EAAI Journal 2026 Journal Article
HarmonyRouting with traffic impact prediction based on graph neural network for large-scale semiconductor fabrication
- Younkook Kang
- Kwangyoung Im
- Sangmin Lee
- Sungzoon Cho
Recently, automated material handling systems, which operate without human intervention, have been developed for smart semiconductor factories. An overhead hoist transport (OHT), a vehicle robot that transfers carriers between production equipment along a railway network, is an effective tool for automated material handling systems. To improve routing decisions, many studies have attempted to predict the traffic of OHTs, mainly focusing on routes from an individual OHT perspective because of the associated complexity. To overcome the limitations of existing studies, we propose HarmonyRouting, which is a prediction-based system-perspective routing method designed to optimize overall traffic flow by balancing individual vehicle routes. First, a partitioned attention-based graph neural network was proposed to efficiently and effectively predict traffic for large-scale fabrication plant layouts. Second, the concept of vehicle traffic impact caused by congestion on a path was defined and modelled. Third, traffic impact value was applied to the routing model for system-view decisions. Its architecture was designed to enhance practical application. The performance of the model was evaluated using simulations with the actual fabrication plant layout and the largest number of OHTs ever studied. Our model outperformed other models in terms of average delivery time and delay. Our model represents an innovative approach towards realizing a fully autonomous manufacturing factory.