• Journal of Ecology and Environment
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• v.41 no.10
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• pp.281-289
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• 2017

Background: In this study, the growth and reproductive response of seedlings, grown in plastic pots with sand, to moisture and nutrients were analyzed in order to study the environmental conditions required to create an alternative habitat for Epilobium hirsutum L., an endangered plant. Results: Vegetative and reproductive growths of Epilobium hirsutum L. are accelerated with increase in moisture and organic matter content in the soil. Among vegetative organs, the number of runners related to asexual reproduction was the highest when the moisture content was over 25% and nutrient content between 7 and 14% in the soil. But the number of flowers related to flowering responses, among reproductive organs, was the highest when the moisture content was maintained at 75% and when nutrient content was 21% in the soil. The number of seeds, related to sexual reproduction, was the highest when the moisture content was over 25% and nutrient content between 14 and 21%. Conclusions: The study results show that a place with high moisture and nutrient content in the soil is advantageous to asexual and sexual reproduction of Epilobium hirsutum L. Therefore, we must serve periodically nutrient and seeds to sustain population in in situ conservation. Furthermore, it is advisable to create in riverside where abundant nutrient content have, making alternative habitat of Epilobium hirsutum L. Also, we must find species that have high contribution degree index through vegetation survey.

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.321-330
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• 2016

Run expectancy (RE) is the mean number of runs scored from a specific base runner/outs situation of an inning to the end of the inning. Win expectancy (WE) is the probability that a particular team will win the game at a specific game state such as half-inning, score difference, outs, and/or runners on base. In this paper, we derive RE and WE for the Korea Baseball Organization (KBO) League based on six-year data from 2007 to 2012 using a Markov chain model.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.93-105
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• 2008

This study was for the analysis of Kinematic variables, using 3 types of starting block position setting(25cm, 40cm, 35cm). The subjects of the study were 8 short-distance male runners. In the study, the most desirable block setting type for the runner who were average 180cm tall to get the good record was 45cm (distance between the starting line and the front block) and 40cm (distance between the blocks). In conclusion, the most favorable start in 100m race was to get the strongest propelling power at the start line. The most important technical point was quick responding ability to the start signal and reaching the maximum speed at the shortest time through the strong kick using the front leaning body angle and gravity. Type B start method has shown the most effective results for the improvement of the records in the 100m race.

• Korean Journal of Applied Biomechanics
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• v.30 no.2
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• pp.145-154
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• 2020

Objective: The purpose of this study was to determine the relationship between impact and shear peak force, and tibia-accelerometer variables during running. Method: Twenty-five male heel strike runners (mean age: 23.5±3.6 yrs, mean height: 176.3±3.3 m/s, mean mass: 71.8±9.7 kg) were recruited in this study. The peak impact and anteroposterior shear forces during treadmill running (Bertec, USA) were collected, and impact shock variables were computed by using a triaxial accelerometer (Noraxon, USA). One-way ANOVA was used to test the influence of the running speed on the parameters. Pearson's partial correlation was used to investigate the relationship between the peak impact and shear force, and accelerometer variables. Results: The running speed affected the peak impact and posterior shear force, time, slope, and peak vertical and resultant tibial acceleration, slope at heel contact. Significant correlations were noticed between the peak impact force and peak vertical and resultant tibia acceleration, and between peak impact average slope and peak vertical and resultant tibia acceleration average slope, and between posterior peak (FyP) and peak vertical tibia acceleration, and between posterior peak instantaneous slop and peak vertical tibial acceleration during running at 3 m/s. However, it was observed that correlations between peak impact average slope and peak vertical tibia acceleration average slope, between posterior peak time and peak vertical and resultant tibia acceleration time, between posterior peak instantaneous slope and peak vertical tibial acceleration instantaneous slope during running at 4 m/s. Conclusion: Careful analysis is required when investigating the linear relationship between the impact and shear force, and tibia accelerometer components during relatively fast running speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2635-2640
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• 2014

Lee Ritenour and Larry Carlton were the most popular contemporary guitarists. So we can find they have something in common in many ways. Also their abundant experiences and know-how made their own music into Fusion Jazz. They always tried to make new approach specializing Fusion Jazz genre, which makes us realize that they are the front runners of Contemporary Jazz mixing music with the situation of the time. This paper analyzes harmonic parts and arranged parts these two guitarists show and studies the musical meaning and characteristics their representative albums have. Also this paper focuses on some developments and growth by examining the relationship between these two guitarists.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.589-596
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• 2021

In this study, the optimum gating system was designed, and the two zinc alloy worm gears were manufactured in single process by applying a symmetrical gating system with 2 runners. The SRG ratio is set to 1 : 0.9 : 0.6, and the cross-sectional shapes such as sprue, runner and gate are designed. In order to determine whether the design of the gating system is appropriate, casting analysis was carried out. It takes 4.380 s to charge the casting 100%, 0.55 to 0.6 m/s at the gates and solidification begins after the casting is fully charged. The amount of air entrapment is 2% in the left gear and 6% in the right gear. Hot spots occurred in the center hole of the gear, and pores were found to occur around the upper part of the hole. Therefore, the design of the casting method is suitable for worm gears. CT analysis showed that all parts of worm gear were distributed with fine pores and some coarse pores were distributed around the central hole of worm gear. The yield strength and tensile strength were 220 MPa, 285 MPa, and the elongation rate was 8%. Vickers hardness is 82 HV.

• The Korean journal of sports medicine
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• v.36 no.4
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• pp.214-220
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• 2018

Purpose: The purpose of this research is to study changes in pituitary hormone in anterior lobe and thyroid hormone before, after, and during recovery time in severe 100 km ultramarathon. Methods: Healthy middle-aged runners (age, $52.0{\pm}4.8$ years) participated in the test. Grade exercise test is done, and then blood is taken from those participants before and after completing 100 km ultramarathon at the intervals of 24 hours (1 day), 72 hours (3 days), and 120 hours (5 days) to analyze their luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and free thyroxine (Free T4). Results: For LH, it decreased more significantly at 100 km than pre-race. However, after 1 day result increased more than that of 100 km. At 3 days, it was significantly higher than pre-race and 100 km, recovering at 5 days. In terms of FSH, it decreased at 100 km, 1 day, and 3 days more than pre-race but recovered at 5 days. TSH was higher at 1 day and 5 days compared to pre-race. T3 was only higher at 100 km than pre-race. T4 was higher till 5 days at 100 km than pre-race. Free T4 increased more significantly at 100 km than pre-race. Conclusion: In terms of severe long distance running, LH and FSH which belong to hormone from anterior lobe as well as T3, T4, and Free T4 which belong to thyroid hormone showed their variation within the standard range. However, TSH showed abnormal increase from enhanced concentration of blood after marathon becoming hyper-activation even during the recovery period.

• Safety and Health at Work
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• v.12 no.2
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• pp.147-153
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• 2021

Background: In this study, the association of work and demographic characteristics with different traffic offenses committed by food delivery riders in Greece was examined. Previous research has identified various factors related to risky driving however, there is a need for exploring the complex interrelationship of work-related factors underlying risky driving behavior. Materials and Methods: A 2-items uestionnaire was used exploring delivery riders demographic characteristics, terms of employment, issues of concern during work and type of traffic offenses committed. In total, uestionnaires were analyzed using logistic regression in order to identify characteristics independently associated with serious traffic offenses, namely, red-light running and helmet non-use. Results: The analysis showed that: (i) typical health and safety measures had no effect on serious traffic offenses, (ii) young age was related to both offenses however (iii) different sets of work conditions were associated with reports of red-light running (i.e. low work experience, use of personal vehicle for work, and payment by hour) and helmet non-use respectively (i.e. intense work pace, high tip income per day and low concern about vehicle condition). Conclusion: The above findings provide evidence that serious traffic offenses are manifestations of underlying conflict experienced by the riders between safety and various performance criteria. Each one of the two offenses is related to different rider profiles aiming to satisfy different goals, namely, those mainly trying to maximize profit non-helmet users and those, mostly inexperienced ones, trying to cope with work pressure red light runners. Potential regulatory measures to alleviate risky practices are discussed.

• Korean Journal of Exercise Nutrition
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• v.25 no.3
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• pp.16-22
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• 2021

[Purpose] Exercise-associated hyponatremia (EAH) is a well-known condition among endurance athletes at low altitudes. The incidence of EAH during ultramarathons at high altitudes warrants further investigation. This prospective observational study was conducted on the participants of the Leadville Trail 100 run, a 161-km race held at a high altitude (2,800 m-3,840 m). [Methods] Venous blood samples were collected before and immediately after the race. The participants completed an electronic survey after the race. Our main outcome measure was the post-race serum sodium ([Na⁺]) level. [Results] Of the 672 athletes who started the race, 351 (52%) successfully completed the event within the 30-hour cut-off. Post-race blood samples were collected from 84 runners (66 finishers). Both pre- and post-race blood samples were collected from 37 participants. Twenty percent of the post-race participants had EAH. Only one post-race participant had a [Na⁺] level of <130 mmol/L. All participants with EAH were asymptomatic. One participant had an abnormal pre-race [Na⁺] level (134 mmol/L). Female participants had a significantly higher rate of EAH than male participants (40% vs. 16%; p=0.039). Age, body mass index, weight changes, race completion status, nonsteroidal anti-inflammatory drug use, and urine specific gravity were not associated with the development of EAH. Lower postrace [Na⁺] levels were associated with higher serum creatine kinase values (R²=0.1, p<0.005). [Conclusion] High altitude (3,840 m peak) does not appear to enhance the incidence of EAH after an ultramarathon footrace. This suggests that ambient temperature (low temperatures reduce risk), sex (female predilection), endurance running, and overhydration are more prominent risk factors for EAH than high altitude.

• Tribology and Lubricants
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• v.39 no.2
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• pp.81-85
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• 2023

This study presents an experimental investigation of the effects of surface roughness on gas foil thrust bearing (GFTB) performance. A high-speed motor with the maximum speed of 80 krpm rotates a thrust runner and a pneumatic cylinder applies static loads to the test GFTB. When the motor speed increases and reaches a specific speed at which a hydrodynamic film pressure generated within the gap between the thrust runner and test GFTB is enough to support the applied static load, the thrust runner lifts off from the test GFTB and the friction mechanism changes from the boundary lubrication to the hydrodynamic lubrication. The experiment shows a series of lift-off test and load-carrying capacity test for two thrust runners with different surface roughnesses. For a constant static load of 15 N, thrust runner A with its lower surface roughness exhibits a higher start-up torque but lower lift-off torque than thrust runner B with a higher surface roughness. The load capacity test at a rotor speed of 60 krpm reveals that runner A results in a higher maximum load capacity than runner B. Runner A also shows a lower drag torque, friction coefficient, and bearing temperature than runner B at constant static loads. The results imply that maintaining a consistent surface roughness for a thrust runner may improve its static GFTB performance.