Graphical Modelling in Simile : Object- or agent-based

Object- or agent-based modelling in Simile

A submodel is a distinct group of components in a model, and can represent a class. Submodels with specified dimensions have a fixed number of potential instances. Population submodels represent groups of individuals who appear, move, reproduce and disappear according to the four process or channel symbols -- creation, immigration, reproduction and loss.

A role arrow causes the submodel at the head to have an instance or group of instances for each instance of that at its tail, as if it were nested inside. Each role arrow multiplies the potential number of instances of the submodel at its head. This can contain condition symbols, which allow the existence of each instance to be turned on or off.

The alarm symbol indicates that when the model values are updated, the components in its submodel should be evaluated repeatedly until the alarm's test condition is met. Condition and alarm symbols have slightly different effects when influenced by events. A conditional submodel only exists at the point at which the triggering event occurs, while an alarm submodel's components are only re-evaluated (but maybe many times) when the triggering event occurs, and keep the same values at other times.

submodel

An envelope enclosing a group of model elements, collectively representing a class of object

initialisation

A process creating the initial number of instances of a population submodel

migration

A process creating new instances of a population submodel

reproduction

A process creating new instances of a population submodel for each existing instance

extermination

A process destroying instances of a population submodel

role

Represents the fact that one object is associated with another, with each playing a role in the association

condition

Represents the fact that an instance of a submodel can exist only under specific conditions

alarm

Represents an iterative loop within a single time-step

 

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