jurafsky&martin_3rdEd_17 (1).pdf

Conceptual dependency primitive definition a trans

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conceptual dependency Primitive Definition A TRANS The abstract transfer of possession or control from one entity to another P TRANS The physical transfer of an object from one location to another M TRANS The transfer of mental concepts between entities or within an entity M BUILD The creation of new information within an entity P ROPEL The application of physical force to move an object M OVE The integral movement of a body part by an animal I NGEST The taking in of a substance by an animal E XPEL The expulsion of something from an animal S PEAK The action of producing a sound A TTEND The action of focusing a sense organ Figure 22.7 A set of conceptual dependency primitives. Below is an example sentence along with its CD representation. The verb brought is translated into the two primitives ATRANS and PTRANS to indicate that the waiter both physically conveyed the check to Mary and passed control of it to her. Note that CD also associates a fixed set of thematic roles with each primitive to represent the various participants in the action. (22.47) The waiter brought Mary the check. 9 x , y Atrans ( x ) ^ Actor ( x , Waiter ) ^ Ob ject ( x , Check ) ^ To ( x , Mary ) ^ Ptrans ( y ) ^ Actor ( y , Waiter ) ^ Ob ject ( y , Check ) ^ To ( y , Mary ) 22.9 AMR To be written 22.10 Summary Semantic roles are abstract models of the role an argument plays in the event described by the predicate. Thematic roles are a model of semantic roles based on a single finite list of roles. Other semantic role models include per-verb semantic role lists and proto-agent / proto-patient , both of which are implemented in PropBank , and per-frame role lists, implemented in FrameNet .
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394 C HAPTER 22 S EMANTIC R OLE L ABELING Semantic role labeling is the task of assigning semantic role labels to the con- stituents of a sentence. The task is generally treated as a supervised machine learning task, with models trained on PropBank or FrameNet. Algorithms generally start by parsing a sentence and then automatically tag each parse tree node with a semantic role. Semantic selectional restrictions allow words (particularly predicates) to post constraints on the semantic properties of their argument words. Selectional preference models (like selectional association or simple conditional proba- bility) allow a weight or probability to be assigned to the association between a predicate and an argument word or class. Bibliographical and Historical Notes Although the idea of semantic roles dates back to Panini, they were re-introduced into modern linguistics by (Gruber, 1965) and (Fillmore, 1966) and (Fillmore, 1968) . Fillmore, interestingly, had become interested in argument structure by studying Lucien Tesni`ere’s groundbreaking ´ El´ements de Syntaxe Structurale (Tesni`ere, 1959) in which the term ‘dependency’ was introduced and the foundations were laid for dependency grammar. Following Tesni`ere’s terminology, Fillmore first referred to argument roles as actants (Fillmore, 1966) but quickly switched to the term case , (see Fillmore (2003) ) and proposed a universal list of semantic roles or cases (Agent, Patient, Instrument, etc.), that could be taken on by the arguments of predicates.
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