Focused Multi-task Learning Using Gaussian Processes

Our next speaker for HIIT Otaniemi seminar series is Jaakko Peltonen from the "Statistical Machine Learning and Bioinformatics" group of the Helsinki Institute for Information Technology HIIT.

All ICS@Aalto researchers are also warmly welcome to attend the seminar!

HIIT Otaniemi Seminar, Monday September 19, 13:15
Location: Computer Science Building, Hall T2

Jaakko Peltonen
Statistical Machine Learning and Bioinformatics Group
Helsinki Institute for Information Technology HIIT
Department of Information and Computer Science
Aalto University School of Science

Title:
Focused Multi-task Learning Using Gaussian Processes

*** This work by Gayle Leen, Jaakko Peltonen, and Samuel Kaski won the Award for Best Paper in Machine Learning at ECML PKDD 2011, the European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases. ***

Abstract:
Given a learning task for a data set, learning it together with related tasks (data sets) can improve performance. Gaussian process models have been applied to such multi-task learning scenarios, based on joint priors for functions underlying the tasks. In previous Gaussian process approaches, all tasks have been assumed to be of equal importance, whereas in transfer learning the goal is asymmetric: to enhance performance on a target task given all other tasks. In both settings, transfer learning and joint modeling, negative transfer is a key problem: performance may actually decrease if the tasks are not related closely enough. In this paper, we propose a Gaussian process model for the asymmetric setting, which learns to “explain away” non-related variation in the additional tasks, in order to focus on improving performance on the target task. In experiments, our model improves performance compared to single-task learning, symmetric multi-task learning using hierarchical Dirichlet processes, and transfer learning based on predictive structure learning.

Welcome! 

-- 
Mehmet Gönen
Helsinki Institute for Information Technology HIIT
Department of Information and Computer Science
Aalto University School of Science