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.
16737045
Domain-Specific Sense Distributions and Predominant Sense Acquisition
Distributions of the senses of words are often highly skewed. This fact is exploited by word sense disambiguation (WSD) systems which back off to the predominant sense of a word when contextual clues are not strong enough. The domain of a document has a strong influence on the sense distribution of words, but it is not feasible to produce large manually annotated corpora for every domain of interest. In this paper we describe the construction of three sense annotated corpora in different domains for a sample of English words. We apply an existing method for acquiring predominant sense information automatically from raw text, and for our sample demonstrate that (1) acquiring such information automatically from a mixed-domain corpus is more accurate than deriving it from SemCor, and (2) acquiring it automatically from text in the same domain as the target domain performs best by a large margin. We also show that for an all words WSD task this automatic method is best focussed on words that are salient to the domain, and on words with a different acquired predominant sense in that domain compared to that acquired from a balanced corpus.
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.
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.
14287805
A Formalism and Environment for the Development of a Large Grammar of English
Natural language grammars with large coverage are typically the result of many person-years of effort, working with clumsy formalisms and sub-optimal software support for grammar development. This paper describes our approach to the task of writing a substantial grammar, as part of a collaboration to produce a general purpose morphological and syntactic analyser for English. The grammatical formalism we have developed for the task is a metagrammatical notation which is a more expressive and computationally tractable variant of Generalized Phrase Structure Grammar. We have also implemented a software system which provides a highly integrated and very powerful set of tools for developing and managing a large grammar based on this notation. The system provides a grammarian with an environment which we have found to be essential for rapid but successful production of a substantial grammar.
1566611
Managing evaluation goals for training
goals and are characteristically underresourced. In this article, we describe a framework for managing training evaluation in such contexts. We illustrate by example the feasibility of taking a broad approach toward training evaluation. Scriven [21] introduced the terms formative and summative in his classic work on the objectives and processes of instructional evaluation. Formative evaluation seeks to identify aspects of a design that can be improved. A typical implementation would be having users think aloud as they work through a tutorial to produce a real-time commentary on the nature of the learning experience. Each comment is tightly coupled to a specific design feature, facilitating the identification of problems and reasoning about design solutions. Summative evaluation seeks to gauge a design product. A typical implementation would be measuring time-on-task and error rate to guide decision-making about whether a training system (or the software it supports) should be produced and marketed, or purchased. Formative evaluation work succeeds to the extent that it identifies priorities for redesign and refinement, and all the more to the extent that it provides concrete guidance as to how that redesign and refinement should be executed. Summative evaluation work succeeds to the extent that it allows a design product to be located on various measurement scales with respect to other design products; the stronger the scale (i.e., ratio scale versus interval scale versus ordinal scale versus nominal scale), the better the summative evaluation. Scriven [21] also distinguished two basic types of evaluation method, intrinsic and pay-off :
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.
11544923
Unparsing RDF/XML
It is difficult to serialize an RDF graph as a humanly readable RDF/XML document. This paper describes the approach taken in Jena 1.2, in which a design pattern of guarded procedures invoked using top down recursive descent is used. Each procedure corresponds to a grammar rule; the guard makes the choice about the applicability of the production. This approach is seen to correspond closely to the design of an LL(k) parser, and a theoretical justification of this correspondence is found in universal algebra.
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.
5426813
Machinima: digital performance and emergent authorship
This workshop investigates the emergent online dramatic form of "machinima", the co-option of video game engines or off-the-shelf software for dramatic production in a rapidly developing digital performance form. Workshop participants will engage with short examples of popular machinima productions. There will be discussion and demonstration of the machinima production process. The nexus between dramatic conventions, gameplay and traditional video production techniques will be explored. Participants will work with a short piece of a machinima, in the form of a scene created using the Sims 2 game. Participants will improvise, script and perform dialogue to provide meaning for the action. This workshop applies the insights of process drama, a field well developed in educational settings, to the development of machinima. It includes demonstration and participation in dramatic role, focusing on how the conventions of Role Distance and Role Protection apply to this developing field of digital game-based performance.