• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.159-163
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• 2016

In this paper, a frequency tunable double band-stop resonator (BSR) with voltage control by varactor diodes is suggested. It makes use of a half-wavelength shunt stub as its conventional basic structure, which is replaced by the distributed LC block. Taking advantage of the nonlinear relationship between the frequency and electrical length of the distributed LC block, a dual-band device can be designed easily. With two varactor diodes, the stop-band of the resonator can be easily tuned by controlling the electrical length of the resonator structure. The measurement results show the tuning ranges of the two operating frequencies to be 1.82 GHz to 2.03 GHz and 2.81 GHz to 3.03 GHz, respectively. The entire size of the resonator is $10mm{\times}11mm$, which is very compact.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.529-538
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• 2017

There has been much interest in optimizing the halting patterns of high-speed trains, for example by introducing more non-stop trains to supply faster train service to the passengers, which could later bring about a discussion about introducing new high speed train service with differentiated price and service. In general, halting patterns can be considered by constructing an efficient line plan, in which all demand should be covered and the total travel time can be reduced as much as possible. In this study, we present a two-step process based on two optimization models. One is to minimize total kilometers of trains to run on each route ; this will be done using a line planning model under the assumption of all-stop patterns. Then, in the next step, the all-stop patterns are optimally decomposed into several halting patterns in order to minimize the total travel time. We applied the two-step process to the latest demand data in order to develop KTX halting patterns as well as to determine the frequency of each line and compare the current line plan with the optimized one.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.228-230
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• 2006

While trains perform a complete precision stopping control at stop point, it is essential to keep better commuters comfort in prompt. Because a train's brake force tends to increase a brake effort in a low speed and a low brake effort, a brake force in motor cars must be increased to keep better passenger comfort, to control the special braking qua1ities and to prevent the impact of the automatic coupler rather than trailer's, Rail cars must have a special braking process for the train stopping control. In the train stop mode, the train stopping control is designed to start at 20km/h. It starts by Dynamic brake blending, and then finally stops by only the friction. If these process are not exactly activated, the train may fail a complete precision stop. In this report, it studied the electric and friction brake processing during the precious stopping control. To achieve exact test results, the speed reference has to be reduced the calculated difference. In the precision stopping control. the ways of the keeping brake force in motor car was analyzed and some solutions of controling air pressure was brought up by means of direct test in main line, This study was based on line 5 in Seoul Metropolitan subway.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.3
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• pp.140-148
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• 2012

Aeronautical lights, which are internationally standardized sequence of colors and placements, are aeronautic safety devices that provide visual information to pilots by continuously adjusting their light intensity to appropriate level. In this paper, we consider the development testing for in pavement LED aeronautical light system such as taxiway centerline, stop line and temporary stop line. The test results of LED sourced lights have shown a drastic improvement in power consumption levels and cost efficiency compared to their halogen sourced counterparts The LED light used only 42.7% as much power as their halogen sourced counterparts. Taking installation costs into account, LED will cost only 58% of its halogen counterparts. These results suggest that developing the LED sourced aeronautical light would result in globally competitive products thar guarantees satisfaction to their consumers, and that both cost effective and energy efficient.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1798-1803
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• 2003

In this work the dynamic heat transfer occurring in a cable penetration fire stop system built in the firewall of nuclear power plants is three-dimensionally investigated to develop a test-simulator that can be used to verify effectiveness of the sealants. The dynamic heat transfer can be described by a partial differential equation (PDE) and its initial and boundary conditions. For the shake of simplicity PDE is divided into two parts; one corresponding to the heat transfer in the axial direction and the other corresponding to the heat transfer on the vertical layers. Two numerical methods, SOR (Sequential Over-Relaxation) and FEM (Finite Element Method), are implemented to solve these equations respectively. The axial line is discretized, and SOR is applied. Similarly, all the layers are separated into finite elements, where the time and spatial functions are assumed to be of orthogonal collocation state at each element. The heat fluxes on the layers are calculated by FEM. It is shown that the penetration cable influences the temperature distribution of the fire stop system very significantly. The simulation results are shown in the three-dimensional graphics for the understanding of the transient temperature distribution in the fire stop system.

• Journal of the Korea Society of Computer and Information
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• v.21 no.11
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• pp.59-64
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• 2016

In this paper, we design and implement an Application based on android platform, which can control arduino Prime Smart Car using Bluetooth communication. This Application consist of Bluetooth communication module, manual mode module, and line-tracer mode module. In the Bluetooth communication module, it checks the on/off status of Smartphone Bluetooth. If Bluetooth status is off, it activates Bluetooth, selects the corresponding device from Bluetooth device list, and connects with a pair. In order to reduce coding time, we implements Bluetooth communication using inherited class from android Bluetooth package. In the manual mode module, it implements six direction moving button and stop button, which can control arduino Prime Smart Car. In the line-tracer mode module, it implements Prime Smart Car with self-driving function using TCRT5000 sensor. And moving button and stop button is disabled.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.544-552
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• 2010

In this paper, a new method to enhance the stop bandwidth of the compact microstrip bandstop filter based on split ring resonator(SRR) was proposed. To achieve wide stop bandwidth, we incorporated the SRR within the circular etched pattern of the defected ground structure(DGS). By incorporating the SRR within the circular etched pattern, a high magnetic coupling between SRR and signal line can be achieved. The high magnetic coupling enables the proposed structure to achieve a wide stop bandwidth. To verify the feasibility of the proposed structure, the proposed bandstop filter was compared with conventional bandstop filter employing SRRs which have been etched at both sides of the signal line. Simulation and experimental results show that the proposed structure provides an enhanced stop bandwidth compared with the conventional structure.

• Journal of Korean Society of Transportation
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• v.6 no.1
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• pp.55-64
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• 1988

Prior to using any computer model, the program-embedded palameters showing significant differences from real world should be calibrated. This is especially true when the model is expected to be used fro various roadway and traffic condition. The calibration of TRANSYT model was conducted for the parameters of start-up delay, and lag, stop penalty(K), platoon dispersion factor, and saturation flow rate. The values of the parameters were obtained by theoretical methods from actual field measurements for discharging and arrival pattern. The sites elected for the study was an intersection of Dongil-Ro and Hwarang-Ro, and a 334 meter downstrean section from the intersection stop line on westbound Hwarang-Ro. The study results showed that the start-up delay was 2.6 sec, end lag was 1.0 sec, saturation flow rate was 2287 pcphgpl, platoon dispersion factor was 0.2-03, and stop penalty(K) was 32. However, since these parameters re apt to depend on traffic and roadway condition, it is doubtful whether the obtained values will be applicable to the area-wide situation other than this particular site.

• ETRI Journal
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• v.30 no.5
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• pp.735-737
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• 2008

We propose a novel spatial multi-band-stop filter using modified multiple loop array elements to block electromagnetic waves or signals of mobile phones in public facilities. It operates at the following frequency bands: Korean cellular (824 MHz to 894 MHz), Personal Communication Service (PCS) (1.75 GHz to 1.87 GHz), and IMT-2000 (1.92 GHz to 2.17 GHz). Two frequency selective surfaces with modified multiple-loop elements are printed on the top and bottom of a pair-glass pane, which is a pair of glass panes with an air gap between them. A modified multiple-loop element with a meander line is used to make the size of the filter compact. The simulated and measured results show good agreement, which confirms the usefulness of the proposed tri-band spatial filter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.61-67
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• 2018

Automatic Train Stop (ATS) is a device that automatically stops or decelerates a train when the train exceeds the permitted speed limits or violates the signal regulations. The railway signaling system has been evolved to an automatic train control system (ATC), and is being developed into Distance-to-Go and Communication Based on Train Control (CBTC). In spite of that, the ATS system is currently being operated in Seoul Metro (line 1 and 2) and most of railway lines in Korea as well as overseas. In this study, we presents the technical methodology to prevent human errors in order to secure the safety in operation of the ATS system.