Incorporating remanufacturing in a periodic review inventory system: Optimal and heuristic inventory control policies

   School of Mathematics and Physics

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  Dr C-K Sim  Applications accepted all year round  Self-Funded PhD Students Only

About the Project

Applications are invited for a self-funded, 3-year full-time or 6-year part time PhD project.

The PhD will be based in the School of Mathematics and Physics, and will be supervised by Dr Chee Khian Sim.

The work on this project could involve:

  • Designing an optimal inventory control policy on a periodic review inventory system that has remanufacturing capability.
  • Designing a heuristic inventory control policy on the system that can be implemented easily. 
  • Analysing the heuristic inventory control policy for its closeness to optimality.

Project description

This project is to study inventory control policies of a periodic review inventory system that has remanufacturing capability. It has the published work [1] by the project supervisor as its basis. It is a timely project on the active research area of environmental sustainability, as remanufacturing, an advanced form of recycling, is often considered an environmental preferable choice of end-of-life option.  

The novelty of this project is to model returned products, called cores, to the inventory system from past sales. Modelling cores from past sales is realistic and fills a gap in the literature which treats sales and demand as identical. We consider the demand faced by the system to be stochastic. Since demand is stochastic, dynamic programming methodology is appropriate to model the expected system cost. We wish to keep system cost as low as possible by designing appropriate inventory control policies, such as one that minimises this cost. To find a tractable optimal control policy, the challenge is to show that the dynamic program is a convex program. This can be achieved by appropriately modelling cores from past sales and manufacturing in the system. The insight gained in this process of finding the optimal policy allows us to design an easily implementable heuristic control policy that is provably close to minimising system cost.

The student will be supervised by Dr. Sim in the School of Mathematics and Physics. Dr. Sim has more than 10 years of experience working on optimal inventory management, with numerous papers in the area published in widely-read, international operational research journals. He has experience supervising graduate students, and is keen to work with students.  

[1] M. Chou, C.K. Sim & X.-M. Yuan, Policies for inventory models with product returns forecast from past demands and past sales, Annals of Operations Research, Vol. 288(2020), pp. 137-180.

General admissions criteria

You'll need a good first degree from an internationally recognised university or a Master’s degree in an appropriate subject. In exceptional cases, we may consider equivalent professional experience and/or qualifications. English language proficiency at a minimum of IELTS band 6.5 with no component score below 6.0.

Specific candidate requirements

A good first degree or MSc degree in Mathematics, Operational Research or Industrial/Manufacturing Engineering with a strong quantitative background. The candidate should be familiar with dynamic programming, the theory of convex optimisation, and have programming experience.

How to Apply

We encourage you to contact Dr Chee Khian Sim ([Email Address Removed]) to discuss your interest before you apply, quoting the project code.

When you are ready to apply, please follow the 'Apply now' link on the Operational Research and Logistics PhD subject area page and select the link for the relevant intake. Make sure you submit a personal statement, proof of your degrees and grades, details of two referees, proof of your English language proficiency and an up-to-date CV. Our ‘How to Apply’ page offers further guidance on the PhD application process. 

When applying please quote project code: SMAP7380423.

Engineering (12) Mathematics (25)

Funding Notes

Self-funded PhD students only.
PhD full-time and part-time courses are eligible for the UK Government Doctoral Loan (UK students only).
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