Unsupervised Learning 2001 Course Web Page

Gatsby Computational Neuroscience Unit
University College London

MSc Intelligent Systems

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SEE THIS YEAR'S COURSE: [2002]

Code: COMPGI02

Year: MSc in Intelligent Systems, Gatsby Unit Core Course

Prerequisites: Some background in statistics, calculus, linear algebra, and computer science. Any student or researcher at UCL is welcome to attend the lectures. Students wishing to take it for credit should consult with the course lecturers (email: zoubin @ gatsby.ucl.ac.uk ).

Term: 1

Time: 10.00 to 13.00 Tuesdays

Location: Cruciform Building Room 2.01

Taught By:

Zoubin Ghahramani (50%)
Carl E Rasmussen (50%)
Oct 2:
Introduction and Statistical Foundations
  • Maximum Likelihood
  • Bayesian learning
  • The relation to coding  length
  • Supervised vs Unsupervised vs Reinforcement Learning
Lecture Slides [ps.gz] [pdf]
Assignment [ps.gz] [pdf]
Oct 9:
Latent Variable Models
  • Mixture of Gaussians (MoG) and k-means
  • Factor Analysis (FA) and PCA
Lecture Slides [ps.gz] [pdf]
Assignment [ps.gz] [pdf]
Suggested Readings:
Welling Class Notes [ps.gz] [pdf]
Roweis and Ghahramani article [ps.gz] [pdf]
Minka linear algebra notes
Oct 16:
The EM Algorithm
  • General Theory
  • Application to MoG and to FA
  • Extensions
Lecture Slides: [ps.gz] [pdf]
Assignment [ps.gz] [pdf]
Matlab Code: mog.m, plot_gaussian.m
Data: train1.mat
Oct 23:
Latent Variable Time Series Models
  • Hidden Markov Models (HMMs)
  • Forward-Backward and Viterbi
  • Linear Dynamical Systems
  • Kalman Filtering (KF) and Extended KF
  • Hybrid and Nonlinear Time Series Models
Lecture Slides: [ps.gz] [pdf]
Assignment [ps.gz][pdf]
Geyser Data Set: geyser.txt
LDS Code: lds.tar.gz, rdiv.m
Oct 30:
Introduction to Graphical Models
  • Conditional Independence
  • Markov Networks
  • Hammersley-Clifford Theorem
  • Bayesian Networks
  • Belief Propagation
Lecture Slides: [ps.gz] [pdf]
Assignment [ps.gz][pdf]
Reading: Chapter 4 of Pearl (1988)
Nov 13:
Hierarchical and Nonlinear Models
  • Independent Components Analysis (ICA)
  • Sigmoid Belief Networks
  • Boltzmann Machines
Lecture Slides: [pdf]
Reading: Welling Notes on ICA
Assignment: [ps.gz] [pdf]
Nov 20:
Sampling Methods and Variational Approximations
  • Importance Sampling
  • Gibbs Sampling
  • Metropolis 
  • Hybrid Monte Carlo and other methods
  • Variational Approximations
  • Application to Mixture of Factor Analysers
Lecture Slides (MCMC): [pdf]
Lecture Slides (Variational): [pdf]
Assignment: [pdf]
Data: lindata.mat
Suggested Readings: Radford Neal's Technical Report; and Jordan et al's Introduction to Variational Methods
Nov 27:
Gaussian Processes
  • Derivations as infinite neural networks, Bayesian kernel machines, and priors in function space
  • Inference in GPs
  • Approximate Methods
  • GP Classifiers
Lecture Slides: [pdf]
Assignment: [ps.gz] [pdf]
Matlab Code: minimize
Data: motorcycle.txt
Dec 11:
Reinforcement Learning
  • Markov Decision Problems
  • The Bellman Equation
  • Temporal Difference and Q-learning
  • Relation to Optimal Control and Influence Diagrams
.

Aims: This course provides students with an in-depth introduction to unsupervised learning techniques. It presents probabilistic approaches to modelling and their relation to coding theory and Bayesian statistics. A variety of latent variable models will be covered including mixture models (used for clustering), dimensionality reduction methods, time series models such as hidden Markov models which are used in speech recognition and bioinformatics, independent components analysis, hierarchical models, and nonlinear models.  The course will  present the foundations of probabilistic graphical models (e.g. Bayesian networks and Markov networks) as an overarching framework for unsupervised modelling. We will cover Markov chain Monte Carlo sampling methods and variational approximations for inference. Time permitting, students will also learn about Gaussian processes and the fundamentals of Bayesian decision theory/reinforcement learning/optimal control.

Learning Outcomes:  To be able to understand the theory of unsupervised learning systems; to have in-depth knowledge of the main models used in UL; to understand the methods of exact and approximate inference in probabilistic models; to be able to recognise which models are appropriate for different real-world applications of machine learning methods.

Method: Lecture presentations with associated class problems.

Assessment:

Course Location:

Cruciform Building Room 2.01
University College London
Tuesdays 10:00 - 13:00

Tel:

Zoubin   020 7679 1199
Carl     020 7679 1198

Email:

zoubin@gatsby.ucl.ac.uk
edward@gatsby.ucl.ac.uk

Information here was last updated Oct 2001.