\documentclass[11pt]{article} \setlength{\oddsidemargin}{0.0truein} \setlength{\evensidemargin}{0.0truein} \setlength{\textwidth}{6.5truein} \setlength{\topmargin}{0.0truein} \setlength{\textheight}{9.0truein} \setlength{\headsep}{0.0truein} \setlength{\headheight}{0.0truein} \setlength{\topskip}{10.0pt} \setlength{\parskip}{5mm} \usepackage{url} \usepackage{amsmath} \usepackage{amssymb} \pagestyle{empty} \begin{document} \begin{center} \textbf{\Large{\textsc{STANFORD UNIVERSITY}}}\\[5pt] \textbf{\Large{\textsc{DEPARTMENT OF STATISTICS}}}\\[5pt] \Large{\textsc{DEPARTMENTAL SEMINAR}} \end{center} % In the following statements, replace "Time of talk", % "Weekday", and "Date of talk". An example is provided. % If you are not sure about this, just skip this part. \begin{center} 4:15 p.m., Tuesday, April 15, 2008\\ %% Example: 4:15 p.m., Tuesday, February 13, 2007\\ Sequoia Hall Room 200\\ (Cookies at 3:45 in 1st Floor Lounge) \end{center} % In the following statements, replace "Name of the speaker" with your % name, "Department Affiliation" with your department affiliation, and %"University Affiliation" with your university affiliation. \begin{center} \textsl{Qiwei Yao} \\ London School of Economics \end{center} % In the following statements, replace "Title of the talk" % with your title of the talk. \begin{center} \subsection*{Analysing Time Series with Nonstationarity: Common Factors and Curve Series} \end{center} % In the following statements, replace "Abstract of the talk" % with your abstract. We introduce two methods for modelling time series exhibiting nonstationarity. The first method is in the form of the conventional factor model. However the estimation is carried out via expanding the white noise space step by step, therefore solving a high-dimensional optimization problem by many low-dimensional sub-problems. More significantly it allows the common factors to be nonstationary. Asymptotic properties of the estimation were investigated. The proposed methodology was illustrated with both simulated and real data sets. The second approach is to accommodate some nonstationary features into a stationary curved (or functional) time series framework. It turns out that the stationarity, though defined in a Hilbert space, facilitates the estimation for the dimension of the curved series in terms of a standard eigenanalysis. Please access the attached hyperlink for an important electronic communications disclaimer: http://www.lse.ac.uk/collections/secretariat/legal/disclaimer.htm \end{document}