the equipment from reabsorbing the hot air that it blows out and therefore improve air conditioning efficiency.

  • Crosstalk Noise Optimization by Post-Layout Transistor Sizing

    Masanori HASHIMOTO  Hidetoshi ONODERA  

     
    PAPER-Physical Design

      Vol:
    E87-A No:12
      Page(s):
    3251-3257

    This paper proposes a post-layout transistor sizing method for crosstalk noise reduction. The proposed method downsizes the drivers of aggressor wires for noise reduction, utilizing the precise interconnect information extracted from the detail-routed layouts. We develop a transistor sizing algorithm for crosstalk noise reduction under delay constraints, and construct a crosstalk noise optimization method utilizing an analytic crosstalk noise model and a transistor sizing framework that have been developed. Our method exploits the transistor sizing framework that can vary transistor widths inside cells with interconnects unchanged. Our optimization method therefore never causes a new crosstalk noise problem, and does not need iterative layout optimization. The effectiveness of the proposed method is experimentally examined using 2 circuits. The maximum noise voltage is reduced by more than 50% without delay violation. These results show that the risk of crosstalk noise problems can be considerably reduced after detail-routing.

  • A Practical Subspace Blind Identification Algorithm with Reduced Computational Complexity

    Nari TANABE  Toshihiro FURUKAWA  Kohichi SAKANIWA  Shigeo TSUJII  

     
    PAPER-Digital Signal Processing

      Vol:
    E87-A No:12
      Page(s):
    3360-3371

    We propose a practical blind channel identification algorithm based on the principal component analysis. The algorithm estimates (1) the channel order, (2) the noise variance, and then identifies (3) the channel impulse response, from the autocorrelation of the channel output signal without using the eigenvalue and singular-value decomposition. The special features of the proposed algorithm are (1) practical method to find the channel order and (2) reduction of computational complexity. Numerical examples show the effectiveness of the proposed algorithm.

  • Vapor Deposition of Polyurethane Thin Film Having Bis (Hydroxyquinoline) Zinc Complex for Organic LED

    Xiaodong WANG  Kenji OGINO  Kuniaki TANAKA  Hiroaki USUI  

     
    LETTER-Characterization of Organic Devices

      Vol:
    E87-C No:12
      Page(s):
    2122-2124

    Thin film of polyurethane having metal complex was prepared by vapor deposition polymerization of bis (5,8-dihydroxyquinoline) zinc (ZnHq2) and 4, 4'-diphenylmethane diisocyanate monomers. The film was applied for the electron-transporting emissive layer of the organic light emitting diode. The deposition-polymerized film was found to give higher quantum efficiency of luminescence than the ZnHq2 monomer film.

  • A Phase Compensation Algorithm for High-Resolution Pulse Radar Systems

    Takuya SAKAMOTO  Toru SATO  

     
    PAPER-Sensing

      Vol:
    E87-B No:11
      Page(s):
    3314-3321

    Imaging techniques for robots are important and meaningful in the near future. Pulse radar systems have a great potential for shape estimation and locationing of targets. They have an advantage that they can be used even in critical situations where optical techniques cannot be used. It is thus required to develop high-resolution imaging algorithms for pulse radar systems. High-resolution imaging algorithms utilize the carrier phase of received signals. However, their estimation accuracy suffers degradation due to phase rotation of the received signal because the phase depends on the shape of the target. In this paper, we propose a phase compensation algorithm for high-resolution pulse radar systems. The proposed algorithm works well with SEABED algorithm, which is a non-parametric algorithm of estimating target shapes based on a reversible transform. The theory is presented first and numerical simulation results follow. We show the estimation accuracy is remarkably improved without sacrificing the resolution using the proposed algorithm.

  • Real-Time Measurement of a Viewer's Position to Evaluate a Stereoscopic LED Display with a Parallax Barrier

    Shinya MATSUMOTO  Hirotsugu YAMAMOTO  Yoshio HAYASAKI  Nobuo NISHIDA  

     
    PAPER

      Vol:
    E87-C No:11
      Page(s):
    1982-1988

    Our goal is to realize an extra-large stereoscopic display in the open air for use by the general public. We have developed a stereoscopic large display by use of a full-color LED panel. Although the developed display enables viewers to view the stereoscopic images without any special glasses, it is necessary for the viewers to move to stand within the viewing areas. Movements of the viewers are considered to depend on arrangements of viewing areas. The purpose of this paper is to investigate the movements of viewers who watch different designs of stereoscopic LED displays with a parallax barrier, including conventional designs to provide multiple perspective images and designs to eliminate pseudoscopic viewing areas, and evaluate the performance of different viewing areas based on the obtained paths of the viewers. We have developed a real-time measurement system of a viewer's position by use of a camera on the ceiling. We have recorded the viewing movements caused by the shift of viewing areas. It was found that the viewers moved to stand on orthoscopic viewing positions. The movements of viewers who move to find a viewing area have been recorded with different designs of stereoscopic LED displays that provide different viewing areas. We have calculated the lateral moving time of the viewers'movements. It is shown that the elimination of pseudoscopic viewing areas reduces the lateral moving time. Thus, the real-time measurement system of a viewer's position has been utilized for evaluation of performance of the different designs of stereoscopic LED displays.

  • Formal Detection of Three Automation Surprises in Human-Machine Interaction

    Yoshitaka UKAWA  Toshimitsu USHIO  Masakazu ADACHI  Shigemasa TAKAI  

     
    PAPER-Concurrent Systems

      Vol:
    E87-A No:11
      Page(s):
    2878-2884

    In this paper, we propose a formal method for detection of three automation surprises in human-machine interaction; a mode confusion, a refusal state, and a blocking state. The mode confusion arises when a machine is in a different mode from that anticipated by the user, and is the most famous automation surprise. The refusal state is a situation that the machine does not respond to a command the user executes. The blocking state is a situation where an internal event occurs, leading to change of an interface the user does not know. In order to detect these phenomena, we propose a composite model in which a machine and a user model evolve concurrently. We show that the detection of these phenomena in human-machine interaction can be reduced to a reachability problem in the composite model.

  • Information-Theoretically Secure Key Insulated Encryption: Models, Bounds and Constructions

    Yumiko HANAOKA  Goichiro HANAOKA  Junji SHIKATA  Hideki IMAI  

     
    PAPER-Cryptography and Information Security

      Vol:
    E87-A No:10
      Page(s):
    2521-2532

    Computer systems are constantly under attack and illegal access is a constant threat which makes security even more critical. A system can be broken into and secret information, e.g. decryption key, may be exposed, resulting in a total break of the system. Recently, a new framework for the protection against such key exposure problem was suggested and was called, Key-Insulated Encryption (KIE). In our paper, we introduce a novel approach to key insulated cryptosystems that offers provable security without computational assumptions. For the model of Information-Theoretically Secure Key-Insulated Encryption (ISKIE), we show lower bounds on required memory sizes of user, trusted device and sender. Our bounds are all tight as our concrete construction of ISKIE achieves all the bounds. We also extend this concept further by adding an extra property so that any pair of users in the system is able to communicate with each other and still have the same security benefits as the existing KIE based on intractability assumptions. We called this, Dynamic and Mutual Key-Insulated Encryption (DMKIE), and concrete implementations of DMKIE will be shown as well. In the end, we discuss the relationship of DMKIE against Key Predistribution Schemes (KPS) and Broadcast Encryption Schemes (BES), that is, we show that DMKIE can be constructed from either KPS or BES.

  • Pulse Position Controlled DS-UWB

    Yukitoshi SANADA  

     
    LETTER

      Vol:
    E87-A No:10
      Page(s):
    2716-2718

    In this paper, a novel UWB system called pulse position controlled UWB is proposed. One of the problems in UWB systems is the restriction of data rates due to multipath. The proposed UWB system shorten the pulse interval adaptively depending on channel characteristics. It has been shown that the proposed UWB system can increase the data rate with about 30% and improve the BER at the same time.

  • Overlapping PPM Fiber-Optic CDMA Systems with Imperfect Code Synchronization

    Anh T. PHAM  Hiroyuki YASHIMA  

     
    LETTER-Spread Spectrum Thchnologies and Applications

      Vol:
    E87-A No:10
      Page(s):
    2581-2584

    This paper theoretically evaluates the performance of overlapping pulse-position modulation (OPPM) fiber-optic code-division multiple-access (FO-CDMA) systems in the presence of code synchronization errors. The analysis is carried out with a constraint on throughput-pulsewidth product. Discussions on effects of various system parameters, such as timing offset, index of overlap, number of users, are presented. The results show that the OPPM FO-CDMA systems with high index of overlaps have better resistance against imperfect synchronization. In fact, the acceptable performance could be maintained even with timing offsets of up to 30% of chip pulsewidth. On the other hand, strict code synchronization is necessarily required, preferably within a half code chip pulsewidth.

  • Virtual 3D Gearbox Widget Technique for Precise Adjustment by Hand Motion in Immersive VR

    Noritaka OSAWA  Xiangshi REN  

     
    PAPER-Multimedia Pattern Processing

      Vol:
    E87-D No:10
      Page(s):
    2408-2414

    Direct manipulation by hand is an intuitive and simple way of positioning objects in an immersive virtual environment. However, this technique is not suitable for making precise adjustments to virtual objects in an immersive environment because it is difficult to hold a hand unsupported in midair and to then release an object at a fixed point. We therefore propose an alternative technique using a virtual 3D gearbox widget that we have designed, which enables users to adjust values precisely. We tested the technique in a usability study along with the use of hand manipulation and a slider. The results showed that the gearbox was the best of the three techniques for precise adjustment of small targets, in terms of both performance data and subject preference.

  • Balanced Bowtie Decomposition of Symmetric Complete Multi-digraphs

    Kazuhiko USHIO  Hideaki FUJIMOTO  

     
    PAPER-Graphs and Networks

      Vol:
    E87-A No:10
      Page(s):
    2769-2773

    We show that the necessary and sufficient condition for the existence of a balanced bowtie decomposition of the symmetric complete multi-digraph is n 5 and λ(n-1) 0 (mod 6). Decomposition algorithms are also given.

  • Subcarrier Clustering in Adaptive Array Antenna for OFDM Systems in the Presence of Co-channel Interference

    Hidehiro MATSUOKA  Yong SUN  

     
    PAPER-Wireless Network System Performances

      Vol:
    E87-C No:9
      Page(s):
    1477-1484

    For future high-speed wireless communications using orthogonal frequency division multiplexing (OFDM), two major system requirements will emerge: throughput improvement and rich interference elimination. Because of its broadband nature and limited frequency allocations worldwide, interference from co-located wireless LAN's operating in the same frequency band will become a serious deployment issue. Adaptive array antenna can enhance the performance by suppressing the co-channel interference even when interference may have a large amount of multipath and also have similar received power to the desired signal. There are typically two types of adaptive array architecture for OFDM systems, whose signal processing is carried out before or after FFT (Fast Fourier Transform). In general, the pre-FFT array processing has low complexity, but in rich multipath and interference environments, the performance will deteriorate drastically. In contrast, the post-FFT array processing can provide the optimum performance even in such severe environments at the cost of complexity. Therefore, complexity-reduction techniques combined with the achievement of high system performance will be a key issue for adaptive array antenna applications. This paper proposes novel adaptive array architecture, which is a complexity-reduction technique using subcarrier clustering for post-FFT adaptive array. In the proposed scheme, plural subcarriers can be clustered into a group with the same spatial weight. Simulation results show that the proposed architecture is a promising candidate for real implementation, since it can achieve high performance with much lower complexity even in a rich multipath environment with low signal to noise plus interference ratio (SNIR).

  • Quantization Noise Reduction for DCT Coded Images

    Ching-Chih KUO  Wen-Thong CHANG  

     
    PAPER-Multimedia Systems

      Vol:
    E87-B No:8
      Page(s):
    2342-2351

    By modelling the quantization error as additive white noise in the transform domain, Wiener filter is used to reduce quantization noise for DCT coded images in DCT domain. Instead of deriving the spectrum of the transform coefficient, a DPCM loop is used to whiten the quantized DCT coefficients. The DPCM loop predicts the mean for each coefficient. By subtracting the mean, the quantized DCT coefficient is converted into the sum of prediction error and quantization noise. After the DPCM loop, the prediction error can be assumed uncorrelated to make the design of the subsequent Wiener filter easy. The Wiener filter is applied to remove the quantization noise to restore the prediction error. The original coefficient is reconstructed by adding the DPCM predicted mean with the restored prediction error. To increase the prediction accuracy, the decimated DCT coefficients in each subband are interpolated from the overlapped blocks.

781-800hit(1110hit)