Chapter 13, Problem 10QP

The time from when a patient is discharged from North Shore Hospital to the time the discharged patient’s bed is ready to be assigned to a new patient is referred to as the bed assignment turnaround time. If the bed turnaround time is excessive, it can cause problems with patient flow and delay medical procedures throughout the hospital. This can cause long waiting times for physicians and patients thus creating customer dissatisfaction. The admissions RN has assigned a patient care associate to measure the bed turnaround time for a randomly selected bed each morning., afternoon, and evening for 30 days. Following are the bed turnaround time sample observations: Day Day Bed Turnaround Times (min)         1 1 127 135 167 144 151 2 2 140 155 122 135 119 3 3 112 128 97 118 131 4 4 223 135 154 187 150 5 5 181 155 160 172 166 6 6 103 158 145 124 149 7 7 146 135 167 150 178 8 8 104 122 115 137 129 9 9 136 158 137 148 156 10 10 145 163 106 139 170 11 11 84 146 125 98…

One field representative services five customers for a computer manufacturer. Customers request assistance at an average (Poisson-distributed) rate of once every four working days. The field representative can handle an average (Poisson-distributed) of one call per day. Determine: Use Table 1. a. The expected number of customers waiting. (Round your answer to 3 decimal places.)  Expected number of customers waiting             b. The average length of time customers must wait from the initial request for service until the service has been completed. (Round your answer to 2 decimal places.)  Average length of time            days c. The percentage of time the service rep will be idle. (Round your answer to 1 decimal place.)  Percentage of Idle time             d. By how much would your answer to part a be reduced if a second field rep were added? (Round your answer to 3 decimal places.)  Reduced number of customer(s)              Please answer part C

6. The Garrett-Tompkins Company provides three copy machines in its copying room for the use of its employees. However, due to recent complaints about considerable time being wasted waiting for a copier to become free, management is considering adding one or more additional copy machines. During the 2,000 working hours per year, employees arrive at the copying room according to a Poisson process at a mean rate of 40 per hour. The time each employee needs with a copy machine is believed to have an exponential distribution with a mean of 4 minutes. The lost productivity due to an employee spending time in the copying room is estimated to cost the company an average of $40 per hour. Each copy machine is leased for $4,000 per year. Find the following values for this system: λ, μ, Cs, Cw. Then use the Excel template to determine how many copy machines the company should have to minimize its expected total cost per hour. List your result in the following table. : S 3 4 5 P E(TC) = E(SC) + E…

What are the most common measures of system performance in a queuing analysis?

Customers of Golden Crust Bakery arrive at the single cashier at the rate of 10 per hour. The average service time for the cashier is five minutes. Arrivals follow a Poisson distribution, and service times follow an exponential distribution. a. What is the average utilization of the cashier? b. What is the average number of customers in the system? c. What is the average number of customers in line? What is the average time spent in the system? e. What is the average time spent in line? d.

Queuing Models

Discuss briefly the relationship between waiting line analysisand quality improvement.

Burger Dome sells hamburgers, cheeseburgers, French fries, soft drinks, and milk shakes, as well as a limited number of specialty items and dessert selections. Although Burger Dome would like to serve each customer immediately, at times more customers arrive than can be handled by the Burger Dome food service staff. Thus, customers wait in line to place and receive their orders. Suppose that Burger Dome analyzed data on customer arrivals and concluded that the arrival rate is 33 customers per hour and 1 customer processed per minute. Compare a multiple-server waiting line system with a shared queue to a multiple-server waiting line system with a dedicated queue for each server. Suppose Burger Dome establishes two servers but arranges the restaurant layout so that an arriving customer must decide which server's queue to join. Assume that this system equally splits the customer arrivals so that each server sees half of the customers. How does this system compare with the two-server…

12-11 The Rockwell Electronics Corporation retains a service crew to repair machine breakdowns that occur on an average of λ=3 per day (approximately Poisson in nature). The crew can service an average of μ=8 machines per day, with a repair time distribution that resembles the exponential distribution. a. What is the utilization rate of this service system? b. What is the average downtime for a machine that is broken? c. How many machines are waiting to be serviced at any given time? d. What is the probability that more than one machine is in the system? Probability that more than two are broken and waiting to be repaired or being serviced? More than three? More than four?