Debugging Logic and Search

Research areas

Temporary Supervisor

Professor John Slaney


This is a potential PhD project in the area where AI, programming and HCI overlap. Parts of it (negotiable) could be undertaken at Honours or Masters level. The project concerns debugging in the context of a constraint programming system. A user encodes a problem by modelling, which means writing a description of it in a logic-like language, and then the system evaluates the model by using some kind of solvers. Sometimes the logical model is incorrect, or it makes the solvers run in an inefficient way, so we need tools to help the user to correct or improve it. A first implementation of a kind of debugger for this was written a few years ago (see background reading) but there is a lot of research to be done to make a better one. We need to study what users actually do when debugging, to understand what information they need, and imagine new ways of using visualisation or other tools to provide them with that information. The concept of "debugging" here is quite new, since it is all about models and search, rather than programs and execution. This kind of debugging needs to be related to other user interactions with the software, including constraint acquisition, explanation generation and "what if" reasoning.


Develop new theoretical understanding and practical techniques for correctness and performance debugging of logical models. These need to be implemented, refined through experiments and brought to the point where they can be incorporated - for instance, in NICTA's new optimisation platform and in the logic teaching tool L4F at the ANU.


The student undertaking this project should have interests and skills in at least some of the following: applied logic, constraint satisfaction, HCI, visualisation. An ability to think "outside the box" is more important than deep technical knowledge, as there is a need for imaginative approaches and new concepts if we are to meet the challenges in this area. Some programming ability is also useful.

Background Literature

Andreas Bauer, Viorica Botea, Mark Brown, Matt Gray, DanielHarabor and John Slaney. An integrated modelling, debugging and visualisation environment for G12. In Proceedings of the 16th International Conference on Principles and Practice of Constraint Programming (CP-2010), 2010: 522-536.

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