This dissertation research addresses how to detect structural changes in stochastic linear models. By introducing a special structure to the design matrix, we convert the structural change detection problem to a variable selection problem. There are many existing variable selection strategies, however, they do not fully cope with structural change detection. We design two penalized regression algorithms specifically for the structural change detection purpose. We also propose two methods involving these two algorithms to accomplish a bi-level structural change detection: they locate the change points and also recognize which predictors contribute to the variation of the model structure. Extensive simulation studies are shown to demonstrate the effectiveness of the proposed methods in a variety of settings. Furthermore, we establish asymptotic theoretical properties to justify the bi-level detection consistency for one of the proposed methods. In addition, we write an R package with computationally efficient algorithms for detecting structural changes. Comparing to traditional methods, the proposed algorithms showcase enhanced detection power and more estimation precision, with added capacity of specifying the model structures at all regimes.
Structural change detection via penalized regression
Abstract
Details
- Title: Subtitle
- Structural change detection via penalized regression
- Creators
- Bo Wang - University of Iowa
- Contributors
- Kung-Sik Chan (Advisor)Joseph Lang (Committee Member)Joyee Ghosh (Committee Member)Aixin Tan (Committee Member)Patrick Breheny (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Statistics
- Date degree season
- Summer 2018
- DOI
- 10.17077/etd.siecbxeb
- Publisher
- University of Iowa
- Number of pages
- x, 144 pages
- Copyright
- Copyright © 2018 Bo Wang
- Language
- English
- Description illustrations
- illustrations
- Description bibliographic
- Includes bibliographical references (pages 142-144).
- Public Abstract (ETD)
This dissertation tackles with stochastic linear models with structural changes. When structural changes occur in stochastic linear models, some common questions arise, such as when these changes happen, which variables change at these change points, and what the model structures look like before and after these change points. We address these questions in this dissertation. We propose two novel approaches to detect structural changes. Comparing to traditional approaches which only estimate the locations of the change points, our proposed methods not only demonstrate higher accuracy in change point estimation, but also simultaneously identify the changed variables, and specify model structures at all regimes. We demonstrate the effectiveness of our methods when dealing with various models, including the ones that have some model specification issues. We also proved that the estimated change points and changed variables are close to their true values at a large sample size. Lastly, we write an R package to automatically output the change points and changed variables, as well as the model structures at all regimes.
- Academic Unit
- Statistics and Actuarial Science
- Record Identifier
- 9983776622602771