Vensim software work required for 3 students 3 copies
Lisa09
03.pdf
Dr. Daniel Xing Email: [email protected]
EBUS-504
Operations Modelling and Simulation
Lecture 2
Process mapping techniques + Witness functions
University of Liverpool
Management School,
UK
Objective
Learning objective from today
• Understand different types of process mapping tools
• Witness:
✓ Displays and element details
✓ Buffers, machines, parts and conveyors
✓ Input and output rules
✓ Labours and configuration for setup
✓ Route function
Building a Simulation Model
3. STRUCTURED
WALK-THROUGH
2. DATA AND
MODEL DEFINITION
1. PROBLEM
FORMULATION
6. VALIDATE
MODEL
5. PERFORM
PILOT RUNS
4. BUILD MODEL
AND VERIFY
10. DOCUMENT AND
IMPLEMENT RESULTS
9. ANALYSE OUTPUT
DATA
8. MAKE PRODUCTION
RUNS
7. DESIGN
EXPERIMENTS
Process Mapping Techniques • Graphical representation of how system components interact
• Describes the flow of information/material/jobs/documents etc.
• Tools for mapping
o Flowcharts
o Cross Functional Maps
o Gantt Charts
Process Mapping
ID Task Name Start End Duration
Oct 14 2001 Oct 21 2001
14 15 16 17 18 19 20 21 22 23 24 25 26 27
1 4d 4h19/10/200115/10/2001Task 1
2 1d22/10/200119/10/2001Task 2
3 2d 4h17/10/200115/10/2001Task 3
4 1d 4h22/10/200119/10/2001Task 4
5 3d 4h26/10/200123/10/2001Task 5
START Log Order
Receipt
Electronic
Record
Add to
queue
Select Next
in
Queue
Enough F
T
Assemble
Order New
Stock
Log Order
Completed
Dispatch
END
Check
Stock
Proc. 1
Process name
D e
p . B
D e
p C
D e
p . D
D e
p . A
Proc. 2 Check
Proc 4
Proc 5
Proc 7
Proc 6
(a)
(b)
Proc. 3
(shared)
(e)
(d)
(g)
(f)
(k)
(c)
(h)
(i)
(j)
Functional-based process
A1
A2 A3
B1 B2
B3 B4 C1
C2 C3
functional
Mixed Products
High utilisation of resources
Increased specialisation
Cross Functional Process Maps
Cross-functional charts are graphical maps that show how work is carried out in
an organisation. They show
Input/Output
Sequence
People, function or roles that perform each step
Process input output
Decision input
Option 1
Option 2
Cross Functional Process Maps
Proc. 1
Process name
D e
p . B
D e
p C
D e
p . D
D e
p . A
Proc. 2 Check
Proc 4
Proc 5
Proc 7
Proc 6
(a)
(b)
Proc. 3
(shared)
(e)
(d)
(g)
(f)
(k)
(c)
(h)
(i)
(j)
Exercise Applying to study at UoL
A student needs firstly to fill an application post with support documents. The filled
information will be passed to the admission office for automating a temporary student
ID. Once the ID is created, the applicant will be notified immediately and profile of this
ID will be sent to the associated course director for an application assessment. If the
course director rejects this student, a rejection letter will be created and it will also be
sent to the faculty office to update computer record. If this student is accepted, a copy
application will be generated for further consideration if all academic conditions are
met. If so, the course director will suggest an unconditional offer to the faculty office to
update the computer record. If not, the course director needs to specify what
conditions are further needed and this will also result in an update of computer record
in the faculty office. Based on the computer record, the faculty office will decide
whether a conditional offer is needed for the applicant. If so, a conditional offer is
generated and it will also be replied to the student for further instruction. If not, an
unconditional offer is written and the applicant will be instructed to prepare for
enrolment.
Example: Applying To Study at Liverpool University
Applying To study at Liverpool University
U A
O C
o u
rs e
D ir
F a
c u
lt y
S tu
d e
n t Fill Application
Post with
support
Documents
enter information in
computer & generate ID
Write back to
student with ID
Assess
Appication Accept
Write Rejection
letter
Copy
Application
Specify
Conditions
Satisfy
Cond.
Recommend
Unconditional
offer
Write
Unconditional
Offer Letter
Update
Computer
record
Update
Computer
record
Inform
Faculty office
Prepare to
enroll
Conditional
Write
conditional
Offer Letter
Meet
Conditions
Y
N N
Y
Y
N
Product-oriented Processes
product oriented
A1 B3 C2
A1 B4 C3
Product A
Product B
Reduction in
•Processing times (dedicated processes)
•Changeover
•WIP
•Transportation
GANTT Chart: Product-Based
Flow of parts in a cell or department with
duration of each activity
Example
Assume Parts A and B arrive to a cell with
a number of process M1,M2,M3
Each part has the following routes
B 1 B A
M 1 A B A
B 2 B
M 2 A B A
B 3 B
M 3 A B
Bout A B
Time 0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
8
0
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
2
0
2
1
2
2
2
3
2
4
2
5
2
6
2
7
2
8
M1
M2
M3B3
B2
B1
GANTT Chart: Product-Based
A M1 M2 B3 M3 M1 M2
B B1 M1 M2 B1 M1
C M2 M3 M2 M3
Time 0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
8
0
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
2
0
2
1
2
2
2
3
2
4
2
5
2
6
2
7
2
8
• Variation on GANTT charts using Product as the
base line
• Example (Manufacturing Cell):
• A visits M1,M2,M3
• B visits M1,M2
• C visits M2,M3
• M1 and M2 processing time (5)
• M3 processing time (8)
M1
M2
M3B3
B2
B1
Example and exercise
M1
3mins
M2
5mins
Pa every
6mins
M1
3mins
M2
5mins
Pa every
6mins
Pb every
4mins
B1
M3
3mins B2
M4
6mins B3
Witness introduction part 2
1: Style Graphic representation for any entities in Witness that is supposed to have an
animation movement (e.g. parts, labours). It can be description only or an Icon.
2: Icon (Monochrome) Graphic representation for any entities in Witness in statically. It can be
customised with Editor function and a monochrome image can represent entity
states (use keys to see the meaning of different colours) later.
3: Part queues and labour queues
Presenting the location of your expected queues, built-up direction,
count and queue animation.
✓ Display types – displays can be created as many as you like for
one entity
Witness introduction part 2
✓ Based on the example from Witness Intro-1, create a state light
and a counter for your buffer
Witness introduction part 2
✓ Based on the example from Witness Intro-1, create a state light
and a counter for your buffer
You can
change the
font of your
counter
display here
Witness introduction part 2
✓ Based on the example from Witness Intro-1, create a state light
and a counter for your buffer
Why do we
have two part
queues?
Witness introduction part 2
1: A conveyor has length, movement time and capacity ▪ Length can be measured by part dimention.
▪ Indexed time: it specifies the amount of time it takes a part to move
through one part length of the conveyor.
2. Input and output rules (with position)
3. Use Shift and Control key to break a conveyor and bend a
conveyor.
✓ Conveyors
Witness introduction part 2
1:Pull from multiple places (pull from {position 1}, {position 2}, …)
• Flexible inputs
• Cannot define sequence
• Pull from next position if the former position is empty.
2. Sequence rule (sequence /failure_option location1, {location2}
{location3...}).
▪ Both flexible and strict sequence
▪ Quantity for each pull can be specified.
✓ Input from / output to multiple places
Witness introduction part 2
1:Push to multiple places (push to {position 1}, {position 2}, …)
• Easy manage but not good for overall utilisation
performance.
• Differentiate queues
2. Least/most parts (least/most parts|free location1 {, location2 ...})
▪ Balanced queue
▪ Not consider different queue capacities
✓ Input from / output to multiple places
Witness introduction part 2
✓ Route function
Witness introduction part 2
✓ Route function
Witness introduction part 2
✓ Route function
Witness introduction part 2
✓ Route function
Witness introduction part 2
✓ Route function
Witness introduction part 2
✓ Route function
Witness introduction part 2
✓ Route function
Use Route tab to add stages
Define the details for each stage
Witness introduction part 2
✓ Route function
Dr. Daniel Xing Email: [email protected]
EBUS-504
Operations Modelling and Simulation
Lecture 2
Process mapping techniques + Witness functions
University of Liverpool
Management School,
UK
