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Thesis

The study on automatic Chinese collocation extraction

Authors: Xu, Ruifeng (2006)

Collocation is a lexical phenomenon in which two or more words are habitually combined together as some conventional way of saying things. Collocation information is essential to many natural language processing tasks such as word sense disambiguation, machine translation, and information extraction. Most of current works on collocation extraction are statistical based with limited precision and recall because they can not well distinguish word co-occurrences, which are statistically 'significant, from true collocations, which are of habitual use and are thus either syntactically or semantically significant. The objective of this study is to investigate methods to improve the performance of Chinese collocation extraction algorithms. Different types of collocations are identified. C...

Thesis

The value of shared visual information for task-oriented collaboration

Authors: Gergle, Darren R. (2006)

For several decades, researchers and engineers have struggled with the development of systems to support distance collaboration. The failure of many collaborative technologies is due, in part, to a limited understanding of how groups coordinate in collocated environments and how the coordination mechanisms of face-to-face collaboration are impacted by technology. The major goal of this thesis is to address this deficiency by building a theoretical understanding of the role that shared visual information plays in supporting group communication and performance during task-oriented collaboration. This understanding is developed over three major stages: (1) the development of a paradigm and a series of empirical studies that decompose the features of shared visual information and task s...

Thesis

The weight in a Serre-type conjecture for tame n-dimensional Galois representations

Authors: Herzig, Florian (2006)

We formulate a conjecture generalising the weight in Serre's Conjecture to n-dimensional representations p : Gal(U/Q) -* GLn(IF,) that are tamely ramified at p. A weight in this context is an irreducible representation of GLn(1Fp) over Pp. The conjecture describes the predicted set of weights in terms of the reduction modulo p of a Deligne-Lusztig repre¬sentation of GLn(Fp) which only depends on the restriction of p to the inertia subgroup at p. When n = 3 a weight conjecture had already been made by Ash, Doud, Pollack and Sinnott. The advantage of our conjecture is that it is more conceptual. It moreover predicts more weights for many representations p. We give computational examples which strongly suggest the existence of these extra weights. When n = 4 we obtain some theoretica...

Thesis

Three dimensional strain measurement by a Bragg grating sensor subjected to axial and transverse load simultaneously

Authors: Mawatari, Tadamichi (2006)

The objective of this thesis is to establish mathematical models for predicting strains in the axial and other two orthogonal (transverse) directions of a multi-parameter Bragg grating sensor which is subjected to an axial and transverse loadings simultaneously. Previous work by other researchers has established models for predicting axial strains, but not a combination of those three strain components. Test specimens consisted of polarization maintaining Bragg grating sensors created in optical fibers with bow-tie stress applying parts. Each of the sensors had two Bragg wavelength peaks at around 1300 nm, and two others around 1550 nm, and those four peaks moved due to external stimuli such as applied loads and/or temperature changes. The change in wavelength from a certain refe...

Thesis

Three-dimensional volume averaged soil-moisture transport model: A scalable scheme for representing subgrid topographic control in land-atmosphere interactions

Authors: Choi, Hyun Il (2006)

Climate models, both global and regional, have increased in sophistication and are being run at increasingly higher resolutions. The land surface models (LSMs) coupled to these climate models have also evolved from simple bucket models to the new generation models needed to support sophisticated linkages and process interactions at small scales to assess their cumulative impact at larger scales. This is possible by substantially improving the land-surface parameterization in these models to account for subgrid processes. Although topographic data is one of the most readily available high resolution products with continental and global coverage, heterogeneity induced by topographic characteristics, such as slopes and curvatures, is generally not well represented in the models. These ...

Thesis

Understanding the process of multi-document summarization: Content selection, rewriting and evaluation

Authors: Nenkova, Ani (2006)

Recent years have seen unprecedented interest in news aggregation and browsing, with dedicated corporate and research websites becoming increasingly popular. Generic multi-document summarization can enhance users' experiences with such sites, and thus the development and evaluation of automatic summarization systems has become not only research, but a very practical challange. In this thesis, we describe a general modular automatic summarizer that achieves state of the art performance, present our experiments with rewrite of generic noun phrases and of references to people, and demonstrate how distinctions such as familiarity and salience of entities mentioned in the input can be automatically determined. We also propose an intrinsic evaluation method for summarization that incorpor...