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Studying urban dynamics is essential given the ever-increasing changes in urban areas with all its ensuing consequences, whether negative or positive. It is of paramount importance to take into account the temporal dimension of urban dynamics when studying its patterns and processes. Nevertheless, the majority of studies overlook this consideration and take cross-sectional research approaches. Moreover, a large body of literature in urban dynamics is dedicated to the explanatory analysis and causal inference only, neglecting the importance of predictive analysis. Addressing these two main gaps, this research explores urban dynamics through both causal inference and predictive modeling using longitudinal research designs. Urban dynamics are studied from two aspects in this work; transportation/land-use interactions, and economic growth. In the first article, the impact of built environment on commuting duration is assessed in 2000 and 2015 in Mecklenburg County, NC using spatial panel data models. Results show that the built environment has a statistically significant impact on commuting duration. However, it is important to note that the practical magnitude of the impact is small. In the second and third articles, the business performance of businesses are forecasted for non-business services and business services respectively in Mecklenburg County, NC, using recurrent neural networks long short-term memory deep learning method. After building and training the sequential model, its predictive performance is assessed using out-of-sample evaluation.
With the rapid increase in connected devices and SoC design architecture being used in diverse platforms, they become potential targets to gain unauthorized access for data and privacy invasion. Therefore, heterogeneous SoC architecture raises security concerns in addition to the benefits they offer with improved throughput. They are susceptible to side-channel attacks where secure information is extracted through communication channels. Crypto algorithms implemented for secure authentication tend to leak sensitive information jeopardizing system security. Memory corruption vulnerabilities, code injection, buffer overflow attacks and other software-based attacks through untrusted channels tend to control the flow of the application with malicious data. Though traditional defense mechanisms have been implemented, they are still vulnerable to side-channel attacks. Secure measures to protect the interfaces and data propagation through different channels are critical and building a resilient model consists of the on-chip security factors. In this work, a platform-based SoC model is implemented to meet the security objectives using the RISC-V architecture. An information flow tracking module tracks the flow of data for the system’s integrity along with crypto engines and a secure boot mechanism for secure device authentication providing encrypted data transfers. For bitstream resilient SoC models the work extends a logic obfuscation module with runtime security leading to a secure assessment framework. This work explores the microarchitectural side-channel attacks with machine learning models.
This dissertation is focused on developing efficient numerical methods and theoretical analysis for solving various inverse problems that arise in the fields of mathematics, physics, engineering, and beyond. We propose in this dissertation a unified framework with two stages to solve severely ill-posed and highly nonlinear inverse problems. In the first stage, we derive a system of partial differential equations by introducing a new variable and truncating the Fourier series of the solution to the governing equation. In the second stage, we solve the system derived in the first stage using the quasi-reversibility method, the Carleman contraction mapping method, and the convexification method. The obtained solutions of this stage directly yield the desired solutions to the inverse problems. An important contribution of the dissertation is that we will rigorously and numerically prove the efficiency of this framework, including its global convergence to the true solution. The analytic proofs are based on some Carleman estimates, and the numerical proofs are provided by successfully testing our methods with highly noisy simulated data and experimental data provided by US Army Research Laboratory engineers.
This dissertation focuses on developing efficient numerical methods and theoretical analysis for solving various inverse problems that arise in mathematics, physics, engineering, and beyond. We propose in this dissertation a unified framework with two stages to solve severely ill-posed and highly nonlinear inverse problems. In the first stage, we derive a system of partial differential equations by introducing a new variable and truncating the Fourier series of the solution to the governing equation. In the second stage, we solve the system derived in the first stage using the quasi-reversibility method, the Carleman contraction mapping method, and the convexification method. The obtained solutions of this stage directly yield the desired solutions to the inverse problems. An important contribution of the dissertation is that we will rigorously and numerically prove the efficiency of this framework, including its global convergence to the true solution. The analytic proofs are based on some Carleman estimates. The numerical proofs are provided by successfully testing our methods with highly noisy simulated data and experimental data provided by US Army Research Laboratory engineers.
Students in urban schools face a number of challenges including lower enrollment numbers in higher level mathematics courses. This particular challenge has the drastic consequence of increasing the achievement gap and reducing the opportunities available for Black students. Traditionally schools have utilized standardized tests and teacher input to determine placement into these higher level mathematics courses. This research study was a qualitative study designed to focus on the perceptions of middle school principals who have had success in reducing the underrepresentation of Black male students in higher level mathematics courses. Data was collected through semi-structured interviews with successful middle school principals in North Carolina. This research serves to provide insight into what practices middle school principals identify for schools to implement in order to lessen the underrepresentation of Black male students in higher level mathematics courses.
Keywords: underrepresentation, student achievement, assessment
The term “kindergarten readiness” lacks a formal definition. This study was done to understand the perceptions of preschool and kindergarten teachers concerning typically developing students on day 60 of kindergarten. Focus groups were used to determine particular skills that a kindergartener should exhibit by that point in school in order to be successful during that year. Both groups of teachers were knowledgeable about the developmental continuum kindergartners should follow in order to achieve needed skills. A second finding was that kindergarten teachers scored students lower than preschool teachers on the anticipated ability of their students to achieve a skill. All teachers considered some skills were introduced prematurely. Kindergarten readiness can be described as skills that students should exhibit on day 60 of kindergarten in order to be successful. These include having control of their emotions, and understanding the emotions of others and what may cause them. Students on day 60 of kindergarten should also understand how to behave in familiar environments and when routines and procedures did not change. Further, they should be able to discriminate the sound that an alliteration and rhyme make but may not be able to explain the reason for the alliteration or rhyme.
Safety, often understood as freedom from unacceptable loss, and reliability, the capacity to accomplish particular outcomes repeatedly through operational sensitivity, are compelling performance objectives for high-risk organizations. If either is absent, people, organizations, and their external environments are potentially at unnecessary risk. Focused on continuous performance improvement, debriefs are team meetings that are often implemented to enable safe, reliable outcomes in these settings through post-incident discussion. Historically, research has presumed debriefs to support the capacity of teams to pursue the twin objectives of safety and reliability simultaneously without contradiction. However, this theoretical assumption has never been assessed according to how a team’s discourse in debriefs constitutes safety and reliability as distinct outcomes. This research adopts Craig and Tracy’s (2021) grounded practical theory methodology to analyze talk in post-competition debriefs among stock car racing pit crews. Analysis framed debrief participants’ talk according to problem and technical levels of grounded practical reconstruction, suggesting a central dilemma that constrains pit crews’ efforts for safety and reliability in these meetings, namely a contradiction among performance expectations for regulatory adherence and for boundary pushing. Results also feature several discursive techniques that pit crews employ during debriefs in response to this dilemma. A model of dilemmatic talk in debriefs situates these outcomes in the context of fragility, an implicit value of this complex, dynamic work environment made explicit.
The term “kindergarten readiness” lacks a formal definition. This study was done to understand the perceptions of preschool and kindergarten teachers concerning typically developing students on day 60 of kindergarten. Focus groups were used to determine particular skills that a kindergartener should exhibit by that point in school in order to be successful during that year. Both groups of teachers were knowledgeable about the developmental continuum kindergartners should follow in order to achieve needed skills. A second finding was that kindergarten teachers scored students lower than preschool teachers on the anticipated ability of their students to achieve a skill. All teachers considered some skills were introduced prematurely. Kindergarten readiness can be described as skills that students should exhibit on day 60 of kindergarten in order to be successful. These include having control of their emotions, and understanding the emotions of others and what may cause them. Students on day 60 of kindergarten should also understand how to behave in familiar environments and when routines and procedures did not change. Further, they should be able to discriminate the sound that an alliteration and rhyme make but may not be able to explain the reason for the alliteration or rhyme.
Although significant research has been conducted on opportunity gaps between White and racially minoritized students, the percentage of minority students has reached 53% of the United States K-12 public schools (NCES, 2022). While the percentage of minority students now constitute the majority of public schools, the teacher workforce and school leadership remains majority White. As such, there is a need for additional investigations examining the role of culturally responsive classroom and school leadership practices in public schools. In particular, in the research, less is known about African American males and their culturally responsive school leadership practices. Thus, this study uses autoethnography to explore the experiences of a Black male school leader and the role of culturally responsive school leadership (CRSL) and conscientization in promoting effective school practices. As a member of a minority group, the school leader had relevant life and educational experiences of struggles and triumphs that impacted his leadership practices. These practices included but are not limited to fostering empathy, care, relevance, and rigor, which impacted the overall school climate and achievement. With the use of these practices that are grounded in CRSL, this urban school outperformed schools in the neighboring district. In sum, the findings suggest that there remains a need for more investigations on the role of CRSL in promoting urban school success.
