<s>
Ontology	B-Language
Grounded	O
Metalanguage	O
(	O
OGML	B-Language
)	O
is	O
a	O
metalanguage	O
like	O
MOF	B-Application
.	O
</s>
<s>
The	O
goal	O
of	O
OGML	B-Language
is	O
to	O
tackle	O
the	O
difficulties	O
of	O
MOF	B-Application
:	O
linear	B-General_Concept
modeling	I-General_Concept
architecture	O
,	O
ambiguous	O
constructs	O
and	O
incomprehensible/unclear	O
architecture	O
.	O
</s>
<s>
OGML	B-Language
provides	O
a	O
nested	O
modeling	O
architecture	O
with	O
three	O
fixed	O
layers	O
(	O
models	B-Application
,	O
languages	O
and	O
metalanguage	O
)	O
.	O
</s>
<s>
Therefore	O
,	O
it	O
is	O
clear	O
how	O
the	O
different	O
models	B-Application
conform	O
to	O
each	O
other	O
and	O
can	O
be	O
handled	O
.	O
</s>
<s>
Constructs	O
in	O
OGML	B-Language
are	O
chosen	O
from	O
the	O
science	O
of	O
ontology	B-Language
,	O
making	O
the	O
distinction	O
between	O
properties	O
/	O
objects	O
and	O
classes	O
/	O
objects	O
very	O
clear	O
.	O
</s>
<s>
Furthermore	O
,	O
OGML	B-Language
provides	O
an	O
explicit	O
notion	O
of	O
instantiation	O
:	O
model	O
elements	O
encode	O
their	O
types	O
and	O
languages	O
define	O
the	O
semantics	B-Application
of	O
instantiation	O
.	O
</s>
<s>
This	O
extra	O
information	O
is	O
needed	O
in	O
the	O
relative	O
modeling	O
architecture	O
to	O
distinguish	O
between	O
structural	O
and	O
conceptual	O
views	O
on	O
models	B-Application
,	O
for	O
example	O
:	O
we	O
may	O
want	O
to	O
view	O
a	O
UML	B-Application
model	I-Application
as	O
an	O
instance	O
of	O
the	O
object	O
language	O
and	O
an	O
instance	O
of	O
the	O
Class	O
model	O
(	O
Clabject	O
)	O
.	O
</s>
<s>
By	O
providing	O
this	O
dual	O
view	O
on	O
the	O
metamodel	O
layer	O
and	O
on	O
the	O
language	O
layer	O
,	O
OGML	B-Language
provides	O
a	O
very	O
precise	O
modeling	O
architecture	O
and	O
an	O
expressive	O
way	O
to	O
deal	O
with	O
models	B-Application
.	O
</s>
