• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.41-47
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• 2006

This paper presents harmonic evaluation of an IAT(Intra Airport Transit) system in Incheon International Airport. It will be used for electric vehicles with 80[kW] per car produced by Mitsubishi Heavy Industries Ltd, and which is constructed with SIV(Static Inverter), VVVF controller and two induction motor. The vehicles operated in the IAT system can be treated as rapidly changing DC loat and at a feeding substation, 3-phase electric power is transferred to DC 750[V] by rectifier. Since vehicles are changing continuously, the voltages for the load fluctuate in the IAT system, and moreover, the voltage fluctuation generates high-order harmonics. It results the difficulty in maintaining power quality in KEPCO systems' side. The power quality of the IAT system in Incheon International Airport is evaluated using PSCAD/EMTDC simulator in the paper. The THD(Total Harmonic Distortion) of voltages and TDD(Total Demand Distortion) of currents, indices are calculated for the IAT system using the results of PSCAD/EMTDC dynamic simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.160-168
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• 2010

This paper presents the analysis of the current as stray current and supplied current of the substation, on the DC railway power system. In DC railway power supply system, the running rails are usually used as the return conductor(negative-polarity) for traction load current. This condition mainly focuses on economic considerations, since it does not require the installation of an additional return conductor. But, problems of low resistance between the running rails for the return conductor and earth allows a significant part of the return load current to leak into the earth. This current is normally called to as leakage or stary current. This stary currents creates serious problems for any electrified matter in the underground. Therefore, reduction of stray current of the DC railway power supply system is also of direct benefit to the operational and safety aspects of the DC railway systems. In this paper, deal with the analysis of the current distribution on the DC railway power system applied the common grounding system, using SPLIT of CDEGS program.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.723-733
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• 2005

This paper presents a deadlock avoidance method for AGVs in automated container terminals. For a more efficient use of AGV traveling area, we divided the area into small-sized grids not enough to cover a whole AGV. Our deadlock avoidance method controls AGVs by identifying strongly connected components(SCCs) in a graph derived from the paths of AGVs on the grids. Also in this paper we suggest a route selection scheme which selects a route by predicting and comparing travel times of candidate routes by using a regression formula. Simulation experiments have shown that the proposed method can control AGVs for 48 hours without deadlocks and the count of AGV visits per QC is increased by $2\~10$ an hour.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.4
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• pp.87-94
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• 2013

This study estimated the changes in delays and speeds of vehicles in exclusive bus lane and road when the High Occupancy Vehicles(HOV) use the median bus lane. Synchro simulation tool was used to optimize the traffic signal time on the network and VISSIM was applied to simulate various scenarios. Here, drivers behavior parameters in VISSIM was optimized using Simultaneous Perturbation Stochastic Approximation(SPSA) algorithm in order to represent real traffic condition. Based on the simulation results, the delay in Doan daero was decreased when the volume of HOV in current condition runs on the median bus lane, whereas delay in Doan dongro was increased in all scenarios. The changes in bus speed was not sharply decreased for both study sites, even though the number of HOV increased to 10%. Thus, it could be allowed that the HOV use the median bus lane in Doan dongro and Doan daero. Future research tasks include studying about changes in delay when the HOV use the curb bus lane.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.595-601
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• 2017

Due to the electrification of railways, fault at the traction line is increasing year by year. So importance of the fault locator is growing higher. Nevertheless at the field traction line, it is difficult to locate accurate fault point due to various conditions. In this paper railway feeding system current loop equation was simplified and generalized though measured data. And substation, train power data were measured under synchronized condition. Finally catenary impedance was predicted through generalized equation. Also simulation model was designed to figure out the effect of load current for train at same location. Train current was changed from min to max range and catenary impedance was compared at same location. Finally, power measurement was performed in the field at train and substation simultaneously and catenary system impedance was predicted and calculated. Through this method catenary impedance can be measured more easily and continuously compared to the past method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.29-36
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• 2002

Recently, power quality problems in AC high-Speed Railway system have been raised, because heavy train and its higher speed are required in addition to new control system by using the Electronic devices. The installation/operation of the Series Capacitor(SC) has been only a device far voltage drop in power system up to now. However, the sufficient effectiveness of compensating In voltage drop has not been proved yet because of technical limitationf SC, and harmonic resonance is attracting a attention as one of new issues. Several problems are expected such as vocational problems of a traction substation, and overloading caused by a new construction of electric railway and the in transport. Therefore, extension of power feeding the fault in the traction substation should be also considered. So this paper represents the application of TSC-SVC on the electric railway power feeding system as a device of voltage compensation, and the simulations are executed through PSCAD/EMTDC.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.33-41
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• 2022

An important operational goal of a container terminal is to maximize the efficiency of the operation of quay cranes (QCs) that load and/or unload containers onto and from vessels. While the maximization of the efficiency of the QC operation requires minimizing the delay of yard tractors (YT) that transport containers between the storage yard and QCs, the delay is often inevitable because of traffic congestion. In this paper, we propose a method for learning a model that predicts traffic speed in a terminal using only YT operation data, even though the YT traffic is mixed with that of external trucks. Without any information on external truck traffic, we could still make a reasonable traffic forecast because the YT operation data contains information on the YT routes in the near future. The results of simulation experiments showed that the model learned by the proposed method could predict traffic speed with significant accuracy.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.9-15
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• 2010

When designing the size of a heavy maintenance shop for rolling stock, it is required to arrange buildings and facilities in the minimum site so as to improve the maintenance efficiency. However, the fluctuation rate (hereinafter "allowance rate") on which factors such as service and maintenance fluctuation should be applied when estimating the size of the maintenance shop has been used without verification. The objective of the study is to calculate a reasonable allowance rate and to review its appropriateness through the analysis of the facilities layout and process simulation to absorb the above elements into the staying time in the heavy maintenance shop. Since the working time, in this study, is assumed to be average working time, 10~20% was given to the standard deviation of working time in consideration of difference between workers, and possible allowance rate was drawn by analysis of the simulation results. In the future, it is required to optimize the size of the shop by applying appropriate allowance rate through scientific review of such factors as O&M plan, R/S reserve rate, capability of the shop, outsourcing rate, standard work amount, and so on.

• Journal of Korean Society of Transportation
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• v.36 no.1
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• pp.51-65
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• 2018

Intentional aggressive driving (IAD) is defined as a hazardous driving event that the aggressive driver intentionally threatens neighbor drivers with abrupt longitudinal and lateral maneuvering. This study developed a methodology for detecting IAD events based on the analysis of interactions between aggressive driver and normal driver. Three major aggressive events including rear-close following, side-close driving, and sudden deceleration were analyzed to develop the algorithm. Then, driving simulation experiments were conducted using a multi-agent driving simulator to obtain data to be used for the development of the detection algorithm. In order to detect the driver's intention to attack, a relative evaluation index (Erratic Driving Index, EDI) reflecting the driving pattern was derived. The derived IAD event detection algorithm utilizes both the existing absolute detection method and the relative detection method. It is expected that the proposed methodology can be effectively used for detecting IAD events in support of in-vehicle data recorder technology in practice.

• Journal of Korea Game Society
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• v.15 no.5
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• pp.131-142
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• 2015

A self-driving car is an autonomous vehicle capable of fulfilling the main transportation capabilities of a traditional car. It must be capable of sensing its environment and navigating without human input. In this paper, we design the agent that can simulate these self-driving cars and develop a prototype for it. To do this, we analyze the requirements for the self-driving car, and then the agent is designed to be suitable for traditional multi-agent system. The key point of the design is that agents move along the steering forces only. The prototype of the designed agent was implemented by using Unity 3D. From simulation results using the prototype, movements of the agents were very realistic. However, in the case of increasing the number of the agent the performance was seriously degraded, and so the alternatives of the problem were suggested.