About me

Contact me

My research

Courses

Humour

Fencing

Quote for the Day

Home

You've come to Doug Aberdeen's old pages. In 5 seconds you will taken to my new pages http://sml.nicta.com.au/~daa/

Assignment 3: Graphical Model Specialisations

Graphical models combine graph theory with statistical inference. They generalise a lot of useful algorithms. This assignment requires you to pick one such useful algorithm and summarise it in graphical model terms. The idea is to ensure you're familiar with graphical models and at least one of the common specialisations of them.

Suggestions for specialised algorithms to study are:

The list is not limited to these methods, but reflects the most well known specialisations. If you choose some other algorithm please ask me first.

In particular, your description should include:

  1. A line or two describing the kinds of applications the specialisation can be used for.
  2. A description of the random variables in the graphical model, which are observed and which are hidden?
  3. How are the probability distributions are represented, i.e., tables, gaussians, or some other parameterised distribution?
  4. The structure of the graphical model (diagram please).
  5. How the specialised algorithm uses the sum-product algorithm (and/or max-product algorithm) used for undirected acyclic graphs (tree structures), including
    1. what form do the messages take;
    2. which are the backward messages, which are the forward messages;
    3. what are the separating set variables;
    4. what efficiencies (if any) are introduced when considering the specialised problem (hint, try constructing small instances and generating the moralised graph and corresponding junction tree);
  6. Does the specialised algorithm learn anything e.g., change any parameters? If so, what part of the gaphical model is being learnt and for what reason? How does the learning algorithm meld with the inference algorithm?
Some of these questions don't make sense for some specialisations. If so you should explain why. I imagine these assignments will be about 2 pages and will require a significiant amount of reading. Unless you have particularly neat handwriting I would appreciate this assignment being typed.
The views and opinions expressed on this web page are not necessarily those of NICTA or the Australian National University. Any HTML or image from this page may be copied and re-used freely but must not be sold.
Feedback:Doug.Aberdeen AT anu.edu.au