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

Keyword Search Result

[Keyword] CTI(8214hit)

5941-5960hit(8214hit)

  • An Algorithm for Node-Disjoint Paths in Pancake Graphs

    Yasuto SUZUKI  Keiichi KANEKO  

     
    PAPER-Algorithms

      Vol:
    E86-D No:3
      Page(s):
    610-615

    For any pair of distinct nodes in an n-pancake graph, we give an algorithm for construction of n-1 internally disjoint paths connecting the nodes in the time complexity of polynomial order of n. The length of each path obtained and the time complexity of the algorithm are estimated theoretically and verified by computer simulation.

  • ICA Papers Classified According to their Applications and Performances

    Ali MANSOUR  Mitsuru KAWAMOTO  

     
    PAPER-Reviews

      Vol:
    E86-A No:3
      Page(s):
    620-633

    Since the beginning of the last two decades, many researchers have been involved in the problem of Blind Source Separation (BSS). Whilst hundreds of algorithms have been proposed to solve BSS. These algorithms are well known as Independent Component Analysis (ICA) algorithms. Nowadays, ICA algorithms have been used to deal with various applications and they are using many performance indices. This paper is dedicated to classify the different algorithms according to their applications and performances.

  • Grey Filtering and Its Application to Speech Enhancement

    Cheng-Hsiung HSIEH  

     
    PAPER-Robust Speech Recognition and Enhancement

      Vol:
    E86-D No:3
      Page(s):
    522-533

    In this paper, a grey filtering approach based on GM(1,1) model is proposed. Then the grey filtering is applied to speech enhancement. The fundamental idea in the proposed grey filtering is to relate estimation error of GM(1,1) model to additive noise. The simulation results indicate that the additive noise can be estimated accurately by the proposed grey filtering approach with an appropriate scaling factor. Note that the spectral subtraction approach to speech enhancement is heavily dependent on the accuracy of statistics of additive noise and that the grey filtering is able to estimate additive noise appropriately. A magnitude spectral subtraction (MSS) approach for speech enhancement is proposed where the mechanism to determine the non-speech and speech portions is not required. Two examples are provided to justify the proposed MSS approach based on grey filtering. The simulation results show that the objective of speech enhancement has been achieved by the proposed MSS approach. Besides, the proposed MSS approach is compared with HFR-based approach in [4] and ZP approach in [5]. Simulation results indicate that in most of cases HFR-based and ZP approaches outperform the proposed MSS approach in SNRimp. However, the proposed MSS approach has better subjective listening quality than HFR-based and ZP approaches.

  • Speech Enhancement by Profile Fitting Method

    Osamu ICHIKAWA  Tetsuya TAKIGUCHI  Masafumi NISHIMURA  

     
    PAPER-Robust Speech Recognition and Enhancement

      Vol:
    E86-D No:3
      Page(s):
    514-521

    It is believed that distant-talking speech recognition in a noisy environment requires a large-scale microphone array. However, this cannot fit into small consumer devices. Our objective is to improve the performance with a limited number of microphones (preferably only left and right). In this paper, we focused on a profile that is the shape of the power distribution according to the beamforming direction. An observed profile can be decomposed into known profiles for directional sound sources and a non-directional background sound source. Evaluations confirmed this method reduced the CER (Character Error Ratio) for the dictation task by more than 20% compared to a conventional 2-channel Adaptive Spectral Subtraction beamformer in a non-reverberant environment.

  • 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.

  • On the Parameter Estimation of Exponentially Damped Signal in the Noisy Circumstance

    Yongmei LI  Kazunori SUGAHARA  Tomoyuki OSAKI  Ryosuke KONISHI  

     
    PAPER-Digital Signal Processing

      Vol:
    E86-A No:3
      Page(s):
    667-677

    It is well known that KT method proposed by R. Kumaresan and D. W. Tufts is used as a popular parameter estimation method of exponentially damped signal. It is based on linear backward-prediction method and singular value decomposition (SVD). However, it is difficult to estimate parameters correctly by KT method in the case when high noise exists in the signal. In this paper, we propose a parameter (frequency components and damping factors) estimation method to improve the performance of KT method under high noise. In our proposed method, we find the signal zero groups by calculating zeros with different data record lengths according to the combination of forward-prediction and backward-prediction, the mean value of the zeros in the signal zero groups are calculated to estimate the parameters of the signal. The proposed method can estimate parameters correctly and accurately even when high noise exists in the signal. Simulation results are shown to confirm the effectiveness of the proposed method.

  • Automatic Generation of Compact Electro-Thermal Models for Semiconductor Devices

    Tamara BECHTOLD  Evgenii B. RUDNYI  Jan G. KORVINK  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    459-465

    A high power dissipation density in today's miniature electronic/mechanical systems makes on-chip thermal management very important. In order to achieve quick to evaluate, yet accurate electro-thermal models, needed for the thermal management of microsystems, a model order reduction is necessary. In this paper, we present an automatic, Krylov-subspace-based order reduction of a electro-thermal model, which we illustrate by a novel type of micropropulsion device. Numerical simulation results of the full finite element model and the reduced order model, that describes the transient electro-thermal behavior, are presented. A comparison between Krylov-subspace-based order reduction, order reduction using control theoretical approaches and commercially available reduced order modeling has been performed. A Single-Input-Single-Output setup for the Arnoldi reduction algorithm was proved to be sufficient to accurately represent the complete time-dependent temperature distribution of the device.

  • Multiscale Simulation of Diffusion, Deactivation and Segregation of Boron in Silicon

    Wolfgang WINDL  

     
    INVITED PAPER

      Vol:
    E86-C No:3
      Page(s):
    269-275

    The implant-anneal cycle for B doping during Si device fabrication causes transient enhanced diffusion (TED) of B and the formation of small immobile B-interstitial clusters (BICs) which deactivate the B. Additionally, since modern ultrashallow devices put most of the B in immediate proximity of the Si/SiO2 interface, interface-dopant interactions like segregation become increasingly important. In this work, we use density-functional theory calculations to study TED, clustering, and segregation of B during annealing and discuss a continuum model which combines the TED and clustering results.

  • A New Approach to Blind System Identification in MEG Data

    Kuniharu KISHIDA  Hidekazu FUKAI  Takashi HARA  Kazuhiro SHINOSAKI  

     
    PAPER-Applications

      Vol:
    E86-A No:3
      Page(s):
    611-619

    A new blind identification method of transfer functions between variables in feedback systems is introduced for single sweep type of MEG data. The method is based on the viewpoint of stochastic/statistical inverse problems. The required conditions of the model are stationary and linear Gaussian processes. Raw MEG data of the brain activities are heavily contaminated with several noises and artifacts. The elimination of them is a crucial problem especially for the method. Usually, these noises and artifacts are removed by notch and high-pass filters which are preset automatically. In the present paper, we will try two types of more careful preprocessing procedures for the identification method to obtain impulse functions. One is a careful notch filtering and the other is a blind source separation method based on temporal structure. As results, identifiably of transfer functions and their impulse responses are improved in both cases. Transfer functions and impulse responses identified between MEG sensors are obtained by using the method in Appendix A, when eyes are closed with rest state. Some advantages of the blind source separation method are discussed.

  • Image Feature Extraction Algorithm for Support Vector Machines Using Multi-Layer Block Model

    Wonjun HWANG  Hanseok KO  

     
    PAPER-Pattern Recognition

      Vol:
    E86-D No:3
      Page(s):
    623-632

    This paper concerns recognizing 3-dimensional object using proposed multi-layer block model. In particular, we aim to achieve desirable recognition performance while restricting the computational load to a low level using 3-step feature extraction procedure. An input image is first precisely partitioned into hierarchical layers of blocks in the form of base blocks and overlapping blocks. The hierarchical blocks are merged into a matrix, with which abundant local feature information can be obtained. The local features extracted are then employed by the kernel based support vector machines in tournament for enhanced system recognition performance while keeping it to low dimensional feature space. The simulation results show that the proposed feature extraction method reduces the computational load by over 80% and preserves the stable recognition rate from varying illumination and noise conditions.

  • Establishment of Protection Paths Using Maximum Degree of Sharing in WDM Networks

    Jian-Qing LI  Hong-Shik PARK  Hyeong-Ho LEE  

     
    PAPER-Network Management/Operation

      Vol:
    E86-B No:3
      Page(s):
    1109-1116

    In wavelength division multiplexed networks, shared path protection provides the same level of protection against a single fiber-link failure as dedicated path protection with potentially higher network utilization. The shared path protection is more complex to provision and maintain. In this paper, we introduce a parameter, the degree of sharing, which refers to the number of protection paths that a wavelength can be assigned to on a link. We propose methods for calculating the maximum degree of sharing. We consider on-line routing and wavelength assignment (RWA) of protection paths that are established for incremental traffic using the maximum degree of sharing. Establishment of protection paths using the maximum degree of sharing can simplify the algorithm. We compare the results on the decreased calculation time with accepted connection requests for a given number of wavelengths, assuming that wavelengths are assigned according to the First-Fit policy for working paths and Last-Fit policy for protection paths. The more wavelengths are used, the more calculation time can be reduced. When the load increases, the decreasing rate of calculation time also increases.

  • Estimating Syntactic Structure from Prosody in Japanese Speech

    Tomoko OHSUGA  Yasuo HORIUCHI  Akira ICHIKAWA  

     
    PAPER-Speech Synthesis and Prosody

      Vol:
    E86-D No:3
      Page(s):
    558-564

    In this study, we introduce a method for estimating the syntactic structure of Japanese speech from F0 contour and pause duration. We defined a prosodic unit (PU) which is divided by the local minimal point of an F0 contour or pause. Combining PUs repeatedly (a pair of PUs is combined into one PU), a tree structure is gradually generated. Which pair of PUs in a sequence of three PUs should be combined is decided by a discriminant function based on the discriminant analysis of a corpus of speech data. We applied the method to the ATR Phonetically Balanced Sentences read by four Japanese speakers. We found that with this method, the correct rate of judgement for each sequence of three PUs is 79% and the estimation accuracy of the entire syntactic structure for each sentence is 26%. We consider this result to demonstrate a good degree of accuracy for the difficult task of estimating syntactic structure only from prosody.

  • Robust Speech Features Based on LPC Using Weighted Arcsin Transform

    Wei-Wen HUNG  

     
    LETTER-Speech and Hearing

      Vol:
    E86-D No:2
      Page(s):
    340-343

    To increase the discriminating ability of the speech feature based on linear predictive coding (LPC) and increase its noise robustness, an SNR-dependent arcsin transform is applied to the autocorrelation sequence (ACS) of each analysis frame in a speech signal. Moreover, each component in the ACS is also weighted by the normalized reciprocal of the average magnitude difference function (AMDF) for emphasizing its peak structure. Experimental results for the task of Mandarin digit recognition indicate that the LPC speech feature employing the proposed scheme is more robust than some widely used LPC-based approaches over a wide range of SNR values.

  • A Time-Optimal Distributed Arrangement Selection Algorithm in a Line Network

    Atsushi SASAKI  

     
    PAPER-Parallel/Distributed Algorithms

      Vol:
    E86-D No:2
      Page(s):
    228-237

    This paper defines the distributed arrangement selection problem in a line network in a distributed context and describes the design of a strictly-time-optimal algorithm which solves the problem with a limited local memory space. The problem is regarded as a combined distributed sorting and k-selection problem, namely a problem of sorting elements that are not larger than the kth minimum element in predetermined processes. The algorithm also provides a solution to a resource allocation problem in a line network in a strictly-optimal time.

  • Constructing a Cactus for Minimum Cuts of a Graph in O(mn+n2log n) Time and O(m) Space

    Hiroshi NAGAMOCHI  Shuji NAKAMURA  Toshimasa ISHII  

     
    PAPER-Graph Algorithms

      Vol:
    E86-D No:2
      Page(s):
    179-185

    It is known that all minimum cuts in an edge-weighted undirected graph with n vertices and m edges can be represented by a cactus with O(n) vertices and edges, a connected graph in which each edge is contained in an exactly one cycle. In this paper, we show that such a cactus representation can be computed in O(mn+n2log n) time and O(m) space. This improves the previously best complexity of deterministic cactus construction algorithms, and matches with the time bound of the fastest deterministic algorithm for computing a single minimum cut.

  • Criteria for Inductive Inference with Mind Changes and Anomalies of Recursive Real-Valued Functions

    Eiju HIROWATARI  Kouichi HIRATA  Tetsuhiro MIYAHARA  Setsuo ARIKAWA  

     
    PAPER-Computational Learning Theory

      Vol:
    E86-D No:2
      Page(s):
    219-227

    This paper investigates the interaction of mind changes and anomalies for inductive inference of recursive real-valued functions. We show that the criteria for inductive inference of recursive real-valued functions by bounding the number of mind changes and anomalies preserve the same hierarchy as that of recursive functions, if the length of each anomaly as an interval is bounded. However, we also show that, without bounding it, the hierarchy of some criteria collapses. More precisely, while the class of recursive real-valued functions inferable in the limit allowing no more than one anomaly is properly contained in the class allowing just two anomalies, the latter class coincides with the class allowing arbitrary and bounded number of anomalies.

  • A Nonlinear Model on the AQM Algorithm GREEN

    Hongwei KONG  Ning GE  Fang RUAN  Chongxi FENG  Pingyi FAN  

     
    PAPER-Packet Transmission

      Vol:
    E86-B No:2
      Page(s):
    622-629

    In this paper, we propose a nonlinear control model to characterize the AQM algorithm-GREEN. Based on this model, we analyze its performance and prove that there exists a stable oscillation when in equilibrium. Furthermore, we also investigate the effects of the factors such as bandwidth, round trip time, and load level on the amplitude and frequency of the oscillation. Theoretical analysis and simulation results indicate that GREEN algorithm is insensitive to the network conditions when the link rate and the round trip time are relatively small and becomes more sensitive to the change of network conditions when the bandwidth delay product is relatively high. For GREEN the adaptability to a wide range of network conditions is based on the compromising of the efficiency.

  • Motion Detecting Artificial Retina Model by Two-Dimensional Multi-Layered Analog Electronic Circuits

    Masashi KAWAGUCHI  Takashi JIMBO  Masayoshi UMENO  

     
    PAPER

      Vol:
    E86-A No:2
      Page(s):
    387-395

    We propose herein a motion detection artificial vision model which uses analog electronic circuits. The proposed model is comprised of four layers. The first layer is a differentiation circuit of the large CR coefficient, and the second layer is a differentiation circuit of the small CR coefficient. Thus, the speed of the movement object is detected. The third layer is a difference circuit for detecting the movement direction, and the fourth layer is a multiple circuit for detecting pure motion output. When the object moves from left to right the model outputs a positive signal, and when the object moves from right to left the model outputs a negative signal. We first designed a one-dimensional model, which we later enhanced to obtain a two-dimensional model. The model was shown to be capable of detecting a movement object in the image. Using analog electronic circuits, the number of connections decrease and real-time processing becomes feasible. In addition, the proposed model offers excellent fault tolerance. Moreover, the proposed model can be used to detect two or more objects, which is advantageous for detection in an environment in which several objects are moving in multiple directions simultaneously. Thus, the proposed model allows practical, cheap movement sensors to be realized for applications such as the measurement of road traffic volume or counting the number of pedestrians in an area. From a technological viewpoint, the proposed model facilitates clarification of the mechanism of the biomedical vision system, which should enable design and simulation by an analog electric circuit for detecting the movement and speed of objects.

  • A Realization of Multiple Circuit Transfer Functions Using OTA-C Integrator Loop Structure

    Takao TSUKUTANI  Masami HIGASHIMURA  Yasutomo KINUGASA  Yasuaki SUMI  Yutaka FUKUI  

     
    LETTER-Analog Signal Processing

      Vol:
    E86-A No:2
      Page(s):
    509-512

    This paper introduces a way to realize high-pass, band-stop and all-pass transfer functions using two-integrator loop structure consisting of loss-less and lossy integrators. The basic circuit configuration is constructed with five Operational Transconductance Amplifiers (OTAs) and two grounded capacitors. It is shown that the circuit can realize their circuit transfer functions by choosing the input terminals, and that the circuit parameters can also be independently set by the transconductance gains with the proportional block. Although the basic circuit configuration has been known, it seems that the feature for realizing the high-pass, the band-stop and the all-pass transfer functions makes the structure more attractive and useful. An example is given together with simulated results by PSPICE.

  • 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.

5941-5960hit(8214hit)