<s>
Document	B-General_Concept
Structuring	I-General_Concept
is	O
a	O
subtask	O
of	O
Natural	B-General_Concept
language	I-General_Concept
generation	I-General_Concept
,	O
which	O
involves	O
deciding	O
the	O
order	O
and	O
grouping	O
(	O
for	O
example	O
into	O
paragraphs	O
)	O
of	O
sentences	O
in	O
a	O
generated	O
text	O
.	O
</s>
<s>
It	O
is	O
closely	O
related	O
to	O
the	O
Content	B-General_Concept
determination	I-General_Concept
NLG	O
task	O
.	O
</s>
<s>
The	O
document	B-General_Concept
structuring	I-General_Concept
task	O
is	O
to	O
choose	O
an	O
ordering	O
and	O
grouping	O
of	O
sentences	O
which	O
results	O
in	O
a	O
coherent	O
and	O
well-organised	O
text	O
from	O
the	O
reader	O
's	O
perspective	O
.	O
</s>
<s>
There	O
are	O
three	O
basic	O
approaches	O
to	O
document	B-General_Concept
structuring	I-General_Concept
:	O
schemas	O
,	O
corpus-based	O
,	O
and	O
heuristic	O
.	O
</s>
<s>
Schemas	O
are	O
templates	O
which	O
explicitly	O
specify	O
sentence	O
ordering	O
and	O
grouping	O
for	O
a	O
document	O
(	O
as	O
well	O
as	O
Content	B-General_Concept
determination	I-General_Concept
information	O
)	O
.	O
</s>
<s>
Such	O
techniques	O
are	O
common	O
in	O
Automatic	B-Application
summarisation	I-Application
,	O
where	O
a	O
computer	O
program	O
automatically	O
generates	O
a	O
summary	O
of	O
a	O
textual	O
document	O
.	O
</s>
<s>
In	O
principle	O
they	O
could	O
be	O
applied	O
to	O
text	O
generated	O
from	O
non-linguistic	O
data	O
,	O
but	O
this	O
work	O
is	O
in	O
its	O
infancy	O
;	O
part	O
of	O
the	O
challenge	O
is	O
that	O
texts	O
generated	O
by	O
Natural	B-General_Concept
Language	I-General_Concept
Generation	I-General_Concept
systems	O
are	O
generally	O
expected	O
to	O
be	O
of	O
fairly	O
high	O
quality	O
,	O
which	O
is	O
not	O
always	O
the	O
case	O
for	O
texts	O
generated	O
by	O
automatic	B-Application
summarisation	I-Application
systems	O
.	O
</s>
<s>
Perhaps	O
the	O
ultimate	O
document	B-General_Concept
structuring	I-General_Concept
challenge	O
is	O
to	O
generate	O
a	O
good	O
narrative	O
—	O
in	O
other	O
words	O
,	O
a	O
text	O
which	O
starts	O
by	O
setting	O
the	O
scene	O
and	O
giving	O
an	O
introduction/overview	O
;	O
then	O
describes	O
a	O
set	O
of	O
events	O
in	O
a	O
clear	O
fashion	O
so	O
readers	O
can	O
easily	O
see	O
how	O
the	O
individual	O
events	O
are	O
related	O
and	O
link	O
together	O
;	O
and	O
concludes	O
with	O
a	O
summary/ending	O
.	O
</s>
<s>
Generating	O
good	O
narratives	O
is	O
a	O
challenge	O
for	O
all	O
aspects	O
of	O
NLG	O
,	O
but	O
the	O
most	O
fundamental	O
challenge	O
is	O
probably	O
in	O
document	B-General_Concept
structuring	I-General_Concept
.	O
</s>
