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5921-5940hit(21534hit)

  • Field Slack Assessment for Predictive Fault Avoidance on Coarse-Grained Reconfigurable Devices

    Toshihiro KAMEDA  Hiroaki KONOURA  Dawood ALNAJJAR  Yukio MITSUYAMA  Masanori HASHIMOTO  Takao ONOYE  

     
    PAPER-Test and Verification

      Vol:
    E96-D No:8
      Page(s):
    1624-1631

    This paper proposes a procedure for avoiding delay faults in field with slack assessment during standby time. The proposed procedure performs path delay testing and checks if the slack is larger than a threshold value using selectable delay embedded in basic elements (BE). If the slack is smaller than the threshold, a pair of BEs to be replaced, which maximizes the path slack, is identified. Experimental results with two application circuits mapped on a coarse-grained architecture show that for aging-induced delay degradation a small threshold slack, which is less than 1 ps in a test case, is enough to ensure the delay fault prediction.

  • Fast Iterative Mining Using Sparsity-Inducing Loss Functions

    Hiroto SAIGO  Hisashi KASHIMA  Koji TSUDA  

     
    PAPER-Pattern Recognition

      Vol:
    E96-D No:8
      Page(s):
    1766-1773

    Apriori-based mining algorithms enumerate frequent patterns efficiently, but the resulting large number of patterns makes it difficult to directly apply subsequent learning tasks. Recently, efficient iterative methods are proposed for mining discriminative patterns for classification and regression. These methods iteratively execute discriminative pattern mining algorithm and update example weights to emphasize on examples which received large errors in the previous iteration. In this paper, we study a family of loss functions that induces sparsity on example weights. Most of the resulting example weights become zeros, so we can eliminate those examples from discriminative pattern mining, leading to a significant decrease in search space and time. In computational experiments we compare and evaluate various loss functions in terms of the amount of sparsity induced and resulting speed-up obtained.

  • A Control Method of Dynamic Selfish Routing Based on a State-Dependent Tax

    Takafumi KANAZAWA  Takurou MISAKA  Toshimitsu USHIO  

     
    PAPER-Concurrent Systems

      Vol:
    E96-A No:8
      Page(s):
    1794-1802

    A selfish routing game is a simple model of selfish behaviors in networks. It is called that Braess's paradox occurs in the selfish routing game if an equilibrium flow achieved by players' selfish behaviors is not the optimal minimum latency flow. In order to make the minimum latency flow a Nash equilibrium, a marginal cost tax has been proposed. Braess graphs have also been proposed to discuss Braess's paradox. In a large population of selfish players, conflicts between purposes of each player and the population causes social dilemmas. In game theory, to resolve the social dilemmas, a capitation tax and/or a subsidy has been introduced, and players' dynamical behaviors have been formulated by replicator dynamics. In this paper, we formulate replicator dynamics in the Braess graphs and investigate stability of the minimum latency flow with and without the marginal cost tax. An additional latency caused by the marginal cost tax is also shown. To resolve the problem of the additional latency, we extend the capitation tax and the subsidy to a state-dependent tax and apply it to the stabilization problem of the minimum latency flow.

  • Physical Architecture and Model-Based Evaluation of Electric Power System with Multiple Homes

    Yoshihiko SUSUKI  Ryoya KAZAOKA  Takashi HIKIHARA  

     
    PAPER-Nonlinear Problems

      Vol:
    E96-A No:8
      Page(s):
    1703-1711

    This paper proposes the physical architecture of an electric power system with multiple homes. The notion of home is a unit of small-scale power system that includes local energy source, energy storage, load, power conversion circuits, and control systems. An entire power system consists of multiple homes that are interconnected via a distribution network and that are connected to the commercial power grid. The interconnection is autonomously achieved with a recently developed technology of grid-connected inverters. A mathematical model of slow dynamics of the power system is also developed in this paper. The developed model enables the evaluation of steady and transient characteristics of power systems.

  • Throughput Enhancement with ACK/NACK Mechanism in Short-Range Millimeter-Wave Communication Systems

    Ryoko MATSUO  Tomoya TANDAI  Takeshi TOMIZAWA  Hideo KASAMI  

     
    PAPER-Terrestrial Wireless Communication/Broadcasting Technologies

      Vol:
    E96-B No:8
      Page(s):
    2162-2172

    The 60GHz millimeter-wave (mmWave) wireless technology is a focus of increasing attention, since its ability to transmit more than Gbps PHY data rate makes it suitable for high-speed, short-range applications such as peer-to-peer synchronization and kiosk terminals. In the case of short-range communication with a range of several tens of centimeters, only terminals present in this communication range will be affect and communication is considered to be on a one-to-one basis. In one-to-one communication, a simpler and more efficient access mechanism is preferable. The ability of current CSMA/CA based MAC, for example MAC of IEEE 802.11 WLAN systems, to achieve high throughput is limited by the low MAC efficiency caused by high signal exchange overhead, such as interframe space (IFS) and acknowledgement. This paper proposes an ACK/NACK mechanism that enhances the throughput in short-range one-to-one communication. The ACK/NACK mechanism uses Negative ACK (NACK) as the acknowledgement policy to reduce the overhead of ACK and the transmitter switches the required acknowledgement policy to ACK based on a switchover threshold. It solves a problem arising from NACK, namely, that NACK has no mechanism for keeping alive. We evaluate the throughput of the ACK/NACK mechanism by both theoretical analysis and computer simulation. The proposed ACK/NACK mechanism is implemented in 65 nm CMOS process (BBIC); we connect this BBIC to a 60 GHz RFIC and exchange frames wirelessly. In this experiment, it is verified that the ACK/NACK mechanism enhances throughput.

  • On-Line Model Parameter Estimations for Time-Delay Systems

    Jung Hun PARK  Soohee HAN  Bokyu KWON  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E96-D No:8
      Page(s):
    1867-1870

    This paper concerns a problem of on-line model parameter estimations for multiple time-delay systems. In order to estimate unknown model parameters from measured state variables, we propose two schemes using Lyapunov's direct method, called parallel and series-parallel model estimators. It is shown through a numerical example that the proposed parallel and series-parallel model estimators can be effective when sufficiently rich inputs are applied.

  • Extreme Maximum Margin Clustering

    Chen ZHANG  ShiXiong XIA  Bing LIU  Lei ZHANG  

     
    PAPER-Artificial Intelligence, Data Mining

      Vol:
    E96-D No:8
      Page(s):
    1745-1753

    Maximum margin clustering (MMC) is a newly proposed clustering method that extends the large-margin computation of support vector machine (SVM) to unsupervised learning. Traditionally, MMC is formulated as a nonconvex integer programming problem which makes it difficult to solve. Several methods rely on reformulating and relaxing the nonconvex optimization problem as semidefinite programming (SDP) or second-order cone program (SOCP), which are computationally expensive and have difficulty handling large-scale data sets. In linear cases, by making use of the constrained concave-convex procedure (CCCP) and cutting plane algorithm, several MMC methods take linear time to converge to a local optimum, but in nonlinear cases, time complexity is still high. Since extreme learning machine (ELM) has achieved similar generalization performance at much faster learning speed than traditional SVM and LS-SVM, we propose an extreme maximum margin clustering (EMMC) algorithm based on ELM. It can perform well in nonlinear cases. Moreover, the kernel parameters of EMMC need not be tuned by means of random feature mappings. Experimental results on several real-world data sets show that EMMC performs better than traditional MMC methods, especially in handling large-scale data sets.

  • Ray-Model-Based Routing for Underwater Acoustic Sensor Networks Accounting for Anisotropic Sound Propagation

    Ping WANG  Lin ZHANG  Victor O.K. LI  

     
    PAPER-Network

      Vol:
    E96-B No:8
      Page(s):
    2060-2068

    In classical routing protocols, geographical distances/locations are typically used as the metric to select the best route, under the assumption that shorter distances exhibit lower energy consumption and nodes within the communication range of the sender can receive packets with a certain success probability. However, in underwater acoustic sensor networks (UASNs), sound propagation in the ocean medium is more complex than that in the air due to many factors, including sound speed variations and the interaction of sound waves with the sea surface and floor, causing the sound rays to bend. Therefore, propagation of sound is anisotropic in water, and may cause a phenomenon called shadow zone where nodes in the communication range of the sender cannot hear any signal. This renders conventional routing protocols no longer energy-efficient. In this paper, we make use of the ray-model to account for the environment-dependent behavior of the underwater channel, re-define nodes' one-hop neighbors based on signal attenuation rather than geographical distance, and design a distributed energy-efficient routing protocol for UASNs. Results show that our ray-model-based routing policy consistently outperforms the shortest path policy, and performs very close to the optimal one in several scenarios.

  • Sensor-Pattern-Noise Map Reconstruction in Source Camera Identification for Size-Reduced Images

    Joji WATANABE  Tadaaki HOSAKA  Takayuki HAMAMOTO  

     
    LETTER-Pattern Recognition

      Vol:
    E96-D No:8
      Page(s):
    1882-1885

    For source camera identification, we propose a method to reconstruct the sensor pattern noise map from a size-reduced query image by minimizing an objective function derived from the observation model. Our method can be applied to multiple queries, and can thus be further improved. Experiments demonstrate the superiority of the proposed method over conventional interpolation-based magnification algorithms.

  • PC Worm Detection System Based on the Correlation between User Interactions and Comprehensive Network Behaviors

    Jeongseok SEO  Sungdeok CHA  Bin ZHU  Doohwan BAE  

     
    PAPER-Information Network

      Vol:
    E96-D No:8
      Page(s):
    1716-1726

    Anomaly-based worm detection is a complement to existing signature-based worm detectors. It detects unknown worms and fills the gap between when a worm is propagated and when a signature is generated and downloaded to a signature-based worm detector. A major obstacle for its deployment to personal computers (PCs) is its high false positive alarms since a typical PC user lacks the skill to handle exceptions flagged by a detector without much knowledge of computers. In this paper, we exploit the feature of personal computers in which the user interacts with many running programs and the features combining various network characteristics. The model of a program's network behaviors is conditioned on the human interactions with the program. Our scheme automates detection of unknown worms with dramatically reduced false positive alarms while not compromising low false negatives, as proved by our experimental results from an implementation on Windows-based PCs to detect real world worms.

  • Design for Delay Measurement Aimed at Detecting Small Delay Defects on Global Routing Resources in FPGA

    Kazuteru NAMBA  Nobuhide TAKASHINA  Hideo ITO  

     
    PAPER-Test and Verification

      Vol:
    E96-D No:8
      Page(s):
    1613-1623

    Small delay defects can cause serious issues such as very short lifetime in the recent VLSI devices. Delay measurement is useful to detect small delay defects in manufacturing testing. This paper presents a design for delay measurement to detect small delay defects on global routing resources, such as double, hex and long lines, in a Xilinx Virtex 4 based FPGA. This paper also shows a measurement method using the proposed design. The proposed measurement method is based on an existing one for SoC using delay value measurement circuit (DVMC). The proposed measurement modifies the construction of configurable logic blocks (CLBs) and utilizes an on-chip DVMC newly added. The number of configurations required by the proposed measurement is 60, which is comparable to that required by stuck-at fault testing for global routing resources in FPGAs. The area overhead is low for general FPGAs, in which the area of routing resources is much larger than that of the other elements such as CLBs. The area of every modified CLB is 7% larger than an original CLB, and the area of the on-chip DVMC is 22% as large as that of an original CLB. For recent FPGAs, we can estimate that the area overhead is approximately 2% or less of the FPGAs.

  • Generation of Moire-Picture-Like Color Images by Bilateral Filter

    Toru HIRAOKA  Kiichi URAHAMA  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E96-D No:8
      Page(s):
    1862-1866

    We propose a non-photorealistic rendering method for generating moire-picture-like color images from color photographs. The proposed method is performed in two steps. First, images with a staircasing effect are generated by a bilateral filter. Second, moire patterns are generated with an improved bilateral filter called an anti-bilateral filter. The characteristic of the anti-bilateral filter is to emphasize gradual boundaries.

  • Stochastic Asymptotic Stabilizers for Deterministic Input-Affine Systems Based on Stochastic Control Lyapunov Functions

    Yuki NISHIMURA  Kanya TANAKA  Yuji WAKASA  Yuh YAMASHITA  

     
    PAPER-Systems and Control

      Vol:
    E96-A No:8
      Page(s):
    1695-1702

    In this paper, a stochastic asymptotic stabilization method is proposed for deterministic input-affine control systems, which are randomized by including Gaussian white noises in control inputs. The sufficient condition is derived for the diffusion coefficients so that there exist stochastic control Lyapunov functions for the systems. To illustrate the usefulness of the sufficient condition, the authors propose the stochastic continuous feedback law, which makes the origin of the Brockett integrator become globally asymptotically stable in probability.

  • Comparative Study on Required Bit Depth of Gamma Quantization for Digital Cinema Using Contrast and Color Difference Sensitivities

    Junji SUZUKI  Isao FURUKAWA  

     
    PAPER-Image

      Vol:
    E96-A No:8
      Page(s):
    1759-1767

    A specification for digital cinema systems which deal with movies digitally from production to delivery as well as projection on the screens is recommended by DCI (Digital Cinema Initiative), and the systems based on this specification have already been developed and installed in theaters. The parameters of the systems that play an important role in determining image quality include image resolution, quantization bit depth, color space, gamma characteristics, and data compression methods. This paper comparatively discusses a relation between required bit depth and gamma quantization using both of a human visual system for grayscale images and two color difference models for color images. The required bit depth obtained from a contrast sensitivity function against grayscale images monotonically decreases as the gamma value increases, while it has a minimum value when the gamma is 2.9 to 3.0 from both of the CIE 1976 L* a* b* and CIEDE2000 color difference models. It is also shown that the bit depth derived from the contrast sensitivity function is one bit greater than that derived from the color difference models at the gamma value of 2.6. Moreover, a comparison between the color differences computed with the CIE 1976 L* a* b* and CIEDE2000 leads to a same result from the view point of the required bit depth for digital cinema systems.

  • An Automatic Detection Method for Carotid Artery Calcifications Using Top-Hat Filter on Dental Panoramic Radiographs

    Tsuyoshi SAWAGASHIRA  Tatsuro HAYASHI  Takeshi HARA  Akitoshi KATSUMATA  Chisako MURAMATSU  Xiangrong ZHOU  Yukihiro IIDA  Kiyoji KATAGI  Hiroshi FUJITA  

     
    LETTER-Artificial Intelligence, Data Mining

      Vol:
    E96-D No:8
      Page(s):
    1878-1881

    The purpose of this study is to develop an automated scheme of carotid artery calcification (CAC) detection on dental panoramic radiographs (DPRs). The CAC is one of the indices for predicting the risk of arteriosclerosis. First, regions of interest (ROIs) that include carotid arteries are determined on the basis of inflection points of the mandibular contour. Initial CAC candidates are detected by using a grayscale top-hat filter and a simple grayscale thresholding technique. Finally, a rule-based approach and a support vector machine to reduce the number of false positive (FP) findings are applied using features such as area, location, and circularity. A hundred DPRs were used to evaluate the proposed scheme. The sensitivity for the detection of CACs was 90% with 4.3 FPs (80% with 1.9 FPs) per image. Experiments show that our computer-aided detection scheme may be useful to detect CACs.

  • Nonlinear Integer Programming Formulation for Quasi-Optimal Grouping of Clusters in Ferry-Assisted DTNs

    Masahiro SASABE  K. Habibul KABIR  Tetsuya TAKINE  

     
    PAPER-Network

      Vol:
    E96-B No:8
      Page(s):
    2076-2083

    Communication among isolated networks (clusters) in delay tolerant networks (DTNs) can be supported by a message ferry, which collects bundles from clusters and delivers them to a sink node. When there are lots of distant static clusters, multiple message ferries and sink nodes will be required. In this paper, we aim to make groups, each of which consists of physically close clusters, a sink node, and a message ferry. Our objective is minimizing the overall mean delivery delay of bundles in consideration of both the offered load of clusters and distances between clusters and their sink nodes. Based on existing work, we first model this problem as a nonlinear integer programming. Using a commercial nonlinear solver, we obtain a quasi-optimal grouping. Through numerical evaluations, we show the fundamental characteristics of grouping, the impact of location limitation of base clusters, and the relationship between delivery delay and the number of base clusters.

  • Proximity Based Object Segmentation in Natural Color Images Using the Level Set Method

    Tran Lan Anh NGUYEN  Gueesang LEE  

     
    PAPER-Image

      Vol:
    E96-A No:8
      Page(s):
    1744-1751

    Segmenting indicated objects from natural color images remains a challenging problem for researches of image processing. In this paper, a novel level set approach is presented, to address this issue. In this segmentation algorithm, a contour that lies inside a particular region of the concerned object is first initialized by a user. The level set model is then applied, to extract the object of arbitrary shape and size containing this initial region. Constrained on the position of the initial contour, our proposed framework combines two particular energy terms, namely local and global energy, in its energy functional, to control movement of the contour toward object boundaries. These energy terms are mainly based on graph partitioning active contour models and Bhattacharyya flow, respectively. Its flow describes dissimilarities, measuring correlative relationships between the region of interest and surroundings. The experimental results obtained from our image collection show that the suggested method yields accurate and good performance, or better than a number of segmentation algorithms, when applied to various natural images.

  • Efficient Hand Segmentation and Fingertip Detection Using Color Features of Skin and Fingernail

    Yaming WANG  Jiansheng CHEN  Guangda SU  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E96-D No:8
      Page(s):
    1894-1897

    In this paper, we design a new color space YUskin Vskin from YUV color space, based on the principle of skin color with respect to the change of color temperature. Compared with previous work, this color space proved to be the optimal color space for hand segmentation with linear thresholds. We also propose a novel fingertip detection method based on the concomitance between finger and fingernail. The two techniques together improve the performance of hand contour and fingertip extraction in hand gesture recognition.

  • Four-Channel Integrated Receiver with a Built-In Spatial Demultiplexer Optics for 100 Gb/s Ethernet

    Keita MOCHIZUKI  Hiroshi ARUGA  Hiromitsu ITAMOTO  Keitaro YAMAGISHI  Yuichiro HORIGUCHI  Satoshi NISHIKAWA  Ryota TAKEMURA  Masaharu NAKAJI  Atsushi SUGITATSU  

     
    PAPER

      Vol:
    E96-C No:7
      Page(s):
    981-988

    We have succeeded in demonstrating high-performance four-channel 25 Gb/s integrated receiver for 100 Gb/s Ethernet with a built-in spatial Demux optics and an integrated PD array. All components which configure to the Demux optics adhered to a prism. Because of the shaping accuracy for prism, the insertion loss was able to suppress to 0.8 dB with small size. The connection point of the package for high speed electrical signals was improved to decrease the transmission loss. The small size of 12 mm 17 mm 7 mm compact package with a side-wall electrical connector has been achieved, which is compatible with the assembly in CFP2 form-factor. We observed the sensitivity at average power of -12.1 dBm and the power penalty of sensitivity due to the crosstalk of less than 0.1 dB.

  • A Computing Method for Linear Convolution and Linear Correlation in the DCT Domain

    Izumi ITO   

     
    PAPER-Digital Signal Processing

      Vol:
    E96-A No:7
      Page(s):
    1518-1525

    We propose a computing method for linear convolution and linear correlation between sequences using discrete cosine transform (DCT). Zero-padding is considered as well as linear convolution using discrete Fourier transform (DFT). Analyzing the circular convolution between symmetrically extended sequences, we derive the condition for zero-padding before and after the sequences. The proposed method can calculate linear convolution for any filter and also calculate linear correlation without reversing one of the input sequences. The computational complexity of the proposed method is lower than that of linear convolution using DFT.

5921-5940hit(21534hit)