Physical Sciences and Mathematics Commons^™

Graph Products And Covering Graph Imbeddings, Ghidewon Abay Asmerom

Dissertations

No abstract provided.

Improving Networks Reliability, Jamal H. Nouh

Dissertations

No abstract provided.

On Distance In Graphs And Digraphs, Songlin Tian

Dissertations

One of the most basic concepts associated with a graph is distance. In this dissertation some new definitions of distance in graphs and digraphs are introduced. One principle goal is to extend certain known results involving the standard distance function on graphs to the field of digraphs with an appropriate concept of distance. Several parameters as well as subgraphs and subdigraphs defined in terms of distance are investigated.

Chapter I gives a brief overview of the history of distance and generalized distance in graphs. By presenting a listing of major results in this area, it provides a background for the …

The Enumeration Of Graph Imbeddings, Robert G. Rieper

Dissertations

Graphs can be drawn on surfaces. Here, graphs may have multiple edges or loops (pseudographs), the surfaces are closed orientable 2-manifolds (sphere, torus, etc.) and their generalizations (pseudosurfaces and generalized pseudosurfaces), and the drawings are 2-cell imbeddings. For quite some time it has been known that a connected graph has $\rm \Pi(degree(\upsilon)-1)$! 2-cell imbeddings on surfaces. More detailed information about these imbeddings has been wanting. In addition, many of the imbeddings counted above 'look the same' when all vertex and edge labels are removed. The resulting unlabeled imbeddings are fewer in number and more difficult to enumerate than their labeled …

Enumerating The Orientable 2-Cell Imbeddings Of Complete N-Partite Graphs, Bruce P. Mull

Dissertations

This dissertation develops formulas for the number of congruence classes of maps of complete, complete bi-partite, complete tripartite, and complete n-partite graphs; these congruence classes correspond to unlabeled imbeddings. The method employed for the enumeration is an extension of that used by Mull, Rieper, and White in 1988. We let the automorphism group act on the set of rotations and use Burnside's Lemma to count orbits for these rotations. Compatible permutations are introduced to determine those automorphisms actually contributing to the number of orbits.

The complete n-partite formula is shown to generalize those of the other three families of graphs. …

The Fokker-Planck And Related Equations In Theoretical Population Dynamics, George Derise

Mathematics & Statistics Theses & Dissertations

The population growth of a single species is modeled by a differential equation with initial condition(s) so that the number of organisms in the population is derived using some mechanism of growth, i.e. a growth rate function. However, such deterministic models are often highly unrealistic in population dynamics because population growth is basically a random event. There are a large number of chance factors influencing growth that might not be taken into account by deterministic models. The effect of other species (for example, in the chance meeting of a predator), population fluctuations due to weather changes that would alter food …

A Mathematical Model Of The Dynamics Of An Optically Pumped Codoped Solid State Laser System, Thomas G. Wangler

Mathematics & Statistics Theses & Dissertations

This is a study of a mathematical model for the dynamics of an optically pumped codoped solid state laser system. The model comprises five first order, nonlinear, coupled, ordinary differential equations which describe the temporal evolution of the dopant electron populations in the laser crystal as well as the photon density in the laser cavity. The analysis of the model is conducted in three parts.

First, a detailed explanation of the modeling process is given and the full set of rate equations is obtained. The model is then simplified and certain qualitative properties of the solution are obtained.

In the …

Boundary Value Problems In Elasticity And Thermoelasticity, Stuart Davidson

Mathematics & Statistics Theses & Dissertations

In this dissertation the author solves a series of mixed boundary value problems arising from crack problems in elasticity and thermoelasticity. Using integral transform techniques and separation of variables appropriately, it is shown that the solutions can be found by solving a corresponding set of triple or dual integral equations in some instances, while in others the solutions of triple or dual series relations are required. These in turn reduce to various singular integral equations which are solved in closed form, in two cases, or by numerical methods. The stress intensity factors at the crack tips, the physical parameters of …

The Truncated Cauchy Distribution: Estimation Of Parameters And Application To Stock Returns, Paul G. Staneski

Mathematics & Statistics Theses & Dissertations

The problem addressed in this dissertation is the existence and estimation of the parameters of a truncated Cauchy distribution. It is known that when a number of distributions with infinite support are truncated to a finite interval that the maximum likelihood estimator of the scale parameter fails to exist with positive probability. In particular, necessary and sufficient conditions which give rise to instances of non-existence have been found for the exponential (Deemer and Votaw (1955)), gamma (Broeder (1955), Hegde and Dahiya (1989)), Weibull (Mittal and Dahiya (1989)) and normal distribution (Barndorff-Nielsen (1978), Mittal and Dahiya (1987), Hegde and Dahiya (1989)). …

A Generalization Of Linear Multistep Methods, Leon Arriola

Mathematics & Statistics Theses & Dissertations

A generalization of the methods that are currently available to solve systems of ordinary differential equations is made. This generalization is made by constructing linear multistep methods from an arbitrary set of monotone interpolating and approximating functions. Local truncation error estimates as well as stability analysis is given. Specifically, the class of linear multistep methods of the Adams and BDF type are discussed.