1
Modeling and Simulating Business Processes
Chapter 8
Business Process Modeling, Simulation and Design
2
Simulating Business Processes
We recommend presenting this chapter by running Extend 6.0 directly, and interactively show how the program works.
However, for your convenience, we have attached a selection of the figures/screenshots from Chapter 8 of the book as the basis for an in class presentation without access to a computer with Extend installed.
NOTE:
3
Import block dialog showing and exponential inter-arrival times with mean of 6 minutes
Generating Items
4
Input Data block used to change the first parameter of the inter-arrival time distribution in the Import block
2 V1 A P
t y
Generating Items
5
Input Data block dialog for dry cleaner example
Generating Items
6
Program block (and dialog window) connected to a Stack block
Generating Items
7
Selection of a priority queue in the Queue tab of a Stack block
Prioritizing Items
8
Model of a single server with a queue, where customers balk if the line reaches a specified number of customers
Balking
9
Dialog window of the Decision(2) block
Balking
10
Model of a single server with a queue, where customers hang up after being on hold for specified amount of time
1 2 3
Rand
2 V1 A P
L w p
pR
0
C
# u
D
1
#
7
#
23
Incoming
calls Calls on holdAnswered
calls
Lost calls
Helping
customers
Generating
call time
Reneging
11
Stack block to simulate a reneging queue with reneging time of 5 minutes
Reneging
12
Admissions process with a priority queue that allows patients to go in front of the line after filling out additional forms
Priority Queues
13
Dialog window of the Stack block
Priority Queues
14
Example of probabilistic routing of an incoming job
Path 1
Path 2
Path 3
0.20
0.30
0.50
Incoming job
Routing - Multiple Paths
15
Illustration of probabilistic routing with Extend
?
Decision(5)
2 V1 A P
Import
1 2 3
Rand
Random Number
#
21
Path 1
#
29
Path 2
#
50
Path 3
Generate jobs
Probabilistic
decision
0.20
0.30
0.50
Multiple Paths
16
Illustration of tactical routing with customers choosing the shortest line
2 V1 A P
?
L w p
pR
A1-3
A1-3
S
DS
u
1 2 3
Rand
#
245
MaxCon
MinCon
L w p
pR
A1-3
A1-3
S
DS
u
1 2 3
Rand
#
211
L w p
pR
A1-3
A1-3
S
DS
u
1 2 3
Rand
#
169
L1
L2
L3
L1L2L3
Multiple Paths
17
Prepare invoice
Assemble order
Receive order Ship order
Parallel activities in an order fulfillment process
Routing – Parallel Paths
18
Operation, Reverse block and dialog window
Parallel Paths
19
Operation block that batches two items
Parallel Paths
20
RQ1-Q32 V1 A P
A1-3
A1-3
S
DS
u
Receiving Order
A1-3
A1-3
S
DS
u
Prepare Invoice
A1-3
A1-3
S
DS
u
Assemble Order
A1-3
A1-3
S
DS
u
Ship Order
#
Extend model of the order fulfillment process
Parallel Paths
21
Slider control
A1-3
A1-3
S
DS
u20
10
17
Processing Time
22
Input Data block to model variable processing time
Processing Time
23
Processing time based on the value of the “ProcTime” attribute
Processing Time
24
Batch block and dialog window
Batching
25
Preserving uniqueness when batching a purchase order and an agent
Batching
26
Unbatching items with an Unbatch block
Batching
27
Model that batches patients and nurses
Batching – Resources
28
Cost tab of the Import block
Activity-based Costing
29
Model to accumulate cost per unpacked crate
Activity-based Costing
30
Dialog of the Cost by Item block
Activity-based Costing
31
Two operations in series with a Timer block to measure cycle time
Cycle Time Analysis
32
Histogram of cycle times and average cycle time vs. simulation time
0 150 300 450 6000
1.5
3
4.5
6
Simulation Time
MinutesAvg. Cycle Time vs. Simulation Time
Avg. Cycle Time Red Green Black
0 4.3 8.6 12.9 17.20
43.75
87.5
131.25
175
Cycle times
CountHistogram
DelayTime Data DataData
Cycle Time Analysis
33
5
1
3.6 1 2 3
Rand
Slider control to set the mean value of an Exponential distribution
Model Enhancements
34
Meter connected to the utilization output of Labor Pool block
Model Enhancements
35
Clone layer tool
Model Enhancements
36
Documented software support process
Software
Engineer
Incoming
calls
Real-time
response
Software
Engineer
Incominge-mails Problems
resolved
Case: Software Support
37
Simulation model of actual process
Case: Software Support
38
Simulation model of documented process
Case: Software Support
39
Admissions
RegistrationDesk
Lab
WaitingRoomTypes 2 and 3
TimeU(2,5)
Type 1 TimeU(3,8)
Floors
Schematic representation of the hospital admissions process
Case: Hospital Admissions
40
Extend model of the current admissions process
Arrivals
Reg and Lab
Patients type 2 and 3
go to registration and
lab tests
Patients arrive
every 15 minutes
Type 3 patients
Admitting officers
help patients
Type 2 patients
Rooms
Orderlies accompany
patients to their rooms
MD
sensorTimer
#
33
Change priority from
type 2 to 1.5
Types 1 and 2
Total number of
patients served
Arriving patients and
type 2 patients
returning from the lab
are merged
Type 2 patiens
walk back to
admissions
Update
Activity
Stats
P
Set P
Admissions
C
# u
D
Walk back
Case: Hospital Admissions
41
2 V1 A P
T
Sys
Var
Current time
1 2 3
Rand
Before 10 AM
1 2 3
Rand
After 10 AM
Get P
P
Con1OutCon1OutY
N?
A
Set A
#
2
Patients arriving after
4 PM are sent to the
outpatient desk
Sys
Var
Current time
Arrivals block from the admissions model
Case: Hospital Admissions
42
Admissions block from the admissions model
C
# u
D
Type 1
L w p
pR
QueueGet P
P
u #
Con1InCon1In
Con2OutCon2Out
Con3OutCon3Out
demand
a
b
c
1 2 3
Rand
C
# u
D
Type 2
Patients wait for an
admissions officer
If patient is type 2 or
3, go to the lab,
otherwise go to the
rooms
1 2 3
Rand
C
# u
D
Type 3
1 2 3
Rand
Get P
P
Pool of admitting
officers
demand
a b cabc
Case: Hospital Admissions
43
Registration and Lab block from the admissions model
C
# u
D
Registration
L w p
pRC
# u
D
Lab tests
L w p
pR
Waiting room
Y
N?
Get P
P
Con1InCon1In
Con2OutCon2Out
Con3OutCon3Out
1 2 3
Rand
1 2 3
Rand
Patients form a line at
the registration desk Patients wait for a lab
technicianType 3 patients
leave the process
Type 2 patients
return to the
admissions desk
Case: Hospital Admissions
44
Rooms block from the admissions model
C
# u
D
Walk to roomdemand
a b cabc
Pool of
orderlies C
# u
D
Wait for papers
C
# u
D
Walk back
demand
a
b
c
Con1OutCon1Out
Con3InCon3In
select
b?
a
0.8
0.2
u #
Orderlies and
patients walk to
the rooms
Orderiles and
patients are
unbatched
1 2 3
Rand
Orderlies and
patients are
batched
Orderlies walk back
to admissions
Case: Hospital Admissions
45
Histogram of cycle times for type 1 patients
0
10
20
30
40
50
60
70
80
90
100
20 30 40 50 60 70 80 More
Cycle time
Fre
quen
cy
.00%
20.00%
40.00%
60.00%
80.00%
100.00%
Case: Hospital Admissions
46
Extend model of the redesigned admissions process
AdmissionsArrivals
Lab tests
Patients type 2 and 3
go to lab tests
Patients arrive
every 15 minutes
Type 3 patients
leave
Admitting officers
help patients
Type 2 patients
Rooms
Orderlies accompany
patients to their rooms
MD
sensorTimer
#
36
Types 1 and 2
Total number of
patients served
Type 1 and 2 patients
are merged
Type 2 patiens
walk to wait for
an orderlyC
# u
D
Walk back
Case: Hospital Admissions
47
A
B C
D E
F G
Type I
TypesII & III
Measuring cycle times of different types of jobs
Exercise 1
48
A1 B1
A2 B2
A3 B3
Type 1
C1
C2
C3
Type 2
Type 3
Investigating the effect of pooling resources
Exercise 2
49
Review &D istribu tion
U nderwriting RatingPolicy
Writing
Assessing process performance
Exercise 4
50
A
B
C E
D
F
0.8
0.2
Priority queues
Exercise 7
51
A
B C
D E F G H
I J
0.2
0.2
0.8
0.5
0.5
Flowchart for Exercise 8
Exercise 8
52
Flowchart for the X-ray process
1 2 3 4 5 6 7
10
11
128 9
25%
Project: X-ray Process
53
2
1
3
4 5
Storage of inboundmaterial
Parallel operations(Workstations 1-3)
Assembly(Workstation 4)
Painting(Workstation 5) Inspection
Rework
Flowchart of the production processfor the Assembly Factory
Project: An Assembly Factory