1.4 modelling in software development

Modelling in software development

• 
• A model is an abstract representation of a concept, a specification, a design or system form a particular point of view of either the user or the developer.
• In general it is a simplification that is used to understand an aspect of the system in general.

Models illustrate points of view

• To understand the architecture of a software system you will need a number of complementary and related views.
• If the main influence is the users, a view to express their requirements is essential.
• During the process you will be interested in different aspects or views at different times, and you will construct models to suit these aspects.
• There should not put too much detail into a model as it will be a distraction
• There are two types of model;
• structural (or static) models - describe objects in the real world or software system and their relationships to other objects.
• behaviour (dynamic) models - describe the behaviour in the real world or software system over time.

The Unified Process(UP)

Activities and artifacts in development

Summary

• This section considered the role of modelling in the development of a good software system:
• A model is an abstract representation of a concept, a specification, a design or a system from a particular point of view. Generally it is simplification used to understand an aspect of a system.
• A standard modelling language allows people to communicate more effectively.
• The Unified Modeling language (UML) is a useful standard because it is easy to use, expressive, unambiguous and widely used. A variety of tools support UML
• During software development there can be a number of models from various viewpoints, they must be consistent and not contradict each other.
• The UP is a popular iterative and incremental development process. It defines a series of timeboxed iterations and promotes a set of best practices that are high-risk driven, user centred and architecture focused. It is possible to take an agile approach to the UP as many of its practices are also supported by agile developers. The process followed in this module will be loosely based on the UP and we will be also discussing agile alternatives in parallel.