IEEJ Transactions on Electronics, Information and Systems
Online ISSN : 1348-8155
Print ISSN : 0385-4221
ISSN-L : 0385-4221
Volume 117 , Issue 11
Showing 1-27 articles out of 27 articles from the selected issue
  • Sumio Masuda
    1997 Volume 117 Issue 11 Pages 1539
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • TETSUO INOUE
    1997 Volume 117 Issue 11 Pages 1540-1546
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Charge simulation method has been applied to solve partially differential equations in electorical engineering. In this paper, a new sheme in the charge simulation method is proposed for interior 2-domensional Dirichlet problems, based on potentially theoretical considerations(1), (2). The scheme has mathematically superior characteristics, comparing to the conventional one. Typical examples show that numerical results of high accuracy may be obtained by the new method.
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  • Tatsuya Masuda, Hideaki Moriya, Naritatsu Yamamoto, Hiroshi Matoba, Sh ...
    1997 Volume 117 Issue 11 Pages 1547-1556
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Distribution system loss minimization re-configuration is a 0-1 planning problem that determines the disconnected positions of section switches, and the number of conbinations requiring searches is extermely large when dealing with typical system scales. For this reason, it is considered that the application of a genetic algorithm (GA) is effective means to solve this problem, and some methods using the standard GA have been proposed. The search efficency of these methods, however, is unsatisfactory because a large number of infeasible combinations (i.e., lethal genes) of section switches exist in practical scale system.
    In this paper, to solve the problem, we show four necessary conditions which feasible solution of the distribution system must satisfy. Continually, we propose a new method for distribution system loss minimization re-configuration by the improved GA controlling the incidence of lethal gene. In this method, we devise for the above four necessary conditions to be satisfied at each genetic operation.
    Simulations are carried out using two distribution systems to demonstrate the proposed method's effectiveness and practicality.
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  • Shinji Tsuzuki, Yoshio Yamada, Saburo Tazaki, Susumu Yoshida
    1997 Volume 117 Issue 11 Pages 1557-1565
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The variation of packet arrival time is one of the problems to be solved in realizing the real-time voice communication on asynchronous networks such as Internet. Although the variation can be absorbed by means of a receiving buffer, the end-to-end delay increases in proportion to the buffer size. Therefore, the guideline for the receiving buffer's design which considers the tradeoff between voice quality and delay is needed.
    In this paper, the design of the receiving buffer by using the voice speed conversion technique is discussed. The buffer size should be equivalent to the time length of about 95_??_99% of the probability distribution function of the packet arrival intervals. However, the synchronized voice reproducing can be achieved with the preset delay, which is shorter than the corresponding time to the buffer size, by controlling the rate of voice speed conversion within the range of 50%_??_150% depending on the variation of the intervals. The proposed buffer design was implemented in the conventional non-real-time UNIX workstations (WSs) connected to Ethernet and its performance was measured. The average voice delay between WSs for the authors' scenario is 150_??_180msec and the synchronization is achieved with the standard deviation of 13_??_25msec. The proposed method is applied to VSAT satellite channel routers to realize the real-time voice communication between the WSs via the VSAT channel.
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  • Katsuyuki Majima, Toshimasa Miyazaki, Kiyoshi Ohishi
    1997 Volume 117 Issue 11 Pages 1566-1572
    Published: October 20, 1997
    Released: December 19, 2008
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    This paper proposes a new dynamic gait control method of biped robot based on robust joint servo control. The method consists of two subjects. The first subject is the approximation of biped robot to the inverted pendulum for sagittal plane and lateral plane. The second subject is the constitution of dynamic gait control based on robust joint servo control and kinematics.
    The motion description in Cartesian space is determined from the motion of the inverted pendulum for sagittal plane and lateral plane. Suitability of the biped motion reference is confirmed by distribution of ZMP (Zero Moment Point). Using the inverse kinematics of biped robot, the biped motion references in Cartesian space is transformed to the position references in joint space. In joint space, the robust position control system consists of two-degrees-of-freedom control system based on coprime factorization and disturbance observer. Since the robust joint servo control system compensates the inertia variation and disturbance torque on dynamic gait control, this control system is suitable for the dynamic gait control of biped robot. The validity of the proposed method is confirmed by the experimental results.
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  • Shinji Noguchi, Kazuaki Kagamihara, Takuya Kamano, Takayuki Suzuki, Ta ...
    1997 Volume 117 Issue 11 Pages 1573-1579
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In general, it is difficult to operate construction machines because of nonlinear characteristics of hydraulic actuators and its complicated mechanical structures. Therefore, automation and simplification of the construction machines are very important from the viewpoint of reducing the operators load.
    In this paper, an application of self-tuning fuzzy control scheme for complex operation of an aerial working platform is described. The selftuning fuzzy controller acts as a feedfoward controller in each driving axis to improve the tracking performances. Furthermore, a cooperative controller is introduced to achieve high accuracy vertical and horizontal movements. The fuzzy rules are adjusted by a tuning law so that both tracking error in each axis and cooperation error are reduced. The effectiveness of the proposed control system for improvement of tracking performance and accurate vertical and horizontal movements is demonstrated by experiment.
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  • Toshiji Kato, Shigekazu Fujimoto
    1997 Volume 117 Issue 11 Pages 1580-1585
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper proposes a new efficient method which solves mixed circuit equations of a power electronic system by utilizing element characteristics not only of main and control circuits but also of digital and analog elements. First, formulated circuit equations are divided into the minimum units of circuit block groups. Then the groups are scheduled and solved sequentially according to order of their signal flows. The method is applied to analysis of two example power converters. Computed results showed reduction of circuit equation sizes and efficiency of numerical iteration processes.
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  • Toshihiro Kamiya, Akira Beppu, Shinji Kusumoto, Katsuro Inoue, Yukio M ...
    1997 Volume 117 Issue 11 Pages 1586-1592
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Measuring software product and the development process is essential for improving software productivity and quality. Software metrics are quantitative measures of software products and process. For example, complexity metrics are used to evaluate maintenance difficulty of a program. In order to evaluate the complexity of object-oriented program, several complexity metrics have been proposed. Among them, Chidamber and Kemerer's metrics are the most well-known metrics for object-oriented programs. Also, their effectiveness for estimating the number of faults in a program has been evaluated empirically. However, from the viewpoint of the management, it is more important to estimate the cost to fix the faults in the program rather than the number of ones. This paper empirically evaluates the usefulness of Chidamber's metrics by examining the relationship between the value of the metrics and the cost to fix the faults in the program by using the data collected from actual software development processes. This paper also examines how to apply the metrics to the programs most of which is developed by reusing the classes in the class-library (framework).
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  • Shigeo Morimoto, Akira Hamamoto, Yoji Takeda
    1997 Volume 117 Issue 11 Pages 1593-1599
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In some industrial motor drive systems, a torsional vibration is often generated because of an elastic element in torque transmission. Such mechanical system is modeled as a two-mass-system and it is well-known that the suppressing vibration of a low inertia ratio two-mass system where the motor inertia is larger than the load inertia is very difficult. This paper proposes a speed control system of a low inertia ratio system taking not only the dynamic responses but also a robust stability into account. The proposed control system based on the H control theory and the resonance ratio control due to the feedback of the estimated shaft torque. Combining the H controller with the resonance ratio controller, the control system with high robust stability can be obtained comparing with the conventional resonance ratio control. The variable feedback gain system and the construction of the disturbance observer are discussed in order to reject the effects of noise. The simulated and experimental results show that the proposed speed control system is useful for the two-mass-system with low inertia ratio.
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  • Sanae Murotani, Masamichi Nakamura, Komyo Kariya
    1997 Volume 117 Issue 11 Pages 1600-1606
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This study has discussed as a task on modeling of uncertain phenomena in the study of construction of measurement science which is intended to be a standard science of each scientific field. In this paper, numerical expression model of electrode discharge phenomena is indicated as the time transition (TT) model, because the electrode discharge current value and its statistical dispersion by time transition show a fixed tendency of saying as relating to the peculiar parameters of electrode materials. And the usefulness of applying to the changing of state and situation that exists on society is discussed by referring “Replicon model” on group biology.
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  • Michio Umeda, Yuujirou Hama
    1997 Volume 117 Issue 11 Pages 1607-1614
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this paper, we first recognize individual character in the prefecture/city part of mail addresses, followed by inferring the entire prefecture/city parts. Then we extend the character category set and recognize entire mail addresses. As pre-processing steps, correction of the characters' stroke widths and orientations is also carried out. This method attempts to improve the recognition rate for individual character as well as the recognition rate for mail address character strings. By using the proposed method, a rate of 85.4% of correctly recognized addresses was achieved in experiments utilizing data distributed by the Research Institute of the Ministry of Postal Affairs.
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  • Junji Fukumi, Takuya Kamano, Takayuki Suzuki, Takashi Yasuno, Yu Katao ...
    1997 Volume 117 Issue 11 Pages 1615-1622
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this paper, two types of fuzzy two-degree-of-freedom positioning systems are considered. One is a system which consists of a self-tuning fuzzy feedforward controller (STFC) and a fixed rules fuzzy feedback controller (FBC). The control rules of the STFC are automatically adjusted by a tuning law, the objective of which is to make an equivalent dynamic inverse of a nonlinear plant after tuning. The rules of the FBC are tuned in advance so that the FBC acts as a high gain feedback controller to restrain the effect of disturbance input. The other consists of the STFC and a fuzzy disturbance observer (FDO). The same rules of the STFC which provide the equivalent dynamic inverse are used in the FDO to estimate the disturbance input. To ensure the validity of the proposed systems, the responses of a positioning system with a progressive wave type ultrasonic motor (PUM) are measured. Experimental results demonstrate the effectiveness of the systems for improvement of the tracking performances and robustness.
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  • Toshiji Kato, Takeshi Kataoka
    1997 Volume 117 Issue 11 Pages 1623-1628
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper proposes a new multirate analysis method which selects a proper numerical integration stepsize for each variable in analyzing a circuit which has subcircuits with different rates. First a formulation technique of multirate circuit equations is derived. Then a rate classification technique is derived from the error estimation formula of the Backward Differetiation Formulas (BDF). Further a stepsize adjustment technique at a break point is explained. Finally the proposed method is applied to a basic filter and a DC-DC converter circuits which showed efficiency of the method.
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  • Tomofumi YOSHIDA, Noriaki MURANAKA, Shigeru IMANISHI
    1997 Volume 117 Issue 11 Pages 1629-1634
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Technique of virtual reality has been becoming popular in various fields including education because of its remarkable technique progress. There are the three useful elements of “presence”, “interaction” and “autonomy” in realizing the virtual reality. Here, we are focusing on the “presence” in constructing a simple supporting system for calligraphy education. We take advantage of the virtual image with reality to use as an educational interface because the virtual image and the real image are overlapped by showing the visual scene in the system.
    It is general that the unity of the virtual image and the real image has been processed as the stationary pictures by using “See-through HMD” and so on. In this paper, by using half mirror in stead of using the HMD with restraint, we are released from its restrainable sense. The virtual image and the real image are laid to overlap as the mobile pictures. The virtual hand replays the character inputted on the tablet by the excellent calligrapher. A calligraphic trainee is practicing overlapping the virtual hand which is reflected at the half mirror, while the trainee is doing the character on the tablet in the handwriting. The trainee is repeatedly practicing with feedback and is getting better in handwriting the character. It is shown in the good expermental results that the system has a proven effectiveness.
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  • Hiroki Tashima, Katsumi Harashima, Kunio Fukunaga
    1997 Volume 117 Issue 11 Pages 1635-1642
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In high level synthesis, Scheduling is an important stage which assigns each operation appeared in a data flow graph to a specific control step, of which results influence the design quality directly. This paper describes a scheduling approach for pipelined datapaths. Since few previous approaches estimate the inter connection cost between registers (register-to-register cost), our approach introduces a datapath model with the interconnection between registers across buses, and minimizes the total hardware cost including the register-to-register cost with the Force-Directed Scheduling.
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  • Koji EGUCHI, Hidetaka ITO, Akira KUMAMOTO
    1997 Volume 117 Issue 11 Pages 1643-1649
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The recent growth of information resources on the WWW has led to the increasing need for developing flexible methods of information retrieval. Since the behaviors of users of WWW information retrieval systems naturally reflect the complex hypertext structure of the WWW pages written from various viewpoints, it is desirable that the systems should be able to track various dynamic changes in the intensions of the users. Most of conventional techniques of information retrieval, which typically assume that the users have precise and fixed goals, are not suitable for realizing the desired features for WWW information retrieval systems. In this paper, we propose a new extension to the relevance feedback and demonstrate its adaptability to a wide variety of the behavior of users.
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  • Takahiro Yamasaki, Masaki Yumoto, Takenao Ohkawa, Norihisa Komoda, Fus ...
    1997 Volume 117 Issue 11 Pages 1650-1656
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Stochastic qualitative reasoning is one of key technologies for the model based fault detection, in which a part in failure is identified by comparing the results of reasoning with the real measured values. However, since a model must be constructed with many stochastic parameters, the parameter tuning process is one of the most difficult problem in model generation. In addition, generated models can be only validated by human intuition.
    This paper proposes an approach to automatic parameter tuning in order to solve this problem. First, propagation rules and functions in a model are formalized with several characteristic parameters. Next, we have proposed a method for automatic parameter tuning by the steepest ascent based method. In automatic parameter tuning, because most of the processing time is spent calculating agreement rate, the idea to decrease reasoning times are proposed. Finally, this method is applied to a real air conditioning system in a building. As a results, we verify the model with the averaged parameters satisfies the behaviors for a target system for given terms.
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  • Hirofumi Fujita, Yasuharu Ohsawa
    1997 Volume 117 Issue 11 Pages 1657-1663
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this paper, examined is the modeling of power system dynamics through the direct approximation of power system input/output mapping by neural network (NN) instead of through the conventional method by differential equations. The NN used is of multilayer type with delayed signals, which is suitable for dealing with time series data, and it is trained by the error back propagation algorithm. Two sample systems are modeled by the NN; one is a numerical simulation model, and the other is an experimental system, both of which are a one-machine infinite-bus system. The input signal and the output signal to the NN are the reference value of the generator terminal voltage and the terminal voltage itself, respectively. The parameters in the learning algorithm are adjusted so that the training develop smoothly and converge in 30, 000 times for the numerical simulation model. Thus obtained values of parameters are used for the identification of the experimental system, and the development of training is evaluated. NNs with different input structure are trained for both sample systems, and high approximation accuracy was found achieved. The performance of the NN trained by the experimental system data is compared with that of the conventional differential equation model, and the possibility of the power system dynamics modeling by NN is shown.
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  • Ryuji Mano, Takuya Tsuyuguchi, Isao Mizoshiri, Satoshi Hirasaki, Hiroy ...
    1997 Volume 117 Issue 11 Pages 1664-1669
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Many of methods already proposed observe a global motion of a outline of a cardiac muscle. MR Images (MRI) may observe the local motion of the cardiac muscle as the motion of tags.
    In this paper, we propose a method to detect borders of tags in tagging MRI as meshed images using an active net. An image fitting energy of the active net decay with time compared with a distortion energy of the active net, since density and contrast of MRI fade out with time. The energy ill-balance causes decreases in the ability of the
    active net. The active net is composed as the image fitting energy to keep the same contrast over a cardiac systole cycle. A behavior of detected meshed images represent a motion of cardiac muscle precisely, and play important roll of an assessment of a myocardial function and diagnosisses of heart diseases.
    Finally, a usefulness of this method is shown by applying to a critical example.
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  • Takayuki Hiraoka, Naoki Kagawa, Ming Wang, Osami Wada, Ryuji Koga
    1997 Volume 117 Issue 11 Pages 1670-1676
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A tunable diode laser absorption spectrometry (TDLAS) system has been developed in order to apply it to an open atmospheric path which is often suffered from heavy scintillation. A quick scanning of the laser frequency and the digital signal processing architecture are employed to cope with it. The laser frequency is scanned over 4 ms around an absorption line of CH4 in 7μm band every 31ms.
    Received signal is treated with a DSP system to achieve the best SNR and also to separate the absorption signal from scintillation. Column density of CH4 is produced on every laser frequency scanning. The adjoint spectrum algorithm is employed to achieve the separating capability.
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  • Masaru Teranishi, Sigeru Omatu, Toshihisa Kosaka
    1997 Volume 117 Issue 11 Pages 1677-1681
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper is concerned with bill money classification between new and used bills based on acoustic data by neural networks. The acoustic data is measured by a microphone located inside a banking machine. We propose a method to extract the spectral density of bill money acoustic data from the measured data which contains both bill sound and motor sound by the banking machine. The extraction method is based on the relation of correlation functions. Applying the FFT to the correlation functions, we can extract the spectral data of only bill money. From the spectral data, we classify the bill into new or used one. The proposed method by neural networks presents better classification performance than a template matching classification method.
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  • Michifumi Yoshioka, Sigeru Omatu
    1997 Volume 117 Issue 11 Pages 1682-1687
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In recent years, many methods for image compression have been proposed. Especially, JPEG and MPEG have achieved high compression ratio while these can not recover the original images completely. In these methods, image data are reduced in spatial frequency domain according to a human eye property. In this study, we have developed a new method to reduce image data with noise components in the image using an Independent Component Analysis (ICA). An advantage of this method is to preserve quality of the image by reducing the noise which is independent of the original image data.
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  • Hidetoshi Wakamatsu, Xiaolin Zhang
    1997 Volume 117 Issue 11 Pages 1688-1695
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In order to realize basic optic axis movements, by which a moving target can be caught in a central pit of retina, an oculomotor mathematical model is developed for horizontal movements of a head and an eyeball. An image signal from retina and an acceleration signal from semicircular ducts are used as control inputs to muscles of eyeball to realize appropriate eye movements taking into account the displacement of a head rotation. Reflex eye movements and smooth pursuit as autokinesis are discussed with consideration of their control perfomances which lead to automatic cooperation of an appropriate control system according to the movement types of an target. The optic axis is controlled by a unified eye movement system which is synthesized on the basis of various biological facts. It has a flexible dynamics characterized by variable parameters which imply anatomical structure and physiological mechanism given by the change of synaptic conductivities in flocculus. The basic physiological facts are presented under the corresponding anatomical and physiological conditions given by appropriate changes of mathematical description of the proposed model.
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  • Takashi Hasegawa, Makoto Fujii, Takeshi Furuhasi, Yoshiki Uchikawa
    1997 Volume 117 Issue 11 Pages 1696-1701
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    It is easy for humans to communicate with each other using natural language. If a system was capable of understanding linguistic instructions given by human operators, the system will be easy to use in a complex environment. However linguistic instructions are usually vague and their meanings depends on the circumstances. There are gaps between the linguistic expressions and the desired behavior of the system in many cases.
    This paper presents a new system for behavior improvement through understanding of linguistic instructions using a fuzzy classifier system. The proposed method can autonomously acquire the meanings of instructions. Simulations are done to demonstrate the capability of the proposed method.
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  • Kenichiro Hayashi, Akifumi Otsubo
    1997 Volume 117 Issue 11 Pages 1702-1709
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    One of the important concept in fuzzy control is fuzzy inference, and the “simplified inference method” which is aimed at increasing the speed of the fuzzy inference has recently been used to realize a high-speed fuzzy controller. In designing a fuzzy controller, a high dimension such as 7×7 or 5×5 partitions is frequently used for the number of fuzzy labelings. However, as the number of fuzzy labelings increases, the number of control parameters increases rapidly and tuning of the fuzzy controller becomes difficult. Therefore, a fuzzy controller is required to be partitioned into a low-dimensional number of fuzzy labelings such as 3×3 partitions.
    With this in mind, first, a method of improving the control performance for a low-dimensional number of fuzzy labelings using the “simplified inference method” which enables high-speed inference is proposed in this paper. Next, the effectiveness of this improvement method is investigated based on the results of several simulations where a first-order lag system with dead time, which is a representative model for plant characteristics, is used as the controlled system.
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  • Takashi Homma, Takao Watanabe, Keiichiro Yasuda
    1997 Volume 117 Issue 11 Pages 1710-1718
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Genetic Algorithms (GAs) are the optimization technique, which simulate the process of the heredity and the natural selection in the animate nature. In GAs, the diversity of the population is often lost in the process of searching. When the diversity is lost, the search efficiency gets worse. In this paper, we propose a new method to preserve the diversity of the population, which is based on the model called frequency dependent selection in population genetics. In this method, the fitness value of a chromosome with rare allele is increased according to the allelic frequency. To show the effectiveness of the proposed method, we compare the GA to which the proposed method is introduced with the Simple GA in knapsack problem as a test. Furthermore, we compare the GA using the proposed method with the GA using the sharing method and the GA using the method proposed by Ichikawa and Ishii.
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  • Kenta Yuki, Michio Miyazak
    1997 Volume 117 Issue 11 Pages 1719-1720
    Published: October 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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