The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] ATI(18690hit)

2841-2860hit(18690hit)

  • Off-Grid Frequency Estimation with Random Measurements

    Xushan CHEN  Jibin YANG  Meng SUN  Jianfeng LI  

     
    LETTER-Digital Signal Processing

      Vol:
    E100-A No:11
      Page(s):
    2493-2497

    In order to significantly reduce the time and space needed, compressive sensing builds upon the fundamental assumption of sparsity under a suitable discrete dictionary. However, in many signal processing applications there exists mismatch between the assumed and the true sparsity bases, so that the actual representative coefficients do not lie on the finite grid discretized by the assumed dictionary. Unlike previous work this paper introduces the unified compressive measurement operator into atomic norm denoising and investigates the problems of recovering the frequency support of a combination of multiple sinusoids from sub-Nyquist samples. We provide some useful properties to ensure the optimality of the unified framework via semidefinite programming (SDP). We also provide a sufficient condition to guarantee the uniqueness of the optimizer with high probability. Theoretical results demonstrate the proposed method can locate the nonzero coefficients on an infinitely dense grid over a wide range of SNR case.

  • Formation of Polymer Walls by Monomer Aggregation Control Utilizing Substrate-Surface Wettability for Flexible LCDs Open Access

    Seiya KAWAMORITA  Yosei SHIBATA  Takahiro ISHINABE  Hideo FUJIKAKE  

     
    INVITED PAPER

      Vol:
    E100-C No:11
      Page(s):
    1005-1011

    We examined the novel aggregation control of the LC and monomer during formation of the polymer walls from a LC/monomer mixture in order to suppress the presence of the residual monomers and polymer networks in the pixel areas. The method is utilization of the differing wettabilities among LC and monomer molecules on a substrate surface. We patterned a substrate surface with a fluororesin and a polyimide film, and promoted phase separation of the LC and monomer by cooling process. This resulted in the LC and monomer aggregates primarily existing in the pixel areas and non-pixel areas, respectively. Moreover, the polymer-walls structure which was formed in this method partitioned into individual pixels in a lattice region and prevented the LC from flowing. This polymer-walls formation technique will be useful for developing high-quality flexible LCDs.

  • Improvements on Security Evaluation of AES against Differential Bias Attack

    Haruhisa KOSUGE  Hidema TANAKA  

     
    PAPER-Cryptography and Information Security

      Vol:
    E100-A No:11
      Page(s):
    2398-2407

    In ASIACRYPT2015, a new model for the analysis of block cipher against side-channel attack and a dedicated attack, differential bias attack, were proposed by Bogdanov et al. The model assumes an adversary who has leaked values whose positions are unknown and randomly chosen from internal states (random leakage model). This paper improves the security analysis on AES under the random leakage model. In the previous method, the adversary requires at least 234 chosen plaintexts; therefore, it is hard to recover a secret key with a small number of data. To consider the security against the adversary given a small number of data, we reestimate complexity. We propose another hypothesis-testing method which can minimize the number of required data. The proposed method requires time complexity more than t>260 because of time-data tradeoff, and some attacks are tractable under t≤280. Therefore, the attack is a threat for the long-term security though it is not for the short-term security. In addition, we apply key enumeration to the differential bias attack and propose two evaluation methods, information-theoretic evaluation and experimental one with rank estimation. From the evaluations on AES, we show that the attack is a practical threat for the long-term security.

  • Network Function Virtualization: A Survey Open Access

    Malathi VEERARAGHAVAN  Takehiro SATO  Molly BUCHANAN  Reza RAHIMI  Satoru OKAMOTO  Naoaki YAMANAKA  

     
    INVITED PAPER

      Pubricized:
    2017/05/16
      Vol:
    E100-B No:11
      Page(s):
    1978-1991

    The objectives of this survey are to provide an in-depth coverage of a few selected research papers that have made significant contributions to the development of Network Function Virtualization (NFV), and to provide readers insights into the key advantages and disadvantages of NFV and Software Defined Networks (SDN) when compared to traditional networks. The research papers covered are classified into four categories: NFV Infrastructure (NFVI), Network Functions (NFs), Management And Network Orchestration (MANO), and service chaining. The NFVI papers describe “framework” software that implement common functions, such as dynamic scaling and load balancing, required by NF developers. Papers on NFs are classified as offering solutions for software switches or middleboxes. MANO papers covered in this survey are primarily on resource allocation (virtual network embedding), which is an orchestrator function. Finally, service chaining papers that offer examples and extensions are reviewed. Our conclusions are that with the current level of investment in NFV from cloud and Internet service providers, the promised cost savings are likely to be realized, though many challenges remain.

  • Energy-Efficient Resource Allocation Strategy for Low Probability of Intercept and Anti-Jamming Systems

    Yu Min HWANG  Jun Hee JUNG  Kwang Yul KIM  Yong Sin KIM  Jae Seang LEE  Yoan SHIN  Jin Young KIM  

     
    LETTER-Digital Signal Processing

      Vol:
    E100-A No:11
      Page(s):
    2498-2502

    The aim of this letter is to guarantee the ability of low probability of intercept (LPI) and anti-jamming (AJ) by maximizing the energy efficiency (EE) to improve wireless communication survivability and sustain wireless communication in jamming environments. We studied a scenario based on one transceiver pair with a partial-band noise jammer in a Rician fading channel and proposed an EE optimization algorithm to solve the optimization problem. With the proposed EE optimization algorithm, the LPI and AJ can be simultaneously guaranteed while satisfying the constraint of the maximum signal-to-jamming-and-noise ratio and combinatorial subchannel allocation condition, respectively. The results of the simulation indicate that the proposed algorithm is more energy-efficient than those of the baseline schemes and guarantees the LPI and AJ performance in a jamming environment.

  • Real-Time Object Tracking via Fusion of Global and Local Appearance Models

    Ju Hong YOON  Jungho KIM  Youngbae HWANG  

     
    LETTER-Image Recognition, Computer Vision

      Pubricized:
    2017/08/07
      Vol:
    E100-D No:11
      Page(s):
    2738-2743

    In this letter, we propose a robust and fast tracking framework by combining local and global appearance models to cope with partial occlusion and pose variations. The global appearance model is represented by a correlation filter to efficiently estimate the movement of the target and the local appearance model is represented by local feature points to handle partial occlusion and scale variations. Then global and local appearance models are unified via the Bayesian inference in our tracking framework. We experimentally demonstrate the effectiveness of the proposed method in both terms of accuracy and time complexity, which takes 12ms per frame on average for benchmark datasets.

  • Forecasting Network Traffic at Large Time Scales by Using Dual-Related Method

    Liangrui TANG  Shiyu JI  Shimo DU  Yun REN  Runze WU  Xin WU  

     
    PAPER-Network

      Pubricized:
    2017/04/24
      Vol:
    E100-B No:11
      Page(s):
    2049-2059

    Network traffic forecasts, as it is well known, can be useful for network resource optimization. In order to minimize the forecast error by maximizing information utilization with low complexity, this paper concerns the difference of traffic trends at large time scales and fits a dual-related model to predict it. First, by analyzing traffic trends based on user behavior, we find both hour-to-hour and day-to-day patterns, which means that models based on either of the single trends are unable to offer precise predictions. Then, a prediction method with the consideration of both daily and hourly traffic patterns, called the dual-related forecasting method, is proposed. Finally, the correlation for traffic data is analyzed based on model parameters. Simulation results demonstrate the proposed model is more effective in reducing forecasting error than other models.

  • Detecting Semantic Communities in Social Networks

    Zhen LI  Zhisong PAN  Guyu HU  Guopeng LI  Xingyu ZHOU  

     
    LETTER-Graphs and Networks

      Vol:
    E100-A No:11
      Page(s):
    2507-2512

    Community detection is an important task in the social network analysis field. Many detection methods have been developed; however, they provide little semantic interpretation for the discovered communities. We develop a framework based on joint matrix factorization to integrate network topology and node content information, such that the communities and their semantic labels are derived simultaneously. Moreover, to improve the detection accuracy, we attempt to make the community relationships derived from two types of information consistent. Experimental results on real-world networks show the superior performance of the proposed method and demonstrate its ability to semantically annotate communities.

  • Weighted Voting of Discriminative Regions for Face Recognition

    Wenming YANG  Riqiang GAO  Qingmin LIAO  

     
    LETTER-Image Recognition, Computer Vision

      Pubricized:
    2017/08/04
      Vol:
    E100-D No:11
      Page(s):
    2734-2737

    This paper presents a strategy, Weighted Voting of Discriminative Regions (WVDR), to improve the face recognition performance, especially in Small Sample Size (SSS) and occlusion situations. In WVDR, we extract the discriminative regions according to facial key points and abandon the rest parts. Considering different regions of face make different contributions to recognition, we assign weights to regions for weighted voting. We construct a decision dictionary according to the recognition results of selected regions in the training phase, and this dictionary is used in a self-defined loss function to obtain weights. The final identity of test sample is the weighted voting of selected regions. In this paper, we combine the WVDR strategy with CRC and SRC separately, and extensive experiments show that our method outperforms the baseline and some representative algorithms.

  • A Study of Qualitative Knowledge-Based Exploration for Continuous Deep Reinforcement Learning

    Chenxi LI  Lei CAO  Xiaoming LIU  Xiliang CHEN  Zhixiong XU  Yongliang ZHANG  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2017/07/26
      Vol:
    E100-D No:11
      Page(s):
    2721-2724

    As an important method to solve sequential decision-making problems, reinforcement learning learns the policy of tasks through the interaction with environment. But it has difficulties scaling to large-scale problems. One of the reasons is the exploration and exploitation dilemma which may lead to inefficient learning. We present an approach that addresses this shortcoming by introducing qualitative knowledge into reinforcement learning using cloud control systems to represent ‘if-then’ rules. We use it as the heuristics exploration strategy to guide the action selection in deep reinforcement learning. Empirical evaluation results show that our approach can make significant improvement in the learning process.

  • An Incremental Simulation Technique Based on Delta Model for Lifetime Yield Analysis

    Nguyen Cao QUI  Si-Rong HE  Chien-Nan Jimmy LIU  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E100-A No:11
      Page(s):
    2370-2378

    As devices continue to shrink, the parameter shift due to process variation and aging effects has an increasing impact on the circuit yield and reliability. However, predicting how long a circuit can maintain its design yield above the design specification is difficult because the design yield changes during the aging process. Moreover, performing Monte Carlo (MC) simulation iteratively during aging analysis is infeasible. Therefore, most existing approaches ignore the continuity during simulations to obtain high speed, which may result in accumulation of extrapolation errors with time. In this paper, an incremental simulation technique is proposed for lifetime yield analysis to improve the simulation speed while maintaining the analysis accuracy. Because aging is often a gradual process, the proposed incremental technique is effective for reducing the simulation time. For yield analysis with degraded performance, this incremental technique also reduces the simulation time because each sample is the same circuit with small parameter changes in the MC analysis. When the proposed dynamic aging sampling technique is employed, 50× speedup can be obtained with almost no decline accuracy, which considerably improves the efficiency of lifetime yield analysis.

  • Convex Filter Networks Based on Morphological Filters and their Application to Image Noise and Mask Removal

    Makoto NAKASHIZUKA  Kei-ichiro KOBAYASHI  Toru ISHIKAWA  Kiyoaki ITOI  

     
    PAPER-Image Processing

      Vol:
    E100-A No:11
      Page(s):
    2238-2247

    This paper presents convex filter networks that are obtained from extensions of morphological filters. The proposed filter network consists of a convex and concave filter that are extensions of the dilation and erosion of mathematical morphology with the maxout activation function. Maxout can approximate arbitrary convex functions as piecewise linear functions, including the max function. The class of the convex function hence includes the morphological dilation and can be trained for specific image processing tasks. In this paper, the closing filter is extended to a convex-concave filter network with maxout. The convex-concave filter is trained by the stochastic gradient method for noise and mask removal. The examples of noise and mask removal show that the convex-concave filter can obtain a recovered image, whose quality is comparable to inpainting by using the total variation minimization with reduced computational cost without mask information of the corrupted pixels.

  • The Crosscorrelation of Binary Interleaved Sequences of Period 4N

    Tongjiang YAN  Ruixia YUAN  Xiao MA  

     
    LETTER-Cryptography and Information Security

      Vol:
    E100-A No:11
      Page(s):
    2513-2517

    In this paper, we consider the crosscorrelation of two interleaved sequences of period 4N constructed by Gong and Tang which has been proved to possess optimal autocorrelation. Results show that the interleaved sequences achieve the largest crosscorrelation value 4.

  • Price-Based Power Allocation with Rate Proportional Fairness Constraint in Downlink Non-Orthogonal Multiple Access Systems

    Zi-fu FAN  Chen-chen WEN  Zheng-qiang WANG  Xiao-yu WAN  

     
    LETTER-Communication Theory and Signals

      Vol:
    E100-A No:11
      Page(s):
    2543-2546

    In this letter, we investigate the price-based power allocation with rate proportional fairness constraint in downlink non-orthogonal multiple access (NOMA) systems. The Stackelberg game is utilized to model the interaction between the base station (BS) and users. The revenue maximization problem of the BS is first converted to rate allocation problem, then the optimal rate allocation for each user is obtained by variable substitution. Finally, a price-based power allocation with rate proportional fairness (PAPF) algorithm is proposed based on the relationship between rate and transmit power. Simulation results show that the proposed PAPF algorithm is superior to the previous price-based power allocation algorithm in terms of fairness index and minimum normalized user (MNU) rate.

  • Surface Height Change Estimation Method Using Band-Divided Coherence Functions with Fully Polarimetric SAR Images

    Ryo OYAMA  Shouhei KIDERA  Tetsuo KIRIMOTO  

     
    PAPER-Sensing

      Pubricized:
    2017/05/19
      Vol:
    E100-B No:11
      Page(s):
    2087-2093

    Microwave imaging techniques, in particular, synthetic aperture radar (SAR), are promising tools for terrain surface measurement, irrespective of weather conditions. The coherent change detection (CCD) method is being widely applied to detect surface changes by comparing multiple complex SAR images captured from the same scanning orbit. However, in the case of a general damage assessment after a natural disaster such as an earthquake or mudslide, additional about surface change, such as surface height change, is strongly required. Given this background, the current study proposes a novel height change estimation method using a CCD model based on the Pauli decomposition of fully polarimetric SAR images. The notable feature of this method is that it can offer accurate height change beyond the assumed wavelength, by introducing the frequency band-divided approach, and so is significantly better than InSAR based approaches. Experiments in an anechoic chamber on a 1/100 scaled model of the X-band SAR system, show that our proposed method outputs more accurate height change estimates than a similar method that uses single polarimetric data, even if the height change amount is over the assumed wavelength.

  • Hue-Preserving Color Image Processing with a High Arbitrariness in RGB Color Space

    Minako KAMIYAMA  Akira TAGUCHI  

     
    PAPER-Image Processing

      Vol:
    E100-A No:11
      Page(s):
    2256-2265

    Preserving hue is an important issue for color image processing. In order to preserve hue, color image processing is often carried out in HSI or HSV color space which is translated from RGB color space. Transforming from RGB color space to another color space and processing in this space usually generate gamut problem. We propose image enhancement methods which conserve hue and preserve the range (gamut) of the R, G, B channels in this paper. First we show an intensity processing method while preserving hue and saturation. In this method, arbitrary gray-scale transformation functions can be applied to the intensity component. Next, a saturation processing method while preserving hue and intensity is proposed. Arbitrary gray-scale transform methods can be also applied to the saturation component. Two processing methods are completely independent. Therefore, two methods are easily combined by applying two processing methods in succession. The combination method realizes the hue-preserving color image processing with a high arbitrariness without gamut problem. Furthermore, the concrete enhancement algorithm based on the proposed processing methods is proposed. Numerical results confirm our theoretical results and show that our processing algorithm performs much better than the conventional hue-preserving methods.

  • Subcarrier-Selectable Short Preamble for OFDM Channel Estimation in Real-Time Wireless Control Systems

    Theerat SAKDEJAYONT  Chun-Hao LIAO  Makoto SUZUKI  Hiroyuki MORIKAWA  

     
    PAPER-Communication Systems

      Vol:
    E100-A No:11
      Page(s):
    2323-2331

    Real-time and reliable radio communication is essential for wireless control systems (WCS). In WCS, preambles create significant overhead and affect the real-time capability since payloads are typically small. To shorten the preamble transmission time in OFDM systems, previous works have considered adopting either time-direction extrapolation (TDE) or frequency-direction interpolation (FDI) for channel estimation which however result in poor performance in fast fading channels and frequency-selective fading channels, respectively. In this work, we propose a subcarrier-selectable short preamble (SSSP) by introducing selectability to subcarrier sampling patterns of a preamble such that it can provide full sampling coverage of all subcarriers with several preamble transmissions. In addition, we introduce adaptability to a channel estimation algorithm for the SSSP so that it conforms to both fast and frequency-selective channels. Simulation results validate the feasibility of the proposed method in terms of the reliability and real-time capability. In particular, the SSSP scheme shows its advantage in flexibility as it can provide a low error rate and short communication time in various channel conditions.

  • Rational Proofs against Rational Verifiers

    Keita INASAWA  Kenji YASUNAGA  

     
    PAPER-Cryptography and Information Security

      Vol:
    E100-A No:11
      Page(s):
    2392-2397

    Rational proofs, introduced by Azar and Micali (STOC 2012), are a variant of interactive proofs in which the prover is rational, and may deviate from the protocol for increasing his reward. Guo et al. (ITCS 2014) demonstrated that rational proofs are relevant to delegation of computation. By restricting the prover to be computationally bounded, they presented a one-round delegation scheme with sublinear verification for functions computable by log-space uniform circuits with logarithmic depth. In this work, we study rational proofs in which the verifier is also rational, and may deviate from the protocol for decreasing the prover's reward. We construct a three-message delegation scheme with sublinear verification for functions computable by log-space uniform circuits with polylogarithmic depth in the random oracle model.

  • Distortion Control and Optimization for Lossy Embedded Compression in Video Codec System

    Li GUO  Dajiang ZHOU  Shinji KIMURA  Satoshi GOTO  

     
    PAPER-Coding Theory

      Vol:
    E100-A No:11
      Page(s):
    2416-2424

    For mobile video codecs, the huge energy dissipation for external memory traffic is a critical challenge under the battery power constraint. Lossy embedded compression (EC), as a solution to this challenge, is considered in this paper. While previous studies in lossy EC mostly focused on algorithm optimization to reduce distortion, this work, to the best of our knowledge, is the first one that addresses the distortion control. Firstly, from both theoretical analysis and experiments for distortion optimization, a conclusion is drawn that, at the frame level, allocating memory traffic evenly is a reliable approximation to the optimal solution to minimize quality loss. Then, to reduce the complexity of decoding twice, the distortion between two sequences is estimated by a linear function of that calculated within one sequence. Finally, on the basis of even allocation, the distortion control is proposed to determine the amount of memory traffic according to a given distortion limitation. With the adaptive target setting and estimating function updating in each group of pictures (GOP), the scene change in video stream is supported without adding a detector or retraining process. From experimental results, the proposed distortion control is able to accurately fix the quality loss to the target. Compared to the baseline of negative feedback on non-referred B frames, it achieves about twice memory traffic reduction.

  • Maximizing the Throughput of Wi-Fi Mesh Networks with Distributed Link Activation

    Jae-Young YANG  Ledan WU  Yafeng ZHOU  Joonho KWON  Han-You JEONG  

     
    PAPER-Mobile Information Network and Personal Communications

      Vol:
    E100-A No:11
      Page(s):
    2425-2438

    In this paper, we study Wi-Fi mesh networks (WMNs) as a promising candidate for wireless networking infrastructure that interconnects a variety of access networks. The main performance bottleneck of a WMN is their limited capacity due to the packet collision from the contention-based IEEE 802.11s MAC. To mitigate this problem, we present the distributed link-activation (DLA) protocol which activates a set of collision-free links for a fixed amount of time by exchanging a few control packets between neighboring MRs. Through the rigorous proof, it is shown that the upper bound of the DLA rounds is O(Smax), where Smax is the maximum number of (simultaneous) interference-free links in a WMN topology. Based on the DLA, we also design the distributed throughput-maximal scheduling (D-TMS) scheme which overlays the DLA protocol on a new frame architecture based on the IEEE 802.11 power saving mode. To mitigate its high latency, we propose the D-TMS adaptive data-period control (D-TMS-ADPC) that adjusts the data period depending on the traffic load of a WMN. Numerical results show that the D-TMS-ADPC scheme achieves much higher throughput performance than the IEEE 802.11s MAC.

2841-2860hit(18690hit)