<s>
The	O
Functional	B-Application
Mock-up	I-Application
Interface	I-Application
(	O
or	O
FMI	O
)	O
defines	O
a	O
standardized	O
interface	B-Application
to	O
be	O
used	O
in	O
computer	B-Application
simulations	I-Application
to	O
develop	O
complex	O
cyber-physical	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
To	O
create	O
the	O
FMI	O
standard	O
,	O
a	O
large	O
number	O
of	O
software	O
companies	O
and	O
research	O
centers	O
have	O
worked	O
in	O
a	O
cooperation	O
project	O
established	O
through	O
a	O
European	O
consortium	O
that	O
has	O
been	O
conducted	O
by	O
Dassault	O
Systèmes	O
under	O
the	O
name	O
of	O
MODELISAR	B-Application
.	O
</s>
<s>
The	O
MODELISAR	B-Application
project	O
started	O
in	O
2008	O
to	O
define	O
the	O
FMI	O
specifications	O
,	O
deliver	O
technology	O
studies	O
,	O
prove	O
the	O
FMI	O
concepts	O
through	O
use	O
cases	O
elaborated	O
by	O
the	O
consortium	O
partners	O
and	O
enable	O
tool	O
vendors	O
to	O
build	O
advanced	O
prototypes	O
or	O
in	O
some	O
cases	O
even	O
products	O
.	O
</s>
<s>
After	O
the	O
end	O
of	O
the	O
MODELISAR	B-Application
project	O
in	O
2011	O
,	O
FMI	O
is	O
managed	O
and	O
developed	O
as	O
a	O
.	O
</s>
<s>
The	O
four	O
required	O
FMI	O
aspects	O
of	O
creating	O
models	O
capable	O
of	O
being	O
assembled	O
have	O
been	O
covered	O
in	O
Modelisar	B-Application
project	O
:	O
</s>
<s>
These	O
models	O
can	O
be	O
large	O
for	O
usage	O
in	O
off-line	O
or	O
on-line	O
simulation	O
or	O
can	O
be	O
used	O
in	O
embedded	B-Architecture
control	I-Architecture
systems	O
;	O
</s>
<s>
several	O
FMUs	O
can	O
–	O
by	O
this	O
way	O
–	O
cooperate	O
at	O
runtime	O
through	O
a	O
co-simulation	O
environment	O
,	O
thanks	O
to	O
the	O
FMI	O
definitions	O
of	O
their	O
interfaces	B-Application
.	O
</s>
<s>
the	O
C-header	O
and	O
XML-schema	O
files	O
that	O
accompany	O
this	O
document	O
are	O
available	O
under	O
the	O
license	O
with	O
the	O
extension	O
that	O
modifications	O
must	O
also	O
be	O
provided	O
under	O
the	O
BSD	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
Each	O
FMU	O
(	O
Functional	O
Mock-up	O
Unit	O
)	O
is	O
distributed	O
in	O
a	O
zip	B-General_Concept
file	I-General_Concept
with	O
the	O
extension	O
"	O
.fmu	O
"	O
which	O
contains	O
:	O
</s>
<s>
all	O
the	O
equations	O
used	O
by	O
the	O
model	O
(	O
defined	O
as	O
a	O
set	O
of	O
C	B-Language
functions	O
)	O
;	O
</s>
<s>
optional	O
other	O
data	O
,	O
such	O
as	O
parameter	O
tables	O
,	O
user	O
interface	B-Application
,	O
documentation	O
which	O
may	O
be	O
needed	O
by	O
the	O
model	O
.	O
</s>
<s>
Below	O
is	O
an	O
example	O
of	O
an	O
FMI	O
model	O
description	O
issued	O
from	O
Modelica	B-Application
.	O
</s>
<s>
FMI	O
is	O
often	O
compared	O
to	O
Simulink	B-Application
S-Functions	O
since	O
both	O
technologies	O
can	O
be	O
used	O
to	O
integrate	O
third-party	O
tools	O
together	O
.	O
</s>
<s>
They	O
are	O
compiled	O
as	O
MEX-files	O
that	O
are	O
dynamically	O
linked	O
into	O
MATLAB	B-Language
when	O
needed	O
.	O
</s>
<s>
S-Functions	O
use	O
a	O
calling	O
syntax	O
that	O
interacts	O
with	O
Simulink	B-Application
’s	O
equation	O
solvers	O
.	O
</s>
<s>
This	O
interaction	O
is	O
similar	O
to	O
the	O
interaction	O
that	O
takes	O
place	O
between	O
built-in	O
Simulink	B-Application
blocks	O
and	O
the	O
solvers	O
.	O
</s>
<s>
FMI	O
proponents	O
explain	O
that	O
FMI	O
models	O
have	O
several	O
advantages	O
over	O
Simulink	B-Application
S-Functions	O
:	O
</s>
<s>
S-Functions	O
format	O
is	O
proprietary	O
,	O
whereas	O
the	O
FMI	O
schema	O
is	O
licensed	O
under	O
a	O
BSD	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
The	O
building	O
blocks	O
of	O
S-Functions	O
are	O
much	O
more	O
complex	O
than	O
FMI	O
,	O
making	O
it	O
very	O
difficult	O
to	O
integrate	O
in	O
simulators	O
other	O
than	O
Simulink	B-Application
itself	O
.	O
</s>
<s>
Furthermore	O
,	O
the	O
S-Functions	O
format	O
is	O
specific	O
to	O
Simulink	B-Application
.	O
</s>
<s>
S-Functions	O
are	O
not	O
suited	O
for	O
embedded	B-Architecture
systems	I-Architecture
,	O
due	O
to	O
the	O
memory	O
overhead	O
of	O
S-Functions	O
.	O
</s>
<s>
architecture	O
,	O
the	O
interfaces	B-Application
of	O
the	O
system	O
elements	O
,	O
and	O
their	O
connections	O
and	O
parameterization	O
.	O
</s>
