Keeping the Routes Open: Optimal Maintenance of Infrastructure Networks.

The maintenance and repair of large-scale transportation infrastructure is known to be very costly, as is the loss of efficiency and capacity when components of such infrastructure has been damaged. It is therefore of interest to allocate resources optimally to maintain such infrastructure. Specifically, given that the infrastructure is in some given state of repair or disrepair, with certain routes operating well and other routes damaged and not fit for use, we want to select or prioritise certain routes for repair so as to allocate resources as efficiently as possible.

These decisions must also be made sequentially: every time a new route is known to have been damaged, or an ongoing repair has been completed, we want to make a new decision on what to do next.

Generic algorithms already exist which learn to control these sequential decision-making problems optimally. For our problem, optimal control would mean that we minimise the average combined cost of ongoing repairs and loss of capacity over a long period of time. However, for complicated problems such as ours, these algorithms are known to be extremely slow and are therefore unsuitable, so we must turn our attention to more approximate or heuristic (rule-of-thumb) techniques.

Such techniques can explicitly incorporate any theoretical understanding of the problem, allowing optimal approaches to be learned much faster by exploiting any known properties. It is the creation and evaluation of such techniques, and the discovery or proof of theoretical properties, that is the focus of our research.

Our hope is that by finding suitable approximations or heuristics, these could be rolled out and applied to any network-based infrastructure, and yield results that outperform any simple naive approaches. In partnership with Naval Postgraduate School.