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[Author] Manabu KOBAYASHI(11hit)

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  • Reconfigurable Circuit Design Based on Arithmetic Logic Unit Using Double-Gate CNTFETs

    Hiroshi NINOMIYA  Manabu KOBAYASHI  Yasuyuki MIURA  Shigeyoshi WATANABE  

     
    LETTER-VLSI Design Technology and CAD

      Vol:
    E97-A No:2
      Page(s):
    675-678

    This letter describes a design methodology for an arithmetic logic unit (ALU) incorporating reconfigurability based on double-gate carbon nanotube field-effect transistors (DG-CNTFETs). The design of a DG-CNTFET with an ambipolar-property-based reconfigurable static logic circuit is simple and straightforward using an ambipolar binary decision diagram (Am-BDD), which represents the cornerstone for the automatic pass transistor logic (PTL) synthesis flows of ambipolar devices. In this work, an ALU with 16 functions is synthesized by the design methodology of a DG-CNTFET-based reconfigurable static logic circuit. Furthermore, it is shown that the proposed ALU is much more flexible and practical than a conventional DG-CNTFET-based reconfigurable ALU.

  • Reconfigurable Dynamic Logic Circuit Generating t-Term Boolean Functions Based on Double-Gate CNTFETs

    Manabu KOBAYASHI  Hiroshi NINOMIYA  Yasuyuki MIURA  Shigeyoshi WATANABE  

     
    PAPER-Circuit Theory

      Vol:
    E97-A No:5
      Page(s):
    1051-1058

    Hassoune and O'Connor proposed a dynamically reconfigurable dynamic logic circuit (DRDLC) that generates Boolean functions by using double-gate (DG) carbon nanotube (CNT) FETs, which have an ambipolar property. O'Connor et al. proposed a DRDLC that generates 14 Boolean functions asing two Boolean inputs with seven transistors. Furthermore, DRDLCs that generates all 16 Boolean functions have been proposed. In this paper, we focus on the design of a dynamic logic circuit with n Boolean inputs. First, we show a DRDLC that generates the monomial Boolean functions. Next, we propose a DRDLC that generates the whole set of Boolean functions consisting of t terms or less. Finally, we report the number of Boolean functions generated by the proposed DRDLC.

  • Complexity Reduction of the Gazelle and Snyders Decoding Algorithm for Maximum Likelihood Decoding

    Hideki YAGI  Manabu KOBAYASHI  Shigeichi HIRASAWA  

     
    PAPER-Coding Theory

      Vol:
    E86-A No:10
      Page(s):
    2461-2472

    Several reliability based code search algorithms for maximum likelihood decoding have been proposed. These algorithms search the most likely codeword, using the most reliable information set where the leftmost k (the dimension of code) columns of generator matrix are the most reliable and linearly independent. Especially, D. Gazelle and J. Snyders have proposed an efficient decoding algorithm and this algorithm requires small number of candidate codewords to find out the most likely codeword. In this paper, we propose new efficient methods for both generating candidate codewords and computing metrics of candidate codewords to obtain the most likely codeword at the decoder. The candidate codewords constructed by the proposed method are identical those in the decoding algorithm of Gazelle et al. Consequently, the proposed decoding algorithm reduces the time complexity in total, compared to the decoding algorithm of Gazelle et al. without the degradation in error performance.

  • An Efficient Heuristic Search Method for Maximum Likelihood Decoding of Linear Block Codes Using Dual Codes

    Tomotsugu OKADA  Manabu KOBAYASHI  Shigeichi HIRASAWA  

     
    PAPER-Coding Theory

      Vol:
    E85-A No:2
      Page(s):
    485-489

    Y. S. Han et al. have proposed an efficient maximum likelihood decoding (MLD) algorithm using A* algorithm which is the graph search method. In this paper, we propose a new MLD algorithm for linear block codes. The MLD algorithm proposed in this paper improves that given by Han et al. utilizing codewords of dual codes. This scheme reduces the number of generated codewords in the MLD algorithm. We show that the complexity of the proposed decoding algorithm is reduced compared to that given by Han et al. without increasing the probability of decoding error.

  • Adaptive Decoding Algorithms for Low-Density Parity-Check Codes over the Binary Erasure Channel

    Gou HOSOYA  Hideki YAGI  Manabu KOBAYASHI  Shigeichi HIRASAWA  

     
    PAPER-Coding Theory

      Vol:
    E92-A No:10
      Page(s):
    2418-2430

    Two decoding procedures combined with a belief-propagation (BP) decoding algorithm for low-density parity-check codes over the binary erasure channel are presented. These algorithms continue a decoding procedure after the BP decoding algorithm terminates. We derive a condition that our decoding algorithms can correct an erased bit which is uncorrectable by the BP decoding algorithm. We show by simulation results that the performance of our decoding algorithms is enhanced compared with that of the BP decoding algorithm with little increase of the decoding complexity.

  • An Improved Method of Reliability-Based Maximum Likelihood Decoding Algorithms Using an Order Relation among Binary Vectors

    Hideki YAGI  Manabu KOBAYASHI  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    PAPER-Coding Theory

      Vol:
    E87-A No:10
      Page(s):
    2493-2502

    Reliability-based maximum likelihood decoding (MLD) algorithms of linear block codes have been widely studied. These algorithms efficiently search the most likely codeword using the generator matrix whose most reliable and linearly independent k (dimension of the code) columns form the identity matrix. In this paper, conditions for omitting unnecessary metrics computation of candidate codewords are derived in reliability-based MLD algorithms. The proposed conditions utilize an order relation of binary vectors. A simple method for testing if the proposed conditions are satisfied is devised. The method for testing proposed conditions requires no real number operations and, consequently, the MLD algorithm employing this method reduces the number of real number operations, compared to known reliability-based MLD algorithms.

  • Density Evolution Analysis of Robustness for LDPC Codes over the Gilbert-Elliott Channel

    Manabu KOBAYASHI  Hideki YAGI  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    PAPER-Coding Theory

      Vol:
    E91-A No:10
      Page(s):
    2754-2764

    In this paper, we analyze the robustness for low-density parity-check (LDPC) codes over the Gilbert-Elliott (GE) channel. For this purpose we propose a density evolution method for the case where LDPC decoder uses the mismatched parameters for the GE channel. Using this method, we derive the region of tuples of true parameters and mismatched decoding parameters for the GE channel, where the decoding error probability approaches asymptotically to zero.

  • Circuit Design of Reconfigurable Logic Based on Double-Gate CNTFETs

    Manabu KOBAYASHI  Hiroshi NINOMIYA  Shigeyoshi WATANABE  

     
    LETTER-Circuit Theory

      Vol:
    E96-A No:7
      Page(s):
    1642-1644

    I. O'Connor et al. have proposed a dynamically reconfigurable dynamic logic circuit (DRDLC) to generate some logic functions by using the double-gate (DG) carbon nanotube (CNT) FETs which have the ambipolar property [1]. This DRDLC consists of seven transistors to generate 14 logic functions which do not include the XOR and XNOR functions. On the other hand, K. Jabeur et al. have proposed a DRDLC to generate the whole set of 16 logic functions including XOR and XNOR by adding 4 or 8 transistors to O'Connor's circuit [5]. In this letter, we propose a DRDLC, which consists of only seven transistors, to generate the whole set of 16 logic functions by using DG-CNTFETs. Finally, we show that the number of transistors can be reduced compared to the conventional DRDLC to generate 16 logic functions.

  • Probabilistic Fault Diagnosis and its Analysis in Multicomputer Systems

    Manabu KOBAYASHI  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    PAPER-Coding theory and techniques

      Vol:
    E101-A No:12
      Page(s):
    2072-2081

    F.P. Preparata et al. have proposed a fault diagnosis model to find all faulty units in the multicomputer system by using outcomes which each unit tests some other units. In this paper, for probabilistic diagnosis models, we show an efficient diagnosis algorithm to obtain a posteriori probability that each of units is faulty given the test outcomes. Furthermore, we propose a method to analyze the diagnostic error probability of this algorithm.

  • Reduced Reconfigurable Logic Circuit Design Based on Double Gate CNTFETs Using Ambipolar Binary Decision Diagram

    Hiroshi NINOMIYA  Manabu KOBAYASHI  Shigeyoshi WATANABE  

     
    LETTER-Circuit Theory

      Vol:
    E96-A No:1
      Page(s):
    356-359

    This letter describes the design methodology for reduced reconfigurable logic circuits based on double gate carbon nanotube field effect transistors (DG-CNTFETs) with ambipolar propoerty. Ambipolar Binary Decision Diagram (Am-BDD) which represents the cornerstone for automatic pass transistor logic (PTL) synthesis flows of ambipolar devices was utilized to build DG-CNTFET based n-input reconfigurable cells in the conventional approach. The proposed method can reduce the number of ambipolar devices for 2-inputs reconfigurable cells, incorporating the simple Boolean algebra in the Am-BDD compared with the conventional approach. As a result, the static 2-inputs reconfigurable circuit with 16 logic functions can be synthesized by using 8 DG-CNTFETs although the previous design method needed 12 DG-CNTFETs for the same purpose.

  • Asymptotic Evaluation of Classification in the Presence of Label Noise

    Goki YASUDA  Tota SUKO  Manabu KOBAYASHI  Toshiyasu MATSUSHIMA  

     
    PAPER-Learning

      Pubricized:
    2022/08/26
      Vol:
    E106-A No:3
      Page(s):
    422-430

    In a practical classification problem, there are cases where incorrect labels are included in training data due to label noise. We introduce a classification method in the presence of label noise that idealizes a classification method based on the expectation-maximization (EM) algorithm, and evaluate its performance theoretically. Its performance is asymptotically evaluated by assessing the risk function defined as the Kullback-Leibler divergence between predictive distribution and true distribution. The result of this performance evaluation enables a theoretical evaluation of the most successful performance that the EM-based classification method may achieve.