• Proceedings of the KOR-KST Conference
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• 1998.09a
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• pp.185-191
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• 1998

Metro, as a kind of city rail transit, is a modem city passenger transit system with mass transportation and independent special rails. It has become a backbone of the traffic in the metropolis and an important modern symbol of a city. A modem traffic system is indispensable for Shanghai to be an international metropolis of finance, trade and economy. At present, Shanghai metro line No. 1 and its extension have been put into operation, metro line NO. 2 will be put into trial operation by the end of 1999, the Pearl Line, an elevated rail transit system is under construction and other lines will be constructed later according to the plan. But the funding of the city rail transit construction (both metro and light rail) is a big difficult problem to the infrastructure construction of the metropolises either at home or abroad, which is also a problem to restrict the development of the city rail transit of Shanghai. We have learned from the internal and external experiences of the rail transit construction that it is an important means to deal with the funds of the city rail transit construction to actively utilize foreign funds. It makes up the shortage of the internal funds on the one hand, the external advanced science and technology and the management experiences can be introduced on the other hand. In order to discuss and study conveniently with you together the new problems appearing in the metro construction and to open up a new train of thought, this article will give out a certain analysis and description to the funding method in the metro construction of Shanghai and the characteristics of utilizing foreign funds in the rail transit construction as well as the problems which we are faced with.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.279-286
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• 2018

Recently, a safety control platform to monitor the safety of train operation in real time and prevent accidents and risks through control is under study. In the initial design, DDS communication method supporting distributed network is adopted for real-time processing of large amount of data according to the integration of existing distributed safety data. However, communication between server and console inside the safety control platform is applied to existing TCP socket communication. In the case of TCP socket communication, it is possible to process data for a small system of a safety control test bed by one-to-one communication. However, if the data is expanded all over the country in the future, it becomes difficult to cope with a case where communication traffic occurs due to vast amount of data. In this paper, we propose DDS communication method to support distributed network between server and console of security control platform, and demonstrate TCP socket and DDS method, and compare throughput and speed. As a result, we have found that the scalability and flexibility are improved in case of applying DDS communication to future systems.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.151-163
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• 2021

This paper is dealt with railway slope stability for slope reinforcement using a geosynthetic concrete composite mat(GCCM). Recently, according to a change in weather caused by global warming, train operation has been restricted by the loss of backfill slope at the roadbed, which is consists of gravel, due to typhoons and heavy rainfall. In addition, the amount of damage is getting more significant than the cost of restoration, and the safety of workers is worried. In order to improve this limitation, a slope stability analysis was applied with a rapid hardening composite mat so that it can quickly secure a construction surface with increased workability and work stability and reduce maintenance costs by preventing re-loss in case of heavy rain and fundamentally blocking vegetation. As a result of the analysis, it was confirmed that the increase in safety factor was confirmed when the rapid harding composite mat was applied.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.40-48
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• 2022

Recent studies have reported about UAV-based disaster rescue system adopting AR technology. Performing a disaster rescue training in an environment similar to an actual disaster site results in high costs and risk of accidents. In this paper, we propose a simulation software using VR technology so that rescuer can safely and inexpensively train the operation of the disaster rescue system. Through the analysis of the existing system, we derived the requirements for virtualizing training, and developed the simulation software using Unreal Engine and Airsim API. Simulation results show that the proposed simulation software can effectively simulate the operation of the conventional disaster rescue system.

• Journal of the Korea Society of Computer and Information
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• v.28 no.7
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• pp.1-9
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• 2023

Currently, as the demand for stops in the urban increases resulting from an increase in the supply of express trains, the development of trains capable of operating both high-floor platforms in the urban and low-floor platforms in the suburbs is required. In this paper, we studied the design and fabrication of a controller for train doors that consists of low and high steps as a plug-in type door mechanism and thus can be used on low and high platforms. This DCU H/W was designed and implemented using 32 bit MCU to control 4 motors, 33 digital inputs and 16 digital outputs. In addition, based on the software life cycle of EN50128, 2 items of operation requirements and 12 items of control requirements were derived, and then they were designed and implemented as operation SW. The implemented SW was tested for each requirement. As a result, we performed tests on 13 items that could be tested in the mock-up out of 14 total requirement items and showed that the requirements were satisfied.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.65-70
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• 2013

In many cases, operation of regional trunk lines is not profitable to railway operators. Nevertheless, railway operators are under pressure to manage regional trunk lines running under deficits, to better serve public interests. Given this situation, railway operators need to optimize assets by adjusting train schedules or changing the number of trains running. When railway operators judge the operation of a regional trunk line, the B/C ratio is generally used as a management index. This ratio is not considered part of strategic operational policy over the long term, and excessively influenced by the aspects of supply and demand over the short term. Accordingly, this study focused on indices that might be used to prevent worsening deficits and provide long term strategic operation policies, main indices to better measure economic situations, and auxiliary indices to supplement the main index. The main indices were measured in conventional ways to target experts and employees. This study presents quantitative standards, which are intended to be used to create itemized criteria through an Analytic Hierarchy Process, for better decision-making.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.101-112
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• 1999

Traffic accidents increase with the increase of the vehicles in operation on the street. Especially big traffic accidents composed of over 3 killed or 20 injured accidents with the property damage become one of the serious problems to be solved in most of the cities. The purpose of this study is to build the discrimination model on big traffic accidents using the Quantification II theory for establishing the countermeasures to reduce the big traffic accidents. The results are summarized as follows. 1)The existing traffic accident related model could not explain the phenomena of the current traffic accident appropriately. 2) Based on the big traffic accident types vehicle-vehicle, vehicle-alone, vehicle-pedestrian and vehicle-train accident rates 73%, 20.5% 5.6% and two cases respectively. Based on the law violation types safety driving non-fulfillment center line invasion excess speed and signal disobedience were 48.8%, 38.1% 2.8% and 2.8% respectively. 3) Based on the law violation types major factors in big traffic accidents were road and environment, human, and vehicle in order. Those factors were vehicle, road and environment, and human in order based on types of injured driver’s death. 4) Based on the law violation types total hitting and correlation rates of the model were 53.57% and 0.97853. Based on the types of injured driver’s death total hitting and correlation rates of the model were also 71.4% and 0.59583.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1533-1538
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• 2011

The dynamic characteristics such as resonant frequencies and dampings have been utilized as important parameters in dynamic behavior and inverse analyses. In general, the dynamic parameters have been determined based on design and experimental data, but experimental studies on the time-dependent changes of the dynamic parameters during service have rarely been conducted. Especially, unlike highway bridges, it is much easier for railroad bridges to estimate accumulated amount of fatigue because of the controlled train operation, and the study of dynamic characteristic change due to fatigue is useful, since it can enhance the accuracy of dynamic analysis. In this paper, the dynamic characteristic change due to fatigue is measured via the modal test on the PSC girder during a fatigue test. The test specimen utilized in the test is the IT girder which enhances the sectional capacity of the conventional PSC girders. The test specimen is designed 10m long and the modal tests are conducted during the application of fatigue load two million times. The test result shows that considerable changes in the measured dynamic parameters are observed as the fatigue accumulates, and these changes during the service life should be considered in designing railroad bridges.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.957-965
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• 2011

Recently, railway industry has been developed not only functional parts such as acceleration and high performance of the railway but also emotional parts such as improved ride comfort and blocking noise. However, some important components of railway such as wheel and rail always had exposed too much operation time, cyclic load and rolling contact directly. The variations of load, vibration and chemical compositions were caused of wheel and rail having a lot of different types of contact fatigue damages. Therefore, It is necessary to improve inspection and maintenance technology in order to ensure safety and reliability of railway. Many researchers have already been reported the technology. Magnetic camera, one of the non-destructive testing technique can be used to inspect and evaluate the changes of magnetic field in ferromagnetic and paramagnetic materials with cracks. When an electromagnetic is applied to a specimen, a magnetic field will be distorted around a crack on the specimen. In present paper, the distribution of magnetic property in wheel with cracks using magnetic camera had investigated. The crack can be detected and evaluated by distribution analysis of magnetic field. The magnetic camera technique can be detected and evaluated the crack by rolling contact fatigue.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.2
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• pp.225-232
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• 2013

In this paper, the study was conducted on the subject of the hybrid electric vehicles used by the military, and optimized the propulsion system for fuel economy considering energy supply to the mission equipments. For the analysis of the vehicles, a method based on the geometry and some assumptions was applied with basic vehicle dynamics. The sources of energy supply in the military hybrid electric vehicles are an engine, a battery and an ultra-capacitor. The optimal operation point among an engine, a battery and an ultra-capacitor can be found by minimizing energy consumption of driving power train and mission equipments. In the study, it was possible to find the optimal propulsion system by comparing fuel efficiency of the vehicles during the driving cycle.