• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.203-203
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• 2000

VDS(Versatile Driving Simulator) 시스템을 이용하여 방전유지전압펄스의 휴지기 변화에 따른 공간전하의 거동과 벽전하, 벽전압 및 효율 특성을 연구하였다. 이때 휴지기 변화에 따른 실험을 위하여 방전유지전압의 진동수 및 duty ratio를 변화시켰고, 사용된 테스트 패널은 전극폭 260um, 전극간격 100um, 격벽높이 120um, 기압은 400Torr로 Ne-Xe(4%) 기체를 사용하였다. 이 결과로부터 방전유지전압펄스의 휴지기 변화에 따른 벽전하, 벽전압 및 효율 측정을 통하여 최적의 방전유지전압펄스의 조건을 결정할 수 있으며, 이는 AC PDP의 효율 향상에 기여할 것으로 판단되어 진다.

• Journal of ILASS-Korea
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• v.25 no.1
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• pp.27-33
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• 2020

NOx, PN and CO emissions from diesel trucks make up a significant portion of domestic air pollutant emissions. Therefore, test vehicles with various emission standards and driving modes were selected to evaluate the emission characteristics of regulated pollutants (NOx, PN, CO) in medium-duty trucks. As a result of test, all test vehicles were satisfied with Euro 5 or 6 regulation. NOx emissions of Euro 6 vehicles with after-treatment of LNT + DPF were lower than those of Euro 5 vehicles with DPF. In WLTC mode, all vehicles have high NOx emissions at section of extra high speeds, which are determined by increased fuel consumption and high combustion temperatures. CO and PN emissions from all vehicles were found to be low at section of low speeds. Also, The NO₂/NOx ratio was analyzed at 7-23% in each mode, and the NO₂/NOx ratio increased as the average vehicle speed increased. In NIER 9 mode, the CO, HC, and PN emissions were higher under cold conditions of engine than hot conditions of engine. In addition, vehicles with after-treatment system of LNT have similar NOx emissions level in this study.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.65-68
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• 2000

We design a new driving system of 5" true color FED using current controlled PWM method. Further more, we successfully developed a 5" FED panel, which resolution is 320$\times$240(Color). When we design a 5" FED driving circuit, FED tips are modeled as R-C for circuit simulator of FED driving circuit. In Video data processing, parallel R, G, B input signals is processed independently, so duty ratio increase and no noise, high quality performance is achieved in display of 5" FED. The luminance is about 100cd/$m^2$, the anode power consumption Is 2.1W and total power of the driving system is 21.54W

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.5
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• pp.506-517
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• 2012

Electronic Toll Collection System (ETCS), so called "Hi-Pass" in Korea, has improved traffic flow at toll gate of highways. It is known that the improvement of traffic flow should reduce air pollutants and $CO_2$ from vehicles. In this study, real driving emission of a light duty truck with Portable Emission Measurement System(PEMS) has been measured to evaluate the emission reduction effect due to ETCS. The correlations between driving variables and emissions have been analyzed to verify its effect on traffic flow improvement and emission reduction at toll gate. We considered average vehicle speed, Relative Positive Acceleration (RPA), and the distance of queue as driving variables. Compared to passing Manual Toll Collection System (MTCS) lane without queue, ETCS was able to reduce 38.7% of $NO_x$, 21.6% of soot, and 27.7% of $CO_2$. The results showed that the higher the average vehicle speed, the lower RPA and no queue in ETCS contributed to the emission reductions. Linear equation models with RPA and queue have been established by the multiple linear regression method. The linear models resulted in the higher coefficient of determination than those with only average vehicle speed used for establishing vehicle emission factors.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.287-296
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• 2017

Although emission regulations have been gradually strengthened in the past decade, the road transport section remains the most important source of NOx emission in air pollution. One reason is that there has been an increase in the proportion of diesel vehicles and in the volume of traffic. In addition, the certification procedure for standard emission limit does not sufficiently reflect real traffic condition and various driving patterns. Therefore, the European Commission(EC) has recently come up with the RDE-LDV(Real driving emissions-light duty vehicle) regulations, and the Ministry of Environment in Korea has been conducting research on evaluating RDE-LDV with PEMS(Portable Emission Measurement Systems). According to the trip requirements of the 2nd RDE package announced by the EC, the objectives of the present study include the development of Korean RDE routes to reflect domestic traffic and road conditions. Based on the results, both RDE routes are in correct compliance with RDE-LDV regulations, including trip requirements and trip dynamics. KOR-NIER Route 1, in particular, has a higher driving load in rural driving with regard to excessive gradient of elevation compared to KOR-NIER Route 2, including relatively plane rural driving.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.123-128
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• 2021

For accurate speed and current control in industrial applications, SRM (Switched Reluctance Motor) is very important to synchronize the stator phase excitation and rotor position in the drive due to its nature. In general, position sensors such as encoder and resolver are used to generate rotational force by exciting the stator winding according to the rotor position and to control the motor by using speed and position information. However, for these sensors, 1) the cost of the sensors is quite large in terms of price, so the proportion of the motor system to the total system cost is high. 2) In terms of mechanical, position sensors such as encoders and resolvers are attached to the stator to increase the size and weight. In conclusion, in order to drive the SRM, control based on the rotor position information should be basically performed, and it is important to design the SRM driving system according to the environment in consideration of the application field. Therefore, in this paper, we intend to study the driving and control characteristics of SRM through variable switching duty control by designing a low-cost analog driving device, deviating from the general control system using the conventional encoder and resolver.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.165-173
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• 2014

The method of emission inspection for Heavy-duty diesel vehicles has been engine speed type Lug-down 3mode. This method could bring damage to decrepit vehicles under high speed and high load condition and it could not apply the driving pattern on the road. For these reasons, this study has started to create new emission inspection which is appropriate for Korea's road infrastructure. KD 147 would be applied to light-duty diesel vehicles from july 2010 after model operations. Therefore, this study has investigated new emission inspection system for heavy-duty diesel vehicles, except for light-duty diesel vehicles. In consideration of domestic conditions to meet the new load test method in this study, the Lug-down3 mode vehicle speed method was developed for the first time in korea.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.30-34
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• 2000

This study minimized the address pulse width for plasma display by analysis of address discharge condition for high speed driving using the ADS driving scheme. As a result, addressing pulse width of 1$mutextrm{s}$ has been realized and luminance of 560cd/$m^2$ can be obtained from the area of 256X160 pixels. And a new AWD scheme is proposed. We accomplished 9.1-inch-diagonal color image with the scan timing of HDTV class PDP, display duty 96.8%.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1402-1408
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• 2015

A MOSFET's gate driver based on magnetic coupling is investigated. The gate driver can meet the demands in applications for wide range of duty cycles and high frequency. Fully galvanic isolation can be realized, and no auxiliary supply is needed. The driver is insensitive to the leakage inductor of the isolated transformer. No gate resistor is needed to damp the oscillation, and thus the peak output current of the gate driver can be improved. Design of the driving transformer can also be made more flexible, which helps to improve the isolation voltage between the power stage and the control electronics, and aids to enhance the electromagnetic compatibility. The driver's operation principle is analyzed, and the design method for its key parameters is presented. The performance analysis is validated via experiment. The disadvantages of the traditional magnetic coupling and optical coupling have been conquered through the investigated circuit.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.44-48
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• 2008

This paper describes on studies of the heavy duty engine calibration for better fuel economy based on real driving conditions. Using testbed validated software simulation of the engine and turbocharger system, an alternative turbocharger specification, with potential to improve fuel economy was identified. Secondly, the engine calibration was modified to optimize vehicle fuel economy over a typical customer drive cycle whilst still meeting the steady-state (testbed) emissions legislation. These results were confirmed by field testing of a vehicle equipped with the updated specifications. This study found good agreements between the prediction and the field test on the vehicle fuel economy improvements of the express bus with updated calibration and turbocharger.