• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.129-133
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• 1998

This paper deals with a characteristic of output for high frequency resonant inverter type x-ray generator in short exposure time. In the same tube-voltage, the waveform is stable in long exposure time (200msec) but more decreasing exposure time (50msec), the waveform is distorted. The ripple factor of tube-voltage waveform distorted more and more increase tube-voltage and in this case output is also unstable. High-frequency resonant inverter type X-ray generator using PSU source which introduced in resent is stable tube-voltage waveform and low ripple factor.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.601-607
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• 2002

Infiltration of rainfall causes railway embankment to be unstable and may result in failure. Basic relationship between the stability of railway embankment and rainfall introducing the partial saturation concept of ground are defined to analyze the stability of embankment by rainfall. A pressure plate test is also peformed to obtain soil-water characteristic curve of unsaturated soils. Based on this curve, the variables in the shear strength function and permeability function are also defined. These functions are used fur the numerical model for evaluation of railway embankments under rainfall. As comparing the model and case studies, the variation of shear strength, the degree of saturation and pore-water pressure for railway embankment during rainfall can be predicted and the safety factor of railway embankment can be expressed as the function of rainfall amount namely rainfall index. Therefore, the research on safety factor on railway embankment considering train speed and rainfall infiltration with the variation of rainfall intensity and rainfall duration was carried out in this paper.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.1-22
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• 2017

The purpose of this research is to analysis actual condition of promoting complex industrialization and changes after promoting, and then to classify organic farmer using cluster analysis based on delineated organic farmer's changes factors. This study also aims to investigate differences in socioeconomic characteristics and behavioral intentions among classified groups of organic farmer's changes. Data were obtained by questionnaire. From the factor analysis, four factors were derived as "Economics", "Public benefit", "Environment and philosophical values" and "Establishing management and the regional bedrock". From the cluster analysis, three cluster were derived as "group that has a positive awareness of promoting complex industry", "group that has a negative awareness of promoting complex industry" and "unstable management and a regional base". And the three classifications were significantly different in the satisfaction and behavioral intentions.

• Structural Engineering and Mechanics
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• v.3 no.3
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• pp.229-244
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• 1995

The parametric instability behaviour of a plate subjected to localized in-plane compressive or tensile periodic edge loading is studied, considering the effects of damping into the system. Different edge loading cases have been considered. Damping has been introduced in the form of proportional damping. Dynamic instability behaviour under compressive or tensile periodic edge loading shows that the instability regions are influenced by the load band width and its location on the edge. The effects of damping on the instability regions show that there is a critical value of dynamic load factor beyond which the plate becomes dynamically unstable. The critical dynamic load factor increases as damping increases. Damping generally reduces the widths of the instability regions.

• The Journal of Economics, Marketing and Management
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• v.7 no.3
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• pp.29-43
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• 2019

Research Purpose - The purpose of this study was to investigate marketing stimulation and impulsive buying of Internet shopping mall. Research Question - Despite these unstable factors, the Internet shopping mall market has become more popular than traditional distribution channels such as department stores and discount stores due to the increase in the number of Internet users, a gradual increase in the consumption of high-priced items. Research Method - The data were collected from 301 women living in Seoul, Gyeonggi, Gwangju, Daegu, and Gyeongnam province in Korea on May 2018. Statistical methods used in the study were frequency, F-test, Duncan test, factor analysis, Cronbach's α, correlation coefficient, and multiple regression. Result - All The reliability of these questions is Cronbach's α =. 775. Factor 5, which is 12.367 % explanatory power, is said to consist of three questions: price, discount bag, and no-carrying; thus, the reliability of the question is Cronbachs' α. The ratio of the five factors in body random cases was 66.096 %, and the reliability of the questions was higher than. 770 as a result of the reliability analysis.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.63-76
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• 2009

A study on the interference effects of overlapping tandem rotors in forward flight is conducted using the time-marching free-wake panel method which adopts field velocity boundary integral formulation. The conventional boundary integral formulation is numerically unstable for the cases when the blade and the wake are in close proximity to each other. In order to avoid this problem, this study applies the field velocity method and modifies the boundary integration formulation. The improved method is used for the parametric study on the advance ratio and the distance between the rotors. These are the parameters that most affect the interference of the tandem rotor in forward flight. Comparison of the aerodynamic performance shows that the horizontal distance between the rotors negligibly influences the overlap-induced power factor for high advance ratio. In addition, it shows that the overlap-induced power factor is inversely proportional to the squared vertical distance between the rotors, and that the overlap-induced power factor increases to a certain extent and decrease back as the advance ratio increases.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.174-181
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• 2005

In order to investigate the behavior of fatigue crack growth of SiC-particulate- reinforced Al-Si alloy composites, fatigue tests using single edge notched tension(SENT) specimens were performed. Composite materials were manufactured by using both permanent die casting and extrusion processes with different volume fractions of $10\%\;and\;20\%$. $SiC_p-reinfurced$ Al-Si composites showed the increased levels of threshold stress intensity factor range, ${\Delta}K_{th}$, for the increased volume fractions of SiC particles, which implies the increased fatigue crack growth resistance at the threshold or low ${\Delta}K$ levels, compared to the unreinforced Al-Si alloy. In the Paris region, however, the composites showed the increased rate of crack growth resulting in the unfavorable effects on the fatigue crack growth resistance. Critical stress intensity factor range at unstable crack growth leading to final fracture decreased as the volume fraction of SiC particle increased, because of the reduced fracture toughness of the composites. Extruded materials showed higher threshold and critical values than the cast materials.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.215-223
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• 2021

Purpose: Distal radius fractures in youth are treated conservatively in most cases, but there are some cases of redisplacement in the follow-up period after cast immobilization, even after complete reduction. This study examined the risk factors of redisplacement in reduced unstable distal radius fractures. Materials and Methods: From February 2011 to June 2018, 44 unstable distal radius fractures were managed with a closed reduction and cast immobilization. The patients were aged between 6 and 14 years. The cases of redisplacement were analyzed with the fracture characteristics (fracture obliquity, fracture level ratio, ulnar fracture combined), cast qualities (gap index, cast index, 3 point index, and radius-2nd metacarpal angle) and host factors (age, sex). Results: The mean angulation in the union was 9.2° (0°-32.8°). In the categorical grouping 29 cases were within 10° angulation, and 15 cases were more than 10°. No significant differences in the factors of the cast indices or host factors were noted. The meaningful factor was the fracture level calculated by the relative width of the fracture site divided by the sum of width of diaphysis and epiphysis (p=0.001) and combined ulnar fracture (p=0.019). Conclusion: Unstable distal radius fractures should be treated with more stubborn guidelines lest the fracture loses its anatomical alignment. In particular, in patients with less remodeling power, operative treatment would secure a better result if the fracture occurs in a more proximal location.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.217-226
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• 2024

This study is a descriptive research study to figure out the effect of unstable an adult attachment, self-mercy and emotional recognition clarity on interpersonal skills targeting nursing freshman. From 27th of March 2023 to 7th of April 2023, data gathered from the nursing freshman of university in J city, G province were analyzed. Using IBM SPSS/25, the data was analyzed descriptive statistic t-test, ANOVA and multiple correlation analysis. Interpersonal skills have negative correlation with unstable adults attachment(r=-.19, p=.005), and also have positive correlation with self-mercy (r=.38, p<.001) and emotional recognition clarity (r=.28, p<.001). Using hierarchical multiple regression analysis of factors that effects on interpersonal skills of survey subjects, self-mercy was the factor predict one's interpersonal skills the most, extroverted, mixed and emotional recognition clarity in order. The higher self- mercy and emotional recognition clarity are, the bigger influences interpersonal skills have and 24.5% of explanatory power. For nursing school students, interpersonal skills was one of the essential qualities so various methods to improve their interpersonal skills should be figured out.

• Journal of Environmental Science International
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• v.18 no.8
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• pp.857-865
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• 2009

The physical properties of an atmospheric boundary layer in Wolryong, a west coastal region of Jeju, South Korea, in terms of the atmospheric stability and roughness length, is important and relevant to both engineers and scientists. The study is aiming to understand the atmospheric stability around this region and its effect on the roughness length. We calculate the Monin-Obukhov length(L) against 3 typical regions of the atmospheric condition - unstable regime (-5$-0.2{\leq}H/L{\leq}0.2$) and stable regime (0.2