Stochastic game analysis and latency awareness for proactive self-adaptation

Abstract

Although different approaches to decision-making in selfadaptive systems have shown their effectiveness in the past by factoring in predictions about the system and its environment (e.g., resource availability), no proposal considers the latency associated with the execution of tactics upon the target system. However, different adaptation tactics can take different amounts of time until their effects can be observed. In reactive adaptation, ignoring adaptation tactic latency can lead to suboptimal adaptation decisions (e.g., activating a server that takes more time to boot than the transient spike in traffic that triggered its activation). In proactive adaptation, taking adaptation latency into account is necessary to get the system into the desired state to deal with an upcoming situation. In this paper, we introduce a formal analysis technique based on model checking of stochastic multiplayer games (SMGs) that enables us to quantify the potential benefits of employing different types of algorithms for self-adaptation. In particular, we apply this technique to show the potential benefit of considering adaptation tactic latency in proactive adaptation algorithms. Our results show that factoring in tactic latency in decision making improves the outcome of adaptation. We also present an algorithm to do proactive adaptation that considers tactic latency, and show that it achieves higher utility than an algorithm that under the assumption of no latency is optimal.

PRISM-games: verification and strategy synthesis for stochastic multi-player games with multiple objectives

“…Self-adaptive software architectures [10,26] Self-adaptive software automatically adapts its structure and behaviour according to changing requirements and quantitative goals. Several self-adaptive software architectures, such as adaptive industrial middleware used to monitor and manage sensor networks in renewable energy production plants, have been modelled as stochastic games and analysed.…”

Zone-based formal specification and timing analysis of real-time self-adaptive systems

“…In [68], Cámara et al presents a formal verification approach at design-time based on model checking of stochastic multiplayer games (SMGs) in which adaptation latency is considered explicitly -proactive latency-aware adaptation. In [69], the approach is also brought to run-time and takes into account the inherent uncertainty of the environment predictions needed for looking ahead.…”

An Iterative Decision-Making Scheme for Markov Decision Processes and Its Application to Self-adaptive Systems

“…Rainbow [9] supports the computation of cumulative costs and/or rewards when the likelihood parameters in the adaptation strategies are explicitly specified. Subsequent work [5,6] employs a combination of a simulation method and probabilistic model checking to evaluate properties such as resilience and adaptation latency. As mentioned, our IDMS can be economically embedded into Rainbow and extend the adaptation function of the latter.…”