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[Keyword] SC(4570hit)

1681-1700hit(4570hit)

  • An Algorithm for Inferring K Optimum Transformations of XML Document from Update Script to DTD

    Nobutaka SUZUKI  

     
    PAPER-Data Engineering, Web Information Systems

      Vol:
    E93-D No:8
      Page(s):
    2198-2212

    DTDs are continuously updated according to changes in the real world. Let t be an XML document valid against a DTD D, and suppose that D is updated by an update script s. In general, we cannot uniquely "infer" a transformation of t from s, i.e., we cannot uniquely determine the elements in t that should be deleted and/or the positions in t that new elements should be inserted into. In this paper, we consider inferring K optimum transformations of t from s so that a user finds the most desirable transformation more easily. We first show that the problem of inferring K optimum transformations of an XML document from an update script is NP-hard even if K = 1. Then, assuming that an update script is of length one, we show an algorithm for solving the problem, which runs in time polynomial of |D|, |t|, and K.

  • A -68.5 dB IM3 Low-Voltage CMOS Transconductor with Wide Tuning Range

    Tien-Yu LO  Chung-Chih HUNG  Chi-Hsiang LO  

     
    LETTER-Analog Signal Processing

      Vol:
    E93-A No:8
      Page(s):
    1556-1559

    A CMOS transconductor for multi-mode application is presented. The transconductor includes a voltage-to-current converter and a current multiplier. Voltage-to-current conversion employs linear region MOS transistors, and the conversion features high linearity over a wide input swing range. The current multiplier, which operates in the weak inversion region, provides a wide transconductance tuning range without degrading the linearity. The transconductor was designed and fabricated in the TSMC 0.18-µm CMOS process. The results show the transconductance tuning ratio of 23 and the IM3 performance of -68.5 dB.

  • Receive Diversity Combining Techniques for SC-FDMA-Based Cooperative Relays

    Kyung-Soo WOO  Yeong-Jun KIM  Hyun-Il YOO  Jaekwon KIM  Sangboh YUN  Yong-Soo CHO  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:8
      Page(s):
    2195-2198

    In this letter, two receive diversity combining techniques are proposed for cooperative relay systems based on single-carrier frequency division multiple access (SC-FDMA) when relay station (RS) transmits the received signals from multiple mobile stations (MSs) together using one large size discrete Fourier transform (DFT). A simplified-MRC (S-MRC) technique performs diversity combining in the time-domain by using the estimated channel weights and initial estimates obtained by the SC-FDMA signal detector. An interference rejection-MRC (IR-MRC) technique performs diversity combining in the frequency-domain by adjusting the DFT spreading size at the receiver. It is shown by computer simulation that the proposed receive combining techniques achieve a significant diversity gain over the conventional techniques.

  • An Unassisted Low-Voltage-Trigger ESD Protection Structure in a 0.18-µm CMOS Process without Extra Process Cost

    Bing LI  Yi SHAN  

     
    PAPER-Integrated Electronics

      Vol:
    E93-C No:8
      Page(s):
    1359-1364

    In order to quickly discharge the electrostatic discharge (ESD) energy, an unassisted low-voltage-trigger ESD protection structure is proposed in this work. Under transmission line pulsing (TLP) stress, the trigger voltage, turn-on speed and second breakdown current can be obviously improved, as compared with the traditional protection structure. Moreover there is no need to add any extra mask or do any process modification for the new structure. The proposed structure has been verified in foundry's 0.18-µm CMOS process.

  • Impact and Use of the Asymmetric Property in Bi-directional Cooperative Relaying under Asymmetric Traffic Conditions

    Takaaki SAEKI  Koji YAMAMOTO  Hidekazu MURATA  Susumu YOSHIDA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E93-B No:8
      Page(s):
    2126-2134

    Cooperative relaying (CR) is a promising technique to provide spatial diversity by combining multiple signals from source and relay stations. In the present paper, the impact and use of the asymmetric property in bi-directional CR under asymmetric traffic conditions are discussed assuming that CR involves one communication pair and one relay station in a time division duplex (TDD) system. The asymmetric property means that the average communication quality differs for each transmission direction because of the difference in signal power between the combined signals for each direction. First, numerical results show the asymmetric property of bi-directional CR. Next, in order to evaluate the impact of the asymmetric property, the optimal relay position and resource allocation are compared to those in simple multi-hop relaying, which does not have the asymmetric property. Numerical results show that, in order to maximize the overall quality of bi-directional communication, the optimal relay position in CR depends on the offered traffic ratio, which is defined as the traffic ratio of each transmission direction, while the offered traffic ratio does not affect the optimal relay position in multi-hop relaying. Finally, the asymmetric property is used to enhance the overall quality. Specifically, a high overall quality can be achieved by, for example, opportunistically switching to the transmission direction with higher quality. Under asymmetric traffic conditions, weighted proportionally fair scheduling (WPFS), which is proposed in the context of downlink scheduling in a cellular network, is applied to transmission direction switching. Numerical results reveal that WPFS provides a high overall quality and that the quality ratio is similar to the offered traffic ratio.

  • Simulation Modeling of SAM Fuzzy Logic Controllers

    Hae Young LEE  Seung-Min PARK  Tae Ho CHO  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E93-D No:7
      Page(s):
    1984-1986

    This paper presents an approach to implementing simulation models for SAM fuzzy controllers without the use of external components. The approach represents a fuzzy controller as a composition of simple simulation models which involve only basic operations.

  • Fast Polar and Spherical Fourier Descriptors for Feature Extraction

    Zhuo YANG  Sei-ichiro KAMATA  

     
    PAPER

      Vol:
    E93-D No:7
      Page(s):
    1708-1715

    Polar Fourier Descriptor(PFD) and Spherical Fourier Descriptor(SFD) are rotation invariant feature descriptors for two dimensional(2D) and three dimensional(3D) image retrieval and pattern recognition tasks. They are demonstrated to show superiorities compared with other methods on describing rotation invariant features of 2D and 3D images. However in order to increase the computation speed, fast computation method is needed especially for machine vision applications like realtime systems, limited computing environments and large image databases. This paper presents fast computation method for PFD and SFD that are deduced based on mathematical properties of trigonometric functions and associated Legendre polynomials. Proposed fast PFD and SFD are 8 and 16 times faster than direct calculation that significantly boost computation process. Furthermore, the proposed methods are also compact for memory requirements for storing PFD and SFD basis in lookup tables. The experimental results on both synthetic and real data are given to illustrate the efficiency of the proposed method.

  • Lightwave Transceivers for Optical Access Systems

    Junichi NAKAGAWA  Masamichi NOGAMI  Masaki NODA  Naoki SUZUKI  Satoshi YOSHIMA  Hitoyuki TAGAMI  

     
    INVITED PAPER

      Vol:
    E93-C No:7
      Page(s):
    1158-1164

    10G-EPON systems have attracted a great deal of attention as a way of exceeding to realize over 10 Gb/s for optical subscriber networking. Rapid burst-mode transmitting/receiving techniques are the key technologies enabling the burst-mode upstream transmission of 10G-EPON systems. In this paper, we have developed a OLT burst-mode 3R receiver incorporating a burst-mode AGC optical receiver and an 82.5 GS/s over-sampling burst-mode CDR and a ONU burst-mode transmitter with high launch power DFB-LD of 1.27 µm wavelength to fully compliant with IEEE802.3av 10G-EPON PR30 standards. The transmitting characteristics of a fast LD turn-on/off time of less than 6ns and a high launch power of more than +8.0 dBm, and the receiving characteristics of receiver sensitivity of -30.1 dBm and the upstream power budget of 38.1 dB are successfully achieved.

  • The 8th Harmonic Push-Push Oscillator in V Band

    Kengo KAWASAKI  Takayuki TANAKA  Masayoshi AIKAWA  

     
    PAPER

      Vol:
    E93-C No:7
      Page(s):
    1000-1006

    In this paper, the 8th harmonic Push-Push oscillator is successfully presented. The Push-Push principle and the excellent harmonic coherency in a microwave resonator are effectively utilized. The proposed oscillator consists of two sub-circuits, a microstrip ring resonator and an output circuit. The concept of the simplified structure harmonic oscillator (SSHO) is adopted in the proposed oscillator. The microstrip ring resonator plays two roles of the common resonator and the power combiner circuit. This kind of Push-Push oscillator has practical advantages of the easy circuit design due to the simple circuit configuration and the miniaturization of the circuit size. Using the Push-Push principle and the effective circuit configuration of the output circuit, the desired 8th harmonic signal is effectively enhanced. This Push-Push oscillator achieves good millimeter-wave oscillation in V band using inexpensively available X band HEMTs. The estimated output power of -6 dBm at the frequency of 51 GHz is obtained with the phase noise of -93 dBc/Hz at the offset frequency of 1 MHz.

  • Constant Modulus Algorithm with Reduced Complexity Employing DFT Domain Fast Filtering

    Yoon Gi YANG  Chang Su LEE  Soo Mi YANG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:7
      Page(s):
    1974-1979

    In this paper, a novel CMA (constant modulus algorithm) algorithm employing fast convolution in the DFT (discrete Fourier transform) domain is proposed. We propose a non-linear adaptation algorithm that minimizes CMA cost function in the DFT domain. The proposed algorithm is completely new one as compared to the recently introduced similar DFT domain CMA algorithm in that, the original CMA cost function has not been changed to develop DFT domain algorithm, resulting improved convergence properties. Using the proposed approach, we can reduce the number of multiplications to O(Nlog2 N), whereas the conventional CMA has the computation order of O(N2). Simulation results show that the proposed algorithm provides a comparable performance to the conventional CMA.

  • Design of High-Performance Analog Circuits Using Wideband gm-Enhanced MOS Composite Transistors

    Yang TIAN  Pak Kwong CHAN  

     
    PAPER-Electronic Circuits

      Vol:
    E93-C No:7
      Page(s):
    1199-1208

    In this paper, we present a new composite transistor circuit design technique that provides superior performance enhancement to analog circuits. By adding a composite transistor to the cascode-compensated amplifier, it has achieved a 102 dB DC gain, and a 37.6 MHz unity gain bandwidth while driving a 2 nF heavy capacitive load at a single 1.8 V supply. In the comparison of power-bandwidth and power-speed efficiencies on figures of merit, it offers significantly high values with respect to the reported state-of-the-art works. By employing the composite transistor in a linear regulator powered by a 3.3 V supply to generate a 1.8 V output voltage, it has shown fast recovery response at various load current transients, having a 1% settling time of 0.1 µS for a 50 mA or 100 mA step, while a 1% settling time of 0.36 µS for a maximum 735 mA step under a capacitive load of 10 µF with a 1 Ω ESR resistor. The simulated load regulation is 0.035% and line regulation is 0.488%. Comparing its results with other state-of-art LDO reported results, it also validates the significant enhanced performance of the proposed composite-transistor-based design in terms of speed, current driving capability and stability against changes in environmental parameters. All the proposed designs are simulated using chartered semiconductor (CSM) 1.8 V/3.3 V 0.18 µm CMOS triple-well process technology with thin/thick oxide options and BSIM3 model parameters.

  • Extraction Method of Scallop Area in Gravel Seabed Images for Fishery Investigation

    Koichiro ENOMOTO  Masashi TODA  Yasuhiro KUWAHARA  

     
    PAPER

      Vol:
    E93-D No:7
      Page(s):
    1754-1760

    The quantity and state of fishery resources must be known so that they can be sustained. The fish culture industry is also planning to investigate resources. The results of investigations are used to estimate the catch size, times fish are caught, and future stocks. We have developed a method for extracting scallop areas from gravel seabed images to assess fish resources and also developed an automatic system that measures their quantities, sizes, and states. Japanese scallop farms for fisheries are found on gravel and sand seabeds. The seabed images are used for fishery investigations, which are absolutely necessary to visually estimate, and help us avoid using the acoustic survey. However, there is no automatic technology to measure the quantities, sizes, and states of resources, and so the current investigation technique is the manual measurement by experts. There are varied problems in automating technique. The photography environments have a high degree of noise, including large differences in lighting. Gravel, sand, clay, and debris are also included in the images. In the gravel field, we can see scallop features, such as colors, striped patterns, and fan-like shapes. This paper describes the features of our image extracting method, presents the results, and evaluates its effectiveness.

  • High-Speed Computation of the Kleene Star in Max-Plus Algebraic System Using a Cell Broadband Engine

    Hiroyuki GOTO  

     
    PAPER-Fundamentals of Information Systems

      Vol:
    E93-D No:7
      Page(s):
    1798-1806

    This research addresses a high-speed computation method for the Kleene star of the weighted adjacency matrix in a max-plus algebraic system. We focus on systems whose precedence constraints are represented by a directed acyclic graph and implement it on a Cell Broadband EngineTM (CBE) processor. Since the resulting matrix gives the longest travel times between two adjacent nodes, it is often utilized in scheduling problem solvers for a class of discrete event systems. This research, in particular, attempts to achieve a speedup by using two approaches: parallelization and SIMDization (Single Instruction, Multiple Data), both of which can be accomplished by a CBE processor. The former refers to a parallel computation using multiple cores, while the latter is a method whereby multiple elements are computed by a single instruction. Using the implementation on a Sony PlayStation 3TM equipped with a CBE processor, we found that the SIMDization is effective regardless of the system's size and the number of processor cores used. We also found that the scalability of using multiple cores is remarkable especially for systems with a large number of nodes. In a numerical experiment where the number of nodes is 2000, we achieved a speedup of 20 times compared with the method without the above techniques.

  • BioEncoding: A Reliable Tokenless Cancelable Biometrics Scheme for Protecting IrisCodes

    Osama OUDA  Norimichi TSUMURA  Toshiya NAKAGUCHI  

     
    PAPER-Information Network

      Vol:
    E93-D No:7
      Page(s):
    1878-1888

    Despite their usability advantages over traditional authentication systems, biometrics-based authentication systems suffer from inherent privacy violation and non-revocability issues. In order to address these issues, the concept of cancelable biometrics was introduced as a means of generating multiple, revocable, and noninvertible identities from true biometric templates. Apart from BioHashing, which is a two-factor cancelable biometrics technique based on mixing a set of tokenized user-specific random numbers with biometric features, cancelable biometrics techniques usually cannot preserve the recognition accuracy achieved using the unprotected biometric systems. However, as the employed token can be lost, shared, or stolen, BioHashing suffers from the same issues associated with token-based authentication systems. In this paper, a reliable tokenless cancelable biometrics scheme, referred to as BioEncoding, for protecting IrisCodes is presented. Unlike BioHashing, BioEncoding can be used as a one-factor authentication scheme that relies only on sole IrisCodes. A unique noninvertible compact bit-string, referred to as BioCode, is randomly derived from a true IrisCode. Rather than the true IrisCode, the derived BioCode can be used efficiently to verify the user identity without degrading the recognition accuracy obtained using original IrisCodes. Additionally, BioEncoding satisfies all the requirements of the cancelable biometrics construct. The performance of BioEncoding is compared with the performance of BioHashing in the stolen-token scenario and the experimental results show the superiority of the proposed method over BioHashing-based techniques.

  • Tile-Image Merging and Delivering for Virtual Camera Services on Tiled-Display for Real-Time Remote Collaboration

    Giseok CHOE  Jongho NANG  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E93-D No:7
      Page(s):
    1944-1956

    The tiled-display system has been used as a Computer Supported Cooperative Work (CSCW) environment, in which multiple local (and/or remote) participants cooperate using some shared applications whose outputs are displayed on a large-scale and high-resolution tiled-display, which is controlled by a cluster of PC's, one PC per display. In order to make the collaboration effective, each remote participant should be aware of all CSCW activities on the titled display system in real-time. This paper presents a capturing and delivering mechanism of all activities on titled-display system to remote participants in real-time. In the proposed mechanism, the screen images of all PC's are periodically captured and delivered to the Merging Server that maintains separate buffers to store the captured images from the PCs. The mechanism selects one tile image from each buffer, merges the images to make a screen shot of the whole tiled-display, clips a Region of Interest (ROI), compresses and streams it to remote participants in real-time. A technical challenge in the proposed mechanism is how to select a set of tile images, one from each buffer, for merging so that the tile images displayed at the same time on the tiled-display can be properly merged together. This paper presents three selection algorithms; a sequential selection algorithm, a capturing time based algorithm, and a capturing time and visual consistency based algorithm. It also proposes a mechanism of providing several virtual cameras on tiled-display system to remote participants by concurrently clipping several different ROI's from the same merged tiled-display images, and delivering them after compressing with video encoders requested by the remote participants. By interactively changing and resizing his/her own ROI, a remote participant can check the activities on the tiled-display effectively. Experiments on a 32 tiled-display system show that the proposed merging algorithm can build a tiled-display image stream synchronously, and the ROI-based clipping and delivering mechanism can provide individual views on the tiled-display system to multiple remote participants in real-time.

  • Analysis of Microstrip Line with Bends Using Fourier Transform and Mode-Matching Technique

    Hyun Ho PARK  

     
    PAPER-PCB and Circuit Design for EMI Control

      Vol:
    E93-B No:7
      Page(s):
    1731-1738

    In this paper, the transmission and reflection properties of the microstrip line with bends are investigated using the Fourier transform and a mode-matching technique. Based on the waveguide model, the microstrip bends are modeled as the rectangular waveguides with perfect electric conducting top and bottom walls and perfect magnetic conducting side walls. Analytical closed-form expressions for transmission and reflection coefficients are developed using the residue calculus. To verify the proposed method, numerical computations are performed for comparison with 3D full-wave simulations and measurements. A quarter-wavelength transmission line scheme is also proposed to improve the signal integrity of double bend discontinuity.

  • Experimental Quasi-Microwave Whole-Body Averaged SAR Estimation Method Using Cylindrical-External Field Scanning

    Yoshifumi KAWAMURA  Takashi HIKAGE  Toshio NOJIMA  

     
    PAPER-Biological Effects and Safety

      Vol:
    E93-B No:7
      Page(s):
    1826-1833

    The aim of this study is to develop a new whole-body averaged specific absorption rate (SAR) estimation method based on the external-cylindrical field scanning technique. This technique is adopted with the goal of simplifying the dosimetry estimation of human phantoms that have different postures or sizes. An experimental scaled model system is constructed. In order to examine the validity of the proposed method for realistic human models, we discuss the pros and cons of measurements and numerical analyses based on the finite-difference time-domain (FDTD) method. We consider the anatomical European human phantoms and plane-wave in the 2 GHz mobile phone frequency band. The measured whole-body averaged SAR results obtained by the proposed method are compared with the results of the FDTD analyses.

  • Estimation of Potential Gradient from Discharge Current through Hand-Held Metal Piece from Charged Human Body

    Yoshinori TAKA  Osamu FUJIWARA  

     
    PAPER-ESD and Transients

      Vol:
    E93-B No:7
      Page(s):
    1797-1800

    Electrostatic discharge (ESD) events due to metal objects electrified with low voltages give a fatal electromagnetic interference to high-tech information equipment. In order to elucidate the mechanism, with a 6-GHz digital oscilloscope, we previously measured the discharge current due to collision of a hand-held metal piece from a charged human body, and gave a current calculation model. In this study, based on the calculation model, a method was presented for deriving a gap potential gradient from the measured discharge current. Measurements of the discharge currents were made for charge voltages from 200 V to 1000 V. The corresponding potential gradients were estimated, which were validated in comparison with an empirical formula based on the Paschen's law together with other researcher's experimental results.

  • Packet Scheduling Mechanism to Improve Quality of Short Flows and Low-Rate Flows

    Kenji YOKOTA  Takuya ASAKA  Tatsuro TAKAHASHI  

     
    PAPER-Internet

      Vol:
    E93-B No:7
      Page(s):
    1890-1896

    In recent years elephant flows are increasing by expansion of peer-to-peer (P2P) applications on the Internet. As a result, bandwidth is occupied by specific users triggering unfair resource allocation. The main packet-scheduling mechanism currently employed is first-in first-out (FIFO) where the available bandwidth of short flows is limited by elephant flows. Least attained service (LAS), which decides transfer priority of packets by the total amount of transferred data in all flows, was proposed to solve this problem. However, routers with LAS limit flows with large amount of transferred data even if they are low-rate. Therefore, it is necessary to improve the quality of low-rate flows with long holding times such as voice over Internet protocol (VoIP) applications. This paper proposes rate-based priority control (RBPC), which calculates the flow rate and control the priority by using it. Our proposed method can transfer short flows and low-rate flows in advance. Moreover, its fair performance is shown through simulations.

  • Static Estimation of the Meteorological Visibility Distance in Night Fog with Imagery

    Romain GALLEN  Nicolas HAUTIERE  Eric DUMONT  

     
    PAPER

      Vol:
    E93-D No:7
      Page(s):
    1780-1787

    In this article, we propose a new way to estimate fog extinction at night with a camera. We also propose a method for the classification of fog depending on the forward scattering. We show that a characterization of fog based on the atmospheric extinction parameter only is not sufficient, specifically in the perspective of adaptive lighting for road safety. This method has been validated on synthetic images generated with a semi Monte-Carlo ray tracing software dedicated to fog simulation as well as with experiments in a fog chamber, we present the results and discuss the method, its potential applications and its limits.

1681-1700hit(4570hit)