MGT 560 Queuing System Simulation Stochastic Modeling © Victor E. Sower, Ph.D., C.Q.E. 2007
Steps in Simulation Process 1.Define problem 2.Define important variables in problem 3.Collect data 4.Construct mathematical model 5.Validate model 6.Define experiments to run 7.Run experiments 8.Consider results (possible model modification) 9.Decide on course of action Victor E. Sower, Ph.D., C.Q.E. 2007
Advantages of Simulation Straightforward and flexible Can analyze complex real-world situations Can use any distributions—not just standard ones Time compression Can address “what-if” questions Off-line Can study interactions of individual variables and components Victor E. Sower, Ph.D., C.Q.E. 2007
Limitations of Simulation Expensive and time consuming Does not generate optimal solutions The results from the model are limited by the quality of the design of the model Each simulation model is unique to a particular problem Victor E. Sower, Ph.D., C.Q.E. 2007
Types of Queuing Systems Single channel; Single phase Victor E. Sower, Ph.D., C.Q.E Channel – the number of parallel servers Phase – the number of servers in sequence
Types of Queuing Systems Multiple channel; Single phase Victor E. Sower, Ph.D., C.Q.E. 2007
Types of Queuing Systems Single channel/Multiple phase Victor E. Sower, Ph.D., C.Q.E. 2007
Types of Queuing Systems Multiple channel/Multiple phase Victor E. Sower, Ph.D., C.Q.E. 2007
Data Collection Source of customers – Infinite – Finite Victor E. Sower, Ph.D., C.Q.E. 2007
Data Collection Arrival Rate/Interarrival Time – Arrival Rate (Poisson) – Interarrival Time (Exponential) Victor E. Sower, Ph.D., C.Q.E. 2007
Data Collection Service Rate/Service Time – Service Rate (Poisson) – Service Time (Exponential) Victor E. Sower, Ph.D., C.Q.E. 2007
Data Collection Queue Discipline – FCFS – LIFO – Random – Others Victor E. Sower, Ph.D., C.Q.E. 2007
Data Collection Queue Length – Infinite – Finite Balking Victor E. Sower, Ph.D., C.Q.E. 2007
System Operating Characteristics Results from Model LAvg. no. of customers in system L q Avg. no. of customers in the queue WAvg. time customer spends in system W q Avg. time customer spends in queue pUtilization rate Victor E. Sower, Ph.D., C.Q.E. 2007
System Considerations Waiting line costs Service quality Psychology of waiting Balking Victor E. Sower, Ph.D., C.Q.E. 2007