• The Journal of Engineering Geology
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• v.8 no.2
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• pp.115-130
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• 1998

An analysis on landslide types and susceptibilities associated with geomorphic characteristics has been conducted with 916 landslide inventories in Yeonchon-Chulwon District, where two day's heavy rainfall was concentrated on July, 1996. The precipitation during the 2 days, which is equivalent to 0.372 of event cofficient, can cause large landslides based on Olivier's equation. Sliding materials are dominantly composed of debris mixed with rock fragments and soil derived from colluvium and residual soils. 66% of the landslides are belong to debris flow md 23% are due to sediments flow, in accordance with the classification of sliding materials. Most of landslides(> 90%) are small and shallow, less than l00m in length and about 1m in depth, and classified as transitional type. Granite is more susceptible as much as 4.7 times than metamorphic rocks and 2.7 times than volcanic rocks, probably due to higher weathering grade of granite. The highest landslide frequency is concentrated on the areas between 200 and 300m in height and on the slopes between $10-20^{\circ}$ in dgree. More than 50% of landslides occurred under these geomorphic conditions. Consequently, colluviums and residual soils distributed on the gentle slopes are most susceptible to the landslides of the area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.370-377
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• 2018

Currently, Korea is ahead of the forest sector such as forest management, forest investigation and forest management, which is not insufficient compared with the forest advanced countries (Germany, Japan, Austria). However, there is a lack of systematic and advanced forest management plan and related research, and it is not enough to construct GIS for practical and complex analysis. Therefore, in order to perform forest analysis effectively, this study maps forest basic statistics (2010, 2015) based on GIS to map forest information. As a result, the forest area, growing stock, average growing stock, and forest rate could be produced with the maximized visual effect by detailed administrative districts, and systematic analysis of the time series changes was also possible. Forest area increased only in Goseong, Sejong, Cheolwon, Yeoncheon, Daejeon, and Seoul Guro-gu, and decreased in all other areas, while growing stock increased in most areas, Uljin, Ulleung, Seoul Nowon-gu, and Seoul Gangdong-gu. The average growing stock was found to increase in most areas excluding the four administrative districts and the forest rate was higher in 10 regions (Goseong, Yeoncheon, Gongju, Busan Dong-gu, Daegu Seo-gu, etc.) but it decreased in most regions excluding 10 regions. Based on this research, we plan to produce and analyze forest information maps for smaller administrative districts and more.

• Economic and Environmental Geology
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• v.18 no.3
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• pp.277-288
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• 1985

Mineral composition and grain size analyses of the sandstone from the Early Jurassic Daedong Group distributed in Mungyeong, Daecheon, Kimpo and Yeoncheon areas were made for the study of provenances and depositional environments. The most of the analyses are obtained from Mungyeong area, with some preliminarly works from Daecheon, Kimpo and Yeoncheon areas. All sandstones from the study area are characterized by high content of quartz ranging from 59.8 to 87.2 percent of total constituents. Many of quartz which has rounded dust ring seems to come from aeolian sediments. Content of feldspar is very low except Daecheon area where it ranges from 1.8 to 10.0 percent. Sandstones from Mungyeong, Kimpo and Yeoncheon areas are classified as quartz and quartzose arenite/wacke, while those from Daecheon area are classified as quartzose and lithic arenite/wacke. According to the character of the sandstones, provenance could be quartzose sandstone and quartzite. Results of grain size analysis of C-M and sorting versus skewness suggest that depositional environment seems to be fluvial, while log-probability curve pattern lacustrine environment. It is hard to derive a definite conclusion of sedimentary environment by the grain size analysis.

• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.15-26
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• 2007

This study aims to estimate the similarities of lacustrine deposits of lava-dammed Yeoncheon paleo-lake by geochemical analysis such as XRF, ICP-AES, and 14C and OSL age datings in Chugaryeong Rift Valley of Central Korea. OSL age of the lacustrine coastal deposit(YC1) is estimated as 0.11-0.13 Ma. It indicates that paleo-deposits may have remained during at least 20,000 years from 0.13 Ma The origin analysis of deposits were carried out by comparison between lacustrine mud layers($YC1{\sim}2$) and various geomorphic materials of vicinity As a result, the similarity of the origin is highest between the paleo-coastal alluvial deposit of Chatan River(YC8), and surface clay deposit of Jeongok lava plateau(YC9) Next higher similarity is between paleo-lacustrine bottom deposit(YC2) and west valley-side mountain slope colluvial materials(YC5). Another high similarities are among present Chatan River channel sediment(YC7), acustrine coastal deposit(YC1) and east valley-side mountain slope colluvial materials(YC4).

• Korean Journal of Environment and Ecology
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• v.23 no.3
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• pp.239-249
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• 2009

The objective of the study is to examine the perception of the residents in the Civilian Control Zone (CCZ) and the competent local government officials for nature conservation and local development. A survey was conducted on 265 residents as well as 285 government officials from Paju and Yeoncheon Municipals. Both residents and officials perceived the value of biodiversity, natural ecosystem and landscape in the CCZ and seemed to have a sense of pride regarding it. However, they conceived that nature has not been conserved properly and residents in Yeoncheon showed more concern on this matter than residents in Paju. Overall, residents were more devoted to nature conservation or perceived the importance of accordance with nature conservation in local development, which implicates the sound foundation of perception and good prospect for sustainable development in CCZ. Owing to the difference in situation, there was a significant difference in perception between residents and officials. There is a possibility of conflict in Paju because residents desired more local development, whereas officials showed more purpose for nature conservation. In order to achieve simultaneously local development and nature conservation in CCZ, we should pay special attention to studies on living standards of local residents and scientific surveys on natural resources.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.476-491
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• 2017

The water spider (Argyroneta aquatica), a rare member of its species, is one of the few insects known to live under water all over the world. In Korea, the water spider can be found only in the Eundae-ri, Yeoncheon, Gyeonggi province, where they are designated as a natural monument. However, loss of habitat is obvious, as the Eundae-ri wetland undergoes hydrarch succession. Loss of habitat has a direct impact on the water spider population. Thus protective measures for the water spider are needed to preserve the water spider habitat. In this study, a sweeping and visual survey of insect species was conducted in the water spider habitat from May to September 2015. The characteristics of each one of the different insect species and the community features were analyzed in this study. A total of 3,929 insects representing 276 species from 13 orders collected for the analysis. The most frequently collected insects from the Order Hemiptera represented 24.2% of total species and 82.3% of the total number of insects. Community analyses showed dominance, diversity, evenness, and richness indices of 0.23, 2.27, 0.41, and 31.2, respectively. Compared with the previous survey data, these results showed that reduction of the spider's wetland habitat caused the most commonly collected insects to adapt and spread to the surrounding terrestrial environment.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.25-25
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• 2019

1953년 7월 27일 정전협정 이후 한반도를 가로지르는 DMZ (Demilitarized zone: 비무장지대)가 설정되었다. DMZ에 출입은 군사정전위원회의 허가가 있어야 가능하기에 군사시설 및 군작전지역을 포함하여 DMZ 및 민간인통제선 이북은 민간인 접근의 제한으로, 단절된 공간으로 변모하였다. DMZ는 우리나라의 대표적인 동고서저의 지형 및 다양한 생태환경을 두루 갖추고 있어 중요한 생태적 요충지로 평가받고 있다. 산림지역은 민간인통제지역까지 합치면 40여개의 산지가 분포하고 있으며, 하천은 크게 15개의 크고 작은 하천이 위치하고 있다. 남방한계선 수계를 따라 일부지역들은 하천 배후습지, 묵논습지 등 습원형태로도 많이 발견되고 있다. 이런 습원지역들은 대부분 미확인 지뢰지대로 접근이 제한적인 만큼 지난 세월의 흔적들을 고스란히 담고 있다. 1965년 한국자연보존연구회는 30여명의 국내학자를 동원하여 서울에서 가까운 DMZ 인접지역에 대한 예비적인 학술조사를 실시하였으며, 이를 계기로 1966년 10월부터 1968년 9월까지 2년간에 걸쳐 한국자연보존위원회 34명의 국내학자와 미국 스미소니언연구소(Smithsonian Institution) H. K. Buechner 박사를 대표로 5명의 국외학자가 공동으로 종합적인 학술조사를 수행하였다. 이는 DMZ 연구의 시작을 알렸으며, 이후 남북관계나 시대여건에 맞추어 간헐적으로 다양한 조사 및 연구들이 이어져오고 있다. 2015년부터 2018년까지 DMZ 철책주변 현장조사를 통해 확인된 식물현황은 964분류군이다. 군시설로 인해 식물서식환경이 제한적인 상황이지만 척박한 환경에 적응하고 있는 식물은 다양하다. DMZ와 맞닿아 있는 7개 지역에 대한 식물현황은 철원 638분류군, 연천 631분류군, 양구 525분류군 순으로 나타났다. 대부분 중동부 지역에 높은 식물종수가 나타났으며, 서부와 동부의 식물들이 고르게 나타나는 결과로 보인다. 큰잎쓴풀, 봉래꼬리풀 등 희귀식물도 있는 반면, 잠재적으로 생태계에 영향을 줄 수 있는 침입외래식물도 다수 포함되어 있어서, 지속적인 모니터링 및 관리가 필요하다. 그 중에서도 양구지역에 새롭게 발견된 Macleaya cordata (Willd.) R.Br.(양귀비과)는 독성이 포함된 식물이며, 인제에서 2014년에 발견된 미역취아재비는 DMZ일원에 제한적으로 분포하는 종이였으나 현재 연천에서 발견되는 등 확산에 대한 관리방안이 필요하다.

• 한국문화재보존과학회:학술대회논문집
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• 2005.11a
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• pp.207-212
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• 2005

• Economic and Environmental Geology
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• v.27 no.1
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• pp.29-39
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• 1994

Gabbroic rocks in which titanomagnetite orebodies are embedded were emplaced in Precambrian metasedimentary rocks. Hornblende K-Ar ages for equigranula and gneissic gabbros were obtained to be $1021.8{\pm}14.5$ Ma and $1468.4{\pm}20.8$ Ma, respectively. Biotite-granite has an age of 116.4 Ma, which has corresponded to Daebo granite. Amphibole minerals of the gabbroic rock and the magnetite orebodies belong to calcic amphibole group such as ferroan pargasite, pargasite, and ferro-pargasite. The gabbroic rocks have unusually high content of $TiO_2$ ranging from 0.88 to 6.03 wt.% with an average value of 3.46 wt.% as compared to normal gabbroic rock with 1.32 wt.% in $TiO_2$. Incompatible elements such as Ba and Sr of the gabbros are negatively correlated with $SiO_2$. In contrast, Co and Cr have a positive correlation with $SiO_2$, suggesting a normal differentiation trend of gabbroic magma.

• Journal of Korea Water Resources Association
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• v.32 no.1
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• pp.49-59
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• 1999

In order to understand the present situation of bridge scouring and to provide the fundamental information for bridge design, in-situ measured data is analyzed for bridge scours at small and medium streams in the heartland of Korea. The physical parameters affecting the bridge scouring such as flow depth, velocity, pier length and width, scouring depth, and the angle between flow and pier are extensively surveyed and measured. According to the locality and the pier type data are classified to analyze. With these data, some important factors for the scour depth such as flow depth, angle and Froude number are investigated and applied to existing formulas proposed by many researchers. In addition, the computational results are compared with the measured and some of the applicable formulas in this region are recommended.