The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] SC(4570hit)

3681-3700hit(4570hit)

  • Newly Found Visual Illusions and 3-D Display

    Masanori IDESAWA  Qi ZHANG  

     
    REVIEW PAPER

      Vol:
    E82-C No:10
      Page(s):
    1823-1830

    Human visual system can perceive 3-D structure of an object by binocular disparity, gradient of illumination (shading), occlusion, textures, perspective and so forth. Among them, binocular disparity seems to be the essentially important cues for the 3-D space perception and it is used widely for displaying 3-D visual circumstances such as in VR (virtual reality) system or 3-D TV. Visual illusions seem to be one of the phenomena which are purely reflecting the mechanism of human visual system. In the recent several years, the authors found several new types of 3-D visual illusions with binocular viewing. Entire 3-D illusory object including volume perception, transparency, dynamic illusions can be perceived only from the visual stimuli of disparity given by some inducing objects arranged with suitable relations. In this report, the authors introduced these newly found visual illusions and made some considerations on the human visual mechanism of 3-D perception and on their exploitation for new effective techniques in 3-D display. They introduced especially on the visual effect in two kinds of arrangement with occlusion and sustaining relationship between the illusory object and inducing objects. In the former case, the inducing objects which provide the stimuli were named as occlusion cues and classified into two types: contour occlusion cues and bulky occlusion cues. In the later case, those inducing objects were named as sustaining cues and a 3-D fully transparent illusory object was perceived. The perception was just like imagined from the scenes of the actions and positions of the pantomimists; then this phenomena was named as "Mime (Pantomime) Effect. " According to the positions of sustaining cues, they played different actions in this perception, and they are classified into three types: front sustaining cues, side sustaining cues and back sustaining cues. In addition, dynamic fusion and separation of volumetrical illusory objects were perceived when the visual stimuli were moving continuously between two structurally different conditions. Then the hysteresis was recognized in geometrical position between the fusion and separation. The authors believe that the occlusion cues and sustaining cues introduced in this paper could be effective clues for exploiting the new techniques for 3-D display.

  • Application of Mix-Phase Wavelets to Sparsify Impedance Matrices

    Jiunn-Ming HUANG  Jeng-Long LEOU  Shyh-Kang JENG  Jenn-Hwan TARNG  

     
    LETTER-Optical Communication

      Vol:
    E82-B No:10
      Page(s):
    1688-1693

    Effective wavelets to solve electromagnetic integral equations are proposed. It is based on the same construction procedure as Daubechies wavelets but with mix-phase to obtain maximum sparsity of moment matrix. These new wavelets are proved to have excellent performance in non-zero elements reduction in comparison with minimum-phase wavelet transform (WT). If further sparsity is concerned, wavelet packet (WP) transform can be applied but increases the computational complexity. In some cases, the capability of non-zero elements reduction by this new wavelets even better than WP with minimum-phase wavelets and with less computational efforts. Numerical experiments demonstrate the validity and effectiveness of the new wavelets.

  • Learning Bayesian Belief Networks Based on the Minimum Description Length Principle: Basic Properties

    Joe SUZUKI  

     
    PAPER-Information Theory and Coding Theory

      Vol:
    E82-A No:10
      Page(s):
    2237-2245

    This paper addresses the problem of learning Bayesian belief networks (BBN) based on the minimum description length (MDL) principle. First, we give a formula of description length based on which the MDL-based procedure learns a BBN. Secondly, we point out that the difference between the MDL-based and Cooper and Herskovits procedures is essentially in the priors rather than in the approaches (MDL and Bayesian), and recommend a class of priors from which the formula is obtained. Finally, we show as a merit of using the formula that a modified version of the Chow and Liu algorithm is obtained. The modified algorithm finds a set of trees rather than a spanning tree based on the MDL principle.

  • Problems and Present Status of Phosphors in Low-Voltage Full-Color FEDs

    Shigeo ITOH  Hitoshi TOKI  Fumiaki KATAOKA  Yoshitaka SATO  Kiyoshi TAMURA  Yoshitaka KAGAWA  

     
    PAPER

      Vol:
    E82-C No:10
      Page(s):
    1808-1813

    For the realization of low-voltage full-color FEDs, requirements for phosphor for the FED are proposed. Especially, the influence of released gases or substances from phosphors on the field emission within the FED was made clear. It was clarified that the analysis of F-N plots of the V-I curve of field emission characteristics was helpful to know the interaction of field emission and phosphors. In the experiment, we first obtained the depth from the phosphor surface of the low voltage electron excitation in case of ZnGa2O4, where the region available for cathodoluminescence at the anode voltage of 400 V is about 63 nm deep from the surface. The characteristic of the 12.4 cm-320(trio)240 pixels low-voltage full-color FED is reported. The luminance of 154 cd/m2 was attained at the anode voltage of 400 V and the duty factor of 1/241. Supported by the high potential of the FED as a flat panel, each problem shall be steadily solved to secure the firm stand as a new full color flat display in new applications.

  • A Wide-Viewing-Angle π Cell Compensated with a Discotic Film

    Hiroyuki MORI  

     
    PAPER

      Vol:
    E82-C No:10
      Page(s):
    1787-1791

    We have realized excellent viewing angle characteristics for the π cell, by combining a discotic negative birefringence film, which has a hybrid alignment structure, and a positive a-plate. The negative birefringence of the film completely compensates the positive birefringence of the π cell liquid crystals in the dark-state. The roll of a c-plate, which should be accompanied by the a-plate to suppress the light leakage from crossed polarizer at oblique incident angles, was substituted for the vertically aligned component of the π cell liquid crystal. Taking into account the fast electrooptical response, which is one order faster than that of the twisted-nematic liquid-crystal display, the π cell is one of the most promising liquid-crystal-display modes.

  • Enhanced Backscattering from Random Media with Multiple Suspensions

    Yasuyuki OKAMURA  Hiroyuki KAI  Sadahiko YAMAMOTO  

     
    PAPER-Electromagnetic Theory

      Vol:
    E82-C No:10
      Page(s):
    1853-1856

    Experiment is reported of enhanced backscattering of light in binary and ternary suspensions of rutile and/or alumina particles. With a conventional CCD camera system for observing the phenomena, the angular line shape and the enhancement factor were agreed with the theoretically predicted curve and value. Observation of the angular distribution scattered at the backscattered direction supported the hypothesis proposed by Pine et al. , in which the transport mean free path of the polydisperse mixture can be expressed in terms of summing its reciprocal values weighted over the particle sizes.

  • Analysis of Modified Luneberg Lens Using Exact Solutions

    Haruo SAKURAI  Makoto OHKI  Shogo KOZAKI  

     
    PAPER-Electromagnetic Theory

      Vol:
    E82-C No:10
      Page(s):
    1846-1852

    Analytical solutions have been obtained for the electromagnetic scattering by a modified Luneberg lens with the permittivity of arbitrary parabolic function. They are expressed by four spherical vector wave functions for radially stratified medium which were introduced for the Luneberg lens by C. T. Tai. They consist of the confluent hypergeometric function and a "generalized" confluent hypergeometric function, in which the parameters for the permittivity of arbitrary parabolic function are involved. The characteristics of the modified Luneberg lens are numerically investigated using exact solutions in comparison with that of the conventional Luneberg lens. The bistatic cross section, the forward cross section and the radar cross section are studied in detail. The near-field distribution is also investigated in order to study the focal properties of the Luneberg lens. The focal shifts defined by the distance between the geometrical focal point and the electromagnetic focal point are obtained for various ka (k is the wave number and a is the radius of the lens). The focal shift normalized to the radius of the sphere becomes larger as ka is smaller. However it drops down rapidly for ka5 when the peak of the electric field amplitude appears on the surface of sphere.

  • Application of Wavelets to Scattering Problems of Inhomogeneous Dielectric Slabs

    Jeng-Long LEOU  Jiunn-Ming HUANG  Shyh-Kang JENG  Hsueh-Jyh LI  

     
    PAPER-Electronic and Radio Applications

      Vol:
    E82-B No:10
      Page(s):
    1667-1676

    In this paper, we apply the discrete wavelet transform (DWT) and the discrete wavelet packet transform (DWPT) with the Daubechies wavelet of order 16 to effectively solve for the electromagnetic scattering from a one-dimensional inhomogeneous slab. Methods based on the excitation vector and the [Z] matrix are utilized to sparsify an MoM matrix. As we observed, there are no much high frequency components of the field in the dielectric region, hence the wavelet coefficients of the small scales components (high frequency components) are very small and negligible. This is different from the case of two-dimensional scattering from perfect conducting objects. In the excitation-vector-based method, a modified excitation vector is introduced to extract dominant terms and achieve a better compression ratio of the matrix. However, a smaller compression ratio and a tiny relative error are not obtained simultaneously owing to their deletion of interaction between different scales. Hence, it is inferior to the [Z]-matrix-based methods. For the [Z]-marix-based methods, our numerical results show the column-tree-based DWPT method is a better choice to sparsify the MoM matrix than DWT-based and other DWPT-based methods. The cost of a matrix-vector multiplication for the wavelet-domain sparse matrix is reduced by a factor of 10, compared with that of the original dense matrix.

  • A Preemptive Priority Handoff Scheme in Integrated Voice and Data Cellular Mobile Systems

    Bo LI  Qing-An ZENG  Kaiji MUKUMOTO  Akira FUKUDA  

     
    PAPER-Mobile Communication

      Vol:
    E82-B No:10
      Page(s):
    1633-1642

    In this paper, we propose a preemptive priority handoff scheme for integrated voice/data cellular mobile systems. In our scheme, calls are divided into three different classes: handoff voice calls, originating voice calls, and data calls. In each cell of the system there is a queue only for data calls. Priority is given to handoff voice calls over the other two kinds of calls. That is, the right to preempt the service of data is given to a handoff voice call if on arrival it finds no idle channels. The interrupted data call returns to the queue. The system is modeled by a two-dimensional Markov chain. We apply the Successive Over-Relaxation (SOR) method to obtain the equilibrium state probabilities. Blocking and forced termination probabilities for voice calls are obtained. Moreover, average queue length and average transmission delay of data calls are evaluated. The results are compared with another handoff scheme for integrated voice/data cellular mobile systems where some numbers of channels are reserved for voice handoff calls. It is shown that, when the data traffic is not very light, the new scheme can provide lower blocking probability for originating voice calls, lower forced termination probability for ongoing voice calls, and shorter average queue length and less average transmission delay for data calls.

  • Additive Noise Response of a Charge Pump Phase-Locked Loop

    Bishnu Charan SARKAR  Muralidhar NANDI  

     
    LETTER-Analog Signal Processing

      Vol:
    E82-A No:10
      Page(s):
    2291-2293

    The additive noise response of a charge pump phase-locked loop in the synchronous mode of operation has been studied. In order to determine the tracking and noise performances of the loop, mean square values of tracking error and local oscillator phase jitter have been analytically obtained. Analytical results agree well with the simulation results obtained here and elsewhere. The analysis performed can be used in choosing different system parameters for optimum system operation.

  • Bifurcation Phenomena of 1/2-Subharmonic Oscillations in Three-Phase Circuit

    Takashi HISAKADO  Kohshi OKUMURA  

     
    PAPER-Nonlinear Problems

      Vol:
    E82-A No:9
      Page(s):
    1919-1925

    This paper presents the several bifurcation phenomena generated in nonlinear three-phase circuit with symmetry. The circuit consists of delta-connected nonlinear inductors, capacitors and three-phase symmetrical voltage sources. Particular attention is paid to the subharmonic oscillations of order 1/2. We analyze the bifurcations of the oscillations from both theoretical and experimental points. As a tool of analysis, we use the homotopy method. Additionally, by comparing with single-phase and single-phase-like circuits, the special feature of the three-phase circuit is revealed.

  • Evolution of Arnold's Tongues in a Z2-Symmetric Electronic Circuit

    Antonio ALGABA  Manuel MERINO  Alejandro J. RODRIGUEZ-LUIS  

     
    PAPER

      Vol:
    E82-A No:9
      Page(s):
    1714-1721

    In this paper we study the evolution of the resonance zones that appear in connection with a Hopf-pitchfork bifurcation exhibited by a Z2-symmetric electronic circuit. These regions, bounded by curves of folds (saddle-node bifurcations) may be closed or open depending on the values of the parameters. An angular degeneracy on the torus bifurcation curve originates the banana shape of Arnold's tongues. The presence of homoclinic bifurcations is also pointed out.

  • Realization of a Four Parameter Family of Generalized One-Dimensional Contact Interactions by Three Nearby Delta Potentials with Renormalized Strengths

    Takaomi SHIGEHARA  Hiroshi MIZOGUCHI  Taketoshi MISHIMA  Taksu CHEON  

     
    PAPER

      Vol:
    E82-A No:9
      Page(s):
    1708-1713

    We propose a new method to construct a four parameter family of quantum-mechanical point interactions in one dimension, which is known as all possible self-adjoint extensions of the symmetric operator T=-Δ C0(R \{0}). It is achieved in the small distance limit of equally spaced three neighboring Dirac's δ potentials. The strength for each δ is appropriately renormalized according to the distance and it diverges, in general, in the small distance limit. The validity of our method is ensured by numerical calculations. In general cases except for usual δ, the wave function discontinuity appears around the interaction and one can observe such a tendency even at a finite distance level.

  • Looking Back 45 Years--Conversations with Von Neumann and Ulam-- and Also Looking Forward to the 21st Century

    Rudolf E. KALMAN  

     
    INVITED PAPER

      Vol:
    E82-A No:9
      Page(s):
    1686-1691

    A review of research, covering about 50 years, about random phenomena in nonlinear dynamical systems and the problems of modeling such phenomena using real (as contrasted to abstract, axiomatic) mathematics. Private views of the author concerning personalities and events.

  • Modular Approach for Solving Nonlinear Knapsack Problems

    Yuji NAKAGAWA  Akinori IWASAKI  

     
    PAPER

      Vol:
    E82-A No:9
      Page(s):
    1860-1864

    This paper develops an algorithm based on the Modular Approach to solve singly constrained separable discrete optimization problems (Nonlinear Knapsack Problems). The Modular Approach uses fathoming and integration techniques repeatedly. The fathoming reduces the decision space of variables. The integration reduces the number of variables in the problem by combining several variables into one variable. Computational experiments for "hard" test problems with up to 1000 variables are provided. Each variable has up to 1000 integer values.

  • CooPs: A Cooperative Process Planning System to Negotiate Process Change Requests

    Kagetomo GENJI  Katsuro INOUE  

     
    PAPER-Sofware System

      Vol:
    E82-D No:9
      Page(s):
    1261-1277

    In order to lead an ongoing software project to success, it is important to flexibly control its dynamically-changing software process. However, it is generally impossible not only to exactly pre-define the production process but also to prescribe the process change process (meta-process). To solve the problem, we have focused on communication between the project staff through which process change requests presented by individuals can be immediately shared, designed, verified, validated and implemented. This paper proposes a communication model which can represent a wide variety of communication states between the project manager and developers discussing how to implement process change requests. The communication model has been derived by investigating the sort of process change requests and, based on the model, we have implemented a cooperative process planning system (called CooPs). CooPs is a communication environment designed for software projects and supports information sharing for discussing the process change requests. By using CooPs, the software project can flexibly deal with not only expected change requests but also unexpected ones. To evaluate the applicability of the communication model and the capabilities of CooPs, we have conducted an experiment which is an application of CooPs to the ISPW6 example problem. This paper describes the concepts of CooPs, the system implementation, and the experiment.

  • On-Line Control of Discrete Event Systems with a Maximally Controllable and Observable Sublanguage

    Toshimitsu USHIO  

     
    PAPER-Graphs and Networks

      Vol:
    E82-A No:9
      Page(s):
    1965-1970

    Recently, many on-line control methods of partially observed discrete event systems(DES's) have been proposed. This paper proposes an algorithm for on-line control based on a supervisor under complete observation. It is shown that DES's controlled by the proposed on-line controller generate maximally controllable and observable sublanguages which include the supremal normal sublanguages. Moreover, computational complexity of the proposed algorithm is polynomial with respect to the numbers of the unobservable events and the state of the supervisor under complete observation.

  • A Scalable Pipelined Memory Architecture for Fast ATM Packet Switching

    Gab Joong JEONG  MoonKey LEE  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E82-A No:9
      Page(s):
    1937-1944

    This paper describes the design of a scalable pipelined memory buffer for a shared scalable buffer ATM switch. The memory architecture provides high speed and scalability, and eliminates the restriction of memory cycle time in a shared buffer ATM switch. It provides versatile performance in a shared buffer ATM switch using its scalability. The architecture consists of a 2-D array configuration of small memory banks. Increasing the array configuration enlarges the entire memory capacity. Maximum cycle time of a designed scalable memory is 4 ns. The designed memory is embedded in the prototype chip of a shared scalable buffer ATM switch with 4 4 configuration of 4160-bit SRAM memory banks. It is integrated in 0.6 µm double-metal single-poly CMOS technology.

  • Measurement-Based Real-Time Call Admission Control in ATM Networks

    Cheul SHIM  

     
    PAPER-Communication Networks and Services

      Vol:
    E82-B No:9
      Page(s):
    1371-1379

    The concept of a schedulable region (SR) was introduced to characterize the capacity of a multiplexer and provide a separation between call-level and cell-level phenomena. In this paper, we present a framework and algorithm for real-time estimation of the schedulable region. A major problem associated with online estimation is that the objects of measurement are not fixed in the presence of call arrivals and departures. The invariance property is exploited to carry out measurements in the presence of call arrivals and departures. By virtue of it, the equivalent bandwidth could be defined on the condition of the number of each traffic class call in progress. Another important thing we consider here is that the search algorithm to estimate the effective bandwidth should be chosen depending on the arrival statistics and QOS constraints. The algorithms presented here have been implemented on an ATM switch.

  • On the Takens-Bogdanov Bifurcation in the Chua's Equation

    Antonio ALGABA  Emilio FREIRE  Estanislao GAMERO  Alejandro J. RODRIGUEZ-LUIS  

     
    PAPER

      Vol:
    E82-A No:9
      Page(s):
    1722-1728

    The analysis of the Takens-Bogdanov bifurcation of the equilibrium at the origin in the Chua's equation with a cubic nonlinearity is carried out. The local analysis provides, in first approximation, different bifurcation sets, where the presence of several dynamical behaviours (including periodic, homoclinic and heteroclinic orbits) is predicted. The local results are used as a guide to apply the adequate numerical methods to obtain a global understanding of the bifurcation sets. The study of the normal form of the Takens-Bogdanov bifurcation shows the presence of a degenerate (codimension-three) situation, which is analyzed in both homoclinic and heteroclinic cases.

3681-3700hit(4570hit)