Tạp chí Phát triển Khoa học & Công nghệ ĐHQG-HCM

  • A 6-bit Low-Power High-Speed Flash ADC using 180 nm CMOS process

    0 trên 5

    In this paper we present a design of
    Flash-ADC that can achieve high
    performance and low power consumption.
    By using the Double Sampling Rate
    technique and a new comparator topology
    with low kick-back noise, this design can
    achieve high sampling rate while still
    consuming low power. The design is
    implemented in a 0.18 m CMOS process.
    The simulation results show that this design
    can work at 400 MSps and power
    consumption is only 16.24 mW. The DNL
    and INL are 0.15 LSB and 0.6 LSB,
    respectively.

    5 ePoint
  • A consecutive-interpolation finite element method for heat transfer analysis

    0 trên 5

    A consecutive-interpolation 4-node
    quadrilateral finite element (CQ4) is
    further extended to solve twodimensional heat transfer problems,
    taking the average nodal gradients as
    interpolation condition, resulting in highorder continuity solution without
    smoothing operation and without
    increasing the number of degrees of
    freedom. The implementation is
    straightforward and can be easily
    integrated into any existing FEM code.
    Several numerical examples are
    investigated to verify the accuracy and
    efficiency of the proposed formulation in
    two-dimensional heat transfer analysis.

    5 ePoint
  • A Design of 10-b 100-MS/s Pipelined Folding ADC with Distributed Trackand- Hold Preprocessing

    0 trên 5

    This paper presents a 10-b ADC
    designed in a 0.18-μm CMOS technology.
    The ADC achieves 10-b resolution by using
    the cascaded folding technique in both the
    fine and coarse converters. Folding stages
    are pipelined to improve the settling time. As
    a result, this ADC can achieve the sampling
    rate up to 100MS/s. Moreover, instead of
    using a costly single track-and-hold circuit, a
    distributed track-and-hold circuit is used to
    reduce the chip area and the power
    consumption. This also allows utilizing the
    open-loop architecture of the folding
    technique, thus improving the performance
    of the system. The simulation results show
    that with a 49 MHz sine-wave input, the ADC
    consumes 66 mW and the effective number
    of bit (ENOB) is 9.28-b. Taking into account
    of process variations by using a Monte Carlo
    simulation, the DNL varies from ±0.45LSB to
    ±0.25LSB. The layout of the ADC occupies
    1.2 mm2 die area.

    5 ePoint
  • A method of sliding mode control of cart and pole system

    0 trên 5

    This paper presents a method of using
    Sliding Mode Control (SMC) for Cart and Pole
    system. The stability of controller is proved
    through using Lyapunov function and
    simulations. A genetic algorithm (GA)
    program is used to optimize controlling
    parameters. The GA-based parameters
    prove good-quality of control through
    Matlab/Simulink Simulation.

    5 ePoint
  • A Modified Semi-parametric Regression Model For Flood Forecasting

    0 trên 5

    In recent years, inundation, one of
    natural calamities, occurs frequently and
    fiercely. We are sustained severe losses
    in the floods every year. Therefore, the
    development of control methods to
    determine, analyze, model and predict
    the floods is indispensable and urgent. In
    this paper, we propose a justified semiparametric regression model for flood
    water levels forecasting. The new model
    has three components. The first one is
    parametric elements of the model. They
    are water level, precipitation,
    evaporation, air-humidity and groundmoisture values, etc. There is a complex
    connection among these parametrics.
    Several innovated regression models
    have been offered and experimented for
    this complicated relationship. The
    second one is a non-parametric
    ingredient of our model. We use the
    Arnak S. Dalalyan et al.’s effective
    dimension-reduction subspace algorithm
    and some modified algorithms in neural
    networks to deal with it. They are altered
    back-propagation method and
    ameliorated cascade correlation
    algorithm. Besides, we also propose a
    new idea to modify the conjugate
    gradient one. These actions will help us
    to smooth the model’s non-parametric
    constituent easily and quickly. The last
    component is the model’s error. The
    whole elements are essential inputs to
    operational flood management. This
    work is usually very complex owing to
    the uncertain and unpredictable nature of
    underlying phenomena. Flood-waterlevels forecasting, with a lead time of
    one and more days, was made using a
    selected sequence of past water-level
    values observed at a specific location.
    Time-series analytical method is also
    utilized to build the model. The results
    obtained indicate that, with a new semiparametric regression one and the
    effective dimension-reduction subspace
    algorithm, together with some improved
    algorithms in neural network, the
    estimation power of the modern
    statistical model is reliable and
    auspicious, especially for flood
    forecasting/modeling.

    5 ePoint
  • A new method of electrodes placement to improve QRS detection in real-time stress ECG acquisition

    0 trên 5

    In dynamic threshold method to
    detect QRS complex from ECG signal,
    especially in real-time application, there
    are two main issues: baseline drift and
    noise. This paper introduces an
    improved QRS complex detecting
    method using dynamic threshold
    algorithm combined with a new method
    of electrodes placement to minimize
    baseline drift and different types of noise
    in real-time ECG acquisition with moving
    patients. Our method proved to be more
    effective in detecting QRS complex with
    less error due to minimized baseline drift
    and noise in original ECG signal.

    5 ePoint
  • A sliding mode algorithm for antilock braking/traction control of EVs

    0 trên 5

    This paper presents a slip suppression
    controller using sliding mode control method
    for electric vehicles which aims to improve
    the control performance of Evs in both driving
    and braking mode. In this method, a sliding
    mode controller is designed to obtain the
    maximum driving force by suppressing the
    slip ratio. The numerical simulations for one
    wheel model under variations in mass of
    vehicle and road condition are performed and
    demonstrated to show the effectiveness of
    the proposed method.

    5 ePoint
  • Accurate motion regeneration technique with robust control approach

    0 trên 5

    In this paper, the authors propose a new
    method of easily recognizing and
    regenerating robot motions used for robot
    motion control to perform the task of painting
    furniture and welding parts in small scale
    industries. The method is based on the
    process of accurate modeling, control design
    and experimental evaluation. In this study,
    the models and controllers for all joints of
    3DOF robot system are obtained individually.
    The Robust control controller is designed to
    cope with uncertainties, especially the effects
    of the added inertia moment. In the
    experiment, the robust control method is
    compared with the existing PID control
    method, and the results indicate that the
    proposed designing method is more efficient
    than the traditional method.

    5 ePoint
  • An application of genetic algorithm to optimize the 3-Joint carangiform fish robot’ s links to get the desired straight velocity

    0 trên 5

    Biomimetic robot is a new branch of
    researched field which is developing
    quickly in recent years. Some of the
    popular biomimetic robots are fish robot,
    snake robot, dog robot, dragonfly robot,
    etc. Among the biomimetic underwater
    robots, fish robot and snake robot are
    mostly concerned. In this paper, we
    study about an optimization method to
    find the design parameters of fish robot.
    First, we analyze the dynamic model of
    the 3-joint Carangiform fish robot by
    using Lagrange method. Then the
    Genetic Algorithm (GA) is used to find
    the optimal lengths’ values of fish
    robot’s links. The constraint of this
    optimization problem is that the values of
    fish robot’s links are chosen that they
    can make fish robot swim with the
    desired straight velocity. Finally, some
    simulation results are presented to prove
    the effectiveness of the proposed
    method.

    5 ePoint
  • An efficient hardware architecture for HMM-based TTS system

    0 trên 5

    This work proposes a hardware
    architecture for HMM-based text-to-speech
    synthesis system (HTS). In high speed
    platforms, HTS with software core-engine
    can satisfy the requirement of real-time
    processing. However, in low speed
    platforms, software core-engine consumes
    long time-cost to complete the synthesis
    process. A co-processor was designed and
    integrated into HTS to accelerate the
    performance of system.

    5 ePoint
  • An improved radial point interpolation method applied for elastic problem with functionally graded material

    0 trên 5

    A meshless method based on radial
    point interpolation was developed as an
    effective tool for solving partial
    differential equations, and has been
    widely applied to a number of different
    problems. Besides its advantages, in this
    paper we introduce a new way to
    improve the speed and time calculations,
    by construction and evaluation the
    support domain. From the analysis of
    two-dimensional thin plates with different
    profiles, structured conventional isotropic
    materials and functional graded
    materials (FGM), the results are
    compared with the results had done
    before that indicates: on the one hand
    shows the accuracy when using the new
    way, on the other hand shows the time
    count as more economical.

    5 ePoint
  • An interaction integral method for evaluating T-stress for two-dimensional crack problems using the extended radial point interpolation method

    0 trên 5

    The so-called T-stress, or second
    term of the William (1957) series
    expansion for linear elastic crack-tip
    fields, has found many uses in fracture
    mechanics applications. In this paper, an
    interaction integral method for calculating
    the T-stress for two-dimensional crack
    problems using the extended radial point
    interpolation method (XRPIM) is
    presented. Typical advantages of RPIM
    shape function are the satisfactions of
    the Kronecker’s delta property and the
    high-order continuity. The T-stress can
    be calculated directly from a path
    independent interaction integral entirely
    based on the J-integral by simply the
    auxiliary field. Several benchmark
    examples in 2D crack problem are
    performed and compared with other
    existing solutions to illustrate the
    correction of the presented approach.

    5 ePoint
  • An isogeometric analysis approach for twodimensional steady state heat transfer problems

    0 trên 5

    The purpose of this article is studied
    the application of isogeometric analysis
    (IGA) to two-dimensional steady state
    heat transfer problems in a heat sink. By
    using high order basis functions, NURBS
    basis functions, IGA is a high rate
    convergence approach in comparison to
    a traditional Finite Element Method.
    Moreover, the development of this
    method decreased the gaps between
    CAD and mathematical model and
    increased the continuity of mesh.

    5 ePoint
  • Analyzing event related potentials using adaptive filter

    0 trên 5

    ERPs (Event Related Potentials) are
    EEG signals which are directly measured
    from cortical electrical response to
    external stimuli such as feelings, sensual
    or cognitive events. The evaluation of the
    amplitude and latency of the ERP wave
    has important significance in evaluating
    neurological reflex. However, the ERP
    wave amplitude is small compared with
    the EEG wave, and considerably
    affected by the noise such as eyes,
    muscles, heart motion etc. In this paper,
    datasets are collected from ERPLAB and
    journals provided available datasets with
    the stimulus of sound and light. Using
    adaptive noise cancellation (ANC)
    combined with LMS algorithm the waves
    P300 of ERP were detected and
    separated. The algorithm was evaluated
    by the ratio SNR and average value.
    Results were compared with other
    published tools such as P300 calculation
    algorithm of ERPLAB softwar.

    5 ePoint
  • Analyzing the impact of wind generation on the transient stability

    0 trên 5

    The wind generation causes some
    troubles on the stability of power network.
    Observing the critical clearing time of circuit
    breaker with existence of wind generation,
    one conclusion about the degrading of
    stability will be drawn. The location and the
    penetration level of this generation are also
    considered in this paper. The 14 buses IEEE
    network is examined with the soft ware
    PSAT.

    5 ePoint
  • Ảnh hưởng của hư hỏng lên phổ dao động của dầm chịu tác dụng của tải di động

    0 trên 5

    Bài báo khảo sát những thay đổi các giá
    trị của phổ công suất tín hiệu dao động ngẫu
    nhiên của một cấu trúc dầm chịu tác dụng
    của tải di động khi hư hỏng xuất hiện. Từ đó
    trình bày một phương pháp khảo sát ứng xử
    của dầm cầu đã bị suy yếu. Sự suy yếu của
    dầm được thực hiện bằng cách thay đổi độ
    cứng chống uốn của dầm (tạo vết cắt doc
    hay ngang). Những đặc trưng trích xuất từ
    thay đổi giá trị của phổ công suất được dùng
    để nhận dạng hư hỏng. Phương pháp kiểm
    chứng được thực hiện dựa trên các tập số
    liệu đo trên một thanh dầm kim loại dao động
    với tải trọng di chuyển. Thí nghiệm được
    thực hiện tại Phòng thí nghiệm Cơ học ứng
    dụng (PTN CHUD) của trường Đại học Bách
    khoa Tp.HCM. Phổ dao động được tính toán
    từ tín hiệu của các cảm biến gia tốc kiểu
    MEMS bố trí cách đều dọc trên dầm.

    5 ePoint
  • ẢNH HƯỞNG CỦA LÝ DO GIẢI THÍCH THÁI ĐỘ ĐẾN MỨC ĐỘ TIÊU DÙNG CÁC SẢN PHẨM CÁ

    0 trên 5

    Bài báo này khám phá các lý do giải thích cho thái độ, cũng như ảnh hưởng ca chúng lên hành
    vi và sự tương thích giữa thái độ và hành vi của người tiêu dùng đối vi các sn phm cá. Da trên mu
    361 người tiêu dùng tnh Khánh Hòa, phân tích thng kê mô tvà hồi quy được sdụng để đáp ứng
    mc tiêu nghiên cu. Kết quchra rng, trong khi các yếu tchất lượng dinh dưỡng và khu vchiếm
    tlln nht giải thích cho các thái độ tích cc, thì các yếu tchất lượng vsinh an toàn thc phm,
    xương cá, mùi tanh, chất bn và vy cá li chiếm ttrng ni tri giải thích cho các thái độ tiêu cc.
    Hơn nữa, những người tiêu dùng có nhiều lý do hơn giải thích cho thái độ tích cc ca h, thì mức độ
    tiêu dùng cũng như sự tương thích giữa thái độ và hành vi tiêu dùng ca họ là cao hơn. Ngược li,
    những người tiêu dùng có nhiều lý do hơn giải thích cho thái độ tiêu cc, thì mức độ tiêu dùng là thp
    hơn, nhưng không ảnh hưởng đến sự tương thích giữa thái độ và hành vi tiêu dùng ca h. Kết qunày
    vì vy là quan trng cho những người kinh doanh cá để gia tăng mức mua hàng của người tiêu dùng.

    5 ePoint
  • Ảnh hưởng của N, P, K, cytokinin và stress nước lên thời gian ra hoa của Dendrobium Sonia

    0 trên 5

    Lan Dendrobium sonia thường được sử dụng như hoa cắt cành và trồng trong chậu do màu sắc đẹp tuy nhiên quá trình tăng trưởng thường kéo dài 13 tháng sau khi được trồng ngoài vườn. Các tỷ lệ N: P: K khác nhau, kết hợp với benzyladenin (BA) và ngưng tưới nước được khảo sát để rút ngắn thời gian ra hoa của Dendrobium sonia. Những cây lan sau khi trồng 6 tháng với nền phân bón (PB) N,P,K theo nồng độ tăng P có thể rút ngắn thời gian ra hoa nhưng sớm hơn đối chứng không nhiều. Với nền phân có chứa 50 mg/N, 100 mg/l P, 50 mg/l K kết hợp phun 100 mg/L BA cây lan cho chồi hoa sớm (sau 30 ngày xử lý) tuy nhiên tỷ lệ cây mang chồi hoa thấp (20 %). Với nền phân có chứa 50 mg/N, 100 mg/l P, 50 mg/l K, kết hợp xử lý ngưng tưới nước 2 tuần và phun 100 mg/L BA, cây ra hoa sớm (sau 30 ngày xử lý) và tỷ lệ cây mang chồi hoa cao (73,3 %). Những cây đối chứng phun N, P, K theo nồng độ 50 mg/L N, 100 mg/l P, 50 mg/L K chcho 13,3 % chồi hoa sau 120 ngày xử lý.

    5 ePoint