• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.4
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• pp.369-374
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• 2015

In order to efficiently optimize the problem involving complex computer codes or computationally expensive simulation, surrogate models are widely used. Because their accuracy significantly depends on sample points, many experimental designs have been proposed. One approach is the sequential design of experiments that consider existing information of responses. In earlier research, the correlation coefficients of the kriging surrogate model are introduced as weight parameters to define the scaled distance between sample points. However, if existing information is incorrect or lacking, new sample points can be misleading. Thus, our goal in this paper is to propose a weight function derived from correlation coefficients to generate new points robustly. To verify the performance of the proposed method, several existing sequential design methods are compared for use as mathematical examples.

• Journal of Korea Water Resources Association
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• v.42 no.2
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• pp.131-139
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• 2009

The weather accidents by global warming effect are increasing rapidly whole world. Flood forcasting system and hydrological database are operated by almost all the countries in the world. An objective of this study is to research revised methods of missing rainfall data and find more effective revised method for this operating system. 194 rainfall data of the Han river basin is used. Arithmetic average method, coefficient of correlation weighting method and inverse distance weighting method are compared to estimate revised methods. The result from the analysis shows that coefficient of correlation weighting method is best quantitatively among the 3 methods.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.343-347
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• 2010

This paper presents an efficient image recognition method using the hybrid coefficient measure of correlation and distance. The correlation coefficient is applied to measure the statistical similarity by using Pearson coefficient, and distance coefficient is also applied to measure the spacial similarity by using city-block. The total similarity among images is calculated by extending the similarity between the feature vectors, then the feature vectors can be extracted by PCA and ICA, respectively. The proposed method has been applied to the problem for recognizing the 960(30 persons * 4 expressions * 2 lights * 4 poses) facial images of 40*50 pixels. The experimental results show that the proposed method of ICA has a superior recognition performances than the method using PCA, and is affected less by the environmental influences so as lighting.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.45-45
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• 2022

산업화에 따른 화학물질 사용량의 증가는 담수로의 유해화학물질 유출사고의 위험을 증가시키며, 이러한 사고는 하천수 수질과 수환경 생태계에 심각한 위해와 손상을 야기한다. 이러한 수질사고 발생시 신속 대응을 위해, 하천에 유입된 물질의 거동을 신속하게 예측하는 것이 필요하며 이 경우 1차원 추적모형이 주로 사용된다. 1차원 물질혼합 모형은 하천을 하나의 유선으로 보며, 복잡한 하천흐름의 시스템을 현상학적으로 해석하고, 오염물질의 이송 및 혼합 메카니즘을 모델 매개변수에 반영하여 모형화한다. 이러한 매개변수들은 직접적으로 측정하기 어려우며, 이론에 기반한 매개변수 산정 기법이 구축되지 않은 실정이다. 따라서 대부분의 연구에서는 추적자 실험을 실시하여 유한한 하천구간에서 추적자의 시간-농도곡선(Breakthrough curve, BTC)을 취득하고, 이를 통하여 대상 구간의 매개변수를 역산하는 최적화 기법에 의존하고 있다. 하지만, 모든 하천구간에 대하여 추적자 실험을 수행하여 데이터를 확보하는 것이 어렵기 때문에 최적화 기법의 적용성에 한계가 있다. 본 연구는 흐름정보가 제공되지 않은 미계측 하천구간에서 BTC를 신속하게 예측할 수 있는 회귀모형을 구축하는 것을 목표로 한다. 국내 하천에서 수행한 4회의 추적자 실험으로부터 취득한 28개 구간 케이스의 데이터에 대하여 농도곡선 전처리를 수행하고 14개의 통계적 특징을 추출하였으며, 계측된 흐름특성과의 상관관계를 분석하였다. 분석 결과, 대상 구간에서의 BTC의 변화가 추적자의 유하거리에 매우 높은 상관관계를 보였으며, 이를 이용하여 회귀모형을 제시하였다. 제안된 회귀모형을 적용하여 하류의 지점에서의 BTC를 예측하였으며, 1차원 이송-분산 방정식과 하천저장대모형을 활용한 예측결과와 비교하여 검증하였다. 그 결과, BTC의 변화특성을 활용한 회귀적 예측이 하천 지형 및 흐름의 변동성이 작은 구간에서 1차원 혼합모형들을 이용한 예측보다 더 높은 정확도를 보였으며, 이러한 장점은 장거리 예측에서 더 분명하게 나타났다.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.113-123
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• 2001

The main purpose of this study was to provide information on attenuation effects in forest tree belt of pine stand and oak stand. The relationships between DBH, tree height, clear length, crown area and number of trees and also between distance from noise origin, landslope etc. were analysed by correlation and multiple regression. The results obtained were as follows : 1. There was no difference between pine stand and oak stand in effecting noise attenuation. 2. The noise pressure was highly correlated with all of seven elements tested and both DBH and distance from noise origin have higher r-values than the others. For the pine stand, it was 0.9133 in DBH and 0.9630 in the distance and for the oak stand, 0.9296 in DBH and 0.9565 in the distance. 3. The optimum regression equation for pine stand and oak stand were made by combination of two variables (DBH and distance). The table of noise attenuation was made by optimum regression equation. In the case of pine stand, the attenuation ratio was 29% at 5m, 31.6~32.6% at 10m, 38.3~39.8% at 20m and 45.2~46.6% at 30m. And case of oak stand, the attenuation ratio was 29% at 5m, 31.6~34.2% at 10m, 38.6~41.4% at 20m and 45~47.2% at 30m. 4. As the noise pressure limit at the Urban housing area according to environmental laws is under 55dB, it is suggested by the table of noise attenuation that the distance, and DBH for the pine and oak stand are over 20m, 400cm and 30-35 trees, respectively.

• Journal of Veterinary Clinics
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• v.17 no.2
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• pp.388-394
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• 2000

이 실험은 소형견종에 대한 정상 SEPs의 범위를 알아내기 위해 실시되었다. 임상증 상이 정상인 28두를 대상으로 자극점에서 channel 1 까지의 Pl(LPI), channel 1까지의 Nl (LN1), 자극점에서 channel 2가지의 Pl(TP1), channel 2까지의 N1(TNI)의 절대잠복기와 LP1-TN1` 의 파간잠복기를 알아내기 위해서 실시하였다. 이번 실험에서 LPI, LNI, TPI, TNI의 절대잠복기 (absolute latency)의 평균값은 2.69$\pm$0.31 msec, 4.91$\pm$0.49m/sec, 4.64$\pm$0.39 msec, 5.21$\pm$0.42 msec 띠었다. LP1과 TN1 사이의 파간절대잠복기의 핑균값은 2.52$\pm$7.19 msec 이었다. 측정 치들을 속도로 변환하였을 경우 다음과 같았다. 측, LPI, LNI. Tfl, TNI 그리고 LP1-TN1 에서의 속도의 평균값은 각각 93.11$\pm$ 8.58 m/sec, 50.99$\pm$ 5.36m/sec. 80.18$\pm$ sec, 71.31$\pm$4.79m/sec그리고 49.50$\pm$3.58m/sec 이었고. 71.66m/sec, 37.79m/sec, 65.75m/ sec, 59.33 m/sec, 40.55m/sec 의 최저속도를 초과하였을 때 정상범위로 간주하였다. LPI, LNI, TPI,TN1까지의 절대잠복기와 자극전극에 시 측정전극가지의 거리 사이에는 상관관계가 있었다 LP1, LN1, TP1, TN1의 상관계수는 각각 0.621, 0.494. 0.577,0.618 이었다 요추에서 기록된 SEPs갈은 LP1의 상관계수가 LN1 보다 높았으며 흉추에서 기록된 SEPs값은 TN1의 상관계수가 TP1보다 높았다. LP1과 TN1의 파간잠복기와 channel 1과 2의 거리차이와의 상관계수는 0.571이다. 따라서 LPI, LNI. TPI, TNI그리고 LPI-TNI 들의 최저속도를 이용 하여 척수 손상 여부를 판단할 수 있다고 생각된다.

• Geotechnical Engineering
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• v.13 no.1
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• pp.19-34
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• 1997

Applications of geostatistical method to cone penetrometer data have been performed at the overconsolidated clay site. Randomlylocated 28 electronic CPT soundings (Location A) and consistently-located 38 CPT soundings(Location B) are investigated geostatistically. Variograms for Locations A and B have been developed for q, from the CPT data by using "kriging" principles, which establish the horizontal and vertical correlation distrances at this site. These vertical and horizontal correlation distances can be used to optimal sampling design, where, if one needs to compare two test results, sampling must be made within these vertical and horizontal correlation distances. Analysis of the variograms indicated that the geological formation between two locations are not very different in both vertical direction and horizontal direction.direction.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.310-317
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• 2015

Purpose: The purpose of this study was to evaluate the validity of reference points for edentulous patient by examining the correlation of teeth and face, and intraoral anatomic landmarks. Materials and methods: We examined a facial outline, length, bizygomatic width, nasion - gnathion length, glabella - nasion distance in 270 men and 280 women satisfied with inclusion criteria from Seoul National School of Dentistry. The shape of maxillary central incisor, mesiodistal crown width and length of maxillary 6 incisors, distance from incisive papilla to labial surface of maxillary central incisor, and perpendicular distance from incisive papilla to intercanine line were measured in the stone model. We analyzed the ratio and relevant relation statistically. Results: The probability on having the same shape of face and the relative same shape maxillary incisor was 55.56% and 46.43% for men and women. The facial length proved to be a more valuable measurement in women in the tooth selection. The ratio of bizygomatic width to mesiodistal width of maxillary central incisor, and the ratio of bizygomatic width to width of maxillary 6 incisors were 16.8 : 1 and 3.0 : 1 and were positively correlated with each other. The distance of the canines from the maxillary incisal papilla was $1.33{\pm}1.28mm$. The distance between the center of the incisal papilla and the labial surface of their maxillary central incisor was $9.23{\pm}1.20mm$. Conclusion: It was showed that anatomical reference points in tooth selection and arrangement for edentulous patient are useful and have validity in our limited study.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.115-122
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• 1999

In this paper, we confirmed that a speech signal is a chaos signal, and in order to use it as a speaker recognition parameter, analyzed chaos dimension. In order to raise speaker identification and pattern recognition, by making up the strange attractor involving an individual's vocal tract characteristics very well and applying fuzzy membership function to correlation dimension, we proposed fuzzy correlation dimension. By estimating the correlation of the points making up an attractor are limited according space dimension value, fuzzy correlation dimension absorbed the variation of the reference pattern attractor and test pattern attractor. Concerning fuzzy correlation dimension, by estimating the distance according to the average value of discrimination error per each speaker and reference pattern, investigated the validity of speaker recognition parameter.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.45-54
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• 2006

The Purpose of this Paper is to compare and analyze the operational condition of corporation-owned and owner-driver taxies using tachometer output data. The empirical findings from this study are as follows : First, although corporation-owned taxies have long operating mileage and service driving mileage per vehicle. the service rate of owner-driver taxies were 3.5 percent higher than corporation-owned taxies. Secondly it is found that operation mileage, service driving mileage, and service Income except non-service driving mileage have statistically significant differences between corporation owned and owner-driver taxies. In addition. there was a weak correlation between the income and non-service driving mileage of owner-driver taxies. It is concluded that owner-driver taxies joined the call-taxi association and call-taxi services decreased non-service driving mileage.