Ehud Reiter

Computational Interpretations of the Gricean Maxims in the Generation of Referring Expressions

We examine the problem of generating definite noun phrases that are appropriate referring expressions; that is, noun phrases that (a) successfully identify the intended referent to the hearer whilst (b) not conveying to him or her any false conversational implicatures (Grice, 1975). We review several possible computational interpretations of the conversational implicature maxims, with different computational costs, and argue that the simplest may be the best, because it seems to be closest to what human speakers do. We describe our recommended algorithm in detail, along with a specification of the resources a host system must provide in order to make use of the algorithm, and an implementation used in the natural language generation component of the IDAS system.

Building applied natural language generation systems

In this article, we give an overview of Natural Language Generation (NLG) from an applied system-building perspective. The article includes a discussion of when NLG techniques should be used; suggestions for carrying out requirements analyses; and a description of the basic NLG tasks of content determination, discourse planning, sentence aggregation, lexicalization, referring expression generation, and linguistic realisation. Throughout, the emphasis is on established techniques that can be used to build simple but practical working systems now. We also provide pointers to techniques in the literature that are appropriate for more complicated scenarios.

Choosing words in computer-generated weather forecasts

One of the main challenges in automatically generating textual weather forecasts is choosing appropriate English words to communicate numeric weather data. A corpus-based analysis of how humans write forecasts showed that there were major differences in how individual writers performed this task, that is, in how they translated data into words. These differences included both different preferences between potential near-synonyms that could be used to express information, and also differences in the meanings that individual writers associated with specific words. Because we thought these differences could confuse readers, we built our SumTime-Mousam weather-forecast generator to use consistent data-to-word rules, which avoided words which were only used by a few people, and words which were interpreted differently by different people. An evaluation by forecast users suggested that they preferred SumTime-Mousams texts to human-generated texts, in part because of better word choice; this may be the first time that an evaluation has shown that nlg texts are better than human-authored texts.

Connecting language to the world

1 Language in the World How does language relate to the non-linguistic world? If an agent is able to communicate linguistically and is also able to directly perceive and/or act on the world, how do perception, action, and language interact with and influence each other? Such questions are surely amongst the most important in Cognitive Science and Artificial Intelligence (AI). Language, after all, is a central aspect of the human mind ‐ indeed it may be what distinguishes us from other species. There is sometimes a tendency in the academic world to study language in isolation, as a formal system with rules for well-constructed sentences; or to focus on how language relates to formal notations such as symbolic logic. But language did not evolve as an isolated system or as a way of communicating symbolic logic; it presumably evolved as a mechanism for exchanging information about the world, ultimately providing the medium for cultural transmission across generations. Motivated by these observations, the goal of this special issue is to bring together research in AI that focuses on relating language to the physical world. Language is of course also used to communicate about non-physical referents, but the ubiquity of physical metaphor in language [21] suggests that grounding in the physical world provides the foundations of semantics.

Lessons from a failure: generating tailored smoking cessation letters

STOP is a Natural Language Generation (NLG) system that generates short tailored smoking cessation letters, based on responses to a four-page smoking questionnaire. A clinical trial with 2553 smokers showed that STOP was not effective; that is, recipients of a non-tailored letter were as likely to stop smoking as recipients of a tailored letter. In this paper we describe the STOP system and clinical trial. Although it is rare for AI papers to present negative results, we believe that useful lessons can be learned from STOP. We also believe that the AI community as a whole could benefit from considering the issue of how, when, and why negative results should be reported; certainly a major difference between AI and more established fields such as medicine is that very few AI papers report negative results.

An Architecture for Data-to-Text Systems

I present an architecture for data-to-text systems, that is NLG systems which produce texts from non-linguistic input data; this essentially extends the architecture of Reiter and Dale (2000) to systems whose input is raw data instead of AI knowledge bases. This architecture is being used in the BabyTalk project, and is based on experiences in several projects at Aberdeen; it also seems to be compatible with many data-to-text systems developed elsewhere. It consists of four stages which are organised in a pipeline: Signal Analysis, Data Interpretation, Document Planning, and Microplanning and Realisation.

AUTOMATIC-GENERATION OF TECHNICAL DOCUMENTATION

Natural-language generation (NLG) techniques can be used to automatically produce technical documentation from a domain knowledge base and linguistic and contextual models. We discuss this application of NLG technology from both a technical and a usefulness (costs and benefits) perspective. This discussion is based largely on our experiences with the Intelligent Documentation Advisory System (IDAS) documentation-generation project, and the reactions that various interested people from industry have had to IDAS. We hope that this summary of our experiences with IDAS and the lessons we have learned from it will be beneficial for other researchers who wish to build technical documentation-generation systems.

A fast algorithm for the generation of referring expressions

We simplify previous work in the development of algorithms for the generation of referring expressions while at the same time taking account of psycholinguistic findings and transcript data. The result is a straightforward algorithm that is computationally tractable, sensitive to the preferences of human users, and reasonably domain-independent. We provide a specification of the resources a host system must provide in order to make use of the algorithm, and describe an implementation used in the IDAS system.

Choosing the content of textual summaries of large time-series data sets

Natural Language Generation (NLG) can be used to generate textual summaries of numeric data sets. In this paper we develop an architecture for generating short (a few sentences) summaries of large (100KB or more) time-series data sets. The architecture integrates pattern recognition, pattern abstraction, selection of the most significant patterns, microplanning (especially aggregation), and realisation. We also describe and evaluate SumTime-Turbine, a prototype system which uses this architecture to generate textualsummaries of sensor data from gas turbines.

From data to text in the Neonatal Intensive Care Unit: Using NLG technology for decision support and information management

Contemporary Neonatal Intensive Care Units collect vast amounts of patient data in various formats, making efficient processing of information by medical professionals difficult. Moreover, different stakeholders in the neonatal scenario, which include parents as well as staff occupying different roles, have different information requirements. This paper describes recent and ongoing work on building systems that automatically generate textual summaries of neonatal data. Our evaluation results show that the technology is viable and comparable in its effectiveness for decision support to existing presentation modalities. We discuss the lessons learned so far, as well as the major challenges involved in extending current technology to deal with a broader range of data types, and to improve the textual output in the form of more coherent summaries.