<s>
NEPOMUK	B-Language
(	O
Networked	O
Environment	O
for	O
Personal	O
,	O
Ontology-based	O
Management	O
of	O
Unified	O
Knowledge	O
)	O
is	O
an	O
open-source	O
software	O
specification	O
that	O
is	O
concerned	O
with	O
the	O
development	O
of	O
a	O
social	O
semantic	B-Application
desktop	I-Application
that	O
enriches	O
and	O
interconnects	O
data	O
from	O
different	O
desktop	O
applications	O
using	O
semantic	O
metadata	O
stored	O
as	O
RDF	O
.	O
</s>
<s>
Between	O
2006	O
and	O
2008	O
it	O
was	O
funded	O
by	O
a	O
European	O
Union	O
research	O
project	O
of	O
the	O
same	O
name	O
that	O
grouped	O
together	O
industrial	O
and	O
academic	O
actors	O
to	O
develop	O
various	O
Semantic	B-Application
Desktop	I-Application
technologies	O
.	O
</s>
<s>
Three	O
active	O
implementations	O
of	O
NEPOMUK	B-Language
exist	O
:	O
A	O
C++	B-Language
/KDE	O
-based	O
variant	O
,	O
a	O
Java-based	O
variant	O
,	O
and	O
a	O
commercial	O
version	O
.	O
</s>
<s>
NEPOMUK-KDE	B-Language
was	O
originally	O
featured	O
as	O
one	O
of	O
the	O
newer	O
technologies	O
in	O
KDE	B-Language
Software	I-Language
Compilation	I-Language
4	I-Language
.	O
</s>
<s>
It	O
used	O
Soprano	B-Application
as	O
the	O
main	O
RDF	O
data	O
storage	O
and	O
parsing	O
library	O
,	O
while	O
handling	O
ontology	B-Language
imports	O
through	O
the	O
Raptor	B-Language
parser	I-Language
plugin	I-Language
and	O
the	O
Redland	B-Language
storage	I-Language
plugin	I-Language
;	O
all	O
RDF	O
data	O
was	O
stored	O
by	O
Virtuoso	B-Application
which	O
also	O
handled	O
full-text	O
indexing	O
.	O
</s>
<s>
On	O
a	O
technical	O
level	O
,	O
NEPOMUK-KDE	B-Language
allowed	O
associating	O
metadata	O
to	O
various	O
items	O
present	O
on	O
a	O
normal	O
user	O
's	O
desktop	O
such	O
as	O
files	O
,	O
bookmarks	O
,	O
e-mails	O
,	O
and	O
calendar	O
entries	O
.	O
</s>
<s>
As	O
the	O
KDE	B-Language
SC	I-Language
4	I-Language
series	O
of	O
releases	O
progressed	O
,	O
it	O
became	O
apparent	O
that	O
NEPOMUK	B-Language
was	O
not	O
delivering	O
the	O
performance	O
and	O
user	O
experience	O
that	O
had	O
initially	O
been	O
anticipated	O
.	O
</s>
<s>
As	O
a	O
result	O
of	O
this	O
,	O
in	O
KDE	O
SC	O
4.13	O
a	O
new	O
indexing	O
and	O
semantic	O
search	O
technology	O
Baloo	O
was	O
introduced	O
,	O
with	O
a	O
short	O
transition	O
period	O
allowing	O
applications	O
to	O
be	O
ported	O
and	O
data	O
to	O
be	O
migrated	O
before	O
the	O
removal	O
of	O
NEPOMUK	B-Language
.	O
</s>
<s>
for	O
storage	O
,	O
and	O
Xapian	B-Application
for	O
searching	O
.	O
</s>
<s>
The	O
Zeitgeist	B-Language
framework	O
,	O
used	O
by	O
GNOME	B-Application
and	O
Ubuntu	O
's	O
Unity	B-Device
user	I-Device
interface	I-Device
,	O
uses	O
the	O
NEPOMUK	B-Language
ontology	B-Language
,	O
as	O
does	O
the	O
Tracker	B-Application
search	O
engine	O
.	O
</s>
<s>
The	O
Java-based	O
implementation	O
of	O
NEPOMUK	B-Language
was	O
finished	O
at	O
the	O
end	O
of	O
2008	O
and	O
served	O
as	O
a	O
proof-of-concept	O
environment	O
for	O
several	O
novel	O
semantic	B-Application
desktop	I-Application
techniques	O
.	O
</s>
<s>
The	O
Java	B-Language
implementation	O
uses	O
the	O
Sesame	O
RDF	O
store	O
and	O
the	O
Aperture	O
framework	O
for	O
integrating	O
with	O
other	O
desktop	O
applications	O
such	O
as	O
mail	O
clients	O
and	O
browsers	O
.	O
</s>
<s>
A	O
number	O
of	O
artifacts	O
have	O
been	O
created	O
in	O
the	O
context	O
of	O
the	O
Java	B-Language
research	O
implementation	O
:	O
</s>
<s>
Implementation	O
of	O
the	O
commercial	O
Software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
product	O
Refinder	O
started	O
in	O
2009	O
and	O
a	O
limited	O
beta-version	O
was	O
released	O
in	O
December	O
2010	O
.	O
</s>
<s>
Refinder	O
was	O
developed	O
by	O
Gnowsis	O
,	O
a	O
spin-off	O
company	O
of	O
the	O
German	O
Research	O
Centre	O
for	O
Artificial	O
Intelligence	O
(	O
DFKI	O
)	O
(	O
project	O
lead	O
in	O
the	O
NEPOMUK	B-Language
EU	O
project	O
)	O
.	O
</s>
<s>
Refinder	O
uses	O
the	O
same	O
data	O
formats	O
as	O
the	O
other	O
implementations	O
,	O
but	O
using	O
Software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
instead	O
of	O
the	O
desktop	O
approach	O
of	O
the	O
other	O
implementations	O
.	O
</s>
<s>
PIMO	O
the	O
data	O
format	O
used	O
for	O
describing	O
a	O
Personal	O
Information	O
Model	O
,	O
describing	O
Persons	O
,	O
Projects	O
,	O
Topics	O
,	O
Events	O
,	O
etc.	O
,	O
also	O
used	O
in	O
NEPOMUK-KDE	B-Language
.	O
</s>
<s>
NIE	O
the	O
NEPOMUK	B-Language
Information	O
Element	O
Ontology	B-Language
(	O
and	O
the	O
associated	O
ontologies	B-Language
NFO	O
etc	O
.	O
</s>
