tailieunhanh - Báo cáo khoa học: "TOWARDS A SELF-EXTENDING PARSER"

This p a p e r discusses an approach to incremental learning in natural language processing. The t e c h n i q u e of projecting and integrating semantic c o n s t r a i n t s to learn word definitions is analyzed as Implemented in the POLITICS system. E x t e n s i o n s and improvements of this technique are developed. The problem of generalizing existing word meanings and understanding metaphorical uses of words Is addressed In terms of semantic constraint Integration. | TOWARDS A SELF-EXTENDING PARSER Jaime G. Carbonell Department Of Computer Science Carnegie-Mellon University Pittsburgh PA 15213 Abstract This paper discusses an approach to Incremental learning In natural language processing. The technique of projecting and Integrating semantic constraints to learn word definitions Is analyzed as Implemented In the POLITICS system. Extensions and Improvements of this technique are developed. The problem of generalizing existing word meanings and understanding metaphorical uses of words Is addressed In terms of semantic constraint Integration. 1. Introduction Natural language analysis like most other subfields of Artificial Intelligence and Computational Linguistics suffers from the fact that computer systems are unable to automatically better themselves. Automated learning la considered a very difficult problem especially when applied to natural language understanding. Consequently little effort has been focused on this problem. Some pioneering work In Artificial Intelligence such as AM 1 and Winston s learning system 2 strove to learn or discover concept descriptions In well-defined domains. Although their efforts produced Interesting Ideas and techniques these techniques do not fully extend to a domain as complex as natural language analysis. Rather than attempting the formidable task of creating a language learning system I will discuss techniques for Incrementally Increasing the abilities of a flexible language analyzer. There are many tasks that can be considered Incremental language learning . Initially the learning domain Is restricted to learning the meaning of new words and generalizing existing word definitions. There are a number of . techniques and combinations of these techniques capable of exhibiting Incremental learning behavior. I first discuss FOULUP and POLITICS two programs that exhibit a limited capability for Incremental word learning. Secondly the technique of semantic constraint projection and Integration