• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.413-417
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• 2007

노면배수 시설의 설계를 위하여 부등류 해석을 기반으로 한 설계모형을 수립하고 등류 해석을 기반으로 한 설계결과와 비교하였다. 노면배수시설을 설계하기 위해서는 지속시간을 가정하여 설계강우를 결정하고 설계변수인 유출구 간격을 가정하여, 호우에 응답하여 발생하는 홍수의 도달시간이 가정된 지속시간과 유사할 때까지 계산을 반복하여 유출구 간격을 결정한다. 부등류 해석에 의한 수로 흐름 해석은 수로 양단에 유출구를 갖는 수로의 분수계의 위치를 결정하는 과정과 발생하는 최대수심이 허용수심을 초과하지 않도록 수로길이를 산정하는 과정을 포함하므로 등류 해석에 비해 계산과정이 복잡하게 된다. 가상의 노면배수 체계를 설정하고 다양한 수로경사에 대해 노면배수 설계모형을 적용한 결과, 등류해석의 경우 유출구 간격은 수로경사가 증가할수록 증가하였지만, 부등류 해석의 경우 수로경사가 증가할수록 감소하였다가 다시 증가하는 경향을 보였다. 수로경사가 작은 경우 등류 해석보다 부등류 해석을 기반으로 노면배수 시설을 설계하는 것이 합리적인 것으로 판단되었다.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.133-138
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• 2011

This study aims to compare hydraulic & hydrologic design characteristics by examining generated on weak points for road drainage poor sites. More appropriated methodology of rainfall-intensity calculated is to consider minutely rainfall-intensity decision method for road drainage basins. To use non-uniform flow analysis methodology for road surface drainage facilities inlet spacing decision methods is better than present experience inlet spacing decision equations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.841-847
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• 2014

Urban runoff models have been continuously developing with concerns for urban flood. Recently, models that be able to quantitatively analyze surface inundation caused by overflowed water from storm sewer were also developed by coupling 1-dimensional sewer model and 2-dimensional surface flow model. However, only overflowed water from storm sewer can be analyzed by the models have been developed until now. They are limited to be not able to analyze surface inundation caused by surface runoff that could not flow into the storm sewer. In order to overcome the limitation, basin-overlap method was devised adding a dummy 1-dimensional sewer layer to the model, so it can consider the efficiency of inflow to the storm sewer system. XP-SWMM 2011 is applied for urban runoff model and the flood event occurred on July 27, 2011 in basin-shaped Sadangcheon watershed is chosen for study inundation event. According to simulation results basin-overlap method reappear the observed inundation event more precisely than traditional method. This results suggest that drainage system has to be improved for reducing inundation caused by surface runoff and would be used as considerations for planning an urban basin design magnitude.

• Journal of Korea Water Resources Association
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• v.41 no.12
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• pp.1173-1185
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• 2008

The design methods of the road surface drainage facilities were compared for the improvement of design method. We have developed four computational design models classified by the methods to determine the duration of design rainfall and to analyze the flow of a linear drainage channel. The critical duration was determined by assuming the critical duration to be 10 minutes or by finding the duration of design storm being similar to the travel time of flow by trial and error. The flow of a linear drainage channel was analyzed as the uniform flow or the varied flow. The design models were applied to the artificial road surface drainage facilities with various channel slopes and road shoulder slopes. If the rainfall intensity of the 10 minutes duration was applied, the outlet spacing obtained from the design based on the varied flow analysis was larger than the uniform flow analysis only when the channel slope and the road shoulder slope was small. On the other hands, if the duration of design rainfall was determined by calculating the travel time, the varied flow analysis brought about larger outlet spacing than the uniform analysis for all conditions. However, the model of the critical duration concept and the varied flow analysis resulted in smaller outlet spacing than the current design method employing the rainfall of 10 minutes duration and the uniform flow analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.242-242
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• 2020

도시화와 산업화에 따른 유출환경의 변화로 인해 도심지에서 발생하는 대부분의 유출은 도로표면을 따라 이동하고 도로변에 설치된 빗물받이에 의해 배수된다. 이 때 빗물이 원활하게 배수되지 않아 노면수가 정체되고, 이 노면수가 인근 주택지로 유입되어 침수 피해가 발생한다. 이러한 현상은 유출량이 집중되는 도심지 저지대에서 주로 발생하며 설계 한도를 초과하지 않는 정상적인 강우 조건에서도 빈번히 나타나고 있다. 이는 최근의 기후 변화로 인한 집중 호우 등을 고려하여 설계 기준이 지속적으로 조정되어야 함과 동시에 도로 노면수의 배수 능력 평가를 위한 실제적인 연구가 이루어져야 한다는 필요성을 나타내고 있다. 특히 도로 빗물받이의 효율은 주로 종경사 및 횡경사 등의 도로 조건, 표면 유출 우수량, 빗물받이의 형상 등에 의존한다. 그러므로 상향된 설계빈도 및 도로 조건을 고려한 도로 표면 유출에 대한 흐름 분석과 빗물받이 특성을 고려한 실증연구의 분석 및 설계 해석 알고리즘의 개발이 시급한 실정이다. 본 연구에서는 도로 노면수의 배수 능력 증대를 위해 연속 설치된 빗물받이 조건 및 도로 경사조건을 고려하여 도로 배수시설의 표면 유출 모델 설계 알고리즘을 개발하였다. 표면 유출 유량은 도로의 차선(2~4차선), 경사(종경사 2~10% 및 횡경사 2~10%) 및 설계빈도(최대 30년)를 고려하였으며 유량이 노면 진행방향을 따라 연속적으로 증가하는 부등류 흐름 해석 방법을 채택하였다. 또한, 빗물받이 설치간격(L)과 도로의 폭(W)의 곱으로 계산되는 단순 직사각형 형태의 노면 형상이 아닌 도로 종경사 및 횡경사에 따른 유달거리를 산정하여 평행사변형 형태의 노면 형상을 계산하고 이에 따른 면적(A), 도달시간(tc) 및 강우강도(I)를 산정하였다. 이와 같은 1차원 흐름분석을 통해 도로 표면흐름 및 빗물받이 설치 간격을 제시하고 기존의 제시된 빗물받이 설치 간격과 비교하여 본 연구에서 제시한 설계 알고리즘을 검증하였다. 또한, 수리 실험을 통해 측정된 빗물받이 차집효율을 이용하여 연속 구간에서의 도로 표면 유출 모델의 적용성을 제시하였다. 이는 빗물받이 유입구를 통해 모든 유량이 유출된다고 가정하고 단독 구간에서의 수리분석 결과만을 고려하여 이를 확장시켜 개발된 기존의 도로 표면 유출 모델을 보완할 수 있을 것으로 기대된다. 본 연구에서 제시하고 있는 설계 알고리즘을 적용한다면 도로 전체 구간에서의 흐름 변화 분석과 배수효율의 정량적인 분석이 가능하므로 향후 도로 표면 침수 피해 저감 및 배수능력 증대를 위한 실증적이고 정량적인 분석 방법이 될 것으로 판단된다.

• Journal of the Korean association of regional geographers
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• v.17 no.4
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• pp.416-431
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• 2011

Hiking trails in Mt Jiri, and Mt Halla, National Park have been examined in terms of their degrading factors. The trails are deteriorated by natural erosion processes as well as human trampling. Trail deterioration is classified into tread lowering, sidewall retreat, path widening and divergence based upon a place where erosional processes occur. Tread lowering and sidewall retreat is generally produced by natural erosion factors, whereas path widening and divergence is generated by human trampling. Rainwash is the most contributing process to tread lowering. By contrast, several processes such as rainwash, needle ice action, deflation, tree falling and animal activity play a major role in sidewall retreat according to physical conditions of a hiking trail. Path widening and divergence could be classified by a factor producing human trampling. There are lots of cases related to rainwash such as the tree root, gravel, and bedrock, exposed by a surface flow lowering a tread and the riser produced by tread scouring. A puddle of rainwater on a flat tread and a fallen tree of Abies koreana in a forest region are also major factors to cause path widening and divergence. A paved tread with stones encourages a hiker to walk out of a trail. Taking a shortcut also results in path widening and divergence without a factor giving a hiker inconvenience on a trail.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.43-51
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• 2009

This paper investigates the accuracy of vehicle pre-braking speed estimates based upon tire/roadway coefficient of friction (drag factor) measurements and skid mark measurements Data for pre-braking and pre-skidding speeds were collected to determine if there were any correlations between pre-braking speeds and pre-skidding speeds. Braking tests were performed on two vehicles using various measurement devices including a fifth wheel, a speed gun, and a vericom 2000. The vehicle speeds, braking distances, skid mark distances, and deceleration histories were recorded. From these data. coefficients of friction and vehicle pre-skidding speeds for the tested road surface were calculated. The pre-skidding speeds were then compared to the actual pre-braking speeds of the vehicles in order to establish relationships between pre-skidding and pre-braking speed. A correlation between the Pre-skidding speed and the actual pre-braking speed was established for the study data.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.4
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• pp.71-79
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• 2019

By using convolutional neural networks (CNNs) based on semantic segmentation, road surface damage detection has being studied. In order to generate the CNN model, it is essential to collect the input and the corresponding labeled images. Unfortunately, such collecting pairs of the dataset requires a great deal of time and costs. In this paper, we proposed a road surface damage detection technique based on semi-supervised learning using pseudo labels to mitigate such problem. The model is updated by properly mixing labeled and unlabeled datasets, and compares the performance against existing model using only labeled dataset. As a subjective result, it was confirmed that the recall was slightly degraded, but the precision was considerably improved. In addition, the $F_1-score$ was also evaluated as a high value.

• Journal of Korean Society of Transportation
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• v.33 no.3
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• pp.284-293
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• 2015

The objective of this paper is to determine the conditions of road surface by utilizing the images collected from closed-circuit television (CCTV) cameras installed on roadside. First, a technique was examined to detect wet surfaces at nighttime. From the literature reviews, it was revealed that image processing using polarization is one of the preferred options. However, it is hard to use the polarization characteristics of road surface images at nighttime because of irregular or no light situations. In this study, we proposes a new discriminant for detecting wet and dry road surfaces using CCTV image data at night. To detect the road surface conditions with night vision, we applied the wavelet packet transform for analyzing road surface textures. Additionally, to apply the luminance feature of night CCTV images, we set the intensity histogram based on HSI(Hue Saturation Intensity) color model. With a set of 200 images taken from the field, we constructed a detection criteria hyperplane with SVM (Support Vector Machine). We conducted field tests to verify the detection ability of the wet road surfaces and obtained reliable results. The outcome of this study is also expected to be used for monitoring road surfaces to improve safety.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.699-700
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• 2008