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9581-9600hit(42807hit)

  • Experiments Validating the Effectiveness of Multi-Point Wireless Energy Transmission with Carrier Shift Diversity Open Access

    Daiki MAEHARA  Gia Khanh TRAN  Kei SAKAGUCHI  Kiyomichi ARAKI  Minoru FURUKAWA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E97-B No:9
      Page(s):
    1928-1937

    This paper presents a method to seamlessly extend the coverage of energy supply field for wireless sensor networks in order to free sensors from wires and batteries, where the multi-point scheme is employed to overcome path-loss attenuation, while the carrier shift diversity is introduced to mitigate the effect of interference between multiple wave sources. As we focus on the energy transmission part, sensor or communication schemes are out of scope of this paper. To verify the effectiveness of the proposed wireless energy transmission, this paper conducts indoor experiments in which we compare the power distribution and the coverage performance of different energy transmission schemes including conventional single-point, simple multi-point and our proposed multi-point scheme. To easily observe the effect of the standing-wave caused by multipath and interference between multiple wave sources, 3D measurements are performed in an empty room. The results of our experiments together with those of a simulation that assumes a similar antenna setting in free space environment show that the coverage of single-point and multi-point wireless energy transmission without carrier shift diversity are limited by path-loss, standing-wave created by multipath and interference between multiple wave sources. On the other hand, the proposed scheme can overcome power attenuation due to the path-loss as well as the effect of standing-wave created by multipath and interference between multiple wave sources.

  • Joint Tx/Rx MMSE Filtering for Single-Carrier MIMO Transmission

    Shinya KUMAGAI  Tatsunori OBARA  Tetsuya YAMAMOTO  Fumiyuki ADACHI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E97-B No:9
      Page(s):
    1967-1976

    In this paper, we propose a joint transmit and receive linear filtering based on minimum mean square error criterion (joint Tx/Rx MMSE filtering) for single-carrier (SC) multiple-input multiple-output (MIMO) transmission. Joint Tx/Rx MMSE filtering transforms the MIMO channel to the orthogonal eigenmodes to avoid the inter-antenna interference (IAI) and performs MMSE based transmit power allocation to sufficiently suppress the inter-symbol interference (ISI) resulting from the severe frequency-selectivity of the channel. Rank adaptation and adaptive modulation are jointly introduced to narrow the gap of received signal-to-interference plus noise power ratio (SINR) among eigenmodes. The superiority of the SC-MIMO transmission with joint Tx/Rx MMSE filtering and joint rank adaptation/adaptive modulation is confirmed by computer simulation.

  • Experimental Study on Arc Duration under Different Atmospheres

    Chen LI  Zhenbiao LI  Qian WANG  Du LIU  Makoto HASEGAWA  Lingling LI  

     
    PAPER

      Vol:
    E97-C No:9
      Page(s):
    843-849

    To clarify the dependence of arc duration on atmosphere, experiments were conducted under conditions of air, N$_{2}$, Ar, He and CO$_{2}$ with the pressure of 0.1,MPa in a 14,V/28,V/42,V circuit respectively. A quantitative relationship between arc duration and gas parameters such as ionization potential, thermal conductivity was obtained from the experimental data. Besides, the inherent mechanism of influence of atmosphere on arc duration was discussed.

  • Experimental Study on Arc Motion and Voltage Fluctuation at Slowly Separating Contact with External DC Magnetic Field

    Yoshiki KAYANO  Kazuaki MIYANAGA  Hiroshi INOUE  

     
    BRIEF PAPER

      Vol:
    E97-C No:9
      Page(s):
    858-862

    Since electromagnetic (EM) noise resulting from an arc discharge disturbs other electric devices, parameters on electromagnetic compatibility, as well as lifetime and reliability, are important properties for electrical contacts. To clarify the characteristics and the mechanism of the generation of the EM noise, the arc column and voltage fluctuations generated by slowly breaking contacts with external direct current (DC) magnetic field, up to 20,mT, was investigated experimentally using Ag$_{90.7{ m wt%}}$SnO$_{2,9.3{ m wt}%}$ material. Firstly the motion of the arc column is measured by high-speed camera. Secondary, the distribution of the motion of the arc and contact voltage are discussed. It was revealed that the contact voltage fluctuation in the arc duration is related to the arc column motion.

  • Experimental Investigation and Numerical Simulation on the Role of Sphere Indenter in Measuring Contact Resistance of Flat Rivets

    Wanbin REN  Yu CHEN  Shengjun XUE  Guenther HORN  Guofu ZHAI  

     
    PAPER

      Vol:
    E97-C No:9
      Page(s):
    873-879

    There has been increasing demand to research the measuring method to characterize the batch consistency of contact rivets. An automated test equipment has been described that makes it possible to measure the electrical contact resistance with high efficiency. The relationship between contact force and contact resistance during the loading and unloading process was measured explicitly using AgPd alloy, stainless steel and sapphire substrate material with Au coatings as sphere indenters separately. To explain the phenomena of contact resistance decreasing more slowly than the traditional theoretical results during loading, the indenter with coating and rivet are modeled by using the commercial FEM software COMSOL Multiphysics. Besides the constriction resistance, the transition region Au coating resistance and the bulk resistance of the substrate are deduced from the simulated current lines profiles and iso-potentials. The difference of electrical conductivity between indenter material and gold coating is the reason for the occurrence of the transition region.

  • A Survey of Intelligent Computing in Medical and Health Care System Open Access

    Yutaka HATA  Hiroshi NAKAJIMA  

     
    INVITED PAPER

      Vol:
    E97-D No:9
      Page(s):
    2218-2225

    This paper gives a survey of intelligent computational techniques in medical and health care system. First, we briefly describe diagnosable techniques in medical image processing. Next, we demonstrate two ultrasonic surgery support systems for orthopedic and rectum cancer surgeons. In them, intelligent computational technique plays a primary role. Third, computational techniques are introduced in human health care system. Usually, this goal is not to apply clinical treatment but to home use to pay consciousness to health. In it, a simple ECG and respiration meter are introduced with a mat sheet which detects heart rate and respiration. Finally, a medical big data application is introduced, that is, body weight prediction is shown based on autoregressive model. Thus, we show that intelligent computing is effective and essential in modern medical and health care system.

  • A Packet Classifier Based on Prefetching EVMDD (k) Machines

    Hiroki NAKAHARA  Tsutomu SASAO  Munehiro MATSUURA  

     
    PAPER-Logic Design

      Vol:
    E97-D No:9
      Page(s):
    2243-2252

    A Decision Diagram Machine (DDM) is a special-purpose processor that has special instructions to evaluate a decision diagram. Since the DDM uses only a limited number of instructions, it is faster than the general-purpose Micro Processor Unit (MPU). Also, the architecture for the DDM is much simpler than that for an MPU. This paper presents a packet classifier using a parallel EVMDD (k) machine. To reduce computation time and code size, first, a set of rules for a packet classifier is partitioned into groups. Then, the parallel EVMDD (k) machine evaluates them. To further speed-up for the standard EVMDD (k) machine, we propose the prefetching EVMDD (k) machine which reads both the index and the jump address at the same time. The prefetching EVMDD (k) machine is 2.4 times faster than the standard one using the same memory size. We implemented a parallel prefetching EVMDD (k) machine consisting of 30 machines on an FPGA, and compared it with the Intel's Core i5 microprocessor running at 1.7GHz. Our parallel machine is 15.1-77.5 times faster than the Core i5, and it requires only 8.1-58.5 percents of the memory for the Core i5.

  • A Lower Bound on the Gate Count of Toffoli-Based Reversible Logic Circuits

    Takashi HIRAYAMA  Hayato SUGAWARA  Katsuhisa YAMANAKA  Yasuaki NISHITANI  

     
    PAPER-Reversible/Quantum Computing

      Vol:
    E97-D No:9
      Page(s):
    2253-2261

    We present a new lower bound on the number of gates in reversible logic circuits that represent a given reversible logic function, in which the circuits are assumed to consist of general Toffoli gates and have no redundant input/output lines. We make a theoretical comparison of lower bounds, and prove that the proposed bound is better than the previous one. Moreover, experimental results for lower bounds on randomly-generated reversible logic functions and reversible benchmarks are given. The results also demonstrate that the proposed lower bound is better than the former one.

  • Asynchronous Stochastic Decoding of LDPC Codes: Algorithm and Simulation Model

    Naoya ONIZAWA  Warren J. GROSS  Takahiro HANYU  Vincent C. GAUDET  

     
    PAPER-VLSI Architecture

      Vol:
    E97-D No:9
      Page(s):
    2286-2295

    Stochastic decoding provides ultra-low-complexity hardware for high-throughput parallel low-density parity-check (LDPC) decoders. Asynchronous stochastic decoding was proposed to demonstrate the possibility of low power dissipation and high throughput in stochastic decoders, but decoding might stop before convergence due to “lock-up”, causing error floors that also occur in synchronous stochastic decoding. In this paper, we introduce a wire-delay dependent (WDD) scheduling algorithm for asynchronous stochastic decoding in order to reduce the error floors. Instead of assigning the same delay to all computation nodes in the previous work, different computation delay is assigned to each computation node depending on its wire length. The variation of update timing increases switching activities to decrease the possibility of the “lock-up”, lowering the error floors. In addition, the WDD scheduling algorithm is simplified for the hardware implementation in order to eliminate time-averaging and multiplication functions used in the original WDD scheduling algorithm. BER performance using a regular (1024, 512) (3,6) LDPC code is simulated based on our timing model that has computation and wire delay estimated under ASPLA 90nm CMOS technology. It is demonstrated that the proposed asynchronous decoder achieves a 6.4-9.8× smaller latency than that of the synchronous decoder with a 0.25-0.3 dB coding gain.

  • Design of an Energy-Efficient Ternary Current-Mode Intra-Chip Communication Link for an Asynchronous Network-on-Chip

    Akira MOCHIZUKI  Hirokatsu SHIRAHAMA  Yuma WATANABE  Takahiro HANYU  

     
    PAPER-Communication for VLSI

      Vol:
    E97-D No:9
      Page(s):
    2304-2311

    An energy-efficient intra-chip communication link circuit with ternary current signaling is proposed for an asynchronous Network-on-Chip. The data signal encoded by an asynchronous three-state protocol is represented by a small-voltage-swing three-level intermediate signal, which results in the reduction of transition delay and achieving energy-efficient data transfer. The three-level voltage is generated by using a combination of dynamically controlled current sources with feedback loop mechanism. Moreover, the proposed circuit contains a power-saving scheme where the dynamically controlled transistors also are utilized. By cutting off the current paths when the data transfer on the communication link is inactive, the power dissipation can be greatly reduced. It is demonstrated that the average data-transfer speed is about 1.5 times faster than that of a binary CMOS implementation using a 130nm CMOS technology at the supply voltage of 1.2V.

  • An Oscillation-Based On-Chip Temperature-Aware Dynamic Voltage and Frequency Scaling Scheme in System-on-a-Chip

    Katherine Shu-Min LI  Yingchieh HO  Yu-Wei YANG  Liang-Bi CHEN  

     
    PAPER-Circuit Implementations

      Vol:
    E97-D No:9
      Page(s):
    2320-2329

    The excessively high temperature in a chip may cause circuit malfunction and performance degradation, and thus should be avoided to improve system reliability. In this paper, a novel oscillation-based on-chip thermal sensing architecture for dynamically adjusting supply voltage and clock frequency in System-on-a-Chip (SoC) is proposed. It is shown that the oscillation frequency of a ring oscillator reduces linearly as the temperature rises, and thus provides a good on-chip temperature sensing mechanism. An efficient Dynamic Voltage-to-Frequency Scaling (DF2VS) algorithm is proposed to dynamically adjust supply voltage according to the oscillation frequencies of the ring oscillators distributed in SoC so that thermal sensing can be carried at all potential hot spots. An on-chip Dynamic Voltage Scaling or Dynamic Voltage and Frequency Scaling (DVS or DVFS) monitor selects the supply voltage level and clock frequency according to the outputs of all thermal sensors. Experimental results on SoC benchmark circuits show the effectiveness of the algorithm that a 10% reduction in supply voltage alone can achieve about 20% power reduction (DVS scheme), and nearly 50% reduction in power is achievable if the clock frequency is also scaled down (DVFS scheme). The chip temperature will be significant lower due to the reduced power consumption.

  • Learning a Two-Dimensional Fuzzy Discriminant Locality Preserving Subspace for Visual Recognition

    Ruicong ZHI  Lei ZHAO  Bolin SHI  Yi JIN  

     
    PAPER-Pattern Recognition

      Vol:
    E97-D No:9
      Page(s):
    2434-2442

    A novel Two-dimensional Fuzzy Discriminant Locality Preserving Projections (2D-FDLPP) algorithm is proposed for learning effective subspace of two-dimensional images. The 2D-FDLPP algorithm is derived from the Two-dimensional Locality Preserving Projections (2D-LPP) by exploiting both fuzzy and discriminant properties. 2D-FDLPP algorithm preserves the relationship degree of each sample belonging to given classes with fuzzy k-nearest neighbor classifier. Also, it introduces between-class scatter constrain and label information into 2D-LPP algorithm. 2D-FDLPP algorithm finds the subspace which can best discriminate different pattern classes and weakens the environment factors according to soft assignment method. Therefore, 2D-FDLPP algorithm has more discriminant power than 2D-LPP, and is more suitable for recognition tasks. Experiments are conducted on the MNIST database for handwritten image classification, the JAFFE database and Cohn-Kanade database for facial expression recognition and the ORL database for face recognition. Experimental results reported the effectiveness of our proposed algorithm.

  • Open Domain Continuous Filipino Speech Recognition: Challenges and Baseline Experiments

    Federico ANG  Rowena Cristina GUEVARA  Yoshikazu MIYANAGA  Rhandley CAJOTE  Joel ILAO  Michael Gringo Angelo BAYONA  Ann Franchesca LAGUNA  

     
    PAPER-Speech and Hearing

      Vol:
    E97-D No:9
      Page(s):
    2443-2452

    In this paper, a new database suitable for HMM-based automatic Filipino speech recognition is described for the purpose of training a domain-independent, large-vocabulary continuous speech recognition system. Although it is known that high-performance speech recognition systems depend on a superior speech database used in the training stage, due to the lack of such an appropriate database, previous reports on Filipino speech recognition had to contend with serious data sparsity issues. In this paper we alleviate such sparsity through appropriate data analysis that makes the evaluation results more reliable. The best system is identified through its low word-error rate to a cross-validation set containing almost three hours of unknown speech data. Language-dependent problems are discussed, and their impact on accuracy was analyzed. The approach is currently data driven, however it serves as a competent baseline model for succeeding future developments.

  • Speech Emotion Recognition Using Transfer Learning

    Peng SONG  Yun JIN  Li ZHAO  Minghai XIN  

     
    LETTER-Speech and Hearing

      Vol:
    E97-D No:9
      Page(s):
    2530-2532

    A major challenge for speech emotion recognition is that when the training and deployment conditions do not use the same speech corpus, the recognition rates will obviously drop. Transfer learning, which has successfully addressed the cross-domain classification or recognition problem, is presented for cross-corpus speech emotion recognition. First, by using the maximum mean discrepancy embedding (MMDE) optimization and dimension reduction algorithms, two close low-dimensional feature spaces are obtained for source and target speech corpora, respectively. Then, a classifier function is trained using the learned low-dimensional features in the labeled source corpus, and directly applied to the unlabeled target corpus for emotion label recognition. Experimental results demonstrate that the transfer learning method can significantly outperform the traditional automatic recognition technique for cross-corpus speech emotion recognition.

  • Compact Reconfigurable Wideband Inverted-F Antenna for LTE MIMO Mobile Applications

    Xing ZHAO  Jaehoon CHOI  

     
    PAPER-Antennas and Propagation

      Vol:
    E97-B No:9
      Page(s):
    1921-1927

    In this paper, compact reconfigurable wideband Inverted-F Antenna (IFA) elements are proposed for a Long Term Evolution (LTE) mobile terminal. The proposed inverted-F antenna has a very simple planar arrangement. A capacitive coupling feed strip is employed to modify the input impedance matching. A chip inductor is connected in series to the feeding point to realize the wideband property. The whole Multiple-Input Multiple-Output (MIMO) antenna system consists of two similar inverted-F antenna elements. Antenna element #1 has a wideband property with a 6-dB bandwidth from 0.74 to 0.9GHz. To further expand the bandwidth, antenna element #2 has a reconfigurable property through the use of a Positive Intrinsic-Negative (PIN) diode. Antenna element #2 has a 6-dB bandwidth from 0.74 to 0.84GHz when the PIN diode is on and from 0.79 to 0.9GHz when the PIN diode is off. Moreover, the proposed MIMO antenna has a low radiation-pattern-based envelope correlation coefficient (ECC), which is less than 0.15 over LTE bands 4, 5, 13, and 14.

  • Scalable Connection-Based Time Division Multiple Access Architecture for Wireless Network-on-Chip

    Shijun LIN  Zhaoshan LIU  Jianghong SHI  Xiaofang WU  

     
    BRIEF PAPER-Integrated Electronics

      Vol:
    E97-C No:9
      Page(s):
    918-921

    In this paper, we propose a scalable connection-based time division multiple access architecture for wireless NoC. In this architecture, only one-hop transmission is needed when a packet is transmitted from one wired subnet to another wired subnet, which improves the communication performance and cuts down the energy consumption. Furthermore, by carefully designing the central arbiter, the bandwidth of the wireless channel can be fully used. Simulation results show that compared with the traditional WCube wireless NoC architecture, the proposed architecture can greatly improve the network throughput, and cut down the transmission latency and energy consumption with a reasonable area overhead.

  • FOREWORD Open Access

    Ryo NAGASE  

     
    FOREWORD

      Vol:
    E97-C No:9
      Page(s):
    842-842
  • Design of Wideband Coupled Line DC Block with Compact Size

    Byungjoon KIM  Sangwook NAM  Hee-Ran AHN  Jae-Hoon SONG  

     
    BRIEF PAPER-Microwaves, Millimeter-Waves

      Vol:
    E97-C No:9
      Page(s):
    915-917

    This letter proposes a wideband compact DC block design technique. This DC block has a wide pass-band and wide stop-band and transforms termination impedances. It comprises a pair of coupled lines on a defected ground structure (DGS) with capacitor loading. A periodic DGS pattern increases coupling, and, consequently, a wideband DC block design is allowed with a microstrip process on a high dielectric low height substrate. A DC block with equal termination impedances of 50,$Omega$ and another that transforms 50 into 30,$Omega$ are fabricated. The measured fractional bandwidths are 48% and 47%. The size of the DC block is 16.8$ imes$ 15,mm$^2(0.057lambda_0 imes 0.051lambda_0)$.

  • Roundoff Noise Minimization for a Class of 2-D State-Space Digital Filters Using Joint Optimization of High-Order Error Feedback and Realization

    Akimitsu DOI  Takao HINAMOTO  Wu-Sheng LU  

     
    PAPER-Digital Signal Processing

      Vol:
    E97-A No:9
      Page(s):
    1918-1925

    For two-dimensional IIR digital filters described by the Fornasini-Marchesini second model, the problem of jointly optimizing high-order error feedback and realization to minimize the effects of roundoff noise at the filter output subject to l2-scaling constraints is investigated. The problem at hand is converted into an unconstrained optimization problem by using linear-algebraic techniques. The unconstrained optimization problem is then solved iteratively by applying an efficient quasi-Newton algorithm with closed-form formulas for key gradient evaluation. Finally, a numerical example is presented to illustrate the validity and effectiveness of the proposed technique.

  • A Resource Analysis of Radio Space Distribution for the Wide-Area Virtualization of Wireless Transceivers

    Yuusuke KAWAKITA  Haruhisa ICHIKAWA  

     
    PAPER

      Vol:
    E97-B No:9
      Page(s):
    1800-1807

    Wide area virtualization of wireless transceivers by centrally managed software radio systems is a way to efficiently share the resources for supporting a variety of wireless protocols. In order to enable wide-area virtualization of wireless transceivers, the authors have developed a mechanism to deliver the radio space information which is quantized broadband radio wave information including the radio signals to the transceivers. Delivery mechanism consists of a distribution server which distributes radio space corresponding to the request of the client such as the center frequency and the bandwidth and a client which uses the radio space information. Accumulation of the distribution servers which deliver radio space information simultaneously to a large number of clients will contribute to build an infrastructure for any clients ubiquitously distributed over the globe. In this paper, scale-out architecture of a distribution server is proposed to deliver unlimitedly broadband radio space information to unlimited number of clients. Experimental implementation indicates the architecture to be a scale-out solution, while the number of clients is restricted by the computer resources of the distribution server. The band pass filter processing for individual client in the distribution server consumes the dominant part of the processing power, and the number of CPU cores is the upper limit of clients supportable for the distribution server in the current operating system implementation. The logical increase of the number of CPU cores by hardware multithreading does not contribute to relax this limit. We also discuss the guidance architecture or building server derived from these conclusions.

9581-9600hit(42807hit)