• Journal of the Korean Geotechnical Society
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• v.25 no.1
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• pp.77-88
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• 2009

Cone factors, $N_{kt}$, $N_{ke}$ and $N_{{\Delta}u}$, for estimating undrained shear strength of Busan clay are evaluated in this study. For this, CPTu and field vane tests are performed for clay layers at two sites, Busan new-port and Noksan, and also $CK_0U$ triaxial tests with undisturbed samples taken from the same site are carried out. From experimental results, it is observed that the undrained shear strengths of clay increases with depth, and the undrained shear strength obtained from triaxial tests is 1.5 times higher than one obtained from vane tests. The normalized undrained shear strengths of Busan clay from triaxial and vane shear tests are $0.26{\sim}0.44$ and $0.20{\sim}0.23$, respectively. In CPTu results, cone tip resistance ($q_c$) and pore pressure ($u_2$) linearly increase with depth, and the pore pressure ratio ($B_q$) of Busan clay is within the range of $0.3{\sim}1.0$. The cone factors, which are determined by comparing the CPTu results with $CK_0U$ triaxial and vane shear test results, are found to be $5{\sim}20$ and $10{\sim}35$, respectively. It is also observed that the cone factors are inversely proportional to the pore pressure ratio. From this, the prediction methods for evaluating the cone factors of Busan clay are developed.

• Journal of the Korean association of regional geographers
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• v.16 no.2
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• pp.100-109
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• 2010

The study examines two different sites to analyze the difference of stream channel profile between two different landuse areas on Neponset River, Boston, MA. Landuse represents the current status of land in terms of human, agricultural or forest, industry and environmental activity types. According to the previous research, forest and urban area are significantly distinguished in chemical characteristic, shape and bed load of the stream. On the chosen sites, I look at the cross-section profile, the slope, velocity, and roughness of the channels. With the data collected at the site I determined the value for the channel bed material using Manning's equation, and compared with the result of HEC-RAS model with the cross-section profile data I measured. In the forest area, water surface elevation and bed material obtained through Manning's equation are very close to HEC-RAS model result. However, in the resident area the Manning's 'n' value calculated much higher than assumption which was considered as cobble whose 'n' value is 0.03-0.06. The difference could be caused by unusual steep elevation on the site and the dam present down further. With the steep elevation upside of dam, there is critical-depth condition occurs. The difference of Manning's 'n' value reflects the difference of depth. HEC-RAS model was run to analyze the difference and the result shows that depth is 0.36 much less than 0.688 what I computed when the Manning's n value is 0.03(cobble) instead of the result of the study (0.13292). Beside, dam is a major source of fragmentation and degradation of stream, and it's possibly inferred upstream water levels are increased and stream velocity is decreased. This study is meaningful for introduction of HEC-RAS in geography field to analyze different sites with channel bed material, and it is going to be used more actively to manage river and river side.

• International Area Studies Review
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• v.13 no.2
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• pp.226-253
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• 2009

The study analyzes the trend of regional economic development disparity in China, sets up research period from 1952 to 2008, and uses the after-modified regional GDP data by the first national economic census in 2004. The results as follow. Firstly, the Coefficient of variation(CV) with after-modified GDP data lower than the pre-modified data. Secondly, generally speaking, after-reform and open period's disparity lower than pre-reform and open period. In particular, the regional development disparity increased slowly after 1990, not rapidly. Third, the new cycle of the inverse-U type is appeared from 2002. Fourth, compared with Herfindhal-Hirschman index(HHI) and Theil Entrophy index(TEI), the lower level regions more affect to reduce the disparity in 1980s, and it also affect to reduce the disparity after 2000. Fifth, the convergence hypothesis test finds that the regional economic development disparity has been converged in 1978-2008. Sixth, the inverse-U type hypothesis not has statistical significance, from 1952 to 2008, but it has statistical significance from 1991 to 2008. This result same as the CV and the convergence test.

• Korean Journal of Environment and Ecology
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• v.14 no.2
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• pp.119-126
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• 2000

충남 사문암 지역인 광천, 홍성, 백동, 대흥 및 유구지역의 토양, 식물체(참억새, 쑥, 리기다소나무) 및 지표수, 갱내수의 중금속 함량을 분석한 결과 사문암 토양의 Ni, Cr 및 Co 원소가 변성암 토양에 비하여 10~13배높았으며 이 원소들이 serpentine factor로 생각된다 사문암 지역간에는 이들원소의 차이가 뚜렷하지 않았다 변성암 토양식물에서보다 사문암 토양 식물에서 Ni, Cr, Co등이 높았다 리기다소나무의 원소 흡수량은 비교적 낮았고 3종 식물에서 대체로 뿌리의 원소 함량이 지상부 함량보다 높았으며 사문암 토양에서는 Ni, Cr, Co, Mo, Sc, As 및 Fe 원소들이 쑥보다 참억새에서 높았다 사문암 토양에서 생육하는 식물체 지상부의 생물학적 흡수계수는 Ni, Cr, Co, Zn, Sc, As 및 Fe 원소는 참억새에 높고Zn은 쑥에서 높았다,. 사문암 토양에서 뿌리로부터 지상부로의 원소 전이는 Ni, Cr, Co, Zn As 및 Fe 원소에 대해 쑥에서 높았고 Mo와 Sc 원소는 리기다소나무에서 높았다. 따라서 사문암 토양에서 참억새가 중금속의 흡수율은 높고 중금속에 대한 내성은 강할 것으로 사료된다 대흥지역에서 광산의 오염이 지표수 및 갱내수의 Ni. Cr, Co, Zn 및 Fe 등의 원소 농도를 높게 하였으며 비오염 계류는 오염계류의 원소 농도를 희석시켰다.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1078-1085
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• 2005

1990년 이래 낙동강 하구 서쪽지역인 서부산과 인근 지역에서는 대단위 지반조성공사가 수행되었다. 이 지역에서는 부산점토라고 명명된 점성토가 20-70m의 두께로 상당히 두텁게 형성되어있다. 최근에 들어 정교한 지반조사가 수행됨에 따라 이 지역의 점토에 대한 공학적 특성이 효과적으로 밝혀졌지만, 점토의 특성을 면밀히 규명하기 위해서는 여전히 많은 과제가 남아있다. 본 논문에서는 부산신항 지역에서 점토에 대하여 다양한 방법으로 투수계수를 구하여 투수특성을 규명하고자 한다. 이를 위하여 수평 및 연직방향의 배수에 의한 일정변형률(CRS) 압밀실험, 표준압밀실험 및 압밀 중에 변수위 투수실험이 실내실험으로 이루어 졌으며, 현장실험으로 CPTU에 의한 소산실험 및 Casagrande형 피에조미터에 의한 소산실험이 실시되었다.이들 결과를 서로 비교하여 합리적인 실험결과를 분석하며, 이점토에 대한 깊이별 투수계수 및 투수 이방성을 규명하고자 하였다.

• The Journal of Engineering Geology
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• v.10 no.1
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• pp.27-38
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• 2000

We hydrogeologically studied a mountainous area and its vulnerability to groundwater contamination. Groundwater flow and recharge occur mainly through a network of fractures in this areaTransmissivity and storativity obtained from slug, slug interference, and pumping tests range from 3.2$\times$10$^{-3}$ to 2.0$\times$10$^{-2}$$m^2$/min and 1.3$\times$10$^{-7}$ to 9.15$\times$10$^{-4}$, respectively. The groundwater was contaminated bylivestock activities in the upgradient. The groundwater in the downgradient residential area wasthreatened by the upgradient livestock activities.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.403-409
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• 2000

In this paper, we measured and analyzed cross polarization discrimination(XPD), signal correlation coefficient($\rho$) and received signal level decrease, for the application of polarization diversity scheme in the up-link of microcell environments. We experimented in a dense building area, a dense residence area, a market area, a school area and etc at 1.9 GHz. Cross polarization discrimination (XPD) is about 6~11 dB, signal correlation coefficient($\rho$) is below 0.7 and received signal level decrease is smaller than 3 dB. The results of comparing polarization diversity with space diversity show that polarization diversity gain is about 2~5 dB higher in the various area. As a results, polarization diversity scheme is more effective than space diversity scheme in microcell environments.

• Journal of the Korean Solar Energy Society
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• v.39 no.3
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• pp.91-102
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• 2019

Decomposition models are essential in TMY development and solar energy system design. Up until recently, only a few decomposition model related researches are implemented in Korea due to lack of measured direct normal solar irradiance. In contrast, numerous researches have been conducted in various countries, and some quasi-universal composition models have been recommended by several papers. In this research, three decomposition models - Watanabe model, Reindl-2 model and Engerer1 model - are selected and their site-fitted coefficients are developed using measured direct normal solar irradiance in Seoul. R-squared, RMSE, MBE of the site-fitted models are compared with the case of original coefficients and then each other. The comparison result shows that the Reindl-2 model with site-fitted coefficients is best suitable for Seoul. Further researches will be conducted to find the best model using more various measured data of Korean cities and site-fitting methods.

• Journal of Korean Society of Forest Science
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• v.68 no.1
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• pp.46-51
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• 1985

This study was carried out to know the variation of some leaf characteristics in Phyllostachys bambusoides by district and stands in Korea. The results obtained were summarized as follows ; The coefficients of variation of leaf characteristics in Iri were higher than the other districts. The variation coefficients of leaf characteristics were highly shown among stands in districts. The leaf characteristics were not significant differences in districts except in Iri. The leaf characteristics among stands were significant differences. The frequency distributions of form quotient of leaf blade width/leaf blade length were shown to be different from Gyeongju and Ulsan districts. In conclusion, the variations of leaf characteristics of Phyllostachys bambusoides were highly showed among stands in districs.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.330-339
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• 2017

In Korea, metropolitan cities and provinces are responsible for setting up their own Regional Forest Plans to manage the forests at regional scales distinguished by administrative boundaries, and the role of the plans are very crucial by linking the Forest Basic Plan for nationwide forest management policy with Forest Management Plans for local-level forest management practices. Thus, the analysis of forest resources at regional levels is required to make more efficient regional forest plans by properly reflecting regional forest situations. This study aims to present which species are concentrated at each individual metropolitan city or province, contributing to more efficiently establishing its regional forest plan. In order to measure the concentration levels of species for each region, Location Quotient and Relative-Specialization Index are computed using area- and volume-data for the major species selected in the Statistical Yearbook of Forestry. As a result, the ranks among the indices of the major species for each individual municipal city and province are presented. The results from this study can contribute to the selection of regional target species and establishment of regional forest management objectives. Further study regarding the differences between the results from area-based and volume-based indices will be helpful to consider regional level productivity by species into the regional forest plans.