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Title: HIGH ENERGY SODIUM BASED ROOM TEMPERATURE FLOW BATTERIES
Creator: Shamie, Jack
Date: 2015, 2015-12
Description: As novel energy sources such as solar, wind and tidal energies are explored it becomes necessary to build energy storage facilities to load...
Show moreAs novel energy sources such as solar, wind and tidal energies are explored it becomes necessary to build energy storage facilities to load level the intermittent nature of these energy sources. Energy storage is achieved by converting electrical energy into another form of energy. Batteries have many properties that are attractive for energy storage including high energy and power. Among many di erent types of batteries, redox ow batteries (RFBs) o er many advantages. Unlike conventional batteries, RFBs store energy in a liquid medium rather than solid active materials. This method of storage allows for the separation of energy and power unlike conventional batteries. Additionally ow batteries may have long lifetimes because there is no expansion or contraction of electrodes. A major disadvantage of RFBs is its lower energy density when compared to traditional batteries. In this Thesis, a novel hybrid Na-based redox ow battery (HNFB) is explored, which utilizes a room temperature molten sodium based anode, a sodium ion conducting solid electrolyte and liquid catholytes. The sodium electrode leads to high voltages and energy and allows for the possibility of multi-electron transfer per molecule. Vanadium acetylacetonate (acac) and TEMPO have been investigated for their use as catholytes. In the vanadium system, 2 electrons transfers per vanadium atom were found leading to a doubling of capacity. In addition, degradation of the charged state was found to be reversible within the voltage range of the cell. Contamination by water leads to the formation of vanadyl acetylacetonate. Although it is believed that vanadyl complex need to be taken to low voltages to be reduced back to vanadium acac, a new mechanism is shown that begins at higher voltages (2.1V). Vanadyl complexes react with excess ligand and protons to reform the vanadium complex. During this reaction, water is reformed leading to the continuous cycle in which vanadyl is formed and then reduced back to the original state. In the discharged state, it was found that precipitation occurs, but is due to solubility limits and not chemical reactions. The TEMPO system showed the potential of higher concentration catholytes although large capacity losses were found. Although no explanation is found, the behavior of the fade is related to time and concentration.
Ph.D. in Mechanical, Materials and Aerospace Engineering, December 2015
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Title: Serostatus Disclosure as a Predictor of Metal Health and Physical Health Among HIV-Seropositive Adults
Creator: Niel, Kristin
Date: 2011-05-09, 2011-05
Description: As estimated 1,200,000 people in the United States were living with HIV in 2009 (UNAIDS, 2010). African Americans have an incidence rate seven...
Show moreAs estimated 1,200,000 people in the United States were living with HIV in 2009 (UNAIDS, 2010). African Americans have an incidence rate seven times that of Caucasians. Research has shown that HIV-positive people have high levels of psychological distress (Cook et al., 2006); depression is the most frequently diagnosed disorder (Treisman, Angelino, & Hutton, 2001). Distress negatively impacts physical health (Comer, Henker, Kemeny, & Wyatt, 2000; Cruess et al., 2005) and medication adherence (Cook, et al., 2006; Mellins et al., 2002) in HIV-positive patients. Although disclosure of HIV-seropositivity can lead to increased social support (Armistead, Morse, Forehand, Morse, & Clark, 1999), it may also lead to social rejection, prejudice and increased distress (Cederfjall, Langius-Eklof, Lidman, & Wredling, 2001; Kalichman, DiMarco, Austin, Luke, & DiFonzo, 2003). This study examined 110 HIV-positive patients at an urban medical clinic. Patients completed self-report measures as part of a larger study investigating posttraumatic growth in HIV/AIDS. It was hypothesized that (a) more participants would disclose to friends and partners than to family; (b) participants who disclosed to more people would endorse fewer symptoms of distress; and (c) participants who disclosed to fewer people would be less likely to adhere to medical regimens and routinely attend medical appointments, and have poorer health outcomes. Distress was measured by Psychiatric Symptom Index (PSI), Beck Depression Inventory (BDI), and the Impact of Event Scale (IES). Viral load and CD4 cell counts were found in medical charts, and the AIDS Clinical Trails Group Adherence Follow-up Questionnaire measured adherence. Analyses reveal that 67.3% of participants disclosed to family, 55.5% to at least one partner, and 45.5% to friends. A negative association existed between full disclosure and IES Avoidance scale (r = -.20, p< .05). There were positive associations between disclosure to family and the PSI Depression Scale (r = .22, p < .05), Cognitive Disturbance Scale (r = .21, p < .05), and PSI Total Score (r = .22, p < .05), implying that disclosure to more groups of people may be associated with increases in psychological distress ratings. Implications of these findings are discussed.
M.S. in Psychology, May 2011
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Title: A THERMAL RESISTANCE STUDY OF SHIGA TOXIN-PRODUCING ESCHERICHIA COLI (STEC) IN LOW MOISTURE FOOD WITH THE USE OF A DIFFERENTIAL SCANNING CALORIMETER (DSC)
Creator: Liu, Shi
Date: 2014, 2014-12
Description: According to CDC's Foodborne Disease Outbreak Surveillance System database, from the years 2007-2011, there were eight outbreaks associated...
Show moreAccording to CDC's Foodborne Disease Outbreak Surveillance System database, from the years 2007-2011, there were eight outbreaks associated with low-moisture food including nuts, cheese, cookie dough, and wheat snack food involving Shiga toxinproducing Escherichia coli O157:H7 (STEC), which led to over 318 cases of foodborne illnesses. Yet, insufficient data on STEC thermal inactivation has been obtained in lowmoisture food. In this study, a novel methodology using a Differential Scanning Calorimeter was used to measure STEC thermal inactivation kinetics in low moisture environments. The objective of this study was to use a Differential Scanning Calorimeter to measure D- and z-values, and therefore to determine the microbial thermal resistance, of select STEC strains. Five strains of outbreak related E. coli O157:H7 and one strain of E. coli K12 were individually grown on tryptic soy agar with 0.6% yeast extract (TSAYE). The cells were harvested and inoculated into sample matrices. Matrices included a moist buffered peptone water solution, a simple model low-moisture food matrix (corn syrup), and lowmoisture food (oat flour and peanut butter). Samples were individually heated using a Differential Scanning Calorimeter (DSC). The DSC was able to achieve a reproducible and accurate thermal environment. Following heat treatment, microbial survivors were enumerated via a traditional plate counting method. The six strains showed greater thermal resistance in corn syrup than in a buffered solution and in peanut butter and oat flour compared with both the corn syrup or buffer solution (p < 0.05). At the same processing condition linearly rising temperature at 5oC/min, in low moisture food matrices, approximately 90oC and 95oC was needed to reduce the outbreak strains of STEC in peanut butter and oat flour by 5-log CFU/g; whereas 85oC and 75oC were needed for corn syrup and buffer solution, respectively. D65 o C ranged from 0.26-0.92 min for all strains tested in buffer. Those same strains exhibited a 10-100 times increase in resistance in corn syrup (D65 o C = 2.6-108.6 min). The measurement that quantifies the increased heat resistance of STEC in low moisture food will improve science-based risk reduction by ensuring process lethality in these types of food.
M.S. in Food Safety and Technology, December 2014
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Title: ENRICHMENT OF COXIELLA BURNETII FROM BOVINE AND NON-BOVINE MILKS USING AN AXENIC LIQUID CULTURE MEDIUM
Creator: Shi, Manman
Date: 2016, 2016-07
Description: Non-bovine milks are becoming more popular as beverages and for making cheeses, however little are understood regarding how pathogens are...
Show moreNon-bovine milks are becoming more popular as beverages and for making cheeses, however little are understood regarding how pathogens are inactivated in these milks during pasteurization. Recently, a tissue culture-PCR method has been developed to quantify inactivation of Coxiella burnetii, the obligate intracellular bacterium which is the reference pathogen for milk pasteurization. Unfortunately, this method is time-consuming and quite laborious. A potential improvement over the ICC-PCR method may be the use of a new specialized liquid medium which has been shown to allow growth of pure cultures of C. burnetii outside of host cells. In this study, ACCM-2 was evaluated for its’ ability to enrich C. burnetii from bovine and non-bovine milks as a potential alternative to tissue culture enrichment for Most Probably Number (MPN) quantification of inactivation of C. burnetii in milks. C. burnetii in bovine whole milk and cream (as a surrogate for a high fat product), camel, water buffalo, and goat milk were grown in ACCM-2 media (1:10) in 10 mL volumes in T-25 flasks at 37 °C under 5% CO2 and 2.5% O2 with sampling over 14 days. C. burnetii levels were determined by quantitative PCR (qPCR) against a standard curve for the Coxiella-specific IS1111a gene. C. burnetii in all milks grew at least 3 logs over 10 days with the exception of the water buffalo milk which did not allow growth. Bovine milk allowed the least growth and additional studies determined that the detection limit for growth of C. burnetii from this milk is about 6 ge/mL. Additional studies showed that adjustment of the pH from ~5.0 to 4.75 results in much improved growth of C. burnetii from bovine milk. Adjustment of pH did not allow growth from water buffalo milk, however additional dilution of the milk did allow improved C. burnetii growth but the added dilution also decreases the detection limit of the proposed new MPN-PCR assay. Further studies were completed to determine how thermal injury affects recover and growth of Coxiella burnetii in ACCM-2 media after thermal processing at 64 °C for up to 8 minutes. Although injury did increase the lag phase period and reduce the log phase growth rate from these samples, recovery and growth of at least 0.5 log was possible from all samples indicating that this media should be useful as an alternative enrichment method for use in an MPN format for quantification of thermal inactivation of C. burnetii in both bovine and non-bovine milks.
M.S. in Food Safety and Technology, July 2016
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Title: WIRELESS LINK SCHEDULING UNDER PHYSICAL INTERFERENCE MODEL
Creator: Ma, Chao
Date: 2014, 2014-07
Description: Latency minimization and capacity maximization are fundamental combinatorial optimization problems in wireless networks. Given a set of...
Show moreLatency minimization and capacity maximization are fundamental combinatorial optimization problems in wireless networks. Given a set of communication links in a multihop wireless network, the former computes a schedule satisfying all link demands with shortest latency, while the latter aims at selecting a maximum feasible subset of these links. We study both the Shortest Link Schedule (SLS) and Maximum Independent Set of Links (MISL) from a theoretical perspective, striving for generalized algorithmic treatments and provable approximation guarantees. Wireless devices are prone to radio frequency interference emanating from other devices. Interference can be major inhibitor to transmission performance, degrading the signal quality or even causing the communication to fail. Several models have been used for modeling wireless interference over the past decades. In contrast to graph-based protocol models, which assume the interference end at some boundary, we consider a more realistic SINR-based physical interference model. Under physical interference model, the problem SLS and MISL are hard to solve due to the technical obstacles caused by the ambient noise, non-local and additive nature of interference. In this dissertation, we consider both fixed transmission powers and power control. We explore interference natures under physical interference model and propose a generalization of independent set, which is capable of modeling the independent sets of wireless links. In addition, we present constant-approximation algorithm for MISL with monotone and sub-linear power assignment in both unidirectional and bidirectional mode, and for MISL with sub-mean power assignment in bidirectional mode. We also present constant-approximation algorithm for Maximum Weighted Independent Set of Links (MWISL) with linear power assignment in both unidirectional and bidirectional mode. For MISL with power control in unidirectional mode, we develop a constant-approximation algorithm with the canonical iterative power assignment.
Ph.D. in Computer Science, July 2014
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Title: SYSTEMATIC CONSTRUCTION OF SALMONELLA ENTERITIDIS-SPECIFIC GENE DELETION MUTATIONS
Creator: Li, Ye
Date: 2013, 2013-12
Description: Salmonella enterica serovar Enteritidis infection is one of the major foodborne illnesses associated with egg, cattle and poultry products....
Show moreSalmonella enterica serovar Enteritidis infection is one of the major foodborne illnesses associated with egg, cattle and poultry products. Genes which are specific to S. Enteritidis may play an important functional role in the pathogens’ ability to survive and persist in these food products, and thus cause human foodborne outbreaks. Acquiring more knowledge on how this bacterium is capable of survival will aid in developing strategies to minimize its existence in the Nation’s food supply. In this study, we constructed S. Enteritidis-specific gene deletion mutants for use in subsequent functional studies. Out of more than 200 S. Enteritidis specific genes, 46 genes were selected for deletion in S. Enteritidis PT4. These 46 genes were selected because they are absent in both S. Typhimurium and S. Typhi based on percent identity scores retrieved from standalone BLAST software analysis. The deletion mutants were constructed using the lambda red recombinase method and a PCR product containing unique barcodes. This library of uniquely barcoded mutants will be useful in determining survival and persistence of this organism both in nature and in vivo.
M.S. in Food Safety and Technology, December 2013
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Title: HIGH PERFORMANCE LOGIC DESIGN FOR ADAPTIVE FIR FETAL ECG ESTIMATION
Creator: Wang, Sizhou
Date: 2014, 2014-05
Description: This thesis presents realizations of IEEE-754 single precision floating point non-invasive fetal ECG estimation based on QR Decomposition...
Show moreThis thesis presents realizations of IEEE-754 single precision floating point non-invasive fetal ECG estimation based on QR Decomposition Recursive Least Square algorithm (QRD-RLS). Experiments of the system, which is implemented on Xilinx Zynq SoC platform, are carried out with electrocardiogram (ECG) data and the results with analysis are presented. The embedded system design aims for saving resources, streaming pipeline performance and software-aid computation and integration. The challenge of exploiting the system full potential with pseudo-parallel computation on multiple fetal ECG data packets is also examined.
M.S. in Computer and Electrical Engineering, May 2014
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Title: MESOSCALE DEFORMATION IN A 9310 STEEL AND 2139 ALUMINUM ALLOY
Creator: Snyder, David
Date: 2012-09-10, 2012-12
Description: As technology continues to develop, the need for materials with superior structural performance grows. In recent years, the design of such...
Show moreAs technology continues to develop, the need for materials with superior structural performance grows. In recent years, the design of such high integrity alloys has led to a need for a more fundamental understanding of the deformation response of materials under various loading conditions. In this study, the deformation response of two high performance, high stacking fault metallic alloys are investigated. It has long been known that deformation in high stacking fault metals is a complex process of dislocation interactions that vary substantially with the loading conditions of strain, strain rate and temperature, as well as the chemistry and processing history of the alloy. The flow behavior and recrystallization response of a 9310 steel alloy deformed in the ferrite temperature range were studied in this work. Samples were compressed under various conditions of strain, strain rate and temperature using a Gleeble thermo-mechanical simulator. Deformation was characterized by both qualitative and quantitative means, using standard microscopy, electron backscatter diffraction (EBSD) analysis and flow stress modeling. The results indicate that deformation is primarily accommodated through dynamic recovery in sub-grain formation. EBSD analysis shows a continuous increase in sub-grain boundary misorientation with increasing strain, ultimately producing recrystallized grains from the sub-grains at high strains. This suggests that a sub-grain rotation recrystallization mechanism predominates in this temperature range. Demonstrated trends include a decreasing mean dynamically recrystallized grain size with increasing strain and Zener-Hollomon parameter, and an increasing recrystallized fraction with increasing strain. Another high stacking fault metal that has garnered a great deal of attention for its possible high performance structural applications is the 2139 aluminum alloy. In this study, the effect of chemistry and strain on the deformation response of the alloy system is investigated. 2139 aluminum is a very complex alloy, with multiple strengthening phases and mechanisms contributing to its overall high structural integrity compared to other aluminum alloys in its class. While the structural performance and TEM-scale deformation behavior of this alloy have been extensively analyzed, grain-scale microstructural features of deformation have not been well characterized. In addition, the contributions of each strengthening mechanism in the alloy are not well established. To characterize the deformation response of the alloy, alloys of various chemistries were produced and subjected to room temperature compression testing, in order to isolate and establish the effects of the major strengthening mechanisms on the overall behavior. Through electron backscatter diffraction analysis, the microstructural features of deformation generated in the alloys under these conditions were characterized, and the evolution and distribution of strain on a grain-scale was analyzed. Differences in deformation behavior with alloy chemistry were established by tracking differences in the evolution of lattice rotations with strain in the several alloys. It was determined that, for alloys subjected to artificial aging, the refinement in scale and distribution of the precipitate structure represents the greatest decrease in the development of lattice rotations with strain. This represents a first study into the room temperature, grain-scale deformation response of a heavily alloyed aluminum alloy, and the effect of alloy chemistry and precipitate structure on the deformation behavior of a 2139 aluminum alloy. As a preface to this study, a thorough review of the current state of literature on the deformation response of aluminum alloys was compiled as well.
M.S. in Materials Science and Engineering, December 2012
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Title: STUDIES IN NONEQUILIBRIUM STATISTICAL MECHANICS
Creator: Wang, Huichao
Date: 2013-05-08, 2013-05
Description: This thesis gives a brief outline of how the microscopic representation enters into a good description of the elasticity of a fluid. We first...
Show moreThis thesis gives a brief outline of how the microscopic representation enters into a good description of the elasticity of a fluid. We first introduce the hydrodynamics by three continuity equations. Due to its macroscopic background, we point out its limitation that it does not fit well with the elastic behavior of the fluid. Therefore we introduce the microscopic description of the system. In order to connect the elasticity which is obviously involved in the non-equilibrium state of a fluid, we discuss how non-equilibrium mechanics could be related to equilibrium mechanics by the assumption that the system is not far away from equilibrium. Under this assumption, an analysis of equilibrium mechanics is necessary, and combining with the microscopic representation, we derive the generalized Langevin equation as an equation of motion of the momentum current, which is endowed with the elastic property, consistent with observations of the fluid.
M.S. in in Physics, May 2013
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Title: SYSTEM-ON-CHIP ARCHITECTURES FOR SIGNAL PROCESSING AND COMMUNICAnONS
Creator: Niu, Sufeng
Date: 2012-04-30, 2012-05
Description: System-On-Chip (SOC) is one of the most popular Computer Aided Design (CAD) methodologies in electronic system design. In this research, SOC...
Show moreSystem-On-Chip (SOC) is one of the most popular Computer Aided Design (CAD) methodologies in electronic system design. In this research, SOC design is investigated in two different types of applications: i) low cost and power efficient applications; and ii) high performance computing applications. To explore low cost and power efficient design, a microcontroller based wireless medical system is investigated. Two wireless communication protocols for medical applications and patient monitoring are analyzed. In addition, the ZigBee stack developed by TI and a medical amplifier are discussed. For high performance SOC applications, implementations of several matrix operations are examined. An improved fixed-point hardware design of QR decomposition is introduced and optimized for Xilinx FPGAs. A Givens Rotation algorithm is implemented using a folded systolic array and the CORDIC algorithm. This approach is highly suitable for high-speed FPGAs or ASIC designs. It is found that the Xilinx XC5VLX110T FPGA is capable of running the QR decomposition at 246MHz.
M.S. in Electrical Engineering, May 2012
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Title: Improving Localization Safety for Landmark-Based LiDAR Localization System
Creator: Chen, Yihe
Date: 2024
Description: Autonomous ground robots have gained traction in various commercial applications, with established safety protocols covering subsystem...
Show moreAutonomous ground robots have gained traction in various commercial applications, with established safety protocols covering subsystem reliability, control algorithm stability, path planning, and localization. This thesis specifically delves into the localizer, a critical component responsible for determining the vehicle’s state (e.g., position and orientation), assessing compliance with localization safety requirements, and proposing methods for enhancing localization safety.Within the robotics domain, diverse localizers are utilized, such as scan-matching techniques like normal distribution transformations (NDT), the iterative closest point (ICP) algorithm,probabilistic maps method, and semantic map-based localization.Notably, NDT stands out as a widely adopted standalone laser localization method, prevalent in autonomous driving software such as Autoware and Apollo platforms.In addition to the mentioned localizers, common state estimators include variants of Kalman Filter, particle filter-based, and factor graph-based estimators. The evaluation of localization performance typically involves quantifying the estimated state variance for these state estimators.While various localizer options exist, this study focuses on those utilizing extended Kalman filters and factor graph methods. Unlike methods like NDT and ICP algorithms, extended Kalman filters and factor graph based approaches guarantee bounding of estimated state uncertainty and have been extensively researched for integrity monitoring.Common variance analysis, employed for sensor readings and state estimators, has limitations, primarily focusing on non-faulted scenarios under nominal conditions. This approach proves impractical for real-world scenarios and falls short for safety-critical applications like autonomous vehicles (AVs).To overcome these limitations, this thesis utilizes a dedicated safety metric: integrity risk. Integrity risk assesses the reliability of a robot’s sensory readings and localization algorithm performance under both faulted and non-faulted conditions. With a proven track record in aviation, integrity risk has recently been applied to robotics applications, particularly for evaluating the safety of lidar localization.Despite the significance of improving localization integrity risk through laser landmark manipulation, this remains an under explored territory. Existing research on robot integrity risk primarily focuses on the vehicles themselves. To comprehensively understand the integrity risk of a lidar-based localization system, as addressed in this thesis, an exploration of lidar measurement faults’ modes is essential, a topic covered in this thesis.The primary contributions of this thesis include: A realistic error estimation method for state estimators in autonomous vehicles navigating using pole-shape lidar landmark maps, along with a compensatory method; A method for quantifying the risk associated with unmapped associations in urban environments, enhancing the realism of values provided by the integrity risk estimator; a novel approach to improve the localization integrity of autonomous vehicles equipped with lidar feature extractors in urban environments through minimal environmental modifications, mitigating the impact of unmapped association faults. Simulation results and experimental results are presented and discussed to illustrate the impact of each method, providing further insights into their contributions to localization safety.
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Title: Using Niobium surface encapsulation and Rhenium to enhance the coherence of superconducting devices
Creator: Crisa, Francesco
Date: 2024
Description: In recent decades, the scientific community has grappled with escalating complexity, necessitating a more advanced tool capable of tackling...
Show moreIn recent decades, the scientific community has grappled with escalating complexity, necessitating a more advanced tool capable of tackling increasingly intricate simulations beyond the capabilities of classical computers. This tool, known as a quantum computer, features processors composed of individual units termed qubits. While various methods exist for constructing qubits, superconducting circuits have emerged as a leading approach, owing to their parallels with semiconductor technology.In recent years, significant strides have been made in optimizing the geometry and design of qubits. However, the current bottleneck in the performance of superconducting qubits lies in the presence of defects and impurities within the materials used. Niobium, owing to its desirable properties, such as high critical temperature and low kinetic inductance, stands out as the most prevalent superconducting material. Nonetheless, it is encumbered by a relatively thick oxide layer (approximately 5 nm) exhibiting three distinct oxidation states: NbO, NbO$_2$, and Nb$_2$O$_5$. The primary challenge with niobium lies in the multitude of defects localized within the highly disordered Nb$_2$O$_5$ layer and at the interfaces between the different oxides. In this study, I present an encapsulation strategy aimed at restraining surface oxide growth by depositing a thin layer (5 to 10 nm) of another material in vacuum atop the Nb thin film. This approach exploits the superconducting proximity effect, and it was successfully employed in the development of Josephson junction devices on Nb during the 1980s.In the past two years, tantalum and titanium nitride have emerged as promising alternative materials, with breakthrough qubit publications showcasing coherence times five to ten times superior to those achieved in Nb. The focus will be on the fabrication and RF testing of Nb-based qubits with Ta and Au capping layers. With Ta capping, we have achieved the best T1 (not average) decay time of nearly 600 us, which is more than a factor of 10 improvements over the bare Nb. This establishes the unique capping layer approach as a significant new direction for the development of superconducting qubits.Concurrently with the exploration of materials for encapsulation strategies, identifying materials conducive to enhancing the performance of superconducting qubits is imperative. Ideal candidates should exhibit a thin, low-loss surface oxide and establish a clean interface with the substrate, thereby minimizing defects and potential sources of losses. Rhenium, characterized by an extremely thin surface oxide (less than 1 nm) and nearly perfect crystal structure alignment with commonly used substrates such as sapphire, emerges as a promising material platform poised to elevate the performance of superconducting qubits.
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Title: Modeling and Optimization of Embedded Active Flow Control Systems
Creator: Henry, James M.
Date: 2024
Description: This thesis presents research focused on the aerodynamic performance of circulation control on two-dimensional and quasi-two-dimensional wings...
Show moreThis thesis presents research focused on the aerodynamic performance of circulation control on two-dimensional and quasi-two-dimensional wings. Aerodynamic loads, namely lift, drag, and moment coefficients, are measured through Reynolds Averaged Navier Stokes (RANS) modeling and wind tunnel experiment. A simplified and parameterized RANS model is presented as a rapidly iterable approach to estimating the performance of trailing-edge circulation control on two dimensional airfoils, with the hypothesis that an optimized airfoil shape can be found which maximizes the lift coefficient increment generated by circulation control, through modification of the wing profile. The simplified modeling setup is compared with more conventional approaches to numerical simulation of circulation control. The performance of the simplified modeling scheme is then compared with wind tunnel studies, for both steady-state and dynamic performance, as functions of both momentum coefficient dCμ and chord-based Reynolds number Re_c. The dynamic performance for the model is studied to find an analog to the theoretical unsteady models of Wagner and Theodorsen. An adjoint optimization framework is used to find an optimal airfoil profile for circulation control. The optimized profile is then compared in both a simulation and a wind tunnel test study against a NACA0015 airfoil. In simulation, improvement between 12% and 15% is seen for the lift control authority for all values of dCμ and Re_c tested. In experiment, the optimized profile demonstrated improvements of up to 28% in lift control authority, dCL/dCμfor values of Cμ, and decreased performance for higher values of Cμ.
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Title: EXPANDING THE HEP FRONTIER WITH BOOSTED B-TAGS AND THE QCD POWER SPECTRUM
Creator: Pedersen, Keith
Date: 2018, 2018-05
Description: As particle physics continues to expand into the high-energy and highluminosity frontiers, it is encountering event topologies with extreme...
Show moreAs particle physics continues to expand into the high-energy and highluminosity frontiers, it is encountering event topologies with extreme boosts and intense pileup. This creates unique challenges that limit our ability to use QCD jets to find new physics and conduct precision tests of the standard model. In this thesis, I present two tools that greatly expand our ability to use jets for these important purposes: (i) The μx boosted-bottom jet tag, whose O(100) signal to background ratio does not falter as jet pT exceeds 1TeV, and which is robust to pileup due to its foundation in boosted kinematics. (ii) Power jets, the first stage in a larger program to harness the power spectrum of QCD radiation to better utilize the vast amount of information collected about each collider event. Using the full power spectrum of a detected event, the power jets framework not only provides an accurate and precise recovery of jet kinematics, but also naturally facilitates a global fit to pileup intensity (rather than a local subtraction of pileup energy, which inadvertently strips soft QCD that belongs to the hard scatter).
Ph.D. in Physics, May 2018
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Title: INCORPORATION OF NATURAL SENSORY FEEDBACK TO BRAIN MACHINE INTERFACE WITH HAND EXOSKELETON
Creator: Qian, Kai
Date: 2018, 2018-05
Description: The feasibility of a brain-machine interface (BMI) system that links the brain to an external device has been demonstrated for both non-human...
Show moreThe feasibility of a brain-machine interface (BMI) system that links the brain to an external device has been demonstrated for both non-human and human subjects. However, BMI controlled robotic arm movements are usually slow, jerky and imprecise. Many of these problems can be attributed to a lack of somatosensory (tactile, proprioception, etc.) feedback. For a large segment of potential users who have motor impairments but intact sensation, use of an exoskeleton as the external device could provide the natural sensory feedback to improve BMI control. This is especially true for the hand with its incredibly rich sensory innervation. Currently, however, there is no hand exoskeleton available for non-human primate BMI research. In this dissertation, a hand exoskeleton platform was developed for an index finger - thumb precision grip task. The system was first employed as a scientific apparatus to explore the sensory responses in primary motor cortex (M1) to sinusoidal inputs of position and force. Neural firing rate patterns were found to be strongly entrained to the sinusoidal stimulus, with a predominance of neurons responding to joint movement rather than fingertip force. The phase-locking patterns to sinusoidal stimuli were much clearer and more stable for joint movement than for fingertip force as well. Second, the hand exoskeleton system was validated in a real-time BMI-controlled isometric grip force task. Prompted by cues on a computer screen, the monkey used cortical signals to control the grip force produced by the exoskeleton. The exoskeleton drove either the monkey’s own hand (natural sensory feedback condition) or an artificial hand (visual feedback only condition). Although improvements in performance for both conditions were observed over the relatively short training period, it was difficult to differentiate between the efficacy of the two conditions. Interestingly, for both conditions the monkey tried to use a similar neural strategy in controlling grip force as to the one used in natural grip behavior, in which a majority of the neurons recorded exhibited temporal reduction of the firing rates during the force production phase. Overall, the hand exoskeleton platform proved to be not only a powerful platform in BMI research but also an important tool for investigating sensory processing. This new platform should facilitate future experiments which will further insight into BMI design and the neural mechanisms underlying movement control.
Ph.D. in Biomedical Engineering, May 2018
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Title: HARDWARE ACCELERATION OF HASHING FUNCTIONS FOR CRYPTOCURRENCY MINING USING ZYNQ SOC
Creator: Rajagopal, Vignesh
Date: 2018, 2018-05
Description: Cryptocurrencies rely on secure hashing algorithms and public key cryptography to keep transactions secure, disallow double spending, and keep...
Show moreCryptocurrencies rely on secure hashing algorithms and public key cryptography to keep transactions secure, disallow double spending, and keep a decentralized ledger. In a bitcoin’s lifetime, the most computationally intensive work is done at conception. New bitcoins are brought into the ecosystem by a process named mining. While mining encompasses various mathematical functions and nuances that will be described in this thesis, the key element is a double SHA256 function, which has to be performed many times until the specified criterion is met. The focus in this thesis will be to speed up one iteration of this double hash function by making optimizations in hardware. The hashing function along with its optimizations will be implemented on Xilinx’s Zedboard, which contains both an FPGA chip as well as a microprocessor (ZYNQ7). Using Xilinx’s product suite, the double hashing function was taken from a high abstraction level language to low-level hardware deployment, following the design flow and applying various optimization methods, or directives. Some of the methods employed were array partitioning, pipelining, and loop unrolling. The primary goal in this thesis is not to simply achieve low latency; rather it is to reach a compromise between latency, power consumption, and area usage. Techniques are explored and tested both individually and in hybrid solutions and various practical tradeoffs are considered. Miners have to take into account the associated increase in hardware and power costs that come with high-area hardware implementations. After all, a miner is not going to want a setup that costs more to run than the worth of the Bitcoins mined. Therefore, the focus in this thesis is to optimize the double SHA256 hashing function for speed, area, and power. The work done has pointed towards array partitioning – a technique that brings frequently accessed variables from BRAM into registers. It allows for the best combination of decreased latency with only marginal increases in power and area. Utilized alongside pipelining, in tests, a speedup of 2.83x was achieved over an auto-optimized hardware implementation while decreasing both power consumption and the usage of look-up tables (LUTs) and flip-flops (FFs). Implementing these optimizations into a real-life mining rig, complete with comparator, incrementing nonce, and live block header construction has been left as future work. In addition, optimizing various other mathematical functions of the Bitcoin life cycle lies beyond the scope of this thesis. As such, this work serves to reduce latency for a single iteration of the double SHA256 function as it applies to Bitcoin mining, while taking into account practical considerations for the miner. The result is an IP core that can be instantiated 10-15 times in a modest FPGA chip and used in the development of a full mining rig.
M.S. in Electrical Engineering, May 2018
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Title: DESIGN FLOW OF ADVANCED ENCRYPTION STANDARD HARDWARE ACCELERATION USING ZYNQ SYSTEM-aN-CHIP
Creator: Rarick, Samuel
Date: 2018, 2018-05
Description: The Advanced Encryption Standard (AES) is a symmetric encryption algorithm used by the United States government to protect sensitive...
Show moreThe Advanced Encryption Standard (AES) is a symmetric encryption algorithm used by the United States government to protect sensitive information. In this study, three implementations of a 256-bit AES algorithm are presented to accelerate the computational elements of the algorithm: a low-area, high-performance, and hybrid implementation. The three implementations were developed for the ZedBoard development board which contains a Zynq-7000 SoC. The Zynq-7000 SoC contains both a processing system (dual-core ARM processor) and programmable logic (Xilinx-7 FPGA). This relation between hardware and software of the Zynq-7000 SoC was exploited by implementing the key schedule algorithm of AES on the dual-core ARM processor, while implementing the AES encryption core on the Xilinx-7 FPGA. A high-level synthesis design flow was followed for its flexibility and reduction of development time. The result for latency is about a 2.5 times acceleration for the low-area implementation, a 12 times acceleration for the hybrid implementation, and a 44 times acceleration for the high-performance implementation. For the area results, the high-performance implementation can theoretically fit 13 encryption cores on the ZedBoard, while both the low-area and hybrid implementations can theoretically fit 35 encryption cores on the ZedBoard.
M.S. in Computer Engineering, May 2018
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Title: CASE-ADAPTIVE PROCESSING FOR IMPROVING ACCURACY IN COMPUTER-AIDED DIAGNOSIS OF BREAST CANCER
Creator: Sainz De Cea, Maria Victoria
Date: 2018, 2018-05
Description: Breast cancer is the most commonly diagnosed cancer among women (apart from skin cancer) in the US. If detected early, the five-year survival...
Show moreBreast cancer is the most commonly diagnosed cancer among women (apart from skin cancer) in the US. If detected early, the five-year survival rate is 99%. Because of this, early detection of breast cancer has been an extensively studied topic over the years, and screening mammography is the gold standard for this purpose. Microcalcifications (MCs) are tiny calcium deposits that appear as bright spots in mammogram images, and they can be an early sign of breast cancer in asymptomatic women. Computer aided diagnosis (CAD) tools can be used to assist radiologists in detecting MCs and classifying them as benign or malignant. CAD of breast cancer is often hampered by the presence of false positives (FP) among the detected MCs when a reasonable sensitivity level is achieved. The FPs can be caused by MC-like noise, linear structures, etc. Due to the wide range of factors causing FPs, there is a great inter-patient variability, which can degrade the performance of CAD systems. In this work, we aim to reduce the inter-patient variability of CAD systems in order to improve the performance in both MC detection (Computer aided detection or CADe) and classification of MC clusters (Computer aided diagnosis or CADx). The first part of this thesis focuses on MC detection. We first develop a framework for estimating the accuracy in detection of individual MCs within a lesion region. This framework is general and can be applied to any MC detector. The number of FP detections can vary greatly from patient to patient, so having this knowledge will be useful to make decisions in both CADe and CADx systems. Secondly, we present a case-adaptive method for CADe based on Bayes’ risks, where a distribution is fit to the FPs from a mammogram under consideration, based on which the optimal detection threshold is determined for each patient. Finally we present an outlier approach for detection of individual MCs in a lesion region. This approach is based on the fact that individual MCs are usually different from the FPs (brighter, larger in extent), so they can be detected as statistical outliers. The outlier detection is done in a case-by-case basis, which can yield not only a reduction in the number of FPs but also an increase on the uniformity of the detection accuracy among different cases. The second part of the thesis is focused on CADx. We apply the methods developed in the first part to improve the uniformity and performance in the classification of detected lesions as benign or malignant. For this purpose we first present a quality factor approach for adjusting the contribution of the detected individual MCs to the final feature set. Those detections with a higher quality factor can have more impact in the final features, therefore mitigating the effect of the FP detections. Finally, we use the estimated detection accuracy to determine the optimal detection operating threshold. This is shown to boost the CADx performance.
Ph.D. in Electrical Engineering, May 2018
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Title: Medical Tourism Tower: board4
Creator: Liu, Sha, Zhao, Jie
Date: 2011, 2011-05
Description: This is the design of a medical tourism tower located in Seoul, Korea. It is a mixed-use high rise which includes three plastic surgery...
Show moreThis is the design of a medical tourism tower located in Seoul, Korea. It is a mixed-use high rise which includes three plastic surgery hospitals along with a luxury hotel.
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Title: CHARACTERIZING THE ROLE OF PCL1 IN YEAST PHEROMONE RECEPTOR POLARIZATION
Creator: Pai, Chih-yu
Date: 2015, 2015-05
Description: Chemotropism, or directed cell growth in response to a chemical gradient, plays a vital role in many processes, including pollen tube...
Show moreChemotropism, or directed cell growth in response to a chemical gradient, plays a vital role in many processes, including pollen tube formation, axon guidance, angiogenesis, and fungal infections. One of the best-studied models of eukaryotic directional sensing is Saccharomyces cerevisiae, also known as budding yeast. Chemotropic growth relies on both pheromone receptor and its associated G-protein. In vegetative yeast cells, the pheromone receptor is uniformly distributed on the plasma membrane. Upon receptor activation, G~y is released from Ga and G~ is subsequently phosphorylated at multiple residues. Free G~y signals to the nucleus via a MAPK cascade that causes G1 cell cycle arrest and induction of mating specific genes. In addition, G~y recruits various polarity proteins that orient actin-directed secretion to a specific growth site, and newly synthesized receptors are delivered to it. This pheromone-induced receptor polarization appears as "crescents" where the mating projection later forms. However, how yeast cell interpret the external signals and establish the chemotropic growth site remains unknown. Here, we characterized the role of Pcl1, which is a cyclin for the CDK Ph085, and which has been implicated in polarization during budding. It is known that G~ phosphorylation plays a role in receptor polarization and chemotropism. Because G~ has a consensus phosphorylation motif for Ph085, and because G~ and Pcl1 showed a genetic interaction, we hypothesized that Ph085-Pcl1 regulates receptor polarity through G~ phosphorylation. Our results showed Pcl1 localized towards mating projection during mating response. Moreover, Pcl1 and G~ exhibit a direct interaction in response to pheromone. Lastly Ph085 inactivation also appears to affect receptor polarity. Hence, our data are consistent with the hypothesis that Pho85-Pcl1 facilitates receptor polarity establishment by phosphorylating G~.
M.S. in Biology, May 2015
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