In DDDAMS paradigm, the fidelity of a complex simulation model adapts to available computational resources by incorporating dynamic data into the executing model, which then steers the measurement process for selective data update. Real-time inferencing for a large-scale system may involve hundreds of sensors for various quantity of interests, which makes it a challenging task considering limited resources. In this work, a Sequential Monte Carlo method (sequential Bayesian inference technique) is proposed and embedded into the simulation to enable its ideal fidelity selection given massive datasets. As dynamic information becomes available, the proposed method makes efficient inferences to determine the sources of abnormality in the system. A parallelization frame is also discussed to further reduce the number of data accesses while maintaining the accuracy of parameter estimates. A prototype DDDAMS involving the proposed algorithm has been successfully implemented for preventive maintenance and part routing scheduling in a semiconductor supply chain.
INTRODUCTIONIn today's global and competitive market, different companies (e.g. suppliers, manufacturers, retailers, distributors, and transporters) form a supply chain to transform raw materials into finished goods and distribute the finished goods to the customers in a collaborative manner. For success in a supply chain, coherent planning and control across as well as within each of strategic, tactical, and operational issues are of critical importance (Beamon 1999, Son et al. 2002and Samaddar et al. 2006). In the decision making process of coherent planning and control, the latest information reflecting immediate supply chain status is to be used to make planning and control orders in the best possible harmony with current systems capabilities. However, the large-scale, dynamic and complex nature of supply chains makes coherent planning and control very challenging. While it is true for the strategic and tactical levels, it becomes even more so at the operational level as the number of parameters as well as the frequency of update for each parameter grow significantly. In order to enable timely planning, monitoring, and control of these supply chains at the operational level in an economical and effective way, we have earlier proposed dynamic-data-driven adaptive multi-scale simulation (DDDAMS) architecture (Celik et al. 2007). This research is believed as the first efforts available in the literature to 1) handle the dynamicity issue of the system by selectively incorporating up-to-date information into the simulation-based real-time controller, and 2) introduce adaptive simulations that are capable of adjusting their level of detail according to the altering conditions of a supply chain in the most economic way. The components of DDDAMS architecture include 1) a real-time DDDAM-Simulation, 2) grid computing modules, 3) a web service communication server, 4) a database (online and archival), 5) various sensors, and 6) a real system. In addition, major functions ...