• Communications for Statistical Applications and Methods
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• 제29권6호
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• pp.655-664
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• 2022

On the motivation by an integrative study of multi-omics data, we are interested in estimating the structure of the sparse cross correlation matrix of two high-dimensional random vectors. We rewrite the problem as a multiple testing problem and propose a new method to estimate the sparse structure of the cross correlation matrix. To do so, we test the correlation coefficients simultaneously and threshold the correlation coefficients by controlling FRD at a predetermined level α. Further, we apply the proposed method and an alternative adaptive thresholding procedure by Cai and Liu (2016) to the integrative analysis of the protein expression data (X) and the mRNA expression data (Y) in TCGA breast cancer cohort. By varying the FDR level α, we show that the new procedure is consistently more efficient in estimating the sparse structure of cross correlation matrix than the alternative one.

• 한국음향학회지
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• 제9권2호
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• pp.42-52
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• 1990

음향전파 측정에 상호상관법(직접법과 M계열 변조상관법)을 이용하므로서 임펄스 입력에 의한 경우와 같은 결과를 얻을 수 있다는 것과, 또 상호상관법의 특징인 외란노이즈의 영향을 줄일 수 있었던 것 등을 건축음향분야에서 측정계를 대상으로 하여 이론적으로 정리하였다. 또 이들 계측법을 응용하여 흡음재료의 사입사 흡음특성의 측정, 실의 단독 단음응답 및 잔향감쇄 과정의 측정, 음압레벨 분포, 차음성능 등을 측정하고 여러 건축음향측정에서 이들 방법이 유효하다는 것을 실험적으로 확인하였다.

• Journal of Information Technology Applications and Management
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• 제24권1호
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• pp.157-167
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• 2017

This paper proposes a simple sound source localization (SSL) method based on signal energies comparison and partial cross correlation for TDOA computation. Many sound source localization methods include multiple TDOA computations in order to eliminate front-back confusion. Multiple TDOA computations however increase the methods' computation times which need to be as minimal as possible for real-time applications. Our aim in this paper is to achieve the same results of localization using fewer computations. Using three microphones, we first compare signal energies to predict which quadrant the sound source is in, and then we use partial cross correlation to estimate the TDOA value before computing the azimuth value. Also, we apply a threshold value to reinforce our prediction method. Our experimental results show that the proposed method has less computation time; spending approximately 30% less time than previous three microphone methods.

• Smart Structures and Systems
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• 제16권1호
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• pp.213-222
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• 2015

Early detection and precise location of leakage is of great importance for life-cycle maintenance and management of municipal pipeline system. In the past few years, acoustic emission (AE) techniques have demonstrated to be an excellent tool for on-line leakage detection. Regarding the multi-mode and frequency dispersion characteristics of AE signals propagating along a pipeline, the direct cross-correlation technique that assumes the constant AE propagation velocity does not perform well in practice for acoustic leak location. This paper presents an improved cross-correlation method based on wavelet transform, with due consideration of the frequency dispersion characteristics of AE wave and the contribution of different mode. Laboratory experiments conducted to simulate pipeline gas leakage and investigate the frequency spectrum signatures of AE leak signals. By comparing with the other methods for leak location identification, the feasibility and superiority of the proposed method are verified.

• Journal of Information Technology Applications and Management
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• 제22권3호
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• pp.105-114
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• 2015

This paper presents a fast Time Difference of Arrival (TDOA) estimation for sound source localization. TDOA is the time difference between the arrival times of a signal at two sensors. We propose a partial cross correlation method to increase the speed of TDOA estimation for sound source localization. We do this by predicting which part of the cross correlation function contains the required TDOA value with the help of the signal energies, and then we compute the cross correlation function in that direction only. Experiments show approximately 50% reduction in the cross correlation computation time thereby increasing the speed of TDOA computation. This makes it very relevant for real world surveillance.

• 한국정보통신학회논문지
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• 제16권8호
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• pp.1686-1692
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• 2012

확산수열(spreading sequence)은 다중 반송파 대역확산(multi-carrier spectrum) 통신시스템과 CDMA와 같은 무선통신에서 중요한 역할을 한다. 이러한 통신 시스템에서 낮은 상호상관관계를 갖는 확산수열은 다중접속 충돌을 최소화하고, 시스템의 보안수준을 가능한 높일 수 있다. 수열을 설계하는 데 있어 상호상관관계를 분석한는 것을 반드시 필요한 절차이다. 상호상관관계를 분석하기 위해서는 많은 계산 시간이 요구된다. 본 논문에서는 비선형 이진수열의 상호상관관계를 실제적으로 계산하는 과정에서 부분체를 이용하여 효과적으로 구하는 방법을 제안한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.100-105
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• 1998

Image processing was used to recognize parts at various disposition. Non-transpatent tachometer panel for automobile and semi-transparent panel have been used as test specimen. Laplacian filter and various threshold values have been applied for preprocessing and edge following algorithm has been applied. Series of length data between edges have been generated from each image and compared using cross correlation coefficient. The result using cross correlation coefficient. The result using both edge following and cross correlation coefficient was proven to be the best fit for the proposed parts.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.781-784
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• 1994

Detecting partial discharge(PD) and locating its source are one of many diagnosis methods. Location the PD source is very important to reduce the time and cost of repairing power transformers. And to locate the PD source, the cross-correlation method is a well known one. But there many spurious peaks in cross-correlation, and occasionally, some peaks could be bigger than the true one. In order to analysis these spurious peaks and to reduce them, we have done many experiments and simulations. As the results we could reduce the spurious peaks, and get well defined cross-correlation from which it is easy to locate the PD source accurately.

• Journal of Power Electronics
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• 제10권6호
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• pp.762-768
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• 2010

This paper describes the development of a new islanding detection method for inverter-based distributed generation systems, which uses a signal cross-correlation scheme between the injected reactive current and the power frequency deviation. The proposed method injects 1% of the reactive current to the rated current which brings about a negligible degradation of the power quality. It discriminates the islanding state, when the calculated cross-correlation index is larger than 0.5. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software and experimental research with a hardware prototype. The proposed method can detect the islanding state without degrading the power quality at the point of common connection. Further study is required to overcome the cancellation of the injected reactive current from multiple distributed generation units interconnected with the utility grid.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.84-89
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• 2003

Water leak is one of topics with great concern in Korea and many other countries, because of decreasing water supplies and the deterioration of old pipeworks. Correlation techniques have been widely used in leak detection of water pipes, which allow to locate a leak point based on the correlation of leak noise at two sites along water pipes. In this study, both the cross-correlation method and the conventional arrival time difference method are applied in order to analyze and to locate a leak point of a water pipe. In experiment, a 150 m of whole length waterwork pipeline system was constructed in a ground, and several types of leak noise were installed on the pipeline in order to control leak condition. Both the cross-correlation technique and the arrival time difference method showed favorable results at leak detection with the experimental pipeline system.