bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral line estimation using complex coefficient prefilters
Authors: Shimamura Tetsuya , Takahashi Shin‐Ichi , Sakaguchi Naoya 
Published: July 2007

AbstractA spectral line estimation method is proposed which improves the resolution of the two nearby sinusoidal frequencies. In contrast to the conventional method in which the decimation operation is applied to the signal passing through the real coefficient bandpass prefilter, the present method carries out the process by means of the complex coefficient prefilter. By means of this technique, numerous problems to be resolved under the condition that relatively few data are given under a low SN ratio, such as the problem of initial phase dependence and the problem of accurate spectral estimation at a low‐ or high‐frequency region, can be overcome.This paper presents a method in which the decimated signals by a decimation operation are used effectively. The method particularly improves the estimation capability in the case with fewer data. Finally, by means of a simulation, the effectiveness of these methods is proven. It is shown that the estimation accuracy is improved significantly as long as the amount of operations is similar to that for the conventional method using the real coefficient prefilter.
Computationally efficient determination of a polynomial discriminate function using the AIC and its systolic array implementation
Authors: Iiguni Youji , Sakai Hideaki , Tokumaru Hidekatsu 
Published: July 2007

AbstractThis paper presents a computationally efficient algorithm for selecting the terms of the polynomial discriminate function (PDF) by means of the Akaike information criterion (AIC). The Levinson‐type algorithms is introduced for a computationally efficient determination of the PDF and a simple computation of the AIC. Our method is applied to seven segment and vowel recognition to show its usefulness. In an actual application, a parallel information processing is indispensable to reduction of computation time. Thus, systolic array for computing the PDF that is suitable for VLSI implementation is shown.
Approximate realization of identity mappings by three‐layer neural networks
Authors: Funahashi Ken‐Ichi 
Published: July 2007

AbstractRecently, applications of neural networks to information compression, e.g., image data compression, have been studied. This paper discusses these problems from a viewpoint of the approximate realization of identity mappings by the use of three‐layer neural networks.The relationship between statistical properties of data, hidden units number and the infimum of approximation error also is clarified theoretically by the study of the relation with principal component analysis in the case in which the hidden layer generally has nonlinear units. As a result, it is proved that the capability of information compression by three‐layer networks does not exceed the capability of the K‐L transformation method. Moreover, the phenomenon of generalization in this case is explained theoretically.
Trellis coded modulation for additive impulsive noise
Authors: Ogiwara Haruo , Ootaki Ryuichi 
Published: July 2007

AbstractThis paper discusses the situation where the trellis coded modulation (TCM) is applied to the digital subscriber loop (DSL) using a balanced pair cable, and examines the effectiveness. The usual error‐correcting code cannot be applied successfully to the balanced pair since the loss increases with the increase of the transmission bandwidth. When TCM is applied, on the other hand, the transmission performance for the Gaussian noise can be improved without increasing the transmission bandwidth. The major factor deteriorating the performance in DSL, however, is the impulsive noise. From such a viewpoint, this paper examined the effectiveness of TCM for the impulsive noise.First, the probability density of the impulsive noise is derived from the measurement of the exiting DSL, and the channel capacity is calculated. It is shown that it is necessary and sufficient to double the transmitting symbols and to assign the produced redundancy to the error‐correction. This is the same as the known result for the Gaussian noise, but the coding gain by the ideal coding is 18 dB, which is larger than in the case of the Gaussian noise. The coding gain of 9 dB is obtained by the simulation using the 8‐state convolutional code, which is larger than 4 dB in the case of the Gaussian noise. The reason for this improvement is discussed from the viewpoint of the probability distribution of the noise and the signal mapping in the multidimensional signal space.
Adaptive arrays using a complex learning algorithm
Authors: Kobayashi Akira , Yahagi Takashi 
Published: July 2007

AbstractThe demand for the mobile communications is increasing every year, and TV and automobile telephone by satellite communication are expected to find wider applications. If individuals are to carry communication equipment, then the equipment must be small size, lightweight and highly efficient. To realize antennas which must also be of small size, lightweight and highly efficient. For such equipment it is desirable to employ the adaptive array with phase control.Conventionally, the LMS algorithm has been applied frequently in the design of the adaptive array. However, the authors believe that the learning algorithm is better suited to the adaptive array because of its higher convergence speed and the clear specification of the convergence condition.This paper extends the real‐type learning algorithm to the complex‐type learning algorithm. The convergence condition for the algorithm is derived, and the result of the application of the method to the adaptive array is shown. A method of deriving the reference wave also is presented which is less affected by the input signal variation and is suited to the adaptive array with only the phase control. Using the proposed complex learning algorithm and the new reference wave, the phase‐controlled adaptive array is designed. A satisfactory result is obtained by simulation.
A realization of interpolator with the coefficients of the power of two
Authors: Todaka Chiaki , Kambayashi Noriyoshi 
Published: July 2007

AbstractThis paper is aimed at the reduction of the hardware complexity and the computational complexity in the interpolation processing. A construction and design method for the interpolator is shown where only the coefficients of the power of two are employed. The interpolator is composed of the cascade connection of a passband compensatory filter, a zero‐interpolator, and a stopband forming filter. Since no multiplier is used in the proposed construction, zero coefficient sensitivity as well as a high‐speed operation are realized. FIR or IIR construction is used for the passband compensatory filter, and the stopband forming filter is constructed by a cascade connection of RRS.The design procedure for the interpolation is as follows. The linear programming is applied first to design the stopband forming filter. Then the passband compensatory filter is designed by the indirect exhaustive method or the least‐square method. It is shown through design examples that the proposed interpolator is useful in reducing the hardware complexity and the computational complexity.
Orthogonal periodic sequences with two complex numbers derived from M‐sequences
Authors: Kirimoto Tetsuo , Oh‐Hashi Yoshimasa , Hotta Takashi 
Published: July 2007

AbstractThe periodic sequence for which the sidelobe of the autocorrelation function is zero is called an orthogonal sequence. The orthogonal sequence is applied to various problems such as synchronization of communication and radar ranging. As a general method to generate the orthogonal sequence, the method to form the discrete‐Fourier transform of the periodic sequence with a constant amplitude is known.This paper proposes a method of generating the orthogonal sequence with an element of the sequence being composed of two complex numbers (orthogonal periodic sequence with two complex numbers). The method does not use the discrete‐Fourier transform, but maps the elements of the M‐sequence on Galois field GF(2) to complex numbers. Then the properties of the orthogonal sequence are discussed from the geometrical viewpoint and the range for which the orthogonal periodic sequence with two complex numbers exists is indicated.
A study on coding of fractal curves
Authors: Katsuno Shin'Ichi , Yamasaki Issei 
Published: July 2007

AbstractThis paper describes the feature of codings for fractal curves. Here the two basic coding methods, the chain coding and the polygonal approximation, are examined. The ratio of the number of chain codes to the number of line segments for fractal curves is derived as a function of the triple quantities: the maximum allowable error; the line length of polygonal approximation; and the coefficient which is determined by the method of fractal curve generation. The ratio of the maximum allowable error to the line about the polygonal approximation of the artificial fractal curve can be derived from its fractal dimension.
A synthesis of active RC multipassband filters
Authors: Watanabe Hiromichi , Kikuchi Hisakazu 
Published: July 2007

AbstractThis paper presents a synthesis method for active RC filters with multiple pass‐bands. The synthesis procedure is based on a signal‐flow graph representation and frequency transformation applied to a passive LCR filter. It should be noticed that an active RC filter with multiple passbands is amenable to the finite gainband product effects of an operational amplifier. This is really true if adjacent passbands are close. Hence an effective technique is developed for reducing the finite GB product effects. An experimental result concerning the two‐passband filter derived from a third‐order Chebyshev filter also is included.
Realization of resistively matched three‐ports and the suppression of multiple reflections traveling on branched transmission lines
Authors: Sakagami Iwata 
Published: July 2007

AbstractIn the mutual interconnects between the printed transmission lines containing highspeed logic devices, impedance mismatch causes multiple reflections of the pulse waveform so that false triggerings of logic device occur. This paper describes suppression of multiple reflections on a three‐port single‐branched transmission line which divides a signal into two directions.First, a resistively matched three‐port is proposed in which all the ports are matched to arbitrary loads. Its realization by the scattering matrix is shown. If negative branching resistors are included, this circuit can always be realized, although a negative resistor is not easily conceived. Hence, the range of the load resistance is found which is realizable with a nonnegative branching resistor. This range is shown graphically.Next, three transmission lines with arbitrary characteristic impedances are connected to the resistively matched three‐port. This is used as a three‐port, single‐branched transmission line. This circuit supports an ideal condition in which a signal is sent out to the output side without reduction of the amplitude level and without causing any multiple reflection for an incident voltage wave. However, this ideal condition has two cases: one requiring a negative branching resistor, and another requiring an infinite characteristic impedance. Neither can be realized easily. Hence, realizable element values closest to the ideal condition are selected for which the multiple reflection is studied. In comparison with the case without a resistive matched three‐port, the effectiveness of suppression of the multiple reflection is superior if the latter is used.
Schematic description language for a hardware top‐down design approach
Authors: Kobayashi Kazuo , Wakabayashi Haruo , Wakimura Yoshiaki 
Published: July 2007

AbstractThis paper presents a schematic language for describing the functional specification of hardware. The language provides a new computer input medium using a top‐down design essential to the systematic design of large‐scale hardware. This language has a special description model that uses a signal based on a new concept of connections between function blocks, called a virtual interface signal. This signal allows a designer to refer to it unrestrictedly among a hierarchy of function blocks. Therefore, the design can describe both an outline of the connections at an early design stage and the detailed connections at the final design stage based on the same description rules. Moreover, the designer can specify the hardware function by means of both a function block and a state transition diagram.Some preliminary experiments show that the language herein requires only about a quarter of the description man‐hours as that of a conventional character‐based description language. Also, using two types of design diagrams reduces the description man‐hours by about 40 percent over the function block diagram only.
Design of multiple‐valued module array using signed‐digit arithmetic
Authors: Kameyana Michitaka , Higuchi Tatsuo , Nomura Masahiro 
Published: July 2007

AbstractA new design methodology for arithmetic VLSI systems is proposed using a radix‐4 minimum‐redundant signed‐digit (SD) arithmetic module. The module is composed of an adder, a sign inverter and a partial product generator. Any arithmetic systems based on addition, subtraction and multiplication can be realized by appropriately specifying interconnections between the modules. This module array is very useful for short design turnaround time. Moreover, the operating speed of the proposed module array systems is comparable to that of the fastest binary systems.
Identifiability of hidden markov processes and their minimum degrees of freedom
Authors: Ito Hisashi , Amari Shun‐Ichi , Kobayashi Kingo 
Published: July 2007

AbstractThere exists a class of stochastic processes based on a finite‐state discrete‐time Markov chain, where the states are not directly observable and only the output symbols generated by the states are observable. If different states produce the same output symbol, the process is called a hidden Markov process. It is very important both in theory and applications. It is known that two Markov processes with different transition matrices are equivalent hidden Markov processes. The problem has been considered interesting concerning by what structures such a situation can arise.This paper gives a complete solution to the identification problem of the hidden Markov process, which has long been proposed and is still unsolved. At the same time, a structure of this kind of process, which has been unknown, is revealed. An n algebraic technique is used in the discussion, where new concepts called Δ‐subspace and Δ‐cy‐clic subspace are introduced into the framework of subspace and cyclic subspace in the usual linear algebra.In this paper, a Δ‐subspace is actually constructed which gives the effective minimum degree of the hidden Markov process. It is shown also that two stochastic processes are equivalent if and only if there exists an isomorphism between the Δ‐sub‐spaces.
SPRODICE: A diagnosis support program for the interpretation of brain CT images
Authors: Yan Zhuang‐Zhi , Eiho Shigeru , Tanaka Hiroshi 
Published: July 2007

AbstractThis paper describes the knowledge base system SPRODICE, which is constructed to support the interpretation and diagnosis of brain CT images. The knowledge base of the proposed system has the knowledge about the internal structure of the brain, and diseases are represented by a hierarchical semantic network, and the sites of common incidence for each disease as well as the finding patterns based on the intuition and experience of the doctor are described by the rules.The system positively introduces the doctor's decision in the course of the diagnosis so that the diagnosis is not left to the system, but proceeds by the cooperation of the doctor and the system. This approach originated from the idea that the final responsibility of the result of diagnosis lies with the doctor.It is made possible also to complement the incompleteness and insufficiency of the knowledge, which is always a problem in the diagnosis‐support system, by the common sense and the experience of the doctor. The system is implemented on a personal computer using Prolog, and can support approximately 80 kinds of interpretation and diagnosis of brain diseases. As a result of experimental diagnosis of 107 pathological cases, it is seen that the accuracy of diagnosis by SPRODICE is 82.2 percent when used by a non‐specialist, and 83.4 percent when used by a specialist.
Designing method for ARMA four‐line lattice filter with sliding rectangular window
Authors: Haseyama Miki , Nagai Nobuo , Miki Nobuhiro 
Published: July 2007

AbstractThis paper derives a design method for an ARMA 4‐line lattice filter using a sliding rectangular window. The adaptive ARMA 4‐line lattice filter already proposed uses a forgetting factor, which is one of the weighting functions to estimate coefficients of a time‐varying system in which system coefficients vary with sufficient smoothness. Therefore, the effect of past observed signal over the estimated coefficients decreases exponentially.The filter presented here is realized using a rectangular window because the concern is over the effects of past observation signal rather than window length. Using this filter, an input signal is estimated when designing; furthermore, a system can be identified in which an arbitrary section in the frequency domain is weighted.Thus, by not only analyzing voice signal which is considered a model whose input signal is unknown and EEG data but also by weighting the frequency domain, for example, the holmant in the low‐frequency domain can be estimated in low degree with very high precision and a specific wave (such as a α activities) in EEG data can also be detected. Moreover, in this paper the algorithm is verified by model experiments.
Parametric loudspeaker—characteristics of acoustic field and suitable modulation of carrier ultrasound
Authors: Aoki Kenichi , Kamakura Tomoo , Kumamoto Yoshiro 
Published: July 2007

AbstractDue to the inherent nonlinearity of the medium, finite amplitude ultrasound interacts with itself and generates some secondary waves in the sound beam. The parametric loudspeaker, making use of this phenomenon, has a sharp directivity and might be applied to a speech transmission system under the limited environment.In this paper, a numerical analysis method available for high sound pressure levels, where the nonlinear interactions of ultrasound become greatly active, can be used successfully to theoretically design the parametric loudspeaker. It is reported that the numerical computations agree well with the experiments by a circular aperture projector of radius 21 cm and carrier frequency 27 kHz.To develop the parametric loudspeaker for practical uses, the problems on harmonic distortions and the physiological effect on human being must be solved. Based on the theoretical prediction, the reasonable solutions for such problems are considered in accordance with appropriate primary wave modulations.
Adapative formant estimation with compensation for gross spectral shape
Authors: Toyoshima Takuji , Miki Nobuhiro , Nagai Nobuo 
Published: July 2007

AbstractFormant estimation from a speech signal that is observed acoustically is importand for speech analysis and synthesis. This paper proposes an adaptive formant estimation method with compensation for the gross spectral shape. This estimator can estimate the center frequencies and the bandwidths of formants (anti‐formants) based directly on the pole‐zero transfer function represented by the products of the secondand first‐order factors. Since the proposed method can compensate the gross spectral shape adaptively, excellent formant estimation is expected for continuous speech whose gross spectral shape is time‐varying. Therefore, the method proposed herein is applied to the synthetic signal and real speech, and the validity of this method is demonstrated. Furthermore, the Single‐Stage Iteration Filter is the estimation algorithm introduced for use in the proposed method. It is shown that the estimation results of tracking with little degradation are obtained stably in the transient part of the spectra.
Nondeterminism and existence of finite‐state supervisors in discrete‐event systems
Authors: Ushio Toshimitsu 
Published: July 2007

AbstractSupervisory control initiated by Ramadge and Wonham is a very useful control technique for discrete‐event systems. A supervisor realized by a finite automaton is called a finite state supervisor. It is clear that a finite state supervisor exists for every regular controllable language. It is very important to show a necessary and sufficient condition for the existence of a finite state supervisor. Moreover, there are few studies for the effect of nondeterminism in a supervisor on control.First, this paper shows that there exists a deterministic finite state supervisor for every control specification for which a nondeterministic finite state supervisor exists. Then a necessary and sufficient condition for the existence of a finite state supervisor is proved. As a result, it is shown that no finite state supervisor exists if a controlled discrete‐event system is modeled by a finite automaton and control specification is given by a nonregular language. Finally, a simple manufacturing system and a nonregular control specification (for which a finite state supervisor exists) are demonstrated.
Hierarchical detailed floorplanning with global routing in VLSI layout design
Authors: Ohmura Michiroh , Wakabayashi Shin'Ichi , Miyao Jun'Ichi , Yoshida Noriyoshi 
Published: July 2007

AbstractIn a VLSI layout design using the building block approach, the design is divided into two phases, placement and routing. On the other hand, a new hierarchical floorplanning method was proposed by Dai et al., in which a global routing for the evaluation of the placement is determined simultaneously during the design of relative placement. However, the precise estimation of routability is difficult since the global routes in this method do not correspond to the routing region such as channels and switchboxes. In this paper, a new method is proposed, which simultaneously and hierarchically obtains floorplan, shapes and positions of modules, and global routes which directly correspond to switchboxes and channels. In this method, the routing‐based partitioning, the hierarchical detailed global routing, and the hierarchical positioning are repeatedly executed, and a chip with small area and short wire length is obtained. This paper presents these three algorithms, and discusses the experimental results of each algorithm and the whole proposed method in a comparison to the conventional method that separately executes placement and routing.