Graduate Student Seminar

Speaker 1: Juyoung Jeong

Title

Differentiability and Subdifferentiability of Spectral Functions

Abstract

A spectral function of a symmetric matrix A is a function which depends only on the eigenvalues of A; hence it can be written as the composition of a permutation invariant function with the eigenvalue mapping. Although it is crucial to know the gradient of an objective function in matrix optimization problem, it is often very difficult to actually calculate it. In this talk, we will see how we can calculate the gradient of a spectral function just by looking at the gradient of the corresponding permutation invariant function. The Fenchel conjugate, convexity, and subdifferential of spectral functions are also discussed.

Speaker 2: Michael Lucagbo

Title

SEC 2012: The New Philippine Socioeconomic Classification

Abstract

Socioeconomic classification (SEC) is an important construct aimed at capturing and understanding changes in the structure of a society. The task of classifying Philippine households according to their SEC has been tackled anew in a collaborative work between the Marketing and Opinion Research Society of the Philippines (MORES), the Philippine Statistics Authority (PSA) and the University of the Philippines School of Statistics. Data consisting of 36,812 households from the 2009 Family Income and Expenditure Survey (FIES) are used.  Nine SECs are obtained using nonhierarchical cluster analysis. A list of household characteristics used as determinants of the SECs is developed using the ordinal logistic regression model. Lastly, an instrument for implementation in the field is proposed to predict a household’s true SEC.