## Winter 2002

### Goals

The main goal of the project is to allow you to study more in-depth probabilistic reasoning techniques described in class. A secondary goal is to help you develop your research skills (reviewing research literature, formulating questions, deciding on a theoretical or empirical approach to answer them, writing up your findings). Ideally, the project topic you choose should be related to your research interests.

There are three main categories of projects:

• Applying probabilistic to interesting problem domains, thereby allowing you to gain in-depth experience with specific algorithms.
• Studying probabilistic reasoning techniques not covered or skimmed in class
• Investigating theoretical issues.

Ideally, the projects would be individual. However, teams of two people would be accepted under special circumstances. If you choose to team up, there should be a clear delimitation between the work of that each person does. Both students should turn in separate write-ups.

I strongly encourage you to perform some experiments as part of your project, in order to gain practical experience with probabilistic reasoning algorithms. Many algorithms are available free from universities and research labs, so you would not have to code them. The resources web page should help you find both papers and software as needed.

### Project themes

If you are already have a research topic in mind, feel free to propose it. Otherwise, you can choose a topic from the list below (which is ordered fairly randomly). If no topic suits your interest, please make an appointment to discuss alternatives.

Proposed topics:

• Probabilistic reasoning applied to a problem domain
Such a project will involve describing the problem you have in mind, formulating it appropriately for probabilistic reasoning, summarizing existing literature that attempted to solve this problem using probabilistic methods and/or coming up with a solution yourself. For such a project, you have to experiment with at least an algorithm of your choice
• Learning in active vision
The problem of active vision investigates where the focus of attention should be in order to gather as much information as possible about the task at hand. Reinforcement learning and Bayesian methods are adequate for this task.
• Structured action representations in MDPs
As we will discuss in class, a lot of work in MDPs/RL has been devoted to structured state space. But a lot less literature exists on structured action descriptions. This is a research-oriented project, involving a study on the literature regarding action representations, and a proposal for how to do planning/learning with richer action representations.
• Effect of exploration strategies in reinforcement learning.
There is a great variety of exploration strategies in RL, varying from very straightforward methods (such as Boltzmann exploration or epsilon-greedy) to methods very well-motivated, such as Singh and Kearns' E3 algorithm. The project would involve surveying and comparing existing methods.
• Effect of eligibility traces in reinforcement learning
Eligibility traces can significantly speed up reinforcement learning. In class we discuss only one version (accumulating traces) but several have been proposed. The project will especially involve looking a variable eligibility trace parameters.
• Function approximation in reinforcement learning
This involves surveying the existing methods and theoretical results, and comparing different algorithms
• Yahtzee
For the game-minded people, this is a great application of probabilities, and it does not need to involve an opponent. I am interested in finding optimal policies for the whole game, or part of it. The game is slightly too big to solve exactly, I think, which makes it interesting. If several people are interested, we can have a tournament too.
• Hierarchical Hidden Markov Models
We discussed the basics of HMMs in class. Hierarchical HMMs can be more efficient than flat ones. This project will involve describing how the HMM inference procedures are done in hierarchical HMMs, and doing one experiment with hierarchical HMMs (possibly describing other existing applications).
• Importance sampling and particle filtering in RL
We talked a bit in class about how these methods are used with RL. The project involves looking at the current approaches and identifying others (this is a research-oriented topic).
• Using structured CPTs in Bayes nets
This is a very useful technique, but we had no time to discuss it. The project involves surveying existing techniques, presenting how they affect the Bayes net inference algorithms, and experimenting with structured CPTs on a Bayes net of your choice.
• Survey of algorithms for dealing with loops in beliefs nets
We talked about this issue in class, but we only really covered variable elimination and a bit on junction trees. I am interested in a survey of the other techniques, and comparison.
• MCMC methods and applications
We just touched on the very basic in class, Gibbs sampling is the simplest MCMC methods. The project would be to look at more sophisticated methods and applications.
• Efficient EM approaches
Again, we just talked about the basic EM idea in class. The project should cover more sophisticated approaches.

### Format and dates

Please send me by e-mail by Monday, March 25, a brief project description, specifying the topic you want to address, why you are interested in it, a rough plan of what you will do and five references you think might be useful. You do not have to read the papers before the proposal, nor do you have to include them in your final bibliography, if they end up not being relevant. The main purpose of this document is to inform me of your intentions, so I can give you feedback on the scope of the work.

Project report.
The report should be approximately 10 pages long (this requirement is just to get you oriented; do not take it as a hard restriction). The format should be similar to the research papers we have been reading during the semester. It should contain the following information:

• A description of the topic and why you were interested in it
• A review of related literature; this should include at least 5 papers relevant to your topic. If you want help seeking such papers, let me know.
• One or more specific questions that you wanted to investigate
• The methodology you decided to follow (e.g. theory or experiments, what kind of experiments, etc.)
• An analysis of your findings
• Conclusion and possible future work directions
The due date for the report is April 30.

Prof. Doina PRECUP