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LEUKOS - The journal of the Illuminating Engineering Society of North America
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The Journal of the Illuminating Engineering Society of North America: Volume 9 | Number 1 | July 2012

Publisher's data


Editorial:

LED Troffers: A Glaring Omission


Articles:

Effects of Automotive Interior Lighting on Driver Vision

Michael J. Flannagan and Joel M. Devonshire

This report includes a brief review of some of the past research on vehicle interior lighting and presents the results of a nighttime field study. Participants were asked to perform two tasks while seated in a stationary experimental car on a closed test road at night: 1) detect pedestrians on the road ahead, and 2) rate the subjective brightness of a reflected veiling light on the windshield. The veiling light was varied in both luminance and color. The results indicated that pedestrian detection was closely related to photopic photometric measures, suggesting that the pedestrian task was influenced primarily by cone photoreceptors. Rating of subjective brightness appeared to show an influence of rod photoreceptors. These results have implications for how the photometry of vehicle interior lighting should be performed in order to best correlate with driver visual performance.

Paradigm in Sustainability and Environmental Design: Lighting Utilization Contributing to Surplus-energy Office Buildings

Mohamad T. Araji, Shaun P. Darragh, and Jeffrey L. Boyer

This paper addresses the lighting design strategies and advanced technologies used in the design of the Masdar Headquarters, an office building that is now under construction in Abu Dhabi and is expected to have 103% net-positive energy use. The work emphasizes design goals centered on human visual needs and investigates lighting conditions related to sustainable and climatically responsive architecture. The optimization of the daylighting design strategies is presented, including a shading trellis with integrated photovoltaic cells, conical courtyards, and the sawtooth facade. The study highlights electric lighting concepts predicated on available daylight and advanced lighting controls that incorporate digital dimming ballasts, programmed and user operable controls, daylight harvesting, and occupancy monitoring. Such lighting components supplemented by other design strategies contribute to the energy-use goals while providing high quality luminous environments designed to meet endusers’ visual needs.

UV Radiation as an Attractor for Insects

Alessandro Barghini and Bruno Augusto Souza De Medeiros

Light pollution due to exterior lighting is a rising concern. While glare, light trespass and general light pollution have been well described, there are few reported studies on the impact of light pollution on insects. By studying insect behavior in relation to artificial lighting, we suggest that control of the UV component of artificial lighting can significantly reduce its attractiveness, offering a strong ability to control the impact on insects. We tested the assumption that the degree of visibility of a lamp to insects can predict its attractiveness by means of experimental collections. We found that the expected lamp’s visibility is indeed related to the extent to which it attracts insects. The number of insects attracted to a lamp, however, is disproportionally affected by the emission of ultraviolet radiation. UV triggers the behavior of approaching lights more or less independently of the amount of UV radiation emitted. Thus, even small amounts of UV should be controlled in order to develop bug-free lamps.

Development of a Numerical Model for the Luminous Intensity Distribution of a Planar Prism LED Luminaire for Applying an Optimization Algorithm

Yu-sin Kim, An-seop Choi, and Jae-weon Jeong

LED lighting is often presented as the lighting technology of the future. Yet there are differences in the luminous intensity distributions between luminaires that employ conventional light sources and those that employ LEDs. The optical engineer faces a new challenge of designing for a spatially extended and nonuniform light source. Consequently, a new approach is needed for the optical design of planar LED luminaires. Luminaire optical design is typically performed using a combination of ray-tracing and trialand- error experimentation with the goal of obtaining a target luminous intensity distribution. The number of iterations can be reduced by utilizing optimization algorithms. This study aimed to develop a numerical model for luminous intensity distribution of planar prism LED luminaires and apply the optimization algorithm for prism angle design. A calculation process for the prism optical design of a planar prism LED luminaire was developed. To assess the accuracy of the numerical model, a comparison was performed between results from the numerical model and Photopia 2.0. This study also illustrates a method of the application of unit prism angle zones for the control of luminous intensity distributions. As a next step, the numerical model could be extended to optimize prism angle for a target luminous intensity distribution.

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