Gaussian process convolutions for Bayesian spatial classification

Master's Project (M.S.) University of Alaska Fairbanks, 2016We compare three models for their ability to perform binary spatial classification. A geospatial data set consisting of observations that are either permafrost or not is used for this comparison. All three use an underlying Gaussian process. The first model considers this process to represent the log-odds of a positive classification (i.e. as permafrost). The second model uses a cutoff. Any locations where the process is positive are classified positively, while those that are negative are classified negatively. A probability of misclassification then gives the likelihood. The third model depends on two separate processes. The first represents a positive classification, while the second a negative classification. Of these two, the process with greater value at a location provides the classification. A probability of misclassification is also used to formulate the likelihood for this model. In all three cases, realizations of the underlying Gaussian processes were generated using a process convolution. A grid of knots (whose values were sampled using Markov Chain Monte Carlo) were convolved using an anisotropic Gaussian kernel. All three models provided adequate classifications, but the single and two-process models showed much tighter bounds on the border between the two states

Crustal evolution of the northern Arabian Platform beneath the Syrian Arab Republic

Copyright 1991, John Best. See also: http://atlas.geo.cornell.edu/dissertations/Best_1991.htmNewly released geological and geophysical data from the Syrian Arab Republic are used to document the geological history of the northern Arabian platform in the Middle East. The primary observation of this synthesis is the focusing of various phases of Phanerozoic deformation (Mesozoic rifting and Cenozoic transpression) along strike of a proposed Proterozoic suture that has acted as a long-lived zone of crustal weakness. This deformation zone is presently manifested by the intracontinental Palmyride mountain belt, an inverted rift, trending NE-SW through central Syria. The geological history recognized for the northern Arabian platform is similar in many respects to that of the southern Arabian platform, including: (1) Proterozoic convergence and cratonization, (2) minor Cambrian extension, (3) a relatively stable Paleozoic margin of Gondwanaland marked by predominantly clastic deposition, (4) eastward tilting of the Arabian plate in the Cenozoic. The important difference in the evolution of the northern platform from the southern platform occurs during the Mesozoic with the development of the Levantine margin in the eastern Mediterranean and the Palmyride rift in the continental interior. The intracontinental Palmyride mountain belt is the result of Late Cretaceous-present inversion of the Palmyride rift. Reactivation of rift boundary faults occurred in response to transpressive movement along basement-controlled strike-slip faults. The belt is divided into three provinces based on changes in structural style: the south Palmyride fold belt characterized by narrow, en enchelon ridges, the Bishri, and Bilas blocks expressed as broad, antiformal structures. The mountain belt may be characterized by thin-skinned deformation in the south fold belt and thick-skinned deformation in the northern and eastern provinces

Phylogeny as a proxy for ecology in seagrass amphipods: which traits are most conserved?

Increasingly, studies of community assembly and ecosystem function combine trait data and phylogenetic relationships to gain novel insight into the ecological and evolutionary constraints on community dynamics. However, the key to interpreting these two types of information is an understanding of the extent to which traits are phylogenetically conserved. In this study, we develop the necessary framework for community phylogenetics approaches in a system of marine crustacean herbivores that play an important role in the ecosystem functioning of seagrass systems worldwide. For 16 species of amphipods and isopods, we (1) reconstructed phylogenetic relationships using COI, 16S, and 18S sequences and Bayesian analyses, (2) measured traits that are potentially important for assembling species between and within habitats, and (3) compared the degree to which each of these traits are evolutionarily conserved. Despite poor phylogenetic resolution for the order Amphipoda as a whole, we resolved almost all of the topology for the species in our system, and used a sampling of ultrametric trees from the posterior distribution to account for remaining uncertainty in topology and branch lengths. We found that traits varied widely in their degree of phylogenetic signal. Body mass, fecundity, and tube building showed very strong phylogenetic signal, and temperature tolerance and feeding traits showed much less. As such, the degree of signal was not predictable based on whether the trait is related to environmental filtering or to resource partitioning. Further, we found that even with strong phylogenetic signal in body size, (which may have large impacts on ecosystem function), the predictive relationship between phylogenetic diversity and ecosystem function is not straightforward. We show that patterns of phylogenetic diversity in communities of seagrass mesograzers could lead to a variety of interpretations and predictions, and that detailed study of trait similarities and differences will be necessary to interpret these patterns

Costs and Benefits of Full Dual-Frame Telephone Survey Designs

Assesses the cost, sample composition, weighting, and substantive effect on survey results involved in interviewing respondents by cell phone, including those with landlines. Includes demographic profiles of cell phone-only, landline-only, and dual users

Loss-of-Mains Protection System by Application of Phasor Measurement Unit Technology with Experimentally Assessed Threshold Settings

Loss-of-mains protection is an important component of the protection systems of embedded generation. The role of loss-of-mains is to disconnect the embedded generator from the utility grid in the event that connection to utility dispatched generation is lost. This is necessary for a number of reasons, including the safety of personnel during fault restoration and the protection of plant against out-of-synchronism reclosure to the mains supply. The incumbent methods of loss-of-mains protection were designed when the installed capacity of embedded generation was low, and known problems with nuisance tripping of the devices were considered acceptable because of the insignificant consequence to system operation. With the dramatic increase in the installed capacity of embedded generation over the last decade, the limitations of current islanding detection methods are no longer acceptable. This study describes a new method of loss-of-mains protection based on phasor measurement unit (PMU) technology, specifically using a low cost PMU device of the authors' design which has been developed for distribution network applications. The proposed method addresses the limitations of the incumbent methods, providing a solution that is free of nuisance tripping and has a zero non-detection zone. This system has been tested experimentally and is shown to be practical, feasible and effective. Threshold settings for the new method are recommended based on data acquired from both the Great Britain and Ireland power systems

Statistical distribution models : goodness of fit tests

The purpose of a one-sample test of fit is to give an objective measure of how well a probability model agrees with observed data. Here we discuss the test of Karl Pearson and derivatives of it, tests based on the empirical distribution function and the construction of the Neyman-Barton smooth tests. In the final section, we then address some modern developments in smooth testing: diagnostics, Cholesky components, data-driven tests and model selection. Other tests of fit, such as correlation tests and Laplace transform tests, are not considered here

Global Music Perspectives: Music Outside the Western Canon in Local Schools

As a class, we are designing a research project for investigating how music teachers from counties in South-Central Pennsylvania use music from outside the Western canon (i.e. world music ). We are performing a qualitative study by interviewing k-12 music teachers from school districts in South-Central Pennsylvania. Teachers may choose to participate in a focus group interview with other teachers or in one-on-one interviews. The focus group interview will not exceed two hours and the one-on-one interviews will not exceed an hour. The interviews will be guided using a questionnaire (see attached), but the conversation may deviate from these questions at the discretion of the interviewer(s). We will transcribe these interviews to extract common thematic materials and relevant information. We will also compile a literature review of relevant peer-reviewed articles and use the data from said articles to expand upon our gathered information