[Left] [Up] [Right] The Second-Generation (Semantic) Web [Left] [Up] [Right]

Objectives of the Semantic Web

  • Today's Web is designed for presentation of content to humans.
  • Humans are expected to interpret and understand the meaning of the content.

The Semantic Web is an extension of the current web. It aims to:

  • Give information a well-defined meaning, thereby creating a pathway for machine-to-machine communication and automated serives based on descriptions of semantics.

Modeling

The Semantic Web Layer Cake

Figure 1. The Semantic Web Layer Cake (Berners-Lee, 2002).

The Semantic Web is an extension of the current web.

  1. URIs are just links in today's web. Unicode is 16-bit representation of (multilingual) characters.

  2. XML files and web resources capture objects and classes. XML separates structure from presentation. XML assumes data/information can be represented in hierarchies.

  3. RDF (resource description framework) describes relationships between objects and classes in a general but simple way. RDF separates content from structure, thereby allowing for the merging of multiple conceptual models. RDF represents data/information in graphs.

  4. Ontologies provide a formal conceptualization (semantic representation) of a particular domain shared by a group of people. Languages include: Darpa Agent Markup Language (DAML) and Web Ontology Language (OWL).

  5. The logic layer allows for reasoning. Languages include: RuleML. Reasoning tools include Jess and MANDARAX.

  6. Ontology-based applications will be built on top of the Semantic Web infrastructure (i.e., XML, RDF and ontologies)

Section 7-3: April, 2003. [Left] [Up] [Right]