New Mexico Computer Science For All

Abstraction in Modeling and Simulation

Maureen Psaila-Dombrowski

Abstraction•Abstraction is Simplification

•Why?▫“Real world” problems are too complicated▫Must simply in order to model ▫Ignoring some details or parts so that you

can focus on what is important to you at that time.

▫As your interests change the amount of abstraction you need can change too.

Assumptions• Abstraction involves assumptions (things that

you take to be true). Before abstraction During abstraction After abstraction during model development

• Assumptions are what the modeler assumes when moving from the real world problem to a model.

Sometimes a simplification Sometimes a specification

• Assumptions need to be carefully considered Affect the outcome of the model Should be validated

Pond Ecosystem

Applying Abstraction:Modeling Rabbit’s Ecosystem

oLiving Rabbit Characteristics

• Birth• Death• Metabolism• Infection

People Plants Other animals Microscopic

There are many things that affect Rabbit populations: oNonliving

Water Soil Weather Disasters Pollution

Applying Abstraction:Modeling Rabbit’s Ecosystem

oLiving Rabbit Characteristics

• Birth• Death• Metabolism• Infection

People Plants Other animals Microscopic

There are many things that affect Rabbit populations: oNonliving

Water Soil Weather Disasters Pollution

•Run simple rabbit model

Applying Abstraction:Modeling Rabbit’s Ecosystem

oLiving Rabbit Characteristics

• Birth• Death• Metabolism• Infection

People Plants (+ regrowing) Other animals Microscopic

There are many things that affect Rabbit populations: oNonliving

Water Soil Weather Disasters Pollution

•Run more advanced rabbit model

Applying Abstraction:Modeling Rabbit’s Ecosystem

oLiving Rabbit Characteristics

• Birth▫ Birth rate

• Death• Metabolism• Infection

People Plants (+ regrowing)

▫Caloric value or energy Other animals

▫Birth rate Microscopic

There are many things that affect Rabbit populations: oNonliving

Water Soil Weather Disasters Pollution

Summary•Abstraction is required for modeling•Can vary the amount of abstraction as

needed•Abstraction involves assumption.•Assumptions can affect the outcome of the

model