Digital Commons Network^™

Transportation Shortest Path Search Area Model, Hui Wang

Doctoral Dissertations

Although many studies on shortest-path algorithms have been conducted in the past, few of them have considered the time and effort required to obtain and update the weight property of the network arcs. For transportation-related problems – due to the size and complexity of the network – preparing, updating, and transmitting the network database on which the shortest-path algorithms perform can be a challenge.

This study designed a Transportation Shortest Path Search Area (TSPSA) model to enhance the database preparation and updating step before any shortest-path search algorithm can start processing. Taking advantage of the characteristics of the transportation networks, …

Assessment And Redesign Of The Synoptic Water Quality Monitoring Network In The Great Smoky Mountains National Park, Kenneth Ray Odom

Doctoral Dissertations

The purpose of this study was to assess and redesign an existing 83-site synoptic water quality monitoring network in the Great Smoky Mountains National Park. The study involved a spatial analysis of water quality data (pH, ANC, conductivity, chloride, nitrate, sulfate, sodium, and potassium), watershed characteristics (geology, morphology, and vegetation), and collocated site information to determine which sites were redundant and a temporal analysis to determine the effectiveness of the current sampling frequency to detect long-term trends. The spatial analysis employed a simulated annealing algorithm using the variable costs of the network and the results of multivariate data techniques to …

Impacts Of Environmental Factors On Flexible Pavements, Gang Zuo

Doctoral Dissertations

Mechanistic-empirical pavement design methods for flexible pavements are based on the assumption that the pavement life is inversely proportional to the magnitude of the traffic-induced pavement strains. These strains vary with the stiffness of the asphalt layer and underlying base layer and subgrade. Environmental factors, such as the temperature in the asphalt concrete layer and the water content in the base layer and the subgrade, have a significant impact on the stiffness of relevant layers in pavement systems, and consequently the estimated life of flexible pavements. A comprehensive instrumentation system was installed at four sites across the state of Tennessee …

Probabilistic Based Design Of Frp Structures, Maha Khader Alqam

Doctoral Dissertations

This thesis presents the results of an analytical probabilistic based design procedure for concentrically loaded compression members and simply supported beams of fiber-reinforced polymeric (FRP) composite materials. Resistance factors for use in an LRFD format are developed for columns for both flexural buckling and local buckling of doubly symmetric sections, both flexural buckling and flexural-torsional buckling of equal leg angles, and material failure. Resistance factors are developed for lateral-torsional buckling of simply supported doubly symmetric beams loaded with concentrated vertical loads at mid-spans. The developed resistance factors are a function of the coefficient of variation of the appropriate material properties. …