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Person: Mehlika Inanici

Measuring Circadian Lighting through High Dynamic Range Photography

Jung, B.; Inanici, M. (2019). Measuring Circadian Lighting through High Dynamic Range Photography. Lighting Research & Technology, 51(5), 742 – 763.

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Abstract

The human ocular system functions in a dual manner. While the most well-known function is to facilitate vision, a growing body of research demonstrates its role in resetting the internal body clock to synchronize with the 24-hour daily cycle. Most research on circadian rhythms is performed in controlled laboratory environments. Little is known about the variability of circadian light within the built and natural environments. Currently, very few specialized devices measure the circadian light, and they are not accessible to many researchers and practitioners. In this paper, tristimulus colour calibration procedures for high dynamic range photography are developed to measure circadian lighting. Camera colour accuracy is evaluated through CIE trichromatic (XYZ) measurements; and the results demonstrate a strong linear relationship between the camera recordings and a scientific-grade colorimeter. Therefore, it is possible to correct for the colour aberrations and use high dynamic range photographs to measure both photopic and circadian lighting values. Spectrophotometric measurements are collected to validate the methodology. Results demonstrate that measurements from high dynamic range photographs can correspond to the physical quantity of circadian luminance with reasonable precision and repeatability. Circadian data collected in built environments can be utilized to study the impact of design decisions on human circadian entrainment and to create guidelines and metrics for designing circadian friendly environments.

Keywords

Physical Constants; Medical Photography; Photography; Built Environment; Morningness-eveningness Questionnaire; Statistical Reliability; Circadian Rhythms; Action Spectrum; Ganglion-cells; Bright Light; Exposure; Sensitivity; Framework; Daylight; Daytime; Model; Rod

Deep Neural Network Approach for Annual Luminance Simulations

Liu, Yue; Colburn, Alex; Inanici, Mehlika. (2020). Deep Neural Network Approach for Annual Luminance Simulations. Journal Of Building Performance Simulation, 13(5), 532 – 554.

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Abstract

Annual luminance maps provide meaningful evaluations for occupants' visual comfort and perception. This paper presents a novel data-driven approach for predicting annual luminance maps from a limited number of point-in-time high-dynamic-range imagery by utilizing a deep neural network. A sensitivity analysis is performed to develop guidelines for determining the minimum and optimum data collection periods for generating accurate maps. The proposed model can faithfully predict high-quality annual panoramic luminance maps from one of the three options within 30 min training time: (i) point-in-time luminance imagery spanning 5% of the year, when evenly distributed during daylight hours, (ii) one-month hourly imagery generated during daylight hours around the equinoxes; or (iii) 9 days of hourly data collected around the spring equinox, summer and winter solstices (2.5% of the year) all suffice to predict the luminance maps for the rest of the year. The DNN predicted high-quality panoramas are validated against Radiance renderings.

Keywords

Scattering Distribution-functions; Daylight Performance; Glare; Model; Prediction; Daylighting Simulation; Luminance Maps; Machine Learning; Neural Networks; Hdr Imagery; Panoramic View

Human-Centric Lighting Performance of Shading Panels in Architecture: A Benchmarking Study with Lab Scale Physical Models Under Real Skies

Parsaee, Mojtaba; Demers, Claude M. H.; Lalonde, Jean-francois; Potvin, Andre; Inanici, Mehlika; Hebert, Marc. (2020). Human-Centric Lighting Performance of Shading Panels in Architecture: A Benchmarking Study with Lab Scale Physical Models Under Real Skies. Solar Energy, 204, 354 – 368.

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Abstract

This study investigates shading panels' (SPs) impacts on daylighting features in a lab scale model in terms of parameters representing potential human eyes' biological responses identified as image forming (IF) and non-image forming (NIF). IF responses enable vision and NIF responses regulate internal body clocks known as circadian clocks. Human-centric lighting evaluates photopic units, representing IF responses, and melanopic units representing NIF responses, combined with correlated color temperature (CCT) of light for potential biological effects. SPs' impacts on such parameters of daylighting have not yet been studied. Previous research mostly studied panels' impacts on visual comfort and glare related to IF responses. This research explores the impact of SPs' color, reflectance, orientation, and openness on photopic and melanopic units and CCT of daylighting inside a 1:50 physical scale model of a space. Approximately 40 prototypes of SPs were evaluated. An experimental setup was designed under outdoor daylighting conditions to capture high dynamic range (HDR) images inside the model. HDR images were post processed to calculate and render the distribution of photopic and melanopic units, melanopic/photopic (M/P) ratios and CCTs in the captured viewpoint of the model. Results reveal the behavior of SPs' color, reflectance, orientation, and openness in modifying daylighting parameters related to biological responses. Bluish panels, in particular, increase daylighting melanopic units and CCTs whereas reddish panels increase photopic units and reduce CCTs. The research results were discussed to provide an outline for future developments of panels to adapt daylighting to occupants' IF and NIF responses.

Keywords

Models & Modelmaking; Shades & Shadows; Daylighting; Color Temperature; Benchmarking (management); Ecological Houses; Eye Tracking; Circadian Rhythms; Adaptive Design; Healthy Lighting; High Performance Façade; Photobiology; Responsive Building; Design; Sensitivity; Illuminance; Systems; Spaces; Impact; Glare; High Performance Facade; Reflectance; Scale Models; Biological Effects; Human Performance; Prototypes; Parameter Modification; Lighting; Shading; Eye (anatomy); Color; Parameter Identification; Light Effects; Panels; Mathematical Models; Images; Biological Clocks; Orientation

Syncing with the Sky: Daylight-Driven Circadian Lighting Design

Altenberg Vaz, Nathan; Inanici, Mehlika. (2021). Syncing with the Sky: Daylight-Driven Circadian Lighting Design. Leukos, 17(3), 291 – 309.

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Abstract

The use of daylight in the built environment is often preferred to artificial light sources as its successful application can provide visual comfort and satisfaction along with the potential for significant energy savings. Exposure to daylight is also the primary source for stimulus that establishes a healthy day/night cycle in all living organisms. This is known as circadian rhythm. Newly discovered photoreceptors (intrinsically photosensitive retinal ganglion cells - ipRGC) within the mammalian eye, including humans, are specifically linked to the portion of the brain responsible for maintaining a healthy circadian rhythm. This discovery has led to a new subject area in the field of lighting design focused on controlling the spectrum of light that these photoreceptors are sensitive to. Currently, work in the field of circadian lighting design is concentrated on the use of artificial light sources for circadian stimulus. This is largely due to the advent of the widespread use of LED technology, which has proven that it can be a significant source of light that can delay or advance the circadian clock. The use of daylight to provide circadian stimulus has been a given in this field of design, however, there has not been very much research into how the built environment affects our ability to effectively receive this stimulus from daylight. In this research, the groundwork is established to start to create a set of guidelines to help architects and designers maximize the potential for daylight to provide circadian stimulus at the earliest stages of a project. This is accomplished through a series of lighting simulations that explore and test various architectural parameters that affect daylight-driven circadian lighting, with simultaneous consideration given to photopic lighting availability and visual comfort. The architectural parameters tested in this study included window head height, building orientation, shading devices, visual obstructions to the sky, and room depth. The results show that informed design decisions could maximize circadian potential in a given space, while achieving visually satisfactory luminous environments.

Keywords

Action Spectrum; Melanopsin; Environments; Sensitivity; Framework; Stimulus; Rod; Circadian Lighting; Daylight; Lighting Simulation; Alfa

Biophilic Photobiological Adaptive Envelopes for Sub-Arctic Buildings: Exploring Impacts of Window Sizes and Shading Panels’ Color, Reflectance, and Configuration

Parsaee, Mojtaba; Demers, Claude M. H.; Potvin, Andre; Lalonde, Jean-Francois; Inanici, Mehlika; Hebert, Marc. (2021). Biophilic Photobiological Adaptive Envelopes for Sub-Arctic Buildings: Exploring Impacts of Window Sizes and Shading Panels’ Color, Reflectance, and Configuration. Solar Energy, 220, 802 – 827.

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Abstract

Northern building envelopes must provide efficient indoor-outdoor connections based on photobiologicalpsychological needs of occupants for positive relationships with the sub-Arctic nature, particularly daylighting and day/night cycles. Envelope configurations of Northern Canada's buildings have not yet considered such requirements. Potentials of adaptive systems are also still limited. This research develops a fundamental model of adaptive multi-skin envelopes for sub-Arctic buildings based on main biophilic and photobiological indicators which characterize efficient indoor-outdoor connections. Biophilic indicators characterize the state of connections among occupants and outdoors which could stimulate biological-psychological responses. Photobiological indicators determine human-centric lighting adaptation scenarios for hourly lighting qualities and sufficient darkness in relation to local day/night cycles and daylighting. Biophilic performance of the proposed envelope was evaluated through 18 numerical models in terms of impacts of window and shading sizes on occupants' field of views. Photobiological lighting performance was evaluated by experimental methods using 23 physical models at 1:10 scale. Surface characteristics of dynamic shading panels, including color, reflectance, orientation, and inclination, were studied for potential photobiological impacts in terms of melanopic/photopic ratios and color temperatures. Results show that the proposed envelope could (i) offer acceptable direct visual connections with the outdoor nature through efficient window sizes for biophilia, and (ii) modify daylighting qualities to address hourly/seasonal photobiological needs of sub-Arctic occupants. Challenges of the proposed envelope to implement under sub-Arctic climatic conditions are underlined especially in terms of energy issues. The research outcomes help architects and decision-makers to improve occupants' wellbeing and healthy buildings in subArctic climates.

Keywords

Window Shades; Building Envelopes; Reflectance; Color Temperature; Daylighting; Building-integrated Photovoltaic Systems; Daylight; Outdoor Living Spaces; Canada; Adaptive Envelope; Arctic Climate; Biophilic Design; Healthy Building; Photobiological Lighting; Light; Exposure; Stress; Design; Architecture; Sensitivity; Illuminance; Environment; Melatonin; Recovery; Surface Properties; Performance Evaluation; Indicators; Polar Environments; Lighting; Shading; Darkness; Decision Making; Envelopes; Configurations; Buildings; Color; Adaptive Systems; Climatic Conditions; Numerical Models; Mathematical Models; Panels; Night; Climate; Orientation; Arctic Region

PhD in the Built Environment

The College of Built Environments consists of five departments that together provide one of the country’s few comprehensive built environment programs within one academic unit: Architecture, Construction Management, Landscape Architecture, Real Estate, and Urban Design and Planning. Together, this combination of departments enable faculty and students to engage almost the entire development process, from economic and environmental planning, real estate, regulatory processes, siting and design, through actual financing and construction, to facility management and adaptive reuse in subsequent stages. Thus, the college is inherently multi-disciplinary, not only in terms of the dimensions of reality that it treats, but also in regard to the specialized disciplines, methods, and practices that it employs: history, theory, cultural criticism, engineering, design, planning, urban design, energy sciences, acoustics, lighting, environmental psychology, ecology, real estate analysis, statistics, management, horticulture, soil science, law, public policy, and ethics. In addition, because of the College’s focus on comprehensive analysis and practice concerning the built environment and its interrelation with society, it is substantially engaged in interdisciplinary work with other units on campus and outside of the campus, including mechanical, civil, and electrical engineering; with public policy and the health sciences; with art and art history; with textual interpretation in the humanities; with many of the computing and digitization activities that range from digital arts to the information school and technical communications; with education and social studies and services; with sustainability and ecological programs, including urban ecology, geography, the College of Forest Resources (especially urban horticulture and urban forestry), and Ocean Science and Fisheries; with environmental and land use law.

The College’s interdisciplinary character is a good fit with the emerging trends in today’s complex world, where only a pluralistic and collaborative approach will generate the necessary learning and teaching, research, and service. If we are to provide, in the end, both disciplinary and professional means to promote environmental well-being, the diverse environmental specializations must be fully integrated. Thus, working outside traditional disciplinary and departmental categories, the College’s faculty will advance solutions to problems that demand interdisciplinary perspectives and expertise. Other UW units bring much to bear on the built environment and students are wholeheartedly encouraged to explore possible cross-campus connections both in obvious and seemingly unlikely places. The Technology and Project Design/Delivery specialization especially connects with Psychology, the Information School, Technical Communication, Computer Science and Engineering, and Industrial Engineering; the Sustainable Systems and Prototypes field with Civil Engineering, Electrical Engineering, Industrial Engineering, Mechanical Engineering, the Information School, Technical Communication, the College of Forest Resources (especially Eco-System Science and Conservation, Urban Horticulture and Urban Forestry), the Evans School of Public Affairs, Geography, Public Health, Ocean Science and Fisheries, and Social Work, Urban Ecology, and perhaps Advanced Materials and Manufacturing Processes and Nanotechnology; the area of History, Theory, and Representation with Textual Studies, Art History, Interdisciplinary Arts & Sciences at Tacoma, and Comparative History of Ideas.

Circular City + Living Systems Lab

The Circular City + Living Systems Lab (CCLS) is an interdisciplinary group of faculty and students applying principles of research and design to investigate transformative strategies for future cities that are adaptive and resilient while facing climate change. 

Synthesizing expertise from architecture, landscape architecture, engineering, planning, biology, and ecology, the Lab’s innovative research spans core topics such as the integration of living systems in the built environment to produce and circulate resources within the food-water-energy nexus, and spatial design responses to COVID-19. 

Ongoing work at the CCLS includes research on urban integration of aquaponics, urban and building-integrated agriculture, circular economies in the food industry, algae production, and green roof performance.

Mehlika Inanici

Mehlika Inanici, Ph.D. is a Professor and the former director of the Design technology track of the Master of Science in Architecture program at the University of Washington, Department of Architecture.

The focus of her research is computational lighting design and analysis. The underlying presumption in her research and teaching is that analytical approaches employed throughout the design processes help architects envision the performance of their designs, accelerate and improve design decisions, and reduce the uncertainty of the outcome. A large body of her research centers on developing and utilizing computer-based (day)lighting analysis techniques and metrics that can facilitate occupant comfort, satisfaction, health, and productivity improvements, in conjunction with significant energy savings.

Inanici has authored or co-authored highly influential papers on the use of high dynamic range (HDR) photography to measure and evaluate existing environments and to conduct psychophysical studies on visual comfort and preference. Her work on lighting measurements with HDR photography was selected as one of the “25 classic papers” in the 50-year history of the Journal of Lighting Research and Technology (2018) among the 2048 papers published between 1969 to 2018. Some of her papers are on the most cited list in Leukos (the journal of Illuminating Engineering Society) and Lighting Research and Technology.

She developed Lark Multispectral Lighting tool in collaboration with ZGF Architects LLC. Lark is an open-source software to simulate the non-visual effects of light that entrains the human circadian system. She also co-developed hdrscope in collaboration with Viswanathan Kumaragurubaran.
Her research has been funded by the US Department of Energy, the Pacific Northwest National Laboratory, the University of Washington Royalty Research Fund, UW Built Environments Innovations Collaborative Grant, and the Nuckolls Funding for Lighting Education.

Prof. Inanici’s teaching focuses on graduate-level courses on building performance simulation (Arch 524 Design Technology V, Arch 582 Computational Lighting Research, and 598 Performance-Driven Design) and research methodologies. She supervises students from the Master of Architecture, Master of Science in Architecture, and the Ph.D. program in Built Environments.

Inanici has received her Ph.D. degree from the University of Michigan. She has Master of Science degrees both in Architecture (University of Michigan) and Building Science (METU), and a Bachelor of Architecture degree (METU). Previously, she worked at the Lawrence Berkeley National Laboratory in Berkeley California. Dr. Inanici is a member of the Illuminating Engineering Society, the International Commission on Illumination, and the International Building Performance Simulation Association.