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# Modelling

Modelling

Modelling

Modelling : summing up

Modelling  (^)

Modelling is building  Models  for the representation of modules, i. e. the entities of a System.

Stages

Modelling requires one to:

• Decompose the system into its basic entities

• Identify the essential/relevant entities and linkages

• Recompose a simplified/selected version of the system with its essential/relevant entities and linkages (i.e. the model)

Models  (^)

Models  (^)

Definition

A Model is a selected simplified representation of the essential or relevant entities (modules) of some specific reality and their characteristics (fields, factors, features).

Classification

The basic types of Models are:

• Iconic

• Analogue

• Symbolic

Iconic  (^)

Definition

An Iconic Model is a look-alike representation of some specific entity (e.g. a house)

Classification

Iconic Models can be represented in:

• Two Dimensions : e.g. photos, drawings, etc.

• Three Dimensions : e.g. scale model

Remark

A scale model can be a:

• reduction (scaled down, e.g. the model of a building)

• reproduction (same scale, e.g. copy model, prototype or working model)

• enlargement (scaled up, e.g. the model of an atom)

of some specific entity

Analogue  (^)

Definition

An Analogue Model is the representation of entities of a system by analogue entities pertaining to the model (e.g. through diagrams).

Classification

An Analogue Model can be built through:

• Two Dimensional Visualization : Charts, Graphs, Diagrams

(e.g. the colour coding of a geographical chart for representing different altitudes)

• Three Dimensional Visualization : Analogue Devices

(e.g. the flow of water in pipes to represent the flow of electricity in wires or the flow of resources in an economic system)

Symbolic  (^)

Definition

A Symbolic Model is the representation of entities of a system through symbols.

Symbols can be:

• mathematical

• logical

Remark

A Symbolic Model is used whenever the reality is:

• too complex or too abstract to be portrayed through an iconic or analogue model

• the factors of the system (variables) can be represented by symbols that can be manipulated in a meaningful and fruitful way

Modelling : summing up  (^)

Modelling is the building of Models.

Models can be:

• Iconic

• Analogue

• Symbolic

The use of Models allows for:

• Exploration

• Explanation

• Extrapolation

Extrapolation is achieved through manipulation of Models with a view to Simulating.