Dissertations and Theses
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Publication Avoiding A Never-Ending Heat Wave in Our Cities: A Spatio-Temporal Analysis of Vegetation and Temperature in Philadelphia(2025-05) Wang, Kelly; Jensen, ShaneAs Earth continues to warm, urban centers are struggling to disperse the additional heat that they are experiencing. Cities are not prepared for record-breaking temperatures in part due to their lack of natural vegetation that contribute to the urban heat island (UHI) effect. This study analyzes the spatial and temporal trends in land surface temperatures (LST) and vegetation across Philadelphia, Pennsylvania. This city has greening initiatives that plan to add green spaces to the built environment, intended to help mitigate the increasing heat. However, only a few studies have examined how changes in vegetation in cities, whether increasing or decreasing, have impacted the surface temperatures in its surrounding area over time. This paper uses data from Landsat 8's satellite imagery program to calculate a normalized vegetation index (NDVI) and surface temperatures aggregated at the Census block group level to analyze their relationship in over 1000 neighborhoods of Philadelphia over the years 2013--2022. The results of this paper indicate that there exists a strong negative relationship between LST and NDVI spatially and temporally.Publication Software-like Incremental Refinement on FPGA using Partial Reconfiguration(2024) Park, Dongjoon; DeHon, André; Li, JingTo improve FPGA design productivity, our goal is to create a development experience for FPGAsthat aligns closely with widely accepted software design principles. Software programmers quickly test their minimally completed design, identify the bottleneck, and incrementally refine the design. In FPGA design, however, such incremental refinement is not supported. (1) FPGA compilation is long, (2) a minor refinement leads to another long compilation, and (3) FPGA developers cannot easily identify a bottleneck of the design. We introduce a divide-and-conquer strategy in FPGA compilation, proposing a fast separate FPGA compilation using a Network-on-Chip (NoC) and Partial Reconfiguration (PR). This approach enables parallel and incremental FPGA compilation but requires users to manually decompose designs into operators that fit fixed-sized pages. In this thesis, we take the next step to support variable-sized pages using Hierarchical PR to provide flexibility to the users. With variable-sized pages, users can decompose a design naturally, without careful planning, enabling rapid hardware testing in a similar manner to how software programmers start testing with a minimally functional prototype. In addition, we propose a bottleneck identification scheme based on FIFO counters to provide profiling capability in FPGA design. Finally, we introduce a fast incremental refinement strategy that integrates our fast compilation framework and bottleneck identification scheme. The idea is to quickly map the design on the FPGA using the fast compilation framework and incrementally refine the design based on our bottleneck identification. The fast compilation with the NoC and PR pages iterates many initial yet important design points quickly, and for the final, optimized design, our strategy migrates to the monolithic system that does not have the area and bandwidth overhead of the NoC. Throughout the design tuning, we always have a hardware-mapped design whose performance we can measure to provide feedback to the users or automation script to identify the next bottleneck. We evaluate our fast incremental strategy with design tuning for realistic High-Level Synthesis applications. Our framework, fully compatible with AMD Vitis, achieves 1.3–2.7× faster tuning time than a monolithic flow where the vendor tool monolithically compiles each design point.Publication CROSS-COMPARTMENT IMMUNOLOGY OF PEDIATRIC NEUROINFLAMMATORY DISEASE(2024) Espinoza, Diego, Alexander; Bar-Or, AmitMultiple sclerosis (MS) and other demyelinating disorders are neuroinflammatory disorders arising from yet still incompletely understood immune-mediated mechanisms. Among MS disease-implicated mechanisms, roles for T cells and B cells have been identified across the immune compartments of the peripheral circulation, the central nervous system, and the secondary lymphoid tissues. Here, we dissect the roles that some of these disease-implicated immune cells play both in health and in disease across compartments, including the peripheral blood, the cerebrospinal fluid, and tonsillar tissue, with a focus on pediatric populations, a relatively understudied patient population where identified immune signatures may more closely reflect those mechanisms involved at the onset of disease. We also place emphasis on comparing identified signatures in MS to a more recently identified, similar demyelinating disorder known as myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) in order to derive more disease-specific insight. We first explore the heterogeneity of B cells within secondary lymphoid tissue in children without demyelinating disorders and identify a novel subset of CCL4/CCL4-expressing activated B cells alongside novel transcription factors putatively implicated in B-cell maturation. We next identify particular immune features of T cells and B cells distinguishing MS from MOGAD and other disorders, across both the cerebrospinal fluid compartment and the peripheral blood compartment,. Among our findings, we find that the presence of antibody-secreting cells is an MS-unique feature in pediatric-onset MS CSF across demyelinating disorders, and a skew towards VLA-4+ Th17 cell phenotype in the circulation of pediatric patients with MS distinguishes their immune profiles from patients with MOGAD. Taken together, our studies identify multiple immune mechanisms of T cells and B cells across health and disease, with potential new avenues identified for mechanistic studies and insight into targetable disease-implicated pathways.Publication The Decolonial Essay Film: Remapping Racial Capitalism from Diasporic Paris, 1968-1976(2024) Schlesinger, Matt; Barnard, Rita; Alekseyeva, JuliaThis dissertation examines critical, essayistic filmmaking practices developedby postcolonial migrants in Paris during the turbulent years following 1968. It focuses on several films which both emerged from and attempted to further migrant struggles over place-making in postcolonial Paris. Analyzing works by Med Hondo, Sidney Sokhona, Djouhra Abouda and Alain Bonnamy, I demonstrate that their hybrid, experimental works push spectators to critically reframe the socio-spatial dynamics of racial capitalism from the perspective of North and sub-Saharan African migrants, developing sophisticated aesthetico-political responses to postcolonial questions of migration, urban development and labor markets, diasporic identity, subjectivity and ideology, mobility regimes, and political resistance. I call these militant audiovisual interventions “decolonial essay films.ˮ The project calls for an interdisciplinary approach, engaging with recentstudies from (primarily Francophone) postcolonial studies; theories of racial capitalism; Marxist and Black geography; urban and mobility studies; and essayistic and diasporic/postcolonial film studies. Contextualizing these works within a wide range of political filmmaking practices, from the militant experimentations of Third Cinema to the rhythmic montages of Soviet city-films, I provide historically-situated close readings of Med Hondoʼs Soleil Ô (1970), Sidney Sokhonaʼs Nationalité: Immigré (1976), and Djouhra Abouda and Alain Bonnamyʼs Ali au Pays des Merveilles (1976). These works merit revisiting, as their sharp and generative visions remap the dynamics that still characterize our cities.Publication MITOCHONDRIAL NDUFA4 IS A FUNCTIONAL SWITCH CONTROLLING TUMOR-ASSOCIATED MACROPHAGES AND TUMOR IMMUNITY(2024) Clark, Megan, Lynn; Henao-Mejia, JorgeTumor-associated macrophages (TAMs) play a critical role in the clinical outcome of solid tumors and the efficacy of immune checkpoint blockade (ICB) therapies. Interferon (IFN)-TAMs are a potent immunostimulatory TAM subset recently identified in several human cancers, with higher frequencies strongly predicting improved overall survival and ICB responses. Yet the molecular mechanisms governing IFN-TAM gene expression programs and population dynamics remain largely unknown. Herein, we uncover a mitochondrial process where NDUFA4, a subunit of Complex IV of the electron transport chain, serves as a switch that controls TAM functions and tumor immunity. We demonstrate that in response to interferons (IFNs) within the tumor microenvironment, NDUFA4 is dramatically downregulated in TAMs by the cooperative activity of the NDUFA4 homolog NDUFA4L3 and the microRNA miR-147, both encoded by a single highly conserved bifunctional transcript. Notably, repression of NDUFA4 is necessary for the expansion of IFN-TAMs and subsequent anti-tumor immunity via NK and CD8+ T cell recruitment, whereas constitutive NDUFA4 expression supports pro-tumoral TAMs. Unexpectedly, we find that NDUFA4 minimally contributes to mitochondrial respiration but instead primarily functions as a gatekeeper of mitochondrial DNA (mtDNA) release into the cytoplasm. Consequently, NDUFA4 repression enhances mtDNA-induced stimulator of interferon genes (STING) activation, thereby amplifying anti-tumor IFN-induced transcriptional programs in TAMs. Finally, leveraging the exceptional specificity of miR-147 for the Ndufa4 transcript, we demonstrate that RNA-based therapeutics targeting this functional switch enhance ICB efficacy and inhibit tumor growth. In summary, we uncover that tumor microenvironmental cues control the abundance of IFN-TAMs and subsequent anti-tumor immunity through the regulation of NDUFA4 and that this novel functional switch can be exploited for cancer immunotherapies.