5260380
A Bag of Useful Techniques for Efficient and Robust Parsing
This paper describes new and improved techniques which help a unification-based parser to process input efficiently and robustly. In combination these methods result in a speed-up in parsing time of more than an order of magnitude. The methods are correct in the sense that none of them rule out legal rule applications.
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.
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.
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.
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.
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.
44645486
Binding objects to scenarios of use
Abstract Scenarios are a natural and effective medium for thinking in general and for design in particular. Our work seeks to develop a potential unification between recent scenario-oriented work in object-oriented analysis/design methods and scenario-oriented work in the analysis/design of human-computer interaction. We illustrate this perspective by showing: (1) how scenario questioning can be used to systematically interrogate the knowledge and practices of potential users, and thereby to create object-oriented analysis models that are psychologically valid; (2) how depicting an individual object's point-of-view can serve as a pedagogical scaffold to help students of object-oriented analysis see how to identify and assign object responsibilities in creating a problem domain model; and (3) how usage scenarios can be employed to motivate and coordinate the design implementation, refactoring and reuse of object-oriented software.
1970300
Acting out the future: a process for envisionment
It is difficult to design innovative information and communication technologies to meet needs that will emerge from future interactions between users, technologies and their situations of use. We have been using scenarios that are acted out as a way of envisioning the future. This paper describes some of the core dilemmas of innovative design. It draws on our existing work as well as ideas from a range of disciplines to present a ‘light’ but useful envisionment process that may be applied to commercial design problems.
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.
8531327
Towards automatic shaping in robot navigation
Shaping is a potentially powerful tool in reinforcement learning applications. Shaping often fails to function effectively because of a lack of understanding about its effects when applied in reinforcement learning settings and the use of inadequate algorithms in its implementation. Due to these difficulties current shaping techniques require some form of manual intervention. We examine some of the principles involved in shaping and present a new algorithm for automatic transferral of knowledge, which uses the Q-values established in a previous task to guide exploration in the learning of a new task. This algorithm is applied to two different but related robot navigation tasks.
7151657
Making use: a design representation