A shallow processing approach to anaphor resolution

The thesis describes an investigation of the feasibility of resolving anaphors in natural language texts by means of a "shallow processing" approach which exploits knowledge of syntax, semantics and local focussing as heavily as possible; it does not rely on the presence of large amounts of world or domain knowledge, which are notoriously hard to process accurately. The ideas reported are implemented in a program called SPAR (Shallow Processing Anaphor Resolver), which resolves anaphoric and other linguistic ambiguities in simple English stories and generates sentence-by-sentence paraphrases that show what interpretations have been selected. Input to SPAR takes the form of semantic structures for single sentences constructed by Boguraev's English analyser. These structures are integrated into a network-style text representation as processing proceeds. To achieve anaphor resolution, SPAR combines and develops several existing techniques, most notably Sidner's theory of local focussing and Wilks' "preference semantics" theory of semantics and common sense inference. Consideration of the need to resolve several anaphors in the same sentence results in Sidner's framework being modified and extended to allow focus-based processing to interact more flexibly with processing based on other types of knowledge. Wilks' treatment of common sense inference is extended to incorporate a wider range of types of inference without jeopardizing its uniformity and simplicity. Further, his primitive-based formalism for word sense meanings is developed in the interests of economy, accuracy and ease of use. Although SPAR is geared mainly towards resolving anaphors, the design of the system allows many non-anaphoric (lexical and structural) ambiguities that cannot be resolved during sentence analysis to be resolved as a by-product of anaphor resolution

Fallible Rationalism and Machine Translation

Approaches to MT have been heavily influenced by changing trends in the philosophy of language and mind. Because of the artificial hiatus which followed the publication of the ALPAC Report, MT research in the 1970s and early 1980s has had to catch up with major developments that have Occurred in linguistic and philosophical thinking; currently, MT seems to be uncritically loyal to a paradigm of thought about language which is rapidly losing most of its adherents i departments of linguistics and philosophy. I argue, both in theoretical terms and by reference to empirical research on a particular translation problem, that the PopperJan "fallible rationalist" view of mental processes which is winning acceptance as a more sophisticated alternative to Chomskyan "determin- istic rationalism" should lead MT researchers to redefine their goals and to adopt certain currently -neglected techniques in trying to achieve those goals