topic 6 - waiting lines

Question 1

What is a service facility

Answer 1

A facility having a person, a team, machine(s), or all to perform the service for the customers

Question 2

How big can the customer population (input) be?

Answer 2

Both FINITE or INFINITE

Question 3

What are all the arrival characteristics?

Answer 3

• Average Arrival Rate
• Average Time between arrivals
• Probability of N arrivals in a period

Question 4

What letter represents MEAN SERVICE RATE per server

Answer 4

μ

Question 5

What is the structure of a waiting-line

Answer 5

1. INPUT (customer population), that generates potential customers
2. WAITING LINE of customers
3. SERVICE FACILITY, having a person, a team, machine(s), or all to perform the service for the customers
4. PRIORITY RULE, which selects the next customer to be served by the service facility
5. SERVED CUSTOMERS, those who have received the service

Question 6

Example of a single-server, multi-phase system?

Answer 6

McDonald’s dual-window drive-through

Question 7

Example off a multi-server, single-phase system?

Answer 7

Bank and post office service windows

Question 8

What are served customers?

Answer 8

They are the customers who have received the service

Question 9

What is the letter for representing AVERAGE ARRIVAL time?

Answer 9

λ

Question 10

Why do waiting lines form?

Answer 10

Due to a temporary imbalance between the demand for a service and the capacity of the system to provide the service

Question 11

Example of a multi-server, multi-phase system?

Answer 11

Airport security

Question 12

What is an example of a waiting line?

Answer 12

• A bank office
• Supermarket checkouts
• Dentist
• McDonald’s dual-window drive-through

Question 13

How do you calculate AVERAGE TIME BETWEEN PERIODS

Answer 13

1 / λ

Question 14

What is a waiting line?

Answer 14

A line that has one or more customers waiting for a service

Question 15

What is the difference between the structure of a waiting-line and a service system?

Answer 15

The service system structure DOES NOT have an input (step 1) nor served customers (step 5)

Question 16

What is input?

Answer 16

Something that generates potential customers

Question 17

What are the different type of service systems?

Answer 17

• *SINGLE-server, SINGLE-phase** system (dentist’s office)
• *SINGLE-server, MULTI-phase** system (McDonald’s dual-window drive-through)
• *MULTI-server, SINGLE-phase** system (Bank and post office service windows)
• *MULTI-server, MULTI-phase** system (Airport security)

Question 18

What are all SERVICE characteristics?

Answer 18

1. Mean service rate per server
2. Mean Service Time
3. Probability of service time

Question 19

Example of a single-server, single-phase system

Answer 19

A family dentist’s office

Question 20

How does the Earliest Due Date (EDD) work

Answer 20

It serves the customer with the earliest promised date first (like a restaurant reservation or doctor’s appointment)

Question 21

How does priority rule work?

Answer 21

Is selects which customer goes first

Question 22

What is the structure of a service system?

Answer 22

2. WAITING LINE of customers
3. SERVICE FACILITY, having a person, a team, machine(s), or all to perform the service for the customers
4. PRIORITY RULE, which selects the next customer to be served by the service facility

Question 23

Calculate MEAN SERVICE TIME

Answer 23

1 / μ

Question 24

How does PREEMPTIVE DISCIPLINE work?

Answer 24

Rules that give priority to a customer (like the ER for hospitalities)

RULES DEPEND on service facility

Question 25

What are the different types priority rules?

Answer 25

FCFS Earliest Due Date (EDD) Shortest Processing Time (SPT) Preemptive Discipline

Question 26

What are the 2 different type of waiting lines

Answer 26

1. Single Line 2. Multiple Lines

Question 27

How does the SPT work?

Answer 27

The customer that takes the least amount of processing time goes first