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Author Kocifaj, M.
Title Towards a Comprehensive City Emission Function (CCEF) Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal JQSRT
Volume 205 Issue (up) Pages 253-266
Keywords Lighting; Skyglow
Abstract The comprehensive city emission function (CCEF) is developed for a heterogeneous light-emitting or blocking urban environments, embracing any combination of input parameters that characterize linear dimensions in the system (size and distances between buildings or luminaires), properties of light-emitting elements (such as luminous building façades and street lighting), ground reflectance and total uplight-fraction, all of these defined for an arbitrarily sized 2D area. The analytical formula obtained is not restricted to a single model class as it can capture any specific light-emission feature for wide range of cities. The CCEF method is numerically fast in contrast to what can be expected of other probabilistic approaches that rely on repeated random sampling. Hence the present solution has great potential in light-pollution modeling and can be included in larger numerical models. Our theoretical findings promise great progress in light-pollution modeling as this is the first time an analytical solution to city emission function (CEF) has been developed that depends on statistical mean size and height of city buildings, inter-building separation, prevailing heights of light fixtures, lighting density, and other factors such as e.g. luminaire light output and light distribution, including the amount of uplight, and representative city size. The model is validated for sensitivity and specificity pertinent to combinations of input parameters in order to test its behavior under various conditions, including those that can occur in complex urban environments. It is demonstrated that the solution model succeeds in reproducing a light emission peak at some elevated zenith angles and is consistent with reduced rather than enhanced emission in directions nearly parallel to the ground.
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Corporate Author Thesis
Publisher ScienceDirect Place of Publication Editor
Language English Summary Language English Original Title
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1757
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Author Bullough, J.D.
Title Human Factors Impacts of Light-Emitting Diode Airfield Lighting Type Journal Article
Year 2017 Publication Transportation Research Record: Journal of the Transportation Research Board Abbreviated Journal Transportation Research Record: Journal of the Transportation Research Board
Volume 2626 Issue (up) Pages 51-57
Keywords Lighting
Abstract Light-emitting diodes (LEDs) differ from incandescent light sources in several ways that are relevant to energy and maintenance requirements of airfield lighting systems. They have higher luminous efficacy and, when designed properly, have longer useful operating lives; both factors make LEDs attractive candidates for airfield lighting. The photometric, colorimetric, and temporal characteristics of LEDs also differ from those of incandescent light sources, and these can have important implications for the appearance of runway and taxiway lighting systems. The present paper reviews publications summarizing experimental and analytical investigations designed to assess these implications with respect to the following human factors impacts: color identification, brightness and glare, visibility in fog and haze, response to onset of flashing lights, and stroboscopic effects such as the phantom array. Overall, this review of experimental evidence suggests that, in addition to their reduced energy use and maintenance requirements, LED airfield lighting can be advantageous in comparison with incandescent lighting systems used to delineate airport runways and taxiways.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0361-1981 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1758
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Author John D. Bullough
Title Opinion: Will road lighting wither? Type Journal Article
Year 2017 Publication Lighting Research & Technology Abbreviated Journal
Volume 49 Issue (up) Pages 672
Keywords Commentary; Lighting
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1761
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Author S Fotios, J Uttley
Title Illuminance required to detect a pavement obstacle of critical size Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal
Volume 50 Issue (up) Pages 390-404
Keywords Vision; Lighting
Abstract This paper investigates the illuminance needed to detect trip hazards for pedestrians walking after dark. In previous work, it was assumed that the critical obstacle height is 25 mm: further review of accident data and foot clearance data suggests instead that 10 mm is the critical height. Eye tracking records suggest a tendency for obstacles to be detected approximately 3.4 m ahead. Interpretation of obstacle detection data suggests horizontal photopic illuminances of up to 0.9 lux are required for peripheral detection of a 10 mm obstacle 3.4 m ahead, according to the scotopic/photopic ratio of the lighting and the age of the observer.
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1765
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Author Rice Kinder Institute for Urban Research
Title What Happens in the Shadows: Streetlights and How They Relate To Crime Type Journal Article
Year 2017 Publication Abbreviated Journal
Volume Issue (up) Pages
Keywords Crime; Lighting
Abstract After finding in a previous report, “Streetlights in the City: Understanding the Distribution of Houston Streetlights,” that the city of Houston’s more than 173,000 streetlights were not evenly distributed throughout the city, this next report answers the question: do places with more streetlights have lower crime rates?

The findings complicate the common perception that more streetlights lead to fewer crimes. While there was some evidence that a particularly high density of streetlights can provide protective benefits, excluding those extremes provides a much muddier picture, suggesting that crime is a reflection of other neighborhood contexts. As such, cities should be cautious in expecting direct reductions in crime with the introduction of more streetlights.
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Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1804
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