Visible light communication (VLC) using LEDs has attracted significant attention recently for the future secure, license-free and electromagnetic-interference (EMI)-free optical wireless communication. Dimming technique in LED lamp is advantageous for energy efficiency. Color control can be performed in the red-green-blue (RGB) LEDs by using dimming technique. It is highly desirable to employ d...

Dimming system using the wire or wireless communication method is used for the LED light dimming. This system requires a separate communication lines and modem. Such requirements have problems that installation cost increase and compatibility is low. Therefore, these methods are not suitable to apply indoor light. In this paper, we describe the dimming controller to solve problems in convention...

The overall scope of this project funded by the US Department of Energy (DOE) is to recommend means of reducing barriers to the wide spread use of lighting controls for commercial/industrial (C/I) applications using fluorescent systems. It is important to note that this project is focused on load-shed applications and photoelectric dimming where energy savings and energy management are of centr...

We find transient, transit-like dimming events within the K2 time series photometry of the young star RIK-210 in the Upper Scorpius OB association. These dimming events are variable in depth, duration, and morphology. High spatial resolution imaging revealed the star is single, and radial velocity monitoring indicated that the dimming events can not be due to an eclipsing stellar or brown dwarf...

W hen considering alternative approaches to the design of dimmable electronic ballasts for fluorescent lamps, the lamp power regulation method employed is the critical factor. It determines the linearity (i.e., the linear response of the light output with the dimming control input), the smoothness of dimming and, most importantly, the stability of the light output. Both digital and analog appro...

LED PWM dimming application for large scale LED video displays is analyzed. The need for short light pulse duration is outlined. PWM dimming with short driving pulses is investigated experimentally. The LED response time skew introduces the nonlinearity for PWM dimming. For LED response time skew estimation, a method is suggested that has been successfully applied to measure some of today’s mar...

Dimming fluorescent lamps is an attractive feature that provides mood and brightness effects as well as having tremendous energy savings potential. Designing a dimmable electronic ballast, however, is a complicated and challenging task. This paper presents an overview for designing a dimming electronic ballast for a T5 35W lamp. Lamp requirements, dimming control methods, and resonant output st...

A sudden depletion or intensity “dimming” of the X-ray corona sometimes accompanies a solar eruptive flare or coronal mass ejection (CME). We have identified a dimming that occurred just prior to a “halo” CME, observed on 1997 April 7 using the Soft X-ray Telescope (SXT) on Yohkoh. Halo CMEs are prime candidates for “space weather” effects. The dimming occurred in compact regions near a flare o...

Variable pulse position modulation (VPPM) is a new modulation scheme that supports simultaneously illumination with dimming control and communication. In this paper, the transmitter, optical wireless channel, and receiver structure of VPPM were modeled mathematically, and their error performance for examining the communication performance according to dimming level and data rate was analyzed. T...

As modem society has been reshaped rapidly into the multimedia information society, large size of display devices is required. Thin-film-transistor liquidcrystal-displays (TFT-LCDs) are one of the most popular display devices from small to large size. TFT-LCDs need backlight source, because they are not a self luminance device. Backlight for LCDs is becoming more important with growth of the LC...