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  • Multiple k-Nearest Neighbor Classifier and Its Application to Tissue Characterization of Coronary Plaque

    Eiji UCHINO  Ryosuke KUBOTA  Takanori KOGA  Hideaki MISAWA  Noriaki SUETAKE  

     
    PAPER-Biological Engineering

      Pubricized:
    2016/04/15
      Vol:
    E99-D No:7
      Page(s):
    1920-1927

    In this paper we propose a novel classification method for the multiple k-nearest neighbor (MkNN) classifier and show its practical application to medical image processing. The proposed method performs fine classification when a pair of the spatial coordinate of the observation data in the observation space and its corresponding feature vector in the feature space is provided. The proposed MkNN classifier uses the continuity of the distribution of features of the same class not only in the feature space but also in the observation space. In order to validate the performance of the present method, it is applied to the tissue characterization problem of coronary plaque. The quantitative and qualitative validity of the proposed MkNN classifier have been confirmed by actual experiments.

  • A Similarity Study of Interactive Content-Based Image Retrieval Scheme for Classification of Breast Lesions

    Hyun-chong CHO  Lubomir HADJIISKI  Berkman SAHINER  Heang-Ping CHAN  Chintana PARAMAGUL  Mark HELVIE  Alexis V. NEES  Hyun Chin CHO  

     
    PAPER-Biological Engineering

      Pubricized:
    2016/02/29
      Vol:
    E99-D No:6
      Page(s):
    1663-1670

    To study the similarity between queries and retrieved masses, we design an interactive CBIR (Content-based Image Retrieval) CADx (Computer-aided Diagnosis) system using relevance feedback for the characterization of breast masses in ultrasound (US) images based on radiologists' visual similarity assessment. The CADx system retrieves masses that are similar to query masses from a reference library based on six computer-extracted features that describe the texture, width-to-height, and posterior shadowing of the mass. The k-NN retrieval with Euclidean distance similarity measure and the Rocchio relevance feedback algorithm (RRF) are used. To train the RRF parameters, the similarities of 1891 image pairs from 62 (31 malignant and 31 benign) masses are rated by 3 MQSA (Mammography Quality Standards Act) radiologists using a 9-point scale (9=most similar). The best RRF parameters are chosen based on 3 observer experiments. For testing, 100 independent query masses (49 malignant and 51 benign) and 121 reference masses on 230 (79 malignant and 151 benign) images were collected. Three radiologists rated the similarity between the query masses and the computer-retrieved masses. Average similarity ratings without and with RRF were 5.39 and 5.64 for the training set and 5.78 and 6.02 for the test set, respectively. Average AUC values without and with RRF were, respectively, 0.86±0.03 and 0.87±0.03 for the training set and 0.91±0.03 and 0.90±0.03 for the test set. On average, masses retrieved using the CBIR system were moderately similar to the query masses based on radiologists' similarity assessments. RRF improved the similarity of the retrieved masses.

  • Subscriber Profiling for Connection Service Providers by Considering Individuals and Different Timeframes

    Kasim OZTOPRAK  

     
    PAPER-Internet

      Vol:
    E99-B No:6
      Page(s):
    1353-1361

    Connection Service Providers (CSP) are wishing to increase their Return on Investment (ROI) by utilizing the data assets generated by tracking subscriber behaviors. This results in the ability to apply personalized policies, monitor and control the service traffic to subscribers and gain more revenue through the usage of subscriber data with ad networks. In this paper, a system is proposed to monitor and analyze the Internet access of the subscribers of a regional SP in order to classify the subscribers into interest categories from the Interactive Advertising Bureau (IAB) categories. The study employs the categorization engine to build category vectors for all individuals using Internet services through the subscription. The proposal makes it easy to detect changes in the interests of individuals/subscribers over time.

  • An Application of Laser Annealing Process in Low-Voltage Planar Power MOSFETs

    Yi CHEN  Tatsuya OKADA  Takashi NOGUCHI  

     
    BRIEF PAPER-Semiconductor Materials and Devices

      Vol:
    E99-C No:5
      Page(s):
    601-603

    An application of laser annealing process, which is used to form the shallow P-type Base junction for 20-V planar power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) is proposed. We demonstrated that the fabricated devices integrated with laser annealing process have superior electrical characteristics than those fabricated according to the standard process. Moreover, the threshold voltage variation of the devices applied by the new annealing process is effectively suppressed. This is due to that a uniform impurity distribution at the channel region is achieved by adopting laser annealing. Laser annealing technology can be applied as a reliable, effective, and advantageous process for the low-voltage power MOSFETs.

  • An Application of Laser Annealing Process in Low-Voltage Power MOSFETs

    Yi CHEN  Tatsuya OKADA  Takashi NOGUCHI  

     
    PAPER

      Vol:
    E99-C No:5
      Page(s):
    516-521

    An application of laser annealing process, which is used to form the P-type Base junction for high-performance low-voltage power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), is proposed. An equivalent shallow-junction structure for P-Base junction with uniform impurity distribution is achieved by adopting green laser annealing of pulsed mode. Higher impurity activation for the shallow junction has been achieved by the laser annealing of melted phase than by conventional RTA (Rapid Thermal Annealing) of solid phase. The application of the laser annealing technology in the fabrication process of Low-Voltage U-MOSFET is also examined.

  • Character-Position-Free On-Line Handwritten Japanese Text Recognition by Two Segmentation Methods

    Jianjuan LIANG  Bilan ZHU  Taro KUMAGAI  Masaki NAKAGAWA  

     
    PAPER-Pattern Recognition

      Pubricized:
    2016/01/06
      Vol:
    E99-D No:4
      Page(s):
    1172-1181

    The paper presents a recognition method of character-position-free on-line handwritten Japanese text patterns to allow a user to overlay characters freely without confirming previously written characters. To develop this method, we first collected text patterns written without wrist or elbow support and without visual feedback and then prepared large sets of character-position-free handwritten Japanese text patterns artificially from normally handwritten text patterns. The proposed method sets each off-stroke between real strokes as undecided and evaluates the segmentation probability by SVM model. Then, the optimal segmentation-recognition path can be effectively found by Viterbi search in the candidate lattice, combining the scores of character recognition, geometric features, linguistic context, as well as the segmentation scores by SVM classification. We test this method on variously overlaid sample patterns, as well as on the above-mentioned collected handwritten patterns, and verify that its recognition rates match those of the latest recognizer for normally handwritten horizontal Japanese text with no serious speed restriction in practical applications.

  • Distributed Compressed Video Sensing with Joint Optimization of Dictionary Learning and l1-Analysis Based Reconstruction

    Fang TIAN  Jie GUO  Bin SONG  Haixiao LIU  Hao QIN  

     
    PAPER-Image Processing and Video Processing

      Pubricized:
    2016/01/21
      Vol:
    E99-D No:4
      Page(s):
    1202-1211

    Distributed compressed video sensing (DCVS), combining advantages of compressed sensing and distributed video coding, is developed as a novel and powerful system to get an encoder with low complexity. Nevertheless, it is still unclear how to explore the method to achieve an effective video recovery through utilizing realistic signal characteristics as much as possible. Based on this, we present a novel spatiotemporal dictionary learning (DL) based reconstruction method for DCVS, where both the DL model and the l1-analysis based recovery with correlation constraints are included in the minimization problem to achieve the joint optimization of sparse representation and signal reconstruction. Besides, an alternating direction method with multipliers (ADMM) based numerical algorithm is outlined for solving the underlying optimization problem. Simulation results demonstrate that the proposed method outperforms other methods, with 0.03-4.14 dB increases in PSNR and a 0.13-15.31 dB gain for non-key frames.

  • FPGA Implementation of Various Elliptic Curve Pairings over Odd Characteristic Field with Non Supersingular Curves

    Yasuyuki NOGAMI  Hiroto KAGOTANI  Kengo IOKIBE  Hiroyuki MIYATAKE  Takashi NARITA  

     
    PAPER-Cryptography and cryptographic protocols

      Pubricized:
    2016/01/13
      Vol:
    E99-D No:4
      Page(s):
    805-815

    Pairing-based cryptography has realized a lot of innovative cryptographic applications such as attribute-based cryptography and semi homomorphic encryption. Pairing is a bilinear map constructed on a torsion group structure that is defined on a special class of elliptic curves, namely pairing-friendly curve. Pairing-friendly curves are roughly classified into supersingular and non supersingular curves. In these years, non supersingular pairing-friendly curves have been focused on from a security reason. Although non supersingular pairing-friendly curves have an ability to bridge various security levels with various parameter settings, most of software and hardware implementations tightly restrict them to achieve calculation efficiencies and avoid implementation difficulties. This paper shows an FPGA implementation that supports various parameter settings of pairings on non supersingular pairing-friendly curves for which Montgomery reduction, cyclic vector multiplication algorithm, projective coordinates, and Tate pairing have been combinatorially applied. Then, some experimental results with resource usages are shown.

  • 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.

  • Design of a Sensorless Controller Synthesized by Robust H∞ Control for Boost Converters

    Xutao LI  Minjie CHEN  Hirofumi SHINOHARA  Tsutomu YOSHIHARA  

     
    PAPER-Energy in Electronics Communications

      Vol:
    E99-B No:2
      Page(s):
    356-363

    Small loop gain and low crossover frequency result in poor dynamic performance of a single-loop output voltage controlled boost converter in continuous conduction mode. Multi-loop current control can improve the dynamic performance, however, the cost, size and weight of the circuit will also be increased. Sensorless multi-loop control solves the problems, however, the difficulty of the closed-loop characteristics evaluation will be severely aggravated, because there are more parameters in the loops, meanwhile, different from the single-loop, the relationships between the loop gains and closed-loop characteristics including audio susceptibility and output impedance are generally indirect for the multi-loop. Therefore, in this paper, a novel robust H∞ synthesis approach in the time-domain is proposed to design a sensorless controller for boost converters, which need not solve any algebraic Riccati equation or linear matrix inequalities, and most importantly, provides an approach to parameterizing the controller by an adjustable parameter. The adjustable parameter behaves like a ‘knob’ on the dynamic performance, consequently, which makes the closed-loop characteristics evaluation straightforward. A boost converter is used to verify the proposed synthesis approach. Simulations show the great convenience of the closed-loop characteristics evaluation. Practical experiments confirm the simulations.

  • Diagnosis of Stochastic Discrete Event Systems Based on N-Gram Models with Wildcard Characters

    Kunihiko HIRAISHI  Koichi KOBAYASHI  

     
    PAPER

      Vol:
    E99-A No:2
      Page(s):
    462-467

    In previous papers by the authors, a new scheme for diagnosis of stochastic discrete event systems, called sequence profiling (SP), is proposed. From given event logs, N-gram models that approximate the behavior of the target system are extracted. N-gram models are used for discovering discrepancy between observed event logs and the behavior of the system in the normal situation. However, when the target system is a distributed system consisting of several subsystems, event sequences from subsystems may be interleaved, and SP cannot separate the faulty event sequence from the interleaved sequence. In this paper, we introduce wildcard characters into event patterns. This contributes to removing the effect by subsystems which may not be related to faults.

  • Improved Primary Characteristic Basis Function Method for Monostatic Radar Cross Section Analysis of Specific Coordinate Plane

    Tai TANAKA  Yoshio INASAWA  Yasuhiro NISHIOKA  Hiroaki MIYASHITA  

     
    PAPER

      Vol:
    E99-C No:1
      Page(s):
    28-35

    The characteristic basis function method using improved primary characteristic basis functions (IP-CBFM) has been proposed as a technique for high-precision analysis of monostatic radar cross section (RCS) of a scattering field in a specific coordinate plane. IP-CBFM is a method which reduces the number of CBF necessary to express a current distribution by combining secondary CBF calculated for each block of the scatterer with the primary CBF to form a single improved primary CBF (IP-CBF). When the proposed technique was evaluated by calculating the monostatic RCS of a perfect electric conductor plate and cylinder, it was found that solutions corresponding well with analysis results from conventional CBFM can be obtained from small-scale matrix equations.

  • A Line-Direction-Free and Character-Orientation-Free On-Line Handwritten Japanese Text Recognition System

    Yuechan HAO  Bilan ZHU  Masaki NAKAGAWA  

     
    PAPER-Pattern Recognition

      Pubricized:
    2015/10/01
      Vol:
    E99-D No:1
      Page(s):
    197-207

    This paper describes a significantly improved recognition system for on-line handwritten Japanese text free from line direction and character orientation constraints. The recognition system separates handwritten text of arbitrary character orientation and line direction into text line elements, estimates and normalizes character orientation and line direction, applies two-stage over-segmentation, constructs a segmentation-recognition candidate lattice and evaluates the likelihood of candidate segmentation-recognition paths by combining the scores of character recognition, geometric features and linguistic context. Enhancements over previous systems are made in line segmentation, over-segmentation and context integration model. The results of experiments on text from the HANDS-Kondate_t_bf-2001-11 database demonstrate significant improvements in the character recognition rate compared with the previous systems. Its recognition rate on text of arbitrary character orientation and line direction is now comparable with that possible on horizontal text with normal character orientation. Moreover, its recognition speed and memory requirement do not limit the platforms or applications that employ the recognition system.

  • An Accurate Indoor-Localization Scheme with NLOS Detection and Elimination Exploiting Stochastic Characteristics

    Manato HORIBA  Eiji OKAMOTO  Toshiko SHINOHARA  Katsuhiko MATSUMURA  

     
    PAPER

      Vol:
    E98-B No:9
      Page(s):
    1758-1767

    In indoor localization using sensor networks, performance improvements are required for non-line-of-sight (NLOS) environments in which the estimation error is high. NLOS mitigation schemes involve the detection and elimination of the NLOS measurements. The iterative minimum residual (IMR) scheme, which is often applied to the localization scheme using the time of arrival (TOA), is commonly employed for this purpose. The IMR scheme is a low-complexity scheme and its NLOS detection performance is relatively high. However, when there are many NLOS nodes in a sensor field, the NLOS detection error of the IMR scheme increases and the estimation accuracy deteriorates. Therefore, we propose a new scheme that exploits coarse NLOS detection based on stochastic characteristics prior to the application of the IMR scheme to improve the localization accuracy. Improved performances were confirmed in two NLOS channel models by performing numerical simulations.

  • Comparisons on Arc Behavior and Contact Performance between Cu and Cu-Mo Alloys in a Bridge-Type Contact System

    Xue ZHOU  Mo CHEN  Guofu ZHAI  

     
    PAPER

      Vol:
    E98-C No:9
      Page(s):
    904-911

    Cu-Mo alloy carries forward not only high electrical conductivity and high thermal conductivity from Cu but also high hardness from Mo, which makes it a promising potential application in electrical contact fields. In this paper, arc characteristic and erosion characteristic of Cu-Mo contacts are studied with a bridge-type contact high speed break mechanism on DC270 V/200 A load condition. And in each experiment group, 2500 times break operations are carried out. During every break operation, a high-speed AD card is used to record voltage and current signal of the arc, a high-speed camera is applied to record arcing process, and the temperature of contacts and arc are acquired by thermocouple and spectrometer, respectively. The mass and contact resistance of contacts are measured before and after every group experiment. Besides, the photograph of contact surface is taken by SEM to help analyze the erosion characteristic. The comparison between Cu-Mo contacts and Cu contacts indicates that although Cu contacts have a better electrical conductivity and thermal conductivity, Cu-Mo contacts can decrease the temperature of arc to prevent thermal breakdown, and they are also harder to be ablated and have a longer life span.

  • Characterization of an F-Band Horn Antenna Based on Electro-Optic Near-Field Measurements

    Hai Huy NGUYEN PHAM  Shintaro HISATAKE  Tadao NAGATSUMA  

     
    PAPER-MWP Sensing Technique

      Vol:
    E98-C No:8
      Page(s):
    866-872

    We demonstrate the characterization of a horn antenna in the full F-band (90 ∼ 140 GHz) based on far-field transformation from near-field electro-optic (EO) measurement. Our nonpolarimetric self-heterodyne EO sensing system enables us to simultaneously measure the spatial distribution of the amplitude and phase of the RF signal. Because free-running lasers are used to generate and detect the RF signal, our EO sensing system has wide frequency tunability. Owing to the stable and reliable amplitude and phase measurements with minimal field perturbation, the estimated far-field patterns agree well with those of the simulated results. We have evaluated the estimation errors of the 3-dB beamwidth and position of the first sidelobe. The largest standard error of the measurements was 1.1° for 3-dB beamwidth and 3.5° for the position of first sidelobe at frequency 90 GHz. Our EO sensing system can be used to characterize and evaluate terahertz antennas for indoor communication applications such as small-size slot array antennas.

  • Balanced Boolean Functions of σƒ>22n+2n+3(n≥4)

    Yu ZHOU  Lin WANG  Weiqiong WANG  Xiaoni DU  

     
    LETTER-Cryptography and Information Security

      Vol:
    E98-A No:6
      Page(s):
    1313-1319

    The global avalanche characteristics measure the overall avalanche properties of Boolean functions, an n-variable balanced Boolean function of the sum-of-square indicator reaching σƒ=22n+2n+3 is an open problem. In this paper, we prove that there does not exist a balanced Boolean function with σƒ=22n+2n+3 for n≥4, if the hamming weight of one decomposition function belongs to the interval Q*. Some upper bounds on the order of propagation criterion of balanced Boolean functions with n (3≤n≤100) variables are given, if the number of vectors of propagation criterion is equal and less than 7·2n-3-1. Two lower bounds on the sum-of-square indicator for balanced Boolean functions with optimal autocorrelation distribution are obtained. Furthermore, the relationship between the sum-of-squares indicator and nonlinearity of balanced Boolean functions is deduced, the new nonlinearity improves the previously known nonlinearity.

  • Analysis on Non-Ideal Nonlinear Characteristics of Graphene-Based Three-Branch Nano-Junction Device

    Xiang YIN  Masaki SATO  Seiya KASAI  

     
    PAPER

      Vol:
    E98-C No:5
      Page(s):
    434-438

    We investigate the origin of non-ideal transfer characteristics in graphene-based three-branch nano-junction (TBJ) devices. Fabricated graphene TBJs often show asymmetric nonlinear voltage transfer characteristic, although symmetric one should appear ideally. A simple model considering the contact resistances in two input electrodes is deduced and it suggests that the non-ideal characteristic arises from inequality of the metal-graphene contact resistances in the inputs. We fabricate a graphene TBJ device with electrically equal contacts by optimizing the contact formation process and almost ideal nonlinear characteristic was successfully demonstrated.

  • Trace Representation over Fr of Binary Jacobi Sequences with Period pq

    Minglong QI  Shengwu XIONG  Jingling YUAN  Wenbi RAO  Luo ZHONG  

     
    LETTER-Cryptography and Information Security

      Vol:
    E98-A No:3
      Page(s):
    912-917

    In this letter, we give a trace representation of binary Jacobi sequences with period pq over an extension field of the odd prime field Fr. Our method is based on the use of a pqth root of unity over the extension field, and the representation of the Jacobi sequences by corresponding indicator functions and quadratic characters of two primes p and q.

  • A Tighter Bound for the Character Sum of Primitive Sequences over Residue Rings Modulo Square-Free Odd Integers

    Lin WANG  Yu ZHOU  Ying GAO  

     
    LETTER

      Vol:
    E98-A No:1
      Page(s):
    246-249

    Primitive linear recurring sequences over rings are important in modern communication technology, and character sums of such sequences are used to analyze their statistical properties. We obtain a new upper bound for the character sum of primitive sequences of order n over the residue ring modulo a square-free odd integer m, and thereby improve previously known bound mn/2.

61-80hit(392hit)