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Value Function Approximation Algorithms for Reinforcement Learning in Delay-Sensitive Wireless Communications
No full textPh.D.Recent advances in the energy-harvesting techniques has enabled wireless sensors capable of harvesting ambient energy from the environment to be employed in quality-of-service (QoS) sensitive applications. In this dissertation, we focus on studying the performance limits and characterize the optimal policies of such sensors employed in delay-sensitive and power constrained applications. We consider an energy harvesting sensor transmitting latency-sensitive data over a fading channel. We aim to find the optimal transmission scheduling policy that minimizes the packet queuing delay given the available harvested energy. We formulate the problem as a Markov decision process (MDP) over a state-space spanned by the transmitter’s buffer, battery, and channel states, and analyze the structural properties of the resulting optimal value function, which quantifies the long-run performance of the optimal scheduling policy. We show that the optimal value function (i) is non-decreasing and has increasing differences in the queue backlog; (ii) is non-increasing and has increasing differences in the battery state; and (iii) is submodular in the buffer and battery states. Taking advantage of these structural properties, we derive an approximate value iteration algorithm in the offline scenario, that considers a priori knowledge of the channel and traffic dynamics, and a reinforcement learning (RL) algorithm in the online scenario, without any a priori knowledge of the system dynamics, that provide a controllable tradeoff between approximation accuracy, computational complexity, and memory. We prove that the algorithms converge to a near-optimal value function and policy. Our numerical results confirm these properties and demonstrate that, in the offline case, the resulting scheduling policies outperform a greedy policy in terms of queuing delay, buffer overflows, energy efficiency, and sensor outages; and, in the online case, the RL algorithm achieves competitive performance relative to an efficient state-of-the-art algorithm in terms of queuing delay, energy occupancy, etc., and outperforms the well-known Q-learning algorithm. In conjunction with these algorithmic advances, we also propose an efficient hardware accelerator framework to improve the performance of a state-of-the-art RL algorithm by speeding up the action evaluation step, which represents the computational bottleneck of the algorithm. We demonstrate the benefits of our approach through extensive experimental results, where we observe around 50× improvement in speed relative to the standard un-optimized version of the state-of-the-art algorithm, and over 6×improvement compared to the well-known Q-learning algorithm.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Computational Modelling and Simulation of RF Induced Heating of Biological Tissue
No full textM.S.Radio Frequency waves are electromagnetic waves in the range of frequency 30 kHz to 300 GHz. They are being used extensively in multiple medical applications with perhaps the most remarkable being in the medical imaging modality of Magnetic Resonance Imaging (MRI). As the desire to use MRI of increasingly higher magnetic field strengths persists, RF waves of corresponding higher frequencies are being used. Even though RF waves are non-ionizing in nature and generally harmless but the exposure of biological tissues to high RF power can have other negative implications. The most significant manifestation of RF energy absorption by live tissues is the increase in temperature of the tissue which could lead to permanent damage and discomfort. Hence, it is particularly important to study the effects of RF induced tissue heating. Alternatively, the phenomenon of tissue heating is utilized in hyperthermic tissue ablation to thermally destroy cancerous cells with highly localized, controlled application of RF energy or Microwave. With computational techniques like Finite Element Analysis (FEA), it has become easy to model and simulate the heating of biological tissues under different exposure scenarios. In this thesis, the effect of 5 different MRI RF frequencies (63.87 MHz, 127.5 MHz, 170 MHz, 200 MHz, and 300 MHz) on the heating patterns of biological tissue are stimulated in COMSOL Multiphysics. Additionally, the pattern of thermal ablation of cancerous liver tissue at 1 GHz and 2.5 GHz is also modeled.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Bond Strength of Luted Zirconia and Titanium Using Different Resin Cements
No full textM.S.Background: The success of implant-supported prostheses has been a major milestone in clinical dentistry. However, bonding the zirconia (ZrO2) ceramic component of the two-piece abutments to the titanium (Ti base) by luting agents creates concern regarding the debonding and the longevity of two-piece abutments. The purpose of this study is to evaluate the impact of different resin cements on the bond strength of luted titanium to zirconia and evaluate the impact of shaded and non-shaded zirconia on the bond strength of luted titanium to zirconia. Materials and Methods: Sixty milled titanium (Ti-6Al-4V) cylinders were prepared with a series of abrasive papers (ending in 1200 grits) and polished with diamond slurry. A titanium base was scanned, and the surface area was measured to determine its bonding area. Then thirty non-shaded zirconia and thirty shaded zirconia were milled to cylinders of 8 mm diameter x 5 mm high. The bonding surfaces were abraded with 50 µm Al2O3 particles. Titanium cylinders were randomly separated into three groups of twenty. Each group was assigned to a resin cement. Then, each group was divided into two subgroups, 10 each, according to the zirconia shade. All specimens were subjected to thermal cycling for 1000 cycles, followed by the application of shear force at the bond interface using a universal testing machine (MTS). Two-way ANOVA, Tukey HSD tests, and Levene’s tests were used for statistical analysis of the shear bond strength data (α = .05).Results: Multilink Hybrid provided a significantly higher bond strength compared to Panavia V5 (p = .001). Non-shaded zirconia showed higher bond strength than shaded zirconia, but the differences were not statistically significant. Conclusion: Resin cement selection does have an impact on the bond strength between titanium and zirconia. Also, zirconia shade does not impact the bond strength between titanium and zirconia.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Lunar Love and Asynchronous Aestheticism: Vasily Rozanov's People of the Moonlight and Dmitry Frolov's Experimental Films in Post-Soviet Russia
No full textM.A."Lunar Love and Asynchronous Aestheticism: Vasily Rozanov's People of the Moonlight and Dmitry Frolov's Experimental Films in post-Soviet Russia" examines the ways in which the Silver Age influences the depiction of homosexuality in the post-Soviet cinema and literature. It focuses on Vasily Rozanov's ideas as formative for the filmmaker Dmitry Frolov and authors Aleksandr Ilyanen and Dmitry Bushuev. The thesis argues that aestheticism and retrospection define the homoerotic art of post-Soviet Russia. Frolov's experimental films that explore homoeroticism achieve aesthetic and conceptual asynchronicity as cinematic objects and in terms of their inner diegetic temporality. The analysis of Frolov's homoerotic films as having Russian etiology and specificity contributes to queer film historical scholarship.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Facile Formulation of a Long-Wavelength Cyanine for Optical Imaging in the Second Near-Infrared Window
No full textM.Eng.The second near-infrared window (NIR-II) beyond 1000 nm has attracted attention for optical contrast imaging in animals. It was sought to assess whether commercially available NIR-II dyes could be easily formulated for this purpose. 13 hydrophobic NIR-II dyes were purchased and screened by formulating them in simple solubilization systems with established use in humans: Propylene glycol, Cremophor EL, Kolliphor HS15, Tween 80, and cyclodextrin. Based on the absorption at 1064 nm (matching the Nd:YAG laser output commonly used in photoacoustic imaging), 3 of the dyes were futher assesed at varying dye and surfactant concentrations. Of these, benzo indole butyl diphenylaminocyclopentene heptamethine (BIBDAH) tetrafluoroborate in HS15 generally showed the most favorable NIR-II character. 1 mg/mL BIBDAH in 25 % HS15 exhibited a single absortion peak at 1030 nm with a calculated intensity greater than 100, which was relatively stable for weeks in storage. Following intravenous administration to mice, direct determination of BIBDAH pharmacokinetics was possible by absorption measurements of sampled plasma, revealing a circulating half-life of about one hour. Most of the dye was taken up by the liver. BIBDAH was used in vitro and in vivo as a photoacoustic contrast imaging agent and its accumulation could be detected in subcutaneous tumors in mice. BIBDAH was also used for fluorescence imaging of blood vessels in mice, including in the brain (through intact skull), and dye clearance from blood to the liver was visualized. Taken together, this study confirms that accessible, strongly-absorbing dye can readily be formulated for injection by simply dissolving them in biocompatible surfactants and used high-contrast preclinical optical imaging in the second NIR window.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Study of High-Mannose Glycan Truncation on von Willebrand Factor (VWF)
No full textM.S.Von Willebrand factor is a large multimeric plasma glycoprotein that plays a key role in maintaining hemostasis and thrombosis. Quantitative and functional deficiency in VWF, majorly inherited, lead to a condition called von Willebrand disease (VWD). Recent advances in biopharmaceuticals has paved way for the supplementation of recombinant VWF to treat VWD. VWF is heavily glycosylated and makes it vital to study the role of these glycans in protein function and half-life. Previous studies have shown that reducing high-mannose N-glycans by genetic methods or using chemical inhibitors increases VWF half-life circulation. In this study, we biologically expressed endoglycosidase H (EndoH) both transiently and stably within mammal cells while simultaneously producing recombinant VWF in them. Endo H truncates high-mannose N-glycans on glycoproteins at the chitobiose core leaving behind a GlcNAc attached to the protein at Asn. We want to ensure that the structural property of VWF is not disturbed by truncation of high-mannose glycans on its surface. Also, the lectins on the stably expressing EndoH (ShE1) cell line were studied to understand the EndoH protein activity.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Heterostructures Consisting of Vanadium Oxide Nanowires, With or Without Intercalated Cations, Interfaced with Cadmium Chalcogenide Quantum Dots: Investigating Band Energetics for More Efficient Charge-Transfer Processes
No full textPh.D.Heterostructures consisting of either vanadium oxide nanowires (V2O5 NWs) or metal vanadium bronze nanowires (MxV2O5 NWs) interfaced with quantum dots (QDs) are interesting architectures for light harvesting, excited-state charge transfer, and solar energy conversion. This dissertation will explore both charge-transfer dynamics and thermodynamic offset effects for these heterostructures. Chapters 2, 3, 4, 6, and 7 of this dissertation focus on heterostructures comprising β-MxV2O5 (M= intercalated metal cations, Pb2+ or Sn2+) interfaced with CdE (E=S/Se/Te) QDs. Chapter 5 focuses on the heterostructures comprising α-V2O5 NWs interfaced with CdE QDs. These chapters will report on programmable energetic offsets for photogenerated charge separation, and subsequent further separation through the addition of additional charge-transfer pathways...**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
A Posthumanist Challenge to Mass Incarceration: Criminals Aren't a Thing
No full textM.A.In this thesis, I make the claim that criminals don't exist; instead, they performatively emerge through an ongoing set of material-discursive conditions that sustain the current distributions of racial capitalism. Over the last 40 years, the U.S. criminal legal system has been increasingly intent on selective incapacitation, a theory that most crime is committed by a select group likely to be repeat offenders. The desire to seek out criminals among us has led to efforts to better measure and predict criminality. These efforts have been augmented and accelerated by the use of predictive algorithms in police profiling and, the focus of this thesis, in sentencing. I argue that sentencing algorithms, rather than providing an epistemic tool to more accurately predict who is a criminal while simultaneously eliminating racial and gender bias, contribute to the mistaken metaphysical claim that criminals are discovered rather than produced. I use Karen Barad's alternative framework of "agential realism" to inform a posthumanist reading of one of the most popular sentencing algorithms, COMPAS. In doing so, I challenge the metaphysics of individualism that enables faith in the bifurcation of knowing/being and the Cartesian divide between subject/object that structure a belief that technological solutions can provide access to universal and objective truth. I demonstrate how shielding reason and rationality from the heart of current critiques of sentencing algorithms conceals raced and gendered assumptions. Finally, I argue that the logic that structures the possible horizon of legal challenges to COMPAS contributes to the construction of the criminal. The law—through its association of criminality and risk with certain behaviors, feelings, and bodies—articulates what is free, modern, and civilized while simultaneously regulating access to those goods. As a result, the law, and criminal justice practices permitted by it, participate in the production of time, space, and corporeality.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
A Study of Grit and Self-Regulation in Students, Instructor Effectiveness, and Purposeful Course Design of Asynchronous Online Statistics Courses in Higher Education
No full textPh.D.This study analyzed the impact that student characteristics (i.e., grit and self-regulation), instructors' characteristics and course design in an asynchronous online college statistics course had on student achievement. In order to determine the impact on student achievement, students enrolled in eight sections of Introductory Statistics 1 course for four semesters at a local community college completed Pre- and Post-Course surveys. Furthermore, the two instructors were both interviewed and a review of the asynchronous online course design was performed using the OSCQR rubric. This study determined that grit significantly impacted student achievement while self-regulation had minimal effect. Instructors' characteristics found to be significant in student achievement included empathy, pedagogy and leader-by-example. These characteristics were those that resonated throughout the instructors' interviews. The course design of the asynchronous online course, Introductory Statistics 1, for this study was found to be in good standing for five of the six standards on the OSCQR rubric. The one standard that was lacking was interaction. Even though students interacted in discussion board assignments, both course designs lacked enriching opportunities for rich and robust interactions between students; and between the instructor and students; that would build a community of learners. This study is particular needed given the fact that most higher education institutions now offer many courses in some form of asynchronous online modality.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
The Child Sex Scandal and Modern Irish Literature: Writing the Unspeakable
No full textIncludes bibliographical references and index.This book is freely available in an open access edition thanks to TOME (Toward an Open Monograph Ecosystem)—a collaboration of the Association of American Universities, the Association of University Presses, and the Association of Research Libraries—and the generous support of the University at Buffalo Libraries. Learn more at the TOME website, available at: https://www.openmonographs.orgEven though the Irish child sex abuse scandals in the Catholic Church have appeared steadily in the media, many children remain in peril. In The Child Sex Scandal and Modern Irish Literature, Joseph Valente and Margot Gayle Backus examine modern cultural responses to child sex abuse in Ireland. Using descriptions of these scandals found in newspapers, historiographical analysis, and 20th- and 21st-century literature, Valente and Backus expose a public sphere ardently committed to Irish children's souls and piously oblivious to their physical welfare. They offer historically contextualized and psychoanalytically informed readings of scandal narratives by nine notable modern Irish authors who actively, pointedly, and persistently question Ireland's responsibilities regarding its children. Through close, critical readings, a more nuanced and troubling account emerges of how Ireland's postcolonial heritage has served to enable such abuse. The Child Sex Scandal and Modern Irish Literature refines the debates on why so many Irish children were lost by offering insight into the lived experience of both the children and those who failed them.Introduction: The enigmatic history of imperiled innocence --
"An iridescence difficult to account for" : sexual initiation in Joyce's fiction of development --
Between (open) secret and enigma : Kate O'Brien, The land of spices, and the stylistic invention of lesbian (in)visibility --
Country girl : groomed, seduced, and abandoned --
From the pits and ditches where people have fallen : sex scandal and the reinvention of the Irish public sphere in Keith Ridgway's The long falling --
Retrofitting Ireland's architecture of containment in Tana French's In the woods --
"Roaring inside me" : the enigma of sexual violence in The gathering --
Epilogue: What about Brendan