Ocular Prosthesis Fabrication Scheduling Using Genetic Algorithm

Abstract

This research examines an ocular prosthesis centre’s operation and incorporates scheduling decision techniques to optimise its fabrication. A customised eye prosthesis is a make-to-order product which involves several labour-intensive processes and inherently poses scheduling challenges. As a result, patients' fitment dates are appointed with extra time to account for potential delays. The objective of scheduling is to minimise both total completion time and tardiness. The methodology begins with a process review of the customised eye prosthesis fabrication and criteria. Subsequently, a Mixed Integer Linear Programming (MILP) model is formulated to solve the assignment and sequencing problems. It is found during this stage that computational time increases significantly as the number of orders increases. To solve this problem, a Genetic Algorithm (GA) is proposed to find a near-optimal solution in a reasonable computational time. Instances selected for experiment are based on characteristics of a tertiary hospital’s ocular prosthesis centre. Small instances are experimented to validate the proposed algorithm against the MILP model. The GA demonstrates near-optimal solutions with a variance of one percent, with reasonable computational time. Practical-size problems are subsequently solved using the proposed algorithm. In conclusion, the proposed GA yields satisfactory solutions with acceptable runtime for this application.