bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral peak enhancement methods for 1‐D and 2‐D signals and their applications
Authors: Shimamura Tetsuya , Suzuki Jouji 
Published: July 2007

AbstractIn this paper, we propose a method to enhance the maximum spectral peaks of signal components corrupted by noise for one‐ and two‐dimensional (1‐D and 2‐D) signals under the condition that no a priori information is given. This method does not use a conventional filter where the passband is one and the stopband is zero but uses a filter where the spectral characteristics of the signal to be extracted from the input signal are the desired characteristics; that is, the filter is dependent on the input signal. For 1‐D signals, we demonstrate that the signal components can be satisfactorily enhanced by iterative processing using the fast Fourier transform (FFT) given an “autoregressive (AR signal + white noise signal” and a “harmonic signal + white noise signal.” For 2‐D signals, the amount of computation is decreased significantly and good spectral enhancement is possible compared to conventional methods. Furthermore, the possible application of this method to the design of narrowband plane wave detection filters, which are difficult to design using conventional methods, is presented.
A parallel processing method for implementing the RSA cryptosystem
Authors: Iwamura Keiichi , Matsumoto Tsutomu , Imai Hideki 
Published: July 2007

AbstractModular multiplication: R = A · B mod N (where A, B, N, and R are integers) is an essential operation used in public‐key cryptosystems such as RSA, El Gamal, and Rabin. Thus, if high‐speed modular multiplication circuits can be constructed, these cryptosystems can operate at high speeds. In this paper, we show how to construct, with a high‐speed modular multiplication circuit which employs parallel processing methods using systolic arrays, a circuit which performs modular exponentiation by repeated modular multiplication. In particular, we demonstrate its validity by using the RSA scheme as a first concrete example. Since a circuit using the method of this paper as its construction rule has simple and regular structure, it provides an optimal construction of a highspeed RSA chip in VLSI. The method is also applicable for a simple implementation of the RSA scheme with small‐sized chips. In this case, the number of chips needed by this method (the circuit size) allows the practical realization of proportionately higher speeds. Flexibility can be achieved for a change in the number of key bits by a corresponding increase or decrease in the number of chips.
An approximation method of group delay characteristics of 1‐D and 2‐D discrete time systems
Authors: Ino Kazuhiro , Sakai Masayoshi , Hamada Nozomu 
Published: July 2007

AbstractIn the fields of signal transmission and its processing, compensation of phase or group delay distortion is an important problem.This paper proposes an approximation method of group delay characteristic of one‐dimensional (1‐D) and 2‐D discrete‐time systems using an extended equation error function as its performance index. Since the phase approximation problem is inherently nonlinear, some iterative approaches have been proposed. Its disadvantage is in the increase of the amount of computation.Another method to transform group delay approximation problem to power spectrum approximation problem is presented. This indirect approach leads to the minimum squared error problem which is easily solved but does not yield a satisfactory result.In the first part of this paper, the 1‐D group delay approximation problem is formulated to a linear problem in group delay domain. Then we apply the quasi‐least mean squared method to it. In the latter part of this paper, the 1‐D method is extended to the 2‐D group delay approximation problem. Some examples are shown to verify the effectiveness of the method.
A stable algorithm for block adaptive filtering
Authors: Oishi Kunio , Fukumoto Masahiro , Kubota Hajime 
Published: July 2007

AbstractTwo methods have been proposed for calculating the block orthogonal projection algorithm using the Moore‐Penrose generalized inverse matrix. One is the conjugate gradient method, and the other is the block adaptive algorithm composed of the Gram‐Schmidt orthogonalization and the learning identification. Both computation methods are suited to the high‐speed estimation of the optimal coefficients with a small computational complexity. However, the operation may become very unstable due to the effects of observation error, quantization error, and other factors.This paper proposes a method of realizing the block orthogonal projection algorithm with the learning identification, where the orthogonal basis of the space spun by the state matrix in the block adaptive filter is used as the direction of modification. A feature of this method is that the orthogonal basis is calculated using the orthogonal projection matrix. Computer simulation shows that the proposed adaptive algorithm realizes a very stable operation without being affected by either the quantization error, the operational error, or the observation noise.
A simple derivation of the riccati equation for H∞ control via state feedback
Authors: Shimizu Kiyotaka , Hanabusa Masataka , Tamura Taro 
Published: July 2007

AbstractA derivation of the Riccati equation giving a necessary and sufficient condition for H∞ control by state feedback is presented. It is proved by solving the LQ‐max problem which is equivalent to the satisfaction condition (H∞ norm constraint condition) such that the uniform norm ∣Tvz∣ of a transfer operator T from the disturbance v to the controlled output z is kept below a prescribed γ.Based on the state space representation, the proof is achieved by extending optimal regulator theory. While normal proofs are based fundamentally on the analysis of the H∞ norm in the frequency domain, it is performed fully in the time domain. This paper provides a direct and self‐contained proof.
Coupled‐mode theory of SAW periodic structures
Authors: Suzuki Yuji , Takeuchi Masao , Nakamura Kiyoshi , Hirota Kazuhiro 
Published: July 2007

AbstractThe coupled‐mode theory is extremely useful for analysis of such periodic structures as grating reflector, resonator, and unidirectional transducer making use of electrode reflection as important constituent elements for the SAW devices. Here, the coupled‐mode equations describing the transduction characteristics of the inter‐digital electrode transducer (IDT) are derived directly by the perturbation theory. In addition, the parameters for the coupled‐mode equations are presented for quartz, LiTaO3and LiNbO3substrates.Next, based on the coupled‐mode equations, the relationship among the quantities of the electrical port and two acoustic ports of the IDT is derived. The entire periodic structure was represented by a simple distributed equivalent circuit. The equivalent circuit analysis method is described for the analysis of the device characteristics. To show the usefulness of the present method, a backward‐wave type trapped‐energy SAW resonator and the resonator coupled filter are analyzed.
Branch‐and‐bound placement for building block layout
Authors: Onodera Hidetoshi , Taniguchi Yo , Tamaru Keikichi 
Published: July 2007

AbstractThis paper proposes a placement technique based on the branch‐and‐bound method for the block placement problem in building block layout. In contrast to a traditional method of finding an approximate solution by a heuristic approach, the proposed method seeks a solution from all possible placements.To find the solution efficiently, the branch‐and‐bound operation suited to the placement problem is devised. The proposed method positively considers the constraints imposed on routing length and placement configuration since they could be utilized for restricting the solution space. When the constraints are stronger, the solution space is more restricted, which helps to complete the search of the solution in a short time.By an experimental investigation concerning the number of blocks that can be handled at a time, it is seen that almost six blocks can be handled if there is no constraint. When the number of blocks exceeds this limit, the circuit is decomposed in a hierarchical way and the branch‐and‐bound placement is applied to each subproblem until the layout of the whole circuit is determined. The proposed placement method is applied to the standard benchmark circuit for building block layout, and it is seen that the result by the proposed method is better than or very close to the best result reported so far.
A measure for selecting source signals used in quality assessment of coded music signals
Authors: Takahashi Akira , Nagabuchi Hiromi 
Published: July 2007

AbstractIn order to establish the quality assessment method for the wideband high‐quality acoustic telecommunication, the selection of the source signal is one of the important issues. The effect of the source signal used in the quality assessment on the subjective quality must be analyzed, and the measure for the selection of the source signals must be developed based on the result of analysis.This paper considers the 20‐kHz band music signal and a measure for selecting the source signal is proposed to be used in the assessment of the coding distortion, which is one of the deteriorating factors for the communication quality. The effectiveness of the measure is demonstrated. As the first step, the “noisiness of the mid‐band signal,” the “flatness of spectrum envelop” and the “harmonicity of spectrum” are considered as the features that affect the subjective assessment score of the coded music signal. A measure for selecting the source signal based on those feature parameters is proposed and the parameters are optimized by the training data. The assessment experiment is conducted using the source signal recorded in the acoustic signal set (SQAM‐CD) recommended by CCIR, and the effectiveness of the proposed selection measure is verified when it is applied to the unknown data. It is also shown that the performance of the assessment object is more accurately evaluated using the proposed selection measure than in the case where the source signals are selected at random.
Fast stabilized adaptive algorithm for IIR bandpass/notch filters for a single sinusoid detection
Authors: Li Shang , Takahashi Nobuaki , Takebe Tsuyoshi 
Published: July 2007

AbstractIn this paper, a new algorithm for the detection of a single sinusoid corrupted by Gaussian noise using IIR adaptive bandpass/notch filter is presented. As the first step, the relation between the convergence speed and the filter Q‐factor in IIR adaptive bandpass filter is analyzed. Based on the result of analysis, an algorithm is derived in which the filter Q‐factor and the adaptive control signal generator Q‐factor are made continuously variable so that they are inversely proportional to the distance between the filter center frequency f0 and the frequency f of the sinusoid to be detected. This makes both the convergence speed of f0 and f and the resolution high. Then it is found that limiting the maximum amplitude response of the adaptive control signal generator to a value proportional to sin 2πf can suppress the coefficient fluctuation after convergence effectively. By this approach, an IIR adaptive filter with a high Q can easily be realized. As the next step, an additional high‐speed and highly stable adaptive algorithm is proposed in which the step size of the filter coefficient update is made to vary inversely with the filter Q‐factor. A realization of the IIR adaptive notch filter is also presented. Finally, the usefulness of the proposed adaptive algorithm is verified by a computer simulation.
Minimum steady‐state variance control
Authors: Kisaka Masashi 
Published: July 2007

AbstractThis paper discusses the design of the digital controller, which minimizes the steady‐state variance of the output when a known external disturbance is applied to a control system. The first‐order control object is considered as an example, and the cases of colored external noise and the sinusoidal disturbance are discussed. It is shown through discussions that the steady‐state variance of the output can be represented in the form of the Lyapunov equation. It is pointed out that if the controller coefficient is found to minimize the function, the steady‐state variance can be minimized.Using the proposed method, the order of the controller can be determined independently of the order of the controlled object as long as the system can be stabilized. For the motor control system containing an analog band‐elimination filter, for example, it is possible to determine the coefficient of the digital PID controller to minimize the positioning error.
Analysis of weak nonlinear regulator problems with the solution confined to the integral manifold
Authors: Eguchi Masayoshi , Shidama Yasunari , Yamaura Hiroo , Cai Dawei 
Published: July 2007

AbstractThis paper uses the fixed‐point theorem to generate a set of sufficient conditions which confine the solutions of weak nonlinear differential equations to some low‐order stable integral manifold. Furthermore, it is shown that these conditions can be weakened to a great extent if the initial values of the differential equations are confined to a bounded region.A method is proposed for finding the integral manifold in an analytic form such as a Fourier series and a new calculation algorithm which applies the Newton method and other techniques. Next, the obtained results are applied to weak nonlinear optimal regulator problems and sufficient conditions are derived for the existence of a nonlinear feedback control law which meets the necessary conditions for optimality. Simulations using the algorithm exhibited favorable results.
A method for solving reliability optimization problem with incomplete FDS by Fuzzy multiobjective 0–1 linear programming
Authors: Sasaki Masato , Gen Mitsuo 
Published: July 2007

AbstractIn general, inevitably the particular structure called generalized upper bounding (GUB) occurs when transforming the reliability optimization problem such as optimal unit selection and redundant allocation. These are formulated as the nonlinear integer programming problem and transformed to the 0‐1 linear programming problem.Recently, a method for solving the fuzzy multi‐objective 0‐1 linear programming (0‐1 FMOLP) problem which extends the efficient method considering the GUB structure to the more general MOLP problem is proposed. Also, the method is extended to deal with the fuzziness of the goal value toward the objective function. However, this method is not considered for the break‐down of the fault‐detecting and switching (FDS) device; thus, it does not sufficiently cope with the real world's reliability optimization problem.From these viewpoints, an algorithm is proposed for solving the optimal redundant unit selection problem that optimizes the system reliability with imperfect FDS device by fuzzy 0–1 MOLP. The method proposed here considers the fuzziness of the decisionmaker (DM) toward the goal value of each objective function by introducing the fuzzy goal. Further, this method enables the DM to determine the most satisfactory solution to the attainment of each goal value of the objective function and constraint and can cope with the realistic optimal design of the system reliability problems.
Protection against trojan horses by source code analysis
Authors: Saito Tadao , Aida Hitoshi , Kawaguchi Youji 
Published: July 2007

AbstractThe technology of security in computer networks has far‐reaching implications. In this paper, assuming a UNIX network system, which is the most popular currently, we enumerate the threats against security and classify the problems. Among the problems so defined, we consider particularly the Trojan horse problem, which is important when a program is received from the outside; and we propose a method of protection against Trojan horses. In the proposed protection method, objects which have been modified by the source program are extracted and are compared with a previously prepared list (the condition list) of objects which should not have been modified. In this method, verification of the security of the program needs to be done only at the time of its installation, so there is no loss in efficiency of performance at run time. Also, we can prevent security violations which cannot be regulated by controlling access and flow. In the proposed method, the major problem is determining the extent to which altered objects can be detected. In this regard, we perform soine experiments on the free software X11R4 and TeX. Finally, based on the results of the experiments, we evaluate the proposed protection method on the security of programs imported from the outside.
Chip compaction method with automatic jog insertion
Authors: Yamamoto Wataru , Awashima Toru , Sato Masao , Ohtsuki Tatsuo 
Published: July 2007

AbstractThe realization of an electronic circuit in the smallest possible area is the key to a successful LSI design. As a result, research on one‐dimensional compaction methods has been active on reducing the area of a given IC layout. Further, it is desirable to reduce the area with jogs in wiring patterns.Compaction methods have been proposed that automatically add jogs effectively in the channel routing region for area reductions. These methods include the plane‐sweep method developed in computational geometry and are fast and flexible enough to adapt to complex design rules. However, it is not only very difficult but inefficient to apply these methods to the entire chip area including functional blocks.This paper proposes a chip compaction method which inserts jogs while maintaining the advantages of the compaction methods based on the plane‐sweep method. The proposed method is based on the shortest path search under a constraint graph and is capable of dealing efficiently with functional blocks. Experimental results will show the effectiveness of the method.
Multivariate analysis at switching points between different types of muscle contractions
Authors: Kiryu Tohru , Satoh Hitoshi , Saitoh Yoshiaki 
Published: July 2007

AbstractThe biomedical signal often is affected by the anatomical structure, the method of measurement and the analytical approach which makes it difficult to determine the feature of the change only by observing the signal. Then it is important to analyze the biological activity comprehensively from the biomedical signals measured through multiple channels or from the multiple parameters estimated from a single biomedical signal.From the viewpoint of the analysis of a long‐term biomedical signal, one of the most important indices is the switching point of biological activity. In the analysis of the economical indices, the prediction of earthquakes, and the weather forecasts, it is usual in practice to estimate the switching point for the trend from the time‐series data.The goal of this study is to estimate the switching point of the behavior of the biological system from the multiple time‐series. The statistical properties of the switching point are investigated as the preliminary study. Four evaluation parameters are estimated from the surface electromyogram of the tibialis anterior muscle and the eigenvalue time‐series is determined from the multiple evaluation parameter time‐series by Karhunen‐Loéve (KL) expansion. The results showed that two eigenvalues λ1, and λ2 approached each other near the switching point between the different muscle contractions and only λ1 exhibited a large value at other phases. The distribution of the principal components also showed a change near the switching point. The forementioned tendency was observed in approximately 55 percent of five trials for 10 subjects.
The structure of elimination‐type algorithms for a class of fixed‐point problems on graphs
Authors: Tamai Tetsuo 
Published: July 2007

AbstractIt is known that many kinds of problems, including as typical examples the shortest path problem studied in the Operations Research and the dataflow analysis problem treated in the compiler technique, can be formulated uniformly as a fixed‐point problem on graphs.This paper deals with elimination‐type algorithms for solving such problems. First, a unified formulation of the problem is presented and then two categories of elimination‐type solution methods are identified and classified by the elimination order and its meaning on graphs. One class is characterized as maintaining a spanning tree and the other as maintaining a maximal acyclic graph in the upper triangular matrix. The former is efficient specifically when applied to reducible graphs. This approach is reexamined from a new viewpoint. The latter is a method newly proposed by the authors and is applicable to general irreducible graphs and has practical features.
A 2‐D IIR neural hybrid filter for image processing
Authors: Muneyasu Mitsuji , Tsujii Satoshi , Hinamoto Takao 
Published: July 2007

AbstractA two‐dimensional (2‐D) IIR neural hybrid (2DINH) filter is proposed for image processing. This 2DINH filter consists of the cascade connection of a 2‐D IIR linear filter followed by a neural filter. The proposed filter can be applied to smoothing for the images corrupted with Gaussian noise and/or impulsive noise and to edge detection for the images corrupted with Gaussian noise.The parameters of a neural filter are adjustable by a learning algorithm to adapt itself to the property of an image to be processed. Finally, some examples are given to illustrate the utility of the proposed filter.
Two‐terminal nets via minimization through dynamic programming for partitioning of terminals
Authors: Fujiyoshi Kunihiro , Kajitani Yoji 
Published: July 2007

AbstractIn the routing in VLSI and printed circuit board (PCB) using the multilayered board, a routing technique is considered to reduce the number of vias produced in the routing. It is shown that the problem to determine the routing and layer assignment, to minimize the number of vias without considering the constraints of the line width and the line spacing, is NP‐hard even if the net is restricted to be the two‐terminal net. On the other hand, the following polynomial‐time algorithm is proposed.Let the number of continuous intervals of terminals not containing the local net that can cover all terminals be δ (by local net is meant a net with both ends in the same interval). Then there exists a polynomial‐time algorithm when δ is 2 and the number of layers k is a constant or when k is 2 and δ is a constant.This paper proposes a polynomial algorithm based on the dynamic programming which can handle both δ and k as parameters. Furthermore, a method also is proposed in which the partition into intervals is arbitrary and the local net can be contained. In addition, the total number I of the local nets can be handled as a parameter; I and δ are in a trade‐off relation. A method is discussed which solves the problem with minimum complexity in terms of the time estimated by the proposed method.
Identification of impulse responses by wavelet transformation
Authors: Maeda Hajime , Kitagawa Takashi , Kodama Shinzo 
Published: July 2007

AbstractThe wavelet transform is a signal transformation technique in which the information in the time and frequency domains can be obtained simultaneously within the range of the uncertainty principle. In this paper, identification of impulse responses is performed using the wavelet transform.First, the system identification problem is studied by using the wavelet theory. It is shown by a numerical example that the high‐frequency components of the signal can be separated in the time domain from the noise provided the weighting function is chosen suitably. Finally, the role of the weighting function is discussed theoretically.