J. R. Kennaway

Term graph rewriting

Graph rewriting (also called reduction) as defined in Wadsworth [1971] was introduced in order to be able to give a more efficient implementation of functional programming languages in the form of lambda calculus or term rewrite systems: identical subterms are shared using pointers.

The development of language processing support for the ViSiCAST project

ViSiCAST is a major new project funded by the European Union, aiming to provide improved access to services and facilities for deaf citizens through sign language presented by a virtual human, or avatar. We give here an outline of the project, and describe early work in the area of linguistics and language processing. This work covers two distinct but related areas: first, the development of an XML-compliant notation for deaf sign language gestures, which can be used to drive the signing avatar; and, second, the development of a framework supporting the translation of natural language text into this gesture-orientated notation.

Linguistic modelling and language-processing technologies for Avatar-based sign language presentation

Sign languages are the native languages for many pre-lingually deaf people and must be treated as genuine natural languages worthy of academic study in their own right. For such pre-lingually deaf, whose familiarity with their local spoken language is that of a second language learner, written text is much less useful than is commonly thought. This paper presents research into sign language generation from English text at the University of East Anglia that has involved sign language grammar development to support synthesis and visual realisation of sign language by a virtual human avatar. One strand of research in the ViSiCAST and eSIGN projects has concentrated on the generation in real time of sign language performance by a virtual human (avatar) given a phonetic-level description of the required sign sequence. A second strand has explored generation of such a phonetic description from English text. The utility of the conducted research is illustrated in the context of sign language synthesis by a preliminary consideration of plurality and placement within a grammar for British Sign Language (BSL). Finally, ways in which the animation generation subsystem has been used to develop signed content on public sector Web sites are also illustrated.

Providing signed content on the Internet by synthesized animation

Written information is often of limited accessibility to deaf people who use sign language. The eSign project was undertaken as a response to the need for technologies enabling efficient production and distribution over the Internet of sign language content. By using an avatar-independent scripting notation for signing gestures and a client-side web browser plug-in to translate this notation into motion data for an avatar, we achieve highly efficient delivery of signing, while avoiding the inflexibility of video or motion capture. Tests with members of the deaf community have indicated that the method can provide an acceptable quality of signing.

Towards an intermediate language based on graph rewriting

Lean is an experimental language for specifying computations in terms of graph rewriting. It is based on an alternative to Term Rewriting Systems (TRS) in which the terms are replaced by graphs. Such a Graph Rewriting System (GRS) consists of a set of graph rewrite rules which specify how a graph may be rewritten. Besides supporting functional programming, Lean also describes imperative constructs and allows the manipulation of cyclic graphs. Programs may exhibit non-determinism as well as parallelism. In particular, Lean can serve as an intermediate language between declarative languages and machine architectures, both sequential and parallel.

LEAN: An intermediate language based on graph rewriting

Abstract LEAN is an exaerimental language for specifying computations in terms of graph rewriting. It is based on an alternative to Term Rewriting Systems (TRS) in which the terms are replaced by graphs. Such a Graph Rewriting System (GRS) consists of a set of graph rewrite rules which specify how a graph may be rewritten. Besides supporting functional programming, LEAN also describes imperative constructs and allows the manipulation of cyclic graphs. Programs may exhibit non-determinism as well as parallelism. In particular, LEAN can serve as an intermediate language between declarative languages and machine architectures, both sequential and parallel. This paper is a revised version of a paper by the same authors which was presented at the ESPRIT, PARLE, Conference in Eindhoven, The Netherlands, June 1987.