• 대한화학회지
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• 제55권1호
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• pp.7-13
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• 2011

전자구조의 계산에서 교환과 상관 효과에 대한 기술을 개선하기 위해서는 교환-상관범함수에 대한 개념을 명확히 하는 것이 바람직하다. 이 목적을 성취하기 위해서는 많은 그룹의 물질에 대하여 다른 이론 방법을 적용할 필요가 있다. 본 연구에서는 탄소나노튜브의 고리와 바구니 내원자들의 밀도전하를 연구하기 위하여 혼성 밀도함수 이론(DFT) 계산을 수행하였다. 핵-핵 에너지, 전자-핵 에너지와 운동에너지에 대한 교환 및 상호작용을 관찰하였으며, B3P86, B3PW91, B1B96, BLYP와 B3LYP 수준에서 계산하였다.

• International Journal of Ocean System Engineering
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• 제2권1호
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• pp.16-23
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• 2012

In this paper we discussed a new methodology for Urdu Character Recognition system using Dempster-Shafer theory which can powerfully estimate the similarity ratings between a recognized character and sampling characters in the character database. Recognition of character is done by five probability calculation methods such as (similarity, hamming, linear correlation, cross-correlation, nearest neighbor) with Dempster-Shafer theory of belief functions. The main objective of this paper is to Recognition of Urdu letters and numerals through five similarity and dissimilarity algorithms to find the similarity between the given image and the standard template in the character recognition system. In this paper we develop a method to combine the results of the different distance measurement methods using the Dempster-Shafer theory. This idea enables us to obtain a single precision result. It was observed that the combination of these results ultimately enhanced the success rate.

• 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.

• Communications for Statistical Applications and Methods
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• 제14권2호
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• pp.301-307
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• 2007

A effective teaching method on correlation coefficient for elementary level statistics course is discussed in this article. The well known inequalities, such as Theorem 368 of Hardy et al. (1952), are used for the interpretation of concept of covariance. An Excel example is provided for the illustration of concept of correlation coefficient.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(1)
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• pp.333-338
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• 1995

This paper discusses the methods for building up the empirical CHF correlation, Direct Substitution Method (DSM) and Heat Balance Method (HBM). It also includes consideration on the CHF manin, which ran be expressed differently depending on the correlation types in use. Some findings an presented with exemplary calculation.

• ETRI Journal
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• 제43권1호
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• pp.31-39
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• 2021

One of the major challenges in wireless body area networks (WBANs) is sensor fault detection. This paper reports a method for the precise identification of faulty sensors, which should help users identify true medical conditions and reduce the rate of false alarms, thereby improving the quality of services offered by WBANs. The proposed sensor fault detection (SFD) algorithm is based on Pearson correlation coefficients and simple statistical methods. The proposed method identifies strongly correlated parameters using Pearson correlation coefficients, and the proposed SFD algorithm detects faulty sensors. We validated the proposed SFD algorithm using two datasets from the Multiparameter Intelligent Monitoring in Intensive Care database and compared the results to those of existing methods. The time complexity of the proposed algorithm was also compared to that of existing methods. The proposed algorithm achieved high detection rates and low false alarm rates with accuracies of 97.23% and 93.99% for Dataset 1 and Dataset 2, respectively.

• International Journal of Quality Innovation
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• 제4권2호
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• pp.16-31
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• 2003

A reducing variation of quality characteristics is a typical example of quality improvement. In such a case, we treat the quality characteristic, as a response variable and need to find active factors affecting the response from many candidate factors since reducing the variation of the response will be achieved by reducing variation of the active factors. In this paper, we first derive a method of selecting an active factor by linear regression. It is well known that correlation between factors deteriorates the precision of estimators. We, therefore, examine robustness of the selecting method against the correlation in the data set and derive an evaluation method of the deterioration brought by the correlation. Furthermore, some examples of selecting and evaluation methods are shown to demonstrate practical usage of the methods.

• 대한물리치료과학회지
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• 제18권2호
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• pp.63-71
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• 2011

Purpose: This study is designed to examine the effect of self-efficacy on stress-coping methods of health related and non-health related department college students. Method: A questionnaire survey was conducted on 533 students (268 health department and 265 non-health department) of health department and non-health department students at 1 university and 2 university in Gyeonggi-do, jeollabuk-do and jeollanam-do. Results: The results were statistically analyzed using SPSS 12.0, which made no statistically-significant difference among health and non-health students. The study on the effect of self-efficacy on stress-coping methods has revealed that both health and non-health department students showed statistically-significant positive correlation between self-efficacy and emotion-centered coping methods. Also, Social efficacy had negative correlation with social-supported coping methods. While non-health department students had statistically-significant positive correlation between self-efficacy and wishful coping. Conclusion: Accordingly, it has been revealed that self-efficacy is effective in stress-coping methods.

• 대한전자공학회논문지TC
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• 제45권7호
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• pp.32-37
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• 2008

DVB-S2 (Digital Video Broadcasting - Satellite Version 2)와 같은 위성 통신 시스템은 낮은 신호 대 잡음 비 (SNR; Signal-to-Noise Ratio) 및 큰 주파수 오차에서의 동작이 요구되므로 인해 초기 프레임 동기 과정에서 강건한 프레임 동기 획득을 위한 상관 방식이 필요하다. 초기 프레임 동기 획득을 위해서는 기존의 다양한 상관 방식이 존재하며 채널 환경에 따라 이들 상관 방식은 각각 다른 특성 및 성능을 갖는다. 본 논문에서는 낮은 신호 대 잡음 비 영역 및 큰 주파수 오차 존재 하에서도 우수한 성능을 보이는 상관기 구조를 제시하고 그 성능을 분석 및 검증한다. 제안하는 상관 방식은 동기 수열 내에서 확장된 동기 심볼 거리에 대한 차등 상관의 크기 합과 벡터 합을 각각 이용하며, 계산된 상관값과 수신신호의 Euclidean 거리를 활용하므로써 수신 신호와 동기 수열의 상관도를 극대화하는 효과를 갖는다. 크기 합 상관 방식의 경우 4 dB 이하의 신호 대잡음 비에서 주파수 오차의 존재 유무에 관계없이 최대 우도 (ML; Maximum likelihood) 방식의 근사화를 통해 유도된 방식을 포함한 기존의 알려진 모든 상관 방식보다 향상된 오율을 가지며, 벡터 합 상관 방식은 주파수 오차 감소함에 따라 크기 합 상관 방식보다도 더욱 우수한 성능을 가진다.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.387-397
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• 2003

Generally, most of researches that need a variable-clustering process use an exploratory factor analysis technique or a divisive hierarchical variable-clustering method based on a correlation matrix. And some researchers apply a object-clustering method to a distance matrix transformed from a correlation matrix, though this approach is known to be improper. On this paper an agglomerative hierarchical variable-clustering method based on a correlation matrix itself is suggested. It is derived from a geometric concept by using variate-spaces and a characterizing variate.