Dr. Tristan Henderson has been a Lecturer in Computer Science in the University of St Andrews since December 2006 and is now a senior lecturer. In 2011 he helped cofound SACHI and his research revolves around measuring communications networks and their users. His PhD looked at measuring networked game servers and game players, but more recently he has been investigating new methodologies for measuring mobile, wireless and online social networks and their users. He attempts to use the results of this network measurement to build more usable networks. Specifically networks which support the functionality that users desire. For instance we can use network measurement to improve security and privacy so that people can use pervasive sensor networks. Or we can measure network behaviour and use this to inform the design of future networks. He is one of the Workshop Organisers for Health, Wealth and Identity Theft: Designing and evaluating usable security and privacy mechanisms for online happiness a Workshop at the British HCI 2011 conference, and organised the Privacy and Usability Methods Pow-wow at British HCI 2010.