# UHCL Faculty Works (Abstracts Only)

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# Browsing UHCL Faculty Works (Abstracts Only) by Author "Feagin, Terry"

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Item Analytical Position and Velocity Partials for Conic and Non-Conic Trajectories(AAS Paper, 2017-02) Feagin, TerryItem Edge effects in lacunarity analysis(Ecological Modelling, 2007) Feagin, TerryLacunarity results can be skewed by edge effects and this may have negative implications for research projects in ecological pattern analysis and modeling. The problem occurs because the standard gliding-box algorithm over-samples the center of a map and under-samples along its edges. This effect is particularly strong when the scale of inquiry is large relative to the extent of the map, as fewer box mass estimates are utilized to form the distribution from which lacunarity is calculated. We devised a new algorithm where we allowed the gliding-box to overlap beyond the edge of the map and wrap back around to the opposing side, thereby solving both problems. In this study, we compare the standard lacunarity algorithm with this new periodic boundary algorithm (a method often used in cellular automata modeling) to quantify the differences between the two approaches and to determine when the standard algorithm may suffer from deleterious effects. We performed our analysis upon several neutral landscapes to evaluate the importance of pattern as well. We found that the standard algorithm skews results when the pattern is strongly heterogeneous or aggregated, especially when the classes are not evenly distributed around the center of the map or when percent cover pi is low. The advantages and disadvantages of both algorithms, as well as other potential remedies such as up-weighting samples along the edges, are discussed.Item The efficient solution of Kepler’s equation using a quartic approximation and rational functions(Neural, Parallel & Scientific Computations, 2016-12) Feagin, TerryItem An Explicit Runge-Kutta Method of Order Fourteen(Numerical Algorithms, 2009) Feagin, TerryItem GOLDS, a Blackboard System for Fault Diagnosis(Third CLIPS Conference Proceedings, 1994-09-14) Feagin, TerryItem High-order Explicit Runge-Kutta Methods Using M-Symmetry(Neural, Parallel & Scientific Computations, 2012-12) Feagin, TerryThe Runge-Kutta equations of condition are reformulated. The concept of m-symmetry is defined. It is shown that any m-symmetric method is of order m. The equations of condition for a twelfth-order explicit Runge-Kutta method with twenty-five stages are solved using m-symmetry. The method contains an embedded tenth-order method that can be used to estimate the local truncation errors and thus to vary the stepsize. Numerical experiments demonstrate that the method compares favorably with other high-order methods, especially for those problems requiring highly accurate solutions.Item A Tenth-Order Runge-Kutta Method with Error Estimate(Proceedings of the IAENG Conf. on Scientific Computing, 2007) Feagin, TerryA tenth-order explicit Runge-Kutta method with embedded results of order eight is exhibited. The difference between the results of orders eight and ten can be used to estimate the local truncation error and thus to vary the stepsize. Numerical experiments demonstrate that the method compares favorably with other high-order embedded methods.Item A Tutorial on CLIPsTOOL, a Graphical Interface to CLIPS(Third CLIPS Conference Proceedings, 1994-09-14) Feagin, Terry