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Volume 119, Issue 7
Displaying 1-24 of 24 articles from this issue
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Atsushi Onae, Takeshi Ikegami, Ken'ichi Nakagawa, Masafumi Koga, Mitsu ...1999 Volume 119 Issue 7 Pages 765-770
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
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Michito Imae, Masami Kihara1999 Volume 119 Issue 7 Pages 771-776
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
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Shin-ichi Ohshima1999 Volume 119 Issue 7 Pages 777-780
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
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Yoshizumi Serizawa, Kazunori Kitamura, Masanori Myoujin, Tohru Matsush ...1999 Volume 119 Issue 7 Pages 781-788
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSA simplified SDH (Synchronous Digital Hierarchy)-based time synchronous system that does not need modification of existing SDH transmission equipment (STE) and clock supply equipment (CSE) is proposed The system has auxiliary time synchronizing equipment (TSE) attached to existing STE and CSE and can be expanded in a cascade and branch manner, where frequency and time are separately synchronized, and which enables us to partially time-synchronize an SDH network or to introduce a time transfer network locally. Experimental time synchronizing devices using a 576-kbps data communication channel (DCC) in the section overhead (SOH) showed potentially satisfactory performance; synchronization errors of a 4-link system are of the order of sub-microseconds. Noise analyses of experimental TSE, DCC, CSE and optical links showed that an accuracy of the order of microseconds will be achieved.View full abstractDownload PDF (1554K) -
Takao Morikawa, Yasusada Ohta, Kenichiro Takahei, Masaro Uehara, Masah ...1999 Volume 119 Issue 7 Pages 789-794
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSFor a space-borne hydrogen maser frequency standard, it is severely required to reduce the size and weight without degrading its excellent frequency stability. To meet these requirements, a small sized microwave cavity with high quality factor is necessary. In this paper, TE011 mode of a small sapphire loaded dielectric cavity for a space-borne hydrogen maser is analyzed and its design principle is discussed. The analysis shows that the frequency stability is optimized when the ratio of the outer diameter of the dielectric tube to the inner diameter of the cavity cylinder is about 0.5. The weight of the physics package is minimized when the diameter and the height of the cavity cylinder are equal to each other. The diameter or the volume of the cavity cylinder is determined by the frequency stability required in the application program.View full abstractDownload PDF (1642K) -
Kenji Hisadome, Masami Kihara1999 Volume 119 Issue 7 Pages 795-801
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThe influence of a stabilized laser's fluctuations in an optically pumped atomic frequency standard is considered. It is important to use a laser with narrow linewidth and to select modulation frequency where the laser's free-running frequency fluctuation at the twice of the modulation frequency is the lowest. Using these considerations, the stabilized laser for our optically pumped cesium beam frequency standard is designedView full abstractDownload PDF (800K) -
Hitoshi Ujiie, Kazuyuki Maruo, Takashi Shimura1999 Volume 119 Issue 7 Pages 802-809
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn the CDMA digital mobile communication network, the system timing of the base stations are generated using GPS Timing and Frequency Reference. It is, however, possible to drop the radio wave in a long tract of time by reason of the location or the failure of the Antenna circuits. In those cases, the reliability of the system will be degraded because of the drift, such as the aging, of the system clock. This paper describes a technique, based on the Wavelet transformation, to reduce the phase error and frequency drift of the GPS Timing and Frequency Reference when the GPS carrier signals could not be received. By simulations and experiments, we have achieved that the phase error is less than 10 microsecond within 48 hour in the state without GPS carrier signals, demonstrating the validity of the proposed technique.View full abstractDownload PDF (954K) -
Yasuaki Watanabe, Naoto Fujita, Kazuhide Shimizu, Shigeyoshi Goka, Hit ...1999 Volume 119 Issue 7 Pages 810-814
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSTo analyze the long-term frequency stability of ultra-stable quartz crystal oscillators, a novel system that continuously measures the stability in both resonant frequencies of the resonators and oscillation frequencies has been proposed. This system enables to estimate the influence of the active circuit conditions upon the resonator aging, and to evaluate the long-term oscillation frequency drift caused by the circuit parts aging. Experimental results using an SC-cut resonator and two distinct Colpitts oscillators show that the long-term resonant frequency drift mainly depends on the amplitude of the crystal driving current and that the aging of the circuit parts affects the long-term frequency stability.View full abstractDownload PDF (1474K) -
Shigenori Mattori, Takanori Saitoh, Shigeru Kinugawa, Koichiro Miyagi1999 Volume 119 Issue 7 Pages 815-820
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSWe have demonstrated active mode-hop suppression in external cavity semiconductor lasers including a wavelength-selecting diffraction grating, based on closed-loop control to nullify the difference between the oscillation wavelength and selected wavelength due to the change in diffraction angle. It reveals that this control suppresses mode-hopping over the span which is 7.5 times the average span without control. Our approach can be adopted for most Littman-type external cavity semiconductor lasers with simple attachments; it will be useful for continuous wavelength sweeping and for long-term wavelength stabilization.View full abstractDownload PDF (1318K) -
Ken Hagimoto, Shin-ichi Ohshima, Yasuhiro Nakadan, Yasuki Koga1999 Volume 119 Issue 7 Pages 821-825
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThe optically pumped cesium (Cs) frequency standard at NRLM (NRLM-4) was developed. We determined the frequency stability by comparing the phase with that of a hydrogen maser: the Allan deviation was σy(τ)=5×10-13/√τ. We estimated the frequency corrections and uncertainties due to various sources, and the total uncertainty was found to be 2.9×10-14. The frequency difference between NRLM-4 and the international atomic time (TAI) was also measured.View full abstractDownload PDF (713K) -
Takahiro Shoji, Takehiko Adachi1999 Volume 119 Issue 7 Pages 826-830
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThis paper presents a fast start-up crystal oscillator circuit. The start-up time depends on the characteristics of the negative resistance of the oscillator circuit. The negative resistance varies in proportion to the emitter bias current. In proposed circuit, the emitter bias resistance is replaced by the control current source and the negative resistance is controlled much bigger than that of the usual oscillator in the initial start-up time by controlling the emitter current. The simulation shows the reduction of the start-up time about one seventh to the usual oscillator circuit.View full abstractDownload PDF (700K) -
Hiroshi Ohno, Takeshi Furuhashi1999 Volume 119 Issue 7 Pages 831-838
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThis paper presents a method for input selection for driver behavior model using neural networks. The selection of inputs can vary under the driver's situations. The driver behavior model is represented by a modular network with the input selection mechanism. The modular network consists of a gating network and some expert networks. The gating network learns from data autonomously the temporal segmentation of behavior which corresponds to driving decisions such as car-following or braking. The expert networks are self-organized corresponding to the behavior. The input selection mechanism consists of driving decision prediction and input selection for driver behavior model. In the experiments using a driving simulator, it was shown that the modular network with input selection mechanism learned the subject behavior from data and the input selection worked for each expert network.View full abstractDownload PDF (1564K) -
Isamu Kajitani, Tsutomu Hoshino, Yuji Hirao, Masaya Iwata, Tetsuya Hig ...1999 Volume 119 Issue 7 Pages 839-847
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSTechnological development of EDA (Electric Design Automation) makes it possible to synthesize circuits by writing their specifications in HDL (Hardware Description Language). This circuit synthesis can be done only when their specifications are made by circuit designers. But it begin to be realized that the necessity of circuit synthesis when we can not make specifications for them. For example, when we want to make high-speed pattern classification circuits for handwritten characters, designers can not make their specifications because of noise on the input character patterns. Therefore we can not use conventional EDA tools for this case. New synthesis method has been proposed which can synthesize circuits in this case by using Genetic Algorithms. In this paper, we propose an acceleration method of this circuit synthesis, because speed of this method is so slow in conventional works. We implemented a proposed method on FPGA (Field Programmable Gate Array) and tested the effect of this method with a V-shape ditch tracer which is a part of a control unit of a welding robot.View full abstractDownload PDF (3226K) -
Tomohiro Hachino, Hitoshi Takata1999 Volume 119 Issue 7 Pages 848-857
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn this paper a new identification algorithm based on a model expanded by a basis of automatic choosing functions (ACF) for continuous-time nonlinear systems is proposed. The Butterworth filter is introduced as a delayed state variable filter, in order to evaluate higher order derivatives of input and output signals. A data region or a whole domain of signals is divided into some subdomains and the unknown nonlinear function to be estimated is approximately represented by a linear local equation on each subdomain. Then these linear local equations are united into a single one by the ACF of sigmoid type smoothly. The resulting model is linear in unknown parameters, which are easily estimated by the least-squares method. The model structure and the state variable filter are properly determined by genetic algorithm. Simulation results are shown to demonstrate the effectiveness of the proposed method.View full abstractDownload PDF (1187K) -
Kenichi Harada, Takashi Matsuoka, Hiroshi Murata1999 Volume 119 Issue 7 Pages 858-867
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn this paper, we propose a new design method of optimal deadbeat servo system with two-degree-of-freedom. In this design method, the desired value tracking characteristics and disturbance rejection characteristics can be performed by different compensators.
The optimal deadbeat control signal which minimizes the quadratic performance index for control signal and deviation can be easily obtained from the matrix computation using sampled data of the step response of the system. Then, the deadbeat controller can be designed by using the control signal.
We show our simulation results with several numerical data to demonstrate the effectiveness of the present method.View full abstractDownload PDF (1562K) -
Fumihiko Saitoh1999 Volume 119 Issue 7 Pages 868-874
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSTo discover a trespasser is an important requirement for security systems in factories or facilities that depend on visual monitoring. To display a fine contrast image is required for reliable visual observation. However, a fine contrast image is not necessarily obtained by changing circumstance where monitoring cameras are set and by changing conditions such as clothes of trespassers. This paper proposes an adaptive method that can enhance the contrast of an image by following the moving object in a scene, since a main object for observation in visual monitoring system is the moving object such as a trespasser. A relation between input and output gray levels that can enhance the contrast of the moving object is determined by a genetic algorithm that evaluates a fitness of an individual using a difference between sequential three frames in an image. The experimental results show that contrasts of moving persons were enhanced effectively in various images for observation using the proposed method.View full abstractDownload PDF (3777K) -
Fujimura Kikuo, Tokutaka Heizo, Ishikawa Masumi1999 Volume 119 Issue 7 Pages 875-882
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSAngeniol et al. applied Kohonen's Self-Organizing Maps (SOM) to solve the traveling salesman problem (TSP) and showed to have a practically enough solution obtained for a short time in comparison to a method depending on a conventional neural network in 1988. We confirmed already that a calculation time is shortened further about TSP of 500 cities, by introducing a momentum effect to the renewal coefficient of original method (Angeniol's, method; SOM-TSP). Here, we report that we evaluated a performance of our improved method about TSP of more large 1000, 2000, 10000 cities.View full abstractDownload PDF (1623K) -
Masahiro Takahashi, Yoshinori Ohkura, Takuji Hamada1999 Volume 119 Issue 7 Pages 883-889
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn a network for an information and control systems, real time communication of large volume data and transmitting multimedia information such as video and voice has been required. In response to realize these requirements, adaption of an ATM (Asynchronous Transfer Mode)-LAN have been investigated This paper describes a loop-type ATM-LAN for control use. In two kinds of system configuration such as a dedicated ATM-switch with a loop mechanism and a general ATM-switch on the market, reliability evaluation of system reconfiguration is investigated As a result, the loop-type ATM-LAN using the dedicated ATM-switch with a loop mechanism is found to be higher reliability and lower connection cost.View full abstractDownload PDF (844K) -
Hirasawa Kotaro, Hu Jinglu, Jin ChunZhi1999 Volume 119 Issue 7 Pages 890-897
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn this paper, a new method named orbital correction to adjust the parameters of the controller of nonlinear systems is presented. Control systems are described by the Universal Learning Network, in which the controller and the controlled object can be dealt with using the same network architecture. And training of the parameters of the controller is carried out by the gradient method. The basic idea of this method is to introduce a kind of a priori information on control performance into the learning process in order to enhance the learning ability. From the simulations of a nonlinear crane control system, it is shown that the proposed method can obtain the better controller than the conventional methods by selecting an appropriate time and volume of orbital correction. And the proposed method may be useful to overcome the local minimum problem always encountered in the gradient method.View full abstractDownload PDF (1128K) -
Hansheng Wu, Shinji Shigemaru1999 Volume 119 Issue 7 Pages 898-905
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThe problem of robust stabilization of a class of time-varying dynamical systems with disturbance and uncertain parameters is considered. The bounds of the disturbance and uncertain parameters are assumed to be unknown. For such uncertain dynamical systems, a class of continuous adaptive robust state feedback controllers are proposed. It is shown that the resulting closed-loop dynamical systems are stable in the sense of uniform ultimate boundedness. A numerical example is given to demonstrate the synthesis procedure for adaptive stabilizing controller proposed in this paper. In particular, by making use of the conventional robust state feedback controllers reported in the control literature, one cannot stabilize the system given in this example. However, by employing the adaptive robust control scheme proposed in this paper, it is possible to stabilize this system.View full abstractDownload PDF (1335K) -
Hiroshi Inoue, Kazuhiko Imano, Kyu-ichiro Terui1999 Volume 119 Issue 7 Pages 906-910
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSMonitoring system is very important technique for the careful management of the condition of patients. Most of the system measures the quantitative information, such as cardiograph, blood pressure and so on. However, the qualitative monitoring including a decubital body motion also gives an important information. In this study, the living information of patients lying on the bed is measured. The direction of patient's body motion is the subject of analysis, and the method for automated recognition of the direction of body motion is suggested. In the experiments, the body motion was detected by the monitoring system as the electrical signal using the PVDF piezoelectric film sensors. The signal from the sensor was transformed into three levels digital signal having zero, +1 and -1 to discriminate the kind of body motion. As the result of experiments, the suggested method successfully discriminates between the longitudinal and transversal direction of body motion on the ordinary bed.View full abstractDownload PDF (1344K) -
Hideki Azuma, Toshikatsu Sonoda1999 Volume 119 Issue 7 Pages 911-912
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThis paper proposes an rms voltage measurement circuit using a thermal converter (TC), which is controlled so as to operate at a constant temperature. Although the input-output characteristics of TCs do not show simple square characteristics, and more over the characteristics of individual TCs are not identical, the proposed circuit has the feature which is independent of the characteristics of individual TCs. Results showed that this circuit had errors of less than 0.07% for voltages of 100 Hz, 20mV-140mV.View full abstractDownload PDF (211K) -
Ryo Kitazawa, Kageo Akizuki, Yuki Nanba, Michio Miyazaki1999 Volume 119 Issue 7 Pages 913-914
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSThis paper proposes the method on dimensional reduction of fuzzy relation represented by the matrix. The main purpose of this method is to save the number of elements of fuzzy relation. This solves the problem of memory shortage which is arisen in multivariable system control. And it is also investigated to decide values of the matrix which represent the desirable system. The search for both solutions is carried out with Genetic Algorithm. Each evaluation function is set appropriately. Finally the proposed method is applied to a simple example and the effect is confirmed.View full abstractDownload PDF (161K) -
Masaki Fukuda, Masafumi Uchida1999 Volume 119 Issue 7 Pages 915-916
Published: July 01, 1999
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSDownload PDF (1113K)
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