Locked in Syndrome

These paired activities, from Paul Curzon of the CS4FN team, offer an interesting slant on search algorithms and their relative efficiency.

Students are asked to consider sufferers of ‘locked-in syndrome’, a condition that leaves a healthy mind inside body that is, often, completely paralysed. If the sufferer can move one part of the body, for instance by blinking, then a way to give them a ‘voice’ can be found. This involves the use of search algorithms to choose from the alphabet one letter at a time; Professor Stephen Hawking uses a similar approach.

By linking this effort to a game of ’20 Questions’, the lesson shows that there are more efficient ways of selecting letters than by simply going through the whole alphabet. The author Jean-Dominique Bauby wrote his autobiography, ‘The Diving Bell and the Butterfly’, using such a system. It becomes clear that small improvements in the algorithm for selecting letters can mean big savings in time when they are repeatedly ‘run’, i.e. while writing a book. The result shows how ‘divide and conquer’ approaches to search are more efficient that binary search methods. It then extends the topic to look at indexes, and offers suggested ‘unplugged’ extension activities.

Detailed background information is contained within the ‘searching to speak’ accompanying document.

The activity would be useful from lower secondary through to A-Level computing and computer science.

Show health and safety information

Please be aware that resources have been published on the website in the form that they were originally supplied. This means that procedures reflect general practice and standards applicable at the time resources were produced and cannot be assumed to be acceptable today. Website users are fully responsible for ensuring that any activity, including practical work, which they carry out is in accordance with current regulations related to health and safety and that an appropriate risk assessment has been carried out.

Downloads

Published by

Actions

Share this resource

Lists that tag this content