• Title/Summary/Keyword: zero-error

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Predictive and Preventive Maintenance using Distributed Control on LonWorks/IP Network

  • Song, Ki-Won
    • International Journal of Safety
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    • v.5 no.2
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    • pp.6-11
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    • 2006
  • The time delay in servo control on LonWorks/IP Virtual Device Network (VDN) is highly stochastic in nature. LonWorks/IP VDN induced time delay deteriorates the performance and stability of the real-time distributed control system and hinders an effective preventive and predictive maintenance. Especially in real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. In order to guarantee the stability and performance of the system for effective preventive and predictive maintenance, LonWorks/IP VDN induced time delay needs to be predicted and compensated for. In this paper position control simulation of DC servo motor using Zero Phase Error Tracking Controller (ZPETC) as a feedforward controller, and Internal Model Controllers (IMC) based on Smith predictor with disturbance observer as a feedback controller is performed. The validity of the proposed control scheme is demonstrated by comparing the IMC based on Smith predictor with disturbance observer.

Spatial Multiplexing Receivers in UWB MIMO Systems based on Prerake Combining

  • An, Jin-Young;Kim, Sang-Choon
    • Journal of information and communication convergence engineering
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    • v.9 no.4
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    • pp.385-390
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    • 2011
  • In this paper, various ultra-wideband (UWB) spatial multiplxing (SM) multiple input multiple output (MIMO) receivers based on a prerake diversity combining scheme are discussed and their performance is analyzed. Several UWB MIMO detection approaches such as zero forcing (ZF), minimum mean square error (MMSE), ordered successive interference cancellation (OSIC), sorted QR decomposition (SQRD), and maximum likelihood (ML) are considered in order to cope with inter-channel interference. The UWB SM systems based on transmitter-side multipath preprocessing and receiver-side MIMO detection can either boost the transmission data rate or offer significant diversity gain and improved BER performance. The error performance and complexity of linear and nonlinear detection algorithms are comparatively studied on a lognormal multipath fading channel.

A Detection and Isolation Scheme for Nonlinear Systems with a Actuator and Sensor Faults (비선형 시스템의 액츄에이터 고장과 센서 고장을 위한 감지 및 분리 기법)

  • Han, Byung-Jo;Hwang, Young-Ho;Kim, Hong-Pil;Yang, Hai-Won
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1724-1725
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    • 2007
  • This paper presents a fault detection and isolation(FDI) scheme for a nonlinear systems with a actuator and sensor faults. A residual generator based on the observer model generate the information for a fault detection. The proposed fault estimators are activated for a fault isolation and applied to estimate the time-varying lumped faults(model uncertainty + fault). but a fault estimator error dose not converge to zero since the derivative of lumped fault is not zero. Then the fuzzy neural network(FNN) is used to estimate the fault estimator error. Simulation results are presented to illustrate the effectiveness and the applicability of the approaches proposed.

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A THIRD-ORDER VARIANT OF NEWTON-SECANT METHOD FINDING A MULTIPLE ZERO

  • Kim, Young Ik;Lee, Sang Deok
    • Journal of the Chungcheong Mathematical Society
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    • v.23 no.4
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    • pp.845-852
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    • 2010
  • A nonlinear algebraic equation f(x) = 0 is considered to find a root with integer multiplicity $m{\geq}1$. A variant of Newton-secant method for a multiple root is proposed below: for n = 0, 1, $2{\cdots}$ $$x_{n+1}=x_n-\frac{f(x_n)^2}{f^{\prime}(x_n)\{f(x_n)-{\lambda}f(x_n-\frac{f(x_n)}{f^{\prime}(x_n)})\}$$, $$\lambda=\{_{1,\;if\;m=1.}^{(\frac{m}{m-1})^{m-1},\;if\;m{\geq}2$$ It is shown that the method has third-order convergence and its asymptotic error constant is expressed in terms of m. Numerical examples successfully verified the proposed scheme with high-precision Mathematica programming.

Diminution of Current Measurement Error in Vector Controlled AC Motor Drives

  • Jung Han-Su;Kim Jang-Mok;Kim Cheul-U;Choi Cheol;Jung Tae-Uk
    • Journal of Power Electronics
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    • v.5 no.2
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    • pp.151-159
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    • 2005
  • The errors generated from current measurement paths are inevitable, and they can be divided into two categories: offset error and scaling error. The current data including these errors cause periodic speed ripples which are one and two times the stator electrical frequency respectively. Since these undesirable ripples bring about harmful influences to motor driving systems, a compensation algorithm must be introduced to the control algorithm of the motor drive. In this paper, a new compensation algorithm is proposed. The signal of the integrator output of the d-axis current regulator is chosen and processed to compensate for the current measurement errors. Usually the d-axis current command is zero or constant to acquire the maximum torque or unity power factor in the ac drive system, and the output of the d-axis current regulator is nearly zero or constant as well. If the stator currents include the offset and scaling errors, the respective motor speed produces a ripple related to one and two times the stator electrical frequency, and the signal of the integrator output of the d-axis current regulator also produces the ripple as the motor speed does. The compensation of the current measurement errors is easily implemented to smooth the signal of the integrator output of the d-axis current regulator by subtracting the DC offset value or rescaling the gain of the hall sensor. Therefore, the proposed algorithm has several features: the robustness in the variation of the mechanical parameters, the application of the steady and transient state, the ease of implementation, and less computation time. The MATLAB simulation and experimental results are shown in order to verify the validity of the proposed current compensating algorithm.

An Error Correcting High Rate DC-Free Multimode Code Design for Optical Storage Systems (광기록 시스템을 위한 오류 정정 능력과 높은 부호율을 가지는 DC-free 다중모드 부호 설계)

  • Lee, June;Woo, Choong-Chae
    • Journal of the Institute of Convergence Signal Processing
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    • v.11 no.3
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    • pp.226-231
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    • 2010
  • This paper proposes a new coding technique for constructing error correcting high rate DC-free multimode code using a generator matrix generated from a sparse parity-check matrix. The scheme exploits high rate generator matrixes for producing distinct candidate codewords. The decoding complexity depends on whether the syndrome of the received codeword is zero or not. If the syndrome is zero, the decoding is simply performed by expurgating the redundant bits of the received codeword. Otherwise, the decoding is performed by a sum-product algorithm. The performance of the proposed scheme can achieve a reasonable DC-suppression and a low bit error rate.

Design of Zero-phase FIR Filters Through the Modeling and Analysis of A Frequency-domain Error Function (주파수영역 오차함수의 모델링과 분석을 통한 제로위상 FIR 필터 설계)

  • Jeon, Joon-Hyeon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.7C
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    • pp.451-458
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    • 2011
  • Maximally flat (MAXFLAT) FIR filter design provides the advantage of giving a closed-form solution, but there still remains a problem of exactly and efficiently choosing the order of flatness for the accurate design of filters. This paper provides, through the modeling and analysis of a frequency-domain error function in the closed-form solution, how to determine the order of flatness. A proposed method, based on the frequency-domain error function, is accomplished by computing a minimum distance between its peak frequency and specified cutoff frequency. It is also shown that the proposed scheme is computationally efficient and accurate than the empirical formula given by Herrmann.

Efficient Calculation for Decision Feedback Algorithms Based on Zero-Error Probability Criterion (영확률 성능기준에 근거한 결정궤환 알고리듬의 효율적인 계산)

  • Kim, Namyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.2
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    • pp.247-252
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    • 2015
  • Adaptive algorithms based on the criterion of zero-error probability (ZEP) have robustness to impulsive noise and their decision feedback (DF) versions are known to compensate effectively for severe multipath channel distortions. However the ZEP-DF algorithm computes several summation operations at each iteration time for each filter section and this plays an obstacle role in practical implementation. In this paper, the ZEP-DF with recursive gradient estimation (RGE) method is proposed and shown to reduce the computational burden of O(N) to a constant which is independent of the sample size N. Also the weight update of the initial state and the steady state is a continuous process without bringing about any propagation of gradient estimation error in DF structure.

Influence of Zero Reading on Predicting Crown Displacement of Tunnel (초기계측 시점이 터널 내공변위 예측에 미치는 영향분석)

  • Kim, Kwang-Yeom;Kim, Ho-Geun;Seo, Youg-Seok
    • Tunnel and Underground Space
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    • v.22 no.3
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    • pp.214-220
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    • 2012
  • Deformation behaviour of rock mass around an opening measured during tunnel excavation is very important in order to assess the stability of the tunnel. Unfortunately displacement measured only after the installation of displacement measuring device can be acquired, which results in inevitably excluding the pre-displacement occurred and accumulated before the displacement measuring devices are installed. So it is very important to consider the pre-displacement based on the elapsed time before zero reading after deformation behaviour started. In this study, the accuracy of total estimated displacement depending on the distance between face and measurement position is calculated by statistical non-linear fitting on measurable displacement data. Besides, the influence of the unavoidable measurement error is considered by using Monte-Carlo simulation. As a result, the faster the initial reading started and the smaller the measurement error is, the higher the accuracy of estimating total displacement is obtained.

Analysis and Prediction of Prosodic Phrage Boundary (운율구 경계현상 분석 및 텍스트에서의 운율구 추출)

  • Kim, Sang-Hun;Seong, Cheol-Jae;Lee, Jung-Chul
    • The Journal of the Acoustical Society of Korea
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    • v.16 no.1
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    • pp.24-32
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    • 1997
  • This study aims to describe, at one aspect, the relativity between syntactic structure and prosodic phrasing, and at the other, to establish a suitable phrasing pattern to produce more natural synthetic speech. To get meaningful results, all the word boundaries in the prosodic database were statistically analyzed, and assigned by the proper boundary type. The resulting 10 types of prosodic boundaries were classified into 3 types according to the strength of the breaks, which are zero, minor, and major break respectively. We have found out that the durational information was a main cue to determine the major prosodic boundary. Using the bigram and trigram of syntactic information, we predicted major and minor classification of boundary types. With brigram model, we obtained the correct major break prediction rates of 4.60%, 38.2%, the insertion error rates of 22.8%, 8.4% on each Test-I and Test-II text database respectively. With trigram mode, we also obtained the correct major break prediction rates of 58.3%, 42.8%, the insertion error rates of 30.8%, 42.8%, the insertion error rates of 30.8%, 11.8% on Test-I and Test-II text database respectively.

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