• Computers and Concrete
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• v.28 no.5
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• pp.479-486
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• 2021

Reinforced concrete (RC) slabs are exposed to several static and dynamic effects during their period of service. Accordingly, there are many studies focused on the behavior of RC slabs under these effects in the literature. However, impact loading which can be more effective than other loads is not considered in the design phase of RC slabs. This study aims to investigate the dynamic behavior of two-way RC slabs under sudden impact loading. For this purpose, 3 different simply supported slab specimens are manufactured. These specimens are tested under impact loading by using the drop test setup and necessary measurement devices such as accelerometers, dynamic load cell, LVDT and data-logger. Mass and drop height of the hammer are taken constant during experimental study. It is seen that rigidity of the specimens effect experimental results. While acceleration values increase, displacement values decrease as the sizes of the specimens have bigger values. In the numerical part of the study, artificial neural networks (ANN) analysis is utilized. ANN analysis is used to model different physical dynamic processes depending upon the experimental variables. Maximum acceleration and displacement values are predicted by ANN analysis. Experimental and numerical values are compared and it is found out that proposed ANN model has yielded consistent results in the estimation of experimental values of the test specimens.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.458-464
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• 2022

Hazard recognition is considered as one of the pre-requisites for effective hazard management and injury prevention. However, in complex and changing environments, construction workers are often unable to identify all possible hazards that can occur in the jobsite. Therefore, identification of factors that impact hazard recognition in the work environment is necessary to reduce safety incidents as well as to develop strategies that can improve worker's hazard recognition performance. This study identified factors/problems that impact worker's hazard recognition abilities and suggested some potential technologies that can mitigate such problems. Literature reviews of journal articles and published reports related to hazard recognition studies were conducted to identify the factors. The study found out that the major factor responsible for affecting worker's hazard recognition abilities were human-related. Industry factors, Organizational factors and Physical factors of the site were the other factors identified from the study that impact worker's hazard recognition performances. The findings from the study can help site personnel recognize areas where effective measures can be directed towards worksite safety of workers while working in complex construction environments.

• The Journal of Industrial Distribution & Business
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• v.15 no.1
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• pp.1-8
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• 2024

Purpose: The purpose is to investigate the types of communication between aviation industry workers and passengers according to environmental changes following the COVID-19 pandemic. This study analyzes the impact of verbal and non-verbal communication styles of airport staff, especially those working at airline check-in counters, on passenger satisfaction. Research Design: The research design focuses on the impact of verbal communication styles and non-verbal communication factors of airline check-in counter staff, who represent the initial point of contact with passengers among airport staff, on passenger satisfaction. The survey period for sample collection was from July 1 to July 30, 2023, and the study was conducted targeting passengers boarding aircraft through Incheon Airport and Gimpo Airport. Result: First, it is important for airport staff to recognize all passengers, especially corporate customers, as corporate customers rather than simply as individuals boarding an airplane. Second, as the importance of non-verbal expressions increases due to the impact of COVID-19, physical and verbal responses are necessary. Third, it is important to check which language the passenger understands. Conclusions: Since communication through nonverbal expressions has become more important since COVID-19, airport employees need to recognize the importance of nonverbal communication. This awareness can serve as a foundation for building trust between airport staff and passengers.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.334-344
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• 2024

In Dangjin, Chungcheongnam-do, there are not only power plants and large steel complexes, but also small and medium-sized air pollutant emission facilities. The dust generated by these facilities has a very small particle size and a large surface area due to condensation and physical and chemical reactions, and is discharged containing various harmful substances. Therefore, this study analyzed the distribution of particulate matter and heavy metal concentrations by particle size in the vicinity of the steel complex, residential area, and reference point using an eight-stage Cascade Impactor. Overall, the direct impact sites with a short distance from the steel complex had the highest concentration, followed by the indirect impact sites, and the non-impact sites had the lowest concentration, indicating that they are directly affected by the steel complex. The atmospheric dust concentration distribution showed a bimodal distribution with a minimum value around the 1.1 to 2.1 ㎛ particle diameter. However, during the yellow dust event, the maximum concentration was biased toward coarse particles. The proportion of PM2.5 in the dust tended to be higher in winter, while the ratio between PM2.5 and PM10 was relatively higher in spring. Regardless of the location of the impact point, heavy metals in the dust were dominated by iron and aluminum, followed by zinc, lead, and manganese.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.561-569
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• 2015

This study looks into the level of anxiety that middle school students have about PE class, dividing the classes into coed class and single-sex class and aims to conduct an in-depth analysis of differences in sub-factors of the anxiety. Subjects of the study were 554 students in randomly selected six middle schools located in Gyeonggi-do. To figure out the relationships among the sub-factors of the anxiety according to class, grade, academic record and the level of physical strength, a Multivariate Analysis of Variance model was set up and analysis was conducted. The results obtained through the research are as follows. First, it was predicted that the level of anxiety about PE class in middle school would have a great impact on the factor, 'punishment' by class (coed and single-sex). Second, it was predicted that the level of anxiety about PE class in middle school would have a great impact on the factors, 'anxiety about the event of sports' and 'conflict during class' by grade. Third, it was found that there was no difference in the level of anxiety about PE class that middle school students had according to their academic record in PE. Fourth, it was predicted that the level of anxiety about PE class in middle school would have a great impact on the factor of 'anxiety about the event of sports' by the level of physical strength.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.175-183
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• 2010

Purpose: This study investigated the impact of ametropia and myopia on health-related quality of life (QoL) measures in elementary schoolers. Methods: Elementary school children of 92 aged 12 to 13 were divided into emmetropia and myopia groups by spherical equivalent. Then myopia was classified into the low, moderate and high myopia groups. Vision-related QoL scores were determined using PedsQL 4.0 (Pediatric Quality of Life Inventory) with physical health (8 items), emotional functioning (4 items), social functioning (5 items) and school functioning (5 items). Results: The total QoL score in the myopia group appeared lower than that in the emmetropia group, however the difference was not statistically significant (p>0.05). When it comes to physical health (running or exercising) and social functioning (getting along with friends or being teased)-related questions, the QoL score in myopia was low compared with the emmetropia group (p<0.05). High myopia showed a low score in physical health items but there was no significant difference in overall QoL scores in comparison with other groups (p<0.05). Conclusions: Refractive errors does not have a great impact on the total health-related QoL in elementary school children but it causes discomfort in physical health and social functioning.

• The Journal of Industrial Distribution & Business
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• v.9 no.6
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• pp.65-76
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• 2018

Purpose - The study aims to provide the relationships between the social servicescape and customer's emotion and voluntary behaviors were investigated in this study. The social servicescape was largely divided into service employee's image and other customers (in customer's similarity, physical appearance and suitable behavior). Firstly, the relationship between service employee's image and customer's positive emotion was investigated as a specific purpose of study. Secondly, this study attempted to understand the relationship between other customers (in customer's similarity, physical appearance and suitable behavior) and customer's positive emotion. Lastly, the relationship between customer's positive emotion and customer's voluntary behavior dimension (intention to cooperate, intention to participate in and loyalty) was examined. Research design, data, & methodology - In order to prove the hypotheses in this study, the customers who have experienced family restaurants during the last two months were targeted for a survey. A total number of 300 survey papers were distributed and as a result, 248 papers could be used for analysis, except the papers with insincere answers. After the analysis of the reliability and validity of each major variable, the hypothesis was verified through the structure method by using Amos 20.0. Results - First, the results of hypothesis testing on the relationship between social servicescape and customer's positive emotion showed service employee image gives a positively meaningful impact on customer's positive emotion. Secondly, the results on the relationship between other customers and customer's positive emotion indicated that the customer's similarity and physical appearance has a positively significant impact on customer's emotion while customer's suitable behavior has not a significantly positive impact on customer's positive emotion Lastly, customer's positive emotion was shown to have a significantly positive influence on customer's voluntary behavior dimension, that is, intention to cooperate, intention to participate in and loyalty. Conclusions - This study aims to focus on and emphasize the social servicescape and its importance, which is different from the previous studies that have been focused largely on physical servicescape. Such results in this study indicated the social servicescape (service employee's image and other customers) as an important factor that affects customer's positive emotion and voluntary behavior.

• Korean Journal of Applied Biomechanics
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• v.23 no.1
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• pp.25-35
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• 2013

This study examined 24 right-handed amateur baseball players. Twelve who had played baseball for more than 6 years were grouped as skilled players, while 12 who had played for 1-3 years were the unskilled player group. The swing motion was divided into four event phases: stance, backswing, impact, and follow-through. The mean and maximum plantar pressure, center of pressure, and ground reaction force were measured during each event phase. The mean and standard deviations for each variables were calculated and differences were validated with the independent sample t-test. A p-value <0.05 was considered statistically significant. The results were as follows. 1)The ideal stance is a stable, balanced position with more than 65% of weight on the right foot. There was significant difference in mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significant. 2)The effective backswing of a skilled player is comprised a rightward shift in weight to build maximum energy. More than 90% of the weight was on the right foot. There was a significant difference in the mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significantly. 3) For an effective impact, a rapid shift in weight to the left foot is essential, so that a power hit is obtained. Significant difference in the mean and maximum plantar pressures of both feet were observed. 4)Follow-through requires wight balance, more on the right than the left, without leaning leftward. There was no significant difference in the mean or maximum plantar pressure. 5)The center of plantar pressure should move from the center of the foot to the toe. 6)The analyses of the ground reaction force suggest that a good swing involves a gradual shift in weight to the right side and a rapid leftward shift at impact. Good balance, with the center of gravity on the right side at follow-through, is also required.

• Journal of Preventive Medicine and Public Health
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• v.46 no.2
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• pp.89-95
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• 2013

Objectives: Little is yet known about the determinants of bone mineral density (BMD) in young adults. Thus, in this study, we aimed to determine the factors that have an impact on BMD in young men. Methods: Questionnaires were sent out to 111 male medical students. Information on age, socio-economic status, medical history, lifestyle, physical activity during adolescence, school club participation, current physical activity, and dietary intake were collected by the survey. Height, weight, percent body fat and muscle mass were estimated by bioelectrical impedance, and BMD was obtained using calcaneal quantitative ultrasound. Using the Poisson regression model, prevalence ratios (PRs) were used to estimate the degree of association between risk factors and osteopenia. Results: The height and current physical activity showed a correlation to the Osteoporosis Index. Among the categorized variables, past physical activity during adolescence (p= 0.002) showed a positive effect on the bone mineral content. In the multivariate model, past physical activity (${\geq}1$ time/wk) had a protective effect on osteopenia (PR, 0.37; 95% confidence interval [CI], 0.18 to 0.75) and present physical activity (1000 metabolic equivalent of task-min/wk) decreased the risk of osteopenia (PR, 0.64; 95% CI, 0.44 to 0.91). Conclusions: Past physical activity during adolescence is as important as physical activity in the present for BMD in young men.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.43-50
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• 2014

The purpose of this study was to analyze of the GRF (ground reaction force) parameters according to the change of positions and weights of bag during downward stairs between dominant and non-dominant in upper & lower limbs. To perform this study, participants were selected 9 healthy women (age: $21.40{\pm}0.94yrs$, height: $166.50{\pm}2.68cm$, body mass: $57.00{\pm}3.61kg$, BMI: $20.53{\pm}1.03kg/m^2$), divided into 2 carrying bag positions (dominant arm/R, non-dominant arm/L) and walked with 3 type of bag weights (0, 3, 5 kg) respectively. One force-plate was used to collect GRF (AMTI OR6-7) data at a sample rate of 1000 Hz. The variables analyzed were consisted of the medial-lateral GRF (Fx), anterior-posterior GRF (Fy), vertical GRF (Fz), impact loading rate and center of pressure (COPx, COPy, COP area, COPy posterior peak time) during downward stairs. 1) The Fx, Fy, Fz, COPx, and COP area of GRF were not statistically significant between dominant leg and non-dominant leg, but non-dominant leg, that is, showed the higher COPy, and showed higher impact loading rate than that dominant leg during downward stairs. 2) In bag wearing to non-dominant arm, Fx, Fz, COPx, COPy, impact loading rate and COP area showed increase tendency according to increase of bag weights. Also, against bag wearing to dominant arm, non-dominant showed different mechanism according to increase of bag weights. The Ground Reaction Force parameters showed different characteristics according to the positions and weights of bag during downward stairs between dominant and non-dominant arm.