• Nutrition Research and Practice
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• 제7권4호
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• pp.326-329
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• 2013

Height and weight are important indicators to calculate Body Mass Index (BMI); measuring height and weight directly is the most exact method to get this information. However, it is ineffective in terms of cost and time on large population samples. The aim of our study was to investigate the validity of self-reported height and weight data compared to our measured data in Korean children to predict obese status. Four hundred twenty-two fifth-grade (mean age $10.5{\pm}0.5$ years) children who had self-reported and measured height and weight data were final subjects for this study. Overweight/obese was defined as a BMI of or above the 85th percentile of the gender-specific BMI for age in the 2007 Korean National Growth Charts or a BMI of 25 or higher (underweight : < 5th, normal : ${\geq}5th$ to < 85th, overweight : ${\geq}85th$ to < 95th). The differences between self-reported and measured data were tested using paired t-test. Differences based on overweight/obese status were tested using analysis of variance (ANOVA) and linear trends. Pearson's correlation and Cohen's kappa were tested to examine agreements between the self-reported and measured data. Although measured and self-reported height, weight and BMI were significantly different and children tended to overreport their height and underreport their weight, the correlation between the two methods of height, weight and BMI were high (r = 0.956, 0.969, 0.932, respectively; all P < 0.001), and both genders reported their overweight/non-overweight status accurately (Cohen's kappa = 0.792, P < 0.001). Although there were differences between the self-reported and our measured methods, the self-reported weight and height was valid enough to classify overweight/obesity status correctly, especially in non-overweight/obese children. Due to bigger underestimation of weight and overestimation of height in obese children, however, we need to be aware that the self-reported anthropometric data were less accurate in overweight/obese children than in non-overweight/obese children.

• 정보보호학회논문지
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• 제32권6호
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• pp.1045-1057
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• 2022

최근 양자 내성 암호 표준화 사업을 진행 중인 미국의 국립표준기술연구소는 표준화가 확정된 4개의 알고리즘을 발표하였다. 본 논문에서는 PKE/KEM 분야에서 표준화가 확정된 CRYSTALS-KYBER 알고리즘의 복호화 과정 중 비프로파일링 기반 전력 분석 공격인 CPA(Correlation Power Analysis)와 DDLA(Differential Deep Learning Analysis)에 의해 개인 키가 노출될 수 있음을 보이고자 한다. 실험 결과 개인 키의 일차 다항식 계수복구에 성공하였으며, 특히 DDLA에서는 중간 값의 해밍 웨이트(Hamming Weight)를 라벨로 사용하는 모델에서 평가 기법인 NMM(Normalized Maximum Margin)의 값이 13.0으로 가장 높은 값을 가져 개인 키를 복구할 수 있는 것을 확인하였다. 또한, 복호화 과정 중 암호문을 랜덤하게 분할하고 계수별 곱셈 연산의 시작 지점을 랜덤화하는 방어 기법을 적용하면 상기한 공격을 방어하는 것을 확인하였다.

• 한국농공학회논문집
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• 제65권4호
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• pp.1-10
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• 2023

As a result of climate change, non-point source pollution (NPS) from farmland with the steep slope during the rainy season is expected to have a significant impact on the water system. This study aimed to evaluate the effect of furrow mulching using alfalfa and PAM (Polyacrylamide) materials for each rainfall event, while considering the load characteristics of NPS. The study was conducted in Wanju-gun, Jeollabuk-do, in 2022, with a testbed that had a slope of 13%, sandy loam soil, and maize crops. The testbed was composed of four plots: bare soil (Bare), No mulching (Cont.), Vegetation mulching (VM), and PAM mulching (PM). Runoff was collected from each rainfall event using a 1/40 sampler and the NPS load was calculated by measuring the concentrations of SS, T-N, T-P, and TOC. During farming season, the reduction efficiency of NPS load was 37.1~59.5% for VM and 38.2~75.7% for PM. The analysis found that VM had a linear regression correlation (R²=0.28~0.86, P-value=0.01~0.1) with elapsed time of application, while PM had a quadratic regression correlation (R²=0.35~0.80, P-value=0.1). These results suggest that the selection of furrow mulch materials and the appropriate application method play a crucial role in reducing non-point pollution in farmland. Therefore, further studies on the time-series reduction effect based on the application method are recommended to develop more effective preemptive reduction technologies.

• Journal of Animal Science and Technology
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• 제44권4호
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• pp.383-390
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• 2002

1998년도부터 2001년도까지 실시한 한우 후대검정에서 공시된 후보종모우들에 대한 근친도를 조사해 본 결과, 대부분의 종모우들은 근친되지 않고 있어 한우 종모우 집단은 아직 non-inbred 집단으로 간주해도 무방할 것으로 사료되었다. 하지만 많은 개체들간에 혈연관계가 있는 것으로 조사되어 앞으로 근친도가 크게 상향될 것으로 예상되기 때문에 농가에서 보다 계획적인 정액 선택을 통한 교배가 권장된다. 또한 거세 검정우 1262두로부터 조사된 도체성적들에 대한 유전모수를 선형모형하에서 REML 방법으로 추정된 결과와 근내지방도를 범주형자료로 간주하여 Gibbs sampling 방법으로 추정한 결과, 기존의 비거세우를 대상으로 추정한 결과 보다 다소 높게 추정되었으며 GS방법에 의한 추정치가 REML 방법에 의한 추정치보다 높게 추정되었다. 특히 근내지방도에 대한 유전력 추정치는 GS방법에서 0.74으로 아주 고도의 유전력을 갖는 것으로 추정되어 근내지방도에 대한 개량의 용이함을 제시하였다. 또한 근내지방도와 등지방두께 간에는 0.46의 유전상관을 갖는 것으로 추정되었으며 근내지방도와 출하시 체중간에는 -0.44의 부의상관을 갖는 것으로 추정되었다. 반면에 도체율과 근내지방도간에는 -0.72의 강한 부의상관을 갖는 것으로 추정되었는데 도체율에 대한 변이가 상당히 낮은 변이계수를 고려할 때 추정치에 대한 신뢰도가 낮을 것으로 예상되었다. 종모우의 육종가에 대한 추정방법간의 상관은 다소 낮을 것으로 예상되기 때문에 이에 대한 연구가 필요할 것으로 사료된다.

• 사물인터넷융복합논문지
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• 제9권6호
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• pp.63-73
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• 2023

본 연구는 비대면 학습환경에서 온라인 강의수강을 경험한 일 간호대학 재학생을 대상으로 학습몰입, 학습만족도, 학업적 자기효능감, 학업성취도 및 학업스트레스 정도를 확인하고 변수간의 상관관계 및 학업스트레스에 영향을 미치는 요인을 규명하고자 한다. 본 연구에서는 서울시에 위치한 일 간호대학의 재학생 143명을 대상으로 구글온라인 설문지를 통해 2023년 9월 1일부터 2023년 9월 25일까지 자료수집을 시행하였고, SPSS Statistics 25.0을 활용하여 기술통계, t-검정, 일원분산분석, 피어슨상관계수, linear multiple regesion을 시행하였다. 일반적 특성에 따른 차이 분석 결과 학업스트레스는 간호학과 지원동기(F=4.465, p=.005)와 전공만족도(F=36.499, p=.000)에 따라 유의한 차이가 나타났으며 학업스트레스는 학습몰입(r=-.464, p<.010), 학업적 자기효능감(r=-.522, p<.010), 학업성취도(r=-.379, p<.010)간에 유의미한 부적(-) 상관관계가 있는 것으로 나타났으나 학습만족도는 학업스트레스와 상관관계가 없는 것으로 나타났다. 학업스트레스에 영향을 미치는 변인은 전공만족도(𝛽=.367, p<.01), 학습몰입(𝛽=-.186, p<.05), 학업적 자기효능감(𝛽=-.241, p<.05)으로 확인되었으며 학업스트레스에 대한 설명력은 40%였다. 본 연구결과는 간호대학생의 학업스트레스 완화를 위한 중재 프로그램의 기초자료로 활용할 수 있을 것이다.

• Wind and Structures
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• 제13권6호
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• pp.529-556
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• 2010

This paper investigates the correlation of wind characteristics monitored on a cable-stayed bridge. Total five anemoscopes are implemented into the bridge. Two out of 5 anemoscopes in inflow and two out of 5 anemoscopes in wake-flow along the longitudinal direction of the bridge are installed. Four anemoscopes are respectively distributed at two cross-sections. Another anemoscope is installed at the top of the tower. The correlation of mean wind speed and direction, power spectral density, the turbulent intensity and integral length of wind in flow at two cross-sections are investigated. In addition, considering the non-stationary characteristics of wind, the spatial correlation in time-frequency is analyzed using wavelet transform and different phenomenon from those obtained through FFT is observed. The time-frequency analysis further indicates that intermittence, coherence structures and self-similar structures are distinctly observed from fluctuant wind. The flow characteristics around the bridge deck at two positions are also investigated using the field measurement. The results indicate that the mean wind speed decrease when the flow passing through the deck, but the turbulence intensity become much larger and the turbulence integral lengths become much smaller compared with those of inflow. The relationship of RMS (root mean square) of wake-flow and the mean wind speed of inflow is approximately linear. The special structures of wake-flow in time-frequency domain are also analyzed using wavelet transform, which aids to reveal the forming process of wake-flow.

• Journal of the Korean Wood Science and Technology
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• 제44권1호
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• pp.1-8
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• 2016

목재 데크재에 인위적인 결함인 구멍을 부여하고 이들의 성능평가를 위해 초음파 비파괴 시험법을 적용하였다. 구멍의 크기와 개수를 달리하여 각각에 대한 초음파 전달속도를 측정하고 탄성계수를 산정하여 그 영향을 비교분석하였다. 시험결과 구멍의 크기가 커짐에 따라 초음파 전달속도와 탄성계수는 감소하였으며 이들 상호간에는 직선상관관계를 보였다. 구멍의 크기가 증가하면 초음파의 전달 길이는 증가하며 이에 따라 초음파속도는 감소하였지만 구멍의 크기가 15 mm 이하로 작은 경우에는 구멍이 없는 부재에 비해 그 차이가 작게 나타났다. 구멍의 개수가 많아짐에 따라 초음파 전달속도와 탄성계수는 감소하였으며 이들 상호간에는 높은 직선상관관계를 보였다. 구멍의 개수가 3개인 경우 초음파속도는 약 3.5% 정도 감소한데 비하여 탄성계수는 27% 정도로 현저히 감소하여 더 큰 감소경향을 나타내었다. 이들의 결과로부터 구멍의 크기와 개수는 초음파 전달속도와 탄성계수에 영향을 미치며 구멍의 크기가 크고 개수가 많아질수록 그 영향은 더욱 커질 것으로 여겨진다. 또한 작은 결함의 탐지를 위해서는 초음파 전달속도에만 의지할 것이 아니라 여러 초음파 변수를 고려하여 적용하는 방법을 고려하여야 할 것으로 생각된다.

• 경영과학
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• 제18권1호
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• pp.135-145
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• 2001

In recent environment of dynamic management, there is growing recognition that information and knowledge management systems are essential for efficient/effective decision making by CEO. To cope with this situation, we suggest the Data-Miming scheme as a key component of integrated information and knowledge management system. The proposed system measures business performance by considering both VA(Value-Added), which represents stakeholder’s point of view and EVA (Economic Value-Added), which represents shareholder’s point of view. To mine the new information & Knowledge discovery, we applied the improved genetic algorithms that consider predictability, understandability (lucidity) and reasonability factors simultaneously, we use a linear combination model for GAs learning structure. Although this model’s predictability will be more decreased than non-linear model, this model can increase the knowledge’s understandability that is meaning of induced values. Moreover, we introduce a random variable scheme based on normal distribution for initial chromosomes in GAs, so we can expect to increase the knowledge’s reasonability that is degree of expert’s acceptability. the random variable scheme based on normal distribution uses statistical correlation/determination coefficient that is calculated with training data. To demonstrate the performance of the system, we conducted a case study using financial data of Korean automobile industry over 16 years from 1981 to 1996, which is taken from database of KISFAS (Korea Investors Services Financial Analysis System).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.481-481
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• 2000

We investigated the structure-activity relationships on use of multi-layer neural networks. The relationships are techniques required in developments of medicines. Since many kinds of observations might be adopted on the techniques, we discussed some points between the observations and the properties of multi-layer neural networks. In the structure-activity relationships, an important property is not that standard deviations are nearly equal to zero for observed physiological activity, but prediction ability for unknown medicines. Since we adopted non-linear approximation, the function to represent the activity can be defined by observations; therefore, we believe that the standard deviations have not significance. The function was examined by "leave-one-out" method, which was originally introduced for the multi-regression analysis. In the linear approximation, the examination is significance, however, we believe that the method is inappropriate in case of nonlinear fitting as neural networks; therefore, we derived a new index fer the relationships from the differential of information propagation in the neural network. By using the index, we discussed physiological activity of an anti-cancer medicine, Mitomycine derivatives. The neuro-computing suggests that there is no direction to extend the anti-cancer activity of Mitomycine, which is close to the trend of anticancer developing.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.22-25
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• 2008

The dynamic response of the head arm assembly (HAA) of a hard disk drive to an impact load was obtained from a 3D non-linear finite element model using ANSYS/LS-DYNA and from experiments using a modified levitation mass method (LMM). In the finite element model, the impact load was created by modeling the mass as a rigid body and making it collide with the HAA. The velocity, displacement, acceleration, and inertial force of the mass were then obtained from the time history data of the finite element analysis. In the LMM, a mass that was levitated with an aerostatic linear bearing, and hence encountered negligible friction, was made to collide with the actuator arm, resulting in a dynamic bending test for the arm. During the collision, the Doppler frequency shift of the laser beam reflected from the mass was accurately measured with an optical interferometer. The velocity, displacement, acceleration, and inertial force of the mass were accurately calculated from the measured time-varying Doppler frequency shift. A good correlation between the experimental data and FEA results was observed. The FEA was also used to investigate the dynamic response of the HAA to impact by different masses.