• Journal of the Korean Society of Safety
• /
• v.31 no.3
• /
• pp.82-88
• /
• 2016

Ballasted gravel will be damaged or worn by the repetitive train load. And these damages of ballast gravel could be increased by increasing vehicle speed. Therefore, various techniques for reducing the ballast pressure have been proposed, such as the attached pad type of sleeper bottom for ballasted track. In this study, spring stiffness test method were proposed to evaluate the performance of under sleeper pad for ballasted track. Standard ballast plate(SBP) was developed to simulate the ballast gravel and compared with the foreign test results. Experimental results showed a trend similar to the previous studies according to various loading plate type. specimen type(Type A, Type B) differences in spring stiffness according to hardness were not significant. Also, the FSP (Flat steel plate) - shaped jig is about 80% of the spring stiffness was greater than SBP. Therefore, to evaluate the actual spring stiffness of under sleeper pad for ballasted track, it was important to adopted the appropriate spring stiffness test method using the SBP to simulate actual field conditions.

• Journal of the Korean Society of Safety
• /
• v.34 no.5
• /
• pp.103-110
• /
• 2019

In order to reduce the accidents occurring at construction sites, it is necessary to approach with harmonious measures considering various aspects such as systems, training, facilities, and protection equipments. Suggestion of safe construction method can be a good alternative. In the previous study, the half-depth precast deck with RC rib panel was proposed as an alternative method for safe bridge deck construction, and the performance required by the design code was verified through a four-point bending test. But the actual bridge deck is subjected to the repetitive action of the wheel load rather than the bending condition due to the four-point load. In this study, fatigue test was performed by repeating the wheel load $2{\times}10^6$ cycles to verify the safety of the half-depth precast deck with RC rib panel under actual conditions. As a result, fatigue effect due to repetition of wheel load was not significant in terms of serviceability such as crack width and deflection. In the residual strength test conducted after the fatigue test, the half-depth precast deck with RC rib panel failed by punching shear which is typical failure mode of bridge decks and the residual strength was similar to the punching strength of the RC and PSC bridge decks in spite of the fatigue effects.

• Journal of Fashion Business
• /
• v.27 no.2
• /
• pp.52-69
• /
• 2023

Based on five types of health KF masks currently being commercialized, this study analyzed results of a survey of 316 male and female college students with experience in wearing health masks in Seoul metropolitan area. By identifying problems and improvement requirements according to current status of wearing health masks, results of this study could be used as basic data for designing ergonomic health mask with improved ease of wearing and satisfaction for human safety protection in the future. SPSS 26.0 statistical program was used for all data analyses, including post-hoc test, χ² test for cross-analysis, frequency analysis, independent samples t-test, ANOVA, and Duncan test. Considering that masks are worn for more than 8 hours a day on average, it is necessary to design masks considering materials, sizes of mask ear straps, elasticity and thickness of straps. The design should minimize contact with lips and cheeks with improved fit and comfort, blocking performance, and aesthetics. According to this survey, nearly 50% of respondents said they were willing to wear masks even after the end of COVID-19. Thus, it is necessary to perform research and improve masks to have excellent colors, designs, shapes, fit, and functions suitable for both pandemic and post-pandemic era when wearing masks is common.

• Journal of the Korean Society of Systems Engineering
• /
• v.19 no.1
• /
• pp.107-113
• /
• 2023

For one-shot systems such as 81mm high-explosive ammunition, research on performance prediction is insignificant due to research manpower infrastructure and lack of interest and difficulties in securing field data, which can only be done by special task workers. In order to evaluate the actual range of ammunition, the storage ammunition reliability evaluation checks the range by firing actual ammunition through a functional test. Test evaluation is a method of extracting a sample from the population, launching it, and recording the results accordingly. As a result of these tests, the range, which is an indicator of ammunition performance, can be measured differently according to meteorological factors such as temperature, atmospheric pressure, and humidity according to the location of the test site. In this study, various environmental factors generated at the test site and storage period analyze the correlation with the range, which is the performance of ammunition, and analyze the priority of importance for each factor and the numerical standards that environmental factors affect range. Through this, a new approach to one-shot system performance prediction was presented.

• Journal of Distribution Science
• /
• v.17 no.12
• /
• pp.63-70
• /
• 2019

Purpose: This study was to propose effective deployment of automatic external defibrillators (AEDs) installed at general supermarkets. Research design, data, and methodology : We conducted interview and data surveys on 72 large distributors in Seoul and Gyeonggi province in South Korea. The content of this survey was consisted of general status on the general supermarkets, AED deployment and management regarding public access defibrillation (PAD). G^⁎Power (v 3.1.9.4; Universität Kiel, Kiel, Germany) was also used to analyze statistical power. Radius and actual distance, radius and retrieval time were compared by t-test at α=.05. respectively. Results : Difference between the radius (102.7 meters) and the actual distance (187.8 meters) was 85.1m, it had statistically significant difference (p<.001). The actual distance was longer compared to the radius distance. Difference between the radius (114.1 seconds) and the retrieval time (208.7 seconds) was 94.6s, it had statistically significant difference (p<.001). The retrieval time took longer compared to the radius time as well. Conclusions : The finding shows that only 45.9% of the general supermarkets are satisfied with the actual AED coverage within 3 minutes. This needs to enhance AED deployment to reduce defibrillation time and AED management to boost application in South Korea.

• Journal of Korean Biological Nursing Science
• /
• v.18 no.3
• /
• pp.160-168
• /
• 2016

Purpose: This study was conducted to examine the pro-environmental attitude (actual commitment domain, verbal commitment domain, affect domain), behavior to decreased exposure and knowledge of endocrine disruptors by obesity -related profiles (BMI, body fat percentage, visceral fat percentage, skeletal muscle mass percentage, waist circumference, waist-hip ratio). Methods: A cross-sectional study was conducted with 102 nursing students. Data were collected from November to December, 2015 using self-report questionnaires and physical measurements. Data were analyzed using t-test, Pearson correlation and coefficients with SPSS 18.0. Results: The study results showed that actual commitment domain of pro-environmental attitude and behavior to decreased exposure level on endocrine disruptors were significantly related to visceral fat percentage. Actual commitment domain of a pro-environmental attitude was significantly related to body fat percentage. Pro-environmental attitude was significantly related to the behavior to decreased exposure level on endocrine disruptors and knowledge thereof. Conclusion: These findings suggest that visceral fat and body fat percentages were significantly related to the actual commitment domain of a pro-environmental attitude. Therefore, a replication study is recommended to understand the connection between endocrine disruptors and obesity. In addition, developing an education program about endocrine disruptors for nursing students is recommended. In particular, a pro-environmental attitude, especially on actual commitment domain, could be involved as an education program.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.23 no.1
• /
• pp.48-56
• /
• 2017

Purpose: This study was conducted to identify the relationships between the perceived and actual achievement on skill performance assessment and identify the relation to learning motivation factors. Methods: A total of 80 senior nursing students currently studying at a university participated in the study in 2015. Students completed a performance examination of 20 nursing skills at the end of their 7-week training period; their performance was rated using checklists. Students then completed a survey, which included questions about learning motivation and perceived achievement level. Data were analyzed by descriptive statistics, Pearson's correlation, and Kruskal-Wallis test. Results: There was a weak correlation between perceived and actual achievement. Intrinsic and extrinsic goal-orientation and self-efficacy in learning motivation factors was significantly correlated to perceived achievement. Perceived achievement and self-efficacy in middle quartile of actual achievement were higher than other upper- or lower-quartile group. Conclusion: The findings suggest that the motivation factors of learners should be taken into account to maximize academic achievement in nursing skills training. In addition, it should be considered a strategy to reduce the gap between perceived and actual achievement.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1994.04a
• /
• pp.187-190
• /
• 1994

During the initial design phases for prestressed concrete structures, the mecessary information concerning the physical properties of the hardened concrete such as creep, drying shrinkage, modulus of elasticity, and Poisson's ratio are obtained from design assumptions or accepted standards. But these assumptions may not totally reflect the actual long-term behavior of the concrete. So they may be of limited use in predicting the actual behavior. The purpose of this paper is to describe the test procedures and methods of evaluation which were used during the long-term study.

• Communications for Statistical Applications and Methods
• /
• v.4 no.2
• /
• pp.589-610
• /
• 1997

When a modeling process is applied to an actual commodity market in the real world, interactions over closely related commodities through the marketing channel should also be formulated into the model to reflect the information that exists in the whole market system, otherwise unreliable estimates and test statistics may be produced by ignoring those effects. Single-equation type model in this case tends to yield inefficient estimates, and sometimes biased and inconsistent, which will mislead us. A system of equation method to examine the structure of the imported commodity market system is developed and its emtirical results are analyzed, then followed by some policy experiments and its implications.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.747-750
• /
• 1995

As railway trains run faster high performance braking system are necessary because more energy needs to be dissipated due to increased kinetic energy. In this work a portable computer based prediction system for emergency braking distance has been developed. The algorithm for the system is based on braking theory and empirical results of actual braking test. The computer is connected to the sensors to measure the velocity and the braking pressure in real train. It is expected that this system will be utilized to predict emergency braking distance during actual operation of the train