Synthesizing structural and behavioral control for reconfigurations in component-based systems

Abstract

Abstract. Correctness of the behavior of an adaptive system during dynamic adaptation is an important challenge to realize correct adaptive systems. Dynamic adaptation refers to changes to both the functionality of the computational entities that comprise a composite system, as well as the structure of their interconnections, in response to variations in the environment, e.g., the load of requests on a server system. In this research, we view the problem of correct structural adaptation as a supervisory control problem and synthesize a reconfiguration controller that guides the behavior of a system during adaptation. The reconfiguration controller observes the system behavior during an adaptation and controls the system behavior by allowing/disallowing actions in a way to ensure that a given property is satisfied and a deadlock is avoided. The system during adaptation is modeled using a graph transition system and properties to be enforced are specified using a graph automaton. We adapt a classical theory of supervisory control for synthesizing a controller for controlling the behavior of a system modeled using graph transition systems. This theory is used to synthesize a controller that can impose both behavioral and structural constraints on the system during an adaptation. We apply a tool that we have implemented to support our approach on a case study involving https servers.

Assured Mission Adaptation of UAVs

“…Synthesis has also been used at development time to produce glue code, adapters and mediators (e.g., [6,44,50,73]). Its use at runtime has also been explored to support structural reconfiguration of systems (e.g., [4,56,82,83]).…”

“…The need for supporting arbitrary specification changes and update requirements that constrain the transition between specifications has been subject of more recent studies (e.g., [47,77,96]). Although they focus on specification and verification of update strategies, more recently work focuses on automated synthesis of update plans (e.g., [11,56,69,71,86]).…”

Engineering Trustworthy Self-Adaptive Software with Dynamic Assurance Cases

“…Formal proof was also used to provide evidence for properties of automatically synthesised controllers, e.g. the completeness and soundness of synthesised behavioral models that satisfy an expressive subset of liveness properties [40] and correctness and deadlock free adaptations performed by automatically synthesised controllers [70]. Finally, formal proof was used to demonstrate the correctness of adaptation effects, e.g.…”

Towards Secure Architecture-Based Adaptations

“…When a system needs to adapt because its goals may be jeopardized, several adaptations might be triggered [7], [9], [19], [27] and the system should choose and enforce one of the triggered adaptations to achieve its goals according to the business policies and preferences [12]. In addition, an adaptation can consist of several steps that are often not performed at once and the system may go through several transient configurations until it reaches the final configuration [10], [17], [18]. Consequently security has to be taken into account both during and in the resulting configuration of the adaptation process to be able to ensure a secure adaptation.…”