toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Li, Fusheng; Chen, Yuming; Liu, Yang; Chen, Dahua url  doi
openurl 
  Title Comparative in Situ Study of LEDs and HPS in Road Lighting Type Journal Article
  Year 2012 Publication LEUKOS: The Journal of the Illuminating Engineering Society of North America Abbreviated Journal Leukos  
  Volume 8 Issue 3 Pages 205-214  
  Keywords Roadway lighting, visibility, LED, high-pressure sodium; LED lighting; HPS, STV, achromatic target, colored target  
  Abstract The effect of spectrum on the visibility of roadway lighting targets was investigated. The experiment focused on the relation between average visibility ratings and small target visibility (STV) under installations that employed LED and HPS light sources. Achromatic targets were more visible under LEDs illumination conditions than under HPS illumination conditions. The results also suggest that the visibility of colored objects on the road was better under LEDs illumination conditions in comparison to HPS. The results cannot be generalized to all LED light sources, but are likely indicative of LEDs with similar spectral power distributions (SPDs). Relative visibility under source types with different SPDs, and which provide different luminance distributions, should merit consideration when selecting a light source for roadway lighting.  
  Address Department of Illuminating Engineering & Light Sources, School of Information Science and Engineering, Fudan University, China  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (up) Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 337  
Permanent link to this record
 

 
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 Editor  
  Language (up) 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  
Permanent link to this record
 

 
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 Editor  
  Language (up) 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  
Permanent link to this record
 

 
Author Luo, Wei (ed) pdf  url
openurl 
  Title Outdoor lighting – Mesopic photometry, adaptation conditions and user preferences in pedestrian way lighting Type Book Whole
  Year 2014 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords  
  Abstract The starting point of this work is to review the current recommendations and criteria of road and pedestrian way lighting. At present, the emphasis of traffic safety, the increasing energy costs, and improvements in mesopic photometry have led to new discussions about the accuracy of the recommendations for road lighting. Sufficient road lighting is generally based on the lighting requirements given in different lighting classes.



For road lighting, the value of 2 cd/m2 is recommended as the minimum average road surface luminance for the highest lighting class in the CIE and CEN publications. The basis of the average road surface luminance for the lower lighting classes is unknown and lacks experimental works. Moreover, the experimental set-ups of the studies conducted in the 1930s and 1950s do not meet the conditions of motor traffic lighting nowadays. They also have deficiencies in the number and age distributions of the subjects. The values of the average horizontal illuminances of the pedestrian way lighting recommendations are based on studies conducted in the 1970s and 1980s. However, no information exists on how the recommended illuminance values are derived for the different lighting classes.

The current recommendations for outdoor lighting are based on photopic photometry, this is daylight visibility conditions. In outdoor lighting, the luminances are in the mesopic range. The CIE recommended system for mesopic photometry should be used in providing recommendations and criteria for both road and pedestrian way lighting. Before implementing mesopic photometry, the adaptation luminance of the road users should be known. This study examined the adaptation conditions of pedestrians based on eye-tracking measurements. A case study in a pedestrian way was conducted in Chongqing of China. The study is related to the currently ongoing task of the CIE JCT-1 Implementation of CIE 191 System for Mesopic Photometry in Outdoor Lighting, which is to investigate adaptation and viewing conditions and define visual adaptation fields in outdoor lighting. The case study consisted of eye-tracking measurements and subjective evaluations of the lighting conditions.



It was found that the eye-fixation areas and locations were around a central area of the road surface in the horizontal level but spread over a wider area in the vertical level. The subjective importance of facial recognition depends on the specific visual tasks at different light levels in a pedestrian way. The results also suggest that further studies using an eye-tracking system could combine eye-fixation data with pupil size and luminance data. This would help in further analysis of visual adaptation fields of the road users.
 
  Address Department of Electrical Engineering and Automation, Aalto University, Finland  
  Corporate Author Thesis Ph.D. thesis  
  Publisher Place of Publication Editor Luo, Wei  
  Language (up) Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 340  
Permanent link to this record
 

 
Author Kayaba, M.; Iwayama, K.; Ogata, H.; Seya, Y.; Tokuyama, K.; Satoh, M. url  doi
openurl 
  Title Drowsiness and low energy metabolism in the following morning induced by nocturnal blue light exposure Type Journal Article
  Year 2013 Publication Sleep Medicine Abbreviated Journal Sleep Medicine  
  Volume 14 Issue Pages e166-e167  
  Keywords blue light; light exposure; light at night; circadian disruption; drowsiness; melatonin; metabolism; sleep  
  Abstract Introduction

Evening light exposure debilitates the circadian rhythm and elicits sleep disturbance. Blue light peak wavelengths, around 460 nm, suppress melatonin secretion via the non-image-forming system. The effects of nocturnal blue light exposure on sleep have been reported to be specific but rather small (Münch, 2008). This study was designed to assess the effect of nocturnal blue light exposure on sleep and energy metabolism until noon the next day.

Materials and methods

Nine healthy male volunteers aged between 21 and 25 participated in this study which had a balanced cross-over design with intrasubject comparisons. After 2 h dark adaptation, the subjects were exposed to blue light or no light for 2 h. The peak wavelength of the blue LED was 465 nm, and the horizontal irradiance of the blue light at the height of eye was at 7.02fÊW/cm2. Sleep was recorded polysomnographically, and energy metabolism was measured with a whole body indirect calorimeter.

Results

There were no significant differences in sleep architecture and energy metabolism during the night. However, dozing (stages 1 and 2) was significantly higher (26.0 < 29.4 vs 6.3 < 8.1 min, P < 0.05), and energy expenditure, O2 consumption, CO2 production and the thermic effect of food (increase in energy expenditure after breakfast) were significantly lower the following morning in the blue light exposure subjects.

Conclusion

Contrary to our expectation, sleep architecture and energy metabolism during sleep were not affected by evening exposure to blue light. It might be due to our milder intervention by which subjects in a sitting position did not gaze at the light source set on the ceiling, while the subjects in previous studies directly received brighter light via custom built goggles (Cajochen, 2005; Münch, 2008) or gazed at a light source under the influence of mydriatic agents to dilate pupils (Brainard, 2001). New findings of the present study were that dozing (stages 1 and 2) was significantly increased, and energy metabolism was significantly lower the following morning in blue light exposed subjects. This suggests that modulation of the circadian rhythm is affected by nocturnal blue light exposure and the effect continues in the following daytime even if the intervention was mild.
 
  Address University of Tsukuba, Graduate School of Comprehensive Human Sciences, Japan  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (up) Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 349  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: