• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.359-363
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• 1989

Recently, it is reported that the behavior of thermal $SiO_2$ under high electric field and current condition has a major effect on MOS device degration. Furthermore, when thin oxide films are applied in practical device, the presence of oxide defects will be a serious problem. In this paper, because TDDB is the useful method to measure the effective density of defects, we stressed MOS structure that is 150 A of thermally grown $SiO_2$as a function of electric field (9-19 MV/cm), temperature ($22^{\circ}C$ - $150^{\circ}C$) and current. By examing TDDB under positive voltage, long-term oxide breakdown reliabiliy is described. From these data, breakdown wearout limitation for the oxide films can be characterized.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.125-132
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• 1993

On this study, magnetic force versus input currents is analyzed by modeling taper plunger type proportional electromagnet of ISC valve using the permernce method. And, the reliabiliy of simulation is verified by comparing the experimental values with the calaulate magnetic force. From the result of this study, it is found that the taper angles at plunger and core, the length of air gap between plunger and yoke are the prumary factors in designing taper plunget type proportional electromagnet. Magnetic force is decreased as a whole according to increasing the air gap between pluger and yoke, and vise versa. But, the magnetic force is not proportional to current, when the air gap is very small. In case of decreasing the taper angle of pluger, the stroke range of plunger where magnetic force is proportional to current becomes farther from core.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.445-450
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• 2003

This study was performed 10 develop the accelerated life test method using Weibull-IPL(Inverse Power Law) model for mechanical components. Weibull-IPL model is concerned with determining the assurance life with confidence level and the accelerated life test time From the relation of weibull distribution factors and confidence limit, the testing times on the no number of failure acceptance criteria arc determined. The mechanical components generally represent wear and fatigue characteristics as a failure mode. IPL based on the cumulative damage theory is applied effectively the mechanical components to reduce the testing time and to achieve the accelerating test conditions. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% confidence level for one test sample. According to IPL, because test time call be shorten in case increase test load test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7.

• Journal of Families and Better Life
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• v.14 no.1
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• pp.65-84
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• 1996

This study aims at the extraction of what is universally to be taught in modern Korean Families and its scalization. That is it attempts to provide the criterion by which we can determine what to teach children in the family not in society or school. For this purpose this study firstly reviews the preceeding studies on the subject. As a result of the review we postulate the hypothetical structure consisting of 12 domains. Secdndly we gather the parent's view on the topic by interviewing 192 parents of the students. On the basis of this study we can construct the questionnaire(Likert scale; 5 point) After we conduct an extensive empirical research(518 parents) in order to generalize 179 items of the worked-out questionnaire. We apply factor analsis(principal axis factoring oblique (promax) rotation) in the verfication of the validity. As the consequence we select 87 items consisting 15 factors which explain 71% of common variance. We name the 15 educational factors extracted in the scale as follows; Values & Sociality Training for basic living habits The maintenance of the culture life on the family Religious life Learning guide Economic life Patriotism Independent living Table manners The management of commodity The preservation of family unity Sex & a Frendship with the opposite sex Esteem for a traditional way of life Respect for the Old Filial piety. The reliabiliy of the scale is the cronbach a=.96 which turns out to be satisfactory.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.1
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• pp.9-16
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• 1996

A new stereo matching method for the relative orientation and the photogrammetric triangulation has been pro-posed. It matches the pairs of conjugate points to be used as pass points and tie points in digital aerial photographs instead of selecting these points with manual point transfer and measurements. Three unique steps included in the proposed matching method are as followings. The first step is searching interest points, and designating them as candidate points to be matched. The second is matching the points from the pair of images by the Cross Correlation Method in both direction(left to right direction and right to left). The third is selecting consistent pairs in the both matching directions. Computer programs based on the proposed matching method have been developed, and with digital aerial photographs which have full ground coordinate information tests were performed to know reliabiliy and positional accuracy of proposed method. Results of the tests reveal that the proposed matching method can eliminate the in-correctly matched pairs more efficiently than other matching methods, thus this can be more reliably applied to the relative orientation and the photogrammetric triangulation.