• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.384-393
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• 2012

Saemangeum lake is an artificial lake created by reclamation works and an estuary embankment since 2006. The sea water flows into the lake by the operation of two sluice gates, and the freshwater enters into the lake by the upper streams. For the reflection of hydrology and hydrodynamics effects in Saemangeum area, a hydrodynamics model was developed by connecting Hydrological Simulation Program with Fortran (HSPF) and Environmental Fluid Dynamic Code (EFDC). The HSPF was applied to simulate the freshwater discharge from the upper steam watershed, and the EFDC was performed to compute water flow, water temperature, and salinity based on time series from 2008 to 2009. The calibration and validation are performed to analyze horizontal and vertical gradients. The horizontal trend of model simulation results is reflected in the trend of observed data tolerably. The vertical trend is conducted an analysis of seasonal comparisons because of the limitation of vertically observed data. Water temperature reflects on the seasonal changes. Salinity has an effect on the near river input spots. The impact area of salinity is depending on the sea water distribution by gate operation, mainly.

• KIEAE Journal
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• v.14 no.5
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• pp.111-116
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• 2014

Han-ok has been forgotten by rapid industrialization, however, recent interest in Korean traditional culture and eco friendly architecture are increasing. Government is also processing various policies and research in Han-ok for historical reasons. Still Han-ok is considered as temporary discover stage not daily space. Moreover, previous weakness of Han-ok made it difficult to supply. There is a need to build new Han-ok style public buildings different from traditional or new Han-ok for revitalization of Han-ok. Moreover, development of new Han-ok style public buildings model are needed for the public which include updated concept and function. From public buildings model development and supply people can visit and explore Han-ok. Therefore Han-ok tradition can be modernized. In addition to this Korean traditional culture and mode of living can be developed and conserved. This research focuses on public buildings of Han-ok supplication and aims design elements and regional trend.

• Journal of Ecology and Environment
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• v.34 no.2
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• pp.203-214
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• 2011

The objectives of this research were to predict land-use/land-cover change at the Sakaerat Environmental Research Station (SERS) and to analyze its consequences on the distribution for Black-crested Bulbul (Pycnonotus melanicterus), which is a popular species for bird-watching activity. The Dyna-CLUE model was used to determine land-use allocation between 2008 and 2020 under two scenarios. Trend scenario was a continuation of recent land-use change (2002-2008), while the integrated land-use management scenario aimed to protect 45% of study area under intact forest, rehabilitated forest and reforestation for renewable energy. The maximum entropy model (Maxent), Geographic Information System (GIS) and FRAGSTATS package were used to predict bird occurrence and assess landscape fragmentation indices, respectively. The results revealed that parts of secondary growth, agriculture areas and dry dipterocarp forest close to road networks would be converted to other land use classes, especially eucalyptus plantation. Distance to dry evergreen forest, distance to secondary growth and distance to road were important factors for Black-crested Bulbul distribution because this species prefers to inhabit ecotones between dense forest and open woodland. The predicted for occurrence of Black-crested Bulbul in 2008 covers an area of 3,802 ha and relatively reduces to 3,342 ha in 2020 for trend scenario and to 3,627 ha for integrated-land use management scenario. However, intact habitats would be severely fragmented, which can be noticed by total habitat area, largest patch index and total core area indices, especially under the trend scenario. These consequences are likely to diminish the recreation and education values of the SERS to the public.

• Structural Engineering and Mechanics
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• v.66 no.6
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• pp.677-691
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• 2018

Reliability assessment of complex structures using simulation methods is time-consuming. Thus, surrogate models are usually employed to reduce computational cost. AK-MCS is a surrogate-based Active learning method combining Kriging and Monte-Carlo Simulation for structural reliability analysis. This paper proposes three modifications of the AK-MCS method to reduce the number of calls to the performance function. The first modification is related to the definition of an initial Design of Experiments (DoE). In the original AK-MCS method, an initial DoE is created by a random selection of samples among the Monte Carlo population. Therefore, samples in the failure region have fewer chances to be selected, because a small number of samples are usually located in the failure region compared to the safe region. The proposed method in this paper is based on a uniform selection of samples in the predefined domain, so more samples may be selected from the failure region. Another important parameter in the AK-MCS method is the size of the initial DoE. The algorithm may not predict the exact limit state surface with an insufficient number of initial samples. Thus, the second modification of the AK-MCS method is proposed to overcome this problem. The third modification is relevant to the type of regression trend in the AK-MCS method. The original AK-MCS method uses an ordinary Kriging model, so the regression part of Kriging model is an unknown constant value. In this paper, the effect of regression trend in the AK-MCS method is investigated for a benchmark problem, and it is shown that the appropriate choice of regression type could reduce the number of calls to the performance function. A stepwise approach is also presented to select a suitable trend of the Kriging model. The numerical results show the effectiveness of the proposed modifications.

• Nutrition Research and Practice
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• v.12 no.5
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• pp.443-448
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• 2018

BACKGROUND/OBJECTIVES: This study was conducted to investigate the effects of sodium-potassium ratio on insulin resistance and sensitivity in Korean adults. SUBJECTS/METHODS: Subjects were 3,722 adults (1,632 men and 2,090 women) aged 40-69 years participating in the Korean genome and epidemiology study_Ansan and Ansung study. Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HoMA-IR) and fasting insulin, and insulin sensitivity was assessed by using the quantitative insulin sensitivity check index (QUICKI). The 24-h urinary sodium and potassium excretion were estimated from spot urinary samples using the Tanaka formula. The generalized linear model was applied to determine the association between urinary sodium-potassium ratio and insulin resistance. RESULTS: HoMA-IR (P-value = 0.029, P-trend = 0.008) and fasting insulin (P-value = 0.017, P-trend = 0.005) levels were positively associated with 24-h estimated urinary sodium-potassium ratio in the multivariable model. QUICKI was inversely associated with 24-h estimated urinary sodium-potassium ratio in all models (P-value = 0.0002, P-trend < 0.0001 in the multivariate model). CONCLUSION: The present study suggests that high sodium-potassium ratio is related to high insulin resistance and low insulin sensitivity. Decreasing sodium intake and increasing potassium intake are important for maintaining insulin sensitivity. Further studies are needed to confirm these findings in longitudinal studies.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.73-77
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• 2004

종속변수와 독립변수 사이의 통계적인 관계를 설명하기 위해 사용되는 회귀모형을 분석하는 방법을 회귀분석이라 한다. 독립변수와 종속변수가 퍼지수인 퍼지회귀모형을 추정하기 위해 최소전대편차추정량을 제시하고. 예제를 이용하여 퍼지최소절대편차회귀모형과 퍼지최소자 승회귀모형의 효율성을 평가한다.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.93-101
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• 1995

We present a brief survey concerning the relations between mean residual life and failure rate. Change points of mean residual life and failure rate are known to be different in general and we explore such situations in this paper. A few parametric models which show bathtub-shaped failure rate are examined in details, including the shape of its corresponding mean residual life function. We give some graphical comparisons of trend changes of mean residual life and failure rate for various choices of parameters for each parametric model.

• Communications for Statistical Applications and Methods
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• v.9 no.1
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• pp.175-185
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• 2002

A method is proposed for efficiently estimating the mean of a population which has a linear trend. The proposed estimator is based on the centered modified systematic sampling method and the concept of interpolation. Using the expected mean square error criterion, it is shown that the proposed method is more efficient than conventional methods in most real cases.

• Korea journal of population studies
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• v.23 no.1
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• pp.197-215
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• 2000

이 논문에서는 선형·비선형 성장곡선모형의 종류와 특성을 살펴보고, 이들을 비교·검토하고, 모형선호기준 통계량에 입각하여 추정결과를 비교한다. 또한 최종사용자 환경을 위한 SAS/AF로 구현한 성장곡선모형에 의한 인구예측시스템을 소개한다.

• Journal of the Korean Data and Information Science Society
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• v.10 no.1
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• pp.91-102
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• 1999

A new method is developed for estimating the mean of a population which has a linear trend. The suggested estimator is based on the balanced systematic sampling method and the concept of interpolation and extrapolation. The efficiency of the proposed method is compared with that of conventional methods.