Question 1

A(n)________ queuing system is one in which the customer receives service from only one station and then exits the system.

Accepted Answer

The answer of A(n)________ queuing system is one in which...

Question 2

The two characteristics of the waiting line itself are whether its length is limited or unlimited and the discipline of the people or items in it.

Accepted Answer

A) True 
 B)False

Question 3

A waiting-line system that meets the assumptions of M/M/S has λ = 5,μ = 4,and M = 2.For these values,Po is approximately 0.23077 and   is approximately 2.05128.The average time a unit spends in this system

Accepted Answer

A) is approximately 0.1603. 
B) is approximately 0.2083. 
C) is approximately 0.4103. 
D) is approximately 0.8013. 
E) cannot be calculated because λ is larger than μ. 
A) is approximately 0.1603. 
B) is approximately 0.2083. 
C) is approximately 0.4103. 
D) is approximately 0.8013. 
E) cannot be calculated because λ is larger than μ.

Question 4

Students arrive randomly at the help desk of a computer lab.There is only one service agent,and the service time varies from one student to the other.Provide the most likely characteristics for this system.
a.name of model
b.number of channels
c.number of phases
d.arrival rate distribution
e.service time distribution
f.population size
g.queue discipline

Accepted Answer

Single channel syste

Question 5

The greater the margin by which the arrival rate exceeds the service rate,the better the performance of the waiting line.

Accepted Answer

A) True 
 B)False

Question 6

In a repetitive focus factory,the number of channels available for the processing of a certain part would likely refer to

Accepted Answer

A) the number of successive operations that have to be performed on that part. 
B) the number of machines doing the same necessary operations. 
C) the number of parts waiting to be processed. 
D) the number of workers waiting to perform their task. 
E) the number of units with defects requiring rework. 
A) the number of successive operations that have to be performed on that part. 
B) the number of machines doing the same necessary operations. 
C) the number of parts waiting to be processed. 
D) the number of workers waiting to perform their task. 
E) the number of units with defects requiring rework.

Question 7

A college registrar's office requires you to first visit with one of three advisors and then with one of two financial professionals.This system is best described as

Accepted Answer

A) single channel,single phase system. 
B) single channel,multi-phase system. 
C) multi-channel,single phase system. 
D) multi-channel,multi-phase system. 
E) multi-channel,cross-phase system. 
A) single channel,single phase system. 
B) single channel,multi-phase system. 
C) multi-channel,single phase system. 
D) multi-channel,multi-phase system. 
E) multi-channel,cross-phase system.

Question 8

A dental clinic at which only one dentist works is open only two days a week.During those two days,the traffic is uniformly busy with patients arriving at the rate of three per hour.The doctor serves patients at the rate of one every 15 minutes.
a.What is the probability that the clinic is empty (except for the dentist)?
b.What percentage of the time is the dentist busy?
c.What is the average number of patients in the waiting room?
d.What is the average time a patient spends in the office (wait plus service)?
e.What is the average time a patient waits for service?

Accepted Answer

(a)Po = 1 - 3/4 = 0.25; (b)The dentist i

Question 9

A concert hall,employing both ticket takers and ushers to seat patrons,behaves typically as a

Accepted Answer

A) multi-channel,single phase system. 
B) multi-channel,multi-phase system. 
C) single channel,single phase system. 
D) single channel,multi-phase system. 
E) multi-channel,cross-phase system. 
A) multi-channel,single phase system. 
B) multi-channel,multi-phase system. 
C) single channel,single phase system. 
D) single channel,multi-phase system. 
E) multi-channel,cross-phase system.

Question 10

The common measures of a queuing system's performance include

Accepted Answer

A) probability that the service facility will be idle,average queue length,probability that the waiting time will exceed a specified duration. 
B) average time each customer spends in the system,probability that the service system will be idle,average time each customer spends in the queue. 
C) average queue length,maximum time a customer may spend in the queue,the utilization factor for the system. 
D) average time each customer spends in the system,maximum queue length,probability of a specific number of customers in the system. 
E) average time that the service facility is idle,minimum queue length,probability that the waiting time will exceed a specified duration. 
A) probability that the service facility will be idle,average queue length,probability that the waiting time will exceed a specified duration. 
B) average time each customer spends in the system,probability that the service system will be idle,average time each customer spends in the queue. 
C) average queue length,maximum time a customer may spend in the queue,the utilization factor for the system. 
D) average time each customer spends in the system,maximum queue length,probability of a specific number of customers in the system. 
E) average time that the service facility is idle,minimum queue length,probability that the waiting time will exceed a specified duration.

Question 11

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour.What is the probability that the waiting line is empty?

Accepted Answer

Po = 1 - λ

Question 12

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour.What is the average time a unit spends in the system and the average time a unit spends waiting?

Accepted Answer

Ws = 1 / (μ- λ)= 1 /

Question 13

At the order fulfillment centre of a major mail-order firm,customer orders,already packaged for shipment,arrive at the sorting machine to be sorted for loading onto the appropriate truck for the parcel's address.The arrival rate at the sorting machine is at the rate of 140 per hour following a Poisson distribution.The machine sorts at the constant rate of 150 per hour.
a.What is the utilization rate of the system?
b.What is the average number of packages waiting to be sorted?
c.What is the average number of packages in the sorting system?
d.How long must the average package wait until it gets sorted?

Accepted Answer

(a)The utilization rate is = 140/150 = 0

Question 14

You have seen that,in an M/D/1 problem,the average queue length is exactly one-half the average queue length of an otherwise identical M/M/1 problem.Are all other performance statistics one-half as large also? Explain.

Accepted Answer

Only the average queue length

Question 15

Which of the following is an example of a finite arrival population?

Accepted Answer

A) copy machines in a copying shop that break down 
B) students at a large university registering for classes 
C) shoppers arriving at a supermarket 
D) cars arriving at a suburban car wash 
E) customers arriving at a coffee shop 
A) copy machines in a copying shop that break down 
B) students at a large university registering for classes 
C) shoppers arriving at a supermarket 
D) cars arriving at a suburban car wash 
E) customers arriving at a coffee shop

Question 16

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1.Units arrive at this system every 12 minutes on average.Service takes a constant 8 minutes.The average number in the system   is approximately

Accepted Answer

A) 2.25. 
B) 2.5. 
C) 3.0. 
D) 1.33. 
E) 5.0. 
A) 2.25. 
B) 2.5. 
C) 3.0. 
D) 1.33. 
E) 5.0.

Question 17

Four of the most widely used waiting line models-M/M/1 or A,M/M/S or B,M/D/1 or C,and Limited population or D-all share three characteristics,which are

Accepted Answer

A) normal arrivals,FIFO discipline,and normal service times. 
B) Poisson arrivals,FIFO discipline,and a single-service phase. 
C) Poisson arrivals,FIFO discipline,and exponential service times. 
D) Poisson arrivals,no queue discipline,and exponential service times. 
E) Poisson arrivals,long queue discipline,and multiple service times. 
A) normal arrivals,FIFO discipline,and normal service times. 
B) Poisson arrivals,FIFO discipline,and a single-service phase. 
C) Poisson arrivals,FIFO discipline,and exponential service times. 
D) Poisson arrivals,no queue discipline,and exponential service times. 
E) Poisson arrivals,long queue discipline,and multiple service times.

Question 18

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 7 vehicles per day (approximately Poisson in nature).The mechanic crew can service an average of μ= 11 vehicles per day with a repair time distribution that approximates an exponential distribution.
a.What is the utilization rate for this service system?
b.What is the average time before the facility can return a breakdown to service?
c.How much of that time is spent waiting for service?
d.How many vehicles are likely to be waiting for service at any one time?

Accepted Answer

(a)Utilization is ρ = 7 / 11 =

Question 19

As the average service rate μ increases,the shape of the negative exponential distribution of service times

Accepted Answer

A) grows steadily steeper without limit. 
B) has an ever steeper slope that eventually turns positive. 
C) becomes less gently curved as it moves ever closer to the graph origin. 
D) takes on a more uniform slope over a wide range of service times. 
E) changes in appearance from convex to concave. 
A) grows steadily steeper without limit. 
B) has an ever steeper slope that eventually turns positive. 
C) becomes less gently curved as it moves ever closer to the graph origin. 
D) takes on a more uniform slope over a wide range of service times. 
E) changes in appearance from convex to concave.

Question 20

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 8 vehicles per day (approximately Poisson in nature).The mechanic crew can service an average of μ= 11 vehicles per day with a repair time distribution that approximates an exponential distribution.The crew cost is approximately $300 per day.The cost associated with lost productivity from the breakdown is estimated at $150 per vehicle per day (or any fraction thereof).What is the expected cost of this system?

Accepted Answer

The number of vehicles out of

Exam 24: Waiting-Line Models

A(n)________ queuing system is one in which the customer receives service from only one station and then exits the system.

The two characteristics of the waiting line itself are whether its length is limited or unlimited and the discipline of the people or items in it.

A waiting-line system that meets the assumptions of M/M/S has λ = 5,μ = 4,and M = 2.For these values,Po is approximately 0.23077 and is approximately 2.05128.The average time a unit spends in this system

The greater the margin by which the arrival rate exceeds the service rate,the better the performance of the waiting line.

In a repetitive focus factory,the number of channels available for the processing of a certain part would likely refer to

A college registrar's office requires you to first visit with one of three advisors and then with one of two financial professionals.This system is best described as

A concert hall,employing both ticket takers and ushers to seat patrons,behaves typically as a

The common measures of a queuing system's performance include

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour.What is the probability that the waiting line is empty?

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour.What is the average time a unit spends in the system and the average time a unit spends waiting?

You have seen that,in an M/D/1 problem,the average queue length is exactly one-half the average queue length of an otherwise identical M/M/1 problem.Are all other performance statistics one-half as large also? Explain.

Which of the following is an example of a finite arrival population?

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1.Units arrive at this system every 12 minutes on average.Service takes a constant 8 minutes.The average number in the system is approximately

Four of the most widely used waiting line models-M/M/1 or A,M/M/S or B,M/D/1 or C,and Limited population or D-all share three characteristics,which are

As the average service rate μ increases,the shape of the negative exponential distribution of service times

Operations and Productivity

Operations Strategy in a Global Environment

Project Management

Forecasting

Design of Goods and Services

Managing Quality

Statistical Process Control

Process Strategy and Sustainability

Capacity and Constraint Management

Location Strategies

Layout Strategies

Human Resources,job Design,and Work Measurement

Supply-Chain Management

Outsourcing As a Supply-Chain Strategy

Inventory Management

Aggregate Planning

Material Requirements Planning Mrpand Erp

Short-Term Scheduling

Jit and Lean Operations

Maintenance and Reliability

Decision-Making Tools

Linear Programming

Transportation Models

Learning Curves

Simulation

Filters