Today was my last day at Spring Sim. I attended most of a talk in the morning, which was actually a workshop on conceptual modeling. I arrived late (I’m so exhausted from this conference, I didn’t expect that). When I arrived, Dr. Heavey was presenting his work, and he discussed various approaches studied. These included Petri Nets, and UML State Machines. After his talk, I commented on how UML state charts are very similar to what he was describing. This brought an eruption of laughter from the audience, although I had not finished my comment and question. It was rather annoying, since YetiSim uses a modified version of UML for modeling. I expect that at least some parts of YetiSim’s execution graphs could be useful. You see, this is why they are not called state machines anymore, and are execution graphs now. People presume that they know what you are talking about, when you say “modified version” they don’t ask how it is modified, they assume it’s something small, not a radical shift of ideas. During the break, I obtained some contact information for Dr. Heavey. I would like to learn more about his work, and I intend to read his paper. However the break time conversation was dominated by discussions of the problems, with an emphasis on why UML is horrible for modeling. I admit I don’t have enough of a background in conceptual modeling to have an intelligent argument, but I would have enjoyed the conversation. This is why I shouldn’t use the word UML and will never use the word “state diagram” in association with how YetiSim runs.
The workshop featured other presentations, including one from Boeing and NATO. The talk from NATO was interesting, and the presenter outlined their goals. The presenter from Boeing was very energetic, although the bottom of his slides had something stating to the effect that disclosure of details was forbidden except under conditions presented in the title slide (which I wasn’t in the room to see). In my opinion, such disclaimers have no place at an academic conference They belong to select groups behind closed doors. The presentation from Boeing was very interesting, I just didn’t like the caption at the bottom of the slides. It’s interesting just to hear how much Boeing uses simulation.
Otherwise, I checked out of the hotel today and spent some time reading before departing on the train back home (which is where I’m writing this right now). Deborah has expressed interest in forming a working group at U of T on conceptual modeling. I think that would be a great idea, and the work of the group could benefit both YetiSim, and give an opportunity for U of T to become more involved in simulation. U of T is fairly open to interdisciplinary pursuits in my experience, and it would be wonderful to have a group composed of engineers, computer scientists, cognitive scientists, and others to examine methods of simulation modeling.
Another problem with YetiSim came up today. It has no ability to pre-empt tasks. I have to figure out a solution to this one. Also the interconnection of entities is not something that has been well planned, when you have things that are interacting with each other. The example presented was a tug boat and a tanker, which require interactions with each other for an effective simulation.
A few presentations discussed semantic web, and it sounded like something interesting to explore.
Overall it was an interesting experience, this was my first conference. I look forward to collaborating in future with the people I met at the conference.
Posted by AJ Guillon (April 16, 2008)
