tailieunhanh - manning schuetze statisticalnlp phần 3

Ngôn Ngữ Essentials b. Mary đã giúp các hành khách khác ra khỏi buồng lái. Người đàn ông đã hỏi cô ấy để giúp anh ta vì chấn thương bàn chân của mình. Các quan hệ Anaphoric giữ giữa các cụm danh từ tham chiếu đến cùng một người hoặc điều. | 112 3 Linguistic Essentials b. Mary helped the other passenger out of the cab. The man had asked her to help him because of his foot injury. Anaphoric relations hold between noun phrases that refer to the same person or thing. The noun phrases Peter and He in sentence and the other passenger and The man in sentence refer to the same INFORMATION person. The resolution of anaphoric relations is important for informaEXTRACTION tion extraction. In information extraction we are scanning a text for a specific type of event such as natural disasters terrorist attacks or corporate acquisitions. The task is to identify the participants in the event and other information typical of such an event for example the purchase price in a corporate merger . To do this task well the correct identification of anaphoric relations is crucial in order to keep track of the participants. Hurricane Hugo destroyed 20 000 Florida homes. At an estimated cost of one billion dollars the disaster has been the most costly in the state s history. If we identify Hurricane Hugo and the disaster as referring to the same entity in mini-discourse we will be able to give Hugo as an answer to the question Which hurricanes caused more than a billion dollars worth of damage Discourse analysis is part of the study of how knowledge about the world and language conventions interact with literal meaning. Anaphoric relations are a pragmatic phenomenon since they are constrained by world knowledge. For example for resolving the relations in discourse it is necessary to know that hurricanes are disasters. Most areas of pragmatics have not received much attention in Statistical NLP both because it is hard to model the complexity of world knowledge with statistical means and due to the lack of training data. Two areas that are beginning to receive more attention are the resolution of anaphoric relations and the modeling of speech acts in dialogues. Other Areas Linguistics is traditionally subdivided into .