• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.304-311
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• 2000

This study was conducted to investigate the ratio and number of the Rhus javanica gall formed by chinese sumac aphid, Scheleechtendalia chinensis, in several different conditions in which R. javanica lives. The density of 11 to 15-year-old R. javanica was more higher and the number of galls was also higher than 1 to 5- or over 16-year-old one at these sites. The formed gall according to four directions such as the East, West, South and North was founded the highest at the East and followed South, North, and West order. The formative rate of R. javanica gall did not differ in the mixture forest, and in the habitat having a heap of a little stone and mosses near a valley was better than in the site of road perimeter. Through an index of the gall diameter and the number of chinese sumac aphid, we evaluated the gall processing and development formed by the aphid. As the density of aphids increase, the size of the gall was also more plumped. The part of phyllotaxy of R. javanica gall in leaf and pinnate of was increased in the middle and upper part of terminal leaflet and leaflet was more occupied than wing. R. javanica which did not form a gall in natural environmental, formed gall by a artificial inoculation of S. chinensis. Some gall disappeared during a gall development from various environmental conditions.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.170-177
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• 2007

The objectives of this study were to select early, late, and abundant flowering trees of black locust from domesticated and introduced cultivars, and prediction of flowering period by calculation of accumulated temperature in spring. Four cultivars (Debreceni-2, Pusztavacs, Jaszkiseri, and Rozsaszin AC) from Hungary and a cultivar from Beijing, China, were introduced, propagated by seed and planted in a seed orchard. For domesticated black locust, 63 cultivars from 10 locations throughout the country were selected and propagated by root cutting. Criteria for selection of domesticated cultivars were abundant flowering, long flowering period, or abundant nectar production with, if possible, straight stems. Accumulated temperature was calculated from data of a nearby weather station by accumulating daily maximum temperature minus 5 degree Celsius from January 1 up to the date reaching 880 degrees. Daily mean temperature was also used to calculate accumulated temperature up to the date reaching 450 degrees. The percentages of two-year and three-year-old flowering trees propagated by root cutting were higher than that of trees propagated by seeds, while four-year-old trees all flowered regardless of propagation methods. Among the domesticated cultivars, all the cultivars from Ganghwa showed abundant flowering with highest nectar production of 6.5 ul per flower, which was 100% more than other domesticated cultivars and 50% more than Debreceni-2 cultivar with highest nectar production among the introduced cultivars from Hungary. At the end of the eight years of observations, two trees of Debreceni-2 cultivars and a tree from Beijing, China were selected for early flowering trees which flowered 2 to 3 days earlier than average trees, while a tree of Debeceni-2 and three trees from Bejing were selected for late flowering trees which flowered 2 to 3 days later than average trees. It is possible to extend the flowering period of black locust by 4 to 6 days by planting early and late flowering cultivars together. Abundant flowering trees were unable to be selected due to severe damages by leaf gall midges which killed many trees and reduced the crown size of the remaining trees in the seed orchard, and which were first found in Korea in 2001 and now damaging most of the black locust forests in Korea. The prediction of flowering period by accumulated temperature indicated that black locust flowered to a peak when accumulated daily maximum temperature reached 880 degrees Celsius, and when daily mean temperature reached 450 degrees.

• Journal of KIISE:Databases
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• v.29 no.5
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• pp.367-380
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• 2002

Due to recent increase in applications requiring huge amount of data such as spatial data analysis and image analysis, clustering on large databases has been actively studied. In a hierarchical clustering method, a tree representing hierarchical decomposition of the database is first created, and then, used for efficient clustering. Existing hierarchical clustering methods mainly adopted the bottom-up approach, which creates a tree from the bottom to the topmost level of the hierarchy. These bottom-up methods require at least one scan over the entire database in order to build the tree and need to search most nodes of the tree since the clustering algorithm starts from the leaf level. In this paper, we propose a novel top-down hierarchical clustering method that uses multidimensional indexes that are already maintained in most database applications. Generally, multidimensional indexes have the clustering property storing similar objects in the same (or adjacent) data pares. Using this property we can find adjacent objects without calculating distances among them. We first formally define the cluster based on the density of objects. For the definition, we propose the concept of the region contrast partition based on the density of the region. To speed up the clustering algorithm, we use the branch-and-bound algorithm. We propose the bounds and formally prove their correctness. Experimental results show that the proposed method is at least as effective in quality of clustering as BIRCH, a bottom-up hierarchical clustering method, while reducing the number of page accesses by up to 26～187 times depending on the size of the database. As a result, we believe that the proposed method significantly improves the clustering performance in large databases and is practically usable in various database applications.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.355-360
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• 1996

In vitro-tested ribozyme against synthesized cucumber mosaic virus (CMV) RNA (Agric. Chem. & Biotech. 37:56-63(1994)) was expressed in tobacco plant to develop virus resistant plants. The ribozyme sequence was linked to cauliflower mosaic virus 35S promoter and nopaline synthase(nos) terminator and this chimeric 35S-ribozyme-nos gene was sequenced. The sequenced chimeric gene was transferred to Agrobacterium tumefaciens LBA4404 using tri-parental mating system. The E. coli HB101 containing chimeric gene was incubated with E. coli HB101(pRK2073) as a helper and Agrobacterium tumefaciens LBA4404. Then Agrobacterium cells containing the ribozyme construct was cocultivated with tobacco leaf pieces. Ten different plants were regenerated from kanamycin containing MS medium. The presence of the ribozyme construct in the transgenic tobacco plants was confirmed by polymerase chain reaction (PCR). Seven different transgenic plants in ten different kanamycin resistant plants showed the expected size (570 base pairs) of 35S-ribozyme-nos gene fragment. Total RNAs were isolated from four different transgenic plants and separated on a 1% agarose gel containing formamide. Northern hybridization with 35S-ribozyme-nos gene fragment as a probe indicated that ribozyme transcripts may be degraded tv nuclease. Therefore, nuclease-resistant ribozymes are needed for the development of virus-resistant transgenic plants using ribozymes.

• The KIPS Transactions:PartD
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• v.18D no.4
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• pp.225-236
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• 2011

Various applications of LBS (Location Based Services) are being developed to provide the customized service depending on user's location with progress of wireless communication technology and miniaturization of personalized device. To effectively process an amount of vehicles' location data, LBS requires the techniques such as vehicle observation, data communication, data insertion and search, and user query processing. In this paper, we propose the historical location index, GIP-FB (Group Insertion tree with Flexible Buffer Node) and the flexible buffer node technique to adjust the cost of data insertion and search. the designed GIP+ based index employs the buffer node and the projection storage to cut the cost of insertion and search. Besides, it adjusts the cost of insertion and search by changing the number of line segments of the buffer node with user defined time interval. In the experiment, the buffer node size influences the performance of GIP-FB by changing the number of non-leaf node of the index. the proposed flexible buffer node is used to adjust the performance of the historical location index depending on the applications of LBS.

• Research in Plant Disease
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• v.14 no.1
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• pp.68-70
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• 2008

Brown leaf spots on leaves of kiwifruit(Actinidia deliciosa) were observed at farmers' orchards in Suncheon and Goheung, Jeonnam Province, Korea in June, 2006. They developed to form dark brown ring spots and severely infected leaves resulted in defoliation during the growing season of kiwifruit. Alternaria sp. was isolated from the diseased leaves repeatedly and was identified as Alternaria alternata on the basis of its mycological characteristics on potato dextrose agar and its pathogenicity was confirmed by wound inoculation on healthy leaves of kiwifruit. A. alternata formed gray to dark sooty gray colony and produced numerous conidia on potato dextrose agar. The conidia, commonly in long chains of 5 or more produced on conidiophores, have $3{\sim}5$ transverse and $1{\sim}2$ longitudinal septa and mostly ovoid or obclavate in shape and were pale brown golden brown in color. The condia were $16.5{\sim}42.1{\times}6.7{\sim}19.5\;{\mu}m$ in size and conidiophores were $8.6{\sim}112.7\;{\mu}m$ in length. This is the first report on the brown ring spot on leaves of kiwifruit caused by A. alternata in Korea.

• Research in Plant Disease
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• v.12 no.2
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• pp.115-118
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• 2006

In February of 2000-2001, the gray mold disease occurred on nephrolepis (Nephrolepis sp.) grown in a flower nursery farm in Suwen, Korea. Typical symptoms were water-soaked brown or blackish lesions on terminal leaf blades. Severely infected leaves were entirely blighted with grayish fungal mycelia formed on the surface. Conidia of the fungus in mass were hyaline or gray, 1-celled, mostly ellipsoid or ovoid and $13.5{\sim}16.9{\times}6.8{\sim}9.2{\mu}m$ in size. Conidiophores were formed on PDA with $8.7{\sim}11.1{\mu}m$ in width. The sclerotia were readily formed within 2 or 3 days on PDA. In addition, the Biolog database gave the causal fungus a high similarity to Botrytis cinerea (78%) with a match probability of 100%. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Eotrytis cinerea based on its mycological characteristics and utilization of carbon sources with Biolog system as supporting data. This is the first report of gray mold of nephrolepis caused by Botrytis cinerea in Korea.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.256-259
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• 2016

An obligate plant pathogenic fungus Puccinia zoysiae Dietel, the causal agent of rust disease, which is implicated in the damage of zoysiagrass (Zoysia spp.) in Korea. The fungus is one of the important pathogens, which attacks and colonizes susceptible zoysiagrass. Zoysia rust disease was observed in Jangseong, Hoengseong and Hapcheon in 2014 and 2015, Korea. The typical symptoms of the disease appeared first as small white spots on the leaf and stem of zoysiagrass plants, and turn brownish, dark brown spores revealed on the lesions. Uredospores were light brown in color, ellipsoid or spherical in shape and $22.0{\sim}25.0{\times}15.0{\sim}17.5{\mu}m$ in size. On the basis of the morphological characteristics, the fungus was identified as P. zoysiae. Pathogenicity of the fungus was proved by artificial inoculation on Z. japonica. The rust disease firstly appeared approx. early or middle June and then increased middle of October in Korea. In field, Z. matrella ecotypes were more resistant than Z. japonica ecotypes against the pathogen. Disease response against the pathogen was different among ecotypes of each species, respectively.

• Parasites, Hosts and Diseases
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• v.32 no.3
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• pp.143-148
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• 1994

The metacercanae of the genus Stictodora encysted in gobies, Acnnthogobiln Snuimanw, purchased from a local market of Haenarn-gun, Chollanam-do, were identified as those of S. fuscotum A total of 1,437 metacercariae were collected from 30 gobies and sonle of them were orally fed to cats in order to obtain the adult worms. The metacercariae were 0.194-0.301 mm by 0.168-0.270 mm In size, yellowish brown, round to elliptical, and with a thin and transparent cyst wall. The excysted larvae were 0.280-0.423 mm long and 0.150-0.184 mm wide, beset with numerous tegumental spines on the anterior half of the body, and equipped 10 a characteristic ventrogenital sac. Total 21 adult worms were recovered from 2 cats 7 days after infection. The adult worms were small, leaf-like, 0.514-0.918 mm long and 0.235-0.377 mm wide. The ventrogenital sac was elliptical and its gonotyl was armed with 13-18 spines which were radially arranged and appeared as fan-shape. It has been confirmed that A. flavimanus is a second interinedlate host of 5. Juscatum In Korea.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.7-11
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• 2003

Cellular glass foam (CGF), the reprocessed glass, has a possibility to be used as a medium component in plug culture of horticultural crops due to the its excellent air and water permeability as comparable to perlite. An experiment was conducted to investigate growth of plug seedlings of Lycopersicum esculentum 'Segye' as influenced by irrigation frequency in various medium combinations of CGF (2.0-4.0 mm particle size) and peatmoss. Seeds were sown in 200-cell plug trays, filled with mixtures of CGF and peatmoss either at 33：67 or 25：75 (％. v/v) and were germinated on a fogged propagation bed. The irrigation frequencies used were one, two or three times per every two days. A commercial plug medium (Tosilee medium) was used as the control, and the irrigation frequency in the control was one time per day. Growth of seedlings, and medium pH and EC were measured at 33 days after sowing. The medium composition had little influence on overall growth of seedlings. Irrigation frequency very significant affected number of leaves, leaf area, chlorophyll concentration, fresh and dry weights of shoots and roots, and dry matter. Growth of seedlings was the greatest with the highest irrigation frequency in the 25% CGF＋75% peatmoss mixture.