tailieunhanh - Báo cáo khoa học: "A CASE FOR RULE-DRIVEN SEMANTIC PROCESSING"

Canonical Level This intermediate level of representation usually consists of the verb itself, (or perhaps a more primitive semantic predicate chosen to represent the verb) and a list of possible roles, . arguments to the predicate. These roles correspond loosely to a union of the various semantic types indicated in the schemas. The schemas above could all easily map i n t o : SUPPORTS(l,2, ,). | A CASE FOR RULE-DRIVEN SEMANTIC PROCESSING Martha Palmer Department of Computer and Information Science University of Penneylanla INTRODUCTION The primary task of semantic processing Is to provide an appropriate mapping between the syntactic constituents of a parsed sentence and the arguments of the semantic predicates Implied by the verb. This Is known as the Alignment Problem. Levin Section One of this paper gives an overview of a generally accepted approach to semantic processing that goes through several levels of representation to achieve this mapping. Although somewhat Inflexible and cumbersome the different levels succeed In preserving the context sensitive Information provided by verb semantics. Section Two presents the author s rule-driven approach which Is more uniform and flexible yet still accommodates context sensitive constraints. This approach is based on general underlying principles for syntactic methods of Introducing semantic arguments and has Interesting Implications for linguistic theories about case. These Implications are dicussed In Section Three. A system that Implements this approach has been designed for and tested on pulley problem statements gathered from several physics text books. Palmer MULTI-STAGE SEMANTIC ANALYSIS A popular approach Woods Simmons Novak for assigning semantic roles to syntactic constituents can be described with three levels of representation - a schema level a canonical level and a predicate level. These levels are used to bridge the gap between the surface syntactic representation and the deep conceptual representation necessary for communicating with the Internal database. While the following description of these levels may not correspond to any one Implementation in particular It will give the flavor of the overall approach. Canonical Leve1 This Intermediate level of representation usually consists of the verb Itself or perhaps a more primitive semantic predicate chosen to represent the verb and a .