Models of Situations

A computer model of a system is a program and data which behaves like the real thing, e.g. a driving simulation, a graph of business profits, a robot arm.

A model: may copy only part of the actual

system; is determined by rules usually built into

the program; can be used to forecast what will

happen in the real world.

A model can be used in order to: avoid danger; save money; save time; help make difficult decisions;

A computer model may run at the same rate, faster or slower than the real system.

Many computer models have a mathematical basis with:

real quantities represented by variables in the program;

rules for the models behaviour contained in formulae;

In practise computer models can be produced using:

spreadsheets; computer graphics, including charts; simulation programs virtual reality systems; expert systems;

The stages in producing a model are: analyse the problem; design the model; produce the model;

A computer simulation of a system is a program which models the system.

A virtual reality simulation is a simulation which appears real: the user feels a part of the simulation. the simulation may be experienced through all senses.

A expert system is a computer program which simulates the knowledge and experience of a human expert. A expert system consists of: a knowledge base of rules and facts; a program to work out a solution of the user's problem.