• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1255-1258
• /
• 2006

PM OLED has the line-disturbance when eyes can detect the driving line status in the shaking situation. It is closely related with the lighting intensity and the lighting time during the line driving. .In this paper we suggest the frame part method for eliminating lineflash appearance. Frame part is a driving method of PM OLED, which divides one frame into several inner-frame parts to reduce the color interference between closely related pixels and to lessen the lineflash appearance which disturbs viewer to perceive the images. Frame part groups one frame into several inner-frame parts and have inner-frame rate higher than the frame rate. Frame part could be used in most of applications in PM OLED systems to enhance the total performance of screen quality.

• Proceedings of the Korean Reliability Society Conference
• /
• 2011.06a
• /
• pp.79-85
• /
• 2011

LED(Light Emitting Diode) is a powerful device used in applications as diverse as replacements for aviation lighting, automotive lighting as well as in traffic signals. This study is to propose a prediction system based on the degradation model of LED which is determined by combining scale and shape parameter. The degradation model is analysed goodness of fit test using calculated R-square, and is compared with previous models. A LED prediction system using degradation model is developed to automate estimations of degradation parameters and lifetimes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.67-70
• /
• 2002

The electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. but Increasing awareness of electromagnetic compatibility(EMC) issues in lighting application, the problems of interference generation by electrodeless fluorescent lighting system have been highlighted. In this paper, Maxwell 2D finite element analysis program(ansoft) is used to obtain electromagnetic properties associated with the coil and nearby structures. and also evaluated Flux, B, H, by changing the input current.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.431-434
• /
• 2007

Rapid progress has been made in the development of commercially viable Light Emitting Polymer (LEP) materials for display and lighting applications. This presentation will focus on: ${\bullet}$ Degradation studies that have led to the design of new and improved materials ${\bullet}$ Recent lifetime and efficiency results for red, green, blue, and white polymers ${\bullet}$ Challenges of formulating inks that can be used in a production environment

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.1
• /
• pp.41-45
• /
• 2016

The Cs₃Sb photocathode was formed by non-vacuum process technology and successive in-situ photocathode vacuum device fabrication carried out in a process chamber. Performance testing of the device was followed. Light emission from the devices was induced by photoemitted electrons, which were accelerated by an anode electric field that was shielded from the photoemitter surface. The luminescent characteristics of the devices were investigated by measuring the optical parameters as functions of the applied anode voltages. The results showed that this approach could produce a more easily directed and controlled stream of light. These features make these devices suitable for a variety of planar lighting applications.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.11-14
• /
• 2004

In this paper we report on development of our original mercury-less fluorescent lamps for general lighting. These new-type lamps have multi-pairs of electrodes to maintain multi-discharge paths and to keep positive column diffused state. The omission characteristics oft the lamps were investigated. These discharge lamps were operated by pulsed discharge. By using multi-pairs of electrodes for xenon pulsed discharge fluorescent lamps, higher intensity of luminance was obtained than the conventional type of lamps using single pair of electrodes. Recently this type of lamp achieved over $9000\;cd/m^2$ and 50 lm/W.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.6 no.1
• /
• pp.8-15
• /
• 2011

This paper presents an effective method for detecting vehicles in front of the camera-assisted car during nighttime driving. The proposed method detects vehicles based on detecting vehicle headlights and taillights using techniques of image segmentation and clustering. First, in order to effectively extract spotlight of interest, a pre-signal-processing process based on camera lens filter and labeling method is applied on road-scene images. Second, to spatial clustering vehicle of detecting lamps, a grouping process use light tracking method and locating vehicle lighting patterns. For simulation, we are implemented through Da-vinci 7437 DSP board with visible light mono-camera and tested it in urban and rural roads. Through the test, classification performances are above 89% of precision rate and 94% of recall rate evaluated on real-time environment.

• Journal of Power Electronics
• /
• v.19 no.1
• /
• pp.1-10
• /
• 2019

Current imbalance is the main factor affecting the lifespan of light-emitting diode (LED) lighting systems and is generally solved by active or passive approaches. Given many new lighting applications, independent control is particularly important in achieving different levels of luminance. Existing passive and active approaches have their own limitations in current sharing and independent control, which bring new challenges to the design of LED drivers. In this work, a multichannel resonant converter based on switched-capacitor control (SCC) is proposed for solving this challenge. In the resonant network of the upper and lower half-bridges, SCC is used instead of fixed capacitance. Then, the individual current of the LED array is obtained through regulation of the effective capacitance of the SCC under a fixed switching frequency. In this manner, the complexity of the control unit of the circuit and the precision of the multichannel outputs are further improved. Finally, the superior performance of the proposed LED driver is verified by simulations and a 4-channel experimental prototype with a rated output power of 20 W.

• Journal of Ocean Engineering and Technology
• /
• v.35 no.4
• /
• pp.305-312
• /
• 2021

There is a gradual increase in the need for energy charging in marine environments because of energy limitations experienced by electric ships and marine robots. Buoys are considered potential energy charging systems, but there are several challenges, which include the need to maintain a fixed position and avoid hazards, dock with ships and robots in order to charge them, be robust to actions by birds, ships, and robots. To solve these problems, this study proposes a smart buoy robot that has multiple thrusters, multiple docking and charging parts, a bird spike, a radar reflector, a light, a camera, and an anchor, and its mechanism is developed. To verify the performance of the smart buoy robot, the position control under disturbance due to wave currents and functional tests such as docking, charging, lighting, and anchoring are performed. Experimental results show that the smart buoy robot can operate under disturbances and is functionally effective. Therefore, the smart buoy robot is suitable as an energy charging system and has potential in realistic applications.

• Journal of information and communication convergence engineering
• /
• v.21 no.3
• /
• pp.216-224
• /
• 2023

Smart lighting systems have become increasingly popular in several public sectors because of trends toward urbanization and intelligent technologies. In this study, we designed and implemented a web application platform to explore and monitor data acquired from lighting devices at Thammasat University (Rangsit Campus, Thailand). The platform provides a convenient interface for administrative and operative staff to monitor, control, and collect data from sensors installed on campus in real time for creating geographically specific big data. Platform development focuses on both back- and front-end applications to allow a seamless process for recording and displaying data from interconnected devices. Responsible persons can interact with devices and acquire data effortlessly, minimizing workforce and human error. The collected data were analyzed using an exploratory data analysis process. Missing data behavior caused by system outages was also investigated.