Papers by Iason Konstantzos
Building and Environment
Global aging strains health infrastructure • Experts identify facets of smart, healthy built envi... more Global aging strains health infrastructure • Experts identify facets of smart, healthy built environments for older adults • IEQ and smart building technologies are contextualized for older adults and caregivers • Challenges for implementation and gaps in knowledge are identified
Bookmarks Related papers MentionsView impact
183rd Meeting of the Acoustical Society of America
Bookmarks Related papers MentionsView impact
arXiv (Cornell University), Oct 30, 2022
Bookmarks Related papers MentionsView impact
LEUKOS
Bookmarks Related papers MentionsView impact
This study introduces a new control framework, based on a low-cost programmable luminance acquisi... more This study introduces a new control framework, based on a low-cost programmable luminance acquisition (HDR) sensor placed on the interior surface of the window. The new sensor, photometrically and geometrically calibrated, can capture luminance and geometry details of potential glare sources within its entire visual span in real time, while also providing feedback about transmitted illuminance. Real-time processing of the sensor data enables an alternate, low-cost glare sensing system that can be directly used in daylighting controls and building automation systems. This novel framework is the first proposed solution to address direct and reflective glare in a straightforward and efficient way and therefore it is a significant step towards improving the visual environment in perimeter building zones.
Bookmarks Related papers MentionsView impact
Optimal positioning of workstations in perimeter offices is a key factor affecting visual comfort... more Optimal positioning of workstations in perimeter offices is a key factor affecting visual comfort and satisfaction, depending on facade design and control. Visual comfort is related to different factors, such as daylight glare and light adequacy. In addition, connection to the outdoors, delivered through window views, is related to the amount of view as well as view clarity. This study presents a new approach to evaluate office workplaces in terms of overall visual environment. Visual comfort, daylight provision and outside view are used as the three basic criteria. A new index, the Effective Outside View (EOV), is introduced to characterize the connection to the outdoors considering the amount and clarity of outside view. In addition, the Visual Comfort Autonomy (VCA) is defined as the portion of time when visual comfort criteria, based on vertical illuminance on the eye, are satisfied. The spatial variation of these indices and continuous daylight autonomy are used to evaluate per...
Bookmarks Related papers MentionsView impact
Visual comfort is one of the main priorities in designing working and living environments. Severa... more Visual comfort is one of the main priorities in designing working and living environments. Several indicators have been developed to quantify the degree of visual discomfort; however, there is a lack of studies in spaces with roller shades on the windows, commonly used in North America. Roller shades transmit direct and diffuse daylight and therefore their effect on visual comfort is complex. A recent study with human subjects proposed two alternative approaches in quantifying visual discomfort for the case of roller shades, based on (i) a modification of the Daylight Glare Probability (DGP) and (ii) an index based on the direct and the total portion of vertical illuminance on the eye of the observer. This paper uses a methodology based on the newly developed indices in an inverse way in order to propose suitable ranges for optical properties of the shade fabrics, in terms of openness factor and visible transmittance. A complex fenestration model that calculates the angular beam–bea...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Konstantzos, Iason. Ph.D., Purdue University, December 2016. A Human-Centered Approach for the De... more Konstantzos, Iason. Ph.D., Purdue University, December 2016. A Human-Centered Approach for the Design of Perimeter Office Spaces Based on Visual Environment Criteria. Major Professor: Athanasios Tzempelikos. With perimeter office spaces with large glazing facades being an indisputable trend in modern architecture, human comfort has been in the scope of Building science; the necessity to improve occupants’ satisfaction, along with maintaining sustainability has become apparent, as productivity and even the well-being of occupants are connected with maintaining a pleasant environment in the interior. While thermal comfort has been extensively studied, the satisfaction with the visual environment has still aspects that are either inadequately explained, or even entirely absent from literature. This Thesis investigated most aspects of the visual environment, including visual comfort, lighting energy performance through the utilization of daylight and connection to the outdoors, using ex...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Shading fabrics have the ability to reduce daylight glare and provide privacy when needed. Recent... more Shading fabrics have the ability to reduce daylight glare and provide privacy when needed. Recent studies have shown that glare indices such as DGP and its simplified version can be used to predict daylight glare through shades when the sun is not within the field of view. However, there are no comprehensive studies on glare sensation with the sun visible through the fabric – a situation that happens in office buildings – and therefore the applicability of glare indices for such conditions is uncertain. Shades with very low openness factors transmit only a small amount of direct sunlight due to their weave density; nevertheless, existing glare metrics may show intolerable conditions for these cases, while specific studies with human subjects are nearly non-existent. This paper presents an experimental study on daylight glare evaluation for the case of shading fabrics with the sun within the field of view. 41 human subjects (n=41) were tested while performing specific office activiti...
Bookmarks Related papers MentionsView impact
Buildings, 2021
The varying indoor environments among educational buildings can have an impact on students’ abili... more The varying indoor environments among educational buildings can have an impact on students’ ability to learn. This study looks at field data from 220 classrooms in the Midwest, United States, over a two-year period, to analyze the effects of the visual environment on student achievement. The visual environmental metrics considered within this scope include the three new view metrics introduced within the EN 17037 “Daylight of Buildings” standard (Horizontal Sight Angle, Outside Distance of View, and Number of View Layers), as well as standard daylight and electric lighting metrics, focusing on light availability and glare. To capture student achievement, math and reading achievement scores were used, accompanied by auxiliary demographic variables. This allowed for a correlational analysis using multivariate regression. Among the notable results of this study, there was a positive effect of the availability of view on reading achievement. However, another view metric, Horizontal Sigh...
Bookmarks Related papers MentionsView impact
Building and Environment, 2021
Abstract Current discomfort glare prediction metrics usually account for at least one of the two ... more Abstract Current discomfort glare prediction metrics usually account for at least one of the two categories of effects that induce discomfort glare – the saturation and contrast effects. Saturation-driven metrics (overall illuminance on the eye) are suited for brightly lit scenes in general. On the contrary, contrast-driven metrics (luminance ratio in the field of view) usually perform better in high contrast conditions such as with small-sized bright glare sources. Only a few existing metrics consider both effects, such as the Daylight Glare Probability (DGP). However, even these “hybrid” metrics may underperform in conditions other than those considered when they were developed, such as in dim scenes with high contrast glare. This paper investigates the ability of current glare indicators to predict perceived discomfort glare in user-evaluated scenes depending on two different adaptation levels. Towards this end, we used a composite dataset of six laboratory studies performed previously and separately in various parts of the world. According to Receiver Operator Characteristics (ROC) findings and complementary statistical research, the hybrid metrics DGP and Eccologit perform best in both investigated ranges (dimmer and brighter scenes). For the single-effect metrics, the contrast-driven metrics appear to perform better than saturation-driven metrics in lower adaptation levels (dimmer scenes), while the reverse is seen in higher adaptation levels (brighter scenes). As a result, metrics that only consider one effect should be used with caution. Although hybrid metrics continue to perform well in the investigated scenes, further research is needed to extend their applicability to a larger variety of lighting conditions that may be observed in work environments.
Bookmarks Related papers MentionsView impact
Energy and Buildings, 2020
Bookmarks Related papers MentionsView impact
Building and Environment, 2020
Bookmarks Related papers MentionsView impact
Science and Technology for the Built Environment, 2018
Bookmarks Related papers MentionsView impact
Journal of Physics: Conference Series, 2019
This study presents the development of a window-attached, low-cost fisheye-stereo camera sensor s... more This study presents the development of a window-attached, low-cost fisheye-stereo camera sensor system for reliable daylighting controls in buildings. The stereovision sensor composed of two cameras can measure 3-D position and luminance of any exterior bright sources after photometric and geometric calibration. Also, by applying a neutral density sensor on one of the cameras and substituting the overflown pixels of the luminance map, a complete luminance map with a wide dynamic range can be retrieved. The new sensor exhibited promising results in validation of 3-D positioning and luminance acquisition, and can be used for real-time glare source detection, location and intensity measurements.
Bookmarks Related papers MentionsView impact
Journal of Physics: Conference Series, 2019
The purpose of design standards and guidelines is to ensure occupant safety and aid in occupant w... more The purpose of design standards and guidelines is to ensure occupant safety and aid in occupant well-being and satisfaction. Educational buildings such as schools should extend this aim, by also promoting student learning, something that has triggered literature in the past suggesting significant correlation between learning performance and the indoor environment. EN 17037 “Daylight for Buildings” is a recently approved European standard that seeks to assess and ensure successful daylit spaces, including sections on protection against glare, exposure to sunlight, and view out. EN 17037 includes three ways of assessing view out in buildings including, Horizontal sight angle, Outside distance of the view, and Number of view layers outside of windows, a combination that potentially makes it an efficient way to describe such a complex concept. This paper will use a large data set of 220 K-12 classrooms in the Midwest region of the United States in order to evaluate whether any of these ...
Bookmarks Related papers MentionsView impact
Lighting Research & Technology, 2019
This study evaluates the performance and robustness of 22 established and newly proposed glare pr... more This study evaluates the performance and robustness of 22 established and newly proposed glare prediction metrics. Experimental datasets of daylight-dominated workplaces in office-like test rooms were collected from studies by seven research groups in six different locations (Argentina, Denmark, Germany, Israel, Japan and the United States). The variability in experimental setups, locations and research teams allowed reliable evaluation of the performance and robustness of glare metrics for daylight-dominated workplaces. Independent statistical methods were applied to individual datasets and also to one combined dataset to evaluate the performance and robustness of the 22 glare metrics. As performance and robustness are not established in literature, we defined performance as: (1) the ability of the metric value to describe the glare scale (evaluated by Spearman rank correlation), and (2) the ability of the metric to distinguish between disturbing and non-disturbing situations (eval...
Bookmarks Related papers MentionsView impact
Uploads
Papers by Iason Konstantzos