Mathematical Optimization Models
Fatemeh nikkhoo; Ali Husseinzadeh Kashan; ehsan nikbakhsh; bakhtiar ostadi
Abstract
Purpose: The order picking problem is very important as one of the logistics activities of the warehouse. This problem is defined as collecting orders from different warehouse locations to respond to customers' orders in the shortest possible time. The purpose of this paper is to provide a multi-objective ...
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Purpose: The order picking problem is very important as one of the logistics activities of the warehouse. This problem is defined as collecting orders from different warehouse locations to respond to customers' orders in the shortest possible time. The purpose of this paper is to provide a multi-objective mathematical programming model for integrating the decisions of batching, routing, scheduling of pickers with the problem of packaging in multi-warehouse environment. The objective functions include minimization of the delivery times and total order picking costs.
Methodology: In this research, first by reviewing the literature in the field of order picking, the research gaps of the problem have been identified. Then, taking into account the main constraints of the problem, a multi-objective mathematical model has been formulated for the multi-warehouse order picking problem. To solve the problem, the classic Benders decomposition algorithm and the accelerated Benders decomposition algorithm have been used. To validate and applicability of the proposed model, the data related to the warehouses of a company producing sanitary products in Iran was used as a case study and its results were reported in the article.
Findings: The results of the proposed model indicate that CPLEX is able to solve these problems up to small sizes in an acceptable time. Also, the numerical results show the performance of the Benders decomposition algorithm and the accelerated Benders algorithm as suitable alternatives for solving the model in the large-sized problems. The calculation results obtained from the implementation of the solution methods for the proposed model showed that in terms of the number of iterations and the calculation time, the accelerated Benders algorithm had better results than the classic Benders algorithm.
Originality/Value: In this research, for the first time, the order picking problem with considerations of the integrity of operational decisions has been formulated in the form of a multi-objective mathematical model for a multi-warehouse environment. In this article regarding the solution method, exact solution approaches have been used for the first time considering the structure of the problem. The computation results show that the proposed algorithms are efficient and suitable methods for problem solving.