Statistics

One of the most important tasks in biophysics is to understand proteins. It has long been observed that sequence similarity, structural similarity, and functional similarity among proteins are highly correlated. Inspired by this observation, sequence comparison is often employed to retrieve similar/related protein sequences. However, the central issue of assigning statistical significance to the proteins retrieved remains a challenging problem. How a directed polymer/percolation model can shed light in understanding the statistics of global sequence alignments, which is also the fundamental building block for multiple sequence alignment in many multiple alignment applications, is revealed in my thesis. In terms of understanding proteins' specific functionality, it is essential to know how protein sequences determine their unique three dimensional structures and folding kinetics. A careful analysis of the amino acid arrangements in proteins with known structures may provide insights to this issue. In my thesis, I will present a statistical analysis on tertiary contacts to gain more accurate estimates of the preference of amino acid interactions. This analysis reveals an unusually large contact between cysteines, indicating an effective attractive potential among them. The nontrivial role of cysteine-cysteine interactions in protein folding is discussed in my thesis. A new concept termed target-focusing is also introduced.

Recently, empirical attention has been directed toward understanding public opinion about gun control laws. Despite this focus, three gaps are evident in extant scholarship. First, few current examinations have relied on recently collected, national data to explore predictors of public attitudes. Second, relatively little work systematically investigates whether type of weapon bans (e.g. handgun versus semi-automatic weapon) affects public support for a given gun control initiative. Third, and importantly, the general focus in prediction support for gun control measures has been on social and demographic factors. Little is known from a theoretical perspective about how other variables - such as knowledge of Constitutinal issues or perceptions of the U.S. Supreme Court - affect public attitudes toward gun control. Using national poll data collected in 2011 by Time magazine, this study addresses these research gaps by estimating several logistic regression analyses. Research and policy implications are discussed.

The demand on transportation infrastructure is dramatically increasing due to population growth causing the transportation systems to be pushed to their limits. With the projected population growth, not only for the U.S. but especially for the higher education field, university campuses are of great importance for transportation engineers. Urban univeristy campuses are considered major trip generators and with the population forecast many challenges are bound to arise. The implementation of an improved transit system provides a lower-cost solution to the continuously increasing congestion problems in university campus road networks and surrounding areas. This paper presents a methodology focused on the development of a hybrid system concentrated in three main aspects of transit functionality : access to bus stop location, reasonable travel time and low cost. Two methods for bus stop locations assessment are presented for two levels of analysis : microscopic and mesoscopic. The resulting travel time from the improved bus stop locations is analyzed and compared to the initial conditions by using a microsimulation platform. The development of a mathematical model targets the overall system's cost minimization, including user and operator cost, while maximizing the service coverage. The results demonstrate the benefits of the bus stop assessment by the two applied methods, as well as, the benefits of the route and headway selection based on the mathematical model. Moreover, the results indicate that the generation of routes using travel time as the impedance factor generates the optimal possible routes to obtain the minimum system's overall cost.