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8201-8220hit(21534hit)

  • Bandwidth and Gain Enhancement of Microstrip Patch Antennas Using Reflective Metasurface Open Access

    Sarawuth CHAIMOOL  Kwok L. CHUNG  Prayoot AKKARAEKTHALIN  

     
    INVITED PAPER

      Vol:
    E93-B No:10
      Page(s):
    2496-2503

    Bandwidth and gain enhancement of microstrip patch antennas (MPAs) is proposed using reflective metasurface (RMS) as a superstrate. Two different types of the RMS, namely- the double split-ring resonator (DSR) and double closed-ring resonator (DCR) are separately investigated. The two antenna prototypes were manufactured, measured and compared. The experimental results confirm that the RMS loaded MPAs achieve high-gain as well as bandwidth improvement. The desinged antenna using the RMS as a superstrate has a high-gain of over 9.0 dBi and a wide impedance bandwidth of over 13%. The RMS is also utilized to achieve a thin antenna with a cavity height of 6 mm, which is equivalent to λ/21 at the center frequency of 2.45 GHz. At the same time, the cross polarization level and front-to-back ratio of these antennas are also examined.

  • Improved Measurement Accuracy of a Laser Interferometer: Extended Kalman Filter Approach

    Wooram LEE  Dongkyun KIM  Kwanho YOU  

     
    LETTER-Systems and Control

      Vol:
    E93-A No:10
      Page(s):
    1820-1823

    In this paper a nonlinearity compensation algorithm based on the extended Kalman filter is proposed to improve the measurement accuracy of a heterodyne laser interferometer. The heterodyne laser interferometer is used for ultra-precision measurements such as those used in semiconductor manufacturing. However the periodical nonlinearity property caused by frequency-mixing restricts the accuracy of the nanometric measurements. In order to minimize the effect of the nonlinearity, the measurement process of the laser interferometer is modeled as a state equation and the extended Kalman filtering approach is applied to the process. The effectiveness of our proposed algorithm is demonstrated by comparing the results of the algorithm with experimental results for the laser system.

  • Achievable Rate of Adaptive Wireless Multicast with Antenna Diversity in Nakagami Fading Channels

    Jae Cheol PARK  Jin Soo WANG  Iickho SONG  Yun Hee KIM  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:10
      Page(s):
    2826-2829

    We derive the average achievable rate of an adaptive wireless multicast method with antenna diversity in Nakagami fading channels when the rate is selected by the minimum signal-to-noise ratio (SNR) of the multicast group. Based on the limiting distribution of the minimum SNR, we then derive an approximation to the average achievable rate, which provides accurate values easily in a wide range of channel parameters.

  • Optimization without Minimization Search: Constraint Satisfaction by Orthogonal Projection with Applications to Multiview Triangulation

    Kenichi KANATANI  Yasuyuki SUGAYA  Hirotaka NIITSUMA  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E93-D No:10
      Page(s):
    2836-2845

    We present an alternative approach to what we call the "standard optimization", which minimizes a cost function by searching a parameter space. Instead, our approach "projects" in the joint observation space onto the manifold defined by the "consistency constraint", which demands that any minimal subset of observations produce the same result. This approach avoids many difficulties encountered in the standard optimization. As typical examples, we apply it to line fitting and multiview triangulation. The latter produces a new algorithm far more efficient than existing methods. We also discuss the optimality of our approach.

  • Visual Knowledge Structure Reasoning with Intelligent Topic Map

    Huimin LU  Boqin FENG  Xi CHEN  

     
    PAPER-Artificial Intelligence, Data Mining

      Vol:
    E93-D No:10
      Page(s):
    2805-2812

    This paper presents a visual knowledge structure reasoning method using Intelligent Topic Map which extends the conventional Topic Map in structure and enhances its reasoning functions. Visual knowledge structure reasoning method integrates two types of knowledge reasoning: the knowledge logical relation reasoning and the knowledge structure reasoning. The knowledge logical relation reasoning implements knowledge consistency checking and the implicit associations reasoning between knowledge points. We propose a Knowledge Unit Circle Search strategy for the knowledge structure reasoning. It implements the semantic implication extension, the semantic relevant extension and the semantic class belonging confirmation. Moreover, the knowledge structure reasoning results are visualized using ITM Toolkit. A prototype system of visual knowledge structure reasoning has been implemented and applied to the massive knowledge organization, management and service for education.

  • Timing Offset Interference Canceller in Multi-Link Transmission for OFDM-Based Cellular Radio Communications

    Kenji HOSHINO  Atsushi NAGATE  Teruya FUJII  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E93-B No:10
      Page(s):
    2735-2741

    In next-generation mobile communications, it is important to improve the throughput of the cell edge as well as that of the whole cell. Multi-link transmission from two adjacent BSs has been studied for improving the throughput at the cell edge in OFDM-based cellular systems, which are major candidates for next-generation mobile communication systems. In multi-link transmission, an MS at a cell edge receives signals from both adjacent BSs by orthogonally multiplexing those signals in the frequency domain. Therefore, the cell-edge MS can utilize the frequency and power resources of both adjacent BSs, which improves the cell-edge throughput. However, when the received timing difference between the signals from both BSs exceeds the maximum permissible value, adjacent-channel interference is caused by the collapse of the orthogonality. In this paper, to resolve this issue, we propose a novel timing-offset interference canceller. To clarify the performance of the proposed canceller, this paper evaluates its performance with respect to the residual interference power and the BER by computer simulation.

  • Compact Circularly Polarized Microstrip Antennas Using EM Coupled Loop Resonators

    Junho CHOI  Seongmin PYO  Sang-Min HAN  Young-Sik KIM  

     
    LETTER-Antennas

      Vol:
    E93-B No:10
      Page(s):
    2658-2661

    In this letter, compact loop resonator type circular polarization (CP) antennas with a square ring and an X-shaped meander loop are presented. Both antennas are fed to a microstrip line with electromagnetic coupling. By adjusting the gap and length of a coupled microstrip line, the magnitude and phase conditions of two orthogonal modes for CP can be determined. The proposed antennas show good axial ratios and also good agreements between experimented and simulated results.

  • Further Results on Jury Test for Complex Polynomials

    Younseok CHOO  

     
    LETTER-Systems and Control

      Vol:
    E93-A No:10
      Page(s):
    1824-1826

    Recently a simple proof of Jury test for complex polynomials was given by the author. In this letter further extended results are presented. Another elementary proof of the Schur stability condition is provided. More importantly it is shown that the stability table can also be used to determine the root distribution of complex polynomials with respect to the unit circle in the complex plane.

  • Power Controlled Concurrent Transmissions in mmWave WPANs

    Yongsun KIM  Meejoung KIM  Wooyong LEE  Chul-Hee KANG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:10
      Page(s):
    2808-2811

    This letter considers power-controlled transmission from directional antennas in mmWave wireless personal area network (WPAN) systems. The attributes of these systems are studied; these include the number of concurrent transmissions and the power consumption with different system parameters, such as the antenna's beamwidth and radiating efficiency. Numerical results are presented to show that the power controlled transmission enables more concurrent transmissions than the non-power controlled transmission. The results also show that the number of concurrent transmissions increases as the beamwidth and the path loss component become smaller and the antenna's radiating efficiency increases. In addition, the power controlled system generally uses less power than the non-power controlled transmission set up; the overall analysis is verified by simulation.

  • The Design of a Total Ship Service Framework Based on a Ship Area Network

    Daekeun MOON  Kwangil LEE  Hagbae KIM  

     
    LETTER-Dependable Computing

      Vol:
    E93-D No:10
      Page(s):
    2858-2861

    The rapid growth of IT technology has enabled ship navigation and automation systems to gain better functionality and safety. However, they generally have their own proprietary structures and networks, which makes interfacing with and remote access to them difficult. In this paper, we propose a total ship service framework that includes a ship area network to integrate separate system networks with heterogeneity and dynamicity, and a ship-shore communication infrastructure to support a remote monitoring and maintenance service using satellite communications. Finally, we present some ship service systems to demonstrate the applicability of the proposed framework.

  • A Fast Architecture Exploration Method for High Throughput IEEE 802.11e MAC Implementation Using SystemC

    Sung-Rok YOON  Min Li HUANG  Sangho SEO  Hiroshi OCHI  Sin-Chong PARK  

     
    LETTER-Terrestrial Wireless Communication/Broadcasting Technologies

      Vol:
    E93-B No:10
      Page(s):
    2833-2836

    This paper presents a fast and systematic architecture exploration method that realizes an efficient IEEE 802.11e based hardware/software co-design Medium Access Control (MAC) system architecture, which can achieve near theoretical MAC throughput for burst data transmission while complying with strict channel access time requirements. Our design approach uses SystemC based Transaction Level Modeling (TLM) framework to integrate reconfigurable general purpose computing and communication resources into the application model for rapid evaluation of core parameters, system performance, and application specific optimizations. As a result, a MAC system architecture that achieves a simulated MAC throughput of more than 100 Mbps when transmitted at 260 Mbps of Physical Layer (PHY) data rate is obtained. This result is verified with X-X-IMPLEMENTATION on a Xilinx Field-Programmable Gate Array (FPGA) board.

  • Calibrating Coordinates of a Tabletop Display with a Reflex in Eye-Hand Coordination

    Makio ISHIHARA  Yukio ISHIHARA  

     
    LETTER-Human-computer Interaction

      Vol:
    E93-D No:10
      Page(s):
    2862-2865

    This manuscript introduces a pointing interface for a tabletop display with a reflex in eye-hand coordination. The reflex is a natural response to inconsistency between kinetic information of a mouse and visual feedback of the mouse cursor. The reflex yields information on which side the user sees the screen from, so that the screen coordinates are aligned with the user's position.

  • Accurate Human Detection by Appearance and Motion

    Shaopeng TANG  Satoshi GOTO  

     
    PAPER

      Vol:
    E93-D No:10
      Page(s):
    2728-2736

    In this paper, a human detection method is developed. An appearance based detector and a motion based detector are proposed respectively. A multi scale block histogram of template feature (MB-HOT) is used to detect human by the appearance. It integrates the gray value information and the gradient value information, and represents the relationship of three blocks. Experiment on INRIA dataset shows that this feature is more discriminative than other features, such as histogram of orientation gradient (HOG). A motion based feature is also proposed to capture the relative motion of human body. This feature is calculated in optical flow domain and experimental result in our dataset shows that this feature outperforms other motion based features. The detection responses obtained by two features are combined to reduce the false detection. Graphic process unit (GPU) based implementation is proposed to accelerate the calculation of two features, and make it suitable for real time applications.

  • A Semi-Supervised Approach to Perceived Age Prediction from Face Images

    Kazuya UEKI  Masashi SUGIYAMA  Yasuyuki IHARA  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E93-D No:10
      Page(s):
    2875-2878

    We address the problem of perceived age estimation from face images, and propose a new semi-supervised approach involving two novel aspects. The first novelty is an efficient active learning strategy for reducing the cost of labeling face samples. Given a large number of unlabeled face samples, we reveal the cluster structure of the data and propose to label cluster-representative samples for covering as many clusters as possible. This simple sampling strategy allows us to boost the performance of a manifold-based semi-supervised learning method only with a relatively small number of labeled samples. The second contribution is to take the heterogeneous characteristics of human age perception into account. It is rare to misjudge the age of a 5-year-old child as 15 years old, but the age of a 35-year-old person is often misjudged as 45 years old. Thus, magnitude of the error is different depending on subjects' age. We carried out a large-scale questionnaire survey for quantifying human age perception characteristics, and propose to utilize the quantified characteristics in the framework of weighted regression. Consequently, our proposed method is expressed in the form of weighted least-squares with a manifold regularizer, which is scalable to massive datasets. Through real-world age estimation experiments, we demonstrate the usefulness of the proposed method.

  • A Low-Profile Dual-Polarized Directional Antenna for Enhancing Channel Capacity in Indoor MIMO Systems

    Daisuke UCHIDA  Hiroyuki ARAI  Yuki INOUE  Keizo CHO  

     
    PAPER-Antennas

      Vol:
    E93-B No:10
      Page(s):
    2570-2577

    The use of directional antenna and polarization diversity techniques has been reported to achieve good MIMO performance. Low-profile, small structures are required to configure the MIMO antenna with these techniques. First, we assume downlink transmission in indoor MIMO systems and present the design guidelines for the radiation pattern to obtain large channel capacity by the ray-tracing method. We then propose a uni-directional, dual-polarized MIMO antenna with a thickness of 0.24λ based on the design guidelines. The proposed antenna consists of dipole antennas mounted horizontally to the ground plane and cavity backed slot antennas for vertical polarization. We apply the proposed antenna to 2 2 MIMO transmission and demonstrate the effectiveness of channel capacity enhancement in an actual environment. The improvement factor is revealed to be +16.2% with place averaged value compared to sleeve antenna configuration.

  • Metamaterial-Based Microstrip Antenna Using Slot-Embedded Ground Plane for Bandwidth Improvements

    Seongmin PYO  Min-Jae LEE  Young-Sik KIM  

     
    LETTER-Antennas and Propagation

      Vol:
    E93-B No:10
      Page(s):
    2784-2786

    In this letter, a new design of a metamaterial-based microstrip antenna is presented using triangular slots embedded on the ground plane to enhance the impedance bandwidth. To improve the impedance bandwidth of the proposed antenna, two resonant mode frequencies are closely allocated using the slotted ground without changing the radiator element. The impedance bandwidth of VSWR < 2.5 is measured at 2.43 GHz (37.6%) centered on 6.46 GHz, from 5.24 GHz to 7.67 GHz in good agreements with the simulated results.

  • Reconstruction of a Dielectric Cylinder with the Use of the T-Matrix and the Singular Value Decomposition

    Kenichi ISHIDA  

     
    PAPER-Electromagnetic Analysis

      Vol:
    E93-B No:10
      Page(s):
    2595-2600

    An algorithm is formulated for reconstructing a dielectric cylinder with the use of the T-matrix and the singular value decomposition (SVD) and is discussed through numerical examples under noisy conditions. The algorithm consists of two stages. At the first stage the measured data of scattered waves is transformed into the T-matrix. At the second stage we reconstruct the cylinder from the T-matrix. The singular value decomposition is applied in order to separate the radiating and the nonradiating currents, and the radiating current is directly obtained from the T-matrix. The nonradiating current and the object are reconstructed by decreasing a residual error of the current in the least square approximation, where linear equations are solved repeatedly. Some techniques are used in order to reduce the calculation time and to reduce the effects of noise. Numerical examples show us that the presented approach is simple and numerically feasible, and enables us to reconstruct a large object in a short time.

  • Electrical Properties of Ba0.5Sr0.5Ta2O6 Thin Film Fabricated by Sol-Gel Method

    Li LU  Masahiro ECHIZEN  Takashi NISHIDA  Kiyoshi UCHIYAMA  Yukiharu URAOKA  

     
    PAPER

      Vol:
    E93-C No:10
      Page(s):
    1511-1515

    Ba0.5Sr0.5Ta2O6 (BSTA) thin film was successfully fabricated on a Pt/SiO2/TiO2/Si substrate using the Sol-Gel method. Fundamental electrical properties of the BSTA thin film were investigated using metal-insulator-metal (MIM) structure. No diffusion of ions, from the thin film or the substrate, is observed because of the using of MIM structure. The Root Mean Square roughness of 1.04 nm shows that thin film grew well on the substrate. The BSTA thin film shows a much higher dielectric constant of about 130 than conventional gate insulators and high-k materials that are currently used in Thin Film Transistors. Low leakage current density of about 10-8 A/cm2 was obtained at an applied electric field of 500 kV/cm. Schottky emission is the dominant conduction mechanism at applied electric fields lower than 500 kV/cm and Fowler-Nordheim tunneling is the dominant conduction mechanism at higher applied electric fields. The Schottky barrier height between the Pt electrode and the Ba0.5Sr0.5Ta2O6 thin film was estimated to be 0.75 eV.

  • Privacy Preserving Frequency Mining in 2-Part Fully Distributed Setting

    The Dung LUONG  Tu Bao HO  

     
    PAPER

      Vol:
    E93-D No:10
      Page(s):
    2702-2708

    Recently, privacy preservation has become one of the key issues in data mining. In many data mining applications, computing frequencies of values or tuples of values in a data set is a fundamental operation repeatedly used. Within the context of privacy preserving data mining, several privacy preserving frequency mining solutions have been proposed. These solutions are crucial steps in many privacy preserving data mining tasks. Each solution was provided for a particular distributed data scenario. In this paper, we consider privacy preserving frequency mining in a so-called 2-part fully distributed setting. In this scenario, the dataset is distributed across a large number of users in which each record is owned by two different users, one user only knows the values for a subset of attributes, while the other knows the values for the remaining attributes. A miner aims to compute the frequencies of values or tuples of values while preserving each user's privacy. Some solutions based on randomization techniques can address this problem, but suffer from the tradeoff between privacy and accuracy. We develop a cryptographic protocol for privacy preserving frequency mining, which ensures each user's privacy without loss of accuracy. The experimental results show that our protocol is efficient as well.

  • Three-Dimensional Electromagnetic Scattering Analysis Using Constrained Interpolation Profile Method

    Jerdvisanop CHAKAROTHAI  Qiang CHEN  Kunio SAWAYA  

     
    PAPER-Electromagnetic Analysis

      Vol:
    E93-B No:10
      Page(s):
    2619-2628

    A characteristic-based constrained interpolation profile (CIP) method for solving three-dimensional, time-dependent Maxwell's equations is successfully developed. It is utilized to solve one-dimensional wave equations in the formulation of the Maxwell's equations. Calculation procedure of the CIP method for three-dimensional scattering analysis is described in details. Update equations for boundary conditions of a perfectly conducting (PEC) interface and a dielectric interface are formulated and obtained in explicit forms. Numerical analyses of electromagnetic scatterings of PEC sphere, dielectric sphere and PEC cube are performed and the scattering coefficient is calculated and compared with the Mie's analytic results. As a result, the scattering coefficients show good agreement with the Mie's results, which demonstrates the validity of the CIP method and the formulated update equations. It is also shown that the phase of the scattering coefficients determined by the CIP method are slightly more accurate than that of the FDTD method.

8201-8220hit(21534hit)