Chapter 11 Queuing models单词卡 | Quizlet

a. the sum of customer waiting costs and service costs.

The goal of queueing analysis is to minimize:

a. the sum of customer waiting costs and service costs.

b. the sum of customer waiting time and service time.

c. service costs.

d. customer waiting time.

e. None of the answer choices is correct.

a. 6 per hour.

A single server queueing system has an average service time of 8 minutes and an average time between arrivals of 10 minutes. The arrival rate is:

a. 6 per hour.

b. 7.5 per hour.

c. 8 per hour.

d. 10 per hour.

e. 12.5 per hour.

c. the order in which customers are processed.

The term queue discipline refers to:

a. the willingness of customers to wait in line for service.

b. having multiple waiting lines without customers switching from line to line.

c. the order in which customers are processed.

d. the reason waiting occurs in underutilized systems.

e. None of the answer choices is correct.

b. 4.

A queueing system has four crews with three members each. The number of "servers" is:

a. 3.

b. 4.

c. 7.

d. 12.

e. 1.

a. It increases exponentially.

If a manager increases the system utilization standard (assuming no change in the customer arrival rate) what happens to the customer waiting time?

a. It increases exponentially.

b. It increases proportionally.

c. It decreases proportionally.

d. It decreases exponentially.

e. No change.

e. Service time

Which of the following is not generally considered as a measure of performance in queueing analysis?

a. The average number waiting in line

b. The average number in the system

c. The system utilization factor

d. The cost of servers plus customer waiting cost

e. Service time

b. Customers move through the system more slowly because utilization is increased.

As the ratio of arrival rate to service rate is increased, which of the following is likely?

a. Customers move through the system in less time because utilization is increased.

b. Customers move through the system more slowly because utilization is increased.

c. Utilization is decreased because of the added strain on the system.

d. The average number in the system decreases.

e. None of the answer choices is correct.

b. 0.4.

A single bay car wash with an exponential arrival rate and service time has cars arriving an average of 10 minutes apart, and an average service time of 4 minutes. The utilization factor is:

a. 0.24.

b. 0.4.

c. 0.67.

d. 2.5

e. None of the answer choices is correct.

c. 0.4

There are 5 servers in a system with an arrival rate of 6 per hour and a service time of 20 minutes. What is the system utilization?

a. 0.1

b. 0.3

c. 0.4

d. 1.2

e. 2.0

c. 4.

A multiple-server system has customers arriving at an average rate of five per hour and an average service time of forty minutes. The minimum number of servers for this system to have a utilization factor under 1 is:

a. 2.

b. 3.

c. 4.

d. 5.

e. None of the answer choices is correct.

b. 0.7

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings (exponential interarrival times). Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays.What is the system utilization?

a. 0.6

b. 0.7

c. 0.8

d. 0.9

e. 1

a. 1.633

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings (exponential interarrival times). Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays.What is the average number of customers waiting in line?

a. 1.633

b. 2.333

c. 2.5

d. 3.966

e. 4

a. 7

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings (exponential interarrival times). Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays.How many minutes does the average customer wait in line?

a. 7

b. 8

c. 9

d. 10

e. 11

d. 10.

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings (exponential interarrival times). Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays.How many minutes does the average customer spend in the system?

a. 7.

b. 8.

c. 9.

d. 10.

e. 11.

c. 0.1

During the early morning hours, customers arrive at a branch post office at the average rate of 45 per hour (exponential interarrival times), while clerks can handle transactions on an average of 4 minutes each (exponential).What is the average number of customers waiting for service if 6 clerks are used?

a. 0

b. 0.01

c. 0.1

d. 1

e. 10

c. 4

Customers filter into a record shop at an average of 1 per minute (exponential interarrivals) where the service rate is 15 per hour (exponential service times).What is the average number of customers in the system with 8 servers?

a. 2

b. 3

c. 4

d. 5

e. 6

d. 0.68

Customers arrive at a video rental desk at the rate of one per minute (exponential interarrival times). Each server can handle 0.4 customers per minute (exponential service times).If there are 4 servers, what is the probability of three or fewer customers in the system?

a. 0.19

b. 0.23

c. 0.63

d. 0.68

e. 0.79

d. 5

Customers arrive at a video rental desk at the rate of one per minute (exponential interarrival times). Each server can handle 0.4 customers per minute (exponential service times).What is the minimum number of servers needed to achieve an average time in the system of less than three minutes?

a. 2

b. 3

c. 4

d. 5

e. 6

A queueing system where a commercial organization provides a service to customers from outside the organization.

commercial service system

every customer has the same service time

constant service times

The most popular choice for the probability distribution of both interarrival times and service times.

exponential distribution

a queue that can hold only a limited number of customers

finite queue

the elapsed time between consecutive arrivals to a queueing system

interarrival time

A queueing system where the customers receiving service are internal to the organization providing the service.

internal service system

The expected number of arrivals to a queueing system per unit time.

mean arrival rate

the expected number of service completions per unit time for a single continuously busy server

mean service rate

priorities for selecting the next customer to begin service when a server becomes free. However these priorities do not affect customers who already have begun service

nonpreemptive priorities

priorities for serving customers that include ejecting the lowest priority customer being served back into the queue in order to serve a higher priority customer that has just entered the queueing system

Preemptive Priority

categories of customers that are given different priorities for receiving service

priority classes

the waiting line in a system. does not include customers who are already being served

queue

The maximum number of customers that can be held in the queue.

queue capacity

the average fraction of time that the servers are being utilized serving customers

utilization factor