A Lagrangian heuristic for task scheduling in cloud manufacturing considering the interests of different stakeholders
摘要
In the era of Industry 4.0, cloud manufacturing (CMfg) systems face the challenge of processing massive service requests under real-time constraints. Task scheduling plays a critical role in enhancing the overall profitability and responsiveness of such systems. This study investigates a complex task scheduling problem considering the conflicting interests of three key stakeholders: (1) customers (meeting demands), (2) suppliers (maximizing subtask allocation), and (3) the cloud provider (optimizing profit). We developed a mixed-integer programming model to satisfy these objectives simultaneously. Given the NP-hard nature and the high computational complexity of the problem on large-scale instances, traditional exact methods are insufficient for real-time applications. To address this, we propose two scalable algorithms: a Heuristic based on Lagrangian relaxation (HLR) and a three-phase loop heuristic (H3PL). The performance of these methods was rigorously evaluated against CPLEX, as well as state-of-the-art metaheuristics including genetic algorithm (GA) and simulated annealing (SA). The results indicate that HLR offers superior solution quality, achieving a gap of at most 7.98% from the optimum while reducing computation time by 79%, outperforming GA and SA in terms of convergence stability. Conversely, the H3PL algorithm is designed for high-speed processing, reducing solution time by over 99% compared to the optimal approach, making it suitable for real-time decision-making, albeit with an average optimality gap of approximately 15–20%. These findings demonstrate that HLR is ideal for high performance computing-based planning, while H3PL facilitates instant response in dynamic cloud environments.