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There have been an increasing number of materials developed that show multifunctional chromogenic properties (such as electrochromism, electrofluorochromism, or photochromism), but to date, few materials have shown all three properties. Materials that are electrochemically and optically active are attractive for a diverse set of applications that include smart-windows, lighting, sensing, energy production, and conservation. Achieving systems made from organic, cost-effective, readily synthesized materials would make them easy to utilize in a variety of fields. Multifunctional chromogenic dipyridinium thiazolo(5,4-d)thiazole (TTz) show promise in achieving these needs as they offer high contrast color change, high fluorescent quantum yields above 90%, and water processability while made from inexpensive starting materials. The planar, rigid, heterocyclic TTz core improves stability and reversibility as the TTz reduces from yellow TTz2+ to purple TTz•+ to blue TTz0 compared to other viologen systems.
When implemented in a low-cost poly(vinyl alcohol) (PVA)/borax hydrogel device using conductive glass electrodes, the TTz can change color and fluorescence intensity with applied voltage or light exposure. The electrochromism offers 75% transmittance contrast that is stable for 250 on/off cycles and electrofluorochromism with >90% contrast. By adjusting gel components and coating/drying the hydrogel, a variety of photochromic thin films were produced. Remarkably, the TTz-embedded films retain their high contrast chromogenic properties showing photochromism (yellow TTz2+ to blue TTz0 color change) and photofluorochromism after only one minute of light exposure. After turning blue, the oxidation back to yellow occurs through interactions with oxygen. This is potentially an effective way to optically gauge the presence of oxygen which is useful for a variety smart packaging applications for food, pharmaceuticals, and electronics. The color change speed and contrast can be tuned by adjusting borax and TTz concentrations. Because the TTz’s show multifunctional capabilities, photo-charging battery devices are tested to indicate the creation and storage of electrical charge when illuminated. When paired with the appropriate catholyte and membrane, TTz shows evidence of photocharging in hydrogel and film devices. Comparing charge discharge curves of the battery devices, illumination can increase voltages by 0.2 V and improve charging capacity. This work shows the remarkable multifunctional electroactive and photoactive properties of dipyridinium thiazolothiazole materials as well as their implemented to yield reversible, high contrast electrochromism, electrofluorochromism, photochromism, photofluorochromism, and light responsive charging.
At-home DNA testing and sharing in public genealogy databases are becoming widespread. This will facilitate finding out ancestry, genetic relatives, biological parents, making new connections, advancing medicine, and determining predisposition to various diseases and health issues. While the biomedical community glorifies the uses of the genomics revolution, the expanded obtainability of such sensitive data has substantial implications for individual privacy as genes carry sensitive personal information about human traits and predispositions to any diseases. Furthermore, DNA data has identification capability (e.g., forensics) as well as reveals familial interconnections. However, commercial DNA testing is not vigorously governed by any laws and policies. The privacy implications of public DNA data sharing remain largely unexplored. This dissertation explores users' privacy concerns and proposes a method for communicating the risks to users to inform users when sharing their DNA data.
In the first study, we explored users' perceptions regarding DNA data. We asked about their views of at-home DNA testing and sharing, followed by their expected benefits and concerns. We also talked about public genealogy databases like GEDmatch. We focused on understanding the users' preferences and perceptions on the disclosure of their genetic information under the different types of platforms and entities. Our results show that users are mostly unaware and uncomprehending of the interconnected nature of genetic data. We noted users' general perceptions and focused on understanding their preferred privacy controls while sharing their DNA data, their desired settings, policies, and rules.
From this study, we identified the need to develop a privacy-enhancing technology such that the users can make an informed choice while sharing DNA data. We also found that several policies and settings should be to preserve the privacy of sensitive data. With these findings in mind, the ultimate objective of this dissertation is to design and implement privacy risk communication methods that aid users in comprehending the risks and benefits associated with sharing DNA data, as well as enhancing transparency in access control. To evaluate the effectiveness of our developed risk communication approach, we deployed it within an existing platform, allowing us to assess users' decision-making processes and gain a deeper understanding of the nature of DNA data.
At-home DNA testing and sharing in public genealogy databases are becoming widespread. This will facilitate finding out ancestry, genetic relatives, biological parents, making new connections, advancing medicine, and determining predisposition to various diseases and health issues. While the biomedical community glorifies the uses of the genomics revolution, the expanded obtainability of such sensitive data has substantial implications for individual privacy as genes carry sensitive personal information about human traits and predispositions to any diseases. Furthermore, DNA data has identification capability (e.g., forensics) as well as reveals familial interconnections. However, commercial DNA testing is not vigorously governed by any laws and policies. The privacy implications of public DNA data sharing remain largely unexplored. This dissertation explores users' privacy concerns and proposes a method for communicating the risks to users to inform users when sharing their DNA data.
In the first study, we explored users' perceptions regarding DNA data. We asked about their views of at-home DNA testing and sharing, followed by their expected benefits and concerns. We also talked about public genealogy databases like GEDmatch. We focused on understanding the users' preferences and perceptions on the disclosure of their genetic information under the different types of platforms and entities. Our results show that users are mostly unaware and uncomprehending of the interconnected nature of genetic data. We noted users' general perceptions and focused on understanding their preferred privacy controls while sharing their DNA data, their desired settings, policies, and rules.
From this study, we identified the need to develop a privacy-enhancing technology such that the users can make an informed choice while sharing DNA data. We also found that several policies and settings should be to preserve the privacy of sensitive data. With these findings in mind, the ultimate objective of this dissertation is to design and implement privacy risk communication methods that aid users in comprehending the risks and benefits associated with sharing DNA data, as well as enhancing transparency in access control. To evaluate the effectiveness of our developed risk communication approach, we deployed it within an existing platform, allowing us to assess users' decision-making processes and gain a deeper understanding of the nature of DNA data.
Access to inclusive school settings is associated with many benefits for students with intellectual and developmental disabilities in the areas of academics (Agran et al., 2020; Kurth & Mastergeorge, 2010), social skills (Kleinert et al., 2015; Lyons et al., 2011; Schwab et al., 2015), and communication skills (Ballard & Dymond, 2017; Kleinert et al., 2015), among others. However, challenging behavior serves as a major barrier to inclusive school settings for some students with IDD (Agran et al., 2020; Gee, 2020; Giangreco, 2020; Kleinert, 2020). Given the benefits associated with access to inclusive school settings, it is critical that this barrier is addressed. One way in which challenging behavior can be addressed in school settings, including inclusive school settings, is through the use of function-based interventions. Function-based interventions are targeted interventions that are based on the results of a functional behavior assessment and are aligned with the function of a student’s challenging behavior (Gage et al., 2012; Jeong & Copeland, 2020). It is critical that the contextual fit of a function-based intervention is considered, as interventions that take contextual fit into consideration are more effective than those that do not (Monzalve & Horner, 2021). Functional communication training is an example of a highly effective function-based intervention that is implemented to teach functionally equivalent, socially appropriate communication skills and address challenging behavior. The literature on the effectiveness of functional communication training spans across age groups, settings, interventionists, and disability categories (Cooper et al., 2020; Hume et al., 2021), including students with intellectual and developmental disabilities (Andzik et al. 2016; Walker, Lyon, et al., 2018). Although there is emerging evidence demonstrating the effectiveness of functional communication training implemented with students with intellectual and developmental disabilities in inclusive school settings (Masud et al., 2022), the research is very limited. Further, there are no functional communication training studies that focus on a peer as an interventionist. The current study extends the literature on functional communication training for students with intellectual and developmental disabilities by demonstrating implementation by a peer mentor in an inclusive high school setting. The purpose of this study was to examine the effects of peer-delivered functional communication training on the functionally equivalent communication responses and challenging behavior of a high school student with intellectual and developmental disabilities, the collateral effects of the intervention on various student communication behaviors, and the degree to which educator team member participants and student participant found the intervention to be socially valid. Results of this study indicated that the functional communication training intervention had no effect on student functionally equivalent communication responses or challenging behavior. However, there is evidence of positive collateral effects as the student participant’s rates of various communication behaviors increased after the intervention was implemented. Finally, all participants found the intervention to be socially valid across most measures, though there were some concerns about the limited amount of time and potential student discomfort. The dissertation includes a discussion of each of the research questions, limitations of the study, directions for future research, and implications for practice.
Chapter 2 explores the feasibility, requirements, and challenges associated with integrating AI capabilities into AR systems to enhance the safety of highway work zones. This chapter delves into the feasibility, requirements, and challenges associated with incorporating AI capabilities into the AR system to develop a predictive safety system that can proactively identify potential hazards and issue timely warnings to workers. The outcomes of this chapter indicate that the real-time communication latency and AI execution latency meet the tight timing constraints of a real-time safety system. The early user research demonstrates positive reception and acceptance of the proposed safety framework and interface by highway maintenance and operation professionals across multiple states in the US.
Chapter 3 focuses on conducting a mixed-method usability investigation of the proposed AR-based safety system using a high-fidelity prototype. The investigation assesses aspects such as user interface design, interaction patterns, and user feedback to evaluate the overall usability and effectiveness of the technology in enhancing roadway work zone safety. The findings indicate that participants rated the usability of the system above average in both indoor and outdoor settings and perceived a reasonable level of mental effort. Perceived trust was found to be significantly correlated with usability, underscoring its importance in user experience.
Chapter 4 examines the impact of different sensory modalities on worker reaction times in augmented reality warnings within roadway work zones. The analysis of data from experiments provides insights into the effectiveness of various warning modalities, including visual, audiovisual, haptic visual, and combined haptic audiovisual cues, in improving worker response times. The findings indicate that the haptic visual design elicited the fastest response on average among the participants, and its performance was comparable to that of the audio haptic visual design. Furthermore, both of these designs demonstrated significantly faster reaction times compared to visual and audiovisual warnings. The results also indicate that reaction times to augmented reality warnings in real-world outdoor scenarios were generally longer and exhibited greater variability compared to baseline desktop warnings and simulated AR in virtual reality. Surprisingly, VR simulated warnings did not show statistically significant shorter reaction times compared to their real-world counterparts. These observations suggest that simulating AR in virtual reality may not accurately replicate the reaction times observed in real-world situations.
Collectively, the results from these chapters demonstrate the usability, perceived safety benefits, and potential for timely notifications offered by the proposed AR-based safety system. This research also contributes to establishing best practices for designing time-sensitive safety systems, prioritizing situational awareness, and implementing worker-centered design principles in AR safety systems. Ultimately, the findings have the potential to significantly enhance the safety of highway workers and the broader workforce operating in roadway work zones.
Learning prepositions is very important for students with an intellectual disability to engage in functional communication behaviors. In addition, it is important for the students with intellectual disability to engage in physical activity at school because they spend the majority of their waking hours during weekdays at school. One way to increase both academic learning and physical activity level is to combine academic core content learning with physical activity. Simultaneous prompting is one of the response prompting procedures, which are evidence-based practices, and has been used as an effective way to teach both academic core contents and functional skills to students with intellectual disability. Peer tutoring also has been an effective teaching strategy to increase social aspects as well as academic learning for students with intellectual disability. In this study, I used a single-case multiple probe across participants design to examine the effects of a peer-delivered simultaneous prompting procedure in teaching locative prepositions combined with movement skills to students with intellectual disability. Five elementary school students with a mild to moderate intellectual disability participated in this study as the target participants. One peer without a disability enrolled in the same school with the target participants was the peer tutor and a data collector. The special education teacher participated in social validity data collection. Results of the study demonstrated a functional relation between the first primary dependent variable (i.e., action of prepositions to verbal prompt) and the intervention. Three out of five target participants showed some improvement in responding to nontargeted information (i.e., labeling of prepositions). For the movement skills measured by the Test of Gross Motor Development (TGMD; Ulrich, 2000), all target participants acquired higher scores in the posttest compared to their pretest scores. Further, four out of five target participants demonstrated some improvement in generalizing their knowledge of action of prepositions to verbal prompt to other materials and three target participants showed improvement in generalizing their knowledge of labeling of prepositions to other materials. Social validity data collected from the special education teacher, the peer tutor, and the target participants showed that they agreed the intervention was beneficial to all participants academically and socially. In addition, throughout the study, the peer tutor conducted both probe and training sessions with high procedural fidelity data. Limitations of the current study and suggestions for future research are discussed.
The need for ultra-precision optical components with intricate geometric profiles has grown rapidly in the last few decades. Applications of precision optical lenses range from consumer electronic products to optical sensing instruments, microscopy, astronomy, etc. Typically, polymer-based lenses have been used and have dominated the industry so far, but due to the advantages of using glass components, the demand for ultra-precision glass aspherical components has been steadily raising. In fact, it is estimated that the demand for aspherical glass lenses will grow at a rate of 6.5% in the next five years. However, the conventional manufacturing processes when used for producing aspherical glass components become time-consuming and expensive.
Precision glass molding (PGM) technology provides an alternative manufacturing technique to fabricate aspherical glass lenses and irregular optical products. It has the advantages of high forming accuracy, short manufacturing cycles, low cost, and high volume production compared to the traditional manufacturing process. However, the process has a few drawbacks such as lens profile deviations, stress birefringence, etc. Typically, the mold surfaces are machined to be exact negatives of the required lens profile, assuming the lens would take the shape of the molds. But in reality, the complex mechanical behavior of the glass and its high-temperature dependence affects the final lens profile at room temperature. In addition to geometric deviations, the rapid temperature changes, often as much as several hundreds of degrees, in a short time affect the performance of the molded lens. These drawbacks need to be addressed before the glass molding process can be used as a viable option for mass-producing optical components.
As such, in this dissertation, a coupled thermo-mechanical finite element model is established to simulate the precision glass molding process on two different glass types, D-ZK3 (CDGM) and P-SK57 (Schott). The glass is modeled as a thermo-viscoelastic material by defining the stress and structural relaxation parameters. A new testing technique based on the cylinder compression test is developed in this study to extract the viscoelastic parameters at different temperatures. The obtained material parameters when used in the numerical simulations showed a good agreement with the experimental data throughout the testing temperature range. Further, the viscosity of the glass (a highly sought-after property of glass in precision molding) is obtained as a by-product of the proposed material calibration test. Finally, the structural relaxation parameters are obtained from the impulse excitation test based on ASTM standard E1876. All the experiments required for fully calibrating the viscoelastic response of the glass are performed on a precision glass molding machine, Moore Nanotech GPM170 machine. The obtained material parameters are used in the finite element model to predict the lens deviations and the stresses in the molded lens. A mold compensation technique is used to correct the mold profiles for any deviations. The lens molded using the corrected molds is shown to fall within the designer's specifications.
The process parameters used during the molding process play a vital role in determining the profile accuracy and the optical quality of the molded lens. Hence, it is important to determine an optimal parameter set before applying any mold compensation techniques. But due to the obscure and complex nature of the process, determining the parameter sets empirically is a tedious process. As such, in this study, the developed numerical model is used to individually analyze the different process steps and the corresponding process parameters on the profile deviations and the residual stresses in the molded lens. The results obtained in this study can be used as a reference to fast-track the manufacturing process.
In recent decades, the demand for ultra-precise optical components with intricate geometric profiles has increased dramatically. Traditionally, polymer-based lenses have dominated the industry, but due to the benefits of using glass components, the demand for ultra-precision glass aspherical components has been rising consistently. When producing aspherical glass components, however, conventional manufacturing processes become time-consuming and expensive. Precision glass molding (PGM) technology offers an alternate method of production for aspherical glass lenses and irregular optical products. Compared to the conventional manufacturing process, it has the advantages of high forming accuracy, short manufacturing cycles, low cost, and high-volume production. However, the process has a few drawbacks, such as lens profile deviations, stress birefringence, etc. Before the glass molding process can be a viable option for mass-producing optical components, these drawbacks must be addressed. As such, a coupled thermo-mechanical finite element model is developed in this dissertation to simulate the precision glass molding process on two distinct glass varieties, D-ZK3 (CDGM) and P-SK57 (Schott). A novel testing method is developed to precisely characterize the viscoelasticity of the glass material. It is demonstrated that the obtained material parameters accurately depict the experimental data at various molding temperatures. In addition, the material testing experiments are designed to be implemented on a glass molding machine, simplifying the development and characterization of different moldable glass materials. The obtained material parameters are implemented in the finite element model to predict the profile deviation in the molded lens and compared with experimental results. A mold compensation technique is used to correct the mold profiles. The lens molded on the modified molds is shown in fall within the tolerance specifications. However, it was observed that the process parameters used during the molding process have an influence on the deviations and the stresses in the molded lens. Therefore, it is essential to optimize the molding process prior to implementing mold compensation techniques. The developed numerical model is used to analyze the impact of various process stages and parameters on the optical quality of molded lenses. Based on the observations, a modified molding process was developed which is shown to minimize the influence of the molding parameters on the deviations and the residual stress. In addition, it was demonstrated that the modified manufacturing process reduces the total cycle time for producing a glass lens of comparable optical quality by more than 50%, reducing the manufacturing cost of a molded glass lens.
Human-AI co-creativity involves a human and an AI collaborating as partners on creative tasks such as generating music or art. This research domain is particularly timely as AI becomes increasingly prevalent in collaborative spaces. With the availability of ChatGPT, DALL.E 2 and other generative AI tools, co-creative AI is gaining increased popularity. Unlike general human-computer interaction, human-AI co-creation establishes a complex relationship where AI actively contributes, assumes human-like roles, and generates novel content blended with the user's contribution. Therefore, designing engaging and ethical co-creative systems poses challenges due to the open-ended nature of human-AI interaction. This dissertation contributes empirically and theoretically to the design of engaging and ethical human-centered co-creative AI. It focuses on four main areas: designing interaction, the impact of AI-to-human communication, ethical guidelines and understanding users' mental models of co-creative AI in human-AI co-creation. Firstly, this dissertation introduces the Co-Creative Framework for Interaction Design (COFI), which describes the broad range of possibilities for designing interactions in co-creative AI. Additionally, an analysis of 92 existing co-creative AI identifies common interaction design trends and research gaps. The analysis reveals a notable gap in commonly employed interaction designs: the absence of two-way communication between humans and AI, where AI cannot communicate with humans, limiting their potential as partners. Inspired by the research gap identified, this dissertation delves into examining the impact of AI-to-human communication on user experience and perception of co-creative AI. Two prototypes of a co-creative system, with and without AI-to-human communication, were developed to facilitate a comparative study. The results show improved collaborative experience and user engagement with the AI that can communicate. Moreover, the results shed light on emerging ethical concerns alongside increased user engagement. Inspired by the findings, this dissertation further explores the ethical challenges in human-AI co-creation by taking a human-centered approach. A design fiction study is presented to explore several ethical dilemmas and challenges in human-AI co-creation from the perspective of potential users. Findings provide potential users' perspectives, stances, and expectations, serving as a foundation for designing human-centered ethical AI partners in human-AI co-creation. Finally, this dissertation investigates users' mental models of co-creative AI, a crucial aspect of designing human-centered co-creative AI. A survey study is used to delve into users' mental models of co-creative AI and their association with user demographics to identify ways to design value-sensitive co-creative AI. The results also lay the groundwork for future research on personalized and adaptive co-creative AI in human-AI co-creativity.
Exclusive breastfeeding in the first six months of life and continued complementary breastfeeding up to 24 months is encouraged to ensure optimal infant and young child nutrition and health. The WHO and UNICEF emphasize these optimal Infant and Young Child Feeding (IYCF) practices, especially for regions of the world where extensive child nutrition and healthcare support is lacking or inaccessible.
This dissertation explores the epidemiology of IYCF practices and child health outcomes in sub-Saharan Africa. It also examines the status of IYCF policies and programs in this relatively less studied region of the world. I use publicly available data from the Nigerian Demographic and Health Survey (NDHS) and the WHO/UNICEF Breastfeeding Collective scorecard to answer important questions explored across three studies.
Findings from the first study suggest that longer durations of breastfeeding are associated with fewer reported acute illnesses post-infancy at 24 to 59 months; demonstrating the long-term protective effect of breast milk from illnesses that contribute to the high under-five mortality rates recorded for decades in sub-Saharan Africa. Another important finding from the second study is that the relationship between exclusive breastfeeding, household living environmental conditions, and acute health outcomes in infancy is complex. The results suggest that the efficacy of exclusive breastfeeding in reducing the incidence of diarrhea and acute respiratory illness is strongest for infants living in households with poor sanitation facilities and inadequate building materials respectively. Lastly, findings from the third study indicate that sub-Saharan Africa as a region is yet to meet global and World Health Assembly targets for the implementation of recommended IYCF policies and programs. These findings have implications for child nutrition and health outcomes in especially for a region already disproportionately impacted by high under-five mortality rates.
