• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.1029-1039
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• 1992

This paper presents the filtering method which is processed on the frequency domain among Hangul character recognition methods. It is processed the Hangul character parrern with spatial positioning modulation and mapped the Hangul character element which have spatial position variant feature onto frequency domain, at this time, normalized spatial position and so normalized the character size in frequency domain. And it is grouped the Hangul character element according to the generating position and set the standard pattern, and used each standard character element pattern with character element filter and filtering the character pattern of Hangul character, it is derived the normalized cross correlation function and the coherence function led to the filtering results, and calculated classification threshold.

• Communications for Statistical Applications and Methods
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• v.17 no.5
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• pp.697-712
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• 2010

This paper is concerned with the statistical analysis and development of stochastic models for the demand for life insurance policy loans. For these, firstly the characteristics of the regression trend, periodicity and dependence of the monthly demand for life insurance policy loans are investigated by a statistical analysis of the monthly demand data for the years 1999 through 2008. Secondly, the causal relationships between the demand for life insurance policy loans and the economic variables including unemployment rate and inflation rate for the period are investigated. The results show that inflation rate is main factor influencing policy loan demands. The overall evidence, however, failed to establish unidirectional causality relationships between the demand series and the other variables under study. Finally, based on these, univariate time series model and transfer function model where the demand series is related to one input series are derived, respectively, for the prediction of the demand for life insurance policy loans. A statistical procedure for using the model to predict the demand for life insurance policy loans is also proposed.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.1
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• pp.44-52
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• 2014

Leakage is an important factor to be considered for the management of underground water supply pipelines in a smart water grid system, especially if the pipelines are aged and buried under the pavement or various structures of a highly populated city. Because the exact detection of the location of such leaks in pipelines is essential for their efficient operation, a new methodology for leak location detection based on frequency band variation, windowing filters, and probability is proposed in this paper. Because the exact detection of the leak location depends on the precision of estimation of time delay between sensor signals due to leak noise, some window functions that offer weightings at significant frequencies are applied for calculating the improved cross-correlation function. Experimental results obtained by applying this methodology to an actual buried water supply pipeline, ~ 253.9 m long and made of cast iron, revealed that the approach of frequency band variation with those windows and probability offers better performance for leak location detection.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.123-129
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• 2000

This paper addresses a new double detection algorithm which is based on the fuzzy control in the adaptive echo canceller of communication system. In this method, the two input of the fuzzy inference for detecting double talk condition are used. The one is the cross-correlation coefficient between the error signal and the primary signal which is the summed signal of the real echo signal and the near-end signal. The other is the cross-correlation coefficient between the estimation error signal and the primary signal. The fuzzy controller made a fuzzification for two inputs by the membership functions of trapezoid and them became the composition using inference rules. The composed result is defuzzificated by the center gravity method. The output is compared with two threshold values to detect double talk and echo path variation effectively. It is confirmed by computer simulation that this fuzzy double talk detector is able to track echo path variation accurately.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9A
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• pp.909-916
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• 2008

In this paper, we propose and analyze M-ary pulse order time hopping multiple access ultra wideband (PO-THMA UWB) system using modified Hermite polynomial (MHP). The MHP pulses have a mutually orthogonal property between different ordered pulses and that property makes simultaneous transmission at the same time slot regardless of collision in the THMA-UWB system. Therefore, we derive the cross-correlation furlction of MHP pulses and analyze the BER of the proposed system and show that the BER performance and the transmission capacity are improved dramatically when compared with those of conventional THMA-UWB system.

• Journal of the Korean Data and Information Science Society
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• v.20 no.4
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• pp.655-660
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• 2009

As the global economic crisis, the Korean foreign exchange market appears unstable with large fluctuations in exchange rate. Inevitably, there is growing attention on price variables such as exchange rate and interest rates and also on corelation between the factors. This is an empirical study on the causality of fluctuation between exchange rate and interest rate in the Korean market under global economic crisis. The fluctuations in won/dollar exchange rate and call rate are described and followed by analysis of lead-lag relationship between the two variables using Cross-correlation function and Granger causality test.

• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.118-128
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• 1989

This experiment was conducted to study the relation between the equilibrium moisture contents and the hygroscopic components in the various tobacco matters such as NC-82, Br-21, R.T.S., and puffed stem. The order of the high equilibrium moisture contents was the puffed stem, R.T.S., NC-82, and Br-21. The H-1 grades of NC-82 and Br-21 contained high contents of total sugar had higher equilibrium moisture contents than others. The moisture contents in NC-82 and Br-21 were increased at higher temperature, $30^{\circ}C$ than $20^{\circ}C$. The grades with high amounts of water extracts and total sugar affected to increase the equilibrium moisture contents in NC-82 and Br-21. In conclusion, the equilibrium contents were related to the structure of tobacco matter, the grades, the temperature, and the amount of some chemical components such as water extracts and total sugar of the leaf tobacco.

• Explosives and Blasting
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• v.16 no.2
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• pp.34-46
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• 1998

We developed a method to control vibration from some blasting points. This method uses a correlation of vibration waves to decide the most effective delay time to control vibration by interfering vibration waves with each other. We applied this method to the small blasting using mortar blocks and examined the effect on controlling vibration. As the result of the examinations, the maximum vibration velocity by this method caused by five detonators blasting in row of five holes became smaller than that by a detonator blasting in the nearest hole from the measuring point. And the velocity was about one fifth of that of maximum condition in which vibration waves caused by the five detonators arrivved at the same time to the measuring point.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1870-1871
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• 2011

본 논문에서는 전력케이블에서의 시간-주파수 영역 반사파 계측법을 기반으로 한 기준신호를 설계한다. 사용된 기준신호는 시간과 주파수 영역에서 동시에 분석할 수 있는 가우시안 포락선을 가지는 첩 신호이다. 10m 전력케이블의 특성에 적합하게 설계된 기준신호를 케이블에 직접 인가하여 반사파를 측정하고 정규화된 시간-주파수 영역 상호상관함수로 비교 분석하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2000.11b
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• pp.37-41
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• 2000

본 연구는 디지털 오디오 데이터의 전송 및 배포과정에서 필요한 워터마크기술에 관한 것이 다. 삽입 방법은 일종의 확산 스펙트럼 방식으로 특정 Key 에 의해 생성된 의사난수신호를 인간의 가청주파수모델과 오디오 신호의 특성에 따라 조작 한 후 삽입하게 된다. 이러한 주파수 조작은 데이터 은닉의 inaudibility 와 audio compression에의 견고성을 위하여 필요 한 사항이다. 워터마크 추출과정에서는 일정한 길이의 오디오 신호 앙상블 평균을 구하고, 이 신호와 워터마크와의 상호 상관함수를 구하여 워터마크의 삽입 유무를 판단하게 된다. 알고리즘의 테스트 결과 본 기술은 오디오 압축 및 오디오 조작에 강인한 것으로 나타났다.