What is a Model and what are the characteristics of an useful Model ?

What is a model ?

• A model is a simplification of reality
• Provides the blue-prints of a system
• Different models describe the same system from different perspectives

Why engineers build models ?

It’s all about understanding complex systems.

• A model is a reduced version of a system that emphasizes the essential and obscures the irrelevant abstraction.
• Essentially the approach of “divide-and-conquer”.
• Attack a hard problem by dividing it into a series of smaller problems.

To detect errors and omissions in requirements and solutions before committing resources to full-fledged implementation

To communicate with stakeholders

• Clients, users, implementers, testers, documenters, etc.

To guide the implementation

• For software systems, this has special significance

Characteristics of useful models

Abstract

• Emphasize important aspects while hiding/removing irrelevant ones

Understandable

• Expressed in a form that is readily understood by observers

Accurate

• Faithfully represents the modeled system

Predictive

• Can be used to derive correct conclusions about the modeled system

Inexpensive

• Much cheaper to construct and study than the modeled system