Red hot American summer: Extreme heat and physical activity of adults

(Georgia Institute of Technology, 2018-12-20) Lanza, Kevin

This dissertation investigates the relationship between extreme summer heat and outdoor, indoor, and total (i.e., outdoor + indoor) physical activity levels of US adults. With the lack of physical activity across the US, public health practitioners and city planners are making concerted efforts to promote physical activity through formal interventions and the design of spaces, respectively. To inform physical activity interventions, researchers examine which factors associate with physical activity, one of which is temperature. The majority of studies exhibit a significant positive association between temperature and physical activity, yet no studies examine exceptionally hot summer days, which disproportionately impact cities and are set to become more prevalent in the future. This dissertation tests three novel questions: 1) how do hot days associate with outdoor, indoor, and total physical activity; 2) how do hot days influence the effect of built environment factors on outdoor physical activity; and 3) how do heat waves – consecutive hot days – associate with outdoor, indoor, and total physical activity? This work made use of self-reported physical activity and demographic data collected during summer 2016 for a National Science Foundation project (NSF award number: 1520803). The study sample included a spatial and demographic mix of ~50 adults per study city (i.e., Atlanta, Detroit, and Phoenix). Heat was measured as both hot days and heat waves (i.e., two or more consecutive hot days), utilizing air temperature and relative humidity data collected at each city’s major airport. The examined built environment factors (i.e., density, safety, trees, hilliness, connectivity, access to parks, and access to shops + services) were primarily collected from government sources and calculated within an 800m Euclidean distance of each study participant’s home address. Separate two-level growth curve models were run for each research question, version of the dependent variable (i.e., Any Activity and Recommended Activity), and location of physical activity (i.e., outdoor, indoor, and total). Multilevel modeling predicted that 1) hot days do not exhibit a significant association with indoor, outdoor, or total physical activity; 2) hot days do not significantly influence the effect of built environment factors on outdoor physical activity; and 3) heat waves do not exhibit a significant association with outdoor, indoor, or total physical activity. These findings refute the study hypotheses that extreme summer heat would decrease outdoor and total physical activity, while shifting physical activity to indoor, thermally comfortable environments. With high temperatures potentially not serving as a barrier to physical activity, cities should allocate resources to reducing the risk of exertional heat illness, an adverse health event expected to become more frequent with physical activity promotion and climate change.
What metropolitan-level factors affect Latino-owned business performance?

(Georgia Institute of Technology, 2018-11-07) Doyle, Jessica L. H.

An estimated 1.54 million Latinos are self-employed in unincorporated businesses, while the 2012 national Survey of Business Owners counted 3.3 million Latino-owned firms, with a total of $474 million in annual sales or receipts. This entrepreneurship is all the more remarkable given that Latinos traditionally begin their businesses with lower levels of personal capital and have historically had more difficulty obtaining formal startup capital from third parties such as banks or government agencies. While this observation holds true at the national level, different metropolitan areas may provide business environments more or less hospitable to Latino-owned businesses, due to such factors as industry mix, availability of financing, demographics, and local political expression of “welcoming” or anti-immigrant sentiment. This dissertation examines the question of what metropolitan-level factors affect Latino-owned business formation and performance. It finds that Latino entrepreneurs nationwide face persistent obstacles in the form of obtaining financing for both new and existing businesses, which can be addressed at the local level. However, certain concepts currently prominent in research about ethnic entrepreneurs, such as the makeup and geographic concentration of the “ethnic enclave” and the importance of prior history of immigrant settlement in the metropolitan area, may be less applicable to Latinos who come from a broader range of countries and settle in less dense metropolitan areas.
Will millennials stay in cities and travel without cars?

(Georgia Institute of Technology, 2018-08-24) Lee, Yongsung

Will millennials stay in cities and travel without cars? To answer this question, this dissertation examines heterogeneity in modality styles and residential preferences in a sample of millennials and members of Generation X in California in 2015. It finds that both sociodemographic/ economic characteristics and attitudes about various dimensions (e.g., preferred built environments, travel modes, and car ownership) account for the heterogeneous behavioral and choice patterns in the sample. These findings provide insights on the ways millennials may switch their modality styles or residential preferences in response to changes in sociodemographic/economic conditions or attitudes in the coming years. This dissertation highlights the use of latent-class approaches as effective for the identification of heterogeneity in tastes related to the travel behaviors and location choices of millennials. Researchers are advised to apply these approaches to longitudinal analyses. This research also informs planners and policymakers of dynamic changes in the form or share of latent classes in their region.
Quantitative analysis for modeling uncertainty in construction costs of transportation projects with external factors

(Georgia Institute of Technology, 2018-08-23) Baek, Minsoo

Highway construction costs are subject to significant upward and downward variations from project to project and over time. Variations in construction cost disturb transportation agencies in making right investment decisions and estimating accurate construction costs for projects. Transportation agencies face considerable uncertainty in estimating project costs that often leads to significant over- and under-estimation of highway construction costs. The underestimation of project costs can lead to cost overrun, financial problem, and project delay or cancellation. The overestimation of project costs results in an inefficient budget allocation of public funds that could be used on other needed projects. Transportation agencies can also face credibility issues with the public if cost estimation problems remain unresolved. A wide range of variables has been identified in different studies to explain variations in construction cost. There is a value in conducting a research study that attempts to consider a comprehensive list of variables with potentials to explain the variations. The study needs to simultaneously take into account all possible explanatory variables to examine their relations with construction costs. The overarching objective of this research is to assess the effects of several potential variables on explaining variations in submitted unit price bids for major asphalt line items in highway projects. First, stepwise regression analysis will be utilized to develop an explanatory model for describing variations in the submitted unit price bid. The identified variables used to build the explanatory model are classified into two major tiers. Tier 1 represents project specific factors, such as variables related to project characteristics, project location and its distance to major supply sources and price adjustment clauses. Tier 2 represents global and external factors, such as variables related to level of activities in local highway construction market, macroeconomic indicators and energy market conditions. Secondly, it is shown that there is a significant spatial correlation between construction project cost and geographical location of the project that a generalized linear modeling approach may overlook. Geographically weighted regression analysis will be conducted to develop explanatory models for describing variations in the submitted unit price bids considering the spatial correlation. Lastly, the effect of natural disasters on highway construction costs will be examined. Cumulative sum (CUSUM) control chart will be utilized to monitor and detect the change in submitted unit price bids for hurricane-impacted and not hurricane-impacted areas. The primary contributions of this research to the existing body of knowledge are: (1) creation of a multiple regression model to explain variations in submitted unit price bids; (2) creation of local regression models to describe variations in the submitted unit price bids considering the spatial correlation; and (3) empirical assessment of the impact of natural disasters on the variation in the submitted unit price bids. The primary contributions of this research to the state of practice are: (1) enhancing the capability of cost engineers in preparing more-accurate budgets and bids; (2) aiding a bottom-up estimating approach that requires more knowledge about the projects and market; and (3) helping capital project planners set and adjust the timing of the project lettings in the light of market conditions.
A functional modeling framework for interdisciplinary building design

(Georgia Institute of Technology, 2018-08-01) Cavieres, Andres

The process of Building Design, as in many other forms of design, requires the effective integration of different types of knowledge. However, and in the specific context of Building Information Modeling, only structural knowledge is formally represented. Other types of necessary knowledge, such as those related to the functionality of design, and the set of causal behaviors from which such functionality is delivered, remain tacit or indirectly referenced by using structural properties as proxy representations (e.g. geometry). The lack of a more comprehensive and rigorous representational framework to formally describe various behavioral and functional aspects of buildings limits the scope of semantics required to support more effective interdisciplinary collaboration and design integration. In particular, there is a lack of computational support to describe cross-cutting behavioral interactions and side-effects that occur among different building sub-systems, which often play a role in the satisfaction of functional goals. To address this problem, the research proposes the development of a representational framework for the functional and behavioral characterization of building systems and components based on the Functional Representation (FR) schema developed by Chandrasekaran and Josephson (2000), and its recent formalization following the DOLCE foundation ontology, by Borgo et al. (2009). A subset of FR axioms has been translated into Description Logic using the Web Ontology Language (OWL-DL) to explore query capabilities of the proposed framework to support identification of behavioral interactions based on inference capabilities of available OWL-DL reasoners. The dissertation provides a theoretical basis for the formulation of functional modeling capabilities currently not available in Building Design. In particular, these capabilities are intended to support the incremental elucidation of behavioral interactions that emerge across different building sub-systems, based on the principle of co-participation of structural entities in a same behavioral phenomena (category of perdurants). The elucidation is expected to be supported by computational inference from structural relations asserted in BIM models by various stakeholders, and at different stages of the design process.
From physical layout to spatial experience: Understanding the impact of visual interfaces on teamwork in primary care clinics

(Georgia Institute of Technology, 2018-07-31) Lim, Lisa

Teamwork among healthcare providers is critical for the safety and quality of patient care. Multiple national strategies and programs have been developed and recommended for implementation of a team-based approach to primary care, and many healthcare organizations are adopting team-based primary care clinics. However, little is known about how clinic layouts can support the teamwork of staff members in team-based primary clinics. To date, there has been little agreement on how clinic layouts should be designed to support the teamwork experiences of staff members and patients. Thus, different healthcare organizations advocate for unique and significantly different types of team-based clinic layouts. This study looked at four team-based primary care clinics to empirically investigate the relationships between visibility metrics and both patients’ and staff members’ teamwork experience. The results of the study showed that the visual interfaces between staff members and patients, as well as between different groups of staff members, were found to have significant associations with awareness, communication, backstage communication, and overall perception of teamwork. While no specific differences in awareness perceptions were reported between clinics, some negative consequences resulting from the lack of staff’s ability to see the clinic area and other staff members were observed. Staff members had to spend additional time searching for each other and had their patient care process obstructed when they could not see the clinic area or other staff workstations. The visual interface between staff workstations also significantly predicted staff communication patterns. Clinics providing more visual connections between staff workstations reported stronger perceptions of timely and frequent communication, and staff members talked frequently to other staff members whose workstations were visually and physically connected with their own workstations. Furthermore, clinics providing more visual connections between staff workstations reported higher teamwork perception. Surprisingly, more visual connections between patients and staff workstations were associated with lower teamwork perceptions from the patients’ perspective. The visual connections between patients and staff workstations (visual exposure to patients) also negatively affected staff backstage communication patterns. Clinics with higher visual exposure levels reported higher levels of concern for privacy while communicating patient information, and the staff members across all four clinics preferred not to talk about patients at visually exposed areas, even if the locations were inside team areas. The findings of the study support designing team-based primary care clinics to enhance the teamwork experience of both staff members and patients. It is worth noting that this study investigates the teamwork experience of not only staff members but also patients, who are critical entities of teamwork for patient-centered care in primary care clinics. The design implications are expected to be applicable for the teamwork of other settings, especially for strong programs where both inhabitants and visitors exist as main user groups of the spaces.
Investigating the potential of on-demand ride service and its impact on mode choice and accessibility

(Georgia Institute of Technology, 2018-07-31) Wang, Fangru

The recent advancement in information technologies has facilitated the emergence and growth of travel modes like ride-sourcing, car-sharing, and bike-sharing, providing travelers with unprecedentedly broad travel options. The nature of these options will significantly affect the way how people travel and engage in activities, and therefore lead to transport network impacts. Ride-sourcing, referring to app-based on-demand ride service (ODRS), exhibits similar traits of traditional taxis but provides better real-time information and lowered cost compared to taxis. The fast growth of ride-sourcing also reflects the trend known as Mobility as a Service (MaaS) and can be seen as a litmus test of connected and autonomous vehicles which will further transform the transportation landscape. This dissertation explores three main aspects of ODRS using a three-part analysis: an exploratory analysis of the role of ODRS in urban transportation, a discrete choice modeling to understand the choice of ODRS, and scenario forecasting to quantify the potential impact of ODRS on transport accessibility and equity. The dissertation results indicate the critical role that ODRS has in serving transport-disadvantaged population and multimodal travel and filling in gaps of transit, identify the socio-demographic, built environment, and trip characteristics associated with the choice of ODRS, and reveal the substantial accessibility and equity benefits of integrating ODRS with transit. The dissertation also shows strong performance of machine learning travel mode choices and suggests the further integration of machine learning with travel demand forecasting. The findings unveil the potentials of ODRS in elevating transport benefits of the existing infrastructure and point to strategies of leveraging ODRS and autonomous vehicles to improve transport mobility, accessibility, and equity. The results also reveal challenges of realizing the benefits of ODRS and incorporating ODRS into travel demand forecasting, which will have to rely on data collection, public-private collaboration, and research and practical exploration of synergizing ODRS with other travel modes.
Investigation of hybrid ventilation potential of commercial buildings in US

(Georgia Institute of Technology, 2018-07-30) Chen, Jianli

As one of the largest energy consumers in our society, commercial buildings take up approximately 20% of total energy consumption based on the data from Department of Energy (DOE). Among this energy consumption, nearly half of it is consumed by air conditioning systems for maintaining a comfortable thermal environment for building occupants. Despite this high energy consumption, complains of thermal comfort and health problems still commonly exist in air-conditioned buildings. The mean building satisfaction rate was only reported as 59% based on a large survey of building occupants, which is far below the minimum thermal comfort requirement in ASHRAE standard 55. Meanwhile, there also exist health problems in air-conditioned buildings, which include both building related diseases (typically caused by specific exposure to infectious indoor source) and sick building syndrome, which describes a group of general symptoms including eye or throat irritation, shortness of breath, visual disturbance etc. Thus, in these years, coupling natural ventilation with mechanical ventilation, hybrid ventilated buildings have attracted more attention from both academia and industry with increasing awareness of building sustainability. Hybrid ventilated buildings have the potential to minimize the energy bills for owners without compromising the thermal comfort of building occupants. Compared to the mechanical ventilated building, the hybrid ventilation system allows opening the window when the outdoor environment is favorable, which provides occupants with amenity to nature and saves energy in the building operation. Compared to the natural ventilation building, the hybrid ventilation building could protect the building occupants from the unfavorable outdoor environment with air conditioners on. As the first step to further popularize the hybrid ventilation building, this dissertation will provide a thorough investigation of the hybrid ventilation potential across different US climates with accounting for comprehensive and influential aspects related to the usage of natural ventilation, including different levels of uncertainties a hybrid ventilation building could experience, the influence of building intelligence and the impact of outdoor air quality. How to better assess the thermal comfort risks and utilize simulation to design this type of building will also be presented.
Development and validation of the universal design mobile interface guidelines through a mHealth application for individuals aging with multiple sclerosis

(Georgia Institute of Technology, 2018-07-30) Kascak, Ljilja

Similar to people who experience normal aging, mobile technologies provide great potential to support people aging with disability. However, there is a dearth of prior research on the needs and abilities of this user population. A large number of people with disabilities acquired in early or middle life are living longer. These individuals are experiencing the effects of aging earlier than others. Additionally, individuals aging with disabilities experience a combination of pre-existing impairments and age-related limitations, which often leads to a newly acquired age-related functional losses, comorbidities, and secondary age-related conditions. Although younger adults with disabilities may compensate for their impairments through the use of technologies, devices, and techniques, newly developed age-related limitations can reduce the effectiveness of these alternative approaches and reduce the quality of life (QOL). Mobile technology provides great potential to help individuals aging with disabilities to meet their needs. Nevertheless, there is a need for further research to solve the problems with access, usability, and utility to better understand the individualized preferences and support the needs of this unique population. Moreover, this imposes the need for personalized technologies that assist people aging with disabilities to adapt to the challenges of later life and to improve their QOL. Several design strategies are used to address the usability issues of desktop and mobile interfaces that are relevant for an aging population. Four of the most commonly applied strategies include Universal Design, Design for Aging, Universal Usability, and Guidelines for handheld mobile device interface design. Analysis of the guidelines suggested that none of the four strategies alone were sufficiently comprehensive and inclusive enough to meet the range and diversity of usability needs of older adults including those aging with disabilities within the environment of mobile interfaces. The purpose of this research project was to develop a comprehensive integrative universal design strategy, the Universal Design Mobile Interface Guidelines (UDMIG) for people aging with and without disabilities. The mobile health (mHealth) self-management holistic application that meets the health and wellness needs of individuals aging with Multiple Sclerosis (MS) and provides personalized and customizable support, MS Assistant, was designed and evaluated. The UDMIG were validated through their application to the design of the mHealth app.
On the role that specific domain knowledge and procedural strategies play in defining the episodic nature of architectural design formulation

(Georgia Institute of Technology, 2018-07-24) Soza Ruiz, Pedro Alejandro

This dissertation presents a study of design activity based on the analyses of fifty-six design processes taken from fourteen designers which were give four related architectural problems. The motivating interest was to investigate what is specifically distinctive about the architectural design process, with a focus on how the activity is organized or planned, and on how knowledge of different kind and external visual representations—sketches—are brought into play. These considerations and interests are derived from the assumption that the cognitive processes underlying the design activity are embodied and distributed throughout the materials and techniques used for the purpose. Findings reveal that the design activity is structured episodically, a feature that is not yet discussed adequately within extant literature on the topic. Episodes are described as forms of continuous activity grounded in specific forms of external representations and addressing a cluster of related sub-problems. Results also showed that unfamiliar tasks and settings generated larger number of episodes, which is conformity with the thesis that architects address novel design challenges by breaking up the overall design task into a number of smaller and more familiar sub-tasks, but that this restructuring emerges during the context of the design. Further findings concern the nature of these episodes. Episodes were found to fall into three main types, those concerned with issues of program and spatial organization, those concerned with site and physical context, and those with formulating broad goals. The quality of the designs depended not so much on the number of such episodes, or their order, but on their richness measured in terms of the number of design issues addressed within them and their variety.