• Proceedings of the KSR Conference
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• 2008.11b
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• pp.66-72
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• 2008

In this study, transient 3D numerical simulations were performed to analyze the characteristics of fire driven flow for smoke ventilation system operating conditions in the deeply underground subway station. The smoke flow patterns were compared and discussed under smoke fan operating mode and off mode in the platform. Soongsil Univ. station(line number 7)was chosen for simulation which was the one of the deepest underground subway stations in the each lines of Seoul. The geometry for model is 365m in length include railway, 23.5m for width, 47m for depth. Therefore 10,000,000 structured grids were used for fire simulation. The parallel computational method for fast calculation was employed to compute the heat and mass transfer eqn's with 6 CPUs(Intel 3.0GHz Dual CPU, 12Cores) of the linux clustering machine. The fire driven flow was simulated with using FDS code in which LES method was applied. The Heat release rate was 10MW and The Ultrafast model was applied for the growing model of the fire source.

• Journal of the Korean Society for Railway
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• v.11 no.5
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• pp.513-518
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• 2008

Currently, urban areas face congestion problems that diminish personal mobility and freight-transport productivity. An increasing number of experts suggest that separating freight traffic from passenger traffic makes sense in terms of economics, the environment, and safety. Some experts suggest that tube transportation is the solution. The objective of this paper is to evaluate the potential benefits and limitations of tube transportation system as a viable mode of transport that can alleviate congestion on roadways. Specifically, this research employs theoretical and practical method identifying, evaluating, and selecting appropriate freight pipeline systems; evaluating the technical and economic feasibility of tube transportation; and estimating environmental, energy, and safety benefits.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1810-1815
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• 2011

Although the effectiveness of an express train's service is measured in "Total System Time or Cost" units, many cases had used indirect method what based on the distintion by number of passengers in a station or experiential knowledgements. These methods are not guarantee itself as an optimal strategy. Focusing "Total System Time or Cost" directly, this paper investigates the express train service's stop scheduling based on each OD-volume and trip time which mainly affect system time and cost. To do this, we built an IP model which has a binary set presenting express train's stop scheduling as decision variable and suggest a Genetic Algorithm (GA) to find heuristic optimal solution.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.409-414
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• 2003

In this study we examined the method to select the size of the conductor rail for light rail system. Study results shows that using the conductor rail with lower resistivity requires fewer power substation, which results in lower construction cost. It also produces less copper loss. Therefore first choose the conductor rail with lowest resistivity and select the substation location, Next conduct computer simulation study to confirm it meets voltage requirement. if the minimum voltage is well above the required minimum voltage, substation number can probably be further reduced.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.349-355
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• 2010

The purpose of this paper is to provide basic information on how to make better policies that improves efficiencies and to derive policy directions using DEA (data envelopment analysis) model. Through this paper, we can identify whether or not the railroad service has an excellent performance, if there are any structural problems, in which sector it is experiencing a degree of inefficiency, and, therefore, how to set up a realistic target to improve efficiency of railroad transportation. According to the result, we need to introduce a better resource efficient economic strategy to reduce the rail line extension and the number of passenger cars for better efficiency from a public interest perspective, while to widen headways and/or reduce the rail line extension from an economic point of view.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.211-215
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• 2008

Generally, an EMU (Electronic Multiple Unit) is manufactured by assembling a large number of components and parts with extensive raw materials. Throughout its entire life cycle, much both the complicated system and long operating period. Therefore, it is necessary to the environmental performance of EMUs from raw materials to waste. In this study, RACE (Rail Assessment for Clean Environment) was developed as the software that can analyze the environmental RACE had several LCI (Life Cycle Inventory) database for main components as well as principal materials in EMUs. In the future, RACE can also be used as a tool for environmental communication between manufacturers and operators. Also, we will improve RACE continuously to assess more easily the environment of rolling stocks EMU for user.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.481-488
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• 2015

The recent trend in transportation planning information is to reduce traffic survey costs and enhance accuracy by using and converging various sources of external data. In Korea, mobile phone data can help generate useful transportation planning information, thanks to the universal use of mobile phones, which are present in a number greater than that of the population. This paper addresses measures to derive trip generation information from mobile phone data and verifies the value of the system for practical use by correlation analysis with KTDB trip generation data. The results show that trip generation information produced by mobile phone data correlates with existing (KTDB) trip generation data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.65-70
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• 2000

Flying an aircraft is not like driving a train along a railway track. There are many factors that may affect an aircraft's course, including the wind speed and direction relative to the aircraft's intended flight path. This paper investigates noise exposed area by using INM. Especially, effect on aircraft route to minimise the number of people overflown by departing aircraft is evaluate. The result shows that track keeping scheme is effective to reduce the noise area. On the other track at 4000ft is negligible to the noise contour.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.79-88
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• 2008

Recently, the high speed railway comes into the spotlight as the important and convenient traffic infrastructure. In Korea, Kyung-Bu high speed train service began in bout 400 km section in 2004, and the Ho-Nam high speed railway will be constructed by 2017. The high speed train will run with a design maximum speed of 300-350 km/hr. Since the trains are operated at high speed, the differential settlement of subgrade under the rail is able to cause a fatal disaster. Therefore, the differential settlement of the embankment must be controlled with the greatest care. Furthermore, the characteristics and causes of settlements which occurred under construction and post-construction should be investigated. A considerable number of studies have been conducted on the settlement of the natural ground over the past several decades. But little attention has been given to the compression settlement of the embankment. The long-term settlement of compacted fills embankments is greatly influenced by the post-construction wetting. This is called 'hydro collapse' or 'wetting collapse'. In spite of little study for this wetting collapse problem, it has been recognized that the compressibility of compacted sands, gravels and rockfills exhibit low compressibility at low pressures, but there can be significant compression at high pressures due to grain crushing (Marachi et al. 1969, Nobari and Duncan 1972, Noorany et al. 1994, Houston et al. 1993, Wu 2004). The characteristics of compression of fill materials depend on a number of factors such as soil/rock type, as-compacted moisture, density, stress level and wetting condition. Because of the complexity of these factors, it is not easy to predict quantitatively the amount of compression without extensive tests. Therefore, in this research I carried out the wetting collapse tests, focusing on various soil/rock type, stress levels, wetting condition more closely.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.38-45
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• 2016

For higher efficiency and reliability of railroad trains with many electronic sensors and actuators, a distributed control system with which electronic components communicate with each other in a distributed manner via a data network is considered. This paper considers Ethernet-based Train Communication Network (TCN) for this purpose and proposes a methodology to optimize the topology in terms of transmission latency and reliability, each of which is modeled as the number of traversing backbone nodes and the number of cables between vehicles, respectively. An objective function is derived accordingly and a closed-form optimum is obtained by relaxing the integer constraint of the number of vehicles for a unit network. Then, the final integer optimum is searched around it. Through numerical evaluation, the validity of the proposed methodology and the characteristics of the resulting solutions are shown.