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2781-2800hit(3161hit)

  • High Legible Color Display Tube

    Nobumitsu AIBARA  Akira SHISHIDO  Yoshiaki YANAI  Akihiro KAMADA  Masaru TOGAWA  

     
    INVITED PAPER

      Vol:
    E80-C No:8
      Page(s):
    1075-1078

    The CROMACLEAR color display tube has been developed as a display that offers attractive icon quality and highly legible characters. The color display tube is composed of a striped superfine pitch phosphor screen with slot-type shadow mask. We explain the character legibility by Fourier transform. Moreover, the electron beam shape is improved. As a result, the CROMACLEAR color display tube has achieved higher legibility and lower moire phenomenon. This CROMACLEAR color display tube is already mounted in new monitor series.

  • Reduction of Gibbs Overshoot in Continuous Wavelet Transform

    Handa CHEN  Yasuhiro KAWAI  Hajime MAEDA  

     
    PAPER

      Vol:
    E80-A No:8
      Page(s):
    1352-1361

    In this paper we propose two methods, named the time smoothing and the scale smoothing respectively, to reduce the Gibbs overshoot in continuous wavelet transform. In is shown that for a large kind of wavelets the scale smoothing cannot remove the Gibbs overshoot completely as in the case of Fourier analysis, but it is possible to reduce the overshoot for any wavelets by choosing the smoothing window functions properly. The frequency behavior of scale smoothing is similar to that of the time smoothing. According to its frequency behavior we give the empirical conditions for selecting the smoothing window functions. Numerical examples are given for illustrations.

  • Numerical Analysis of the MC Scheme and Investigation of the Effects of Its Parameters

    Jaehong PARK  Cheeha KIM  

     
    PAPER-Switching and Communication Processing

      Vol:
    E80-B No:7
      Page(s):
    1016-1026

    ATM (Asynchronous Transfer Mode) has been standardized by ITU-T, in order to realize the broadband ISDN. Due to its properties, such as packet-oriented information transfer without flow control and flexible allocation of transmission capacity, in order to ensure quality of service for all existing calls, it is necessary to monitor and regulate the traffic for each call based on traffic descriptor. This kind of control is done by a policing function. There are many proposed policing schemes. Among them, the MC (Moving Ceiling) scheme is considered as an efficient mean cell rate policing scheme. It has been recently proposed and proved to have a promising performance in mean cell rate enforcement by simulation. In this paper, we formulate numerical equations to calculate the steady state probability and output rate of the MC scheme. And using them, we investigate the effects of MC parameters on its performance.

  • Deferred Locking with Buffer Validation on Demand for Client-Server Database Consistency: DL

    Hyeokmin KWON  Songchun MOON  

     
    PAPER-Databases

      Vol:
    E80-D No:7
      Page(s):
    705-716

    In client-server database management systems (DBMSs), inter-transaction caching is an effective technique for improving the performance. However, inter-transaction caching requires a cache consistency maintenance (CCM) protocol to ensure that cached copies at clients are kept mutually consistent. Such a protocol could be complex to implement and expensive to run, since several rounds of message exchange may be required. In this paper, we propose a new CCM scheme based on the primary-copy locking algorithm. In the proposed scheme, a number of lock requests and a data-shipping request are combined into a single message packet to reduce client-server interactions, which are known to be very critical to the performance of clientserver DBMSs. We examine its performance tradeoffs on the basis of a simulation model under a wide range of workloads. The performance results indicate that the proposed scheme improves the overall system throughput significantly over the caching two-phase locking and the optimistic two-phase locking scheme. Its higher performance mainly results from its lower communication overhead and lower degree of transaction blocking ratio.

  • Histogram Matching by Moment Normalization

    Wen-Hao WANG  Yung-Chang CHEN  

     
    LETTER-Image Processing,Computer Graphics and Pattern Recognition

      Vol:
    E80-D No:7
      Page(s):
    746-750

    A moment-based method is proposed to estimate the illumination change between two images containing affinetransformed objects. The change is linearly modeled with parameters to be estimated by histograms due to its invariance of translation, rotation, and scaling. The parameters can be correctly estimated for an appropriate illumination change by normalizing the moments of the histograms.

  • On Irregular Sampling in Wavelet Subspaces

    Wen CHEN  Shuichi ITOH  

     
    PAPER-General Fundamentals and Boundaries

      Vol:
    E80-A No:7
      Page(s):
    1299-1307

    The paper provides the algorithm to estimate the deviation bound admitting to recovering irregularly sampled signals in wavelet subspaces, which does not need the symmetricity sampling constraint of Paley-Wiener's and relaxes the deviation bounds in some wavelet subspaces. Meanwhile the method does not need the continuity and decay constraints imposed on scaling functions by Liu-Walter and Chen-Itoh-Shiki.

  • A Wavelet View for Unifying Boolean Discrete Functions and Neural Nets through Haar Transform

    Masatoshi SEKINE  

     
    PAPER-Neural Networks and Chips

      Vol:
    E80-C No:7
      Page(s):
    1003-1009

    Spectral transform methods have been widely studied for classification and analysis of logic functions. Spectral methods have also been used for logic synthesis, and by use of BDDs, practical-sized synthesis problems have been solved. Wavelet theory has recently attracted the attention of researchers in the signal processing field. The Haar function is used in both spectral methods and in signal processing to obtain spectral coefficients of logic functions of signals. In this paper spectral transform-based analysis of neural nets verifying signal processing and discrete function is presented. A neural net element is defined as a discrete function with multi-valued input signals and multi-valued or binary outputs. The multi-valued variable is realized as a variable (V, W) formed by a pair of a binary value and a multi-value pulse width. The multi-valued encoding is used with the multi-valued Haar function to give meanings to the wavelet coefficients from the view of Boolean algebra. A design example shows that these conceptually different concepts are closely related.

  • Piezoelectric Transformer Converter with PWM Control

    Toshiyuki ZAITSU  Tamotsu NINOMIYA  Masahito SHOYAMA  

     
    PAPER-Power Supply

      Vol:
    E80-B No:7
      Page(s):
    1035-1044

    A piezoelectric transformer (PT) converter with PWM control is presented. The combination of an active-clamp circuit and a resonant circuit makes it possible to control the output voltage of the PT converter with PWM at a constant switching frequency. The PT converter circuit is evaluated using an AC analysis, and a design procedure is presented. The PT converter implemented on a printed circuit board is experimentally evaluated and a good controllability is successfully achieved.

  • Frame Operator Approach for Designing Discrete-Time Multiple Short-Time Fourier Transform and Its Time-Frequency Distribution

    Shigeo WADA  Hideki YAGI  Hiroshi INABA  

     
    PAPER

      Vol:
    E80-A No:6
      Page(s):
    977-986

    This paper presents a discrete-time multiple short-time Fourier transform (MSTFT) suitable for a time-frequency analysis and synthesis of discrete-time nonstationary signals. An overcomplete set of multiple windows in used for a frame constitution in l2 (Z) so that higher quality signal analysis and perfect reconstruction of the signal are achieved. A design method for a prototype window is given where the window can satisfy regularity condition and have a flexible, good time and frequency characteristic under constraint of the uncertainty principle. A dual frame is constructed using the prototype windows in the framework of a frame operator method. Efficient implementation structures for the MSTFT and its inverse transform appropriate for real time numerical processing is presented. Simulation results are given to illustrate the effectiveness for design of the MSTFT. The performance advantages as a new signal analysis tool are demonstrated with an experimental signal.

  • A New State Space-Based Approach for the Estimation of Two-Dimensional Frequencies and Its Parallel Implementations

    Yi CHU  Wen-Hsien FANG  Shun-Hsyung CHANG  

     
    PAPER-Digital Signal Processing

      Vol:
    E80-A No:6
      Page(s):
    1099-1108

    In this paper, we present a new state space-based approach for the two-dimensional (2-D) frequency estimation problem which occurs in various areas of signal processing and communication problems. The proposed method begins with the construction of a state space model associated with the noiseless data which contains a summation of 2-D harmonics. Two auxiliary Hankel-block-Hankel-like matrices are then introduced and from which the two frequency components can be derived via matrix factorizations along with frequency shifting properties. Although the algorithm can render high resolution frequency estimates, it also calls for lots of computations. To alleviate the high computational overhead required, a highly parallelizable implementation of it via the principle subband component (PSC) of some appropriately chosen transforms have been addressed as well. Such a PSC-based transform domain implementation not only reduces the size of data needed to be processed, but it also suppresses the contaminated noise outside the subband of interest. To reduce the computational complexity induced in the transformation process, we also suggest that either the transform of the discrete Fourier transform (DFT) or the Haar wavelet transform (HWT) be employed. As a consequence, such an approach of implementation can achieve substantial computational savings; meanwhile, as demonstrated by the provided simulation results, it still retains roughly the same performance as that of the original algorithm.

  • Analysis Method of Nonstationary Waveforms Based on a Modulation Model

    Yumi TAKIZAWA  Atsushi FUKASAWA  

     
    PAPER

      Vol:
    E80-A No:6
      Page(s):
    951-957

    An analysis method is proposed for nonstationary waveforms. Modelling of a nonstationary waveform is first given in this paper. A waveform is represented by multiple oscillations. The instantaneous phase angle of each oscillation is written by three terms, predictive component, residual component, and initial phase constant. By this modelling, waveform analysis results in estimations of frequency, calculation of residual pbase in instantaneous phase angle. The Instantaneous Maximum Entropy Methods (IMEN) is utilized for frequency estimation. The residual phase angle is obtained by the Vandermonde matrix and the condition of continuity of phase angle among n-neighbourhood. Another analysis method is also proposed by the normalization of waveform parameters. The evaluation of the proposed method is done using artificially composed waveform signals. Novel and useful knowledge was provided by this analysis.

  • Service Usage Information Management for Multimedia Services

    Masaharu MORIHIRO  Takahiko MORI  

     
    PAPER-Architecture/Modeling

      Vol:
    E80-B No:6
      Page(s):
    827-832

    Given the recent advances in telecommunication services, new service operations are needed that support not only existing network services, but also information and communication providing services, such as multimedia services. It is particularly important that service usage information should be gathered, processed, analyzed and presented properly for smooth service provisioning and business support. This paper defines a reference model for service usage information and an implementation model for establishing the functions needed to gather and process this information. The results of an service operation system as implemented in NTT multimedia service trials, currently underway in the city of Urayasu, are also described.

  • Competitive Telecommunications Management and System Development

    Masayoshi EJIRI  

     
    INVITED PAPER

      Vol:
    E80-B No:6
      Page(s):
    805-810

    Rapid advancing technology and customer demand for sophisticated services are driving the global telecommunications environment into fully competitive and multi service providers environment. To cope with this new environment successfully, open network and open telecommunication management are essential. Telecommunication management is becoming more and more important to realize flexible and dynamic telecommunication services. This paper first gives a view of the new environment in the telecommunication industry and discusses the direction to be taken by service providers. Then, a concept of multi-domain management is proposed to meet a dynamically changing environment. Finally, the paper describes the subjects for the development of telecommunication management system and suggests that a competition based on harmony between the users, service providers and vendors is needed to make customers satisfied with telecommunication services.

  • Reducing the Number of Synchronization Operations in Protocol Conformance Testing

    Wen-Huei CHEN  

     
    LETTER-Communication Software

      Vol:
    E80-B No:6
      Page(s):
    970-973

    Conformance testing is to see if the protocol implementation conforms to its specification. A lot of test sequences have been developed for testing centers. Yet directly applying these test sequences to the simple testing system in laboratories suffers from the frequently-occurred synchronization problems. This paper proposes a new technique to disconnect a test sequence into segments based on their functions, and reconnects them into a new test sequence that simulates these functions yet suffers less from the synchronization problems.

  • Detection and Processing of Lightning-Sourced Magnetotelluric Transients with the Wavelet Transform

    Yuanchou ZHANG  David GOLDAK  Ken PAULSON  

     
    PAPER-Digital Signal Processing

      Vol:
    E80-A No:5
      Page(s):
    849-858

    In audio-frequency magnetotelluric surveys, electromagnetic radiation from worldwide thunderstorm activity is used as an energy source for geophysical exploration. Owing to its origin, such a signal is inherently transient and short lived. Therefore, special care should be taken in the detection and processing of this transient signal because the interval of time between two successive transient events contains almost no information as far as the audio frequency magnetotellurist is concerned. In this paper, a wavelet transform detection, processing and analysis technique is developed. A complex-compactly-supported wavelet, known as the Morlet wavelet, is selected as the mother wavelet. With the Morlet wavelet, lightning transients can be easily identified in the noisy recordings and the magnetotelluric impedance tensor can be computed directly in the wavelet transform domain. This scheme has been tested on real data collected in the archipelago of Svalbard, Norway as well as on five sets of synthetic data contaminated with various kinds of noise. The results show the superior performance of the wavelet transform transient detection and analysis technique.

  • Computational Power of Nondeterministic Ordered Binary Decision Diagrams and Their Subclasses

    Kazuyoshi TAKAGI  Koyo NITTA  Hironori BOUNO  Yasuhiko TAKENAGA  Shuzo YAJIMA  

     
    PAPER

      Vol:
    E80-A No:4
      Page(s):
    663-669

    Ordered Binary Decision Diagrams (OBDDs) are graph-based representations of Boolean functions which are widely used because of their good properties. In this paper, we introduce nondeterministic OBDDs (NOBDDs) and their restricted forms, and evaluate their expressive power. In some applications of OBDDs, canonicity, which is one of the good properties of OBDDs, is not necessary. In such cases, we can reduce the required amount of storage by using OBDDs in some non-canonical form. A class of NOBDDs can be used as a non-canonical form of OBDDs. In this paper, we focus on two particular methods which can be regarded as using restricted forms of NOBDDs. Our aim is to show how the size of OBDDs can be reduced in such forms from theoretical point of view. Firstly, we consider a method to solve satisfiability problem of combinational circuits using the structure of circuits as a key to reduce the NOBDD size. We show that the NOBDD size is related to the cutwidth of circuits. Secondly, we analyze methods that use OBDDs to represent Boolean functions as sets of product terms. We show that the class of functions treated feasibly in this representation strictly contains that in OBDDs and contained by that in NOBDDs.

  • Beam Forming Characteristics of a Waveguide-Type Optical Phased Array Antenna

    Yasushi MURAKAMI  Keizo INAGAKI  Yoshio KARASAWA  

     
    PAPER-Antennas and Propagation

      Vol:
    E80-B No:4
      Page(s):
    617-624

    This paper presents the beam forming characteristics of an optical waveguide-type phased array antenna. Four linearly arranged array antenna was monolithically fabricated on one LiNbO3 substrate containing variable power dividers (VPDs) and optical phase shifters (OPSs). The amplitude and the phase of each antenna element was controlled by applying DC voltage on each VPD and OPS. Open ends of Ti-indiffused waveguides were used as antenna elements. This antenna was designed to operate at 1.3 µm wavelength band. Experimental results confirm the good beam forming capability of optical phased array antennas.

  • Classification of Planar Curve Using the Zero-Crossings Representation of Wavelet Transform

    Dodi SUDIANA  Nozomu HAMADA  

     
    LETTER-Digital Signal Processing

      Vol:
    E80-A No:4
      Page(s):
    775-777

    A method of planar curve classification, which is invariant to rotation, scaling and translation using the zerocrossings representation of wavelet transform was introduced. The description of the object is represented by taking a ratio between its two adjacent boundary points so it is invariant to object rotation, translation and size. Transforming this signal to zero-crossings representation using wavelet transform, the minimum distance between the object and model while shifting the signals each other, can be used as classification parameter.

  • Vienna Fortran and the Path Towards a Standard Parallel Language

    Barbara M. CHAPMAN  Piyush MEHROTRA  Hans P. ZIMA  

     
    INVITED PAPER

      Vol:
    E80-D No:4
      Page(s):
    409-416

    Highly parallel scalable multiprocessing systems (HMPs) are powerful tools for solving large-scale scientific and engineering problems. However, these machines are difficult to program since algorithms must exploit locality in order to achieve high performance. Vienna Fortran was the first fully specified data-parallel language for HMPs that provided features for the specification of data distribution and alignment at a high level of abstraction. In this paper we outline the major elements of Vienna Fortran and compare it to High Performance Fortran (HPF), a de-facto standard in this area. A significant weakness of HPF is its lack of support for many advanced applications, which require irregular data distributions and dynamic load balancing. We introduce HPF +, an extension of HPF based on Vienna Fortran, that provides the required functionality.

  • The Coefficients of Daubechies's Scaling Functions on the Wavelet Transform

    Kiyoshi OKADA  

     
    LETTER-Digital Signal Processing

      Vol:
    E80-A No:4
      Page(s):
    771-774

    A new method to obtain the coefficients of Daubechies's scaling functions is given, in which it is not necessary to find the complex zeros of polynomials. Consequently it becomes easier to obtain the coefficients of arbitrary order from 2 to 40 with high accuracy.

2781-2800hit(3161hit)