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ComputerAided_Design_Engineering_amp_Manufactur.pdf

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Specifications <strong>Design</strong> Ideas<br />

User<br />

File Manipulator<br />

Graph Editor Display<br />

Petri Net Graphics<br />

Behavior Analyzer Reduction Tool<br />

Synthesizer<br />

Auto<br />

Simulator<br />

Step<br />

Break<br />

Net Protocol<br />

FIGURE 8.10 Structure of the CAD tool for designing, analysis, and synthesis of protocols. (From Reference 2a.<br />

With permission.)<br />

construct a PN either using the “DRAW” button to draw transitions, places and arcs, or using the “FILE”<br />

button to input a PN file. Buttons “Move,” “Pan,” and “Zoom,” to allow large PNs to be drawn. Clicking<br />

the “Pan” button centers the graphics at a chosen location. In addition, the vertical (horizontal) scrollbar<br />

allows the graphics to be moved up and down (left and right). After the PN is drawn or displayed on<br />

the screen, graphical interconnection among places and transitions are translated into internal representations<br />

for further manipulations.<br />

A user can initiate the synthesis by clicking the “Petri” button of the “Synthesis” menu. Afterwards, no<br />

further clicking is necessary for further generations except for clicking the “T-Matrix” button to display the<br />

T-Matrix in the bottom window (called “text_w”) after a new generation. An ex<strong>amp</strong>le of this process to the<br />

synthesis of an automated manufacturing system (Figure 8.11) is shown in Figure 8.12. Shown in the bottom<br />

is a message window “text_w.” After each generation step, this window displays the kind of generation, and<br />

signals any rule violations or whether tokens must be added to places in the NPs.<br />

Upon an interaction generation, a new window pops up that displays an arrow linking two sets of<br />

nodes and invites the designer to pick one node in the left-hand (right-hand) set as ng( nj) . Each time<br />

a node is picked, the tool will call a filtering procedure to eliminate nodes in the set that are sequential<br />

to the node just picked and then redisplay the window. This process continues until both sides are empty<br />

and no more NPs need to be generated for this specific IG.<br />

In the displayed T-Matrix, each structural relationship is expressed by a single letter (e.g., “E”) different<br />

from the two letters (SE) presented earlier. The correspondence is shown in Table 8.2. In addition, Aik �<br />

‘Y’ if Aik � ‘X’ and �i is in a cycle that has a place with more than one input transition; Aik � ‘Z’ if

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