• 제목/요약/키워드: auto-and cross-correlation

검색결과 79건 처리시간 0.023초

크기가 다른 단면을 가진 평행한 두 채널을 연결하는 협소유로의 맥동유동에 관한 수치해석 (Numerical Investigation of the Flow Pulsation in the Gap connecting with Two Parallel Channels with Different Cross-section Areas)

  • 서정식;홍성호;신종근;최영돈
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2810-2815
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    • 2008
  • Flow pulsation in the gap connecting with two parallel channels is investigated by RANS and URANS approaches. The two parallel channels are connected by a small channel called for a gap. The parallel channels are designed to have different cross section area with its ratio of 0.5. Computations are conducted using a CFX 11.0 code. The bulk Reynolds number is 60,000. Predicted results are compared with the previous experimental result. Mean velocity profile at the center of gap region are compared with experiments for its validation. Spectral analysis on the lateral velocity in the center of the gap is presented. Auto and cross correlation for the axial-flow velocity pattern are presented. The unsteady structure of the flow pulsation was visualized in the region of the gap in the parallel channel.

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단위 충격 응답함수를 이용한 원형관 시스템의 주출감지 연구 (Leak Detection of Circular Piping Systems by Using Unit Impulse Response Function Analysis)

  • 전오성;윤병옥;김창호
    • 소음진동
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    • 제4권3호
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    • pp.337-343
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    • 1994
  • A method of the leak detection from the pipe system by using accelerometer is proposed. The signal detected from accelerometer is proved experimentally to be a dispersive wave. Based on the experiments, a method using the narrow band pass filter and the unit impulse response function is analyzed. The method uses the characteristics of the unit impulse response function, that the function is available evenin the narrow band signal because, unlike the cross correlation, it is normalized by the auto spectrum. The accelerometer is quite easier to use than the hydrophone in adapting to the pipe system.

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정보인자분석(情報因子分析)을 위한 통합예측(統合豫測)모델의 설계(設計) 및 해석(解析) (Design and Elucidation of Integrated Forecasting Model for Information Factor Analysis)

  • 김홍재;이태희
    • 품질경영학회지
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    • 제21권1호
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    • pp.181-189
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    • 1993
  • Over the past two decades, forecasting has gained widespread acceptance as an integral part of business planning and decision making. Accurate forecasting is a prerequisite to successful planning. Accordingly, recent advances in forecasting techniques are of exceptional value to corporate planners. But most of forecasting mothods are reveal its limit and problem for precision and reliability duing to each relationship for raw data and possibility of explanation for each variable. Therefore, to construct the Integrated Forecasting Model(IFM) for Information Factor Analysis, it shoud be considered that whether law data has time lag and variables are explained. For this. following several method can be used : Least Square Method, Markov Process, Fibonacci series, Auto-Correlation, Cross-Correlation, Serial Correlation and Random Walk Theory. Thus, the unified property of these several functions scales the safety and growth of the system which may be varied time-to-time.

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회전불변 패턴인식을 위한 WCHF-FSJTC (Wavelet circular harmonic function frequency selective joint transform correlator for rotation invariant pattern recognition)

  • 방준학;이하운;노덕수;김수중
    • 전자공학회논문지S
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    • 제34S권2호
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    • pp.94-103
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    • 1997
  • The WCHF-FSJTC (wavelet circular harmonic function frequency selective joint transform correlator) using th wavelet transformed CHF as the reference image in FSJTC is proposed for rotation invariant pattern recognition. Since the wavelet transform has the property of feature extraction, the proposed system can have the better DC (discrimination cpability) and the higher SNR(signal to noise ratio) compared with the conventional CHF-CJTC(circular harmonic function conventional joint transform correlator). And since the structure of the proposed system is FSJTC which can eliminate auto-correlation and cross-correlation between input images, it can eliminate false alarm caused by the overlapping among correlation peaks. The used wavelet functio is the morlet function, which is proper for the reference image used in this paper. the optimal dialation parameter and oscillation frequency of the wavelet function are also achieved with varying the parameters of the wavelet function. The computer simulation shows that the proposed system has the best performance when the dilation parameter is 0.8 and the oscillation frequency is 0.48.

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변동경향성 제거 전후의 수리지질학적 시계열분석 결과 비교 (Comparison of Hydrogeological Time Series Analysis Results Before and After Detrending)

  • 임홍균;최현미;이진용
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제16권2호
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    • pp.30-40
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    • 2011
  • In this study, we compared the analysis results before and after the detrending for the data. According to the comparison results, correlation functions were not much changed while autocorrelation and spectral density functions were largely varied. Especially, time series data with a long-term variation trend showed a distinctive difference. This study demonstrated a usefulness of the detrending for a further analysis.

Application of AutoFom III equipment for prediction of primal and commercial cut weight of Korean pig carcasses

  • Choi, Jung Seok;Kwon, Ki Mun;Lee, Young Kyu;Joeng, Jang Uk;Lee, Kyung Ok;Jin, Sang Keun;Choi, Yang Il;Lee, Jae Joon
    • Asian-Australasian Journal of Animal Sciences
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    • 제31권10호
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    • pp.1670-1676
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    • 2018
  • Objective: This study was conducted to enable on-line prediction of primal and commercial cut weights in Korean slaughter pigs by AutoFom III, which non-invasively scans pig carcasses early after slaughter using ultrasonic sensors. Methods: A total of 162 Landrace, Yorkshire, and Duroc (LYD) pigs and 154 LYD pigs representing the yearly Korean slaughter distribution were included in the calibration and validation dataset, respectively. Partial least squares (PLS) models were developed for prediction of the weight of deboned shoulder blade, shoulder picnic, belly, loin, and ham. In addition, AutoFom III's ability to predict the weight of the commercial cuts of spare rib, jowl, false lean, back rib, diaphragm, and tenderloin was investigated. Each cut was manually prepared by local butchers and then recorded. Results: The cross-validated prediction accuracy ($R^2cv$) of the calibration models for deboned shoulder blade, shoulder picnic, loin, belly, and ham ranged from 0.77 to 0.86. The $R^2cv$ for tenderloin, spare rib, diaphragm, false lean, jowl, and back rib ranged from 0.34 to 0.62. Because the $R^2cv$ of the latter commercial cuts were less than 0.65, AutoFom III was less accurate for the prediction of those cuts. The root mean squares error of cross validation calibration (RMSECV) model was comparable to the root mean squares error of prediction (RMSEP), although the RMSECV was numerically higher than RMSEP for the deboned shoulder blade and belly. Conclusion: AutoFom III predicts the weight of deboned shoulder blade, shoulder picnic, loin, belly, and ham with high accuracy, and is a suitable process analytical tool for sorting pork primals in Korea. However, AutoFom III's prediction of smaller commercial Korean cuts is less accurate, which may be attributed to the lack of anatomical reference points and the lack of a good correlation between the scanned area of the carcass and those traits.

모호함수를 이용한 레이더 신호 생성기법 (Radar Signal Generation Technique using Ambiguity Function)

  • 홍동희;박성철;이성용;김정렬;박진규
    • 한국군사과학기술학회지
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    • 제6권4호
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    • pp.80-88
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    • 2003
  • Radar signal simulation is increasingly gaining in importance according as modem radar systems are more complex. Although computer performance has been advanced, it is difficult to implement the real-time simulation because the detailed model for the radar is necessary to get the desired accuracy. In order to achieve real time operation, we propose radar signal generation technique using ambiguity function, Instead of wellknown correlation method. The ambiguity function is the mathematical modeling of the signal processing procedure which is a simulation section to require the most computations.

Pseudo-Correlation-Function Based Unambiguous Tracking Technique for CBOC (6,1,1/11) Signals

  • Jeong, Gil-Seop;Kong, Seung-Hyun
    • Journal of Positioning, Navigation, and Timing
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    • 제4권3호
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    • pp.107-114
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    • 2015
  • Binary Offset Carrier (BOC) signal planned for future Global Navigation Satellite System (GNSS) provided better positioning accuracy and smaller multipath error than GPS C/A signal. However, due to the multiple side peaks in the auto-correlation function (ACF) of the BOC modulated signals, a receiver may false lock onto one of the side peaks in the tracking mode. This false lock would then result in a fatal tracking error. In this paper, we propose an unambiguous tracking method for composite BOC (CBOC) signals to mitigate this problem. It aims to reduce the side peaks of the ACF of CBOC modulated signals. It is based on the combination of traditional CBOC correlation function (CF) and reference CF of unmodulated pseudo- random noise code (PRN code). First, we present that cross-correlation function (CCF) with unmodulated PRN code is close to the secondary peaks of the traditional CBOC. Then, we obtain an unambiguous correlation function by subtracting traditional CBOC ACF from these CFs. Finally, the tracking performance for the CBOC signals is examined, and it is shown that the proposed method has better performance than the traditional unambiguous tracking method in additive white Gaussian noise (AWGN) channel.

연안해역 기온과 수온의 상관관계 및 이력현상 분석 (Correlation and Hysteresis Analysis between Air and Water Temperatures in the Coastal Zone - Masan Bay)

  • 조홍연;이길하;조경준;김준성
    • 한국해안해양공학회지
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    • 제19권3호
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    • pp.213-221
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    • 2007
  • 전지구적으로 지구 온난화 문제가 대두되고 있는 현 상황에서, 기온변화에 수반되는 수온변화 반응을 파악하기 위하여 해양수산부에서 제공하는 마산만 연안해역의 기온 및 수온 관측자료를 이용하여 기온과 수온의 관계를 분석하였다. 수온과 기온의 무차원 자기상관함수와 교차상관함수 변화를 분석한 결과, 지체시간 10일 이내에서는 상관계수가 0.9 이상으로 매우 크게 나타났으며, 지점별로 수온의 상관계수보다 기온의 상관계수가 크게 나타나는 것으로 파악되었다. 마산만 기온 및 수온자료를 수온상승기, 수온하강기로 구분하여 분석한 결과, 수온상승기에는 MA1 지점, MA2 지점의 기울기가 각각 0.829, 0.774로 나타났으며, 수온하강기에는 MA1 지점, MA2 지점의 기울기가 각각 1.385, 1.444로 기온상승기에 비하여 기온하강기의 기울기가 약 1.75배 정도 크게 나타나고 있으며, 명확한 이력현상으로 파악되었다. 따라서, 마산만 연안해역의 기온-수온 상관관계를 보다 정확하게 결정하기 위해서는 기온-수온의 계절적인 이력현상을 포함하여야 하며, 이 경우 기온을 이용한 수온 추정결과의 정확도가 향상되는 것으로 파악되었다.

하천오염인자의 통계적 특성 (Statistical Characteristics of Pollutants in Sterm Flow)

  • 황임구;윤태훈
    • 물과 미래
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    • 제14권4호
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    • pp.19-26
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    • 1981
  • 자연하천에서의 수질은 유량의 변화에 많은 영향을 받을 것으로 기대되는 바, 유량과 각 수질인자의 통계적 특성 및 유량변화와 수질인자간의 상관관계를 조사하기 위하여 자기 및 상호상관함수 power spectrum, coherence 함수 및 Markov 모형을 적용하였다. 일부 자료만이 입수 가능한 한강 하류부 인도교 지점에서의 유량, 용존산소, 전기전도도는 명백한 1년 주기와 6, 4, 3개월의 약한 주기를 가지며, 유량과 용존산소, 유량과 전도도 사이의 상관은 약하게 나타났고 상호상관함수에서 첨두가 지체 1일에서 발생하여 미약하지만 유량의 변화에 의한 영향이 1일 정도 차이로 수질인자에게 미치는 것으로 해석된다. 계열 발생 및 예측수단인 선형회귀모형의 검토에서 유량은 1차 및 2차 Markov 모형과, 용존산소와 전도도는 1차 Markov 모형과 흡사하게 나타났다.

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