Database Reference
In-Depth Information
early pays dividends. By being early to market in your sector, your Linked Data set
can become a hub to which many other datasets link, increasing your discovery rate.
Another benefit of Linked Data is that of trust and authority. Since every data
item is identified with a Uniform Resource Identifier (URI), the source of the data is
immediately clear. Although, as described further in this chapter, the Semantic Web
technology stack layer of Trust has yet to be fully developed, the ability to link back
to an original source is a first step in this direction.
Last but not least, Linked Data allows search results to be more dynamic. As new
data sources are published on the Web of Data, answers returned by semantic queries
become more
complete
, as they can include elements of the new data sources, rather
than merely that a new Web page pushes an older one further down the search results.
2.5
HOW IT WORKS
The Semantic Web is based on a number of related technologies, as shown in
Figure 2.2. This section is intended just to introduce the names and roles of the vari-
ous technologies so that the reader will survive the acronym overload that is to come.
The most significant technologies are discussed in more detail in further chapters,
but the main ideas are discussed next.
The bottom layer in the stack is made up of the Unicode character set for universal
encoding of text on the Web, along with identifiers that uniquely identify each data item
on the Web. Identification of things on the Web (known as “resources”) is achieved by
the use of URIs. The well-known URL (Uniform Resource Locator) or “Web address”
User Interface & Applications
Trust
Proof
Unifying Logic
Ontology:
OWL
Query:
SPARQL
Rule:
RIF
RDFS
Data interchange:
RDF
XML
URI/IRI
FIGURE 2.2
Semantic Web technology stack. IRI (Internationalized Resource Identifier)
= a superset of the URIs, which can include characters from the Universal Character
Set (that is, including characters from languages other than English). (From
http://www.
w3.org/2007/03/layerCake.png
Copyright © 2007 World Wide Web Consortium,
http://
www.w3.org/
[Massachusetts Institute of Technology,
http://www.csail.mit.edu/
; European
Research Consortium for Informatics and Mathematics,
http://www.ercim.org/
; Keio University,
http://www.keio.ac.jp/
]
. All rights reserved.)
