• Research in Community and Public Health Nursing
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• v.31 no.1
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• pp.96-106
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• 2020

Purpose: This study aimed to examine the level of acculturative stress, career stress, social support and depression, and identify factors affecting depression among Korean international students in China. Methods: Data were collected from 157 Korean students studying in undergraduate, graduate, students exchange programs and language training courses in G university, J university, and S university in G city, Guangdong Province, China, from September 1 to October 27, 2017. The data were analyzed with descriptive statistics, t-test, ANOVA, and multiple linear regression. Results: The mean acculturative stress was 62.24±18.08 out of 165, whereas the mean career stress was 65.47±19.79 out of 125. The mean social support was 95.03±14.64 out of 125, and the mean depression score was 13.83±9.24 out of 60. The factor that had the greatest effect on depression among the participants was acculturative stress (β=.26, p=.001), followed by career stress (β=.24, p=.002), frequency of weekly phone calls with family (β=.19, p=.006), source of tuition payment (β=.18, p=.009), and self-perceived health (β=.15, p=.040). The model explained 33% of the variance. Conclusion: It is necessary to develop depression prevention and management programs as well as a customized health promotion program that account for the factors identified to have an effect on depression, namely, acculturative stress, career stress, frequency of weekly phone calls with family, source of tuition payment, and self-perceived health, and increase awareness of depression among international students.

• Journal of the Korean GEO-environmental Society
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• v.17 no.2
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• pp.13-22
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• 2016

Accurate settlement estimation of dredged soft soil deposits is significantly important to prevent potential disasters during land reclamation. An application of the non-linear finite strain consolidation theory is inevitable in dealing with a very soft ground formation such as dredged fill. In this paper, a series of the sedimentation-consolidation test, self-weight consolidation test and CRS test were conducted to clarify sedimentation and consolidation characteristics of dredged fill in the Songdo area, Incheon. In addition, the settlement of dredged fill was numerically simulated using the PSDDF program. The dredged soil obtained from the Songdo area was classified as low-compressible silt (ML) based on USCS (Unified Soil Classification System), and the final bulking factors were estimated to be 1.56 and 1.17 by Yano's method and the numerical simulation, respectively. This difference is attributable to relatively high reclaimed height and large permeability of dredged soil in this region.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.43.2-43.2
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• 2015

The RGB Bayer filter system consists of a mosaic of R, G, and B filters on the grid of the photo sensors which typical commercial DSLR (Digital Single Lens Reflex) cameras and CCD cameras are equipped with. Lot of unique astronomical data obtained using an RGB Bayer filter system are available, including transient objects, e.g. supernovae, variable stars, and solar system bodies. The utilization of such data in scientific research requires that reliable photometric transformation methods are available between the systems. In this work, we develop a series of equations to convert the observed magnitudes in the RGB Bayer filter system (RB, GB, and BB) into the Johnson-Cousins BVR filter system (BJ, VJ, and RC). The new transformation equations derive the calculated magnitudes in the Johnson-Cousins filters (BJcal, VJcal, and RCcal) as functions of RGB magnitudes and colors. The mean differences between the transformed magnitudes and original magnitudes, i.e. the residuals, are (BJ - BJcal) = 0.064 mag, (VJ - VJcal) = 0.041 mag, and (RC - RCcal) = 0.039 mag. The calculated Johnson-Cousins magnitudes from the transformation equations show a good linear correlation with the observed Johnson-Cousins magnitudes.

• Korean Journal of Community Nutrition
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• v.25 no.1
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• pp.61-70
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• 2020

Objectives: This study examined the association of the total diet quality with the incidence risk of metabolic syndrome constituents and metabolic syndrome among Korean adults. Methods: Based on a community-based cohort of the Korean Genome and Epidemiology Study (KoGES) from 2001 to 2014, data from a total of 5,549 subjects (2,805 men & 2,744 women) aged 40~69 years at the baseline with a total follow-up period of 38,166 person-years were analyzed. The criteria of the National Cholesterol Education Program Adult Treatment Panel was employed to define metabolic syndrome. The total diet quality was estimated using the Korean Healthy Eating Index (KHEI). Hazard ratios (HR) and 95% confidence intervals (CI) for risk of metabolic syndrome constituents and metabolic syndrome in relation to KHEI quintile groups was calculated by multivariate Cox proportional hazards regression model. Results: After adjusting for age, energy intake, income, education, physical activity, smoking, and drinking, the incidence of abdominal obesity and high blood pressure was significantly lower, by approximately 29.7% (P < 0.01) and 25.2% (P < 0.01), respectively, in the fifth KHEI quintile compared to the first quintile in men. A significant decreasing trend of the metabolic syndrome incidence was observed across the improving levels of KHEI (HRq5vs.q1: 0.775, 95% CIq5vs.q1: 0.619~0.971, P for trend < 0.01). In women, the incidence of abdominal obesity and metabolic syndrome was significantly lower, by approximately 29.8% (P < 0.01) and 22.5% (P < 0.05), respectively, in the fifth KHEI quintile compared to the first quintile adjusting for multiple covariates. On the other hand, the linear trend of metabolic syndrome risk across the KHEI levels did not reach the significance level. Conclusions: A better diet quality can prevent future metabolic syndrome and its certain risk factors among Korean men and women.

• The Journal of Engineering Geology
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• v.2 no.2
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• pp.113-130
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• 1992

Groundwater in crystalline basement is controlled primarily by tectonic fractures. It is evident that the delineation of the heavily faulted area and/or fractures deeply developped should be considerable value in deep-seated low enthalphy geothermal water. Electrical and electromagnetic methods have effectively been employed to map hydraulic faults and shear zones for groundwater exploration. In this study VLi; dipoledipole resistivity, controlled source audio~frequency magneto-telluric(CSAMT) and magnetic methods were applied in the Bomun resort area, adjacent to Kyongju city, southeastern part of Korea. The integrated geophysical tools employed in this experiment can be manifested themselves as: 1. Magnetic high for granite intrusions which is more favorable for geothermal gradient increase in depth. 2. VLF cross-over trends for mapping linear shallow conductive fractures and shear zones. 3. Dipole-dipole resistivity distributions for the deep-seated(less than 500m in depth) fractures and shear zones. The dipole-dipole resistivity field data were inverted to the true resistivity distribution with two-dimensional automatic inversion program based on the finite-difference method. 4. CSAMT provides an efficient way of delineating fractures and fault zones if the depth is greater than about 500m.

• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.83-92
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• 2017

Increased investment in environment-friendly transport vehicles has led to rapid transit of railway tracks, double track program, linear improvements in railway lines, and moving railroad routes into the suburbs. They resulted in fast increase of railway yards. However, as the railroad yards being neglected, urban fine sites have been degraded. Local governments kept seeking ways to utilize the railway yards. In addition, Ministry of land, infrastructure and transport enacted "Guidelines for utilization of railway yards". The Guidelines categorized the railway yards into three types; conservation, utilized, and other sites in order to make efficient use of them. The railway yards have been converted and used for parks, rail bike trails, bike paths, and solar projects. It seems that studies are needed on diverse use of the yards and on post evaluation. This study investigated current uses of railway yards, domestic and foreign, and analyzed for the pertinent conditions on natural and cultural landscape, educational value, location and accessibility, potential for recreational area, and development opportunities. In this study, I proposed a quantitative evaluation method, and to find way to diversify the use of railway yards.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.467-475
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• 2011

Aerial spraying technology using a small unmanned helicopter is an efficient and practical tool to achieve stable agricultural production to improve the working condition. An attitude controller for the agricultural helicopter would be helpful to aerial application operator. In order to construct the flight controller, a state space model of the helicopter should be identified using a dynamic analysis program, such as CIFER$^{(R)}$. To obtain the state space a model of the helicopter, frequency-sweep flight tests were performed and time history data were acquired using a custom-built stick position transmitter. Four elements of stick commands were accessed for the collective pitch (heave), aileron (roll), elevator (pitch), rudder (yaw) maneuvers. The test results showed that rudder stick position signal was highly linear with rudder input channel signal of the receiver; however, collective pitch stick position signal was exponentially manipulated for the convenience of control stick handling. The acquired stick position and flight dynamic data during sweep tests would be analyzed in the followed study.

• Biomolecules & Therapeutics
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• v.13 no.2
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• pp.118-122
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• 2005

The objective of the present investigation was to study pharmacokinetics of promethazine in Korean healthy subjects using a validated HPLC method. The HPLC analysis was performed on a Capcell Pak CN column with a mixture of acetonitrile-0.02M potassium dihydrogen phosphate (42:58, v/v, pH 6.0) and the analyte was quantified with UV detection at 251 nm. The calibration curve of the drug was linear over the range of 1-40ng/mL in human serum and the limit of quantification (LOQ) was 1 ng/mL. This analytical method was validated and shown to be specific, accurate, precise and reproducible. This method was applied to pharmacokinetic study of promethazine in Korean healthy volunteers following an oral administration of two 25 mg Himazin tablets (50 mg promethazine ${\cdot}$HCI) after overnight fasting. Serum samples were collected at given intervals over a 36-hour period (12 points) and pharmacokinetic parameters were determined from serum concentration-time profile using WinNonlin program. The estimated $AUC_{0__\infty}$, $AUC_{0_\infty}$, $C_{max}$, $T_{max}$ and $t_{1/2}$ of promethazine obtained from Korean healthy subjects were 103.84 ${\pm}$84.30 ng${\cdot}$hr/mL, 87.94${\pm}$81.02 ng${\cdot}$hr/mL, 13.43${\pm}$10.92 ng/mL, 2.00${\pm}$1.16 hr and 5.88${\pm}$3.47 hr, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.8
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• pp.72-78
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• 2009

We developed a line standards measurement system using an optical microscope and measured two kinds of line standards. It consists of three main parts: an optical microscope module including a CCD camera, a stage system with a linear encoder, and a measurement program for a microscopic image processing. The magnification of microscope part was calibrated using one-dimensional gratings and the angular motion of stage was measured to estimate the Abbe error. The threshold level in line width measurement was determined by comparing with certified values of a line width reference specimen, and its validity was proved through the measurement of another line width specimen. The expanded uncertainty (k=2) was about 100 nm in the measurements of $1{\mu}m{\sim}10{\mu}m$ line width. In the comparison results of line spacing measurement, two kinds of values were coincide within the expanded uncertainty, which were obtained by the one-dimensional measuring machine in KRISS and the line standards measurement system. The expanded uncertainty (k=2) in the line spacing measurement was estimated as $\sqrt{(0.098{\mu}m)^2+(1.8{\times}10^{-4}{\times}L)^2}$. Therefore, it will be applied effectively to the calibration of line standards, such as line width and line spacing, with the expanded uncertainty of several hundreds nanometer.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.961-971
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• 2008

In the design of a rotor shaft, care should be taken to minimize vibration by taking into account the sources of vibration. In addition, the intensity critical speed, stability, and other related aspects of the system must be considered. especially when it is operated at a critical speed, it is important to address issues related to vibration, as an increase in the whirling response of the rotor shaft can cause damage to the shaft, destruction of the rotor parts, and detrimental abrasions on the bearings. In this thesis, the vibration characteristics of a rotor shaft are investigated through the use of the finite element method. Variations of the diameters and lengths were used to determine the effect of a rotor shaft using Beam No.188(3D linear strain beam) in ANSYS version 11.0 as a universal interpretation program for finite elements. Special care was taken to prevent excessive vibration, which can result from resonance at the initial stage, in the formulation of a dynamic design for a rotor shaft through calculations while changing the diameters and the lengths of the shaft. Moreover, the dynamic characteristics of the critical speed, total mass, D/L(diameter to length) ratio, and natural frequency were verified. Furthermore, the rotor shaft applied by bearing element was calculated and compared by using Combi No. 214(2-D spring-damper bearing).