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Clinical Pathway (CP) is very complicated and has many exceptional variations. Generally, its treatment course and control steps can not be totally predefined. Meanwhile, the CP embodies the “Re-flow” therapy features, which is very hard to model, control and manage. Therefore, combined modular modelling method and structure changing mechanisms, a Modular Colored Petri Net with changeable structure (MCPN-CS) workflow modelling method is proposed. A special type of transition called main bus gate (MBG) is introduced to solve the “Re-flow” problem. Moreover, aimed at the variations of the CP, the workflow model for the CP can be reconfigured dynamically by using the mechanism of change-by-modification (CBM) and change-by-composition (CBC). A case study on the osteosarcoma CP evolution workflow modelling is constructed and the modelling is analyzed by presented deadlock detection algorithms (DDA). The result validates that the proposed method can noticeably enhance the flexibility, adaptation, reusability and maintainability workflow model for the CP.

Semiconductor wafer fabrication system (SWFS) is the most complex and capital-intensive phase in the entire semiconductor manufacturing cycle. With characteristics of re-entrant processing routes, equipment uncertainty, product diversity and improving technologies, great challenges are presented in SWFS's modeling, scheduling and simulation. To implement efficient production control, this paper provides a timed extended object-oriented Petri nets (TEOPNs) approach to performance modeling, real-timed dispatching and simulation of SWFSs. The TEOPNs models are constructed in a hierarchy to accord with the real-world SWFS's organization, and a new type of signal place is added into the TEOPNs to respond the dynamic states of all processing facilities. A novel autonomy and coordination-based real-time dispatching mechanism (A&C-RDM) is developed in this paper, which executes under the support of the TEOPNs-based hybrid real-time dispatching control system (HRDCS). Owning to the ability of gathering dynamic real-time information of all production facilities and WIP products, the HRDCS can make adaptive dispatching decisions according to the local and global real-time processing status. Two sets of key elements of real-time dispatching, i.e. the state thresholds and dispatching rules, are defined in the HRDCS so that the A&C-RDM can integrate different types of dispatching rules. A set of simulation experiments prove the efficiency of the proposed modeling and dispatching algorithm. In summary, the proposed TEOPNs, HRDCS and A&C-RDM form the cornerstones of a real-time dispatching simulation prototype of SWFS, and the work described in this paper carries out an advanced integrated ''modeling-dispatching-simulation'' methodology.

In this paper, extended object-oriented Petri nets (EOPNs) are proposed for the effective modelling of semiconductor wafer fabrication systems (SWFSs). To cope with their complexity in terms of the re-entrant process route and the mixed production mode, a special type of transition called main-bus gate is introduced, which may lead each kind of product to undergo every re-entrant processing stage. In addition, the hierarchical approach is also applied to cope with the complexity. An etching area that processes 0.25 µm logic IC products is taken as an illustration to present the detailed modelling procedures by EOPNs, and the resulting model validates that the EOPNs may cope well with complex SWFSs modelling.

In this paper we propose an extended object-oriented Petri nets (EOPNs) for effective modeling of large-scale complex re-entrant manufacturing systems (ReMSs). To cope with their complexity because of the re-entrant process route and the mixed production mode, a special type of transition called a main-bus gate (MBG) is introduced, which can cause products to undergo every re-entrant manufacturing stage. A hierarchical approach is also applied to cope with the complexity. As a typical large-scale complex ReMS, the semiconductor wafer fabrication system (SWFS) is taken as an example for demonstrating the proposed EOPNs. A case study is provided to show the modelling procedures, and the resulting model validates that the EOPNs can cope well with the modelling complexity of large-scale complex ReMSs.

Real-time scheduling of semiconductor wafer fabrication system (SWFS) is complicated due to the following factors. re-entrant product flow, high uncertainties in operations and rapidly changing products and technologies. This paper presents a simulation platform for real-time scheduling of SWFS, which is designed and developed based on extended object-oriented petri net (EOPN) to describe the complicated wafer fabrication process and serve as the foundation of real-time scheduling. In addition, a dynamic bottleneck dispacthing (DBD) algorithm is designed to detect bottlenecks in a timely way and make adaptive dispatching decisions according to the real-time conditions. The results of the simulation experiments and analysis show that the DBD algorithm is superior to CR+FIFO and EDD methods.

Modern microelectronics manufacturing may be described by re-entrant manufacturing systems (ReMS). To be competitive, ReMS are designed to run fully automated and effective production control and schedule policies are pursued, however, a high-fidelity system model is the prerequisite. In this paper, an extended object-oriented Petri nets (EOPN) is proposed to cope with the complexity of re-entrant process routes and mixed production modes. To ensure the resulting EOPN model is deadlock free, an algorithm is introduced to analyze the resulting EOPN model so that all possible deadlock situations may be detected and avoided before any control and schedule policy is implemented. In addition, formal description of the related conflicts and resolving algorithm are also presented in this paper.