Systems complexity jeopardising safety
One example of the work being undertaken is a PhD thesis which looked at cyber-physical systems safety but from a wider perspective and considered how the growing complexity of systems could present new challenges, leading to unpredictable system behaviour and thus jeopardising safety. The subjects chosen for this work were the diesel-electric propulsion system and the power plant alternatives of a modern cruise ship, as well as an open loop exhaust gas scrubber system.
Using a range of scientific analytical tools, a detailed Fault Tree was developed that captures the effects of both the physical components/subsystems and the software functions’ failures. The study demonstrated that the developed method led to the prediction of the top system events failure rates and provided a more detailed and complete Fault Tree compared to previous studies. It also demonstrated that the increase of the propulsion system reliability/availability does not always result in the system blackout frequency reduction. Potentially, this new safety analysis method could be integrated with sensor measurements to provide pre-warning of possible failures to the ship’s crew.
The thesis includes a chapter on ‘automated blackout monitoring system development’, which resulted in third prize being awarded to the PhD student Victor Bolbot in the prestigious TRA Visions 2020 Young Researcher Competition.
Prof. Theotokatos says research work in this area is important as it responds to the industry demands. “It also gives us the tools and scientific methods to address the safety of modern, next-generation cyber-physical systems, which are obviously the future of the industry, and will lead to the development of autonomous vessels,” says Prof. Theotokatos.
Cyber-physical systems safety study
One of the research papers published earlier this year as an outcome of the preceding PhD thesis, – “A novel method for safety analysis of cyber-physical systems – application to a ship exhaust gas scrubber system” – has particular resonance in the early days of the IMO’s new SOx restrictions. This study describes the methodology developed for the safety analysis of complex cyber-physical systems, focusing on the case study of an open-loop scrubber system. This paper was published jointly by the MSRC and DNV.
Although an open-loop scrubber was chosen for this investigation, the formulated methodology can also be applied to other complex systems. It is expected that the proposed methodology will constitute a valuable tool for safety analysis during the initial design phases and support safe systems operation.
Developing modern safety assessment methods
The research work has also resulted in the MSRC participating in the EU-funded AUTOSHIP project aimed at building and testing two full-scale autonomous vessels. “Our work in this project will focus on modern safety assessment, to identify the gaps and provide improvements in the existing framework and employed methods. We believe our contribution will further drive the development of the MSRC as autonomous ships will continue to be in the spotlight in the years ahead,” adds Prof. Theotokatos.
Looking ahead, Prof. Theotokatos has a vision to further expand the MSRC, rendering it an internationally recognised centre. “We have a long-term vision, and in order to accomplish it, we will try to make the best use of the sponsors funds to build up efficient teams and deliver results – and this is what we’ve demonstrated so far. Certainly, relationships with sponsors like DNV have greatly assisted us in gaining a certain status and now it’s up to us to continue working towards the sustainability of the MSRC.”
Prof. Theotokatos believes the maritime industry and society at large face “immense challenges that need to be addressed, and our aim as academics and researchers working with industry is to manage and contain those challenges. We need to get to the point where there are zero accidents, zero emissions, zero pollution, and make the industry more sustainable in order to meet stakeholders’ and society’s expectations. More collaboration, research and innovation will be important and that’s core to the MSRC’s strategy and research activities,” he concluded.