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[Keyword] ATI(18690hit)

3841-3860hit(18690hit)

  • Interference Cancellation for Intra and Inter UWB Systems Using Modified Hermite Polynomials Based Orthogonal Matched Filter

    Takumi KOBAYASHI  Chika SUGIMOTO  Ryuji KOHNO  

     
    PAPER

      Vol:
    E99-B No:3
      Page(s):
    569-577

    Ultra-wideband (UWB) communications is used for medical information communication technology (MICT) as a dependable and safe communication technology in recent years. On the other hand, there are existing various UWB systems that are not used for MICT. Generally, these UWB systems use almost the same frequency band. Therefore, they interfere to each other in general transmission channel environment. In our previous work, a novel UWB pulse shape modulation using modified Hermite pulse is proposed as a multiple user access scheme. In this paper, we propose a mitigation method for inter-user interference and inter-system interference using combination of orthogonal pulse shape modulation and orthogonal matched filter (OMF) detector. The purposes of our system are to detect all signals of users in the same UWB system and to reduce the unknown interference from other UWB systems at the same time. This paper provides performance evaluation results based on both of analytical and numerical evaluation. Simulation results show that the proposed system can detect the signals that were transmitted from the same UWB system using orthogonal pulse set, while the proposed system can reduce the interference from unknown UWB systems at the same time. The theoretical analysis is expected that noise tolerance of our proposal will be deteriorated in the additive Gaussian noise channel in comparison with the conventional matched filter. It is confirmed that the numerical evaluation illustrates such noise tolerance equivalent to the theoretical analysis result.

  • Multi-Layer Perceptron with Pulse Glial Chain

    Chihiro IKUTA  Yoko UWATE  Yoshifumi NISHIO  Guoan YANG  

     
    PAPER-Neural Networks and Bioengineering

      Vol:
    E99-A No:3
      Page(s):
    742-755

    Glial cells include several types of cells such as astrocytes, and oligodendrocytes apart from the neurons in the brain. In particular, astrocytes are known to be important in higher brain function and are therefore sometimes simply called glial cells. An astrocyte can transmit signals to other astrocytes and neurons using ion concentrations. Thus, we expect that the functions of an astrocyte can be applied to an artificial neural network. In this study, we propose a multi-layer perceptron (MLP) with a pulse glial chain. The proposed MLP contains glia (astrocytes) in a hidden layer. The glia are connected to neurons and are excited by the outputs of the neurons. The excited glia generate pulses that affect the excitation thresholds of the neurons and their neighboring glia. The glial network provides a type of positional relationship between the neurons in the hidden layer, which can enhance the performance of MLP learning. We confirm through computer simulations that the proposed MLP has better learning performance than a conventional MLP.

  • Wheeze Detection Algorithm Based on Correlation-Coefficients Analysis

    Jiarui LI  Ying HONG  Chengpeng HAO  

     
    LETTER-Digital Signal Processing

      Vol:
    E99-A No:3
      Page(s):
    760-764

    Wheeze is a general sign for obstructive airway diseases whose clinical diagnosis mainly depends on auscultating or X-ray imaging with subjectivity or harm. Therefore, this paper introduces an automatic, noninvasive method to detect wheeze which consists of STFT decomposition, preprocessing of the spectrogram, correlation-coefficients calculating and duration determining. In particular, duration determining takes the Haas effect into account, which facilitates us to achieve a better determination. Simulation result shows that the sensibility (SE), the specificity (SP) and the accuracy (AC) are 88.57%, 97.78% and 93.75%, respectively, which indicates that this method could be an efficient way to detect wheeze.

  • An Area-Efficient Scalable Test Module to Support Low Pin-Count Testing

    Tong-Yu HSIEH  Tai-Ping WANG  Shuo YANG  Chin-An HSU  Yi-Lung LIN  

     
    PAPER-Electronic Circuits

      Vol:
    E99-C No:3
      Page(s):
    404-414

    Low pin-count testing is an effective method to reduce test cost. Based on this method multi-site testing, i.e., where multiple devices are tested concurrently, can be supported under the limitation on the number of channels provided by ATE. In this work we propose a scalable test module (called STM) design that can support multi-site testing more efficiently when compared with previous work. In the previous work, the total number of devices that can be tested concurrently is usually fixed when the design for testability hardware is designed. For our STM, each STM can deal with a number of circuits to be tested at the same time. Moreover, STM is scalable, i.e., multiple STMs can work collaboratively while the ATE bandwidth still remains the same to further increase the degree of test parallelism. Our STM will be integrated with ATE and serve as an interface between ATE and circuits under test (CUT). Only four pins are required by STM to communicate with ATE, and IEEE 1149.1 Std. ports are employed to transfer test data to/from CUTs. STM has been verified via silicon proof, which contains only about 2,768 logic gates. Experiments results for a number of ISCAS and IWLS'05 benchmark circuits also demonstrate that by making good use of the scalable feature of STM, test efficiency can be enhanced significantly.

  • A Moving Source Localization Method Using TDOA, FDOA and Doppler Rate Measurements

    Dexiu HU  Zhen HUANG  Xi CHEN  Jianhua LU  

     
    PAPER-Sensing

      Vol:
    E99-B No:3
      Page(s):
    758-766

    This paper proposes a moving source localization method that combines TDOA, FDOA and doppler rate measurements. First, the observation equations are linearized by introducing nuisance variables and an initial solution of all the variables is acquired using the weighted least squares method. Then, the Taylor expression and gradient method is applied to eliminate the correlation between the elements in the initial solution and obtain the final estimation of the source position and velocity. The proposed method achieves CRLB derived using TDOA, FDOA and doppler rate and is much more accurate than the conventional TDOA/FDOA based method. In addition, it can avoid the rank-deficiency problem and is more robust than the conventional method. Simulations are conducted to examine the algorithm's performance and compare it with conventional TDOA/FDOA based method.

  • Integrating Multiple Global and Local Features by Product Sparse Coding for Image Retrieval

    Li TIAN  Qi JIA  Sei-ichiro KAMATA  

     
    PAPER-Image Recognition, Computer Vision

      Pubricized:
    2015/12/21
      Vol:
    E99-D No:3
      Page(s):
    731-738

    In this study, we propose a simple, yet general and powerful framework of integrating multiple global and local features by Product Sparse Coding (PSC) for image retrieval. In our framework, multiple global and local features are extracted from images and then are transformed to Trimmed-Root (TR)-features. After that, the features are encoded into compact codes by PSC. Finally, a two-stage ranking strategy is proposed for indexing in retrieval. We make three major contributions in this study. First, we propose TR representation of multiple image features and show that the TR representation offers better performance than the original features. Second, the integrated features by PSC is very compact and effective with lower complexity than by the standard sparse coding. Finally, the two-stage ranking strategy can balance the efficiency and memory usage in storage. Experiments demonstrate that our compact image representation is superior to the state-of-the-art alternatives for large-scale image retrieval.

  • Dynamic Inbound Rate Adjustment Scheme for Virtualized Cloud Data Centers

    Jaehyun HWANG  Cheol-Ho HONG  Hyo-Joong SUH  

     
    LETTER-Information Network

      Pubricized:
    2015/11/30
      Vol:
    E99-D No:3
      Page(s):
    760-762

    This paper proposes a rate adjustment scheme for inbound data traffic on a virtualized host. Most prior studies on network virtualization have only focused on outbound traffic, yet many cloud applications rely on inbound traffic performance. The proposed scheme adjusts the inbound rates of virtual network interfaces dynamically in proportion to the bandwidth demands of the virtual machines.

  • Modulation Format Conversion of OOK to PAM Signals Using Balanced Detection and Intensity Modulation

    Koichi TAKIGUCHI  

     
    BRIEF PAPER-Optoelectronics

      Vol:
    E99-C No:3
      Page(s):
    427-429

    I report modulation format conversion technology that maps on-off keying to 4-level pulse amplitude modulation signals. The conversion technology is based on balanced detection and intensity modulation. Two input optical on-off keying signals into a balanced photo detector produce an electrical signal that drives an intensity modulator to generate an optical pulse amplitude modulation signal. Two 20Gbit/s on-off keying signals were successfully converted into a 40Gbit/s pulse amplitude modulation signal.

  • Closed-Form Approximations for Gaussian Sum Smoother with Nonlinear Model

    Haiming DU  Jinfeng CHEN  Huadong WANG  

     
    PAPER-Digital Signal Processing

      Vol:
    E99-A No:3
      Page(s):
    691-701

    Research into closed-form Gaussian sum smoother has provided an attractive approach for tracking in clutter, joint detection and tracking (in clutter), and multiple target tracking (in clutter) via the probability hypothesis density (PHD). However, Gaussian sum smoother with nonlinear target model has particular nonlinear expressions in the backward smoothed density that are different from the other filters and smoothers. In order to extend the closed-form solution of linear Gaussian sum smoother to nonlinear model, two closed-form approximations for nonlinear Gaussian sum smoother are proposed, which use Gaussian particle approximation and unscented transformation approximation, separately. Since the estimated target number of PHD smoother is not stable, a heuristic approximation method is added. At last, the Bernoulli smoother and PHD smoother are simulated using Gaussian particle approximation and unscented transformation approximation, and simulation results show that the two proposed algorithms can obtain smoothed tracks with nonlinear models, and have better performance than filter.

  • The Structural Vulnerability Analysis of Power Grids Based on Overall Information Centrality

    Yi-Jia ZHANG  Zhong-Jian KANG  Xin-Ling GUO  Zhe-Ming LU  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2015/12/11
      Vol:
    E99-D No:3
      Page(s):
    769-772

    The power grid defines one of the most important technological networks of our times and has been widely studied as a kind of complex network. It has been developed for more than one century and becomes an extremely huge and seemingly robust system. But it becomes extremely fragile as well because some unexpected minimal failures may lead to sudden and massive blackouts. Many works have been carried out to investigate the structural vulnerability of power grids from the topological point of view based on the complex network theory. This Letter focuses on the structural vulnerability of the power grid under the effect of selective node removal. We propose a new kind of node centrality called overall information centrality (OIC) to guide the node removal attack. We test the effectiveness of our centrality in guiding the node removal based on several IEEE power grids. Simulation results show that, compared with other node centralities such as degree centrality (DC), betweenness centrality (BC) and closeness centrality (CC), our OIC is more effective to guide the node removal and can destroy the power grid in less steps.

  • Online Weight Balancing on the Unit Circle

    Hiroshi FUJIWARA  Takahiro SEKI  Toshihiro FUJITO  

     
    PAPER

      Pubricized:
    2015/12/16
      Vol:
    E99-D No:3
      Page(s):
    567-574

    We consider a problem as follows: Given unit weights arriving in an online manner with the total cardinality unknown, upon each arrival we decide where to place it on the unit circle in $mathbb{R}^{2}$. The objective is to set the center of mass of the placed weights as close to the origin as possible. We apply competitive analysis defining the competitive difference as a performance measure. We first present an optimal strategy for placing unit weights which achieves a competitive difference of $ rac{1}{5}$. We next consider a variant in which the destination of each weight must be chosen from a set of positions that equally divide the unit circle. We give a simple strategy whose competitive difference is 0.35. Moreover, in the offline setting, several conditions for the center of mass to lie at the origin are derived.

  • Chunk Size Aware Buffer-Based Algorithm to Improve Viewing Experience in Dynamic HTTP Streaming

    Waqas ur RAHMAN  Kwangsue CHUNG  

     
    PAPER-Multimedia Systems for Communications

      Vol:
    E99-B No:3
      Page(s):
    767-775

    In this paper we propose an adaptive bitrate (ABR) algorithm that selects the video rates by observing and controlling the playback buffer. In a Hypertext Transfer Protocol (HTTP) adaptive streaming session, buffer dynamics largely depend on the chunk sizes. First, we present the algorithm that selects the next video rates based on the current buffer level, while considering the upcoming chunk sizes. We aim to exploit the variation of chunk sizes of a variable bitrate (VBR) encoded video to optimize the tradeoff between the video rate and buffer underflow events while keeping a low frequency of video rate changes. To evaluate the performance of the proposed algorithm, we consider three scenarios: (i) the video flow does not compete with any cross traffic, (ii) the video flow shares the bottleneck link with competing TCP traffic, and (iii) two HTTP clients share the bottleneck. We show that the proposed algorithm selects a high playback video rate and avoids unnecessary rebuffering while keeping a low frequency of video rate changes. Furthermore, we show that the proposed algorithm changes the video quality gradually to guarantee the user's viewing experience.

  • Power Allocation for Secondary Users in Relay Assisted Multi-Band Underlay Cognitive Radio Network

    Wenhao JIANG  Wenjiang FENG  Shaoxiang GU  Yuxiang LIU  Zhiming WANG  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E99-B No:3
      Page(s):
    714-722

    In this paper, we study the power allocation problem in a relay assisted multi-band underlay cognitive radio network. Such a network allows unlicensed users (secondary users) to access the spectrum bands under a transmission power constraint. Due to the concave increasing property of logarithm function, it is not always wise for secondary users to expend all the transmission power in one band if their aim is to maximize achievable data rate. In particular, we study a scenario where two secondary users and a half-duplexing relay exist with two available bands. The two users choose different bands for direct data transmission and use the other band for relay transmission. By properly allocating the power on two bands, each user may be able to increase its total achievable data rate while satisfying the power constraint. We formulate the power allocation problem as a non-cooperative game and investigate its Nash equilibria. We prove the power allocation game is a supermodular game and that Nash equilibria exist. We further find the best response function of users and propose a best response update algorithm to solve the corresponding dynamic game. Numerical results show the overall performance in terms of achievable rates is improved through our proposed transmission scheme and power allocation algorithm. Our proposed algorithm also shows satisfactory performance in terms of convergence speed.

  • Time Performance Optimization and Resource Conflicts Resolution for Multiple Project Management

    Cong LIU  Jiujun CHENG  Yirui WANG  Shangce GAO  

     
    PAPER-Software Engineering

      Pubricized:
    2015/12/04
      Vol:
    E99-D No:3
      Page(s):
    650-660

    Time performance optimization and resource conflict resolution are two important challenges in multiple project management contexts. Compared with traditional project management, multi-project management usually suffers limited and insufficient resources, and a tight and urgent deadline to finish all concurrent projects. In this case, time performance optimization of the global project management is badly needed. To our best knowledge, existing work seldom pays attention to the formal modeling and analyzing of multi-project management in an effort to eliminate resource conflicts and optimizing the project execution time. This work proposes such a method based on PRT-Net, which is a Petri net-based formulism tailored for a kind of project constrained by resource and time. The detailed modeling approaches based on PRT-Net are first presented. Then, resource conflict detection method with corresponding algorithm is proposed. Next, the priority criteria including a key-activity priority strategy and a waiting-short priority strategy are presented to resolve resource conflicts. Finally, we show how to construct a conflict-free PRT-Net by designing resource conflict resolution controllers. By experiments, we prove that our proposed priority strategy can ensure the execution time of global multiple projects much shorter than those without using any strategies.

  • Color-Enriched Gradient Similarity for Retouched Image Quality Evaluation

    Leida LI  Yu ZHOU  Jinjian WU  Jiansheng QIAN  Beijing CHEN  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2015/12/09
      Vol:
    E99-D No:3
      Page(s):
    773-776

    Image retouching is fundamental in photography, which is widely used to improve the perceptual quality of a low-quality image. Traditional image quality metrics are designed for degraded images, so they are limited in evaluating the quality of retouched images. This letter presents a RETouched Image QUality Evaluation (RETIQUE) algorithm by measuring structure and color changes between the original and retouched images. Structure changes are measured by gradient similarity. Color colorfulness and saturation are utilized to measure color changes. The overall quality score of a retouched image is computed as the linear combination of gradient similarity and color similarity. The performance of RETIQUE is evaluated on a public Digitally Retouched Image Quality (DRIQ) database. Experimental results demonstrate that the proposed metric outperforms the state-of-the-arts.

  • Competitive Analysis for the Flat-Rate Problem

    Hiroshi FUJIWARA  Atsushi MATSUDA  Toshihiro FUJITO  

     
    PAPER

      Pubricized:
    2015/12/16
      Vol:
    E99-D No:3
      Page(s):
    559-566

    We consider a problem of the choice of price plans offered by a telecommunications company: a “pay-as-you-go” plan and a “flat-rate” plan. This problem is formulated as an online optimization problem extending the ski-rental problem, and analyzed using the competitive ratio. We give a lemma for easily calculating the competitive ratio. Based on the lemma, we derive a family of optimal strategies for a realistic class of instances.

  • Real Cholesky Factor-ADI Method for Low-Rank Solution of Projected Generalized Lyapunov Equations

    Yuichi TANJI  

     
    PAPER-Nonlinear Problems

      Vol:
    E99-A No:3
      Page(s):
    702-709

    The alternating direction implicit (ADI) method is proposed for low-rank solution of projected generalized continuous-time algebraic Lyapunov equations. The low-rank solution is expressed by Cholesky factor that is similar to that of Cholesky factorization for linear system of equations. The Cholesky factor is represented in a real form so that it is useful for balanced truncation of sparsely connected RLC networks. Moreover, we show how to determine the shift parameters which are required for the ADI iterations, where Krylov subspace method is used for finding the shift parameters that reduce the residual error quickly. In the illustrative examples, we confirm that the real Cholesky factor certainly provides low-rank solution of projected generalized continuous-time algebraic Lyapunov equations. Effectiveness of the shift parameters determined by Krylov subspace method is also demonstrated.

  • Novel Reconfigurable Hardware Accelerator for Protein Sequence Alignment Using Smith-Waterman Algorithm

    Atef IBRAHIM  Hamed ELSIMARY  Abdullah ALJUMAH  

     
    PAPER-Digital Signal Processing

      Vol:
    E99-A No:3
      Page(s):
    683-690

    This paper presents novel reconfigurable semi-systolic array architecture for the Smith-Waterman with an affine gap penalty algorithm to align protein sequences optimized for shorter database sequences. This architecture has been modified to enable hardware reuse rather than replicating processing elements of the semi-systolic array in multiple FPGAs. The proposed hardware architecture and the previously published conventional one are described at the Register Transfer Level (RTL) using VHDL language and implemented using the FPGA technology. The results show that the proposed design has significant higher normalized speedup (up to 125%) over the conventional one for query sequence lengths less than 512 residues. According to the UniProtKB/TrEMBL protein database (release 2015_05) statistics, the largest number of sequences (about 80%) have sequence length less than 512 residues that makes the proposed design outperforms the conventional one in terms of speed and area in this sequence lengths range.

  • Characteristic Analysis and Tolerance Analysis of Nonlinear Resistive Circuits Using Integer Programming

    Kiyotaka YAMAMURA  Suguru ISHIGURO  Hiroshi TAKI  

     
    PAPER-Nonlinear Problems

      Vol:
    E99-A No:3
      Page(s):
    710-719

    This paper presents efficient and easily implementable methods for the characteristic analysis and tolerance analysis of nonlinear resistive circuits using integer programming. In these methods, the problem of finding all characteristic curves or all solution sets (regions of possible operating points) is formulated as a mixed integer programming problem, and it is solved by a high-performance integer programming solver such as CPLEX. It is shown that the proposed methods can easily be implemented without making complicated programs, and that all characteristic curves or all solution sets are obtained by solving mixed integer programming problems several times. Numerical examples are given to confirm the effectiveness of the proposed methods.

  • Speaker-Independent Speech Emotion Recognition Based Multiple Kernel Learning of Collaborative Representation

    Cheng ZHA  Xinrang ZHANG  Li ZHAO  Ruiyu LIANG  

     
    LETTER-Engineering Acoustics

      Vol:
    E99-A No:3
      Page(s):
    756-759

    We propose a novel multiple kernel learning (MKL) method using a collaborative representation constraint, called CR-MKL, for fusing the emotion information from multi-level features. To this end, the similarity and distinctiveness of multi-level features are learned in the kernels-induced space using the weighting distance measure. Our method achieves better performance than existing methods by using the voiced-level and unvoiced-level features.

3841-3860hit(18690hit)