http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Seunghyeon Cho,Hankun Yeon,Hyunho Kim,김창완 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3
MacPherson strut suspension, which is widely used vehicle suspension type, decreases the riding comfort and durability of strut module due to the side load generated at the damper. In this study, a method for designing a C-type side load coil spring is proposed to reduce the side load, considering not only the centerline shape, but also the end coil angular position of the spring. The effect of end coil angular position as well as centerline shape on the force axis are analyzed through finite element analysis (FEA) and regression analysis. Formulas are established based on the analyses and the C-type coil spring was designed considering the effects of both design variables on the force axis. Then, the side load of the MacPherson strut suspension on which the designed C-type side load coil spring was mounted was calculated by using the flexible multibody dynamic analysis method. Finally, a side load reduction effect of C-type side load coil spring is analyzed by comparing with that of helical-type coil spring.
Seunghyeon Cho,Won-Ju Park,Wonyang Kang,Hyeong-Min Lim,Ji-Sung Ahn,Dae-Young Lim,Jai-Dong Moon 대한직업환경의학회 2019 대한직업환경의학회지 Vol.31 No.-
Background: Dehydroepiandrosterone sulfate (DHEAS) is an endogenous steroid hormone produced by the adrenal gland. DHEAS has been suggested to play a protective role against psychosocial stress. The aim of this study was to investigate the association between job-related stress and blood concentrations of DHEAS according to occupational stress factors among female nurses. Methods: A cross-sectional study was conducted among 118 premenopausal nurses from 4 departments (operating room, emergency room [ER], intensive care unit, and ward) of a university hospital. Participants were all rotating night shift workers who have worked for over a year and mean age of 33.5 ± 4.8 years. Data from structured questionnaires including the Korean Occupational Stress Score, Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and Pittsburgh Sleep Quality Index (PSQI) were used. Results: In the high job-related stressor group, scores of BDI, BAI, and PSQI were significantly higher than low-stressor group. ER nurses had relatively more work-burden related stressors, but they had significantly lower levels of anxiety and depression than other groups. And, ER nurses showed higher levels of DHEAS than the other department nurses. The differences were significant (p = 0.003). Additionally, there was a statistically significant difference even after adjusting for factors that could affect level of DHEAS, such as age, body mass index, drinking, and physical activity (p = 0.039). Conclusions: This result suggests the possibility that DHEAS may play a role as a marker of proper stress management. The capacity to secrete DHEAS is not simply due to workload or job stressor but could be determined depending on how individuals and groups deal with and resolve stress. Proper resolution of stress may affect positive hormone secretion.
Night shiftwork and prostate-specific antigen level in a tire manufacturing factory
Seunghyeon Cho,Won-Ju Park,WonYang Kang,Dae-Young Lim,Suwhan Kim,Jai-Dong Moon 대한직업환경의학회 2019 대한직업환경의학회지 Vol.31 No.-
Background: Recent studies suggest that night shiftwork may increase the risk of prostate cancer and elevated serum prostate-specific antigen (PSA) level. The purpose of this study was to verify whether rotating night shiftwork affects serum PSA level. Methods: This study included 3,195 male production workers who work in a large tire manufacturing factory. Serum PSA levels were measured and the data on related factors were obtained. Results: The mean serum PSA level was 0.98 ± 0.79 ng/mL. PSA levels were significantly lower in the younger age group, the obese group, and regular exercise group. PSA levels were lower in night shift workers (n = 2,832) compared to day workers (n = 363), but the difference was not statistically significant. Conclusions: Unlike previous studies, we did not find any evidence that night shiftwork results in an increase in serum PSA levels. Further research and consistent results are needed to elucidate the association between night shiftwork and the effect on the prostate.
EFFECTS OF SOCIAL MEDIA POSTING ON EXPERIENTIAL ASPECTS OF MATERIAL PRODUCTS AND LIKING OF THEM
Seunghyeon Cho,Jeonghwa Seo,Hakkyun Kim,Sangdo Oh 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07
Studies regarding the relationship between purchases and happiness have consistently found an experiential advantage: people are happier when purchasing experiential products (e.g., vacations and concerts) than material products (e.g., clothes and electronics) (Caprariello & Reis, 2013; Carter & Gilovich, 2010, 2012; Pchelin & Howell, 2014; van Boven and Gilovich, 2003). This phenomenon (i.e., experiential advantage) may make marketing efforts of service firms or any companies selling experiences relatively more effective and productive in that consumers will derive a great amount of purchase happiness. On the other hand, the same phenomenon may indicate innate challenges and hurdles for firms selling products carrying materialistic features. Considering the material-experiential spectrum, approximately 50% of the industries are seeming faced with this issue. In this research, we propose a solution with which mainly material-focused products can loom more experiential, thereby benefiting from the experiential advantage. In other words, we investigate how material goods can be perceived as experiential and they can offer greater purchase satisfaction compared to when they remain as merely materialistic. Specifically, noting that reasons for experiential advantages are originated from social aspects of experiential goods (e.g., self-presentation to other people, conversational values, reputation-building, etc.), the current study shows that posting on social media can imbue social aspects, which is a key drive of the experiential advantage.
Cho Seunghyeon,전경훈,김창완 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.2
In this study, we develop flexible multibody dynamic-electromagnetic-structural vibration coupled analysis method to accurately predict motor vibration by considering the electromagnetic force characteristics, rotating characteristics of rotating motor motors, and their interactions at the no-load rated speed and operating speed range. The structural characteristics are accurately reflected by developing a three-dimensional (3D) finite element model considering the entire components of the motor. The reliability of the 3D finite element model of the motor is verified using the impact hammer test. In addition, to consider the rotational characteristics of the rotor structure, we develop a flexible multibody dynamics model that connects the flexible rotor and the bearing with revolute joint. The vibration of the motor at the no-load rated speed is analyzed using flexible multibody dynamics-electromagnetic-structural vibration coupled analysis. Comparing the vibration test results, it is confirmed that the flexible multibody dynamics-electromagnetic-structural vibration coupled analysis result predicts the actual motor vibration more accurately than the conventional finite element analysis-based electromagnetic-structural vibration coupled analysis result. By using flexible multibody dynamics-electromagnetic-structural vibration coupled analysis in the operating speed range, it is confirmed that not only electromagnetic force harmonics but also sideband harmonics caused by rotor eccentricity-induced large vibrations, and also confirmed that it accurately predicts the vibration characteristics of actual motors with rotating rotors.