• Journal of Environmental Science International
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• v.23 no.4
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• pp.543-552
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• 2014

Fixed Electromagnetic Wave Surface Velocimetry (Fixed EWSV) has been started to be used to measure flood discharge in the mountain stream, since it has various advantages such that it works well to continuously measure stream discharge even in the night time as well as very strong weather. On the contrary, the Fixed EWSV only measures single point surface velocity, thus it does not consider varying feature of the transverse velocity profile in the given stream cross-section. In addition, a conventional value of 0.85 was generally used as the ratio for converting the measured surface velocity into the depth-averaged velocity. These aspects could bring in error for accurately measuring the stream discharge. The capacity of the EWSV for capturing rapid flow velocity was also not properly validated. This study aims at conducting error analysis of using the EWSV by: 1) measuring transverse velocity at multiple points along the cross-section to assess an error driven by the single point measurement; 2) figuring out ratio between surface velocity and the depth-averaged velocity based on the concurrent ADCP measurements; 3) validating the capacity of the EWSV for capturing rapid flow velocity. As results, the velocity measured near the center by the fixed EWSV overestimated about 15% of the cross-sectional mean velocity. The converting ratio from the surface velocity to the depth-averaged velocity was 0.8 rather than 0.85 of a conventional ratio. Finally, the EWSV revealed unstable velocity output when the flow velocity was higher than 2 m/s.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.35-41
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• 2014

The present study has been carried out to reduce the heat loss from a refrigerator by numerical heat transfer analysis and temperature measurement experiment for the verification of heat transfer analysis result. To perform this purpose, two dimensional heat transfer analysis and measurement of temperature on the surface of freezer for the horizontal cross sectional plane of a refrigerator has been accomplished. From the present study, it could be seen that the steel support in the mullion near gasket region has a heat transfer characteristics which transfer outside heat well from the high temperature hotline and outside air to the inner refrigerator. The effect of removing steel support on the reducing heat loss of a refrigerator was 24.8% and removing steel support might introduce significant improvement of refrigerator heat loss.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.92-98
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• 2008

A combination of the instrumented indentation and 3D morphology measurement has been tried in order to perform a real-time property measurement of degraded materials in gas pipelines; three-dimensional indent morphologies were recorded using a reflective laser scanner after a series of insturmented indentations on three metallic specimens. Dimensions of the permanent deformation zone and contact boundary were analyzed from the cross-sectional profile over an remnant indent and used for estimating yield strength and hardness, respectively. Estimated yield strength was comparable with that from uniaxial tensile test and actual hardness implying material pile-up effects was lower than the calculated value from indentation curve by $20{\sim}30%$. It means that this 3D image analysis can explain the material pile-up effects on the contact properties. Additionally, a combined system of indentation and laser sensor was newly designed by modifying a shape of the indentation loading fixture.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.23-27
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• 2019

In this paper, we propose a micro vibro tomography(MVT) method, that can be used to visualize two-dimensional cross-sectional images and micro-vibration tomographic images in real time in a non-contact and non-destructive manner. The proposed method is based on the optical coherence tomography(OCT) technique, with an additionally customized image processing algorithm. The proposed method can detect the micro-motions or vibrations in sample structures by measuring the phase shift variations in the sample structures. In this study, we show the potential capabilities of the proposed MVT system for measuring the micro-vibrations generated when sound waves in a frequency range of 2~5 kHz are applied to an $80-{\mu}m$ thick latex phantom, which mimics the changes in physical structure of the human tympanic membrane while hearing. Additionally, three-dimensional volumetric images of the MVT method were recorded to observe the surface morphological changes in the surface of the phantom sample which mimics the human tympanic membrane while hearing.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.161-166
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• 2021

Objective: The purpose of this study was to quantitatively evaluate the Wii Balance Board (WBB)-based jump performance for the elderly and to confirm the difference in jump performance according to age. Design: Cross-sectional study. Methods: 40 young adults (aged 22.5±2.2 years) and 33 elderly (aged 75.1±5.2 years) without orthopedics disease participated in this study. Standing on the WBB then, with the signal "start," jump vertically to the maximum height at which you can jump, land on the force plate after jump and keep it standing on both feet. All subjects were required to practice the jump sufficiently before starting the measurement, each measuring three times, and the mean values were used. A one-minute break was provided between each trial. Evaluators waited within 1meter for every test to prepare for fall. Results: The vertical ground reaction force of elderly and young adults when jumping using WBB showed a significant difference (p<0.05) and demonstrated discriminant validity. Between two groups, there were significant differences in overall jump time (p<0.05), maximum value (p<0.05), minimum value (p<0.05), center of pressure (COP) pathlength (p<0.05), and flight time p<0.05). Conclusions: This study found that performing the vertical jump, the elderly showed longer jump time, lower vertical ground reaction force, COP pathlength and shorter flight phase than healthy young adults using WBB and demonstrated that as a measurement tool, WBB discriminated vertical jump performance between elderly and young adults.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.488-492
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• 2022

Objective: The purpose of this study is to find out the reliability and validity of the newly updated Balancia 2.5 program using Wii balance board through equipment that can measure center of pressure data with the precision. Design: Cross-sectional study Methods: Twenty-seven healthy adults participated in the study. The subjects were assessed for static balance ability by Accusway, and were assessed for static balance ability on Wii balance board connected to theBalancia 2.5 program.To limit postural fluctuations due to stare, the subjects were asked to look at a 15 cm dot drawn 3 m in front of them for 30 seconds with their eyes open. Static balance ability data such as path length and sway velocity were extracted from all measurement tools.Intra-rater and inter-rater reliability and validity were extracted through intraclass correlation coefficient (ICC) and 95% confidence interval (CI). Results: The intra-rater reliability that the same rater shows consistent results through test-retest was a high level at ICC=0.968 (0.926~0.986), and inter-rater reliability that the requires consistent results even when measured by different raters was a high level at ICC=0.943 (0.870~0.975). The validity was a high level at ICC=0.948 (0.881~0.977), which shows whether the measurement tool is properly measuring what it is intended to measure. Conclusions: The Balancia 2.5 program, newly updated through this study, proved to be a program with high reliability and validity in evaluating static balance ability like the existingBalancia 2.0 program.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.414-420
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• 2022

Objective: In this study, the test-retest reliability and validity were presented to evaluate the usability of isokinetic rehabilitation equipment for the knee joint. Design: Cross-sectional design, reliability & validity study. Methods: Thirty healthy adults participated in the study. A CSMI dynamometer was used as a standardized measuring device to present the validity of the equipment. It was measured based on the dominant leg. The average peak torque value was selected as the measurement variable. After the measurement, a questionnaire was conducted on safety, satisfaction, and performance through the usability evaluation questionnaire. Results: The knee joint isokinetic rehabilitation equipment showed high reliability with Intraclass Correlations Coefficients (ICC) =0.883~0.956. In order to check the validity of the equipment, the 95% confidence interval of the mean difference limit was confirmed by the Bland & Altman plot. As a result, all three angular velocities showed a smaller confidence interval in the flexion than in extension. There were less than 10 plots that were not included in 2 Standard Deviation (SD) between all measurements. As a result of the usability evaluation questionnaire, the average of the safety domain(4.9±0.4), satisfaction domain(4.1±0.8), performance domain(4.3±0.8). Conclusions: If the product is improved by supplementing the items identified in the usability evaluation process, it is judged that it can be used as a useful device in various knee joint rehabilitation fields.

• Korean Medical Education Review
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• v.25 no.3
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• pp.243-257
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• 2023

This study aimed to analyze trends in research on depression among medical students in Korea and to conduct a meta-analysis to determine the average correlation coefficients between depression and related variables. In total, 38 quantitative studies (four theses and 34 journal articles) published between January 1995 and February 2023 were analyzed according to publication year, subjects, analysis methods, and measurement tools. Among them, 15 studies that provided numerical information on the relationships between depression and variables such as self-esteem, social support, grade point average (GPA), stress, and academic stress were selected for meta-analysis. The main findings of this study were as follows. First, quantitative research on depression among medical students began in earnest in 2009, and cross-sectional studies targeting first-year and second-year medical students were the most prevalent. Furthermore, the most commonly used analysis method was difference testing, and the Beck Depression Inventory was the most frequently used measurement tool. Second, the mean correlation coefficients between depression and stress, self-esteem, social support, academic stress, and GPA were 0.534, 0.532, 0.465, 0.390, and 0.102, respectively. The results for self-esteem, stress, and academic stress showed substantial heterogeneity, while those for social support and GPA showed little heterogeneity. These findings suggest that educational interventions, such as social support improvement programs, are necessary to prevent depression among medical students.

• Journal of Distribution Science
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• v.22 no.2
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• pp.71-82
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• 2024

Purpose: Despite significant research on decision-making, researchers struggle to comprehend the decision-making process. This paper aims to not only examine the relationship between problem-solving skills, cognitive competency, and decision-making but also develop measurement instruments for cognitive competency and problem-solving skills to better model decision-making. Research Design, Methodology and Approach: A cross-sectional study was conducted by surveying 292 university students in HCM City, Vietnam, via email sent randomly by Google Forms. This study identifies the conceptual framework and tests the hypotheses using a deductive approach. The SPSS program was used to evaluate the scales' reliability, and the SmartPLS program was used to assess the measurement and structural models. Results: The results show that the research model better modelled the relationship between problem-solving skills, cognitive competency, and decision-making. Although thinking ability has no direct impact on decision-making, both creativity and problem-solving skills have a positive impact on decision-making. The mediating role of problem-solving skills is also determined by the positive relationship between cognitive competency and decision-making. Conclusions: This study highlights decision-making efficiency through the cognitive process from low to high levels and provides for policymakers and managers to explain the decision-making process in a variety of sectors, such as distribution chains, marketing, and human resource distribution.

• Nutrition Research and Practice
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• v.7 no.1
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• pp.43-48
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• 2013

Quantities as well as distributions of adipose tissue (AT) are significantly related to cardiovascular disease (CVD) risk factors and can be altered with caloric restriction. This study investigated which cross-sectional slice location of AT is most strongly correlated with changes in CVD risk factors after caloric restriction in obese Korean women. Thirty-three obese pre-menopausal Korean women ($32.4{\pm}8.5$ yrs, BMI $27.1{\pm}2.3\;kg/m^2$) participated in a 12 weeks caloric restriction program. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were measured using computed tomography (CT) scans at the sites of L2-L3, L3-L4, and L4-L5. Fasting serum levels of glucose, insulin, triglyceride, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), leptin and homeostasis model assessment-insulin resistance (HOMA-IR) were observed. Pearson's partial correlation coefficients were used to assess the relationship between AT measurement sites and changes in CVD risk factors after calorie restriction. When calories were reduced by 350 kcal/day for 12 weeks, body weight (-2.7%), body fat mass (-8.2%), and waist circumference (-5.8%) all decreased (P < 0.05). In addition, following caloric restriction, serum levels of glucose (-4.6%), TC (-6.2%), LDL-C (-5.3%), leptin (-17.6%) and HOMA-IR (-18.2%) decreased significantly (P < 0.05) as well. Changes in VAT at the level of L3-L4 were significantly greater than those at other abdominal sites, and these changes were correlated with changes in TC (P < 0.05), LDL-C (P < 0.001), SBP (P < 0.001) and HOMA-IR (P < 0.01). These results show that VAT at L3-L4 had a stronger correlation with CVD risk factors than with other AT measurement sites after caloric restriction.