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16561-16580hit(16991hit)

  • Time Series Analysis Based on Exponential Model Excited by t-Distribution Process and Its Algorithm

    Junibakti SANUBARI  Keiichi TOKUDA  Mahoki ONODA  

     
    PAPER-Digital Signal Processing

      Vol:
    E76-A No:5
      Page(s):
    808-819

    In this paper, a new time series analysis method is proposed. The proposed method uses the exponential (EXP) model. The residual signal is assumed to be identically and independently distributed (IID). To achieve accurate and efficient estimates, the parameter of the system model is calculated by maximizing the logarithm of the likelihood of the residual signal which is assumed to be IID t-distribution. The EXP model theoretically assures the stability of the system. This model is appropriate for analyzing signals which have not only poles, but also poles and zeroes. The asymptotic efficiency of the EXP model is addressed. The optimal solution is calculated by the Newton-Raphson iteration method. Simulation results show that only a small number of iterations are necessary to reach stationary points which are always local minimum points. When the method is used to estimate the spectrum of synthetic signals, by using small α we can achieve a more accurate and efficient estimate than that with large α. To reduce the calculation burden an alternative algorithm is also proposed. In this algorithm, the estimated parameter is updated in every sampling instant using an imperfect, short-term, gradient method which is similar to the LMS algorithm.

  • Fundametal Properties of Multiple-Valued Logic Functions Monotonic with Respect to Ambiguity

    Kyoichi NAKASHIMA  Noboru TAKAGI  

     
    PAPER-Logic and Logic Functions

      Vol:
    E76-D No:5
      Page(s):
    540-547

    The paper considers multiple-valued logic systems having the property that the ambiguity of the system increases as the ambiguity of each component increases. The partial-ordering relation with respect to ambiguity with the greatest element 1/2 and minimal elements 0, 1 or simply the ambiguity relation is introduced in the set of truth values V {0, 1/ (p1), , 1/2, , (p2) / (p1), 1}. A-monotonic p-valued logic functions are defined as p-valued logic functions monotonic with respect to the ambiguity relation. A necessary and sufficient condition for A-monotonic p-valued logic functions is presented along with the proofs, and their logic formulae using unary operators defined in the ambiguity relation are given. Some discussions on the extension of theories to other partial-ordering relations are also given.

  • An Implementation of Multiple-Valued Logic and Fuzzy Logic Circuits Using 1.5 V Bi-CMOS Current-Mode Circuit

    Mamoru SASAKI  Kazutaka TANIGUCHI  Yutaka OGATA  Fumio UENO  Takahiro INOUE  

     
    PAPER-Circuits

      Vol:
    E76-D No:5
      Page(s):
    571-576

    This paper presents Bi-CMOS current-mode multiple valued logic circuit with 1.5 V supply voltage. This circuit is composed of current mirror, threshold detector and current source. This circuit has advantages such as high accuracy, high speed, high density and low supply voltage. So, it is possible to realize high-radix multiple valued logic circuit. As an other application of the proposed circuit, a processing unit of fuzzy inference is given. This circuit operates with high speed and high accuracy. The circuit simulation of the proposed circuit has been performed using SPICE2 program.

  • Code Assignment Algorithm for Highly Parallel Multiple-Valued Combinational Circuits Based on Partition Theory

    Saneaki TAMAKI  Michitaka KAMEYAMA  Tatsuo HIGUCHI  

     
    PAPER-Logic Design

      Vol:
    E76-D No:5
      Page(s):
    548-554

    Design of locally computable combinational circuits is a very important subject to implement high-speed compact arithmetic and logic circuits in VLSI systems. This paper describes a multiple-valued code assignment algorithm for the locally computable combinational circuits, when a functional specification for a unary operation is given by the mapping relationship between input and output symbols. Partition theory usually used in the design of sequential circuits is effectively employed for the fast search for the code assignment problem. Based on the partition theory, mathematical foundation is derived for the locally computable circuit design. Moreover, for permutation operations, we propose an efficient code assignment algorithm based on closed chain sets to reduce the number of combinations in search procedure. Some examples are shown to demonstrate the usefulness of the algorithm.

  • Output Permutation and the Maximum Number of Implicants Needed to Cover the Multiple-Valued Logic Functions

    Yutaka HATA  Kazuharu YAMATO  

     
    PAPER-Logic Design

      Vol:
    E76-D No:5
      Page(s):
    555-561

    An idea of optimal output permutation of multiple-valued sum-of-products expressions is presented. The sum-of-products involve the TSUM operator on the MIN of window literal functions. Some bounds on the maximum number of implicants needed to cover an output permuted function are clarified. One-variable output permuted functions require at most p1 implicants in their minimal sum-of-products expressions, where p is the radix. Two-variable functions with radix between three and six are analyzed. Some speculations of maximum number of the implicants could be established for functions with higher radix and more than 2-variables. The result of computer simulation shows that we can have a saving of approximately 15% on the average using permuting output values. Moreover, we demonstrate the output permutation based on the output density as a simpler method. For the permutation, some speculation is shown and the computer simulation shows a saving of approximately 10% on the average.

  • 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.

  • Intermittency of Recurrent Neuron and Its Network Dynamics

    Toshihide TSUBATA  Hiroaki KAWABATA  Yoshiaki SHIRAO  Masaya HIRATA  Toshikuni NAGAHARA  Yoshio INAGAKI  

     
    PAPER-Chaos and Related Topics

      Vol:
    E76-A No:5
      Page(s):
    695-703

    Various models of a neuron have been proposed and many studies about them and their networks have been reported. Among these neurons, this paper describes a study about the model of a neuron providing its own feedback input and possesing a chaotic dynamics. Using a return map or a histogram of laminar length, type-I intermittency is recognized in a recurrent neuron and its network. A posibility of controlling dynamics in recurrent neural networks is also mentioned a little in this paper.

  • Design Considerations for Low-Voltage Crystal Oscillator Circuit in a 1.8-V Single Chip Microprocessor

    Shigeo KUBOKI  Takehiro OHTA  Junichi KONO  Yoji NISHIO  

     
    PAPER

      Vol:
    E76-C No:5
      Page(s):
    701-707

    A low-voltage, high-speed 4-bit CMOS single chip microprocessor, with instruction execution time of 1.0µs at a power supply voltage of 1.8V, has been developed. A single chip processor generally includes crystal oscillation circuits to generate a system clock or a time-base clock. But when the operating voltage is lowered, it becomes difficult to get oscillations to start reliably and to continue stably. This paper describes a low voltage circuit design method for built-in crystal oscillators. Simple design equations for oscillation starting voltage and oscillation starting time are introduced. Then effects of the circuit device parameters, such as power supply voltage, loop gain values, and subthreshold swing S, on the low voltage performance of the crystal oscillators are considered. It is shown that the crystal oscillators operate in a tailing (subthreshold) region at voltages lower than about 1.8 V. Subthreshold swing, threshold voltage, and open loop gain have a significant influence on low voltage oscillation capability. This design method can be applied to crystal oscillators for a wide range of operating voltages.

  • 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.

  • Minimum Covering Run Expression of Document Images Based on Matching of Bipartite Graph

    Supoj CHINVEERAPHAN  Ken'ichi DOUNIWA  Makoto SATO  

     
    PAPER

      Vol:
    E76-D No:4
      Page(s):
    462-469

    An efficient technique for expressing document image is required as part of a unified approach to document image processing. This paper presents a new method, Minimum Covering Run (MCR), for expressing binary images. The name being adapted from horizontal or vertical run representation. The proposed technique uses some horizontal and vertical runs together to represent binary images in which the total number of representative runs is minimized. Considering the characteristic of above run types precisely, it is shown that horizontal and vertical runs of any binary image could be thought of as partite sets of a bipartite graph. Consequently, the MCR expression that corresponds to the construction of one of the most interesting problems in graphs; i.e., maximum matching, is analogously found by using an algorithm which solves this problem in a corresponding graph. The most efficient algorithm takes at most O(n5/2) computations for solving the problem where n is the sum of cardinalities of both partite sets. However, some patterns in images like tables or line drowings, generally, have a large number of runs representing them which results in a long processing time. Therefore, we provide the Rectangular Segment Analysis (RSA) as a pre-processing to define runs representing such patterns beforehand. We also show that horizontal and vertical covering parts of the proposed expression are able to represent stroke components of characters in document images. As an implementation, an efficient algorithm including arrangement for run data structure of the MCR expression is presented. The experimental results show the possibility of stroke extraction of characters in document images. As an application, some patterns such as tables can be extracted from document images.

  • Minimizing the Edge Effect in a DRAM Cell Capacitor by Using a Structure with High-Permittivity Thin Film

    Takeo YAMASHITA  Tadahiro OHMI  

     
    PAPER-Device Technology

      Vol:
    E76-C No:4
      Page(s):
    556-561

    The concentration of the electric field at the edge of the electrode has been simulated in several types of flat DRAM cell capacitors with high permittivity dielectrics. The results indicated that the permittivity of the material surrounding the edge of the electrode as well as the geometrical structure affected the concentration of the electric field. The electric field strength was minimized and most evenly distributed by utilizing the structure in which the sidewall of the capacitor dielectric was terminated at the edge of the electrode by a low-dielectric constant insulator. High-precision fabrication of the capacitor's profile is required for the minimization and uniformity of the electric field.

  • Image Region Correspondence by Color and Structural Similarity

    Yi-Long CHEN  Hiromasa NAKATANI  

     
    PAPER

      Vol:
    E76-D No:4
      Page(s):
    429-436

    Correspondence based on regions rather than lines seems to be effective, as regions are usually fewer than other image features and provide global information such as size, color, adjacency, etc. In this paper, we present a region matching approach for solving the correspondence problem. Images are segmented into regions and are individually described by classification tables using region adjacencies. From the structural description of the two images, the region matching process based on color and structural similarity is carried out. First, a small number of significant regions are selected and matched by using color, and then they are used as handles for constraint propagation to match the remaining regions by using structures. Our technique was implemented by using an efficient selection and propagation algorithm and was tested with a variety of scenes.

  • Precise Linewidth Measurement Using a Scanning Electron Probe

    Fumio MIZUNO  Satoru YAMADA  Akihiro MIURA  Kenji TAKAMOTO  Tadashi OHTAKA  

     
    PAPER-Process Technology

      Vol:
    E76-C No:4
      Page(s):
    600-606

    Practical linewidth measurement accuracy better than 0.02 µm 3 sigma that meets the production requirement for devices with sub-half micron features, was achieved in a field emission scanning electron-beam metrology system (Hitachi S-7000). In order to establish high accuracy linewidth measurement, it was found in the study that reduction of electron-beam diameter and precise control of operating conditions are significantly effective. For the purpose of reducing electron-beam diameter, a novel electron optical system was adopted to minimize the chromatic aberration which defines electron-beam profile. As a result the electron beam diameter was reduced from 20 nm to 16 nm. In order to reduce measurement uncertainties associated with actual operating conditions, a field emission electron gun geometry and an objective lens current monitor were investigated. Then the measurement uncertainties due to operating conditions was reduced from 0.016 µm to 0.004 µm.

  • A Waveform Relaxation Method Applicable to the Simulation of ECL Circuits with Gate Level Partitioning

    Vijaya Gopal BANDI  Hideki ASAI  

     
    LETTER-Neural Networks

      Vol:
    E76-A No:4
      Page(s):
    657-660

    This paper describes a novel but simple method of implementing waveform relaxation technique for bipolar circuits involving ECL gates. This method performs gate level partitioning of ECL circuits not only during the cutoff state of the input transistor but also when the input transistor is in its active state. Partitioning at all times has become possible due to the favorable property of input and output stages of ECL gates. It is shown that this method is faster than direct method even when the circuits containing only few gates is simulated. Further, it is shown that the present method is applicable to the case where the interconnections between the ECL gates is treated as lossy transmission lines.

  • Relaxation-Based Circuit Simulation Techniques in the Frequency Domain

    Hiroaki MAKINO  Hideki ASAI  

     
    PAPER-Modeling and Simulation

      Vol:
    E76-A No:4
      Page(s):
    626-630

    This paper describes the novel relaxation-based algorithm for the harmonic analysis of nonlinear circuits. First, we present Iterated Spectrum Analysis based on harmonic balance method, where the harmonic balance method is applied to every node independently. As a result, we can avoid dealing with large scale Jacobian matrices and reduce the total simulation time, compared with the conventional method based on Galerkin's procedure or the harmonic balance method. Next, we define the frequency domain latency. Furthermore, we refer to the possibility for exploitation of three types of latency, i.e., relaxation iteration latency, frequency domain latency and Newton iteration latency. And we propose the multirate-sampling technique based on the consideration of the frequency domain latency. Finally, we apply the present technique to the simple analog circuit simulation and verify its availability for the harmonic analysis.

  • Simple Quotient-Digit-Selection Radix-4 Divider with Scaling Operation

    Motonobu TONOMURA  

     
    PAPER

      Vol:
    E76-A No:4
      Page(s):
    593-602

    This paper deals with the theory and design method of an efficient radix-4 divider using carry-propagation-free adders based on redundant binary {-1,0,+1} representation. The usual method of normalizing the divisor in the range [1/2,1) eliminates the advantages of using a higher radix than two, bacause many digits of the partial remainder are required to select the quotient digits. In the radix-4 case, it is shown that it is possible to select the quotient digits to refer to only the four (in the usual normalizing method it is seven) most significant digits of the partial remainder, by scaling the divisor in the range [12/8,13/8). This leads to radix-4 dividers more effective than radix-2 ones. We use the hyperstring graph representation proposed in Ref.(18) for redundant binary adders.

  • A Linear Phase Two-Channel Filter Bank Allowing Perfect Reconstruction

    Hitoshi KIYA  Mitsuo YAE  Masahiro IWAHASHI  

     
    PAPER-Linear and Nonlinear Digital Filters

      Vol:
    E76-A No:4
      Page(s):
    620-625

    We propose a design method for a two-channel perfect reconstruction FIR filter banks employing linear-phase filters. This type of filter bank is especially important in splitting image signals into frequency bands for subband image cording. Because in such an application, it is necessary to use the combination of linear-phase filters and symmetric image signal, namely linear phase signal to avoid the increase in image size caused by filtering. In this paper, first we summarize the design conditions for two-channel filter banks. Next, we show that the design problem is reduced to a very simple linear equation, by using a half-band filter as a lowpass filter. Also the proposed method is available to lead filters with fewer complexity, which enable us to use simple arithmetic operations. For subband coding, the property is important because it reduces hardware complexity.

  • On the Specification for VLSI Systolic Arrays

    Fuyau LIN  

     
    PAPER

      Vol:
    E76-A No:4
      Page(s):
    496-506

    Formal verification has become an increasing prominent technique towards establishing the correctness of hardware designs. We present a framework to specifying and verifying the design of systolic architectures. Our approach allows users to represent systolic arrays in Z specification language and to justify the design semi-automatically using the verifier. Z is a notation based on typed set theory and enriched by a schema calculus. We describe how a systolic array for matrix-vector multiplication can be specified and justified with respect to its algorithm.

  • Computing k-Edge-Connected Components of a Multigraph

    Hiroshi NAGAMOCHI  Toshimasa WATANABE  

     
    PAPER

      Vol:
    E76-A No:4
      Page(s):
    513-517

    In this paper, we propose an algorithm of O(|V|min{k,|V|,|A|}|A|) time complexity for finding all k-edge-connected components of a given digraph D=(V,A) and a positive integer k. When D is symmetric, incorporating a preprocessing reduces this time complexity to O(|A|+|V|2+|V|min{k,|V|}min{k|V|,|A|}), which is at most O(|A|+k2|V|2).

  • Surface Reconstruction Model for Realistic Visualization

    Hiromi T. TANAKA  Fumio KISHINO  

     
    PAPER

      Vol:
    E76-D No:4
      Page(s):
    494-500

    Surface reconstruction and visualization from sparse and incomplete surface data is a fundamental problem and has received growing attention in both computer vision and graphics. This paper presents a computational scheme for realistic visualization of free-formed surfaces from 3D range images. The novelty of this scheme is that by integrating computer vision and computer graphics techniques, we dynamically construct a mesh representation of the arbitrary view of the surfaces, from a view-invariant shape description obtained from 3D range images. We outline the principle of this scheme and describle the frame work of a graphical reconstruction model, we call arbitrarily oriented meshes', which is developed based on differential geometry. The experimental results on real range data of human faces are shown.

16561-16580hit(16991hit)