Part III Physics projects (2001)

Dr. David J.C. MacKay, Astrophysics group

Room 961 Rutherford building, x39852,


Meet to discuss at 2pm on Tuesday October 16th

1. Why do you weigh more, according to your bathroom weighing machine, when it is sitting on thick carpet? (Experimental/Theoretical)

To a theoretical physicist, the idea is absurd, but ask anyone who thinks they have a weight problem, and they will know it's true: you have to put the weighing machine on a hard floor, otherwise you'll appear to weigh more.

In this project you will design and carry out experiments on weighing machines to quantify this phenomenon, and work out a theory for it.

It is expected that a journal paper will result from the completed research project.


2. Language modelling (Computational)

Probabilistic language models are essential both for efficient text compression and for efficient text entry to computers (by speech recognition, for example). The quality of a language model can be quantified by how well it compresses a test file. While state-of-the-art text compressors achieve compression down to about 2 bits per character, it is believed that the entropy of English text is as small as 1 bit per character.

In this project you will survey existing character-based and word-based language models used in text compression and speech recognition, then develop and test new language models.

Further reading:
a. A Hierarchical Dirichlet Language Model (MacKay and Peto)
b. Dasher - a Data Entry Interface Using Continuous Gestures and Language Models (Ward, Blackwell, and MacKay)


David MacKay <>
Last modified: Fri Oct 5 11:28:10 2001