• 한국측량학회지
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• 제31권6_1호
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• pp.431-437
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• 2013

산사태는 지진이나 집중 호우로 인해 발생되며, 최근 산사태의 발생이 증가하고 있다. 하지만 정확한 산사태의 발생을 예측하는 것은 불가능하다. 이에 본 연구에서는 공간 분석 기법과 AHP 방법을 사용하여 산사태 관리 시스템의 요소를 세분화하고자 한다. 기존의 산사태 관리 시스템은 경사 방향 요소에 대한 가중치 없이 기울기의 요소로 구성되어 있다. 산사태 발생 위험 예측의 정확도 향상을 위해서는 경사 방향에 대한 가중치를 고려하여야한다. 본 연구에서는 경사 방향을 세 가지 범주에서 분류하였다. 경사방향이 산사태에 영향을 주지 않는 경우는 고려하지 않았다. 이러한 결과를 바탕으로 산사태 관리 시스템의 개선방향을 제시하고자 한다. 분석 결과, 경사 및 경사 방향에 분할이 필요하며, 지형 요소에 대한 분류로 산사태 관리 시스템의 정확도를 높일 수 있다고 판단된다. 본 연구에서는 지형요소만을 고려하였지만, 향후 연구에서는 다른 인자들을 고려한 세분화가 필요하다고 생각된다.

• 산업기술연구
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• 제22권A호
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• pp.153-159
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• 2002

This paper is an experimental work of estimating friction angle of very coarse grained soil such as rubble mound by performing laboratory experiments. Two crushed rocks of rubble mound were used for tests. Triaxial compression tests with drained conditions were performed to measure friction angles of soils prepared by mixing the crushed soil having an identical coefficient of uniformity with different maximum grain size distribution. Centrifuge model experiments with those soils were also performed to measure angle of repose and to estimate friction angle of soil from measuring the slope of slip line in the active stress state. Model tests were carried out by changing the G-levels of 1G and 50G. From triaxial compression tests, the measured value of friction angle of soil is in the range of $41{\sim}57^{\circ}$. The measured value of repose angle is in the range of $32{\sim}35^{\circ}$. The values of friction angle are found not so sensitive to the maximum grain size of soil as long as the coefficient of uniformity is identical. Estimated value of friction angle from measuring the slope of slip line in the active stress state is in the range of $30{\sim}46^{\circ}$. Thus, the estimated angle of friction are found to be greater in the order of the measured angle of repose, the estimated value from the slope of active state, and triaxial compression test results. On the other hand, the measured values of friction angle from triaxial tests were compared with empirical equations, based on the relation between friction angle and void ratio. Equations proposed by Helenelund(l966) and Hansen(1967) found to be relatively reliable to estimate friction angles of soil.

• 대한물리의학회지
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• 제11권3호
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• pp.49-54
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• 2016

PURPOSE: This study was implemented to measure the muscle activity of muscles surrounding shoulder during push-up exercise according to the slope angle. METHODS: This study has research subject consisting of 25 normal male adults without neurologic or musculoskeletal injury in shoulder part. EMG was used as a tool for measuring muscle activity and four muscles including upper trapezius (UT), middle trapezius (MT), Lower Trapezius (LT), and Serratus Anterior (SA) were chosen for measuring the muscle activity of muscles surrounding shoulder. Tilting table slope was set at $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$ and push-up motion was performed three time for each case to use the average value. The measured value was used after generalization process to create %RVC value where the measured value was standardized by using $0^{\circ}$ as a standard. RESULTS: There was a difference of muscle activity according to the tilting table slope during push-up exercise. In UT, MT, and SA, there was no significant $0^{\circ}$ and $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$. But there was significant $30^{\circ}$ and $45^{\circ}$. LT was significant difference between $45^{\circ}$ and $60^{\circ}$ (p<.05). CONCLUSION: There are cases where push-up exercise should be selectively implemented due to shoulder problems. According to this results between $0^{\circ}$ and $30^{\circ}$, push up will be able to more effectively exercise. Applying proper angle of tilting table for push-up to patients who have difficulties in performing motions along with physical consumption can deliver effective and easy exercise program.

• 한국환경농학회지
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• 제24권4호
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• pp.334-340
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• 2005

This experiment was conducted to evaluate the nutrient loss and to assess the eutrophication into small stream by intensive rains in the steeped cornfield during cultivation. The crop cultivated was a soiling com (DW5969), and the experimental plots were divided into two parts that were 10 and 18% of slope degrees. The amount of T-N and T-P loss was calculated by analysis of surface run-off water quality, and was investigated the effect of eutrophication to small stream as a part of life cycle assessment (LCA) methodology application. For the surface run-off water quality, EC and T-N values were highest in first runoff event as compared to the other events and maintained the stage state with litter variations at every hour during the runoff period except for EC in the slope 18%. However, T-P concentration has been a transient stage after runoff event of July 27. Total surface run-off ratio was not significantly different with slope degrees, but amount of T-N and T-P losses at 18% of slope were high as $5.96kg\;ha^{-1}\;and\;0.65kg\;ha^{-1}$ as relative to 10% of slope degree, respectively. Furthermore, T-N losses from run-off water in the sloped cornfield 10 and 18% were approximately 9.8 and 12.5% of the N applied as fertilizer when the fertilizer applied at recommended rates after soil test, respectively. For the eutrophication impact to the small stream, it was shown that $PO_4$ equivalence and Eco-indicator value at 18% of slope degree were greater as much $6.11kg\;ha^{-1}$ and 0.81 as compared to the slope angle 10%, respectively. Therefore, it was appeared that each effect of nutrient losses, eutrophication and Eco-indicator value was enhanced according with higher slope degree.

• 지질공학
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• 제29권2호
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• pp.123-136
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• 2019

본 연구는 비탈면의 불안정으로 인한 붕괴현상인 땅밀림 붕괴가 발생하는 지역에 지하수위 하강을 위한 집수정의 설치 효과를 평가하기 위해서 수행되었다. 비탈면은 지형, 지질적인 내적 특성과 강우와 지진 등 외적 요인의 불안정성이 증가하는 경우 붕괴현상이 유발된다. 우리나라는 우기의 강우 침투에 의하여 토층 내 지하수위가 증가하고, 이로 인한 간극수압의 형성 및 하중 증가로 인하여 붕괴현상이 발생된다. 토양 내 강우침투로 인한 비탈면의 붕괴로 산림훼손이 급증하고 있는 현실이다. 연구대상 비탈면은 계곡과 인접하여 위치하고 지형 형태상으로는 완경사지의 산록완경사면에 해당하고, 붕괴면 상부는 급경사지를 이루고 있다. 땅밀림이 발생되는 지형에 보강공사와 더불어 비탈면에 집수정 설치로 인한 지하수위 변화를 계측하였다. 계측자료를 통하여 집수정이 비탈면에 미치는 연관성을 분석하고자 집수정 설치 전 후의 지하수위-강우량 비를 산출하였으며, 분석 결과 집수정 설치로 지하수위-강우량 비가 증가하여 지하수위를 저하시키는 영향이 있음을 확인하였다. 선행강우량을 3일, 7일, 15일 기준으로 강우량에 따른 지하수위 변화를 분석한 결과, 전체적으로 지하수위가 높으면 지하수위-강우량 비 $r_p$가 작게 나타났으며 지하수위가 낮아지면 상대적으로 큰 값을 보였다. 또한 본 연구지역과 같이 집수유역이 큰 비탈면의 경우는 선행강우량이 지하수에 미치는 영향이 3일 < 7일 < 15일 선행강우량 순으로 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1306-1310
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• 2009

The roughness coefficients were estimated by the Manning's equation for the measured stage and flow velocity of Bocheong stream basin in Kum river. The relationships between the estimated roughness coefficients and the geomorphologic factors were formulated by the linear, logarithmic, exponential and power type function, thereafter correlation equations were presented. The correlation analysis was performed between the measured stream length and the basin area of Bocheong stream basin by the linear, logarithmic, exponential and power type function, and correlation equation for the stream length was given. The roughness coefficient has strong correlationship with stream slope, but low correlation coefficients with stream length and basin area. For the correlationship with the roughness coefficients and the stream slope, the logarithmic type function has the smallest correlation coefficient, on the other hand, the exponential type function has the largest correlation coefficient. For the relationship between the stream length and the basin area, the correlation coefficient of the logarithmic type function shows the smallest value, linear type function shows the largest value.

• 한국측량학회지
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• 제10권2호
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• pp.57-62
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• 1992

산지가 많은 우리나라에서는 인구가 증가함에 따라 토지의 이용이 평지에서 경사지로 이동되고 있으며, 산사태와 같은 자연재해는 인명의 손실, 재산상의 손실, 그리고 자연환경 파괴를 일으켜 그 연구의 중요성이 증가하고 있다. 산사태 예측에 있어서 단일사면에 대한 안정검토해석이 아닌 광범위한 지역의 위험지 예측은 중요한 과제라 할 수 있다. 본 연구에서는 산사태 지역의 항공사진 스캐닝으로 얻은 이미지밝기값의 평균 및 표준편차에 대한 상관관계를 알 수 있었다. 산사태 지역에서는 밝기값 범위가 35~65에 분포하였고, 표준편차가 경년변화에서 조금씩 증가하는 것으로 나타났다. 또한, 넓은 지역의 산사태 조사에서는 항공사진 자료에 의해 경사도, 토질특성, 피복상태의 상관관계를 구할 수 있다.

• Geomechanics and Engineering
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• 제23권1호
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• pp.15-30
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• 2020

The probabilistic bearing capacity of a strip footing placed on the edge of a purely cohesive reinforced soil slope is computed by combining lower bound finite element limit analysis technique with random field method and Monte Carlo simulation technique. To simulate actual field condition, anisotropic random field model of undrained soil shear strength is generated by using the Cholesky-Decomposition method. With the inclusion of a single layer of reinforcement, dimensionless bearing capacity factor, N always increases in both deterministic and probabilistic analysis. As the coefficient of variation of the undrained soil shear strength increases, the mean N value in both unreinforced and reinforced slopes reduces for particular values of correlation length in horizontal and vertical directions. For smaller correlation lengths, the mean N value of unreinforced and reinforced slopes is always lower than the deterministic solutions. However, with the increment in the correlation lengths, this difference reduces and at a higher correlation length, both the deterministic and probabilistic mean values become almost equal. Providing reinforcement under footing subjected to eccentric load is found to be an efficient solution. However, both the deterministic and probabilistic bearing capacity for unreinforced and reinforced slopes reduces with the consideration of loading eccentricity.

• 한국환경복원기술학회지
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• 제6권4호
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• pp.24-32
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• 2003

This study was carried out to select proper species for early stage replantation of forest road cut-slope. From one to fourteen year elapsed forest roads in Gangwon-do, sample plots were selected, and their vegetations and environmental factors were investigated. Invaded species with high frequency ordered Lespedeza cyrtobotrya, Lysimachia clethroides, Rubus crataegifolius, Patrinia villosa, Spodiopogon sibiricus, Pueraria thunbergiana, Youngia denticulata, Dactylis glomerata, Rhus chinensis, and Pinus densiflora. North cut-slope have the highest value of invaded species number and plant coverage, and so, north aspect could be best for plant invasion. According to ordination, distribution of species were influenced by elapsed year, cut-slope aspect, and cut-slope. Lespedeza bicolor, Lespedeza cyrtobotrya, Artemisia stolonifera, Miscanthus sinensis, Rubus crataegifolius, Rhus chinensis, Lindera obtusiloba, and Pinus densiflora were considered with proper species for replantation at south slope. Also, Lespedeza bicolor, Lespedeza cyrtobotrya, Arundinella hirta, Artemisia keiskeana, Astilbe chinensis var. davidii, Rubus crataegifolius, Weigela subsessilis, Stephanandra incisa, and Rhododendron mucronulatum were considered with proper species as replantation at north slope.

• Journal of Korean Neurosurgical Society
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• 제56권6호
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• pp.455-462
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• 2014

Objective : To propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study. Methods : The proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included. Results : We found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery. Conclusion : Our results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring.