Natural language processing (NLP) went through a profound transformation in the mid-1980s when it shifted to make heavy use of corpora and data-driven techniques to analyze language. Since then, the use of statistical techniques in NLP has evolved in several ways. One such examp…
This book combines a model reduction technique with an efficient parametrization scheme for the purpose of solving a class of complex and computationally expensive simulation-based problems involving finite element models. These problems, which have a wide range of important app…
The southern portion of the Prairie Pothole Region (PPR), including the Des Moines Lobe of northwest and north-central Iowa, is predicted to become increasingly important to breeding waterfowl as climatic changes drive a southeastward shift in wetland distribution. The history o…
Fitness variation among individuals is a key tenet of eco-evolutionary theory, as natural selection acts upon this variation to bring about evolutionary change. Our understanding of individual heterogeneity and its evolutionary consequences in wild populations is limited, partic…
This dissertation comprises three essays on latent variable models and Bayesian statistical methods for the study of American legislative institutions and the more general problems of measurement and model comparison. In the first paper, I explore the dimensionality of latent va…
Air pollution is an important determinant of health. There is convincing, and growing, evidence linking the risk of disease, and premature death, with exposure to various pollutants including fine particulate matter and ozone. Knowledge about the health and environmental risks a…
In binary-transaction data-mining, traditional frequent itemset mining often produces results which are not straightforward to interpret. To overcome this problem, probability models are often used to produce more compact and conclusive results, albeit with some loss of accuracy…
Acoustic survey techniques are widely used to quantify abundance and distribution of a variety of pelagic fish such as herring (Clupea harengus). The information provided is becoming increasingly important for stock assessment and ecosystem studies, however, the data collected a…
Traffic safety during winter seasons has been a serious concern in Iowa as hundreds of people are injured on Iowa's highways each winter. As the goal of the state transportation agency is to ensure the mobility of road users without compromising the safety during winter periods,…
There is a long and rewarding history in astronomy of studying the motions of stars, gas, and planets to learn about the distribution of mass in the universe. Observations of nearby galaxies rotating faster than otherwise expected are one of the pillars of evidence for the cold …