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Full-Text Articles in Physical Sciences and Mathematics
Information Metrics For Predictive Modeling And Machine Learning, Kostantinos Gourgoulias
Information Metrics For Predictive Modeling And Machine Learning, Kostantinos Gourgoulias
Doctoral Dissertations
The ever-increasing complexity of the models used in predictive modeling and data science and their use for prediction and inference has made the development of tools for uncertainty quantification and model selection especially important. In this work, we seek to understand the various trade-offs associated with the simulation of stochastic systems. Some trade-offs are computational, e.g., execution time of an algorithm versus accuracy of simulation. Others are analytical: whether or not we are able to find tractable substitutes for quantities of interest, e.g., distributions, ergodic averages, etc. The first two chapters of this thesis deal with the study of the …
Variable Selection In Single Index Varying Coefficient Models With Lasso, Peng Wang
Variable Selection In Single Index Varying Coefficient Models With Lasso, Peng Wang
Doctoral Dissertations
Single index varying coefficient model is a very attractive statistical model due to its ability to reduce dimensions and easy-of-interpretation. There are many theoretical studies and practical applications with it, but typically without features of variable selection, and no public software is available for solving it. Here we propose a new algorithm to fit the single index varying coefficient model, and to carry variable selection in the index part with LASSO. The core idea is a two-step scheme which alternates between estimating coefficient functions and selecting-and-estimating the single index. Both in simulation and in application to a Geoscience dataset, we …