<s>
A	O
tangible	O
user	B-Application
interface	I-Application
(	O
TUI	O
)	O
is	O
a	O
user	B-Application
interface	I-Application
in	O
which	O
a	O
person	O
interacts	O
with	O
digital	B-General_Concept
information	I-General_Concept
through	O
the	O
physical	O
environment	O
.	O
</s>
<s>
The	O
initial	O
name	O
was	O
Graspable	O
User	B-Application
Interface	I-Application
,	O
which	O
is	O
no	O
longer	O
used	O
.	O
</s>
<s>
The	O
purpose	O
of	O
TUI	O
development	O
is	O
to	O
empower	O
collaboration	O
,	O
learning	O
,	O
and	O
design	O
by	O
giving	O
physical	O
forms	O
to	O
digital	B-General_Concept
information	I-General_Concept
,	O
thus	O
taking	O
advantage	O
of	O
the	O
human	O
ability	O
to	O
grasp	O
and	O
manipulate	O
physical	O
objects	O
and	O
materials	O
.	O
</s>
<s>
One	O
of	O
the	O
pioneers	O
in	O
tangible	O
user	B-Application
interfaces	I-Application
is	O
Hiroshi	O
Ishii	O
,	O
a	O
professor	O
at	O
the	O
MIT	O
who	O
heads	O
the	O
Tangible	O
Media	O
Group	O
at	O
the	O
MIT	O
Media	O
Lab	O
.	O
</s>
<s>
His	O
particular	O
vision	O
for	O
tangible	O
UIs	O
,	O
called	O
Tangible	O
Bits	O
,	O
is	O
to	O
give	O
physical	O
form	O
to	O
digital	B-General_Concept
information	I-General_Concept
,	O
making	O
bits	O
directly	O
manipulable	O
and	O
perceptible	O
.	O
</s>
<s>
Physical	O
representations	O
are	O
computationally	O
coupled	O
to	O
underlying	O
digital	B-General_Concept
information	I-General_Concept
.	O
</s>
<s>
Physical	O
representations	O
are	O
perceptually	O
coupled	O
to	O
actively	O
mediated	O
digital	B-General_Concept
representations	O
.	O
</s>
<s>
According	O
to	O
Mi	O
Jeong	O
Kim	O
and	O
Mary	O
Lou	O
Maher	O
,	O
the	O
five	O
basic	O
defining	O
properties	O
of	O
tangible	O
user	B-Application
interfaces	I-Application
are	O
as	O
follows	O
:	O
</s>
<s>
A	O
tangible	O
user	B-Application
interface	I-Application
must	O
be	O
differentiated	O
from	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
.	O
</s>
<s>
A	O
GUI	B-Application
exists	O
only	O
in	O
the	O
digital	B-General_Concept
world	O
,	O
whereas	O
a	O
TUI	O
connects	O
the	O
digital	B-General_Concept
with	O
the	O
physical	O
world	O
.	O
</s>
<s>
For	O
example	O
a	O
screen	O
displays	O
the	O
digital	B-General_Concept
information	I-General_Concept
,	O
whereas	O
a	O
mouse	O
allows	O
us	O
to	O
directly	O
interact	O
with	O
this	O
digital	B-General_Concept
information	I-General_Concept
.	O
</s>
<s>
A	O
tangible	O
user	B-Application
interface	I-Application
represents	O
the	O
input	O
directly	O
in	O
the	O
physical	O
world	O
,	O
and	O
makes	O
the	O
digital	B-General_Concept
information	I-General_Concept
directly	O
graspable	O
.	O
</s>
<s>
A	O
tangible	O
user	B-Application
interface	I-Application
is	O
usually	O
built	O
for	O
one	O
specific	O
target	O
group	O
,	O
because	O
of	O
the	O
low	O
range	O
of	O
possible	O
application	O
areas	O
.	O
</s>
<s>
In	O
comparison	O
with	O
a	O
TUI	O
,	O
a	O
GUI	B-Application
has	O
a	O
wide	O
range	O
of	O
usages	O
in	O
one	O
interface	O
.	O
</s>
<s>
That	O
is	O
why	O
the	O
Tangible	O
User	B-Application
interface	I-Application
is	O
often	O
used	O
to	O
make	O
technology	O
more	O
accessible	O
for	O
elderly	O
people	O
.	O
</s>
<s>
Marble	B-Application
Answering	O
Machine	O
by	O
Durrell	O
Bishop	O
(	O
1992	O
)	O
.	O
</s>
<s>
A	O
marble	B-Application
represents	O
a	O
single	O
message	O
left	O
on	O
the	O
answering	O
machine	O
.	O
</s>
<s>
Dropping	O
a	O
marble	B-Application
into	O
a	O
dish	O
plays	O
back	O
the	O
associated	O
message	O
or	O
calls	O
back	O
the	O
caller	O
.	O
</s>
<s>
The	O
blocks	O
in	O
Topobo	O
are	O
like	O
LEGO	B-Language
blocks	O
which	O
can	O
be	O
snapped	O
together	O
,	O
but	O
can	O
also	O
move	O
by	O
themselves	O
using	O
motorized	O
components	O
.	O
</s>
<s>
This	O
system	O
would	O
integrate	O
a	O
video	O
camera	O
with	O
a	O
gesture	B-General_Concept
recognition	I-General_Concept
system	O
.	O
</s>
<s>
For	O
example	O
,	O
Siftables	B-Application
provides	O
an	O
application	O
platform	O
in	O
which	O
small	O
gesture	O
sensitive	O
displays	O
act	O
together	O
to	O
form	O
a	O
human-computer	O
interface	O
.	O
</s>
<s>
Interest	O
in	O
tangible	O
user	B-Application
interfaces	I-Application
(	O
TUIs	O
)	O
has	O
grown	O
constantly	O
since	O
the	O
1990s	O
,	O
and	O
with	O
every	O
year	O
,	O
more	O
tangible	O
systems	O
are	O
showing	O
up	O
.	O
</s>
<s>
The	O
Urp	O
system	O
and	O
the	O
more	O
advanced	O
Augmented	O
Urban	O
Planning	O
Workbench	O
allow	O
digital	B-General_Concept
simulations	O
of	O
air	O
flow	O
,	O
shadows	O
,	O
reflections	O
,	O
and	O
other	O
data	O
based	O
on	O
the	O
positions	O
and	O
orientations	O
of	O
physical	O
models	O
of	O
buildings	O
,	O
on	O
the	O
table	O
surface	O
.	O
</s>
<s>
Beside	O
multi-touch	B-Application
tracking	O
of	O
fingers	O
,	O
the	O
platform	O
supports	O
the	O
recognition	O
of	O
physical	O
objects	O
by	O
their	O
footprints	O
.	O
</s>
<s>
A	O
physical	B-General_Concept
icon	I-General_Concept
,	O
or	O
phicon	O
,	O
is	O
the	O
tangible	O
computing	O
equivalent	O
of	O
an	O
icon	O
in	O
a	O
traditional	O
graphical	B-Application
user	I-Application
interface	I-Application
,	O
or	O
GUI	B-Application
.	O
</s>
<s>
Phicons	O
hold	O
a	O
reference	O
to	O
some	O
digital	B-General_Concept
object	O
and	O
thereby	O
convey	O
meaning	O
.	O
</s>
<s>
Physical	B-General_Concept
icons	I-General_Concept
were	O
first	O
used	O
as	O
tangible	O
interfaces	O
in	O
the	O
metaDesk	O
project	O
built	O
in	O
1997	O
by	O
Professor	O
Hiroshi	O
Ishii	O
's	O
tangible	O
bits	O
research	O
group	O
at	O
MIT	O
.	O
</s>
