• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.45-52
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• 2009

The off-state impedance of LED signal head is greater than that of a traditional bulb signal head, and the traffic controller has inherent off-state output leakage current. These two characteristics make the field trouble and reduce signal safety when the LED signal head is installed with traffic controller. In this Paper, a complement method of the LED signal head and traffic controller local standard (220vac line voltage) for improving signal safety is suggested. The point of designed complement method is to reduce the output leakage current of the traffic controller under 3mA, to increase the voltage feedback threshold to $70{\pm}5V$, and to make LED signal head maintain off-state in 0-95vac with 10Kohm maximum impedance.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.643-648
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• 2011

In this study, SMPS driven LED traffic signal light for Large-scale traffic such as railroad and airport was designed and its electrical and EMI characteristics were measured. The output current of the LED module driven by SMPS was 1.67A for AC and DC input voltage over 10V. The conducted emission measured over 0.15~30MHz frequency range was lower than the allowed quasi-peak and average level, and the radiated noise measured over 30~1000MHz frequency range showed $23.96dB{\mu}V/m$ at 59.96MHz.

• Journal of Applied Reliability
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• v.10 no.4
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• pp.265-278
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• 2010

Module of the LED traffic signal is the core component for the care of driver and walker. Also it is important one to control the traffic. If it is against the criteria of brightness, it is the source of the people's death and traffic congestion. Therefore, it is a list of articles desired the security of stability. However, there is not the analysis of failure and not preserve the uniformity of quality. Therefore, it is necessary to establish the criteria of appreciation for the module of the LED traffic signal to analysis the data of failure. In this paper, we investigate the performance test, environment field test and test of reliability appreciation to improve the reliability. We also set up the criteria of success decision using the real measurement data.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.20-24
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• 2006

In this paper we investigated the method of examining the accelerated life test on LED traffic signal module by the temperature. The longevity presumption of the LED type signal light by a general heat cycle test used and executed cycle when it was done to longevity by the heat cycle test number and the acceleration factor of a real system requirements of this heat cycle test. Therefore, it reports on the introduction of the acceleration type from which the LED traffic signal module is done here to clarify the above-mentioned acceleration factor with the object and the acceleration factor is requested the test atmosphere actually in the system requirements.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.41-48
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• 2017

It is necessary to develop an LED traffic light lens having a snow removal function capable of clearly providing a traffic signal to the driver even when a traffic light is blurred due to heavy snow and wind in the winter season. This study is focused on the research and development of the traffic light lens in the process of developing the LED traffic light with the snow removal function. In the developed traffic light lens, instead of attaching the film heater, the coated nichrome wire was wound into a coil shape and inserted directly into the groove in the lens. The developed heater system facilitates the insertion of the heating wire with high elasticity into a curved lens and can provide a sufficient heat without deformation of the PC lens. The proposed traffic lights were tested in various external environments and the test results showed that complete snow removal is possible without tunnel effect.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.171-174
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• 2004

Concerning Korean energy consumption, 20% of the total electrical energy (96% is now exported) is consumed in lighting area. Accordingly, it is one of the most important governmental policies to efficiently utilize electricity due to development and application of high-efficiency lighting equipment. In Korea, widely-built traffic signals employ an incandescent and are of 100W/300 mm, and 280,080set/801,932lamps have been installed and operated by 1999. Of them, 58%(161,181set), 25%(69,655set) and 18%(49,244set) correspond to traffic signals, pedestrian signals and other supplementary signals respectively. It was estimated that electrical energy consumed 28MW instantaneously, 245GWH annually. On the other hand, the LED traffic signal is expected to be a future traffic signal since if traffic signals are replaced by LEDs, energy saving effect of 85% and drop of 75% in maintenance fee will be obtained. In this paper, the performance and characteristics of many LED traffic signals made in Korea are summarized in order to reform Korean standard of LED traffic signals.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.183-188
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• 2005

Instead of the incandescent lamps the LED lamps have been used on the traffic signal lamp with the advantages of small loss, no lens and long life. In this paper, we have compared three kinds of the LED controller structures and showed the LED array decision methods. We studied the temperature characteristics on LED and the temperature compensation network. The experimental results showed that the electrical characteristics of three kinds of the LED controller structures were different each other. We concluded that the temperature compensation is the important technique, the best compensation network has the ${\pm}10%$ variation for the luminous intensity.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.11a
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• pp.153-158
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• 2001

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.885-889
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• 2006

Metro Subway System is widely known as the leader of public transportation in a metropolitan area. The signal interlocking is one of the most important organs that plays a major role in the system. By improving the quality of signal lights on the traffic system and keeping its maintenance on a high level will not only repair the current state, but it will also let the LED type signal semi-permanent. The device, which underwent a process of fine manufacture establishment and a close examination, obtained a patented article (2004, as a new device). Utilizing the equipment with cautious preservation on the system will enhance the current state of the signal device. Especially, the test for improvement and development based upon the technique that decreases the frequency of defect produced will further precipitate its efficiency. With authorization of imposing the LED lights on production, installment, and investigation of the system, the newly made equipment will bring improvement to the signal technology and to the industry at largest extent.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.139-140
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• 2010

This paper presents an indoor prototype for wireless digital signal transmission using Visible Light Communications (VLC) in which high power Light Emitting Diode (LED) is used. Using low cost and off-the-shelf components, the transmitter module is constructed using an AVR Atmega128 microcontroller and commercial white beam LEDs. Modulating the light intensity of the LED enables digital signals to be transmitted across the optical link. The receiver module employs a high speed PIN photodetector for optical signal detection and a recovery circuit for optical-electro signal conversion. By sending digitalized data via VLC technology, many applications can be realized in the areas of consumer advertising, traffic safety information and disaster control.