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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Equivalence testing for identity authentication using pulse waves from photoplethysmograph

Wu, Mengjiao January 1900 (has links)
Doctor of Philosophy / Department of Statistics / Suzanne Dubnicka / Christopher Vahl / Photoplethysmograph sensors use a light-based technology to sense the rate of blood flow as controlled by the heart’s pumping action. This allows for a graphical display of a patient’s pulse wave form and the description of its key features. A person’s pulse wave has been proposed as a tool in a wide variety of applications. For example, it could be used to diagnose the cause of coldness felt in the extremities or to measure stress levels while performing certain tasks. It could also be applied to quantify the risk of heart disease in the general population. In the present work, we explore its use for identity authentication. First, we visualize the pulse waves from individual patients using functional boxplots which assess the overall behavior and identify unusual observations. Functional boxplots are also shown to be helpful in preprocessing the data by shifting individual pulse waves to a proper starting point. We then employ functional analysis of variance (FANOVA) and permutation tests to demonstrate that the identities of a group of subjects could be differentiated and compared by their pulse wave forms. One of the primary tasks of the project is to confirm the identity of a person, i.e., we must decide if a given person is whom they claim to be. We used an equivalence test to determine whether the pulse wave of the person under verification and the actual person were close enough to be considered equivalent. A nonparametric bootstrap functional equivalence test was applied to evaluate equivalence by constructing point-wise confidence intervals for the metric of identity assurance. We also proposed new testing procedures, including the way of building the equivalence hypothesis and test statistics, determination of evaluation range and equivalence bands, to authenticate the identity.
2

An Empirical Approach to Evaluating Sufficient Similarity: Utilization of Euclidean Distance As A Similarity Measure

Marshall, Scott 27 May 2010 (has links)
Individuals are exposed to chemical mixtures while carrying out everyday tasks, with unknown risk associated with exposure. Given the number of resulting mixtures it is not economically feasible to identify or characterize all possible mixtures. When complete dose-response data are not available on a (candidate) mixture of concern, EPA guidelines define a similar mixture based on chemical composition, component proportions and expert biological judgment (EPA, 1986, 2000). Current work in this literature is by Feder et al. (2009), evaluating sufficient similarity in exposure to disinfection by-products of water purification using multivariate statistical techniques and traditional hypothesis testing. The work of Stork et al. (2008) introduced the idea of sufficient similarity in dose-response (making a connection between exposure and effect). They developed methods to evaluate sufficient similarity of a fully characterized reference mixture, with dose-response data available, and a candidate mixture with only mixing proportions available. A limitation of the approach is that the two mixtures must contain the same components. It is of interest to determine whether a fully characterized reference mixture (representative of the random process) is sufficiently similar in dose-response to a candidate mixture resulting from a random process. Four similarity measures based on Euclidean distance are developed to aid in the evaluation of sufficient similarity in dose-response, allowing for mixtures to be subsets of each other. If a reference and candidate mixture are concluded to be sufficiently similar in dose-response, inference about the candidate mixture can be based on the reference mixture. An example is presented demonstrating that the benchmark dose (BMD) of the reference mixture can be used as a surrogate measure of BMD for the candidate mixture when the two mixtures are determined to be sufficiently similar in dose-response. Guidelines are developed that enable the researcher to evaluate the performance of the proposed similarity measures.
3

An Analysis of the Influence of Sampling Methods on Estimation of Drug Use Prevalence and Patterns Among Arrestees in the United States: Implications for Research and Policy

Kremling, Janine 31 May 2010 (has links)
Using data from the Drug Use Forecasting (DUF) and the Arrestee Drug Abuse Monitoring (ADAM) programs collected by the National Institute of Justice the question whether the drug estimates of DUF, using a non-probability sample, and the drug use estimates of ADAM, using a probability sample, yield substantially different results will be explored. The following main questions will be addressed using equivalence analysis: Are there substantial differences in the DUF and ADAM samples with regard to the drug use information obtained from arrestees at nine sites across the United States? The analysis suggests that the drug use information contained in DUF and ADAM is not substantially different for marijuana, cocaine, and opiates for all sites analyzed together. Additionally, there are no substantial differences for seven of the nine sites. The implications of these findings are discussed.
4

The ecology of translocated greater sage-grouse in Strawberry Valley, Utah

Baxter, Rick Joseph 20 November 2007 (has links) (PDF)
Manuscript No. 1 Translocations of greater sage-grouse (Centrocercus urophasianus) have been attempted in 7 states and one Canadian province with very little success. To recover a small remnant population and test the efficacy of sage-grouse translocations, we captured and transported 137 adult female sage-grouse from 2 source populations to a release site in Strawberry Valley, Utah during March-April 2003-2005. The resident population of sage-grouse in Strawberry Valley was approximately 150 breeding birds prior to the release. We radiomarked each female and documented survival, movements, reproductive effort, flocking with resident grouse, and lek attendance. We used Program MARK to calculate annual survival of translocated females in the first year after release, which averaged 0.60 (95% CI = 0.515-0.681). Movements of translocated females were within current and historic sage-grouse habitat in Strawberry Valley, and we detected no grouse outside of the study area. Nesting propensity for first (newly translocated) and second (surviving) year females was 39% and 73%, respectively. Observed nest success of all translocated females during the study was 67%. By the end of their first year in Strawberry Valley, 100% of the living translocated sage-grouse were in flocks with resident sage-grouse. The translocated grouse attended the same lek as the birds with which they were grouped. In 2006, the peak male count for the only remaining active lek in Strawberry Valley was almost 4 times (135 M) the 6-year pretranslocation (1998 − 2003) average peak attendance of 36 males (range 24 – 50 M). Translocations can be an effective management tool to increase small populations of greater sage-grouse when conducted during the breeding season and before target populations have been extirpated. Manuscript No. 2 Nesting habitat of resident greater sage-grouse in extant populations across the species range has been thoroughly described in the literature, yet very little is known about the use of nesting habitat by translocated sage-grouse. In order to better understand nesting habitat selection by translocated sage-grouse in a new environment, we trapped grouse during the spring on and near leks of source populations. We placed each female in a cardboard box and translocated them overnight to the Strawberry Valley. Each female was fitted with a radio-transmitter and released near the lek where males were actively strutting. We monitored grouse for nesting activity. We documented nesting attempts, nest success, clutch size and embryo viability. We recorded data on habitat variables associated with nest sites and paired-random sites. We used logistic regression and an a priori information theoretic approach for modeling nest versus paired-random sites and successful versus unsuccessful nest sites. Our data suggested that crown area of the nest shrub and percent grass cover were the two variables that discriminated between nest and paired-random sites. Females that nested successfully selected sites with more total shrub canopy cover, intermediate size shrub crown area, a normal distribution of aspects, and with steeper slopes than unsuccessful nests. Translocated females selected suitable nesting habitat after being moved from source populations with differing habitats. Manuscript No. 3 Equivalence testing in the field of wildlife ecology has been underutilized. Mistakenly, many researchers have concluded that two groups are the same based on failure to reject a null hypothesis of no difference. We used equivalence testing to provide preliminary evidence that resident and translocated bird movements were similar. Translocations are becoming more prominent in the field of conservation biology as a wildlife management tool. We translocated greater sage grouse into a fragmented habitat in order to conserve the metapopulation. We placed radio-transmitters on resident and translocated female greater sage grouse and used the distance moved from the release site or lek as a measure of translocation success and/or site fidelity. If translocated birds did not show site fidelity, the translocations would be judged a failure. The distributions of resident and translocated sage grouse movements for both summer and winter seasons were significantly different, primarily due to differences in the proportions of specific habitat fragments used. Equivalence tests showed that site fidelity was statistically equivalent for translocated and resident grouse,when defined as a difference of ≤3 km, both in summer and winter. In particular, translocated females traveled no farther from the release site than resident females. Equivalence testing was the statistical tool used to determine equivalence of resident and translocated sage grouse movements and thus judge preliminary translocation success.

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