Preface for the Third Edition - Read

376 B. Concepts and Theories
information about knowledge elements can be easily exchanged between a variety
of heterogeneous ICT systems.
semantic integration security
(12) logic framework, proof, trust
(11) ontology (Web Ontology Language - OWL)
(10) vocabulary (RDF Schema)
(9) description (Resource Description Framework - RDF)
data integration
(5) structure (XML schema) (6) translation (XSLT)
(3) text markup (XML) (4) scope (XML namespaces)
(1) addressing (URI) (2) character set (Unicode)
FIGURE B-72. Semantic integration with the Semantic Web stack
Data integration. Data integration requires that agents (users, institutions or applications)
exchanging data agree (1) how to address data resources over a network,
generally over the Internet, (2) about what character set to use, (3) about the internal
structure of documents, called text markup, (4) about the scope or domain in
which the specified names in the markup are valid, (5) about how to define a
schema, a structure of the elements and attributes in the semi-structured text and
(6) how to translate a document that is an instance of one schema so that it conforms
to another schema.
In the Semantic Web stack, (1) addressing uses Unified Resource Identifier
(URI). URIs are formulated in a standard syntax that is used to uniquely identify
objects (or resources) located in any directory on any machine on the Internet, particularly
on the World Wide Web, accessed via a specified access method. (2) The
Unicode Standard is the universal character encoding scheme for multilingual text.
It specifies a numeric value (code point), a name, its case, directionality, and alphabetic
properties for each of its characters. Modeled on the ASCII character set,
Unicode can encode all characters in all written languages in the world.
(3) The eXtensible Markup Language (XML) is a tag-based markup language
for describing tree structures. XML is a set of syntax rules for creating markup languages
used to define the structure of documents suitable for automatic processing,
i.e. extracting content and structure of XML documents and checking whether an
XML document conforms to rules defined by the XML standard, called wellformedness.
(4) XML markup defines a vocabulary, also called a markup vocabulary.
XML namespaces are a mechanism for creating universally unique names for
XML markup vocabularies so that they can be reused by other XML documents.
An XML namespace is a collection of names, identified by a URI reference, which
is used in XML documents as element and attribute names.
(5) In order to define classes of XML (instance) documents, a number of schema
definition languages have been developed that XML documents can be validated
(7) encryption
(8) signature