<s>
Temporal	B-General_Concept
annotation	I-General_Concept
is	O
the	O
study	O
of	O
how	O
to	O
automatically	O
add	O
semantic	O
information	O
regarding	O
time	O
to	O
natural	O
language	O
documents	O
.	O
</s>
<s>
It	O
plays	O
a	O
role	O
in	O
natural	B-Language
language	I-Language
processing	I-Language
and	O
computational	O
linguistics	O
.	O
</s>
<s>
Temporal	B-General_Concept
annotation	I-General_Concept
involves	O
the	O
application	O
of	O
a	O
semantic	O
annotation	O
to	O
a	O
document	O
.	O
</s>
<s>
Significant	O
temporal	B-General_Concept
annotation	I-General_Concept
standards	O
include	O
TimeML	B-Language
,	O
ISO-TimeML	O
and	O
TIDES	O
.	O
</s>
<s>
Allen	B-Application
's	I-Application
interval	I-Application
algebra	I-Application
is	O
one	O
scheme	O
for	O
types	O
of	O
temporal	O
relations	O
.	O
</s>
<s>
Rule-engineering	O
and	O
machine	O
learning	O
approaches	O
to	O
temporal	B-General_Concept
annotation	I-General_Concept
have	O
both	O
been	O
successful	O
,	O
though	O
achieving	O
high	O
performance	O
in	O
temporal	O
relation	O
typing	O
remains	O
a	O
difficult	O
task	O
.	O
</s>
<s>
Successful	O
temporal	B-General_Concept
annotation	I-General_Concept
enables	O
systems	O
to	O
find	O
out	O
when	O
facts	O
asserted	O
in	O
texts	O
are	O
true	O
,	O
to	O
build	O
timelines	O
,	O
to	O
extract	O
plans	O
,	O
and	O
to	O
discover	O
mentions	O
of	O
change	O
.	O
</s>
<s>
This	O
has	O
had	O
applications	O
in	O
many	O
domains	O
,	O
such	O
as	O
information	B-General_Concept
extraction	I-General_Concept
,	O
digital	O
history	O
,	O
processing	O
social	O
media	O
,	O
and	O
clinical	B-Application
text	B-Algorithm
mining	I-Algorithm
.	O
</s>
<s>
The	O
TempEval	O
task	O
series	O
sets	O
a	O
shared	O
temporal	B-General_Concept
annotation	I-General_Concept
task	O
,	O
and	O
has	O
run	O
at	O
SemEval	B-General_Concept
three	O
times	O
,	O
attracting	O
system	O
entries	O
from	O
around	O
the	O
world	O
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
i2b2	O
clinical	B-Application
evaluation	O
shared	O
task	O
was	O
a	O
temporal	B-General_Concept
annotation	I-General_Concept
exercise	O
in	O
2012	O
,	O
which	O
attracted	O
a	O
great	O
deal	O
of	O
interest	O
.	O
</s>
