• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.9-16
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• 2012

The dynamic stability of railway vehicle has been one of the important issues in railway safety. The dynamic simulator has been used in the study about the dynamic stability of railway vehicle and wheel/rail interface optimization. Especially, a small scale simulator has been widely used in the fundamental study in the laboratory instead of full scale roller rig which is not cost effective and inconvenient to achieve diverse design parameters. But the technique for the design of the small scale simulator about the dynamic characteristics of the wheel-rail system and the bogie system has not been well developed in Korea. Therefore, the research using the small-scaled derailment simulator and the 1/5 scaled bogie has been conducted. In this paper, we did running stability test of 1/5 scaled bogie using small-scaled derailment simulator. Also, for the operation of the small scaled simulator, it is required to investigate the performance and characteristics of the simulator system. This could be achieved by a comparative study between an analysis and an experiment. This paper presented the analytical model which could be used for verifying the test results and understanding of the physical behavior of the dynamic system comprising the small- scaled derailment simulator and the 1/5 scaled bogie.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.206-216
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• 2012

Today's war fields can be characterized by net-centric wars where a variety of independent weapon systems are operated in connection with each other via networks. As such, weapon systems become dramatically advanced in terms of complexity, functionality, precision and so on. It is then obvious that the defense R&D of those requires systematic and efficient development tools enabling the effective management of the complexity, budget/cost, development time, and risk all together. One viable approach is known to be the development methods based on systems engineering, which is already proved to successful in U.S. In this paper, a systems engineering approach is studied to be used in the conceptual design of advanced weapon systems. The approach is utilizing some graphical models in the design phase. As a target system, an unmanned aerial vehicle system is considered and the standard SysML is also used as a modeling language to create models. The generated models have several known merits such as ease of understanding and communication. The interrelationships between the models and the design artifacts are identified, which should be useful in the generation of some design documents that are required in the defense R&D. The result reported here could be utilized in the further study that can eventually lead to a full-scale model-based systems engineering method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.152-164
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• 2015

A rapid development of semiconductors, sensors and mobile network technologies has enable that the embedded device includes high sensitivity sensors, wireless communication modules and a video processing module for vehicular environment, and many researchers have been actively studying the smart car technology combined on the high performance embedded devices. The vehicle is increased as the development of society, and the risk of accidents is increasing gradually. Thus, the advanced driver assistance system providing the vehicular status and the surrounding environment of the vehicle to the driver using various sensor data is actively studied. In this paper, we design and implement the smart vehicular camera device providing the V2X communication and gathering environment information. And we studied the method to create the metadata from a received video data and sensor data using video analysis algorithm. In addition, we invent S-ROI, D-ROI methods that set a region of interest in a video frame to improve calculation performance. We performed the performance evaluation for two ROI methods. As the result, we confirmed the video processing speed that S-ROI is 3.0 times and D-ROI is 4.8 times better than a full frame analysis.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.18-25
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• 1998

According to the requirements of ANSI B3l.8, the pipe thickness is determined with hoop stress resulted from internal pressure. And the other loads induced by soil, vehicle, thermal expansion, ground subsidence, etc shall be evaluated rationally. There are two ways of calculating stress of buried gas pipeline. The first is FEM. FEM can calculate the stress regardless of the complexity of pipeline shape and boundary conditions. But it needs high cost and long time. The second is the way to use equation. The reliable equations to calculate the stress of buried gas pipeline was developed and have been used in designing pipeline and evaluating pipeline safety, But these equation are very difficult to understand and use for non-specialist. For easy calculation of non-specialist, the new computer program to calculate stress of buried natural gas pipeline have been developed. The stress is calculated by the equations and extrapolation of the graph resulted from FEM. The full paper is consist of series I and II. In this paper, series I, the calculating equation of the program is explained in detail.

• Smart Media Journal
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• v.11 no.5
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• pp.75-81
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• 2022

In order to respond to carbon neutrality and climate change in agriculture, agricultural machinery, which has been developed centered on internal combustion engines, needs to be converted to an electric-based technology that does not emit greenhouse gases. In this study, simulations for electric UTV suspension design were performed to reduce vibration and shock of electric UTV for agricultural use and to improve driving stability and control performance of the vehicle. The simulation was performed by dividing the tolerance load of the vehicle body and the loaded load state. The range of motion of the suspension spring of UTV is within 30% of the range of motion under condition B under tolerance, the displacement of the UTV suspension with full load is reduced from 264mm to 121mm, and the damping speed is 260mm/s to 300mm/s that it can be seen that the range of motion is within 60%. Suspension design of electric UTV for multi-purpose agricultural work is a very important factor for maintaining agricultural work ability in towing work such as tillage as well as driving and terrain adaptation. The results of this study can be usefully used to determine the spring parameters with the appropriate damping range so that the electric UTV can be used for various agricultural tasks.

• Journal of Korean Society of Disaster and Security
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• v.16 no.2
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• pp.75-83
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• 2023

In general, bridges are facilities installed for the purpose of easily passing through sections such as valleys and rivers. Railway bridges that run through downtown areas are damaged due to external factors such as earthquakes and collisions with passing vehicles, resulting in serious human casualties. This can cause serious human and properties damage, such as functional paralysis in downtown areas. Depending on the degree of damage, repair work such as partial repair or full replacement is in progress for the bridge where the collision occurred. When damage or deformation occurs due to collision, the repair method is determined according to the degree of deformation and the degree to which the load capacity of the bridge is affected by the deformation. In this study, a numerical analysis review was performed on the repair work for the local deformation caused by the collision of a vehicle on an old railway bridge installed and in operation in an urban area. To this end, a structural safety review of the bridge for local deformations caused by vehicle collisions was conducted. In this paper, a repair method for the accident bridge was presented based on the analysis results.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.1-15
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• 2020

This study examined the factors that influence creative performance in corporate collaboration projects. Specifically to facilitate team collaboration, we identified that scaffolding, which is one of the important factors in organizational learning communication, and the Boundary Objects, which are collaboration tools & vehicle, influence performance. The survey was collected for 203 employees who experienced collaborative projects, and three-step mediated regression analysis was conducted after conducting exploratory factor analysis. In other words, we examined the median effect of boundary objects on the impact of scaffolding on creative collaborative performance. Analysis showed that while the effects of the boundary objects in relation to the impact of cognitive scaffolding on creative performance were not significant, emotional scaffolding had a full-scale effect on the creative performance and also had a full-scale effect on the efficacy performance. Given these results, it is necessary to share a vision and form personal relationships among team members in order to activate them, since scaffolding is useful in organizational learning and boundary objects also have some effect as a medium for promoting collaboration in projects.

• Fire Science and Engineering
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• v.28 no.3
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• pp.72-79
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• 2014

The purpose of this study is to draw the improvement plan through the analysis of problems of main stretchers that are being used by the 119 EMS. In order to find out the problems, we used the literature review and analysis, survey questionnaire and we also made full use of KJ method (Kawakita Jiro method, affinity diagram), graph method, and priority matrix method to produce the improvement indicators. The problems of main stretchers are summarized as follows. they are being recognized as part of the emergency vehicle, they have the imperfection of performance verification criteria, and they cause the injuries of paramedics and patients accidents in operation. The indicators such as the ease of operation, the high performance, the multi-function, the driving performance, the durability and the lightweight, was produced to improve the problems. The results of the interconnection analysis and the applying priority matrix method on the indicators are the ease of operation ${\rightarrow}$ the multi-function ${\rightarrow}$ the driving performance ${\rightarrow}$ the high performance ${\rightarrow}$ the durability and the lightweight in order of importance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.49-61
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• 2015

This is the second of two companion papers that describe the performance assessment for flexible rockfall protection systems. Described in a companion paper is the criteria to assess the performance of flexible rockfall protection systems. In this study the performance assessment of domestic rockfall protection fences was implemented using the criteria suggested in the companion paper. It was investigated that the rockfall protection fences for express highways performed well to resist the rockfall energy of 50kJ and the deformed rockfall protection fences right after impacting would not obstruct the vehicle traffic. However, to dissipate the rockfall energy of 50kJ with the level of European standards constantly, the spacing of wireropes was adjusted to be 200mm up to the 8th wirerope from the bottom and spacing-maintainers should be extended to the 8th wirerope. It was figured out that the rockfall protection fences for general highways were required to install spacing-maintainers as those for express highways because they, which did not have spacing-maintenance members, were very prone to the penetration of rockfall even for the very small rockfall impact energies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.63-76
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• 2015

The purpose of this study is to suggest performance levels, a test method, and assessment criteria for the performance assessment to allow standardized tests for rockfall protection systems. The range of rockfall impact energy was determined by using domestic rockfall data and a total of 9 performance levels from 50kJ to 1500kJ were suggested. The performance assessment is implemented by two types of full-scale free-fall impact tests to investigate the serviceability and the maximum capacity as in European and American standards. It was considered to be reasonable that the specimens of rockfall protection systems consist of 3 spans and the concrete block of a polyhedron with 26 faces, similar to spheres, impacts at the center of a center span. Assessment criteria were constructed to investigate whether a rockfall penetrated rockfall protection systems and whether the deformed specimen encroached on the roadway or obstructed the vehicle traffic.