Information

When all resources are described with semantic languages,the Web becomes a huge database.

ICT: Information – Communication – Technology

It has been nearly two decades that television, telecommunications and information technology converge. Indeed, it is especially the evolution of the computer technology that has redistributed the cards and helped to blur the boundaries of the two others.

ICTs include a set of resources to handle “information” via computers, programs and networks essential to its creation, storage, management, transmission, archiving, research and discovery.

Essentially, these tools manipulate and transport data’s but they don't deal with information and communication wich are based on other concepts:

  • Information is the meaning that humans assign to data by means of conventions. Information requires languages and dictionaries. It can be stored and it is used to communicate in time and space.
  • Communication is a process by which living organisms define and share meaning. Communication requires a sender, a message that wraps information and a receiver. It can be remote in time and space.

Linguistic and semantic

In Europe it is Ferdinand de Saussure who founded modern linguistics and laid the foundations of semiotics. The basic idea of Saussure is that language is a closed system of signs. Any sign is defined in relation to others, for pure difference (negatively), and not by its own characteristics ("positive") and so it constitutes a "system". He distinguishes two different signs:

  • The signifier refers to the graphical representation of a term, a picture, a sound.
    What is important in the representation, is the differences that distinguish them from each other.
  • The signified is the concept, that is to say, a semantic representation associated with a meaning.
    This observation leads Saussure also distinguished meaning and value since the existence of different languages necessarily introduces different values for a same meanings

The cognitive process

Cognitive psychology studies the major psychological functions of human beings that are memory, language, intelligence, reasoning, problem solving, perception and attention. Cognition more generally is defined as the set of mental activities and processes relating to knowledge and to the function that makes it.

The notion of information system is at the heart of cognitive models: symbolic formalizations (cognition as a system of symbol manipulation), rather connectionist (cognition seen as flow activation in a large neural network), or hybrid (concept of a large neural network that performs functionally a system of symbols).

So the concept of information (and Knowledge)is deeply embedded in a cognitive process!

The semantic web architecture

The central idea of the Semantic Web initiative is to make the meaning of Web content machine accessible. It relies on the combination of the following technologies:

  • Explicit metadata: they allow Web pages to carry their meaning on their sleeves.
  • Ontologies: they describe the main concepts of a domain and their relationships.
  • Logical reasoning: it makes it possible to draw conclusions from combining (meta)data with ontologies.

HTML

HTML is a standard language relying on a set of predefined tags, which control the appearance of a Web page. It is the signifier layer for a linguist as De Saussure.

XML

XML allows users to define their own tags. It's a domain-independent mark-up meta-language wich separates content from formatting. XML is the first layer of the signified for a linguist.

RDF

RDF is a framework that has been implemented in XML language for describing resources. Its basic building block is a statement, a triple consisting of an entity (called resource in Web terminology), a property, and a value. RDF is domain-independent. It is up to the user to define her own terminology in a schema language called RDF Schema. RDF and RDF Schema provide the basic core languages for the Semantic Web.

OWL

OWL was designed as a new standard Web ontology language. It is based on top RDF/S, and seeks to find a balance between expressive power and efficient reasoning support.

Logics

The formal foundation of the OWL language is a branch of knowledge representation and reasoning called description logics.

LOD (Linked Open Data)

In a conventional index, you must define a list of metadata. Usually this is done in XML. Unfortunately, these metadata’s properties and relationships are only interpretable by humans.

What the audio-visual industry needs is:

  • Add to the existing contents machine-readable metadata so that information can be analyzed, questioned, reused.
  • Define the relationships shared by these metadata to enable interoperability between applications, but also allow the identification of new relationships by reasoning and machines inferences.

It is therefore essential to design documents that havethe information in a form accessible by the machine and keepthe links created with the relationship values.

The Semantic Web helps the machine in the interpretation of information contained on a web page providing the following advantages:

  • Programs and sites may share information
  • Search tools are able to display more relevant information
  • The data mashers are likely to combine information from different sources to create new and surprising relationships (serendipity search)

All of these resources can be distributed through the Web in a distributed and federated data Graph. And when all resources are described with semantic languages (explicit metadata, relationships), the Web becomes a huge database...

Finally it is the ontology that provides the common semantics for resources on the Semantic Web!

Evolution of the Semantic Web

Linking Open Data (LOD) is not a standard, but a project to link all the semantic databases in the form of "Linked Data", and to obtain a large network, composed by growing database.

Thus, the challenge of LOD is to link all these databases, via HTTP links so that they can be part of the LOD community.

The universe of interconnected data (Linked Data) uses the Web to link semantic databases (RDF, ..) that were not connected, or to simplify the level of data links connected by other methods.