tailieunhanh - Báo cáo khoa học: "Contextual Preferences"

The validity of semantic inferences depends on the contexts in which they are applied. We propose a generic framework for handling contextual considerations within applied inference, termed Contextual Preferences. This framework defines the various context-aware components needed for inference and their relationships. Contextual preferences extend and generalize previous notions, such as selectional preferences, while experiments show that the extended framework allows improving inference quality on real application data. . | Contextual Preferences Idan Szpektor Ido Dagan Roy Bar-Haim Jacob Goldberger Department of Computer Science School of Engineering Bar-Ilan University Bar-Ilan University Ramat Gan Israel Ramat Gan Israel szpekti dagan barhair @ goldbej@ Abstract The validity of semantic inferences depends on the contexts in which they are applied. We propose a generic framework for handling contextual considerations within applied inference termed Contextual Preferences. This framework defines the various context-aware components needed for inference and their relationships. Contextual preferences extend and generalize previous notions such as se-lectional preferences while experiments show that the extended framework allows improving inference quality on real application data. 1 Introduction Applied semantic inference is typically concerned with inferring a target meaning from a given text. For example to answer Who wrote Idomeneo Question Answering QA systems need to infer the target meaning Mozart wrote Idomeneo from a given text Mozart composed Idomeneo Following common Textual Entailment terminology Giampic-colo et al. 2007 we denote the target meaning by h for hypothesis and the given text by t. A typical applied inference operation is matching. Sometimes h can be directly matched in t in the example above if the given sentence would be literally Mozart wrote Idomeneo . Generally the target meaning can be expressed in t in many different ways. Indirect matching is then needed using inference knowledge that may be captured through rules termed here entailment rules. In our example Mozart wrote Idomeneo can be inferred using the rule X compose Y X write Y . Recently several algorithms were proposed for automatically learning entailment rules and paraphrases viewed as bi-directional entailment rules Lin and Pantel 2001 Ravichandran and Hovy 2002 Shinyama et al. 2002 Szpektor et al. 2004 Sekine 2005 . A common practice is to try matching the structure of