A network structure consists of vertices and edges. Vertices represent entities in a system, and edges between vertices represent relationships between entities.
Different types of entities can exist in different models. For example, in doing curriculum analysis, we model as entities the institution, the departments within the institution and the courses within departments.
Entities are represented as vertices. A vertex is assigned text and numeric attributes that represent information on the entity.
For example, the name of the entity can be an attribute. Similarly, an edge is assigned text and numeric attributes that describe the relationship, for example, the strength of the relationship expressed on a scale from 0 – 1.
For a directed edge, the relationship applies only in one direction — the direction of the edge matters and is indicated visually with an arrow. An undirected edge is bidirectional — the relationship applies in both directions.