Design Lifecycles

Waterfall Model

Definiton

The waterfall is a way to break down project tasks into phases that happen in a straight line. Each phase depends on the results of the one before it and corresponds to a specialisation of tasks. Usually, for areas of engineering design.^

Methodology

6 Stages

Requirement Gathering stage

Design Stage

Built Stage

Test Stage

Maintenance stage

Pros and cons

pros

Each phase must be completed before the next.

Suitable for smaller projects with clear requirements

During the process of making software, any changes are made.

cons

Error can be fixed only during the phase

It is not good for complex projects where requirements change often.

The testing period comes quite late in the development process.

Spiral Model

Definiton

The spiral model is like incremental system development, but it puts more focus on risk analysis.

4 Phases

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Pros and Cons

Pros

Risk Handling

Good for large projects

Flexibility in Requirements

Customer Satisfaction

Cons

Complex

Expensive

Too much dependability on Risk Analysis

Difficulty in time management

The Star

The star life cycle approach can make it hard to manage time and keep track of progress, but it has the great advantage of being able to use user evaluation throughout the whole design process, adapting to the needs of the users as they are discovered and as they (inevitably) change.

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Iteractive User–Centred Model

Definiton

User–centered design (UCD) is
an iterative design process to
design focus on the users and
need to phase of the design
process

Process

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Usability Engineering Lifecycle

Definition

Usability engineering is a professional field that focuses on making systems easier to use. It uses theories from computer science and psychology to define problems that can happen when using such a system. Usability engineering is the process of testing designs with users or usability experts at different stages of the development process.

3 phase of UEL cyclic model

Requirements analysis

Design, testing, and development

Installation^

Diagram

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Scenario-Based System

interactive scenarios to support
active learning strategies such as
problem-based or case-based
learning
^

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