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A hybrid framework for solving multi-objective scheduling problems

A hybrid framework for solving multi-objective scheduling problems
The proposed new technologies in the context of industry 4.0 challenge the current practices of scheduling in industry and their associated research in academia. The conventional optimization techniques that are employed for solving scheduling problems are either computationally expensive or lack the required quality. In addition, the majority the previous works addressed either a single objective or a weighted sum objective optimization measure. Therefore, we propose an adaptive scheduling framework to address hybrid flow shop scheduling problems considering multi-objective optimality measures. The framework is motivated by a hybrid design to combine the use of heuristic and metaheuristic approaches. The main idea behind the presented concept is to achieve an acceptable tradeoff between the quality of the suggested solutions for a problem and the required computational effort to obtain them. We relied on the Non-dominated Sorting Genetic Algorithms III (NSGA III) to design the control strategy and developed a set of allocation and sequencing heuristics. The obtained computational results are compared to pure metaheuristics for solving thirty problem instances that are obtained from a manufacturing environment in the field of printed circuit board assembly production. The preliminary computational results show that the framework fully dominates the metaheuristic for solving 86.6 % of the problem instances. The framework delivers a set of high-quality solutions for solving the problem in an average of 4.5 % fraction of the required computational time of the metaheuristic (2 minutes). Thus, it can be employed for addressing scheduling matters in manufacturing environments in real-time. In terms of perused objective measures, the approach delivers in average up to 21 % better results for minimizing four objective values than the metaheuristic as shown for instance in Figure 1.