Browsing by Author "Savery, Cheryl"

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    The human factors of consistency maintenance in multiplayer computer games
    (ACM, 2010) Savery, Cheryl; Graham, T.C. Nicholas; Gutwin, Carl
    Consistency maintenance (CM) techniques are a crucial part of many distributed systems, and are particularly important in networked games. In this paper we describe a framework of the human factors of CM, to help designers of networked games make better decisions about its use. The framework shows that there is wide variance in the CM requirements of different game situations, identifies the types of requirements that can be considered, and analyses the effects of several consistency schemes on user experience factors. To further explore these issues, we carried out a simulation study that compared four CM algorithms. The experiment confirms many of the predictions of the framework, and reveals additional subtleties of the algorithms. Our work is the first to look comprehensively at the tradeoffs and costs of CM, and our results are a strong starting point that will help designers improve on the user's quality of experience in distributed shared environments.
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    It's about time: confronting latency in the development of groupware systems
    (ACM, 2011) Savery, Cheryl; Graham, T.C. Nicholas
    The presence of network latency leads to usability problems in distributed groupware applications. Example problems include difficulty synchronizing tightly-coupled collaboration, jarring changes in the user interface following the repair of conflicting operations, and confusion when participants discuss state that appears differently to each of them. Techniques exist that can help mitigate the effects of latency, both in the user interface and the groupware application. However, as these techniques necessitate the manipulation of state over time, the effort required to implement them can be significant. In this paper, we present timelines, a programming model allowing the explicit treatment of time in groupware applications. The model has been implemented as part of the Janus toolkit.
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    What + when = how: The timelines approach to consistency in networked games
    (IEEE, 2011) Savery, Cheryl; Graham, T.C. Nicholas
    Consistency maintenance techniques used in networked multiplayer games require a tradeoff between the degree of consistency and the responsiveness to player commands. The choice of which technique is most appropriate depends upon the specific game situation. However, all techniques share the need to deal with time as well as with game state data. This can make implementing consistency maintenance techniques difficult. The solution is to have a programming model that is better able to deal with time. In this paper, we present such a programming model, timelines. Timelines allow for the explicit treatment of time and have been implemented as part of the Janus toolkit.
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    When Paper Meets Multi-Touch: A Study of Multi-Modal Interactions in Air Traffic Control
    (Springer, 2013) Savery, Cheryl; Hurter, Christophe; Lesbordes, Remi; Cordeil, Maxime; Graham, T.C. Nicholas
    For expert interfaces, it is not obvious whether providing multiple modes of interaction, each tuned to different sub-tasks, leads to a better user experience than providing a more limited set. In this paper, we investigate this question in the context of air traffic control. We present and analyze an augmented flight strip board offering several forms of interaction, including touch, digital pen and physical paper objects. We explore the technical challenges of adding finger detection to such a flight strip board and evaluate how expert air traffic controllers interact with the resulting system. We find that users are able to quickly adapt to the wide range of offered modalities. Users were not overburden by the choice of different modalities, and did not find it difficult to determine the appropriate modality to use for each interaction.