On lions, impala, and bigraphs: modelling interactions in physical/virtual spaces

Benford, S., Calder, M. , Rodden, T. and Sevegnani, M. (2016) On lions, impala, and bigraphs: modelling interactions in physical/virtual spaces. ACM Transactions on Computer-Human Interaction, 23(2), 9. (doi: 10.1145/2882784)

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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. We present an exploration of modelling an example ubiquitous system called the Savannah game using bigraphs, which are based on a universal process algebra that encapsulates both dynamic and spatial behaviour of autonomous agents that interact and move among each other, or within each other. This required an unusual intra-disciplinary dialogue between Formal Computing and Human-Computer Interaction researchers to model systematically four perspectives on social and system behaviour in Savannah: computational, physical, human and technical. It also required extending bigraphs with bigraphical patterns and probabilistic transitions. We develop a model of the four perspectives, focussing on the contribution of formality to the challenges of designing and implementing mixed reality systems, rather than on the details of the formalism itself. We develop the models through examples, using the graphical representation of bigraphs, rather than the algebraic form. We show how our model explains observed inconsistencies in user trials of Savannah, and then how formal analysis reveals an incompleteness in design and guides extensions of the model and/or possible system re-design to resolve this. We reflect on how we might model more complex ubiquitous systems in the future and the importance of the bigraph diagrammatic form in enabling Formal Computing to engage with other disciplines.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Sevegnani, Dr Michele and Calder, Professor Muffy
Authors: Benford, S., Calder, M., Rodden, T., and Sevegnani, M.
College/School:College of Science and Engineering > School of Computing Science
Journal Name:ACM Transactions on Computer-Human Interaction
Publisher:ACM Press
ISSN (Online):1557-7325
Copyright Holders:Copyright © 2016 ACM
First Published:First published in ACM Transactions on Computer-Human Interaction 23(2): 9
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
443471Verifying interoperability requirements in Pervasive Systems (VPS)Muffy CalderEngineering & Physical Sciences Research Council (EPSRC)EP/F033206/1COM - COMPUTING SCIENCE