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Author Sweater-Hickcox, K.; Narendran, N.; Bullough, J.; Freyssinier, J. url  doi
openurl 
  Title Effect of different coloured luminous surrounds on LED discomfort glare perception Type Journal Article
  Year 2013 Publication Lighting Research and Technology Abbreviated Journal Lighting Research and Technology  
  Volume 45 Issue 4 Pages 464-475  
  Keywords perception; subjective; LED; LED lighting; spectral power distribution; SPD  
  Abstract Recently, there has been increased interest in energy-efficient lighting as energy resources become higher in demand. Anecdotal evidence suggests that certain populations believe light-emitting diodes (LED) produce more glare than traditional technologies. This may be due to a number of factors such as spectral power distribution (SPD), source luminance, or beam intensity distribution. A study was conducted to assess the effect of different SPDs on the perception of discomfort glare from an LED source. For the range of conditions evaluated, the presence of any luminous surround significantly reduced the perception of discomfort glare from the LED array. The blue luminous surround reduced discomfort glare perception significantly less than the white or the yellow luminous surrounds. The implications for solid-state lighting systems are discussed.  
  Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1477-1535 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 338  
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Author Kostic, A.; Kremic, M.; Djokic, L.; Kostic, M. url  doi
openurl 
  Title Light-emitting diodes in street and roadway lighting – a case study involving mesopic effects Type Journal Article
  Year 2013 Publication Lighting Research and Technology Abbreviated Journal Lighting Research and Technology  
  Volume 45 Issue 2 Pages 217-229  
  Keywords LED; LED lighting; mesopic; street lighting; outdoor lighting; roadway lighting  
  Abstract The paper considers the justification for the application of light-emitting diode (LED) technology to urban lighting. The results suggest that LEDs are convenient for architectural lighting and deserve to be considered for use in ambient lighting. The recently developed Commission Internationale de l’Eclairage (CIE) mesopic system enabled the inclusion of mesopic effects into a comprehensive techno-economic analysis, which dealt with efficiency, maintenance and financial aspects of the use of LEDs in street and roadway lighting. It is concluded that the average energy savings when using LED instead of high-pressure sodium (HPS) luminaires amount to 19–26% for single-sided, staggered and opposite layouts, although they are frequently negligible if mesopic effects are not included. The total costs of the LED lighting solutions, even including mesopic effects, are 1.36 to 6.44 times higher than those of the comparable HPS lighting solutions. Therefore, LEDs are questionable for street and roadway lighting.  
  Address Faculty of Architecture, University of Belgrade, Belgrade, Serbia  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1477-1535 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 339  
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Author Vetter, C.; Juda, M.; Lang, D.; Wojtysiak, A.; Roenneberg, T. url  openurl
  Title Blue-enriched office light competes with natural light as a zeitgeber Type Journal Article
  Year 2011 Publication Scandinavian Journal of Work, Environment & Health Abbreviated Journal Scand J Work Environ Health  
  Volume 37 Issue 5 Pages 437-445  
  Keywords *Circadian Rhythm; *Color; Humans; *Lighting; *Occupational Health; Sleep; Wakefulness; blue light; circadian disruption; Circadian rhythm; sleep  
  Abstract OBJECTIVES: Circadian regulation of human physiology and behavior (eg, body temperature or sleep-timing), depends on the “zeitgeber” light that synchronizes them to the 24-hour day. This study investigated the effect of changing light temperature at the workplace from 4000 Kelvin (K) to 8000 K on sleep-wake and activity-rest behavior. METHODS: An experimental group (N=27) that experienced the light change was compared with a non-intervention group (N=27) that remained in the 4000 K environment throughout the 5-week study period (14 January to 17 February). Sleep logs and actimetry continuously assessed sleep-wake behavior and activity patterns. RESULTS: Over the study period, the timing of sleep and activity on free days steadily advanced parallel to the seasonal progression of sunrise in the non-intervention group. In contrast, the temporal pattern of sleep and activity in the experimental group remained associated with the constant onset of work. CONCLUSION: The results suggest that artificial blue-enriched light competes with natural light as a zeitgeber. While subjects working under the warmer light (4000 K) appear to entrain (or synchronize) to natural dawn, the subjects who were exposed to blue-enriched (8000 K) light appear to entrain to office hours. The results confirm that light is the dominant zeitgeber for the human clock and that its efficacy depends on spectral composition. The results also indicate that blue-enriched artificial light is a potent zeitgeber that has to be used with diligence.  
  Address Institute for Medical Psychology, Centre of Chronobiology, Ludwig-Maximilians-Universitat, Munich, Germany  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0355-3140 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21246176 Approved no  
  Call Number IDA @ john @ Serial 350  
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Author Lin, Y.; Liu, Y.; Sun, Y.; Zhu, X.; Lai, J.; Heynderickx, I. url  doi
openurl 
  Title Model predicting discomfort glare caused by LED road lights Type Journal Article
  Year 2014 Publication Optics Express Abbreviated Journal Opt. Express  
  Volume 22 Issue 15 Pages 18056  
  Keywords LED; LED lighting; glare; road safety; traffic  
  Abstract To model discomfort glare from LED road lighting, the effect of four key variables on perceived glare was explored. These variables were: the average glare source luminance (Lg), the background luminance (Lb), the solid angle of the glare source from the perspective of the viewer; and the angle between the glare source and the line of sight. Based on these four variables 72 different light conditions were simulated in a scaled experimental set-up. Participants were requested to judge the perceived discomfort glare of these light conditions using the deBoer rating scale. All four variables and some of their interactions had indeed a significant effect on the deBoer rating. Based on these findings, we developed a model, and tested its general applicability in various verification experiments, including laboratory conditions as well as real road conditions. This verification proved the validity of the model with a correlation between measured and predicted values as high as 0.87 and a residual deviation of about 1 unit on the deBoer rating scale. These results filled the gap in estimating discomfort glare of LED road lighting and clarified similarities of and differences in discomfort glare between LED and traditional light sources.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1094-4087 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 351  
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Author Pawson, S.M.; Bader, M.K.-F. url  doi
openurl 
  Title LED lighting increases the ecological impact of light pollution irrespective of color temperature Type Journal Article
  Year 2014 Publication Ecological Applications Abbreviated Journal Ecological Applications  
  Volume 24 Issue 7 Pages 1561-1568  
  Keywords biodiversity; high-pressure sodium lamp; light pollution; spectra; street lighting; urbanization; LED; color temperature; ecology  
  Abstract Recognition of the extent and magnitude of night-time light pollution impacts on natural ecosystems is increasing, with pervasive effects observed in both nocturnal and diurnal species. Municipal and industrial lighting is on the cusp of a step change where energy-efficient lighting technology is driving a shift from “yellow” high-pressure sodium vapor lamps (HPS) to new “white” light-emitting diodes (LEDs). We hypothesized that white LEDs would be more attractive and thus have greater ecological impacts than HPS due to the peak UV-green-blue visual sensitivity of nocturnal invertebrates. Our results support this hypothesis; on average LED light traps captured 48% more insects than were captured with light traps fitted with HPS lamps, and this effect was dependent on air temperature (significant light × air temperature interaction). We found no evidence that manipulating the color temperature of white LEDs would minimize the ecological impacts of the adoption of white LED lights. As such, large-scale adoption of energy-efficient white LED lighting for municipal and industrial use may exacerbate ecological impacts and potentially amplify phytosanitary pest infestations. Our findings highlight the urgent need for collaborative research between ecologists and electrical engineers to ensure that future developments in LED technology minimize their potential ecological effects.  
  Address Scion, P.O. Box 29-237, Fendalton, Christchurch, New Zealand  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Editor  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-0761 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 367  
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