Transcript Evaluation of Systems Analysis Methodologies in a Workflow

Evaluation of Systems Analysis
Methodologies in a Workflow Context
Fahad Al-Humaidan, Computing
Science, Newcastle University
Nick Rossiter, Computing and
Mathematics, Northumbria
University, England
[email protected]
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Methodologies
• Many in systems analysis e.g.
– SSADM (transaction-oriented relational db)
– UML (object-oriented environment)
• Initial effort on tangible ‘hard’ aspects
– Program code (functionality), data structures
(storage and retrieval)
• Omits resources (people, money and
equipment) and other ‘soft’ issues
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Soft Systems
• quality issues
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–
–
–
–
–
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identification of the problem
user involvement
organisational structure
goals and policies
employee job satisfaction
different points of view
employee’s values
system acceptability and usability.
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Approaches Evaluated
• OPM: The Organisation Process Modelling method
(Warboys, 1999)
• SSADM: The Structured Systems Analysis and Design
Method (SSADM, version 4, 1990 (Duncan, Rackley and
Walker, 1995)
• UML: The Unified Modelling Language (UML, version
1.3, 1998, Booch, 1999)
• Unified Process: The Unified Process method of 1999
(Rational Software Corporation, 2000)
• SSM: Soft Systems Methodology (SSM) (Checkland and
Scholes, 1990)
• Workflow (WFMS): The Workflow Management System
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(Jablonski and Bussler, 1996)
Evaluation Taxonomy: Developed to
cover both hard and soft aspects:
– hard aspects
1.
2.
3.
4.
Data
Events
Processes
Interfaces
– soft system aspects
5.
6.
7.
8.
9.
10.
11.
12.
13.
resources
quality
business issues
problem identification
user involvement
organisational structure, goals and policies
employee job satisfaction
different views
employee values
14. system acceptability and usability
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Comparison of Methodologies:
system elements 1-7
Method
Elements
OPM
SSADM
UML
UP
SSM
WFMS
1. Data
X
LDM
class
class./
database
X
workflow data
2. Events
CM
ELH
behaviour
behaviour
X
triggers
3. Processes
RAD
DFD
activity
activity
conceptual
process
4. Interfaces
X
Dialogue
design
class/component
sketch/
prototype
X
various
5. Resources
X
RC
stereotype
project
manager
root
info/
definition human
6. Quality
X
RC
prototypes
prototype
/ test
measures
rules
7. Business
issues
RAD
DFD/
ELH
activity
business
model
business
options
business 6
process
Comparison of Methodologies:
system elements 8-14
Method
Elements
OPM
SSADM
UML
UP
SSM
WFMS
8. Identify
problem
system
model
strategic
planning
strategic
planning
strategic
planning
Rich
Picture
9. User
involvement
gather/
validate
gather/
review
gather/
review
gather/
review
seek
encourconsensus age
10. Organ.
structure
process
analysis
strategic
planning
activity
model
business
model
Rich
Picture
11. Job
satisfaction
X
BSO
employee involve in involve in systemchoice
project
stages
delivered
12. Points of
view
Rich
Picture
RC
analyst
activity
integrated reconciled in CM
13. Values
use of
SSM
X
X
X
Analysis
Two
organisat.
populat.
14. Acceptability
taskstructure
various
user/prototyping
user/ tests user
involved
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solve
problems
enterprise
plan
enterprise
plan
multiple
paths
Merits of Approaches 1
• OPM
–
–
–
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Interactions between agents as they achieve their goals
Emphasis on agents in AI useful complementation
Deals with some hard and most of the soft
Soft coverage based on SSM to some extent
Lack of facilities for representing data structures
• SSADM
– Originally a hard system covering transactions in databases
– Deals with all hard aspects
– But only some of the soft aspects where uses some SSM features
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Merits of Approaches 2
• UML
– Expressive object-oriented modelling language
– Covers all hard aspects
– Weak on soft aspects
• UP
– Object-oriented development method based on UML
– Covers all hard aspects
– Stronger on soft aspects than UML but still not
comprehensive
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Merits of Approaches 3
• SSM
– weak on hard issues such as data structures, events,
interfaces
– strong on soft issues covering them all using Rich
Pictures in some cases
– soft issues of increasing importance in areas such as elearning
• WFMS
–
–
–
–
meets every criteria (hard and soft) to high extent
very wide-ranging
taxonomy was derived from WFMS so some bias
UML better in information system abstractions
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Conclusions
• Relatively strong on soft aspects:
– OPM, SSM
• Relatively strong on hard aspects:
– UML, UP
• Relatively comprehensive but lacking some
soft features -- SSADM -- or hard features - WFMS
• Future work: look at combining UML/WFMS
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