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Peer Reviewed

Evaluation of the effect of landscape distance seen in window views on visual satisfaction

Indoor Environmental Quality (IEQ) (2020)

Daylighting standards dictate that the view seen through a window can be evaluated using several criteria. Among one of them is the distance at which the visual content can be seen. However, not enough guidance is given on how this criterion can be applied in practice. We used two approaches to address this problem: online surveys and human subject assessment in a controlled experiment using an artificial window. Images were used in both cases to represent window views. Two independent groups of participants took part in either study and both gave subjective satisfaction ratings to three parameters, namely, connection to the outside, visual content and visual privacy. Eighteen images were evaluated in the online surveys by a total of 91 participants while eight images were rated by 50 participants that took part in the controlled experiment. We developed a calculation method, named the Observer Landscape Distance (OLD), to quantify the distance of the window view landscape from the occupant. Our initial results showed that people are more satisfied when features are far away. However, we also showed that when the landscape contained nature, the effect of distance was smaller. If far away views cannot be provided due to site constrains, nature (e.g. trees) should be integrated nearby to increase satisfaction. Current daylighting standards promote distant views regardless of its visual content (nature or urban). We found that visual content matters and occupants prefer urban features to be viewed from a distance, whereas this same recommendation does not apply for nature.

Cover page: Evaluation of the effect of landscape distance seen in window views on visual satisfaction

Creative Commons 'BY-NC-SA' version 4.0 license

Article
Peer Reviewed

An Examination of Range Effects When Evaluating Discomfort Due to Glare in Singaporean Buildings

Indoor Environmental Quality (IEQ) (2021)

This article discusses ratings of visual discomfort from glare across different buildings located in Singapore. These data were used to determine if range effects influence the vertical illuminance values for the same ratings of visual discomfort when the category rating procedure is used. The effect occurs when maxima and minima vertical illuminance (i.e. the range) vary across buildings. Our analyses showed that with a higher vertical illuminance range in a building, the mean vertical illuminance value for the same criterion of visual discomfort also increased. The results suggest that the effect caused by different ranges of measured vertical illuminance present across the buildings biased the ratings of visual discomfort. Although these effects may be unavoidable in some buildings that have vastly different levels of light, the data suggest that the overall range of vertical illuminance must be carefully evaluated when predicting visual discomfort. Matching these conditions may enable vertical illuminance to provide more reliable evaluations of discomfort due to glare.

Cover page: An Examination of Range Effects When Evaluating Discomfort Due to Glare in Singaporean Buildings

Article
Peer Reviewed

The Development of the PKX Myxosporean, the Causative Agent of Proliferative Kidney Disease, in Rainbow Trout Salmo gairdneri Richardson

Kent, Michael L.

Research Theses and Dissertations (1985)

The endogenous development of PKX, the causative agent of proliferative kidney disease, is described in rainbow trout, Salmo gairdneri, by light and electron microscopy. Parasites multiplied by endogeny, binary fission and possibly plasmotomy in the renal interstitium, and elicited an interstitial nephritis. As the disease progressed parasites were found in the lumens of the tubules, and these represented daughter cells released from PKX parasites that had migrated to the tubules. Internal sporoblasts formed within these daughter cells (enveloping cells). The internal sporoblasts contained up to six daughter cells and some sporoblasts organized into spores with two spherical polar capsules. Although the spores persisted for several months after the interstitial PKX and associated inflammation had subsided, they did not complete their development as indicated by the fact that they remained within the enveloping cell and did not form valves.

The relationship of this spore to the vegetative stages was studied further by a transmission experiment. The myxosporean forms were only observed in the kidney tubules, while typical PKX also occurred in the blood and spleen. Parasite-free fish injected with the blood and spleen of infected fish developed both forms of the parasite, which further substantiates that PKX is the prespore form of the intraluminal myxosporean.

Because only incomplete spores were observed, the more precise taxonomic status of PKX was not determined. However, intraluminal stages of PKX show similarities to the genera Sphaerospora, Mitraspora and Parvicapsula. Furthermore, interstitial stages of PKX resemble the early stages of Sphaerospora.

The incomplete spore developnent and severe inflammatory response to PKX indicates that salmonids may be abnormal hosts. Fish were immunosuppressed with cortisol implants, and they exhibited greater densities of interstitial and intraluminal PKX but less interstitial hypercellularity. However, spores did not develop further than those observed in natural epizootics. This study supports the hypothesis that PKX is an early form of a sporean and that salmonids are abnormal hosts. A non-salmonid fish may be the primary host for PKX in which sporulation is completed.

Cover page: The Development of the PKX Myxosporean, the Causative Agent of Proliferative Kidney Disease, in Rainbow Trout Salmo gairdneri Richardson

Article

The importance of window view: Using an exploratory factor analysis to uncover the underlying latent dimensions

Kent, Michael George

Indoor Environmental Quality (IEQ) (2018)

This report outlines a statistical method used to evaluate the subjective ratings given to an image of a window view. An online survey containing questionnaire items that I believe influence the observer’s perception of the view were listed and distributed online. In total, 181 subjective responses were collected. Participants were asked to rate each item in the survey based on the perceived level of agreement or importance for each question. To analyse the data, I used an exploratory factor analysis. Of the 30 question items listed in the survey, four underlying latent factors were extracted. Namely: ‘subjective responses to the window view’, ‘physical features of the view’, ‘physical features of the window’, and ‘work-related responses’, respectively. These are listed in order of the amount of variance that they could explain within the data. The results of the analysis show how responses to several different questionnaire items refer to the same latent factor. I believe that the findings can be used towards the development of a predictive model to evaluate window view satisfaction. Specifically, when measuring a smaller, but manageable number of subjective responses in a survey to explain a complex construct of human behaviour such as the perceived importance of window view.

Cover page: The importance of window view: Using an exploratory factor analysis to uncover the underlying latent dimensions

Article
Peer Reviewed

Predicting Window View Preferences Using the Environmental Information Criteria

UC Berkeley Previously Published Works (2023)

Daylighting standards provide an assessment method that can be used to evaluate the quality of window views. As part of this evaluation process, designers must achieve five environmental information criteria (location, time, weather, nature, and people) to obtain an excellent view. To the best of our knowledge, these criteria have not yet been verified and their scientific validity remains conjectural. In a two-stage experiment, a total of 451 persons evaluated six window view images. Using machine learning models, we found that the five criteria could provide accurate predictions for window view preferences. When one view was largely preferred over the other, the accuracy of decision tree models ranged from 83% to 90%. For smaller differences in preference, the accuracy was 67%. As ratings given to the five criteria increased, so did evaluations for psychological restoration and positive affect. Although causation was not established, the role of most environmental information criteria was important for predicting window view preferences, with nature generally outweighed the others. We recommend the use of the environmental information criteria in practice, but suggest some alterations to these standards to emphasize the importance of nature within window view design. Instead of only supporting high-quality views, nature should be promoted across all thresholds dictating view quality.

Cover page: Predicting Window View Preferences Using the Environmental Information Criteria

Article
Peer Reviewed

Stimulus range bias leads to different settings when using luminance adjustment to evaluate discomfort due to glare

Imaging in Non-neurologic Oncologic Treatment Planning of the Head and Neck

UC Davis Previously Published Works (2019)

Imaging is critical for the diagnosis and staging of veterinary oncology patients. Although cytology or biopsy is generally required for diagnosis, imaging characteristics inform the likelihood of a cancer diagnosis, can result in a prioritized list of differentials that guide further staging tests, and assist in the planning of surgery, radiation, and chemotherapy options. Advanced imaging, such as CT and MRI, can better define the extent of disease for surgical and radiation planning for head and neck cancer cases in particular. Additionally, new imaging technologies are continually being translated into veterinary fields, and they may provide more options for cancer patients as they become more widely available.

Cover page: Imaging in Non-neurologic Oncologic Treatment Planning of the Head and Neck

Article
Peer Reviewed

Indoor environmental quality in WELL-certified and LEED-certified buildings.

UC Berkeley Previously Published Works (2024)

International building certification systems, such as the WELL and Leadership in Energy and Environmental Design (LEED) standards, play a pivotal role in the design of healthy and sustainable buildings. While LEED adopts a holistic approach to designing healthy and sustainable buildings, the WELL standard has a strong emphasis on human health, comfort, and well-being. Although prior research has revealed inconsistent results for occupant satisfaction in office buildings with WELL certification compared to buildings without WELL certification, or are certified using another certification system (e.g., LEED), most of these comparisons tend to lack methodological rigor. This study used a statistical procedure to match and compare 1634 occupant surveys from LEED-certified buildings to 1634 surveys from WELL-certified buildings. Six important architectural and experiential parameters were matched, masking their influence on the outcome. Overall building and workspace satisfaction was high in both WELL-certified buildings (94% and 87%) and LEED-certified (73% and 71%). We found that there is a 39% higher probability of finding occupants who are more satisfied in WELL-certified buildings compared to LEED-certified buildings, indicating occupant satisfaction is higher in buildings with WELL certification. Although we were unable to pinpoint the reason for higher occupant satisfaction in WELL-certified buildings, the results consistently showed that perceived indoor environmental quality was enhanced across all parameters except for the amount of space.

Cover page: Indoor environmental quality in WELL-certified and LEED-certified buildings.

Article
Peer Reviewed

Experimental evaluation of visual flicker caused by ceiling fans

Indoor Environmental Quality (IEQ) (2020)

Significant energy savings can be achieved by promoting elevated air speed using ceiling fans by increasing the cooling set-point temperature of an air-conditioning system. However, fan blades that obstruct the light from an artificial ceiling fixture from the relative viewing position of a building occupant could causes problems of visual flicker. We performed experiment to identify the effects of visual flicker caused by ceiling fans. Two different designs were used that had either opaque or transparent blades, which created different levels of visual flicker. These were installed in two test-rooms with similar environmental conditions. Forty-six participants took part in the study under a crossover design. Participants completed three cognitive visual tasks in both conditions: Stroop-test, switcher and digit-span tasks, respectively. Before and after completing the tasks, subjective evaluations were also given to several variables. Comparisons across the two ceiling fans showed the following results: a small and just significant reduction of performance in the digit-span task but not for the Stroop-test and switcher-task; some adverse symptoms related to visual flicker, which were not found when directly comparing the two ceiling fans against each other; and a higher reported frequency of discomfort caused by visual flicker. While the effect we uncovered in our study was small and did not influence all parameters, the exposure to visual flicker was relative short and we do not yet know how building occupants may react across a longer period. If issues of visual flicker are not addressed, it may have adverse consequences on building occupants.

Cover page: Experimental evaluation of visual flicker caused by ceiling fans

Article
Peer Reviewed

Indoor environmental quality and occupant satisfaction in green-certified buildings

UC Berkeley Previously Published Works (2019)

Green-building certification systems aim at improving the design and operation of buildings. However, few detailed studies have investigated whether a green rating leads to higher occupant satisfaction with indoor environmental quality (IEQ). This research builds on previous work to address this. Based on the analysis of a subset of the Center for the Built Environment Occupant Indoor Environmental Quality survey database featuring 11,243 responses from 93 Leadership in Energy and Environmental Design (LEED)-rated office buildings, this study explores the relationships between the points earned in the IEQ category and the satisfaction expressed by occupants with the qualities of their indoor environment. It was found that the achievement of a specific IEQ credit did not substantively increase satisfaction with the corresponding IEQ factor, while the rating level, and the product and version under which certification had been awarded, did not affect workplace satisfaction. There could be several reasons for this, some of which are outside the control of designers and beyond the scope of rating systems based primarily on design intent. The challenges and priorities facing building professionals, researchers and green building certification systems are discussed for the creation of more comfortable, higher performing and healthier green-rated buildings.