16528770
Text Categorization for Improved Priors of Word Meaning
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 (most frequent) sense of a word when contextual clues are not strong enough. The topic domain of a document has a strong influence on the sense distribution of words. Unfortunately, it is not feasible to produce large manually sense-annotated corpora for every domain of interest. Previous experiments have shown that unsupervised estimation of the predominant sense of certain words using corpora whose domain has been determined by hand outperforms estimates based on domain-independent text for a subset of words and even outperforms the estimates based on counting occurrences in an annotated corpus. 
 
In this paper we address the question of whether we can automatically produce domain-specific corpora which could be used to acquire predominant senses appropriate for specific domains. We collect the corpora by automatically classifying documents from a very large corpus of newswire text. Using these corpora we estimate the predominant sense of words for each domain. We first compare with the results presented in [1]. Encouraged by the results we start exploring using text categorization for WSD by evaluating on a standard data set (documents from the SENSEVAL-2 and 3 English all-word tasks). We show that for these documents and using domain-specific predominant senses, we are able to improve on the results that we obtained with predominant senses estimated using general, non domain-specific text. We also show that the confidence of the text classifier is a good indication whether it is worthwhile using the domain-specific predominant sense or not.
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.
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.
11155402
The effect of failure and repair distributions on consistency protocols for replicated data objects
The accessibility of vital information can be enhanced by replicating the data on several sites, and employing a consistency control protocol to manage the copies.
Various protocols have been proposed to ensure that only current copies of the data can be accessed. The effect these protocols have on the accessibility of the replicated data is investigated by simulating the operation of the network and measuring the performance. Several strategies for replica maintenance are considered, and the benefits of each are analyzed. The details of the simulations are discussed. Measurements of the reliability and the availability of the replicated data are compared and contrasted.
The sensitivity of the Available Copy and Dynamic-linear Voting protocols to common patterns of site failures and repairs is studied in detail. Exponential, Erlang, uniform, and hyperexponential distributions are considered, and the effect the second moments have on the results is analyzed. The relative performance of competing protocols is shown to be only marginally affected by non-exponential distributions, validating the robustness of the exponential approximations.
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.
1921535
Interface design issues for advice-giving expert systems
Advice giving could become the first successful domain for intelligent interfaces.
10894513
Block-Level Consistency of Replicated Files
11499441
Matching RDF Graphs
The Resource Description Framework (RDF) describes graphs of statements about resources. RDF is a fundamental lower layer of the semantic web. This paper explores the equality of two RDF graphs in light of the graph isomorphism literature. We consider anonymous resources as unlabelled vertices in a graph, and show that the standard graph isomorphism algorithms, developed in the 1970's, can be used effectively for comparing RDF graphs. The techniques presented are useful for testing RDF software.