In the field of indoor wireless networks, visible light communications would be contributing a vital role in the future. This paper investigates the performances of data transmissions using visible light based on unipolar orthogonal frequency division multiplexing (OFDM) and discusses possible approach for light dimming. Asymmetrically clipped optical OFDM (ACO-OFDM) is considered as a unipolar...

A new primary side regulation constant voltage (PSR-CV) two-stage solution is proposed in this paper to avoid low frequency current ripple and to maintain high power factor, low cost compared with currently single stage and conventional three-stage solution in analog LED dimming or non-dimming application. PSR-CV is employed in primary side to achieve high power factor, simple circuit combined ...

An adaptive dimming technique controls both LCD panel transmittance and its backlight luminance adequately and locally according to the input TV signal. The technique reduces the power consumption and also improves the picture quality. However, a steep change in backlight luminance distribution due to the application of the technique causes image degradation around the boundary of the segments ...

[1] Summer soil moisture increased significantly from 1958 to the mid 1990s in Ukraine and Russia. This trend cannot be explained by changes in precipitation and temperature alone. To investigate the possible contribution from solar dimming and upward CO2 trends, we conducted experiments with a sophisticated land surface model. We demonstrate, by imposing a downward trend in incoming shortwave ...

A digitally addressable digital dimming ballast has been developed. It conforms to DALI standard requiring very few parts and operates at very low power. Applications include building management or studio lighting where it is desired to control single or groups of lamps for conserving energy, performing lamp maintenance or creating prefect light quality. The design includes the digital dimming ...

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...