• 한국산림과학회지
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• 제95권3호
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• pp.282-290
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• 2006

울릉도 산림식생의 유형은 총 232개 조사구를 토대로 식물사회학과 TWINSPAN분석에 의해 구분되었으며, 유형별 생활형조성이 분석되었다. 이 지역의 산림식생유형은 모두 22개 식생단위로 나타났으며, 크게 산지식생과 해안식생의 2개 광역그룹으로 대별되고, 전자는 4개 군락, 11개 군, 7개 소군, 후자는 2개 군락, 5개 군의 체계를 나타내었다. 산지식생과 해안식생의 생활형조성 특성을 보면 전자는 교목성과 초본성식물, 반지중식물, 바람에 의한 산포와 자연낙하기관형, 직립형식물 등의 구성비가 상대적으로 높았고, 후자는 관목성식물, 지표식물, 바람과 동물에 의한 산포기관형, 좁은 범위에 연락체를 만드는 유형과 포복경식물의 구성비가 높았다. 특히 산지식생형의 하위단위에 속하는 말오줌나무군락(A6)은 교란의 영향으로 바람에 의한 산포기관형, 약간 넓은 범위에 연락체를 만드는 유형과 덩굴형의 식물의 구성비가 높게 나타났다.

• Journal of Forest and Environmental Science
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• 제24권2호
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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.

• 융합보안논문지
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• 제10권2호
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• pp.19-26
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• 2010

본 연구에서는 정보은닉을 위한 스테가노그라피에 대한 연구로서 은닉기법에서 비트 플레인 추출방법을 통하여 쉽게 나타나지는 문제점을 보완하였다. 즉, Cover 이미지에 Logo 이미지를 은닉함에 있어 비트 플레인 분산방식 후 Pack 형식을 이용한 코드 빈도 조사와 연속값 조사 등을 통해 압축하여 용량을 줄인 후, Embedding하며 그때 seed 값을 주어 암호화를 높임으로써 쉽게 추출당하지 않을 수 있도록 하였다. 비트 플레인 추출방법은 (0-7)비트 중 어느 한 해당하는 비트에 값을 넣기 때문에 특정 비트에서 값이 보여 지는 문제점이 발생하기 하므로 이를 보완하기 위해 Premutaion 후 흩어져 있는 로고 이미지를 한쪽으로 쉬프트 시키는 Permutation 보완작업과 비트 플레인 분산삽입 방식, 팩 형식의 압축 프로그램 등을 적용하였다.

• 한국재료학회지
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• 제22권8호
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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.

• 한국잡초학회지
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• 제30권2호
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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.

• 식물분류학회지
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• 제37권4호
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• pp.545-563
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• 2007

2005년 11월부터 2006년 11월까지 총 4회에 걸쳐 독도의 유관속식물상을 조사하였다. 독도에서는 26과 44속 46종 1아종 1변종으로 총 48분류군이 확인되었는데, 이는 양치식물 1분류군, 쌍자엽식물 36분류군, 단자엽식물 11분류군으로 이루어져 있다. 식물구계학적 특정식물로는 V등급종인 초종용(Orobanche coerulescens Stephan)과 IV등급종인 왕호장근[Fallopia sachalinensis (F.Schmidt) RonseDecr.], 섬괴불나무(Lonicera insularis Nakai), 섬초롱꽃(Campanula takesimana Nakai), 왕김의털(Festuca rubra L.) 등 총 13분류군이 확인되었다. 식재된 종으로는 곰솔(Pinus thunbergii Parl.), 동백나무(Camellia japonica L,) 보리장나무(Elaeagnus glabra Thunb), 무궁화(Hibiscus syriacus L.) 등이 있다. 분류학적으로 실체가 의심되는 종(species)으로는 가는명아주(Chenopodium virgatum Thunb.), 돌피[Echinochlca crusgalli (L.) P.Beauv.]로써 각각 흰명아주(Chenopodium album L,), 물피[Echinochloa crusgalli var. oryzicola (Vasinger) Ohwi]와 구분되는 형질을 공유하거나 불분명하여 동정에 있어서 혼란이 야기된다. 종유입 방법별로는 풍산포(anemochore) 31분류군, 동물산포(zoochore) 8분류군, 해류산포 (hydrochore) 2분류군인 것으로 판단되며, 이외의 종들은 인위적 수단에 의하여 유입된 것으로 보인다.