Dissertation Defense Announcements

The need to supply electricity to the building sector is growing worldwide. Currently, integrating photovoltaic (PV) panels into building rooftops is the primary method for harnessing solar energy. However, this practice, along with the use of solar farms, contributes to power grid fluctuation issues, known as the duck curve. Two main issues associated with the duck curve are PV power curtailment at midday and a sudden increase in utility operation during late afternoon hours. These problems are more significant in regions with higher PV power penetration into the grid, raising concerns that the current power grid infrastructure may not be able to accommodate the operation of conventional utilities alongside PV power generators.

Since the building sector is a major electricity consumer, supplying this sector's demand with an optimized PV system that not only meets building electricity needs and reduces energy consumption but also mitigates duck curve issues can significantly contribute to energy sustainability. This thesis investigates the impact of Building-Integrated Photovoltaic (BIPV) systems in mitigating power grid fluctuations through a comprehensive analysis. The findings of this study are presented in four research papers, each addressing a specific aspect of the main research objective. A brief summary of the findings is as follows:

Paper One: "Circuit Connection Reconfiguration of Partially Shaded BIPV Systems: A Solution for Power Loss Reduction" explores solutions to tackle power drops in BIPV façades due to partial shading conditions. The paper presents a novel circuit connection that significantly reduces power output reduction in BIPV façade systems.

Paper Two: "Comprehensive Analysis of Energy and Visual Performance of Building-Integrated Photovoltaics in All ASHRAE Climate Zones" examines various BIPV typologies, including PV-south louvers and PV-mounted roofs, in terms of building energy consumption, PV power output, and occupants' visual comfort. Results indicate that PV-south louvers significantly reduce building energy consumption in very hot, hot, and warm climates. In colder climates with significant heating demands, roof-mounted systems provide a better balance between power generation and solar heat gain. PV-south louvers effectively reduce glare on office working surfaces while providing the desired illuminance levels for occupants. However, PV-mounted roofs can cause excessive illuminance, leading to disturbing glare over large portions of the floor area.

Paper Three: "Assessing the PV-Integrated South Façade in Mitigating the BIPV System Oversupply" evaluates the effectiveness of PV-south louvers in reducing BIPV power curtailment at midday. The results show that these typologies effectively reduce power curtailment in very hot, hot, and warm climates, except in warm-marine sub-climate zone (3C). In mixed climates, the performance of these typologies varies across different months.

Paper Four: "Assessing the Impact of PV-Integrated West Façade in Alleviating the Duck Curve Steep Ramp in All ASHRAE Climate Zones" investigates the impact of PV-west fins on alleviating the duck curve's steep ramp in the late afternoon. The impact is limited in very hot and hot climates but shows more potential in warm, mixed, and cool climates. Cold, very cold, and Arctic climates exhibit higher effectiveness during warmer months.

This thesis provides a comprehensive analysis of the impact of BIPV systems in mitigating the duck curve issue. By optimizing BIPV configurations and understanding their performance across different climate zones, the findings of this thesis offer valuable insights into improving building energy and BIPV power production efficiency as well as addressing grid stability issues associated with the fast-growing integration of PV systems into the built environment.

Leadership is a conceptually ambiguous term, which creates a challenge for the practice of leadership development: How do we develop something without knowing what that “something” means? Prior research has not explored this challenge, and its existence has not stopped organizations from spending billions of dollars a year on leadership development. In this dissertation, I start by asking how individual leadership development programs can function in light of leadership’s ambiguity. I use qualitative theory-building methods in study 1 to generate an explanation for this question that is grounded in the concept of strategic ambiguity. In study 2, I followed up on one of the key implications of this explanation—potential competing incentives between science and practice—and asked how the science and practice of leadership development (mis)aligns. For this study, I used inductive coding on two sources: academic recommendations drawn from leadership development and leader behavior articles, and practitioner claims drawn from client/customer-facing websites. In the closing chapter, I develop big picture implications and questions for the science and practice of leadership and its development.

Domestic violence (DV) is widely recognized as a significant problem with detrimental impacts on the mental, physical, and socio-economic well-being of individuals, families, and the broader community. Despite various resources designated to support survivors, they may not be easily accessible or readily available. More importantly, DV survivors are often reluctant to divulge their experiences with others and may even refrain from seeking assistance because of social, emotional, privacy, and cultural concerns. As the immediate response to DV is crucial to survivors' physical and psychological well-being, they need prompt and non-blaming first responders.
Technological advancement, particularly in automated Conversational Agents (CAs), is progressing rapidly. CAs are gaining attention as a promising tool for providing counseling and support, addressing the above-mentioned challenges with survivors using traditional supporting resources. The primary objective of this dissertation research is to design, develop, and evaluate a CA-based solution that assists DV survivors in receiving support, enhancing their awareness, and increasing their access to services. To this end, we first identify the meta requirements and design principles of CA for survivors by interview-ing DV professionals, then design and develop SafeHaven, a CA-based prototype for supporting DV survivors, by following the design principles and meeting the meta requirements, and finally evaluate the effectiveness and user perception of SafeHavan by conducting user experiments.
Our findings suggest that CAs should empathize with survivors' experiences and provide them with meaningful informational, tangible, and emotional support, ensuring their safety as well as maintaining a transparent, private, and trustworthy dialogue. An evaluation of the CA was carried out with 36 participants, including DV survivors, their friends, family, and professionals, evaluating, among other metrics, the emotional, informational, and instrumental support provided. It was discovered that the CA outperformed traditional online searches and ChatGPT in terms of providing emotional, informational, and instrumental support, high information quality, and user trust.
This research identifies meta-requirements and design principles for designing a CA for DV survivors. This is the first research to evaluate the effectiveness of CAs in assisting individuals with DV, providing tailored, context-sensitive assistance that is superior to the capabilities of traditional search engines and general AI platforms like ChatGPT. In a broader sense, our results will be instrumental in guiding the development of future CA-driven support systems for DV survivors. This dissertation emphasizes the transformative potential of CAs for survivors of DV, as well as significant implications for CA developers, DV organizations, and support groups, proposing innovative strategies for enhancing anonymity, accessibility, and support for survivors.

Stressed young adults are at greater risk of lifetime higher morbidity and mortality, highlighting a need for feasible and effective approaches to improve stress management in this population. Mindfulness, defined as intentional awareness of the present with an attitude of nonjudgment, is a promising intervention to improve a host of physical and mental health outcomes. The stress-buffering hypothesis posits that mindfulness may mitigate harmful consequences of chronic stress through top-down modulation of stress perception as well as bottom-up regulation of stress response systems (Creswell & Lindsay, 2014). Further, Lindsay & Creswell’s Monitor & Acceptance Theory (MAT; 2017) proposes that experiential acceptance is a key component of these effects, without which stress reactivity may be exacerbated. This study sought to investigate the stress-buffering mechanisms of mindfulness and replicate prior research supporting MAT using a single session dismantling study comparing regulated breathing control, monitor-only, and monitor + accept conditions in a sample of 33 stressed young adults who completed an in-lab social evaluative stressor. A series of linear hierarchical regressions and multilevel models were utilized to compare condition effects on physiological and psychological stress responsivity and reactivity, respectively. Individual-level predictors (e.g., trait mindfulness, self-compassion) that may moderate stress-buffering effects were also examined, and exploratory qualitative analysis of participants’ perceptions was conducted. No hypotheses were supported by the study’s findings, most likely due to the underpowered sample. Qualitative results further suggest that the study’s active control was potentially equally efficacious to the mindfulness conditions in buffering stress. Future research directions include clarifying the minimal amount of mindfulness practice needed to observe stress-buffering effects as well as investigating how mindfulness is most effectively learned in stressed populations.