arXiv subjects

Dag McGeorge

Publications and source records attributed to Dag McGeorge.

3 recordsLinked to original sources

arXiv2025

A modular risk concept for complex systems

This paper motivates the views that for complex systems, risk should be controlled by enforcing constraints in a modular way at different system levels, that the constraints can be expressed as assurance contracts and that acceptable risk mitigation can be demonstrated in assurance case modules. This short paper explains how already existing methodologies can be combined to create a concept for modular risk assessment. The main novelty is the use of so-called contract-based design (CBD) contracts and refinements as risk constraints. This idea is presented here with the objective of receiving feedback from industry and academia.

cs.LO↗

arXiv2024

Modular assurance of an Autonomous Ferry using Contract-Based Design and Simulation-based Verification Principles

With the introduction of autonomous technology into our society, e.g. autonomous shipping, it is important to assess and assure the safety of autonomous systems in a real-world context. Simulation-based testing is a common approach to attempt to verify performance of autonomous systems, but assurance also requires formal evidence. This paper introduces the Assurance of Digital Assets (ADA) framework, a structured method for the assurance of digital assets, i.e. novel, complex, or intelligent systems enabled by digital technologies, using contract-based design. Results are shown for an autonomous ferry assurance case, focusing on collision avoidance during the ferry's transit. Further, we discuss the role of simulation-based testing in verifying compliance to contract specifications, to build the necessary evidence for an assurance case.

cs.LO↗

arXiv2024

Modular Assurance of Complex Systems Using Contract-Based Design Principles

A growing number of safety-critical industries agree that building confidence in complex systems can be achieved through evidence and structured argumentation framed in assurance cases. Nevertheless, according to practical industry experience, assurance cases can easily become too rigorous and difficult to develop and maintain when applied to complex systems. Therefore, we propose to use contract-based development (CBD), a method to manage complexity originally developed in computer science, to simplify assurance cases by modularizing them. This paper will not only summarize relevant previous work such as constructing consistent modular assurance cases using CBD, but more importantly also propose a novel approach to integrate CBD with the argumentation in assurance case modules. This approach will allow subject-matter and domain experts to build assurance case modules together without having to know CBD. This can help a broader application of these methods in industry because subject matter experts outside of computer science can contribute to cross disciplinary co-development of assurance cases without having to learn CBD. Industry experience has proven four rules of thumb helpful for developing high-quality assurance cases. This article illustrates their usefulness and explains how modular assurance enables assurance that accounts for the interdependency of different concerns such as safety, security and performance.

cs.LO↗