Jerry R. Hobbs

DAML-S: Web Service Description for the Semantic Web

In this paper we present DAML-S, a DAML+OIL ontology for describing the properties and capabilities of Web Services. Web Services - Web-accessible programs and devices - are garnering a great deal of interest from industry, and standards are emerging for low-level descriptions of Web Services. DAML-S complements this effort by providing Web Service descriptions at the application layer, describing what a service can do, and not just how it does it. In this paper we describe three aspects of our ontology: the service profile, the process model, and the service grounding. The paper focuses on the grounding, which connects our ontology with low-level XML-based descriptions of Web Services.

Coherence and coreference

Coherence in conversations and in texts can be partially characterized by a set of coherence relations, motivated ultimately by the speakers or writers need to be understood. In this paper, formal definitions are given for several coherence relations, based on the operations of an inference system; that is, the relations between successive portions of a discourse are characterized in terms of the inferences that can be drawn from each. In analyzing a discourse, it is frequently the case that we would recognize it as coherent, in that it would satisfy the formal definition of some coherence relation, if only we could assume certain noun phrases to be coreferential. In such cases, we will simply assume the identity of the entities referred to, in what might be called a “petty conversational implicature,” thereby solving the coherence and coreference problems simultaneously. Three examples of different kinds of reference problems are presented. In each, it is shown how the coherence of the discourse can be recognized, and how the reference problems are solved, almost as a by-product, by means of these petty conversational implicatures.

Resolving Pronoun References

Abstract Two approaches to the problem of resolving pronoun references are presented. The first is a naive algorithm that works by traversing the surface parse trees of the sentences of the text in a particular order looking for noun phrases of the correct gender and number. The algorithm clearly does not work in all cases, but the results of an examination of several hundred examples from published texts show that it performs remarkably well. In the second approach, it is shown how pronoun solution can be handled in a comprehensive system for semantic analysis of English texts. The system is described, and it is shown in a detailed treatment of several examples how semantic analysis locates the antecedents of most pronouns as a by-product. Included are the classic examples of Winograd and Charniak.

An ontology of time for the semantic web

In connection with the DAML project for bringing about the Semantic Web, an ontology of time is being developed for describing the temporal content of Web pages and the temporal properties of Web services. This ontology covers topological properties of instants and intervals, measures of duration, and the meanings of clock and calendar terms.

Ontological Promiscuity

To facilitate work in discourse interpretation, the logical form of English sentences should be both close to English and syntactically simple. In this paper I propose a logical notation which is first-order and nonintensional, and for which semantic translation can be naively compositional. The key move is to expand what kinds of entities one allows in ones ontology, rather than complicating the logical notation, the logical form of sentences, or the semantic translation process. Three classical problems - opaque adverbials, the distinction between de re and de dicto belief reports, and the problem of identity in intensional contexts - are examined for the difficulties they pose for this logical notation, and it is shown that the difficulties can be overcome. The paper closes with a statement about the view of semantics that is presupposed by this approach.

SRI International FASTUS system: MUC-6 test results and analysis

SRI International participated in the MUC-6 evaluation using the latest version of SRIs FASTUS system [1]. The FASTUS system was originally developed for participation in the MUC-4 evaluation [3] in 1992, and the performance of FASTUS in MUC-4 helped demonstrate the viability of finite state technologies in constrained natural-language understanding tasks. The system has undergone significant revision since MUC-4, and it is safe to say that the current system does not share a single line of code with the original. The fundamental ideas behind FASTUS, however, are retained in the current system: an architecture consisting of cascaded finite state transducers, each providing an additional level of analysis of the input, together with merging of the final results.

Interpreting discourse: Coherence and the analysis of ethnographic interviews

(1982). Interpreting discourse: Coherence and the analysis of ethnographic interviews. Discourse Processes: Vol. 5, No. 1, pp. 1-32.

Conversation as Planned Behavior

In this paper, planning models developed in artificial intelligence are applied to the kind of planning that must be carried out by participants in o conversation. A planning mechanism is defined, and a short fragment of o free-flowing videotaped conversation is described. The bulk of the paper is then devoted to an attempt to understand the conversation in terms of the planning mechanism. This microanalysis suggests ways in which the planning mechanism must be ougmented, and reveals several important conversational phenomena that deserve further investigation.

The generic information extraction system

An information extraction system is a cascade of transducers or modules that at each step add structure and often lose information, hopefully irrelevant, by applying rules that are acquired manually and/or automatically.

Two principles of parse preference

The DIALOGIC system for syntactic analysis and semantic translation has been under development for over ten years, and during that time it has been used in a number of domains in both database interface and message-processing applications. In addition, it has been tested on a number of sentences of linguistic interest. Built into the system are facilities for ranking parses according to syntactic and selectional considerations, and over the years, as various kinds of ambiguity have become apparent, heuristics have been devised for choosing the preferred parses. Our aim in this paper is first to present a compendium of many of these heuristics and second to propose two principles that seem to underlie the heuristics. The first will be useful to researchers engaged in building grammars of similarly broad coverage. The second is of psychological interest and may be a guide for estimating parse preferences for newly discovered ambiguities for which we lack the experience to decide among on a more empirical basis.