Spatial Aggregation (SA) is a framework for organizing computations around image-like, analogue representations of physical processes in data interpretation and control tasks. It transforms a numerical input field (such as temperature throughout a room or wind velocity vectors sampled across the country) to successively higher-level descriptions by applying a small set of operators to each layer, given appropriate metrics, neighborhood relations, and equivalence relations.
Aggregation is the typical whole/part relationship. This is exactly the same as an association with the exception that instances cannot have cyclic aggregation relationships (i.e. a part cannot contain its whole).
[Example:] |Node|<>-------->|Node|class Node
{
private:
vector<Node*> itsNodes;
};
The fact that this is aggregation means that the instances of Node cannot form a cycle. Thus, this is a Tree of Nodes not a graph of Nodes.
Aggregation is the typical whole/part relationship. This is exactly the same as an association with the exception that instances cannot have cyclic aggregation relationships (i.e. a part cannot contain its whole).
[Example:] |Node|<>-------->|Node|class Node
{
private:
vector<Node*> itsNodes;
};
The fact that this is aggregation means that the instances of Node cannot form a cycle. Thus, this is a Tree of Nodes not a graph of Nodes.
如：[汽车]<>───[零件]
"<>"表示集团的聚合（aggregate）
普通情况下，聚合的多重性可以是任意整数。如果部件是集团整体中不可分离的一部分，则该集团称为复合。如：圆和圆心是复合关系。