• Tuberculosis and Respiratory Diseases
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• v.59 no.6
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• pp.600-605
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• 2005

Background : Primary multidrug-resistant tuberculosis is defined as Mycobacterium tuberculosis isolates that are resistant to at least isoniazid and rifampin in never-been-treated tuberculosis patients, and this malady is caused by the transmission of a resistant strain from one patient, who is infected with a resistant Mycobacterium tuberculosis strain, to another patient. The prevalence of primary multidrug-resistant tuberculosis could be a good indicator of the performance of tuberculosis control programs in recent years. We conducted a case-control study to identify the risk factors for primary multidrug-resistant tuberculosis. Methods : From January 1, 2001 to, June 30, 2003, by conducting prospective laboratory-based surveillance, we identified 29 hospitalized patients with P-MDRTB and these patients constituted a case group in this study. The controls were represented by all the patients with culture-confirmed drug susceptible tuberculosis who were admitted to National Masan Hospital during the same study period. The odds ratios for the patients with primary multidrug-resistant tuberculosis, as compared with those of the patients with drug susceptible tuberculosis, were calculated for each categorical variable with 95% confidence intervals. Results : Multivariate logistic regression showed that the presence of diabetes mellitus (odds ratio 2.68; 95% confidence interval, 1.05-6.86) was independently associated with having primary multidrug-resistant tuberculosis. Conclusion : This study has shown that diabetes mellitus might be one of the risk factors for primary multidrug-resistant tuberculosis.

• Journal of agricultural medicine and community health
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• v.34 no.2
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• pp.223-233
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• 2009

Objectives: This study aimed to examine the relations between exposure to anti-smoking promotion media and smoking, targeting middle school students who were exposed to various media of promotion. Methods: The subjects of the study were 38,820 middle school students who answered to the 2007 Korea Youth Risk Behavior Web-based Survey. Answers of 37,714 subjects were used for the final analysis except those of 1,106 that could not be used to judge anti-smoking promotion media and prevalence of smoking as they were considered insincere to the questions. We used SPSS of version 17.0. This study conducted a chi-square test to identify smoking rate according to characteristics of subjects and a multivariate logistic regression analysis to identify whether they are independently significant. Results: Smoking rate increased as the subjects were in higher grades. From the results of multivariate logistic regression, odds ratio(OR) at points 5~6 of the first graders that had never been exposed to anti-smoking promotion media was 0.49(95% CI=0.33-0.74), which was significantly low. And OR at points 5~6 of the third graders was 0.57(95% CI=0.43-0.76), significantly low. Conclusions: This study identified the relations between exposure to anti-smoking promotion media and smoking of middle school students in Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.526-534
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• 2014

In this study, single-input transfer function model is applied to forecast monthly mean sea surface temperature(SST) in 2010 at Yeosu in Korean coastal waters. As input series, monthly mean air temperature series for ten years(2000-2009) at Yeosu in Korea is used, and Monthly mean SST at Yeosu station in Korean coastal waters is used as output series(the same period of input). To build transfer function model, first, input time series is prewhitened, and then cross-correlation functions between prewhitened input and output series are determined. The cross-correlation functions have just two significant values at time lag at 0 and 1. The lag between input and output series, the order of denominator and the order of numerator of transfer function, (b, r, s) are identified as (0, 1, 0). The selected transfer function model shows that there does not exist the lag between monthly mean air temperature and monthly mean SST, and that transfer function has a first-order autoregressive component for monthly mean SST, and that noise model was identified as $ARIMA(1,0,1)(2,0,0)_{12}$. The forecasted values by the selected transfer function model are generally $0.3-1.3^{\circ}C$ higher than actual SST in 2010 and have 6.4 % mean absolute percentage error(MAPE). The error is 2 % lower than MAPE by ARIMA model. This implies that transfer function model could be more available than ARIMA model in terms of forecasting performance of SST.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.299-305
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• 2011

Purpose: In watching 3D stereoscopic display using the binocular disparity, effect of difference of the pupillary distance between the adults and children on the perception of depth were investigated. Methods: The average PD of children was determined from the PD measurements of children of the elementary school of 2nd and 3rd grade in Seoul. The location of crossing visual axes were derived from the relation of the binocular disparity and the PD for the adults and children. Results: The average PD of the children was measured to be 57.3 mm which was smaller than the average PD of the adults that was known to be about 65 mm. As the binocular disparity increases to the positive direction, the crossing location steeply moves farther behind the screen. On the other hand, when the binocular disparity increases to the negative direction, the crossing location gradually moves toward the viewer. For the same amount of the binocular disparity, the crossing locations were derived to be larger for the children than the adults due to the difference of the PD. Therefore, children will perceive larger depth than the adults. Conclusions: Small PD of the viewer causes the larger amount of the depth perception. In producing the stereoscopic images, the average PD of children as well as adults need to be considered.

• Korean Public Health Research
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• v.44 no.4
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• pp.35-49
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• 2018

Objective : The purpose of this study was to investigate the risk factors of dehydration from the subjects who underwent anthropometric and blood parameters testing during a comprehensive health screening. Methods : For the study analysis, 5,391 samples with valid data of the levels of Sodium($Na^+$), BUN (Blood Urea Nitrogen) and FBS(Fasting Blood Sugar) were selected to calculate a dehydration indicator of plasma osmolality. The study data was collected from the health screening examinees who visited Sahmyook Medical Center Seoul Adventist Hospital Comprehensive Health Check-up Center from 2014.01.01 to 2015.12.31. The relationship between dehydration and age group, BMI, disease exposures(hypertension, diabetes mellitus, dyslipidemia, kidney disorder) were analyzed by gender. Results : The odds ratio of dehydration showed statistical significance from age ${\geq}50$ in both male and female, respectively. The female obese group was vulnerable to dehydration while the male study group showed no statistical significance in the BMI difference. The disease exposed groups(hypertension, diabetes mellitus, dyslipidemia, kidney disorder) were vulnerable to dehydration. Also, the more types of disease carried by the exposed patients, the higher odds ratio and susceptibility to dehydration. Conclusions : Aging, increasing BMI, and exposed to diseases were found to be the risk factors for vulnerability to dehydration. To prevent dehydration, special caution to be taken for those in the ${\geq}50s$ group, along with controlling BMI and chronic diseases. Further studies are suggested to investigate the risk factors of dehydration that may affect increasing plasma osmolality as a potential stimulus mechanism in disease outbreaks.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.95-102
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• 2022

The relationship between lipoprotein(a) and dyslipidemia is not clear. This study was therefore undertaken to investigate the relationship between lipoprotein(a) and dyslipidemia in elderly patients over 60 years. From 2014 to 2020, a total of 2,580 adults aged 60 years or older (73.31±7.24 years, 1,954 males) were enrolled in the study. The patients had checked into a general hospital, and data were obtained for lipoprotein(a), LDL-C, TG, HDL-C, hs-CRP, HbA1c, sex, age, BMI, dyslipidemia diagnosis, and use of lipid-lowering agents. BMI and HbA1c showed no correlation with lipoprotein(a), but hs-CRP (r=0.138), LDL-C (r=0.097), HDL-C (r=-0.089), TG (r=-0.073), and age (r=0.072) were significantly correlated to lipoprotein(a). The partial correlation between lipoprotein(a) and LDL-C, which was adjusted for variables, was significant only in the male gender (r=0.158, P<0.001). As the odds ratio of the 4^th quartile of lipoprotein(a) (OR=1.376, 95% CI=1.038~1.822) for dyslipidemia was found to be significant in this study when the level of LDL-C, the primary target, could not be reduced even by taking lipid-lowering drugs, we propose that lipoprotein(a) should also be included among the several factors considered as secondary targets. Our results indicate that studies on various lipid factors considering the sex, age, types and use of lipid-lowering agents, are warranted.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.79-88
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• 2024

We used actual field data to analyze from a traffic engineering perspective how AI and edge computing technologies affect the reduction of traffic accidents. By providing object information from 20m behind with AI object recognition, the driver secures a response time of about 3.6 seconds, and with edge technology, information is displayed in 0.5 to 0.8 seconds, giving the driver time to respond to intersection situations. In addition, it was analyzed that stopping before entering the intersection is possible when speed is controlled at 11-12km at the 10m point of the intersection approach and 20km/h at the 20m point. As a result, it was shown that traffic accidents can be reduced when the high object recognition rate of AI technology, provision of real-time information by edge technology, and the appropriate speed management at intersection approaches are executed simultaneously.

• The Korean Journal of Applied Statistics
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• v.15 no.2
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• pp.311-321
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• 2002

Transfer function model(TFM) capturings conditional heteroscedastic pattern is introduced to analyze stochastic regression relationship between the two time series. Nonlinear ARCH concept is incorporated into the TFM via threshold ARCH and beta- ARCH models. Steps for statistical analysis of the proposed model are explained along the lines of the Box & Jenkins(1976, ch. 10). For illustration, dynamic analysis between KOSPI and NASDAQ is conducted from which it is seen that threshold ARCH performs the best.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.247-250
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• 2004

본 논문은 비선형 시스템의 새로운 퍼지 제어기 설계 기법을 제안한다. 퍼지 제어기는 비선형 시스템을 제어하는데 많이 사용되는 기법 중에 하나이다. 퍼지 제어기를 설계하는 것은 시스템에 대한 깊은 수학적인 접근이 필요로 하기 때문에 수학적 배경 없이 설계하기 힘들다. 본 논문에서는 이를 해결하기 위해 길은 수학적인 접근이 아닌 지능적인 접근 방법을 사용하여 안정화된 퍼지 제어기의 설계하는 기법을 제안한다. 제안된 기법은 퍼지 제어기의 안정화 조건을 만족시키는 제어 파라메터를 전략 기반 유전 알고리즘을 사용하여 동정한다. 전략 기반 유전 알고리즘은 제어기의 안정화 조건을 만족시키는 해를 찾기 위해 전략적으로 교차와 돌연변이를 변화시킨다. 최종적으로 모의 실험을 통해 제안된 기법의 우수성을 확인한다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.4 no.4
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• pp.43-51
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• 1990

레이저 비임이 대기중을 전파할 때 고류(turbulence)의 영향을 고려해야 한다. 고류의 영향에 의한 프린지 시도는 extended Huygens-Fresnel principle을 도입하여 타원체로 간주할 수 있는 프린지 체적에서 장의 전 분포를 시하고 이 전 분포로부터 평균 강도분포를 얻었으며, 평균 강도분포를 구하기 위해 Fourier-Bessel적분을 행하였다. 평균 강도분포에서 최대 평균 강도분포max 및 최소 평균 강도분포 min을 얻었으며, 이 식들을 프린지 시도의 정의 식 V=(Imax-Imax)/(Imax+Imin)에 적용하였다. 본 논문에서는 광원으로 파장 =4880[]인 아르곤 레이저를 사용하였고 광원의 모우드는 TEM..모우드로 하였다. 또한 비임의 교각 =5˚, 광원으로부터 프린지 체적 까지의 거리 L=10[m], en 광원간의 거리 B=(2tan /2)L, 특성 비임 반경 =2 /[ ( /2)]을 이용하여 프린지 시도에 관한 결과를 얻었으며, 이 결과에 의하면 L'( / ·L)에 대한 변수 r의 비 r/L'= 에서 V=1이고, r/L=0.1에서 프린지 시도가 감소한다. 또 강 고 류인 경우와 약 고 류인 경우에 대해 프린지 시도를 비교하였을 때 강 고류에서 감소폭이 크다는 사실을 알 수 있었다.