1. Power and Propulsion Sciences Group, Cranfield University, Cranfield MK43 0AL, UK
2. Engineering Design Centre, Cambridge University, Trumpington Street, Cambridge CB2 1PZ, UK
3. Western Power Distribution Innovation, Pegasus Business Park, Derby DE74 2TU, UK
4. Complex System Research Centre, Cranfield School of Management, Cranfield MK43 0AL, UK