Measuring semantic complexity

We define {\em semantic complexity} using a new concept of {\em meaning automata}. We measure the semantic complexity of understanding of prepositional phrases, of an "in depth understanding system", and of a natural language interface to an on-line calendar. We argue that it is possible to measure some semantic complexities of natural language processing systems before building them, and that systems that exhibit relatively complex behavior can be built from semantically simple components.Comment: 11 pp. Latex.. To appear in Proc. BISFAI'95, The Fourth Bar-Ilan Symposium on Foundations of Artificial Intelligence, June 20-22, 1995, Ramat-Gan and Jerusalem, Israel. Correspondence to [email protected]

Natural Language Processing: Structure and Complexity

We introduce a method for analyzing the complexity of natural language processing tasks, and for predicting the difficulty new NLP tasks. Our complexity measures are derived from the Kolmogorov complexity of a class of automata --- {\it meaning automata}, whose purpose is to extract relevant pieces of information from sentences. Natural language semantics is defined only relative to the set of questions an automaton can answer. The paper shows examples of complexity estimates for various NLP programs and tasks, and some recipes for complexity management. It positions natural language processing as a subdomain of software engineering, and lays down its formal foundation.Comment: 8 pp. Latex (documentstyle[ijcai89,named]). In: "Proc. SEKE'96, 8th Int. Conf. on Software Engineering and Knowledge Engineering", Lake Tahoe, 1996, pages 595-60

A Robust Approach For Handling Oral Dialogues

Present limits of speech recognition and understanding in the context of free spoken language (although wit/, a limited vocabulary) have perverse el/bets on the flow of the dialogue wiIh a system. Typically a non robut dialogue manager will fail to face with these limits and conversations will often be a failure. This paper presents some possibilities of a structural approach for handling communication failures in task-oriented oral dialogues. Several types o.f communicatiot, failures are presented and explained. They must be dealt with by the dialogue manager if we strike to have a robert system. The exposed strategies for handling these failures are based on a structural approach of the conversation and are implemented in the SUNDlAL .system. We first recall some aspects of the model and then describe the strategies for preventing anti repairing communication [ailurc in oral conversations with a s:vstem