• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.480-480
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• 2008

Vacuum circuit breaker(VCB) is now emerging as an alternative of gas circuit breaker(GCB) which uses SF6 gas as insulating material whose dielectric strength is outstanding. But we have to reduce SF6 gas because SF6 gas is one of greenhouse gas and efforts to reduce greenhouse gas are now trend of the world. Therefore, we can say VCB is the optimal alternative of GCB because vacuum is environmentally friendly. The vacuum interrupter is the core part of VCB to interrupt arcing current. There are mainly two methods to extinguish arc. One is radial magnetic field (RMF) method and the other is axial magnetic field (AMF) method. We deals with RMF method in this paper. Compared with AMP, RMF arc quenching method has different principle to extinguish arc. In case of RMF method, pinch effect is much larger than AMF method. Because of pinch effect RMF type contact electrodes have the single large spot which is severly damaged and melted while AMF type contact electrodes have small and multiple spots which are slightly damaged and melted. To prevent contact electrode being damaged and melted from high temperature-arc, RMF method uses Lorentz force to move arc. In this paper we calculated and compared the arc driving force of two cases and we analyzed the force acting on each part of arc by means of commercial finite element method software Maxwell 3D. They have 3petals and we considered two cases. One is the case when fixed(upper) and movable(lower) contacts are in mirror arrangement (Case 1). The other is the case when one of two contacts (movable contact) is revolved at maximum angle as possible as it can be (Case 2). And at each case above, we analyzed arc driving force at two positions, position 1 is the closest to the center of contact and position 2 is near the edge of petal on fixed contact. As a result we could find that Case 2 generated stronger arc driving force than Case 1 at position 1. But at position 2 Case 1 generated stronger arc driving force than Case 2. This simulation method can contribute to optimizing spiral-type electrode designs in a view of arc driving force.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.350-356
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• 2018

The contact force, which is the dynamic interaction between the pantograph and the catenary, is an important indicator for evaluating the current collecting quality, which is a stable power supply characteristic to the vehicle. In this study, dynamic contact force characteristics of pantograph of HEMU-430X vehicle, which is a power-distributed high-speed train test vehicle, were analyzed according to the catenary tension and compared with the analytical results using the pantograph-catenary interaction model. As a result of comparing the test results with the analytical results, it was confirmed that the average contact force and the standard deviation of the contact force, which are the main dynamic contact force characteristics, coincide relatively well. Using the analytical model, the relationship between the catenary tension and the contact force is presented according to the vehicle speed, and the optimal catenary tension for each operation speed is presented and compared with the international standard. As a result, it was found that the results obtained from the analysis are comparable to those recommended by international standards.

• Journal of Food Hygiene and Safety
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• v.20 no.1
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• pp.13-17
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• 2005

The purpose of the present study was to investigate differences in the sensitizing potential of Rhus Veniciflua(Rhus-II), when tested by the guinea pig maximization test(GPMT) and Freund's complete adjuvant test(FCAT) with an identical, intradermal induction concentration. A new grading classification of the sensitization potential is proposed. The GPMT was conducted according to OECD guideline $\#406$, using a multiple-dose design and test results were analysed with logistic regression analysis. During the induction stage, we injected intradermally each three site 0.1 ml(l mg/animal) test material, 0.1 ml complete Freund's adjuvant and 0.lml the test agent emulsified in the adjuvant. 7 days later, we induced weak sensitization with $10\%$ sodium lauryl sulfate(SLS) and applide 1ml(l0mg/animal) test agent topically on the same site and made a tight occlusion. 14 days later we challenged with 1 ml(l 0mg/animal) of test material on the flank and observed ant 24 hours and 48 hours later. The results were also observed $0\%$ at 24 hours challenge. The results observed 48 hours after challenge were the identical. These data indicated that, although Rhus-II is a no contact allergen. It was reported that the skin sensitization by Rhus-II was not detected the skin sensitization in the guinea pig maximization test (GPMT). Consequently, it was confirmed that Rhus-II had no contact allergic sensitization in guinea pig maximization test.

• Journal of Families and Better Life
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• v.24 no.5 s.83
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• pp.53-68
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• 2006

This study examines Korean and American undergraduate students' intimacy toward the grandmother and their attitudes toward the elderly and aging. The study also identifies the variances that influence undergraduate students' attitudes. The subjects were 397 Korean and 364 America undergraduates. Statistical analysis was conducted to examine frequency, percentage, meat standard deviation, Cronbach's ${\alpha}$, t-test, Duncan test, ANOVA, and stepwise multiple regression. The results of this study were as follows; 1) Both Korean and American undergraduates' attitudes were mid-range, but their intimacy level toward their grandmother was high. 2) The Korean undergraduates' intimacy level differed significantly according to sex and religion, and it showed a significant correlation with attitudes toward the elderly and aging traits, when the student had lived with and had frequent contact with the grandmother. The American undergraduates' intimacy level, however, was significantly different according to the presence of the grandmother. There was also had a significant correlation with the undergraduate students' attitudes toward the elderly and aging traits, frequency of contact with the grandmother and year. 3) The variables that affect the Korean undergraduates' intimacy level toward the grandmother were attitude, cohabitation with her, gender, frequency of contact with the grandmother, and religion, which explained about 21% of total variance. Attitudes toward the elderly and aging traits were very important variables for Korean undergraduates' intimacy with their grandmother. The American undergraduates' intimacy was affected by the variables of attitude, frequency of contact with the grandmother, year, and the presence of the grandmother, which explained about 19% of the total variance. Attitude toward the elderly and aging traits were the most important variables for American undergraduates' intimacy with their grandmother.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.245-252
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• 2001

This study was carried out to investigate the effect of three factors(dynamic load, inflation pressure and multiple passes of the tire) on the contact pressure and the soil stresses under the tire. A series of soil bin experiment was conducted with a 6.00R14 radial-ply tire for sandy loam soil. Tire contact pressure at soil surface and soil stresses at 10cm and 20cm soil depth were measured for the three levels of dynamic load(1.17kN, 2.35kN and 3.53kN), for the three levels of tire inflation pressure(103.42kPa, 206.84kPa and 413.69kPa), and for five different number of passes(1, 2, 3, 4 and 5 pass). The following results were drawn from this study 1) As dynamic load, inflation pressure and number of passes of the tire increased, tire contact pressure at soil surface and soil stresses at 10cm and 20cm soil depth increased accordingly. Thus increased in dynamic load, inflation pressure and number of passes of the tire would increase soil compaction. 2) The effect of three different factors, or dynamic load, inflation pressure and number of passes of the tire, decreased as the soil depth increase. Consequently, it was found that the soil compaction at a shallow depth in soil is larger than that at deep place in soil. 3) The increase of dynamic load and number of passes increased soil stress exponentially, but the increase of inflation pressure increased soil stress linearly. The effect of tire inflation pressure on soil stress was relatively less than that of the dynamic load. Therefore, it was concluded that dynamic load is more important factor affecting soil compaction in comparison to the inflation pressure of tire.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.215-225
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• 2018

The purpose of this is to understand critical roles of contact employees' organization citizenship behaviors (OCBs) in customers' evaluation of service quality. This paper examines the relationship of employees' OCBs with job satisfaction, trust in manager, and customer's perceived service quality in deluxe hotel. The empirical results show that contact employee' job satisfaction and trust in manager are significantly related to OCB and that their active engagement in OCB has a positive relationship with the perception of service quality. Although there exists a significant common method factor possibly influencing the strength of the relationship, this factor did not affect the overall pattern of significant relationship. Another notable finding indicates that, unlike a global OCB measure, path estimates in the relationship of job satisfaction and trust to OCB variable are not similar and suggests that the multiple facets of OCBs provide more detailed information than a global OCB.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.319-341
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• 2016

Objective:This research analyzed the lower-limb motion in kinetic and kinematic way while walking on various terrains to develop Foot-Ground Contact Detection (FGCD) algorithm using the Inertial Measurement Unit (IMU). Background: To estimate the location of human in GPS-denied environments, it is well known that the lower-limb kinematics based on IMU sensors, and pressure insoles are very useful. IMU is mainly used to solve the lower-limb kinematics, and pressure insole are mainly used to detect the foot-ground contacts in stance phase. However, the use of multiple sensors are not desirable in most cases. Therefore, only IMU based FGCD can be an efficient method. Method: Orientation and acceleration of lower-limb of 10 participants were measured using IMU while walking on flat ground, ascending and descending slope and stairs. And the inertial information showing significant changes at the Heel strike (HS), Full contact (FC), Heel off (HO) and Toe off (TO) was analyzed. Results: The results confirm that pitch angle, rate of pitch angle of foot and shank, and acceleration in x, z directions of the foot are useful in detecting the four different contacts in five different walking terrain. Conclusion: IMU based FGCD Algorithm considering all walking terrain possible in daily life was successfully developed based on all IMU output signals showing significant changes at the four steps of stance phase. Application: The information of the contact between foot and ground can be used for solving lower-limb kinematics to estimating an individual's location and walking speed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.11-19
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• 2014

Reliability of the novel automatic system capable of measuring both St$\ddot{o}$ckigt sizing degree and contact angle at a time was evaluated through the calculation of its repeatability and reproducibility based on TAPPI Standard Method T 1200. As the basis weight of paper specimen increased, the repeatability and reproducibility of the automatic system became more improved than those from Hercules sizing test and contact angle test designated on TAPPI Standard Method T 530 and T 558. The more improved repeatability and reproducibility implies that a single tester can obtain the similar results under similar test conditions in spite of repetitive testing using the automatic system, and likewise that multiple testers can respectively reproduce similar data without big variation from the same paper specimen using the automatic system. In conclusion, this study is greatly meaningful in having developed the world's first automatic system to measure both St$\ddot{o}$ckigt sizing degree and contact angle simultaneously with excellent repeatability and reproducibility.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.377-391
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• 2015

Inter-dental arch discrepancy between maxilla and mandible could cause three dimensional occlusal problems, and collapse of occlusal plane, multiple teeth loss and decrease of masticatory efficiency could be observed in patient having unstable occlusal contact. Patient showing posterior bite collapse, unstable occlusal contact and improper anterior guidance should be treated to recover stable centric occlusion, occlusal contact, and anterior guidance in conjunction between prosthodontics and orthodontic treatment. This clinical report describes the favorable results of orthodontic and prosthodontics rehabilitation of patient with above mentioned problems.

• Journal of Digital Convergence
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• v.16 no.11
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• pp.373-381
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• 2018

The purpose of this study is to investigate the effect of multicultural contact experience and ethnocultural empathy on multicultural acceptance in nursing students. Participants were nursing students in 3 universities in C city and data were collected from November 15 to December 20, 2017. Data were analyzed by t-test, one-way ANOVA, Pearson's correlation, multiple regression analysis using SPSS Win 23.0. It was found that: (a) multicultural acceptability had a positive correlation with emotional empathy(r=.56, <.001), cognitive empathy(r=.40, <.001), and experience of multicultural contact(r=.16, p=.040; (b) factors influencing multicultural acceptance were emotional empathy and cognitive empathy with 37.3% explanatory power. This study shows that emotional and cognitive empathy have positive effect on multicultural acceptance. This result may be useful in developing new strategies for enhancing multicultural acceptance.