Minutes of meeting 25 Jan 2002

Meeting with wjk at 12:30pm

Meeting opened 12.30pm

Present: William Knottenbelt, Raphael Goldberg, Peter Howarth, Daniel Justice, Michelle Osmond, Zhu Tan, Aleksandar Trifunovic

What we've done since the last meeting

• Michelle: Extended Petri nets prototype editor to draw and move places, transitions and arcs, updating the DOM in memory. Dynamically-generated, editable properties box to show possibilities of the JDOM system. (See Links for download).
• Tan: Finished OMT/UML diagrams for the conventional object approach.
• Daniel: Done GUI framework (menus and buttons).
• Raphael: First draft of Report I

Discussion

• For reasons discussed before, will use the JDOM-based system. The big reason is that it allows us to build a program which is designed to be extended to support new types of net, relatively easily compared to the usual fixed-object approach. This is a feature which most other petri net editors do not support.
• We will however maintain an object hierarchy for the graphics/animation/simulation part of the system, very similar to the conventional approach, but with pointers to the elements within the JDOM (rather than storing data in the objects).
• In the graphics objects, include access (set,get) functions to provide data protection, for the animation/simulation part to use, but the active parts of the editor (eg properties box) will need unrestricted access to the DOM. This shouldn't be a problem as that part of the system is unlikely to be extended by module authors, and may not even need to be changed when adapting the program to support new net types.
• Worth getting the editor looking good (circles), as that's what gives the first impression.

Report

• Initial draft looks good.
• Add description of what JDOM is and why we're using it (extensibility).
• OMT diagram of the object (label) hierarchy, and high-level description of how the rest of the program should work.

Meeting closed 1:30pm

Meeting in 343

Present: Raphael Goldberg, Peter Howarth, Daniel Justice, Michelle Osmond, Zhu Tan, Aleksandar Trifunovic

Meeting opened 1:30pm

• Looking at Renew: nice interface. Automatic creation/deletion of transitions, connecting arcs. Simulator - nice, but too fast - would be nice to include a changeable timestep. Simulator runs and then returns to original marking when it finishes.
• Editor/display are closely linked (~same thing). Get the basics up and running fast, then do the clever stuff (like Renew's features) later
• Animator (click on transition to fire) also needs good knowledge of the editor/display part, so better to not make it a module.
• Modules: Invariance Analysis, State Space, Simulator (later), Markov Chain (later)

To do:

• Aleksander: Invariance Analysis module
• Tan: update the OMT diagram and send to Peter
• Michelle: write JDOM summary, email PNML people, sort out GUI
• Daniel: sort out GUI
• Peter: continue writing the report, look at subnets
• Raphael: state space, graph theory module

Meeting closed 2:30pm

Next meeting: Monday (28th), 12:30pm in 343 (or common room)