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[Keyword] AME(1195hit)

881-900hit(1195hit)

  • A Class Cohesion Metric Focusing on Cohesive-Part Size

    Hirohisa AMAN  Kenji YAMASAKI  Hiroyuki YAMADA  Matu-Tarow NODA  

     
    PAPER-Metrics, Test, and Maintenance

      Vol:
    E87-D No:4
      Page(s):
    838-848

    Cohesion is an important software attribute, and it is one of significant criteria for assessing object-oriented software quality. Although several metrics for measuring cohesion have been proposed, there is an aspect which has not been supported by those existing metrics, that is "cohesive-part size." This paper proposes a new metric focusing on "cohesive-part size," and evaluates it in both of qualitative and quantitative ways, with a mathematical framework and an experiment measuring some Java classes, respectively. Through those evaluations, the proposed metric is showed to be a reasonable metric, and not redundant one. It can collaborate with other existing metrics in measuring class cohesion, and will contribute to more accurate measurement.

  • Real-Time Frame-Layer Rate Control for Low Bit Rate Video over the Internet

    Yoon KIM  Jae-Young PYUN  Jae-Hwan JEONG  Sung-Jea KO  

     
    PAPER-Multimedia Communication

      Vol:
    E87-B No:3
      Page(s):
    598-604

    A real-time frame-layer rate control algorithm using sliding window method is proposed for low bit rate video coding over the Internet. The proposed rate control method performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. A new frame-layer rate-distortion model is derived, and a non-iterative optimization method is used for low computational complexity. In order to reduce the quality fluctuation, we use a sliding window scheme which does not require the pre-analysis process. Therefore, the proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performance than the existing TMN8 rate control method.

  • Joint Maximum Likelihood Approach to Frame Synchronization in Presence of Frequency Offset

    Young-Hoi KOO  Yong Hoon LEE  

     
    PAPER-Digital Signal Processing

      Vol:
    E87-A No:3
      Page(s):
    701-707

    This paper proposes new frame synchronizers that can achieve frame sync in the presence of a frequency offset. In particular, a maximum likelihood (ML) algorithm for joint frame synchronization and frequency estimation is developed for additive white Gaussian noise (AWGN) channels, then the result is extended to frequency selective channels. Computer simulations demonstrate that the proposed schemes can outperform existing methods when a frequency offset exists.

  • Analog Circuit Test Using Transfer Function Coefficient Estimates

    Zhen GUO  Jacob SAVIR  

     
    LETTER

      Vol:
    E87-D No:3
      Page(s):
    642-646

    Coefficient-based test (CBT) is introduced for detecting parametric faults in analog circuits. The method uses pseudo Monte-Carlo simulation and system identification tools to determine whether a given circuit under test (CUT) is faulty.

  • Nonlinear Observer Design via Approximate Normal Form: Ball and Beam System on a Vibrating Frame

    Juhoon BACK  Nam H. JO  Young I. SON  Hyungbo SHIM  Jin H. SEO  

     
    PAPER-Systems and Control

      Vol:
    E87-A No:3
      Page(s):
    716-724

    There exists a class of nonlinear systems which fail to have a well-defined relative degree but have a robust relative degree. We have removed the full relative degree assumption which the previous results required, and have provided a local state observer for nonlinear systems that have robust relative degree γ n and have detectability property in some sense. The proposed observer utilizes the coordinate change which transforms the system into an approximate normal form. Using the proposed method, we constructed an observer for the ball and beam system on a vibrating frame. Simulation results reveal that substantial improvement in the performance is achieved compared with other local observers.

  • Discrete Simulation of Reactive Flow with Lattice Gas Automata

    Kazuhiro YAMAMOTO  

     
    PAPER

      Vol:
    E87-D No:3
      Page(s):
    740-744

    Normally, flow field is described with governing equations, such as the Navier-Stokes equations. However, for complex flow including multiphase and reactive flow such as combustion, this approach may not be suitable. As an alternative approach, Lattice Gas Automata (LGA) has been used to simulate fluid with mesoscopic particles by assuming that space and time are discrete, and the physical quantities take only a finite set of values. In this study, the model for combustion simulation is proposed, with the reaction probability depending on the local temperature to simplify the chemical reaction. Here, counter-flow twin flames are simulated. In order to validate this approach, some results of non-reactive flow are presented, compared with those by solving Navier-Stokes equations.

  • A Thin-Film Glucose Biosensor Based on Hexamethyldisiloxane Plasma-Polymerized Film: Influence of Its Film Thickness on the Platinum Electrode

    Yoshihiro KASE  Hitoshi MUGURUMA  Atsunori HIRATSUKA  Isao KARUBE  

     
    PAPER-Nano-interface Controlled Electronic Devices

      Vol:
    E87-C No:2
      Page(s):
    142-147

    An amperometric thin-film glucose biosensor based on a plasma-polymerized film using hexamethyldisiloxane as the monomer is presented. The plasma-polymerized film, achieved in plasma in the vapor phase, offers a new alternative for use in the design of the electrode-enzyme interface of biosensors. The film shows promise of high sensor performance; namely, rapid sensor response, low noise, a wide dynamic range, reproducibility, and reduction in the effects of interfering materials such as ascorbic acid. In this study, we examined the usefulness of the hexamethyldisiloxane plasma-polymerized film and investigated how the thickness of the plasma-polymerized film on a platinum electrode affected sensor characteristics: the selectivity for hydrogen peroxide versus interfering agents, the sensor response due to enzymatic reaction, and oxygen depletion.

  • Efficient Coding Translation of GSM and G.729 Speech Coders across Mobile and IP Networks

    Shu-Min TSAI  Jia-Ching WANG  Jar-Ferr YANG  Jhing-Fa WANG  

     
    PAPER-Speech and Hearing

      Vol:
    E87-D No:2
      Page(s):
    444-452

    In this paper, we propose a speech coding translation scheme by transferring coding parameters between GSM half rate and G.729 coders. Compared to the conventional decode-then-encode (DTE) scheme, the proposed parameter conversions provide speech interoperability between mobile and IP networks with reducing computational complexity and coding delay. Simulation results show that the proposed methods can reduce about 30% computational load and coding delay acquired in the target encoders and achieve almost imperceptible degradation in performance.

  • Improvement of Wavelet Based Parameter Estimations of Nearly 1/f Processes

    Shigeo WADA  Nao ITO  

     
    PAPER-Digital Signal Processing

      Vol:
    E87-A No:2
      Page(s):
    417-423

    Nearly 1/f processes are known as important stochastic models for scale invariant data analysis in a number of fields. In this paper, two parameter estimation methods of nearly 1/f processes based on wavelets are proposed. The conventional method based on wavelet transform with EM algorithm does not give the reliable parameter estimation value when the data length is short. Moreover, the precise parameter value is not estimated when the spectrum gap exists in 1/f processes. First, in order to improve the accuracy of the estimation when the data length is short, a parameter estimation method based on wavelet transform with complementary sampling is proposed. Next, in order to reduce the effect of spectrum gap, a parameter estimation method based on wavelet packet with EM algorithm is proposed. Simulation results are given to verify the effectiveness of the proposed methods.

  • A Note on Transformations of Interactive Proofs that Preserve the Prover's Complexity

    Satoshi HADA  

     
    PAPER-Fundamental

      Vol:
    E87-A No:1
      Page(s):
    2-9

    Goldwasser and Sipser proved that every interactive proof system can be transformed into a public-coin one (a.k.a. an Arthur-Merlin game). Unfortunately, the applicability of their transformation to cryptography is limited because it does not preserve the computational complexity of the prover's strategy. Vadhan showed that this deficiency is inherent by constructing a promise problem Π with a private-coin interactive proof that cannot be transformed into an Arthur-Merlin game such that the new prover can be implemented in polynomial-time with oracle access to the original prover. However, the transformation formulated by Vadhan has a restriction, i.e., it does not allow the new prover and verifier to look at common input. This restriction is essential for the proof of Vadhan's negative result. This paper considers an unrestricted transformation where both the new prover and verifier are allowed to access and analyze common input. We show that an analogous negative result holds even in this unrestricted case under a non-standard computational assumption.

  • Robust Extended Kalman Filtering via Krein Space Estimation

    Tae Hoon LEE  Won Sang RA  Seung Hee JIN  Tae Sung YOON  Jin Bae PARK  

     
    PAPER-Systems and Control

      Vol:
    E87-A No:1
      Page(s):
    243-250

    A new robust extended Kalman filter is proposed for the discrete-time nonlinear systems with norm-bounded parameter uncertainties. After linearization of the nonlinear systems, the uncertainties described by the energy bounded constraint can be converted into an indefinite quadratic cost function to be minimized. The solution to the minimization problem is given by the extended Kalman filter derived in a Krein space, which leads to a robust version of the extended Kalman filter. Since the resulting robust filter has the same structure as a standard extended Kalman filter, the proposed filter can be readily designed by simply including the uncertainty terms in its formulas. The results of simulations are presented to demonstrate that the proposed filter achieves the robustness against parameter variation and performs better than the standard extended Kalman filter.

  • Fundamental Frequency Estimation for Noisy Speech Using Entropy-Weighted Periodic and Harmonic Features

    Yuichi ISHIMOTO  Kentaro ISHIZUKA  Kiyoaki AIKAWA  Masato AKAGI  

     
    PAPER-Speech and Hearing

      Vol:
    E87-D No:1
      Page(s):
    205-214

    This paper proposes a robust method for estimating the fundamental frequency (F0) in real environments. It is assumed that the spectral structure of real environmental noise varies momentarily and its energy does not distribute evenly in the time-frequency domain. Therefore, segmenting a spectrogram of speech mixed with environmental noise into narrow time-frequency regions will produce low-noise regions in which the signal-to-noise ratio is high. The proposed method estimates F0 from the periodic and harmonic features that are clearly observed in the low-noise regions. It first uses two kinds of spectrogram, one with high frequency resolution and another with high temporal resolution, to represent the periodic and harmonic features corresponding to F0. Next, the method segments these two kinds of feature plane into narrow time-frequency regions, and calculates the probability function of F0 for each region. It then utilizes the entropy of the probability function as weight to emphasize the probability function in the low-noise region and to enhance noise robustness. Finally, the probability functions are grouped in each time, and F0 is obtained as the frequency with the highest probability of the function. The experimental results showed that, in comparison with other approaches such as the cepstrum method and the autocorrelation method, the developed method can more robustly estimate F0s from speech in the presence of band-limited noise and car noise.

  • Facial Parts Recognition by Hierarchical Tracking from Motion Image and Its Application

    Takuma FUNAHASHI  Tsuyoshi YAMAGUCHI  Masafumi TOMINAGA  Hiroyasu KOSHIMIZU  

     
    PAPER-Face

      Vol:
    E87-D No:1
      Page(s):
    129-135

    Faces of a person performing freely in front of the camera can be captured in a sufficient resolution for facial parts recognition by the proposed camera system enhanced with a special PTZ camera. Head region, facial parts regions such as eyes and mouth and the borders of facial parts are extracted hierarchically by being guided by the irises and nostrils preliminarily extracted from the images of PTZ camera. In order to show the effectivity of this system, we proposed a possibility to generate the borders of facial parts of the face for the facial caricaturing and to introduce eye-contacting facial images which can eye-contact bilaterally with each other on the TV conference environment.

  • Calibration of Real Scenes for the Reconstruction of Dynamic Light Fields

    Ingo SCHOLZ  Joachim DENZLER  Heinrich NIEMANN  

     
    PAPER-Background Estimation

      Vol:
    E87-D No:1
      Page(s):
    42-49

    The classic light field and lumigraph are two well-known approaches to image-based rendering, and subsequently many new rendering techniques and representations have been proposed based on them. Nevertheless the main limitation remains that in almost all of them only static scenes are considered. In this contribution we describe a method for calibrating a scene which includes moving or deforming objects from multiple image sequences taken with a hand-held camera. For each image sequence the scene is assumed to be static, which allows the reconstruction of a conventional static light field. The dynamic light field is thus composed of multiple static light fields, each of which describes the state of the scene at a certain point in time. This allows not only the modeling of rigid moving objects, but any kind of motion including deformations. In order to facilitate the automatic calibration, some assumptions are made for the scene and input data, such as that the image sequences for each respective time step share one common camera pose and that only the minor part of the scene is actually in motion.

  • An Efficient Method for System-Level Exploration of Global Optimum in a Parameterized ASIP Design

    Yeong-Geol KIM  Tag-Gon KIM  

     
    LETTER-VLSI Design Technology and CAD

      Vol:
    E86-A No:12
      Page(s):
    3297-3302

    This paper proposes an efficient method for design space exploration of the global optimum configuration for parameterized ASIPs. The method not only guarantees the optimum configuration, but also provides robust speedup for a wide range of processor architectures such as SoC, ASIC as well as ASIP. The optimization procedure within this method takes a two-steps approach. Firstly, design parameters are partitioned into clusters of inter-dependent parameters using parameter dependency information. Secondly, parameters are optimized for each cluster, the results of which are merged for global optimum. In such optimization, inferior configurations are extensively pruned with a detailed optimality mapping between dependent parameters. Experimental results with mediabench applications show an optimization speedup of 4.1 times faster than the previous work on average, which is significant improvement for practical use.

  • An Efficient Analysis of Lossless and Lossy Discontinuities in Waveguide Using Hybrid Numerical Method

    Takeshi SHIRAISHI  Toshio NISHIKAWA  Kikuo WAKINO  Toshihide KITAZAWA  

     
    PAPER

      Vol:
    E86-C No:11
      Page(s):
    2184-2190

    A novel hybrid numerical method, which is based on the extended spectral domain approach combined with the mode-matching method, is applied to evaluate the scattering parameter of waveguide discontinuities. The formulation procedure utilizes the biorthogonal relation in the transformation, and the Green's functions in the spectral domain are obtained easily even in the inhomogeneous lossy regions. The present method does not include the approximate perturbational scheme, and it can evaluate accurately and stably the scattering parameters of either for the thin or thick obstacles made of the wide variety of materials, the lossless dielectrics to highly conductive media, in short computation time. The physical phenomena of transmission through the lossy obstacles are investigated by numerical computations. The results are compared with FEM where FEM computations are feasible, although the FEM computations cannot cover the whole performances of the present method. The good agreement is observed in the corresponding range. The matrix size in this method is smaller than that of other methods. Therefore, the present method is numerically efficient and it would be able to apply for the integrated evaluation of a successive discontinuity. The resonant characteristics of rectangular waveguide cavity are analyzed accurately taking the conductor losses into consideration.

  • A Row-Parallel Position Detector for High-Speed 3-D Camera Based on Light-Section Method

    Yusuke OIKE  Makoto IKEDA  Kunihiro ASADA  

     
    PAPER-Electronic Circuits

      Vol:
    E86-C No:11
      Page(s):
    2320-2328

    A high-speed 3-D camera has a future possibility of wide variety of application fields such as quick inspection of industrial components, observation of motion/destruction of a target object, and fast collision prevention. In this paper, a row-parallel position detector for a high-speed 3-D camera based on a light-section method is presented. In our row-parallel search method, the positions of activated pixels are quickly detected by a row-parallel search circuit in pixel and a row-parallel address acquisition of O(log N) cycles in N-pixel horizontal resolution. The architecture keeps high-speed position detection in high pixel resolution. We have designed and fabricated the prototype position sensor with a 12816 pixel array in 0.35 µm CMOS process. The measurement results show it achieves quick activated-position acquisition of 450 ns for "beyond-real-time" 3-D imaging and visual feedback. The high-speed position detection of the scanning sheet beam is demonstrated.

  • Enhanced Vibrato Analysis Using Parameter-Optimized Cubic Convolution

    Hee-Suk PANG  

     
    LETTER-Engineering Acoustics

      Vol:
    E86-A No:11
      Page(s):
    2887-2890

    Parameter-optimized cubic convolution is used to accurately analyze the pitch center, rate and extent of vibrato tones. We interpolate the time-tracing fundamental frequencies of vibrato tones using parametric cubic convolution, and analytically estimate the positions and values of the extrema, which are used to analyze the characteristics of the vibrato. The optimal values of α, the parameter of the interpolation kernel, are also shown as a function of the normalized vibrato rates.

  • Equivalent Circuit Model of InAlAs/InGaAs/InP Heterostructure Metal-Semiconductor-Metal Photodetectors

    Koichi IIYAMA  Junya ASHIDA  Akira TAKEMOTO  Saburo TAKAMIYA  

     
    PAPER-Lasers, Quantum Electronics

      Vol:
    E86-C No:11
      Page(s):
    2278-2282

    One-dimentional equivalent circuit model of a heterostructure InAlAs/InGaAs/InP metal-semiconductor-metal photodetector is discussed. In this photodetector, InGaAs is used as an optical absorption layer and the InAlAs is used for Schottky barrier enhanement. The measured S11 parameter deviates from equi-resistance lines on the Smith chart, indicating the equivalent circuit is different from the conventional equivalent circuit using a series resistance, a depletion region capacitance and a depletion region resistance. The difference is due to band discontinuity at the heterojunctions, and we propose a equivalent circuit taking account of the band discontinuity. The band discontinuity is expressed by parallel combination of a resistance and a capacitance. The measured S11 parameter can be fitted well with the calculated S11 parameter from the proposed equivalent circuit, and we can successfully extract the device parameters from the fitted curve.

  • Scene-Adaptive Frame-Layer Rate Control for Low Bit Rate Video

    Jae-Young PYUN  Yoon KIM  Sung-Jea KO  HwangJun SONG  

     
    LETTER-Source Coding/Image Processing

      Vol:
    E86-A No:10
      Page(s):
    2618-2622

    Rate control regulates the coded bit stream to satisfy certain given bit rate condition while maintaining the quality of coded video. However, most existing rate control algorithms for low bit rate video can not handle scene change properly, so visual quality is consequently worsened. The test model TMN8 of H.263+ can be forced to skip frames after an abrupt scene change. In this letter, we propose a new frame-layer rate control which allocates bits to frames and controls the frame skipping adaptively based on the pre-analysis of future frames. Experimental results show that the proposed control method provides an effective alternative to existing frame skipping methods causing the motion jerkiness and quality degradation.

881-900hit(1195hit)