Leukos最新文献

{"title":"Preferred luminance distributions in open-plan offices in relation to time-of-day and subjective alertness","authors":"Christel de Bakker, M. Aarts, H. Kort, E. van Loenen, A. Rosemann","doi":"10.1080/15502724.2019.1587619","DOIUrl":"https://doi.org/10.1080/15502724.2019.1587619","url":null,"abstract":"ABSTRACT Dynamic lighting is one of the new trends in lighting research; providing the right lighting level at the right time could possibly increase the alertness and performance of office workers. However, they might have preferences that deviate from this “healthy” lighting. Simultaneously, the building environment becomes increasingly automated, with occupancy-based control as one of the most well-known examples to reduce offices’ lighting energy consumption. Nevertheless, preferences for lighting levels in the unoccupied area of the multi-occupant office space have not been addressed yet. Therefore, we studied luminance distribution preferences in relation to time of day and subjective alertness (SA) in a single occupancy scenario. Participants (N = 30) set the surrounding and background lighting six times a day as we first probed for SA. Our results clearly showed that a subset preferred varying luminance distributions; participants had fluctuating feelings of alertness, too. Preferences deviated sometimes from the typical dynamic lighting scenarios, suggesting that they do not always prefer healthy lighting. Moreover, we identified an effect of SA on the preferences, both with and without controlling for time of day. Hence, this study showed that we need to address these two factors when we want to provide satisfactory lighting conditions in case the office is not fully occupied. These are likely to affect other lighting preferences and therefore deserve more attention from research. Because we identified large individual differences, we suggest personalizing dynamic scenarios as the focus of future research.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"2017 1","pages":"3 - 20"},"PeriodicalIF":3.6,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83627466","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":"Calibration and Validation of Climate-Based Daylighting Models Based on One-Time Field Measurements: Office Buildings in the Tropics","authors":"G. Quek, J. Jakubiec","doi":"10.1080/15502724.2019.1570852","DOIUrl":"https://doi.org/10.1080/15502724.2019.1570852","url":null,"abstract":"ABSTRACT Calibrated climate-based lighting simulation models of buildings have the capacity to perform an essential role in postoccupancy evaluations, such as annual frequency assessments of daylighting quality and visual discomfort. However, in most postoccupancy case studies the role of lighting analysis is temporally limited by instantaneous measurements or limited in scale by requiring constant monitoring with expensive sensors. It is challenging to build calibrated models based on point-in-time measurements due to the presence of electric lighting, transient use of dynamic shades, limited information on the material specifications, and short durations of accessibility to the spaces being studied. The authors propose and present a calibration process for annual daylighting and electric lighting simulation models based on one-time field measurements of large daylit and electrically lit spaces exemplified through a data set of 540 individual office desks across 10 office spaces. The calibration process includes measuring lighting, physical, and material data during a one-time visit that are used to calibrate high dynamic range images and lighting simulation models using actual weather data. The calibration accuracy is validated based on measured and simulated luminance and illuminance data. Comparing measured and simulated illuminance, relative root mean squared error (RMSE) values were 25.8% and 45.5% for horizontal and vertical measurements, respectively. When tracking errors using log10(illuminance), approximating human perceptual differences, errors of 4.3% and 6.8% were achieved. Vertical illuminance was found to vary more with measured data due to the uncertainty of monitor screen luminances. The authors aim to achieve calibrated lighting models that are reliable enough to be used in assessing the relationship of annualized lighting metrics to participants’ long-term perceptions of lighting quality, thereby enabling simulation models to be used in the postoccupancy evaluation process of building lighting. This article demonstrates that measured data through one-time visits can be utilized to build reliable calibrated lighting simulation models to integrate long-term annual lighting results in postoccupancy evaluations.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"47 1","pages":"75 - 90"},"PeriodicalIF":3.6,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91125700","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":"Change of Gamut Size for Producing Preferred Color Appearance from 20 to 15000 lux","authors":"Wenyu Bao, M. Wei","doi":"10.1080/15502724.2019.1587621","DOIUrl":"https://doi.org/10.1080/15502724.2019.1587621","url":null,"abstract":"ABSTRACT Numerous efforts have been made to investigate how light source color rendition affects color preference. Though the effect of light level on color appearance (known as the Hunt effect) was found in 1952, most studies investigating color preference under light sources only employed a single illuminance level and the illuminance levels were typically between 200 and 1000 lux. This article reports two psychophysical experiments that were designed to investigate how light source color rendition affected color preference across a wide range of illuminance levels, from 20 to 15,000 lux. The observers compared the color appearance of an artwork under nine nearly metameric light stimuli with a correlated color temperature (CCT) of 3000 K at different illuminance levels. These light stimuli were carefully designed to have different abilities to enhance the chroma of red and green colors, so that they had different gamut areas R g (between 100 and 124 in Experiment 1 and between 99 and 117 in Experiment 2). It was found that the illuminance level significantly affected the observers’ judgments, with a light stimulus with a greater R g being preferred at a lower light level. The light stimuli with an R g beyond 100 were preferred at the light levels from 20 to 5000 lux, whereas those with an R g around 100 were preferred at very high light levels (i.e., 10,000 and 15,000 lux). This suggested that the preference to the stimuli with an R g beyond 100, as found in many past studies, was likely due to the relatively lower illuminance levels in comparison to the daylight illuminance levels. In addition, the calculations of the color attributes of the artwork under the preferred stimuli suggested that CIECAM02 may overestimate the effect of light level on color appearance, especially when the light level was very high, which merits further investigations.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"268 1","pages":"21 - 42"},"PeriodicalIF":3.6,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75924140","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":"Sensory Evaluation of Lighting: A Methodological Pilot","authors":"Magdalena Boork, J. Nordén, M. Nilsson Tengelin, K. Wendin","doi":"10.1080/15502724.2020.1813037","DOIUrl":"https://doi.org/10.1080/15502724.2020.1813037","url":null,"abstract":"ABSTRACT Current standards for light environments are based on technical requirements, e.g. luminance, uniformity, and illuminance, and do not necessarily describe all parts of the light experience to ensure visual comfort from a user perspective. Including experience-related requirements would most likely yield better lighting comfort. To do that, new methods for specifying and measuring the user experience are needed. This paper describes a pilot study exploring a new method to analytically assess perceived lighting properties by using a trained human panel and thus make human assessments more objective. The methodology is built on established sensory methods, where the human senses are used in product assessments, traditionally applied within e.g. the food, packaging, and car industries. An analytical panel comprising eight persons fulfilling specific selection criteria were recruited and trained to assess lighting products in a multi-sensory laboratory. The results show that the panelists were able to assess lighting by distinguishing between attributes and products. Significant differences were identified between the different luminaires, both in terms of sensory and physical properties, e.g. readability and glare. Conclusively, analytical sensory methods can be applied to lighting to assess luminaires in a non-subjective way. Physical and sensory attributes do not, however, always co-vary, which shows that data from physical and sensory measuring methods provide complementary information about light quality. This knowledge may in turn be applied in tools supporting the communication between different professions in lighting design and procurement to promote light environments that are both energy efficient and desirable from an end-user perspective.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"69 1","pages":"66 - 82"},"PeriodicalIF":3.6,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76340460","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":"Error and Uncertainty Analyses of Reference and Sample Reflectances Measured with Substitution Integrating Spheres","authors":"R. A. Mangkuto, Revantino, Zhafirah Ajrina","doi":"10.1080/15502724.2020.1831391","DOIUrl":"https://doi.org/10.1080/15502724.2020.1831391","url":null,"abstract":"ABSTRACT The use of integrating sphere has been known as a method to measure hemispherical reflectance of a material sample. Mathematical expressions of such reflectance are available in literature, but most of them are not explicit in describing the relation between reflectance and the relevant input variables. This study aims to derive closed-form expressions for determining reference and sample reflectances, provided the irradiance values when the sample and the reference are measured using substitution integrating sphere. Moreover, this study also aims to determine the relative error in reflectance measurement when the fractional area of the ports is neglected, and to derive uncertainty expressions of reflectances due to uncertain irradiance values. The derived expressions have been verified with theoretical calculation tests comprising 10,000 random combinations of input variables. The proposed expressions, together with the error and uncertainty analyses, are expected to be applicable for low-cost, self-assembled integrating spheres.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"15 1","pages":"52 - 65"},"PeriodicalIF":3.6,"publicationDate":"2020-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82115011","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":"Flow of Light: Balancing Directionality and CCT in the Office Environment","authors":"E. Hansen, Mihkel Pajuste, Emmanouil Xylakis","doi":"10.1080/15502724.2020.1808014","DOIUrl":"https://doi.org/10.1080/15502724.2020.1808014","url":null,"abstract":"ABSTRACT Human perception and vision have evolved in response to dynamic daylight, a combination of radiation from direct sunlight and diffuse skylight, which has created a flow of variations in light, in terms of direct:diffuse distribution, intensities and spectrum. This study investigates the qualities of the flow of light in an office after adding ceiling-mounted spotlights (32° tilt angle) to traditional diffuse ceiling panels. The intention is to create a flow of task light – a light-zone at each work-plane – complementing the directionality of the natural daylight inflow from the windows. An experiment was carried out in an office, in two parts. Four ratios of direct:diffuse light were tested by 30 people. Then one ratio was tested in five combinations of high, neutral and low color temperatures by 15 people in two daylight situations: overcast and clear sky. The visual light quality and perceived atmosphere of the office environment was tested through questionnaires, reaction cards and semi-structured interviews. The direct flow of light is recommended to be more than 15% of the total illuminance at the work-plane to provide the distinct visual appearance of modeling and a cozier atmosphere, which is preferable for socializing, and less than 45% to avoid glare and high contrast for visual tasks. Direct warm and diffuse cool lighting were perceived as the most natural but were not always preferred. There is an indication of slight preference for cooler ambient lighting in clear sky situations and warmer ambient lighting in overcast situations. Especially the preference in relation to sky conditions needs to be further investigated. A field study will implement these findings in a double dynamic lighting concept responding to daylight level and sky character. Strong individual preferences for combinations of color temperatures was identified, this open up new research areas for personalized flows of light in future dynamic lighting designs.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"11 1","pages":"30 - 51"},"PeriodicalIF":3.6,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90341153","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":"A Database Retrieval Method for the Prediction of Reduced Luminance Coefficient Tables of A Road Surface Based on Measurements in Situ","authors":"Wenyi Li, Yang Hu, Yajing Ji, Muqing Liu, Haiping Shen","doi":"10.1080/15502724.2020.1813038","DOIUrl":"https://doi.org/10.1080/15502724.2020.1813038","url":null,"abstract":"ABSTRACT The in-situ measurements for r-tables have attracted special attention owing to their advantages, including increased speed, simplicity of use, and nondestructive road effects. This study presents a database retrieval method proposed for the construction of a full-scale r-table from an r-table database with 25 r coefficients used as input parameters. The proposed method was used in an in-situ, r-table measurement device as a data processing algorithm. To evaluate the accuracy of the proposed method, we performed a) a table-to-table comparison of Q0, S1, and r-tables constructed by different methods and b) comparisons of calculated luminance values (Lave, U0, Ul ) for a typical road-lighting scenario based on the use of different r-tables. The table-to-table comparison results indicate that following the application of the proposed method, its calculated Q0, S1, and r-table values were very close to their actual values (EQ0 = 2.1%, ES1 = 5.0%, Error = 2.3%). Moreover, the proposed method also exhibits an improved luminance response and achieves a 2.1% difference in Lave , a 3% difference in U0 , and a 1.8% difference in Ul . This study proves that the proposed database retrieval method improves the model prediction accuracy.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"9 1","pages":"21 - 29"},"PeriodicalIF":3.6,"publicationDate":"2020-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74347079","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":"A Window View Quality Assessment Framework","authors":"Won Hee Ko, M. Kent, S. Schiavon, Brendon Levitt, Giovanni Betti","doi":"10.1080/15502724.2021.1965889","DOIUrl":"https://doi.org/10.1080/15502724.2021.1965889","url":null,"abstract":"ABSTRACT The views that windows provide from inside a building affect human health and well-being. Although window view is an important element of architecture, there is no established framework to guide its design. The literature is widely dispersed across different disciplinary fields, and there is a need to coalesce this information into a framework that can be applied into the building design. Based on the literature, we present a framework for what constitutes “view quality.” At the basis of our framework, we propose three primary variables: View Content (the assessment of visual features seen in the window view); View Access (the measure of how much of the view can be seen through the window from the occupant’s position); and View Clarity (the assessment of how clear the view content appears in the window view when seen by an occupant). Each variable was thematically derived from different sources including daylighting standards, green certification systems, and scientific research studies. We describe the most important characteristics of each variable, and from our review of the literature, we propose a conceptual index that can evaluate the quality of a window view. While discussing the index, we summarize design recommendations for integrating these three variables into the building process and identify knowledge gaps for future research.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"34 1","pages":"268 - 293"},"PeriodicalIF":3.6,"publicationDate":"2020-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88446593","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":"Uncertainty Analysis of Cylindrical Illuminance Approximation","authors":"R. A. Mangkuto","doi":"10.1080/15502724.2019.1619574","DOIUrl":"https://doi.org/10.1080/15502724.2019.1619574","url":null,"abstract":"ABSTRACT Cylindrical illuminance has long been known as a metric of light modeling in three-dimensional space. Though it is possible to employ a dedicated meter to measure this metric, it is considered more practical to measure cubic illuminance data on the field. However, the cubic illuminance method is an approximation, which may yield errors relative to the true value. This article therefore presents uncertainty analysis of the calculation of cylindrical illuminance at a point due to multiple random point sources, using three different approaches. It is found that the original approach with the sum of individual cylindrical illuminance yields results highly similar to the true values. A similar approach only considering the total cubic illuminance yields uncertainty and is comparable to the alternative approach using averaged vertical illuminance. Applying the last approach with a larger number of axes leads to higher accuracy. To ensure very low uncertainty, in-field cylindrical illuminance measurement should be performed on at least 16 axes on the x–y plane.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"38 1","pages":"267 - 278"},"PeriodicalIF":3.6,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76323612","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":"The Effect of Texture on Brightness Perception in Simulated Scenes","authors":"J. Barraza, Andrés Martín","doi":"10.1080/15502724.2019.1674661","DOIUrl":"https://doi.org/10.1080/15502724.2019.1674661","url":null,"abstract":"ABSTRACT It is known that there is a black-white asymmetry in the psychophysical response; this is such that decrements are represented in the visual system by a larger magnitude than increments, that have an equal-magnitude deviation from the background. One interesting prediction arises from this black-white asymmetry that is: an homogeneously textured surface in which each dot belongs to a range of grays, and whose mean luminance is L, will be perceived as darker than a uniform surface with the same luminance L. We propose to explore this effect and analyze its potential consequences on the brightness perception of surfaces in illuminated scenes. For this purpose, we performed two experiments: in the first one, we showed that the texture biases the perception of surface brightness. In the second one, we showed, by testing the effect on simulated 3D realistic scenes, that textured walls are perceived as darker than identically painted walls with soft finish.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":"36 1","pages":"279 - 287"},"PeriodicalIF":3.6,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75178796","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}