• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.382-390
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• 2016

Since it is favorable to include the incipient caries lesion in the diagnostic criteria in adolescence, this study had surveyed dental caries status of adolescents at ages of 13 and 16 by using WHO basic methods and ICDAS-II codes. In this study, mean DMFT index was 3.71, and mean DT index was 1.94. For both indices, the age 16 group showed higher values than the age 13 group. By groups of teeth, DMFT index and DT index exhibited highest to the lowest values in molar, premolar, and anterior teeth, respectively. 77.46% of total numbers of teeth were classified as code 0 in ICDAS-II. Compared to anterior teeth, numbers of decayed teeth were increased in posterior teeth. All caries lesions in anterior teeth and premolars were limited to enamel. ICDAS-II code is an useful method to detect the incipient caries lesion, allowing preventive control on caries management.

• Journal of Wetlands Research
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• v.23 no.2
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• pp.133-143
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• 2021

This study aims to classify the plant communities of the Gudam wetland, a riparian wetland in Nakdong River basin, and to identify the characteristics of the communities according to the veritical structure to prepare management plan. In the Gudam wetland, a total of 19 plant communities were found through physiognomical vegetation, and were analyzed by dividing into tree dominant community, shrub dominant community, and herbaceous dominant community according to the vertical structure. When examining the results of the community characteristics analysis, the species diversity index was the highest in the tree dominant communities but there was concern about a decrease in species diversity due to the influx of exotic plants such as Sicyos angulatus. The shrub dominant community tended to have a biased species diversity index on shrub plants. The herbaceous dominant communities ware divided into wetland herbaceous communities and dryland herbaceous communities according to the species diversity index, and measures were needed to reduce the species diversity index due to artificial disturbances. The importance value was the highest in the arboreal Salix genus in the tree dominant communities, and the exotic plants such as Amorpha fruticosa were the highest in the shrub dominant communities. In the herbaceous dominant communities, wetland herbaceous plants such as Phragmites japonicus were high. As a result of the analysis according to ordination the tree dominant communities and shrub dominant communities were differentiated by exotic plant factors, and the herbaceous dominant communities were differentiated by hierarchy number and slope.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.426-433
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• 2013

The objective of this study was to examine whether there is an association of oral health conditions between mothers and their preschool children in Korea. A sample of 823 preschool children and their mothers were selected for this study from the database of the fourth Korean National Health and Nutrition examination Survey. Preschool children were defined as children aged 4, 5, and 6 years old. The subjects were clinically examined for the presence of caries lesions (dft index) and their mother was checked for the presence of dental caries (DMFT index) and periodontal status (CPI). The socio-demographic characteristics and mother's oral health behaviours were considered covariates in this study. Univariate and multivariate analysis was adapted to assess the association of oral health condition between mothers and their preschool children. In univariate analysis, there were significant differences between preschool children's dft index and their mother's age (p=0.005), dental treatment demand for the past one year (p=0.034), and DMFT index (p=0.016). In multivariate analysis, only mother's DMFT index was significantly associated with their children's dft index after adjusting for covariates. In conclusion, the mother's oral health was partly associated with their preschool children's oral health in Korea.

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.301-308
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• 2016

The process capability index is used to determine whether a production process is capable of producing items within a specified tolerance. Some process capability indices $C_p$, $C_{pk}$ and $C_{pm}$ have been of particular interest as useful management tools for tracking process performance. Most evaluations on process capability indices focus on statistical estimation and test of hypothesis. It is necessary to investigate their asymptotic correlationship among basic estimators ${\hat{C}}_p$, ${\hat{C}}_{pk}$ and ${\hat{C}}_{pm}$ of process capability indices $C_p$, $C_{pk}$ and $C_{pm}$. In this paper, we study their asymptotic correlationship for three process capability indices ${\hat{C}}_p$, ${\hat{C}}_{pk}$ and ${\hat{C}}_{pm}$ under bivariate normal distribution BN(${\mu}_x,{\mu}_y,{\sigma}^2_x,{\sigma}^2_y,{\rho}$). With some nonnormal processes, the asymptotic correlation coefficient of any two respective process capability index estimators could be established.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.70.3-70.3
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• 2017

맑은 날에도 엷은 상층운이나 난류의 방해로 관측 품질이 저해되는 등 천문 분야는 대기환경에 민감하나, 하층 대기 상태에 비중을 두는 동네예보만으로는 천문 분야의 기상정보에 대한 수요를 충족하기에는 한계가 있다. 이에 천문 관측 환경에 보다 특화된 별밤예보를 개발하여 천체 관측 가능성과 천문 관측 자료의 품질을 좌우하는 대기상태를 UM 국지모델 생산자료를 바탕으로 예보하고자 한다. 예보 요소는 하늘상태(운량), 시상(seeing), 투명도, 암도(darkness) 및 대기청명지수, 풍속, 기온, 습도이다. 대기청명지수는 일반인이 관찰하기 좋은지 여부를 한 눈에 알 수 있게 운량과 투명도, 암도를 종합한 지수로 10~100까지 10단계로 제공할 계획이다. 하늘상태와 풍속, 기온, 습도는 $5{\times}5km$격자마다 제공되는 기상청 동네예보에서 천문대와 가장 가까운 격자의 예보치를 추출하였다. 시상은 대기의 난류 정도에 좌우된다. 그러나 충북의 고층기상 관측자료가 없어서, 시상 예보식을 만들기 위해 UM 국지모델에서 제공하는 각 등압면의 기온과 바람벡터로부터 정적 안정도(온위 경도)와 연직 바람시어를 유도한 뒤, 다중회귀분석으로 시상 예보식을 구하였다. 또한 대기청명지수는 청주기상지청에서 관측한 운량과 밤하늘 밝기 자료를 종속변수, 별의 개수를 독립변수로 하는 다중회귀예측식을 구하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.320-323
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• 2010

This paper proposes efficient log and exponent calculation methods using a dual phase instruction set without additional ALU unit for a mobile enviroment. Using the Dual Phase Instruction set, it extracts exponent and mantissa from expression of floating point and calculates 24bit single precision floating point of log approximation using the Taylor series expansion algorithm. And with dual phase instruction set, it reduces instruction excution cycles. The proposed Dual Phase architecture reduces the performance degradation and maintain smaller size.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.421-429
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• 2006

This study was undertaken to develop an analysis model representing a reliable estimation of rigidity of Korean soft clay using an artificial neural network (ANN). Data for the model development were obtained through a laboratory study, and were used for training and verification. The coefficient of correlation between the measured and predicted data using the developed model was relatively high. It demonstrates the potential application of ANN for the reliable estimation of Korean soft clay rigidity while past attempts at building such a mathematical model have proved difficult.

• Journal of Korea Water Resources Association
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• v.39 no.9 s.170
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• pp.801-812
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• 2006

In this study, Combined Drought Index which can monitor the drought severity and intensity has been developed using PDSI, SPI and MSWSI. To verify the accuracy and applicability of combined drought index, Drought map of Korea using the combined drought index has compared with past drought event. Drought map using the combined drought index shows good accordance with past drought event and accurate quantitative drought monitoring results. Also the drought outlook technique has been developed using the weather forecast data of Korea Meteorological Administration (KMA). Drought outlook technique of this study can be used effectively as a primitive stage tool for real time drought forecast. As a result of this study, Integrated drought monitoring system has been developed which has capabilities of producing and generating the drought monitoring map and drought outlook map as well as various kinds of drought related information.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.11-24
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• 2009

The process controller in the adjustment procedure is often used effectively to control the process level close to target when noise is present and unremovable. Examples of the robust controller are single EWMA controller and double EWMA controller. Double EWMA controller is designed to reduce the offset of the process deviation, which single EWMA can not eliminate. In this paper, the two controllers are modified by taking EWMA of the original controller to reduce the adjustment variance, which may become excessively large when the two given controllers are implemented. It is shown that the EWMA modification of the given controllers is successful in reducing the adjustment variance, while the mean squared deviation increases slightly.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.439-447
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• 2004

The aim of this study is to survey the frequency of mutans streptococci species and biotypes isolated from dental plaque in Korean children and the relationship between species and biotypes of mutans streptococci and dft index. Dental plaques were collected from the anterior and molar teeth of upper and lower jaws in the subjects, aged below 12 years old. A dental examination was performed for dft (decayed, filled, total) with the WHO caries diagnostic criteria. The mutans streptococci from the sample were cultured selectively on mitis salivarius-bacitracine (MSB) agar plate. For biotyping of mutans streptococci, biochemical test was performed. From the culture, bacterial genomic DNA was prepared for using of PCR template for the identification of mutans streptococci at the species-level. Forty strains of mutans streptococci were isolated from dental plagues of 40 patients. The biotype I (45%) and biotype IV (32.5%) were most frequently detected. The prevalence of S. mutans and S. sobrinus was 69% and 31%, respectively. There was no positive relationship between species and biotypes of mutans streptococci and dft index. Our results revealed that biotype I and S. mutans were frequently detected in Korean children and support that dental caries incidents by many causative factors not only bacterial factor.