• Journal of Nutrition and Health
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• 제33권2호
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• pp.202-215
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• 2000

Intake frequency of one food is often associated with other food items, but few studies examined the relationship of food intake frequency among food items. Finding the relationship among intake frequencies of different food might be useful to understand the food intake patterns of population and correlated foods would be used as an indicators of another food intake. Relationship of food intake can be also applied to make a more simple and useful form of food frequency questionnaire to assess the association between diet and various diseases. The objective of this study was to examine the correlation of intake frequency among food items in food frequency questionnaire (FFQ). A FFQ with 84 food items was administered to 14533 Korean males who 40-65 years of age participating Korean cancer research survey. Data fromm 7647 subjects who completed FFQ were used to examine correlation among food items with three different methods-log linear regression models, Spearman correlation coefficients and cell frequency distribution. To examine the rank correlation, coefficients were calculated by Spearman correlation after scoring the frequency categories. Three most correlated foods were selected in every food intems by three methods each. In most food items, there was positive correlatin, except cooked rice and cooked brown rice, in intake frequency between foods that belonged to similar food groups. But serveral food items-Sausage (processed fish, cheese), Milk (whilte bread, orange juice), Soymilk(other juices), Cheese (pizza, butter), and Coffee(thick beef soup)-showed correlation among totally different food groups. Two sets of food items which were selected by log linear regression model and Sperman correlation coefficients were compared. There were exactly three common foods in 18 food items, 2 common foods in 47 items, 1 common food in 16 items and no common food in 3 items among 3 ranked foods. Three sets of selected food were compared. There were exactly three common foods in 5 food items, 2 common foods in 21 items, 1 common food in 34items and no common food in 24 items among 3 ranked foods. These results indicate that certain patterns exist among intake frequencies of specific food items in the FFQ. More researches are suggested to understand the relationshiops among the intakes of foods so that this information can be used in developing better FFQ or analyzing missing items from self-administered FFQ.

• Genomics & Informatics
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• 제14권4호
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• pp.160-165
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• 2016

Over the past decade, the detection of gene-gene interactions has become more and more popular in the field of genome-wide association studies (GWASs). The goal of the GWAS is to identify genetic susceptibility to complex diseases by assaying and analyzing hundreds of thousands of single-nucleotide polymorphisms. However, such tests are computationally demanding and methodologically challenging. Recently, a simple but powerful method, named "BOolean Operation-based Screening and Testing" (BOOST), was proposed for genome-wide gene-gene interaction analyses. BOOST was designed with a Boolean representation of genotype data and is approximately equivalent to the log-linear model. It is extremely fast, and genome-wide gene-gene interaction analyses can be completed within a few hours. However, BOOST can not adjust for covariate effects, and its type-1 error control is not correct. Thus, we considered two-step approaches for gene-gene interaction analyses. First, we selected gene-gene interactions with BOOST and applied logistic regression with covariate adjustments to select gene-gene interactions. We applied the two-step approach to type 2 diabetes (T2D) in the Korea Association Resource (KARE) cohort and identified some promising pairs of single-nucleotide polymorphisms associated with T2D.

• 대한산업공학회지
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• 제34권2호
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• pp.216-222
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• 2008

The determination of spectrum charges for the operators is a main issue to efficiently manage the limited radio spectrum resources. In this paper, we propose a model to compute the optimal charges for radio spectrum usage. The objective is to determine that will maximize the spectrum charges, and decision variables of ratios for actual or estimated revenues are considered. The spectrum charges are maximized under satisfying the least profit for operators based on Log-Linear demand function. The parameters of actual sales and minimum profit of operators are analyzed to make an efficient management for radio spectrum. The results show that the spectrum charges increase as the actual sales increase, but it decrease as the required minimum profit of operator increases. It is also observed that the government should increase the ratio for estimated sales if anticipating the poor market in the future, otherwise they should increase the ratio for actual sales to maximize the spectrum charges.

• Environmental Engineering Research
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• 제25권2호
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• pp.163-170
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• 2020

Knowledge of organic micropollutant transfers in barrier seal materials from waste storage facilities is limited to volatile organic compounds and phenolic compounds at ambient temperature. This study focused on the sorption of chlorophenols (CPs) from various geotextiles from clay geosynthetics under the influence of temperature. Also to study the impact of the polarity or the amount of CPs adsorbed on geotextiles with the partition coefficient. The effect of various parameters such as contact time, effect of temperature, initial CPs concentration and adsorbent dosage has been carried out in this study. The result obtained is non-linear and the data was calculated for affinity with Freundlich isotherm model. An important observation is that the amount of CPs sorbed on geotextiles increases with a growing number of chlorine atoms, ie increases with the partition coefficient (log K_ow). During this study, a decrease in adsorbent properties was observed with the rise in temperature from 23℃ to 55℃. The partitioning coefficients for CPs examined range are from 2.4 (R² = 0.86) to 8.4 mL/g (R² = 0.90). Among the CPs studied, the highest adsorbed quantity was observed for pentachlorophenol with 0.052 g/g at 23℃, this quantity will decrease with the increase in temperature.

• 응용통계연구
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• 제18권2호
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• pp.471-485
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• 2005

범주형 자료분석에서 차원축소(collapsibility)는 오즈비로 설명되었다. 실제의 $2{\times}2{\times}K$ 분할표 자료를 이 이론에 적응시켰을 때 오즈비의 값으로 차원축소가 가능한지의 여부를 판단하기는 어렵다. 오즈비를 시각적으로 표현하는 방법 중에서 Doi, Nakamura와 Yamamoto(2001)가 제안한 Contour plot을 통해서 분할표 자료를 설명하는 것은 가능하지만 차원축소의 가능성을 결정하기에는 한계가 있다. 본 연구에서는 오즈비의 신뢰구간을 시각적으로 표현할 수 있는 방법으로 Barrowman과 Myers(2003)가 제안한 Raindrop plot을 이용하여 $2{\times}2{\times}K$ 분할표 자료를 설명할 수 있으며 동시에 차원축소의 가능성을 판단할 수 있는 방법을 제안하고자 한다.

• Earthquakes and Structures
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• 제18권3호
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• pp.285-296
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• 2020

Dams are important structures for management of water supply for irrigation or drinking, flood control, and electricity generation. In seismic regions, the structural safety of concrete gravity dams is important due to the high potential of life and economic loss if they fail. Therefore, the seismic analysis of existing dams in seismically active regions is crucial for predicting responses of dams to ground motions. In this paper, earthquake response of concrete gravity dams is investigated using the finite element (FE) method. The FE model accounts for dam-water-foundation rock interaction by considering compressible water, flexible foundation effects, and absorptive reservoir bottom materials. Several uncertainties regarding structural attributes of the dam and external actions are considered to obtain the fragility curves of the dam-water-foundation rock system. The structural uncertainties are sampled using the Latin Hypercube Sampling method. The Pine Flat Dam in the Central Valley of Fresno County, California, is selected to demonstrate the methodology for several limit states. The fragility curves for base sliding, and excessive deformation limit states are obtained by performing non-linear time history analyses. Tensile cracking including the complex state of stress that occurs in dams was also considered. Normal, Log-Normal and Weibull distribution types are considered as possible fits for fragility curves. It was found that the effect of the minimum principal stress on tensile strength is insignificant. It is also found that the probability of failure of tensile cracking is higher than that for base sliding of the dam. Furthermore, the loss of reservoir control is unlikely for a moderate earthquake.

• Journal of Astronomy and Space Sciences
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• 제14권2호
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• pp.179-193
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• 1997

We use B band CCD images to investigate the surface brightness distributions and dynamical properties of 29 Galactic globular clusters. Model fits suggest that 22 clusters show King type surface brightness profiles, while 7 clusters are characterized by power law cusp profiles. For the King type clusters, concentration parameters $(c=log(r_{t}/r_{c}))$ range from 1.20 to 2.10, and core radii are 0.4 to 1.9 pc. The mean value of power law slopes of 7 cuspy clusters was estimated as ${alpha}=1.011{\pm}0.065$. Total masses of King type globular clusters are in the range of $1.7{ imes}10^4M_{odot}$ to $1.0{\times}106M_{\odot}$ with a mean of $1.7{\times}10^5M_{\odot}$. A significant positive correlation between mass and mass-to-light ratio of King type globular clusters has been confirmed with a Pearson's correlation coefficient r = 0.52 and a confidence level of 99%. Our data also confirm a linear relation between total mass and absolute magnitude of King type globular clusters.

• 농촌계획
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• 제20권4호
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• pp.221-232
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• 2014

초고령화된 한국 농촌에서 다양한 교육 및 직업 배경을 가진 중장년층 귀농인구의 유입은 고령화 문제에 대한 대안의 하나로 부각되고 있다. 본 연구는 농가 고령화에 대한 귀농인구의 잠재적인 기여도 측면에서 귀농인구의 지역별 유입 유출 패턴을 분석하였다. 분석에는 로그선형모형과 총합레퍼런스코딩을 사용하였고, 분석자료는 통계청의 2013년 귀농 통계이다. 분석결과에 의하면, 귀농인의 절반 정도가 수도권에서 비수도권 지역으로 이주한 인구이고, 이들을 제외하면 귀농인의 대부분은 원 거주지가 있던 도 내에서 이동하고 있다. 귀농인의 귀농 전 대비 귀농 후 지역 내 오즈비(odds ratio)는 지역별로 차이가 있으며, 귀농인의 성별과 연령에 따라서도 지역별 유입 유출패턴이 다르다. 이는 귀농인 유입의 긍정적 효과를 높이기 위해서는 지자체별 차이를 반영한 특화된 정책이 필요하다는 것을 의미한다.

• 응용통계연구
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• 제6권2호
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• pp.383-391
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• 1993

암치료에 있어서 암세포의 약제 내성 극복에 관한 연구는 새로운 항암제의 개발 못지 않게 중요한 과제이다. 다약제 내성을 극복하기 위하여서는 여러 가지 변조물질(modulators)이 항암제와 결합투여되고 있지만, 아직까지 이들 변조물질중 어느 것이 다약제 내성의 극복에 더 효과적인지는 밝혀지지 않고 있다. 본 논문에서는 인체 암세포주를 대상으로 여러 종류의 항암제에다 변조물질들을 결합투여하는 경우 용량-반응곡선으로부터 상승효과를 검정할 수 있게 통계기법을 소개하고, 또한 일반화 선형모형의 계산 프로그램인 글림 패키지(GLIM Package)의 매크로(macro)를 사용하여 실제 실험자료를 분석한다. 이러한 분석결과는 in-vivo 실험을 통한 실제 임상적용의 근거를 제공하리라 믿어진다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.45-45
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• 2017

On-site monitoring of vegetable growth parameters, such as leaf length, leaf area, and fresh weight, in an agricultural field can provide useful information for farmers to establish farm management strategies suitable for optimum production of vegetables. Unmanned Aerial Vehicles (UAVs) are currently gaining a growing interest for agricultural applications. This study reports on validation testing of previously developed vegetable growth estimation models based on UAV-based RGB images for white radish and Chinese cabbage. Specific objective was to investigate the potential of the UAV-based RGB camera system for effectively quantifying temporal and spatial variability in the growth status of white radish and Chinese cabbage in a field. RGB images were acquired based on an automated flight mission with a multi-rotor UAV equipped with a low-cost RGB camera while automatically tracking on a predefined path. The acquired images were initially geo-located based on the log data of flight information saved into the UAV, and then mosaicked using a commerical image processing software. Otsu threshold-based crop coverage and DSM-based crop height were used as two predictor variables of the previously developed multiple linear regression models to estimate growth parameters of vegetables. The predictive capabilities of the UAV sensing system for estimating the growth parameters of the two vegetables were evaluated quantitatively by comparing to ground truth data. There were highly linear relationships between the actual and estimated leaf lengths, widths, and fresh weights, showing coefficients of determination up to 0.7. However, there were differences in slope between the ground truth and estimated values lower than 0.5, thereby requiring the use of a site-specific normalization method.