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7881-7900hit(20498hit)

  • Fast Self-Expansion of Sensing Coverage in Autonomous Mobile Sensor Networks

    Youn-Hee HAN  Heon-Jong LEE  Sung-Gi MIN  

     
    LETTER-Network

      Vol:
    E93-B No:11
      Page(s):
    3148-3151

    Random scattering of sensors may cause some location not to be covered. In such a case, it is useful to make use of mobile sensors that can move to eliminate the coverage holes. Wang et al [1]. proposed self-deployment schemes of mobile sensors by using Voronoi polygon. However, some coverage holes still remain after the execution of the schemes. We propose a new self-deployment scheme using the centroid (geometric center) of each sensor's Voronoi polygon as the moving target position. The performance evaluation shows that the proposed scheme achieves better results than the existing schemes in terms of fast coverage expansion.

  • Estimation of Distribution Algorithm Incorporating Switching

    Kenji TSUCHIE  Yoshiko HANADA  Seiji MIYOSHI  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E93-D No:11
      Page(s):
    3108-3111

    We propose an "estimation of distribution algorithm" incorporating switching. The algorithm enables switching from the standard estimation of distribution algorithm (EDA) to the genetic algorithm (GA), or vice versa, on the basis of switching criteria. The algorithm shows better performance than GA and EDA in deceptive problems.

  • Multiple-Input Multiple-Output Overlap-Save Frequency-Domain Decision-Feedback Equalization for Single-Carrier Systems in Time-Varying Environments

    Ang FENG  Qinye YIN  Xue FENG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:11
      Page(s):
    3203-3206

    In this letter, we propose a novel frequency-domain equalization (FDE) scheme for single-carrier multiple-input multiple-output (MIMO) systems over time-varying channels. Based on frequency-domain decision-feedback equalization (FD-DFE), we design a feedforward filter with constraint such that the equalization can be easily realized segment-by-segment with the help of the overlap-save (OLS) method. Since the segment length and block length can be designed independently, our proposal sets relatively short segment length to obtain good performance in time-varying environments, and very long block length to achieve high spectral efficiency. Furthermore, we present two scenarios in the design of filters for MIMO systems.

  • Measurement of Complex Permittivity for Liquid Materials Using the Open-Ended Cut-Off Waveguide Reflection Method

    Kouji SHIBATA  

     
    PAPER-Microwaves, Millimeter-Waves

      Vol:
    E93-C No:11
      Page(s):
    1621-1629

    Various studies of specific absorption rates (SARs) using liquid phantoms imitating human body tissues have been widely carried out in electromagnetic compatibility (EMC) research fields. In order to establish accurate SARs for measurement, a faithful mockup of human body tissue is needed. Therefore, knowledge of the accurate measurement of sample materials with high permittivity and high loss is very important. In this study, the complex permittivity of tap water, ethanol, methanol and isopropanol is measured by the open-ended cut-off circular waveguide reflection method. The effectiveness of the method presented here of measuring a liquid phantom with high-permittivity and high-loss is also confirmed by comparing the measured results with the results obtained by the TM010 circular cavity resonator method. At this time, the effects on the input impedance under variations of the insertion length and termination conditions were studied. Then the complex permittivity of tap water, ethanol, methanol and isopropanol was measured at frequencies ranging from 0.5 to 3.0 GHz using the measurement procedure above. As a result, we confirmed the frequency characteristics of the complex permittivity for a wide variety of high-loss liquid materials.

  • Design and Analysis on Macro Diversity Scheme for Broadcast Services in Mobile Cellular Systems

    Yang LIU  Hui ZHAO  Yunchuan YANG  Wenbo WANG  Kan ZHENG  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E93-B No:11
      Page(s):
    3113-3120

    Recently, broadcast services are introduced in cellular networks and macro diversity is an effective way to combat fading. In this paper, we propose a kind of distributed space-time block codes (STBCs) for macro diversity which is constructed from the total antennas of multiple cooperating base stations, and all the antennas form an equivalent multiple input multiple output (MIMO) system. This code is termed High-Dimension-Full-Rate-Quasi-Orthogonal STBC (HDFR-QOSTBC) which can be characterized as: (1) It can be applied with any number of transmit antennas especially when the number of transmit antennas is large; (2) The code is with full transmit rate of one; (3) The Maximum Likelihood (ML) decoding complexity of this code is controllable and limited to Nt/2-symbol-decodable for total Nt transmit antennas. Then, we completely analyze the structure of the equivalent channel for the kind of codes and reveal a property that the eigenvectors of the equivalent channel are constant and independent from the channel realization, and this characteristic can be exploited for a new transmission structure with single-symbol linear decoder. Furthermore, we analyze different macro diversity schemes and give a performance comparison. The simulation results show that the proposed scheme is practical for the broadcast systems with significant performance improvement comparing with soft-combination and cyclic delay diversity (CDD) methods.

  • Estimation of the Effects in the Experimental Design Using Fourier Transforms

    Yoshifumi UKITA  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    LETTER-Information Theory

      Vol:
    E93-A No:11
      Page(s):
    2077-2082

    We propose that the model in experimental design be expressed in terms of an orthonormal system. Then, we can easily estimate the effects using Fourier transforms. We also provide the theorems with respect to the sum of squares needed in analysis of variance. Using these theorems, it is clear that we can execute the analysis of variance in this model.

  • Spectrophotometer Calibration by a Double Integrating Sphere Reference Light Source and Display Panel Measurement Using Dark Sphere Open Access

    Tatsuhiko MATSUMOTO  Shigeo KUBOTA  Tsutomu SHIMURA  Shuichi HAGA  Takehiro NAKATSUE  Junichi OHSAKO  

     
    INVITED PAPER

      Vol:
    E93-C No:11
      Page(s):
    1590-1594

    We succeeded to develop a reference light source in the range of very low luminance using a double integrating sphere system, and calibrated a commercial spectrophotometer below 110-5 cd/m2 levels, which is 1/100 lower than the specified limit for measurement. And we improved measurements in the ultra low luminance range of displays using the calibrated commercial spectrophotometer and a dark sphere to suppress the influence of the surround.

  • Implementation of a WSN-Based Structural Health Monitoring Architecture Using 3D and AR Mode

    Bonhyun KOO  Taeshik SHON  

     
    LETTER

      Vol:
    E93-B No:11
      Page(s):
    2963-2966

    Recently wireless sensor networks (WSN) has risen as one of the advanced candidate technologies in order to provide more efficient structure health monitoring (SHM) solution in construction sites. In this paper, we proposed WSN monitoring framework in building sites based on 3D visualization and Augmented Reality (AR) in mobile devices. The proposed system applies 3D visualization and AR technology to camera-enabled mobile devices in WSN environment in order to gather much more information than before. Based on the proposed system, we made an experiment to validate the effectiveness of 3D and AR mode using collected data in IEEE 802.15.4-based WSN.

  • A Quantitative Evaluation Method for Luminance Non-uniformity of a Large LED Backlight Open Access

    Yuko MASAKURA  Tohru TAMURA  Kunihiko NAGAMINE  Satoshi TOMIOKA  Mitsunori UEDA  Yoshihide SHIMPUKU  

     
    INVITED PAPER

      Vol:
    E93-C No:11
      Page(s):
    1564-1571

    This report describes a quantification method for luminance non-uniformity of a large LED backlight. In experiments described herein, participants subjectively evaluated artificial indistinct Mura images that simulated luminance non-uniformity of an LED backlight. We measured the luminance distribution of the Mura images. Then, the measured luminance distribution was converted into S-CIELAB, in which anisotropic properties of the spatial frequency response of human vision were considered. Subsequently, some indexes for the quantification model were extracted. We conducted multiple regression analyses using the subjective evaluation value and the index values obtained from measured luminance of Mura image. We proposed a quantification model consisting of four indexes: high and low luminance area, number of Mura edges, sum of Mura edge areas, and maximum luminance difference.

  • Closed-Loop Quasi-Orthogonal Space-Time Block Codes with Power Scaling and Low-Rate Feedback Information

    Hoojin LEE  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:11
      Page(s):
    3211-3214

    Recently, novel full-diversity full-rate quasi-orthogonal space-time block codes (QSTBCs) with power scaling and double-symbol maximum likelihood (ML) decoding was proposed. Specifically, the codes can achieve full-diversity through linearly combining two adequately power scaled orthogonal space-time block codes (OSTBCs). In this letter, we derive expressions for mutual information and post-processing signal-to-noise ratio (SNR) for a system with four transmit antennas. By exploiting these formulas, we propose three transmit antenna grouping (TAG) methods for a closed-loop system with low-rate feedback information. The TAG methods make it possible to provide an excellent error-rate performance even with a low-complexity zero-forcing (ZF) detection, especially in spatially correlated fading channels.

  • An Efficient Algorithm for Point Set Registration Using Analytic Differential Approach

    Ching-Chi CHEN  Wei-Yen HSU  Shih-Hsuan CHIU  Yung-Nien SUN  

     
    PAPER-Biological Engineering

      Vol:
    E93-D No:11
      Page(s):
    3100-3107

    Image registration is an important topic in medical image analysis. It is usually used in 2D mosaics to construct the whole image of a biological specimen or in 3D reconstruction to build up the structure of an examined specimen from a series of microscopic images. Nevertheless, owing to a variety of factors, including microscopic optics, mechanisms, sensors, and manipulation, there may be great differences between the acquired image slices even if they are adjacent. The common differences include the chromatic aberration as well as the geometry discrepancy that is caused by cuts, tears, folds, and deformation. They usually make the registration problem a difficult challenge to achieve. In this paper, we propose an efficient registration method, which consists of a feature-based registration approach based on analytic robust point matching (ARPM) and a refinement procedure of the feature-based Levenberg-Marquardt algorithm (FLM), to automatically reconstruct 3D vessels of the rat brains from a series of microscopic images. The registration algorithm could speedily evaluate the spatial correspondence and geometric transformation between two point sets with different sizes. In addition, to achieve subpixel accuracy, an FLM method is used to refine the registered results. Due to the nonlinear characteristic of FLM method, it converges much faster than most other methods. We evaluate the performance of proposed method by comparing it with well-known thin-plate spline robust point matching (TPS-RPM) algorithm. The results indicate that the ARPM algorithm together with the FLM method is not only a robust but efficient method in image registration.

  • A Novel Measured Function for MCDM Problem Based on Interval-Valued Intuitionistic Fuzzy Sets

    Kuo-Chen HUNG  Yuan-Cheng TSAI  Kuo-Ping LIN  Peterson JULIAN  

     
    PAPER-Office Information Systems, e-Business Modeling

      Vol:
    E93-D No:11
      Page(s):
    3059-3065

    Several papers have presented measured function to handle multi-criteria fuzzy decision-making problems based on interval-valued intuitionistic fuzzy sets. However, in some cases, the proposed function cannot give sufficient information about alternatives. Consequently, in this paper, we will overcome previous insufficient problem and provide a novel accuracy function to measure the degree of the interval-valued intuitionistic fuzzy information. And a practical example has been provided to demonstrate our proposed approach. In addition, to make computing and ranking results easier and to increase the recruiting productivity, a computer-based interface system has been developed for decision makers to make decisions more efficiently.

  • Stacked Rectangular Microstrip Antenna with a Shorting Plate and a Helical Pin for Triple Band Operation in ITS

    Takafumi FUJIMOTO  

     
    PAPER-Antennas and Propagation

      Vol:
    E93-B No:11
      Page(s):
    3058-3065

    A stacked rectangular microstrip antenna with a shorting plate and a helical pin is proposed as a car antenna for triple band operation in ITS. The proposed antenna operates as a conventional stacked microstrip antenna at the highest frequency band. At the middle and the lowest frequency bands, the antenna radiates at low elevation angles from the helical pin and the shorting plate. In this paper, as an example of triple band antennas in the ITS, an antenna is designed that supports PHS, VICS and ETC. The proposed antennas have the proper radiation pattern for each application and are small in size.

  • Heuristic Designs of SAD Algorithm for a Platform-Based Vision System

    JunSeong KIM  Jongsu YI  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E93-D No:11
      Page(s):
    3140-3143

    Vision sensors provide rich sources of information, but sensing images and processing them in real time would be a challenging task. This paper introduces a vision system using SoCBase platform and presents heuristic designs of SAD correlation algorithm as a component of the vision system. Simulation results show that the vision system is suitable for real-time applications and that the heuristic designs of SAD algorithm are worth utilizing since they save a considerable amount of space with little sacrificing in quality.

  • Multichannel Random Access Protocol with Capture Effect for Cellular Relaying Networks

    Sunghyun CHO  Young-Ho JUNG  Cheolwoo YOU  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E93-B No:11
      Page(s):
    3093-3101

    This paper proposes a stabilized multichannel random access protocol based on slotted ALOHA for relay deployed cellular networks. To ensure the stability of random access, the proposed protocol dynamically controls the number of random access channels in a BS and a RS and the retransmission probability of the random access packets under heavy load conditions. A mathematical formula is also developed that derives an optimal partition ratio of the shared random access channels between a base station and a relay station without and with capture effect. Numerical results show that the proposed protocol can guarantee the required utilization and delay even in high offered load, which otherwise can cause bistable problem of slotted ALOHA.

  • NP-Hard and k-EXPSPACE-Hard Cast Puzzles

    Chuzo IWAMOTO  Kento SASAKI  Kenji NISHIO  Kenichi MORITA  

     
    PAPER-Fundamentals of Information Systems

      Vol:
    E93-D No:11
      Page(s):
    2995-3004

    A disentanglement puzzle consists of mechanically interlinked pieces, and the puzzle is solved by disentangling one piece from another set of pieces. A cast puzzle is a type of disentanglement puzzle, where each piece is a zinc die-casting alloy. In this paper, we consider the generalized cast puzzle problem whose input is the layout of a finite number of pieces (polyhedrons) in the 3-dimensional Euclidean space. For every integer k ≥ 0, we present a polynomial-time transformation from an arbitrary k-exponential-space Turing machine M and its input x to a cast puzzle c1 of size k-exponential in |x| such that M accepts x if and only if c1 is solvable. Here, the layout of c1 is encoded as a string of length polynomial (even if c1 has size k-exponential). Therefore, the cast puzzle problem of size k-exponential is k-EXPSPACE-hard for every integer k ≥ 0. We also present a polynomial-time transformation from an arbitrary instance f of the SAT problem to a cast puzzle c2 such that f is satisfiable if and only if c2 is solvable.

  • New Classes of Optimal Variable-Weight Optical Orthogonal Codes Based on Cyclic Difference Families

    Dianhua WU  Pingzhi FAN  Xun WANG  Minquan CHENG  

     
    PAPER-Sequences

      Vol:
    E93-A No:11
      Page(s):
    2232-2238

    Variable-weight optical orthogonal code (OOC) was introduced by G-C Yang for multimedia optical CDMA systems with multiple quality of service (QoS) requirement. In this paper, a construction for optimal (υ, {3,4}, 1, {s/(s+1), 1/(s+1)})-OOCs is given. For s=2, it is proved that for each prime υ≡ 1(mod 24), there exists a (υ, {3,4}, 1, {2/3, 1/3})-OOC. A recursive construction for cyclic difference family is also presented. By using these constructions, a number of new infinite classes of optimal (υ, {3,4}, 1, Q)-OOCs for Q = {1/2, 1/2} and {2/3, 1/3} are constructed.

  • Towards a Fairness Multimedia Transmission Using Layered-Based Multicast Protocol

    Heru SUKOCO  Yoshiaki HORI  Hendrawan   Kouichi SAKURAI  

     
    PAPER

      Vol:
    E93-D No:11
      Page(s):
    2953-2961

    The distribution of streaming multicast and real time audio/video applications in the Internet has been quickly increased in the Internet. Commonly, these applications rarely use congestion control and do not fairly share provided network capacity with TCP-based applications such as HTTP, FTP and emails. Therefore, Internet communities will be threatened by the increase of non-TCP-based applications that likely cause a significant increase of traffics congestion and starvation. This paper proposes a set of mechanisms, such as providing various data rates, background traffics, and various scenarios, to act friendly with TCP when sending multicast traffics. By using 8 scenarios of simulations, we use 6 layered multicast transmissions with background traffic Pareto with the shape factor 1.5 to evaluate performance metrics such as throughput, delay/latency, jitter, TCP friendliness, packet loss ratio, and convergence time. Our study shows that non TCP traffics behave fairly and respectful of the co-existent TCP-based applications that run on shared link transmissions even with background traffic. Another result shows that the simulation has low values on throughput, vary in jitter (0-10 ms), and packet loss ratio > 3%. It was also difficult to reach convergence time quickly when involving only non TCP traffics.

  • Error-Resilient 3-D Wavelet Video Coding with Duplicated Lowest Sub-Band Coefficients and Two-Step Error Concealment Method

    Sunmi KIM  Hirokazu TANAKA  Takahiro OGAWA  Miki HASEYAMA  

     
    PAPER

      Vol:
    E93-A No:11
      Page(s):
    2173-2183

    In this paper, we propose a two-step error concealment algorithm based on an error resilient three-dimensional discrete wavelet transform (3-D DWT) video coding scheme. The proposed scheme consists of an error-resilient encoder duplicating the lowest sub-band bit-streams for dispersive grouped frames and an error concealment decoder. The error concealment method of this decoder is decomposed of two steps, the first step is replacement of erroneous coefficients in the lowest sub-band by the duplicated coefficients, and the second step is interpolation of the missing wavelet coefficients by minimum mean square error (MMSE) estimation. The proposed scheme can achieve robust transmission over unreliable channels. Experimental results provide performance comparisons in terms of peak signal-to-noise ratio (PSNR) and demonstrate increased performances compared to state-of-the-art error concealment schemes.

  • Recent Advances in Single-Carrier Frequency-Domain Equalization and Distributed Antenna Network

    Fumiyuki ADACHI  Kazuki TAKEDA  Tatsunori OBARA  Tetsuya YAMAMOTO  Hiroki MATSUDA  

     
    INVITED PAPER

      Vol:
    E93-A No:11
      Page(s):
    2201-2211

    Broadband wireless technology that enables a variety of gigabit-per-second class data services is a requirement in future wireless communication systems. Broadband wireless channels become extremely frequency-selective and cause severe inter-symbol interference (ISI). Furthermore, the average received signal power changes in a random manner because of the shadowing and distance-dependant path losses resulted from the movement of a mobile terminal (MT). Accordingly, the transmission performance severely degrades. To overcome the performance degradation, two most promising approaches are the frequency-domain equalization (FDE) and distributed antenna network (DAN). The former takes advantage of channel frequency-selectivity to obtain the frequency-diversity gain. In DAN, a group of distributed antennas serve each user to mitigate the negative impact of shadowing and path losses. This article will introduce the recent advances in FDE and DAN for the broadband single-carrier (SC) transmissions.

7881-7900hit(20498hit)