• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.192-204
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• 2013

Fish community structure and inhabit status of endangered fish species were investigated during April to November 2011 in Baebong Stream, Gangwon do, Korea. The number of fish species inhabiting the upper section (Stations 1~3, 5) was 14 and the stream bottoms were mostly composed of cobbles and boulders (Aa-type). Meanwhile, the number of fish species inhabiting the lower section (Stations 4, 6, 7) was 26 and the stream bottoms were mostly composed of pebbles, cobles and sand (Bb-type). A total of 26 species belonging to ten families were found in the stream during the survey period. The dominant and subdominant species were Rhynchocypris steindachneri (31.1%) and Squalidus multimaculatus (13.3%), respectively, and others such as Pungitius kaibarae (11.0%), Zacco koreanus (7.8%), Misgurnus anguillicaudatus (7.0%), Iksookimia pacifica (5.5%) and Z. platypus (5.3%) were followed in the order. Four species of Squalidus multimaculatus, Z. koreanus, I. pacifica and Liobagrus andersoni were endemic to Korea. And, Lethenteron japonica, L. reissneri, Pungitius sinensis and Cottus hangiongensis were endangered fish species in this stream. Oncorhynchus keta, L. japonica and Tribolodon hakonensis were anadromous species, and Plecoglossus altivelis was an amphidromous species. The similarity index based on species composition and abundance clearly divided the fish community structure of the Baebong Stream into two sections fragmented by a weir installed into the stream. It is necessary to install a fish ways on the weirs for a fish migration and movements.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.47-47
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• 2018

붉가시나무는 기후변화에 따라 분포 확산이 예측되고 목재로서의 이용가치가 증가하고 있다. 본 연구는 국내에서 붉가시나무의 자원량 및 생육환경을 파악하기 위하여 국내 분포 및 자생지의 식생구조를 분석하였다. 분포 범위 조사 결과, 제주도를 비롯한 남해안의 도서지역에 주로 분포하는데, 제주도 남부지역 약 200~800m에 분포하며 가거도, 완도, 진도 등에 주로 분포하였다. 지역별 자생지의 입지분석 결과, 교목층의 수고는 제주도에서 17.3m로 가장 높고 가거도의 경우 11.3m로 가장 낮았다. 또한 가거도 자생지의 경우 노출암 비율 70.7%, 평균 경사도 약 $30^{\circ}$로 경사가 매우 급하고 토양층이 가장 빈약하였다. 반면, 제주도에서는 계곡 사면이나 완만한 경사의 산록지대에 주로 분포하였다. 자생지의 식생구조를 파악하기 위하여 수종별 평균중요도지수를 산출한 결과, 교목층에서는 붉가시나무가 가장 높았다. 아교목층의 평균중요도지수는 제주도, 완도, 진도 자생지의 경우 동백나무가 각각 150.93, 83.54, 91.38로 가장 높았는데 이는 동백나무의 밀도가 상대적으로 높았기 때문이다. 반면 가거도 자생지에서는 붉가시나무의 평균중요도지수가 66.55로 가장 높게 산출되었다. 자생지 내 수종의 흉고직경에 따른 수고의 분포는 제주도, 진도, 완도 자생지의 경우 붉가시나무와 기타 수종이 전체 층위에서 고르게 분포하였지만 가거도 자생지에서는 상층일수록 경쟁 종없이 단일종이 분포하는 단순림으로 나타났다. 이 같은 단순림에서는 일시적인 교란에 의해 상층 개체가 없어지면 안정적으로 후대 개체를 생산할 수 없기 때문에 숲 가꾸기와 같은 적극적인 조절이 필요한 것으로 판단된다. 종다양도지수 분석결과, 층위가 높을수록 균재도가 낮게 나타났다. 이와 같은 연구결과는 붉가시나무림의 조성이나 안정적 유지 등 인위적 조절을 위한 기초 자료로 활용 할 수 있을 것으로 판단된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.285-294
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• 2005

The behaviors of the ground in crossed zone and the existing upper tunnel in shallow cover due to the excavation of new lower tunnel crossed to that was studied. Model test was performed in the large scale test pit, the size was '$4.0m(width){\times}3.8m(height){\times}4.1m(length)$'. Test ground was constructed uniformly by sand in middle density and test with the crossed angle of $56^{\circ}$ (obliquely) were performed. The numerical analysis was performed on equal condition with model test. Results of the study by model test and numerical analysis show that earth pressure and settlement of the ground in crossed zone were redistributed due to the longitudinal arching effect by the excavation of lower tunnel. Model test shows that upper tunnel blocks stress flow due to the longitudinal arching effect by excavation of lower tunnel.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.465-469
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• 2018

여울과 소는 하천의 물리적 특성(경사, 하상재료, 지질의 형태)에 따라 자연적으로 형성되며, 이에 따라 하도 지형이 다양하게 변화하고 생물의 서식처의 다양성이 확보됨으로써 하천의 생태환경에 긍정적인 영향을 미친다. 우리나라의 경우 하천주변의 충적평야에서 벼농사가 이루어지므로 아주 많은 농업용 취수보가 설치되어 있으며, 또한 하상경사가 급하므로 하상안정을 위하여 낙차공 등의 하상유지공도 상류에 많이 설치되어 있는 실정이다. 취수보 및 하상유지공 등의 하천횡단구조물은 하상의 종적 연속성을 단절시키고, 상류측에 대규모의 정체수역을 형성함으로써 하도의 자연적인 여울-소 지형특성을 훼손함과 더불어 흐름 다양성을 단순화시킨다. 이러한 하천횡단구조물의 부정적 영향은 수서동물의 이동통로를 차단할 뿐 아니라 수서동물의 서식처를 단순화함으로써 생태계에 부정적 영향을 미쳐서 생물종의 다양성을 훼손하는 심각한 문제를 초래하고 있다. 본 연구에서는 하천횡단구조물이 여울-소의 형성에 미치는 영향을 규명하기 위하여 경상남도의 하천 중 유역면적이 $100km^2$ 이상인 하천 중에서 하천횡단구조물의 영향을 받는 하천의 구간과 하천횡단구조물의 영향을 받지 않는 하천의 구간을 분류하여 하천횡단구조물이 여울-소에 미치는 영향을 분석하였다. 하천횡단구조물이 여울-소 형성에 미치는 영향을 하상경사에 따라 구분하였으며 그에 따라 하천횡단구조물이 여울에 미치는 영향을 비교하였다. 상류에는 배수위의 영향으로 정체수나 인위적인 평여울이 발생하며, 하류에는 낙차로 인하여 소나 여울이 발생하지만, 그 빈도는 하천횡단구조물의 설치 간격에 따라 자연상태에서 보다는 현저히 낮게 나타났다. 경남 지방에서 유역면적 $100km^2$ 이상인 30개 하천 중에서 16개의 하천에 설치된 하천차단시설물은 보 405개소와 낙차공 129개 총 534개를 조사하였으며, 하천차단시설물의 설치간격 및 높이가 여울-소의 형성에 가장 큰 영향을 미친다는 사실을 확인하였다.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1425-1434
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• 2021

Continuous and periodic data acquisition must be preceded to maintain and manage the river facilities effectively. Adapting the existing general facilities methods, which include river surveying methods such as terrestrial laser scanners, total stations, and Global Navigation Satellite System (GNSS), has limitation in terms of its costs, manpower, and times to acquire spatial information since the river facilities are distributed across the wide and long area. On the other hand, the Mobile Mapping System (MMS) has comparative advantage in acquiring the data of river facilities since it constructs three-dimensional spatial information while moving. By using the MMS, 184,646,009 points could be attained for Anyang stream with a length of 4 kilometers only in 20 minutes. Levee points were divided at intervals of 10 meters so that about 378 levee cross sections were generated. In addition, the waterside maximum and average slope could be automatically calculated by separating slope plane form levee point cloud, and the accuracy of RMSE was confirmed by comparing with manually calculated slope. The reference slope was calculated manually by plotting point cloud of levee slope plane and selecting two points that use location information when calculating the slope. Also, as a result of comparing the water side slope with slope standard in basic river plan for Anyang stream, it is confirmed that inspecting the river facilities with the MMS point cloud is highly recommended than the existing river survey.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.231-238
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• 2012

The rockbolt functions as a main support, which restricts enlargement of the plasticity area and increases stability in the original ground around tunnels, and prevents a second deformation of an excavated surface by supplementing vulnerability arising from opening of the excavated surface. System bolting is generally applied if ground conditions are bad. System bolting is generally installed perpendicular to the excavation direction in every span. If a place is narrow, or it is difficult to insert bolts due to construction conditions, it may be connected and used with short bolts, or installed obliquely. In this study, laboratory model tests were performed to analyze the effect of the ground being reinforced by inclined bolts, based on a bending theory that assumes that the reinforced ground is a simple beam. In all test cases, deflections and vertical earth pressures induced by overburden soil pressure were measured. Total of 99 model tests were carried out, by changing the installation angle of bolts, lateral and longitudinal distance of bolts, and soil height. The model test results indicated that when the installation angle of bolts was less than $75^{\circ}$, deflections of model beams tended to increase rapidly. Also, the relaxed load that was calculated by earth pressure was rapidly increased when the installation angle of bolts was less than $75^{\circ}$. However, the optimum installation angle of inclined bolts was judged to be in the range of $90^{\circ}{\sim}75^{\circ}$. Also, as might be expected, the reinforcement effect of bolts was increased when the longitudinal and lateral distance of bolts was decreased.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.188-198
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• 2015

This study was conducted in order to investigate the distribution pattern of weeds and ecological characteristics on the dry field in the Eastern region of Korea. The weed species data were obtained from 12 regions in Gangwon-do and Gyeongsang-do. 150 taxa were recorded from three main distinguished habitats; inside of dry field (IDF), embankment around the end of dry field (EDF), levee slope of dry field (LS). The weed species of three different habitats were IDF 83 taxa, EDF 133 taxa and LS 105 taxa. The species showing higher rNCD value was Portulaca oleracea in IDF, Digitaria sanguinalis in EDF and Humulus japonicus in LS. Compositae was dominant family followed by Gramineae, Polygonaceae and Leguminosae. Life form was distinguished as Th-R5-D4-e and three different habitats showed the same results. Disturbance index was analysed as IDF 83.1%, EDF 68.4%, and LS 62.9%. Naturalized rate was analysed as IDF 28.9%, EDF 22.6%, and LS 20.0%. These results indicate that the weeding management, land use intensity, and human interference effect on the distribution index and naturalized rate of weed.

• Journal of the Korean Geotechnical Society
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• v.35 no.5
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• pp.21-30
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• 2019

While the study of the shallow tunnel has been mainly on the longitudinal load transfer and horizontal surface conditions, the study of the ground behavior of shallow tunnel under the slope is not sufficient. Therefore, in this study on the ground behavior around a tunnel due to the sidewall deformation of shallow tunnel under the slope that is excavated in longitudinal direction, a scale-down model test has been performed. The model tunnel has the dimension of 320 mm wide, 210 mm high and 55 mm long with enough material strength in aluminum and the model ground has the uniform ground conditions by 3 types of carbon rods. The model test has been performed with the variables of slopes and the cover depths by controlling the tunnel sidewall deformation, and the change of sidewall-load, load transfer, ground subsidence was monitored and analyzed. According to the increase of the slope, the maximum ground subsidence increased by 20~39% compared to the horizontal surface. The load ratio increased by maximum 20% in the tunnel crown and decreased in sidewall according to the surface slope. The load transfer shows maximum 128% of increase at the cover depth of 1.0D, while at the 1.5D cover depth it shows non-critical difference from horizontal surface. The slope has major effects on load transfer at the cover depth of 1.0D.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.151-157
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• 2003

This research was conducted to investigate about structural characteristics of vegetation by change of the environmental factors for prolific open-pollinated progeny forest in Pinus koraiensis stands. Stand slope of Kapyung area was slower than Youngdong area. On the other hand, contents rate of the soil chemical properties in Kapyung was lower than Youngdong area. And relative intensity of light was higher Youngdong than Kapyung area. On the whole, growth of the Pinus koraiensis was more dominant Kapyung area than Youngdong. Analysis result of the relative density, - frequency, - coverage and importance value to shrub layer in each local stands, Quercus mongolica and Quercus acutissima were dominant species in Kapyung area. Dominant species In Youngdong area was Quercus acutissima. In Kapyung area, appearance species of the vegetation layer was consisted that live in moist soil and shaded lot. Youngdong area showed fewer species than Kpyung area. Species diversity of shrub and vegetation layer in Kapyung and Youngdong area was higher than Youngdong. This result was judged by slope difference between each areas. Kapyung area need enforce thinning and Youngdong area conduct tending management on shrub layer.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.4
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• pp.495-503
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• 2001

In a functionally graded materials(FGM), two constituent material particles are mixed up according to a specific volume fraction distribution so that its thermoelastic behavior is definitely characterized by such a material composition distribution. Therefore, the designer should determine the most suitable volume fraction distribution in order to design a FGM that optimally meets the desired performance against the given constraints. In this paper, we address a numerical optimization procedure, with employing interior penalty function method(IPFM) and FDM, for optimizing 2D volume fractions of heat-resisting FGMs composed of metal and ceramic. We discretize a FGM domain into finite number of homogenized rectangular cells of single design variable in order for the optimization efficiency. However, after the optimization process, we interpolate the discontinuous volume fraction with globally continuous bilinear function in order to enforce the continuity of volume fraction distributions.