Showing 2 results for Reisi-Nafchi
S. M. Navabi, M. Reisi-Nafchi, Gh. Moslehi,
Volume 38, Issue 2 (2-2020)
Abstract
Nowadays, outpatient providers are struggling to reduce the current costs and improve the service quality. A part of the outpatient service provider is a hemodialysis department with expensive supplies and equipment. Therefore, in the present paper, the scheduling of hemodialysis patients with their preferences has been studied. The aim of scheduling hemodialysis patients in this study is to minimize the normalized weighted sum of deviations from the patients' preferences and the total completion time. It should be noted that the patient's preferences include beds, treatment combination of days and their turn. To solve the problem, two mathematical models have been presented. Performence of the models in solving the real data of the hemodyalisis department of Imam Khomeini Hospital, in Kermanshah, was investigated. The results showed the efficiency of the proposed models in considering the preferences of patients; however, these preferences in the hospital schedule were considered in few cases, as far as it was possible. So, these preferences has no priority in the hospital schedule. In addition to considering the patients’ preferences, the solution of models reduced the total completion time of the pationts treatment. Also, one of the proposed models in this papercould optimally solve the instances three times larger than the hospital cases
N. Fattahi, M. Reisi-Nafchi, G. Moslehi,
Volume 39, Issue 1 (8-2020)
Abstract
Scheduling in production environments is used as a competitive tool to improve efficiency and respond to customer requests. In this paper, a scheduling problem is investigated in a three-stage flexible flowshop environment with the consideration of blocking and batch processing. This problem has been inspired by the charging and packaging line of a large battery manufacturer. In this environment, the first and third stages involve a single processor machine, and the second one consists of m identical parallel batch processing machines. The objective is to minimize the total weighted tardiness of the received orders.Given the lack of consideration of this problem in the literature, first, a mathematical programming model is presented for the problem. Also, due to the NP-hardness of the problem, a variable neighborhood search algorithm and a memetic algorithm are developed to solve it. The computational results show that the variable neighborhood search algorithm can solve instances up to 1200 orders and 15 machines with an average deviation of about 1.9%, relative to the best solution of the two algorithms, and the memetic algorithm can solve instances up to 1200 orders and 15 machines with an average deviation of about 7.8%, as compared e to the best solution of the two algorithms. In general, computational results show the better performance of the variable neighborhood search algorithm in comparison to the memetic algorithm.
