• Journal of Korean Society of Forest Science
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• v.95 no.3
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• pp.282-290
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• 2006

Forest vegetation types were studied by the phytosociological investigation and the TWINSPAN method in Ulleung Island, Korea. Two hundred thirty-two releves were sampled with $100m^2$ plots. Two main vegetation types, the mountain forest(Acer okamotoanum community group) and maritime forest(Artemisia scoparia community group), have been distinguished and typified twenty-two vegetation units. The former was divided in 4 communities, 11 groups and 7 subgroups. The latter was 2 communities and 5 groups. In a case of life-forms of mountain and maritime vegetation type, the composition ratio of species that had featured trees and herbs, hemicrypthophyte, a seed dispersion-type by wind or nature falling and erection form was high in the mountain vegetation type. Species that had featured shrubs, chamaephyte, disseminated mainly by a wind in the herbs, and animals and man or no special modification in the woody, narrowest extent of rhizomatous growth and the clonal growth by stolons and struck roots and procumbent form were abundantly distributed in the maritime bluff vegetation type. Particularly, the composition ratio of Sambucus sieboldiana var. pendula community(A6), disturbed vegetation type of middle-lower slope of mountain, that had featured a seed dispersion-type by wind, moderate and narrowest extent of rhizomatous growth and Tussock form was high.

• Journal of Forest and Environmental Science
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• v.24 no.2
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• pp.89-97
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• 2008

Based on the former researches, this article studied the influence of cone harvesting of Korean pine on the regeneration of Korean pine trees and the life of animals in Mt. Changbai Nature Reserve. When the cone matures, scales of the cone do not open so the seeds can not be released automatically. And the seeds, if left inside, are hard to germinate and can not grow further into seedlings. The seeds of Korean pine have deep dormancy characteristics. Natural regeneration of Korean pine is very poor under mother trees. Hoarding behavior of dispersing animals not only helps animals for food shortage period but also contributes to the dispersion of seeds of Korean pine. Among those hoarding animals, squirrel and Eurasian nutcrackers are found to be the most important dispersing agents for the seeds of Korean pine. After cone harvesting, the number of those dispersers reduced a lot since the seeds of Korean pine are very important food for them. Seed quantity of Korean pine on surface layer became very few and most of them only showed single distribution. Most of the seeds were buried under litter layer and showed a single or 2-4 seeds/cluster distribution. The case of more than 4 seeds in one cluster was few. The seed quantity of Korean pine forest on steep slopes of the research area was only 0.3% of the seed quantity in 1980 for the same forest type. If seed source of Korean pine are not protected, Korean pine forest in Mt. Changbai Nature Reserve would not maintain present feature in the future.

• Convergence Security Journal
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• v.10 no.2
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• pp.19-26
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• 2010

In this study, we try to make up for the vulnerability in steganography that it is easily revealed the hidden logo image in cover image by bit-plane extraction. For this, we apply some methods, the permutation which shift the scattered pieces of logo image to one side, bit-plane dispersion insertion method and pack-type compressor.

• Korean Journal of Materials Research
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• v.22 no.8
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• pp.433-438
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• 2012

A chemical process involves polymerization within microspheres, whereas a physical process involves the dispersion of polymer in a nonsolvent. Nano-sized monodisperse microspheres are usually prepared by chemical processes such as water-based emulsions, seed suspension polymerization, nonaqueous dispersion polymerization, and precipitation polymerizations. Polymerization was performed in a four-necked, separate-type flask equipped with a stirrer, a condenser, a nitrogen inlet, and a rubber stopper for adding the initiator with a syringe. Nitrogen was bubbled through the mixture of reagents for 1 hr. before elevating the temperature. Functional silane (3-mercaptopropyl)trimethoxysilane (MPTMS) was used for the modification of silica nanoparticles and the self-assembled monolayers obtained were characterized by X-ray photoelectron spectroscopy (XPS), laser scattering system (LSS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), elemental analysis (EA), and thermogravimetric analysis (TGA). In addition, polymer microspheres were polymerized by radical polymerization of ${\gamma}$-mercaptopropyl modified silica nanoparticles (MPSN) and acrylamide monomer via precipitation polymerization; then, their characteristics were investigated. From the elemental analysis results, it can be concluded that the conversion rate of acrylamide monomer was 93% and that polyacrylamide grafted to MPSN nanospheres via the radical precipitation polymerization with AAm in ethanol solvent. The microspheres were successfully polymerized by the 'graft from' method.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.68-83
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• 2010

Weedy rice (Oryza sativa L.) occurred sympatrically with other weeds and the rice crop in Malaysian rice granaries. We conducted field surveys in 2006-2008 seasons in 7 farm blocks of Selangor's North West Project, Malaysia to enlist the new biotypes of weedy rice (NBWR) and assess their spatio-temporal pattern of distribution based on quantitative and dispersion indices. No less than 16 accessions of NBWR were identified based on their special traits, viz. panicle type, pericarp colour, presence or absence of awn, seed type and degree of grain shattering. The NBWR accessions exhibited a combination of morphological traits from open panicle, grain with awns, red pericarp, short grain type, and degrees of grain shattering. Others mimic commercial rices with close panicle, awnless grains, white pericarp, long or short grain-type. Invariably, the NBWRs mimic and stand as tall as cultivated rice namely MR219, MR220, or MR235 and these NBWR accessions stand among equals morphologically vis-a-vis the commercial rice varieties. Most accessions displayed varying degrees of grain shattering in excess of 50%, except Acc9 and Acc12. The seasonal dynamics of on the prevalence of dominant NBWR accessions were also displaying significant differences among farm blocks. While Bagan Terap farm block, for example, did not record any measurable changes in the dominant NBWR accessions over seasons, the Sungai Leman farm block recorded measurable season-mediated changes in the dominant NBWR accessions. Sungai Leman started with NBWR Acc3, Acc4, Acc5, Acc7, Acc8, and Acc12 in season 1 of 2006/2007, but no measurable records of Acc3 and Acc5 were shown in season 2 of 2007. In season 3 of 2007/2008, only Acc8 and Acc12 prevailed in the farm block. In Sawah Sempadan farm block, season 3 of 2007/2008 showed much reduced prevalence of NBWRs leaving only Acc8 and Acc12. Most accessions registered clump or under-dispersed spatial distribution pattern based on quantitative indices: variance-to-mean ratio (VMR) and Lloyd's patchiness values. The dynamics on the extent of infestation and prevalence of dominant NBWR accessions registered both season- and farm-block mediated differences. Most accessions showed VMR >1 thus indicative of having a clump or clustered spatial distribution, as exemplified by Acc3, Acc4, Acc7, Acc8 and Acc12 in all farm blocks throughout three seasons. Some accessions have either random or uniform distribution in a few farm blocks. The Acc8 has the highest population counts based on important value index, followed by Acc12, and both were the most dominant accession while Sawah Sempadan was the worst farm block infested by NBWR compared to other farm blocks. These results were discussed in relation with the current agronomic and weed management practices, water availability and extension services in the granary.

• Korean Journal of Plant Taxonomy
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• v.37 no.4
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• pp.545-563
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• 2007

The investigated vascular plants of Dok-do island were confirmed that consisted of 46 species, 1 subspecies, 1 varieties in total of 48 taxa growing spontaneously. 1 taxa of Pteridophyta, 36 taxa of Dicotyledon and 11 taxa of Monocotyledon identified. In 48 identified taxa in this study, total 13 taxa included Orobanche coerulescens Stephan, Fallopia sachalinensis (F. Schmidt) Rouse Decr., Lonicera insularis Nakai identified according to the Korean plant taxa for environmental assessment. Planting species were about 10 taxa included Pinus thunbergii Parl., Hibiscus syriacus L. and etc. Four species confirmed in this study such as between Chenopodium virgatum Thunb. and Chenopodium album L., Echinochloa crusgalli (L.) P.Beauv. and Echinochloa crusgalli var. oryzicola (Vasinger) Ohwi. were doubt on identification in taxonomic entity due to morphological characteristics. The dispersion type of Do-kdo plants were anemochore 31 taxa, zoodchore 8 taxa, hydrochore 2 taxa and the others by artificial means.