Temporal information detection
Introduction
The temporal-information
detector identifies and returns—in normalized format—the following time expressions:
Expression type | Description | Examples |
---|---|---|
Time point | A specific time | The Declaration was signed on July 4, 1776. The plane should take off at 3PM. In November 1996 I traveled to the United States. A big change took place in 2016. |
Time span | An amount of time units, from minutes up to years | It took her three minutes to find the solution. Your condition will continue to improve over the next two weeks. I have known her for more than ten years. |
Time interval | A time interval (from ... to ...) | He ruled the region from July 2005 to September 2011. |
Value normalization
Time point
Time point expressions are normalized according to the ISO 8601 standard. Here are some examples of value normalization:
- July 4, 1776 →
1776-07-04
- 3PM →
-----T15
- November 1996 →
1996-11
- 2016 →
2016
Time span
Time span expressions are normalized using this format:
[ sign ] quantity unit-of-measure
For example:
Seven days → 7 day
Possible units of measure are:
year
month
day
hour
minute
Quantity can be indefinite
, for example:
For some months I've been skeptical, but now I believe it. → indefinite month
Weeks are returned as days, centuries as years, etc. For example:
Two weeks → 14 day
The optional sign
can be +
(plus sign) or -
(minus sign) and denotes time spans that "add" or "subtract" time from an explicit or implicit time point. For example:
- The first agreement was in 2009. After eight years the companies merged. →
+ 8 year
, meaning eight years after 2009 - These events took place 30 years ago. →
- 30 year
, meaning thirty years before a time that was "this year"—but not further specified—for the writer or speaker.
Time interval
Time interval expression are normalized using this format:
"from" time point / "to" time point
Left and right time points are normalized according to the ISO 8601 standard. For example:
from July 2005 to September 2011 → 2005-07/2011-09
Derived time points
The detector is also capable of deriving time points from deixes referring to other time points.
In particular, the detector can derive a time point from:
-
"Before/after" expressions that are recognized as time spans and referred to a time point
For example, in:
I first traveled to Australia in 2002 and returned fifteen years later,
the expression fifteen years later is not recognizable as a time point by itself, but is recognized as a time span (normalized to
+ 15 year
) and, once referred to 2002—which is recognized as a time point—, makes the detector derive a new time point by adding the time span. In this case the new time point is2017
, which is 2002 + 15. -
"Equal to" expressions referred to a time point
For example, in:
We met on July 27, 2014. On the same day we became business partners.
the expression On the same day is not recognizable as a time point by itself, but once referred to July 27, 2014—which is recognized as a time point—and interpreted as "the same", makes the detector derive another occurrence of the explicit time point, in this case
2014-07-27
.
Derived time points are flagged as such in the detectors' output.
Useful resources
- How to request information detection API resources.
- How to interpret the output of the
temporal-information
detector.