Uncertainty in the Cloud: An Angel-Daemon Approach to Modelling Performance
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- Stewart A., Gabarro J., Keenan A. (2015) Uncertainty in the Cloud: An Angel-Daemon Approach to Modelling Performance. In: Destercke S., Denoeux T. (eds) Symbolic and Quantitative Approaches to Reasoning with Uncertainty. ECSQARU 2015. Lecture Notes in Computer Science, vol 9161. Springer, Cham
Uncertainty profiles are used to study the effects of contention within cloud and service-based environments. An uncertainty profile provides a qualitative description of an environment whose quality of service (QoS) may fluctuate unpredictably. Uncertain environments are modelled by strategic games with two agents; a daemon is used to represent overload and high resource contention; an angel is used to represent an idealised resource allocation situation with no underlying contention. Assessments of uncertainty profiles are useful in two ways: firstly, they provide a broad understanding of how environmental stress can effect an application’s performance (and reliability); secondly, they allow the effects of introducing redundancy into a computation to be assessed.