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  • Scan Chain Ordering to Reduce Test Data for BIST-Aided Scan Test Using Compatible Scan Flip-Flops

    Hiroyuki YOTSUYANAGI  Masayuki YAMAMOTO  Masaki HASHIZUME  

     
    PAPER

      Vol:
    E93-D No:1
      Page(s):
    10-16

    In this paper, the scan chain ordering method for BIST-aided scan test for reducing test data and test application time is proposed. In this work, we utilize the simple LFSR without a phase shifter as PRPG and configure scan chains using the compatible set of flip-flops with considering the correlations among flip-flops in an LFSR. The method can reduce the number of inverter codes required for inverting the bits in PRPG patterns that conflict with ATPG patterns. The experimental results for some benchmark circuits are shown to present the feasibility of our test method.

  • An Instantaneous Frequency Estimator Based on the Symmetric Higher Order Differential Energy Operator

    Byeong-Gwan IEM  

     
    PAPER-Digital Signal Processing

      Vol:
    E93-A No:1
      Page(s):
    227-232

    A generalized formulation of the instantaneous frequency based on the symmetric higher order differential energy operator is proposed. The motivation for the formulation is that there is some frequency misalignment in time when the ordinary higher order differential energy operator is used for the instantaneous frequency estimator. The special cases of the generalized formulation are also presented. The proposed instantaneous frequency estimators are compared with existing methods in terms of error performance measured in the mean absolute error. In terms of the estimation error performance, the third order instantaneous frequency estimator with the symmetrical structure shows the best result under noise free condition. Under noisy situation, the fourth order instantaneous frequency estimator with the symmetrical structure produces the best results. Application examples are provided to show the usefulness of the estimator.

  • Numerical Investigation of Conformal ADI-FDTD Schemes with Second-Order Convergence

    Kazuhiro FUJITA  Yoichi KOCHIBE  Takefumi NAMIKI  

     
    PAPER

      Vol:
    E93-C No:1
      Page(s):
    52-59

    This paper presents unconditionally stable and conformal FDTD schemes which are based on the alternating-direction implicit finite difference time domain (ADI-FDTD) method for accurate modeling of perfectly electric conducting (PEC) objects. The proposed schemes are formulated within the framework of the matrix-vector notation of the finite integration technique (FIT), which allows a systematic and consistent extension of finite difference solution of Maxwell's equations on dual grids. As possible choices of second-order convergent conformal method, we apply the partially filled cell (PFC) and the uniformly stable conformal (USC) schemes for the ADI-FDTD method. The unconditional stability and the rates of convergence of the proposed conformal ADI-FDTD (CADI-FDTD) schemes are verified by means of numerical examples of waveguide problems.

  • A Reordering Model Using a Source-Side Parse-Tree for Statistical Machine Translation

    Kei HASHIMOTO  Hirofumi YAMAMOTO  Hideo OKUMA  Eiichiro SUMITA  Keiichi TOKUDA  

     
    PAPER-Machine Translation

      Vol:
    E92-D No:12
      Page(s):
    2386-2393

    This paper presents a reordering model using a source-side parse-tree for phrase-based statistical machine translation. The proposed model is an extension of IST-ITG (imposing source tree on inversion transduction grammar) constraints. In the proposed method, the target-side word order is obtained by rotating nodes of the source-side parse-tree. We modeled the node rotation, monotone or swap, using word alignments based on a training parallel corpus and source-side parse-trees. The model efficiently suppresses erroneous target word orderings, especially global orderings. Furthermore, the proposed method conducts a probabilistic evaluation of target word reorderings. In English-to-Japanese and English-to-Chinese translation experiments, the proposed method resulted in a 0.49-point improvement (29.31 to 29.80) and a 0.33-point improvement (18.60 to 18.93) in word BLEU-4 compared with IST-ITG constraints, respectively. This indicates the validity of the proposed reordering model.

  • Fast Analysis of On-Chip Power Grid Circuits by Extended Truncated Balanced Realization Method

    Duo LI  Sheldon X.-D. TAN  

     
    PAPER-Device and Circuit Modeling and Analysis

      Vol:
    E92-A No:12
      Page(s):
    3061-3069

    In this paper, we present a novel analysis approach for large on-chip power grid circuit analysis. The new approach, called ETBR for extended truncated balanced realization, is based on model order reduction techniques to reduce the circuit matrices before the simulation. Different from the (improved) extended Krylov subspace methods EKS/IEKS, ETBR performs fast truncated balanced realization on response Gramian to reduce the original system. ETBR also avoids the adverse explicit moment representation of the input signals. Instead, it uses spectrum representation in frequency domain for input signals by fast Fourier transformation. The proposed method is very amenable for threading-based parallel computing, as the response Gramian is computed in a Monte-Carlo-like sampling style and each sampling can be computed in parallel. This contrasts with all the Krylov subspace based methods like the EKS method, where moments have to be computed in a sequential order. ETBR is also more flexible for different types of input sources and can better capture the high frequency contents than EKS, and this leads to more accurate results especially for fast changing input signals. Experimental results on a number of large networks (up to one million nodes) show that, given the same order of the reduced model, ETBR is indeed more accurate than the EKS method especially for input sources rich in high-frequency components. If parallel computing is explored, ETBR can be an order of magnitude faster than the EKS/IEKS method.

  • Chaotic Order Preserving Encryption for Efficient and Secure Queries on Databases

    Seungmin LEE  Tae-Jun PARK  Donghyeok LEE  Taekyong NAM  Sehun KIM  

     
    PAPER-Database

      Vol:
    E92-D No:11
      Page(s):
    2207-2217

    The need for data encryption that protects sensitive data in a database has increased rapidly. However, encrypted data can no longer be efficiently queried because nearly all of the data should be decrypted. Several order-preserving encryption schemes that enable indexes to be built over encrypted data have been suggested to solve this problem. They allow any comparison operation to be directly applied to encrypted data. However, one of the main disadvantages of these schemes is that they expose sensitive data to inference attacks with order information, especially when the data are used together with unencrypted columns in the database. In this study, a new order-preserving encryption scheme that provides secure queries by hiding the order is introduced. Moreover, it provides efficient queries because any user who has the encryption key knows the order. The proposed scheme is designed to be efficient and secure in such an environment. Thus, it is possible to encrypt only sensitive data while leaving other data unencrypted. The encryption is not only robust against order exposure, but also shows high performance for any query over encrypted data. In addition, the proposed scheme provides strong updates without assumptions of the distribution of plaintext. This allows it to be integrated easily with the existing database system.

  • State-of-the-Art Word Reordering Approaches in Statistical Machine Translation: A Survey

    Marta R. COSTA-JUSSA  Jose A. R. FONOLLOSA  

     
    SURVEY PAPER-Natural Language Processing

      Vol:
    E92-D No:11
      Page(s):
    2179-2185

    This paper surveys several state-of-the-art reordering techniques employed in Statistical Machine Translation systems. Reordering is understood as the word-order redistribution of the translated words. In original SMT systems, this different order is only modeled within the limits of translation units. Relying only in the reordering provided by translation units may not be good enough in most language pairs, which might require longer reorderings. Therefore, additional techniques may be deployed to face the reordering challenge. The Statistical Machine Translation community has been very active recently in developing reordering techniques. This paper gives a brief survey and classification of several well-known reordering approaches.

  • Static Dependency Pair Method Based on Strong Computability for Higher-Order Rewrite Systems

    Keiichirou KUSAKARI  Yasuo ISOGAI  Masahiko SAKAI  Frederic BLANQUI  

     
    PAPER-Computation and Computational Models

      Vol:
    E92-D No:10
      Page(s):
    2007-2015

    Higher-order rewrite systems (HRSs) and simply-typed term rewriting systems (STRSs) are computational models of functional programs. We recently proposed an extremely powerful method, the static dependency pair method, which is based on the notion of strong computability, in order to prove termination in STRSs. In this paper, we extend the method to HRSs. Since HRSs include λ-abstraction but STRSs do not, we restructure the static dependency pair method to allow λ-abstraction, and show that the static dependency pair method also works well on HRSs without new restrictions.

  • Imposing Constraints from the Source Tree on ITG Constraints for SMT

    Hirofumi YAMAMOTO  Hideo OKUMA  Eiichiro SUMITA  

     
    PAPER-Natural Language Processing

      Vol:
    E92-D No:9
      Page(s):
    1762-1770

    In the current statistical machine translation (SMT), erroneous word reordering is one of the most serious problems. To resolve this problem, many word-reordering constraint techniques have been proposed. Inversion transduction grammar (ITG) is one of these constraints. In ITG constraints, target-side word order is obtained by rotating nodes of the source-side binary tree. In these node rotations, the source binary tree instance is not considered. Therefore, stronger constraints for word reordering can be obtained by imposing further constraints derived from the source tree on the ITG constraints. For example, for the source word sequence { a b c d }, ITG constraints allow a total of twenty-two target word orderings. However, when the source binary tree instance ((a b) (c d)) is given, our proposed "imposing source tree on ITG" (IST-ITG) constraints allow only eight word orderings. The reduction in the number of word-order permutations by our proposed stronger constraints efficiently suppresses erroneous word orderings. In our experiments with IST-ITG using the NIST MT08 English-to-Chinese translation track's data, the proposed method resulted in a 1.8-points improvement in character BLEU-4 (35.2 to 37.0) and a 6.2% lower CER (74.1 to 67.9%) compared with our baseline condition.

  • Proximity Coupled Interconnect Using Broadside Coupled Composite Right/Left-Handed Transmission Line

    Naobumi MICHISHITA  Akiyoshi ABE  Yoshihide YAMADA  Anthony LAI  Tatsuo ITOH  

     
    PAPER

      Vol:
    E92-C No:9
      Page(s):
    1150-1156

    In this paper, the feasibility of composite right/left-handed transmission lines for realizing proximity coupled interconnects is reported. The proposed interconnects' resonant length can be miniaturized due to the zeroth order resonance supported by a composite right/left-handed transmission line resonator. In addition, the proposed interconnects can achieve broadside coupling because the zeroth order resonance occurs in the fast-wave region. Simulated and measured electric field distributions are shown to explain the broadside coupling phenomenon. To validate the arbitrary size and broadside coupling of the proposed interconnects, simulated and measured transmission characteristics are presented. The results show that low insertion loss can be achieved by using single and double broadside coupling between interconnects.

  • Low-Pass Filter Property of an Input-Dimensional Output Feedback Passification Controller for Rotary Inverted Pendulum

    Young Ik SON  Nam Hoon JO  Hyungbo SHIM  Goo-Jong JEONG  

     
    LETTER-Systems and Control

      Vol:
    E92-A No:8
      Page(s):
    2133-2136

    A rotary inverted pendulum is stabilized by a single first order dynamic output feedback system. Numerical simulations and experimental results show that the proposed control law has low-pass filter property as well as it can successfully replace the velocity measurements for LQR control law.

  • Robust Channel Order Selection Based on Spectral Matching

    Koji HARADA  Hideaki SAKAI  

     
    PAPER-Communications

      Vol:
    E92-A No:8
      Page(s):
    1898-1904

    In this paper, a new approach to channel order selection of single-input multiple-output (SIMO), finite impulse response (FIR) channels is proposed for blind channel estimation. The approach utilizes cross spectral density (CSD) of the channel outputs, and minimizes the distance between two CSD's, one calculated non-parametrically from the observed output data, and the other calculated from the blindly estimated channel parameters. The CSD criterion is numerically tested on randomly generated SIMO-FIR channels, and shown to be very effective compared to existing channel order selection methods especially under low SNR settings. Blind estimates of the channels with the selected channel order also show superiority of the CSD criterion.

  • Threshold-Based OSIC Detection Algorithm for Per-Antenna-Coded TIMO-OFDM Systems

    Xinzheng WANG  Ming CHEN  Pengcheng ZHU  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E92-B No:7
      Page(s):
    2512-2515

    Threshold-based ordered successive interference cancellation (OSIC) detection algorithm is proposed for per-antenna-coded (PAC) two-input multiple-output (TIMO) orthogonal frequency division multiplexing (OFDM) systems. Successive interference cancellation (SIC) is performed selectively according to channel conditions. Compared with the conventional OSIC algorithm, the proposed algorithm reduces the complexity significantly with only a slight performance degradation.

  • Robust Reduced Order Observer for Lipschitz Nonlinear Systems

    Sungryul LEE  

     
    LETTER-Systems and Control

      Vol:
    E92-A No:6
      Page(s):
    1530-1534

    This paper presents a robust reduced order observer for a class of Lipschitz nonlinear systems with external disturbance. Sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level. Finally, a numerical example is provided to verify the proposed design method.

  • A Reordering Heuristic for Accelerating the Convergence of the Solution of Some Large Sparse PDE Matrices on Structured Grids by the Krylov Subspace Methods with the ILUT Preconditioner

    Sangback MA  

     
    PAPER-Numerical Analysis and Optimization

      Vol:
    E92-A No:5
      Page(s):
    1322-1330

    Given a sparse linear system, A x = b, we can solve the equivalent system P A PT y = P b, x = PT y, where P is a permutation matrix. It has been known that, for example, when P is the RCMK (Reverse Cuthill-Mckee) ordering permutation, the convergence rate of the Krylov subspace method combined with the ILU-type preconditioner is often enhanced, especially if the matrix A is highly nonsymmetric. In this paper we offer a reordering heuristic for accelerating the solution of large sparse linear systems by the Krylov subspace methods with the ILUT preconditioner. It is the LRB (Line Red/Black) ordering based on the well-known 2-point Red-Black ordering. We show that for some model-like PDE (partial differential equation)s the LRB ordered FDM (Finite Difference Method)/FEM (Finite Element Method) discretization matrices require much less fill-ins in the ILUT factorizations than those of the Natural ordering and the RCMK ordering and hence, produces a more accurate preconditioner, if a high level of fill-in is used. It implies that the LRB ordering could outperform the other two orderings combined with the ILUT preconditioned Krylov subspace method if the level of fill-in is high enough. We compare the performance of our heuristic with that of the RCMK (Reverse Cuthill-McKee) ordering. Our test matrices are obtained from various standard discretizations of two-dimensional and three-dimensional model-like PDEs on structured grids by the FDM or the FEM. We claim that for the resulting matrices the performance of our reordering strategy for the Krylov subspace method combined with the ILUT preconditioner is superior to that of RCMK ordering, when the proper number of fill-in was used for the ILUT. Also, while the RCMK ordering is known to have little advantage over the Natural ordering in the case of symmetric matrices, the LRB ordering still can improve the convergence rate, even if the matrices are symmetric.

  • Implementation Issues of Second-Order Cone Programming Approaches for Support Vector Machine Learning Problems

    Rameswar DEBNATH  Masakazu MURAMATSU  Haruhisa TAKAHASHI  

     
    PAPER-Neural Networks and Bioengineering

      Vol:
    E92-A No:4
      Page(s):
    1209-1222

    The core of the support vector machine (SVM) problem is a quadratic programming problem with a linear constraint and bounded variables. This problem can be transformed into the second order cone programming (SOCP) problems. An interior-point-method (IPM) can be designed for the SOCP problems in terms of storage requirements as well as computational complexity if the kernel matrix has low-rank. If the kernel matrix is not a low-rank matrix, it can be approximated by a low-rank positive semi-definite matrix, which in turn will be fed into the optimizer. In this paper we present two SOCP formulations for each SVM classification and regression problem. There are several search direction methods for implementing SOCPs. Our main goal is to find a better search direction for implementing the SOCP formulations of the SVM problems. Two popular search direction methods: HKM and AHO are tested analytically for the SVM problems, and efficiently implemented. The computational costs of each iteration of the HKM and AHO search direction methods are shown to be the same for the SVM problems. Thus, the training time depends on the number of IPM iterations. Our experimental results show that the HKM method converges faster than the AHO method. We also compare our results with the method proposed in Fine and Scheinberg (2001) that also exploits the low-rank of the kernel matrix, the state-of-the-art SVM optimization softwares SVMTorch and SVMlight. The proposed methods are also compared with Joachims 'Linear SVM' method on linear kernel.

  • A Linear Fractional Transform (LFT) Based Model for Interconnect Uncertainty

    Omar HAFIZ  Alexander MITEV  Janet Meiling WANG  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E92-A No:4
      Page(s):
    1148-1160

    As we scale toward nanometer technologies, the increase in interconnect parameter variations will bring significant performance variability. New design methodologies will emerge to facilitate construction of reliable systems from unreliable nanometer scale components. Such methodologies require new performance models which accurately capture the manufacturing realities. In this paper, we present a Linear Fractional Transform (LFT) based model for interconnect parametric uncertainty. The new model formulates the interconnect parametric uncertainty as a repeated scalar uncertainty structure. With the help of generalized Balanced Truncation Realization (BTR) and Linear Matrix Inequalities (LMI's), the porposed model reduces the order of the original interconnect network while preserves the stability. The LFT based new model even guarantees passivity if the BTR reduction is based on solutions to a pair of Linear Matrix Inequalities (LMI's) generated from Lur'e equations. In case of large number of uncertain parameters, the new model may be applied successively: the uncertain parameters are partitioned into groups, and with regard to each group, LFT based model is applied in turns.

  • Speech Clarity Index (Ψ): A Distance-Based Speech Quality Indicator and Recognition Rate Prediction for Dysarthric Speakers with Cerebral Palsy

    Prakasith KAYASITH  Thanaruk THEERAMUNKONG  

     
    PAPER-Speech and Hearing

      Vol:
    E92-D No:3
      Page(s):
    460-468

    It is a tedious and subjective task to measure severity of a dysarthria by manually evaluating his/her speech using available standard assessment methods based on human perception. This paper presents an automated approach to assess speech quality of a dysarthric speaker with cerebral palsy. With the consideration of two complementary factors, speech consistency and speech distinction, a speech quality indicator called speech clarity index (Ψ) is proposed as a measure of the speaker's ability to produce consistent speech signal for a certain word and distinguished speech signal for different words. As an application, it can be used to assess speech quality and forecast speech recognition rate of speech made by an individual dysarthric speaker before actual exhaustive implementation of an automatic speech recognition system for the speaker. The effectiveness of Ψ as a speech recognition rate predictor is evaluated by rank-order inconsistency, correlation coefficient, and root-mean-square of difference. The evaluations had been done by comparing its predicted recognition rates with ones predicted by the standard methods called the articulatory and intelligibility tests based on the two recognition systems (HMM and ANN). The results show that Ψ is a promising indicator for predicting recognition rate of dysarthric speech. All experiments had been done on speech corpus composed of speech data from eight normal speakers and eight dysarthric speakers.

  • Higher Order Differential Attack on 6-Round MISTY1

    Yukiyasu TSUNOO  Teruo SAITO  Hiroki NAKASHIMA  Maki SHIGERI  

     
    PAPER-Symmetric Cryptography

      Vol:
    E92-A No:1
      Page(s):
    3-10

    MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it has been recommended for Japanese e-Government ciphers by the CRYPTREC project. This paper reports a previously unknown higher order differential characteristic of 4-round MISTY1 with the FL functions. It also shows that a higher order differential attack that utilizes this newly discovered characteristic is successful against 6-round MISTY1 with the FL functions. This attack can recover a partial subkey with a data complexity of 253.7 and a computational complexity of 264.4, which is better than any previous cryptanalysis of MISTY1.

  • Voice Activity Detection Based on High Order Statistics and Online EM Algorithm

    David COURNAPEAU  Tatsuya KAWAHARA  

     
    PAPER-Speech and Hearing

      Vol:
    E91-D No:12
      Page(s):
    2854-2861

    A new online, unsupervised voice activity detection (VAD) method is proposed. The method is based on a feature derived from high-order statistics (HOS), enhanced by a second metric based on normalized autocorrelation peaks to improve its robustness to non-Gaussian noises. This feature is also oriented for discriminating between close-talk and far-field speech, thus providing a VAD method in the context of human-to-human interaction independent of the energy level. The classification is done by an online variation of the Expectation-Maximization (EM) algorithm, to track and adapt to noise variations in the speech signal. Performance of the proposed method is evaluated on an in-house data and on CENSREC-1-C, a publicly available database used for VAD in the context of automatic speech recognition (ASR). On both test sets, the proposed method outperforms a simple energy-based algorithm and is shown to be more robust against the change in speech sparsity, SNR variability and the noise type.

181-200hit(489hit)