tailieunhanh - Báo cáo khoa học: "Never Look Back: An Alternative to Centering Michael Strube"

I propose a model for determining the hearer's attentional state which depends solely on a list of salient discourse entities (S-list). The ordering among the elements of the S-list covers also the function of the backward-looking center in the centering model. The ranking criteria for the S-list are based on the distinction between hearer-old and hearer-new discourse entities and incorporate preferences for inter- and intra-sentential anaphora. | Never Look Back An Alternative to Centering Michael Strube IRCS - Institute for Research in Cognitive Science University of Pennsylvania 3401 Walnut Street Suite 400A Philadelphia PA 19104 strube@ Abstract I propose a model for determining the hearer s at-tentional state which depends solely on a list of salient discourse entities S-list . The ordering among the elements of the S-list covers also the function of the backward-looking center in the centering model. The ranking criteria for the S-list are based on the distinction between hearer-old and hearer-new discourse entities and incorporate preferences for inter- and intra-sentential anaphora. The model is the basis for an algorithm which operates incrementally word by word. 1 Introduction I propose a model for determining the hearer s at-tentional state in understanding discourse. My proposal is inspired by the centering model Grosz et al. 1983 1995 and draws on the conclusions of Strube Hahn s 1996 approach for the ranking of the forward-looking center list for German. Their approach has been proven as the point of departure for a new model which is valid for English as well. The use of the centering transitions in Brennan et al. s 1987 algorithm prevents it from being applied incrementally cf. Kehler 1997 . In my approach I propose to replace the functions of the backward-looking center and the centering transitions by the order among the elements of the list of salient discourse entities S-list . The S-list ranking criteria define a preference for hearer-old over hearer-new discourse entities Prince 1981 generalizing Strube Hahn s 1996 approach. Because of these ranking criteria I can account for the difference in salience between definite NPs mostly hearer-old and indefinite NPs mostly hearer-new . The S-list is not a local data structure associated with individual utterances. The S-list rather describes the attentional state of the hearer at any given point in processing a discourse. The