18711252
Grammar Compaction and Computation Sharing in Automata-based Parsing
Wide-coverage grammars in Lexicalised Tree-Adjoining Grammar (ltag) and related formalisms are structurally complex, containing many hundreds of elementary trees. In the context of the development of a full-scale ltag-like grammar and parsing system, we have investigated the claim that because many of these trees have a great deal of structure in common, a parser that manipulates trees individually performs a considerable amount of redundant computation. This claim has been used to motivate a parsing technique that encodes trees as nite state automata and captures overlapping computation through automata minimization. Our preliminary results show that this technique leads to considerable computation sharing .
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.
3131824
From RAGS to RICHES: Exploiting the Potential of a Flexible Generation Architecture
The RAGS proposals for generic specification of NLG systems includes a detailed account of data representation, but only an outline view of processing aspects. In this paper we introduce a modular processing architecture with a concrete implementation which aims to meet the RAGS goals of transparency and reusability. We illustrate the model with the RICHES system -- a generation system built from simple linguistically-motivated modules.
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.
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.
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.
2198481
Participatory analysis: shared development of requirements from scenarios
Participatory design typically focuses on envisionment and evaluation activities. We explored a method for pushing the participatory activities further “upstream” in the design process, to the initial analysis of requirements. We used a variant of the task-artifact fi-arnework, carrying out a participatory claims analysis during a design workshop fm a project addressing collaborative science education. The analysis used videotaped classroom sessions as source material. The participant-teachers were highly engaged by the analysis process and contributed significantly to the analysis results. We conclude that the method has promise as a technique for evoking self-reflection and analysis in a participatory design setting.
15595014
Notification and awareness: synchronizing task-oriented collaborative activity
People working collaboratively must establish and maintain awareness of one another's intentions, actions and results. Notification systems typically support awareness of the presence, tasks and actions of collaborators, but they do not adequately support awareness of persistent and complex activities. We analysed awareness breakdowns in use of our Virtual School system--stemming from problems related to the collaborative situation, group, task and tool support--to motivate the concept of activity awareness. Activity awareness builds on prior conceptions of social and action awareness, but emphasizes the importance of activity context factors like planning and coordination. This work suggests design strategies for notification systems to better support collaborative activity.
23810734
Requirements Development in Scenario-Based Design
We describe and analyze the process of requirements development in scenario based design through consideration of a case study. In our project, a group of teachers and system developers initially set out to create a virtual physics laboratory. Our design work centered on the collaborative development of a series of scenarios describing current and future classroom activities. We observed classroom scenarios to assess needs and opportunities, and envisioned future scenarios to specify and analyze possible design moves. We employed claims analysis to evaluate design trade-offs implicit in these scenarios, to codify the specific advantages and disadvantages in achieving requirements. Through the course of this process, the nature of our project requirements has evolved, providing more information but also more kinds of information. We discuss the utility of managing requirements development through an evolving set of scenarios, and the generality of the scenario stages from this case study.
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.
3113915
Learning by doing with simulated intelligent help
Intelligent advisory interfaces will afford new approaches to help and training problems, however little is known about the usability of such facilities. This recent study indicates that although intelligent help can support users, there are also specific potential problems.