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[Keyword] SI(16314hit)

4241-4260hit(16314hit)

  • A Web Page Segmentation Approach Using Visual Semantics

    Jun ZENG  Brendan FLANAGAN  Sachio HIROKAWA  Eisuke ITO  

     
    PAPER-Data Engineering, Web Information Systems

      Vol:
    E97-D No:2
      Page(s):
    223-230

    Web page segmentation has a variety of benefits and potential web applications. Early techniques of web page segmentation are mainly based on machine learning algorithms and rule-based heuristics, which cannot be used for large-scale page segmentation. In this paper, we propose a formulated page segmentation method using visual semantics. Instead of analyzing the visual cues of web pages, this method utilizes three measures to formulate the visual semantics: layout tree is used to recognize the visual similar blocks; seam degree is used to describe how neatly the blocks are arranged; content similarity is used to describe the content coherent degree between blocks. A comparison experiment was done using the VIPS algorithm as a baseline. Experiment results show that the proposed method can divide a Web page into appropriate semantic segments.

  • A New Preprocessing Method for Efficient Construction of Decision Diagrams

    S. R. MALATHI  P. SAKTHIVEL  

     
    PAPER-Algorithms and Data Structures

      Vol:
    E97-A No:2
      Page(s):
    624-631

    Many discrete functions are often compactly represented by Decision Diagrams (DD). The main problem in the construction of decision diagrams is the space and time requirements. While constructing a decision diagram the memory requirement may grow exponentially with the function. Also, large numbers of temporary nodes are created while constructing the decision diagram for a function. Here the problem of reducing the number of temporary nodes is addressed with respect to the PLA specification format of a function, where the function is represented using a set of cubes. Usually a DD is constructed by recursively processing the input cubes in the PLA specification. The DD, representing a sub function, is specified by a single cube. This DD is merged with a master DD, which represents the entire previously processed cubes. Thus the master DD is constructed recursively, until all the cubes in the input cube set are processed. In this paper, an efficient method is proposed, which reorders and also partitions the cube set into unequal number of cubes per subset, in such a way that, the number of temporary nodes created and the number of logical operations done, during the merging of cubes with the master DD are reduced. This results in the reduction of space and time required for the construction of DDs to a remarkable extent.

  • Advanced QRD-M Detection with Iterative Scheme in the MIMO-OFDM System

    Hwan-Jun CHOI  Hyoung-Kyu SONG  

     
    LETTER-Information Network

      Vol:
    E97-D No:2
      Page(s):
    340-343

    In this letter, advanced QRD-M detection using iterative scheme is proposed. This scheme has a higher diversity degree than conventional QRD-M detection. According to the simulation results, the performance of proposed QRD-M detection is 0.5dB to 5.5dB better than the performance of conventional QRD-M detection and average iteration time is approximately 1 in the value of M = 1, 2, 3. Therefore, the proposed QRD-M detection has better performance than conventional QRD-M detection, particularly in a high SNR environment and low modulation order.

  • Discrete Abstraction for a Class of Stochastic Hybrid Systems Based on Bounded Bisimulation

    Koichi KOBAYASHI  Yasuhito FUKUI  Kunihiko HIRAISHI  

     
    PAPER

      Vol:
    E97-A No:2
      Page(s):
    459-467

    A stochastic hybrid system can express complex dynamical systems such as biological systems and communication networks, but computation for analysis and control is frequently difficult. In this paper, for a class of stochastic hybrid systems, a discrete abstraction method in which a given system is transformed into a finite-state system is proposed based on the notion of bounded bisimulation. In the existing discrete abstraction method based on bisimulation, a computational procedure is not in general terminated. In the proposed method, only the behavior for the finite time interval is expressed as a finite-state system, and termination is guaranteed. Furthermore, analysis of genetic toggle switches is also discussed as an application.

  • Weighted Hard Combination for Cooperative Spectrum Sensing under Noise Uncertainty

    Ruyuan ZHANG  Yafeng ZHAN  Yukui PEI  Jianhua LU  

     
    PAPER

      Vol:
    E97-B No:2
      Page(s):
    275-282

    Cooperative spectrum sensing is an effective approach that utilizes spatial diversity gain to improve detection performance. Most studies assume that the background noise is exactly known. However, this is not realistic because of noise uncertainty which will significantly degrade the performance. A novel weighted hard combination algorithm with two thresholds is proposed by dividing the whole range of the local test statistic into three regions called the presence, uncertainty and absence regions, instead of the conventional two regions. The final decision is made by weighted combination at the common receiver. The key innovation is the full utilization of the information contained in the uncertainty region. It is worth pointing out that the weight coefficient and the local target false alarm probability, which determines the two thresholds, are also optimized to minimize the total error rate. Numerical results show this algorithm can significantly improve the detection performance, and is more robust to noise uncertainty than the existing algorithms. Furthermore, the performance of this algorithm is not sensitive to the local target false alarm probability at low SNR. Under sufficiently high SNR condition, this algorithm reduces to the improved one-out-of-N rule. As noise uncertainty is unavoidable, this algorithm is highly practical.

  • Ghost Reduction for Multiple Angle Sensors Based on Tracking Process by Dual Hypotheses

    Kosuke MARUYAMA  Hiroshi KAMEDA  

     
    PAPER-Sensing

      Vol:
    E97-B No:2
      Page(s):
    504-511

    A ghost reduction algorithm for multiple angle sensors tracking objects under dual hypotheses is proposed. When multiple sensors and multiple objects exist on the same plane, the conventional method is unable to distinguish the real objects and ghosts from all possible pairs of measurement angle vectors. In order to resolve the issue stated above, the proposed algorithm utilizes tracking process considering dual hypotheses of real objects and ghosts behaviors. The proposed algorithm predicts dynamics of all the intersections of measurement angle vector pairs with the hypotheses of real objects and ghosts. Each hypothesis is evaluated by the residuals between prediction data and intersection. The appropriate hypothesis is extracted trough several data sampling. Representative simulation results demonstrate the effectiveness of the proposed algorithm.

  • PWG: Progressive Weight-Growth Algorithm for LDPC Codes

    Xiangxue LI  Qingji ZHENG  Haifeng QIAN  Dong ZHENG  Kefei CHEN  

     
    LETTER-Coding Theory

      Vol:
    E97-A No:2
      Page(s):
    685-689

    Given specified parameters, the number of check nodes, the expected girth and the variable node degrees, the Progressive Weight-Growth (PWG) algorithm is proposed to generate high rate low-density parity-check (LDPC) codes. Based on the theoretic foundation that is to investigate the girth impact by adding/removing variable nodes and edges of the Tanner graph, the PWG progressively increases column weights of the parity check matrix without violating the constraints defined by the given parameters. The analysis of the computational complexity and the simulation of code performance show that the LDPC codes by the PWG provide better or comparable performance in comparison with LDPC codes by some well-known methods (e.g., Mackay's random constructions, the PEG algorithm, and the bit-filling algorithm).

  • Bias Free Adaptive Notch Filter Based on Fourier Sine Series

    Kazuki SHIOGAI  Naoto SASAOKA  Masaki KOBAYASHI  Isao NAKANISHI  James OKELLO  Yoshio ITOH  

     
    PAPER-Digital Signal Processing

      Vol:
    E97-A No:2
      Page(s):
    557-564

    Conventional adaptive notch filter based on an infinite impulse response (IIR) filter is well known. However, this kind of adaptive notch filter has a problem of stability due to its adaptive IIR filter. In addition, tap coefficients of this notch filter converge to solutions with bias error. In order to solve these problems, an adaptive notch filter using Fourier sine series (ANFF) is proposed. The ANFF is stable because an adaptive IIR filter is not used as an all-pass filter. Further, the proposed adaptive notch filter is robust enough to overcome effects of a disturbance signal, due to a structure of the notch filter based on an exponential filter and line symmetry of auto correlation.

  • An Iterative Reweighted Least Squares Algorithm with Finite Series Approximation for a Sparse Signal Recovery

    Kazunori URUMA  Katsumi KONISHI  Tomohiro TAKAHASHI  Toshihiro FURUKAWA  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E97-D No:2
      Page(s):
    319-322

    This letter deals with a sparse signal recovery problem and proposes a new algorithm based on the iterative reweighted least squares (IRLS) algorithm. We assume that the non-zero values of a sparse signal is always greater than a given constant and modify the IRLS algorithm to satisfy this assumption. Numerical results show that the proposed algorithm recovers a sparse vector efficiently.

  • Iterative Method for Inverse Nonlinear Image Processing

    Zihan YU  Kiichi URAHAMA  

     
    LETTER-Image

      Vol:
    E97-A No:2
      Page(s):
    719-721

    We present an iterative method for inverse transform of nonlinear image processing. Its convergence is verified for image enhancement by an online software. We also show its application to amplification of the opacity in foggy or underwater images.

  • Accurate Permittivity Estimation Method for 3-Dimensional Dielectric Object with FDTD-Based Waveform Correction

    Ryunosuke SOUMA  Shouhei KIDERA  Tetsuo KIRIMOTO  

     
    BRIEF PAPER-Electromagnetic Theory

      Vol:
    E97-C No:2
      Page(s):
    123-127

    Ultra-wideband pulse radar exhibits high range resolution, and excellent capability in penetrating dielectric media. With that, it has great potential as an innovative non-destructive inspection technique for objects such as human body or concrete walls. For suitability in such applications, we have already proposed an accurate permittivity estimation method for a 2-dimensional dielectric object of arbitrarily shape and clear boundary. In this method, the propagation path estimation inside the dielectric object is calculated, based on the geometrical optics (GO) approximation, where the dielectric boundary points and its normal vectors are directly reproduced by the range point migration (RPM) method. In addition, to compensate for the estimation error incurred using the GO approximation, a waveform compensation scheme employing the finite-difference time domain (FDTD) method was incorporated, where an initial guess of the relative permittivity and dielectric boundary are employed for data regeneration. This study introduces the 3-dimensional extension of the above permittivity estimation method, aimed at practical uses, where only the transmissive data are effectively extracted, based on quantitative criteria that considers the spatial relationship between antenna locations and the dielectric object position. Results from a numerical simulation verify that our proposed method accomplishes accurate permittivity estimations even for 3-dimensional dielectric medium of wavelength size.

  • Speech/Music Classification Enhancement for 3GPP2 SMV Codec Based on Deep Belief Networks

    Ji-Hyun SONG  Hong-Sub AN  Sangmin LEE  

     
    LETTER-Speech and Hearing

      Vol:
    E97-A No:2
      Page(s):
    661-664

    In this paper, we propose a robust speech/music classification algorithm to improve the performance of speech/music classification in the selectable mode vocoder (SMV) of 3GPP2 using deep belief networks (DBNs), which is a powerful hierarchical generative model for feature extraction and can determine the underlying discriminative characteristic of the extracted features. The six feature vectors selected from the relevant parameters of the SMV are applied to the visible layer in the proposed DBN-based method. The performance of the proposed algorithm is evaluated using the detection accuracy and error probability of speech and music for various music genres. The proposed algorithm yields better results when compared with the original SMV method and support vector machine (SVM) based method.

  • Computer Power Supply Efficiency Improvement by Power Consumption Prediction Procedure Using Performance Counters

    Shinichi KAWAGUCHI  Toshiaki YACHI  

     
    PAPER-Energy in Electronics Communications

      Vol:
    E97-B No:2
      Page(s):
    408-415

    As the use of information technology (IT) is explosively spreading, reducing the power consumption of IT devices such as servers has become an important social challenge. Nevertheless, while the efficiency of the power supply modules integrated into computers has recently seen significant improvements, their overall efficiency generally depends on load rates. This is especially true under low power load conditions, where it is known that efficiency decreases drastically. Recently, power-saving techniques that work by controlling the power module configuration under low power load conditions have been considered. Based on such techniques, further efficiency improvements can be expected by an adaptive efficiency controls which interlocks the real-time data processing load status with the power supply configuration control. In this study, the performance counters built into the processor of a computer are used to predict power load variations and an equation that predicts the power consumption levels is defined. In a server application experiment utilizing prototype computer hardware and regression analysis, it is validated that the equation could precisely predict processor power consumption. The evaluation shows that significant power supply efficiency improvements could be achieved especially for light load condition. The dependency of the efficiency improvement and operation period is investigated and preferable time scale of the adaptive control is proposed.

  • Cell Clustering Algorithm in Uplink Network MIMO Systems with Individual SINR Constraints

    Sang-Uk PARK  Jung-Hyun PARK  Dong-Jo PARK  

     
    LETTER-Communication Theory and Signals

      Vol:
    E97-A No:2
      Page(s):
    698-703

    This letter deals with a new cell clustering problem subject to signal-to-interference-plus-noise-ratio (SINR) constraints in uplink network MIMO systems, where multiple base stations (BSs) cooperate for joint processing as forming a cluster. We first prove that the SINRs of users in a certain cluster always increase monotonically as the cluster size increases when the receiver filter that maximizes the SINR is used. Using this result, we propose an efficient clustering algorithm to minimize the maximum number of cooperative BSs in a cluster. Simulation results show that the maximum number of cooperative BSs minimized by the proposed method is close to that minimized by the exhaustive search and the proposed scheme outperforms the conventional one in terms of the outage probability.

  • Reduction Operators Based on Behavioral Inheritance for Timed Petri Nets

    Ichiro TOYOSHIMA  Shota NAKANO  Shingo YAMAGUCHI  

     
    LETTER

      Vol:
    E97-A No:2
      Page(s):
    484-489

    In this paper, we proposed reduction operators of timed Petri net for efficient model checking. Timed Petri nets are used widely for modeling and analyzing systems which include time concept. Analysis of the system can be done comprehensively with model checking, but there is a state-space explosion problem. Therefore, previous researchers proposed reduction methods and translation methods to timed automata to perform efficient model checking. However, there is no reduction method which consider observability and there is a trade-off between the amount of description and the size of state space. In this paper, first, we have defined a concept of timed behavioral inheritance. Next, we have proposed reduction operators of timed Petri nets based on timed behavioral inheritance. Then, we have applied our proposed operators to an artificial timed Petri net. Moreover, the results show that the reduction operators which consider observability can reduce the size of state space of the original timed Petri nets within the experiment.

  • Parallel Cyclostationarity-Exploiting Algorithm for Energy-Efficient Spectrum Sensing

    Arthur D.D. LIMA  Carlos A. BARROS  Luiz Felipe Q. SILVEIRA  Samuel XAVIER-DE-SOUZA  Carlos A. VALDERRAMA  

     
    PAPER

      Vol:
    E97-B No:2
      Page(s):
    326-333

    The evolution of wireless communication systems leads to Dynamic Spectrum Allocation for Cognitive Radio, which requires reliable spectrum sensing techniques. Among the spectrum sensing methods proposed in the literature, those that exploit cyclostationary characteristics of radio signals are particularly suitable for communication environments with low signal-to-noise ratios, or with non-stationary noise. However, such methods have high computational complexity that directly raises the power consumption of devices which often have very stringent low-power requirements. We propose a strategy for cyclostationary spectrum sensing with reduced energy consumption. This strategy is based on the principle that p processors working at slower frequencies consume less power than a single processor for the same execution time. We devise a strict relation between the energy savings and common parallel system metrics. The results of simulations show that our strategy promises very significant savings in actual devices.

  • Erasable Photograph Tagging: A Mobile Application Framework Employing Owner's Voice

    Zhenfei ZHAO  Hao LUO  Hua ZHONG  Bian YANG  Zhe-Ming LU  

     
    LETTER-Speech and Hearing

      Vol:
    E97-D No:2
      Page(s):
    370-372

    This letter proposes a mobile application framework named erasable photograph tagging (EPT) for photograph annotation and fast retrieval. The smartphone owner's voice is employed as tags and hidden in the host photograph without an extra feature database aided for retrieval. These digitized tags can be erased anytime with no distortion remaining in the recovered photograph.

  • Closed Form Expressions of Balanced Realizations of Second-Order Analog Filters

    Shunsuke YAMAKI  Masahide ABE  Masayuki KAWAMATA  

     
    PAPER-Digital Signal Processing

      Vol:
    E97-A No:2
      Page(s):
    565-571

    This paper derives the balanced realizations of second-order analog filters directly from the transfer function. Second-order analog filters are categorized into the following three cases: complex conjugate poles, distinct real poles, and multiple real poles. For each case, simple formulas are derived for the synthesis of the balanced realizations of second-order analog filters. As a result, we obtain closed form expressions of the balanced realizations of second-order analog filters.

  • Fast and Accurate Architecture Exploration for High Performance and Low Energy VLIW Data-Path

    Ittetsu TANIGUCHI  Kohei AOKI  Hiroyuki TOMIYAMA  Praveen RAGHAVAN  Francky CATTHOOR  Masahiro FUKUI  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E97-A No:2
      Page(s):
    606-615

    A fast and accurate architecture exploration for high performance and low energy VLIW data-path is proposed. The main contribution is a method to find Pareto optimal FU structures, i.e., the optimal number of FUs and the best instruction assignment for each FU. The proposed architecture exploration method is based on GA and enables the effective exploration of vast solution space. Experimental results showed that proposed method was able to achieve fast and accurate architecture exploration. For most cases, the estimation error was less than 1%.

  • A Partially-Corporate Feed Double-Layer Waveguide Slot Array with the Sub-Arrays also Fed in Alternating-Phases

    Miao ZHANG  Jiro HIROKAWA  Makoto ANDO  

     
    PAPER-Antennas and Propagation

      Vol:
    E97-B No:2
      Page(s):
    469-475

    As a promising lamination-loss-free fabrication technique, diffusion bonding of etched thin metal plates is used to realize double-layer waveguide slot antennas. Alternating-phase feed is adopted in this paper to reduce the number of laminated plates to simplify fabrication as well as to reduce cost. A 20 × 20-element double-layer waveguide slot antenna with a bottom partially-corporate feed circuit is designed for 39GHz band operation as an example. The adjacent radiating waveguides as well as the 2 × 2 sub-arrays fed in an alternating-phase manner eliminate the need for complete electrical contact in the top layer. However, the feed circuit in the bottom layer has to be completely diffusion-bonded. These two layers are simply assembled by screws. An antenna laminated by only diffusion bonding is also fabricated and evaluated for comparison. The comparison proved that the simply fabricated antenna is comparable in performance to the fully diffusion-bonded one.

4241-4260hit(16314hit)