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2181-2200hit(8214hit)

  • A Novel High-Performance Heuristic Algorithm with Application to Physical Design Optimization

    Yiqiang SHENG  Atsushi TAKAHASHI  

     
    PAPER-Physical Level Design

      Vol:
    E97-A No:12
      Page(s):
    2418-2426

    In this paper, a novel high-performance heuristic algorithm, named relay-race algorithm (RRA), which was proposed to approach a global optimal solution by exploring similar local optimal solutions more efficiently within shorter runtime for NP-hard problem is investigated. RRA includes three basic parts: rough search, focusing search and relay. The rough search is designed to get over small hills on the solution space and to approach a local optimal solution as fast as possible. The focusing search is designed to reach the local optimal solution as close as possible. The relay is to escape from the local optimal solution in only one step and to maintain search continuity simultaneously. As one of typical applications, multi-objective placement problem in physical design optimization is solved by the proposed RRA. In experiments, it is confirmed that the computational performance is considerably improved. RRA achieves overall Pareto improvement of two conflicting objectives: power consumption and maximal delay. RRA has its potential applications to improve the existing search methods for more hard problems.

  • On Improving the Performance of a Speech Model-Based Blind Reverberation Time Estimation in Noisy Environments

    Tung-chin LEE  Young-cheol PARK  Dae-hee YOUN  

     
    LETTER-Measurement Technology

      Vol:
    E97-A No:12
      Page(s):
    2688-2692

    This paper proposes a method of improving the performance of blind reverberation time (RT) estimation in noisy environments. RT estimation is conducted using a maximum likelihood (ML) method based on the autocorrelation function of the linear predictive residual signal. To reduce the effect of environmental noise, a noise reduction technique is applied to the noisy speech signal. In addition, a frequency coefficient selection is performed to eliminate signal components with low signal-to-noise ratio (SNR). Experimental results confirm that the proposed method improves the accuracy of RT measures, particularly when the speech signal is corrupted by a colored noise with a narrow bandwidth.

  • Numerical Examination on Effective Permittivity of Two-Dimensional Multilayered Periodic Structures

    Mitsuhiro YOKOTA  Kazumasa MATSUMOTO  

     
    BRIEF PAPER-Electromagnetic Theory

      Vol:
    E97-C No:12
      Page(s):
    1150-1153

    The effective permittivity of the two-dimensional multilayered periodic structures which consist of the rectangular dielectric cylinders is examined numerically. The original periodic structure is replaced with a simple structure such as the dielectric slab. By using the reflectance of the periodic structure obtained by the FDTD method, the effective permittivity of the dielectric slab, which has the same reflectance as that of the periodic structure, is obtained by using the transcendental equation. In order to reduce the procedure to obtain the reflectance from the multilayered periodic structures, the reflectance from one-layered structure is used. The range of the application and validity of this procedure is examined.

  • Illumination Modeling Method for Office Lighting Control by Using RBFNN

    Wa SI  Xun PAN  Harutoshi OGAI  Katsumi HIRAI  Noriyoshi YAMAUCHI  Tansheng LI  

     
    PAPER-Biocybernetics, Neurocomputing

      Vol:
    E97-D No:12
      Page(s):
    3192-3200

    This paper represents an illumination modeling method for lighting control which can model the illumination distribution inside office buildings. The algorithm uses data from the illumination sensors to train Radial Basis Function Neural Networks (RBFNN) which can be used to calculate 1) the illuminance contribution from each luminaire to different positions in the office 2) the natural illuminance distribution inside the office. This method can be used to provide detailed illumination contribution from both artificial and natural light sources for lighting control algorithms by using small amount of sensors. Simulations with DIALux are made to prove the feasibility and accuracy of the modeling method.

  • Asymptotics of Bayesian Inference for a Class of Probabilistic Models under Misspecification

    Nozomi MIYA  Tota SUKO  Goki YASUDA  Toshiyasu MATSUSHIMA  

     
    PAPER-Prediction

      Vol:
    E97-A No:12
      Page(s):
    2352-2360

    In this paper, sequential prediction is studied. The typical assumptions about the probabilistic model in sequential prediction are following two cases. One is the case that a certain probabilistic model is given and the parameters are unknown. The other is the case that not a certain probabilistic model but a class of probabilistic models is given and the parameters are unknown. If there exist some parameters and some models such that the distributions that are identified by them equal the source distribution, an assumed model or a class of models can represent the source distribution. This case is called that specifiable condition is satisfied. In this study, the decision based on the Bayesian principle is made for a class of probabilistic models (not for a certain probabilistic model). The case that specifiable condition is not satisfied is studied. Then, the asymptotic behaviors of the cumulative logarithmic loss for individual sequence in the sense of almost sure convergence and the expected loss, i.e. redundancy are analyzed and the constant terms of the asymptotic equations are identified.

  • On the Wyner-Ziv Source Coding Problem with Unknown Delay

    Tetsunao MATSUTA  Tomohiko UYEMATSU  

     
    PAPER-Shannon Theory

      Vol:
    E97-A No:12
      Page(s):
    2288-2299

    In this paper, we consider the lossy source coding problem with delayed side information at the decoder. We assume that delay is unknown but the maximum of delay is known to the encoder and the decoder, where we allow the maximum of delay to change with the block length. In this coding problem, we show an upper bound and a lower bound of the rate-distortion (RD) function, where the RD function is the infimum of rates of codes in which the distortion between the source sequence and the reproduction sequence satisfies a certain distortion level. We also clarify that the upper bound coincides with the lower bound when maximums of delay per block length converge to a constant. Then, we give a necessary and sufficient condition in which the RD function is equal to that for the case without delay. Furthermore, we give an example of a source which does not satisfy this necessary and sufficient condition.

  • Synthesis Algorithm for Parallel Index Generator

    Yusuke MATSUNAGA  

     
    PAPER-Logic Synthesis, Test and Verification

      Vol:
    E97-A No:12
      Page(s):
    2451-2458

    The index generation function is a multi-valued logic function which checks if the given input vector is a registered or not, and returns its index value if the vector is registered. If the latency of the operation is critical, dedicated hardware is used for implementing the index generation functions. This paper proposes a method implementing the index generation functions using parallel index generator. A novel and efficient algorithm called ‘conflict free partitioning’ is proposed to synthesize parallel index generators. Experimental results show the proposed method outperforms other existing methods. Also, A novel architecture of index generator which is suitable for parallelized implementation is introduced. A new architecture has advantages in the sense of both area and delay.

  • Error Detection Performance of TPSK Using AMI Code in Multi-Hop Communications under Rayleigh Fading Environments

    Kotoko YAMADA  Kouji OHUCHI  

     
    LETTER-Communication Theory and Signals

      Vol:
    E97-A No:12
      Page(s):
    2363-2365

    DetF (Detect-and-Forward) is studied as a relay method in multi-hop networks. When an error detection scheme is introduced, DetF is likely to achieve an efficient transmission. In this study, AMI (Alternate Mark Inversion) code is focused on as an error detection scheme. Error detection performances of ternary PSK (Phase Shift Keying) using AMI code and binary PSK using parity check code are examined. It is shown that ternary PSK using AMI code has a good error detection performance.

  • Channel Prediction Techniques for a Multi-User MIMO System in Time-Varying Environments

    Kanako YAMAGUCHI  Huu Phu BUI  Yasutaka OGAWA  Toshihiko NISHIMURA  Takeo OHGANE  

     
    PAPER-Antennas and Propagation

      Vol:
    E97-B No:12
      Page(s):
    2747-2755

    Although multi-user multiple-input multiple-output (MI-MO) systems provide high data rate transmission, they may suffer from interference. Block diagonalization and eigenbeam-space division multiplexing (E-SDM) can suppress interference. The transmitter needs to determine beamforming weights from channel state information (CSI) to use these techniques. However, MIMO channels change in time-varying environments during the time intervals between when transmission parameters are determined and actual MIMO transmission occurs. The outdated CSI causes interference and seriously degrades the quality of transmission. Channel prediction schemes have been developed to mitigate the effects of outdated CSI. We evaluated the accuracy of prediction of autoregressive (AR)-model-based prediction and Lagrange extrapolation in the presence of channel estimation error. We found that Lagrange extrapolation was easy to implement and that it provided performance comparable to that obtained with the AR-model-based technique.

  • Power Consumption Characteristics of Autonomous Decentralized Clustering Based on Local Interaction

    Ryo HAMAMOTO  Chisa TAKANO  Kenji ISHIDA  Masaki AIDA  

     
    PAPER-Wireless Network

      Vol:
    E97-D No:12
      Page(s):
    2984-2994

    Mobile ad hoc networks (MANETs) consist of mobile terminals that directly connect with one another to communicate without a network infrastructure, such as base stations and/or access points of wireless local area networks (LANs) connected to wired backbone networks. Large-scale disasters such as tsunamis and earthquakes can cause serious damage to life, property as well as any network infrastructure. However, MANETs can function even after severe disasters have destroyed regular network infrastructure. We have proposed an autonomous decentralized structure formation technology based on local interaction, and have applied it to implement autonomous decentralized clustering on MANETs. This method is known to configure clusters that reflect the network condition, such as residual battery power and the degree of each node. However, the effect of clusters that reflect the network condition has not been evaluated. In this study, we configure clusters using our method, the back-diffusion method, and a bio-inspired method, which is a kind of autonomous decentralized clustering that cannot reflect the network condition. We also clarify the importance of clustering that reflects the network condition, with regard to power consumption and data transfer efficiency.

  • A Method to Find Linear Decompositions for Incompletely Specified Index Generation Functions Using Difference Matrix

    Tsutomu SASAO  Yuta URANO  Yukihiro IGUCHI  

     
    PAPER-Logic Synthesis, Test and Verification

      Vol:
    E97-A No:12
      Page(s):
    2427-2433

    This paper shows a method to find a linear transformation that reduces the number of variables to represent a given incompletely specified index generation function. It first generates the difference matrix, and then finds a minimal set of variables using a covering table. Linear transformations are used to modify the covering table to produce a smaller solution. Reduction of the difference matrix is also considered.

  • Finite Length Analysis on Listing Failure Probability of Invertible Bloom Lookup Tables

    Daichi YUGAWA  Tadashi WADAYAMA  

     
    PAPER-Coding Theory

      Vol:
    E97-A No:12
      Page(s):
    2309-2316

    An Invertible Bloom Lookup Tables (IBLT) is a data structure which supports insertion, deletion, retrieval and listing operations for the key-value pair. An IBLT can be used to realize efficient set reconciliation for database synchronization. The most notable feature of the IBLT is the complete listing operation of key-value pairs based on the algorithm similar to the peeling algorithm for low-density parity check (LDPC) codes. In this paper, we will present a stopping set (SS) analysis for the IBLT that reveals finite length behaviors of the listing failure probability. The key of the analysis is enumeration of the number of stopping matrices of given size. We derived a novel recursive formula useful for computationally efficient enumeration. An upper bound on the listing failure probability based on the union bound accurately captures the error floor behaviors.

  • Interactive Evolutionary System for Synthesizing Facial Caricature with Non-planar Expression

    Tatsuya UGAI  Keita SATO  Kaoru ARAKAWA  Hiroshi HARASHIMA  

     
    PAPER

      Vol:
    E97-A No:11
      Page(s):
    2154-2160

    A method to synthesize facial caricatures with non-planar expression is proposed. Several methods have been already proposed to synthesize facial caricatures automatically, but they mainly synthesize plane facial caricatures which look somewhat monotonous. In order to generate expressive facial caricature, the image should be expressed in non-planar style, expressing the depth of the face by shading and highlighting. In this paper, a new method to express such non-planar effect in facial caricatures is proposed by blending the grayscale information of the real face image into the plane caricature. Some methods also have been proposed to generate non-planar facial caricature, but the proposed method can adjust the degree of non-planar expression by interactive evolutionary computing, so that the obtained expression is satisfied by the user based on his/her subjective criteria. Since the color of the face looks changed, when the grayscale information of the natural face image is mixed, the color information of the skin area are also set by interactive evolutionary computing. Experimental results show the high performance of the proposed method.

  • A Novel Structure of HTTP Adaptive Streaming Based on Unequal Error Protection Rateless Code

    Yun SHEN  Yitong LIU  Jing LIU  Hongwen YANG  Dacheng YANG  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E97-D No:11
      Page(s):
    2903-2911

    In this paper, we design an Unequal Error Protection (UEP) rateless code with special coding graph and apply it to propose a novel HTTP adaptive streaming based on UEP rateless code (HASUR). Our designed UEP rateless code provides high diversity on decoding probability and priority for data in different important level with overhead smaller than 0.27. By adopting this UEP rateless channel coding and scalable video source coding, our HASUR ensures symbols with basic quality to be decoded first to guarantee fluent playback experience. Besides, it also provides multiple layers to ensure the most suitable quality for fluctuant bandwidth and packet loss rate (PLR) without estimating them in advance. We evaluate our HASUR against the alternative solutions. Simulation results show that HASUR provides higher video quality and more adapts to bandwidth and PLR than other two commercial schemes under End-to-End transmission.

  • Design and Implementation of Network Virtualization Management System

    Yohei KATAYAMA  Takehito YAMAMOTO  Yukio TSUKISHIMA  Kazuhisa YAMADA  Noriyuki TAKAHASHI  Atsushi TAKAHARA  Akihiro NAKAO  

     
    PAPER

      Vol:
    E97-B No:11
      Page(s):
    2286-2301

    Due to the recent network service market trends, network infrastructure providers must make their network infrastructures tolerant of network service complexity and swift at providing new network services. To achieve this, we first make a design decision for the single domain network infrastructure in which we use network virtualization and separate the network service control and management from the network infrastructure and leave the resource connectivity control and management in the network infrastructure so that the infrastructure can maintain simplicity and the network service can become complex and be quickly provided. Along with the decision, we construct an architecture of the network infrastructure and a network management model. The management model defines a slice as being determined by abstracted resource requirements and restructures the roles and planes from the viewpoint of network infrastructure usability so that network service requesters can manage network resources freely and swiftly in an abstract manner within the authorities the network infrastructure operator provides. We give the details of our design and implementation for a network virtualization management system along with the model. We deployed and evaluated our designed and implemented management system on the Japan national R&E testbed (JGN-X) to confirm the feasibility of our management system design and discuss room for improvement in terms of response time and scalability towards practical use. We also investigated certain cases of sophisticated network functions to confirm that the infrastructure can accept these functions without having to be modified.

  • Cost Function-Based Vector Filter for Suppressing False Color

    Shi BAO  Go TANAKA  

     
    LETTER

      Vol:
    E97-A No:11
      Page(s):
    2184-2188

    In the impulse noise removal from a color image, vector filters are suitable for suppressing false color generation. However, the vector filters do not select optimal vectors to restore noise corrupted pixels. To cope with this problem, a cost function-based vector filter is proposed in this letter.

  • Thickness of Crystalline Layer of Rubbed Polyimide Film Characterized by Grazing Incidence X-ray Diffractions with Multi Incident Angles

    Ichiro HIROSAWA  Tomoyuki KOGANEZAWA  Hidenori ISHII  

     
    BRIEF PAPER

      Vol:
    E97-C No:11
      Page(s):
    1089-1092

    Thickness of crystalline layer induced by annealing after rubbing at surface of polyimide film for liquid crystal displays was estimated to be 3--5 nm by grazing-incidence X-ray diffractions with multi incident angles. Agreement of thickness of crystalline layer with that of initially oriented layer suggests polymer orientation induced by rubbing proceeds crystallization by annealing. Furthermore, no in-plane smectic ordering in bottom 20,nm region of polyimide film was suggested.

  • Fast Mode and Depth Decision for HEVC Intra Prediction Based on Edge Detection and Partition Reconfiguration

    Gaoxing CHEN  Lei SUN  Zhenyu LIU  Takeshi IKENAGA  

     
    PAPER

      Vol:
    E97-A No:11
      Page(s):
    2130-2138

    High efficiency video coding (HEVC) is a video compression standard that outperforms the predecessor H.264/AVC by doubling the compression efficiency. To enhance the intra prediction accuracy, 35 intra prediction modes were used in the prediction units (PUs), with partition sizes ranging from 4 × 4 to 64 × 64 in HEVC. However, the manifold prediction modes dramatically increase the encoding complexity. This paper proposes a fast mode- and depth-decision algorithm based on edge detection and reconfiguration to alleviate the large computational complexity in intra prediction with trivial degradation in accuracy. For mode decision, we propose pixel gradient statistics (PGS) and mode refinement (MR). PGS uses pixel gradient information to assist in selecting the prediction mode after rough mode decision (RMD). MR uses the neighboring mode information to select the best PU mode (BPM). For depth decision, we propose a partition reconfiguration algorithm to replace the original partitioning order with a more reasonable structure, by using the smoothness of the coding unit as a criterion in deciding the prediction depth. Smoothness detection is based on the PGS result. Experiment results show that the proposed method saves about 41.50% of the original processing time with little degradation (BD bitrate increased by 0.66% and BDPSNR decreased by 0.060dB) in the coding gain.

  • In-line Process Monitoring for Amorphous Oxide Semiconductor TFT Fabrication using Microwave-detected Photoconductivity Decay Technique Open Access

    Hiroshi GOTO  Hiroaki TAO  Shinya MORITA  Yasuyuki TAKANASHI  Aya HINO  Tomoya KISHI  Mototaka OCHI  Kazushi HAYASHI  Toshihiro KUGIMIYA  

     
    INVITED PAPER

      Vol:
    E97-C No:11
      Page(s):
    1055-1062

    We have investigated the microwave-detected photoconductivity responses from the amorphous In--Ga--Zn--O (a-IGZO) thin films. The time constant extracted by the slope of the slow part of the reflectivity signals are correlated with TFT performances. We have evaluated the influences of the sputtering conditions on the quality of a-IGZO thin film, as well as the influences of gate insulation films and annealing conditions, by comparing the TFT characteristics with the microwave photoconductivity decay ($mu$-PCD). It is concluded that the $mu$-PCD is a promising method for in-line process monitoring for the IGZO-TFTs fabrication.

  • Signal Detection for EM-Based Iterative Receivers in MIMO-OFDM Mobile Communications

    Kazushi MURAOKA  Kazuhiko FUKAWA  Hiroshi SUZUKI  Satoshi SUYAMA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E97-B No:11
      Page(s):
    2480-2490

    Joint signal detection and channel estimation based on the expectation-maximization (EM) algorithm has been investigated for multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) mobile communications over fast-fading channels. The previous work in [20] developed a channel estimation method suitable for the EM-based iterative receiver. However, it remained possible for unreliable received signals to be repetitively used during the iterative process. In order to improve the EM-based iterative receiver further, this paper proposes spatial removal from the perspective of a message-passing algorithm on factor graphs. The spatial removal performs the channel estimation of a targeted antenna by using detected signals that are obtained from the received signals of all antennas other than the targeted antenna. It can avoid the repetitive use of unreliable received signals for consecutive signal detection and channel estimation. Appropriate applications of the spatial removal are also discussed to exploit both the removal effect and the spatial diversity. Computer simulations under fast-fading conditions demonstrate that the appropriate applications of the spatial removal can improve the packet error rate (PER) of the EM-based receiver thanks to both the removal effect and the spatial diversity.

2181-2200hit(8214hit)