• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1190-1199
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• 2020

The purpose of this study is to analyze the variables affecting the effective stroke in the swing performed through 12 weeks of training for golf beginners, and to provide basic data on the effective stroke factors for the golf beginners to settle on the fairway. Twenty subjects were participate in the study (age: 21.35±1.69 yrs, height: 176.75±7.99 cm, weight: 70.70±9.76 kg). All subjects were subjected to a 12-week golf training, and trackman 4 was used in the 12th week to calculate variables affecting the effective stroke during a golf swing. Trackman data was divided into club-variables and ball-variables, and a binary logistic regression analysis was performed to find out the variables affecting effective strokes. In club-variables, high dynamic loft and low face angles were found in effective stroke, and in ball-variables, fast ball speed, large smash factor, high launch angle, and many spin rates were also found in effective stroke. As a result of the binary logistic regression analysis of club-variables, the probability of an effective stroke increased as the club speed and dynamic loft increased, and the probability of an effective stroke decreased as the face angle increased. The influence of effective stroke in the club-variables was in the order of dynamic loft, face angle, and club speed. In the ball-variable, the probability of an effective stroke increased when the lunch angle increased, and the probability of an effective stroke decreased as the lunch direction increased. As a condition to increase the probability of effective stroke based on the results, it is necessary to increase the club speed through high dynamic loft and low face angle during swing through continuous practice. Through this, the probability of effective stroke through increasing the launch angle and decreasing the launch direction will increase.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.2
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• pp.149-179
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• 2011

Statistics of aviation accident in Korea show that safety level of training flights is high. However, more than 80% of aviation accidents happen owing to human factors. And because most reasons of them are concerned with pilot error, it is very important for student pilots who will transport a lot of passengers to develop the knowledge of safety and abilities of risk management for preventing accidents. In this study, in order to investigate the Human Factors which affect safety in training student pilots for flight, verified the correlationbetween experiences of accident, the differences according to the experience level of training flight and the differences between college student pilots and ordinary student pilots on the basis of human factors that composes the SHELL models. For the study, Using SPSS 17.0, conducted Correlation Analysis, Analysis of Variance(ANOVA) and t-test. To sum up the result of this study, student pilot's ability and equipment in the cockpit are the important factors for safety when pilots are training flight. Also the analysis of the differences between human factors according to the characters of student pilots' groups shows that college student pilots are affected by immanent factors and organizational cultures. So far, there haven't been any accidents which is related with human casualties when training at the ATO(Approved Training Organization). But accidents can occur at any time and anywhere. Especially the human factors which comprises most of aviation accident have a wide reach and are impossible to be eliminated, therefore, it is best to minimize them. Because ATO is the starting point to lead the aviation industry of Korea, we will have to be aware of problems and improve education/training of human factors.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.33-38
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• 2021

Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.

• Journal of Intelligence and Information Systems
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• v.28 no.3
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• pp.105-117
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• 2022

This study analyzes the effects between stock returns and interest rate spread, difference between long-term and short-term interest rate through the polynomial linear regression analysis. The existing research concentrated on the business forecast through the interest rate spread focusing on the US market. The previous studies verified the interest rate spread based on the leading indicators of business forecast by moderating the period of long-term/short-term interest rates and analyzing the degree of leading. After the 7th reform of composite indices of business indicators in Korea of 2006, the interest rate spread was included in the items of composing the business leading indicators, which is utilized till today. Nevertheless, there are a few research on stock returns of each industry and interest rate spread in domestic stock market. Therefore, this study analyzed the stock returns of each industry and interest rate spread targeting Korean stock market. This study selected the long-term/short-term interest rates with high causality through the regression analysis, and then understood the correlations with each leading period and industry. To overcome the limitation of the simple linear regression analysis, polynomial linear regression analysis is used, which raised explanatory power. As a result, the high causality was verified when using differences between returns of corporate bond(AA-) without guarantee for three years by leading six months and call rate returns as interest rate spread. In addition, analyzing the stock returns of each industry, the relation between the relevant interest rate spread and returns of the automobile industry was the closest. This study is significant in the aspect of verifying the causality of interest rate spread, business forecast, and stock returns in Korea. Even though it could be limited to forecast the stock price by using only the interest rate spread, it would be working as a strong factor when it is properly utilized with other various factors.