• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.2
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• pp.12-17
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• 2001

In this work, the correlation between the PD Patterns and the electrical tree propagation has been investigated by use of the specimen removed from the insulation of the real 154 kV XLPE underground power cables. As a result, it could be deduced that the PD pattern regarding electrical trees depends on their type which could be classified into three different distinct groups such as branch-bush mixed. Considering the results of our investigation, if the partial discharge magnitude is only considered for the diagnosis of the cable system, it is possible to draw a wrong decision. Therefore, it is possible to propose that the time characteristics of PD pattern should be taken into account for the diagnosis of the cable system in addition to the conventional $\Phi$-q-n characteristics.

• International Journal of Reliability and Applications
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• v.2 no.1
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• pp.27-36
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• 2001

This Paper proposes a new methodology for assessing the reliability of an accident management, which Is based on the reliability physics and the scheme to generate dynamic event tree. The methodology consists of 3 main steps: screening; uncertainty propagation; and probability estimation. Sensitivity analysis is used for screening the variables of significance. Latin Hypercube sampling technique and MAAP code are used for uncertainty propagation, and the dynamic event tree generation method is used for the estimation of non-success probability of implementing an accident management strategy. This approach is applied in assessing the non-success probability of implementing a cavity flooding strategy, which is to supply water into the reactor cavity using emergency fire systems during the sequence of station blackout at the reference plant.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.435-438
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• 1991

This work is aimed to clarify the effect of only crosslinking of polyethylene on the water tree propagation and thus the crosslinking of LDPE was made by use of $Co^{60}$ $\gamma$-ray irradiation at room temperature. For this purpose, before water tree testing under same test conditions, injection molded samples were made of LDPE using CNRS laboratory model and also some of them were irradiated under different dose rate for crosslinking. Afterwards, the aged specimens were put into microscopic investigation as a mean to compare their different morphological aspects by use of SEM for the fractured surface. The SEM observation points out that the untreed region in the irradiated PE shows the densed structure whereas that in the LDPE is not closely packed. Also in the water treed region of LDPE, the density and the dimension of voids are higher than those in irradiated PE. Based on our results, it seems that the difference in the PE structure could sufficiently contribute to cause the different water tree propagation of these materials.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.9
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• pp.1060-1070
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• 1992

In this paper, characteristics of Acoustic Emission in Low Density Polyethylene were studied from tree initiation to breakdown under long-term inhomogeneous alternative electrical field. The voltage levels used were 9, 11 and 14[kV]. Especially, a newly developed automatic measuring system was used to measure time variations of AE average amplitude, AE pulse number, AE pulse distribution patterns due to polarities. The patterns wer specially the variated patterns, when tree propagated. Also, parameters for dielectric breakdown prediction, which were suggested by Okamoto, were calculated. The result was analysed by tree shapes and partial discharge activities in tree due to tree initiation and propagation.

• The Journal of Natural Sciences
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• v.18 no.1
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• pp.91-97
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• 2007

The Korean name "Bizooki" tree was named by the shape of winter bud which is like a slim bow. There are four scientific names in the tree which are Cleyera japonica Thunberg, Cleyera ochnacea DC, Sakakia ochnacea Nakai, and Ternstroemia gymnanthera. And the English name are Japanese Ternstroemia and Japanese Cleyera. "Bizooki" tree has planted at Buddhist temples in Japan for the ritual. The best result of stem cutting in "Bizooki" tree, 100 percent of rooting, could be accomplished in July when cuttings were done on the mixture-soil containing the same rates by volume of vermiculite, peatmoss and perlite with cuts processed with IBA 1,000 mg/l under the circumstances that 70% of shade, plastic mulching, and mist were conditioned.

• 한국공간정보시스템학회:학술대회논문집
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• 2003.11a
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• pp.141-146
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• 2003

시간이 흐름에 따라 연속적으로 위치를 변경하는 객체를 이동 객체(Moving Objects)라고 한다. 이러한 이동 객체의 대용량 위치 정보를 효율적으로 검색하기 위하여 색인이 필요하며, 대표적인 색인으로 TB-tree가 제안되었다. 그러나 전통적인 R-tree 기반의 TB-tree는 엄격한 궤적 보존 정책에 의해 레코드가 삽입될 때마다 해당 레코드의 선행자(predecessor)를 포함하는 단말 노드를 검색해야 하며, 레코드 삽입으로 인한 단말 노드 MBB의 변경을 중간 노드들의 MBB에도 반영해야 하는 갱신 부하를 가지고 있다. 본 논문에서는 대용량 이동 객체 궤적 정보의 효율적인 색인을 위한 최소 전파 TB-tree를 제안한다. 본 기법은 앞으로 삽입될 이동 객체의 궤적을 포함하는 예상된 MBB(EMBB: Expected Minimum Bounding Box)를 트리에 먼저 반영한 후 레코드가 삽입될 때마다 중간 노드의 MBB를 갱신하지 않고, 객체가 EMBB을 벗어났을 때 중간 노드의 MBB를 조정하여 TB-tree의 MBB조정 횟수를 줄이고, 또한 TB-tree에 별도의 테이블 구조를 둠으로써 레코드 삽입을 위한 단말 노드 검색 비용을 줄여 전체적인 TB-tree의 갱신 비용을 감소시킨다.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.76-83
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• 2015

Old growth and protected-trees are worth history and culturally in Korea. This research carried out to investigate habitat characterization and the vegetative propagation methods of Salix chaenomeloides(100-600 years old trees) in Gyeongsangnamdo Province. It has been preserved in good and grow naturally in area surrounding village(4 trees), riverside(1 tree) and field(1 tree). Cutting from old growth and protected trees was conducted using 10 kinds of bedsoils. It was survived above 93% in all bedsoils. Growth of cuttings is a distinct difference according to bedsoils and tree ages. Growth of cutting was high on CBS, followed mixed bedsoils(VPMP) including vermiculite, peatmoss and perlite. Root collar diameter was difference depend on tree ages and bedsoils. All trees are produced 1 to 4 branch. Root growth of cutting was 20 cm on CBS and VPMP, which is the best shoot growing on cutting. Bedsoil with physico-chemical characteristics of high moisturizing ability, high air permeability, high EC value and slightly acid may be suitable for efficiently cutting propagation of old growth and protected S. chaenomeloides. CBS and VPMP bedsoil are favorable for propagating this species by cuttings.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.107-113
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• 2002

This study was performed to obtain the information on fruit set, propagation and flowering habits of the exotic ornamental bottle brush tree (Callistemon citrinus). Trees have fruit capsules for four years since the fruit set and they have enlarged for three years. While 2 and 3-year-old capsules have similar seeds in number and size, 1-year-old ones have fewer and smaller seeds. Most dried capsules open when they have 75％ relative water contents. Two year old seeds which they were dried at 30％ germinated better than others. Removal of capsule bearing twigs resulted in greatly increased subsequent flower numbers (an average of 14 flowers per tree) compared with twigs where seed capsule were allowed to remain. In cutting for propagation, semi-hard wood branches dipped in 100mgι$^{-1}$ IBA for 24 hours rooted at 86.4 ％ and had an average of 12.6 primary roots.

• Landscaping Tree
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• v.81 no.7_8
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• pp.18-21
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• 2004

하늘나리, 참나리, 섬말나리, 땅나리... 자생화 중 나리류 만큼 꽃이 크고 원색적인 것도 흔치 않다. 나리류는 전 세계적으로 130여종이 있는데 이 중 71종이 아시아에 분포하고 있다. 북반구의 아열대에서 아한대지역까지 집중되어 있으며 해발 2,000~2,500m 정도의 고지대에도 자생한다. 우리나라도 매우 중요한 나리 원산지 중의 한 곳으로 변종을 포함 전국에 15종이 자생하고 있다. 특히 솔나리는 꽃색이 분홍색으로 나리의 주요 육종모본으로 이용되고 있으며, 섬말나리는 울릉도에 분포하며 희소가치가 비교적 큰 식물이다.

• Landscaping Tree
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• v.80 no.5_6
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• pp.14-16
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• 2004

부처꽃 하면 초여름에 곧게 뻗은 빨간 꽃차례도 아름답지만 자생화 중 가장 수명이 긴 화종이라는게 생각난다. 몇 년 전 우리 자생화들의 종자수명을 알아보고자 냉장고에서 보관 중이던 약 50종의 종자를 당년산부터 최장 12년산까지 뿌려 발아력을 조사한 적이 있는데, 당시 부처꽃만 100% 가까이 발아되어 정말 수명이 긴 종류구나 하는 것을 느꼈던 기억이 난다. (중략)