Now we want to do systematic iterations. You should write a script which manages those iterations. One option is perl; shell scripts work well, too. Also, some clever Makefile writing is an option. The script does the following:
Run the usim on a given plans file.
Generate a random 10% trips file.
Run the router on the 10% trips file using the events from the last simulation.
Merge the plans.
Run the usim again.
Etc.
Keep events files for all iterations.
Compress (e.g. gzip) all output files.
Note that you can derive this information from the events files.