<s>
GOMS	O
is	O
a	O
specialized	O
human	B-General_Concept
information	I-General_Concept
processor	I-General_Concept
model	I-General_Concept
for	O
human-computer	O
interaction	O
observation	O
that	O
describes	O
a	O
user	O
's	O
cognitive	O
structure	O
on	O
four	O
components	O
.	O
</s>
<s>
For	O
a	O
simple	O
applied	O
example	O
see	O
CMN-GOMS	B-General_Concept
.	O
</s>
<s>
Basically	O
there	O
are	O
five	O
different	O
GOMS	O
models	O
:	O
the	O
Keystroke-Level	B-General_Concept
Model	I-General_Concept
,	O
CMN-GOMS	B-General_Concept
,	O
NGOMSL	B-General_Concept
,	O
CPM-GOMS	B-General_Concept
,	O
and	O
SGOMS	B-Architecture
.	O
</s>
<s>
The	O
Keystroke-Level	B-General_Concept
Model	I-General_Concept
(	O
KLM	B-General_Concept
)	O
is	O
the	O
first	O
and	O
simplest	O
GOMS	O
technique	O
Stuart	O
Card	O
,	O
Thomas	O
P	O
.	O
Moran	O
and	O
Allen	O
Newell	O
created	O
.	O
</s>
<s>
With	O
KLM	B-General_Concept
the	O
analyst	O
must	O
specify	O
the	O
method	O
used	O
to	O
accomplish	O
each	O
particular	O
task	O
instance	O
.	O
</s>
<s>
The	O
biggest	O
difference	O
between	O
GOMS	O
and	O
KLM	B-General_Concept
is	O
how	O
time	O
is	O
assigned	O
to	O
cognitive	O
and	O
perceptual	O
operators	O
when	O
it	O
comes	O
to	O
execution	O
time	O
predictions	O
.	O
</s>
<s>
Another	O
major	O
difference	O
is	O
that	O
the	O
goal-hierarchy	O
is	O
explicit	O
in	O
GOMS	O
while	O
it	O
was	O
implicit	O
in	O
the	O
KLM	B-General_Concept
.	O
</s>
<s>
KLM	B-General_Concept
has	O
a	O
single	O
M	O
operator	O
that	O
precedes	O
each	O
cognitive	O
unit	O
of	O
action	O
.	O
</s>
<s>
KLM	B-General_Concept
's	O
execution	O
part	O
is	O
described	O
in	O
four	O
physical-motor	O
operators	O
:	O
</s>
<s>
This	O
addition	O
to	O
the	O
GOMS	O
family	O
,	O
together	O
with	O
updates	O
to	O
the	O
existing	O
KLM	B-General_Concept
operators	O
,	O
is	O
called	O
the	O
Touch	O
Level	O
Model	O
(	O
TLM	O
)	O
.	O
</s>
<s>
CMN-GOMS	B-General_Concept
is	O
the	O
original	O
GOMS	O
model	O
proposed	O
by	O
Stuart	O
Card	O
,	O
Thomas	O
P	O
.	O
Moran	O
and	O
Allen	O
Newell	O
.	O
</s>
<s>
CMN	O
stands	O
for	O
Card	O
,	O
Moran	O
and	O
Newell	O
and	O
it	O
takes	O
the	O
KLM	B-General_Concept
as	O
its	O
basic	O
and	O
adds	O
subgoals	O
and	O
selection	O
rules	O
.	O
</s>
<s>
A	O
CMN-GOMS	B-General_Concept
model	O
can	O
be	O
represented	O
in	O
program	O
form	O
,	O
making	O
it	O
amenable	O
to	O
analysis	O
as	O
well	O
as	O
execution	O
.	O
</s>
<s>
CMN-GOMS	B-General_Concept
has	O
been	O
used	O
to	O
model	O
word	O
processors	O
and	O
CAD	B-Application
systems	O
for	O
ergonomic	O
design(see CAD )	O
.	O
</s>
<s>
In	O
the	O
example	O
by	O
Bonnie	O
E	O
.	O
John	O
and	O
David	O
E	O
.	O
Kieras	O
a	O
simple	O
CMN-GOMS	B-General_Concept
on	O
editing	O
a	O
manuscript	O
is	O
shown	O
.	O
</s>
<s>
NGOMSL	B-General_Concept
is	O
a	O
structured	O
natural	O
language	O
notation	O
for	O
representing	O
GOMS	O
models	O
and	O
a	O
procedure	O
for	O
constructing	O
them	O
.	O
</s>
<s>
This	O
model	O
explicitly	O
represents	O
the	O
goal	O
structure	O
just	O
like	O
the	O
CMN-GOMS	B-General_Concept
and	O
can	O
so	O
represent	O
high-level	O
goals	O
.	O
</s>
<s>
CMN-GOMS	B-General_Concept
,	O
KLM	B-General_Concept
and	O
NGOMSL	B-General_Concept
assume	O
that	O
all	O
of	O
the	O
operators	O
occur	O
in	O
sequence	O
and	O
do	O
not	O
contain	O
operators	O
that	O
are	O
below	O
the	O
activity	O
level	O
.	O
</s>
<s>
CPM-GOMS	B-General_Concept
being	O
the	O
fourth	O
method	O
uses	O
operators	O
at	O
the	O
level	O
of	O
Model	B-General_Concept
Human	I-General_Concept
Processor	I-General_Concept
which	O
assumes	O
that	O
operators	O
of	O
the	O
cognitive	O
processor	O
,	O
perceptual	O
processor	O
,	O
and	O
the	O
motor	O
processor	O
can	O
work	O
in	O
parallel	O
to	O
each	O
other	O
.	O
</s>
<s>
The	O
most	O
important	O
point	O
of	O
CPM-GOMS	B-General_Concept
is	O
the	O
ability	O
to	O
predict	O
skilled	O
behavior	O
from	O
its	O
ability	O
to	O
model	O
overlapping	O
actions	O
.	O
</s>
<s>
SGOMS	B-Architecture
stands	O
for	O
Sociotechnical	O
GOMS	O
and	O
was	O
created	O
to	O
allow	O
GOMS	O
to	O
model	O
work	O
in	O
complex	O
sociotechnical	O
systems	O
.	O
</s>
<s>
SGOMS	B-Architecture
is	O
meant	O
to	O
expand	O
the	O
applicability	O
of	O
GOMS	O
to	O
the	O
macro	O
cognitive	O
level	O
of	O
analysis	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
SGOMS	B-Architecture
adds	O
a	O
high	O
level	O
control	O
structure	O
to	O
GOMS	O
,	O
called	O
the	O
planning	O
unit	O
.	O
</s>
<s>
Consistent	O
with	O
CPM-GOMS	B-General_Concept
,	O
SGOMS	B-Architecture
assumes	O
that	O
the	O
agent	O
can	O
monitor	O
the	O
situation	O
in	O
parallel	O
in	O
order	O
to	O
detect	O
threats	O
(	O
neurophysiologically	O
,	O
this	O
function	O
is	O
associated	O
with	O
the	O
amygdala	O
)	O
.	O
</s>
<s>
SGOMS	B-Architecture
does	O
not	O
prescribe	O
how	O
this	O
choice	O
is	O
made	O
but	O
,	O
if	O
the	O
decision	O
is	O
based	O
on	O
routine	O
expertise	O
,	O
it	O
can	O
be	O
included	O
in	O
the	O
SGOMS	B-Architecture
model	O
.	O
</s>
<s>
A	O
successful	O
implementation	O
of	O
CPM-GOMS	B-General_Concept
was	O
in	O
Project	O
Ernestine	O
held	O
by	O
New	O
England	O
Telephone	O
.	O
</s>
<s>
CPM-GOMS	B-General_Concept
analysis	O
estimated	O
a	O
3%	O
decrease	O
in	O
productivity	O
.	O
</s>
<s>
However	O
CPM-GOMS	B-General_Concept
analysis	O
made	O
it	O
apparent	O
that	O
the	O
problem	O
was	O
that	O
the	O
new	O
workstations	O
did	O
not	O
utilize	O
the	O
workers	O
 '	O
slack	O
time	O
.	O
</s>
<s>
Not	O
only	O
did	O
CPM-GOMS	B-General_Concept
give	O
a	O
close	O
estimate	O
,	O
but	O
it	O
provided	O
more	O
information	O
of	O
the	O
situation	O
.	O
</s>
<s>
GOMS	O
models	O
were	O
employed	O
in	O
the	O
redesign	O
of	O
a	O
CAD	B-Application
(	O
computer-aided	B-Application
design	I-Application
)	O
system	O
for	O
industrial	O
ergonomics	O
.	O
</s>
