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21641-21660hit(30728hit)

  • A Genetic Grey-Based Neural Networks with Wavelet Transform for Search of Optimal Codebook

    Chi-Yuan LIN  Chin-Hsing CHEN  

     
    PAPER-Neural Networks and Bioengineering

      Vol:
    E86-A No:3
      Page(s):
    715-721

    The wavelet transform (WT) has recently emerged as a powerful tool for image compression. In this paper, a new image compression technique combining the genetic algorithm (GA) and grey-based competitive learning network (GCLN) in the wavelet transform domain is proposed. In the GCLN, the grey theory is applied to a two-layer modified competitive learning network in order to generate optimal solution for VQ. In accordance with the degree of similarity measure between training vectors and codevectors, the grey relational analysis is used to measure the relationship degree among them. The GA is used in an attempt to optimize a specified objective function related to vector quantizer design. The physical processes of competition, selection and reproduction operating in populations are adopted in combination with GCLN to produce a superior genetic grey-based competitive learning network (GGCLN) for codebook design in image compression. The experimental results show that a promising codebook can be obtained using the proposed GGCLN and GGCLN with wavelet decomposition.

  • Performance of a Burst Switching Scheme for CDMA-Based Wireless Packet Data Systems

    Sung Kyung KIM  Meejoung KIM  Chung Gu KANG  

     
    PAPER-Wireless Communication Switching

      Vol:
    E86-B No:3
      Page(s):
    1082-1093

    Emerging requirements for higher rate data services and better spectrum efficiency are the main issues of third-generation mobile radio systems. In particular, a new concept of burst switching has been introduced for supporting the packet data services in the CDMA-based wireless system. In the burst switching system, radio resources are allocated to users for the duration of data bursts, which is a series of packets, as opposed to the conventional packet switching scheme. To implement the burst switching scheme, three different states (active, control hold, dormant states) are defined and two transition timers are employed to release the fundamental and supplemental code channels, respectively, at certain instances. Furthermore, the system is subject to burst admission control policy, with which a burst is admitted only when the number of currently available channels is greater than the admission threshold. Since there exists a trade-off between the additional packet access delay during a burst and resource utilization depending on the time-out value of the transition timer and burst admission threshold, it is critical to understand the performance characteristics in terms of the underlying design parameters. In this paper, we develop an analytic model and present a Quasi-Birth-Death (QBD) queueing analysis for evaluating the performance of burst switching schemes. This work focuses on the trade-off studies for optimizing the time-out value of the transition timer so as to minimize the average delay performance. Theoretical performance measures are derived by means of the matrix geometric method and furthermore, some simulation results are presented to validate the proposed analytical approach.

  • Crosstalk Equalization for High-Speed Digital Transmission Systems

    Hui-Chul WON  Gi-Hong IM  

     
    PAPER-Wireless Communication Technology

      Vol:
    E86-B No:3
      Page(s):
    1063-1072

    In this paper, we discuss crosstalk equalization technique for high-speed digital transmission systems. This equalization technique makes use of the cyclostationarity of the crosstalk interferer. We first analyze the eigenstructure of the equalizer in the presence of cyclostationary crosstalk interference. It is shown that the eigenvalues of the equalizer depend upon the folded signal and interferer power spectra, and the cross power spectrum between the signal and the interferer. The expressions of the minimum mean square error (MMSE) and the excess MSE are then obtained by using the equalizer's eigenstructure. Analysis and simulation results indicate that such peculiar equalizer's eigenstructure in the presence of cyclostationary interference results in significantly different initial convergence and steady-state behaviors as compared with the stationary noise case. We also show that the performance of the equalizer varies depending on the relative clock phase of the symbol clocks used by the signal and the crosstalk interferer.

  • Two-Particle Wave Function of Electrons Coherently Propagating along Quantum Wires

    Susanna REGGIANI  Andrea BERTONI  Massimo RUDAN  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    391-397

    A two-qubit system made of electrons running along coupled pairs of quantum wires is described and numerically analyzed. A brief review of the basic gates is given first, based on preliminary investigations, followed by the description of the electron dynamics. A detailed analysis of a conditional phase shifter is carried out by means of a time-dependent Schrodinger solver applied to a two-particle system. A quantum network suitable for creating entanglement is simulated, and results are shown. The physical structure of the proposed network is within the reach of a solid-state implementation. The physical parameters used in the computations have been chosen with reference to silicon quantum wires embedded in silicon dioxide.

  • Simulation of DGSOI MOSFETs with a Schrodinger-Poisson Based Mobility Model

    Andreas SCHENK  Andreas WETTSTEIN  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    385-390

    A TCAD implementation of a quantum-mechanical mobility model in the commercial device simulator DESSIS_ISE is presented. The model makes use of an integrated 1D Schrodinger-Poisson solver. Effective mobilities µeff and transfer characteristics are calculated for DGSOI MOSFETs with a wide range of silicon film thickness tSi and buried-oxide thickness tbox. It is shown that the volume-inversion related enhancement of µeff for tSi 10 nm is bound to symmetrical DGSOIs, whereas SIMOX based devices with thick buried oxides limit µeff to the bulk value. The still immature technology makes a conclusive comparison with experimental data impossible.

  • 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.

  • Comparative Performance Evaluation of Movement-Based Registration and Distance-Based Registration

    Byung-Han RYU  Jee-Hwan AHN  Jang-Hyun BAEK  

     
    LETTER-Terrestrial Radio Communications

      Vol:
    E86-B No:3
      Page(s):
    1177-1180

    In this study, we consider movement-based registration (MBR), improved MBR (IMBR) and distance-based registration (DBR). Analytical models based on 2-dimensional random walk in hexagonal cell configuration are considered to analyze the performance of MBR/IMBR and DBR. Especially, we focus on the derivation of the registration cost of DBR scheme by using analytical method and then show that DBR always outperforms not only MBR but also IMBR.

  • Application of the Alternating-Direction Implicit FDTD Method for Analyzing the Power Plane Resonance Problem

    Jeongnam CHEON  Hyunsik PARK  Hyeongdong KIM  

     
    LETTER-Antenna and Propagation

      Vol:
    E86-B No:3
      Page(s):
    1181-1185

    In this paper, the power plane resonance problem in a multi-layered PCB is numerically analyzed by applying the alternating-direction implicit (ADI) FDTD method. This method is extremely suitable for analyzing the power plane resonance problems having locally fine structures of two closely located planes. This paper also analyzes the effect of the decoupling capacitor, which is one of the solutions for reducing the resonance problem. The results of the ADI-FDTD agree well with those of the conventional FDTD and the analytic solutions, and the computational CPU time is reduced to about a half of that of the conventional FDTD.

  • Blind Separation of Independent Sources from Convolutive Mixtures

    Pierre COMON  Ludwig ROTA  

     
    INVITED PAPER-Convolutive Systems

      Vol:
    E86-A No:3
      Page(s):
    542-549

    The problem of separating blindly independent sources from a convolutive mixture cannot be addressed in its widest generality without resorting to statistics of order higher than two. The core of the problem is in fact to identify the paraunitary part of the mixture, which is addressed in this paper. With this goal, a family of statistical contrast is first defined. Then it is shown that the problem reduces to a Partial Approximate Joint Diagonalization (PAJOD) of several cumulant matrices. Then, a numerical algorithm is devised, which works block-wise, and sweeps all the output pairs. Computer simulations show the good behavior of the algorithm in terms of Symbol Error Rates, even on very short data blocks.

  • The Extraction of Vehicle License Plate Region Using Edge Directional Properties of Wavelet Subband

    Sung Wook PARK  Su Cheol HWANG  Jong Wook PARK  

     
    LETTER-Image Processing, Image Pattern Recognition

      Vol:
    E86-D No:3
      Page(s):
    664-669

    Changing vehicle structures and backgrounds makes it very difficult to correctly extract a license plate region from a vehicle image. In this paper, we propose a simple method to extract the license plate region using edge properties of wavelet subband. The High Frequency Subband (HFS) of an image has edge information for each direction. Edge information is concentrated in each direction of the Headlight-Radiator-Headlight (H-R-H) and the license plate region compared to other regions in the vehicle image. This paper shows a license plate region extraction method using these edge properties and our experimental results with various vehicle images.

  • 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.

  • Scheduling for a Large-Scale Production System Based on a Continuous and Timed Petri-Net Model

    YoungWoo KIM  Akio INABA  Tatsuya SUZUKI  Shigeru OKUMA  

     
    PAPER-Theory/Models of Computation

      Vol:
    E86-D No:3
      Page(s):
    583-593

    This paper presents a new hierarchical scheduling method for a large-scale manufacturing system based on the hybrid Petri-net model, which consists of CPN (Continuous Petri Net) and TPN (Timed Petri Net). The study focuses on an automobile production system, a typical large-scale manufacturing system. At a high level, CPN is used to represent continuous flow in the production process of an entire system, and LP (Linear Programming) is applied to find the optimal flow. At a low level, TPN is used to represent the manufacturing environment of each sub-production line in a decentralized manner, and the MCT algorithm is applied to find feasible semi-optimal process sequences for each sub-production line. Our proposed scheduling method can schedule macroscopically the flow of an entire system while considering microscopically any physical constraints that arise on an actual shop floor.

  • A Novel CDM-Like Discharge Effect during Human Body Model (HBM) ESD Stress

    Valery AXELRAD  Yoon HUH  Jau-Wen CHEN  Peter BENDIX  

     
    INVITED PAPER

      Vol:
    E86-C No:3
      Page(s):
    398-403

    Interactions between ESD protection devices and other components of a chip can lead to complex and not easily anticipated discharge bevahior. Triggering of a protection MOSFET is equivalent to the closing of a fast switch and can cause substantial transient discharge currents. The peak value of this current depends on the chip capacitance, resistance, properties of the protection clamp, etc. Careful optimization of the protection circuit is therefore necessary to avoid current overstress and circuit failure.

  • Quantum Electron Transport Modeling in Nano-Scale Devices

    Matsuto OGAWA  Hideaki TSUCHIYA  Tanroku MIYOSHI  

     
    INVITED PAPER

      Vol:
    E86-C No:3
      Page(s):
    363-371

    We describe progress we have achieved in the development of our quantum transport modeling for nano-scale devices. Our simulation is based upon either the non-equilibrium Green's function method (NEGF) or the quantum correction (QC) associated with density gradient method (DG) and/or effective potential method (EP). We show the results of our modeling methods applied to several devices and discuss issues faced with regards to computational time, open boundary conditions, and their relationship to self-consistent solution of the Poisson-NEGF equations. We also discuss those for efficiently tailored QC Monte Carlo techniques.

  • Three-Dimensional Triangle-Based Simulation of Etching Processes and Applications

    Oliver LENHART  Eberhard BAR  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    427-432

    A software module for the three-dimensional simulation of etching processes has been developed. It works on multilayer structures given as triangulated surface meshes. The mesh is moved nodewise according to rates which, in this work, have been determined from isotropic and anisotropic components. An important feature of the algorithm is the automatic detection of triple lines along mask edges and the refinement of triangles at these triple lines. This allows for the simulation of underetching. The capabilities of the algorithm are demonstrated by several examples such as the simulation of glass etching for the fabrication of a phase shift mask for optical lithography and the etching of an STI trench structure. Moreover, etch profiles of a silicon substrate covered by an oxide mask are shown for different parameters of the etch components. Spacer etching has also been performed. Furthermore, a specific algorithm for the simulation of purely isotropic etching is described and demonstrated.

  • Music Style Mining and Classification by Melody

    Man-Kwan SHAN  Fang-Fei KUO  

     
    LETTER-Speech and Hearing

      Vol:
    E86-D No:3
      Page(s):
    655-659

    Music style is one of the features that people used to classify music. Discovery of music style is helpful for the design of content-based music retrieval systems. In this paper we investigated the mining and classification of music style by melody from a collection of MIDI music. We extracted the chord from the melody and investigated the representation of extracted features and corresponding mining techniques for music classification. Experimental results show that the classification achieved 64% to 84% accuracy for two-way classification.

  • Statistical Threshold Voltage Fluctuation Analysis by Monte Carlo Ion Implantation Method

    Yoshinori ODA  Yasuyuki OHKURA  Kaina SUZUKI  Sanae ITO  Hirotaka AMAKAWA  Kenji NISHI  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    416-420

    A new analysis method for random dopant induced threshold voltage fluctuations by using Monte Carlo ion implantation were presented. The method was applied to investigate Vt fluctuations due to statistical variation of pocket dopant profile in 0.1µm MOSFET's by 3D process-device simulation system. This method is very useful to analyze a statistical fluctuation in sub-100 nm MOSFET's efficiently.

  • Simulation Technique of Heating by Contact Resistance for ESD Protection Device

    Kazuya MATSUZAWA  Hirobumi KAWASHIMA  Toyoaki MATSUHASHI  Naoyuki SHIGYO  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    404-408

    The potential drop and the self-heating due to the contact resistance at the interface between silicide and silicon are incorporated in the device simulation for ESD protection devices. A transition region is provided at the interface and the resistivity is calculated by scaling the contact resistance by the length of the region. The power density used in the heat conductive equation is calculated by using the potential drop and the contact resistance in the transition region. The validity of the present approach is checked by the Monte Carlo simulations. Using the technique, influence of the contact resistance on self-heating in an ESD protection device with the grounded gate MOSFET structure is simulated.

  • On Density-Gradient Modeling of Tunneling through Insulators

    Timm HOHR  Andreas SCHENK  Andreas WETTSTEIN  Wolfgang FICHTNER  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    379-384

    The density gradient (DG) model is tested for its ability to describe tunneling currents through thin insulating barriers. Simulations of single barriers (MOS diodes, MOSFETs) and double barriers (RTDs) show the limitations of the DG model. For comparison, direct tunneling currents are calculated with the Schrodinger-Bardeen method and used as benchmark. The negative differential resistance (NDR) observed in simulating tunneling currents with the DG model turns out to be an artifact related to large density differences in the semiconductor regions. Such spurious NDR occurs both for single and double barriers and vanishes, if all semiconductor regions are equally doped.

  • Investigation of the Electron Mobility in Strained Si1-xGex at High Ge Composition

    Sergey SMIRNOV  Hans KOSINA  Siegfried SELBERHERR  

     
    PAPER

      Vol:
    E86-C No:3
      Page(s):
    350-356

    Monte Carlo simulation of the low field electron mobility of strained Si and SiGe active layers on Si and SiGe substrates is considered. The Ge mole fractions of both the active layer and the substrate are varied in a wide range. The linear deformation potential theory is used to calculate the shifts of the conduction band minima due to uniaxial strain along [001]. The energy shifts and the effective masses are assumed to be functions of the Ge mole fraction. It is shown that in spite of the fact that the L-valleys remain degenerate under strain conditions considered here, they play an important role at very high Ge compositions especially when SiGe as substrate is used. We found that in this case the repopulation effects of the X-valleys affect electron mobility much stronger than the alloy scattering. We also generalize the ionized impurity scattering rate to include strain effects for doped materials and show that some of the important parameters such as effective density of states, inverse screening length, and the screening function are split due to strain and must be properly modified. Finally, we perform several simulations for undoped and doped materials using Si and SiGe substrates.

21641-21660hit(30728hit)