• The KIPS Transactions:PartB
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• v.14B no.6
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• pp.423-430
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• 2007

Optical coherence tomography(OCT) is a high resolution imaging system which can image the cross section of microscopic organs in a living tissue with about $1{\mu}m$ resolution. In this paper, we implement OCT system and acquire 2-D images of rat eye and human molar samples especially in the field of opthalmology and dentistry. In terms of 2-D images, we reconstruct 3-D OCT images which give us another inner structural information of target objects. OPEN-GL reduces the 3-D processing time 10 times less than MATLAB.

• The Korean Journal of Quaternary Research
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• v.12 no.1
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• pp.99-109
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• 1998

유성구 장대동 지역의 홀로세 하성퇴적층에서 보존 상태가 양호한 화분, 포자가 풍 부하게 산출되었다. 이들 미화석산출을 근거로하여 두 개의 화부대가 설정되었다. 제 I 화분 대는 낙엽성활엽수의 목본화분이 풍부하게 산출괴며 반면에 초본화분은 상대적으로 빈약한 상태로 산출되는 것이 특징이다. 제 II화분대는 초본화분 중 벼과(재배종)화분이 우점으로 산출되며 소나무속도 비교적 풍부하게 산출되는 반면 낙엽성활엽수의 목본화분은 빈약하게 산출되는 것이 특징이다. 시대설정은 인접한 지역에서 화분분석과 함께 절대연령측정이 수 행된 기존의 연구자료와 비교하여 이루어졌다. 따라서 제 I화분대는 1,500 year B.P 이전 제 II화분대는 1,500 year B.P∼현재를 나타낸다. 제 I화분대에서는 인간간섭의 영향을 받기 전 인 자연식생관계를 나타내지만 제 II화분대에서는 농경과 벌목이 본격적으로 시작된 시기로 나타났다, 기후조건은 제 I화분대 동안은 온난한 온대의 습한 환경이었고, 제 Ii화분대 동안 은 현재와 비슷한 한랭한 온대의 습한 환경이었던 것으로 판단된다, 인간의 정착과 농경생 활의 시기에 대한 해석에 있어서 화분분석자료와 고고학자료가 서로 잘 일치하는 것으로 본 연구에서는 나타났다.

• Korean Journal of Environment and Ecology
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• v.24 no.5
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• pp.566-574
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• 2010

This study was carried out for the purpose of understanding the situation of the urban forest and presenting basic data bases for a proper management plan through the analysis of forest vegetation and soil characteristics. In three representative urban forests of Deajeon, we analyzed the differences of vegetation and soil properties in each geological location. The indices of ecological health such as Species Diversity and Maximum Species Diversity are increasing in the order of Namseon Park, Wolpyung Park and Mt. Bomun; the first is in the center of the city, the second is well-conserved inner-city park and the third is in the border of the city. In the soil analysis of Namseon Park where human disturbance is strong, the surface fuel bed was very thin just 0.5cm and the soil was harder than the other two urban forests, the soil hardness was $0.5{\sim}3.7kg/cm^2$. All three urban forests showed low $pH_{1:5}$ under 5.0 except Robinia pseudo-acasia association of Wolpyung and low exchangeable cation level. These results say that the urban forests of Deajeon have been being acidified severely and the eluviation of exchangeable cation is proceeding. The organic matter and the available phosphate level was lower than the average level of Korean forest. It means that nutrition supply is not sufficient. In Daejeon urban forests, the management plan of urban forest is necessary according to the analysis result of vegetation and soil.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.454-461
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• 2015

This study aims to classify the biotope types based on the vegetation community in built-up areas by different land use and to map the plant communities. By classifying biotopes according to a taxonomic system, the characteristics of a biological community can be well-represented. The biotope classification indexes for the target area include human behavioral factors such as land use intensity, land-use patterns and land-cover types. The type classification was divided into four hierarchic ranks starting with Biotope Class, next by Biotope Group and Biotope Type and lastly by Biotope Sub-Type. The Biotope Class was first divided into two areas: the areas improved by humans and the areas unimproved by humans. The improved areas were again divided into permeable and non-permeable regions on the Biotope Group level. In the Biotope Type level, permeable paving areas were divided into areas with wide gap pavers and those with narrow gap pavers. The differential species of each biotope type are Lindera glauca, Conyza canadensis, Mazus pumilus, Vicia tetrasperma, Crepidiastrum sonchifolium, Zoysis japonica, Potentilla supina and Festuca arundinacea. The results of this study suggest that the biotope classification methodology, using a subjective phytosociological approach, is a useful and valuable tool and the results also suggest the possibility of applying more objective and scientific methods in mapping and classifying various environments.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.26-30
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• 2002

Purpose: To estimate the initial and early phase fixation power of the human bone interference screw in reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone allograft. Materials and Methods: The results of twenty eight knees of reconstruction with bone-patellar tendon-bone allograft were analysed in 6 weeks, 12 weeks, 6 months and one year following operation. Physical examination including Lachman test, flexion rotation drawer test and jerk test were performed. The KT-1000 measurement was performed at the same time. In Lachman test 0 $\~$2mm anterior displacement of the tibia was considered normal. The KT-1000 measurement of normal side was compared with operation side and the difference of the two was recorded. The MRI was checked at final follow-up. Results: All but one knee showed normal in physical examination. The failed case showed proximal migration of the graft due to insufficient number of interference screw fixation in widened tibial tunnel. Conclusions: The human cortical bone interference screw showed sufficient initial and early phase fixation power in reconstruction of the anterior cruciate ligament.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.1
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• pp.26-33
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• 2001

Thrust vector control system is control device which is mounted exit of the nozzle to generate pitch, yaw and roll directional force by deflecting flow direction of the supersonic jet from the nozzle. By obtaining control force, jetvane which is exposed in jet flow is working thermal and aerodynamic load. Axial thrust loss and side thrust is affected by shock patterns and interactions between jetvanes according to jetvane geometry and turning angle. In this study, we designed 6 types of jetvane to evaluate pitch, yaw and roll characteristics of ietvane in supersonic flow, and perform the cold flow test in range of turning angles of jetvanes between $0^{\cire}$ and $25^{\cire}$ by $5^{\cire}$ respectively. Also, calculation is going side by side to analyse flow interaction. Results show that there is no interactions between jetvanes upto turning angle 20$^{\circ}$, chord and lead length ratio is very important parameter to aerodynamic performance and maximum thrust loss is appeard to 17% of axial thrust in roll directional control.

• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.33-48
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• 2000

Vegetation disturbance history of the Korean Peninsula from the Palaeolithic Age to the Koryo Dynasty (1392) has reconstructed by the use of various data sources. Active vegetation disturbance, which has begun during the Neolithic Age, seems to be more widespread on lowland and coastal areas in the early stages, but later expanded into inland areas. The ploughing of a field and the selective cutting of certain trees, such as oak trees, nettle trees and pine trees are noticeable, and eventually caused deforestation during the Bronze Age. The use of iron tools of the Iron Age has enabled the forest clearing to develope the dry fields. During the Three Kingdoms period (BC 57∼AD 918) extensive deforestation has maintained for the development of cultivated fields, as well as other activities, such as timber, lumbering, production of iron farm implement, ploughing by cattle. The encouragement of disafforestation on mountain slope and creation of terraced field during the Koryo Dynasty (918∼1392) has caused the deforestation over the country, along with the consumption of large amount of wood and timber for fire-wood, ship-building, mining, xylography and so on.

• Korean Journal of Environment and Ecology
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• v.10 no.2
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• pp.171-183
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• 1997

Diversity, abundance, species distributions and distributions of two strategists (specialist and geceralist) of butterflies were investigated monthly from June 1996 to Oct. 1996 by line transect method in the Chunbul-dong valley from park gate to Yangpok Sanjang. The butterfly faunas of the eight regions in Kwangwon province, Gyunggi proavince and Pusan were also studied by the same method to assess diversity and abundance of butterfly community in the study region. The 18 butterfly species in 7 families were found in this study and the 48 butterfly species in 7 families were distributed in the study area from thes study and the other researches. The 30 butterfly species reported in the other studies were not found in this study and Kaniska canace L. of them would be to decrease in density. In the study area, the common species were Artogeia melete M., Neptis sappho P. and Libythea celtis F.. The representative Korean common butterflies such as Artogeia rapae L., Colias erate E. and Papillio xuthus L. were rare. The PCA(Principal Component Analysis) ordinations indicate that habitat disturbance by human would be major factor for butterfly community and species distribution. Difference was not found in diversity according to habitat disturbance. Abundance, however, was higher in the disturbed region than the undisturbed region. Compared with the other regions, abundance was greatly lower and diversity was slightly lower than that of the other regions. Two strategists exhibited different distribution patterns. Generalists were found more commonly in the disturbed region and widely distributed in both of the disturbed region and the undisturbed region than specialists.

• Korean Journal of Environment and Ecology
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• v.15 no.3
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• pp.247-256
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• 2001

The purpose of the present study is to prepare the conservation category to establish the Natural Ecosystem Conservation Area(NECA) in Korea. The authors prepared the conservation category for the NECA based on the previous relevant papers and reports. This draft of conservation category was examined by way of the case study. From this, the possible factors are introduced to prepare the final conservation category that can be applied directly in Korean situation for the conservation of natural areas. The present conservation category was prepared based on the possible data, while some factors of which do not possess the adequate raw data at the moment was removed. According to the reference analyses from the previous conservation categories reported in order to prepare the conservation category in the NECA, a total of 27 factors was assessed; 21 for rarity and 15 fur utility and diversity, 13 far size, for both naturalness and human influence, 13 for typicalness 12 and 10 for fragility. From the literature reviews, the categories which quantitatively assessed was 13: 9 for rarity, 8 far human influence, and 5 for size. From the 27 conservation categories assessed, the factors such as rarity, taxonomic distinctiveness and threat was regarded as applicable to the Korean situation. Furthermore, the criteria such as use could be applied further when this is supported by the augmentative research and field studies.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.618-638
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• 2018

This study examined the vegetation structure in the ridge of the Hannamgeumbuk-Jeongmaek and Geumbuk-Jeongmaek by selecting 7 sites(2 sites at Hannamgeumbuk-Jeongmaek and 5 sites at Geumbuk-Jeongmaek) in consideration of the environmental conditions and artificial influences and conducting the vegetation survey in the selected sites. The community classification based on TWINSPAN categorized the vegetation at Hannamgeumbuk-Jeongmaek into 8 groups: Quercus variabilis-Q. acutissima community, Pinus densiflora-Q. mongolica community, Pinus densiflora community, P. densiflora-Q. mongolica-Q. variabilis community, P. densiflora-Deciduous oaks community, P. koraiensis community, Q. mongolica-Q. variabilis community, and Larix kaempferi-P. koraiensis community. It also categorized the vegetation at Geumbuk-Jeongmaek into 9 groups: Quercus variabilis community, Deciduous broad-leaved community, Q. mongolica community, Pinus densiflora-Q. mongolica-Q. variabilis community, Q. acutissima community, P. densiflora-Q. acutissima-Q. variabilis community, P. densiflora-Q. mongolica-P. rigida community, P. densiflora-P. thunbergii-Deciduous oaks community, and P. koraiensis community. Two species, Quercus mongolica and Pinus densiflora, which are widely distributed in the ridges of the Jeongmaeks and Baekdudaegan in South Korea, were dominant in many of the surveyed sites. The appearance of planted Castanea crenata in some plots, although not in high population, suggests human intervention in most regions of the Hannamgeumbuk-Jeongmaek and Geumbuk-Jeongmaek in the past. The Gayasan area, which is part of the Geumbuk-Jeongmaek and where the maritime climate and continental climate overlap, showed Pinus thunbergii, reflecting the local climate characteristics.