IR-NLI : An Expert Natural Language Interface to Online Data Bases

IR-NLI : AN EXPERT NATURAL LANGUAGE INTERFACE TO ONLINE DATA BASES (o) Giovanni Guida , Carlo Tasso (*) Istituto di Matematica, Informatica e Sistemistica Universit~ di Udine Via Antonini,8 - 33100 Udine, Italy ABSTRACT Constructing natural language interfaces to computer systems often requires achievment of ad- vanced reasoning and expert capabilities in addition to basic natural language understanding. In this pa- per the above issues are faced in the frame of an actual application concerning the design of a natu- ral language interface for the access to online in- formation retrieval systems. After a short discus - sion of the peculiarities of this application, which requires both natural language understanding and reasoning capabilities, the general architecture and fundamental design criteria of a system presently being developed at the University of Udine are then presented, The system, named IR-NLi, is aimed at al- lowing non-technical users to directly access through natural language the services offered by online da- ta bases. Attention is later focused on the basic functions of IR-NLI, namely, understanding and dia- logue, strategy generation, and reasoning. Knowledge represenetation methods and "~igorithms adopted are also illustar~ed. A short example of interaction with IR-LNT~I is presented. Perspectives and direcZions for future research are also discussed. I INTRODUCTION Natural language processing has developed in the last years in several directions that often go far beyond the original goal of mapping natural laua- ~uage expressions into formal internal representa - zions. ?roblems concerned with discourse modeling, reasoning about beliefs, knowledge and wants of speaker and hearer, expiicitely dealing with goals, plans, and speech acts are only a few of the topics ~f current interest in the field. This paper is con- :erned with one ~spect of natural language processing that we name here reasoning, it is intended as a ba- sic • ctivity in natural language comprehension that is aimed at capturing spes/~er's goals and inten - tions that often lie behind the mere literal mea- ning of the utterance. In this work we explore the main implications of reasoning in the frame of an acttu&l application which is concerned with the na- tttral language acees to online information retrie- val services (Politt,1981; Waterman,1978). In particular, we shall present the detailed design of a system, named IR-NLI (Information Re- trieval Natural Language Interface), that is being developed at the University of Udine and we shall discuss its main original features. The topic of natural language reasoning is first shortly i!lu- strated from a conceptual point of view and compa- red to related proposals. The main features of the chosen application domain are then described and the specifications of ~R-NLI are stated. We later turn to the architecture of the system and we go fturther into a detailed account of the structure of its knowledge bases and of its mode of operation. Particular attention id devoted to the three funda- mental modules STARTEGY GENERATOR, REASONING, ~nd UNDERSATNDING AND DIALOGUE. A sample search session with IR-NLI concludes the illustarion of the pro- ject. A …

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