• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.374-390
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• 2015

This research shows the relationship between the number of trains and the probability of trains with arrival delay and suggests way to estimate the benefits of improved punctuality in a bottleneck section of the Gyeongbu Line. The arrival delays of high-speed and conventional trains were estimated using the train operation data of KORAIL. Linear regression models for the probability of trains with arrival delay by train type are presented in this paper. The probabilities of trains with arrival delay were more affected by the number of conventional trains than by the number of high-speed rail trains. For the empirical analysis, a project for increasing the capacity in the Seoul~Geumcheongu office section was tested. The benefits of the improved punctuality were estimated to be 4.2~4.5 billion Korean won every year. This research has some limitations but it can help evaluate more precisely the feasibility of the project of increasing the capacity in bottleneck sections.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.27-37
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• 2010

Woven geotextiles (polyester mats) reinforcement is generally used to improve traffic ability, bearing capacity, and slope stability for embankment construction on soft ground. Cases of two high-strength woven geotextiles reinforcement layers are introduced in the present paper, which has been successfully constructed for rail road embankment on soft ground. According to the case results based on the limit equilibrium analyses of slope stability, the two high-strength woven geotextiles reinforcement layers on the soft ground can substantially increase the stability of the embankment by about 25%, improve the safety factor from 0.91 to 1.14, and significantly reduce the embankment construction duration at least 2 months. Therefore, the application of high-strength woven geotextiles is found to be useful for in-situ cases having the lack of construction duration and stability, as a soft ground improvement.

• Journal of Korean Society of Transportation
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• v.34 no.5
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• pp.465-475
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• 2016

Since inaccurate demand estimation for recent urban rail construction may result in financial burden to cities, precise prediction for operating cost as well as construction costs is necessary to avoid or reduce budget loss of the local or central government. The operating cost is directly related to the public fare and affect a policy to determine the rate system. Therefore, there is a pressing need to develop an estimating model for reliable operating cost of urban railway. This study introduces a new model to estimate the operating cost with new variables. It provides a better prediction in accuracy and reliability compared to the existing model, considering the feature of urban railway. For verification of our model, railway operation data from a few cities for the last five years were comprehensively examined to determine variables that affect the operating cost. The operating cost was estimated in a dummy regression model using five independent variables, which were average distance between stations, daily trains distance, total passenger capacity of a train in a train, driving mode(manned/unmanned), and investment type(financial/private).

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.228-238
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• 2010

There is an increasing interest in research to help overcome the energy crisis that has been focused on energy storage applications in various parts of power systems. Energy storage systems are good at enhancing the reliability or improving the efficiency of a power system by creating a time gap between the generation and the consumption of power. As a contribution to the various applications of storage devices, this paper describes a novel algorithm that determines the power and storage capacity of selected energy storage devices in order to improve upon railroad system efficiency. The algorithm is also demonstrated by means of simulation studies for the Korean railroad lines now in service. A part of this novel algorithm includes the DC railroad powerflow algorithm that considers the mobility of railroad vehicles, which is necessary because the electric railroad system has a distinct distribution system where the location and power of vehicles are not fixed values. In order to derive a more accurate powerflow result, this algorithm has been designed to consider the rail voltage as well as the feeder voltage for calculating the vehicle voltage. By applying the resultant control scheme, the charging or discharging within a specific voltage boundary, energy savings and a substation voltage stabilization using storage devices are achieved at the same time.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1071-1081
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• 2022

As the demand for high-rise buildings increases, the demand for high-speed elevators is also increasing. In order to make a high-speed elevator, a method is needed to reduce the weight of the elevator's components, which is a constraint on the increase in speed. As a measure to reduce the weight, it is possible to remove the traveling cable for power and signal supply. Since the weight of the traveling cable varies depending on the position of the carriage, it is difficult to compensate the weight using the counter weight. The power supply is a structure in which a brush-rail type power input terminal is installed in the elevator hoistway to receive power in a contact-type manner while the carriage is moving. If a small-capacity ESS is installed in a passenger car, power can be supplied uninterruptedly inside the passenger car. A small-capacity ESS charging system to be applied to such an elevator system is required to perform several functions. First, the passenger Car must be able to charge as much as possible even during high-speed operation. A control algorithm with high responsiveness is required because charging starts and ends repeatedly by the partially installed input power stage. In addition, if the input-side line impedance is large due to the structure of the system and the response characteristic is increased, the stability of the system may be lowered. Accordingly, in this paper, we propose a control algorithm that has a stable steady-state output while having a fast response in a transient state. To verify the proposed control algorithm, simulation was conducted using PSIM, and the performance of the controller was verified by manufacturing a prototype buck conveter charger.

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.33-40
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• 2007

Engineering behaviour of uplift-resisting ground anchors constructed in weathered rocks has been investigated by carrying out a series of full scale pull-out tests. The anchor was to resist uplift forces (buoyancy) associated with high groundwater table acting on the basement of a rail way station. The study has included the ultimate pull-out capacity of the anchors and shear stress transfer mechanism at the anchor-ground interface. The pull-out tests were conducted by changing bonded lengths of the anchor (2~7 m) and diameter of drilled borehole (108~165 mm) to investigate their effects on the behaviour of the anchor. The measured results showed that the ultimate capacity of the anchors was increased with an increase in the bonded length, diameter of drilled borehole as expected. The ultimate capacity of the anchors deduced from the pull-out tests ranged from 392 to 1,569 kN, depending on the above-mentioned factors. This corresponds to the interface shear strength of about 227~505 kPa. Interface shear stresses deduced from the pull-out test showed that the larger the pull-out force, the larger the mobilisation of the interface shear strength. The failure mode of the anchors heavily depended on the bonded lengths of the anchors. When the bonded length was short (2~3 m), a cone-type failure was observed, whereas when the bonded length increased (5~7 m), failure developed at the grout-ground interface.

• Journal of Power System Engineering
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• v.20 no.4
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• pp.19-25
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• 2016

It is needed to use the gait training system for the rehabilitation of the disabled and old people. In this study, a gait training system of turn roller type is proposed for the purpose of helping the rehabilitation. A driving mechanism with the turn roller is designed by using the RecurDyn which is the dynamic analysis program. RecurDyn is used to analyze the dynamic behavior of the gait training system. The static load analysis is carried out to investigate the safety of this system. From the operating test of this system, it is noted that the driving error is little and the load capacity is 130 kgf.

• Journal of Navigation and Port Research
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• v.29 no.3 s.99
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• pp.291-298
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• 2005

In this article. the specifications of a future container crane for a 18,000 TEU megaship are investigated After studying the transitions of containerships through the past half century, the characteristics of the past and current container cranes are outlined. together with various research trends throughout the world Upon these results, the size and performance of the container crane that will be used beyond the year 2014 are forecast. Specifically, the structure, trolley and hoist mechanism, control method, outreach. backreach, rail gage, loading capacity, stability, durability, and others are summarized.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1173_1174
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• 2009

Recently, the influence of electromagnetic environment for low frequency range on human body has been being argued. Light Rail Transit (LRT) System is an urban transit system which has approximately an intermediate transportation capacity between conventional subway and bus. The LRT systems have been applied and being operated in about a hundred lines around the world and many projects that apply the LRT systems in Korea are being proceeded and scheduled. LRT system is operated under the electrical circumstance of high voltage and large current and passengers are exposed in those electrical circumstance. In this paper, EMI/EMC for low frequency range of K-AGT system is measured and analyzed comparing with the international standard.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.298-302
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• 2016

Currently, logistics are in small quantities and in diverse forms, and the amounts are continuously increasing. Railway logistics however are losing their market share every year mainly due to low operation speed and loading time, which means the trucks are covering the most of the freights. In order to solve these situations, this paper proposed the high speed freight train as working multi-modality with other modes to make effective transshipment. The high speed freight train has maximum operation speed of 300km/h and electric power to run centralized power supply. There are large dual door system, bogie system covering fluctuating load of 15[ton], automatic loading device, ULD(unit load device) bed and ULD locking system in this freight rolling stock. We calculated the performance of powering and braking capacity for this train and proposed how many vehicles are composed of train set. The results in this paper can help to make a decision to define the technical specification of High-speed freight train for the efficiency of rail freight service.