399 research outputs found
Bayesian Functional Data Analysis Using WinBUGS
We provide user friendly software for Bayesian analysis of functional data models using \pkg{WinBUGS}~1.4. The excellent properties of Bayesian analysis in this context are due to: (1) dimensionality reduction, which leads to low dimensional projection bases; (2) mixed model representation of functional models, which provides a modular approach to model extension; and (3) orthogonality of the principal component bases, which contributes to excellent chain convergence and mixing properties. Our paper provides one more, essential, reason for using Bayesian analysis for functional models: the existence of software.
Analysis and optimization methods of graph based meta-models for data flow simulation
Data flow simulation models are often used for the modeling and analysis of complex dynamic systems. Although traditional analysis methods such as design of experiments or optimization methods can be applied directly to data flow simulation models, applying these techniques to complex systems with large numbers of controllable inputs and performance measures may not be able to be completed in an acceptable amount of time. This research focuses on the development of optimization and analysis methods applied to graph-based meta-models of data flow simulation models. The goal of this research is to create a method that can efficiently determine the values of controllable system input variables that will yield user-specified system output performance measure values. The methodology utilizes an existing graph-based meta-modeling technique that elicits the graph structure of the underlying data flow simulation model. To enable goal-oriented optimization on the elicited graph, edge weights are determined by performing experimental sampling and utilizing a regression model to each of the nodes in the elicited graph. In the case of nonlinear input-output relationships, a method which provided piecewise linear edge weights is used. Finally, mathematical programming formulations are developed to conduct the goal-oriented optimization. An experimental performance evaluation is conducted and illustrates the capability of the method to efficiently provide estimates of system inputs that will result in desired values of system performance measures
Automatic Creation of Object Hierarchies for Ray Tracing
Intersection calculations dominate the run time of canonical ray tracers. A common algorithm to reduce the number of intersection tests required is the intersection of rays with a tree of extents, rather than the whole database of objects. A shortcoming of this method is that these trees are difficult to generate. Additionally, manually generated trees can be poor, greatly reducing the run-time improvement available. We present methods for evaluation of these trees in approximate number of intersection calculations required and for automatic generation of good trees. These methods run in O(nlogn) expected time where n is the number of objects in the scene. We report some examples of speedups
Bayesian Functional Data Analysis Using WinBUGS
We provide user friendly software for Bayesian analysis of functional data models using pkg{WinBUGS}~1.4. The excellent properties of Bayesian analysis in this context are due to: (1) dimensionality reduction, which leads to low dimensional projection bases; (2) mixed model representation of functional models, which provides a modular approach to model extension; and (3) orthogonality of the principal component bases, which contributes to excellent chain convergence and mixing properties. Our paper provides one more, essential, reason for using Bayesian analysis for functional models: the existence of software
THE NORTH CAROLINA MEDICAID PROGRAM: PARTICIPATION AND PERCEPTIONS AMONG PRACTICING ORTHODONTISTS. A 15-YEAR UPDATE.
This study was an update to a 2004 study that investigated the participation and perception of licensed, active orthodontists in the North Carolina Medicaid program. Im’s survey from 2004 was slightly modified and used for a direct comparison to their data to provide a 15-year update. Respondents were asked if they currently accepted new Medicaid patients. Additionally, ten commonly cited problems with the Medicaid program and patients that have been identified as barriers to participation were given. In 2019, twenty-four practitioners (37.5%) reported that they currently accept new Medicaid patients for treatment, a 56% increase by percentage from 2004 reporting of forty practitioners (24.1%). For all ten commonly cited problems, providers who never accepted Medicaid reported the problem to be a major problem more often than current Medicaid providers. From 2004 to 2019, changes in participation and perception of licensed, active orthodontists regarding the North Carolina Medicaid program were observed.Master of Scienc
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Electrical Conductivity and Gamma Ray Response to Clay, Water, and Chloride Content in Fissured Sediments, Trans-Pecos, Texas
Near-surface conductivity profiles determined using surface and borehole electromagnetic induction instruments were compared with each other and with variations in several important hydrological parameters, including clay content, water content, and chloride content in unsaturated sediments in fissured settings. Time-domain electromagnetic soundings were acquired at 10 boreholes in the Eagle Flat, Red Light Bolson, Hueco Bolson, and Ryan Flat areas in the arid Trans-Pecos region of West Texas. These boreholes were logged with induction and passive radiation probes to determine conductivity profiles and natural gamma ray activity. At the Red Light Bolson and Hueco Bolson fissures, the gamma logs were sensitive to clay content and followed the conventional trend of increasing count rates with increasing clay content. At Eagle Flat, gamma count rates were not much higher in the clay fraction than they were in the silt and sand fraction; thus, the gamma log underestimated the variability in clay content. At the Ryan Flat fissure, gamma count rates were higher than for the other fissure sites and were higher for the sand and silt fraction than for the clay fraction. This suggests that the sedimentary grains making up these deposits are volcanogenic and that the coarse fraction contains a larger percentage of K-bearing minerals than the clay fraction.Bureau of Economic Geolog
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