• 수산해양교육연구
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• 제25권4호
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• pp.878-890
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• 2013

The purpose of this study is to apply the PEOE class model that can enhance students' scientific creative problem-solving ability and self-directed learning ability in the middle school science subject and analyze the effects of it on students' long- and short-term retention, scientific creative problem-solving ability, and self-directed learning characteristics. And the paper has gained the following results: First, according to the result of analysis through the pre-test, post-test, and delay test to examine the effects of PEOE-based class on learners' long- and short-term retention, it is found to be statistically significant in the significant level of .05. In other words, the class using PEOE influences learners' short-term retention significantly, but it is even more effective in transmitting the concept that students acquire into their long-term memory. Second, according to the result of analysis through the pre-test and post-test to examine the effects of PEOE-based class on learners' scientific creative problem-solving ability, it is found to be statistically significant in the significant level of .05 in general. However, 'elaboration' and 'originality', the subfactors of scientific creative problem-solving ability, do not indicate significant effects. Third, according to the result of analysis through the pre-test and post-test to examine the effects of PEOE-based class on learners' self-directed learning characteristics, it is found to be statistically significant in the significant level of .05 as a whole. However, 'openness' and 'future-oriented self-understanding', the subfactors of self-directed learning characteristics, do not exert significant effects. Based on the above study results, it can be concluded that PEOE-based class is more effective for learners' academic achievement in science, scientific creative problem-solving ability, and self-directed learning characteristics than lecture-method instruction regarding the middle school science unit of 'The Properties of Air and Weather Change'.

• 한국운동역학회지
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• 제17권3호
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• pp.51-60
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• 2007

The purpose of this study was to kinematically analyze the differences between short(2.17 m) and long(10.94 m) putting stroke motions. Thirteen male professional golfers were participated in this study. Experiment was conducted on the artificial grass mat in the gymnasium. Kinematic data were collected by the 60 Hz Kwon3D motion analysis system. Differences were compared by SPSS paired t-test and one-way ANOVA. Duncan was used for post-hoc test and a=.05. The results were as follows: 1. Ground projected trajectory of the putter head were statistically straight during both short and long putts. 2. There was no consistent alignment tendency among shoulder, hip, and stance alignments. However stance alignment was consistent between short and long putts. Thus it is assumed that professional golfers align their body based on their stance alignment. 3. During putting, shoulder rotated not only up and down but also right and left. 4. Left and right elbow distance was maintained during all phases of the putts for both short and long putts. 5. Inter foot distance of long putting was longer than that of short putting.

• PNF and Movement
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• 제18권1호
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• pp.127-132
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• 2020

Purpose: This study aimed to investigate the impact of resistance on the muscle activities of the long and short heads of the biceps brachii, according to the elbow angle in supination, and the difference in muscle activity between the long and the short heads. Methods: This study was conducted with 22 men in their 20s who voluntarily agreed to participate. With the glenohumeral joint neutral in a position of supination, the elbow angle was randomly moved to 0°, 30°, 60°, and 90°. Using an 8-channel surface EMG while the participants held a 2-kg. dumbbell, the muscle activities of the long and the short heads of the biceps brachii were measured. The measured data were statistically processed using SPSS for Windows 12.0. For the activities of the short and the long heads according to the angle, a one-way ANOVA was conducted, and subsequently, to check the results of an analysis of the difference between groups, an LSD post-hoc test was conducted. An independent t-test was used to compare the activities of the long head and the short head according to the angles. Results: The analysis of the impact of the load of the dumbbell at each elbow angle on the muscle activities of the long and short heads of the biceps brachii revealed significant differences in both heads (p < 0.05). The result of the post-hoc analysis showed significant differences in both heads at angles between 0° and 30°, between 0° and 60°, and between 0° and 90°. Analysis of the impact of the load of the dumbbell in supination on the muscle activities of the long and short heads showed a significant difference at the angle between 0° and 30° (p < 0.05). Conclusion: The long head of the biceps brachii mainly acts in supination; however, in supination at elbow-bending angles of 60° and 90°, there was no difference in muscle activity between the short head and the long head.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.700-702
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• 2005

The most electrical apparatus should be able to withstand short-time current and peak current during a specified short time until circuit breakers have interrupted fault current. It defines the short-time withstand ability of electric a apparatus to be remain for a time interval under high fault current conditions. It is specified by both dynamic ability and thermal capability. KERI(Korea Electrotechlology Research Institute) recently constructed the new short-time current and low voltage short circuit testing facilities. This paper shows short- circuit calculation of transformer and describes high current measuring system, and evaluate the result of short-time withstand test used in $3{\phi}$ 90MVA short-time current testing facilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.237-239
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• 2006

The residual flux(${\psi}_r$) in transformer's iron cores cause the distortion of short-circuit current occasionally. And some considerable distortion effect on the validation of test results. To prevent this situation, there needs some suitable control of residual flux through the pretest. This paper deals with the how to control the residual flux in pretest and the comparison between the two test results which were obtained by different test method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.445-448
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• 2003

Polymer concrete using wastes PET recycled resin that is, in general, more excellent mechanical properties than portland cement concrete. A lot of works are carried out about short-term properties of polymer concrete, however, little work has done to define their long-term properties, that is, sustain load such as creep. In this study will show the data that can long-term behavior of polymer concrete by short term creep test of polymer concrete that was affect to the temperature and the time to predict to long-term creep behavior. Then prediction equation was similar tendency that was comparing to short-term creep test and long-term creep test.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권1호
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• pp.27-32
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• 2005

This study presents an analysis technique that can consider all variables which are needed in the design of short circuit current capability of electrical contacts. Required variables in the design are material of contact, contacting area, applied force, asperity of surface, current and so on. Short circuit current capability test was carried out for the interrelation of design variables and the verification of analysis technique. Temperature rise equation of the contacts was obtained from the test results, and also, a standard that is criterion of the occurrence availability of melting or spot of contact surface from test results was established.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권12호
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• pp.578-583
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• 2002

For ac PDP, the lifetime should be guaranted over, 30000 hours. The lifetime is correlated with the deterioration characteristics for the weakest element in ac PDP. However, the short-term deterioration test method of the at PDP has not well developed. In this paper, a short term deterioration test method of a given element in the ac PDP is proposed. By this method, MgO deterioration characteristics are investigated. The deterioration rate is decreased with MgO thickness but it was almost saturated over 5000$\AA$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1446-1448
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• 2002

The short-time permissible temperature of an overhead distribution line conductor is determined by the softening characteristics of ACSR-OC, ACSR AW/OC 160, typical conductors employed in the overhead distribution line. Transient heat transfer equation and Newton's cooling law were applied to analyze the heating and cooling effects of the insulating conductors, respectively, and the error of co-relation was calibrated after simulating the softening test to assess the short-time characteristic of the insulating conductor. In order to verify the softening characteristic, the conductors were tested with heat cycle. The test was totally carried out 200 cycles, and 1 cycle was to heat and cool at 1.1 times permissible current of the conductor, 1.15 times for 120 minutes, respectively. After heating, the tensile strength and surface of the conductor were observed. In case of ACSR-OC, as the result of 100 hour heating test, the tensile strength of the insulator was 0.8 times the initial value. This is equivalent to the value of the conductors which are used for 10 years at sites.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.78-80
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• 2007

The residual flux in transformer's iron cores leads to a distortion of short-circuit current occasionally. And some considerable distortion may have effect on the validation of the test results. To avoid the substantial distortion, a suitable pretest is performed before the actual test. In case of applying this method there must be excessive overvoltage due to switching of an unloaded transformer and chopping of an excitation current. The purpose of this paper is estimate that the effect of the overvoltage results from this phenomenon on insulation performance of short-circuit transformer.