Description of the LTG system used for MUC-7

Abstract

The basic building blocks in our muc system are reusable text handling tools which wehave been developing and using for a number of years at the Language Technology Group. They are modular tools with stream input/output; each tooldoesavery speci c job, but can be combined with other tools in a unix pipeline. Di erent combinations of the same tools can thus be used in a pipeline for completing di erent tasks. Our architecture imposes an additional constraint on the input/output streams: they should have a common syntactic format. For this common format we chose eXtensible Markup Language (xml). xml is an o cial, simpli ed version of Standard Generalised Markup Language (sgml), simpli ed to make processing easier [3]. Wewere involved in the developmentofthexml standard, building on our expertise in the design of our own Normalised sgml (nsl) and nsl tool lt nsl [10], and our xml tool lt xml [11]. A detailed comparison of this sgml-oriented architecture with more traditional data-base oriented architectures can be found in [9]. A tool in our architecture is thus a piece of software which uses an api for all its access to xml and sgml data and performs a particular task: exploiting markup which has previously been added by other tools, removing markup, or adding new markup to the stream(s) without destroying the previously added