Analyzing system processes: Activity Diagram

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Asper School of Business
University of Manitoba
Systems Analysis & Design
Instructor: Bob Travica
Analyzing systems process:
Activity diagram
Updated 2014
Outline

Activity diagram concept

Elements of activity diagram

Reading activity diagrams

Process logic in activity diagram

Creating activity diagrams
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Activity Diagram (AD) concept

A diagram used for showing systems
requirements; results from process analysis

AD depicts:
 business processes (workflow) – manual &
automated (carried by a system)
 process logic – time order of process steps
(activities) & decision points
 actors (touch system), business event
sources (initiate actors to work)
AD resembles old flow charts and data flow

diagram
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AD components – Quote Process
Page 146
Start
Who/What performs
activity
*
Swimlane
(column)
Time
approximation
Activity,
Process step
Process
flow (control)
Decision point;
yes/no branching
Loop, one technique:
decision + flow back
End
* System=information system; sometimes called just “computer”
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AD components – Parallel Steps
Provide
Technical
Details
Synchronization Bars,
indicate parallel
processes
Parallel steps, run at the same time
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AD for Customer Ordering by Telephone –
more components
Page 227
(bit modified)
Decision shown
as Activity:
- N outflows
- Outflows
named
-
Loop
One method
Note:
1. loop bars
2. enter & exit
condition
Pasting
activities to
save space
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Process logic


Sequential (step 1, step 2, step 3…)
Conditional: If-Then (decision points: if
condition A, then step n); binary or N-ary
choices as outflows

Iteration/loop: Control back to a previous
step while a certain condition persists)


Slide 4, feedback from the “Change required?”
decision point
Slide 6, loop between bars For each item to
End of each
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What AD does not show?

Data passed between steps
(Data flow diagram shows it)

Objects
(But can be inferred; e.g., Customer, Order, Clerk)

User interface
(Clerk--System connection)
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How to create AD
1.
Identify activities (steps) of a process
2.
Identify who/what performs activities (process
steps)
3.
Draw swimlanes
4.
Identify decision points (if-then)
5.
Determine if a step is in loop (For each…,
or if-then loop)
6.
Determine if step is parallel with some other
7.
Identify order of activities, decision points
Continues…
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How to create AD
(cont.)
8.
Draw the start point of the process in the swimlane of
the first activity (step)
9.
Draw the oval of the first activity (step)
10.
Draw an arrow to the location of the second step
11.
Draw subsequent steps, while inserting decision
points and synchronization/loop bars where
appropriate
12.
Draw the end point after the last step.
You can tabulate these data (see next slide).
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How to create AD (cont.)
1
2
3
4
5
6
8
7
Step
ID
Process
Activity
or Decision
Who/What
Performs
Parallel
Activity
1
Request quote
Customer
No
No
2
Develop
requirement
notes
Salesperson
No
Yes
1
3
Decision: Help?
Salesperson
Yes
2
4
Salesperson
enters data
Salesperson
No
Yes
3
5
Check
requirements
Technical
Expert
No
Yes
3
6
Tech. expert
enters data
Technical
Expert
No
Yes
5
7
Calculate quote
System
No
Yes
4, 6
8
Review quote
Customer
No
Yes
7
9
Decision:
Changes?
Customer
No
Yes
8
Accept quote as
order
Customer
No
No
9
9
10
10
-
3510 Systems Analysis & Design * Bob Travica
Loop
Preceding
Step
-
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