• The Journal of Engineering Geology
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• v.17 no.2 s.52
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• pp.163-176
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• 2007

Landslides which is one of the major natural hazard is defined as a mass movement of weathered material rock and debris due to gravity and can be triggered by complex mechanism. It causes enormous property damages and losses of human lift directly and indirectly. In order to mitigate landslide risk effectively, a new method is required to develope for better understanding of landslide risk based on the damaged cost produce, investment priority data, etc. In this study, we suggest a new evaluation method for slope stability using risk analysis. 30 slopes including 10 stable slopes, 10 slopes of possible failure and 10 failed slopes along the national and local roads are examined. Risk analysis comprises the hazard analysis and the consequence analysis. Risk scores evaluated by risk analysis show very clear boundaries for each category and are the highest for the failed slopes and the lowest for the stable slopes. The evaluation method for slope stability suggested by this research may define the condition and stability of slope more clearly than other methods suggested by others.

• Journal of the Korean GEO-environmental Society
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• v.21 no.3
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• pp.5-11
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• 2020

Recently, ground pits that have been occurring frequently in urban areas are hindering traffic flow and causing property damages and loss of human life, acting as factors that are threatening the safety of citizens. Therefore, sunken ground must be quickly restored and provisions must be made for additional damage but current domestic detailed standards regarding ground pits and accurate definitions regarding causes and measures to be taken for reoccurrences are lacking. Restoration methods of sunken ground include backfilling by reusing sunken soil or other fill material and paving the road and while this is the most often used method, this only prevents ground from sinking temporarily and can not serve as a fundamental solution. Also, additional ground pits can occur on ground that is reinforced using this method due to faulty backfill material or faulty hardening. This study used Eco-friendly High-Strength Material (EHSM) as restoration material that can be used in the restoration of underground cavities that have occurred due to ground subsidence to analyze the engineered characteristics of modified dredging clay and test pieces made from changed ratios of EHSM and weathered granite soil were uniaxial compression tests were conducted and freezing-thawing tests were conducted to study strength properties according to environmental changes of restoration material, and after tests were concluded by each level, uniaxial compression tests and dynamic elasticity tests were conducted for intensity analysis. Also, to evaluate strength characteristics of the restored ground, dynamic plate load tests were conducted to verify the improvement effectiveness of the restored ground.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.639-645
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• 2018

This paper is intended to develop a decision model that can be applied to autonomous vehicles and autonomous mobile vehicles. The developed module has an independent configuration for application in various driving environments and is based on a platform for organically operating them. Each module is studied for decision making on lane changes and for securing safety through reinforcement learning using a deep learning technique. The autonomous mobile moving body operating to change the driving state has a characteristic where the next operation of the mobile body can be determined only if the definition of the speed determination model (according to its functions) and the lane change decision are correctly preceded. Also, if all the moving bodies traveling on a general road are equipped with an autonomous driving function, it is difficult to consider the factors that may occur between each mobile unit from unexpected environmental changes. Considering these factors, we applied the decision model to the platform and studied the lane change decision system for implementation of the platform. We studied the decision model using a modular learning method to reduce system complexity, to reduce the learning time, and to consider model replacement.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.474-481
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• 2019

Korea entered the aged society in 2018 with the elderly population accounting for 14.4% of the total population, and it is expected to enter the super-aged society in 2026. In particular, it is predicted that by 2050, the elderly population will be 38% of the total population, making it one of the countries with the highest number of elderly people in the world. The increase in the elderly population is naturally leading to an increase in the number of traffic accidents among elderly drivers, in 2017, there were 26,713 elderly driver accidents over 65 years of age, with 848 people dying and 38,627 injured. Compared with 2011, the number of accidents and injuries has doubled and the number of deaths has increased 1.4 times. This study determined that the main factors of the increase in traffic accidents were the characteristics of elderly drivers, such as a decrease in visual/hearing ability, cognitive and information processing ability, and muscle strength. Therefore, it raised the necessity of autonomous vehicle(level 2) for elderly driver who can minimize the burden of driving and aimed to study the function of autonomous vehicle for elderly driver who is not familiar with new technology. Based on this, four functions of autonomous vehicles for elderly drivers were derived, such as providing clear information according to the road environment, considering physical characteristics of drivers, simplifying interface, and reinforcing in-vehicle safety devices.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.101-109
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• 2010

There are many slopes generally developed by excavation and cut slope with small steps on massive slopes of roads. Especially these cut slopes which excavating around fault fracture zone need a reinforcement technology in order to ensure safety. In the case of slope excavation, it is difficult to use the existing slope support at fracture zone because of geological characteristics. Especially the factor of safety decreases significantly due to the movement of blocks in bed rocks and the expansion of interspace of discontinuous planes in fractured zones caused by excavation. Thus an efficient reinforcement technique in accordance with geological properties of fracture zones needs to be developed because the existing slope support has a restricted application. Therefore it is necessary to develop the specialized rock bolt technique in order to ensure an efficient factor of safety for anomalous fracture zones in slopes and tunnels. The purpose of this study is to develop newly improved rock bolt to increase a supporting effect of the swellex bolt method used recently as a friction type in fracture zones.

• Journal of Environmental Impact Assessment
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• v.25 no.1
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• pp.1-14
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• 2016

With the continuous expansion of highway network and its traffics, neighboring wildlife habitats are splitted into smaller and more isolated patches. The infrastructures contribute to the wildlife-vehicle collision by creating barriers to animal movement. This kinds of traffic accidents are dangerous factors to the drivers' safety and the facilities on the highway as well as to the wildlife themselves. One of the most common ways to prevent habitat fragmentation are fauna crossings and fences. The cost of the mitigation measures to prevent wildlife-vehicle collision could be monetized. However their economic benefits are difficult to be measured. Using contingent valuation method, this study tries to estimate the economic valuation of wildlife collision prevention projects on the Korean highways. The result shows that 43.88% of Korean household had the positive willingness pay to the projects. Moreover, we found that the recognition of the project or the favourable attitude to the environmental issues could raise the willingness-to-pay. Therefore, active public relation on the project could make the friendly public opinion and increase the number of the household which has the positive willingness-to-pay on the project.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.323-336
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• 2015

Estimating the risks on the roadway using surrogate safety measures (SSM) has an advantage in that it focuses on the vehicle trajectory directly involved in conflicts. On the other hand, there is a restriction on estimating the risks of continuous segments due to the limited data collected from a location. To overcome the restriction, this study presents the scheme of acquiring the vehicular trajectory using real time kinematics-differential global positioning system (RTK-DGPS) and develops a methodology which contains the considerations of the problems to calculate the SSM such as time-to-collision (TTC), deceleration rate to avoid collision (DRAC) and acceleration noise (AN). By using the methodology, this study shows a result from an experiment executed in a section where the variation of vehicular movement can be observed from several continuous flow roadway sections near Seoul and Gyeonggi Province in Korea. The result illustrated the risks on the roadway by the SSM metrics in certain situations like merging and diverging, stop-and-go, and weaving. This study would be applied to relate the dangers with characteristics of drivers and roadway sections, and prevenst accidents or conflicts by detecting dangerous roadway sections and drivers' behaviors. This study contributes to improving roadway safety and reducing car-accidents.

• Journal of Korea Spatial Information System Society
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• v.7 no.2 s.14
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• pp.29-38
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• 2005

Even though underground conduits have became important city-infra structures which should be exhaustively and efficiently managed, there is few systems which supports the well-defined facility management standards. Due to the lack of the supporting systems, experts must visit underground conduits scattered several cities over the country to see and check the status of the underground conduits including built-in facilities. This type of management gives us a little bit delayed status information at the end of so much time and money costs. In this paper, to solve this problem and manage the conduit synthetically, we developed a web-based facility management system for underground conduits by using information technologies. The developed management system has a simplified map drawing interface to depict the overall architectures and locations of underground conduits and their built-in facilities into sketch maps. And, the system uses the 3D panorama image technology with zooming functions in addition to still images and video images to give the feeling of a spot inspection. Moreover, since the system accumulates the data of repair/reinforcement, occasional inspections and safety diagnosis, conduit managers can synthetically and effectively manage the facilities within underground conduits and themselves.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.19-28
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• 2012

In this study, cause of longitudinal crack which is found on duct slab of road tunnel is studied. In-depth investigation, such as visual inspection, non-destructive testing and geometrical surveying of duct slab, is carried out. In order to perform cause analysis, the investigated results are compared to the results of numerical analysis. Many factors, which cause longitudinal crack, are classified as constrained condition of the duct slab, location of the rebar, temperature, shrinkage and so on. According to the classified causes of longitudinal crack, numerical analysis is performed considering construction stage of the tunnel lining. Especially, in order to predict shrinkage stain due to discrepancy of curing date, ACI-209 model, KCI structural design code and other researcher's shrinkage test results are compared. The results show that shrinkage strain is one of the main factors causing longitudinal crack. Other investigated tunnels are classified along with the construction method of duct slab and patterns of cracks. As a result, improving ways to construct duct slab are suggested.

• Journal of Korean Society of societal Security
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• v.1 no.3
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• pp.59-67
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• 2008

The most influential facility causing traffic disaster on the urban road is intersection. Accordingly, this study elected a region for case study from seabang three-way junction, partial section of Dongmoon Ro in Kwang-Ju city, to the intersection of Mudeung Library Entrance. It is believed that the signal progression is very effective on the basis of short interval of intersection and massive traffic volume. The signal progression was simulated by using TRANSYT-7F model. The following is summary of the simulation: According to the change of cycle length, P.I. delay and fuel consumption showed the tendency of being increased in case that cycle length becomes long or short, centering around the best cycle length. In the event of progressing the cycle length, the average speed per vehicle is increased by 11.39Km per hour and P.I value is improved by 40.65% so that it resulted in 42.86% improvement in the total travel time. Moreover, the fuel consumption in line with the progression practice produced fuel saving of 31.04%.