<s>
The	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
(	O
UML	B-Language
)	O
is	O
a	O
general-purpose	O
modeling	B-Language
language	I-Language
that	O
is	O
intended	O
to	O
provide	O
a	O
standard	O
way	O
to	O
visualize	O
the	O
design	O
of	O
a	O
system	O
.	O
</s>
<s>
UML	B-Language
provides	O
a	O
standard	O
notation	O
for	O
many	O
types	O
of	O
diagrams	O
which	O
can	O
be	O
roughly	O
divided	O
into	O
3	O
main	O
groups	O
:	O
behavior	O
diagrams	O
,	O
interaction	O
diagrams	O
,	O
and	O
structure	B-Language
diagrams	I-Language
.	O
</s>
<s>
The	O
creation	O
of	O
UML	B-Language
was	O
originally	O
motivated	O
by	O
the	O
desire	O
to	O
standardize	O
the	O
disparate	O
notational	O
systems	O
and	O
approaches	O
to	O
software	O
design	O
.	O
</s>
<s>
In	O
1997	O
,	O
UML	B-Language
was	O
adopted	O
as	O
a	O
standard	O
by	O
the	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
(	O
OMG	O
)	O
,	O
and	O
has	O
been	O
managed	O
by	O
this	O
organization	O
ever	O
since	O
.	O
</s>
<s>
In	O
2005	O
,	O
UML	B-Language
was	O
also	O
published	O
by	O
the	O
International	O
Organization	O
for	O
Standardization	O
(	O
ISO	O
)	O
as	O
an	O
approved	O
ISO	O
standard	O
.	O
</s>
<s>
Since	O
then	O
the	O
standard	O
has	O
been	O
periodically	O
revised	O
to	O
cover	O
the	O
latest	O
revision	O
of	O
UML	B-Language
.	O
</s>
<s>
In	O
software	O
engineering	O
,	O
most	O
practitioners	O
do	O
not	O
use	O
UML	B-Language
,	O
but	O
instead	O
produce	O
informal	O
hand	O
drawn	O
diagrams	O
;	O
these	O
diagrams	O
,	O
however	O
,	O
often	O
include	O
elements	O
from	O
UML	B-Language
.	O
</s>
<s>
UML	B-Language
has	O
been	O
evolving	O
since	O
the	O
second	O
half	O
of	O
the	O
1990s	O
and	O
has	O
its	O
roots	O
in	O
the	O
object-oriented	B-Language
programming	I-Language
methods	O
developed	O
in	O
the	O
late	O
1980s	O
and	O
early	O
1990s	O
.	O
</s>
<s>
The	O
timeline	O
(	O
see	O
image	O
)	O
shows	O
the	O
highlights	O
of	O
the	O
history	O
of	O
object-oriented	B-Language
modeling	O
methods	O
and	O
notation	O
.	O
</s>
<s>
It	O
is	O
originally	O
based	O
on	O
the	O
notations	O
of	O
the	O
Booch	O
method	O
,	O
the	O
object-modeling	B-Application
technique	I-Application
(	O
OMT	B-Application
)	O
and	O
object-oriented	B-Language
software	I-Language
engineering	I-Language
(	O
OOSE	B-Language
)	O
,	O
which	O
it	O
has	O
integrated	O
into	O
a	O
single	O
language	O
.	O
</s>
<s>
Rational	O
Software	O
Corporation	O
hired	O
James	O
Rumbaugh	O
from	O
General	O
Electric	O
in	O
1994	O
and	O
after	O
that	O
the	O
company	O
became	O
the	O
source	O
for	O
two	O
of	O
the	O
most	O
popular	O
object-oriented	B-Language
modeling	O
approaches	O
of	O
the	O
day	O
:	O
Rumbaugh	O
's	O
object-modeling	B-Application
technique	I-Application
(	O
OMT	B-Application
)	O
and	O
Grady	O
Booch	O
's	O
method	O
.	O
</s>
<s>
They	O
were	O
soon	O
assisted	O
in	O
their	O
efforts	O
by	O
Ivar	O
Jacobson	O
,	O
the	O
creator	O
of	O
the	O
object-oriented	B-Language
software	I-Language
engineering	I-Language
(	O
OOSE	B-Language
)	O
method	O
,	O
who	O
joined	O
them	O
at	O
Rational	O
in	O
1995	O
.	O
</s>
<s>
Under	O
the	O
technical	O
leadership	O
of	O
those	O
three	O
(	O
Rumbaugh	O
,	O
Jacobson	O
and	O
Booch	O
)	O
,	O
a	O
consortium	O
called	O
the	O
UML	B-Language
Partners	I-Language
was	O
organized	O
in	O
1996	O
to	O
complete	O
the	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
(	O
UML	B-Language
)	O
specification	O
,	O
and	O
propose	O
it	O
to	O
the	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
(	O
OMG	O
)	O
for	O
standardization	O
.	O
</s>
<s>
The	O
UML	B-Language
Partners	I-Language
 '	O
UML	B-Language
1.0	O
draft	O
was	O
proposed	O
to	O
the	O
OMG	O
in	O
January	O
1997	O
by	O
the	O
consortium	O
.	O
</s>
<s>
During	O
the	O
same	O
month	O
the	O
UML	B-Language
Partners	I-Language
formed	O
a	O
group	O
,	O
designed	O
to	O
define	O
the	O
exact	O
meaning	O
of	O
language	O
constructs	O
,	O
chaired	O
by	O
Cris	O
Kobryn	O
and	O
administered	O
by	O
Ed	O
Eykholt	O
,	O
to	O
finalize	O
the	O
specification	O
and	O
integrate	O
it	O
with	O
other	O
standardization	O
efforts	O
.	O
</s>
<s>
The	O
result	O
of	O
this	O
work	O
,	O
UML	B-Language
1.1	O
,	O
was	O
submitted	O
to	O
the	O
OMG	O
in	O
August	O
1997	O
and	O
adopted	O
by	O
the	O
OMG	O
in	O
November	O
1997	O
.	O
</s>
<s>
As	O
with	O
database	O
Chen	O
,	O
Bachman	O
,	O
and	O
ISO	O
ER	B-Architecture
diagrams	I-Architecture
,	O
class	O
models	O
are	O
specified	O
to	O
use	O
"	O
look-across	O
"	O
cardinalities	B-Application
,	O
even	O
though	O
several	O
authors	O
(	O
Merise	B-General_Concept
,	O
Elmasri	O
&	O
Navathe	O
amongst	O
others	O
)	O
prefer	O
same-side	O
or	O
"	O
look-here	O
"	O
for	O
roles	O
and	O
both	O
minimum	O
and	O
maximum	O
cardinalities	B-Application
.	O
</s>
<s>
have	O
shown	O
that	O
the	O
"	O
look-across	O
"	O
technique	O
used	O
by	O
UML	B-Language
and	O
ER	B-Architecture
diagrams	I-Architecture
is	O
less	O
effective	O
and	O
less	O
coherent	O
when	O
applied	O
to	O
n-ary	O
relationships	O
of	O
order	O
strictly	O
greater	O
than	O
2	O
.	O
</s>
<s>
Feinerer	O
says	O
:	O
"	O
Problems	O
arise	O
if	O
we	O
operate	O
under	O
the	O
look-across	O
semantics	O
as	O
used	O
for	O
UML	B-Language
associations	O
.	O
</s>
<s>
UML	B-Language
Diagram	I-Language
Interchange	O
version	O
1.0	O
.	O
</s>
<s>
Since	O
version	O
2.5	O
,	O
the	O
UML	B-Language
Specification	O
has	O
been	O
simplified	O
(	O
without	O
Superstructure	O
and	O
Infrastructure	O
)	O
,	O
and	O
the	O
latest	O
versions	O
of	O
these	O
standards	O
are	O
now	O
:	O
</s>
<s>
UML	B-Language
offers	O
a	O
way	O
to	O
visualize	O
a	O
system	O
's	O
architectural	O
blueprints	O
in	O
a	O
diagram	O
,	O
including	O
elements	O
such	O
as	O
:	O
</s>
<s>
any	O
activities	B-Language
(	O
jobs	O
)	O
;	O
</s>
<s>
individual	O
components	B-Language
of	O
the	O
system	O
;	O
</s>
<s>
and	O
how	O
they	O
can	O
interact	O
with	O
other	O
software	B-Architecture
components	I-Architecture
;	O
</s>
<s>
how	O
entities	O
interact	O
with	O
others	O
(	O
components	B-Language
and	O
interfaces	O
)	O
;	O
</s>
<s>
external	O
user	B-Application
interface	I-Application
.	O
</s>
<s>
Although	O
originally	O
intended	O
for	O
object-oriented	B-Language
design	O
documentation	O
,	O
UML	B-Language
has	O
been	O
extended	O
to	O
a	O
larger	O
set	O
of	O
design	O
documentation	O
(	O
as	O
listed	O
above	O
)	O
,	O
and	O
been	O
found	O
useful	O
in	O
many	O
contexts	O
.	O
</s>
<s>
UML	B-Language
is	O
not	O
a	O
development	O
method	O
by	O
itself	O
;	O
however	O
,	O
it	O
was	O
designed	O
to	O
be	O
compatible	O
with	O
the	O
leading	O
object-oriented	B-Language
software	O
development	O
methods	O
of	O
its	O
time	O
,	O
for	O
example	O
OMT	B-Application
,	O
Booch	O
method	O
,	O
Objectory	B-Application
and	O
especially	O
RUP	B-Application
that	O
it	O
was	O
originally	O
intended	O
to	O
be	O
used	O
with	O
when	O
work	O
began	O
at	O
Rational	O
Software	O
.	O
</s>
<s>
It	O
is	O
important	O
to	O
distinguish	O
between	O
the	O
UML	B-Language
model	O
and	O
the	O
set	O
of	O
diagrams	O
of	O
a	O
system	O
.	O
</s>
<s>
UML	B-Language
diagrams	I-Language
represent	O
two	O
different	O
views	O
of	O
a	O
system	O
model	O
:	O
</s>
<s>
It	O
includes	O
class	O
diagrams	O
and	O
composite	O
structure	B-Language
diagrams	I-Language
.	O
</s>
<s>
This	O
view	O
includes	O
sequence	O
diagrams	O
,	O
activity	O
diagrams	O
and	O
state	B-Application
machine	I-Application
diagrams	I-Application
.	O
</s>
<s>
UML	B-Language
models	O
can	O
be	O
exchanged	O
among	O
UML	B-Protocol
tools	I-Protocol
by	O
using	O
the	O
XML	B-Language
Metadata	I-Language
Interchange	I-Language
(	O
XMI	O
)	O
format	O
.	O
</s>
<s>
In	O
UML	B-Language
,	O
one	O
of	O
the	O
key	O
tools	O
for	O
behavior	O
modeling	O
is	O
the	O
use-case	O
model	O
,	O
caused	O
by	O
OOSE	B-Language
.	O
</s>
<s>
UML	B-Language
2	I-Language
has	O
many	O
types	O
of	O
diagrams	O
,	O
which	O
are	O
divided	O
into	O
two	O
categories	O
.	O
</s>
<s>
Structure	B-Language
diagrams	I-Language
represent	O
the	O
static	O
aspects	O
of	O
the	O
system	O
.	O
</s>
<s>
Since	O
structure	B-Language
diagrams	I-Language
represent	O
the	O
structure	O
,	O
they	O
are	O
used	O
extensively	O
in	O
documenting	O
the	O
software	B-Architecture
architecture	I-Architecture
of	O
software	O
systems	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
component	B-Library
diagram	I-Library
describes	O
how	O
a	O
software	O
system	O
is	O
split	O
up	O
into	O
components	B-Language
and	O
shows	O
the	O
dependencies	O
among	O
these	O
components	B-Language
.	O
</s>
<s>
As	O
an	O
example	O
,	O
the	O
activity	O
diagram	O
describes	O
the	O
business	O
and	O
operational	O
step-by-step	O
activities	B-Language
of	O
the	O
components	B-Language
in	O
a	O
system	O
.	O
</s>
<s>
The	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
(	O
OMG	O
)	O
has	O
developed	O
a	O
metamodeling	O
architecture	O
to	O
define	O
the	O
UML	B-Language
,	O
called	O
the	O
Meta-Object	B-Application
Facility	I-Application
.	O
</s>
<s>
This	O
M3-model	O
is	O
the	O
language	O
used	O
by	O
Meta-Object	B-Application
Facility	I-Application
to	O
build	O
metamodels	O
,	O
called	O
M2-models	O
.	O
</s>
<s>
The	O
most	O
prominent	O
example	O
of	O
a	O
Layer	O
2	O
Meta-Object	B-Application
Facility	I-Application
model	O
is	O
the	O
UML	B-Language
metamodel	O
,	O
which	O
describes	O
the	O
UML	B-Language
itself	O
.	O
</s>
<s>
These	O
would	O
be	O
,	O
for	O
example	O
,	O
models	O
written	O
in	O
UML	B-Language
.	O
</s>
<s>
The	O
meta-model	O
can	O
be	O
extended	O
using	O
a	O
mechanism	O
called	O
stereotyping	B-Language
.	O
</s>
<s>
This	O
has	O
been	O
criticized	O
as	O
being	O
insufficient/untenable	O
by	O
Brian	O
Henderson-Sellers	O
and	O
Cesar	O
Gonzalez-Perez	O
in	O
"	O
Uses	O
and	O
Abuses	O
of	O
the	O
Stereotype	B-Language
Mechanism	O
in	O
UML	B-Language
1.x	O
and	O
2.0	O
"	O
.	O
</s>
<s>
UML	B-Language
has	O
been	O
marketed	O
for	O
many	O
contexts	O
.	O
</s>
<s>
UML	B-Language
misuse	O
includes	O
overuse	O
(	O
designing	O
every	O
part	O
of	O
the	O
system	O
with	O
it	O
,	O
which	O
is	O
unnecessary	O
)	O
and	O
assuming	O
that	O
novices	O
can	O
design	O
with	O
it	O
.	O
</s>
<s>
Some	O
people	O
(	O
including	O
Jacobson	O
)	O
feel	O
that	O
UML	B-Language
's	O
size	O
hinders	O
learning	O
(	O
and	O
therefore	O
using	O
)	O
it	O
.	O
</s>
