• Title/Summary/Keyword: Recursive RMS method

Search Result 5, Processing Time 0.025 seconds

Equivalent 10-Hz Flicker Index Calculation Using Half-cycle Sliding Window and Recursive RMS Method (반주기 슬라이딩 윈도우와 재귀적 실효치 계산을 이용한 국내 플리커 평가지수 산출기법)

  • Cho, Soo-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.60 no.11
    • /
    • pp.2017-2020
    • /
    • 2011
  • Flicker, which is also known as voltage fluctuation, is an electromagnetic phenomenon generated by large scale nonlinear loads, such as arc furnaces and welding machines. Since a severe and continuous flicker can cause to some damages to electrically sensitive loads as well as human's visual irritations, it needs to be appropriately managed by being accurately measured, quantified and assessed. In Korea, an equivalent 10-Hz flicker index, shortly ${\Delta}V10$, is used to determine the permission limit of flicker. This paper presents an efficient calculation of the flicker index by using a half-cycle sliding window and a recursive method, showing a concrete calculating procedure of ${\Delta}V10$ from the viewpoint of signal processing.

NEW ADAPTIVE METHOD FOR VOLTAGE SAG AND SWELL DETECTION

  • Mohamed, Mansour A.
    • Journal of the Korea Convergence Society
    • /
    • v.4 no.1
    • /
    • pp.33-41
    • /
    • 2013
  • This paper presents an adaptive recursive least squares algorithm (ARLS) for detecting voltage sag and voltage swell events in power systems. Different methods have been developed to detect voltage sag and voltage swell. Some of them use window techniques, which are too slow when voltage sag or swell mitigation is required. Others depend on the extraction of a single non-stationary sinusoidal signal out of a given multi-components input signal, and therefore they don't consider the harmonic components in calculating the voltage root mean square value (rms). The method, proposed in this paper, is capable of estimating the voltage rms taking into account all harmonic components. The method is tested by applying it to different, simulated signals using ATP program, and compared with voltage sag detection algorithms.

An Improved Fractal Color Image Decoding Based on Data Dependence and Vector Distortion Measure (데이터 의존성과 벡터왜곡척도를 이용한 개선된 프랙탈 칼라영상 복호화)

  • 서호찬;정태일;류권열;권기룡;문광석
    • Journal of Korea Multimedia Society
    • /
    • v.2 no.3
    • /
    • pp.289-296
    • /
    • 1999
  • In this paper, an improved fractal color image decoding method using the data dependence parts and the vector distortion measure is proposed. The vector distortion measure exploits the correlation between different color components. The pixel in RGB color space can be considered as a 30dimensional vector with elements of RGB components. The root mean square error(rms) in RGB color for similarity measure of two blocks R and R' was used. We assume that various parameter necessary in image decoding are stored in the transform table. If the parameter is referenced in decoding image, then decoding is performed by the recursive decoding method. If the parameter is not referenced in decoding image, then the parameters recognize as the data dependence parts and store its in the memory. Non-referenced parts can be decoded only one time, because its domain informations exist in the decoded parts by the recursive decoding method. Non-referenced parts are defined the data dependence parts. Image decoding method using data dependence classifies referenced parts and non-referenced parts using information of transform table. And the proposed method can be decoded only one time for R region decoding speed than Zhang & Po's method, since it is decreased the computational numbers by execution iterated contractive transformations for the referenced range only.

  • PDF

Identification of guideway errors in the end milling machine using geometric adaptive control algorithm (기하학적 적응제어에 의한 엔드밀링머시인의 안내면 오차 규명)

  • 정성종;이종원
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.12 no.1
    • /
    • pp.163-172
    • /
    • 1988
  • An off-line Geometric Adaptive Control Scheme is applied to the milling machine to identify its guideway errors. In the milling process, the workpiece fixed on the bed travels along the guideway while the tool and spindle system is fixed onto the machine. The scheme is based on the exponential smoothing of post-process measurements of relative machining errors due to the tool, workpiece and bed deflections. The guideway error identification system consists of a gap sensor, a, not necessarily accurate, straightedge, and the numerical control unit. Without a priori knowledge of the variations of the cutting parameters, the time-varying parameters are also estimated by an exponentially weighted recursive least squares method. Experimental results show that the guideway error is well identified within the range of RMS values of geometric error changes between machining passes disregarding the machining conditions.

A Robust Digital Pre-Distortion Technique in Saturation Region for Non-linear Power Amplifier (비선형 전력 증폭기의 포화영역에서 강인한 디지털 전치왜곡 기법)

  • Hong, Soon-Il;Jeong, Eui-Rim
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2015.05a
    • /
    • pp.681-684
    • /
    • 2015
  • Power amplifier is an essential component for transmitting signals to a remote receiver in wireless communication systems. Power amplifier is a non-linear device in general, and the nonlinear distortion becomes severer as the output power increases. The nonlinearity results in spectral regrowth, which leads to adjacent channel interference, and decreases the transmit signal quality. To linearize power amplifiers, many techniques have been developed so far. Among the techniques, digital pre-distortion is known as the most cost and performance effective technique. However, the linearization performance falls down abruptly when the power amplifier operates in its saturation region. This is because of the severe nonlinearity. To relieve this problem, this paper proposes a new adaptive predistortion technique. The proposed technique controls the adaptive algorithm based on the power amplifier input level. Specifically, for small signals, the adaptive predistortion algorithm works normally. On the contrary, for large signals, the adaptive algorithm stops until small signals occur again. By doing this, wrong coefficient update by severe nonlinearity can be avoided. Computer simulation results show that the proposed method can improve the linearization performance compared with the conventional digital predistortion algorithms.

  • PDF