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

Keyword Search Result

[Keyword] Ada(1871hit)

1281-1300hit(1871hit)

  • Automatic Feature Extraction from Breast Tumor Images Using Artificial Organisms

    Hironori OKII  Takashi UOZUMI  Koichi ONO  Hong YAN  

     
    PAPER-Medical Engineering

      Vol:
    E86-D No:5
      Page(s):
    964-975

    In this paper, we propose a new computer-aided diagnosis system which can extract specific features from hematoxylin and eosin (HE)-stained breast tumor images and evaluate the type of tumor using artificial organisms. The gene of the artificial organisms is defined by three kinds of texture features, which can evaluate the specific features of the tumor region in the image. The artificial organisms move around in the image and investigate their environmental conditions during the searching process. When the target pixel is regarded as a tumor region, the organism obtains energy and produces offspring; organisms in other regions lose energy and die. The searching process is iterated until the 30th generation; as a result, tumor regions are filled with artificial organisms. Whether the detected tumor is benign or malignant is evaluated based on the combination of selected genes. The method developed was applied to 27 test cases and the distinction between benign and malignant tumors by the artificial organisms was successful in about 90% of tumor images. In this diagnosis support system, the combination of genes, which represents specific features of detected tumor region, is selected automatically for each tumor image during the searching process.

  • Advantage of the ESPRIT Method in Polarimetric Interferometry for Forest Analysis

    Koichi SATO  Hiroyoshi YAMADA  Yoshio YAMAGUCHI  

     
    PAPER-Sensing

      Vol:
    E86-B No:5
      Page(s):
    1666-1672

    Polarimetric SAR interferometry has been successful and attractive for forest parameters (tree height and canopy extinction) estimation. In this paper, we propose to use the ESPRIT algorithm to extract the interferometric phase of local scatterers with polarimetric and interferometric SAR data. Two or three local scattering waves can be extracted at each image patch when a fully polarimetric data set (HH, HV, VV) is available. Furthermore, the ESPRIT can estimate two dominant local scattering centers when only a dual polarimetric data set (e.g., VV and VH) is provided. In order to demonstrate effectiveness the proposed technqiue, we examined the relation between local scattering centers extracted by this method and complex coherence of the coherent scattering model for vegetation cover. The results show that the three-wave estimation can be more accurate than the two-wave case. The extracted interferometric phases with full and dual polarization data sets correspond to effective ground and canopy scattering centers. In this investigation, SIR-C/X-SAR data of the Tien Shan flight-pass are used.

  • Frequency Domain Active Noise Control Systems Using the Time Difference Simultaneous Perturbation Method

    Takashi MORI  Yoshinobu KAJIKAWA  Yasuo NOMURA  

     
    LETTER-Engineering Acoustics

      Vol:
    E86-A No:4
      Page(s):
    946-949

    In this letter, we propose a frequency domain active noise control system using the time difference simultaneous perturbation method. This method is an algorithm based on the simultaneous perturbation method which updates the coefficients of the noise control filter only by use of the error signal. The time difference simultaneous perturbation method updates the filter coefficients by using one kind of error signal, while the simultaneous perturbation method updates the filter coefficients by using two kinds of error signal. In the ANC systems, the time difference simultaneous perturbation method is superior because ANC systems cannot obtain two error signals at the same time. When this method is applied to ANC systems, the convergence speed can be increased to a maximum of twice that of the conventional method.

  • Improved Downlink Performance of Transmit Adaptive Array with Limited Feedback Channel Rate by Applying Transmit Antenna Selection

    Cheol Yong AHN  Dong Ku KIM  

     
    LETTER-Antenna and Propagation

      Vol:
    E86-B No:3
      Page(s):
    1186-1190

    Transmit adaptive array requires the forward link channel state for evaluating the optimum transmit weight in which a feedback channel transports the forward link channel state to the base station. Since the feedback information limits the transmission rate of the reverse link traffic, it is necessary to keep the number of feedback bits to a minimum. This paper presents a system in which the N transmit antennas are extended to the 2N transmit antennas while the feedback channel is limited as that of N-transmit antenna system. The increased antennas can give additional diversity gain but requires higher rate of feedback bits. The limited feedback channel increases the quantization error of feedback information since the number of feedback bits assigned to each antenna is reduced. In order to overcome the limited rate of feedback channel problem, this paper proposes the transmit antenna selection schemes which can effectively use the limited feedback bits, reduce the computational complexity at the mobile station, and eventually achieve diversity gain. System performances are investigated for the case of N=4 for the various antenna selection schemes on both flat fading and multi-path fading channels.

  • Continuous Speech Recognition Using an On-Line Speaker Adaptation Method Based on Automatic Speaker Clustering

    Wei ZHANG  Seiichi NAKAGAWA  

     
    PAPER-Speech and Speaker Recognition

      Vol:
    E86-D No:3
      Page(s):
    464-473

    This paper evaluates an on-line incremental speaker adaptation method for co-channel conversation including multiple speakers with the assumption that the speaker is unknown and changes frequently. After performing the speaker clustering treatment based on the Vector Quantization (VQ) distortion for every utterance, acoustic models for each cluster are adapted by Maximum Likelihood Linear Regression (MLLR) or Maximum A Posteriori probability (MAP). The performance of continuous speech recognition could be improved. In this paper, to prove the efficiency of the speaker clustering method for improving the performance of continuous speech recognition, the continuous speech recognition experiments with supervised and unsupervised cluster adaptation were conducted, respectively. Finally, evaluation experiments based on other prepared test data were performed on continuous syllable recognition and large vocabulary continuous speech recognition (LVCSR). The efficiency of the speaker adaptation and clustering methods presented in this paper was supported strongly by the experimental results.

  • TCAD Driven Drain Engineering for Hot Carrier Reduction of 3.3 V I/O PMOSFET

    Noriyuki MIURA  Hirotaka KOMATSUBARA  Marie MOCHIZUKI  Hirokazu HAYASHI  Koichi FUKUDA  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    447-452

    In this paper, we propose a TCAD driven hot carrier reduction methodology of 3.3 V I/O pMOSFETs design. The hot carrier reliability of surface channel I/O pMOSFET having drain structure in common with core devices has a critical issue. It is substantially important for the high-reliability devices to reduce both drain avalanche and channel hot hole components. The drain structures are successfully optimized in short time by applications of TCAD local models. Considering tradeoffs between hot carrier injection (HCI) and drive current (ION), SDE/HALO of both core and I/O transistors can be totally optimized for reduction of process-steps and/or photo-masks.

  • An Adaptive Beam-forming Algorithm for Smart Antenna System in Practical CDMA Environments

    Minsoo KIM  Sungsoo AHN  Seungwon CHOI  Tapan K. SARKAR  

     
    LETTER-Wireless Communication Technology

      Vol:
    E86-B No:3
      Page(s):
    1163-1169

    The objective is to generate a suboptimal weight vector for an adaptive array system operating in a multipath fading CDMA (Code Division Multiple Access) channel. The total computational load of the proposed procedure is about including the update of autocovariance matrix as well as the weight update itself, where N is the number of antenna elements. The performance of the proposed array system is shown in terms of BER (Bit Error Rate), allowable capacity, and convergence rate in practical CDMA signal environments such as IS95 and IS2000 1X.

  • An Adaptive Grid Approach for the Simulation of Electromigration Induced Void Migration

    Hajdin CERIC  Siegfried SELBERHERR  

     
    INVITED PAPER

      Vol:
    E86-C No:3
      Page(s):
    421-426

    For tracking electromigration induced evolution of voids a diffuse interface model is applied. We assume an interconnect as two-dimensional electrically conducting via which contains initially a circular void. The diffuse interface governing equation was solved applying a finite element scheme with a robust local grid adaptation algorithm. Simulations were carried out for voids exposed to high current. An influence of the void dynamics on the resistance of interconnect is investigated. In the case of the interconnect via it was shown that a migrating void exactly follows the current flow, retaining its stability, but due to change of shape and position causes significant fluctuations in interconnect resistance.

  • Adaptive Antennas Open Access

    Nobuyoshi KIKUMA  Mitoshi FUJIMOTO  

     
    INVITED PAPER

      Vol:
    E86-B No:3
      Page(s):
    968-979

    This paper reviews the historical development of adaptive antennas in Japan. First of all, we watch basic adaptive algorithms. In 1980s, particularly, the following issues were a matter of considerable concern to us; (a) behavior to the coherent interference like multipath waves or radar clutters, (b) signal degradation in case that the direction of arrival (DOA) of desired signal is different from the DOA specified beforehand in the adaptive antennas with the DOA of the desired signal as a prior knowledge, and (c) performance of adaptive antennas when the desired signal and interference are broadband. Although there are a lot of development and modification of adaptive algorithms in Japan, we refer in this paper only to the above-mentioned topics. Secondly, our attention is paid to implementation of adaptive antennas and advanced technologies. A large number of researches on the subjects have been carried out in Japan. Particularly, we focus on the initiative studies in Japan toward mobile communication application. They include researches of mobile radio propagation for adaptive antennas, calibration methods, and adaptive antenna for mobile terminals. As a matter of course, we also refer to adaptive antenna technologies for advanced communication schemes such as CDMA, SDMA, OFDM and so on. Finally, we take notice of some pilot products which were developed to verify the effect of the adaptive antenna in the practical environments. As the initiative ones, a couple of equipments are introduced in this paper.

  • Cellular and PHS Base Station Antenna Systems Open Access

    Hiroyuki ARAI  Keizo CHO  

     
    INVITED PAPER

      Vol:
    E86-B No:3
      Page(s):
    980-992

    This paper reviews the antenna system for Japanese celullar systems and PHS (Personal Handphone System). The unique features of the Japanese cellualr system are multi-band operation, compact diversity antennas, electronic beam tilting, and indoor booster systems. The original antennas for the above purpose will be described. The PHS is also a unique mobile communication system in Japan, and is mainly used for high speed, low cost data transmission. Its original antennas are also presented in this paper.

  • A Simple Configuration of Adaptive Array Antenna for DS-CDMA Systems

    Kazunari KIHIRA  Rumiko YONEZAWA  Isamu CHIBA  

     
    PAPER-Antenna and Propagation

      Vol:
    E86-B No:3
      Page(s):
    1117-1124

    An adaptive array antenna for the suppression of high-power interference in direct-sequence code-division multiple access (DS-CDMA) systems is presented. Although DS-CDMA has sufficient flexibility to support a variety of services, from voice to moving-pictures, with high levels of quality, multiple access interference (MAI) is a problem. This is particularly so of the high-power interference which accompanies high-speed transmission in DS-CDMA. While the application of adaptive array antennas is an effective way of improving signal-to-interference-plus-noise ratio (SINR), problems with this approach include large levels of power consumption and the high costs of hardware and of implementing the antennas. Therefore, our main purpose is to realize a simple configuration for an adaptive array system. In order to reduce the required amounts of processing, a common beam provides suppression of high-power interference for the low-bit-rate users; this makes per-user preparation of weights unnecessary. This approach also reduces the consumption of power by the system. Interference is cancelled by minimization of the array output power (i.e., the application of a power inversion algorithm) before despreading. The approach also allows us to improve the implementation of the antenna elements by using small auxiliary antennas. The basic performance of the system is confirmed through numerical calculation and computer simulation. Furthermore, a real-time processing unit has been developed and the effectiveness of the approach is confirmed by an experiment in a radio-anechoic chamber.

  • Full Search Based Fast Block Matching Algorithm with Efficient Matching Order in Motion Estimation

    Jong-Nam KIM  SeongChul BYUN  ByungHa AHN  

     
    LETTER-Multimedia Systems

      Vol:
    E86-B No:3
      Page(s):
    1191-1195

    In this letter we propose a new fast matching algorithm that has no degradation of predicted images such as found in the conventional full search (FS) algorithm, so as to reduce the amount of computation of the FS algorithm for motion estimation in real-time video coding applications. That is, our proposing algorithm reduces only unnecessary computations in the process of motion estimation without decreasing the prediction quality compared to the conventional FS algorithm. The computational reduction comes from rapid elimination of impossible motion vectors. In comparison to the FS algorithm, we obtained faster elimination of inappropriate candidate motion vectors using efficient matching units based on image complexity. Experimentally, we demonstrated that the unnecessary computations were removed by about 30% as compared to the other fast FS algorithms.

  • New Polynomial Construction of Jacket Transform

    Jia HOU  Moon Ho LEE  Ju Yong PARK  

     
    PAPER-Digital Signal Processing

      Vol:
    E86-A No:3
      Page(s):
    652-660

    In this paper, we present a polynomial construction based on Jacket and Hadamard matrices over the Galois Field. The construction has two modes, one only includes matrices extension, and the other includes a center-weighted scheme for polynomial representations. Here, an "addition" scheme is used to represent matrices, which can lead to simple operations and convenient implementation of hardware.

  • Speaker Recognition Using Adaptively Boosted Classifiers

    Say-Wei FOO  Eng-Guan LIM  

     
    PAPER-Speech and Speaker Recognition

      Vol:
    E86-D No:3
      Page(s):
    474-482

    In this paper, a novel approach to speaker recognition is proposed. The approach makes use of adaptive boosting (AdaBoost) and classifiers such as Multilayer Perceptrons (MLP) and C4.5 Decision Trees for closed set, text-dependent speaker recognition. The performance of the systems is assessed using a subset of utterances drawn from the YOHO speaker verification corpus. Experiments show that significant improvement in accuracy can be achieved with the application of adaptive boosting techniques. Results also reveal that an accuracy of 98.8% for speaker identification may be achieved using the adaptively boosted C4.5 system.

  • Noise and Channel Distortion Robust ASR System for DARPA SPINE2 Task

    Konstantin MARKOV  Tomoko MATSUI  Rainer GRUHN  Jinsong ZHANG  Satoshi NAKAMURA  

     
    PAPER-Robust Speech Recognition and Enhancement

      Vol:
    E86-D No:3
      Page(s):
    497-504

    This paper presents the ATR speech recognition system designed for the DARPA SPINE2 evaluation task. The system is capable of dealing with speech from highly variable, real-world noisy conditions and communication channels. A number of robust techniques are implemented, such as differential spectrum mel-scale cepstrum features, on-line MLLR adaptation, and word-level hypothesis combination, which led to a significant reduction in the word error rate.

  • A Simple Design Method of the Planar Butler Matrix Using Thin Dielectric Substrate Metalized Both Side

    Yoji ISOTA  Osami ISHIDA  Fumio TAKEDA  

     
    PAPER-Passive (Feeder)

      Vol:
    E86-C No:2
      Page(s):
    162-168

    Adaptive antenna is a promising to increase the spectral efficiency of mobile radio systems. We developed a compact, cost effective planar Butler Matrix as a beam forming network of a multi beam antenna. This circuit consists of a thin substrate that the conductor attaches to both sides, and two thick substrates that the ground conductor attaches to one side. In this circuit, coupling by crossover causes amplitude and phase error of the Butler Matrix. By narrowing the strip width of the crossover, crossover coupling can be suppressed 10 dB. The measurement results of the experimental 88 Butler Matrix were 0.75 dB amplitude deviation, 9.5 degree phase deviation and VSWR of less than 1.15 within the relative bandwidth of 10% at 900 MHz band.

  • An Equivalent MOSFET Cell Using Adaptively Biased Source-Coupled Pair

    Hiroki SATO  Akira HYOGO  Keitaro SEKINE  

     
    PAPER

      Vol:
    E86-A No:2
      Page(s):
    357-363

    The square-law characteristics of MOSFET in the saturation region have a parameter of threshold voltage VT. However, it introduces some complexities to the circuit design since it depends on kinds of MOS technology and cannot be controlled easily. In this paper, we show an equivalent MOSFET cell which has VT-programming capability and some application instances based on it. The simulation is carried out using CMOS 0.8 µm n-well technology and the results have shown the feasibility of the proposed structure.

  • A Fast Algebraic Approach to the Eigenproblems of Correlation Matrices in DOA Estimation

    Koichi ICHIGE  Masashi SHINAGAWA  Hiroyuki ARAI  

     
    LETTER-Antenna and Propagation

      Vol:
    E86-B No:2
      Page(s):
    865-869

    This paper studies on a fast approach for the eigenproblems of correlation matrices used in direction-of-arrival (DOA) estimation algorithms, especially for the case that the number of arriving waves is a few. The eigenvalues and the corresponding eigenvectors can be obtained in a very short time by the algebraic solvent of up to quartic polynomials. We also confirm that the present approach does not make the accuracy worse when it is implemented by finite word-length processors like digital signal processor (DSP) or field programmable gate array (FPGA).

  • Performance of DS-CDMA Adaptive Modulation System in a Multipath-Channel Environment

    Kazuaki TSUKAKOSHI  Toshiya KOBASHI  Yukiyoshi KAMIO  

     
    PAPER-Wireless Communication Technology

      Vol:
    E86-B No:2
      Page(s):
    743-756

    We describe a DS-CDMA adaptive modulation system in which high-rate-data for moving pictures and LANs is transmitted to a high-speed traveling mobile terminal in the down-link. The transmission data rate is constant by changing the data-modulation level and the number of multiplex channels. We use computer simulation to evaluate the performance of the system using a RAKE receiver in a multipath-channel environment. For fdTslot 0.08, which is fading maximum Doppler frequency fd normalized by slot time Tslot, the following results are obtained. The average bit error rate (BER) of BER 1 10-3 necessary to ensure quality of high-rate-data transmission for moving pictures and LANs without error correction is attainable at low symbol-to-noise power ratio of ES/N0 14 dB and channel-use rate lower than 65%. The cell capacity of 17.2% is about 1.4 times that of the conventional system. Also, fdTslot=0.08 corresponds to the traveling speed of about 250 km/h at a carrier frequency of 8 GHz. Thus, the system enables high-rate-data and high-quality transmission needed for the moving pictures and LANs at mobile terminals with a traveling speed higher than 100 km/h at high carrier frequencies of the microwave band.

  • A High-Resolution CMOS Image Sensor with Hadamard Transform Function

    Kousuke KATAYAMA  Atsushi IWATA  

     
    PAPER

      Vol:
    E86-A No:2
      Page(s):
    396-403

    This paper proposes a high-resolution CMOS image sensor, which has Hadamard transform function. This Hadamard transform circuit consists of two base generators, an array of pixel circuits, and analog-to-digital converters. In spite of simple composition, a base generator outputs a variety of bases, a pixel circuit calculates a two-dimensional base from one-dimensional bases and outputs values to common line for current addition, and analog-to-digital converter converts current value to digital value and stabilize a common line voltage for elimination of parasitic capacitance. We simulated these circuit elements and optimized using SPICE. Basic operations of this Hadamard transform circuit are also confirmed by simulation. A 256 256 pixel test chip was designed in 4.73 mm 4.73 mm area with 0.35 µm CMOS technology. A fill factor of this chip is 42% and dynamic range is 55.6 [dB]. Functions of this chip are Hadamard transform, Harr transform, projection, obtaining center of gravity, and so on.

1281-1300hit(1871hit)