<s>
Usage-centered	B-General_Concept
design	I-General_Concept
is	O
an	O
approach	O
to	O
user	O
interface	O
design	O
based	O
on	O
a	O
focus	O
on	O
user	O
intentions	O
and	O
usage	O
patterns	O
.	O
</s>
<s>
It	O
analyzes	O
users	O
in	O
terms	O
of	O
the	O
roles	O
they	O
play	O
in	O
relation	O
to	O
systems	O
and	O
employs	O
abstract	O
(	O
essential	O
)	O
use	B-Architecture
cases	I-Architecture
for	O
task	O
analysis	O
.	O
</s>
<s>
It	O
derives	O
visual	O
and	O
interaction	B-General_Concept
design	I-General_Concept
from	O
abstract	O
prototypes	O
based	O
on	O
the	O
understanding	O
of	O
user	O
roles	O
and	O
task	O
cases	O
.	O
</s>
<s>
Usage-centered	B-General_Concept
design	I-General_Concept
was	O
introduced	O
by	O
Larry	O
Constantine	O
and	O
Lucy	O
Lockwood	O
.	O
</s>
<s>
Usage-centered	B-General_Concept
design	I-General_Concept
is	O
largely	O
based	O
on	O
formal	O
,	O
abstract	O
models	O
such	O
as	O
models	O
of	O
interaction	O
between	O
user	O
roles	O
,	O
UML	B-Language
workflow	O
models	O
and	O
task	O
case	O
and	O
role	O
profiles	O
.	O
</s>
<s>
Usage-centered	B-General_Concept
design	I-General_Concept
proponents	O
argue	O
for	O
abstract	O
modelling	O
while	O
many	O
designers	O
use	O
realistic	O
personas	O
,	O
scenarios	O
and	O
high-fidelity	O
prototypes	O
.	O
</s>
<s>
Usage-centered	B-General_Concept
design	I-General_Concept
share	O
some	O
common	O
ideas	O
with	O
activity-centered	B-General_Concept
design	I-General_Concept
.	O
</s>
<s>
Constantine	O
(	O
2006	O
)	O
presents	O
an	O
integrated	O
framework	O
where	O
the	O
models	O
of	O
Usage-centered	B-General_Concept
design	I-General_Concept
are	O
enriched	O
with	O
concepts	O
from	O
the	O
Activity	O
theory	O
.	O
</s>
