• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1508-1511
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• 1996

In the fields of the optics, precise machine, semiconducting processing, the micro-positioning actuators are required for the control of position in submicron range. In this study, dielectric properties of 0.5PNN-(0.5-x)PZN-xPZT system ceramics with different PZT mole ratio were investigated. As the amount of PZT incerases, curie temperature was increased. The maximum of dielectric and piezoelectric constant was shown at 0.3 mole ratio of PZT amount. As a results, we have found that the structrue of ceramics with PZT 0.3 mole was morphotropic phase boundary.

• Proceedings of the KOR-KST Conference
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• 2003.02a
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• pp.97-116
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• 2003

본 연구에서는, 기존의 악세스빌리티지표가 다양한 효과를 고려하지 못한다는 점에 착안하여, 새로운 악세스빌리티지표를 개발하였다. 노드의 중심성을 나타내는 중심도함수에 근거해, 네트워크 악세스빌리티지표(Netword Accessibility Index)와 철도이용자의 효용최적화의 관점으로부터 유틸리티 악세스빌리지표(Utility Accessibility Index)를 제안하였다. 그리고, 본 연구에서 제안한 지표가 종래의 지표보다 철도건설에 따른 편익치를 보다 정확하게 나타내는지를, 서울시지하철5호선과 오사카JR동서선의 개업효과를 계측함으로써 검증하였다. JR동서선의 경우, 중심지까지의 기존노선이 기설되어 있어 소요시간 단축효과보다 수송력증강과 철도네트워크의 확충에 의한 효과가 보다 크게 반영되었다. 또한, 위에서 산출한 편익치를 환수하기위한 기초데이타로 활용해, 고정자산세와 토지양도 소득세를 적용해 환원액을 산출하였다. 그리고, 이렇게 구한 환원액을 특정재원화시켜, 지하철5호선과 JR동서선의 사업주체에 보조해, 사업자의 채산성에 어떠한 영향을 미치는지, 신선건설비를 부담하는 해당 지자체의 비용부담을 어느정도 경감시킬 수 있는지를 정량적으로 밝혔다.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.54-59
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• 2004

In this paper probabilistic fracture mechanics(PFM) approach is employed to evaluate the integrity of CANDU Zr-2.5Nb pressure tubes. Modified failure assessment diagram(Jr-FAD), plastic collapse, and critical crack length(CCL) approach are used for evaluating failure probability of the tubes. Jr-FAD was extended from the Kr-FAD because fracture of pressure tubes occurs in brittle manner due to hydrogen embrittlement of material by deuterium fluence. For developing the probabilistic integrity evaluation module, AECL procedures and fracture toughness parameters of EPRI were used.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.63-76
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• 2009

On the basis of a Stochastic Frontier Approach (SFA), this paper analyses revenue efficiencies for the same sample of Korean and Japanese railways in the papers which analyze cost efficiencies using a generalized translog functional form. The paper also compares the results of revenue efficiencies with cost efficiencies and evaluates the effects of managerial autonomy and privatization on the firm-specific efficiencies. The results show that the average estimate of revenue inefficiency is 7.02% when the term of inefficiency is assumed to be distributed as a half-normal and 6.98% as a exponential for the total sample. Also, standardized inefficiencies in revenues (7.5%) are greater than those in costs (2.1%). JR East and JR West are found to be most efficient on the revenue side and on the cost side respectively while JNR and JR Kyushu are worst efficient on the both sides. Finally, the correlations between efficiencies in revenues and costs also between efficiencies and privatization are positively correlated. The results suggest that the most independent companies, with increased managerial autonomy via privatization, are the most efficient in both revenues and costs.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.132-134
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• 1994

In this study, the gnenral purpose type Linear Pulse Motor(LPM) and measurement system were desisted. And this LPM is tested by the experimental apparatus to write up a operating pattern parameter.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.1-6
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• 2004

In the course of taxonomical studies of oribatid mites, two genera, Acrotocepheus Aoki, 1965 and Humerobates Sellnick, 1928, and their species, A. gracilis Aoki, 1965 and H. flechtmanni Perez-Inigo ＆ Perez-Inigo Jr, 1993, are recorded for the first time in Korea.

• Nuclear industry
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• v.21 no.7 s.221
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• pp.42-45
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• 2001

• 에너지협의회보
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• s.33
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• pp.9-13
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• 1995

• 해운
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• no.3 s.26
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• pp.23-27
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• 2006

• KOREAN POULTRY JOURNAL
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• v.6 no.4 s.54
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• pp.110-111
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• 1974