Page 63 - programme book

OR-004
Simulated Annealing Approach for an Outpatient Scheduling in a
Hemodialysis Unit

a)
d)
b)
c)
Ashweena Sundar , Nor Aliza Abdul Rahmin , Chen Chuei Yee and Nazihah Md.Ali
Department of Mathematics and Statistics, Faculty of Science,
University of Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.

a) ashweenasundar@gmail.com
b) Corresponding author: aliza@upm.edu.my
c) cychen@upm.edu.my
d) nazihah@upm.edu.my

Abstract. National Renal Registry (NRR) Malaysia has reported that the demand for dialysis treatment
among chronic kidney disease (CKD) and end-stage kidney disease (ESKD) patients rises every year.
However, available hemodialysis units have limited facilities to meet the current increasing demand.
This leads to congestion, long waiting times and an increase in the duration of stay (DOS) among
hemodialysis patients during their treatment sessions. Nurse assignments need to consider as well, as
the dialysis facilities must provide their best treatment plan. Therefore, in our research, we focus on
outpatient scheduling and nurse assignment problems in the hemodialysis unit. The objective is to
minimize patients’ total DOS, including the waiting time before and after the dialysis treatment. As
the optimization model consumes a high computational time to solve for a large-scale instance by
using the exact method, a simple heuristic is developed to deal with the problem. Later, the quality of
the solution is improved by using Simulated Annealing algorithm and backtracking heuristics is
applied for nurse assignment problems as at least two nurses are needed for each dialysis patient. The
results show that the solutions obtained for outpatient scheduling by the Simulated Annealing are of
good quality and has significantly reduced the computational time compare with the simple heuristic
even when considering more patients on the waiting list. As for total DOS, we have managed to obtain
the optimum value compared to the average DOS values for both 3-hour and 4-hour sessions.

Keywords: Outpatient Scheduling, Nurse Assignment, Simple Heuristic, Simulated Annealing,
Optimization