• Journal of Korean Society of Transportation
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• v.32 no.2
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• pp.170-178
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• 2014

Until now, several research on the relationship of traffic crash occurrences and geometric had been conducted and revealed that projects of road alignment, geometric improvement and hazardous segment selection reduced the number of accidents and accident severities. However, such variables did not consider the non-homogeneous characteristics of roadway segments due to the difficulty of data collection, which results in under-estimation of the standard error affecting the overall modeling goodness-of-fit. This study highlights the importance of non-homogeneity by looking at the effect of the non-homogeneous geometric variables through the modeling process. The model delivers meaningful results when using some geometric variables without relevant geometrics' variables.

• Current Research on Agriculture and Life Sciences
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• v.25
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• pp.13-18
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• 2007

The aim of this research is to set improvement guidance a character analysis of woodland edge to cope with the ecological dysfunction of woodland which was caused by massive development project and thoughtless development in country areas. The summary of research result are as follows. 1) From the result of landscape ecology characteristic analysis of woodland in all seven research sites, to begin with, in proportion of appearance by vegetation layer and condition of composition, site 5 showed to be most satisfactory. 2) A width of woodland edge was revealed 7.5m as a minimum, 17.0m as a maximum, and 11.4m as a average and minimum edge was set as 10m according to integrated analysis on each example place. 3) As a result of flexibility analysis, site 1, 2 and 5 was shown high value 3, and it is thought that curve rather than linearity should be maintained in order to increase the ecological function. Also, a phenomenon of straight was prominent, and as a woodland edge, green network and buffering system showed to be somewhat unsatisfactory. 4) Based on the result of character analysis of landscape ecology, main guidelines for improvement of woodland edge were categorized into five in parallel structure and three in vertical structure respectively. The guidelines for improvement of woodland edge suggested by the research has a deep meaning in that it is used as a basic material to induce for controling more systematically or landscape-friendly the defamed forest problems caused by road construction, various development projects, and enlargement of agricultural lands.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.108-117
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• 2009

The South Korean government is looking for a solution to the ever-growing problems of traffic congestion, and surging international oil prices: the use of the humble bicycle to get to places. However, Many people feel inconvenient using bicycle because of the insufficient bicycle infrastructure and lack of the safety and connectivity between existing pathways. In this study, bicycle level of service model using ordered probit model is developed considering safety, convenience, connectivity, and factors that affect bicycle LOS. The ordered probit model would be recommended for the research which relates in choice, preference and strength etc. Bicycle level of service criteria is calculated by applying this model reflecting bicyclist's point of view. The model which develops from this research which accomplishes a bicycle level of service evaluation and represent alternative solution to encourage bicyclist. It is believed that the proposed model would be greatly utilized in bicycle network planning, bicycle road and facility alternatives testing, projects funding priority.

• Current Optics and Photonics
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• v.1 no.3
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• pp.207-213
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• 2017

The Adaptive Front-lighting System (AFS) is a part of the active safety system, providing optimized vision to the driver during night time and other poor-sight conditions of the road by automatic adaptation of lighting to environmental and traffic conditions. Basically, an AFS provides four different modes of the passing beam as designated in an United Nations Economic Commission for Europe regulation (ECE324-R123): neutral state or country light (Class C), urban light (Class V), highway light (Class E), and adverse weather light (Class W). In this paper, we first present an optics design for an AFS system capable of producing the Class C/V/E/W patterns requiring only on/off modulation of multi-array LEDs with no need for any additional mechanical components. The AFS optics consists of two separated modules, cutoff and spread; the cutoff module lights a narrow central area with high luminous intensity, satisfying the cutoff regulation, and the spread module forms a wide spread beam of low luminous intensity. Each module consists of two major parts; the first converts a discretely positioned LED array into a full-filled area emitting light source plane, and the second projects the light source plane to a 25 m away target plane. With the combination of these two optics modules, the four beam patterns are formed by simple on/off modulation of multi-array LEDs. Then we report the development of a prototype that was demonstrated to provide the four beam patterns.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.5
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• pp.1-16
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• 2018

The purpose of this study is to identify the fragmented points of mountain ranges in Daegu metropolitan city using New Sangyeongpyo (Chart of Mountain Ranges), road system map and GIS spatial analysis, and to prioritize the identified fragmented points for restoration based on quantitative assessment. Moreover, this study proposes restoration plans reflecting the assessment results and characteristics of each fragmented point. The results of this study are summarized as follows: First of all, analysis of the distribution of mountain ranges in Daegu metropolitan city showed that jimaek and semaek in Daegu account for 2% of all mountain ranges in the country, implying that the mountain ranges of Daegu do not hold significant ranking on a national level. However, it was found that numerous fragmented points are appearing due to roads. According to the analysis, 35 fragmented points were identified, of which 15 were found to be restorable. In terms of restoration potential and involved risks, assessment results of the 15 fragmented points indicated that 6 points are at Grade I, 3 points are at Grade II and 6 points are at Grade III. Therefore, a methodology of restoring fragmented mountain ranges was proposed through three suggestions of restoration plans that consider the characteristics of each fragmented points. The results of this study are expected to be highly useful as basic data for effective restoration of mountain ranges in connection with mountain range restorations and relevant projects implemented on a national level in the future.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.141-148
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• 2017

Over the past 30 years, the business effects of the improvement project at black spot have been decreasing since 2010, with a reduction in the amount of government spending, coupled with proposing a uniform improvement plan. In order to promote more efficient improvement projects, it is necessary to evaluate the efficiency of local governments and improve the business methods of local governments with low efficiency. However, more sophisticated efficiency analysis methods are needed. Because in previous studies have been limited to the analysis of effects before and after the project through the simple before-after analysis. For this purpose, this study analyzed the efficiency of improvement project at black spot by local governments in Gyeonggi-do using DEA to compare and analyze efficiency in various fields. As a result, Goyang, Seongnam, Paju, Hanam and Yangju showed high efficiency local governments. For local governmetns with low efficiency, the improvement projets to improve efficiency were divided into civil engineering work, structure work, pavement work, additional work and transportation work, and the appropriate construction ratios of each local government were analyzed and presented.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.92-99
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• 2016

This study developed a verification and certification method of technologies of green infrastructure (GI) and low impact development (LID) that gained interest recently. The outdoor testbed used in this study consisted of a building type, a road type, a parking lot type, a rain garden type and a bioretention type. Indoor test facilities were ready for testing using hydrology efficient analysis, pavement and soil analysis and water environment analysis. The development of outdoor and indoor test facilities were used to certify the efficiency of GI & LID technologies, and this was expected to contribute to the activation of the related projects by providing reliable data for the application of GI & LID techniques.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.2
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• pp.21-39
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• 1992

Many problems were found out the remarkable unbalance between paddy fields and up-land areas, or between plain and mountainous areas, unreasonable establishing of land consolidaton boundaries without consideration of rural development, lower leverl of construction technology of the roads and canals for agricultral use ad operation and maintenance of them by human power far apart from the ages of high technology, high information and free internationalisation, and too slow progress to overcome the weak agricultural circumstances etc. through the survey in the past executed land consolidation projects. The basic ways for solution of these problems for propulsion of land consolidation project through investigation are summarized as follows : 1. Land consolidation project should be executed to the direction of balanced regional development, laying stress on the upland and mountainous areas in order to carry out the agriculture effectively. 2. the acreage of land consolidation project to be conducted anually should be increased to overcome the serious underdeveloped agricultural development. 3. It should be developed to the way in accordance with the order of land use from the view point of rural integral development including the rural readjustment. 4. The level of the structures of road and canal, the size of standard lot and the grouping of land substitution should be to incraese the productivity of land and labour more than ever and reached to a degree in cope with the age of industrialization, information and free internationalisation. 5. The level of the management of agricultural water use and the maintenace of the various facilities should be developed to be automatization, remote control, central control and information processing instead human work. 6. Land substitution should take a measure of grouping method in accordance with the agricultural plan and farming organization, which can overcome high industrialized society in place of the substition by origin land. 7. Land consolidation project should be planned in order to fulfil a conservative function of ecosystem and resources together with improvement of land and labour productivity.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.67-77
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• 2007

This study deals with the traffic accidents at the unsignalized intersections in Cheongju. The purpose is to analyze the characters and the relations between road environmental factors and traffic accidents. The correlation analyses among the above factors show that the accidents are strongly related to traffic volumes and sight distances in 3-legged, and the cross angles, maximum vertical grades and sight distances in 4-legged unsignalized intersections. Also the multiple linear and nonlinear regression analyses represent that the accidents in the 3-legged increase as the traffic volume and the number of double stop-lines increase, and that the accidents in the 4-legged increase as the cross angle approaches to the 90 degree and decrease as the maximum vertical grade increases. It could be expected that this results give the good implications to the future intersection improvement projects in Cheongju.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.117-127
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• 2009

This study analyzed the uncertainty of the forecasted link traffic flow, and estimated of the interval link flow using Korea Transport Data Base (KTDB) to consider those risks into the feasibility study. In the paper, the uncertainty was analyzed according to the stochastic variation of the KTDB origin-destination traffic. It was found that the uncertainty of the entire network traffic forecasts was 15.4% in average,. when the stochastic variation of the KTDB was considered. The results showed that the more congested the roads were, the bigger the uncertainty of forecasted link traffic flow were found. In particular, we estimated the variance of the forecasted traffic flow, and suggested interval estimates of the forecasted traffic flow instead of point estimates which were presented in the common feasibility studies. These results are expected to contribute the quantitative evaluation of uncertain road investment projects and to provide valuable information to the decision makers for the transport investment.