• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.7 s.262
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• pp.644-652
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• 2007

In this paper, a technique of simultaneously measuring the velocity and the temperature in micro-scale flow is proposed. This method uses particle tracking velocimetry (PTV) for measuring the velocity and laser induced fluorescence (LIE) for measuring the temperature. To measure the accurate velocity and temperature, images for PTV and for LIE are separated by using two light sources and a shutter which is synchronized with a camera. By using only one camera, measurement system can be simplified and the error from complicate optical system can be minimized. Error analyses regarding the concentrations of fluorescent dye and particle and the light source fluctuation are also conducted. It is found that the error of the temperature and the velocity highly depends on the concentration of fluorescent particles which are used for PTV. This technique is applied to the simultaneous measurement of the velocity and the temperature in the electrokinetic flow. It is found that the velocity and temperature vary with the electric field strength and the concentration of electrolyte.

• ETRI Journal
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• v.39 no.2
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• pp.292-299
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• 2017

We propose pulse-mode dynamic $R_on$ measurement as a method for analyzing the effect of stress on large-scale high-power AlGaN/GaN HFETs. The measurements were carried out under the soft-switching condition (zero-voltage switching) and aimed to minimize the self-heating problem that exists with the conventional hard-switching measurement. The dynamic $R_on$ of the fabricated AlGaN/GaN MIS-HFETs was measured under different stabilization time conditions. To do so, the drain-gate bias is set to zero after applying the off-state stress. As the stabilization time increased from $ 0.1{\mu}s$ to 100 ms, the dynamic $R_on$ decreased from $160\Omega$ to $2\Omega$. This method will be useful in developing high-performance GaN power FETs suitable for use in high-efficiency converter/inverter topology design.

• Wind and Structures
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• v.14 no.3
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• pp.253-283
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• 2011

This paper presents the field measurement results of wind effects on a super-tall building (CITIC Plaza, 391 m high) located in Guangzhou. The field data such as wind speed, wind direction and acceleration responses were simultaneously and continuously recorded from the tall building by a wind and vibration monitoring system during two typhoons. The typhoon-generated wind characteristics including turbulence intensity, gust factor, peak factor, turbulence integral length scale and power spectral density of fluctuating wind speed were presented and discussed. The dynamic characteristics of the tall building were determined based on the field measurements and compared with those calculated from a 3D finite element model of the building. The measured natural frequencies of the two fundamental sway modes of the building were found to be larger than those calculated. The damping ratios of the building were evaluated by the random decrement technique, which demonstrated amplitude-dependent characteristics. The field measured acceleration responses were compared with wind tunnel test results, which were found to be consistent with the model test data. Finally, the serviceability performance of the super-tall building was assessed based on the field measurement results.

• Earthquakes and Structures
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• v.18 no.2
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• pp.163-170
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• 2020

Floor acceleration plays a major role in the seismic design of nonstructural components and equipment supported by structures. Large floor acceleration may cause structural damage to or even collapse of buildings. For precision instruments in high-tech factories, even small floor accelerations can cause considerable damage in this study. Six P-wave parameters, namely the peak measurement of acceleration, peak measurement of velocity, peak measurement of displacement, effective predominant period, integral of squared velocity, and cumulative absolute velocity, were estimated from the first 3 s of a vertical ground acceleration time history. Subsequently, a new predictive algorithm was developed, which utilizes the aforementioned parameters with the floor height and fundamental period of the structure as the new inputs of a support vector regression model. Representative earthquakes, which were recorded by the Structure Strong Earthquake Monitoring System of the Central Weather Bureau in Taiwan from 1992 to 2016, were used to construct the support vector regression model for predicting the peak floor acceleration (PFA) of each floor. The results indicated that the accuracy of the predicted PFA, which was defined as a PFA within a one-level difference from the measured PFA on Taiwan's seismic intensity scale, was 96.96%. The proposed system can be integrated into the existing earthquake early warning system to provide complete protection to life and the economy.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.210.2-210.2
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• 2012

Using Fresnel reflection and Hapke BRDF model with Apollo 10084 soil sample's scattering properties, we constructed a real scale optical lunar model and used it to simulate lunar apparent albedo and moonshine. For Fresnel reflection, the refractive index of $1.68{\pm}0.5$ was used. For Hapke BRDF parameters from BUGs BRDF measurement, the single scattering with w=0.33, hot spot width h=0.017, average phase angle ${\zeta}$=-0.086 and Legendre polynomial coefficients b=0.308, c=0.425 in wavelength 700nm with two types of Henyey-Greenstein phase function was applied. The computation model includes the Sun as a Lambertian scattering sphere, emitting 1.5078 W/m2 at 700nm in wavelength. The Sun and Moon models were then imported into the IRT based radiative transfer computation. The trial simulation of the irradiance levels of moonshine lights shows that they agree well with the ROLO measurement data. We then estimate the lunar apparent albedo to 0.11. The results are to be compared with the measurement data.

• The Journal of Korean Physical Therapy
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• v.30 no.4
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• pp.146-150
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• 2018

Purpose: This study aimed to investigate the effect of active vibration exercise on trunk muscle activity, balance, and activities of daily living in patients with chronic stroke. Methods: Twenty-four patients with chronic stroke were randomly assigned to an experimental (n=12) or a control (n=12) group. The experimental group performed an active vibration exercise workout for 20 minutes a day five times a week for 4 weeks using a flexi-bar. Trunk muscle activity was measured using surface electromyography. Balance was measured using the Berg balance scale. Activities of daily living were measured using the functional independence measure. Results: The intragroup comparison showed significant differences in the rectus abdominis, internal oblique, and external oblique muscle activity values, Berg balance scale score, and functional independence measurement values in the experimental group. The intergroup comparison showed that differences in the rectus abdominis and internal oblique external oblique muscle values, Berg balance scale score, and functional independence measurement value for the experimental group were significantly related to those in the control group. Conclusion: Based on these results, this study proved that the active vibration exercise effectively improved trunk muscle activity, balance, and activities of daily living in patients with chronic stroke.

• The Journal of Korean Academic Society of Nursing Education
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• v.12 no.1
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• pp.52-59
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• 2006

Purpose: The study was attempted to provide basic materials for development of nursing-intervention programs by examining effects of growth hormone therapy on the quality of life, depression and self-esteem. Method: A survey was conducted for 31 adult outpatients as experimental group who have received growth hormone therapy more than 6 months and for 29 adults as control group who have not. A scale developed by Hilditch was used to measure their quality of life and also, the Zung's Self-rating Depression Scale and the Rosenberg's Self-esteem Scale were adopted to measure their depression and self-esteem each. Data were analyzed using one-way and two-way ANOVA Result: 1) there were differences between the two groups in the overall measurement of the quality of life. the growth hormone therapy group was higher in sub-factors 2) There were clear-cut differences between the two groups in depression, so that the control group marked higher score in the measurement of depression. 3) Self-esteem was not identical across the two groups, so that it was more higher for the growth hormone treatment group. Conclusion: Those findings suggest that development of education programs related to growth hormone and nursing-intervention is promising.

• Journal of Families and Better Life
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• v.28 no.4
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• pp.67-76
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• 2010

This study investigates working parent stress. This study surveyed 240 working mothers who are raising toddlers and 106 teachers in Seoul, Cyeong-gi, and Incheon. For this study, the Parenting Stress scale developed by Kim & Kang (1997) was used as the instruments for measurement and parental stress. To measure maternal separation anxiety, this study used the Maternal Separation Anxiety Scale (MSAS) developed by Hock (1989), while the Attitude for Occupation scale developed by Farel (1980) was used to measure the attitude for occupation. In addition, the Preschool Adjustment Questionnaire (PAQ) developed by Jewsuwan, Luster and Kostelink (1992), and modified by Oh Chong Eun (2001) were used as the instruments for measurement and adjustment. Data analysis was done using the SPSS WIN 15.0 version and the collected data were subject to a descriptive statistical analysis, one-way ANOVA t-test, and multiple regression analysis. The influential independent variables affecting parenting stress listed in order of significance were maternal attitude for occupation, adjustment of children, maternal anxiety, and income.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.2
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• pp.35-48
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• 2017

As the technology convergence paradigm emerges, the need for "CIA techniques" to analyze the mutual effects of technology is increasing. However, since the CIA input parameter estimation is difficult, the present study suggests a "CIA input parameter setting model" to alleviate the difficulty of CIA input parameter estimation. This paper is focused on the difference of measurement difficulty by each scale which expert's estimation behavior was defined as measurement activity quantifying the judgment of future technology. Therefore, this model is designed to estimate the input variable as a sequence or isometric scale that is relatively easy to measure, and then converts it into a probability value. The input parameter setting model of the CIA technique consists of three sub-models : 'probability value derivation model', 'influence estimation model', and 'impact value calculation model', in order to develop a series of models the Thurstone V model, Regression Analysis, etc has been used.

• Journal of Korean Academy of Rural Health Nursing
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• v.15 no.1
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• pp.1-8
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• 2020

Purpose: This purpose of this study was to develop a disaster and safety practice measurement tool for elderly people in rural areas. Methods: The tool for this study was developed and validated according to DeVellis' scale development process. The construct validity of the instrument was analyzed by major analysis of Varimax rotation, and the internal inertia was verified by Cronbach's ⍺. Results: The final scale was a 4-point scale, consisting of 23 items in 7 domains. The total explanation was 54.1% and the Cronbach's ⍺ was .80. Conclusion: The results of this study should be useful to assess elders' perception of the importance of safety management for elders.