Project Life Cycles. System development life cycle Waterfall model Spiral model Whirlpool model...

Project Life Cycles

System development life cycle

• Waterfall model

• Spiral model

• Whirlpool model

• Rugby model

• OMG model

Waterfall model

projectdefinition

system study

design

programming

Installation

Post Imple-mentation

Project proposal report

Functional specifications

Feasibility report

design specifications

program specificationscode

system performance tests

audit , feed-back- intermediate reports

- go/nogo intervals

Boehm’s Spiral Model

prototype 1prototype 2

operationalprototype

RiskAnalysis

RiskAnalysis

RiskAnalysis

determine objectives,alternativesconstraints

evaluate alternativesidentify , resolve risks

simulationmodels Benchmarksrequirements plan

life cycle plan concept ofoperation

Software design

Designvalidation and verification

integrationtests and plan

detailed design

coding

integration tests

implementation

progressthroughsteps

Plannext phases

Prototype based

Whirlpool model

projectdefinition

system study

design

programming

Installation

Post Imple-mentation

Project proposal report

Functional specifications

Feasibility report

design specifications

program specifications

code

system performance tests

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 startknowledge of the system grows during development

better develop a system incrementallystart with some core functions

object modelling

analysis

design

construction

fullsystemdefinition

coordination and reuse

OMG Project Management

Iterative styledevelop a series of solutions to a problem ,

each of them closer to satisfying the requirements

( also called : evolutionary development )

Incremental styleBuilds 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

projectdefinition

system study

design

programming

Installation

Post Imple-mentation

Project proposal report

Functional specifications

Feasibility report

design specifications

program specificationscode

system performance tests

audit , feed-back- intermediate reports

- go/nogo intervals

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: Top-down technique

1. Activities: 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: 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

What must be done to solve the problem?

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

Program designdiagramscodetests

documentation data conversion procedure development user training

- Program specifications- Code

- Program specifications- Code

- User documentation

- Operations documentation

- User documentation

- Operations documentation

Installation

Installation of the hardware Install security procedures Tests in operational environment Training operations department Take-over in user department and EDP-

department Operational

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