Identify following queuing model's elements: customers, services, design of service facility, service discipline, queue size limit$,$ calling source limit$.$ Draw a flow chart which show who$/$what arrive at which queue and then go to the which server$($s$).($refer to the flow chart on lecture note Topic One page $1).$A computer center is equipped with three digital computers, all of the same type and capability. The number of users in the center at any time is equal to $10.$ For each user, the time for writing $($and key punching$)$ a program is exponential with mean rate $5$ per hour. Once a program is completed, it is sent directly to the center for execution. The computer time per program is exponentially distributed with mean rate $2$ per hour. Assuming that the center is in operation on a full$-$time basis, and neglecting the effect of computer down