Information Technology Reference
In-Depth Information
5.1
Activity Extraction
Table 1 shows the comparison results of our approach with baseline method, and Nguyen
et al. [19]. Based on the results, we can see that the baseline has high precision but low
recall. The reason is that sentences retrieved from twitter are often diversified, complex,
syntactically wrong. Nguyen et al. also used self-supervised learning and CRF, but it
could not handle complex sentences.
Ta b l e 1 . Comparison of our approach with baseline, and Nguyen et al, (2011)
@
Method
Activity
Actor
Act
Object
Time
Location
Baseline 81.17% 86.32% 98.13% 84.14% 87.96% 88.25%
Nguyen et al. 57.89% 72.79% 82.98% 67.01% 76.40% 80.20%
Our approach 73.21% 82.25% 97.11% 81.23% 80.04% 82.11%
Precision
Baseline 23.86% 26.38% 28.87% 24.77% 26.20% 26.02%
Nguyen et al. 51.13% 69.13% 90.23% 62.11% 73.51% 77.67%
Our approach 66.54% 80.11% 93.18% 76.57% 79.75% 81.02%
Recall
Baseline 36.88% 40.41% 44.61% 38.27% 40.37% 40.19%
Nguyen et al. 54.30% 70.91% 86.45% 64.47% 74.93% 78.91%
Our approach 69.72% 81.17% 95.10% 78.83% 79.89% 81.56%
F-measure
SELECT DISTINCT ?location_name ?street_address ?end_time
WHERE {?action :act :open .
?action tl:start ?start_time .
?action tl:end ?end_time .
?action :where ?location .
?location rdf:type :EvacuationClass .
?location rdfs:label ?location_name .
?location vcard:locality "Chiyoda-ku"@en .
?location vcard:street-address ?street_address .
FILTER(?start_time <= "2011-03-11T17:00:00"^^xsd:dateTime &&
?end_time >= "2011-03-11T17:00:00"^^xsd:dateTime &&
lang(?street_address) = "en" &&
lang(?location_name) = "en"
)
}
Fig. 8. An example query for looking up opening evacuation centers based on time and location
location_name
"Akihabara Washington Hotel"@en
street_addresss
"1-8-3 Sakuma-cho, Kanda"@en
start_time
2011-03-11T16:00:00
end_time
2011-03-12T09:00:00
Fig. 9. An example result of opening evacuation center
5.2
Timeline Action Network
We used SPARQL to make RDF queries to evaluate our timeline action network. For
example, Figure 8 shows the query that looks up an opening evacuation center based on
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