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1521-1540hit(5900hit)

  • Novel Improvements on the Fuzzy-Rough QuickReduct Algorithm

    Javad Rahimipour ANARAKI  Mahdi EFTEKHARI  Chang Wook AHN  

     
    LETTER-Pattern Recognition

      Pubricized:
    2014/10/21
      Vol:
    E98-D No:2
      Page(s):
    453-456

    Feature Selection (FS) is widely used to resolve the problem of selecting a subset of information-rich features; Fuzzy-Rough QuickReduct (FRQR) is one of the most successful FS methods. This paper presents two variants of the FRQR algorithm in order to improve its performance: 1) Combining Fuzzy-Rough Dependency Degree with Correlation-based FS merit to deal with a dilemma situation in feature subset selection and 2) Hybridizing the newly proposed method with the threshold based FRQR. The effectiveness of the proposed approaches are proven over sixteen UCI datasets; smaller subsets of features and higher classification accuracies are achieved.

  • Evaluation of a PAH/PSS Layer-by-Layer Deposited Film Using a Quartz-Crystal-Microbalance and Surface-Plasmon-Resonance Hybrid Sensor

    Keisuke KAWACHI  Kazunari SHINBO  Yasuo OHDAIRA  Akira BABA  Keizo KATO  Futao KANEKO  

     
    BRIEF PAPER

      Vol:
    E98-C No:2
      Page(s):
    136-138

    A quartz-crystal-microbalance (QCM) and surface-plasmon-resonance (SPR) hybrid sensor was prepared, and the depositions of polymer electrolytes layer-by-layer (LbL) films were observed in situ. The estimated thicknesses obtained from the QCM method were different from those obtained from the SPR method. This was estimated to be caused by film swelling and water contained in the film.

  • Optimization of Learning Time for Learning-Assisted Rendezvous Channel in Cognitive Radio System

    Osamu TAKYU  Takayuki YAMAKITA  Takeo FUJII  Mai OHTA  Fumihito SASAMORI  Shiro HANDA  

     
    PAPER-Terrestrial Wireless Communication/Broadcasting Technologies

      Vol:
    E98-B No:2
      Page(s):
    360-369

    This paper derives the optimal learning time for the learning-assisted rendezvous channel. One problem with the dynamic spectrum access system of cognitive radio is access channel mismatch between two wireless terminals. In the learning-assisted rendezvous channel, before exchanging packets for link connection, the rate of channel occupancy by the other system is estimated within the learning time; it is referred to as the channel occupancy rate (COR). High speed packet exchange is made possible by selecting a low COR channel. However, the optimal learning time and the impact of COR estimation errors have not been clarified yet. This paper analyzes the time to rendezvous channel (TTR), where TTR is the time needed to complete the rendezvous with a certain probability. The results indicate that the learning time and TTR have a concave relationship which means that the optimal learning time can be determined.

  • A Scattering Field Expression by Dielectric Gratings Using Circularly Poarized Waves

    Hideaki WAKABAYASHI  Masamitsu ASAI  Jiro YAMAKITA  

     
    BRIEF PAPER-Electromagnetic Theory

      Vol:
    E98-C No:2
      Page(s):
    162-165

    In the scattering problem of dielectric gratings in conical mounting, we have considered and formulated scattering fields using transverse electric (TE) and transverse magnetic (TM) waves. This paper formulates scattering fields by superpositions of right-circularly (RC) and left-circularly (LC) polarized waves through the matrix eigenvalue method.

  • Cuckoo Search Algorithm for Job Scheduling in Cloud Systems

    Supacheep AMTADE  Toshiyuki MIYAMOTO  

     
    LETTER

      Vol:
    E98-A No:2
      Page(s):
    645-649

    A cloud system is defined as a large scale computer system that contains running high performance computers and responds to a large number of incoming tasks over the Internet. In this paper, we consider the problem to schedule computational jobs efficiently regarding system resource constraint and introduce a cuckoo search (CS) algorithm. Experimental results show that CS outperforms the genetic algorithm in terms of fitness value.

  • Sum Rate Analysis of MU-MISO Systems with ZF Beamforming over Composite Fading Channels

    Ou ZHAO  Hidekazu MURATA  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    558-568

    The performance of multiuser multiple-input single-output (MU-MISO) systems is not only affected by small-scale multipath fading but also by large-scale fading (i.e., shadowing) and path loss. In this paper, we concentrate on the sum rate distribution of MU-MISO systems employing linear zero-forcing beamforming, accounting for both multipath fading and shadowing effects, as well as spatial correlation at the transmit and receiver sides. In particular, we consider the classical spatially correlated lognormal model and propose closed-form bounds on the distribution of the achievable sum rates in MU-MISO systems. With the help of these bounds, we derive a relationship between the interuser distance and sum rate corresponding to 10% of the cumulative distribution function under different environmental conditions. A practical conclusion from our results based on the considered system is that the effect of spatially correlated shadowing can be considered to be independent when the interuser distance is approximately five times the shadowing correlation distance. Furthermore, a detailed analysis of the effects of composite channel attenuation consisting of multipath fading and shadowing is also provided.

  • Distributed Synchronization for Message-Passing Based Embedded Multiprocessors

    Hao XIAO  Ning WU  Fen GE  Guanyu ZHU  Lei ZHOU  

     
    LETTER-Architecture

      Vol:
    E98-D No:2
      Page(s):
    272-275

    This paper presents a synchronization mechanism to effectively implement the lock and barrier protocols in a decentralized manner through explicit message passing. In the proposed solution, a simple and efficient synchronization control mechanism is proposed to support queued synchronization without contention. By using state-of-the-art Application-Specific Instruction-set Processor (ASIP) technology, we embed the synchronization functionality into a baseline processor, making the proposed mechanism feature ultra-low overhead. Experimental results show the proposed synchronization achieves ultra-low latency and almost ideal scalability when the number of processors increases.

  • Computational Complexity of Generalized Forty Thieves

    Chuzo IWAMOTO  Yuta MATSUI  

     
    LETTER-Fundamentals of Information Systems

      Pubricized:
    2014/11/11
      Vol:
    E98-D No:2
      Page(s):
    429-432

    Forty Thieves is a solitaire game with two 52-card decks. The object is to move all cards from ten tableau piles of four cards to eight foundations. Each foundation is built up by suit from ace to king of the same suit, and each tableau pile is built down by suit. You may move the top card from any tableau pile to a tableau or foundation pile, and from the stock to a foundation pile. We prove that the generalized version of Forty Thieves is NP-complete.

  • Online Synthesis of Conjunctive Decentralized Diagnosers for Discrete Event Systems

    Takashi YAMAMOTO  Shigemasa TAKAI  

     
    LETTER

      Vol:
    E98-A No:2
      Page(s):
    650-653

    In this paper, we consider a decentralized failure diagnosis problem for discrete event systems. For a conjunctively codiagnosable system, there exists a conjunctive decentralized diagnoser that can detect the occurrence of any failure within a uniformly bounded number of steps. We present a method for synthesizing such a conjunctive decentralized diagnoser as an online diagnoser.

  • Circular Polarized Optical OFDM for Optical Wireless Communication

    Kazuo HAGIHARA  Kouji OHUCHI  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    520-527

    As one of optical wireless Orthogonal Frequency Division Multiplexing (OFDM) systems, there is Flip-OFDM, which separates an OFDM signal into positive and negative parts and transmits them. It has good power efficiency and low hardware complexity. However, the system halves transmission efficiency compared with Direct Current-biased Optical OFDM. In this paper, Circular Polarized Optical OFDM (CPO-OFDM) is presented. This system separates OFDM signals into positive and negative parts, and it converts these signals into left-handed and right-handed polarization, and it multiplexes these signals. CPO-OFDM is analyzed with an intensity modulation/direct detection channel model which considers the change of the state of polarization owing to free space propagation. As a result of the analysis, it is shown that CPO-OFDM is a flexible system like the conventional systems by using circular polarization and it has the equivalent bit error rate (BER) and the double transmission efficiency compared with Flip-OFDM. The IM/DD channel model which considers the degree of polarization (DOP) is also shown. As for the DOP, it improves by the increase of the propagation distance. Thus, we can achieve the equivalent BER obtained with a high DOP laser even if we use a low DOP laser.

  • Hybrid Station Aided Coexistence Scheme between Wireless PANs and Wireless LAN

    Fumihiro INOUE  Takayuki NISHIO  Masahiro MORIKURA  Koji YAMAMOTO  Fusao NUNO  Takatoshi SUGIYAMA  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    578-588

    The problem of coexistence between IEEE 802.11g based wireless LANs (WLANs) and IEEE 802.15.4 based wireless personal area networks (WPANs) in the 2.4GHz band is an important issue for the operation of a home energy management system (HEMS) for smart grids. This paper proposes a coexistence scheme that is called a Hybrid station aided coexistence (HYSAC) scheme to solve this problem. This scheme employs a hybrid-station (H-STA) that possesses two types of network device functions. The scheme improves the data transmission quality of the WPAN devices which transmit energy management information such as power consumption. The proposed HYSAC scheme employs WLAN control frames, which are used to assign WPAN system traffic resources. Moreover, we propose a coexistence method to achieve excellent WLAN throughput where multiple WPANs coexist with a WLAN. We theoretically derive the performance of the proposed scheme by considering the QoS support in WLAN and show that the results of the simulation and theoretical analysis are in good agreement. The numerical results show that the HYSAC scheme decreases the beacon loss rate of WPAN to less than 1% when the WLAN system consists of 10 STAs under saturated traffic conditions. Furthermore, the WLAN throughput of the proposed synchronization method is shown to be 30.6% higher than that of the HYSAC scheme without synchronization when the WLAN that consists of 10 STAs coexists with four WPANs.

  • Zero Forcing Beamforming Based Coordinated Scheduling Algorithm for Downlink Coordinated Multi-Point Transmission System

    Ping WANG  Lei DING  Huifang PANG  Fuqiang LIU  Nguyen Ngoc VAN  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E98-B No:2
      Page(s):
    352-359

    In a multi-cell MIMO system, the rate of edge users is limited by the inter-cell co-channel interference. The CoMP scheme which includes Joint Process (JP) and Coordinated Scheduling/Beamforming (CS/CB) was developed to reduce the inter-cell interference and enhance the edge rate. Because CS/CB can alleviate the overhead of network, it gains attention recently. In this paper, a modified zero forcing beamforming (ZFBF) is applied to downlink transmission in a two-cell MIMO system. In order to enhance system sum rate, a novel coordinated user scheduling algorithm is proposed. Firstly, we select users with high correlation among cross-channels as candidates, and then group users from candidates with high orthogonality among direct-channels, and match user groups in different cells as the final scheduling group pair. Simulations show that the proposed algorithm can achieve a higher system sum rate with low complexity than traditional scheduling algorithms.

  • Automatic Induction of Romanization Systems from Bilingual Corpora

    Keiko TAGUCHI  Andrew FINCH  Seiichi YAMAMOTO  Eiichiro SUMITA  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2014/11/14
      Vol:
    E98-D No:2
      Page(s):
    381-393

    In this article we present a novel corpus-based method for inducing romanization systems for languages through a bilingual alignment of transliteration word pairs. First, the word pairs are aligned using a non-parametric Bayesian approach, and then for each grapheme sequence to be romanized, a particular romanization is selected according to a user-specified criterion. As far as we are aware, this paper is the only one to describe a method for automatically deriving complete romanization systems. Unlike existing human-derived romanization systems, the proposed method is able to discover induced romanization systems tailored for specific purposes, for example, for use in data mining, or efficient user input methods. Our experiments study the romanization of four totally different languages: Russian, Japanese, Hindi and Myanmar. The first two languages already have standard romanization systems in regular use, Hindi has a large number of diverse systems, and Myanmar has no standard system for romanization. We compare our induced romanization system to existing systems for Russian and Japanese. We find that the systems so induced are almost identical to Russian, and 69% identical to Japanese. We applied our approach to the task of transliteration mining, and used Levenshtein distance as the romanization selection criterion. Our experiments show that our induced romanization system was able to match the performance of the human created system for Russian, and offer substantially improved mining performance for Japanese. We provide an analysis of the mechanism our approach uses to improve mining performance, and also analyse the differences in characteristics between the induced system for Japanese and the official Japanese Nihon-shiki system. In order to investigate the limits of our approach, we studied the romanization of Myanmar, a low-resource language with a large vocabulary of graphemes. We estimate the approximate corpus size required to effectively romanize the most frequency k graphemes in the language for all values of k up to 1800.

  • Efficient Hair Rendering under Dynamic, Low-Frequency Environmental Light Using Spherical Harmonics

    Xiaoxiong XING  Yoshinori DOBASHI  Tsuyoshi YAMAMOTO  Yosuke KATSURA  Ken ANJYO  

     
    PAPER-Computer Graphics

      Pubricized:
    2014/10/29
      Vol:
    E98-D No:2
      Page(s):
    404-411

    We present an algorithm for efficient rendering of animated hair under a dynamic, low-frequency lighting environment. We use spherical harmonics (SH) to represent the environmental light. The transmittances between a point on a hair strand and the light sources are also represented by SH functions. Then, a convolution of SH functions and the scattering function of a hair strand is precomputed. This allows us to efficiently compute the intensity at a point on the hair. However, the computation of the transmittance is very time-consuming. We address this problem by using a voxel-based approach: the transmittance is computed by using a voxelized hair model. We further accelerate the computation by sampling the voxels. By using our method, we can render a hair model consisting of tens of thousands of hair strands at interactive frame rates.

  • The Implementation of Texture-Based Video Up-Scaling on Coarse-Grained Reconfigurable Architecture

    Rui SHI  Shouyi YIN  Leibo LIU  Qiongbing LIU  Shuang LIANG  Shaojun WEI  

     
    PAPER-Application

      Pubricized:
    2014/11/19
      Vol:
    E98-D No:2
      Page(s):
    276-287

    Video Up-scaling is a hotspot in TV display area; as an important brunch of Video Up-scaling, Texture-Based Video Up-scaling (TBVU) method shows great potential of hardware implementation. Coarse-grained Reconfigurable Architecture (CGRA) is a very promising processor; it is a parallel computing platform which provides high performance of hardware, high flexibility of software, and dynamical reconfiguration ability. In this paper we propose an implementation of TBVU on CGRA. We fully exploit the characters of TBVU and utilize several techniques to reduce memory I/O operation and total execution time. Experimental results show that our work can greatly reduce the I/O operation and the execution time compared with the non-optimized ones. We also compare our work with other platforms and find great advantage in execution time and resource utilization rate.

  • Received Signal Strength-Based Localization Using Delta Method for Non-cooperative Scenario in Wireless Sensor Networks

    Thu L.N. NGUYEN  Yoan SHIN  

     
    LETTER-Communication Theory and Signals

      Vol:
    E98-A No:1
      Page(s):
    450-454

    In this letter, we consider the localization problem using received signal strength in wireless sensor networks. Working with a simple non-cooperative scenario in an outdoor localization, we transform the received signal strength measurement model to an alternative optimization problem which is much easier to solve and less complex compared to finding the optimum solutions from the maximum likelihood estimator. Then, we can solve a sequence of nonconvex problems as a range constrainted optimization problem, while the estimated solution also guarantees a monotonic convergence to the original solution. Simulation results confirm the effectiveness of our proposed approach.

  • Route Computation for Reliable Delivery of Threshold Secret Shared Content

    Nagao OGINO  Hidetoshi YOKOTA  

     
    PAPER-Network

      Vol:
    E98-B No:1
      Page(s):
    209-218

    A threshold secret sharing scheme protects content by dividing it into many pieces and distributing them among different servers. This scheme can also be utilized for the reliable delivery of important content. Thanks to this scheme, the receiver can still reconstruct the original content even if several pieces are lost during delivery due to a multiple-link failure. Nevertheless, the receiver cannot reconstruct the original content unless it receives pieces more than or equal to the threshold. This paper aims to obtain reliable delivery routes for the pieces, as this will minimize the probability that the receiver cannot reconstruct the original content. Although such a route optimization problem can be formulated using an integer linear programming (ILP) model, computation of globally optimum delivery routes based on the ILP model requires large amounts of computational resources. Thus, this paper proposes a lightweight method for computing suboptimum delivery routes. The proposed greedy method computes each of the delivery routes successively by using the conventional shortest route algorithm repeatedly. The link distances are adjusted iteratively on the basis of the given probability of failure on each link and they are utilized for the calculation of each shortest route. The results of a performance evaluation show that the proposed method can compute sub-optimum delivery routes efficiently thanks to the precise adjustment of the link distances, even in backbone networks on a real-world scale.

  • Robust, Blindly-Detectable, and Semi-Reversible Technique of Audio Watermarking Based on Cochlear Delay Characteristics

    Masashi UNOKI  Ryota MIYAUCHI  

     
    PAPER

      Vol:
    E98-D No:1
      Page(s):
    38-48

    We previously proposed an inaudible non-blind digital-audio watermarking approach based on cochlear delay (CD) characteristics. There are, however, three remaining issues with regard to blind-detectability, frame synchronization related to confidentiality, and reversibility. We attempted to solve these issues in developing the proposed approach by taking blind-detectability and reversibility of audio watermarking into consideration. Frame synchronization was also incorporated into the proposed approach to improve confidentiality. We evaluated inaudibility, robustness, and reversibility with the new approach by carrying out three objective tests (PEAQ, LSD, and bit-detection or SNR) and six robustness tests. The results revealed that inaudible, robust, blindly-detectable, and semi-reversible watermarking based on CD could be accomplished.

  • Anonymizing Personal Text Messages Posted in Online Social Networks and Detecting Disclosures of Personal Information

    Hoang-Quoc NGUYEN-SON  Minh-Triet TRAN  Hiroshi YOSHIURA  Noboru SONEHARA  Isao ECHIZEN  

     
    PAPER

      Vol:
    E98-D No:1
      Page(s):
    78-88

    While online social networking is a popular way for people to share information, it carries the risk of unintentionally disclosing personal information. One way to reduce this risk is to anonymize personal information in messages before they are posted. Furthermore, if personal information is somehow disclosed, the person who disclosed it should be identifiable. Several methods developed for anonymizing personal information in natural language text simply remove sensitive phrases, making the anonymized text message unnatural. Other methods change the message by using synonymization or structural alteration to create fingerprints for detecting disclosure, but they do not support the creation of a sufficient number of fingerprints for friends of an online social network user. We have developed a system for anonymizing personal information in text messages that generalizes sensitive phrases. It also creates a sufficient number of fingerprints of a message by using synonyms so that, if personal information is revealed online, the person who revealed it can be identified. A distribution metric is used to ensure that the degree of anonymization is appropriate for each group of friends. A threshold is used to improve the naturalness of the fingerprinted messages so that they do not catch the attention of attackers. Evaluation using about 55,000 personal tweets in English demonstrated that our system creates sufficiently natural fingerprinted messages for friends and groups of friends. The practicality of the system was demonstrated by creating a web application for controlling messages posted on Facebook.

  • Application of the Recursive Transfer Method to Flexural Waves II: Reflection Enhancement Caused by Resonant Scattering in Acoustic Waveguide

    Hatsuhiro KATO  Hatsuyoshi KATO  Takaaki ISHII  

     
    PAPER-Numerical Analysis and Optimization

      Vol:
    E98-A No:1
      Page(s):
    354-361

    Resonant scattering of flexural waves in acoustic waveguide is analysed by using the recursive transfer method (RTM). Because flexural waves are governed by a fourth-order differential equation, a localized wave tends to be induced around the scattering region and dampening wave tails from the localized wave may reach the ends of a simulation domain. A notable feature of RTM is its ability to extract the localized wave even if the dampening tail reaches the end of the simulation domain. Using RTM, the enhanced reflection caused by a localized wave is predicted and the shape of the localized wave is explored at its resonance with the incident wave.

1521-1540hit(5900hit)