• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.675-687
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• 2019

In recent years, the needs for double deck-tunnels have increased in large cities due to the increase in traffic volume and high land compensation costs. In Korea, a network type tunnel which is smaller than general road tunnels and crosses another tunnel underground is planned. In the shield tunnel joints between the existing shield tunnel and the box-type enlargement section, a partial steel-concrete joint is proposed where the bending moment is large instead of the existing full-section steel joint. In order to analysis the enlargement section of the shield tunnel diverged section to reflect the three-dimensional effect, the two-dimensional analysis model is considered to consider the column effect and the stiffness effect of the longitudinal member. A two-dimensional analysis method is proposed to reflect the stiffness of the longitudinal member and the column effect of the longitudinal point by considering the rigidity of the longitudinal member as the elastic spring point of the connecting part in the lateral model. As a result of the analysis of the model using the longitudinal member, it was considered that the structural safety of the partial steel-concrete joint can be secured by reducing the bending moment of the joint and the box member by introducing the longitudinal member having the stiffness equal to or greater than a certain value.

• Convergence Security Journal
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• v.17 no.5
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• pp.143-151
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• 2017

The purpose of this study is to provide the future development of the PRC Marine Corps by analyzing the changing functions via its historical development. The PRCMC is an elite regular military forces and was established by the Central Military Commission(China) in 1953 in order to project the national military power toward the enemy's territory by overcoming maritime obstacles such as seas and lakes. The PRCMC is relatively smaller personnel strength compared with the whole size of the PRC military forces. Thus its functions were limited in the areas of amphibious and land operations, island and land defense against Taiwan before the PRC pursues expanding policy toward outside. However, in the 2000s, China pursues its policy for obtaining absolute national interest so that its functions are rapidly enlarged into defense of the forward naval bases, and those for evolving its power toward outside according to not only the island territorial dispute with Japan, but also Xi Jinping's active expanding policy what we call 'the one belt and one road'. So its personnel strength is slowly increased. If the increasement of the PRC Navy and Marine Corps would develop into the level of which they can contain the status and influence of the US military power in Asia-Pacific area, it is possible that the security environment of the North-east Asia including the Korean peninsula will be fluctuated. Consequently, the ROK also needs to reevaluate the functions and the size of the joint strength of the ROK Navy and Marine Corps considering the transition of the changing security environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.4
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• pp.505-512
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• 2019

This study is a basic study to prepare safety measures for the tram that is being introduced into Korea by reviewing accident analysis and accident compensation system of the tram. Analysis of accident characteristics of the tram was analyzed based on overseas data. Five years after the inauguration of the tram, accidents were halved and stabilized. Deaths accounted for 0.5 % of all casualties, most accidents were minor. Accidents with other mean transportation were high 84.1 %, among them accidents with passenger cars was found to be highest. The frequent points of accidents were analyzed as intersections and tram stop, and measures for pedestrian accidents were found to be important. Those are proposed safety measures through analyzing tram accident characteristics: Monitoring accidents which occur within five years of its inauguration, developing accident database input system, installation of fences for preventing people from jaywalking, operating traffic signal for preventing people from jaywalking through connection of pedestrian signals and tram signals, clamping down on illegal U-turn cars and jaywalking pedestrian, Also, those are proposed accident treatment measures based on general driver receptively and overseas data: property damage liability coverage (PI) of car insurance, comparative negligence when the accident occurs between car and tram.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.13-19
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• 2019

This paper analyzed the SCMS and pilot policy, which is pursued by the U.S. government in connected vehicles. SCMS ensures authentication, integrity, privacy and interoperability. The SCMS Support Committee of U.S. government has established the National Unit SCMS and is responsible for system-wide control. Of course, it introduces security policy, procedures and training programs making. In this paper, the need for SCMS to be applied to C-ITS was discussed. The structure of the SCMS was analyzed and the U.S. government's filot policy for connected vehicles was discussed. The discussion of the need for SCMS highlighted the importance of the role and responsibilities of SCMS between vehicles and vehicles. The security certificate management system looked at the structure and analyzed the type of certificate used in the vehicle or road side unit (RSU). The functions and characteristics of the certificates were reviewed. In addition, the functions of basic safety messages were analyzed with consideration of the detection and warning functions of abnormal behavior in SCMS. Finally, the status of the pilot project for connected vehicles currently being pursued by the U.S. government was analyzed. In addition to the environment used for the test, the relevant messages were also discussed. We also looked at some of the issues that arise in the course of the pilot project.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.34-48
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• 2019

The purpose of this study was two-fold; first, to develop safety performance functions (SPF) using transportation-related big data for all types of roads in Korea were developed, Second, to provide basic information to develop measures for relatively dangerous roads by evaluating the safety grade for various roads based on it. The coordinates of traffic accident data are used to match roads across the country based on the national standard node and link system. As independent variables, this study effort uses link length, the number of traffic volume data from ViewT established by the Korea Transport Research Institute, and the number of dangerous driving behaviors based on the digital tachograph system installed on commercial vehicles. Based on the methodology and result of analysis used in this study, it is expected that the transportation safety improvement projects can be properly selected, and the effects can be clearly monitored and quantified.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.93-113
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• 2019

The behavior of the 3 hinged precast arch structure was investigated by comparing field measurements with numerical analyses performed for precast lining arch structures, which are widely used for the open-cut tunnel. According to the field measurements, the maximum vertical displacement occurred at the crown with upward displacements during the backfilling up to the crown of the arch and downward displacements at the backfill height above the crown. The final crown displacement was 19 mm upward from the original position. The horizontal displacement at the sidewall, which had a maximum horizontal displacement, occurred inward of the arch when compacting the backfill up to the crown and returned to the original position after completing the backfill construction. According to the analysis of displacement measurements, economical design is expected to be possible for precast arch structures compared to rigid concrete structures due to ground-structure interactions. Duncan model gave good results for the estimation of displacements and deformed shape of the tunnel according to the numerical analyses comparing with field measurements. The earth pressure coefficients calculated from the numerical analyses were 0.4 and 0.7 for the left and the right side of the tunnel respectively, which are agreed well with the eccentric load acting on the tunnel due to topographical condition and actual field measurements.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.701-714
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• 2018

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.27-35
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• 2019

The purpose of this study is to analyze the displacement characteristics in slow-moving landslide area using digital elevation model and airborne LiDAR when unpredictable disaster such as slow-moving landslide occurred. We also aimed to provide basic data for establishing a rapid, reasonable and effective restoration plan. In this study, slow-moving landslide occurrence cracks were selected through the airborne LiDAR data, and the topographic changes and the scale of occurrence were quantitatively analyzed. As a result of the analysis, the study area showed horseshoe shape similar to the general form of slow-moving landslide occurrence in Korea, and the direction of movement was in the north direction. The total area of slow-moving landslide damage was estimated to about 2.5ha, length of landsldie scrap 327.3m, average width 19.3m, and average depth 8.6m. The slow-moving landslides did not occur on a large scale but occurred on the adjacent slope where roads were located, caused damage to retaining walls and roads. The field survey of slow-moving landslides was limited by accessibility and safety issues, but there was an advantage that accurate analysis was possible through the airborne LiDAR. However, because airborne LiDAR has costly disadvantages, it has proposed a technique to mount LiDAR on UAV for rapidity, long-term monitoring. In a slow-moving landslide damage area, information such as direction of movement of cracks and change of scale should be acquired continuously to be used in restoration planning and prevention of damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.502-509
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• 2019

Studies have been made on performance evaluation of expansion joint systems for an ordinary highway or road bridge. However little study has been made for runway connection bridges at airports. A study on performance evaluated from computer code analysis and shrinkage, extension, and compression repetition tests based on KS F 4425 is conducted to a newly developed expansion joint system which has been installed in a runway connection bridge at Incheon Airport Extension 2 Construction Site. The MIDAS computer code is used to analyze the performance before the manufacture of the mock-up of expansion joint system on the basis of design requirements. Tests based on the KS F 4425 of 2001 year-version are conducted for the mock-up. Domestic codes and standards to validate the performance of the expansion joint system in a connection bridge have been developed for a vehicle. However the expansion joint system tested in this study is installed in a runway connection bridge for an aircraft. Conservatively the heaviest one among airplanes departing and landing at Incheon Airport is assumed level-F $468.4kN/m^2$ and adopted for the tests and analyses in this study. KS F 4425 method is selected for the shrinkage, extension, and compression repetition tests. No remarkable problem was observed for the 2,500-cycle shrinkage and extension and two million-cycle repeatition load tests. The results of this study are expected to contribute to establishment of code and standard for the performance validation of an expansion joint system installed in a runway connection bridge for an aircraft by providing performance test results and computer analysis results based on finite element methods.

• Composites Research
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• v.32 no.1
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• pp.21-28
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• 2019

Recently, according to environmental regulations, the automobile industry has been conducting various research on the use of composite materials to increase fuel efficiency. However, there has not been much research on lightweight chassis components. Therefore, in this research, the purpose of this study is to apply composite materials to the sub-frame of chassis components to achieve equivalent levels of stiffness, strength, NVH performance and 50% lightweight compared to the steel sub-frame. First, the Natural frequency of steel and composite specimens was compared to the damping characteristics of composite materials. Then, in this study, the Lay-up Sequence was derived to maximize the stiffness and strength of the sub-frame by applying composite materials. And this lay-up Sequence is proposed to avoid heat shrinkage due to curing during manufacturing. This process was designed based on a FEM structural analysis, and a Natural frequency and frequency response function graph was confirmed based on a modal analysis. The prototype type composite sub-frame was manufactured based on the design and the F.E.M analysis was verified through a modal experiment. Furthermore, it was fitted to the actual vehicle to verify the natural frequency and the indoor noise vibration response, including idling and road noise. This result was confirmed to be equivalent to the steel sub-frame. Finally, the composite sub-frame weight was confirmed to be about 50% of the steel sub-frame.