• Journal of the Korean Geographical Society
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• v.30 no.1
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• pp.1-13
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• 1995

One of the oldest fossil of conifers and taxads in the Korean peninsula includes Elatocladus, Ullmannia, Walchia and dates back to the Permian period of the Palaeozoic era. The only conifer which successfully survived since the Cretaceous period is Pinus and still thrives in Korea. The extinction of Miocene conifers, such as Sciadopitys, Taxodiaceae, Metasequoia and Cryptomeria may due to the climatic deteriorations during the late Pleistocene period. However, the cryophilous conifers and taxads, e.g..Pinus, Juniperus, Abies, Picea, Cupressaceae, Larix and Taxus continued to exist from the Miocene to the late Pleistocene and became major vegetational elements in the mountainous areas of Korea. As the temperature ameliorates in the late Holocene period, thermophilous Pinus (Diploxylon) gradually had increased in numbers and became a dominant vegetation in the lowland and montane areas since 2,000 years B.P. in korea. Out of various Korean conifers and taxads, Pinus which surviving since the Cretaceous period of Mesozoic era, ranges spatially from southern coastal area to northern alpine belt of the Korean peninsula. Pinus which contains largest species number in conifers is one of the most well-adapted genus to the Korean environment. The next important conifer Juniperus dates back to the Miocene period of Cenozoic era and continuously maintains speciation and expansion of distributional range. Other major conifers and taxads of Korea include Picea, Abies, Lorix and Taxus. The restriction of distributional range of Cephralotaxus and Tsuga may due to the climatic deterioration during the Pleistocene period of Cenozoic era. The patterns of the temporal and spatial distribution of Korean conifers and taxads may provide invaluable informations for the better understanding of present-day distributional range and ecology.

• Korean Journal of Plant Taxonomy
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• v.43 no.1
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• pp.46-55
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• 2013

The purpose of this study is to review the taxonomic position of Taxus cuspidata var. latifolia endemic to Ulleung Island with related taxa T. cuspidata var. cuspidata, T. caespitosa, and T. cuspidata var. nana based on external morphological characters and DNA barcoding study. T. cuspidata var. latifolia was similar to T. cuspidata var. cuspidata in the arbor, straight trunk, and symmetric arrangement of leaf. But the unique differences between T. cuspidata var. latifolia and T. cuspidata var. cuspidata were leaf size and the exposure of seed from aril. Additionally, sequences of four chloroplast DNA regions including matK, rbcL, trnL intron and trnL-trnF spacer regions were analyzed. Korean Taxus species and their related taxon T. cuspidata var. nana were strongly supported as a monophyletic group in neighbor-joining analysis. Taxus cuspidata var. latifolia showed 100% sequence identity to related taxa. Korean endemic T. caespitosa is also distinguishable from related taxa by prostrate stems and spiral arrangement of leaf. The examinations of external morphology and DNA barcoding study suggest that the taxonomic position of T. cuspidata var. latifolia should be maintained as a variety of T. cuspidata.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.597-602
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• 2005

The Late Quaternary palynoflora from an archaeological site in Piseo-ri, Muan, Korea consists predominately of deciduous broadleaved angiosperms and subordinately of herbs and conifers. Dominant taxa are Polypodiaceae, Taxodiaceae-Cupressaceae-Taxaceae, Alnus, Carpinus, deciduous Quercus, Compositae and Gramineae. The palynoflora dated 43,000-18,000 yr BP, corresponding to the last glacial period, is similar to the modern vegetation of the cool temperate deciduous broadleaved forest in the middle part of the Korean Peninsula. Based on palynofloral composition, three palynozones are recognized. Zone I represents a cool temperate deciduous broadleaved forest, composed of Polypodiaceae, Taxodiaceae-Cupressaceae-Taxaceae, Alnus and D. Quercus, and is characterized by persistent occurrence of warm temperate taxa. Zone II shows drastic decrease in Polypodiaceae, Taxodiaceae-Cupressaceae-Taxaceae, and increase in herbs. This zone reflects a cool temperate deciduous broadleaved forest with scattered open grasslands. Zone III is characterized by dominance in herbs and increase in conifers. The palynofloral composition suggests a cool temperate climate, and variation in occurrences of main taxa indicates that climatic conditions gradually became cold and dry.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.248-248
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• 2022

Hwang(2015)은 불연속 지형을 지나는 천수 흐름의 수치 해석에서 불연속 전면에 의한 추력(thrust)에 주목하여 그 영향을 흐름률(flux) 계산에 반영하는 새로운 기법을 제시하였다. 이 기법 덕분에 수심 적분 모형으로도 계단이나 보와 같이 직립한 하천 구조물의 불연속면을 경사로 완화하지 않고 직접 모의할 수 있다. 직립 측면 위어 실험에 Hwang(2015)의 기법이 적용됨으로써 연직면을 경사면으로 완화하여야 하는 기존의 수심 적분 모형에 비해 계산 격자 개수가 53%로 줄었다(Hwang, 2019). Hwang(2019)은 기존 모형과 비교를 통해, 정확도를 어느 정도 유지하면서도, 소요된 계산 시간이 20%에 불과하다고 주장하였다. 여기에서는 보다 다양한 직립 광정 위어 실험에 적용하여 수심 적분 모형에 의한 월류량을 검토하고자 한다.

• Korean Journal of Plant Resources
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• v.33 no.4
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• pp.398-403
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• 2020

Plagiothecium platyphyllum Mönk (Plagiotheciaceae), a species unrecorded previously in the moss flora of the Republic of Korea (South Korea), was collected in the Surak stream of Mt. Daedun in Jeollabuk-do Wanju-gun Sanbuk-ri. This species was known to be distributed around China, Japan, North Korea, and Europe. The morphological characters of P. platyphyllum's leaf are ovate-lanceolate, and mostly asymmetric, 2.0~2.5 × 1.0~1.4 mm. The margin of the leaf is entirely below and weakly serrulated near the apex. The costae parts are double, unequal, with one branch reaching to the mid-leaf. Median leaf cells are linear-rhomboidal, 80~127 × 10~16 ㎛ and alar cells are rectangular. Central strand is developed in the core of the stem.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.121-126
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• 2004

An efficient multi face detection technique is proposed based on hierarchical context-free attention operators in which multiple faces are efficiently detected from a noisy and complex background. A noise-tolerant generalized symmetry transform (NTSGT) is applied hierarchically, as a context free attention operator, to the input pyramidal image for the high speed global location of the regions of face candidates (ROFCs) with a single mask. For the face verification, local NTGST is applied within each ROFC to confirm the existence of the detailed facial features. First, by globally applying NTGST which introduces the average pyramid method and focusing to the input image with complex background, ROFCs with recognizable resolution are detected robustly. Morphological operations are applied only to the each detected ROFCs to emphasize the facial features like eyes and lips. Then, eyes are detected by locally appling NTGST to the ROFCs and only faces are detected by verifying the existence of the geometrical features of the faces relatively to the location of eyes. The experimental results show that the proposed method can efficiently detect multiple faces from a noisy or complex background with 93.5% detection rate.

• Journal of The Korean Association For Science Education
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• v.39 no.1
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• pp.101-113
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• 2019

This study aims to explore which aspects of student agency have previously been studied and the ways agent practices have been investigated in learning communities in research on science education. Results reveal five aspects of agency related to students' actions in a learning community: epistemic agency, transformative agency, educated action in science, disciplinary agency, and material agency. We delineated how agency is captured in epistemic practices, as described in the literature on each of the aforementioned aspects. We also probed into the three approaches by which previous research has examined the practices of students as agents that construct learning communities. These approaches are (a) the investigation of students' actions as representative of the agency of an entire learning community, (b) the exploration of the effects of focused student action on the structure of activity, and (c) the investigation of interactions between students as agents. We discussed the implications of previous research on the basis of each approach to understanding the diverse features of student-centered learning communities. The present work contributes to the exploration and support of students' practices as agents in the learning communities in science classrooms.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.745-756
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• 2009

An autonomous virtual character can conduct itself like a human after recognizing and interpreting the virtual environment. Artificial vision is mainly used in the recognition of the environment for a virtual character. The present artificial vision that has been developed takes all the information at once from everything that comes into view. However, this can reduce the efficiency and reality of the system by saving too much information at once, and it also causes problems because the speed slows down in the dynamic environment of the game. Therefore, to construct a vision system similar to that of humans, a visual observation system which saves only the required information is needed. For that reason, this research focuses on the descriptive artificial intelligence engine which detects the most important information visually recognized by the character in the virtual world and saves it into the memory by degrees. In addition, a visual system is constructed in accordance with an image transaction theory to make it sense and recognize human feelings. This system finds the attention area of moving objects quickly and effectively through the experiment of the virtual environment with three dynamic dimensions. Also the experiment enhanced processing speed more than 1.6 times.

• Journal of the Korean earth science society
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• v.26 no.3
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• pp.276-282
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• 2005

The Quaternary palynoflora from Cheongsu core, drilled on the western part of the Jeju Island, consists mainly of deciduous broad-leaved angiosperms and herbs. Dominant taxa are Pinaceae, Alnus, Castanea/Castanopsis, Ulmus/Zelkova, Chenopodiaceae and Compositae. Based on palynofloral composition, two palynostratigraphic zones are recognized. Zone I is characterized by a predominance of Alnus and Chenopodiaceae, and by the abundance of herbs. Zone II is dominated by conifers and deciduous broad-leaved angiosperms, including Abies, Taxodiaceae-Cupressaceae-Taxaceae, Ulmus/Zelkova and Gramineae. The Cheongsu palynoflora can be correlated with Alnipollenites(Alnus)-Chenopodipollis(Chenopodiaceae)-Compositae Assemblage Zone of the East China Sea and is assigned to the Pleistocene in age. Ecology of main taxa and comparison with the present vegetation of Korea suggest a cool temperate climate and a low relief in the Jeju Island during the deposition of the Cheongsu core sediments.

• The Science & Technology
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• v.26 no.7 s.290
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• pp.95-97
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• 1993

남북한이 분단된지 반세기가 다 되었으므로 여러 영역에서 남북한간에 이질화가 일어나는 것은 어쩌면 당연하고 자연스러운 일이라고 생각할 수 있다. 그러나 이러한 이질화가 영역에 따라서는 차후 한민족의 동질성회복이라는 큰 일을 수행하는 과정에서 치명적인 걸림돌이 될 수 있음에 주목해야 할 것이다. 남ㆍ북한산 식물에 대한 국명의 이질화도 이러한 관점에서 매우 주목되어 마땅하다. 그 까닭은 이름의 혼란이란 그 분야의 교육과 학문발전에 중대한 장애요인이 되기 때문이다. 남한의 경우 한국산 식물에 대한 국명의 통일작업은 아직도 부분적으로 이루어진 정도여서 해결해야 할 난제들이 많지만, 북한의 경우 이미 1970~80년대에 국가적인 주요과업의 하나로 북한산 동, 식물에 대한 국명 통일작업이 완료되어 북한산 식물은 여러 가지 새로운 이름들로 불리워지고 있는 것을 볼 수 있다. 필자는 1992년 과학재단의 방문연구를 통하여 헝가리자연사박물관을 방문하고, 그 곳에 소장된 북한산 식물명집을 입수한 바 있어서, 현재 남한에서 그 명명작업이 완료된 분류군을 대상으로 남북한에 함께 출현하는 식물에 국한시켜 식물명의 비교 검토를 실시하였다. 본 보고는 그 중 하등식물의 조류에 속하는 분류군인 녹조식물과 갈조식물에 대하여 남북한의 국명을 학명과 대비한 것이다. 이와 같은 국명의 비교 검토는 차후 남북한의 식물명 통일작업을 위한 기초자료가 될 것으로 기대한다.