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7861-7880hit(21534hit)

  • Accuracy of Smooth Pursuit Eye Movement and Perception Rate of a False Contour While Pursuing a Rapidly Moving Image

    Yusuke HORIE  Yuta KAWAMURA  Akiyuki SEITA  Mitsuho YAMADA  

     
    LETTER-Vision

      Vol:
    E94-A No:2
      Page(s):
    542-547

    The purpose of this study was to clarify whether viewers can perceive a digitally deteriorated image while pursuing a speedily moving digitally compressed image. We studied the perception characteristics of false contours among the various digital deteriorations for the four types of displays i.e. CRT, PDP, EL, LCD by changing the gradation levels and the speed of moving image as parameters. It is known that 8 bits is not high enough resolution for still images, and it is assumed that 8 bits is also not enough for an image moving at less than 5 deg/sec since the tracking accuracy of smooth pursuit eye movement (SPEM) is very high for a target moving at less than 5 deg/sec. Given these facts, we focused on images moving at more than 5 deg/sec. In our results, the images deteriorated by a false contour at a gradation level less than 32 were perceived by every subject at almost all velocities, from 5 degrees/sec to 30 degrees/sec, for all four types of displays we used. However, the perception rate drastically decreased when the gradation levels reached 64, with almost no subjects detecting deterioration for gradation levels more than 64 at any velocity. Compared to other displays, LCDs yielded relatively high recognition rates for gradation levels of 64, especially at lower velocities.

  • Design of a Broadband Cruciform Substrate Integrated Waveguide Coupler

    Mitsuyoshi KISHIHARA  Isao OHTA  Kensuke OKUBO  

     
    LETTER-Microwaves, Millimeter-Waves

      Vol:
    E94-C No:2
      Page(s):
    248-250

    A broadband cruciform substrate integrated waveguide coupler is designed based on the planar circuit approach. The broadband property is obtained by widening the crossed region in the same way as rectangular waveguide cruciform couplers. As a result, a 3 dB coupler with fractional bandwidth of 30% is realized at 24 GHz.

  • Post-Routing Double-Via Insertion for X-Architecture Clock Tree Yield Improvement

    Chia-Chun TSAI  Chung-Chieh KUO  Trong-Yen LEE  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E94-A No:2
      Page(s):
    706-716

    As the VLSI manufacturing technology shrinks to 65 nm and below, reducing the yield loss induced by via failures is a critical issue in design for manufacturability (DFM). Semiconductor foundries highly recommend using the double-via insertion (DVI) method to improve yield and reliability of designs. This work applies the DVI method in the post-stage of an X-architecture clock routing for double-via insertion rate improvement. The proposed DVI-X algorithm constructs the bipartite graphs of the partitioned clock routing layout with single vias and redundant-via candidates (RVCs). Then, DVI-X applies the augmenting path approach associated with the construction of the maximal cliques to obtain the matching solution from the bipartite graphs. Experimental results on benchmarks show that DVI-X can achieve higher double-via insertion rate by 3% and less running time by 68% than existing works. Moreover, a skew tuning technique is further applied to achieve zero skew because the inserted double vias affect the clock skew.

  • Design and Modeling of a High Efficiency Step-Up/Step-Down DC-DC Converter with Smooth Transition

    Yanzhao MA  Hongyi WANG  Guican CHEN  

     
    PAPER

      Vol:
    E94-A No:2
      Page(s):
    646-652

    This paper presents a step-up/step-down DC-DC converter with three operation modes to achieve high efficiency and small output ripple voltage. A constant time buck-boost mode, which is inserted between buck mode and boost mode, is proposed to achieve smooth transition. With the proposed mode, the output ripple voltage is significantly reduced when the input voltage is approximate to the output voltage. Besides, the novel control scheme minimizes the conduction loss by reducing the average inductor current and the switching loss by making the converter operate like a buck or boost converter. The small signal model of the step-up/step-down DC-DC converter is also derived to guide the compensation network design. The step-up/step-down converter is designed with a 0.5 µm CMOS n-well process, and can regulate an output voltage within the input voltage ranged from 2.5 V to 5.5 V with a maximum power efficiency of 96%. The simulation results show that the proposed converter exhibits an output ripple voltage of 28 mV in the transition mode.

  • A Design Procedure for CMOS Three-Stage NMC Amplifiers

    Mohammad YAVARI  

     
    PAPER

      Vol:
    E94-A No:2
      Page(s):
    639-645

    This paper presents a novel time-domain design procedure for fast-settling three-stage nested-Miller compensated (NMC) amplifiers. In the proposed design methodology, the amplifier is designed to settle within a definite time period with a given settling accuracy by optimizing both the power consumption and silicon die area. Detailed design equations are presented and the circuit level simulation results are provided to verify the usefulness of the proposed design procedure with respect to the previously reported design schemes.

  • A Robust Detection in the Presence of Clutter and Jammer Signals with Unknown Powers

    Victor GOLIKOV  Olga LEBEDEVA  

     
    LETTER-Digital Signal Processing

      Vol:
    E94-A No:2
      Page(s):
    817-822

    This work extends the constant false alarm rate (CFAR) detection methodology to detection in the presence of two independent interference sources with unknown powers. The proposed detector is analyzed on the assumption that clutter and jammer covariance structures are known and have relatively low rank properties. The limited-dimensional subspace-based approach leads to a robust false alarm rate (RFAR) detector. The RFAR detection algorithm is developed by an adaptation and extension of Hotelling's principal-component method. The detector performance loss and false alarm stability loss to unknown clutter and jammer powers have been evaluated for example scenario.

  • A 2-GHz Gain Equalizer for Analog Signal Transmission Using Feedforward Compensation by a Low-Pass Filter

    Masayoshi TAKAHASHI  Keiichi YAMAMOTO  Norio CHUJO  Ritsurou ORIHASHI  

     
    PAPER

      Vol:
    E94-A No:2
      Page(s):
    611-616

    A 2 GHz gain equalizer for analog signal transmission using a novel gain compensation method is described in this paper. This method is based on feedforward compensation by a low-pass filter, which improves the gain-equalizing performance by subtracting low-pass filtered signals from the directly passed signal at the end of a transmission line. The advantage of the proposed method over the conventional one is that the gain is equalized with a smaller THD at higher frequencies by using a low-pass instead of a high-pass filter. In this circuit, the peak gain is adjustable from 0 to 2.4 dB and the frequency of the peak gain can be controlled up to 2 GHz by varying the value of an external capacitor. Also this circuit achieves THD with 5 dB better than the conventional circuits.

  • Estimation of Blood Pressure Measurements for Hypertension Diagnosis Using Oscillometric Method

    Youngsuk SHIN  

     
    PAPER-Neural Networks and Bioengineering

      Vol:
    E94-A No:2
      Page(s):
    806-812

    Blood pressure is the measurement of the force exerted by blood against the walls of the arteries. Hypertension is a major risk factor of cardiovascular diseases. The systolic and diastolic blood pressures obtained from the oscillometric method could carry clues about hypertension. However, blood pressure is influenced by individual traits such as physiology, the geometry of the heart, body figure, gender and age. Therefore, consideration of individual traits is a requisite for reliable hypertension monitoring. The oscillation waveforms extracted from the cuff pressure reflect individual traits in terms of oscillation patterns that vary in size and amplitude over time. Thus, uniform features for individual traits from the oscillation patterns were extracted, and they were applied to evaluate systolic and diastolic blood pressures using two feedforward neural networks. The measurements of systolic and diastolic blood pressures from two neural networks were compared with the average values of systolic and diastolic blood pressures obtained by two nurses using the auscultatory method. The recognition performance was based on the difference between the blood pressures measured by the auscultation method and the proposed method with two neural networks. The recognition performance for systolic blood pressure was found to be 98.2% for 20 mmHg, 93.5% for 15 mmHg, and 82.3% for 10 mmHg, based on maximum negative amplitude. The recognition performance for diastolic blood pressure was found to be 100% for 20 mmHg, 98.8% for 15 mmHg, and 88.2% for 10 mmHg based on maximum positive amplitude. In our results, systolic blood pressure showed more fluctuation than diastolic blood pressure in terms of individual traits, and subjects with prehypertension or hypertension (systolic blood pressure) showed a stronger steep-slope pattern in 1/3 section of the feature windows than normal subjects. The other side, subjects with prehypertension or hypertension (diastolic blood pressure) showed a steep-slope pattern in front of the feature windows (2/3 section) than normal subjects. This paper presented a novel blood pressure measurement system that can monitor hypertension using personalized traits. Our study can serve as a foundation for reliable hypertension diagnosis and management based on consideration of individual traits.

  • Convergence Property of IDR(s) Method Implemented along with Method of Moments for Solving Large-Scale Electromagnetic Scattering Problems Involving Conducting Objects

    Hidetoshi CHIBA  Toru FUKASAWA  Hiroaki MIYASHITA  Yoshihiko KONISHI  

     
    PAPER-Electromagnetic Theory

      Vol:
    E94-C No:2
      Page(s):
    198-205

    In this paper, the performance of the induced dimension reduction (IDR) method implemented along with the method of moments (MoM) is described. The MoM is based on a combined field integral equation for solving large-scale electromagnetic scattering problems involving conducting objects. The IDR method is one of Krylov subspace methods. This method was initially developed by Peter Sonneveld in 1979; it was subsequently generalized to the IDR(s) method. The method has recently attracted considerable attention in the field of computational physics. However, the performance of the IDR(s) has hardly been studied or practiced for electromagnetic wave problems. In this study, the performance of the IDR(s) is investigated and clarified by comparing the convergence property and memory requirement of the IDR(s) with those of other representative Krylov solvers such as biconjugate gradient (BiCG) methods and generalized minimal residual algorithm (GMRES). Numerical experiments reveal that the characteristics of the IDR(s) against the parameter s strongly depend on the geometry of the problem; in a problem with a complex geometry, s should be set to an adequately small value in order to avoid the "spurious convergence" which is a problem that the IDR(s) inherently holds. As for the convergence behavior, we observe that the IDR(s) has a better convergence ability than GPBiCG and GMRES(m) in a variety of problems with different complexities. Furthermore, we also confirm the IDR(s)'s inherent advantage in terms of the memory requirements over GMRES(m).

  • A Dynamic Geometry Reconstruction Technique for Mobile Devices Using Adaptive Checkerboard Recognition and Epipolar Geometry

    Vinh Ninh DAO  Masanori SUGIMOTO  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E94-D No:2
      Page(s):
    336-348

    This paper describes a technique for reconstructing dynamic scene geometry using a handheld video projector-camera system and a single checkerboard image as a structured light pattern. The proposed technique automatically recognizes a dense checkerboard pattern under dynamic conditions. The pattern-recognition process is adaptive to different light conditions and an object's color, thereby avoiding the need to set threshold values manually for different objects when the scanning device is moving. We also propose a technique to find corresponding positions for the checkerboard pattern, when displayed by a projector, without needing any position-encoding techniques. The correspondence matching process is based on epipolar geometry, enabling the checkerboard pattern to be matched even if parts of it are occluded. By using a dense checkerboard pattern, we can construct a handheld projector-camera system that can acquire the geometry of objects in real time, and we have verified the feasibility of the proposed techniques.

  • A General Reverse Converter Architecture with Low Complexity and High Performance

    Keivan NAVI  Mohammad ESMAEILDOUST  Amir SABBAGH MOLAHOSSEINI  

     
    PAPER-Computer System

      Vol:
    E94-D No:2
      Page(s):
    264-273

    This paper presents a general architecture for designing efficient reverse converters based on the moduli set {2α, 22β+1-1, 2β-1}, where β < α ≤ 2β, by using a parallel implementation of mixed-radix conversion (MRC) algorithm. The moduli set {2α, 22β+1-1, 2β-1} is free from modulo (2k+1)-type which can result in an efficient arithmetic unit for residue number system (RNS). The values of α and β can be selected to provide the required dynamic range (DR) and also to adjust the desired equilibrium between moduli bit-width. The simple multiplicative inverses of the proposed moduli set and also using novel techniques to simplify conversion equations lead to a low-complexity and high-performance general reverse converter architecture that can be used to support different DRs. Moreover, due to the current importance of the 5n-bit DR moduli sets, we also introduced the moduli set {22n, 22n+1-1, 2n-1} which is a special case of the general set {2α, 22β+1-1, 2β-1}, where α=2n and β=n. The converter for this special set is derived from the presented general architecture with higher speed than the fastest state-of-the-art reverse converter which has been designed for the 5n-bit DR moduli set {22n, 22n+1-1, 2n-1}. Furthermore, theoretical and FPGA implementation results show that the proposed reverse converter for moduli set {22n, 22n+1-1, 2n-1} results in considerable improvement in conversion delay with less hardware requirements compared to other works with similar DR.

  • Probing of Maxwell-Wagner Type Interfacial Charging Process in Double-Layer Devices by Time-Resolved Second Harmonic Generation

    Le ZHANG  Dai TAGUCHI  Jun LI  Takaaki MANAKA  Mitsumasa IWAMOTO  

     
    PAPER

      Vol:
    E94-C No:2
      Page(s):
    141-145

    The Maxwell-Wagner type interfacial charging processes were characterized by time-resolved second harmonic generation method (TR-SHG) using three typical organic double-layer devices, i.e., IZO/α-NPD/Alq3/Al for OLED and ITO/PI/α-NPD (or pentacene)/Au for MIM elements. Devices with a PI blocking layer represent one-carrier transport case, while the OLED is a typical two-carrier transport device. It is found that three devices show similar behavior of charging of the electrodes, however, interfacial charging behavior was different from case to case. On the basis of Maxwell-Wagner model, the different transients were analyzed with consideration of carrier species responsible for the interfacial charging. The observed TR-SHG well support the results of I-V measurements.

  • A Low-Noise and Highly-Linear Transmitter with Envelope Injection Pre-Power Amplifier for Multi-Mode Radio

    Shouhei KOUSAI  Daisuke MIYASHITA  Junji WADATSUMI  Rui ITO  Takahiro SEKIGUCHI  Mototsugu HAMADA  Kenichi OKADA  

     
    PAPER

      Vol:
    E94-A No:2
      Page(s):
    592-602

    A wideband, low noise, and highly linear transmitter for multi-mode radio is presented. Envelope injection scheme with a CMOS amplifier is developed to obtain sufficient linearity for complex modulation schemes such as OFDM, and to achieve low noise for concurrent operation of more than one standard. Active matching technique with doubly terminated LPF topology is also presented to realize wide bandwidth, low power consumption, and to eliminate off-chip components without increasing die area. A multi-mode transmitter is implemented in a 0.13 µm CMOS technology with an active area of 1.13 mm2. Third-order intermodulation product is improved by 17 dB at -3 dBm output by the envelope injection scheme. The transmitter achieves EVM of less than -29.5 dB at -3 dBm output from 0.2 to 7.2 GHz while consuming only 69 mW. The transmitter is also tested with multiple standards of UMTS, 802.11b, WiMax, 802.11a, and 802.11n, and satisfies EVM, ACLR, and spectrum specifications.

  • Ordinal Optimization Approach for Throughput Maximization Problems in MOFDM Uplink System

    Jung-Shou HUANG  Shieh-Shing LIN  Shih-Cheng HORNG  

     
    LETTER-Mobile Information Network and Personal Communications

      Vol:
    E94-A No:2
      Page(s):
    879-883

    This work presents a two-stage ordinal optimization theory-based approach for solving the throughput maximization problems with power constraints of sub-carrier assignment and power allocation in multi-user orthogonal frequency division multiplexing uplink systems. In the first stage, a crude but efficient model is employed to evaluate the performance of a sub-carrier assignment pattern and the genetic algorithm is used to search through the huge solution space. In the second stage, an exact model is employed to evaluate s best sub-carrier assignment patterns obtained in stage 1 and form the select subset. Finally, the best one of the select subset is the good enough solution that we seek. Via numerous tests, this work demonstrates the efficiency of the proposed algorithm and compares it with those of other heuristic methods.

  • A New Method of 'Solid Inking' and Its Application to Direct Patterning of InAs Nanowire Using Dip-Pen Nanolithography

    Tong WANG  Yoshiki SHIMIZU  Naoyuki ISHIDA  Hirobumi USHIJIMA  

     
    PAPER

      Vol:
    E94-C No:2
      Page(s):
    146-150

    We report a new approach to creating a 'solid ink' and direct patterning of InAs nanowires on a Si substrate using dip-pen nanolithography (DPN). The normal method to prepare an 'ink' is a solution-based process using sonication to liquidize nanoparticles, which we call 'liquid ink' in this paper. As ink-solution-based DPN patterning has been prevalent in most studies, herein we propose a new method, 'solid inking', by which the inking process is solution-free. In our work, InAs nanowires were transferred to an AFM tip by directly scanning the tip over an InAs nanowire wafer at humidity over 80%. By this method, the preparation of ink and the 'inking' process is combined into one step, and a large amount of nanowires can be collected onto the tip to ensure the formation of a continuous ink flow for the direct patterning.

  • Trace Representation of Binary Generalized Cyclotomic Sequences with Length pm

    Xiaoni DU  Zhixiong CHEN  

     
    PAPER-Information Theory

      Vol:
    E94-A No:2
      Page(s):
    761-765

    Some new generalized cyclotomic sequences defined by C. Ding and T. Helleseth are proven to exhibit a number of good randomness properties. In this paper, we determine the defining pairs of these sequences of length pm (p prime, m ≥ 2) with order two, then from which we obtain their trace representation. Thus their linear complexity can be derived using Key's method.

  • Synthesis of 2-Channel IIR Paraunitary Filter Banks by Successive Extraction of 2-Port Lattice Sections

    Nagato UEDA  Eiji WATANABE  Akinori NISHIHARA  

     
    PAPER-Digital Signal Processing

      Vol:
    E94-A No:2
      Page(s):
    653-660

    This paper proposes a synthesis method of 2-channel IIR paraunitary filter banks by successive extraction of 2-port lattice sections. When a power symmetry transfer function is given, a filter bank is realized as cascade of paraunitary 2-port lattice sections. The method can synthesize both odd- and even-order filters with Butterworth or elliptic characteristics. The number of multiplications per second can also be reduced.

  • The Precoder Design for Intrablock MMSE Equalization and Block Delay Detection with a Modified Oblique Projection Framework

    Chun-Hsien WU  

     
    LETTER-Digital Signal Processing

      Vol:
    E94-A No:2
      Page(s):
    829-832

    This letter presents a method to enable the precoder design for intrablock MMSE equalization with previously proposed oblique projection framework. The joint design of the linear transceiver with optimum block delay detection is built. Simulation results validate the proposed approach and show the superior BER performance of the optimized transceiver.

  • Multi-Layer Dielectric Cavity Antennas with Extended Aperture Height

    Kook Joo LEE  Moonil KIM  Jung Aun LEE  Sanggeun JEON  

     
    LETTER-Antennas and Propagation

      Vol:
    E94-B No:2
      Page(s):
    573-575

    A dominant-mode rectangular cavity antenna design yielding an improved bandwidth is experimentally verified. Simple field theories indicate that extending the aperture height should increase the antenna bandwidth without shifting the operation frequency. Antenna samples built from a 4.4 dielectric constant material produce 3-dB efficiency bandwidths of 15 and 23 percent for the respective cavity height-to-width ratios of 0.5 and 0.75 at 7 GHz.

  • Pattern Recognition with Gaussian Mixture Models of Marginal Distributions Open Access

    Masako OMACHI  Shinichiro OMACHI  

     
    PAPER-Pattern Recognition

      Vol:
    E94-D No:2
      Page(s):
    317-324

    Precise estimation of data distribution with a small number of sample patterns is an important and challenging problem in the field of statistical pattern recognition. In this paper, we propose a novel method for estimating multimodal data distribution based on the Gaussian mixture model. In the proposed method, multiple random vectors are generated after classifying the elements of the feature vector into subsets so that there is no correlation between any pair of subsets. The Gaussian mixture model for each subset is then constructed independently. As a result, the constructed model is represented as the product of the Gaussian mixture models of marginal distributions. To make the classification of the elements effective, a graph cut technique is used for rearranging the elements of the feature vectors to gather elements with a high correlation into the same subset. The proposed method is applied to a character recognition problem that requires high-dimensional feature vectors. Experiments with a public handwritten digit database show that the proposed method improves the accuracy of classification. In addition, the effect of classifying the elements of the feature vectors is shown by visualizing the distribution.

7861-7880hit(21534hit)