| Abstract |
The Semantic Web (SW) is an evolving extension of the World Wide Web in which the content can
be expressed not only in
natural language, but also in formal languages (e.g. RDF/S) that can be
read and used by software agents, permitting them to find, share and integrate information more
easily. S
emantic Web technologies form the foundation for publishing data according to t
he
principles of Linked Data.
Unf
ortunately, most web content is based on technologies that
do not
meet
the principles of the Semantic Web. T
he majority of
the
data
is available in relational
, object
-
oriented and NoSQL databases
.
For this reason several sy
stems have been developed for
converting and publishing content as
linked
data.
Ε
ach system follows
its
own
method
,
while
it is
worth noting
the R2RML mapping language
proposed by W3C as an official language for
expressing mappings from relational database
s in RDF datasets
.
In this
work
we focus on X3ML
language
;
a mapping
formalism
designed by the Institute of Computer Science of FORTH, which
is
human readable, generic enough to cover most of the data models used nowadays
and more
explicit with the URI
g
enerating process.
The main objective of this
MSc
thesis is to provide
a complete analysis
of
mappings
expressed in
X3ML language. First
ly,
we identify the main business use cases,
a)
Create a Mapping
in
which the
actor wants to
generate
a mapping from sc
ratch, b)
Improve a Mapping
in
which
the actor
needs
to improve it, check its quality, compare with others and monitor its evolution.
Based on these,
we defined
the
system requirements and then design
ed
and implement
ed
11
basic functionalities
.
These funct
ion
alities
refer to the
analysis
of
the
schema
s
involved in a particular mapping
,
the
calculation of
coverage metrics
, the graphical representation and comparison
of mappings
, and
the
monitor
ing of
their evolution.
More s
pecifically, the analysis
of schemas
offers the
opportunity o
f
navigat
ing
and better understand
ing
the
content. The coverage
metrics
give
an
overview of
the mapped
data and
allow
excluding elements that are considered undesirable for a
mapping
.
For the g
raphical representation
,
we
introduce
functionalities
that visualize
a mapping
,
focusing
on syntactic elements of
the
language, and
provide
a three
-
dimensional interactive
representation.
As
regards
comparisons,
several
function
alities are
offered
such as
textual
comparison of
mappings in XML
format
, representation of difference
s through graph
and
compari
son of
generated
instances
.
Finally, the
functionality
of
tracking
the
evolution of
a
mapping
helps the user
to identify
the
basic
points
that
have changed over time.
All in all
,
the
main novelty of this work is the interactivity of all functionalities and 3D visualization of mappings.
|
Mappings management for ontology - based integration
