• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.7
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• pp.1-9
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• 2012

In this paper, resistance temperature detector (RTD) integrated into the LED package is proposed in order to solve the temperature dependence of LED's optical properties. To measure the package temperature in real time, the RTD type temperature sensor having excellent accuracy and linearity between temperature change and resistance change was adopted. A stable metallic film is required for long term reliability and stability of the RTD type temperature sensor. Therefore, deposition and annealing condition for the film were determined. Based on the determined condition, the RTD type temperature sensor with the sensitivity of about $1.560{\Omega}/^{\circ}C$ was fabricated inside the LED package. In order to configurate the LED package system keeping the constant brightness regardless of the temperature, additional conversion circuit and control circuit boards were fabricated and added to the fabricated LED package. The proposed system was designed to compensate the light intensity caused by temperature change using the variable duty rate of driving current. As a result, the duty rate of PWM signal which is the output signal of the configurated system was changed with the temperature change, and the duty rate was similarly varied with the target duty rate. Consequently, it was focused the fabricated RTD can be used for compensating the optical properties of LED and the LED package which exhibits constant brightness regardless of the temperature change.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2110-2111
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• 2011

Optimal Driving of Photo-Sensor for Control of a Mixed Environment was realized. The control system was carried out to investigate into the characteristics of Real time control of temperature and humidity at sprouts cutivators. Especially, for led's control for the cultivation of sprouts we have composed a Combined Automatic Control System possible for the control of temperature and humidity at the same time. The applied Photo-Sensor measurement are blue, green, red, white, yellow leds. And we had also designed the Web Programming for the automatic control about sprouts plants.

• Journal of IKEEE
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• v.21 no.4
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• pp.368-374
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• 2017

In this Paper, we developed a low power type LED security light using LED lighting that substitutes a 220[V] commercial power source for a solar cell module instead of a halogen or a sodium lamp. in addition, a PWM type drive control circuit is designed to minimize the heat generation problem and the drive current of the LED drive controller. in developed system, The light efficiency measurement value is 93.6[lm/W], and a high precision temperature sensor is used inside the controller to control the heat generation of the LED lamp. In order to eliminate the high heat generated from the LED lamp, it is designed to disperse quickly into the atmosphere through the metal insertion type heat sink. The heat control range of LED lighting was $50-55[^{\circ}C]$. The luminous flux and the lighting speed of the LED security lamp were 0.5[s], and the beam diffusion angle of the LED lamp was about $110[^{\circ}C]$ by the light distribution curve based on the height of 6[m].

• Science of Emotion and Sensibility
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• v.16 no.2
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• pp.195-206
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• 2013

The main causes of traffic accidents while driving a car is of the driver's visual distraction. In this study, the color sensitivity of the information projected on the windshield were evaluated for HUD (Head Up Display) system which helps the driver's eyes on the road while driving. The driving Information were projected $9^{\circ}$ downward from front sight $0^{\circ}$ under lab's fluorescent lights, LED floorlights and the TV had having 25 [lux] illumination when driving at night environment and 100,000 [lux] of daylight environment. Munsell color hue of the basic five colors (R, Y, G, B, P) and the color of traffic lights YR, W were the color of the seven characters, each character were outlined by White, Gray except for W. Total of 19 experimental stimuli was shown in the environment of day and night driving for asking visibility information of color, fatigue, preferences, and evaluate the degree of interference. The results came out that the bright Y and G color is visibility significantly for daylight. Second, with the outline of the text, the color of the outline works as a background for luminance contrast effects and affects visibility. Third, without the outline, the glass in front of the vehicle acts as the background and the luminance contrast of characters achieve greater brightness and visibility. The luminance contrast between the stimuli and background should be considered for increasing color visibility for driving information which is an important factor for HUD commercialization.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.69-75
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• 2015

Road facilities for safe driving were designed for drivers to distinguish them during day and night, but they cannot play their role when the weather becomes worse. Recently, the road facilities have been designed by using electric and electronic technology so that they can be displayed well at a long distance, but they should be replaced very often due to their frequent breakdown. So, there are many problems in traffic calming and maintenance. In this study, to solve the above problems, semi-permanent LED beacon light was installed in the area where traffic accident are frequent, and monitoring system was developed so that the LED beacon light can be maintenanced by connecting with system. For the above installation and development, system was based on window operating system and it was developed for worker to operate it by using P.C. through connecting with wireless local area network. The result of this study led to analyzing state information on the battery of field-installed LED beacon light in real time, and manegement to effectively by predicting their life cycle.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.3
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• pp.145-150
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• 2014

This paper presents an effective vision based method for LED traffic light detection at the daytime. First, the proposed method calculates horizontal coordinates to set region of interest (ROI) on input sequence images. Second, the proposed uses color segmentation method to extract region of green and red traffic light. Next, to classify traffic light and another noise, shape filter and haar-like feature value are used. Finally, temporal delay filter with weight is applied to remove blinking effect of LED traffic light, and state and weight of traffic light detection are used to classify types of traffic light. For simulations, the proposed method is implemented through Intel Core CPU with 2.80 GHz and 4 GB RAM, and tested on the urban and rural road video. Average detection rate of traffic light is 94.50 % and average recognition rate of traffic type is 90.24 %. Average computing time of the proposed method is 11 ms.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.31-40
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• 2017

The rise of eco-friendly personal electric mobility is a worldwide trend and the first Korean-made IT convergence electric skateboard, Youth Board, is developed to lead the trend. Youth Board is remotely controllable using either Youth Wearable Controller or Youth App through Bluetooth v4.0 communication, can speed up to 25 km/hr, and operating time is approximately 1.5 hr. A LED display located in the front side of Youth Board deck shows three different states to a rider for user convenience: remaining battery SOC, current driving speed, and braking amount. Indoor EMC test results between Youth Board and Youth Wearable Controller and outdoor Youth Board driving test results are analyzed. In particular, driving test results show the maximum current output is about 15% lowered compared to the other competitor electric skateboard and it lessens the power burden of the motor ESC. These results show Youth Board's usefulness as a personal mobility in the sense of small, light, and inexpensive aspects.

• Korean Journal of Optics and Photonics
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• v.24 no.5
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• pp.231-236
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• 2013

We investigated the optical design of a smart headlamp capable of producing various beam patterns through only on/off modulation of light sources. This was implemented by forming a continuous matrix of beams from discontinuous beam patterns by means of a multi-array LED optical system. As one such optical system, the multi-array LED system is a convenient and economical device for implementing beam patterns with the simple on/off modulation of the light sources. A single optical assembly module can be made by combining a multiple-LED array, optical system module, and electronic control with no need for any additional mechanical components. The present optical system was designed to include a secondary lens and a projection lens mounted at the front of each LED in the array to realize accurate lighting patterns as well as the required luminosity at a distance of 25 m in the forward direction. Finally, we identified and analyzed the patterns implemented by the designed optical system that produced satisfactory performance of high beams and adaptive driving beams (ADB).

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1172-1174
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• 2009

Color sequential display is a well know technology. Hower, due to the slow response time of LC,the CSD has not been used in LCD. We have developed a unique LC color display, which can improve LC response time, improve the driving system, improve the gamma drive issue and increase the color gamut to more than NTSC120%.It also can get very low power consumption merit.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.3
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• pp.28-33
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• 2002

Several studies indicated that an independent visual background (IVB) reduced simulator sickness (SS) and balance disturbance associated with exposure to virtual environments (VEs) and motion simulators. A recent study showed that an IVB comprised of an earth-fixed grid was less effective in a complex driving simulator than in a simple VE. Subjects' post-experiment reports indicated that the VE motion "induced" motion of the earth-fixed grid m. This led to the suggestion that an IVB comprised of clouds would be less subject to induced motion and therefore would alleviate nausea more effectively than a grid IVB. Clouds are "natural" and are usually perceived as relatively stable, whereas a grid has no inherent stability. 12 subjects were exposed to complex motion through a simulated environment in a driving simulator under 3 IVB conditions: grid, less clouds, many clouds. They reported less nausea when the many-cloud IVB was used relative to the grid IVB condition. grid IVB condition.