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[Keyword] LD(1872hit)

1821-1840hit(1872hit)

  • Morphology Based Thresholding for Character Extraction

    Yasuko TAKAHASHI  Akio SHIO  Kenichiro ISHII  

     
    PAPER

      Vol:
    E76-D No:10
      Page(s):
    1208-1215

    The character binarization method MTC is developed for enhancing the recognition of characters in general outdoor images. Such recognition is traditionally difficult because of the influence of illumination changes, especially strong shadow, and also changes in character, such as apparent character sizes. One way to overcome such difficulties is to restrict objects to be processed by using strong hypotheses, such as type of object, object orientation and distance. Several systems for automatic license plate reading are being developed using such strong hypotheses. However. their strong assumptions limit their applications and complicate the extension of the systems. The MTC method assumes the most reasonable hypotheses possible for characters: they occupy plane areas, consist of narrow lines, and external shadow is considerably larger than character lines. The first step is to eliminate the effect of local brightness changes by enhancing feature including characters. This is achieved by applying mathematical morphology by using a logarithmic function. The enhanced gray-scale image is then binarized. Accurate binarization is achieved because local thresholds are determined from the edges detected in the image. The MTC method yields stable binary results under illumination changes, and, consequently, ensures high character reading rates. This is confirmed with a large number of images collected under a wide variety of weather conditions. It is also shown experimentally that MTC permits stable recognition rate even if the characters vary in size.

  • Effect of Field-Dependent Diffusion Coefficient in QWITT Diodes

    Makoto FUKUSHIMA  

     
    LETTER-Semiconductor Materials and Devices

      Vol:
    E76-C No:9
      Page(s):
    1420-1422

    The small-signal negative resistance of QWITT (Quantum Well Transit-Time) diodes is calculated including the effect of field-dependent diffusion coefficient in the frequency range of 10 to 300 GHz. The drift velocity transient effect is also included. The result is compared with those obtained by using constant diffusion coefficients at average electric fields.

  • Sampling Theorem: A Unified Outlook on Information Theory, Block and Convolutional Codes

    Farokh MARVASTI  Mohammed NAFIE  

     
    PAPER

      Vol:
    E76-A No:9
      Page(s):
    1383-1391

    Redundancy is introduced by sampling a bandlimited signal at a higher rate than the Nyquist rate. In the cases of erasures due to fading or jamming, the samples are discarded. Therefore, what we get at the output of the receiver is a set if nonuniform samples obtained from a uniform sampling process with missing samples. As long as the rate of nonuniform samples is higher than the Nyquist rate, the original signal can be recovered with no errors. The sampling theorem can be shown to be equivalent to the fundamental theorem of information theory. This oversampling technique is also equivalent to a convolutional code of infinite constraint length is the Field of real numbers. A DSP implementation of this technique is through the use of a Discrete Fourier Transform (DFT), which happens to be equivalent to block codes in the field of real numbers. An iterative decoder has been proposed for erasure and impulsive noise, which also works with moderate amount of additive random noise. The iterative method is very simple and efficient consisting of modules of Fast Fourier Transforms (FFT) and Inverse FFT's. We also suggest a non-linear iterative method which converges faster than the successive approximation. This iterative decoder can be implemented in a feedback configuration. Besides FFT, other discrete transforms such as Discrete Cosine Transform, Discrete Sine Transform, Discrete Hartley Transform, and Discrete Wavelet Transform are used. The results are comparable to FFT with the advantage of working in the field of real numbers.

  • A New Neural Network Algorithm with the Orthogonal Optimized Parameters to Solve the Optimal Problems

    Dao Heng YU  Jiyou JIA  Shinsaku MORI  

     
    PAPER-Neural Networks

      Vol:
    E76-A No:9
      Page(s):
    1520-1526

    In this paper, a definitce relation between the TSP's optimal solution and the attracting region in the parameters space of TSP's energy function is discovered. An many attracting region relating to the global optimal solution for TSP is founded. Then a neural network algorithm with the optimized parameters by using Orthogonal Array Table Method is proposed and used to solve the Travelling Salesman Problem (TSP) for 30, 31 and 300 cities and Map-coloring Problem (MCP). These results are very satisfactory.

  • Single b-Bit Byte Error Correcting and Double Bit Error Detecting Codes for High-Speed Memory Systems

    Eiji FUJIWARA  Mitsuru HAMADA  

     
    PAPER

      Vol:
    E76-A No:9
      Page(s):
    1442-1448

    This paper proposes new design methods for single b-bit (b2) byte error correcting and double bit error detecting code, called SbEC-DED code, suitable for high-speed memory systems using byte organized RAM chips. This new type of byte error control code is practical from the viewpoint of having less redundancy and stronger error control capability than the existing ones. A code design method using elements from a coset of subfield under addition gives the practical SbEC-DED code with 64 information bits and 4-bit byte length which has the same check-bit length, 12 bits, as that of the Hamming single byte error correcting code. This also has very high error detection capabilities of random double byte errors and of random triple bit errors.

  • Investigation on the Possible Electric Field Effect and Surface Morphology of a YBCO/CeO2/Au MIS Diode

    Qian WANG  Ienari IGUCHI  

     
    PAPER

      Vol:
    E76-C No:8
      Page(s):
    1271-1274

    A YBCO/CeO2/Au MIS structure (YBCO:YBa2Cu3O7y) is fabricated on a MgO(100) substrate with the help of the all-in-situ electron-beam and heater coevaperation system. The current-voltage (I-V) characteristics of the deposited YBCO film under various gate voltages are examined. Small modulation of the I-V characteristics by gate voltages can be observed. Meanwhile, the surface morphology is also studied by means of an atomic force microscope (AFM). The relation between the field effect and the surface morphology of a thin YBCO film is discussed.

  • Performance of Asynchronous Band-Limited DS/SSMA Systems

    Takafumi SHIBATA  Masaaki KATAYAMA  Akira OGAWA  

     
    PAPER

      Vol:
    E76-B No:8
      Page(s):
    921-928

    This paper discusses the performance of asynchronous direct-sequence spread-spectrum multiple-access systems using binary or quaternary phase-shift keyed signals with the strict bandwidth-limitation by Nyquist filtering. The signal-to-noise plus interference ratio (SNIR) at the output from the correlation receiver is derived analytically taking the cross-correlation characteristics of spreading sequences into account, and also an approximated SNIR of a simple form is presented for the systems employing Gold sequences. Based on the analyzed result of SNIR, bit error rate performance and spectral efficiency are also estimated.

  • Experiment and Arnold Theory Analysis of Excess Current due to Andreev Reflection

    Shigeru YOSHIMORI  Wataru NAKAHAMA  Mitsuo KAWAMURA  

     
    PAPER

      Vol:
    E76-C No:8
      Page(s):
    1319-1324

    Experimental results of an N-S junction and analysis of the results using the Arnold theory were reported. Au and Pb were employed as a normal metal and a superconducting material, respectively. The excess current effect due to the Andreev reflection was observed in the current-voltage characteristics of an N-S junction whose normal resistance was 1.603 Ω. The excess current at 4.62 K was about 0.7 mA when the applied voltage was 2 mV. The barrier height and width were estimated to be 1.0169 eV and 0.7 , respectively, by comparing the experimental results and analysis based on the Arnold theory. In the voltage region less than 2 mV, the theory well agreed with the experiment. Moreover, the applied voltage dependence of the supercurrent and quasiparticle current were separately calculated. It was made clear that the supercurrent was larger than the quasiparticle current in the voltage region less than 2Δ/e, where Δ is the superconducting energy gap and e is the absolute value of an electron's charge. The supercurrent began to gradually saturate when the voltage was higher than Δ/e and became constant at the applied voltage greater than 2Δ/e. In our experiment, the excess current larger than expected from the Arnold theory was observed in the voltage region higher than 2Δ/e.

  • Magnetic Shields for HTc SQUIDs

    Kumiko IMAI  Hironori MATSUBA  Peter SPEAR  Alistair FIFE  

     
    PAPER

      Vol:
    E76-C No:8
      Page(s):
    1280-1286

    Bi2Sr2Ca1Cu2Ox thick film superconducting shields have been fabricated for use with HTc SQUIDs. Shielding factors and internal noise levels of the shields were measured using a DC SQUID magnetometer. A sample in which BSCCO was coated on the outside of a cylindrical Ag substrate exhibited larger noise levels than that with a sample in which BSCCO was coated on the inside of the Ag cylinder. The difference is explained by the thermally driven (Johnson) noise from the Ag substrate. A sample with the Ag cylinder outside the superconductor and samples with MgO substrates inside the superconductor showed good performance with a shielding factors of 10-8 and internal noise levels which did not exceed the DC SQUID magnetometer resolution (5 fTrms/Hz) at 4.2 K. In addition, the flux relaxation noise of BSCCO superconducting shields was estimated from the relaxation behavior of BSCCO.

  • A Real-Time Scheduler Using Neural Networks for Scheduling Independent and Nonpreemptable Tasks with Deadlines and Resource Requirements

    Ruck THAWONMAS  Norio SHIRATORI  Shoichi NOGUCHI  

     
    PAPER-Bio-Cybernetics

      Vol:
    E76-D No:8
      Page(s):
    947-955

    This paper describes a neural network scheduler for scheduling independent and nonpreemptable tasks with deadlines and resource requirements in critical real-time applications, in which a schedule is to be obtained within a short time span. The proposed neural network scheduler is an integrate model of two Hopfield-Tank neural network medels. To cope with deadlines, a heuristic policy which is modified from the earliest deadling policy is embodied into the proposed model. Computer simulations show that the proposed neural network scheduler has a promising performance, with regard to the probability of generating a feasible schedule, compared with a scheduler that executes a conventional algorithm performing the earliest deadline policy.

  • Correlation between Spatial Distributions of Surface-SAR and Magnetic Near-Field in Realistic Head Model for Microwave Exposure

    Osamu FUJIWARA  Michihiko NOMURA  

     
    LETTER

      Vol:
    E76-B No:7
      Page(s):
    765-767

    Correlation between the surface-SAR and external magnetic near-field in a realistic head model for 1.5GHz microwave far-field exposure is described. The regression relation is shown between the one gram averaged SAR and squared external magnetic field on the cross sectional perimeter of the head model.

  • Deterministic Boltzmann Machine Learning Improved for Analog LSI Implementation

    Takashi MORIE  Yoshihito AMEMIYA  

     
    PAPER-Neural Networks and Chips

      Vol:
    E76-C No:7
      Page(s):
    1167-1173

    This paper describes the learning performance of the deterministic Boltzmann machine (DBM), which is a promising neural network model suitable for analog LSI implementation. (i) A new learning procedure suitable for LSI implementation is proposed. This is fully-on-line learning in which different sample patterns are presented in consecutive clamped and free phases and the weights are modified in each phase. This procedure is implemented without extra memories for learning operation, and reduces the chip area and power consumption for learning by 50 percent. (ii) Learning in a layer-type DBM with one output unit has characteristic local minima which reduce the effective number of available hidden units. Effective methods to avoid reaching these local minima are proposed. (iii) Although DBM learning is not suitable for mapping problems with analog target values, it is useful for analog data discrimination problems.

  • On a Numerical Solution for the Near-Field of Microstrip Antennas

    Yasufumi SASAKI  Masanobu KOMINAMI  Shinnosuke SAWA  

     
    LETTER

      Vol:
    E76-B No:7
      Page(s):
    759-761

    Numerical solutions for the near-field of microstrip antennas are presented. The field distribution is calculated by taking the inverse Fourier transform involving the current distribution with the help of the spectral-domain moment method. A new technique to save the computation time is devised, and the field pattern of the circularly polarized antenna is illustrated.

  • An Estimation of Pressure and Flow in a Three-Dimensional Dynamic Model of the Larynx with Nonuniform Glottis by FVM

    Chengxiang LU  Takayoshi NAKAI  Hisayoshi SUZUKI  

     
    PAPER-Modeling and Simulation

      Vol:
    E76-A No:7
      Page(s):
    1252-1262

    In order to describe the flow passing through the glottis, we constructed a dynamic three-dimensional finite element model of the human larynx. The transient flow fields in the laryngeal model were calculated to examine the dynamic effects generated by the vocal fold vibration. A phase difference between the upper and lower edges of the vocal folds was included in the model to investigate the effect of the glottal shapes on pressure-flow relationships in the larynx during the vocal fold vibration. Using STAR-CD thermofluids analysis system, which is capable of treating the transient flow in moving-boundary situations with finite volume method, we solved the viscous incompressible Navier-Stokes equations to investigate the glottal flows and transglottal pressures as a function of the vocal fold vibration. The results were compared to the uniform glottis model and the theoretical model proposed by Ishizaka and Matsudaira, respectively. The effects of dynamic factors on the pressure distributions and flow patterns in the larynx resulting from the vocal-fold vibration were also discussed.

  • A Differential-Geometrical Theory of Sensory System --Relations between the Psychophysical, the DL and the JND Functions

    Ryuzo TAKIYAMA  

     
    PAPER-Mathematical Theory

      Vol:
    E76-A No:5
      Page(s):
    683-688

    This paper discusses psychophysical aspects of human sensory system through a differential-geometrical formulation. The discussions reveal relationships among three fundamental functions--the psychophysical, the DL and the JND functions, which characterize sensory system.

  • Process and Device Technologies of CMOS Devices for Low-Voltage Operation

    Masakazu KAKUMU  

     
    INVITED PAPER

      Vol:
    E76-C No:5
      Page(s):
    672-680

    Process and device technologies of CMOS devices for low-voltage operation are described. First, optimum power-supply voltage for CMOS devices is examined in detail from the viewpoints of circuit performance, device reliability and power dissipation. As a result, it is confirmed that power-supply voltage can be reduced without any speed loss of the CMOS device. Based upon theoretical understanding, the author suggests that lowering threshold voltage and reduction of junction capacitance are indispensable for CMOS devices with low-voltage supply, in order to improve the circuit performance, as expected from MOS device scaling. Process and device technologies such as Silicon On Insulator (SOI) device, low-temperature operation and CMOS Shallow Junction Well FET (CMOS-SJET) structure are reviewed for reduction of the threshold voltage and junction capacitance which lead to high-seed operation of the COMS device at low-voltage.

  • A 10-b 300-MHz Interpolated-Parallel A/D Converter

    Hiroshi KIMURA  Akira MATSUZAWA  Takashi NAKAMURA  Shigeki SAWADA  

     
    PAPER

      Vol:
    E76-C No:5
      Page(s):
    778-786

    This paper describes a monolithic 10-b A/D converter that realized a maximum conversion frequency of 300 MHz. Through the development of the interpolated-parallel scheme, the severe requirement for the transistor Vbe matching can be alleviated drastically, which improves differential nonlinearity (DNL) significantly to within 0.4 LSB. Furthermore, an extremely small input capacitance of 8 pF can be attained, which translates into better dynamic performance such as SNR of 56 dB and THD of 59 dB for an input frequency of 10 MHz. Additionally, the folded differential logic circuit has been developed to reduce the number of elements, power dissipation, and die area drastically. Consequently, the A/D converter has been implemented as a 9.0 4.2-mm2 chip integrating 36K elements, which consumes 4.0 W using a 1.0-µm-rule, 25-GHz ft, double-polysilicon self-aligned bipolar technology.

  • Safety Control of Power Press by Using Fail-Safe Multiple-Valued Logic

    Masayoshi SAKAI  Masakazu KATO  Koichi FUTSUHARA  Masao MUKAIDONO  

     
    PAPER-Fail-Safe/Fault Tolerant

      Vol:
    E76-D No:5
      Page(s):
    577-585

    This paper first clarifies the logic construction of safety control for the operation of a power press and then describes fail-safe dual two-rail system signal processing and fail-safe multiple-valued logic operations as methods for achieving this control as a fail-safe system. It finally shows a circuit for generating fail-safe two-rail run button signals based on ternary logic for concrete operation of the power press and an operation control circuit for confirming brake performance for each cycle of slide operation by using the run button signals. The control circuit uses such multiple-valued logic operations that binary logic signals that do not erroneously go logic 1 are added to a multiple-valued logic signal and the multiple-valued logic signal is converted to a binary logic signal that does not erroneously go logic 1 by a threshold operation.

  • Synthesis of Discrete-Time Cellular Neural Networks for Binary Image Processing

    Chun-Ying HO  Dao-Heng Yu  Shinsaku MORI  

     
    PAPER-Neural Nets--Theory and Applications--

      Vol:
    E76-A No:5
      Page(s):
    735-741

    In this paper, a synthesizing method is proposed for the design of discrete-time cellular neural networks for binary image processing. Based on the theory of digital-logical design paradigm of threshold logic, the template parameters of the discrete-time cellular neural network for a prescribed binary image processing problem are calculated. Application examples including edge detection, connected component detection, and hole filling are given to demonstrate the merits and limitations of the proposed method. For a given realization of the parameters of the cloning template, a guideline for the selection of the offset Ic for maximum error tolerance is also considered.

  • Analysis of MRI Slotted Tube Resonator Having a Shield of Conducting Circular Cylinder

    Qiang CHEN  Kunio SAWAYA  Saburo ADACHI  Hisaaki OCHI  Etsuji YAMAMOTO  

     
    PAPER-Antennas and Propagation

      Vol:
    E76-B No:5
      Page(s):
    553-560

    A slotted tube resonator (STR) having a shield of conducting circular cylinder which is used as a probe for the magnetic resonance imaging (MRI) is analyzed by using the variational method and the dyadic Green's function of a circular waveguide. Three surface current modes are employed to expand the currents on the STR. Quadruple integrals appearing in the variational expression are evaluated analytically for saving the CPU time. Resonant frequency, Q value and the magnitude of magnetic field distributions for various radii of the shields are obtained to show the effects of the shield. Some measured date are compared with the theoretical results to confirm the validity of the present analysis.

1821-1840hit(1872hit)