Master of Science, University of Akron, 2017, Applied Mathematics

Combinatorial methods have proved to be useful in generating relaxations of polytopes in various areas of mathematical programming. In this work, we propose a discrete-integer linear programming model for a recent version of the Phylogeny Estimation Problem (PEP), known as the Balanced Minimal Evolution Method (BME). We begin by examining an object known as the Balanced Minimal Evolution Polytope and several classes of geometric constraints that result in its relaxation. We use this information to develop the linear program and propose two Branch and Bound algorithms to solve the model. The second algorithm takes advantage of a heuristic known as a large neighborhood search. We provide experimental results for both algorithms, using perfect and noisy data, as well as suggestions for further improvement.

Committee: Stefan Forcey Dr. (Advisor); Malena Espanol Dr. (Committee Member); Patrick Wilber Dr. (Committee Member) Subjects: Applied Mathematics; Biology

Master of Science, The Ohio State University, 2010, Natural Resources

During presettlement times, many Eastern deciduous forests in North America are thought to have been open park-like woodlands rather than the closed-canopy, second-growth forest encountered today. Changes in forest structure are of special concern given that oaks (Quercus spp.) cannot regenerate effectively in closed-canopy stands. Partial-harvesting is one management technique used to simulate historic disturbance regimes and restore a more open forest structure. I studied forest songbirds in shelterwoods recently harvested to 50% stocking and reference upland mixed-oak stands in the same landscape context. My research was conducted at four state forests in southern Ohio from 2007–2009. I focused on canopy songbirds as one late-successional group that could benefit from partial-harvesting. Specifically I examined the extent to which (1) canopy species select particular canopy features and (2) canopy structure affects reproductive success. Distance-based line-transect surveys showed that shelterwood harvesting shifted the bird community from midstory and ground-nesting species to shrub and canopy-nesting species. The declining Cerulean Warbler (Dendroica cerulea) favored northeast facing slopes with abundant grapevine. Nesting success of canopy species was comparable between partially-harvested and reference stands, although generally low (15–36%) even in a predominantly forested landscape. Canopy structure was important and overall species nested in areas with fewer medium trees (23–38 cm dbh). In addition, species selected white oaks and avoided red oaks which were negatively associated with nesting success. Management implications from this study include prioritization of areas for protection, and recommendations on size and species of trees retained in partial-harvests. Results suggest that shelterwood harvesting can provide suitable breeding habitat for canopy songbirds in the short-term, although long-term management options should be considered.

Committee: Amanda Rodewald PhD (Advisor); Roger Williams PhD (Committee Member); Paul Rodewald PhD (Committee Member) Subjects: Ecology; Forestry

Doctor of Philosophy, The Ohio State University, 2010, ED Policy and Leadership

This dissertation is a comparative study, using a criterion-group design, examining the effectiveness of a blended instructional model and a distance instructional model in the teaching of a learning and motivation strategies class. Course effectiveness was determined based upon changes in student grade point averages over time from prior to course enrollment to one term beyond course completion. In addition to grade point averages, other student characteristics and demographics were examined for commonalities and differences between and among students in the two different instructional methods. Characteristics and demographics considered include: procrastination scores, Preferred Learning Orientation, age, gender, ethnicity and academic ranking. The course used in this study is a college-level, credit-bearing elective course. The data used in this study suggests there is no significant difference between the blended version and the distance version of the course in terms of student GPA. In addition, there appears to be no significant differences in demographics. While students in the distance course are older and further advanced academically (this being consistent with other findings in distance education), the male-female ratio, ethnicity distributions, and scores on self-administered procrastination and learning orientation surveys are all approximately the same in the blended version as in the distance version of the course.

Committee: Bruce Tuckman (Advisor); Anita Woolfolk-Hoy (Committee Member); Leonard Baird (Committee Member) Subjects: Education; Educational Psychology; Higher Education