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18401-18420hit(20498hit)

  • Flexible VLSI Architecture for Block-Matching Motion Estimation

    Han-Kyu LEE  Jae-Yeal NAM  Jin-Soo CHOI  Yeong-Ho HA  

     
    PAPER

      Vol:
    E79-D No:6
      Page(s):
    752-758

    Full-search block-matching motion estimation is a popular method to reduce temporal redundancies in video sequence. Due to its excessive computational load, parallel processing architectures are often required for real-time processing. One of the architectures is Hsieh's architecture based on systolic array processor and shift register arrays. Serial input characteristic of his scheme can reduce the number of pixel inputs to one, at the expense of significantly increasing the initialization time. This paper presents a modified and generalized Hsieh's architecture to reduce the initialization time. The proposed architecture can easily control data flows by rearranging shift register arrays and input-pin counts by using multiplexers on input stage, while retaining good properties of Hsieh's. The proposed architecture has the following advantages: (1) it allows controllable data inputs to save the pin counts, (2) it is flexible to the dimensional change of the search area via simple control, (3) it can operate in real time for video conference applications, and (4) it has simple and modular structure which is quite suitable for VLSI implementation. For verification of the proposed architecture, VHDL simulations are performed and some results are given.

  • Qualitative Decomposition and Recognition of Infrared Spectra

    Qi ZHAO  Toyoaki NISHIDA  

     
    PAPER-Artificial Intelligence and Cognitive Science

      Vol:
    E79-D No:6
      Page(s):
    881-887

    The objective of this paper is to provide an effective approach to infrared spectrum recognition. Traditionally, recognizing infrared spectra is a quantitative analysis problem. However, only using quantitative analysis has met two difficulties in practice: (1) quantitative analysis generally very complex, and in some cases it may even become intractable; and (2) when spectral data are inaccurate, it is hard to give concrete solutions. Our approach performs qualitative reasoning before complex quantitative analysis starts so that the above difficulties can be efficiently overcome. We present a novel model for qualitatively decomposing and analyzing infrared spectra. A list of candidates can be obtained based on the solutions of the model, then quantitative analysis will only be applied to the limited candidates. We also present a novel model for handling inaccuracy of spectral data. The model can capture qualitative features of infrared spectra, and can consider qualitative correlations among spectral data as evidence when spectral data are inaccurate. We have tested the approach against about 300 real infrared spectra. This paper also introduces the implementation of the approach.

  • Analytical Design of Optimum FIR Digital Integrators

    Ashwani KUMAR  Balbir KUMAR  

     
    PAPER

      Vol:
    E79-A No:6
      Page(s):
    764-767

    In this paper,novel techniques for designing Finite Impulse Response (FIR) digital integrators have been given. The design is based on analytical approach for computing the weights required in the structures. Exact mathematical formulas for computing these weights have been derived.

  • An Automated Thresholding Approach for Segmenting Deteriorated SEM Images in X-Ray Mask Visual Inspection

    Minoru ITO  

     
    PAPER-Image Processing,Computer Graphics and Pattern Recognition

      Vol:
    E79-D No:6
      Page(s):
    866-872

    The most troublesome problem in automated X-ray mask inspection is how to exactly determine the threshold level for extracting the pattern portions of each scanning electron microscopic (SEM) image. An exact determination is difficult because the histogram shows, in most cases, a complicated multi-modal pattern and the true threshold level often varies with each successive image. This paper presents a novel thresholding approach for segmenting SEM images of X-ray masks. In this approach, the shape of the histogram of each image is iteratively analyzed until a threshold value minimizing the cost of the correspondence with a reference histogram and satisfying criteria for determining thresholds is obtained. This new approach is used in an automated inspection system. When the input image resolution is set to 0.05µm/pixel, experiments confirm 0.1µm defects are unfailingly detected.

  • A Digitized Group Modulator Using Simple Fractional Sampling for Multi-Carrier TDMA Radio Systems

    Yoshifumi SUZUKI  Tadashi SHIRATO  

     
    PAPER-Radio Communication

      Vol:
    E79-B No:5
      Page(s):
    701-707

    This paper proposes a new digitized group modulator for radio base station transmitters of multi-carrier TDMA. This group modulator can flexibly set carrier spacing and features a simple construction as a result of employing the Simple Fractional Sampling technique. A group modulator LSI was designed and built using 0.5-µm BiCMOS technology, and a π/4-shifted QPSK group modulator was constructed using this LSI. Experiments confirm that the modulator simultaneously generates multiple carriers in a wide bandwidth without the need for precise adjustment and there is little difference between each of the carriers in terms of BER performance. Moreover, experiments confirm that the group modulator's burst-output (frequency hopping) performance is excellent.

  • Eugenics-Based Genetic Algorithm

    Ju YE  Masahiro TANAKA  Tetsuzo TANINO  

     
    PAPER-Artificial Intelligence and Cognitive Science

      Vol:
    E79-D No:5
      Page(s):
    600-607

    The problem of genetic algorithm's efficiency has been attracting the attention of genetic algorithm community. Over the last decade, considerable researches have focused on improving genetic algorithm's performance. However, they are generally under the framework of natural evolutionary mechanism and the major genetic operators, crossover and mutation, are activated by the prior probabilities. An operator based on a prior probability possesses randomness, that is, the unexpected individuals are frequently operated, but the expected individuals are sometimes not operated. Moreover, as the evaluation function is the link between the genetic algorithm and the problem to be solved, the evaluation function provides the heuristic information for evolutionary search. Therefore, how to use this kind of heuristic information (present and past) is influential in the efficiency of evolutionary search. This paper, as an attempt, presents a eugenics-based genetic algorithm (EGA) -- a genetic algorithm that reflects the human's decision will (eugenics), and fully utilizes the heuristic information provided by the evaluation function for the decisions. In other words, EGA = evolutionary mechanisms + human's decision will + heuristic information. In EGA, the ideas of the positive eugenics and the negative eugenics are applied as the principle of selections and the selections are not activated by the prior probabilities but by the evaluation values of individuals. A method of genealogical chain-based selection for mutation is proposed, which avoids the blindness of stochastic mutation and the disruptive problem of mutation. A control strategy of reasonable competitions is proposed, which brings the effects of crossover and mutation into full play. Three examples, the minimum problem of a standard optimizing function--De Jong's test function F2, a typical combinatorial optimization problem--the traveling salesman problem, and a problem of identifying nonlinear system, are given to show the good performance of EGA.

  • Subjective Evaluation of Perception of Delay Time between Visual Information and Tactile Information

    Tsutomu MIYASATO  Haruo NOMA  Fumio KISHINO  

     
    LETTER

      Vol:
    E79-A No:5
      Page(s):
    655-657

    This paper describes the results of tests that measured the allowable delay between images and tactile information via a force feedback device. In order to investigate the allowable delay, two experiments were performed: 1) subjective evaluation in real space and 2) subjective evaluation in virtual space using a force feedback device.

  • Pluralizing Method of Simple Similarity

    Yasuhiro AOKI  Taizo IIJIMA  

     
    PAPER-Classification Methods

      Vol:
    E79-D No:5
      Page(s):
    485-490

    For similarity methods to work well, the image must be blurred before being input. However, the relationship between the blurring operation and the similarity is not fully understood. To solve the problem of this relationship, in this paper, the effect of blurring is investigated by expressing figure f(x) in the form of the sum of higher derivatives of f (x,σ), and then a simple similarity between figures was mathematically formulated in terms of the relation between visual patterns. By modifying this formulation, we propose pluralized simple similarity to increase the allowance in different view of multiple similarity. The similarity maintains higher allowance without any discernible loss of distinguishing power. We verify the effectiveness of the pluralized simple similarity throughout some experiments.

  • Proposal and Performance Evaluation of a High-Speed Internetworking Device

    Akira WATANABE  Yuuji KOUI  Shoichiro SENO  Tetsuo IDEGUCHI  

     
    PAPER

      Vol:
    E79-B No:5
      Page(s):
    639-646

    We propose an architecture of a high-speed internetworking device using central control method. Co-operations of hardware and software is required to realize high relay performance. For the hardware, we have designed an original bus arbitration control method to achieve a high throughput of a data bus. For the software, we have devided a normal relay processing from other processing and built it as a basic function of the monitor. By this method, relay perfomance improves dramatically, because of a multiple effect of the reduction of software overheads and the improvement of cache hit ratio. We have developed the prototype device and confirmed the effects of the proposed method.

  • A Linear Array Antenna Using Bifilar Helical Elements for Mobile Satellite Communications

    Masataka OHTSUKA  Yoshihiko KONISHI  Makoto MATSUNAGA  Takashi KATAGI  

     
    PAPER-Passive Devices

      Vol:
    E79-C No:5
      Page(s):
    699-704

    In this paper, authors propose a linear array antenna using two bifilar helical antenna elements placed along the helix axis to reduce beam direction movement according to frequency change. The beam direction movement of this proposed array antenna is smaller than that of a conventional bifilar helical antenna. Also, the gain of this proposed array antenna is higher than that of the conventional helical antenna for a cross point angle of radiation patterns at the different transmit and receive(Tx and Rx) frequencies. The conventional helical antenna is suitable for vehicle antennas in mobile satellite communication systems such as the MSAT system because it owns circularly polarized omni-directional radiation pattern and its thin pole form. However, this antenna has a disadvantage that the beam direction in an elevation plane moves according to frequency change. In the proposed array antenna, the beam direction movement is about 9 smaller than that of the conventional bifilar helical antenna on condition that antenna total length is 4.83 λ0, antenna diameter is 0.12 λ0, and frequency change is from 0.957f0 to 1.043f0(f0 is center frequency and λ0 is free space wavelength at f0). Also, the Tx and Rx gains of this proposed array antenna at the cross point angle between Tx and Rx beams are about 2 dB higher than that of the conventional bifilar helical antenna on the same condition.

  • A Method for C2 Piecewise Quartic Polynomial Interpolation

    Caiming ZHANG  Takeshi AGUI  Hiroshi NAGAHASHI  

     
    PAPER-Image Processing,Computer Graphics and Pattern Recognition

      Vol:
    E79-D No:5
      Page(s):
    584-590

    A new global method for constructing a C2 piecewise quartic polynomial curve is presented. The coefficient matrix of equations which must be solved to construct the curve is tridiagonal. The joining points of adjacent curve segments are the given data points. The constructed curve reproduces exactly a polynomial of degree four or less. The results of experiments to test the efficiency of the new method are also shown.

  • Three-Year Measurement by VSAT System and CCIR Estimation for Rain Attenuation in Ku-Band Satellite Channel

    Jian KANG  Hiroshi ECHIGO  Koichi OHNUMA  Shigeo NISHIDA  Risaburo SATO  

     
    LETTER-Antennas and Propagation

      Vol:
    E79-B No:5
      Page(s):
    722-726

    The reception level of a round-trip signal from a VSAT (Very Small Aperture Terminal) was monitored continuously for three years starting October 1991.For these experimental measurements, a commercial satellite channel (up-link 14GHz/downlink 12GHz, bandwidth 100kHz) was used and rainfall was measured simultaneously. Data gathering time interval of 2 seconds was adopted to elucidate very rapid variation and lower percentage statistics. In this paper, attenuation due to rainfall is shown using the data obtained in this three-year period. It is shown that so far, the measured rain attenuation agrees very well with the values estimated using the CCIR model, and limits the range where the cumulative time exceeds 0.01%, even for our VSAT system in Tagajo, Miyagi Prefecture, Japan.

  • Improving the Hopfield Model for TSP Feasible Solutions by Synapse Dynamical Systems

    Yoshikane TAKAHASHI  

     
    PAPER-Neural Networks

      Vol:
    E79-A No:5
      Page(s):
    694-708

    It is well known that the Hopfield Model (HM) for neural networks to solve the TSP suffers from three major drawbacks: (D1) it can converge to non-optimal local minimum solutions; (D2) it can also converge to non-feasible solutions; (D3) results are very sensitive to the careful tuning of its parameters. A number of methods have been proposed to overcome (D1) well. In contrast, work on (D2) and (D3) has not been sufficient; techniques have not been generalized to larger classes of optimization problems with constraint including the TSP. We first construct Extended HMs (E-HMs) that overcome both (D2) and (D3). The extension of the E-HM lies in the addition of a synapse dynamical system cooperated with the corrent HM unit dynamical system. It is this synapse dynamical system that makes the TSP constraint hold at any final states for whatever choices of the HM parameters and an initial state. We then generalize the E-HM further into a network that can solve a larger class of continuous optimization problems with a constraint equation where both of the objective function and the constraint function are non-negative and continuously differentiable.

  • A Comparison between the Computational Power of PARBS and RMBM

    Kensuke MIYASHITA  Yoshihiro TSUJINO  Nobuki TOKURA  

     
    PAPER-Algorithm and Computational Complexity

      Vol:
    E79-D No:5
      Page(s):
    570-578

    Processor networks connected by buses have attracted considerable attention. Since a reconfigurable array is more powerful than a PRAM and more practical, it becomes the focus of attention. The Processor Array with Reconfigurable Bus System (PARBS) and the Reconfigurable Multiple Bus Machine (RMBM) are both models of parallel computation based on reconfigurable bus and processor array. The PARBS is a processor array that consists of processors arranged to a 2-dimensional grid with a reconfigurable bus system. The RMBM is also made of processors and reconfigurable bus system, but the processors are located in a row and the number of processors and the number of buses are independent of each other. Four versions of RMBM has been proposed and Extended RMBM (E-RMBM) is regarded as the most powerful one among them. In this paper, we describe that a PARBS of size N M can be simulated in constant time by a E-RMBM of 4NM processors, M + 3 buses and 1 read buffer, and that a E-RMBM of P processors, B buses and D read buffers can be also simulated in constant time by a PARBS of size B P. A PARBS or RMBM that solves a computational problem of size n is polynomially bounded iff the product of the number of processors and buses and red and write ports is O (nc), for some constant c. When a PARBS is polynomially bounded, the E-RMBM which simulates it is also polynomially bounded, and vice versa.

  • ATM Network Resource Management Techniques for CBR Virtual Paths/Channels

    Youichi SATO  Naoaki YAMANAKA  Ken-ichi SATO  

     
    PAPER-Communication Networks and Services

      Vol:
    E79-B No:5
      Page(s):
    684-692

    The benefits of ATM techniques have been widely recognized and many organizations envisage the introduction of ATM techniques into their telecommunication networks. The ATM benefits can, however, be fully exploited only after effective network resource management techniques have been developed. This paper focuses on CBR-VP management techniques. The ATM transport network architecture and VP roles are summarized. Next, the issues of VP accommodation design are described. The point is how to create a design that accommodates cell loss and cell delay jitter, both of which depend on various network parameters and conditions. For this purpose, analytical procedures based on an M/D/1 queueing model are adopted. The approximation method is shown to be very effective in practical use through computer analysis. The method guarantees conservative QOSs. Finally, the proposed method is applied to several design examples to illustrate VP management issues. The proposed method will enable ATM techniques to be introduced to our telecommunication networks by the mid-1990's.

  • Information Geometry of Mean Field Theory

    Toshiyuki TANAKA  

     
    PAPER-Neural Networks

      Vol:
    E79-A No:5
      Page(s):
    709-715

    The mean field theory has been recognized as offering an efficient computational framework in solving discrete optimization problems by neural networks. This paper gives a formulation based on the information geometry to the mean field theory, and makes clear from the information-theoretic point of view the meaning of the mean field theory as a method of approximating a given probability distribution. The geometrical interpretation of the phase transition observed in the mean field annealing is shown on the basis of this formulation. The discussion of the standard mean field theory is extended to introduce a more general computational framework, which we call the generalized mean field theory.

  • Handwritten Postal Code Recognition by Neural Network --A Comparative Study --

    Ahmad Fadzil ARIF  Hidekazu TAKAHASHI  Akira IWATA  Toshio TSUTSUMIDA  

     
    PAPER-Comparative Study

      Vol:
    E79-D No:5
      Page(s):
    443-449

    This paper compares some popular character recognition techniques which have been proposed until today. 17 feature extraction methods and 4 neural network based recognition processes were used in handwritten numerals (postal codes) recognition. It was found that Weighted Direction Index Histogram, Peripheral Direction Contributivity Function and Expansion Cell feature extractions gave good results. As for the neural network recognition process, CombNET- and multi layer neural network showed good performances.

  • Estimation of Aortic Flow and Pressure Volume Loop by Optimal Control Theory

    Hirohumi HIRAYAMA  Yuzo FUKUYAMA  

     
    LETTER

      Vol:
    E79-A No:5
      Page(s):
    642-651

    We have shown a non-invasive method for estimating transient changes in aortic flow and ventricular volume based on optimal control theory by using successful simulations of reported experimental data. The performance function to evaluate the optimality of the cardiovascular system was proposed based oh physical, fluid mechanical and pathophysiological considerations. It involved the work of the ventricle, the rate of changes in the aortic flow and the ventricular pressure. We determined that the cardiovascular system operates optimally when the performance function has been minimized. The relative magnitudes of the reductions of changes in these terms were expressed by the weighting coefficients. The arterial system was described by the Wind Kessel model using arterial resistance, aortic compliance and aortic valvular resistance. We set boundary conditions and transitional conditions derived from the systolic and diastolic phases of the aortic flow and the arterial pressure. The optimized system equations were converted to 6 linear simultaneous differential equations with 6 boundary conditions. The optimal ventricular pressure and aortic flow rate that minimize the performance function were obtained by solving these differential equations. By alternating the weighting coefficients of the work of ventricle and the rate of change in the ventricular ejection pressure, successful simulations of the ventricular pressures recorded from human subjects and those from isolated canine ventricle were obtained. Once the sets of weighting coefficients had been determined by successful simulations of ventricular pressures, the calculated aortic flow curves and pressure volume loops by the present method coincided with the reported experimental data. The changes in ventricular pressure and aortic flow produced by alternating the weighting coefficients to simulate the reported ventricular pressures and aortic flow curves under the different afterload conditions were consistent with biophysical experimental data. The present method is useful to estimata aortic flow curve and ventricular pressure volume loops non-invasively.

  • A Half-Chip Offset QPSK Modulation CDMA Scheme Employing Differential Detection for Advanced Wireless LAN Systems

    Takatoshi SUGIYAMA  Masato MIZOGUCHI  Shuji KUBOTA  

     
    PAPER-Radio Communication

      Vol:
    E79-B No:5
      Page(s):
    693-700

    This paper proposes a half-chip offset QPSK (Quadrature Phase Shift Keying) modulation CDMA (Code Division Multiple Access) scheme to allow the simple differential detection while realizing a compact spectrum in nonlinear channels for wireless LAN systems. The experimental results show the proposed scheme achieves excellent Pe (probability of error) performances in ACI (adjacent channel interference) and CCI (co-channel interference) environments. Moreover, by employing time diversity and high-coding-gain FEC (Forward Error Correction), the half-chip offset QPSK-CDMA scheme realizes an improvement of 3.0 dB (in terms of Eb/No at a Pe of 105) in Rician fading environments with a Doppler frequency fD of 10 Hz and a delay spread of 40 nsec.

  • Self-Tuning of Fuzzy Reasoning by the Steepest Descent Method and Its Application to a Parallel Parking

    Hitoshi MIYATA  Makoto OHKI  Masaaki OHKITA  

     
    PAPER-Algorithm and Computational Complexity

      Vol:
    E79-D No:5
      Page(s):
    561-569

    For a fuzzy control of manipulated variable so as to match a required output of a plant, tuning of fuzzy rules are necessary. For its purpose, various methods to tune their rules automatically have been proposed. In these method, some of them necessitate much time for its tuning, and the others are lacking in the generalization capability. In the fuzzy control by the steepest descent method, a use of piecewise linear membership functions (MSFs) has been proposed. In this algorithm, MSFs of the premise for each fuzzy rule are tuned having no relation to the other rules. Besides, only the MSFs corresponding to the given input and output data for the learning can be tuned efficiently. Comparing with the conventional triangular form and the Gaussian distribution of MSFs, an expansion of the expressiveness is indicated. As a result, for constructing the inference rules, the training cycles can be reduced in number and the generalization capability to express the behavior of a plant is expansible. An effectiveness of this algorithm is illustrated with an example of a parallel parking of an autonomous mobile robot.

18401-18420hit(20498hit)