Safety-Critical Adaptation in Self-Adaptive Systems

TL;DR

This paper defines safety-critical self-adaptive systems, proposes a taxonomy for classifying adaptation types based on safety impact, and illustrates the approach with a water heating system example.

Contribution

It introduces a formal taxonomy for safety-related adaptation types and specifies safety case criteria for each, advancing safety assurance in self-adaptive systems.

Findings

Taxonomy categorizes adaptation types by safety impact

Safety case criteria vary with adaptation type

Water heating system example illustrates taxonomy application

Abstract

Modern systems are designed to operate in increasingly variable and uncertain environments. Not only are these environments complex, in the sense that they contain a tremendous number of variables, but they also change over time. Systems must be able to adjust their behaviour at run-time to manage these uncertainties. These self-adaptive systems have been studied extensively. This paper proposes a definition of a safety-critical self-adaptive system and then describes a taxonomy for classifying adaptations into different types based on their impact on the system's safety and the system's safety case. The taxonomy expresses criteria for classification and then describes specific criteria that the safety case for a self-adaptive system must satisfy, depending on the type of adaptations performed. Each type in the taxonomy is illustrated using the example of a safety-critical self-adaptive water heating system.