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4781-4800hit(4811hit)

  • ACE: A Syntax-Directed Editor Customizable from Examples and Queries

    Yuji TAKADA  Yasubumi SAKAKIBARA  Takeshi OHTANI  

     
    PAPER

      Vol:
    E75-D No:4
      Page(s):
    487-498

    Syntax-directed editors have several advantages in editing programs because programming is guided by the syntax and free from syntax errors. Nevertheless, they are less popular than text editiors. One of the reason is that they force a priori specified editing structures on the user and do not allow him to use his own structure. ACE (Algorithmically Customizable syntax-directed Editor) provides a solution for this problem by using a technique of machine learning; ACE has a special function of customizing the grammar algorithmically and interactively based on the learning method for grammars from examples and queries. The grammar used in the editor is customized through interaction with the user so that the user can edit his program in a more familiar structure. The customizing function has been implemented based on the methods for learning of context-free grammars from structural examples, for which the correctness and the efficiency are proved formally. This guarantees the soundness and the efficiency of customization. Furthermore, ACE can be used as an algorithmic and interactive tool to design grammars, which is required for several purposes such as compiler design and pretty-printer design.

  • Contamination Control in Low-Pressure Process Equipment

    Koichi TSUZUKI  

     
    PAPER

      Vol:
    E75-C No:7
      Page(s):
    860-865

    The motion of particles in low-pressure chemical vapor deposition (LPCVD) (0.4 Torr) equipment has been investigated by a numerical simulation. The effects of wafer orientation, electrostatic forces, and thermophoresis were evaluated. Horizontal surface-down processing and vertical processing can reduce particulate contamination remarkably compared with horizontal surface-up processing. Static electricity control is essential. Weakly charged wafers (several V to several 10 V) can significantly increase submicron particle deposition. In the absence of electrical forces, thermophoresis prevents deposition of particles in the size range 0.03 µmDp0.6 µm, when the temperature difference between the wafer surface and the gas inlet temperature exceeds 100. Deposition of particles smaller than 0.03 µm still occurs by diffusion.

  • Practical Network Planning Support System--PIGEON

    Atsushi MINEGISHI  Yoshihiro DOI  Hikaru MIYAMOTO  

     
    PAPER

      Vol:
    E75-B No:7
      Page(s):
    601-608

    This paper discusses a computer-aided network planning support system called PIGEON that has been developed primarily for advancing countries implementing the applicability to various types of networks and the supportability to the sensitivity analysis. For the implementation of the applicability, the customization by reflecting existing network facilities and their accompanying restrictive conditions into a design result is focused. A case study on the customization shows the effectiveness of the reflection. The procedures are given of the sensitivity analysis in order to examine and to evaluate the effect of the uncertain factors in network planning. In particular, a method called "network modification" is proposed for the sensitivity analysis for uncertain factors associated with a partial network. The network modification efficiently integrates network planner's judgments into a design result by the interactive method. In addition, this paper describes the importance of streamlining the data input and the evaluation of design results, showing the operating time required for each work phase in network planning.

  • Spare-Channel Design Schemes for Self-Healing Networks

    Hideki SAKAUCHI  Yasuyo OKANOUE  Satoshi HASEGAWA  

     
    PAPER

      Vol:
    E75-B No:7
      Page(s):
    624-633

    This paper proposes design schemes which obtain an efficient spare-channel assignment against single and double link failures for a self-healing network. Spare-channel design problems can be formulated as a linear-programming (LP) problem when variables are assumed to be continuous. For the problem, the proposed algorithm effectively solves a sub-set of whole constraints by making use of a maximum-flow algorithm in an iterative manner. It is shown that the maximum number of iteration times is limited by the number of links in the network. Moreover, the relation between the design function and the self-healing function is discussed. It is also shown that the cooperation of the two functions can realize more effective control in large scale networks.

  • Characteristics Analysis of Fibonacci Type SC Transformer

    Ikko HARADA  Fumio UENO  Takahiro INOUE  Ichirou OOTA  

     
    PAPER-Analog-IC Circuit Analysis and Synthesis

      Vol:
    E75-A No:6
      Page(s):
    655-662

    For a realization of a DC-DC converter using no magnetic devices, a new switched capacitor (SC) transformer is introduced, which gives voltage ratios by Fibonacci series corresponding to the stages. This transformer is connected in cascade by each basic block which is assembled by a capacitor and three MOSFET switches. This operates on a simple two-phase clock and has a large step-up or step-down voltage ratio in spite of its simple configuration. The characteristics of this transformer with n stages of basic block are derived and calculated by means of a 4 4 cascade matrix. The optimal arrangement of each stage's capacitances is shown to reduce the SC resistance by about 20%. The simulation results are compared with the characteristics of a prototype transformer with four stages (8 times step-up ratio). Its power efficiency achieves 88% in case of 97 V output voltage, 0.2 A output current, and 100 kHz switching frequency. Lastly, the proposed SC transformer is compared and discussed with other typical SC transformers.

  • Coherent Subcarrier Multiplexed System with Distributing Local Oscillator in Local Loop

    Tomoaki OHTSUKI  Hiroyuki YASHIMA  Iwao SASASE  Shinsaku MORI  

     
    PAPER

      Vol:
    E75-B No:6
      Page(s):
    499-505

    We propose the coherent subcarrier multiplexed (SCM) system with distributing local oscillator (LO) in local loop. The proposed system can realize multichannel transmission with one optical carrier by using the SCM technique and has no need to have LO at each station. Therefore the proposed system becomes cost-effective. The proposed SCM system uses bandpass filter to select a specific channel. We analyze CNR of the system with frequency-shift keying (FSK) in a multioctave configuration. First, the general expression of CNR is derived and is shown for the following parameters such as the number of channels, the position of station on the loop, and the number of stations on the loop. Second, optimal phase modulation (PM) index is derived, and the optimal CNR, minimum required power of lasers, and maximum number of stations that the proposed system can serve are shown by using it. Moreover CNR of the proposed system is compared with that of the system having LO at each station in local loop. It is shown that the proposed system can obtain good performance at the expense of slight increase of the output power of only two lasers at the central station. Therefore the proposed system is cost-effective and practical.

  • 130GHz Frequency Sweep over a 30nm Tuning Range without Mode Hopping by an External-Cavity Semiconductor Laser

    Yasutaka ICHIHASHI  Yoshio NAGAKI  Takeshi TSUKAMOTO  Youichi TAMURA  

     
    LETTER-Optical Communication

      Vol:
    E75-B No:6
      Page(s):
    521-523

    A method for sweeping frequency ranges of over 130GHz within a tuning range of 30nm, without mode hopping, has been realized. The optical frequency is swept with a fine translation-rotation grating drive which uses a new, simplified operation method and a thermally controlled semiconductor laser system.

  • Selection Method of a Flywheel for Digital Measurement System of Torque-Speed Curve

    Kohji HIGUCHI  

     
    LETTER-Instrumentation and Control

      Vol:
    E75-C No:6
      Page(s):
    744-746

    The selection method of the moment of inertia of the flywheel in a digital measurement system of torque-speed curve plotting for a kind of motor is presented. The selection standards of the moment of inertia and the map displaying the operating ranges of the measurement system are shown. The selection procedure of the moment of inertia is also shown.

  • Distortion Free Reconstruction through Phase Conjugation of Holographic Image in Photorefractive Crystal Waveguide

    Fumihiko ITO  Ken-ichi KITAYAMA  

     
    LETTER-Opto-Electronics

      Vol:
    E75-C No:6
      Page(s):
    741-743

    Fourier holographic image storage and reconstruction using BaTiO3 photorefractive crystal waveguide is investigated. The phase conjugation technique, which compensates image distortion caused by modal phase dispersion, successfully retores images stored in a test BaTiO3 crystal waveguide.

  • Large-Signal Parameter Modeling for AlGaAs/GaAs HBT and Its Application to a Monolithic 22 GHz-Band Oscillator

    Nobuyuki HAYAMA  Jun-ichi SHIMIZU  Kazuhiko HONJO  

     
    PAPER

      Vol:
    E75-C No:6
      Page(s):
    683-688

    Design consideration, fabrication process, and performance of a fully monolithic 22 GHz-band oscillator implemented using a self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) are described. For optimization of the oscillator circuit parameters, large-signal circuit model parameters extracted from bias dependent small-signal S-parameters have been used to maximumize an output power. The developed oscillator employs a 1.510 µm2 emitter AlGaAs/GaAs HBT fabricated by using a dual sidewall self-aligned process. The fabricated oscillator has exhibited an output power of 6.2 dBm at 22.16 GHz with a collector efficiency of 9.5%, and phase noise of 78 dBc/Hz at 100 kHz off-carrier under free-running condition. These results were in good agreement with the large-signal designed results obtained using harmonic balance simulator.

  • An Extremely Accurate Quadrature Modulator IC Using Phase Detection Method and Its Application to Multilevel QAM Systems

    Nobuaki IMAI  Hiroyuki KIKUCHI  

     
    PAPER

      Vol:
    E75-C No:6
      Page(s):
    674-682

    An extremely accurate and very wide-band quadrature modulator IC fabricated on a single chip using bipolar technology is presented. The characteristics of this quadrature modulator IC are much superior to conventional ones (modulation phase error and deviation from quadrature is about 1/10), and this IC is applicable to high modulation schemes such as 256 QAM. In this circuit, the phase difference between local signals input to each of two balanced modulators is detected by a phase detector, and a variable phase shifter in the local port is controlled automatically by the detected signals. This, along with the use of a wide-band variable phase shifter, enables the phase difference between the local signals input to the balanced modulators to be adaptively controlled to 90 degrees in wide frequency bands. In addition, a design method for the balanced modulators to obtain small modulation phase error is described. Based on this design method, a highly accurate quadrature modulator IC was fabricated, in which two balanced modulators, the phase detector, and the variable phase shifter were integrated on a single chip. Phase deviation from quadrature in the local signals was reduced to less than 0.3 degrees in the wide frequency bands of more tham 60 MHz. The modulation phase error of the balanced modulators wes less than 0.2 degrees at 140 MHz, and less than 2.5 degrees at up to 1.3 GHz.

  • Passivity and Learnability for Mechanical Systems--A Learning Control Theory for Skill Refinement--

    Suguru ARIMOTO  

     
    INVITED PAPER

      Vol:
    E75-A No:5
      Page(s):
    552-560

    This paper attempts to account for intelligibility of practices-based learning (so-called 'learning control') for skill refinement from the viewpoint of Newtonian mechanics. It is shown from an axiomatic approach that an extended notion of passivity for the residual error dynamics of robots plays a crucial role in their ability of learning. More precisely, it is shown that the exponentially weighted passivity with respect to residual velocity vector and torque vector leads the robot system to the convergence of trajectory tracking errors to zero with repeating practices. For a class of tasks when the endpoint is constrained geometrically on a surface, the problem of convergence of residual tracking errors and residual contact-force errors is also discussed on the basis of passivity analysis.

  • Infinite Dimensional Homotopy Method of Calculating Solutions for Fredholm Operator with Index 1 and A-Proper Operator Equations

    Mitsunori MAKINO  Shin'ichi OISHI  Masahide KASHIWAGI  Kazuo HORIUCHI  

     
    LETTER-Nonlinear Systems

      Vol:
    E75-A No:5
      Page(s):
    613-615

    A type of infinite dimensional homotopy method is considered for numerically calculating a solution curve of a nonlinear functional equation being a Fredholm operator with index 1 and an A-proper operator. In this method, a property of so-called A-proper homotopy plays an important role.

  • A Mean-Separated and Normalized Vector Quantizer with Edge-Adaptive Feedback Estimation and Variable Bit Rates

    Xiping WANG  Shinji OZAWA  

     
    PAPER-Image Processing, Computer Graphics and Pattern Recognition

      Vol:
    E75-D No:3
      Page(s):
    342-351

    This paper proposes a Mean-Separated and Normalized Vector Quantizer with edge-Adaptive Feedback estimation and variable bit rates (AFMSN-VQ). The basic idea of the AFMSN-VQ is to estimate the statistical parameters of each coding block from its previous coded blocks and then use the estimated parameters to normalize the coding block prior to vector quantization. The edge-adaptive feedback estimator utilizes the interblock correlations of edge connectivity and gray level continuity to accurately estimate the mean and standard deviation of the coding block. The rate-variable VQ is to diminish distortion nonuniformity among image blocks of different activities and to improve the reconstruction quality of edges and contours to which the human vision is sensitive. Simulation results show that up to 2.7dB SNR gain of the AFMSN-VQ over the non-adaptive FMSN-VQ and up to 2.2dB over the 1616 ADCT can be achieved at 0.2-1.0 bit/pixel. Furthermore, the AFMSN-VQ shows a comparable coding performance to ADCT-VQ and A-PE-VQ.

  • An NC Algorithm for Computing Canonical Forms of Graphs of Bounded Separator

    Tatsuya AKUTSU  

     
    LETTER

      Vol:
    E75-A No:4
      Page(s):
    512-514

    Lingas developed an NC algorithm for subgraph isomorphism for connected graphs of bounded separator and bounded valence. We present an NC algorithm for computing canonical forms of graphs of bounded separator by using the similar technique.

  • Optimal Task Assignment in Hypercube Networks

    Sang-Young CHO  Cheol-Hoon LEE  Myunghwan KIM  

     
    PAPER

      Vol:
    E75-A No:4
      Page(s):
    504-511

    This paper deals with the problem of assigning tasks to the processors of a multiprocessor system such that the sum of execution and communication costs is minimized. If the number of processors is two, this problem can be solved efficiently using the network flow approach pioneered by Stone. This problem is, however, known to be NP-complete in the general case, and thus intractable for systems with a large number of processors. In this paper, we propose a network flow approach for the task assignment problem in homogeneous hypercube networks, i.e., hypercube networks with functionally identical processors. The task assignment problem for an n-dimensional homogeneous hypercube network of N (=2n) processors and M tasks is first transformed into n two-terminal network flow problems, and then solved in time no worse than O(M3 log N) by applying the Goldberg-Tarjan's maximum flow algorithm on each two-terminal network flow problem.

  • Effect of Reflected Light on Mode Partition Characteristics of Fabry-Perot Laser Diodes

    Akiyuki TAKEDA  Takeshi KAWAI  Masakazu MORI  Toshio GOTO  Akira MIYAUCHI  

     
    PAPER-Optical Communication

      Vol:
    E75-B No:3
      Page(s):
    217-225

    The effect of the externally reflected light on the mode partition characteristics of 1.3 µm Fabry-Perot laser diodes is studied experimentally and numerically. It is observed that the k-value increases monotonically with the DC bias current and the external reflection coefficient. Based on these experimental results, a numerical model to study the mode partition characteristics of laser diodes in the presence of external reflections is developed. The results calculated using this model agree well with the experimental ones. It is found that the mode partition noise is mainly caused by the interference between the light in the laser diode and the reflected light, and also by the fluctuations of the induced emission and absorption. In the time domain, their contribution to the mode partition noise is almost localized in the time region within 0.1nsec at the time when the optical pulse turns on.

  • A BiCMOS Analog Neural Network with Dynamically Updated Weights

    Takayuki MORISHITA  Youichi TAMURA  Tatsuo OTSUKI  Gota KANO  

     
    PAPER

      Vol:
    E75-C No:3
      Page(s):
    297-302

    We have developed a 64-neuron electrically trainable BiCMOS analog neuroprocessor based on 3-layered PDP networks with a feedforward time as short as 10 µs which is equivalent to the operation speed as high as 108 multiplications per second. A crucial point in this development is application of a dynamic refreshment technique to a weighting circuit. A sufficiently long retention time of the synapse weight has thereby been attained, leading to a practical operation of the neuroprocessor.

  • Distributed Signal Transmission System Using Discrete Fourier Transform for High Noise Immunity

    Hyunkoo KANG  Yoon UH  Tasuku TAKAGI  

     
    PAPER

      Vol:
    E75-B No:3
      Page(s):
    188-192

    We propose a new distributed signal (analog or digital) transmission system which has the immunity against the noisy channel. An information signal in transmitter is distributed by distributor and the distributed signal is transmitted. Received signal is reconstructed by the inverse distributor in receiver. In this system, an impulsive interference noise which disturbs the transmission signal in the channel passes decoder only, and this interference noise is distributed by the inverse distributor while the transmitted signal is reconstructed. Some appended signals make it possible to estimate the noise components which inversely distributed with the Fourier transformation as the distributor. Basing upon this principle, the transmission system will have an ability to suppress the impulsive interference, and the channel will have high noise immunity. The construction of receiver which can eliminate the impulsive noise is derived.

  • A Simple Hyperchaos Generator Including One Ideal Diode

    Toshimichi SAITO  

     
    INVITED PAPER

      Vol:
    E75-A No:3
      Page(s):
    294-298

    This article proposes a four dimensional autonomous hyperchaos generator whose nonlinear element is only one diode. The circuit is analyzed by regarding the diode as an ideal switch. Hence we can derive the two dimensional return map rigorously and its Lyapunov exponents confirm the hyperchaos generation. Also, a novel mathematical basis for the simplification to the ideal switch is given.

4781-4800hit(4811hit)