<s>
In	O
computing	O
,	O
a	O
natural	B-Application
user	I-Application
interface	I-Application
(	O
NUI	O
)	O
or	O
natural	O
interface	O
is	O
a	O
user	B-Application
interface	I-Application
that	O
is	O
effectively	O
invisible	O
,	O
and	O
remains	O
invisible	O
as	O
the	O
user	O
continuously	O
learns	O
increasingly	O
complex	O
interactions	O
.	O
</s>
<s>
Examples	O
include	O
voice	B-Protocol
assistants	I-Protocol
,	O
such	O
as	O
Alexa	O
and	O
Siri	O
,	O
touch	O
and	O
multitouch	B-Application
interactions	O
on	O
today	O
's	O
mobile	O
phones	O
and	O
tablets	O
,	O
but	O
also	O
touch	B-Application
interfaces	I-Application
invisibly	O
integrated	O
into	O
the	O
textiles	O
furnitures	O
.	O
</s>
<s>
One	O
strategy	O
is	O
the	O
use	O
of	O
a	O
"	O
reality	O
user	B-Application
interface	I-Application
"	O
(	O
"	O
RUI	O
"	O
)	O
,	O
also	O
known	O
as	O
"	O
reality-based	O
interfaces	O
"	O
(	O
RBI	O
)	O
methods	O
.	O
</s>
<s>
One	O
example	O
of	O
an	O
RUI	O
strategy	O
is	O
to	O
use	O
a	O
wearable	B-Operating_System
computer	I-Operating_System
to	O
render	O
real-world	O
objects	O
"	O
clickable	O
"	O
,	O
i.e.	O
</s>
<s>
Because	O
this	O
design	O
is	O
coincident	O
with	O
a	O
direct-touch	O
display	O
,	O
non-designers	O
commonly	O
misattribute	O
the	O
effortlessness	O
of	O
interacting	O
with	O
the	O
device	O
to	O
that	O
multi-touch	B-Application
display	O
,	O
and	O
not	O
to	O
the	O
design	O
of	O
the	O
software	O
where	O
it	O
actually	O
resides	O
.	O
</s>
<s>
In	O
the	O
1990s	O
,	O
Steve	O
Mann	O
developed	O
a	O
number	O
of	O
user-interface	B-Application
strategies	O
using	O
natural	O
interaction	O
with	O
the	O
real	O
world	O
as	O
an	O
alternative	O
to	O
a	O
command-line	B-Application
interface	I-Application
(	O
CLI	O
)	O
or	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
.	O
</s>
<s>
Mann	O
referred	O
to	O
this	O
work	O
as	O
"	O
natural	B-Application
user	I-Application
interfaces	I-Application
"	O
,	O
"	O
Direct	O
User	B-Application
Interfaces	I-Application
"	O
,	O
and	O
"	O
metaphor-free	O
computing	O
"	O
.	O
</s>
<s>
Mann	O
's	O
EyeTap	B-General_Concept
technology	O
typically	O
embodies	O
an	O
example	O
of	O
a	O
natural	B-Application
user	I-Application
interface	I-Application
.	O
</s>
<s>
A	O
good	O
example	O
of	O
an	O
NUI	O
in	O
both	O
these	O
senses	O
is	O
the	O
hydraulophone	O
,	O
especially	O
when	O
it	O
is	O
used	O
as	O
an	O
input	B-Device
device	I-Device
,	O
in	O
which	O
touching	O
a	O
natural	O
element	O
(	O
water	O
)	O
becomes	O
a	O
way	O
of	O
inputting	O
data	O
.	O
</s>
<s>
More	O
generally	O
,	O
a	O
class	O
of	O
musical	O
instruments	O
called	O
"	O
physiphones	O
"	O
,	O
so-named	O
from	O
the	O
Greek	O
words	O
"	O
physika	O
"	O
,	O
"	O
physikos	O
"	O
(	O
nature	O
)	O
and	O
"	O
phone	O
"	O
(	O
sound	O
)	O
have	O
also	O
been	O
proposed	O
as	O
"	O
Nature-based	O
user	B-Application
interfaces	I-Application
"	O
.	O
</s>
<s>
In	O
a	O
2008	O
conference	O
presentation	O
"	O
Predicting	O
the	O
Past	O
,	O
"	O
August	O
de	O
los	O
Reyes	O
,	O
a	O
Principal	O
User	O
Experience	O
Director	O
of	O
Surface	O
Computing	O
at	O
Microsoft	O
described	O
the	O
NUI	O
as	O
the	O
next	O
evolutionary	O
phase	O
following	O
the	O
shift	O
from	O
the	O
CLI	O
to	O
the	O
GUI	B-Application
.	O
</s>
<s>
Of	O
course	O
,	O
this	O
too	O
is	O
an	O
over-simplification	O
,	O
since	O
NUIs	O
necessarily	O
include	O
visual	O
elements	O
–	O
and	O
thus	O
,	O
graphical	B-Application
user	I-Application
interfaces	I-Application
.	O
</s>
<s>
A	O
more	O
accurate	O
description	O
of	O
this	O
concept	O
would	O
be	O
to	O
describe	O
it	O
as	O
a	O
transition	O
from	O
WIMP	B-Application
to	O
NUI	O
.	O
</s>
<s>
Then	O
,	O
when	O
the	O
mouse	O
enabled	O
the	O
GUI	B-Application
,	O
users	O
could	O
more	O
easily	O
learn	O
the	O
mouse	O
movements	O
and	O
actions	O
,	O
and	O
were	O
able	O
to	O
explore	O
the	O
interface	O
much	O
more	O
.	O
</s>
<s>
The	O
GUI	B-Application
relied	O
on	O
metaphors	O
for	O
interacting	O
with	O
on-screen	O
content	O
or	O
objects	O
.	O
</s>
<s>
"	O
Now	O
a	O
new	O
wave	O
of	O
products	O
is	O
poised	O
to	O
bring	O
natural	B-Application
user	I-Application
interfaces	I-Application
,	O
as	O
these	O
methods	O
of	O
controlling	O
electronics	O
devices	O
are	O
called	O
,	O
to	O
an	O
even	O
broader	O
audience.	O
"	O
</s>
<s>
In	O
2010	O
,	O
Daniel	O
Wigdor	O
and	O
Dennis	O
Wixon	O
provided	O
an	O
operationalization	O
of	O
building	O
natural	B-Application
user	I-Application
interfaces	I-Application
in	O
their	O
book	O
.	O
</s>
<s>
In	O
it	O
,	O
they	O
carefully	O
distinguish	O
between	O
natural	B-Application
user	I-Application
interfaces	I-Application
,	O
the	O
technologies	O
used	O
to	O
achieve	O
them	O
,	O
and	O
reality-based	O
UI	O
.	O
</s>
<s>
When	O
Bill	O
Buxton	O
was	O
asked	O
about	O
the	O
iPhone	O
's	O
interface	O
,	O
he	O
responded	O
"	O
Multi-touch	B-Application
technologies	I-Application
have	O
a	O
long	O
history	O
.	O
</s>
<s>
Multi-Touch	B-Application
is	O
a	O
technology	O
which	O
could	O
enable	O
a	O
natural	B-Application
user	I-Application
interface	I-Application
.	O
</s>
<s>
However	O
,	O
most	O
UI	O
toolkits	O
used	O
to	O
construct	O
interfaces	O
executed	O
with	O
such	O
technology	O
are	O
traditional	O
GUIs	B-Application
.	O
</s>
<s>
One	O
example	O
is	O
the	O
work	O
done	O
by	O
Jefferson	O
Han	O
on	O
multi-touch	B-Application
interfaces	O
.	O
</s>
<s>
In	O
a	O
GUI	B-Application
interface	O
for	O
a	O
design	O
application	O
for	O
example	O
,	O
a	O
user	O
would	O
use	O
the	O
metaphor	O
of	O
'	O
tools	O
 '	O
to	O
do	O
this	O
,	O
for	O
example	O
,	O
selecting	O
a	O
prod	O
tool	O
,	O
or	O
selecting	O
two	O
parts	O
of	O
the	O
mass	O
that	O
they	O
then	O
wanted	O
to	O
apply	O
a	O
'	O
pinch	O
 '	O
action	O
to	O
.	O
</s>
<s>
Microsoft	B-General_Concept
PixelSense	I-General_Concept
takes	O
similar	O
ideas	O
on	O
how	O
users	O
interact	O
with	O
content	O
,	O
but	O
adds	O
in	O
the	O
ability	O
for	O
the	O
device	O
to	O
optically	O
recognize	O
objects	O
placed	O
on	O
top	O
of	O
it	O
.	O
</s>
<s>
"	O
3D	O
Immersive	O
Touch	O
"	O
is	O
defined	O
as	O
the	O
direct	O
manipulation	O
of	O
3D	O
virtual	O
environment	O
objects	O
using	O
single	O
or	O
multi-touch	B-Application
surface	O
hardware	O
in	O
multi-user	O
3D	O
virtual	O
environments	O
.	O
</s>
<s>
Coined	O
first	O
in	O
2007	O
to	O
describe	O
and	O
define	O
the	O
3D	O
natural	B-Application
user	I-Application
interface	I-Application
learning	O
principles	O
associated	O
with	O
Edusim	B-General_Concept
.	O
</s>
<s>
Immersive	O
Touch	O
natural	B-Application
user	I-Application
interface	I-Application
now	O
appears	O
to	O
be	O
taking	O
on	O
a	O
broader	O
focus	O
and	O
meaning	O
with	O
the	O
broader	O
adaption	O
of	O
surface	O
and	O
touch	O
driven	O
hardware	O
such	O
as	O
the	O
iPhone	O
,	O
iPod	O
touch	O
,	O
iPad	O
,	O
and	O
a	O
growing	O
list	O
of	O
other	O
hardware	O
.	O
</s>
<s>
Apple	O
also	O
seems	O
to	O
be	O
taking	O
a	O
keen	O
interest	O
in	O
“	O
Immersive	O
Touch	O
”	O
3D	O
natural	B-Application
user	I-Application
interfaces	I-Application
over	O
the	O
past	O
few	O
years	O
.	O
</s>
<s>
Kinect	B-Algorithm
is	O
a	O
motion	O
sensing	O
input	B-Device
device	I-Device
by	O
Microsoft	O
for	O
the	B-Operating_System
Xbox	I-Operating_System
360	I-Operating_System
video	B-Device
game	I-Device
console	I-Device
and	O
Windows	O
PCs	B-Device
that	O
uses	O
spatial	O
gestures	O
for	O
interaction	O
instead	O
of	O
a	O
game	B-Device
controller	I-Device
.	O
</s>
<s>
According	O
to	O
Microsoft	O
's	O
page	O
,	O
Kinect	B-Algorithm
is	O
designed	O
for	O
"	O
a	O
revolutionary	O
new	O
way	O
to	O
play	O
:	O
no	O
controller	O
required.	O
"	O
.	O
</s>
<s>
Again	O
,	O
because	O
Kinect	B-Algorithm
allows	O
the	O
sensing	O
of	O
the	O
physical	O
world	O
,	O
it	O
shows	O
potential	O
for	O
RBI	O
designs	O
,	O
and	O
thus	O
potentially	O
also	O
for	O
NUI	O
.	O
</s>
