bluuebunny/crossref_metadata_2025 huggingface dataset:
Perception of depth movement and temporal frequency characteristics of stereoscopic vision
Authors: Yano Sumio , Mitsuhashi Tetsuo
Published: July 2007

The repetition frequency and the maximum disparity in stereoscopic vision where depth movement is perceived are determined using a static random dot stereogram (SRDS). Furthermore, the temporal frequency characteristics of the maximum fusible disparity are determined using a dynamic random dot stereogram (DRDS). The results show that in both cases, as the frequency of depth movement increases, the maximum fusible disparity decreases. For sine waves above 15 Hz and square waves above 7.5 Hz, binocular fusion is not possible when the target is the SRDS. For both sine and square waves above 7.5 Hz, binocular fusion is not possible when the target is the DRDS. In both cases, binocular fusion is only possible at lower frequencies. It is clear that compared to SRDS, the maximum fusible disparity is larger for DRDS when the center of motion is set on the plane of the screen and becomes smaller when the center of depth motion is shifted off the screen as the shift of the center of motion increases or fusion becomes impossible in the high frequency range.
A fast learning algorithm for neural networks and its applications to adaptive equalizers
Authors: Miyajima Teruyuki , Hasegawa Takaaki , Haneishi Misao
Published: July 2007

This paper proposes a fast learning algorithm of neural networks and evaluates the performances of adaptive equalizers using neural networks trained by the proposed algorithm in a frequency‐selective fading channel. The backpropagation (BP) algorithm which is used widely to train neural networks has a slow convergence rate because it is based on the gradient descent method.

This paper presents a fast learning algorithm using the recursive least squares (RLS) algorithm which has a fast convergence rate as an adaptive algorithm for adaptive linear filters. In the proposed algorithm, the sum of the squared error between the actual total input and the desired total input is used as the cost function to apply the RLS algorithm. A simulation result on the exclusive‐OR problem indicates that the proposed algorithm is about 8.8 times faster than the BP for the number of iterations required to converge.

Recently, there has been interest in adaptive equalizers as an application field of neural networks. However, the performance of an adaptive equalizer using a neural network in a frequency‐selective fading channel which is observed in land mobile communications has never been evaluated. Therefore, in this paper, the performances of adaptive equalizers using neural networks trained by the proposed algorithm in a frequency‐selective fading channel are evaluated. Especially, an adaptive equalizer using the selectively unsupervised learning neural network proposed by the authors is considered. The adaptive equalizer can reject the false learning by carrying out learning selectively. It is shown that the adaptive equalizer is superior to the conventional one and the one using the conventional neural network.
Measurement and estimation of system nonlinearity via a neural network
Authors: Yana Kazuo , Yoshida Hisashi , Komai Masanori
Published: July 2007

This paper defines the degree of nonlinearity as a measure for the nonlinearity of the system. A method for estimating the nonlinearity is proposed based on the input and the output time‐series signals under the actual condition that the additive observation noise is included. The degree of nonlinearity of the system takes a value between 0 and 1. It approaches 1 when the part of the variational power that cannot be represented by the linear combination of the input increases in the output variation depending on 0‐input in the linear system.

A multilayer perception is introduced as a parametric function which represents the wide class of nonlinear functions needed in the estimation. An example is shown of the family of memoryless and nonlinear systems where the degree of nonlinearity changes from 0 to 1 by the change of the system parameter. An example also is shown of the system with a finite memory having a degree of nonlinearity of 1.

By a computer simulation, the validity of the nonlinearity estimation proposed in this paper is demonstrated. The method will be applied effectively to the modeling of the system based on the observed input and output signals.
Pupil size and eeg affected by visual stimuli
Authors: Nagatsuka Mamoru , Shimizu Yasutaka
Published: July 2007

The purpose of this paper is to study the objective evaluation of educational video software, etc., by biological data. A visual stimulus is presented using CRT, the pupil size and EEG are examined simultaneously, and the changes are analyzed. In such a simultaneous measurement, the interference of CRT noise to EEG measurement must be avoided. A special shielding room is designed using a transparent shielding glass so that the stimulus can be presented to a subject from the outside. The effectiveness of the shielding is verified. The effect of attaching the pupil‐size measuring instrument exerted on EEG measurement is examined. A still‐picture pattern with semantics is presented to the subject while adjusting the average brightness to a constant value, and the pupil size and EEG are measured simultaneously. A negative correlation is observed between the EEG power in the 9.0‐ to 11.0‐Hz band and the pupil size. It is seen also that, when a pattern that strongly interests the subject is presented, the pupil size becomes large and the band power becomes low. Thus, it is demonstrated that the difference of the content of the presented pattern can be evaluated more clearly by the simultaneous measurement.
Probability distribution with respect to expansion or contraction of image size
Authors: Iijima Taizo
Published: July 2007

Often, in handwriting a character, a natural expansion or contraction occurs even if the writer intends to write the character in a specified size.

This paper considers the expansion‐contraction phenomenon which appears statistically in drawing a figure in general. A theoretical investigation is presented from the theory of probability, and the shape of the probability distribution governing the phenomenon is analyzed mathematically. The approach also gives an answer from the viewpoint of the theory of probability to the problem where the length is expanded or contracted unintentionally, even if a constant length is intended.

This paper shows a typical mathematical approach in which the determination of the shape of the probability density function is reduced to the solution of the special functional equation. It is considered to be interesting also from the viewpoint of the theory.
Bifurcation of heteroclinic orbits in a circuit containing a josephson junction element
Authors: Ueta Tetsushi , Kawakami Hiroshi
Published: July 2007

The circuit equation of the circuit containing a Josephson junction and the equation of motion of a pendulum in which an elastic restoring force is applied in the direction of rotation are described in terms of a second‐order ordinary differential equation containing the sum of a trigonometric term on the state and a linear term. In such a dynamic system, the number of saddles and sinks changes according to the parameter values and no periodicity exists with respect to the location of the saddles and sinks, thus analysis is difficult.

In this paper, a circuit containing a Josephson junction is chosen as an example of such a dynamic system. Classification by the tangent bifurcation of the saddles and sinks and the results of the analysis based on the heteroclinic orbits on the phase plane are presented. The heteroclinic orbit presents a global bifurcation on the phase plane due to its structural instability. The parameters generated by this orbit are used as the values for the bifurcation, and the bifurcation set was derived on the parameter plane. As a result, the unique linking number is defined for a particular parameter region surrounded by the bifurcation curve. This value can be used as a guideline for rotation of the orbit on the phase plane. Further, by combining it with the bifurcation ensemble, a classification of the stable sinks in the basin is made possible.
Selection of fuzzy if‐then rules by a genetic method
Authors: Ishibuchi Hisao , Nozaki Ken , Yamamoto Naohisa , Tanaka Hideo
Published: July 2007

This paper proposes a genetic algorithm‐based method for constructing a fuzzy classification system with fuzzy if‐then rules. In the proposed method, a rule selection problem for constructing a compact fuzzy system with high classification power is formulated as a combinatorial optimization problem with two objectives: to maximize the classification rate and to minimize the number of rules. Then a method of implementing genetic algorithms is proposed for the application to this problem and its effectiveness is demonstrated by computer simulations. The implementation of genetic algorithms in this paper employs an approach where a set of fuzzy if‐then rules is coded as a single individual.
Fundamental theory of natural observation transformation
Authors: Iijima Taizo
Published: July 2007

With regard to the theory of natural observation proposed as a new method of waveform analysis and although papers by the author have already been published over the last few years, this paper attempts a generalization based on the theory. As a result, the theory of natural observation can largely be divided into the neighboring type and the equilibrium type. Further, it was clarified that the previous theories belong to the neighboring type.

In the treatment of acoustic vibration waveforms such as voice, the hitherto not discussed equilibrium type is desirable. Also, based on the forementioned theories, the general form of natural observation transformation is proposed anew as a substitute for Fourier transformation and, in particular, the standard form thought to be useful hereafter is shown concretely.
Origin of the natural observation theory of standard form
Authors: Iijima Taizo
Published: July 2007

The theory of natural observation has been proposed as a new method of analysis to replace the Fourier analysis method. It was systematized as a theory with two major types—the neighboring type and the equilibrium type. Especially, although the nucleus of the theory is of standard form, the description with regard to the starting point of the theory in the past has not always been plain and comprehensible.

This paper is a radical improvement in this regard and was written to clarify the origin of the theoretical development. Although the previously published theories are not completely revised, this paper is considered significant from the viewpoint of clarification of the base of the theoretical development.
Spatio‐temporal analysis of eye movement patterns based on the maximum entropy method and the higher moment features
Authors: Sakaino Hidetomo , Tetsutani Nobuji , Kishino Fumio
Published: July 2007

This paper considers the eye movement pattern when observing the eye mark pattern. The spatio‐temporal method of spectrum analysis based on the maximum entropy is proposed as well as the statistical method of analysis combining the higher‐order moment features to extract the features from the analyzed spectrum pattern. The similarity pattern is used as the eye mark pattern, where segment, polygon, and circle are used as the primitive patterns. The eye mark pattern is projected on a large screen with the view angle of 80 deg. The density of the pattern is approximately 1.04 and 0.35 deg in terms of the view angle. The spectrum pattern of the movement is analyzed from the two standpoints of time and frequency. It is seen as a result that the number of angles, shape, and pattern density are reflected more strongly on the durations of the gaze and saccade movement rather than their frequencies in the observation period. This result suggests that the image features will be estimated from the movement pattern.
Montgomery modular‐multiplication method and systolic arrays suitable for modular exponentiation
Authors: Iwamura Keiichi , Matsumoto Tsutomu , Imai Hideki
Published: July 2007

The Montgomery method is known as a method to execute modular multiplications without using divisions, and several systolic arrays have been proposed for execution of the Montgomery method. A problem in the Montgomery method is that the number of output bits may exceed the number of input bits. In the past implementations, the size of the output must be examined and corrected each time the method is executed, which is an obstacle in improving the efficiency.

From such a viewpoint, this paper derives the general condition so that the size of the output need not be examined each time the Montgomery method is executed and proposes two types of systolic arrays that execute the Montgomery method under that condition. These arrays are more efficient than the systolic array proposed previously by the authors for modular multiplications. The method is effective and practical for VLSI implementation such as on a chip.
Gesture description and structure of a dictionary for intelligent communication of sign language images
Authors: Xu Jun , Tanahashi Shin , Sakamoto Yuji , Aoki Yoshinao
Published: July 2007

In the intelligent transmission of the sign language image based on the semantic information, one possible method is to transform the semantic information on the receiving side into the motion parameters of the upper extremities and to synthesize the animation image of the sign language. For this purpose, the word dictionary to describe the motion of the upper limb corresponding to the semantic information must be constructed. A problem then is that the human upper limb has a large degree of freedom. It is difficult to control skillfully the posture of the upper limb using the motion parameters for the joint movements. Thus, the complex motion is realized by combining the posture and motion of the upper limb, corresponding to the sign language.

This paper proposes a method in which the shape of the hand to be used in the sign language is described by a table and the motion of the upper limb is described and represented by the motion features of the gesture based on the joint angle model. The method to construct two kinds of word dictionaries, called “representative dictionary” and “realizing dictionary,” are proposed to generate the animation image for the sign language based on the semantic information. The representative dictionary gives the basic motion of the sign language. The realizing dictionary describes the control parameters such as the iteration and the speed of motion. The word in sign language is realized by adding the realizing form to the representative form. In the proposed method, the description of the word in the signal language is simplified, which makes it easy to control the upper limb posture as well as to iterate or emphasize the motion, using the method proposed in this paper, a word dictionary is constructed to describe the gesture of the sign language. A system is discussed in detail which transforms the input sentence in Japanese into the animation image.
Synthesis of decentralized state feedbacks for large‐scale discrete event systems
Authors: Takai Shigemasa , Kodama Shinzo , Ushio Toshimitsu
Published: July 2007

This paper considers the large‐scale discrete event system which is composed of multiple concurrently operating subsystems. The decentralized state feedback control is discussed for the case where the control specifications are given by predicates concerning the whole system. First, a necessary and sufficient condition is shown for a predicate which is obtained by a global state feedback to be obtained also by a decentralized state feedback. However, it should be noted that, in general, there exists more than one decentralized state feedback that can achieve the global predicate.

From such a viewpoint, the maximally and minimally permissive decentralized feedbacks are defined and investigated. It is shown that there always exists the minimally permissive decentralized feedback, and its construction method is presented. Also, it is shown that, although the maximally permissive decentralized feedback does not, in general, exist, it can be obtained in the case that local state feedbacks are constructed according to a specified order. The construction method for that case is shown.
Double‐talk detection for adaptive noise canceller
Authors: Mizuno Kimiyasu , Kubota Hajime
Published: July 2007

It is known that the estimation accuracy deteriorates in the double‐talk period in the traditional adaptive noise canceller. The deterioration can be ameliorated by the conventional method if the double‐talk period can be detected. However, the detection of the double‐talk period has not been presented (a method is proposed for the adaptive echo canceller, which, however, has a problem in the direct application to the adaptive noise canceller).

From such a viewpoint, this paper proposes a double‐talk detection method for the adaptive‐noise canceller. The method is based on the correlation of the exponential weighted square sum and has the following features. No parameter needs to be known beforehand. The result is less affected by the path variation. The distortion to the desired signal can be suppressed. The computational complexity can be reduced by decimation. The method can also be applied to the adaptive echo canceller.

In this paper, the validity of the method is demonstrated by a theoretical analysis. The following result is obtained by a computer simulation. When the adaptive noise canceller is controlled by the proposed method, the accuracy of the estimation is improved by approximately 30 dB and the distortion to the desired signal is suppressed by approximately 15 dB, compared to the case where the method for the adaptive echo canceller is used.
Embedded RAM test using flag‐scan register
Authors: Maeno Hideshi , Iwade Shuuhei , Kayano Shimpei , Sakao Masayoshi
Published: July 2007

New test methods and a test circuit for the testing of embedded RAMs on ASICs are proposed. These test methods are based on the scan path method, and a new scan register, called Flag‐Scan Register, which is dedicated to RAM test, has been developed for the test methods. Also, high‐speed testing is possible by using exhaustive pseudorandom addressing. Furthermore, the methods have been applied to gate array‐based RAMs and the effectiveness has been verified.
Improvement of convergence speed in adaptive filter by multirate processing
Authors: Kashimoto Tsuyoshi , Takahashi Shin‐Ichi
Published: July 2007

Exact estimation of frequencies of sinusoidal signals corrupted by noise is an important problem in a variety of areas, and various kinds of methods for the solution of this problem have been proposed. Among these methods, the adaptive spectral estimation method, which processes data recursively, needs consideration of the convergence property of the adaptive filter as well as the precision of the spectral estimation. In this paper, we propose a method which improves the technique of analytic signal processing used to improve estimation precision slowing the convergence speed of the adaptive filters. This method makes good use of the data discarded by decimation and processes two series of the same statistics in parallel. By this operation, the number of times the coefficients are updated in the adaptive filter is doubled and, therefore, the rate of convergence is much improved. Furthermore, by increasing the number of data by interpolation of the observed data, faster convergence speed than that of the conventional method is realized. This method has an advantage of simple structure. It can be also easily applied to other adaptive filtering using subband filters.
A subclass of petri nets where liveness is preserved under the earliest firing rule
Authors: Ohta Atsushi , Hisamura Tomiji
Published: July 2007

The Petri net is a powerful tool for modeling, analysis, verification, and evaluation of discrete event systems, and liveness is one of the most important analytical properties of the Petri net. On the other hand, introduction of the earliest firing rule gives an extended class of the net that is useful from both theoretical and applicative viewpoints.

This paper clarifies a relation between ‘normal’ liveness of Petri nets and liveness of the net under ‘the earliest firing rule.’ POC nets, a subclass of Petri nets where normal liveness is a sufficient condition for liveness under the earliest firing rule are proposed. Then conditions for necessity are investigated, considering the two rules for multiple firing of a single transition, i.e., single servers and infinite servers. This provides a subclass where the two forementioned livenesses are equivalent to each other. Finally, computational complexity for liveness problem is considered.
The “understanding potential scores,” a new estimation score based on the s‐p chart: Definition and experimental discussion
Authors: Miwa Kazuhisa , Shimomura Tsutomu
Published: July 2007

A new estimation score, the Understanding Potential Score, based on the S‐P chart that is widely used as an educational estimation method is defined. The value of the Understanding Potential Score of the response increases with the ease of the problem and the ability of the student. Empirical discussions on the results of applied tests indicate that the degree of each subject's understanding of each problem can be measured quantitatively. The relation between the Understanding Potential Score and the ratios of correct to incorrect responses and of confident to unconfident responses are discussed. The relation between the Understanding Potential Score and the transition patterns of responses from post‐instruction tests to retention tests is also examined.

These discussions permit greater understanding of the mechanisms of subjects' objective and subjective estimations. The Understanding Potential Score is also applied to the Unified Evaluation Method (a well known estimation method); with the result, a better estimation method is created by combining the S‐P chart analysis and the Unified Evaluation Method.
Spoken language identification by ergodic HMMS and its state sequences
Authors: Nakagawa Seiichi , Seino Takashi , Ueda Yoshio
Published: July 2007

This paper describes an automatic text‐ and speaker‐independent language identification method based on hidden Markov models (HMMs) for acoustic features. The hidden Markov modeling is used to represent the phonotactics for each language. Each language has its proper phonotactics.

The HMM topology here is a fully structured (ergodic) model wherein any state could transit to all states. Two kinds of HMMs are used: the discrete HMM (DHMM) with the codebook and the continuous density HMM (CHMM). The HMM was trained using both the Baum‐Welch (forward‐backward) algorithm and the Viterbi algorithm. The latter was used for emphasizing the state transition probability.

For comparison, experiments also were conducted on the identification using a mixtured Gaussian distribution model with one state. This single‐state Gaussian distribution model gave the same performance as the HMM trained with the Baum‐Welch algorithm. This is because the transition between states which reflects the characteristics of each language does not affect the likelihood scores very much. This problem was addressed by emphasizing the transition probabilities and using the Viterbi algorithm, which resulted in an improvement in the recognition rates. The trigram for optimal state sequence is introduced. Combining it with the HMM produced the best results.
Analysis of current densities induced inside human model exposed to AC electric field
Authors: Chiba Atsuo , Isaka Katsuo , Onogi Yukio
Published: July 2007

The current induced inside the human body by the mutual interaction between the human body and the ac electric field has been analyzed by the surface charge method and the finite element method. However, in these methods, it is not possible to analyze the current induced inside the human model of a three‐dimensional shape consisting of biological tissues with different conductivities. The authors propose a method for analysis of the current density in the human body of a three‐dimensional shape by taking into account the conductivity of the biological issues via the scalar potential method of the integral equation. The results of the analysis of the induced current density in the model by the present method have been verified from the experimental results of the metallic human model.
Performance analysis method for system bus architectures in multimedia communication terminals
Authors: Sakamoto Hideki , Ishibashi Yutaka
Published: July 2007

This paper proposes a new method for analyzing the performance of system bus architectures, e.g., first‐come/first‐served (FCFS) bus, priority bus transfer control, separate bus, and multiple bus, in a multimedia communication terminal. Performance is analyzed using a queueing network model (QNM). The QNM of each system bus architecture is converted into an equivalent QNM by using virtual server expressions and then analyzed by a queueing network analyzer (QNA). Numerical results show that this method is sufficiently accurate by comparison with simulation results and that the effectiveness of a system bus architecture depends on the relationship between processing speed and bus speed.
Measurement and analysis of charge distributions induced on rectangular AT‐cut quartz resonators
Authors: Watanabe Yasuaki , Sekimoto Hitoshi , Kitada Yoshinori , Oomura Yoshimasa
Published: July 2007

For the design of a strip‐shaped rectangular AT‐cut plate used frequently in recent years, an accurate spurious analysis method is required to avoid many spurious vibrations which have phase variations in both theXandZ' directions. At present, Mindlin's approximate analysis method based on the plate equations has the highest accuracy, although its degree of approximation has not been studied sufficiently.

In this paper, the spurious modes excited in a rectangular AT cut are studied. In addition, to investigate the applicability of the plate equation for the analysis of characteristics of these modes, the surface charge distributions of the spurious mode are obtained experimentally and compared with the computations. From the computed results and the experimental results obtained with a highly accurate surface charge measurement system based on the principle of the electric probe, it is found that the spurious modes all belong to the thickness‐flexure and the face‐shear/flexure except for the weak resonances considered to be excited by the nonsymmetry of the plate. It is pointed out that improvement of the degree of approximation of the plate equations requires adjustment of the coupling between the thickness‐flexure modes and the face‐shear/flexure modes.
ATM‐oriented multimedia LAN architecture
Authors: Suzuki Hiroshi , Iwata Atsushi , Ikeda Chinatsu , Mori Naoki
Published: July 2007

The shared media local area networks (LAN) such as Ethernet/FDDI has the bottleneck of bandwidth scalability. ATMLAN based on asynchronous transfer mode (ATM) switch is considered interesting at present as the next‐generation multimedia LAN to dissolve this bottleneck. The research and development of ATM has mostly been promoted for application to the public network. With respect to LAN, a new investigation is needed which includes the architecture since there are various requirements such as compatibility to the existing protocol, the simplification of the network control, and the drastic reduction of the system cost.

This paper proposes the ATM‐oriented multimedia LAN (ATOMLAN) architecture which meets the fore‐mentioned requirements. The proposed architecture has the following three features: (1) the ATMLAN addressing, considering the affinity to the existing protocol and the efficient internetworking; (2) the high‐speed connection control to realize a high throughput for the connectionless‐type data transfer; and (3) the simple and efficient traffic control for the high‐speed burst‐multimedia service. Using the proposed architecture, a seamless high‐speed multimedia network can be realized, from the desk‐top to the broadrand network.
Analysis of acoustic characteristics in the vocal tract with inhomogeneous wall impedance using a three‐dimensional fem model
Authors: Matsuzaki Hiroki , Hirohku Tohru , Miki Nobuhiro , Nagai Nobuo
Published: July 2007

The vocal tract can hardly be considered as having a uniform wall impedance. The palate, for example, is hard and the tongue is soft. The wall impedance is obviously nonuniform. However, so far, there is no detailed knowledge about the acoustic characteristics in the vocal tract when the impedance distribution is nonuniform along the vocal tract with a three‐dimensional structure. It may be possible that this nonuniform distribution is one of the factors for naturalness or individuality in the speech production process. From such a viewpoint, it is necessary to investigate this point.

This paper considers the sound tube with a circular or elliptic cross section as a simplified model for the vocal tract. The acoustic characteristics within the tube, when the distribution of the wall impedance is varied, are analyzed in three dimensions using FEM; and the result is reported. The following properties are shown as a result.

When the wall becomes softer or when the cross section is deformed from circular to elliptic, the formant bandwidth increases. At the same time, the sound pressure distribution as well as the particle velocity distribution decrease their amplitude. Another aspect is that the sound wave deviates from the planar wave due to the wall impedance and the shape of the wavefront is affected by the impedance distribution.
A practical algorithm for DC operating‐point analysis of large‐scale circuits
Authors: Inoue Yasuaki
Published: July 2007

SPICE‐type general‐purpose circuit simulators are used widely as a support tool for circuit design. It often happens, however, that the do operating‐point analysis does not converge. To cope with such a situation, various approaches have been proposed based on continuation methods with the global convergence property, but these have yet to come to the stage of practical application to large‐scale circuits.

This paper proposes a practical algorithm which can be implemented on the general‐purpose circuit simulators with modified nodal formulation, for determining the de operating‐point of large‐scale circuits. As the first step, the concept of “modified cut‐set analysis” is introduced and some properties of the modified nodal equation are presented. Then it is shown, in practical circuits, that the convergence of the algorithm is theoretically guaranteed. The proposed algorithm is then implemented on an existing general‐purpose circuit simulator and applied to a bipolar analog LSI to demonstrate its effectiveness. For the LSI circuit formulated in 18, 553 modified nodal equations, the de operating point was determined in 270 minutes using an IBM RS6000‐550.
An identification method for nonminimum‐phase ARMA system using phase information derived from third‐order statistics
Authors: Miyazaki Nozomi , Hamada Nozomu
Published: July 2007

One of the most important problems in signal processing is to investigate the dynamics of the signal through the statistical analysis of the random signal and to identify the model that describes the generation process for the signal. Until now, the second‐order statistics, such as autocorrelation, has been used for this purpose. A problem then is that the second‐order statistics do not contain the phase information of the signal, and it is impossible to analyze the nonminimum‐phase signal.

From such a viewpoint, recently, considerable attention has been given to analysis of the signal using the higher‐order statistics which contain also the phase information of the signal. In this paper, the observed signal is modeled as an output of the linear time‐invariant system with the non‐Gaussian white process as the input. A method is proposed which identifies the signal generating system parametrically using the third‐order cumulant of the observed signal. The outline of the method is as follows.

The all‐zero system with the same phase response as the system to be estimated is determined from the cepstrum of the third‐order cumulant of the observed signal. Then, by applying the phase‐invariant transform to the all‐zero system, the poles and zeros of the system are rearranged to match the amplitude response of the system. Since the third‐order cumulant is insensitive to the Gaussian additive noise, another feature of the method is that it is effective even if a Gaussian additive noise is added to the observed signal.
Singular point analysis for dynamical systems with many parameters‐an application to an asymmetrically and densely connected neural network model
Authors: Tanaka Hisa‐Aki , Okada Atsushi , Horiuchi Kazuo , Oishi Shin'Ichi
Published: July 2007

In the nonlinear dynamical system, the singular point analysis (Painleve test) is known to be an analytic method for identifying integrable systems or characterizing chaos. In this paper, nonlinear dynamical networks, which are simplified models for mutually connected analog neurons, are studied mainly in terms of the singular point analysis by introducing the complex time. The following results were obtained: 1) some conditions for integrability and first integrals are identified; 2) as an application of Yoshida's theorem, it is proven that many cases in our system are (algebraically) noninegrable; 3) a self‐validated numerical algorithm is proposed to overcome some difficulties known to appear in applying the singular point analysis (Yoshida's theorem) to higher‐order systems.
SAR image reconstruction using a Kalman filter
Authors: Shirakawa Tomoaki , Kitajima Hideo , Ogawa Yoshihiko , Shimono Tetsuo
Published: July 2007

This paper proposes a new image reconstructing algorithm for a synthetic aperture radar (SAR). For fast computation, the proposed method uses a Kalman filter in the time domain while many conventional methods use frequency domain procedures. This method is applicable to real‐time imagery because images are recursively reconstructed. Through a reconstruction simulation by pseudo data, it is shown that a superior reconstructed image is obtained by the proposed method as compared to the conventional method.
A very large vocabulary continuous speech recognition algorithm for telephone directory assistance
Authors: Minami Yasuhiro , Yamada Tomokazu , Shikano Kiyohiro , Matsuoka Tatsuo
Published: July 2007

This paper proposes a speech recognition algorithm for large vocabulary continuous speech. The proposed algorithm is based on the hidden Markov model (HMM)‐LR algorithm using a generalized predictive LR parser and phoneme HMMs. The following three techniques are applied to improve recognition performance and reduce processing time.

The forward and the backward likelihood are used to accurately determine the likelihood in the beam search.

To reduce the trellis computation in HMM speech recognition and for efficient search, only the speech frames in which the predicted phoneme seems to exist are used by the window for phoneme matching.

For efficient search, adjusting identical phoneme sequences are merged by checking the stack and the state of the LR parser.

The algorithm was applied to a telephone directory assistance task involving more than 70, 000 subscribers. A recognition experiment for continuous word utterance was done. The sentence recognition rate was 85 percent for speaker‐dependent speech recognition; the sentence recognition rate was 71 percent for speaker‐independent speech recognition. The sentence understanding rate was 59 percent for speaker‐dependent speech recognition with spontaneous utterances.
Phoneme HMM evaluation algorithm without phoneme labeling applied to continuous speech hmm evaluation
Authors: Minami Yasuhiro , Matsuoka Tatsuo , Shikano Kiyohiro
Published: July 2007

Phoneme Hidden Markov Model (HMM) are generally evaluated in terms of the phoneme recognition rate by using speech data extracted based on phoneme labels. This paper proposes an evaluation method that does not use phoneme labels for extraction. Consequently, phoneme HMMs can be evaluated even if a speech database without phoneme labeling is used.

In this study, concatenation training of the phoneme HMMs is executed using a large‐scale speaker‐independent continuous‐speech database. Evaluation of the HMM phoneme recognition rate which is a function of the number of training speakers, using the proposed evaluation method demonstrates its effectiveness.
A new HVHD model four‐layer channel router using a channel‐graph
Authors: Rhee Byungho , Sugai Yasuo , Hirata Hironori
Published: July 2007

This paper proposes a new HVHD four‐channel routing technique using the channel‐graph. The diagonal routing model, which differs from the conventional four‐layer channel routing, is introduced in the proposed method; and the nets for the diagonal routing are selected by the algorithm based on the weighted channel‐graph. The rest net, left after the diagonal routing, is routed in HVH three‐layers.

The proposed method is applied experimentally to several benchmark data, including Deutsch's difficult example. It is shown that tracks are reduced by approximately 20 percent compared to the conventional four‐channel routing method, and the result by the proposed method is closer to the result of the conventional five‐layer routing. Thus, the effectiveness of the proposed method based on the channel‐graph is demonstrated.
Determining element‐value for linear resistive star circuits containing two noncontact nodes
Authors: Suzuki Yoshihiko , Matsuura Hideaki
Published: July 2007

This paper considers the method that measures the network‐element values for the linear resistive network containing the inaccessible nodes and a network topology that is known and element values that are unknown. Measured data at the accessible nodes are used. Whether all of the element values can be determined from the measured data is dependent on network topology. A discussion of what type of configuration for which element values can be determined is presented. A perfect solution is not obtained when the inaccessible nodes number more than two. A new method of determining the element values is given for the circuits containing two inaccessible nodes.
Comparison of text‐independent speaker recognition methods using vector‐quantization distortion and discrete and continuous HMMs
Authors: Matsui Tomoko , Furui Sadaoki
Published: July 2007

The results of speaker recognition methods using vector quantization (VQ) distortion and discrete or continuous ergodic hidden Markov models (HMMs) are compared. The effectiveness of these methods is examined from the viewpoint of robustness against utterance variation such as differences in content, temporal variation, and changes in utterance speed. It is shown that the continuous HMM performs much better than the discrete HMM and its performance is close to that of the VQ distortion method. When the amount of training data is limited, however, the VQ distortion method achieves a better recognition rate than the continuous HMM. The transition information between the states is shown to contribute little to identifying the individual characteristics of a voice. An increase in the number of states or in the number of mixture components in a state both have an equal effect, and recognition performance is almost completely determined by the product of these two numbers.
Parallel‐form realization of 2‐D adaptive separable‐denominator state‐space filters
Authors: Muneyasu Mitsuji , Hinamoto Takao
Published: July 2007

This paper treats the parallel‐form realization of two‐dimensional (2‐D) adaptive state‐space filters whose transfer functions are separable in the denominator. the adaptive filters are described by the Roesser local statespace (LSS) model, and the least mean squares (LMS) method is used here to adjust the filter parameters.

First, the Roesser LSS model with separable denominator is realized in a parallel form. Then the stability condition of the filter is shown. Next, the LMS method is employed to adjust the filter parameters in the parallel form. In addition, the computational time and the number of processors required for the realization are investigated. Finally, the adaptive filter is applied in numerical examples to the 2‐D spatial‐domain filter design and to the noise reduction of an image.
An oversampling subband adaptive digital filter with rational decimation rations
Authors: Kiya Hitoshi , Yamazaki Hirotatsu , Ashihara Koji
Published: July 2007

Recent research has been conducted on the subband adaptive filters wherein filter banks are used in the adaptive filters. However, when a complete reconstruction filter bank is used for subband coding, then the effect of aliasing caused by decimation cannot be avoided in subband adaptive digital filter (ADF). One of the solutions to this problem is the oversampling scheme where maximum decimation is not used. In this paper, a filter bank is proposed that allows us to choose arbitrary rational numbers as decimation ratios. As a special case, they include the integral decimation ratio (which may be considered as the general form of filter bank in oversampling scheme). This filter bank simultaneously maintains the advantages of oversampling scheme and makes possible the realization of a subband adaptive system that has a close to maximum decimation ratio with the reduction of filter order. In this paper, the design conditions of the filter bank are first formulated. Based on these design conditions, one method to design the filter banks is proposed. to confirm the effectiveness of this filter bank, the system identification examples are then simulated.
Use of a priori information in generalized cepstral modeling of degraded speech
Authors: Kanno Toshio , Kobayashi Takao , Imai Satoshi
Published: July 2007

This paper proposes an improved form of generalized cepstral modeling for estimating speech parameters in a noisy environment. The original formulation of the technique based on maximum a posteriori (MAP) estimation procedure uses no a priori information of speech signal. In the improved technique, an initial estimate of speech spectrum is given by using a priori signal‐to‐noise ratio (SNR) and then an iterative procedure is performed.

Several modifications on the iterative procedure also are discussed to reduce residual noise in enhanced speech and spectral distortion of estimated spectrum. A speech enhancement system based on the proposed technique is developed and several experimental results are shown.
Performance prediction of word recognition using the probability of word occurrence
Authors: Otsuki Takashi , Otomo Teruhiko , Ito Akinori , Makino Shozo
Published: July 2007

The words in natural language have different occurrence probabilities. Consequently, the information obtained from the event, i.e., the occurrence of a word, is larger than in the case of the occurrence with uniform probability. In other words, it will be effective to utilize the occurrence probability of the word in the recognition and it is sensible to examine its error‐correcting ability.

This paper considers the situation where the word occurrence probability is used in the word recognition process and presents a method to estimate the relation between the phoneme/character recognition score and the word recognition score. In the past derivation of the evaluation formula for the word recognition score, it is assumed that the word occurrence probability is uniform for whole words and the difference is ignored.

From such a viewpoint, this paper derives the evaluation formula considering the word occurrence probability. By comparing the value estimated by the derived evaluation formula and the value obtained by the simulation for the word recognition, it is found that there is a considerable error due to the approximation and the word recognition score is estimated as approximately 10 percent lower for the phoneme recognition score of 80 percent. Then the approximation procedure is modified and an evaluation formula containing a correction factor is derived. the difference between the value estimated by the corrected evaluation formula and the value obtained by simulation is less than 5 percent for the phoneme recognition score of 80 percent. In other words, the precision is improved and the word recognition score, when the word occurrence probability is utilized, can be estimated accurately.
Method of suppressing burst noise interference in images using smearing‐desmearing transform
Authors: Ohue Kenji , Takabayashi Akifumi
Published: July 2007

To realize high‐quality image transmission and storage, it is important to reduce the effects of the impulsive noise and the image data erasure produced in the transmission and storage. This paper proposes a new method for image noise suppression using the smearing‐desmearing transform.

The smearing‐desmearing transform retains the power spectrum of the image signal and can be applied to the highly efficient coding. the basic principle for the image noise suppression using the smearing‐desmearing transform is shown and the construction of the suitable smearing‐desmearing transform is presented. Then, it is shown that the noise suppression performance of the image noise suppression method based on the smearing‐desmearing transform depends on the variance of the noise, even if there exist the same number of noises. Based on such a property, a method to suppress the burst noise in the image based on the interleaving‐deinter‐leaving and smearing‐desmearing transform is proposed where the smearing‐desmearing transform is applied after spreading the burst noise to fit to the image noise suppression process. Finally, by a computer experiment, it is shown that the proposed method has an excellent effect in image noise suppression.
Design technique of cellular neural network
Authors: Nakai Koji , Ushida Akio
Published: July 2007

The cellular neural network (CNN) is composed of a planar placement of cells which consists of a (piecewise‐linear) nonlinear element and controlled current sources. It features a simple structure which is close to that of the retina and is expected to be utilized in pattern recognition and image processing.

In CNN, each cell is connected to the neighborhood cells by the same pattern, and by adjusting the connection pattern, CNN with various functions can be designed. the connection pattern is called the cloning template. It is very important in the development of new CNN to establish the design method for the cloning template.

In this paper, the operational characteristics are assumed so that the output for the normative input satisfies the specified conditions. the constraint is derived from the specification and the template is designed so that the corresponding cost function is minimized. the simplex method is used as the optimization technique, which features a simple algorithm. As application examples, noise‐remover CNN as well as the maze‐tracing CNN are designed and satisfactory results are obtained. the design method is reported in this paper.