Conceptual modelling :: 3 of 3

< previous | next >

Conceptual modelling illustrated
Remember, conceptual models are not diagrams or specifications, because they are essentially mental representations that live in people's heads. Pictures and words can however be used to describe these (abstract, slippery, inside-the-head) conceptual models. An argument in favour of a significant carbon tax is a good example of a conceptual model.

Written version of the conceptual model

There are a number of objects and relationships in this conceptual model:

• Objects
• Fuel
• Environment
• Taxes
• Health
• Cost

And there are certain kinds of relationship, including:

• Time
• Quality (i.e. better or worse)
• Change (i.e. increases and decreases)
• Use or consumption

At present the cost of fossil fuel combustion does not include the direct health costs associated with respiratory ailments linked to photochemical smog in urban areas or the costs associated with other environmental problems such as acid rain or possible long-term climate changes.

A significant carbon tax will better reflect the true cost of fossil fuels to the citizens; pay at the pump now or pay taxes later to support increased demands on the health care system.

Such a carbon tax will increase the cost of fossil fuel energy sources making alternative energy sources like solar, wind, hydrogen fuel cells, and tidal more economically competitive.

This will help shift our economy from its near exclusive use of fossil fuels towards cleaner more efficient fuels, which will ultimate cut global carbon emissions.

The reduced carbon emissions will help curtail the build-up of carbon dioxide in the atmosphere. In addition, other harmful by-products of fossil fuel combustion, particularly in urban areas, will be reduced.

To create a diagram of our conceptual model, we start by identifying the components in the model.

We then create tokens for each, as here: light grey ellipses for components, and dark grey boxes for relationships.

Note that these tokens may be at entirely the wrong level of detail, either too specific or too general. For example, a user may have a single component for the concatenation of "pollution" and "climate change". We can only judge this by validating our diagram against the real model(s).

In a user's conceptual model, some components may be grouped together to form more complex components.

We can use concatenation of tokens (i.e. physically putting things next to each other) to represent this in our diagramming, as below:

< previous | next >