bluuebunny/crossref_metadata_2025_split huggingface dataset:
A noise reduction method based on linear prediction analysis
Authors: Kawamura Arata , Fujii Kensaku , Itoh Yoshio , Fukui Yutaka 
Published: November 2002

AbstractThe linear prediction method works in such a way that the difference (prediction residual) between the objective signal and the output generated by making the objective signal a linear combination of the input signals is uncorrelated. Hence, in this linear prediction method, the linear predictor generates zero for the signal without correlation and recombines the voice for that with correlation. If this characteristic is used, recombined voice with suppressed noise can be obtained as the output of the linear predictor for voice with superposed white noise without correlation. Noise suppression can be realized by using this characteristic of the linear predictor. In this paper, a noise suppression method based on this linear prediction is discussed. According to this method, a noise suppression method without process delay can be realized. Also, no a priori information on the power spectrum of the noise is needed in this method. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 1–10, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10056
Back propagation learning with periodic chaos neurons
Authors: Onozaka Yoshio , Nakagawa Masahiro 
Published: November 2002

AbstractThis paper proposes a back propagation method using a periodic activation function for a hierarchical neural network and examines its learning capability. As a specific learning problem, the paper addresses the n‐bit parity problem and conducts a learning process by using a three‐layer neural network. The computer simulation results indicate an increased learning coefficient range achieving a 100% learning success rate with an improved speed of learning compared with a neural network model using a monotonic activation function. In addition, the new method lessens the influence of the initial value that is set at the beginning of a learning process, and reduces the degree of dependency on parameters. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 11–19, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1136
Noise‐robust speech analysis using system identification methods
Authors: Arima Yuki , Shimamura Tetsuya 
Published: November 2002

AbstractThis paper proposes a modified linear prediction method for speech analysis, using two system identification methods—the least‐square method and the instrument variable method—for the estimation of the coefficients of an all‐pole filter. Whereas the linear prediction method estimates the coefficients of all‐pole filters from speech signals, which are observed output signals, the system identification method estimates coefficients of all‐pole filters from observed output signals and the input signals. This paper derives a novel technique that estimates input signals from speech signals that are observed output signals with a high degree of accuracy and robustness with respect to added noise, by generating improved prediction error signals. The paper also shows that when voiced speech is to be analyzed, if input signals, which are an impulse chain, can be accurately estimated, the estimation of filter coefficients can yield a high degree of accuracy provided that the least‐square method is used, and that in this manner, the pitch period dependency can be removed. We also show that by applying the instrument variable method using an auxiliary model, the accuracy of estimation of filter coefficients in a noisy environment can be substantially improved while maintaining the properties of the least‐square method. The effectiveness of these system identification methods for speech analysis is demonstrated through computer simulations. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 20–32, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1137
Removal of impulse noise from highly corrupted images by using noise position information and directional information of image
Authors: Matsumoto Tetsuo , Taguchi Akira 
Published: November 2002

AbstractOne excellent method for restoration of images with superposed impulsive noise uses the position information of the impulsive noise for the pixels used for processing and of the processing point. This method consists of two steps. In Step 1, the impulsive noise existing in the image is detected and the noise position image is formed. In Step 2, by using the noise position image formed in Step 1, the filter processing is carried out on the pixels degraded by impulsive noise only with the pixels not affected by the impulsive noise. An excellent procedure for Step 2, using an average filter (PSA filter), has been proposed. However, in the method with an average filter, a uniform weight is provided on all pixels in the filter window. Therefore, if the generation probability of the impulsive noise is increased, the window size cannot be increased even if the filter window size should be increased. Also, an individual image has directionality specific to the image. This directionality is not taken into account in the filter processing. In the present paper, in order to resolve this problem, a PSWA filter is proposed for the filter processing in Step 2 by using the weighted average filter with weights considering the distance from the process point and the directionality of the image. In order to appropriately apply the proposed filter, there are two parameters (window size N and parameter κ) to be set. From experimental investigation, it is found that these two parameters do not depend on the type of the original image but only on the generation probability of the impulsive noise. Further, from the generation probability of the impulsive noise, the method for providing these two parameters is presented specifically. The effectiveness of the proposed method is confirmed through several processing examples. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 33–43, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1138
Some properties of a nonlinear combiner function: Linear complexity, mutual information, and correlation immunity
Authors: Shiraishi Yoshiaki , Morii Masakatu , Uyematsu Tomohiko , Sakaniwa Kohichi 
Published: November 2002

AbstractPseudo‐random number generators are used in spectrum‐spread communications and stream encryption, which is a shared‐key encryption scheme. In particular, the nonlinearly coupled pseudo‐random number generator (NLCRG), in which the outputs from multiple linear feedback shift registers (LFSRs) are nonlinearly coupled, is becoming increasingly important in practical applications because of its structural simplicity. However, even with the NLCRG, its properties, and especially the properties of its output system, are not yet fully understood. Previously, Moriyasu, Morii, and Kasahara proposed a dynamic random number generator (DRG), which is a subclass of NLCRGs, and attempted to analyze its output sequences. The present work provides a further analysis of the DRG; it also positions the DRG in the class of NLCRGs, and discusses the general properties of the NLCRG, such as linear complexity and mutual information. The paper also presents a simple method for constructing a nonlinear circuit with correlation immunity by using a DRG. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 44–56, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1139
A novel interpolation method for preserving image details by using the fuzzy technique
Authors: Kimura Tomoaki , Taguchi Akira , Murata Yutaka 
Published: November 2002

AbstractEnlargement processing of digital images is usually carried out by means of an interpolation function obtained by simplification of the sinc function. However, in such an interpolation method, restoration of the high‐frequency components lost in digitizing the images is not carried out at all. Hence, the enlargement causes blurring for images with many edges and detailed signals. For one‐dimensional signals, Carrato and colleagues have proposed an interpolation method in which the discontinuities of the step edge signals are preserved while other signals are linearly interpolated. In this method, no blurring occurs in the expansion processing of strong frames of the images. However, Carrato's method has the following problems. (1) Only the step edges in the image signals are taken into account so that consideration of the detailed signals is insufficient. (2) Extension of the one‐dimensional interpolation method given by Carrato to a two‐dimensional interpolation method has a problem in interpolation at the center of the lattice. In this paper, a method is proposed to accomplish improvement of Carrato's method. With regard to problem (1), the interpolation not only is effective for the step edge signals but also preserves the apex of the peak and valley signals. With regard to problem (2), improvement is planned by directly deriving the interpolation value from the original signals. The proposed interpolation processing is accomplished by describing the processing sequence by a rule. The proposed method consists of two sets of fuzzy reasoning. The proposed method and the conventional interpolation method are compared from the numerical and visual perspectives and the effectiveness of the proposed method is clarified. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 57–66, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1140
A method for generating complex finite sequences with a small peak sidelobe, using one period of a complex binary orthogonal sequence
Authors: Kirimoto Tetsuo , Mano Seiji 
Published: November 2002

AbstractFinite sequences with a small sidelobe level of an autocorrelation function are used for the pulse compression of radar signals and the synchronization of pulse communication circuits. This paper demonstrates that a finite sequence with a small peak sidelobe level can be generated through an algebraic approach from a period of a complex binary orthogonal sequence that is obtained by mapping M sequences on GF(2) to complex periodic sequences. The generated sequence is a complex finite sequence comprised of two complex numbers as its components, for which the code length can be given as 2k − 1, where k is a positive integer. By comparing the sidelobe characteristics of the resulting sequence with those of conventional real binary finite sequences for which the components are given as 1 and −1, this paper shows that the peak sidelobe level can be suppressed compared with conventional cases by rendering the finite sequence into a complex binary sequence. In the case of a code length of 7, for example, complex binary finite sequences with a peak sidelobe level lower than the real binary finite sequence shown by Barker by approximately 3.0 dB can be generated. In addition, radio frequency (RF) signals that are code‐modulated with the complex binary finite sequence are produced and their sidelobe characteristics are evaluated from signal waves that are obtained by correlating the signals, with the paper showing a high degree of agreement between experimental and calculated values. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 67–76, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1141
Image restoration by the family of signal adaptive parametric projection filters
Authors: Tanaka Akira , Imai Hideyuki , Miyakoshi Masaaki 
Published: November 2002

AbstractMany of the image restoration techniques can roughly be classified into two types: those that are formulated as an optimization problem with regard to the restored image and those that are formulated as an optimization problem with regard to the restoration operator. The former has the advantage that the local information on the image can easily be expressed in the optimization reference. A problem is that the closeness of the image needs to be evaluated indirectly in the observation image space instead of the original image space. On the other hand, in the latter the closeness of the image can be evaluated in the original image space. However, because the optimization reference used to obtain the appropriate restoration operator does not include the information on the individual images, it is difficult to express the local information on the image, in contrast to the former type. Based on such a background, the objective of this paper is to propose a restoration method that can evaluate the closeness of images in the original image space while the local information on the images can be used systematically, based on improvement of the optimization reference of the parametric projection filter family belonging to the latter. The effectiveness of the proposed method is verified by numerical examples. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 77–86, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1142
Stochastically fastest convergence BCGM‐OR algorithm with a guarantee value
Authors: Fukumoto Masahiro , Kanai Takeshi , Kubota Hajime , Tsujii Shigeo 
Published: November 2002

AbstractThe BCGM‐OR algorithm with a guaranteed value, which optimizes the number of iterations in the block‐orthogonal projection algorithm to which the conjugate gradient technique is applied and which guarantees the stability of operation, provides an upper bound on estimation error through the setting of a guaranteed value. As such, it has significantly improved the estimation accuracy without sacrificing the excellent tracking capacity of the block‐orthogonal projection algorithm. On the other hand, regarding the learning identification method in which the block size used in the block‐orthogonal projection algorithm is set to 1, a step gain (the stochastically fastest step gain) that maximizes the rate of convergence in addition to the setting of a guaranteed value has been demonstrated. Based on the stochastically fastest step gain on the learning identification method, this paper proposes a technique wherein a similar method is introduced into the BCGM‐OR algorithm with a guaranteed value and validates its effectiveness. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(3): 87–98, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1143
Operating characteristics of a superconducting fault current limiting transformer (SFCLT) and enhancement of electric power system stability
Authors: Kagawa Hiroaki , Hayakawa Naoki , Kashima Naoji , Nagaya Shigeo , Okubo Hitoshi 
Published: November 2002

AbstractWe have been investigating the feasibility of a superconducting fault current limiting transformer (SFCLT) with the functions of fault current suppression and system stability improvement. This paper discusses these functions with consideration of overvoltage and thermal characteristics of SFCLT, and their dependence on recovery time into superconducting state after the quench of SFCLT. Simulation results using EMTP suggested that SFCLT would be coordinated with the background power system under the appropriate superconducting recovery time. The operating parameters of SFCLT were also optimized in a simplified power transmission model system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 40–47, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10070
A study of switching techniques using serial and parallel resistors for power system stabilization
Authors: Kato Toshikazu , Yukita Kazuto , Goto Yasuyuki , Ichiyanagi Katsuhiro , Tabata Yasuto , Ogawa Shigeaki 
Published: November 2002

AbstractIn recent years, electric power systems have become more and more complicated and large‐scale. As a result, transient stability problems and voltage problems in power systems are being taken more seriously. In this paper, switching techniques using serial and parallel resistors for power system stabilization are proposed, and computer simulations and experiments using a transmission simulator were performed. The effectiveness of the stabilization was shown because a system swing was damped off by the on–off control of the series and parallel resistors. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 59–67, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10081
Switching of H∞ controller under constraints and decision of controller state at instance of the controller switching
Authors: Komatsu Hayato , Zanma Tadanao , Suzuki Tatsuya , Okuma Shigeru 
Published: November 2002

AbstractIn real control systems, certain constraints are placed on the input, state, and output values. If such constraints are violated, the system may become unstable, in a worst‐case scenario. One of the promising approaches to solving this problem is to switch the controller according to the state of the closed‐loop system. No useful design strategy for each controller, however, has yet been developed. In addition, the determination of the controller state at the instant of controller switching has not been investigated. First, this paper presents a new design methodology which merges the switching control and H∞ controller design into one design algorithm. Second, this paper presents a way of determining the controller state at the instant of controller switching. Finally, the proposed method is applied to force control of a one‐DOF manipulator in order to demonstrate the usefulness of the proposed method. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 68–75, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10082
Numerical investigation of the main factor promoting chaotic power swing in a single‐machine, infinite‐bus power system model with the AVR
Authors: Kita Toshihiro 
Published: November 2002

AbstractThis paper presents numerical results on bifurcations and chaotic behavior in a fundamental power system model, a single‐machine infinite‐bus system model with generator excitation control by the first‐order lag AVR. The numerical analysis mainly focuses on revealing the parameter value region where the chaotic behavior is observed. It is shown that the partially linearized model, which is derived by linearizing all of the nonlinear elements except the AVR limiter, exhibits similar bifurcations and chaos. Several simulation results indicate that the mechanisms producing the chaotic behaviors and the bifurcations are the same both in the linearized model and in the original single‐machine infinite‐bus system model for parameter value variation which does not move the equilibrium point from the reference point used for the linearization. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 21–28, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10090
Effect of electric field on viscoelastic properties of a disperse system in silicone gel
Authors: Hanaoka Ryoichi , Takata Shinzo , Nakazawa Yuichi , Fukami Tadashi , Sakurai Koji 
Published: November 2002

AbstractIn the electrorheological (ER) fluids of disperse systems, the poor dispersion stability of particles often limits the development of practical application of the fluids. This key problem can be settled by the chemical gelation of ER fluids. In the present study, a dimethylsilicone oil‐based gel containing the nonaqueous ER particles was newly created. The dynamic properties of viscoelasticity in the sample silicone gel were examined under applied DC electric fields of up to 2.0 kV/mm using a sinusoidal oscillating rheometer with low frequencies of 1 Hz or less. The particle behavior and the shearing deformation in the sample gel were also observed using a microscope, a CCD camera, and a color video monitor. When an electric field was applied to the sample gel, the gap between the electrodes was bridged by the chains of particles arranged in the direction of the electric field. Consequently, it is shown that the electroviscoelastic effect of the gel can be controlled by the electric field. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 1–9, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10098
A decentralized model following controllers for a class of large‐scale interconnected dynamical systems with uncertainties
Authors: Shigemaru Shinji , Wu Hansheng 
Published: November 2002

AbstractThe problem of decentralized robust tracking and model following is considered for a class of large‐scale interconnected systems with uncertainties. A class of linear decentralized state feedback controllers are proposed for robust tracking of dynamical signals in such a class of uncertain large‐scale systems. The proposed decentralized tracking controllers can guarantee that the tracking errors between each subsystem and local reference model are uniformly ultimately bounded. Moreover, we modify the linear controllers by introducing some nonlinear parts so that the tracking errors decrease asymptotically to zero in the presence of uncertain parameters and interconnection terms. Finally, an illustrative example is given to demonstrate the validity of our results. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 48–58, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10101
A method for voltage stability‐constrained optimal power flow (VSCOPF)
Authors: Okamoto Hiroshi , Tanabe Ryuya , Tada Yasuyuki , Sekine Yasuji 
Published: November 2002

AbstractThis paper presents a novel formulation for solving optimal power flow (OPF) problems with voltage stability constraints. The proposed Voltage Stability Constrained OPF (VSCOPF) formulation is based on voltage sensitivity with respect to total load demand representing the gradient of the P‐V curve at the operating point. In the formulation, voltage constraints are given by a set of equality constraints which must be satisfied by the voltage sensitivity. Since the voltage stability constraints retain a sparse matrix structure, the method based on the proposed OPF formulation may effectively solve large‐scale problems. The feasibility and effectiveness of the proposed method are demonstrated on test problems with 2‐, 49‐, and 2312‐bus systems. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 29–39, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10125
Stabilization control of multi‐machine power systems by adaptive power system stabilizer using frequency domain analysis
Authors: Senjyu Tomonobu , Yamashita Takahiro , Uezato Katsumi 
Published: November 2002

AbstractTo improve electric power system transient stability, synchronous generators are generally equipped with controllers such as AVR, PSS, and GOV. Fixed parameter controllers degrade control performance, since various oscillation modes occur depending on system conditions.This paper presents an adaptive power system stabilizer (PSS) using frequency domain analysis for improving the transient stability of a multimachine system. In the proposed method, first, the frequency components of the generator swings are detected by the FFT. The conventional PSS parameters are tuned online by a fuzzy controller and frequency domain analysis. We verify the proposed adaptive PSS using frequency domain analysis, which can damp the generator swings effectively. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 10–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10129