An STPA-based formal composition framework for trustworthy autonomous maritime systems
An STPA-based formal composition framework for trustworthy autonomous maritime systems
A key risk with autonomous systems (AS) is the trustworthiness of the decision-making and control mechanisms that replace human control. To be trustworthy, systems need to remain safe while being resilient to unpredictable changes, functional/operational failures and cybersecurity threats. Rigorous validation and verification are essential to ensure trustworthiness of AS. Current engineering practice relies heavily on Verification and Validation (V&V) test-and-fix of system characteristics which is very time-consuming and expensive, limiting the possibilities for exploration of alternatives in system design. Instead, we focus on building a correct-by-construction system. In this paper, we present an approach to identifying and analysing mission requirements for squads of autonomous missions. Clear definition of requirements is an important pre-requisite for mission planning and for V&V of mission management. We use a structured approach to requirements identification and use formal modelling to help remove ambiguities in the requirements and to specify formal properties that should be satisfied by the missions. Our approach use a combination of analysis techniques based on Systems Theoretic Process Analysis (STPA) and formal modelling to generate critical requirements that ensure the safety and security of the system. We also suggest a compositional approach for formal modelling to enhance re-usability and address the complexity of formal modelling. Our approach is being evaluated through consideration of a combined mission of an Unmanned Surface Vehicle (USV) with deployment/recovery of small Unmanned Underwater Vehicles (UUV) within a shipping channel whereby the USV has to safely maintain station for a long period and then proceed to recover the UUV, while maintaining a communication link to an Unmanned Aerial Vehicle (UAV).
Event-B, Formal Methods, Maritime Autonomous Systems, Requirements, SE-STPA, STPA
Dghaym, Dana
b7b69fe2-c9ff-43ad-a6ba-8b41d6fd19fc
Hoang, Thai Son
dcc0431d-2847-4e1d-9a85-54e4d6bab43f
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Butler, Michael
54b9c2c7-2574-438e-9a36-6842a3d53ed0
Downes, Jon
ebc0f09b-9d33-4815-bedf-bc77df59c822
Pritchard, Ben
7829a095-d97d-488c-852c-02c23f939429
April 2021
Dghaym, Dana
b7b69fe2-c9ff-43ad-a6ba-8b41d6fd19fc
Hoang, Thai Son
dcc0431d-2847-4e1d-9a85-54e4d6bab43f
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Butler, Michael
54b9c2c7-2574-438e-9a36-6842a3d53ed0
Downes, Jon
ebc0f09b-9d33-4815-bedf-bc77df59c822
Pritchard, Ben
7829a095-d97d-488c-852c-02c23f939429
Dghaym, Dana, Hoang, Thai Son, Turnock, Stephen, Butler, Michael, Downes, Jon and Pritchard, Ben
(2021)
An STPA-based formal composition framework for trustworthy autonomous maritime systems.
Safety Science, 136 (0925-7535), [105139].
(doi:10.1016/j.ssci.2020.105139).
Abstract
A key risk with autonomous systems (AS) is the trustworthiness of the decision-making and control mechanisms that replace human control. To be trustworthy, systems need to remain safe while being resilient to unpredictable changes, functional/operational failures and cybersecurity threats. Rigorous validation and verification are essential to ensure trustworthiness of AS. Current engineering practice relies heavily on Verification and Validation (V&V) test-and-fix of system characteristics which is very time-consuming and expensive, limiting the possibilities for exploration of alternatives in system design. Instead, we focus on building a correct-by-construction system. In this paper, we present an approach to identifying and analysing mission requirements for squads of autonomous missions. Clear definition of requirements is an important pre-requisite for mission planning and for V&V of mission management. We use a structured approach to requirements identification and use formal modelling to help remove ambiguities in the requirements and to specify formal properties that should be satisfied by the missions. Our approach use a combination of analysis techniques based on Systems Theoretic Process Analysis (STPA) and formal modelling to generate critical requirements that ensure the safety and security of the system. We also suggest a compositional approach for formal modelling to enhance re-usability and address the complexity of formal modelling. Our approach is being evaluated through consideration of a combined mission of an Unmanned Surface Vehicle (USV) with deployment/recovery of small Unmanned Underwater Vehicles (UUV) within a shipping channel whereby the USV has to safely maintain station for a long period and then proceed to recover the UUV, while maintaining a communication link to an Unmanned Aerial Vehicle (UAV).
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Accepted/In Press date: 18 December 2020
Published date: April 2021
Additional Information:
Funding Information:
This research was undertaken as part of the on-going strategic partnership between Thales and University of Southampton under which the IMMS 2019 Project was funded. Supporting material for this study is openly available from the University of Southampton repository at.
Funding Information:
This research was undertaken as part of the on-going strategic partnership between Thales and University of Southampton under which the IMMS 2019 Project was funded.
Publisher Copyright:
© 2021 Elsevier Ltd
Keywords:
Event-B, Formal Methods, Maritime Autonomous Systems, Requirements, SE-STPA, STPA
Identifiers
Local EPrints ID: 445847
URI: http://eprints.soton.ac.uk/id/eprint/445847
ISSN: 0925-7535
PURE UUID: a508da8f-075a-4eb3-a38c-4272e105928e
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Date deposited: 11 Jan 2021 17:31
Last modified: 30 Oct 2023 03:11
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