## 2 Literature Review
Reference [22] developed a framework for the design of an integrated supermarket and feeding system for mixed-model assembly lines that included, in the second stage, the evaluation of the dynamic aspects of the problem. A case study based on an automotive production line was presented, and an analysis of the effects of the variability of fleet size, tow train capacity, and tow train loading interval was conducted. The most recent contributions that included the dynamic aspect within the parts feeding problem in mixed-model assembly lines focused on two main directions: (1) the scheduling problem of internal vehicles and (2) the development of multi-objective models that include the evaluation of energy consumption, which is part of a broader tendency towards the incorporation of sustainability within the productive sector [23]. Works that fall within the first research direction are: [24; 25; 26; 27]. For example, reference [25] investigated the dynamic scheduling of tow trains in an automotive assembly line, with the objective of minimizing the weighted sum of the assembly line throughput and the material delivery distance. A simulation model of the real assembly line was developed using Plant Simulation in order to generate training samples based on the system parameters configuration; reference [27] studied the dynamic parts feeding scheduling problem in an automotive mixed model assembly line under a Kanban-based parts feeding policy, considering also the dynamic disturbances of the assembly lines. The considered dynamic disturbances were: variations of the production mix, variations in the weights of the scheduling criteria, maintenance of AGVs, and short-term adjustment of the production sequence. Contributions that followed the second research direction are: [28; 29; 30]. For example, reference [30] aimed to improve the scheduling algorithm that governs mobile robots by including their energy consumption in the operational criteria, in order to optimize the overall energy efficiency and sustainability of the parts feeding system. Two other recent contributions did not follow the two mentioned directions but explored other themes: reference [31] studied the concept of line-integrated supermarkets combining station assignment and operator scheduling problems, including in their work the dynamic variability of the demand at the stations and the variability in the capacity of both bins and operators; reference [32] focused on an even more short-term decision level: the launch control of a new car model in a mixed-model assembly line under real-time conditions (which include variations of the processing times and setup costs). In conclusion, in the extant literature on parts feeding policies for mixed-model assembly lines, there are a few gaps that can be summarized as follows:  
* Few studies focused on the dynamic aspect of the parts feeding problem. * The studies that included dynamic elements, especially the most recent ones, focused almost exclusively on the scheduling problem of internal vehicles or on the development of multi-objective models that include energy consumption. * There are no studies on the station-sequence policy, despite its wide adoption in the industrial world. Considering these gaps, we can therefore state that, to the best of our knowledge, this paper represents the first work to perform a deep assessment of the station-sequence feeding policy, as well as being the first to study its dynamic time dependence and the evaluation of the impact of such dependence on the performance of the system.