Transcript Project Life Cycles

Project Life Cycles
System development life cycle
• Waterfall model
• Spiral model
• Whirlpool model
• Rugby model
• OMG model
Waterfall model
Project proposal report
project
definition
Functional
specifications
Feasibility report
system
study
design
design specifications
program specifications
code
programming
system performance
tests
Installation
- intermediate reports
- go/nogo intervals
Post Implementation
audit , feed-back
Boehm’s Spiral Model
progress
through
steps
determine
objectives,
alternatives
constraints
Risk
Analysis
evaluate alternatives
identify , resolve risks
Risk
Analysis
requirements plan
life cycle plan
integration
tests and plan
Risk
operational
Analysis
prototype 2
prototype
prototype 1
simulation
models
Benchmarks
concept of
operation
Software
design
Design
detailed design
validation and
verification
coding
Plan
next phases
Prototype based
integration
tests
implementation
Whirlpool model
project
definition
Project proposal report
system
study
Functional specifications
Feasibility report
design
design specifications
program specifications
code
programming
system performance
tests
Installation
Post Implementation
audit , feed-back
After each phase a quick review of the previous phases is made
OO-life cycle
With the increasing complexity of the systems,
the structured techniques suffer from two
illusions:
 The analyst knows everything and
understands the problem completely
before implementation starts
 The users read the system analysis report
and approve it
OMG-model (Object Management Group )
Facts:
 System requirements are not fully known at the start
 knowledge of the system grows during development
 better develop a system incrementally
 start with some core functions
analysis
object
modelling
design
construction
coordination and reuse
full
system
definition
OMG Project Management
 Iterative style
develop a series of solutions to a problem ,
each of them closer to satisfying the requirements
( also called : evolutionary development )
 Incremental style
Builds system functionality a little at a time.
The results are not entire solutions.
Matthew Pittman proposes iterative analysis and design
combined with incremental development
Problem is managing the reuse (by design , not by accident)
How can such a project be estimated , tracked , controlled
The Waterfall Model
Waterfall model
Project proposal report
project
definition
Functional
specifications
Feasibility report
system
study
design
design specifications
program specifications
code
programming
system performance
tests
Installation
- intermediate reports
- go/nogo intervals
Post Implementation
audit , feed-back
Project definition
What do we want to accomplish ?
- solve a new problem
- incorporate new requirements
- improve existing system
Is a new system the best solution ?
Who will be involved ?
Organizational problem
System study : functional specs
Objective:
What is the problem ?
Responsibility:
The user
Execution:
1. Activities:
Top-down technique
just a few sentences
2. Logical operations ( processes): for each activity
3. Details and definitions: rules, actions, controls , forms
4. Detail information:
object, units, begin and end, classes, names
System study : functional specs 2
The problem definition report includes:
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For the input:
 form
 point of time and frequency
 origin
 responsibility
For the output:
 type and layout
 point of time and frequency
 destination
 usage
Furthermore:
 reasons for realization
 financial advantages
 constraints and borders of the system
System study : The feasibility study
Responsibility from this phase on in the ICT-department
 study of the existing system
 borders of the new system
 links with other systems
 study of different solutions
 division in subsystems
 applicability of packages
 estimation of personnel requirements
 cost-benefit analysis
The report allows the steering committee to: - fix timings
- final decision
Design : general
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What must be done to solve the problem?
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function analysis
inventory of the data elements
data dictionary
logical model of the system ( data analysis )
major algorithms
compose the working groups
planning per department
Design : Detailed
- interfaces with other systems
- controls and checking
- privacy and security aspects
- hardware specifications
- job flow design
- Physical database design
- high-level program design
Detailed system and design specification
Programming and Implementation
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Program design
diagrams
code
tests
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documentation
data conversion
procedure development
user training
- Program specifications
- Code
Installation
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Installation of the hardware
Install security procedures
Tests in operational environment
Training operations department
Take-over in user department and EDPdepartment
Operational
- User documentation
- Operations documentation
Post-implementation
AUDIT
 compare actual system with projected budget and
timing
 evaluate actual operation cost
 evaluate user satisfaction
 evaluate security
MAINTENANCE
 establish hardware maintenance procedures
 test security plan
 establish change management procedures