• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.166-178
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• 2006

Recently, the frequency of occurring dynamic events such as earthquakes, explosives blasting and other types of vibration has been increasing. Besides, the chances of exposure for rock discontinuities to free faces get higher as the scale of rock mass structures become larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, artificially fractured rock joint specimens were prepared in order to examine the dynamic frictional behavior of rough rock joint. Roughness of each specimen was characterized by measuring surface topography using a laser profilometer and a series of shaking table tests was carried out. For mated joints, the static friction angle back-calculated ken the yield acceleration was $2.7^{\circ}$ lower than the tilt angle on average. The averaged dynamic friction angle for unmated joints was $1.8^{\circ}$ lower than the tilt angle. Displacement patterns of sliding block were classified into 4 types and proved to be related to the first order asperity of rock joint. The tilt angle and the static friction angle for mated joints seem to be correlated to micro average inclination angle which represents the second order asperity. The tilt angle and the dynamic friction angle for unmated Joints, however, have no correlation with roughness parameters. Friction angles obtained by shaking table test were lower than those by direct shear test.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.79-90
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• 2017

Urban environment represent one of the most dynamic regions on earth. As in other countries, forests, green areas, agricultural lands are rapidly changing into residential or industrial areas in South Korea. Monitoring such rapid changes in land use requires rapid data acquisition, and satellite imagery can be an effective method to this demand. In general, SAR(Synthetic Aperture Radar) satellites acquire images with an active system, so the brightness of the image is determined by the surface roughness. Therefore, the water areas appears dark due to low reflection intensity, In the residential area where the artificial structures are distributed, the brightness value is higher than other areas due to the strong reflection intensity. If we use these characteristics of SAR images, settlement areas can be extracted efficiently. In this study, extraction of settlement areas was performed using TerraSAR-X of German high-resolution X-band SAR satellite and KOMPSAT-5 of South Korea, and object-oriented image classification method using the image segmentation technique is applied for extraction. In addition, to improve the accuracy of image segmentation, the speckle divergence was first calculated to adjust the reflection intensity of settlement areas. In order to evaluate the accuracy of the two satellite images, settlement areas are classified by applying a pixel-based K-means image classification method. As a result, in the case of TerraSAR-X, the accuracy of the object-oriented image classification technique was 88.5%, that of the pixel-based image classification was 75.9%, and that of KOMPSAT-5 was 87.3% and 74.4%, respectively.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.3
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• pp.102-118
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• 2010

Since hills are transitional area between plains and mountains, they are always under pressure to be developed. In the past, hills were recognized as areas that can be developed easily, but in the present they should be considered and preserved as forest resources. So far, little research has been done regarding cultivation status and transitional procedure. This study attempts to quantify changes in land use using time series data. To do so, this study has created a land use map for 1915, 1972, 2002 and 2006, and conducted a spatial analysis based on GIS. The research areas(the total size of the hills are 3,034 ha) are located in Chungcheongnam-do of South Korea. The size of the forest area of the hills in the research zone has decreased by 50% during the period of 1915 to 2006. The size of the reduced forest area after 2002 is similar to size of the reduced area that had taken place for the last 30 years before 2002. The reduction in forest area in the research area has led to increases in paddy field, upland field, artificial structures, and bare land. From 1915 to the late 1980s, hill development had been related to the primary industry and after the late 1980s, it has associated with the development of the secondary industry including industrial complex.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.149-162
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• 2010

The most serious problem in oil stockpiles with artificial underground cavern is maintaining the stability of ground water system. In order to understand the ground water system around K-1 site, we determined the regional flow direction and level distribution of groundwater, and investigated the major geologic factors influencing their flow system. Reactivated surface along the contact between granite and gneiss, and fractures and faults along the long acidic dyke may contribute as important pathways for groundwater flow. Within K-1 site, groundwater level fluctuation is closely related to the rainfall events and injection from surface or influx water. In this project, the effect of groundwater pumping from the southern wells was examined. Based on equations relating water level drawdown to pumping rate at those wells, their pumped outflow of groundwater ranged from $80\;m^3$/day to less than $250\;m^3$/day. The modeling results with MODFLOW imply that the previous groundwater pumping at distance of 1.2 km may not affect the groundwater level variations of the K-1 site. However, continuous pumping work at quantity over $250\;m^3$/day in this area will be able to affect the groundwater system of the K-1 site, particularly along the acidic dyke.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.307-314
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• 2016

River restoration has recently been performed not only for the improvement of the artificial parts in the past but also for the restoration of abandoned river reaches which were blocked and isolated. For the restoration of abandoned river reaches, it is important to recover the hydraulic and ecological connectivity in the isolated space by longitudinal structures like levees. But because the assessment tools to determine whether the river restoration is performed properly are so rare at present, we aim to provide a tool for assessing ecological connectivity in a target river in this study. In the first step, one-dimensional numerical model for rainfall-runoff and channel routing was developed and then applied to the watershed of the Cheongmi Stream. In this step, a numerical model was developed to assess the restoration of connectivity. The model consists of two parts: one part is to convert the results of one-dimensional channel routing into two-dimensional spatial distribution. The other is to calculate the habitat suitability index according to time steps by using two-dimensional hydraulic features. The model was applied to a restoration area of the Cheongmi Stream. The advantage of this study is that two-dimensional hydraulic analysis can be easily obtained from one-dimensional hydraulic analysis without a complex and time-consuming two-dimensional analysis. HHS (Hydraulic Habitat Suitablility) by sections of target reaches and target species can be easily obtained using the results of this study.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.361-371
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• 1990

The present observations were focussed mainly on the morphological findings of the utero-vaginal(U-V) glands in normal laying domestic hens and the storage of cock spermatozoa in the U-V glands at various times after artificial insemination(AI). These domestic hens were assigned to three group of PMS-treated, GnRH-treated before last AI, and control group. The hens were sacrified at intervals of 1,3,7,12 and 19 days after AI. Histological sections of U-V junctions were prepared and the morphological structures of the U-V glands were observed and then were scored about the spermatozoa presence in the U-V gland. 1. The U-V glandular tubules were mostly unbranched with single columnar epithelium. Also these tubules were occassionally observed as one circular-rotated tubules or 2 to 3 branched convoluted tubules in special shapes. The numbers of the convoluted curves per tubule were $4.3{\pm}3.3$ and the ranges of convoluted curve number were straight to 16 curves. 2. The inside and outside diameters of the glandular tubules were $6.5{\pm}3.5{\mu}m$, and $35.2{\pm}4.7{\mu}m$, respectively, and the tubular lengths of the U-V glands were $219.3{\pm}115.7{\mu}m$. 3. Storaged spermatozoa in the U-V glands of all three group hens were intensively stained by hematoxylin, and packed in tight, longitudinally parallel bundles within the tubules. In addition, numbers of completely spermatozoa-filled glands were tend to increase or decrease in proportion to the numbers of partially spermatozoa-filled glands. Also U-V glands containing spermatozoa tend to be present collectively in the any zone of U-V junction. 4. In the control group, the numbers of glands containing spermatozoa in the hens at 1,3,7,12, and 19 days after AI were found to be 22.9, 33.3, 35.8, 8.6, and 0% respectively. 5. In the PMS-treated group, the numbers of glands containing spermatozoa in the hens at 1,3,7,12, and 19 days after AI were found to be 33.6, 29.7, 26.8, 8.2 and 0% respectively. 6. In the GnRH-treated group, the numbers of glands containing spermatozoa in the hens at 1,3,7,12, and 19 days after AI were found to be 19.7, 40.8, 20.4, and 0% respectively.

• Journal of the Korean Wood Science and Technology
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• v.17 no.4
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• pp.1-25
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• 1989

가죽나무 (Alianthus altissima Swingle) 수간(樹幹)의 지항고(地上高) 180cm 부위(部位)에 19mm 너비의 플라스틱 밴드를 결체(結締)하여 1년간(年間) 방치(放置)한 후 이 밴드를 결체(結締)하여 주므로써 수가(樹幹)을 둘러싸는 원반형태(圓盤形態)의 과대(過大)한 비대생장(肥大生長) 조직(組織)인 종양상조직(腫瘍狀組織)(tumorous tissue)이 형성(形成)되고 이러한 종양상(腫瘍狀) 조직(組織)의 원반(圓盤)과 상하(上下)에 위치(位置)한 정상형태(正常形態)의 원반(圓盤)을 채취(採取)하여 해부학적(解剖學的) 차이(差異)를 조직학적(組織學的) 특성(特性)면에서 조사(調査) 비교(比較)하였다. 종양상(腫瘍狀) 부위(部位)에서는 이상적(異常的)으로 넓은 연륜폭(年輪幅)을 지니는 중양재(腫瘍材)(tumor wood)가 밴드 해체(解締) 다음 해인 제(第)3연륜(年輪)에서 형성(形成)되었으며 밴드 결체기간(結締期間)중에 생장(生長)한 제(第)2연륜내(年輪內)에서는 내부(內部)로 발달(發達)된 변색재(變色材)(discolored wood)와 외부(外部)로 발달(發達)한 정상재색(正常材色)을 구분하는 방어대(防禦帶)(barrier zone)가 형성(形成)되어 있었으며 이 종양상(腫瘍狀) 부위(部位)의 상하(上下)에 위치(位置)한 정상형태(正常形態)의 부위(部位)에서는 정상재색(正常材色)을 나타내는 제(第)2연륜내(年輪內)에 방어대(防禦帶)에 해당하는 위연륜상대(僞年輪狀帶)(false ring-like zones)가 형성(形成)되어 있었는데 이러한 방어대(防禦帶)와 위연륜상대(僞年輪狀帶)는 비정상적(非正常的)으로 과다한 이상형태(異常形態)의 유세포(柔細胞)와 상해(傷害)검구(溝) 및 검강(腔)으로 구성되어 있는 특징(特徵)을 나타내고 있다. 종양상(腫瘍狀) 부위(部位)에 있어서 종양재((腫瘍材)인 제(第)3연륜(年輪)과 방어대(防禦帶)후에 발달(發達)한 제(第)2연륜부분(年輪部分)은 불규칙(不規則)한 연륜계(年輪界), 매우 불규칙적(不規則的)인 구조(構造)를 지니는 이상조직(異常組織), 비정상적(非正常的)인 형태(形態)를 나타내는 목섬유(木纖維) 및 도관요소(導管要素), 비정상적(非正常的)인 형태(形態)를 지니는 방사조직(放射組織)을 가지며 추재부(秋材部)에 고립관공(孤立管孔) 및 복합관공(複台管孔)이 발달(發達)하며 스트랜드유세포(柔細胞)와 방사유세포(放射柔細胞)에 결정(結晶)이 존재(存在)한다는 면에서 서로 유사(類似)하였다. 그리고 제(第)3연륜(年輪)인 종양재(腫瘍材)의 춘재부(春材部) 관공(管孔)의 수(數)는 정상재(正常材)보다 작은 것으로 나타났다.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.327-334
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• 2017

The flood pulse in streams enhances the biodiversity and ecosystem services of the channel-floodplain ecosystems by exchanging water, nutrients, sediments and organisms. However, the lateral connectivity in most streams of Korea has been disrupted by the levee constructions for the purpose of flood control and land use of floodplains. To compare the characteristics of floodplain vegetation according to existence of lateral connectivity in streams, we investigated the geomorphological and soil environmental factors and structures and distribution of vegetation in the floodplains connected and isolated by levee to the channel in Cheongmi Stream, Seom River, Hwangguji Stream, Mangyeong River, Gomakwon Stream, and Boseong River, Korea. In comparison of soil environments, moisture and clay contents were higher in the isolated floodplain than in the connected floodplain. According to the result of principal component analysis (PCA) using environmental data, the environments of the connected floodplain and the isolated floodplain were separated by soil moisture contents, soil texture and distribution altitude of the vegetation. The results of detrended correspondence analysis (DCA) using vegetation data showed that the isolated floodplain was dominated by the hydropythic communities of diverse life form and that the connected floodplain was dominated by the hygrophytic communities that endure disturbance. In conclusion, it is thought that the vegetation of the floodplain changed to the lentic wetland vegetation dominated by diverse hydrophytes as the floodplain was isolated from the channel by artificial levees.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.103-115
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• 2013

The purpose of this study was to analyze fish fauna and species compositions along with trophic guilds, tolerance indicators, and fish community conditions before weir construction (BWC) and after weir construction (AWC) in the Yeongsan River watershed. Total 45 and 44 fish species were sampled in BWC and AWC, respectively without any distinct differences through weir constructions. Fish fauna analysis revealed that the dominant species was the same, Zacco platypus with 24.3% and 20.8% in BWC and AWC, respectively. However, the subdominant species were Carassius auratus with 8.9% in BWC but Opsarichthys uncirostris amurensis with 20.3%, almost identical that of the dominant species AWC. This phenomenon showed the distinct modification of species composition in the watershed. We sampled the $1^{st}$ class endangered species, Liobagrus obesus in tributary stream as previously reported. Also Culter brevicauda was sampled in the mainstream of Yeongsan River watershed and this was the first sampled record in this watershed. One of the most important features were an increase of exotic species, such as Micropterus salmoides and Lepomis macrochirus, with 3.2% BWC vs. 10.2% AWC as well as the increase in tolerant species with 49.2% BWC vs. 73.7% AWC, indicating ecological degradation through weir construction. Overall, our results indicated that fish fauna and composition analyses showed distinct ecological degradations related to increases of exotic and tolerant species AWC. Further long-term studies of fish monitoring should be conducted in the future to configure existent status of river conditions and to provide key information in order to conserve the healthy ecosystem.

• Korean Journal of Environment and Ecology
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• v.18 no.1
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• pp.92-102
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• 2004

In this study, landscape changes were examined by periods through the analysis of visual quantity on the landscape components of national road including the mountains, the sky, road pavements, street trees, paddy fields and dry fields, billboard, telegraph pole, building, structure, slope, guard fence, soundproof wall, and median strip etc. For this, subject national road in suburb arreas was selected to grasp its landscape characteristics, and divisional criteria of landscape type of the national road were suggested to look into the trend of landscape changes by periods. Findings of this study are as follows：1.Divisional criteria of landscape type of the national road include location and geometry, structure, land use, perspective, and surrounding buildings of the national road. 2.The highest visual quantity was found in road pavements by periods among landscape components of the national road. It was found that this result has a thread of connection with previous study emphasizing the importance of road geometry as one of landscape components, and road geometry shall be regarded as a visually significant component in analyzing and evaluating landscape of the national road. 3.Most distinguished factors of landscape changes of the national road by periods were median strip(F＝33.296) and street tree(F＝32.881), and then the sky(F＝24.735) and mountain(F＝23.477) showed similar level of statistically significant difference. However, statistically significance difference was not found in buildings and structures. 4.It was shown that natural elements decreased gradually but structural landscape made of artificial elements became the main in construction of the national road. This result implies that although the scenic and ecological soundness is recognized in construction of the national road, it is not out of the limitation of functionalities that is, access and mobility.