No description available.

A hydrological modelling effort using MODFLOW was undertaken in order to determine the relative importance of some of the factors influencing hydraulic gradient reversals in peatlands. Model domains were of two types, large raised bog type (LRBT) and kettle bog type (KBT), and were made to undergo various levels of meteorological forcing (water deficit). Substrate, too, was varied in order to determine its importance on reversals. Domain-wide reversals were successfully simulated in LRBT systems, but not in KBT systems. Although simulated flow patterns matched field-observed patterns, both pre- and post-drought, simulated reversals occurred more quickly than in the field. This may be due to insufficiently distributed parameters, such as hydraulic conductivity. Reversals were easily terminated by simulating non-drought conditions. In the LRBT system, reversal duration decreased, and time-to-reversal increased, with a decrease in drought severity. Increasing drought severity in KBT systems had the opposite effect on the duration of semi-reversed flow patterns, suggesting a possibly different/additional mechanism for flow reversals in KBT systems. Hydraulic conductivity had an appreciable effect on flow reversal evolution, though neither changing porosity, nor differences in catotelm layering had a great effect.

No description available.

No description available.

Natural ecosystems are dynamic and complex, with many being threatened by human activity. However, humans can also be at the root of a solution to this problem by developing ecosystem engineering which can be used to design, construct, modify, upgrade, repair, remediate, and maintain ecosystems. The aim of this project was to improve virtual ecosystems that can be used to increase the knowledge base for ecological engineering by studying adaptability as a factor for the success of species. This was done by analysing adaptive species in a virtual ecosystem, a computer application with which various configurations can be designed and studied in a closed environment. The virtual ecosystems used in this project represent ecosystems in general rather than any specific ecosystem, and allow for repeatable test cases to be run so that ecosystem dynamics can be studied. Adaptability was defined as the ability of an individual to adjust to a short term environmental pressure according to two factors: the adaptation speed, which is how fast an individual can respond to a change in environment, and the adaptive capacity, which is a quantitative indicator of how much the individual is able to adapt. In this project, experiments were performed to determine the effects of adaptability when applied to one aspect of individuals in an ecosystem. From the results of the experiments it was seen that the adaptation speed value could affect the success of a producer species in an ecosystem both positively and negatively. It was also found that ecosystems with both a consumer and producer species could persist longer when adaptability was incorporated into the individuals of the consumer species.

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No description available.

This research explores the complexities of database security, encompassing both the computer hardware and software. Also important is its nature as a people oriented issue. A risk analysis of a database system's security can be examined by creating a simulation model. Though, in order for it to be truly meaningful and accurate, all aspects of design, performance and procedure must be thoroughly and carefully scrutinized.Computer or data security is a major problem in today's world of data processing. This thesis outlines the security problem' and presents trends and issues. It also addresses current trends in computer security environments, database risk analysis, and simulations.Risk analysis is a technique used to quantitatively assess the relative value of protective measures. It is useful when appropriately applied and is in some cases required by regulatory agencies.The goal of security environments is to outline the framework which is valuable in assessing security issues and in establishing partitions in the overall environment within which this and other approaches to security can be examined.A simulation prototype is given which demonstrates the concepts of risk analysis for a database system. / Department of Computer Science

Although more emphasis is being placed on African Americans athletes, there are still disparities in the number of African American athletes compared to the number of African Americans in administrative positions. This study is based on the argument that supports the need for more African American in athletic administration positions, by examining the current hiring and retention of African American administrators and the critical issues underlying their employment.It is important to have more information readily available since there is such a large percent of African American athletes competing at institutions. Until the number of African American administrators is equitable to the number of participants creating revenue for their respective universities, there will always be a need for this study.This study utilized qualitative research methods to analyze interviews and survey data. The results of this study revealed that having role models, mentors, establishing a network, and enhancing enrollment and graduation rates of African Americans in graduate schools are key elements in increasing the numbers of African Americans in athletic administration positions. / Department of Physics and Astronomy

There is no abstract available for this thesis. / Department of Natural Resources and Environmental Management