Novel Asymmetrical Pulse Width Modulation Method

The paper proposes new asymmetrical PWM that can be used for operation of multilevel inverters. The working and construction principle of this PWM is demonstrated on 13-level PWM signal that is applied to nine-level inverter and operates it as 13-level inverter. The proposed PWM signal consists of 5-level hybrid PWM which is constructed from two PWM signals- combined parts of the standard 5-level Phase Disposition (PD) PWM and pulsed PWM. The sum of these two PWM signals produces the desired 13-level PWM signal that is applied to the 9-level cascaded inverter. The proposed PWM method allows reduction of 13-level inverter components compared to the standard topologies such as neutral point clamped or flying capacitor inverters. This results in smaller size, weight and cists of the inverter.. Extensive simulation results validate the practicability of the proposed PWM method. The proposed method can be extended to any desired number of levels

Non-Linear Interactions between Consumers and Flow Determine the Probability of Plant Community Dominance on Maine Rocky Shores

Although consumers can strongly influence community recovery from disturbance, few studies have explored the effects of consumer identity and density and how they may vary across abiotic gradients. On rocky shores in Maine, recent experiments suggest that recovery of plant- or animal- dominated community states is governed by rates of water movement and consumer pressure. To further elucidate the mechanisms of consumer control, we examined the species-specific and density-dependent effects of rocky shore consumers (crabs and snails) on community recovery under both high (mussel dominated) and low flow (plant dominated) conditions. By partitioning the direct impacts of predators (crabs) and grazers (snails) on community recovery across a flow gradient, we found that grazers, but not predators, are likely the primary agent of consumer control and that their impact is highly non-linear. Manipulating snail densities revealed that herbivorous and bull-dozing snails (Littorina littorea) alone can control recovery of high and low flow communities. After ∼1.5 years of recovery, snail density explained a significant amount of the variation in macroalgal coverage at low flow sites and also mussel recovery at high flow sites. These density-dependent grazer effects were were both non-linear and flow-dependent, with low abundance thresholds needed to suppress plant community recovery, and much higher levels needed to control mussel bed development. Our study suggests that consumer density and identity are key in regulating both plant and animal community recovery and that physical conditions can determine the functional forms of these consumer effects

A dc-link voltage stability analysis technique for hybrid five-phase open-end winding drives

This paper studies the dc-link voltage stability for a hybrid five-phase open-end winding (OeW) drive operating under carrier based (CB) pulse-width modulation (PWM). The drive consists of a five-phase induction machine, supplied using one three-level and one two-level voltage source inverter (VSI). This configuration is analysed for the case of isolated dc-link rails, while dc-link voltage ratio is considered as an additional degree of freedom. It is demonstrated that different dc-link voltage ratios lead to the different overall number of voltage levels across stator windings. Modulation strategies are investigated and their performances are analysed from the dc-link voltages stability point of view. An analytical method for dc-link voltage stability analysis is presented. Results show that the four-level configuration always leads to stable dc-link voltages, regardless of the modulation strategy. On the other hand, if six-level configuration is combined with modulation strategies that lead to an optimal harmonic performance, not all dc-link capacitor voltages will be in balance depending on the operating conditions

Time Series Analysis of National League Slugging Percentage (Major League Baseball)

Time Series Analysis of National League Slugging Percentage (Major League Baseball) Major League Baseball records yearly National League slugging percentage values, and for this project the data was examined using a time series with 103 data points, from 1901-2003. The analyses performed include exploratory data analysis such as the plot of the time series, a histogram, a normal QQ-plot, and the Autocorrelation Function and Partial Autocorrelation function of the series. Numerous general choices for which model to select for the data such as Autoregressive (AR) and Moving Average (MA) models were considered, as well as possible transformations or differencing of the data in order to obtain stationarity and constant variance of the series. Once these possible models were chosen, the next step was fitting the models to the series and analyzing the coefficients through parameter estimation, as well as performing a diagnostic check of the residuals for each model. Information Criterion values were also used to interpret the results of the model fitting. To confirm any hypotheses made to that point, predictions were done to evaluate the success of the model in terms of forecasting future values. In this case, the time series including the years from 1901-2003 was used to predict the slugging percentage values for the next ten years, from 2004-2013. Clearly, these results have already been obtained, so the effectiveness of the forecasting was determined decisively by comparing the predicted values and actual values for each model being tested. A convincing choice of the optimal model for this time series was attained. Discipline: Statistics Faculty Mentor: Dr. Cristina Anto

Thomas's Function and its properties at irrational and rational numbers

Thomas's function is a very unique phenomenon in mathematics, as its characteristics are very unusual. Its continuity at irrational numbers and discontinuity at rational numbers will be proven. This is done using standard real analysis definitions along with some creativity at the same time. Discipline: Mathematics Faculty Mentor: Dr. Nataliya Zadorozhn

Limiting Autoimmune Neuroinflammation using Novel T Cell Suppressants & Investigating Overlapping Lysosomal Reductase Function in Macrophages and Osteoclasts

Aberrant activation of adaptive immune cells can culminate in autoimmune diseases such as multiple sclerosis (MS). Recently, potent anti-inflammatory properties for the cooling compound, icilin, and its receptor target, Transient Receptor Potential Melastatin-8 (TRPM8), were characterized in the context of inflammatory colitis—the first half of this dissertation describes an attempt to repurpose the anti-inflammatory qualities of icilin and TRPM8 for the treatment of lymphocyte-mediated neuroinflammation. We found icilin treatment strongly attenuated experimental autoimmune encephalomyelitis (EAE), a murine model of MS, via an unexpected TRPM8-independent mechanism. Icilin inhibited the proliferation, polarization and downstream effector function of CD4+ T cells, suggesting a promising drug for limiting neuroinflammation. Citing the advantageous pharmacodynamics of icilin, we additionally screened a library of icilin-related analogues for anti-proliferative character. We identified several lead compounds with improved anti-proliferative properties compared to icilin in vitro and preliminary efficacy in vivo limiting EAE severity. Collectively, this work characterizes a new class of T cell suppressants while emphasizing clear off-target effects for the cooling drug icilin beyond TRP channel activation. Antigen presenting cells such as macrophages process phagocytosed cargo within the highly degradative phagolysosome, facilitating antigenic stimulation of T cells and adaptive immunity. The redox microenvironment of the phagolysosomal lumen regulates several phagolysosomal biochemistries, including proteolysis and disulfide reduction. The lysosomal enzyme γ-interferon-inducible lysosomal thiol reductase (GILT) directly catalyzes disulfide reduction and enhances proteolysis by thiol-dependent cysteine cathepsins within the phagolysosome—while clearly implicated in antigen processing, secondary roles for GILT remain largely undefined. The second half of this dissertation establishes a role for GILT in osteoclasts, bone resorbing cells derived from macrophages. GILT expression was highly upregulated in osteoclasts in response to osteoclastogenic and inflammatory cytokines, and GILT-deficient mice were discovered to be osteopetrotic. In vitro, GILT-deficient osteoclasts demonstrated a reduced capacity to resorb bone. GILT not only directly reduced disulfides within bone matrix structural proteins, but also enhanced the activity of cathepsin K, the prototypical osteoclast collagenase. Thus, this work reveals a novel, non-immunological role for GILT in osteoclast function and bone turnover