京大黒橋・河原研で開催されたEMNLP読み会の資料。
紹介した論文は、
Distinguishing Past, On-going, and Future Events: The EventStatus Corpus
Ruihong Huang; Ignacio Cases; Dan Jurafsky; Cleo Condoravdi; Ellen Riloff
1. Distinguishing Past, On-going,
and Future Events:
The EventStatus Corpus
Ruihong Huang, Ignacio Cases, Dan Jurafsky,
Cleo Condoravdi and Ellen Riloff
紹介する人: 萩行 正嗣 (2014年卒)
ウェザーニューズ
EMNLP2016読み会@京大
3. Outline of EventStatus Corpus (in Section 2)
•文中のEvent(今回はcivil unrestのみ)に対して、
Past、On-Going、Future (Planned、Alert、Possible)を
アノテーション
• Past: Today’s demonstration ended without violence.
• On-Going: Negotiations continue with no end in sight for
the 2 week old strike.
• Future Planned: 77 percent of German steelworkers voted
to strike to raise their wages.
• Future Alert: Farmers have threatened to hold
demonstrations on Monday.
• Future Possible: The military is preparing for possible
protests at the G8 summit.
EMNLP2016読み会@京大
4. Annotation Scheme (in Section 2.1)
1. civil unrest に関するkeywordを含むnew storyを
抽出
• 2954 stories, 5085 sentences
2. 各文がspecific eventを指すmentionを含むかを
アノテーション
• keywordマッチでは語義曖昧性やgeneric descriptionで、
specific event以外も入る(e.g., “Protests are often
facilitated by ...)
• 2492 sentences (49%)がspecific eventあり (κ = 0.84)
3. 文中の各keywordにevent statusラベルをアノ
テーション(5種の時間ラベル+ Not Eventラベル)
• κ=0.78
• 3人ともバラバラは83個(2.9%)あった
EMNLP2016読み会@京大
5. Corpus Properties (in Section 2.1 and 2.2)
EMNLP2016読み会@京大
Non-finite form
tenseやaspectの情報が使え
ないので、時間情報のラベル
付けが難しい
6. Future Oriented Verbs (in Section 2.3) (1)
•“threatened”や”fear”のように、future eventを想定
した動詞をfuture oriented verbsと定義
• Mental activity (“anticipate”, “expect”)
Affective (“fear”, “worry”), planning(“plan”, “prepare”),...
•2つのheuristicでfuture oriented verbsを集める
1. matrix verb(母型動詞)がpast tense + complement
event(補語)が未来の時間表現で修飾されている
• The union planned to strike next week.
2. 条件節で修飾されたmatrix verb
• The union threatened to strike if their appeal was
rejected
• 双方で出現したmatrix verbをfuture oriented verbsとする
EMNLP2016読み会@京大
11. CNN’s Improvement Cases (in Section 6)
•Raising the possibility of a strike on New Year’s Eve,
the president of New York City’s largest union is
calling for a 30 percent raise over three years. (FU)
•The lockout was announced in the wake of a go-
slow and partial strike by the union since July 12
after management turned down its demand. (OG)
CNNは周辺の手掛りとの構成性をうまく捉えられ
ている?(“possibility”、”since”)
EMNLP2016読み会@京大
12. Error Analysis (in Section 6)
•discourseの情報が必要 (26/50)
• Chavez also said he discussed the strike with UN Secretary
General Kofi Annan and told him the strike organizers
were “terrorists.” (OG) (“double access” ambiguity)
• Students and teachers protest over education budget (PA)
•時間の手掛りが構成的かつ離れている (9/50)
• Protesters on Saturday also occupied two gymnastics halls
near Gorleben which are to be used as accommodation
for police. They were later forcibly dispersed by
policemen. (PA)
•ローカルな情報で解けるはずだが誤答 (15/50)
• Eastern leaders have grown weary of the protest
movement led mostly by Aymara. (OG)
EMNLP2016読み会@京大
赤字は手がかり
(論文に明記されていな
いため、萩行による推測)