We describe the design and implementation of the Glue-Nail database system. The Nail language is a purely declarative query language; Glue is a procedural language used for non-query activities. The two languages combined are sufficient to write a complete application. Nail and Glue code both compile into the target language IGlue. The Nail compiler uses variants of the magic sets algorithm, and supports well-founded models. Static optimization is performed by the Glue compiler using techniques that include peephole methods and data flow analysis. The IGlue code is executed by the IGlue interpreter, which features a run-time adaptive optimizer. The three optimizers each deal with separate optimization domains, and experiments indicate that an effective synergism is achieved. The Glue-Nail system is largely complete and has been tested using a suite of representative applications.

One problem for the generation of natural language text is determining when to use a sequence of simple sentences and when a single complex one is more appropriate. In this paper, we show how focus of attention is one factor that influences this decision and describe its implementation in a system that generates explanations for a student advisor expert system. The implementation uses tests on functional information such as focus of attention within the Prolog definite clause grammar formalism to determine when to use complex sentences, resulting in an efficient generator that has the same benefits as a functional grammar system.

Sperry Univac is developing a linguistically oriented system for locating key information-carrying words in conversational speech. The system first analyzes the speech acoustically, providing information on bandlimited energies and fundamental and formant frequencies. A prosodic analysis then indicates the location of syllables. Finally, a phonetic word verification technique is exercised on each syllable. Prestored acoustic properties characteristic of each phonetic segment of each keyword are compared against the incoming acoustic properties found at appropriate locations anchored within and around the syllables. Acoustic-phonetic parameter alignments exhibiting great similarity are announced as likely keyword occurrences. Current results are presented for this system, which is being developed and tested on noisy, bandlimited, conversational speech from a large and diverse speaker population.