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Extended logical Petri nets are proposed to improve logical Petri nets, and the related firing rules and state reachability graph are introduced. Their attributes, place arrival time, and priority function are defined for each token, batch processing wait time and transition firing duration are defined for each logical input/output transition, and firing duration is defined for each ordinary transition...
It is complex and difficult to perform the rescue vehicle scheduling to handle forest fires in order to reduce the operational cost and improve the efficiency of fire-extinguishing services. A new research issue arises when a) decision-makers want to minimize the number of rescue vehicles while minimizing the rescue time; and b) decision-makers prefer to complete the fire-extinguishing task fast given...
Petri nets (PNs) are well utilized as a visual and mathematical formalism in modeling, analysis and control of urban traffic. This work adopts timed Petri nets to design a traffic-signal-based emergency control policy such that emergency response is provided and the incident-induced large-scale congestion is prevented. A reachability graph method is adopted to demonstrate how the models are used to...
A multi-cluster tool is composed of a number of single-cluster tools linked by buffering modules. The capacity of a buffering module can be one or two. Aiming at finding an optimal one-wafer cyclic schedule, this work explores the effect of two-space buffering modules on the performance of a multi-cluster tool. The tool is modeled by a kind of Petri nets. The dynamic behavior of robot waiting and...
It has been shown that, for dual-arm cluster tools with wafer revisiting, a swap strategy may not be optimal. To improve the performance of such a system, a Petri net model is developed in this work. Based on it, dynamical behavior of the wafer production process is analyzed. Then, two new scheduling methods called 2-wafer cyclic schedules are presented. Cycle time analysis shows that, under some...
There are wafer fabrication processes in cluster tools that require revisiting. It is shown that swapping is efficient in operating a dual-arm cluster tool. For dual-arm cluster tools with wafer revisiting, if a swap strategy is applied, it forms a three wafer periodical process with three wafers completed in each period. Such a period contains three cycles in a revisiting process and another three...
An advanced driving assistance system (ADAS) becomes more and more important since it can improve driving safety. It is composed of a human driver and an automated system called co-pilot. To make it effective, the driver and co-pilot should properly cooperate. Hence, it is very important to define and model their cooperation behavior such that an ADAS can be effectively designed and realized. This...
Protocol-level mismatch is one of the most important problems in service composition. The commonly used reachability exploration method focuses on verifying deadlock-freeness. When this property is violated, the states and traces in the reachability graph only give clues to re-design the composition. The process must then repeat itself until no deadlock is found. In this paper, multiple Web service...
Because of various constraints, the short-term scheduling of crude oil operations in refinery is very complicated. So far, there is no effective technique and tool. To solve this problem, this paper models the system by a hybrid Petri net and a short-term schedule is seen as a series of control commands. With this model, schedulability analysis of systems with a single distiller is conducted and schedulability...
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