Novel Convergence Results in Nonlinear Filtering

In this dissertation, the discrete-time extended Kalman filter is analyzed for its ability to attenuate finite-energy disturbances, known as the H-infinity property. Though the extended Kalman filter is designed to be a locally optimal minimum variance estimator, this dissertation proves that it has additional properties, such as H-infinity. This analysis is performed with the extended Kalman filter in direct form. Since this form reduces assumptions placed on the system in previous works on convergence and H-2 properties of the extended Kalman filter, the extended Kalman filter used as a nonlinear observer for noise-free models is revisited using the direct form to demonstrate these properties. Additionally, two representations for the discrete-time uncertain measurement model with finite-energy disturbances are considered: 1) each sensor in the measurement can fail independently with different failure rates and 2) all of the sensors in the measurement fail at the same time. The discrete-time extended Kalman filters designed for such models are analyzed for general convergence, the H-2 property, and the H-infinity property. As an extension of this work, the continuous-time extended Kalman filter is applied to systems with finite-energy disturbances. This continuous-time extended Kalman filter is shown to inherently have the H-infinity property. Simulation studies have been performed on all of the extended Kalman filters in this dissertation. These simulation studies demonstrate that when the extended Kalman filters converge, they will also exhibit the H-2 and H-infinity properties. The bounds developed on these properties are affected by the same constraints that affect convergence, i.e. magnitudes of the initial estimation error and the disturbance as well as the severity of the nonlinearities in the model

Founders\u27 Day 1960

Founders\u27 Day 1960 with speakers President Harvey Rice, Professor O.T. Walter, as well as Edmund Wood, Kay Lorans, Fred Koch, and George Bonniwell. Reel #3

Deterministic and Stochastic Resilience Analysis of Minimum-time-controlled Discrete-time Systems

The resilience of discrete-time systems subject to minimum-time control is analysed for both deterministic and stochastic control gain perturbations. Lyapunov analysis is used to determine a tight upper bound on the control gain perturbations to maintain asymptotic stability

Settlement Of Crassostrea Ariakensis Larvae: Effects Of Substrate, Biofilms, Sediment And Adult Chemical Cues

The Suminoe oyster (Crassostrea ariakensis) is being considered for introduction into the Chesapeake Bay. However, our current understanding of the biology and ecology of C. ariakensis is insufficient to predict whether an introduction will be successful, provide desired benefits, or have adverse impacts. Behavior of native Eastern oyster (C. virginica) pediveligers has been studied for many years and it is well established that they use a variety of habitat characteristics when selecting a site for colonization. Perhaps the most important of these are chemical cues emitted by adult conspecifics, which can lead to gregarious larval settlement and dense, persistent reef communities. Conversely, almost nothing is known about the mechanisms that regulate larval settlement and metamorphosis for C. ariakensis or how pediveligers might respond to conditions found in Chesapeake Bay. In a comparative study with C. virginica, we examined how environmental factors such as substrate type, natural biofilms, sediment and waterborne chemical cues influence larval settlement for two C. ariakensis strains (‘‘south China’’ and ‘‘west coast’’). Our results demonstrate many similarities but also potentially important differences. Both species and strains of larvae greatly prefer natural substrates (e.g., shell) covered with biofilms for colonization but the west coast strain of C. ariakensis exhibited greater attachment onto manmade substrates (e.g., fiberglass) than C. virginica. Waterborne chemical cues emitted by adult oysters were also found to enhance substrate attachment for all larval forms but cues do not appear to be species specific. These results provide critical insight to the ability of C. ariakensis larvae to identify and colonize suitable substrates in the Chesapeake Bay, which will have a large impact on recruitment success and their ability to establish self-sustaining populations

Investigation of relationship between vitamin D status and reproductive fitness in Scottish hill sheep

There is a growing interest in the influence of vitamin D on ovine non-skeletal health. The aim of this study was to explore the relationship between pre-mating vitamin D status, as assessed by serum concentrations of 25-Hydroxyvitamin D [25(OH)D; comprising D2 and D3] and subsequent reproductive performance of genetically unimproved Scottish Blackface (UBF), genetically improved Scottish Blackface (IBF) and Lleyn ewes kept under Scottish hill conditions. 25-Hydroxyvitamin D2 (25(OH)D2) and 25-Hydroxyvitamin D3 (25(OH)D3) concentrations were determined in serum samples harvested in November from ewes grazed outdoors. There were no significant differences in 25(OH)D2concentrations amongst the 3 genotypes. Lleyn ewes had significantly higher 25(OH)D3 and 25(OH)D concentrations than both Scottish Blackface ewe genotypes, whereas these vitamin D parameters did not differ significantly between the UBF and IBF ewes. Concentrations of 25(OH)D3 and 25(OH)D were positively associated with subsequent birth weights of singleton and of twin lamb litters. No significant associations between vitamin D status and number of lambs born or weaned per ewe were found. This study demonstrates that concentrations of cutaneously-derived 25(OH)D3, but not of orally consumed 25(OH)D2, differed between breeds. The positive association between ewe vitamin D status and offspring birth weight highlights the need for further investigations

Sediment source fingerprinting: benchmarking recent outputs, remaining challenges and emerging themes

Abstract: Purpose: This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international scientists either with track records in the approach or with expertise relevant to progressing the science. Methods: Web of Science and Google Scholar were used to review published papers spanning the period 2013–2019, inclusive, to confirm publication trends in quantities of papers by study area country and the types of tracers used. The most recent (2018–2019, inclusive) papers were also benchmarked using a methodological decision-tree published in 2017. Scope: Areas requiring further research and international consensus on methodological detail are reviewed, and these comprise spatial variability in tracers and corresponding sampling implications for end-members, temporal variability in tracers and sampling implications for end-members and target sediment, tracer conservation and knowledge-based pre-selection, the physico-chemical basis for source discrimination and dissemination of fingerprinting results to stakeholders. Emerging themes are also discussed: novel tracers, concentration-dependence for biomarkers, combining sediment fingerprinting and age-dating, applications to sediment-bound pollutants, incorporation of supportive spatial information to augment discrimination and modelling, aeolian sediment source fingerprinting, integration with process-based models and development of open-access software tools for data processing. Conclusions: The popularity of sediment source fingerprinting continues on an upward trend globally, but with this growth comes issues surrounding lack of standardisation and procedural diversity. Nonetheless, the last 2 years have also evidenced growing uptake of critical requirements for robust applications and this review is intended to signpost investigators, both old and new, towards these benchmarks and remaining research challenges for, and emerging options for different applications of, the fingerprinting approach

The challenges and opportunities of addressing particle size effects in sediment source fingerprinting: A review

publisher: Elsevier articletitle: The challenges and opportunities of addressing particle size effects in sediment source fingerprinting: A review journaltitle: Earth-Science Reviews articlelink: http://dx.doi.org/10.1016/j.earscirev.2017.04.009 content_type: article copyright: © 2017 Elsevier B.V. All rights reserved