• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.81-87
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• 2017

This paper describes the dynamic behavior and enhancement of Korean high-speed trains. The tail vibration reduction method of the yaw damper installation method change, which was derived from previous research, was applied to the running test of high-speed train. In addition, the vibration reduction method for the entire vehicle was derived by a numerical method and its effect was confirmed by a running test. The improved design was applied to the double-deck high-speed train coaches and the commissioning proceeded without problems in dynamic behavior. Sensitivity analysis of the suspension parameters affecting the critical speed of Korean next-generation high-speed trains was performed and four design variables that greatly affected the critical speed were derived. These were in the order of the primary elastic joint x-directional stiffness, the secondary yaw damper series stiffness, the secondary lateral damper damping coefficient, and the carbody damper damping coefficient. By optimizing the design variables, the suspension parameter that improves the critical speed by 23.3% can be used in the commercial designs of Korean next-generation high-speed trains.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.134-141
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• 2005

Semi-Spherical Continuously Variable Transmission(SS-CVT) is the CVT which transmits power by rolling friction between dry metals, and its outstanding advantage is the ability of realizations of neutral, forward and reverse states without relying on any other devices. A spherical shaped variator transmits power and also changes gear ratio where keeping contact with a output disk. The frictional direction to transmit power and the other direction to change gear ratio are perpendicular to each other, so we can describe that two dimensional rolling friction is occurred in the contact point between the variator and the disk. Since magnitudes or relations of the two forces are completely unknown, they were analyzed by the experiments in this study. We determined the variables related with the friction phenomena by the dimensional analysis, and manufactured the SS-CVT test bench which could measure the related variables. Finally, the empirical formula for evaluating the two friction forces was proposed based on the experimental results.

• PNF and Movement
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• v.15 no.2
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• pp.141-148
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• 2017

Purpose: This study attempts to identify the effects of abdominal strength training using proprioceptive neuromuscular facilitation (PNF) on the balance ability and pain level of patients with chronic lower back pain. Methods: A total of 30 patients with chronic lower back pain were randomly divided into either experimental group I (n=10), who received abdominal strength training using PNF, experimental group II (n=10), who received abdominal strengthening training, or the control group (n=10), who received conventional physiotherapy. The interventions were applied three times a week for six weeks. We measured Berg's balance scale (BBS) in order to investigate the change in balance ability, while we measured the visible analogue scale (VAS) to determine the severity of pain. We conducted a paired t-test to compare the within-group change before and after the intervention. For the comparison of the between-group difference, we used a one-way ANOVA test. Tukey's test was used as a post hoc test. The statistical significance level was set at ${\alpha}=0.05$ for all the variables. Results: Experimental group I and experimental group II showed a significant within-group change in BBS (p<0.01). A statistically significant between-group difference was observed in terms of the change in BBS (p<0.01). According to the results of the post hoc Tukey test, experimental group I and experimental group II showed a more effective change in BBS than the control group. Experimental group I, experimental group II, and the control group all showed a significant within-group change in the VAS (p<0.01). There was a statistically significant between-group difference in terms of the change in the VAS (p<0.01). According to the results of the post hoc Tukey test, the change in the VAS was more effective in experimental group I than in experimental group II and the control group. Conclusion: In this study, the application of abdominal strength training using PNF for subjects who complained of chronic lower back pain proved effective in improving their balance ability and reducing pain. We therefore believe that this training method could be applied as a useful program for patients with chronic lower back pain.

• Korean Journal of Social Welfare
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• v.43
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• pp.246-269
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• 2000

This paper describes the results from a prevention program for low-income mothers of children under the age of 13 aiming at the positive change on parental attitudes toward their children, parenting satisfaction and attitudes toward the use of corporal punishment. The program duration was 8 weeks and consisted of two parts: parent education on understanding parent-child relationship, communication skill improvement, techniques of problem solving, non-punitive child rearing techniques; and the recognition and use of existing social support network including networking of the neighborhood resources. The pre-post test control group design was employed. The results are: the program is effective on bringing some positive changes on an three variables: parental attitudes toward their children, parenting satisfaction and attitudes toward the use of corporal punishment. Increased social support was found to have significant positive effect on the above variables except the attitudes toward corporal punishment. To decrease the risk factors as well as to increase the protective factors of child abuse, well designed parent education and social support program is recommended on every community level.

• Journal of The Korean Digital Architecture Interior Association
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• v.13 no.3
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• pp.15-23
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• 2013

As a succeeding analysis on the variables' significance to 'Quality of Life(QOL)'(Kim, Dong-Yoon, 2012a), which has a purpose of trying to enhance the intersubjectiveness by means of quantitive methods to find the factors on the QOL, this study aims at finding the time serial change in the deciding factors to deepen the related researches on the theme. Using the similar statistical methods such as multiple regression and factor analysis for "2012 Seoul Survey" this study shows two similar points and one differentia. The similarities include the fact that five subcategories of happiness have relative statistical importance in the order of (1)financial condition, (2)health condition, (3)social activities, (4)community relationship and (5)family life and the fact that the five subcategories are conceptually different from the 5 deciding factors, which means the possibility to improve the survey design. And the difference is the 5 factors such as (1) social trust - amenities, (2)cultural life, (3)social indiscrimination - hope for elevation, (4)sharing - giving and (5)community spirit which are largely different from preceding study. Although only the first two factors have statistical significance this result has a implication that they reflect the new paradigm of social capital and the essential necessity of human survival; sharing-community-culture.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.621-626
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• 2001

Microcellular foaming process was developed at MIT in 1980's to save a quantity of raw materials and improve mechanical properties. There are many process variables in appling microcellular foaming process to the conventional injection molding process. Of all process variables, part dimension control and shrinkage are the most influential on the post molded dimension. The post molding dimensional change of thermoplastic resins is important to tool designers for predicting the specific difference of molded part vs. actual mold cavity. Generally, articles injection molded are smaller in size than the cavity; hence, the term shrinkage factor is used to define the allowance a designer specifies. It is important to consider the factors that influence molded part dimension. According to ASTM Designation: D 955, shrinkage from mold dimensions of molded plastics was measured. In injection molding, the difference between the dimensions of the mold and of the molded article produced therein from a given material may vary according to the design and operation of the mold. In this paper, shrinkage data of molded plastic parts was obtained. It can be an important information for designing optimum mold system in a microcellular foaming injection molding process.

• The Journal of Korean Physical Therapy
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• v.28 no.5
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• pp.303-307
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• 2016

Purpose: This study was conducted to determine the effects of Mulligan's mobilization with movement (MWM) on changes in the talofibular interval in the sagittal plane in subjects with chronic ankle instability (CAI). Methods: Sixteen subjects with chronic ankle instability participated in this study. The talofibular intervals were measured from US images, and the weight-bearing lunge test was used to assess dorsiflexion of the ankle joint. Each dependent variable were measured on the both affected side and sound side in three trials in pre- and post-MWM. Dependent variables were examined with a two-way mixed-design analysis of variance (ANOVA). The two factors were side (sound side versus affected side) and intervention (pre- versus post-intervention). For post hoc analysis, paired t-tests were performed to compare the dependent variables. A p<0.05 was considered to indicate significance. Results: Dorsiflexion and talofibular interval differed significantly pre- and post-intervention (p<0.05). Post-hoc analysis revealed that the talofibular interval post-MWM was significantly less than that pre-MWM on the both the affected and sound side (p<0.05). The ankle dorsiflexion in the post-MWM group was significantly greater than that in the pre-MWM group on the affected side and the sound side (p<0.05). Conclusion: The Mulligan's MWM decreased the talofibular interval in subjects with CAI. These findings suggest that the MWM technique can change the position of the talus relative to the fibular in the weight bearing position.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.180-183
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• 2009

In this study, Urban Climate Simulation was performed by 3-Dimensional Urban Canopy Model. The characteristics of urban climate was analyzed combining artificial land coverage, building size, heat production from the air conditioning and topographic conditions as physical variables which affects urban climate characteristics. The results are as follows. (1)The aspects of the urban climatal change is derived to be related to the combination of the building coverage ratio, building height and shading area. (2)Whole heat generation was influenced by the convective sensible heat at the lower building height and by the artificial heat generation at the higher one over 20-story building influence to some extent of the building coverage ratio. The effect of the altitude is not more considerable than the other variables as below $1^{\circ}C$ of the air temperature.

• The Journal of Industrial Distribution & Business
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• v.9 no.6
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• pp.15-24
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• 2018

Purpose - The adjustment of one country's monetary policy can cause the macroeconomic change of other countries. Due to this, this paper attempts to analyze the impact of China's monetary policy on South Korea's exchange rate. Research design, data, and methodology - Based on the flexible-price monetary model, sets of annual time series from 1980 to 2017 are employed to perform an empirical estimation. The vector error correction model is also used to exploit the short-run relationship between both of them. Of course, the South Korea's real GDP, the China's real GDP, South Korea's interest rate, the South Korea's interest rate and the South Korea's monetary supply are treated as independent variables in this paper. Result - The long-run findings reveal that the China's money supply has a negative effect on South Korea's exchange rate. Respectively, the short-run findings depicts that the China's money supply has negative a effect on South Korea's exchange rate. Of course, other variables selected in this paper also have an effect on South Korea's exchange rate whatever positive or negative. Conclusions - As the empirical evidence shows, the China's monetary policy has a negative effect on South Korea's exchange rate whenever in the long run or in the short run.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.8
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• pp.1406-1416
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• 1997

The purpose of this study is to find out an efficient way to utilize clothes. It will be pro- environmental effort besides enhancing clothing life. The study is based on a survey of daily clothing practices. Questionnaire is distributed to female college students who are majoring clothing, textiles, and/or home economics and their parents (n=254). ANOVA, Scheffe test, 1-test and regression are pursued respectively. The main results are as follows: 1. Students, mothers and fathers possess 50.3, 49.9, 45.4 unit clothes, respectively. Mothers possess more formal suits while students possess more casual clothes than the others. The possession pattern is affected by socio-economic variables such as income and purchasing price. 2. In the unused rate of clothes, students'(10.2%) and mothers'(9.7%) rate are significantly higher than that of fathers (6.9%). The unused rate and using efficiency of clothes are affected by socio-economic variables: income and age for unused rate; age and purchasing price for using efficiency. 3. The most important reason for unused clothes is found to be design and color of the clothes. Long years of possessing and change of fashion are the next important reasons. 4. Most of respondents are highly conscious of recycling their clothes. Most of them are willing to donate their clothes to others, re·use or exchange them with the others.