Abstract

The basic structure of MORPHS was described at the Fifth Cranfield Conference when emphasis was placed on the automatic root finding/role applying procedures based on linguistic principles. This skeleton remains, but it has since been clothed with relatively complex, iterative search strategies. The major strategy employs the normal Boolean operators either in the form of strings without bracketing or in the form of marked steps. The latter enables back-tracking to be carried out. Recycling of search strategies is only limited by the number of tracks available for storing searches on the disc unit before over-writing takes place. Printing-out does not interfere with searching. A second strategy treats a string of keywords as a compound word; if it fails to find it the compound is then decomposed into its elements, which are then automatically treated as a string connected by AND logic; incidentally this technique also acts as a bracketing technique, but without the inconvenience of physical brackets. SDI procedures have been evolved as a by-product.

Ultimately it is hoped that it may be possible to develop a degree of question answering ability: this could be achieved in several ways. The simplest (based on the modifying effect of certain interrogatory elements, e.g. WHO) has been evaluated and works. With the exception of the SDI system which employs 16k, all of the above systems were developed and originally operated in 12k of core with 16 bit words on a minicomputer. Nevertheless, despite this severe restriction on space it has been possible to implement searching strategies for dedicated on-line searching which are at least as good and in many ways better (e.g. automatic synonym substitution) than many employed in the large time-sharing systems currently available.

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