May 2015

Tom Rodden, On lions, impala, and bigraphs: modelling interactions in Ubiquitous Computing.

On lions, impala, and bigraphs: modelling interactions in Ubiquitous Computing.


As ubiquitous systems have moved out of the lab and into the world the need to think more systematically about how there are realised has grown. This talk will present intradisciplinary work I have been engaged in with other computing colleagues on how we might develop more formal models and understanding of ubiquitous computing systems. The formal modelling of computing systems has proved valuable in areas as diverse as reliability, security and robustness. However, the emergence of ubiquitous computing raises new challenges for formal modelling due to their contextual nature and dependence on unreliable sensing systems. In this work we undertook an exploration of modelling an example ubiquitous system called the Savannah game using the approach of bigraphical rewriting systems.


This required an unusual intra-disciplinary dialogue between formal computing and human- computer interaction researchers to model systematically four perspectives on Savannah: computational, physical, human and technical. Each perspective in turn drew upon a range of different modelling traditions. For example, the human perspective built upon previous work on proxemics, which uses physical distance as a means to understand interaction.


In this talk I hope to show how our model explains observed inconsistencies in Savannah and ex- tend it to resolve these. I will then reflect on the need for intradisciplinary work of this form and the importance of the bigraph diagrammatic form to support this form of engagement.


Tom Rodden ( is a Professor of Interactive Computing at the University of Nottingham. His research brings together a range of human and technical disciplines, technologies and techniques to tackle the human, social, ethical and technical challenges involved in ubiquitous computing and the increasing used of personal data. He leads the Mixed Reality Laboratory ( an interdisciplinary research facility that is home of a team of over 40 researchers. He founded and currently co-directs the Horizon Digital Economy Research Institute (, a university wide interdisciplinary research centre focusing on ethical use of our growing digital footprint. He has previously directed the EPSRC Equator IRC ( a national interdisciplinary research collaboration exploring the place of digital interaction in our everyday world. He is a fellow of the British Computer Society and the ACM and was elected to the ACM SIGCHI Academy in 2009 (