This document discusses time advance mechanisms in discrete event simulation. It describes next event time advance where the simulation clock advances to the next imminent event and is executed. It then continues until a stopping rule is satisfied, ignoring periods of inactivity. Fixed increment time advance advances the simulation clock by a fixed time increment Δt after each update. Any events scheduled during the previous interval are considered to occur at the end of that interval. The document also lists the common components of a discrete event simulation model, including the system state, simulation clock, event list, statistical counters, initialization routine, timing routine, event routine, library routines, and report generator.

1. Time advance
Mechanism
NIKHIL SHARMA | CO15333

2. Track
 WE are here ( Discrete system model)

3. Time advance mechanism
- Discrete event simulation
models are dynamic in nature.
- Time advance mechanism
advances simulated time from
one value to another.
- Simulation clock gives the
current value of simulated time
the.
 Next event time advance
 Fixed increment time advance

4. Time advance mechanism
Next event time advance
 Determine time of occurrence of future events from event list
 Clock advances to next (most Initialize simulated clock to 0
 imminent ) event , which is executed
+ Event execution may involve updating of the list
// obviously we are updating because of arrival and departure procedures
 Continue until stopping rule is satisfied
// As it is algorithm it must stop
//either all events arrived or departed then we are left with nothing
// No of customer delayed or served
 Clock jumps from one period of time to the next and period of inactivity are ignored

5. Time advance mechanism
Fixed event time advance
With this approach the simulation clock is advanced with increment of exactly
∆t time units.
for some appropriate ∆t after each update of the clock,
a check is made to determine
If any event should have occurred during the previous interval of length ∆t.
If one or more events were scheduled to have occurred during this interval then those events are considered to
occur at the end of the interval at system state.

6. ← Next Event time
advance
Fixed Event time
advance →

7. COMPONENT OF A DES MODEL
It comes with certain common components.
Most discrete- event simulation models using next-event time –advance approach…
So the common component must be
System state
Simulation clock
Event list
Statistical counter
Initialization routine
Timing routine
Event routine
Library routines
Report generator and Main program

8. System state:
COLLECTION OF STATE VARIABLES NECESSARY TO DESCRIBE THE SYSTEM STATE
Simulation Clock:
A variable giving the current value of stimulation time.
Event list:
A list containing the next time when each type of event will occur.

9. Statistical counter :
TO ACCUMULATE QUANTITIES FOR OUTPUT
Initialization routine:
Initialize the clock at 0.
Timing routine:
Determine next event time, type } advancing the clock

10. Kindly check the changing
values

11. Event routine:
Carry out logic for each event type
Library routine:
Utility to generate random variants.
Report generator:
To summarize, report result at end

12. SO…