Dissertation Defense Announcements

Due to the shortage of World Language and English as a Second Language teachers, recruiting, retaining, and supporting aspiring second language teachers in the completion of their teacher licensure program is crucial. One barrier to the profession for these teachers is edTPA. Research has suggested that non-native English speakers (NNES) who populate second language teacher preparation programs may struggle to complete this assessment more so than their native-English speaking (NES) peers. To shed light on this topic, the researcher used a mixed methodology to examine the performance, perceptions, and preparation of NNES and NES teacher candidates on the World Language and English as an Additional Language edTPA. Data sources included edTPA scores, survey responses and faculty interviews.

The study’s results suggest that the performance of NNES candidates may vary by their teaching assignment and corresponding edTPA portfolio to complete. The results also revealed that NNES candidates’ perceptions centered on their struggles with the writing requirements for edTPA and their lack of awareness of the assessment’s expectations and its connections to coursework. Both candidates and faculty mentioned the benefits of practice edTPA tasks infused in coursework and content-specific seminars offered during the internship. The use of customized language support such as peer editing and the use of other writing resources was reported by candidates and faculty to be especially beneficial for NNES candidates. The study’s findings serve to inform teacher preparation programs as they strive to improve the edTPA preparation of all candidates, including those whose first language is not English.

Diverse and alternative forms of economies have recently gained increased attention for their potential to transform conceptually and empirically the mainstream economic system. Around the world, scholars have documented the emergence and impact of economic practices that do not necessarily align with the principles and functioning mechanisms of the capitalist system. However, to this date, little is known about the contribution of migrant communities to diverse collaborative economic practices as they increasingly play a significant socio-economic role in the United States. This dissertation research relies on a postructuralist and postcolonial conceptualization of the economy as a diverse, contested, and situated realm to produce nuanced understandings of diverse economic practices developed by migrant communities in the US and to fill in the gaps of current understandings of diverse economies, ethnic economies, and ethnic foodscapes. This exploratory study relies on a relational comparative case study to investigate three dimensions of Latinx food-based collaborative practices (individual, collective, and contextual) in two urban contexts in the US – Boston (MA) and Charlotte (NC). By relying on a mixed-method approach in each context of study, this dissertation demonstrates the existence of multiple, diverse, and intertwined food-based collaborative networks assembled through the enactment of economic practices and informed by values of solidarity, interdependence, and cooperativism rooted in Latinx individuals’ non-static identity, cultural background, and past experiences. It also shows the heterolocal spatial form of food-based collaborative networks in the two contexts of study and the extension of their constitutive relational linkages across non-hierarchical scales. Finally, it demonstrates the mutually constitutive relationships between Latinx food-based diverse economic practices and the contexts in which they emerge, alongside the important transformative power these practices have for individuals, groups, and the context. Through this research I extend ontological economic value to diverse food-based collaborative economic practices and show how these Latinx communities are already diversifying the economy in highly capitalist contexts, such as the United States, and, more importantly, are already assembling the conditions to develop more sustainable economic scenarios.

National mathematics achievement results show elementary students in the United States are not increasing in cognitive ability or critical thinking skills (NAEP, 2019). Furthermore, students who are mathematically promising need more opportunities for cognitively demanding mathematics instruction in order for this increase to occur. Therefore, this descriptive case study focused on the interactions and emergence of Mathematical Practices in seven third grade students with a series of five tasks. The seven third grade students were identified by their teachers as mathematically promising. The tasks used in the two suburban classrooms observations of the study were from the Tools 4 NC teachers framework (Tools 4 Teachers, 2019). Data sources collected included pre- and post-focus group audiotapes, classroom observations via audio and video, field notes, as well as document analysis of student work and a teacher debrief form. Blumer's theory of social constructivism (1969) and Tripathi’s Multiple Reasoning (2008) guided this study.

Findings from the students' interactions with tasks showed the following themes: students used a variety of interpersonal interactions between themselves, the teacher, and visual representations. Students used mathematical writing to justify their reasoning and reflection to communicate their conceptual mathematical understanding. Students grew in their emergence of the Mathematical Practices of perseverance through problem solving, productive struggle, the construction of arguments, and the ability to make connections. These findings indicate the importance of ongoing curriculum development to include differentiated teacher guidance for mathematically promising students. Additionally, the findings of this study will support mathematics teachers and leaders with a student-centered approach to teaching inquiry-based instruction.

This work presents new protection methods for addressing challenges related to integrating a fully inverter-based generation resource microgrid into the power distribution system. Renewable-energy-sourced microgrids offer promise in providing sustainable energy solutions to meet energy needs. Most of the widely used renewable resources and energy storage systems are interfaced with the power grid through power electronic devices, such as inverters. Diverse expertise is required for the design, construction, and operation of an inverter-based microgrid (IBMG). First, this dissertation provides a comprehensive overview of IBMG characteristics and highlights key obstacles in the design of these systems. The difference between the response of inverter-based resources and synchronous machine-based resources and the dependency of inverter response on its control modes are discussed. Second, a method for distribution system short circuit study considering inverter-based distributed generation is designed. Third, an Electromagnetic Transient (EMT) based inverter modeling for grid following and grid forming mode for both balanced and unbalanced distribution systems is proposed. Fourth, a method is proposed for controlling transient overvoltage in a microgrid-integrated power distribution system. Finally, a new protection method for detecting faults in an IBMG system helps to address the well-known issue of microgrid protection sensitivity and selectivity. The effectiveness of the overall framework is tested with small test systems and large IEEE test systems with relevant data sets. The studies show that the proposed approaches can improve the IBMG system design and increase the reliability of such systems.