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23641-23660hit(30728hit)

  • Spectroscopic MR Imaging Using the Spread Spectrum Produced by Oscillating Gradient Fields

    Kunio TAKAYA  

     
    PAPER-Image

      Vol:
    E84-A No:3
      Page(s):
    875-883

    A chemical shift MR method which utilizes a oscillating gradient field is presented in this paper. Frequency modulation resulting from oscillating a gradient field spreads the spectrum that contains both chemical shift and spatial information, over a wide frequency range by using a large modulation factor in FM. The chemical shift spectrum resides within every frequency band segmented by the modulation frequency ωm. The spectral elements gathered from all such frequency segments for a chemical shift frequency contain the spatial image of that particular chemical shift frequency, despite the distortion introduced by a series of the Bessel functions acting as a point spread function. A sum of several Bessel functions of the first kind Jn(. ) is used to approximate the deconvolution process, since the sum staggered with respect to n has a desirable peaking property useful in deconvolution. This leads to devise a new image reconstruction algorithm based on the simple moving average over the spatial coordinate for which the oscillating gradient is applied. Furthermore, the number of echo measurements necessary for an image size of N N is reduced from N2 of the spin echo chemical shift imaging down to N by this method. Simulation results supporting the validity of this method are also presented in this paper.

  • Proposal of a Multi-Threaded Processor Architecture for Embedded Systems and Its Evaluation

    Shinsuke KOBAYASHI  Yoshinori TAKEUCHI  Akira KITAJIMA  Masaharu IMAI  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    748-754

    In this paper, an architecture of multi-threaded processor for embedded systems is proposed and evaluated comparing with other processors for embedded systems. The experimental results show the trade-off of hardware costs and execution times among processors. Taking proposed multi-threaded processor into account as an embedded processor, design space of embedded systems are enlarged and more suitable architecture can be selected under some design constraints.

  • An Autonomous Distributed Scheduling Scheme for Parallel Machine Problems

    Morikazu NAKAMURA  Norifumi NAKADA  Hideki KINJO  Kenji ONAGA  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    763-770

    Autonomous distributed scheduling is based on the autonomous decentralized optimization and recently focused as one of flexible scheduling techniques which can more cope with dynamically changing situation than traditional ones. This paper proposes an autonomous distributed scheduling scheme for the parallel machine scheduling problem. Through computer simulation, we observe that our proposed scheme can more quickly reduce the total deadline over-time than one in the literature and can adapt flexibly to unusual situation (addition of jobs).

  • A Hierarchical Statistical Optimization Method Driven by Constraint Generation Based on Mahalanobis' Distance

    Tomohiro FUJITA  Hidetoshi ONODERA  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    727-734

    This paper presents a method of statistical system optimization. The method uses a constraint generation, which is a design methodology based on a hierarchical top-down design, to give specifications to sub-circuits of the system. The specifications are generated not only to reduce the costs of sub-circuits but also to take adequate margin to achieve enough yield of the system. In order to create an appropriate amount of margin, a term which expresses a statistical figure based on Mahalanobis' distance is added to the constraint generation problem. The method is applied to a PLL, and it is confirmed that the yield of the lock-up time reaches 100% after the optimization.

  • A Heuristic Algorithm FMDB for the Minimum Initial Marking Problem of Petri Nets

    Shin'ichiro NISHI  Satoshi TAOKA  Toshimasa WATANABE  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    771-780

    This paper proposes a new heuristic algorithm FMDB for the minimum initial marking problem MIM of Petri nets: "Given a Petri net and a firing count vector X, find an initial marking M0, with the minimum total token number, for which there is a sequence δ of transitions such that each transition t appears exactly X(t) times in δ, the first transition is firable on M0 and the rest can be fired one by one subsequently. " Experimental results show that FMDB produces better solutions than any known algorithm.

  • Graph Augmentation Problems with Degree-Unchangeable Vertices

    Toshiya MASHIMA  Toshimasa WATANABE  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    781-793

    The k-vertex-connectivity augmentation problem for a specified set of vertices of a graph with degree-unchangeable vertices, kVCA(G,S,D), is defined as follows: "Given a positive integer k, an undirected graph G=(V,E), a specified set of vertices S V and a set of degree-changeable vertices D V, find a smallest set of edges E such that the vertex-connectivity of S in (V,E E) is at least k and E {(u,v) u,v D}. " The main result of the paper is that checking the existence of a solution and finding a solution to 2VCA(G,S,D) or 3VCA(G,S,D) can be done in O(|V|+|E|) or O(|V|(|V|+|E|)) time, respectively.

  • Equalisation of Time Variant Multipath Channels Using Amplitude Banded LMS Algorithms

    Tetsuya SHIMAMURA  Colin F. N. COWAN  

     
    PAPER-Digital Signal Processing

      Vol:
    E84-A No:3
      Page(s):
    802-812

    For the purpose of equalisation of rapidly time variant multipath channels, we derive a novel adaptive algorithm, the amplitude banded LMS (ABLMS), which implements a non-linear adaptation based on a coefficient matrix. Then we develop the ABLMS algorithm as the adaptation procedure for a linear transversal equaliser (LTE) and a decision feedback equaliser (DFE) where a parallel adaptation scheme is deployed. Computer simulations demonstrate that with a small increase of computational complexity, the ABLMS based parallel equalisers provide a significant improvement related to the conventional LMS DFE and the LMS LTE in the case of a second order Markov communication channel model.

  • Backpropagation Algorithm for LOGic Oriented Neural Networks with Quantized Weights and Multilevel Threshold Neurons

    Takeshi KAMIO  Hisato FUJISAKA  Mititada MORISUE  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    705-712

    Multilayer feedforward neural network (MFNN) trained by the backpropagation (BP) algorithm is one of the most significant models in artificial neural networks. MFNNs have been used in many areas of signal and image processing due to high applicability. Although they have been implemented as analog, mixed analog-digital and fully digital VLSI circuits, it is still difficult to realize their hardware implementation with the BP learning function efficiently. This paper describes a special BP algorithm for the logic oriented neural network (LOGO-NN) which we have proposed as a sort of MFNN with quantized weights and multilevel threshold neurons. Both weights and neuron outputs are quantized to integer values in LOGO-NNs. Furthermore, the proposed BP algorithm can reduce high precise calculations. Therefore, it is expected that LOGO-NNs with BP learning can be more effectively implemented as digital type circuits than the common MFNNs with the classical BP. Finally, it is shown by simulations that the proposed BP algorithm for LOGO-NNs has good performance in terms of the convergence rate, convergence speed and generalization capability.

  • An Efficient Reduction Method of a Substrate RC Network Model

    Tomohisa KIMURA  Makiko OKUMURA  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    698-704

    This paper proposes an efficient reduction method for a substrate network model, which is extracted from layout data, to analize a substrate coupling noise. The proposed method adopts in a reduction operation a hierarchic structure of a substrate RC network model, a computational procedure using matrix elements, and an expression of admittance as polynominal in complex frequency s=jω. These techniques improve computational efficiency and are suitable for an implementation. In the example of a triple well CMOS circuit, a reduced model, from 7500 nodes to 5 nodes, has less than 25% errors up to 1 GHz.

  • An Efficient Routing Algorithm for Symmetrical FPGAs Using Reliable Cost Metrics

    Nak-Woong EUM  Inhag PARK  Chong-Min KYUNG  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E84-A No:3
      Page(s):
    829-838

    This paper presents a new performance and routability-driven routing algorithm for symmetrical array-based field-programmable gate arrays (FPGAs). The contribution of our work is to overcome one of the most critical limitations of the previous routing algorithms: inaccurate estimations of routing density which were too general for symmetrical FPGA. To this end, we devised new routing density measures that are directly linked to the structure (switch block) of symmetrical FPGA, and utilize them consistently in global and detailed routings. With the use of the proposed accurate routing metrics, we developed a new routing algorithm called a reliable net decomposition-based routing which is very fast, and yet produces excellent routing results in terms of net/path delays and routability. An extensive experiment was carried out to show the effectiveness of our algorithm based on the proposed cost metrics. In summary, when compared to the best known results in the literature (TRACER-fpga_PR and SEGA), our algorithm has shown 31.9% shorter longest path delay and 23.0% shorter longest net delay even with about 9 times faster execution time.

  • Higher Order Delta-Sigma AD Converter with Optimized Stable Coefficients

    Yikui ZHANG  Etsuro HAYAHARA  Satoshi HIRANO  

     
    PAPER-Analog Signal Processing

      Vol:
    E84-A No:3
      Page(s):
    813-819

    Optimization procedure on higher order Delta-sigma (ΔΣ) modulator coefficients is proposed. The procedure is based on the higher order ΔΣ modulator stability judgement method. The application specification can be satisfied with the proposed method. The 4th order modulator examples are illustrated. Optimized coefficients and its behavior model simulation results demonstrated that this methodology is suitable for the design of higher order ΔΣ AD converter. The coefficients tolerance up to 2% is allowed for switched-capacitor implementation, with not more than 3.5 dB SNR (Signal to Noise Ratio) degradation. The optimized coefficients improves 2 to 3 bit of the modulator's resolution than the previous proposed algorithm, and remains the stable input limit satisfies the original design requirement.

  • Balanced Bowtie and Trefoil Decomposition of Complete Tripartite Multigraphs

    Kazuhiko USHIO  Hideaki FUJIMOTO  

     
    PAPER-Graphs and Networks

      Vol:
    E84-A No:3
      Page(s):
    839-844

    First, we show that the necessary and sufficient condition for the existence of a balanced bowtie decomposition of the complete tripartite multi-graph λ Kn1,n2,n3 is (i) n1=n2=n3 0 (mod 6) for λ 1,5 (mod 6), (ii) n1=n2=n3 0 (mod 3) for λ 2,4 (mod 6), (iii) n1=n2=n3 0 (mod 2) for λ 3 (mod 6), and (iv) n1=n2=n3 2 for λ 0 (mod 6). Next, we show that the necessary and sufficient condition for the existence of a balanced trefoil decomposition of the complete tripartite multi-graph λ Kn1,n2,n3 is (i) n1=n2=n3 0 (mod 9) for λ 1,2,4,5,7,8 (mod 9), (ii) n1=n2=n3 0 (mod 3) for λ 3,6 (mod 9), and (iii) n1=n2=n3 3 for λ 0 (mod 9).

  • A New Formulation for Discrete Box Splines Reducing Computational Cost and Its Evaluation

    Takeshi ASAHI  Koichi ICHIGE  Rokuya ISHII  

     
    PAPER-Image

      Vol:
    E84-A No:3
      Page(s):
    884-892

    This paper presents a fast algorithm for calculating box splines sampled at regular intervals. This algorithm is based on the representation by directional summations, while splines are often represented by convolutions. The summation-based representation leads less computational complexity: the proposed algorithm requires fewer additions and much fewer multiplications than the algorithm based on convolutions. The proposed algorithm is evaluated in the sense of the number of additions and multiplications for three- and four-directional box splines to see how much those operations are reduced.

  • A Search Algorithm for Bases of Calderbank-Shor-Steane Type Quantum Error-Correcting Codes

    Kin-ichiroh TOKIWA  Hatsukazu TANAKA  

     
    PAPER-Coding Theory

      Vol:
    E84-A No:3
      Page(s):
    860-865

    Recently, Vatan, Roychowdhury and Anantram have presented two types of revised versions of the Calderbank-Shor-Steane code construction, and have also provided an exhaustive procedure for determining bases of quantum error-correcting codes. In this paper, we investigate the revised versions given by Vatan et al., and point out that there is no essential difference between them. In addition, we propose an efficient algorithm for searching for bases of quantum error-correcting codes. The proposed algorithm is based on some fundamental properties of classical linear codes, and has much lower complexity than Vatan et al.'s procedure.

  • Manipulation of Weber-Schafheitlin Integral for Conducting Wedge

    Huen-Tae HA  Jung-Woong RA  

     
    LETTER-Antenna and Propagation

      Vol:
    E84-B No:3
      Page(s):
    691-693

    This letter presents a new transformation technique of series solution to asymptotic solution for a perfectly conducting wedge illuminated by E-polarized plane wave. This transformation gives an analytic manipulation example of the Weber-Schafheitlin integral for diffraction problem.

  • High-Speed 2-D Parallel Optical Interconnects Using Image Fibers with VCSEL/PD Arrays

    Moriya NAKAMURA  Ken-ichi KITAYAMA  

     
    PAPER-Optical Interconnection Systems

      Vol:
    E84-C No:3
      Page(s):
    282-287

    Error-free transmission of image fiber-optic two-dimensional (2-D) parallel interconnection using vertical-cavity surface-emitting laser (VCSEL)/photodiode (PD) arrays is demonstrated. Simple constructions of transmitter/receiver modules are proposed. Optical alignment is achieved without power-monitoring. Crosstalk from an adjacent channel was -34 dB. Misalignment tolerance for a BER of less than 10-9 was 85 µm. The results clearly indicate that the interconnection system built around an image fiber and 2-D VCSEL/PD arrays has promise for use in the highly parallel high-density optical interconnects of the future.

  • Improvement of Active Net Model for Region Detection in an Image

    Noboru YABUKI  Yoshitaka MATSUDA  Makoto OTA  Yasuaki SUMI  Yutaka FUKUI  Shigehiko MIKI  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    720-726

    Processes in image recognition include target detection and shape extraction. Active Net has been proposed as one of the methods for such processing. It treats the target detection in an image as an energy optimization problem. In this paper, a problem of the conventional Active Net is presented and the new Active Net is proposed. The new net is improved the ability for detecting a target. Finally, the validity of the proposed net is confirmed by experimental results.

  • The Automatic Counting of Chlorella Using Image Processing and Neural Network

    Yasuaki SUMI  Makoto OTA  Noboru YABUKI  Shigeki OBOTE  Yoshitaka MATSUDA  Yutaka FUKUI  

     
    LETTER

      Vol:
    E84-A No:3
      Page(s):
    794-796

    In the culture of marine chlorellas, it is necessary to count the number in order to understand the condition of increase. For that propose, counting by the naked eye using the microscope has been used. However, this method requires a lot of time and work. We have developed the automatic chlorella counter using image processing and neural network. Its effectiveness is confirmed through the experiment.

  • PRIME ARQ: A Novel ARQ Scheme for High-Speed Wireless ATM

    Atsushi OHTA  Masafumi YOSHIOKA  Masahiro UMEHIRA  

     
    PAPER

      Vol:
    E84-B No:3
      Page(s):
    474-483

    Automatic repeat request (ARQ) for wireless ATM (WATM) operating at 20 Mbit/s or higher is required to achieve high throughput performance as well as high transmission quality, i.e., low CLR (cell loss ratio). Selective Repeat (SR) and Go-Back-N (GBN) are typical ARQ schemes. Though SR-ARQ is superior to GBN-ARQ in throughput performance, the implementation complexity of SR-ARQ's control procedures is disadvantageous to its application to high-speed wireless systems. In addition, when PDU (protocol data unit) length on wireless link is short, the capacity for ARQ control messages can be significantly large. GBN-ARQ, on the other hand, cannot avoid serious throughput degradation due to fairly high BER caused by multipath fading and shadowing, though its implementation is simple. To solve the above-mentioned problems, this paper proposes a novel ARQ scheme named PRIME-ARQ (Partial selective Repeat superIMposEd on gbn ARQ). PRIME-ARQ achieves high throughput performance, almost equal to selective repeat ARQ, with a simple algorithm resulting in reduced implementation complexity for high speed operation. This paper describes the design, implementation, and performance of the proposed PRIME-ARQ. In addition, it shows the experimental results using an experimental PRIME-ARQ hardware processor and proto-type AWA equipment.

  • An Effective Dynamic Priority List for 2-Processor Scheduling of Program Nets

    Qi-Wei GE  Akira TANAKA  

     
    PAPER

      Vol:
    E84-A No:3
      Page(s):
    755-762

    This paper aims at improving effectiveness of previously proposed hybrid priority lists, {L*i=LdLsi}, that are applied in nonpreemptive 2-processor scheduling of general acyclic SWITCH-less program nets, where Ld and Lsi are dynamic and static priority lists respectively. Firstly, we investigate the effectiveness of Ld through experiments. According to the experimental results, we reconstruct Ld to propose its improved list L1d. Then analyzing the construction methodology of the static priority lists {Lsi}, we propose a substituted list L2d by taking into account of the factor: remaining firing numbers of nodes. Finally, we combine a part of L1d and L2d to propose a new priority list L**. Through scheduling simulation on 400 program nets, we find the new priority list L** can generate shorter schedules, close to ones of GA (Genetic Algorithm) scheduling that has been shown exceedingly effective but costing much computation time.

23641-23660hit(30728hit)