I have some time data that was collected for properties for sources, processors, operators, etc. I used a statistical distribution (uniform) to generate random process times between a minimum and maximum value. However each time I run the simulation, the process times it uses are the exact same as the previous time I ran the simulation. Essentially each time the simulation is run, it is not random compared to the previous one. How can I make each time I run the simulation different from the previous time?