Lighting Quality Evaluations using Images on a High Dynamic Range Display

Limited research comparing participant ratings of luminous environments to ratings of images of those environments indicates that images can be a reasonable surrogate for the real space, particularly on ratings related to aesthetics. However, the realism of such images when presented on computer screens is potentially limited by conventional display technologies that cannot reproduce the full range of luminances in real spaces. In this pilot experiment we used a new, high dynamic range (HDR) computer monitor capable of producing screen luminances and contrasts comparable to those in a real space. Fifty-four participants viewed three images of a conventional office in two display modes: HDR monitor and conventional monitor. Participants rated each image for room appearance, environmental satisfaction and realism. These ratings were also compared to similar ratings made by participants in an earlier experiment (reported in 1998) who occupied the real spaces depicted in the images. Results indicate that computer screen images are perceived in a similar way as real luminous environments. HDR images are perceived differently than images on a conventional monitor: they are rated as brighter and less attractive, as expected. Given their more authentic luminances, HDR images should be perceived as more similar to the real space, but our results neither support nor refute this

Validation of the use of high dynamic range images and displays in lighting research

Bu çalışmanın amacı, Yüksek Dinamik Ölçekli (YDÖ) görüntüleme tekniğinin kullanıldığı YDÖ monitörlerin aydınlatma mühendisliği problemlerinin çözümünde kullanılabileceğini göstermektedir. Bu makalede sunulan ilk deney, YDÖ monitörde görüntülenen YDÖ fotoğrafların, LCD ekranda görüntülenen (tek pozlamadan oluşan) geleneksel fotoğraflardan daha gerçekçi olduğu hipoteziyle tasarlanmıştır. Altı adet hacmin detaylı parıltı ölçümleri noktasal ölçüm yapabilen bir parıltı ölçer ve parıltı kamerası kullanılarak yapıldıktan sonra, bu parıltı değerleri YDÖ ekrana yansıtılmıştır. Deney sonuçları YDÖ fotoğraf tekniği ile üretilen fotoğrafların YDÖ ekrandaki göruntülerinin, LCD ekranda görüntülenen tek pozlamadan oluşan fotoğraflardan daha gerçekçi algılandığını göstermiştir. Çalışmanın ikinci bölümünde, YDÖ görüntüleme tekniğinden faydalanılarak bir açık plan ofisteki aydınlatma kalitesi incelenmiştir. Bu çalışmada, görüntü karakteristikleri (ortalama parıltı, parıltı dağılımı ve doğal ışığı hacme alan pencere büyüklüğü) ile hacmin aydınlatma kalitesi arasındaki bağıntı incelenmiştir. Çalışmanın sonuçları, YDÖ ekranda sergilenen YDÖ fotoğrafların özellikle doğal ışık içeren görüntülerde aydınlatma kalitesi analizi yapmak amacıyla gerçek hacim yerine kullanılabileceğini göstermektedir. Henüz inşa edilmemiş binaların grafik simulasyonlarının, gerçek hacimde sağlanması öngörülen parıltı değerleriyle YDÖ ekranda görüntülenmesi, aydınlatma projesine ilişkin karar aşamasında faydalı olacaktır. YDÖ teknolojisi kullanılarak elde edilen sonuçlar literatürdeki çalışmalarla tutarlı olması, YDÖ teknolojisinin aydınlatma mühendisliği problemlerinin çözümünde kullanılmasına ilişkin güveni arttırmaktadır. Anahtar Kelimeler: Aydınlatma tasarımı, Yüksek Dinamik Ölçekli fotoğraflama tekniği, Yüksek Dinamik Ölçekli monitör, aydınlatma kalitesi, ofis aydınlatması.The main goal of this study is to show that a High Dynamic Range (HDR) display can be used in the study of lighting engineering problems, and as a tool in the lighting design process to enhance communications between lighting designers and their clients. Printed photographs, renderings or images displayed on conventional Cathode-Ray Tube (CRT) or Liquid-Crystal Display (LCD) monitors do not represent the spaces in realistic luminances. Calibrated HDR images contain luminance information from the real space, but current LCD monitors cannot present luminances as high as the luminances encountered in the real world. Therefore, these sources do not provide enough information to make accurate judgements of light and shade in the lighting design process. The HDR display used in this study could display luminances up to 4000 cd/m2 and overcame these problems. This research shows that the HDR method may be used as a surrogate for experiencing a real space to investigate lighting engineering problems both for research and the design process. The first experiment was designed to investigate the hypothesis that HDR images on an HDR screen would be perceived as more realistic than conventional images displayed on conventional LCD displays. Extensive luminance measurements were conducted using a spot luminance meter and a luminance camera to facilitate accurate reproduction of real space luminances of six scenes (corridor, gym, mezzanine, lobby, open-plan office, staircase) on the HDR display. Thirty-nine participants viewed six scenes in three modes: the real scenes (observing real spaces in the building), single exposure photographs of the scenes shown in conventional mode (screen resolution and luminance of HDR display adjusted to that of a conventional LCD display), and the HDR photographs shown in HDR mode (capable of luminances as high as 4000 cd/m2 and 216 distinct luminance levels). Half of the participants visited the real spaces first, and the other half saw the digital images first. For each presentation (real and digital images), participants rated what they saw on four semantic differential scales: dim - bright; non-uniform - uniform; unpleasant - pleasant; glaring - not glaring. Participants then viewed the six digital image pairs again, and recorded whether the HDR or conventional image was more realistic. This experiment demonstrated that HDR images presented on an HDR display are rated as significantly more realistic than conventional computer images. The second experiment demonstrated the use of HDR images as a research tool. The experiment focused on the relationship between scene characteristics (average luminance, luminance variability and view size) and space appearance judgements. Twenty-one scenes were created, each scene being the view from an interior cubicle across one cubicle to the exterior wall. The scenes varied in terms of the cubicle panels, window blind setting, and presence or absence of a neighbour in the adjacent cubicle. Extensive luminance measurements were conducted. Sets of bracketed images were taken for each of the 21 scenes, and then these images were combined into HDR images using the software Photosphere. The calibrated HDR images were shown on an HDR display at realistic luminances to 43 participants. The participants rated each scene on 8 scales. The average ratings for each image were plotted against the average luminance, luminance variability and relative view size for that image. The second experiment of the dissertation supported the hypothesis that as panel height in an open office gets lower, ratings for satisfaction with lighting increase, and ratings for privacy decrease. As the view size increased, ratings for satisfaction with lighting and amount of view increased. Regarding satisfaction with privacy, Hybrid (one fabric and one glass stack-on on the second panel) performed as well as Standing Privacy (two fabric stack-ons on the second panel), and regarding satisfaction with view and satisfaction with lighting, Hybrid performed better than Standing Privacy.The results imply that HDR displays may be successfully deployed in the lighting research projects. Both experiments show that people can respond to HDR images in the same way as they would respond to the real space. The results of both experiments are consistent with what is already known from studies of images and in real spaces, which adds confidence to the use of HDR display. Keywords: Lighting design, High Dynamic Range images, High Dynamic Range display, real space luminance matching, open-plan office lighting, lighting quality.

The genomes of two key bumblebee species with primitive eusocial organization

Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

A model of residential energy end-use in Canada: using conditional demand analysis to suggest policy options for community energy planners

We applied conditional demand analysis (CDA) to estimate the average annual energy use of various electrical and natural gas appliances, and derived energy reductions associated with certain appliance upgrades and behaviours. The raw data came from 9773 Canadian households, and comprised annual electricity and natural gas use, and responses to >600 questions on dwelling and occupant characteristics, appliances, heating and cooling equipment, and associated behaviours. Replacing an old (>10 years) refrigerator with a new one was estimated to save 100 kW h/year; replacing an incandescent lamp with a CFL/LED lamp was estimated to save 20 kW h/year; and upgrading an old central heating system with a new one was estimated to save 2000 kW h/year. This latter effect was similar to that of reducing the number of walls exposed to the outside. Reducing the winter thermostat setpoint during occupied, waking hours was estimated to lower annual energy use by 200 kW h/\ub0C-reduction, and lowering the thermostat setting overnight in winter relative to the setting during waking hours (night-time setback) was estimated to have a similar effect. This information may be used by policy-makers to optimize incentive programs, information campaigns, or other energy use change instruments.Peer reviewed: YesNRC publication: Ye

The effect of utility time-varying pricing and load control strategies on residential summer peak electricity use: A review

Peak demand for electricity in North America is expected to grow, challenging electrical utilities to supply this demand in a cost-effective, reliable manner. Therefore, there is growing interest in strategies to reduce peak demand by eliminating electricity use, or shifting it to non-peak times. This strategy is commonly called "demand response". In households, common strategies are time-varying pricing, which charge more for energy use on peak, or direct load control, which allows utilities to curtail certain loads during high demand periods. We reviewed recent North American studies of these strategies. The data suggest that the most effective strategy is a critical peak price (CPP) program with enabling technology to automatically curtail loads on event days. There is little evidence that this causes substantial hardship for occupants, particularly if they have input into which loads are controlled and how, and have an override option. In such cases, a peak load reduction of at least 30% is a reasonable expectation. It might be possible to attain such load reductions without enabling technology by focusing on household types more likely to respond, and providing them with excellent support. A simple time-of-use (TOU) program can only expect to realise on-peak reductions of 5%.Demand response Load shedding

Effect of daylight saving time on lighting energy use: A literature review

The principal reason for introducing (and extending) daylight saving time (DST) was, and still is, projected energy savings, particularly for electric lighting. This paper presents a literature review concerning the effects of DST on energy use. Simple estimates suggest a reduction in national electricity use of around 0.5%, as a result of residential lighting reduction. Several studies have demonstrated effects of this size based on more complex simulations or on measured data. However, there are just as many studies that suggest no effect, and some studies suggest overall energy penalties, particularly if gasoline consumption is accounted for. There is general consensus that DST does contribute to an evening reduction in peak demand for electricity, though this may be offset by an increase in the morning. Nevertheless, the basic patterns of energy use, and the energy efficiency of buildings and equipment have changed since many of these studies were conducted. Therefore, we recommend that future energy policy decisions regarding changes to DST be preceded by high-quality research based on detailed analysis of prevailing energy use, and behaviours and systems that affect energy use. This would be timely, given the extension to DST underway in North America in 2007.

Lighting Choices page 1

The belief that individual control leads to beneficial behavioural outcomes underlies many recommendations to install individual controls for workplace lighting, temperature, and ventilation in workplaces. The present experiment compared the work performance and satisfaction of 47 office workers who were given choices concerning workplace lighting (CS) with age- and sex-matched partners (PP) who were given no choices but worked under identical lighting. Preferred luminous conditions were recorded for both groups. Satisfaction with lighting and the work environment were high for both groups, and the majority of participants chose lighting conditions consistent with current codes and standards for lighting, including energy use. CS participants had greater perceived control than PP participants, but there were no differences in satisfaction, mood, performance or health. PP participants' lighting choices, recorded at the end of the day-long session, created less VDT glare than CS choices. Although there was no short-term benefit of perceived control over lighting, it appears that experience with workplace conditions could lead to the ability to reduce unpleasant conditions if choices were available

Power savings and occupant satisfaction due to a lighting demand response strategy

NRC publication: Ye