bluuebunny/crossref_metadata_2025 huggingface dataset:
IMPLEMENTATION OF A RECONSTRUCTED SPECTRAL SKY DEFINITION IN A LIGHT SIMULATION TOOL AND COMPARISON TO MEASUREMENTS
Authors: Orman A. , Safranek S. , Pierson C.
Published: January 2024

This study assesses the impact of the sky spectral power distribution (SPD) on the output accuracy of Lark, a spectral light simulation tool. Lark was developed to quantify ipRGC-influenced light responses of people in built environments. The three types of sky SPDs tested are measured sky SPDs, the CIE D65 Standard Illuminant, and reconstructed sky SPDs provided by the Occupant Wellbeing through Lighting (OWL) tool. The accuracy of these three types of sky SPD is assessed through comparing the simulated spectral irradiance and derived non-visual response indicators against measurements. The results show that all simulations have a relative error within ±20%. However, the OWL SPDs do not improve the accuracy of spectral irradiance or derived non-visual responses over the other two approaches. The analysis of non-visual response indicators reveals that both the D65 Illuminant and the OWL SPDs underestimate short wavelengths of the sky spectrum under clear and intermediate skies.
INTEGRATIVE LIGHTING IN OFFICES: RESULTS FROM FIELD MEASUREMENTS AND ANNUAL DAYLIGHT SIMULATIONS
Authors: Giovannini L. , Lo Verso V. , Pellegrino A. , Valetti L. , Daltrozo J.
Published: January 2024

Integrative lighting conditions in four offices of the university ‘Politecnico di Torino’ (Turin, Italy) were investigated, in terms of combination of daylighting and electric lighting. The research addressed two objectives: (i) to verify if the lighting conditions could meet the recommendations proposed in recent literature (CIE or WELL protocol) concerning light exposure for appropriate non-visual responses (melanopic equivalent daylight illuminance m-EDI); ii) to assess the influence on integrative lighting (photopic and melanopic illuminances) played by daylighting as a function of different room depth and orientation, by electric lighting, as a function of different lighting systems and by the combination of both. Electric lighting was assessed through field measurements, while daylighting through annual simulations using LARK v2. Results showed that CIE requirements were not met in any office, while WELL recommendations were met only for the positions closest to the window (within 1.87 m).
4-MONTHS FOLLOW-UP OF THE PERFORMANCE OF LUMINESCENT ROAD MARKINGS
Authors: Villa C. , Marquet P. , Saint-Jacques E. , Bremond R. , Eymond F.
Published: January 2024

The performance of photoluminescent paints for road marking have been evaluated from calibrated camera measurements during four months in outdoor conditions. A method was developed to quantify the performance over time depending on the external conditions (lighting, temperature, rain). Findings confirm the influence of night-time illumination. A simple model is proposed to predict the time during which the luminescent paint is more luminous than a traditional one based on the illuminance averaged during the night.
SKYSPECTRA: AN OPENSOURCE DATA PACKAGE OF WORLDWIDE SPECTRAL DAYLIGHT
Authors: Balakrishnan P. , Dumortier D. , Kenny P. , Maskarenj M. , Pierson C. , Thorseth A. , Xue P. , Knoop M. , Hernández-Andrés J. , Diakite-Kortlever A.
Published: January 2024

This paper introduces SKYSPECTRA, an open-source data package comprising spectral daylight measurements collected from various sources worldwide. The dataset encompasses measurements from both long-term measurement sites and specific periods or experiments. The paper describes the data collection, selection, and organisation process within a standardised framework, ensuring consistency in naming conventions, formats, and units across all datasets. It also describes how the data is structured for operability in programming languages like R or Python for data analysis. SKYSPECTRA aims to facilitate further research and development of daylight applications that leverage spectral sky data by providing a comprehensive and standardised sample spectral daylight dataset that represents geographical locations, seasons, atmospheric conditions, and times of day.
EXPLORATORY STUDY TO DEFINE NEW OBSERVATION GEOMETRIES FOR ROAD LIGHTING DESIGN
Authors: Lebouc L. , Boucher V. , Richard P. , Greffier F. , Nicolaï A.
Published: January 2024

This article focuses on the visibility of road users in urban environment. First, we carried out a virtual reality experiment to find out where we look on the ground when we travel in city. This enabled us to deduce observation angles for each type of user. Measurements on an experimental site and simulations were carried out with these new observation angles. This enabled us to assess the impact of changing the observation geometry on the quality criteria of a lighting installation and on the visibility criterion. We have shown that increasing the observation angle leads to a reduction in the mean luminance but, despite this, visibility is not affected. This led us to propose adaptations to the current recommendations: using a mobile observer for an observation angle greater than 1° and downgrading by one class when dimensioning a lighting installation in the city in the standard way.
A COLOUR FIDELITY MODEL BASED ON HUNT EFFECT
Authors: Ohno Y. , Li J.
Published: January 2024

The perceived chroma of objects decreases at lower light levels, which is known as Hunt Effect. Several recent studies demonstrated that Hunt Effect is effective and significant at the normal indoor light levels, indicating that objects under typical indoor lighting environment are appearing less saturated compared to that under outdoor daylight. According to this principle, the preference for chroma-enhancing lights in indoor lighting may be explained as an effect of colour fidelity under different light levels. To investigate this further, a dynamic colour fidelity model was developed based on a series of vision experiments conducted recently at NIST to quantify the perceived chroma changes by Hunt Effect. The model was evaluated using the spectra of lights used in the past preference experiments, comparing its output with the visual evaluation results. The results showed that the relative colour fidelity curves for light sources of varied chroma increase levels, calculated by the model, agreed well with the visual evaluation on these lights in the experiments.
METROLOGICAL IMPACT OF INTRODUCING CONE FUNDAMENTAL-BASED PHOTOMETRY AS THE BASIS TO DERIVE PHOTOMETRIC UNITS
Authors: Shitomi H.
Published: January 2024

CIE cone-fundamental-based photometry has drawn close attention as a concept to derive scientifically more reliable data to quantify visual sensation. Recently argument has been stirred up about the possibility to adopt a revised spectral luminous efficiency function VF(λ) based on the CIE cone-fundamentals as a standard function to derive photometry quantities, instead of current V(λ) function. While adopting a scientifically more rigorous concept in the SI is quite important, there seems controversy on the idea to replace from V(λ) to VF(λ). Two ways of analysis, in terms of the potential change of photometric values and an instrument quality index, were made to identify the real impact when the standard photometric function V(λ) is replaced with VF(λ). It was found that the potential changes caused by the replacement of the standard photometric function are not negligible in many cases, and explicit discontinuity of the measurement values, that cannot be compensated by modifying the definition of the base SI unit, would be occurred.
POST-OCCUPANCY DERIVED USER PROFILES FOR IMPROVED ENERGETIC AND LIGHT DOSE RELATED BUILDING SIMULATION
Authors: Weninger J. , Hammes S.
Published: January 2024

User behaviour has proven to be a significant influencing factor on key performance indicators of lighting systems, such as energy efficiency or light doses, and values currently achieved in applications offer the risk to deviate significantly from simulation values. Since incorrect assumptions about user behaviour during the simulation process turn out to be primarily responsible for the performance gaps in this context, research on improved user modelling represents a promising approach to achieving environmental policy goals.
In the present work, the authors present a method for a data-driven derivation of a model to predict individual user profiles from post-occupancy data using support vector regression with the restriction to low-level and easy-to-collect input features. The performance of the model was benchmarked against existing assumptions. The results show a significant improvement compared to existing models, even if generalizability of the results could not be achieved due to the insufficient amount of data.
THE NEED FOR STANDARDISATION IN THE MANUFACTURE, CALIBRATION AND USE OF BILIRUBIN RADIOMETERS
Authors: Bergen T. , Lynn M.
Published: January 2024

Jaundice (hyperbilirubinaemia) is a condition in which the skin turns a yellowish colour due to the presence of high levels of bilirubin in the blood. Treatment is usually by phototherapy: exposing the skin to blue-coloured light with a peak wavelength range of 450 nm to 460 nm.
There are two main problems with the calibration and use of the radiometers designed to measure this optical radiation. First, there is no standardised optical radiation source for the treatment, and no standardised spectral responsivity function for the instruments. Second, the instruments themselves often incorrectly display measurements in the units of spectral irradiance (Wcm-2nm-1) rather than broadband irradiance (Wcm-2).
This paper provides a review of the development of the action spectrum used in the treatment of jaundice and outlines the main problems encountered by calibration laboratories and users of the instruments. Good agreement between calibration laboratories when using a controlled source spectrum is demonstrated.
RECONSTRUCTION OF CAMERA SPECTRAL RESPONSIVITY USING MULTIPLE NARROW-BAND LED RADIANCE SOURCES
Authors: Bouroussis C. , Florian S. , Peter B. , Nina B. , Reto S.
Published: January 2024

This paper presents methods for the characterization of monochrome or colour imaging sensors using multiple narrowband colour LED as radiance sources and optimization algorithms in order to estimate their spectral responsivity. This method can be used in cases where a monochromator setup is not available or a fast estimate is needed. In addition, XYZ coordinates for various radiance sources are estimated using the camera counts from the three colour channels (RGB). For this purpose, various linear and non-linear models of RGB values are tested. The RGB models are trained using different groups of reference sources under various sets of weighting factors per source and the corresponding coefficients are calculated via optimization algorithms. The models output and the optimization results were compared to ground truth and expected errors for each of the proposed methods were calculated. This research showed that there could be a good estimate of a camera's spectral responsivity using Legendre polynomials of around 6-8th order and given a multiple LED radiance source. In addition, the estimate of XYZ coordinates using RGB counts can be optimized for specific groups of sources with an expected error even below 1%.
TOWARDS PUBLIC LED LIGHTING WITH MINIMAL IMPACT ON INSECT MOVEMENT
Authors: De Causmaecker L. , Segers L. , Vanschoenwinkel B. , Jacobs V. , Van den Bossche P. , Mentens A.
Published: January 2024

Over the last decades, a decline in insect populations has been observed. Public lighting infrastructure is both expanding to previously unlit areas, and already existing infrastructure is being replaced LED lighting. Consequently, there is a growing imperative to investigate the impact of artificial light at night (ALAN) on nocturnal insect communities. As the correlated colour temperature (CCT) of LEDs is a customisable industry standard, this paper studies its impact on the abundance of attracted nocturnal insects. Data were collected using three LED light sources switching subsequently between 2700K and 6500K, with a similar luminous flux of 6696 lm and 7440 lm, respectively. A vertically positioned white surface gathers attracted insects and facilitates the image-based assessments. Observations during a pilot experiment of four nights in the Belgian Famenne-Ardenne region currently show that the number of attracted insects was 13% higher at 2700K than at 6500K. Broader tests across a wide range of ecosystems and light characteristics will be performed to confirm to which extent these results may be generalized and can inform the development of insect-friendly lighting.
ANALYSIS OF LIGHTING ENERGY CONSUMPTION THROUGH COST-OPTIMAL INVESTMENTS FOR RESIDENCES: A CASE STUDY IN TURKEY
Authors: Kaymaz E. , Manav B.
Published: January 2024

The study represents an approach to improving the annual lighting and primary energy performance of a residential building in temperate-humid and hot-dry Mediterranean climates in Turkey by simulation-based optimization method. In this context, five design variables and sixty four options including façade orientation, window size and configuration, window-to-wall ratio, thermo-physical properties of glazing, and light reflectance value of walls are investigated. The global cost of interior lighting system proposal and passive design strategies are calculated accordingly. Compared to the reference building, we achieved 26.5 - 27.6 % savings in lighting energy, 8.5 - 8.9 % in global costs and 10.5 - 12.4 % in primary energy as well as 9.4 - 10.6 % reduction in carbon emissions for the optimal solutions depending on the climate zone, respectively. Daylight performance of sample living rooms is also evaluated with climate-based daylight modelling (CBDM) metrics for the base case and optimal solutions.
CHARACTERISING HEAD-MOUNTED DISPLAYS BASED ON VISUAL ASSESSMENT
Authors: Lee C. , Ou L.
Published: January 2024

This study used three visual assessment techniques, partition scaling, unique hue judgement and colour matching, to develop a characterisation model for a head-mounted display (HMD) – taking the GOG model as an example in this research. A pilot study was first carried out on an LCD for feasibility test, with 33 observers taking part. This was followed by the main experiment, using the same visual assessment sessions for an HMD, with 24 observers participating. Lastly, a colour appearance experiment was conducted to evaluate the visually-based GOG model for the HMD. The experimental results show good predictive performance, with a CV value of 22.7 for lightness, 33.9 for colourfulness and 5.5 for hue quadrature between the visual results and the predicted values by the visually-based GOG model.
IMPACT OF COLOUR TEMPERATURE AND ILLUMINATION LEVEL ON SAFETY PERCEPTION FOR PARKING GARAGE LIGHTING
Authors: Mentens A. , Jacobs V. , Van den Bossche P. , Scheir G. , Dotreppe G.
Published: January 2024

Lighting conditions in a parking garage are mainly designed for motorized traffic. However, vulnerable road users are often present, and their perception of safety is currently not considered. While luminaires are often replaced by energy-efficient LEDs, this opens possibilities for adjusting illuminance levels and correlated colour temperatures (CCT). For this reason, this study presents a pairwise experiment held in an underground parking garage to identify combinations of vertical illuminance (Ev,v) and CCT with the highest perception of safety.
Preliminary results show that a CCT equal to 3000K and 4000K are preferred over 5000K, with a higher significance at higher Ev,v. This suggests that CCT is less relevant at lower Ev,v. The results also indicate a possible stimulus range bias for Ev,v, and therefore a follow-up study with a different stimulus range is required. Through the observations presented in this study, improved suggestions for parking garages standards can be prepared.
SPECTRAL DEPENDENT NON-LINEARITY OF CHARGE ACCUMULATING PIXEL MATRIX SENSORS
Authors: Schrader C. , Ledig J.
Published: January 2024

The application of camera systems based on charge accumulating sensors for quantita-tive measurements of light distributions requires correction of significant systematic errors like non-linearity. A characteristic type of signal non-linearity that often occurs is a linear decreasing one. This contradicts the assumption of imperfections of the device to be the source of non-linearity but looks like a systematic effect. This work will describe the search for the reason of this type of non-linearity which ends in the observation of a spectral dependence of the non-linearity. A first approach to correct this effect without knowing the source spectrum is presented.
EXPLORING THE RESTORATIVE POTENTIAL OF DAYTIME AND NIGHTTIME SCENERY IN CAMPUS SPACE: PHYSIOLOGICAL, PSYCHOLOGICAL AND BEHAVIOURAL ANALYSIS
Authors: Zeng X. , Lin Y. , Chen S. , Zhang B.
Published: January 2024

Due to various factors including heavy academic workload, social competition, and interpersonal relationships, a growing number of college students are experiencing mental health issues. This study aims to explore the impact of campus lighting environments on college students’ restorative experiences. We assessed physiological, psychological, and behavioural changes in college student participants to evaluate the restorative benefits of the same space under three different lighting conditions: a cloudy daytime scene, night scene A with landscape and street light, and night scene B with only street light. The results from Inter-Beat Interval, reaction speed, and the Perceived Restorative Scale (PRS) indicate that night scene A is evaluated more positively in terms of its restorative benefits compared to the daytime scene. These findings provide practical evidence for the potential restorative effects of nighttime landscapes.
ACCURATE MEASUREMENT OF DRIVERS’ REACTION TIMES IN THREE DIFFERENT ROAD LIGHTING SETTINGS
Authors: Nilsson Tengelin M. , Källberg S. , Lindgren M. , Ebenhag S.
Published: January 2024

This paper presents a study on the measurements the reaction time of a car drivers and how this reaction time is influenced by the road lighting. Three different road lighting settings (two with constant output but different light levels and one modulated) were tested in the city area of the car test track AstaZero. Suddenly appearing targets placed along the track were used to trigger a response to brake. The reaction time was measured by time stamped recordings of the target movement and brake pedal pressure. Release of the gas pedal was also recorded, and time stamped. 40 research persons drove 12 laps each, one driver at the time, where the lighting setting and which target would appear was altered between each lap. Each road lighting setting was selected four times in a randomized order. Preliminary analysis of the reaction time data indicates no influence of the modulated lighting on the reaction time but a slight tendency that the reaction times are increased with a lower light level.
A POWER-EFFICIENT SMART LASER-PHOTOLUMINESCENT-LIGHT (LPL) WITH PV-SYSTEM INTEGRATION: EXPERIMENTAL ANALYSIS AND OPTIMIZATION FOR PEDESTRIAN ROADS
Authors: Belloni E. , Celli I. , Nakamura S. , Pisello A. , Villacci D. , Cotana F.
Published: January 2024

The increasing urbanization and population growth in cities highlight the need for energy-efficient and sustainable lighting solutions. This paper presents a novel approach to the use of laser diodes and photoluminescent pavement to achieve a self-lighting surface. This innovative system, called LPL (Laser Photoluminescent Light), combines a 450 nm blue laser diode with photoluminescent materials that emit light through the absorbance of photons. Two types of self-illuminating surfaces, phosphorescent ceramic tiles and concrete with photoluminescent pigments, were investigated. The experimental analysis focused on energy consumption, illuminance levels, and visual comfort. The photoluminescent pavement shows promising lighting performances, and a questionnaire-based survey indicated positive visual comfort among participants. The integration of a PV system with the LPL further enhances its energy efficiency. This research provides valuable insights into the optimization and implementation of a power-efficient smart lighting solution for pedestrian roads, contributing to the development of sustainable and intelligent urban environments.
ANGULAR DEPENDENCY OF THE LIMITING PHOTOMETRIC DISTANCE
Authors: Dotreppe G. , Scheir G. , Van den Bossche P. , Jacobs V.
Published: January 2024

The limiting photometric distance (LPD) demarcates the boundary between the far-field and near-field regions of a light source, where the validity of the point source approximation and the application of the inverse square law can be upheld. Traditionally, this distance is determined along the optical axis and is considered universally applicable to all emission angles. However, for cos^n-distributed, rotationally symmetric light sources, an angular dependence is observed contingent on the beam width. Beyond a certain angle, the LPD for narrow beam light sources surpasses that along the optical axis in off-axis directions, indicating the invalidity of the point source approximation as defined on-axis. Therefore, an angular range is derived wherein the illuminance can be computed utilising the inverse square law, with errors of 1 % or less compared to exact solutions. This range is defined for square and round emitters based on their full-width at half-maximum angles.
USING A CASE-CONTROL METHOD TO EXPLORE THE IMPACT OF LIGHTING ON CYCLE RATES: INVESTIGATING THE CHOICE OF CASE AND CONTROL TIME PERIODS
Authors: Balela M. , Uttley J. , Yesiltepe D. , Fotios S.
Published: January 2024

Comparing the counts of events occurring at different times of day is one approach to measuring the impact of ambient light level on events such as crime, road traffic collisions and travel flows. We investigated the choice of case and control hours on the outcome of analysis of cyclist flows for two cities, Arlington (VA, USA) and Birmingham (UK). The analyses revealed some differences in the estimated odds ratios. While all combinations tended to show a significant effect, there was some variation in effect size, and that could affect the determination of practical relevance. We suggest that future work presents mean odds ratio from all combinations of case and control hour, weighted by the number of events in the case hour.
LIGHTING EDUCATION: A COMPARISON OF BRAZILIAN AND ITALIAN CONTEXT
Authors: Godoy Daltrozo J. , Tschiedel Martau B. , Lo Verso V. , Pellegrino A.
Published: January 2024

This study aimed to understand, from the perspectives of architects in different countries regarding their education in lighting and its implications for their professional practice. In addition, also observe their shortcomings in order to contribute to a discussion about teaching. Questionnaires were applied to architects from Brazil and Italy and the results revealed differences such as exposure to teaching and educational emphasis and similarities such as recognizing the extreme importance of lighting in architecture and feeling the need for more active methodologies in teaching. Terms such as "practical application", "hands-on experiences" and "field visits" were identified as crucial elements for improving understanding and skills in lighting design in both contexts. The study concludes emphasize the significance of enhancing lighting education within architecture curricula as a means to better equip future architects in shaping and enhancing the human experience within the built environment.
EMULATING DAYLIGHT IN A NEONATAL INTENSIVE CARE UNIT WITH A NOVEL SPECTRALLY TUNABLE LIGHTING SYSTEM
Authors: Cao Y. , Zhang K. , Gruner K. , Greenberg J. , Lang R. , Wang J. , Soler R.
Published: January 2024

Lighting impacts mammalian physiology through wavelength and time-of-day dependent pathways mediated by nonvisual opsins. Some of these pathways affect processes crucial to the outcomes of the neonatal intensive care unit (NICU) patient population, such as growth, metabolism, and retinal vascular development. A lighting system emulating daylight characteristics may benefit this population and facilitate future clinical studies. We introduce the use of a spectrally tuneable lighting system (Spectral Lighting) to emulate daylight within the NICU of a paediatric hospital. Six months of sunlight irradiance data were collected onsite to inform the development of a custom NICU lighting plan. We analysed wavelength composition of this data throughout the day by assessing photon flux (photons/cm2/s) across three wavelength ranges: (1) 380 – 430 nm (violet, opsin 5 absorption), (2) 430 – 530 nm (blue, opsin 3 and 4 absorption), and (3) 630 – 730 nm (red, for spectral balance). Here, we introduce our NICU lighting plan that emulates daylight’s composition and adheres to colour rendering metrics.
WINDOW-VIEW-RECOGNITION BASED ACCEPTABLE DYNAMIC DAYLIGHTING OF RESIDENCE
Authors: Hong L. , Lin Y. , Zhang X. , Ma R.
Published: January 2024

The important role of daylight in residential buildings is widely recognised. However, there is little consensus on the requirements for dynamic daylighting in residences without extensive surveys and daylight measurement. This paper proposes a window-view-recognition-based machine learning model for dynamic daylight prediction, which is able to calculate the annual hourly vertical daylight illuminances at the centre of the window with mean absolute percentage error below 0.6%. The prediction with high accuracy is based on the local climate data, window orientation, and a vertical window view fisheye image, which can be used in extensive surveys. A pilot survey was conducted to collect the window view data and occupants’ subjective evaluation of the residential daylight environment to explore the acceptable dynamic daylighting. The annual average luminous flux at the window plane is significantly correlated with occupants’ evaluations. The workflow for window-view-recognition based acceptable dynamic daylighting of residence is testified to be feasible.
THE EFFECT OF INDOOR LIGHTING ON HUMAN PSYCHOLOGY AND PHYSICAL ACTIVITY DURING COVID-19 LOCKDOWN: A SURVEY
Authors: Zhao C. , Lin Y.
Published: January 2024

Emergency lighting is only used in specific situations, but it is a very important component of a lighting system. Natural disasters and unnatural disasters usually caused large-scale power outage situation. In this emergency situation, the lack of light source brings great distress to the basic physiological needs of the affected people. The coronavirus disease-2019 (COVID-19) related lockdowns provided a good opportunity to obtain comprehensive datasets. Shanghai, China, implemented the strict prevention measures from March to May 2022 due to the outbroken of COVID-19. This study conducted a survey of people in home isolation, including home lighting environment, light exposure behaviour, mood, sleep quality, physical activity and isolation effects, to assess the impact of emergency lighting on human psychology and sleep. The results shown that depression and vigour were positively affected by bright-cool light. However, long-term use of bright white light also delays the sleep onset time during the COVID-related lockdown.
MEASURING DARKNESS FOR SAFE AND SUSTAINABLE EXPERIENCES IN NORTHERN CITIES
Authors: Pihlajaniemi H. , Vuorenmaa R. , Parhankangas O.
Published: January 2024

Besides the many positive values relating to lighting, a wider international understanding is emerging that the amount of lighting and energy consumed must be reduced. In this paper, a case study results of developing a luminance-based method for measuring and analysing the visual-spatial light appearance of scarcely lit urban environments are presented and discussed. In the process, nocturnal urban views were analysed with observations and luminance camera measurements, and essential features for visual-spatial experiences were identified. According to the preliminary results, the chosen visual-spatial concepts – enclosure, open view, interspaces, framing, scale, detailing and user relation – that were tested in creating the analysis images, seem to be useful conceptual tools for framing quantitative analysis of complex luminance images of urban darkness. The results of this study help to develop sustainable and energy-efficient solution models and season dependant lighting design strategies for northern urban environments, respecting the values of darkness.
BCD LUMINANCE ESTIMATION MODEL REFLECTING OPTICAL AND RECEPTIVE FIELD CHARACTERISTICS OF VISION
Authors: Takase K. , Hara N.
Published: January 2024

In the construction of a comfortable visual environment indoor and outdoor, discomfort glare is an essential rating category, and evaluation indices of that such as UGR and DGP are used worldwide for its prediction. Recently, visual environment assessment indicators were developed to model characteristics related to vision. However, the visual characteristics treated in these models are built into the models without sufficient reference to their relevance to glare assessment, and it is questionable whether they should be applied to glare assessment.
In this paper, we propose a Borderline between Comfort and Discomfort (BCD) (Luckiesh, 1949) luminance estimation model that reflects the ocular optical system and the visual nervous system as visual characteristics. The suitability of the model is examined by fitting the model to subjective evaluations obtained from experiments on discomfort glare. For the various visual characteristics estimated by fitting the model, please refer to another paper. (Hara, 2023)
ILLUMINANCE READINGS FROM THIRTEEN SMARTPHONES: MEASUREMENT ACCURACIES AND APPLICABILITY
Authors: Van Duijnhoven J. , Aarts M. , Mardaljevic J.
Published: January 2024

Light fulfils numerous roles in human lives resulting in different lighting needs presented in standards and guidelines. For any lighting design, lighting measurements are crucial for evaluating the installed lighting system. Calibrated photometers are recommended for accurate measurements, although smartphones are sometimes used for indicative measurements. In this study we assessed the measurement accuracies of 13 smartphones. In addition, the wider applicability of smartphones for light measurements in the field is discussed. Our results showed that illuminances measured with smartphones need to be multiplied with an absolute correction factor of 0,63 to 2,54 depending on the smartphone and the illuminance range. Furthermore, although all smartphones showed a good linear response, the directional response was very poor. In conclusion, based on both accuracy and applicability considerations noted in this paper, we strongly discourage the use of smartphones for light measurements to test compliance with standards and guidelines.
RESEARCH ON THE BRIGHTNESS LIMIT OF MEDIA FACADE IN MIXED COMMERCIAL AND RESIDENTIAL STREETS
Authors: Zhang B. , Lin Y. , Zeng X. , Chen S.
Published: January 2024

In order to quantitatively evaluate the impact of display screens on residents living near commercial streets more effectively, this study focuses on two key parameters: the brightness of the display screen and the illuminance at the residents' windows. Theoretical derivations were conducted to establish the mathematical relationship between brightness and illuminance under different positions and angles. The derived formulas were validated through three sets of experiments, and the results indicated that the accuracy of the theoretical derivations increases as the distance (r) between the display screen and the window location increases； The accuracy of the theoretical derivations decreases as the angle (α) between the line (d) connecting the window and the display screen and the normal vector of the screen increases, with α
DYNAMIC LIGHTING CONTROL FOR ENERGY SAVINGS BASED ON JUST NOTICEABLE DIFFERENCE EXPERIMENT FOR MUSEUMS AND RETAIL
Authors: Araiza D.
Published: January 2024

The U.S. Department of Energy estimates that commercial buildings account for 18% of total U.S. energy consumption, of these commercial buildings, retail stores and museums have visitors who occupy the spaces only for short periods of time.
This presents an opportunity to lighting design protocols to reduce energy consumption in museums and retail stores with dynamic controls that adjust the interior lights during periods of vacancy, thereby maximizing energy savings. This objective of this research was to identify possibilities where dimming lights are not noticeable to the eye through a full-scale human subject study based on Just noticeable Different (JND). By conducting a human subject study at full scale, this study found that dimming lights gradually with the implementation of ramp rates can significantly decrease human perception. Participants ability to detect changes when dimming light levels up to 20% using ramp rates tested was of 25% compared to 92% by switching.
OFFICE LIGHTING SMART CONTROLS BASED ON USER REQUIREMENTS
Authors: Campano M. , Acosta I. , Bustamante P. , Domínguez-Amarillo S.
Published: January 2024

Daylight dynamic metrics present an alternative approach for evaluating the energy conservation benefits promoted by lighting control systems. This study aims to quantify the energy savings enabled by lighting smart controls using two novel metrics tested by monitoring a mesh of illuminance-meters in test cells over a one-year period: continuous and overcast daylight autonomy. Three types of controls are proposed, based on switches and dimmers, which can be operated by illuminance meters and irradiance detectors. The energy savings are evaluated based on weather data, room dimensions, internal reflectances, window size, and user requirements —working hours and illuminance needs. The results demonstrate a reduction in average electric lighting energy consumption of up to 23%, indicating the effectiveness of the smart controls proposed. Smart controls without illuminance-meter feedback are only recommended for shallow rooms with low lighting requirements, while dark rooms demand a complex dimming system managed by external illuminance meters
A PILOT TEST OF DAYLIGHTING AND ELECTRIC LIGHTING TO ADDRESS VISUAL AND NON-VISUAL REQUIREMENTS
Authors: Biju P. , Ståhl R. , Gentile N. , Mattsson P.
Published: January 2024

Advancements in understanding the non-visual effects of light have sparked interest in using lighting to promote circadian entrainment. Circadian design metrics like melanopic equivalent daylight illuminance (mEDI) are now being adopted with proposed target values. Traditional lighting design, focused on horizontal illumination for visual needs, falls short for circadian lighting design which should focus on vertical illumination at the eye. Previous research suggests that horizontal illuminance from electric lighting may need to be three times higher than standard lighting design criteria to reach non-visual targets for melanopic illuminance requirements, posing an energy efficiency challenge. This pilot study tests two electric lighting schemes based on spotlights and pendants, combining electric lighting and daylighting. Two identical office mock-ups with the different light distributions were used. An initial assessment of the physical rooms was performed. This included tests with subjects (N = 10) under electric lighting and mixed daylight/electric lighting conditions. Additional (day)lighting scenarios were simulated in LARK 2.0 and the energy use for lighting was calculated. The results show that electric lighting alone could not meet the non-visual targets. Including daylighting significantly decreased the energy use for lighting while maintaining adequate illumination on both horizontal and vertical surfaces. In conclusion, it is highly recommended to incorporate daylighting into the design of lighting for non-visual needs. Failure to do so can lead to over dimensioning of electric lighting, resulting in unnecessary energy use.
IMPLEMENTATION OF A HIGH-SPEED LED CHARACTERISATION SYSTEM
Authors: Poppe A. , Hantos G. , Ender F. , Hegedüs J.
Published: January 2024

The purpose of this paper is to provide an overview on the realization of the concept aimed at high throughput LED testing. The target was to achieve at least one order of magnitude decrease in the overall testing time spent on a single LED package. The main goal of the improved throughput of laboratory testing of LEDs facilitate that Delph4LED-style LED modelling becomes an industrial reality. The second overall objective is to assure, that isothermal IVL characterization of the LED packages being aged becomes a feasible option, thus making it possible to create the elapsed lifetime dependent multi-domain circuit simulation model of LEDs.
RESEARCH ON THE EVALUATION METHOD OF SPATIAL BRIGHTNESS FOR CLASSROOM LIGHTING ENVIRONMENTS
Authors: Liu K. , Cheng M. , Guo P. , Zou N.
Published: January 2024

With the continuous development and improvement of human factors lighting research, while satisfying the functional lighting of indoor spaces, people are pursuing more breakthroughs and innovations in light quality and light health. The evaluation of the quality of the lighting environment gradually expands from the traditional work surface illuminance to the spatial brightness, so as to improve the observer's visual performance and visual perception. Therefore, this research proposed an evaluation method of spatial brightness for classroom lighting environments. Combined with the observer's field of view, the evaluation indicators of spatial brightness are proposed: the spatial brightness index BSI and the spatial brightness contrast BSC. Use BSI and BSC to measure the brightness and the chiaroscuro of the lighting environment respectively. This research can supplement the current lighting environment evaluation system, and has certain reference value to further improve the current test standards and improve the quality of the lighting environment.
USING A LUMINANCE ANALYSER TO MEASURE THE LUMINANCE OF CELESTIAL BODIES DURING ECLIPSES AND OTHER ASTRONOMICAL MEASUREMENTS
Authors: Novák F. , Baxant P. , Motyčka M. , Škoda J.
Published: January 2024

The paper describes the possibilities of using a luminance analyser (ILMD) to measure the luminance of the Sun and Moon. Particular attention is then paid to images acquired during the partial eclipses of these celestial bodies during 2022. The images are evaluated in terms of the luminance distribution on these bodies and the temporal changes that occurred during the measured events. The analysis is performed either in the form of simple luminance maps, by means of slices through the regions of interest, or statistically by means of histograms. The possibilities of using the data thus obtained for simple photometric calculations are also demonstrated.
LED LIGHTING IN ROAD TUNNELS: SIMULATION OF ENERGY-EFFICIENT ADAPTIVE LIGHTING SCENARIOS
Authors: Talon D. , Dumortier D. , Besson S. , Jost S.
Published: January 2024

The control of LED lighting installations through natural lighting conditions, traffic speed, or state of the ground conditions can lead to significant energy savings in road tunnels. A dynamic model has been developed to estimate them. This model can evaluate the need for road luminance levels inside a tunnel in function of the parameters previously mentioned. It can also calculate the actual luminance levels implemented to fulfil this need, and the energy consumptions associated. The model was applied to a test tunnel located in the Paris area, as part of a wider research project. This tunnel receives a heavy traffic and is subject to road congestion for several hours a day. The results showed that annual energy savings around 35% are achievable with a control of the lighting installation through traffic speed, and around 25% with a control through state of the ground conditions (dry or wet road).
REPRODUCTION OF DAYLIT ENVIRONMENT IN WORKSPACES USING LED LIGHTING: VERIFICATION OF THE INFLUENCE OF VIEW FROM A WINDOW
Authors: Akuzawa Y. , Xiang L. , Yoshizawa N. , Nakaso M. , Kaiho K. , Shinohara N. , Oe Y.
Published: January 2024

This study aimed to determine whether it is possible to obtain the same effect of a daylit environment by reproducing daylighting using LED lighting in workspaces. This paper focused on the element “view” of the daylit environment. Two types of experiments were conducted in an experimental space to assess the influence of viewing through a window. Psychological evaluations and physiological responses were compared between with-view (daylighting) and without-view (reproduction of daylighting with LED lighting) conditions at each illuminance level at eye level. The results demonstrated that the with-view condition was psychologically positive (openness and relief) and physiologically stress-less at 120 lx, whereas the without-view condition was evaluated as easier to concentrate on and stress-less at 600 lx. Therefore, considering general lighting intensity when working, a sufficient effect may be obtained in workspaces without view by reproducing daylit environments using LED lighting.
VIEW EVALUATION INDEX USING VISIBLE VOLUME IN OFFICE BUILDINGS
Authors: Arano K. , Ohki C. , Oe Y. , Munakata J. , Kato M. , Yoshizawa N. , Miyake H.
Published: January 2024

Windows are essential from a psychological perspective, as they are a source of visual stimulation and contribute to relaxation and refreshments. Several accumulated findings clarify the effects of view quality, but there are currently no corresponding solid quantitative indices. This study aimed to focus on a physical quantity called ‘visible volume,’ which contained information comprising view content and access in office buildings, and to verify this by analyzing the relationship with the view evaluation obtained through subjective experiments. The results showed that the quality of the view, such as satisfaction with the view, could be assessed by the 'total visible volume,’ which considered 'distance to each view element' in addition to the 'solid angle of the window.’
A NEW BRDF MODEL FOR IN-SITU OPTICAL AND THERMICAL MATERIAL CHARACTERIZATION
Authors: Bouillot E. , Legrand B. , Labayrade R.
Published: January 2024

The optical and thermal characterization of materials (i.e. radiometric characterization in the visible and infrared ranges) is an important way to reduce energy consumption in buildings. Characterizing the properties of building surfaces in situ prior to rehabilitation will make possible the selection of rehabilitation materials that achieve the best compromise between summer and winter comfort, while significantly reducing energy consumption.
In this paper, we present a new data driven BRDF model with two parts: a diffuse part and a specular part. Most of literature BRDF models have a constant diffuse part; in this paper we propose a model with a variable diffuse part to better fit measured data. The specular part is derived from the Ward model.
We compare our model result to others from literature and show it presents better accuracy especially thanks to our diffuse part.
CAUSAL CONNECTION BETWEEN PSYCHOLOGICAL VIEW AND DAYLIGHTING EVALUATION IN LIVING SPACES
Authors: Budoh Y. , Sasaki S. , Oe Y. , Kishimoto N. , Taniguchi K. , Yoshizawa N.
Published: January 2024

Currently, there is renewed focus on the importance of views in evaluating window performance. In addition, previous studies have shown that the amount of daylight perceived by people may be influenced by the view rather than the actual amount of light, however, the relationship between them has not yet been clarified and needs to be examined. In this study, evaluations on window view and daylight were extracted from a questionnaire survey on environmental adjustment behaviour in housing, which was conducted in the Kanto region of Japan, and their psychological relationships were examined. The results of the analysis showed that the evaluation of daylighting was infected to some extent by evaluating the view at the window. This indicated that the evaluation of the view at the window can serve as a basis for evaluating the visual environment through windows.
MEASURING THE VISUAL ENVIRONMENT OF CHILDREN AND YOUNG PEOPLE AT RISK OF MYOPIA: A SCOPING REVIEW – INITIAL FINDINGS
Authors: Dahlmann-Noor A. , Khazova M. , Price L. , Bokre D.
Published: January 2024

Myopia (short-sightedness) is an emerging priority eye disease. Rise in prevalence and severity are driven by changes in lifestyle and environment of children and young people (CYP), including less time spent in bright daylight and more time spent on near-vision activities. We aimed to systematically map the literature describing direct, objective measurements of the visual environment of CYP.
We developed an Ovid Medline search strategy, run on 13/07/2022. We included primary research written in English on environmental/behavioural factors and myopia onset/progression in CYP 3-18 years. Two reviewers independently screened titles/abstracts/full texts.
We included 23 articles: 14 explored the association of indoor and/or outdoor light exposure and myopia, three near-vision activities, three both light and near-work, and three time outdoors without illuminance measurements. Most measurements were carried out at the level of individual children, rather than the surrounding environment alone.
Despite limitations in measurement techniques, there is evidence that reduced illuminance, less time spent in bright light and increased daily duration/sustained episodes of near-vision activities and reduced working distance are associated with increased myopia prevalence/progression.
A STUDY OF THE EFFECTS OF ARTIFICIAL LIGHTING COLOURS ON OCCUPANTS' SPATIAL PERCEPTION AND CARDIAC RESPONSES
Authors: Dai S. , Wang T. , Hao L. , Li J.
Published: January 2024

Lighting in living environment has a non-negligible impact on psychology and physiology of occupants. In the study, the real-time effects of artificial lighting color of red, yellow, blue, green and white in living room space on human spatial perception and physiological indexes related to cardiac response were investigated. The atmosphere perception was measured with semantic difference scale. And an electrocardiogram (ECG) event recorder were used to monitor the effect of light color on human heart rate and heart rate variability (HRV). The results of data analysis showed that lighting color had a significant effect on space perception indicators, such as warm/cool, casual/formal, and open/closed, and so on. However, no significant effect of light color on average heart rate and HRV related indexes was found.
VALIDATION THE EFFECTIVENESS OF MINDFULNESS CONTENT WITH LED PANEL LIGHT FOR HOME
Authors: Fujiwara Y. , Ikebuchi M. , Tanaka T.
Published: January 2024

Mindfulness refers to a method of observing oneself as one is, by focusing one's attention on the present moment through meditation. In a modern society where one’s brain is flooded with information that needs to be processed, it is important for one to practice mindfulness in daily life. However, for beginners, practicing mindfulness meditation can be difficult. Even if it is practiced, effects may not be realized, which can lead to a lack of motivation to continue. Therefore, we propose an environment where mindfulness meditation can be easily practiced at home by using a controllable LED panel light. The effect of continuous use of the light was subjectively tested with 26 subjects. The light was installed in each subject's home. The experimental environment with the light is easier to practice the meditation than that, which is a static lighting with 37.8 lx and 2700 K.