Leukos最新文献

{"title":"Effect of Correlated Color Temperature and S/P-ratio of LED Light Sources on Reaction Time in Off-axis Vision and Mesopic Lighting Levels","authors":"E. Vicente, B. Matesanz, M. Rodríguez-Rosa, A. M. Sáez, S. Mar, I. Arranz","doi":"10.1080/15502724.2021.1970580","DOIUrl":"https://doi.org/10.1080/15502724.2021.1970580","url":null,"abstract":"ABSTRACT The increasing replacement of traditional lamps by LED technology opens the door to research into visual performance under their multiple possible spectral power distributions. The correlated color temperature and S/P-ratio are considered parameters characterizing the spectrum of a light source. The lack of firm conclusions motivates the analysis in this work of the influence of LED spectrum, which is defined by the correlated color temperature and S/P-ratio, on a representative night-driving task, visual reaction time. A two-channel and four primaries photostimulator was used as set-up for measuring reaction time in off-axis vision, at mesopic illumination conditions and for a range of stimulus contrasts. The experimental conditions included a wide range of correlated color temperatures, ranging from 1870 to 6350 K, and different S/P-ratios for the same temperature. A total of 16 young subjects participated in the experiments. The results show significant shorter reaction times for those conditions in which the spectrum has greater short-wavelength content. This is corroborated by the greater stimulation of rods and S-cones obtained in the calculation of their excitation level. However, the definition of the spectrum using the correlated color temperature and S/P-ratio does not equally define the results obtained. For the same temperature, a higher S/P-ratio provides lower reaction time values, but for the same S/P ratio reaction time is independent of the temperature. LED light sources with high short-wavelength content provide faster response on the basis of a greater excitation of rods and S-cones. The S/P-ratio is the best parameter to justify the effect of spectrum on reaction time, as considers the spectral sensitivity of the visual system in its calculation.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79830599","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":"Ethics and Fallacies of Human-Centric Lighting and Artificial Light at Night","authors":"K. Houser","doi":"10.1080/15502724.2021.1951021","DOIUrl":"https://doi.org/10.1080/15502724.2021.1951021","url":null,"abstract":"Human-centered design is a problem-solving approach that focuses on people first—their productivity, comfort, and user experience. A bicycle should be designed with pedals, seat, handlebars, brakes, and gear shifters in ergonomically comfortable positions. The hardware and software that comprise tablets and cellular devices should intuitively enable a positive user experience. Placing humans first is a sensible approach in many design scenarios, especially when the device or technology will not substantially interact with non-human life. With lighting, however, human-centricity may come with collateral damage. Through Earth’s web of life, we rely on other forms of life for our own survival. As apex predators, humans consume all kinds of plants and animals, which themselves are part of wider and interconnected ecosystems consisting of all manner of biotic and abiotic components. Regrettably and incontrovertibly, some lighting designed to support a subset of human needs causes unintended negative effects on human life, and even worse consequences to nonhuman life. Artificial light at night (ALAN) is offered as a case in point. Notwithstanding some practical and aesthetic benefits, ALAN exerts direct negative effects on people. The human body tells time by observing nature’s rhythm of light and dark. Electric lighting that is asynchronous with natural cycles of day and night may interfere with our natural biological clocks, thus impairing human functioning on timescales of days, weeks, and years. Simultaneously, ALAN disrupts natural ecosystems. Flora and fauna rely on Earth’s predictable patterns of day and night to regulate life-sustaining behaviors such as sleep, eating, reproduction, and hiding from predators. ALAN disrupts those behaviors. Some species gain a short-term advantage at the expense of other species, thus disrupting ecosystems. These disturbances may not show immediate or obvious effects on humans, but this is more reflective of the inability of human science to predict, detect, and measure such effects. On timescales of decades and generations, we should expect the consequences to come back to us. Holistic consideration of human-centric lighting should look beyond short-term effects of light on human visual, emotional, behavioral, and biological outcomes. While ethical considerations related to conserving habitats for turtles, birds, insects, fishes, and reptiles are salient, this is not mere altruism. Nor is this just romanticism about the beauty of the night sky. At root is also pragmatism. It is in our self-interest to preserve the ecosystems and biodiversity that support human life, lest today’s design decisions become tomorrow’s liabilities. How might one practice lighting if short-term considerations about human needs yield to, or better, integrate with, long-term considerations about planetary health? To what degree, if at all, should building facades and monuments be illuminated? To what degree should window shading devices","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83660843","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":"On Illumination Vector Quantities Due to Area Light Sources: Comparison of Two Calculation Approaches","authors":"R. A. Mangkuto, M. Koerniawan","doi":"10.1080/15502724.2021.1957688","DOIUrl":"https://doi.org/10.1080/15502724.2021.1957688","url":null,"abstract":"ABSTRACT The concept of illumination vector quantities at a given point in three-dimensional space has been proposed since long time ago, but it is mostly described for scenes with point light sources. In real scenes with area light sources, numerical approximations are required to estimate the illumination vector quantities, which can be done by discretising the area into an array of point sources. Two different approaches are proposed in this study; Approach 1 is applicable in the design phase, where the positions of the source and receiver point are exactly known. Approach 2 is applicable during field measurement, based on the obtained cubic illuminances. This study aims to determine the required number of point source elements in the computation and to investigate the difference between both calculation approaches. The proposed concept is demonstrated using a scenario with horizontal, square source and a scenario with vertical, rectangular source, with various luminous intensity distribution patterns, by observing various illumination vector quantities. Grid sensitivity analyses suggest that the largest grid size satisfying the five-to-one approximation rule shall yield quantities that converge within no more than 5% to the final value. For a given size of area source, at a given distance, the differences of illumination vector quantities obtained from both calculation approaches are expected to be approximately the same, regardless the luminous intensity distribution. The estimation of cylindrical illuminance is generally more accurate than that of scalar illuminance.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90121024","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":"Discomfort Glare from a Cyclic Source in Outdoor Lighting Conditions","authors":"Joffrey Girard, C. Villa, R. Brémond","doi":"10.1080/15502724.2021.1954531","DOIUrl":"https://doi.org/10.1080/15502724.2021.1954531","url":null,"abstract":"ABSTRACT Many models of discomfort glare have been proposed for outdoor lighting applications. Most of them were built from data collected in the laboratory in static situations, with motionless light sources, which main characteristics (luminance, size and position) were constant over time. However, on the road at night, drivers are moving with multiple sources around them. To fill the gap between static situations and more realistic ones, four psychophysic experiments were carried out in a laboratory to investigate the impact of the cyclic variations of several light source characteristics (its luminance, eccentricity and solid angle) on the discomfort glare. The temporal frequencies have been chosen representative of outdoor lighting conditions, up to 2.6 Hz. No impact of the dynamics of the glare source was found, except for a source with variable luminance at a low frequency ( ).","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81926827","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 Impact of Exterior Surround Detail on Daylighting Simulation Results","authors":"R. Sadeghi, R. Mistrick","doi":"10.1080/15502724.2021.1947313","DOIUrl":"https://doi.org/10.1080/15502724.2021.1947313","url":null,"abstract":"ABSTRACT The accuracy of daylighting simulations for the built environment strongly depends on the modeling of the exterior surround. The practice of modeling a space with a flat ground surface with little or no external architectural or landscape elements, particularly early in the design phase, is often applied. In this study, this approach and a number of different levels of detail for modeling the exterior surround were investigated by comparing real-life empirical measurements with their corresponding simulation results. A total of 13 different exterior views were studied under 15 different sky/seasonal conditions to investigate the contribution of the surrounding features to the daylight delivered inside a small office. These features were classified into one of four different groups – sky, architectural structures, standing vegetation, and horizontal ground. Five of these locations were chosen for further simulation by applying six levels of detail to the exterior surround in a simulation model. The results reveal that ignoring exterior surround objects (common practice for some) yielded an average error of 67.9%, while a high level of detail (which applied high polygon vegetation representations) resulted in an average error of only 11.3%. A detailed model of the surround with the IES LM-83 suggested method of modeling trees resulted in an average error of 22.8%.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88475086","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 Usefulness of Near-Field Goniophotometry Data to Assess Illuminances and Discomfort Glare in Indoor Lighting","authors":"L. Simonot, F. Reux, S. Carré, C. Martinsons","doi":"10.1080/15502724.2021.1925129","DOIUrl":"https://doi.org/10.1080/15502724.2021.1925129","url":null,"abstract":"ABSTRACT In lighting simulations, a luminaire is usually modeled using a luminous intensity distribution emitted by a single-point source. This so-called far-field approach is valid as long as the dimensions of the luminaire are much smaller than the distance to the calculation surface. This assumption is generally not met in standard indoor lighting and may lead to significant errors in the prediction of illuminances and discomfort glare. This work describes a practical near-field approach based on splitting the luminaire into N point sources. The errors in relation to the near field (infinite value of N) are evaluated as a function of N. This approach generates a more accurate assessment of the Unified Glare Rating in the case of luminaires with non-uniform emission.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82343199","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":"Output Reduction over Time of Germicidal UV-C Lamps Used for Treating Agricultural Crops","authors":"M. Rea, John D. Bullough, A. Bierman","doi":"10.1080/15502724.2021.1921594","DOIUrl":"https://doi.org/10.1080/15502724.2021.1921594","url":null,"abstract":"ABSTRACT It is important in understanding the potential benefits of ultraviolet (UV-C) field applications for control of powdery mildew to know how long the lamps will last before replacement. We conducted a laboratory evaluation of a sample of low-pressure discharge germicidal UV-C lamps that have been used in field trials to control strawberry powdery mildew. None of the lamps tested failed to start after more than a year of operation. The degradation of UV-C output followed trends similar to those described by the manufacturer. Based on these measurement data and on the long history of this lamp technology, we predict that these lamps can continue to perform in the field after the manufacturer’s rated life of approximately 10,000 hours of continuous operation, by reducing the speed of application to deliver the prescribed UV-C dose. With protective sleeves, these low pressure discharge UV-C lamps can be expected to last for many years of service.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75971356","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":"Visual Performance Models in Road Lighting: A Historical Perspective","authors":"R. Brémond","doi":"10.1080/15502724.2019.1708204","DOIUrl":"https://doi.org/10.1080/15502724.2019.1708204","url":null,"abstract":"ABSTRACT The use of visual performance models in road lighting is an old idea: it was first proposed in the 1930s by Waldram with the Revealing Power, and by Roper and Howard who used the notion of visibility distance. The Visibility Level (VL) concept was then proposed by Blackwell, and the Relative Visual Performance by Rea and Ouelette. At the turn of the 21th century, some standards have considered using the VL in order to rate lighting installations through the Small Target Visibility concept. However, the use of visual performance indexes in lighting standards was recently withdrawed, which raises a question: what happened?","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80277289","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":"Window Size Effects on Subjective Impressions of Daylit Spaces: Indoor Studies at High Latitudes Using Virtual Reality","authors":"C. Moscoso, K. Chamilothori, J. Wienold, M. Andersen, B. Matusiak","doi":"10.1080/15502724.2020.1726183","DOIUrl":"https://doi.org/10.1080/15502724.2020.1726183","url":null,"abstract":"ABSTRACT Daylight provision to the indoor space is affected by different building elements that cannot be fully controlled by the users, such as the window size of a space. The dimensions of the fenestration not only affect the lighting levels, but they also affect how the space is perceived by its users. The present study examines three different window sizes via virtual reality, to study how they affect the perception of both a small and a large space at high latitudes. Additionally, two context scenarios (socializing and working), as well as three different sky types (overcast sky and clear skies with either high or low sun angle) were evaluated. The experimental study applied a mixed design with within-subjects and between-subjects factors. A total of 150 participants evaluated the scenes using a Likert-type scale to rate eight different subjective attributes. The statistical results showed that both window size and space type significantly affect the participants’ spatial perception, as well as their satisfaction with the amount of outside view. Larger windows led to more positively evaluated spaces for all studied attributes. Moreover, a significant interaction was found between window size and type of space for the satisfaction with the amount of view in the space, indicating that the window size was dependent on the type of space in which the windows are located. Specifically, the window sizes were rated higher in the small space than in the large space for the evaluation of amount of view. The findings show that window size affects how people perceive a space, and additionally, that other spatial features, such as space type, affect window size preferences.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89300367","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":"Preference for the Color Rendition of Skin","authors":"K. Houser","doi":"10.1080/15502724.2021.1933857","DOIUrl":"https://doi.org/10.1080/15502724.2021.1933857","url":null,"abstract":"Quite a bit is known about group preference for how light sources render object colors, as distilled into Annexes E and F of TM-30-20 (ANSI/IES 2020). One area that is weakly substantiated, however, is group and subgroup preferences for how light sources render skin. This is a conspicuous shortcoming because people are intended to be the primary beneficiaries of lighting. Preference for the color rendition of skin is a challenging scientific problem with cultural implications. Skin spectral reflectance functions (SRFs) are generally reported as averages over a small area of skin, usually measured on some part of the arm or hand. While people with darker or lighter skin have variation in mean reflectance, the spectral features do not vary as much as one might expect (e.g., Angelopoulou 2001; Cooksey et al. 2019). The presumed implication is that it may be possible to predict reasonably well the color shift of a range of skin SRFs with a small number of samples. With skin, however, average shifts should not be expected to tell the whole story. If the color of a toy or piece of clothing is altered by a light source, it is not personal. But if a light source distorts a person’s skin in a way that is undesirable, then that is intrinsically personal. Evaluating skin rendition is further complicated because skin is not homogenous and cannot be represented in a single SRF, skin tone is dynamic based on blood flow and other factors, and preference varies with ethnicity, may vary with race, may be informed by culture, and may vary with individual characteristics. For example, some people may prefer the ruddier skin appearance associated with red-chroma-enhancing light sources, while others may not (e.g., those with neutral or cool undertones, mottled skin, or a skin condition). There is some evidence for cultural differences—e.g., some evidence suggests that, on average, Caucasians prefer a color-shift that causes a ruddier complexion more so than Asians (Wei et al. 2014). TM-30-20 does not include a specific design intent or design guidance related to skin appearance. This not because there is lack of interest, but because there is not enough knowledge to produce defensible recommendations. “More research is needed” is a common cry among researchers, but in this case the cry is true. It will be inspiring if future work includes an ethnically, racially, and culturally diverse research team that contributes to the conceptualization and design of new experiments, and a diverse set of participants that permits analyses based on ethnicity, race, and culture. This sort of granular information would provide deeper understanding of how different groups of people experience light and may open opportunities for spectrally tailored lighting solutions.","PeriodicalId":49911,"journal":{"name":"Leukos","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85238188","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}