ScholarWorks@UMassAmherst
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Recent Submissions
Publication NARRATIVES IN THE WRITINGS OF ENSLAVED BLACK WOMEN: THE CASE OF THE NEW KINGDOM OF GRANADA AND THE VICEROYALTY OF NEW GRANADA DURING THE 17TH AND 18TH CENTURIES(2024-05)This dissertation explores Black South American women and girls' epistolary tradition. Drawing on Black Feminist methodologies and decolonial theoretical frameworks/theoretical traditions, I analyze the intersections of race, class, gender, and sexuality and their effects on the creation, preservation, and analyses of Black women's early written production. Specifically, I center my analysis on bodies of literature composed of letters written by enslaved people alongside legal documents caused by Spanish colonial authorities. I explore the records of an enslaved Black woman produced in the context of lawsuits, legal battles, and cases of emancipation in the New Kingdom of Granada and the Viceroyalty of New Granada during the seventeenth and eighteenth centuries. I argue that the study of these often-overlooked documents contributes to the current conversations on the future of African studies, Black feminisms, Black women's literary production, Black anticolonial feminisms, and Black historiographies by shedding light on early written documents by enslaved women. This work highlights the importance of exploring these extensive bodies of literature and continuing to advance methodologies for analyzing this material by reading against the grain of the Trans-Atlantic colonial archives.Publication A Scalable Wear Leveling Technique for Phase Change Memory(2024)Phase Change Memory (PCM), one of the recently proposed non-volatile memory technologies, has been suffering from low write endurance. For example, a single-layer PCM cell could only be written approximately 108. This limits the lifetime of a PCM-based memory to a few days rather than years when memory-intensive applications are running. Wear leveling techniques have been proposed to improve the write endurance of a PCM. Among those techniques, the region-based start-gap (RBSG) scheme is widely cited as achieving the highest lifetime. Based on our experiments, RBSG can achieve 97% of the ideal lifetime, but only for relatively small memory sizes (e.g., 8–32GB). As the memory size goes up, RBSG becomes less effective and its expected percentage of the ideal lifetime reduces to less than 57% for a 2TB PCM. In this article, we propose a table-based wear leveling scheme called block grouping to enhance the write endurance of a PCM with a negligible overhead. Our research results show that with a proper configuration and adoption of partial writes (writing back only 64B subblocks instead of a whole row to the PCM arrays) and internal row shift (shifting the subblocks in a row periodically so no subblock in a row will be written repeatedly), the proposed block grouping scheme could achieve 95% of the ideal lifetime on average for the Rodinia, NPB, and SPEC benchmarks with less than 1.74% performance overhead and up to 0.18% hardware overhead. Moreover, our scheme is scalable and achieves the same percentage of ideal lifetime for PCM of size from 8GB to 2TB. We also show that the proposed scheme can better tolerate memory write attacks than WoLFRaM (Wear Leveling and Fault Tolerance for Resistive Memories) and RBSG for a PCM of size 32GB or higher. Finally, we integrate an error-correcting pointer technique into our proposed block grouping scheme to make the PCM fault tolerant against hard errors.Item Transcripts of Focus Group Data: Preparing Receiving Regions for a Just and Sustainable Climate Migration, Systems and Scenarios for New England(Univeristy of Massachusettes Amherst, 2024-08)Publication A Descriptive Approach to the Class NP(1997-02)Descriptive coraplexity is the study of the expressive power of logical languages. There exists a close relationship between the expressive power of a logical language and the computational complexity of the properties captured by such a language. R. Fagin proved that every sentence in second-order existential logic expresses a problem that can be decided by a non-deterministic polynomial time Turing machine: SOƎ = NP [9]. With this fact as our starting point, we study the sentences that express properties that are complete for the class NP via first-order projections (fops). This type of reductions arises naturally in descriptive complexity, and it is known that all problems complete for NP via fops are FO-isomorphic [1]. Our study of SOƎ sentences includes a normal form for sentences that describe NP-complete properties, the development of syntactic tools for proving problems NP-complete via fops, the definition of syntactic families of problems that have a similar syntactic structure, the study of the approximability of the problems in the syntactic families that we define, and a descriptive version of the POP theorem. This dissertation is organized in seven chapters. In Chapter 1, we present an overview of our research area and results. In Chapter 2, we review the concepts and definitions of descriptive complexity. In Chapter 3 we describe a normal form for SOB sentences that define a NP-complete problems via fops. In Chapter 4 we present syntactic tools to prove problems NP-complete via fops and use them to prove that a large number of the known NP-complete problems remain complete via fops. Among these tools, we define families of problems with similar syntactic structure. In Chapter 5, we study the approximation properties of some of the families defined in Chapter 4. In Chapter 6, we prove a descriptive version of the PCP theorem. This descriptive version implies both the PCP theorem in its computational version and Fagin's theorem. We close this work with Chapter 7 presenting our conclusions and suggestions for future research motivated by this dissertation.Item Bending-Driven Patterning of Objects in Lipid Membranes: Colloidal Assembly in Elastic1 2D Fluids(University of Massachusetts Amherst, 2024-07)
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