5978989
Asymmetry in Parsing and Generating with Unification Grammars: Case Studies from ELU
Recent developments in generation algorithms have enabled work in unification-based computational linguistics to approach more closely the ideal of grammars as declarative statements of linguistic facts, neutral between analysis and synthesis. From this perspective, however, the situation is still far from perfect; all known methods of generation impose constraints on the grammars they assume.We briefly consider a number of proposals for generation, outlining their consequences for the form of grammars, and then report on experience arising from the addition of a generator to an existing unification environment. The algorithm in question (based on that of Shieber et al. (1989)), though among the most permissive currently available, excludes certain classes of parsable analyses.
45352
A Practical Approach to Multiple Default Inheritance for Unification-Based Lexicons
This paper describes a unification-based lexicon system for NLP applications that incorporates mechanisms for multiple default inheritance. Such systems are intractable in the general case---the approach adopted here places a number of restrictions on the inheritance hierarchy in order to remove some of the sources of complexity while retaining more desirable properties. Implications of the design choices are discussed, comparisons are drawn with related work in computational linguistics and AI, and illustrative examples from the lexicons of German and English are given.
1627677
High Precision Extraction of Grammatical Relations
A parsing system returning analyses in the form of sets of grammatical relations can obtain high precision if it hypothesises a particular grammatical relation only when it is certain that the relation is correct. We operationalise this technique -in a statistical parser using a manually-developed wide-coverage grammar of English - by only returning relations that form part of all analyses licensed by the grammar. We observe an increase in precision from 75% to over 90% (at the cost of a reduction in recall) on a test corpus of naturally-occurring text.
9629533
The Automatic Acquisition of Verb Subcategorisations and Their Impact on the Performance of an HPSG Parser
We describe the automatic acquisition of a lexicon of verb subcategorisations from a domain-specific corpus, and an evaluation of the impact this lexicon has on the performance of a “deep”, HPSG parser of English. We conducted two experiments to determine whether the empirically extracted verb stems would enhance the lexical coverage of the grammar and to see whether the automatically extracted verb subcategorisations would result in enhanced parser coverage. In our experiments, the empirically extracted verbs enhance lexical coverage by 8.5%. The automatically extracted verb subcategorisations enhance the parse success rate by 15% in theoretical terms and by 4.5% in practice. This is a promising approach for improving the robustness of deep parsing.
12738746
Software support for practical grammar development
Even though progress in theoretical linguistics does not necessarily rely on the construction of working programs, a large proportion of current research in syntactic theory is facilitated by suitable computational tools. However, when natural language processing applications seek to draw on the results from new developments in theories of grammar, not only the nature of the tools has to change, but they face the challenge of reconciling the seemingly contradictory requirements of notational perspicuity and efficiency of performance. In this paper, we present a comparison and an evaluation of a number of software systems for grammar development, and argue that they are inadequate as practical tools for building wide-coverage grammars. We discuss a number of factors characteristic of this task, demonstrate how they influence the design of a suitable software environment, and describe the implementation of a system which has supported efficient development of a large computational grammar of English.
1954
Corpus Annotation for Parser Evaluation
We describe a recently developed corpus annotation scheme for evaluating parsers that avoids shortcomings of current methods. The scheme encodes grammatical relations between heads and dependents, and has been used to mark up a new publicdomain corpus of naturally occurring English text. We show how the corpus can be used to evaluate the accuracy of a robust parser, and relate the corpus to extant resources.
7151657
Making use: a design representation
14643603
Making use is more than a matter of task analysis
I am pleased and honored that such an impressive group of commentators considered my book Making Use (Carroll, 2000) worthy of discussion and analysis. I would not expect, nor even prefer really, to have everyone agree with me. What would bother me, what would bother any author, is to not be read at all. Dan Diaper’s critical review and the commentaries by David Benyon/Catriona Macaulay, Tom Carey, and Fabio Paterno, will help to make that less likely! Many important themes are raised in Diaper (2002) review and in the commentaries. In this response I want to concentrate on refining a few of the main issues and distinctions. First, I briefly consider contrasts in values. I think that preferences for scenario-based design versus traditional task analytic methods reflect differences in the underlying world views and values of designers and researchers. To some extent, therefore, the issues in this discussion are not just technical, but paradigmatic and moral. Second, I consider the state of design practices in HCI and its implications for where onus lies in contemporary methodological argumentation and for what sorts of data are pertinent and required to address outstanding methodological issues. Finally, I consider the question of how task analysis, in the sense of structured task decomposition, might be reconstructed in the emerging paradigm of scenario-based design.
18081961
Designing our town: MOOsburg
MOOsburg is a community-oriented multi-user domain. It was created to enrich the Blacksburg Electronic Village (BEV) by providing real-time, situated interaction and a place-based model for community information. Three versions of MOOsburg have been developed: a classic text-based MOO, a MOO extended to drive a Web-browser, and a Java-based system. The most recent version of MOOsburg is fundamentally different from classic MOOs, supporting distributed system development and management and a direct manipulation approach to navigation. We are currently developing a variety of community-oriented applications, including a virtual science fair and a dispersed natural history museum.
148806746
Human-computer interaction: psychology as a science of design.
14571844
The process of ISD methodology selection and use: a case study
This paper provides empirically-based explanations for the observed low, and partial, use of information systems development (ISD) methodologies. The research reported in this paper examines the process of methodology selection and use in an intensive field study of the early stages of systems development and notes ongoing adaptation of methodologies in response to changing contingencies. The paper concludes that, in many circumstances, methodology adaptation is a necessary part of successful systems development. It also suggests that deeper understanding of the attitudes of different stakeholders to selecting and using ISD methodologies may help to explain this adaptation.