2.5.1.1 Internet

  2.5.1.1.1 Physical structure

  2.5.1.1.2 Virtual structure

2.5.1.2 Knowledge representation and organization

  2.5.1.2.1. Databases

  2.5.1.2.2 Extended markup language (XML)

  2.5.1.2.3 Ontologies

2.5.1.3 Agents

  2.5.1.3.1 Mobile agents

2.5.1.4 Human-computer interaction

  2.5.1.4.1 Program interfaces