Leukos最新文献

{"title":"Lighting System Control Data to Improve Design and Operation: Tunable Lighting System Data from NICU Patient Rooms","authors":"A. Wilkerson, S. Safranek, L. Irvin, Lauri Tredinnick","doi":"10.1080/15502724.2022.2059669","DOIUrl":"https://doi.org/10.1080/15502724.2022.2059669","url":null,"abstract":"ABSTRACT The advancement of LED and controls technology, computing capacity, and software provides new opportunities for researchers and designers to work together to further optimize spaces for occupant benefit. Lighting system control data from five neonatal intensive care unit patient rooms was collected over a 25-week monitoring period and analyzed to better understand occupant response to a tunable lighting system with automatic transitions throughout the day. Lighting systems are very rarely refined after installation based on actual use. Objective data detailing how the lighting system is used by the actual occupants highlights the opportunities for optimization after installation and provides insight for improving the next design. As use of the data becomes more commonplace, it can be leveraged for design recommendations. The collection of the data required no additional cost beyond the time for examining the data. The analysis revealed several clear opportunities for improvement, including adjustments to the default control setting at night, re-labeling of the control stations, and adjustments to the nighttime fade rate. The patient room occupants were active users of the different zones, dimming options, and manual overrides made available by the lighting system.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91101587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utilization of far-red LED to minimize blue light hazard for dynamic semiconductor lighting","authors":"J. Nie, Zhizhong Chen, F. Jiao, Yifan Chen, J. Zhan, Yiyong Chen, Z. Pan, X. Kang, Yongzhi Wang, Qi Wang, Weimin Dang, W. Dong, Shuzhe Zhou, Xin Yu, Yuzhen Tong, Guoyi Zhang, B. Shen","doi":"10.1080/15502724.2022.2043163","DOIUrl":"https://doi.org/10.1080/15502724.2022.2043163","url":null,"abstract":"ABSTRACT The blue light hazard (BLH) and luminous efficacy of a source ( ) are associated with the photobiological safety and energy saving of light-emitting diodes (LEDs), respectively. In this study, we used genetic algorithm (GA) to optimize the BLH, , and color rendering parameters of five-chip hybrid white LEDs. Based on the optimal results, we used five-chip LEDs to obtain the hybrid white light. Their peak wavelengths were 461.5 (blue), 523.9 (green), 588.2 (orange), 643.3 (red), and 694.2 nm (far-red), respectively. In practice, the blue light hazard efficiency of radiation (BLHER) of the hybrid white light was less than 0.10, which was lower than half of the most common light sources. The ranged from 51.6 to 115.6 lm/W at correlated color temperature (CCT) from 2700 to 6500 K. On average, the CIE general color rendering index (Ra), CIE special color rendering index for the ninth deep red test sample (R9), ANSI/IES TM-30 color fidelity index (Rf), and color gamut index (Rg) of hybrid white light were 91.3, 87.8, 83.3, and 96.7, respectively. The melanopic efficacy of luminous radiation ( ) was tunable in the range of 0.60 to 1.35 mW/lm. These results demonstrated that we used far-red LEDs to fabricate white light with low BLH and relatively high efficiency.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73280332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved Method for Evaluating and Specifying the Chromaticity of Light Sources","authors":"Michael P. Royer, M. Murdoch, Kevin A. G. Smet, L. Whitehead, A. David, K. Houser, T. Esposito, Jason Livingston, Y. Ohno","doi":"10.1080/15502724.2022.2029710","DOIUrl":"https://doi.org/10.1080/15502724.2022.2029710","url":null,"abstract":"ABSTRACT This article describes a method for calculating and specifying light source chromaticity using the International Commission on Illumination (CIE) 2015 10° color matching functions (CMFs), which, according to analysis of existing psychophysical experiment data, can reduce visual mismatch compared to specifications based on the traditional CIE 1931 2° CMFs in architectural lighting applications. Specifically, this work evaluates, documents, and recommends for adoption by lighting standards organizations a supporting system of measures to be used with the CIE 2015 10° CMFs: a new uniform chromaticity scale (UCS) diagram with coordinates (s, t), a measure of correlated color temperature (CCTst), and a measure of distance from the Planckian locus (Dst). It also presents options for updating nominal classification quadrangles. A complete method of this nature has not yet been standardized, which may be contributing to the slow uptake of the CIE 2015 CMFs. The proposed tools are analogous to u, v, CCT, Duv, and the American National Standards Institute (ANSI) C78.377 chromaticity specifications that are all currently defined in the CIE 1960 UCS diagram using the CIE 1931 2° CMFs. While conceptually equivalent, the differences between the current standard method and the proposed st system are important for reducing unintended visual mismatch in the chromaticity of light. The implications of changing chromaticity specification methods are identified by a comparison over a diverse set of real light source spectral power distributions.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86157004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional Differences in the Perception of Daylit Scenes across Europe Using Virtual Reality. Part II: Effects of Façade and Daylight Pattern Geometry","authors":"K. Chamilothori, J. Wienold, C. Moscoso, B. Matusiak, M. Andersen","doi":"10.1080/15502724.2021.1999257","DOIUrl":"https://doi.org/10.1080/15502724.2021.1999257","url":null,"abstract":"ABSTRACT While there is a growing use of complex façade designs in contemporary architecture worldwide and across Europe, little is known about the perceptual effects of these façades and the resulting daylight patterns on occupants, or about how such effects might differ between European latitudes. This study examines the perception of façade and daylight patterns across Europe by replicating a virtual reality (VR) experiment in Norway, Switzerland and Greece, using a mixed experimental design to jointly investigate the influence of different factors on the perception of a daylit interior space. These factors included: façade geometry (within-subject factor with four contemporary façade designs of equal aperture ratio), sky type (clear sky with high or low sun angle, or overcast sky), spatial context (socializing or working), and country (Norway, Switzerland, or Greece). Results showed that, among the manipulated factors, only the façade geometry affected the studied attributes (how pleasant, interesting, exciting, calming, complex, spacious, and bright the space was perceived, and the satisfaction with the amount of view in the space). Regional effects were observed only for reported brightness, with higher evaluations from participants in Greece than in Norway, but are difficult to generalize due to limitations stemming from the use of VR and the conduction of experiments in different seasons (summer and early fall) in the two countries. These findings show that façade design is a crucial feature in our spatial experience, inducing equivalent perceptual effects, such as changes in pleasantness or interest, across Europe, and motivate further research on the perception of brightness.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89307086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"To Measure Is to Know … or Not","authors":"K. Houser","doi":"10.1080/15502724.2022.2029086","DOIUrl":"https://doi.org/10.1080/15502724.2022.2029086","url":null,"abstract":"","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89695614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of Daylight Spectral Power Distribution Based on Correlated Color Temperature: A Comparative Study between the CIE Approach and Localized Procedures in Assessing Non-image Forming Effects","authors":"A. Diakite-Kortlever, Nils Weber, M. Knoop","doi":"10.1080/15502724.2021.1989310","DOIUrl":"https://doi.org/10.1080/15502724.2021.1989310","url":null,"abstract":"ABSTRACT Spectrally and spatially resolved information on daylight is critically important when planning for non-image forming (NIF) responses. Nevertheless, the availability of such data is scarce given the high initial costs and complex on-site maintenance of high-end spectral measurement devices. The CIE (Commission Internationale de l’Éclairage) reconstruction procedure allows for the derivation of the daylight spectral power distribution (SPD) from the chromaticity coordinates or the correlated color temperature ( ). However, several studies have suggested that both the daylight locus and the reconstruction procedure are erroneous, and specifically SPDs with a higher cannot be reproduced accurately. This paper studies the reconstruction accuracy of the SPD of daylight, and contextualizes the findings in relation to NIF effects. The analysis comprises a comparative study to determine the accuracy of the CIE procedure compared to two localized reconstruction procedures, and a sensitivity study to examine the impact of accuracy on the assessment of NIF responses, as represented by all five retinal photoreceptors and expressed in the α-opic efficacy of luminous radiation. The results indicated that a localized procedure, adjusting both the daylight locus and the PCA components of daylight, outperformed the CIE reconstruction method. However, improvement in the reconstruction accuracy had no effect on NIF assessment. The RSMPE for α-opic quantities did not exceed 4% for any procedure. In practical terms, this implies that cost-effective sensors and the representation of spectral properties in sky models with a single value – the correlated color temperature – can be used for NIF purposes. These findings bridge theory and practice by opening up new insights into the understanding of simplified methods used to determine NIF effects of daylight. HIGHLIGHTS Using a localized procedure to define spectral power distribution (SPD) based on correlated color temperature ( ) outperforms the CIE method. Accuracy depends on the computation procedure rather than the daylight locus location. Higher accuracy does not affect the α-opic responses used in defining non-image forming (NIF) effects. Findings confirm the applicability of simplified measuring and representation methods for daylight SPDs. can be used to represent daylight SPD in planning software to assess NIF effects.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88967619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Let Me Count the Light. Accounting for Intensity, Duration and Timing of Light When Predicting Sleep and Subjective Alertness in Field Studies","authors":"S. Peeters, K. Smolders, M. Kompier, Y. D. de Kort","doi":"10.1080/15502724.2021.2001345","DOIUrl":"https://doi.org/10.1080/15502724.2021.2001345","url":null,"abstract":"ABSTRACT Throughout the day, we are exposed to light that varies drastically over time. Correct quantification of the light is important when predicting sleep and subjective alertness in the field, yet doing so, is a complex challenge. In the current manuscript, we explore the feasibility of a novel, practical method to quantify light exposure, based on the data collected in two field studies (in late spring and winter). Data include indicators of sleep, subjective alertness, and personal luminous exposure. We explored Time above Threshold (TaT) and Mean Light Timing above Threshold (MLiT) metrics, as well as their interaction, to quantify intensity, timing, and duration of light in testing not only circadian but also acute alerting effects of light in the field during office hours. For both measures, sensitivity analyses were performed across a large range of illuminance thresholds. The aim was to explore if these analyses would render indications for (a range of) effective thresholds, and to test if this alternative method of quantifying light would outperform simple averaging over specific time intervals. Despite the relatively small data set, the current approach seems promising particularly for predicting sleep: models performed slightly better than traditional models using average light exposure as predictor. More importantly, this method takes into account intensity, duration and timing, providing more detailed insights in the relation between luminous exposure and different outcome measures. We encourage this method to be explored further with larger data sets, discuss shortcomings of the current analyses and suggest potential directions for improvement.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85474525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the Visibility of Architectural Features for People with Low Vision -A Quantitative Approach.","authors":"William B Thompson,&nbsp;Robert A Shakespeare,&nbsp;Siyun Liu,&nbsp;Sarah H Creem-Regehr,&nbsp;Daniel J Kersten,&nbsp;Gordon E Legge","doi":"10.1080/15502724.2021.1890115","DOIUrl":"https://doi.org/10.1080/15502724.2021.1890115","url":null,"abstract":"<p><p>Most people with low vision rely on their remaining functional vision for mobility. Our goal is to provide tools to help design architectural spaces in which safe and effective mobility is possible by those with low vision---spaces that we refer to as <i>visually accessible</i>. We describe an approach that starts with a 3D CAD model of a planned space and produces labeled images indicating whether or not structures that are potential mobility hazards are visible at a particular level of low vision. There are two main parts to the analysis. The first, previously described, represents low-vision status by filtering a calibrated luminance image generated from the CAD model and associated lighting and materials information to produce a new image with unseen detail removed. The second part, described in this paper, uses both these filtered images and information about the geometry of the space obtained from the CAD model and related lighting and surface material specifications to produce a quantitative estimate of the likelihood of particular hazards being visible. We provide examples of the workflow required, a discussion of the novelty and implications of the approach, and a short discussion of needed future work.</p>","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15502724.2021.1890115","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10463888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Road Marking Contrast Threshold Revisited","authors":"R. Spieringhs, Kevin A. G. Smet, I. Heynderickx, P. Hanselaer","doi":"10.1080/15502724.2021.1993893","DOIUrl":"https://doi.org/10.1080/15502724.2021.1993893","url":null,"abstract":"ABSTRACT Sufficient contrast between road surface and road markings is key for a safe and comfortable driving experience. This calls for a comprehensive and well established contrast (threshold) model, which ideally results in a single contrast threshold value independent of object angular size or road luminance. The contrast threshold model introduced by Adrian is still commonly used in road lighting. More recently, new contrast metrics that also predict supra-threshold contrast visibility have been proposed, but the corresponding visibility thresholds are not yet known. In the present study, participants are presented a rendering of a highway, including road marking arrows of various size and luminance and were asked to indicate the direction of the arrow. The luminance of the road surface, acting as background for the markings, was varied too. Due to the very low luminance values and the very small differences in luminance, measurement accuracy and calibration issues require special attention. The results show good agreement with Adrian’s visibility model (R2 = 0.75) in terms of luminance contrast, background luminance and size. In addition, we used our experimental data to define contrast thresholds for several other existing image based contrast models. Unfortunately, it seems to be impossible to state one unique threshold contrast value independent of object angular size and road luminance.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78106721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Certainty and Doubt","authors":"K. Houser","doi":"10.1080/15502724.2021.1988819","DOIUrl":"https://doi.org/10.1080/15502724.2021.1988819","url":null,"abstract":"Researchers and practitioners in fields that include lighting science and illuminating engineering endeavor to balance objectivity with skepticism. Conviction is warranted when a position can be supported by robust and reliable data—e.g., vision deteriorates with age. Skepticism is warranted when supporting data are incomplete or unconvincing. For example, while there is no doubt that light mediates nonvisual responses such as melatonin suppression, the manner and degree to which that knowledge should inform lighting practice is less clear. When recommendations run too far ahead of what is known with conviction, it is prudent to be skeptical. Authors and speakers also persuade their audiences through narratives—stories that connect carefully selected sets of supposedly true observations. Conclusions are convincing when they can be supported by credible data, yet data tend to be curated, partial, and even when exhibiting internal validity may not apply to other contexts. Scientific viewpoints tend to be justified with intrinsically limited data that is chronicled through cogent narratives. For people seeking the ground truth, this process is exciting. Ideas are interrogated, caveats are stated, alternative explanations are considered, and degrees of both certainty and doubt are weighed. To someone outside of the scientific process, doubt may appear troubling, and certainty may be reassuring, but to a researcher, it is quite the opposite. Doubt pushes science toward deeper understanding, whereas certainty can be the bane of curiosity that impedes progress. While more research and more data will always be needed, considered choices can be made based on what is known. It is healthy to acknowledge that knowledge is incomplete, letting neither rational uncertainty nor irrational conviction stand in the way of progress. When faced with new data, changing one’s mind is not a failure, but a sign of growth. Formal discourse unfolds in the scientific literature, which relies on peer reviews to assess the credibility and veracity of scientific works. But the end goal of scientific works, especially in applied journals like LEUKOS, is not publication of the article, but the potential of the work to positively influence the world. This requires transfer of ideas or technologies from the scientific community to the public, a step that sometimes meets resistance. In recent years, there has been widespread erosion in the objective standards for truth. Public opinions are shaped by personal beliefs that are themselves influenced by appeals to emotion. Half-truths and outright falsehoods are sometimes promulgated to misinform. Does stating something false makes it true? An impartial reader might answer “no,” but in important domains of life that include politics and public policy, there is a blurry line between the rational and the fanciful. The repetition of false statements repeated ad nauseam and with conviction, has for some sowed seeds of doubt in science itse","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76278934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}