Simulate with Different Intergeneration Times

By changing the intergeneration time (that is, the reciprocal of the entity arrival rate) in the Time-Based Entity Generator block, you can see when entities accumulate in the queue. Try this procedure:

1. Double-click the Time-Based Entity Generator block to open its dialog box, set the Period parameter to 0.85, and click OK. This causes entities to arrive somewhat faster than the Single Server block can process them. As a result, the queue is not always empty.

2. Save and run the simulation. The plot whose title bar is labeled Signal Scope1 represents the queue length. The figure below explains some of the points on the plot. The vertical range on the plot has been modified to fit the data better.

3. Reopen the Time-Based Entity Generator block's dialog box and set Period to 0.3.

4. Run the simulation again. Now the entities arrive much faster than the server can process them. You can make these observations from the plot:

· Every 0.3 s, the queue length increases because a new entity arrives.

· Every 1 s, the queue length decreases because the server becomes empty and accepts an entity from the queue.

· Every 3 s, the queue length increases and then decreases in the same time instant. The plot shows two markers at T = 0, 3, 6, and 9:

5. Reopen the Time-Based Entity Generator block's dialog box and set Period to 1.1.

6. Run the simulation again. Now the entities arrive more slowly than the server's service rate, so every entity that arrives at the queue is able to depart in the same time instant. The queue length is never greater than zero for a positive amount of time.