The document discusses Michele Filannino's final presentation on identifying temporal expressions in biomedical texts. It provides context on natural language processing and information extraction. It then defines temporal expressions and discusses their importance for tasks like question answering and summarization. The presentation outlines the forms temporal expressions can take, common annotation and normalization methods used, and gives an example. It also notes the lack of freely available corpora and describes Filannino's contributions of building the first freely available timex corpus and a temporal expression normalizer. The presentation concludes with discussing some examples of human annotation mistakes and Filannino's remaining to-do items.

1. COMP80122: final presentation
temporal expressions
identification in biomedical texts
Michele Filannino
Manchester, 29/02/2012

2. presentation temporal expressions
where we are
■ Computer science
● natural language processing
▶ information extraction
★ temporal expressions extraction
29/02/2012, Michele Filannino 2 / 23

3. presentation temporal expressions
temporal expression definition
■ natural language phrase that denotes a temporal
entity: an interval, or an instant (Ferro et Al.)1
● She has been at work for more than a month
● He wrapped up a three-hour meeting with the Iraqi
president in Baghdad today.
1 L.
Ferro, I. Mani, B. Sundheim, and G. Wilson, “Tides temporal annotation
guidelines, v. 1.0.2,” MITRE, 2001
29/02/2012, Michele Filannino 3 / 23

4. presentation temporal expressions
why?
■ user’s perspective
● temporal aspects of events and entities provide a
natural mechanism for organising information.
■ machine’s perspective
● improvements in
▶ question answering, summarisation, browsing
29/02/2012, Michele Filannino 4 / 23

5. presentation temporal expressions
why clinical domain?
■ diagnosis explanation
■ disease progression
modelling
■ analysis of effectiveness of
treatment
29/02/2012, Michele Filannino 5 / 23

6. presentation temporal expressions
scientific interest
“temporal expressions” AND “clinical”
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14 25
18 16
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10 12 10
0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Source: Google Scholar (last update 27/02/2012) 29/02/2012, Michele Filannino 6 / 23

7. presentation temporal expressions
temporal forms 1
■ time or date references
● 11pm, February 14th, 2005
■ time references that anchor on another time
● one hour after midnight, two weeks before Christmas
■ durations
● few months, two days, five years
■ recurring times
● every third month, twice in the hour
1 J.
Poveda, M. Surdeanu, and J. Turmo, “An analysis of Bootstrapping for the
Recognition of Temporal Expressions”, 2009
29/02/2012, Michele Filannino 7 / 23

8. presentation temporal expressions
temporal forms 1
■ context-dependent times
● today, last year
■ vague references
● somewhere in the middle of June, the near future
■ times indicated by an event
● the day S. Berlusconi resigned
▶ an event is considered a cover term for situations that
happen or occur
1 J.
Poveda, M. Surdeanu, and J. Turmo, “An analysis of Bootstrapping for the
Recognition of Temporal Expressions”, 2009
29/02/2012, Michele Filannino 8 / 23

9. presentation temporal expressions
methodology
■ annotation
● recognition
▶ automatically detect and delimitate expressions
▶ mostly machine-learning techniques
● normalisation
▶ assign attributes values for all the recognised
expressions
▶ using a shared and formal format
▶ mostly rule-based techniques
■ reasoning or searching
29/02/2012, Michele Filannino 9 / 23

10. presentation temporal expressions
example: raw text
That means Unisys must pay about $100 million in interest every
quarter, on top of $27 million in dividends on preferred stock.
Source: TRIOS TimeBank v.0.1 29/02/2012, Michele Filannino 10 / 23

11. presentation temporal expressions
example: recognition
That means Unisys must <ev>pay</ev> about $100 million in
interest <te>every quarter</te>, on top of $27 million in
dividends on preferred stock.
Source: TRIOS TimeBank v.0.1 29/02/2012, Michele Filannino 11 / 23

12. presentation temporal expressions
example: normalisation
That means Unisys must <EVENT eid="e110" ...>pay</EVENT>
about $100 million in interest <TIMEX3 tid="t256" type="SET"
value="P1Q" temporalFunction="false"
functionInDocument="NONE" quant="every">every quarter</
TIMEX3>, on top of $27 million in dividends on preferred stock.
<TLINK lid="l32" relType="BEFORE" relatedToEvent="e110"
eventID="e107"/>
<TLINK lid="l26" relType="OVERLAP" eventID="e110"
relatedToTime="t256"/>
Source: TRIOS TimeBank v.0.1 29/02/2012, Michele Filannino 12 / 23

13. presentation temporal expressions
lack of corpora
29/02/2012, Michele Filannino 13 / 23

14. presentation temporal expressions
my contributions
■ built the first timex corpus using all the possible
freely available timexes
● {timex, type, normalised_value, utterance_reference}
● 2822 different timexes
■ built a normaliser
● as TRIOS’ extension (University of Rochester)
● 71.66% accuracy from 62.57%
29/02/2012, Michele Filannino 14 / 23

15. presentation temporal expressions
human mistakes
utterance expression type annotation
- three years before DATE FUTURE_REF
26/09/2011 this morning DATE 1998-02-06TMO
- two decades DURATION P20Y
- the summer of 1862 DATE FUTURE_REF
- centuries DURATION PXE
- the last half of ‘80s DATE 198
29/02/2012, Michele Filannino 15 / 23

16. presentation temporal expressions
my to-do list
✓ study the literature
✓ build a corpus of timexes
✓ build a normaliser
■ release my timexes corpus freely
■ literature review
22 days elapsed 8 days remaining
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29/02/2012, Michele Filannino 16 / 23

17. Thank you.