A solar flare was observed on 1997 April 7 with the Soft X-ray Telescope (SXT) on Yohkoh. The flare was associated with a “halo” coronal mass ejection (CME). The flaring region showed areas of reduced soft X-ray (SXR) brightness—“dimmings”—that developed prior to the CME observed in white light and persisted for several hours following the CME. The most prominent dimming regions were located ne...

 The employ of the fluorescent lamps without electrodes (electrodeless) have been increasing, because of their features such as lifetime and lumen efficiency, when compared to conventional fluorescent and high pressure sodium (HPS) lamps. This paper presents a luminous flux variation strategy using a Single Ended Primary Inductance Converter (SEPIC) for feeding of electrodeless fluorescent lam...

Most commercial spaces have enough daylight next to windows to eliminate the need for electric lighting. Daylight harvesting systems automatically dim or switch electric lights depending on daylight availability, offering significant energy savings. Most important they offer significant peak demand reduction, since peak demand usually occurs during the highest levels of daylight availability. D...

In this paper, light-emitting-diode (LED) backlight driving circuits and dimming method for medium-sized and large liquid crystal displays (LCDs) are proposed. The double loop control method, the intelligent-phase-shifted PWM dimming method, the fast-switching current regulator, and the current matching techniques are proposed to improve not only the current regulation characteristics and the p...

An intelligent light emitting diode (LED) dimming system is designed and implemented for energy-saving lighting systems. An LED light bulb is powered by an LED driver controlled by a microcontroller using pulse width modulation (PWM) signals. By changing the duty cycle of the PWM signals, the LED driver generates a driving current of up to 1,000 mA. The current consumption by the LED light bulb...

Light-emitting diode (LED) road lighting has been widely implemented in recent years, but few studies have evaluated its performance after installation. This study investigated whether LED road lighting complies with minimum regulations in terms of traffic safety and whether improvements for energy efficiency are possible. Average road surface luminance (L), overall luminance uniformity (Uo), l...

Dimming is an important feature of an indoor lighting system where the illumination level can be controlled by the user. Therefore, integrating a visible light communication (VLC) system with an illumination system poses some challenges. One of the main issues is that the light unit should be “ON” all the time to ensure continuous communication. To ensure acceptance and adoption of VLC systems,...

Visible light communication (VLC) could provide short-range optical wireless communication together with illumination using LED lighting. However, conventional forward error correction (FEC) codes for reliable communication do not have the features for dimming support and flicker mitigation which are required in VLC for the main functionality of lighting. Therefore, auxiliary coding techniques ...