Exam 3

Question 1

Why do Queues form?

Answer 1

Queues form when the Capacity rate is smaller than the Demand Rate

Question 2

Queues form from?

Answer 2

Variability (Customer Arrival and Service Time)

Question 3

What is the implication of PK Formula?

Answer 3

Time in queue increases in Utilization Rate and Varivility of both arrival time and service time

Question 4

#
                           /
OOO--->#--->OO-- #
                           \   #
How many phases? How many servers in second phase?

Answer 4

2 phases

3 servers in phase 2

Question 5

Service happens only when

Answer 5

Capacity and demand are available at the same time

Question 6

What is the benefit of serving the Shortest processing time first?

Answer 6

Reduces the average waiting time

Question 7

Which type of queue would use a first come first serve approach?

Answer 7

Single Queue

Question 8

___/____/____

Answer 8

Distribution of time between arrivals (M,D)
Distribution of service time (M,D)
Number of servers (1,c)

Question 9

Difference between M and D

Answer 9

M= Random, exponentially distributed
D= Deterministic

Question 10

Difference between 1 and C

Answer 10

1= Single Server
c= Multiple servers

Question 11

The key feature of of Erlang Loss Model

Answer 11

Customer leaves if system is full, there is no queue

Question 12

Where can Erlang Loss model be applied

Answer 12

DVD rental- there is no wait for the movie if the movie is not there

Question 13

Throughput Rate assuming no demand loss

Answer 13

Throughput rate= minimum( Demand rate, Capacity Rate)

Question 14

Throughput rate assuming demand loss:

Answer 14

Throughput Rate< minimum (demand rate, capacity rate)

Question 15

In a general waiting system, how do you reduce throughput loss?

Answer 15

Create buffer to keep customers

Decrease waiting time to avoid customer balking

Question 16

What is customer balking

Answer 16

customers leaving after they join the queue due to long waiting time

Question 17

Who determines tolerance limits?

Answer 17

Customers, Designers

Question 18

Who determines control limits?

Answer 18

Producers, Quality Controllers

Question 19

What happens beyond tolerance limits?

Answer 19

Defects

Question 20

What happens beyond Control Limits?

Answer 20

Actions need to be taken

Question 21

When control limits are violated but tolerance limits are satisfied….

Answer 21

Need to check system

Question 22

Pull System

Answer 22

The production dynamic is initiated from demand part (make to order). Information flows from downstream to upstream. Baked Cookies

Question 23

Push System

Answer 23

The upstream station or suppliers initiate the production schedule (make to stock), information flows from upstream to downstream. MacBook’s

Question 24

Three levels of customer fulfillment:

Answer 24

Customer Service
Customer Satisfaction
Customer Success

Question 25

Customer Service

Answer 25

Fulfill basic service requirements

Question 26

Customer satisfaction

Answer 26

Meet or exceed customer expectations

Question 27

Customer Success

Answer 27

Assist customers in meeting their objectives, long-term relationship

Question 28

Basic Customer Service includes:

Answer 28

Product Availabilty Lead-Time Performance Service Reliability

Question 29

Product Availability: Unit Fill Rate

Answer 29

% of ordered units delivered= Units Delivered/Units Ordered

Question 30

Product Availability: Order Fill Rate

Answer 30

% of orders shipped complete= Orders delivered/ Orders Demand

Question 31

Lead Time

Answer 31

The time between start and end of an activity

Question 32

Service Reliabilty

Answer 32

No Errors: Damage free, right quantity, right time | Provide critical information of inventory and order status

Question 33

What kind of product can be outsourced?

Answer 33

The product NOT in the area of core competencies | Mature products with standard processes

Question 34

Tradeoff related to too few suppliers

Answer 34

Risk(shortage, lack of competition)

Question 35

Tradeoff related to too many suppliers

Answer 35

Complexity

Question 36

Which supplier do you chose in the weighted point model

Answer 36

Supplier with highest score

Question 37

Select supplier by online auction when

Answer 37

Price is the most important factor

Question 38

Select supplier by negotiation when

Answer 38

Requirement is complicated, supplier involved, complex start up (Divorce)

Question 39

How to manage the relationship with suppliers?

Answer 39

Share information | Performance monitoring and improvement

Question 40

Throughput Rate

Answer 40

How many customers served in a given amount of time

Question 41

r=

Answer 41

Arrival rate/Service Rate

Question 42

Throughput=

Answer 42

Arrival Rate(1-probability system is full)

Question 43

Average Waiting Time=

Answer 43

Average Length of Queue/Arrival Rate (Little's Law)

Question 44

Score=

Answer 44

Weight X Rating