Class Queueing Issue...

[Green_Hornet]

I am trying to model two type of queueing issues: first, where class enrollees are queued in a population until a class starts periodically, and second, where class enrollees are queued until a minimum population (e.g., class size) is acheived, then a class is started. I've looked thorugh the queueing, delay and conveyor issues in the modeling guide, but can't put my thump on something that would model these issues. Any suggestions? TIA ~

[bob@vensim.com]

To start with a population size just use

students waiting = INTEG(students signing up - students starting class,0)
students starting class = IF THEN ELSE(students waiting >= Class Size,Class Size/TIME STEP,0)

To start periodically use

students waiting = INTEG(students signing up - students starting class,0)
students starting class = IF THEN ELSE(class start time,students waiting/TIME STEP,0)
class start time = IF THEN ESLE(MODULO(Time,3) = 0,1,0)

for quarterly starts in a monthly model.

You can also use the QUEUE FIFO functions if you need to track details.

[Green_Hornet]

Thanks ~ I'll try this!