Current Research

My Research Associate post is jointly funded by Cardiff School of Mathematics and Aneurin Bevan Health Board, so my work commitments are accordingly shared between the two organisations. Within the Health Board, I am part of the Aneurin Bevan Continuous Improvement Modelling Unit where my specific role involves projects which include:

Optimisation: determining the most efficient use of resources.
Scheduling: assigning workloads and tasks equitably and efficiently.
Statistics: supporting teams with the interpretation and presentation of data.

Previous Research

The work presented in my PhD thesis concerns the problem of dynamic vehicle routing. The motivation for this was the increasing demands on transportation services to deliver fast, efficient and reliable service meaning systems are now needed for dispatching transportation requests that arrive dynamically throughout the scheduling horizon.

The focus of the research was the dynamic pickup and delivery problem with time windows, where requests are not completely known in advance but become available during the scheduling horizon. All requests have to be satisfied by a given fleet of vehicles and each request has a pickup and delivery location, along with a time window at which services can take place. To solve the DPDPTW, our algorithm is embedded in a rolling horizon framework, thus allowing the problem to be viewed as a series of static sub-problems.

The research began by considering the static variant of the problem using both heuristic and metaheuristic methods. For the dynamic problem, investigations were performed to identify how requests arriving dynamically should be incorporated into the solution. Varying degrees of urgency and proportions of dynamic requests were examined. Further investigations looked at improving the solutions over time and identifying appropriate improvement heuristics.

This continually increasing area of research covers many real-life problems such as a health courier service. Here, the problem consists of the pickup and delivery of mail, specimens and equipment between hospitals, GP surgeries and health centres. Final research applied our findings to a real-life example of this problem, both for static schedules and a real-time 24/7 service.