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外文学位

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  • [学位] Design and timing analysis of wave pipelined circuits
    In conventional pipelined circuits there is only one datawave active in any pipeline stage at any time; therefore, the clock speed of the circuit is limited by the maximum stage delay in the circuit. In wave pipelining, the clock speed depends mostly on the difference between the longest and shortest path delays. In some circuit designs there are redundant elements to make the circuit less sensitive to noise, to provide higher signal driving capability, or other purposes. Also, some circuit designs include logic to detect the early completion of a computation, or to guarantee that the worst physical path delay does not equate to the worst computational delay. Prior tools for wave-pipelined circuits do not account for such design features. This research develops a computer-aided design tool to determine the maximum clock speed for wave pipelined circuits with redundant logic or where otherwise the internal circuit timing depends on the input signal values. Moreover, alternative design techniques are proposed to improve the performance of wave pipelined circuits.
  • [学位] Applications of nanomanipulation coupled to nanospray mass spectrometry in trace fiber analysis and cellular lipid analysis
    The novel instrumentation of nanomanipulation coupled to nanospray mass spectrometry and its applications are presented. The nanomanipulator has the resolution of 10nm step sizes allowing for specific fine movement used to probe and characterize objects of interest. Nanospray mass spectrometry only needs a minimum sample volume of 300nl and a minimum sample size of 300attograms to analyze an analyte making it the ideal instrument to couple to nanomanipulation. The nanomanipulator is mounted to an inverted microscope and consists of 4 nano-positioners; these nano-positioners hold end-effectors and other tools used for manipulation. This original coupling has been used to enhance the current abilities of cellular probing and trace fiber analysis. Experiments have been performed to demonstrate the functionality of this instrument and its capabilities. Histidine and caffeine have been sampled directly from single fibers and analyzed. Lipid bodies from cotton seeds have been sampled indirectly and analyzed. The few applications demonstrated are only the beginning of nanomanipulation coupled to nanospray mass spectrometry and the possible applications are numerous especially with the ability to design and fabricate new end-effectors with unique abilities. Future study will be done to further the applications in direct cellular probing including toxicology studies and organelle analysis of single cells. Further studies will be directed in forensic applications of this instrument including gunshot residue sampled from fibers.
  • [学位] Technologies of apprehension: The family, law, security, and geopolitics in US noncitizen family detention policy and practice
    This dissertation examines how US immigrant family detention policy emerged from reinvigorated border security priorities, immigration policing practices, and international migration flows. Based on a qualitative mixed methods approach, the research traces how discourses of threat, vulnerability, and safety produce detainable child and parent subjects that displace “the family” as a legal entity. I show that immigration law relies on specific kinds of geographical knowledge, producing what I call the ‘geopolitics of vulnerability.’ More broadly, I analyze how current immigration enforcement practices work at local, national, and international scales, so that detention deters future migration as much as it penalizes existing undocumented migrants. Tracing how legal categorization, isolation, criminalization, and forced mobility discipline detained families, I show how detention bears down on migrant networks, defying individualized and national scalings of immigration law. Family detention, like the broader detention system, is authorized through overlapping forms of administrative discretion, and I analyze how the “plenary doctrine of immigration” resonates with ICE’s discretionary authority. Finally, I trace how immigrant rights advocates mobilizes conceptions of “home-like” and “prison-like” facilities, and how ICE reimagined its “residential” facilities in response. Empirically and theoretically, my project contributes the first academic study of US family detention to research on kinship, citizenship, security, geopolitics, and immigration enforcement. Keywords: Immigration, Detention, Feminism, Geopolitics, Borders.
  • [学位] A place-based assessment of food insecurity in the North Central Health District of Idaho
    The aim of this research is to understand the complexity of community food insecurity in a rural region of the United States. In this country food security is more about improper distribution than about scarcity. Quantifying why and where food distribution is not equitable or adequate depends on the context of place. Multiple indicators of food security specified in the literature were analyzed to create a food insecurity index. The index was compared to regional insight through the use of stakeholder surveys. We further analyzed the food insecurity index for spatial autocorrelation using Geographical Information Systems (GIS) technology to look for spatial patterns in the region of potential clustering or dispersal of the phenomena. Balancing top-down and bottom-up approaches, this project uses a mixed methods approach by testing the multidimensional indicators of food insecurity to uncover potential barriers that are affecting the most vulnerable areas within the region.
  • [学位] Discontinuous Galerkin methods for structural mechanics
    This thesis has two parts. In the first part, we uncover and study a new superconvergence phenomenon for a wide family of discontinuous Galerkin and hybridized methods for one-dimensional convection-diffusion problems. We show that, if the numerical traces are consistent and conservative, then they superconverge at the nodes of the triangulation. In particular, if polynomials of degree at most p are used for approximation then the convergence is of order 2p + 1 for the local discontinuous Galerkin methods and the hybridized Raviart-Thomas method. This implies that by using a simple and local post-processing, we can obtain approximations that converge uniformly with order 2p + 1 in the whole computational domain. Our numerical results are in agreement with our theoretical findings. In the second part, we introduce and analyze discontinuous Galerkin methods for the Timoshenko beams. We prove that a wide family of these methods are free from the so-called shear locking, that is, the performance of the method is not affected by the thickness of the beam. We prove optimal error estimates in the L2-norm and in the energy seminorm. As we did for convection-diffusion problems, we uncover and study new superconvergence properties for these methods. We show that the numerical traces superconverge with order 2p + 1 if all the unknowns are approximated with piecewise polynomials of degree at most p. We exploit this phenomenon to define computationally inexpensive post-processing techniques which produce approximate solutions converging with order 2p + 1 uniformly throughout the computational domain. Our numerical experiments verify our theoretical findings.
  • [学位] Spectrophotometric determination of irrigant extrusion using passive ultrasonic irrigation, endoactivator or conventional irrigation
    Introduction: Sodium hypochorite (NaOCl) is the irrigant most often used in endodontics due to its antimicrobial activity and tissue dissolution ability. Irrigation is critical to endodontic success and several new methods have been developed [Passive Ultrasonic Irrigation (PUI); EndoActivator (EA)] to improve irrigation efficacy. Using a novel spectrophotometric method, this study evaluated NaOCL irrigant extrusion during endodontic treatment. Methods: 114 single rooted extracted teeth were decoronated to leave 15 mm of root length for each tooth. Cleaning and shaping of teeth was completed using hand and rotary instrumentation (ProTaper[Dentsply]) to apical file size #40/0.04 taper. Root ends were sealed (not apex) and placed into a microcentrifuge tube with the coronal aspect sealed (Imprint [3M] and Revolution [Kerr]) to prevent inadvertent NaOCl leakage anywhere but from the canal. 54 straight roots (0° up to 20° curvature; n=18/group) and 60 curved roots (>20° curvature; n=20/group) were included. Teeth were irrigated with 5.25% NaOCl by one of three methods: conventional syringe irrigation; passive ultrasonic irrigation (PUI), or Endoactivator (EA) irrigation. Extrusion of NaOCl was evaluated using pH sensitive dye and a spectrophotometer (Synegy HT [BioTek]). Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples. Results: Irrigant extrusion was minimal with all methods, with most teeth showing no sodium hypochlorite extrusion (conventional 61.1%, PUI 72%, EA 78%) or minimal sodium hypochlorite extrusion (<1μl)conventional 16.7%, PUI 16.6%, EA 11%. Minor irrigant extrusion (1-3μl) occurred in 11% of teeth in all three irrigant methods of the straight root sample. One tooth in the PUI group extruded 41μl of irrigant due to an apical anomaly and was replaced to maintain n=18/group. Curved root sample showed minimal irrigant extrusion with all methods, with most teeth showing no sodium hypochlorite extrusion (conventional 65%, PUI 75%, EA 75%) or minimal sodium hypochlorite extrusion (<1μl) conventional 25%, PUI 15%, EA 5%. Minor irrigant extrusion (1-3μl) occurred in 10% of teeth in all groups of the curved root sample. Two teeth in the EA group extruded 3-10 μl of sodium hypochlorite. Conclusion: Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, yet apical anatomy can vary, allowing extrusion of irrigant. The spectrophotometric method used here is very sensitive and can detect <1μl of sodium hypochlorite extrusion, while providing quantification of irrigant levels extruded. Use of sodium hypochlorite has been cautioned in cases of an open apex, perforation and vertical root factures, but apical anatomy should also be evaluated.
  • [学位] Stable reference trajectory modification for handling actuator failure in control systems
    The issue of rapidly reconfiguring the reference trajectory under unanticipated actuator failures in order to regain lost performance or aircraft handling qualities is explored. The failures detected in real-time are compensated for by ensuring the input to the system reflects current system conditions. This thesis will also show that only the general structure of the failed system component is needed to achieve successful failure detection and reference trajectory reconfiguration. This approach allows the nominal control structure to remain unchanged in the presence of change flight and system conditions. Acceptable system performance is recovered by detecting the actuator failures in real-time. The benefit of this approach is that the modification does not alter the control gains of the closed loop system which eliminates the apprehensions associated with most adaptive control techniques. The implementation of this technique will be done on a linear ongitudinal model of an F-16 like aircraft and the efficacy of the basic approach will be shown through computer simulations.
  • [学位] Calculating LLR Topic Signatures with Dependency Relations for Automatic Text Summarization
    Topic Signatures based on Log Likelihood Ratio (LLR) values have been a staple of Automatic Text Summarization since originally proposed over a decade ago. In my thesis I propose an alternate method for counting information units and calculating the foreground and background probabilities for LLR calculations based on the participation of an information unit in dependency relations generated from a sentence rather than the sentence itself. I develop a generic text summarization system based on the Text Analysis Conference shared task guidelines and data in order to compare the proposed method of counting with the standard approach in the context of an applied task. Each counting method and unit of information definition is run as an experiment on TAC 2010 and TAC 2011 topic-based document collections and evaluated against human model summaries using ROUGE statistical measure of n-gram overlap. Although the results of the experiments are inconclusive, the topic signatures generated by the two approaches are different in the information units they contain. I conclude that an alternate evaluation framework and a semi-abstractive approach leveraging dependency relations themselves for summary generation are possible areas for future work and research.
  • [学位] Immunomodulatory effects of porcine interleukin-18 on a modified live vaccine immune response against swine influenza virus
    Current swine influenza vaccines fail to protect against the broad range of strains circulating within the United States. To induce effective broad cross-protection against influenza, strong humoral and cell-mediated immune responses are needed. However, animals are often vaccinated at a young age when they exhibit a host of dysregulated or insufficient immune responses including biased T cell polarization and immature inflammatory responses. Porcine neonates have diminished expression of IL-18 in their respiratory tract, a major site of infection in young animals. Initially named interferon-γ inducing factor (IGIF), IL-18 is most widely known for its potent ability to up-regulate expression of interferon-γ (IFN-γ), resulting in a phenotypic TH1 driven T cell polarization. For many infections, such as influenza, deficiencies in IL-18 expression have been shown to result in deleterious effects on the development of protective immune responses. Insufficient expression of IL-18 during neonatal development in swine may result in a reduced expansion of a TH1 immune response and may result in improper immunological polarization in response to vaccination. Based on findings by Kim et al. (2001), two amino acid conversions were introduced (E41A & K88A) to porcine IL-18 by PCR primer site directed mutagenesis. Synonymous mutations to human IL-18 (huIL-18) by Kim et al. (2001, 2002) resulted in 4-fold increases in biological activity and extended half-life. Replication-defective adenoviruses expressing either the wild type porcine IL-18 or the mutated form was generated. Additionally, to create a succinct swine influenza modified live virus (MLV) vaccine expression rIL-18 protein, the mutated form of IL-18 (mutIL-18) was inserted into the truncated region of the NS1Δ126 gene of an attenuated H3N2 modified live swine influenza virus. The properties of biological expression and biological activity of both wild type IL-18 and mutated IL-18 were assessed in vitro and in vivo. Replication-defective adenovirus expression vectors were confirmed to express high levels (>10ng/mL) of wild type and mutated forms of IL-18. The rIL-18 expressing constructs (MLV+mutIL-18, MLV+Ad5wtIL-18, and MLV+Ad5mutIL-18) were administered as single dose influenza vaccines. The immunomodulatory effects of wild type and mutated forms of IL-18 were evaluated for their efficacy to enhance the immune protection afforded by the MLV vaccine alone in response to heterosubtypic influenza challenge (H1N1). The MLV+Ad5mutIL-18 vaccination group resulted in significantly higher antibody titers post challenge compared to the MLV alone. Additionally, both groups receiving either mutIL-18 construct (MLV+mutIL-18, MLV+Ad5mutIL-18) exhibited significantly lower viral shedding post challenge, lower viral replication in the lungs, and reduced microscopic lung lesion scores at time of necropsy. Flow cytometric analysis of circulating lymphocyte populations revealed significant differences in cell populations between IL-18/non-IL-18 groups and adenovirus and non-adenovirus groups. CD4+CD8+ double positive (DP) and γ/δ T cells were the main cell populations activated upon influenza vaccination and heterosubtypic challenge. Results indicate that, along with rIL-18 administration, the type of expression vector (adenovirus or influenza) plays a significant role in determining cytokine expression and responding T cell populations.
  • [学位] Nuclear effects in neutrino interactions at low momentum transfer
    This is a study to identify predicted effects of the carbon nucleus environment on neutrino - nucleus interactions with low momentum transfer. A large sample of neutrino interaction data collected by the MINERvA experiment is analyzed to show the distribution of charged hadron energy in a region with low momentum transfer. These distributions reveal a major discrepancy between the data and a popular interaction model with only the simplest Fermi gas nuclear effects. Detailed analysis of systematic uncertainties due to energy scale and resolution can account for only a little of the discrepancy. Two additional nuclear model effects, a suppression/screening effect (RPA), and the addition of a meson exchange current process (MEC), are shown to improve the description of the data.

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