• Journal of Korea Water Resources Association
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• v.32 no.1
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• pp.41-47
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• 1999

More than 100 bridges in Korea have been annually collapsed or badly damaged by the scouring around bridge piers, particularly in the flood season. To prevent from such a tragedy, the fundamental study on the bridge scouring is required, which is essential not only to estimate the scour depth with reliability but to take it into consideration in its design. However, it is not easy to find out the physical scour mechanism since many factors on the scour are coupled with. Moreover, there exists none of the measured data sufficiently for the primary research on the bridge scour depths. In this study the field measurements are carried out to provide the fundamental data for the research and the design. Scouring depth, pier width, flow depth, and the approaching velocity and degree of pier nose are measured broadly in small and medium streams. From these measurements the present situation on bridge scours can be understood and some of important factors to affect the stability of bridges are analyzed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1592-1602
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• 1990

Mixed mode surface crack in finite-width plate subjected to uniform tension and bending has been analyzed in 3-D problem by using boundary element method. The calculations were carried out for the surface crack angles(.a/pha.) of 0.deg., 15.deg., 30.deg., 45.deg., 60.deg., and 75.deg., and for the aspect ratio(a/c) of 0.2, 0.4, 0.6 and 1.0 to get stress intensity factors at the boundary points of the surface crack. For the aspect ratio of 1.0 and the surface crack angles, finite element method was used to check the results in this study. Comparison of the results from both methods showed good agreement.

• Earthquakes and Structures
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• v.16 no.5
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• pp.611-623
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• 2019

A set of mid-rise bare and uniformly infilled reinforced-concrete frame buildings are analyzed for two different seismic intensities of ground-motions (i.e., 'Design Basis Earthquake' and 'Maximum Considered Earthquake') to study their floor response. The crucial parameters affecting seismic design force for acceleration-sensitive non-structural components are studied and compared with the guidelines of the European and the United States standards, and also with the recently developed NIST provisions. It is observed that the provisions of both the European and the United States standards do not account for the effects of the period of vibration of the supporting structure and seismic intensity of ground-motions and thereby provides conservative estimates of the in-structure amplification. In case of bare frames, the herein derived component amplification factors for both the design basis earthquake and the maximum considered earthquake exceeds with their recommended values in the European and the United States standards for non-structural components having periods in vicinity of the higher modes of vibration, whereas, in case of infilled frames, component amplification factors exceeds with their recommended value in the European standard for non-structural components having periods in vicinity of the fundamental mode of vibration, and only for the design basis earthquake. As a consequence of these observations, as well as capping on the design force (in case of United states standard and NIST provisions), in case of the design basis earthquake, the combined amplification factor is underestimated for non-structural components having periods in vicinity of the higher modes of vibration of bare frames, and also for non-structural components having periods in vicinity of the fundamental mode of vibration of infilled frames. At the maximum considered earthquake demand, excepting non-structural components having periods in vicinity of the higher modes of vibration of bare frames, all provisions generally provide conservative estimates of the design floor accelerations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.173-180
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• 2020

This is the report of a case study to describe the results of applying an evaluation tool for communication ability when performing core basic nursing skills in fundamental nursing practice education. The communication ability evaluation tool was constructed based on a literature review and expert advice. The tool was applied to test 94 students who were taking fundamental nursing practice courses from October to November 2019. As a result, five factors (self-introduction, eye contact, emotional support, information provision, and therapeutic touch) were derived as evaluable items of communication ability to be evaluated when performing core basic nursing skill, and were evaluated when performing core basic nursing skills to measure vital signs. The average communication ability was 3.96 out of 5 points. According to the rubric, 95.8% of all students attained 'medium' and reached their goal achievement level. The findings of this study are meaningful in providing an important basis for improving the performance outcome evaluation process and for constructing a systematic evaluation system in fundamental nursing practicum. Further studies to secure the validity and reliability of this communication ability evaluation tool and comparative studies with various evaluation tools are suggested.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.2107-2118
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• 2020

The nuclear reactor coupled with supercritical carbon dioxide (S-CO₂) Brayton cycle has good prospects in generation IV reactors. Turbomachineries (turbine and compressor) are important work equipment in circulatory system, whose performances are critical to the efficiency of the energy conversion system. However, the sharp variations of S-CO₂ thermophysical properties make turbomachinery performances more complex than that of traditional working fluids. Meanwhile, almost no systematic analysis has considered the effects of turbomachinery efficiency under different conditions. In this paper, an in-house code was developed to realize the geometric design and performance prediction of S-CO₂ turbomachinery, and was coupled with systematic code for Brayton cycle characteristics analysis. The models and methodology adopted in calculation code were validated by experimental data. The effects of recompressed fraction, pressure and temperature on S-CO₂ recompression Brayton cycle were studied based on detailed design of turbomachinery. The results demonstrate that the recompressed fraction affects the turbomachinery characteristic by changing the mass flow and effects the system performance eventually. By contrast, the turbomachinery efficiency is insensitive to variation in pressure and temperature due to almost constant mass flow. In addition, the S-CO₂ thermophysical properties and the position of minimum temperature difference are significant influential factors of cyclic performance.

• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.348-360
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• 2015

Objectives From observing the tongue of a patient, one can assess the health status; this method has been frequently used in traditional Korean Medicine (KM) clinics. In particular, KM posits that the color of the tongue is highly related to digestive functions. In this study, the color of tongue and heart rate variability (HRV) were compared between chronic dyspepsia (CD) patients and healthy subjects. Methods Healthy subjects and CD patients with functional dyspepsia (FD), gastroesophageal reflux disease (GERD), or chronic gastritis (CG) were enrolled for the study. Profile view images of the tongue were acquired by using a computerized tongue image acquisition system (CTIS). The color of the tongue body was extracted from the non-coated region on the tongue images. Results Color differences in CIE L*a*b* color space between the three sub-types of CD patients and healthy subjects were analyzed by using multiple linear regression analysis with age and sex as the factors. The variable b* was significantly lower in GERD patients than in the controls (p=0.017). Variable a* was significantly lower in CG than in the controls (p=0.03). No significant difference was seen between FD and controls. In GERD, the tongue body seems to be intense red in color; in CG, pale red. Frequency domain analysis showed that HF was significantly lower in GERD patients than in the controls (p=0.041). Conclusions The color of the tongue body and HF of HRV can be used for diagnosing digestive functions in health care.

• Culinary science and hospitality research
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• v.12 no.3 s.30
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• pp.1-16
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• 2006

This study investigates the level of customers' preferences for the menu at rice cake cafes. The study aims at examining the potential of restaurants with rice cake dishes and suggesting the ways to contribute to the potential. For this study, various rice cake cafes in Seoul which were often mentioned in the Internet portal sites and mass media are selected such as Jilsilu, Midan, Yaemunbyeonggwa, and Howeondang. Some of the customers in these rice cake cafes from August 16th to 26th in 2005 are the participants in this study. Using Windows SPSS 11.0 for statistical analysis, the validity of the items in the questionnaire is tested through Cronbach's Alpha which also reveals the internal reliability. Variables are analysed to eliminate less important variables. In order to examine the differences between groups by norm population profiles, t-test and ANOVA are conducted. For obtaining the degree of impact of rice cake cafe preference variables on the satisfaction in the rice cake cafe, regression analysis is carried out. As a result, for preferences for dishes, 19 variables among 22 are identified and divided into four factors which are named as 1) fundamental factor, 2) external factor, 3) appearance factor, and 4) structural factor. The fundamental factor, external factor, appearance factor, and structural factor are all significantly influential to the level of satisfaction with the menu, yet the fundamental factor is the most powerful factor among them.

• The Journal of Korean Medicine
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• v.36 no.3
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• pp.23-34
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• 2015

Objectives: This study is aimed at assessing the reliability of a standard instrument of diagnosis and assessment for Spleen Qi deficiency pattern questionnaire (SQDQ) and examining the validity of the SQDQ by comparing the pattern identification scores of different groups. Methods: We conducted a survey of 72 participants (60 patients with chronic dyspepsia and 12 healthy subjects) using self-reported questionnaire. Participants were given written consent and this study was performed under the permission of institutional review board of Kyung-Hee university Korean medicine hospital. Results: The reliability and the validity of the questionnaire were inspected. Internal consistency of the SQDQ was excellent. Construct validity analyzed by exploratory factor analysis produced 4 factors, which were selected from eigenvalues that are greater than 1.0. The factor 1, 2, 3 and 4 showed 'fatigue', 'meal', 'diagnosis' and 'figure' respectively. For most of SQDQs' items, there were significant differences observed between the Spleen Qi and the non-Spleen Qi groups. However, the 'emaciation', 'tongue diagnosis' and 'pulse diagnosis' showed no significant differences. Conclusions: The SQDQ restructured in this study may provide a fundamental questionnaire and a further study is required for a more advanced, standardized and statistically proven questionnaire.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.169-177
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• 2005

This study is to analyze the application of the oyster shells as a substitute fine aggregate of concrete. For this purpose, the fundamental experiments of the composed materials and the variations of the main factors on it were considered and then the variations of workability and strength properties of the specimens with each case were also studied. The experimental results on the properties as construction material showed that the use of oyster shells in concrete would not cause abnormal chemical reactions or lead to the formation of any new objects, the workability and strengths decreased with increase in proportion of oyster shells. The compressive strength of concrete with oyster shells is developed as much as that of normal concrete and the grain size of oyster shells is superior on 3.0~5.0mm and the percentage of substitution of them to fine aggregate about 30% from the properties of concrete with them. The relationship equation between compressive strength and tensile strength is ( ).

• Journal of the Korean Institute of Educational Facilities
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• v.10 no.4
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• pp.5-20
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• 2003

The purpose of the research on the noise of educational facilities is to build up pleasant environments by minimizing the influence on the students in the school. This study provides fundamental data for acoustic design by measuring, computer simulation and analyzing the room acoustic characteristics of the lecture room in middle school. For measurement on the factors of room acoustic, RT of lecture room and noise reductions depending on various walls of different structures were measured and analyzed. The lecture system being installed and carried out on the normal lecture room was divided into 4 types-employment of multimedia machines, employment of multimedia machines and loud speakers, employment of loud speaker, and existing verbal speaking-and SPL for each type was measured and analyzed. Based on the measured characteristics of acoustic characteristics for normal lecture room, the problems for environment of noise were understood through computer simulation, applications for improvements of performance for each facility were studied, schemes for improvements of performance by using the effects were presented, necessary fundamental data were secured, and schemes to enhance flexibility on the existing facilities of school against changing educational courses were secured.