CSCE 782: News

Also, unless you have talked to me about it, the due date for PS 6 is Monday 2002-12-09@12:00:00, in the dropbox.

• José M. Vidal and Paul Buhler. Teaching multiagent systems using robocup and biter.The IMEJ of Computer-Enhanced Learning, 4(2), 2002. Also view the online version with RealVideo of the games.
• Paul Buhler and José M. Vidal. Biter: A platform for the teaching and research of multiagent systems' design using robocup. In A. Birk, S. Coradeschi, and S. Tadokoro, editors, RoboCup 2001: Robot Soccer World Cup V. LNCS/LNAI Lecture Notes Volume 2377. Springer-Verlag, Berlin Heidelberg, 2002.
• José M. Vidal and Paul Buhler. Using robocup to teach multiagent systems and the distributed mindset. In Proceedings of the 33rd ACM Technical Symposium on Computer Science Education, 2002. Selected as one of the 10 best SIGCSE 2002 papers.

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java.lang.NullPointerException
        at CalendarBean.JCalendar.setLocale(JCalendar.java:98)

Actually, I think, Meeting Scheduler works on Solaris, too. The thing is it doesn't work with java1.4. I changed something in your the makefile.

JAVA=java  =>
JAVA=/usr/local/java1.3/bin/java

And it seems working, although I don't know why exactly.

I got this trouble too (on Linux J2SDK 1.4). As I undestand it is not OS depended bug, but JVM version depended. CalendarBean (which used in MeetingScheduler) don't work in JVM 1.4.

I had some problems integrating it in the example since the paths somehow changed but it works fine with this jcalendar.

"Potter predicted the arrival of open-source calendar servers would lead to an explosion of public calendaring on the Web."

1. Implement the obvious solution.
2. Write a list of all the problems or opportunities for improvement (for want of a more positive name) with that solution.
3. Come up with a system that overcomes 2. Make sure it still performs better than the obvious solution.

to-report target-in-sight [the-target]
  locals [angle]
  set angle abs (towards the-target - heading)
  set angle min list angle (360 - angle)
  report angle <= radar-amplitude / 2
end

• Some of you pursued a very regimented scheme of assigning tiles to agents which did not allow for any opportunistic behavior. Remember, it is important for agents to be goal-driven as well as reactive. For example, if a hole appears right next to the tile you are pushing, use it!
• There were several implementations were some of the robots stayed fixed (more on this below). I must admit that I was surprised at the quality of these solutions. I would have assumed that having a robot stay put while there are tiles available would really hurt one's score more. I believe that the reason there was not as much a noticeable difference is because in the other solutions, where the robots always moved, the robots would interfere with each other and undo some of the gains. I guess sometimes the best thing to do is nothing.
• The reason many of you had fixed robots and abandoned tiles is because many of you were assigning to each tile the robot that was closest to that tile (yes, you were doing doing this). The problem arises when there is one robot that is closer than any other robot to two or more tiles. In that case only one of those tiles will have a robot assigned to it, the rest will be orphaned.
• A few of those high scores I mentioned earlier were achieved with a bit of "cheating". Several of you changed the move-one function to not move other robots. Such a change violates the spirit of the problem. I did not take off any points for this. In the future I hope you will try to obey the spirit of the problem. I realize this is hard since we do not have complete specifications of these problems.
• The problem of dead tiles, which shows up when the program tries to ask a dead tile to do something, is due to the inherent parallelism in netlogo. Since all the robots are moving in parallel it is possible for robot-1 to get a reference to tile-1, then robot-2 push tile-1 into a hole and kill it, then robot-1 ask its reference to tile-1 to do something. If you want to prevent these types of problems you should look into without-interruption.