Attaining flexibility in seru production system by means of Shojinka: An optimization model and solution approaches

Abstract This study explores the problem of workforce scheduling in the seru production environment where operations are performed within independent serus, so-called assembly cells. Although the seru system attracts more attention in recent years, the addressed problem remains scarcely investigated in the existing literature. To analyze the problem in detail, first, a comprehensive optimization model is proposed by placing an emphasis on achieving Shojinka, which is a Japanese word. Subsequently, the structural properties, the lower and upper bounds are presented to aid the understanding of the problem. The model is solved optimally for small-sized problems; however, several algorithms with two different initial population generation procedures are developed for large-sized problems due to the complexity of the problem. The impact of achieving Shojinka along with the workers’ heterogeneity is investigated in detail through experimental design. To this end, four different scenarios are constructed and a distinct algorithm is devoted to each scenario for the comparison purpose. According to the results, allowing interseru worker transfer leads to a considerable decrease in the makespan. This study contributes to the existing academic literature by presenting several insights regarding the implementation of operational strategies on the seru production system.