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[Keyword] reduction(403hit)

301-320hit(403hit)

  • An Improved Algorithm to Compute Marginal Reliability Importance in a Network System

    Takeshi KOIDE  Shuichi SHINMORI  Hiroaki ISHII  

     
    PAPER-Reliability, Maintainability and Safety Analysis

      Vol:
    E87-A No:2
      Page(s):
    454-460

    Marginal reliability importance (MRI) of a component in a system is defined as the rate at which the system reliability changes over changes of the component reliability. MRI helps network designers to construct a reliable network layout. We consider a problem to compute MRI of all components in a network system considering all-terminal reliability in order to rank the components with respect to MRI. The problem is time-consuming since computing network reliability is #P-complete. This paper improves the traditional approach for the problem to proposes an efficient algorithm. The algorithm applies some network transformations, three network reductions and one network decomposition. We have proved lemmas with respect to the relationship between the transformations and MRI, which compute MRI for an original network by using MRI and reliability for transformed networks. Additionally, we have derived a deformed formula to compute MRI, which can also reduce computational task. Numerical experiments revealed that the proposed algorithm reduced computational time considerably compared to the traditional approach.

  • Macromodel Generation for Hybrid Systems Consisting of Electromagnetic Systems and Lumped RLC Circuits Based on Model Order Reduction

    Takayuki WATANABE  Hideki ASAI  

     
    PAPER

      Vol:
    E87-A No:2
      Page(s):
    398-405

    This paper describes an efficient method for the macromodel generation of hybrid systems which are composed of electromagnetic systems and lumped RLC circuits. In our method, electromagnetic systems are formulated as finite-difference frequency-domain (FDFD) equations, and RLC circuits are formulated as nodal equations. Therefore, unlike the partial-element equivalent-circuit (PEEC) method, the technique presented here does not need any 3-dimensional capacitance and inductance parameter extractions to model interconnects, LSI packages and printed circuit boards. Also the lumped RLC elements can be easily included in the hybrid system of equations, thus it is convenient to model some passive components, such as bypass capacitors. The model order reduction technique is utilized in order to construct macromodels from hybrid system of equations. The accuracy of the proposed method is substantiated with some numerical examples.

  • OAEP-ES--Methodology of Universal Padding Technique--

    Yuichi KOMANO  Kazuo OHTA  

     
    PAPER-Asymmetric Cipher

      Vol:
    E87-A No:1
      Page(s):
    110-119

    The new concept of ES (Encryption-Signature) schemes which realize an encryption scheme and a signature scheme with a unique padding technique and key pair, was proposed by Coron et al. They also gave a proof of PSS-ES. In this paper, first, we discuss the methodology for the construction for ES schemes by using padding techniques of encryption schemes, and propose a new ES scheme, OAEP-ES, adopting this methodology. It is proven that OAEP-ES scheme can be constructed under the assumption of the one-wayness of the encryption permutation, while the security of PSS-ES utilized as an encryption scheme is based on the partial-domain one-wayness; which is a theoretical progress since the one-wayness is more general assumption than the partial-domain one-wayness. It is shown that OAEP-ES attains tighter security than PSS-ES, which is a practical interest.

  • Bipolar Scan Waveform for Fast Address in AC Plasma Display Panel

    Ki-Duck CHO  Heung-Sik TAE  Sung-Il CHIEN  

     
    LETTER-Electronic Displays

      Vol:
    E87-C No:1
      Page(s):
    116-119

    A new bipolar scan waveform is proposed to increase the light emission duty factor by achieving the fast address in AC plasma display panel (AC-PDP). The new bipolar scan waveform consists of two-step scan pulse, which can separate the address discharge mode into two different discharge modes: a space charge generation mode and a wall charge accumulation mode. By adopting the new bipolar scan waveform, the light emission duty factor is increased considerably under the single scan ADS driving scheme due to the reduction of address time per single subfield.

  • A New Fast Image Retrieval Using the Condensed Two-Stage Search Method

    JungWon CHO  SeungDo JEONG  GeunSeop LEE  SungHo CHO  ByungUk CHOI  

     
    LETTER-Multimedia Systems

      Vol:
    E86-B No:12
      Page(s):
    3658-3661

    In a content-based image retrieval (CBIR) system, both the retrieval relevance and the response time are very important. This letter presents the condensed two-stage search method as a new fast image retrieval approach by making use of the property of Cauchy-Schwarz inequality. The method successfully reduces the overall processing time for similarity computation, while maintaining the same retrieval relevance as the conventional exhaustive search method. By the extensive computer simulations, we observe that the condensed two-stage search method is more effective as the number of images and dimensions of the feature space increase.

  • Leakage Power Reduction for Battery-Operated Portable Systems

    Yun CAO  Hiroto YASUURA  

     
    LETTER-Power Optimization

      Vol:
    E86-A No:12
      Page(s):
    3200-3203

    This paper addresses bitwidth optimization focusing on leakage power reduction for system-level low-power design. By means of tuning the design parameter, bitwidth tailored to a given application requirements, the datapath width of processors and size of memories are optimized resulting in significant leakage power reduction besides dynamic power reduction. Experimental results for several real embedded applications, show power reduction without performance penalty range from about 21.5% to 66.2% of leakage power, and 14.5% to 59.2% of dynamic power.

  • Transmit Power and Window Control to Reduce Inter-User Interference in CDMA Cellular Packet Systems

    Hiroyuki KAWAI  Shinzo OHKUBO  Toru OTSU  Hirohito SUDA  Yasushi YAMAO  

     
    PAPER

      Vol:
    E86-A No:7
      Page(s):
    1698-1706

    A novel interference reduction method, transmit power and window control (TPWC), is proposed to enhance the system capacity in the downlink of code division multiple access (CDMA) cellular packet systems. TPWC measures the propagation conditions and calculates the required instantaneous transmit power between a base station (BS) and a mobile station (MS). Then, TPWC sends packets only during a transmit time-window, in which the packets can be sent with less power than a predetermined threshold. TPWC reduces the average transmit power at the cost of an extra transmission delay at the BS. Computer simulations show that TPWC enhances the system capacity by two-fold in a CDMA cellular packet system when each MS has a loading ratio of 0.5 and an average delay allowance of 5 ms for the unit packet length of 1 ms. Furthermore, this paper proposes a multi-link packet transmission (MLPT) scheme in order to reduce the delay caused by TPWC. When an MS is at the cell edge, packets are distributed by MLPT to multiple BSs, from which packets are sent to the MS; thus, the transmission delay can be reduced by utilizing the transmit windows of each BS.

  • Improvement of Cone Beam CT Image Using Singularity Detection

    Yi-Qiang YANG  Nobuyuki NAKAMORI  Yasuo YOSHIDA  

     
    PAPER

      Vol:
    E86-D No:7
      Page(s):
    1206-1213

    In medical diagnosis, cone beam CT increases the dose absorbed by a patient. However, the radiographic noise (such as quantum noise) in a CT image increases when radiation exposure is reduced. In this paper, we propose a method to improve the CT image degraded by the quantum mottle based on 2-D wavelet transform modulus sum (WTMS). The noise and regular parts of an image can be observed by tracing the evolution of its 2-D WTMS across scales. Our experimental results show that most of the quantum mottle in the 2-D projections is removed by the proposed method and the edges preserved well. We investigate the relation between the number of X-ray photons and the quality of the denoised images. The result shows the possibility that a patient's dose can be reduced about 10% with the same visual quality by our method.

  • Peak Power Reduction Technique for Subcarrier Transmit Power Control Applied OFDM Systems

    Yuuhei HASHIMOTO  Seiichi SAMPEI  Norihiko MORINAGA  

     
    LETTER-Wireless Communication Technology

      Vol:
    E86-B No:7
      Page(s):
    2207-2210

    A peak power reduction technique is proposed for subcarrier transmit power control applied orthogonal frequency division multiplexing (OFDM) system. In the proposed system, carrier-holes are created by applying a partial non-power allocation (PNPA) technique in which no transmit power is allocated to subcarriers with lower received Eb/N0, and the amplitude and phase adjusted peak reduction subcarrier (PRS) is iteratively inserted in the non-power allocated subcarrier so as to suppress peak power. Computer simulation confirms that the proposed scheme can reduce peak power by 3.6 dB while keeping the same information bit-rate with conventional subcarrier transmit power control applied OFDM systems.

  • A Peak Reduction Scheme Based on Control Signal Insertion for Multi-Carrier Mobile Communication Systems

    Shigeru TOMISATO  Hiroshi SUZUKI  

     
    PAPER-Wireless Communication Technology

      Vol:
    E86-B No:6
      Page(s):
    1910-1916

    This paper proposes a new signal peak power reduction technique, Peak Reduction based on Control Signal Insertion (PRCSI), for broadband mobile communications based on multi-channel signaling schemes. PRCSI reduces the peak power with a peak control signal that is generated symbol-by-symbol; no signal band expansion is incurred because the peak control signal is inserted into the transmission signal band. PRCSI can achieve 4 dB peak power reduction for 8-carrier signaling, while the Eb/N0 value required to achieve 10-3 average BER is 1 dB larger with PRCSI than without it. This BER performance degradation can effectively be compensated by the proper use of Trellis coding. The proposed technique is applied to OFDM transmission systems with large carrier number. The proposed technique can achieve 3-dB peak power ratio for 128-carrier OFDM signals with less than 1-dB performance degradation at the BER of 10-3.

  • On the Security of Girault Key Agreement Protocols against Active Attacks

    Soo-Hyun OH  Masahiro MAMBO  Hiroki SHIZUYA  Dong-Ho WON  

     
    PAPER

      Vol:
    E86-A No:5
      Page(s):
    1181-1189

    In 1991 Girault proposed a key agreement protocol based on his new idea of self-certified public key. Later Rueppel and Oorschot showed variants of the Girault scheme. All of these key agreement protocols inherit positive features of self-certified public key so that they can provide higher security and smaller communication overhead than key agreement protocols not based on self-certified public key. Even with such novel features, rigorous security of these protocols has not been made clear yet. In this paper, we give rigorous security analysis of the original and variants of Girault key agreement protocol under several kinds of active attacker models. In particular we show that protocols are either insecure or proven as secure as the Diffie-Hellman problem over Zn with respect to the reduction among functions of computing them. Analyzed protocols include a new variant of 1-pass protocol. As opposed to the original 1-pass protocol, the new variant provides mutual implicit key authentication without increasing the number of passes.

  • 155-Mb/s Burst-Mode Clock Recovery Circuit Using the Jitter Reduction Technique

    Jae-Seung HWANG  Chul-Soo PARK  Chang-Soo PARK  

     
    LETTER-Fiber-Optic Transmission

      Vol:
    E86-B No:4
      Page(s):
    1423-1426

    We propose a simple technique for reducing the jitter of the output clock generated in the clock recovery circuit (CRC) for burst-mode data transmission. By using this technique, the proposed CRC based on the gated oscillator (GO) can recover the output clock with a low-jitter even when there are consecutive same data streams encountered in the system. The circuit is composed only of digital logic devices and can recover the input data errorless until 1,000 consecutive same data bits are incoming.

  • Speech Enhancement by Profile Fitting Method

    Osamu ICHIKAWA  Tetsuya TAKIGUCHI  Masafumi NISHIMURA  

     
    PAPER-Robust Speech Recognition and Enhancement

      Vol:
    E86-D No:3
      Page(s):
    514-521

    It is believed that distant-talking speech recognition in a noisy environment requires a large-scale microphone array. However, this cannot fit into small consumer devices. Our objective is to improve the performance with a limited number of microphones (preferably only left and right). In this paper, we focused on a profile that is the shape of the power distribution according to the beamforming direction. An observed profile can be decomposed into known profiles for directional sound sources and a non-directional background sound source. Evaluations confirmed this method reduced the CER (Character Error Ratio) for the dictation task by more than 20% compared to a conventional 2-channel Adaptive Spectral Subtraction beamformer in a non-reverberant environment.

  • TCAD Driven Drain Engineering for Hot Carrier Reduction of 3.3 V I/O PMOSFET

    Noriyuki MIURA  Hirotaka KOMATSUBARA  Marie MOCHIZUKI  Hirokazu HAYASHI  Koichi FUKUDA  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    447-452

    In this paper, we propose a TCAD driven hot carrier reduction methodology of 3.3 V I/O pMOSFETs design. The hot carrier reliability of surface channel I/O pMOSFET having drain structure in common with core devices has a critical issue. It is substantially important for the high-reliability devices to reduce both drain avalanche and channel hot hole components. The drain structures are successfully optimized in short time by applications of TCAD local models. Considering tradeoffs between hot carrier injection (HCI) and drive current (ION), SDE/HALO of both core and I/O transistors can be totally optimized for reduction of process-steps and/or photo-masks.

  • Automatic Generation of Compact Electro-Thermal Models for Semiconductor Devices

    Tamara BECHTOLD  Evgenii B. RUDNYI  Jan G. KORVINK  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    459-465

    A high power dissipation density in today's miniature electronic/mechanical systems makes on-chip thermal management very important. In order to achieve quick to evaluate, yet accurate electro-thermal models, needed for the thermal management of microsystems, a model order reduction is necessary. In this paper, we present an automatic, Krylov-subspace-based order reduction of a electro-thermal model, which we illustrate by a novel type of micropropulsion device. Numerical simulation results of the full finite element model and the reduced order model, that describes the transient electro-thermal behavior, are presented. A comparison between Krylov-subspace-based order reduction, order reduction using control theoretical approaches and commercially available reduced order modeling has been performed. A Single-Input-Single-Output setup for the Arnoldi reduction algorithm was proved to be sufficient to accurately represent the complete time-dependent temperature distribution of the device.

  • Image Feature Extraction Algorithm for Support Vector Machines Using Multi-Layer Block Model

    Wonjun HWANG  Hanseok KO  

     
    PAPER-Pattern Recognition

      Vol:
    E86-D No:3
      Page(s):
    623-632

    This paper concerns recognizing 3-dimensional object using proposed multi-layer block model. In particular, we aim to achieve desirable recognition performance while restricting the computational load to a low level using 3-step feature extraction procedure. An input image is first precisely partitioned into hierarchical layers of blocks in the form of base blocks and overlapping blocks. The hierarchical blocks are merged into a matrix, with which abundant local feature information can be obtained. The local features extracted are then employed by the kernel based support vector machines in tournament for enhanced system recognition performance while keeping it to low dimensional feature space. The simulation results show that the proposed feature extraction method reduces the computational load by over 80% and preserves the stable recognition rate from varying illumination and noise conditions.

  • An Analytic Approximation of Information Reduction Factor for Performance Prediction of PDA Tracking

    Sun-Mog HONG  Han-Seop SHIN  

     
    LETTER-Navigation, Guidance and Control Systems

      Vol:
    E86-B No:2
      Page(s):
    873-875

    An analytic approximation of the information reduction factor is presented in an efficient manner for the case of two-dimensional measurement vector and a four-sigma validation gate. This analytic approximation allows us to efficiently evaluate performance prediction for the probabilistic data association (PDA) filter using the hybrid conditional average (HYCA) algorithm.

  • Application-Level Jitter Reduction Scheme for Multimedia Communication over ATM-ABR Service

    Naotoshi ADACHI  Shoji KASAHARA  Yutaka TAKAHASHI  

     
    PAPER-Network

      Vol:
    E86-B No:2
      Page(s):
    798-808

    The ATM-ABR service category provides minimum cell rate (MCR) guarantees and robust connections even with insufficient network resources. Recently proposed rate-management algorithms for supporting multimedia applications over ABR mainly aim at minimizing the cell loss and delay. However, jitter is also an important element of QoS for multimedia applications. In this paper, we focus our attention on the arrival point of the critical cell corresponding to the end of data packet and propose a simple cell scheduling scheme for source node to reduce the jitter on application level over the ATM-ABR service class. In our proposed method, critical cells are delayed intentionally and the packet stream at application level becomes smooth. We verify the effectiveness of our proposed algorithm by an analytical model and simulation. From those results, we find that our proposed scheduling algorithm is effective in reducing the application level jitter even when the tagged cell stream is transmitted along the path with multiple nodes.

  • Improvement of CT Image Degraded by Quantum Mottle Using Singularity Detection

    Yi-Qiang YANG  Nobuyuki NAKAMORI  Yasuo YOSHIDA  

     
    PAPER-Medical Engineering

      Vol:
    E86-D No:1
      Page(s):
    123-130

    To improve the CT image degraded by radiographic noise (such as quantum mottle), we propose a method based on the wavelet transform modulus sum (WTMS). The noise and regular parts of a signal can be observed by tracing the evolution of its WTMS across scales. Our results show that most of the quantum mottle in the projections of Shepp-Logan phantom has been removed by the proposed method with the supposed cranium well preserved. The denoised CT images show good signal to noise ratio in the region of interest. We also have investigated the relation between the number of X-ray photons and the quality of images reconstructed from denoised projections. From experimental results, this method shows the possibility to reduce a patient's dose about 1/10 with the same visual quality.

  • Modular Synthesis of Timed Circuits Using Partial Order Reduction

    Tomohiro YONEDA  Eric MERCER  Chris MYERS  

     
    PAPER-Logic Synthesis

      Vol:
    E85-A No:12
      Page(s):
    2684-2692

    This paper develops a modular synthesis algorithm for timed circuits that is dramatically accelerated by partial order reduction. This algorithm synthesizes each module in a hierarchical design individually. It utilizes partial order reduction to reduce the state space explored for the other modules by considering a single interleaving of concurrently enabled transitions. This approach better manages the state explosion problem resulting in a more than 2 order of magnitude reduction in synthesis time. The improved synthesis time enables the synthesis of a larger class of timed circuits than was previously possible.

301-320hit(403hit)