This paper focuses on semantic role labeling using automatically-generated syntactic information. A simple and robust strategy for system combination is presented, which allows to partially recover from input parsing errors and to significantly boost results of individual systems. This combination scheme is also very flexible since the individual systems are not required to provide any information other than their solution. Extensive experimental evaluation in the CoNLL-2005 shared task framework supports our previous claims. The proposed architecture outperforms the best results reported in that evaluation exercise.

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This paper contributes a formalization of frame-semantic parsing as a structure prediction problem and describes an implemented parser that transforms an English sentence into a frame-semantic representation. It finds words that evoke FrameNet frames, selects frames for them, and locates the arguments for each frame. The system uses two featurebased, discriminative probabilistic (log-linear) models, one with latent variables to permit disambiguation of new predicate words. The parser is demonstrated to significantly outperform previously published results. 1

This paper considers the problem of unsupervised semantic lexicon acquisition. We introduce a fully automatic approach which exploits parallel corpora, relies on shallow text properties, and is relatively inexpensive. Given the English FrameNet lexicon, our method exploits word alignments to generate frame candidate lists for new languages, which are subsequently pruned automatically using a small set of linguistically motivated filters. Evaluation shows that our approach can produce high-precision multilingual FrameNet lexicons without recourse to bilingual dictionaries or deep syntactic and semantic analysis.

We propose a robust method of automatically constructing a bilingual word sense dictionary from readily available monolingual ontologies by using estimation-maximization, without any annotated training data or manual tuning. We demonstrate our method on the English FrameNet and Chinese HowNet structures. Owing to the robustness of EM iterations in improving translation likelihoods, our word sense translation accuracies are very high, at 82 % on average, for the 11 most ambiguous words in the English FrameNet with 5 senses or more. We also carried out a pilot study on using this automatically generated bilingual word sense dictionary to choose the best translation candidates and show the first significant evidence that frame semantics are useful for translation disambiguation. Translation disambiguation accuracy using frame semantics is 75%, compared to 15 % by using dictionary glossing only. These results demonstrate the great potential for future application of bilingual frame semantics to machine translation tasks. 1

In recent years, with the development of Chinese semantically annotated corpus, such as Chinese Proposition Bank and Normalization Bank, the Chinese semantic role labeling (SRL) task has been boosted. Similar to English, the Chinese SRL can be divided into two tasks: semantic role identification (SRI) and classification (SRC). Many features were introduced into these tasks and promising results were achieved. In this paper, we mainly focus on the second task: SRC. After exploiting the linguistic discrepancy between numbered arguments and ARGMs, we built a semantic role classifier based on a hierarchical feature selection strategy. Different from the previous SRC systems, we divided SRC into three sub tasks in sequence and trained models for each sub task. Under the hierarchical architecture, each argument should first be determined whether it is a numbered argument or an ARGM, and then be classified into finegained categories. Finally, we integrated the idea of exploiting argument interdependence into our system and further improved the performance. With the novel method, the classification precision of our system is 94.68%, which outperforms the strong baseline significantly. It is also the state-of-the-art on Chinese SRC. 1

This paper describes an approach to analyzing the lexical structure of OCRed bilingual dictionaries to construct resources suited for machine translation of low-density languages, where online resources are limited. A rule-based, an HMM-based, and a post-processed HMM-based method are used for rapid construction of MT lexicons based on systematic structural clues provided in the original dictionary. We evaluate the effectiveness of our techniques, concluding that: (1) the rule-based method performs better with dictionaries where the font is not an important distinguishing feature for determining information types; (2) the post-processed stochastic method improves the results of the stochastic method for phrasal entries; and (3) Our resulting bilingual lexicons are comprehensive enough to provide the basis for reasonable translation results when compared to human translations.

In memory of my grandfather, LAW Yuk Kau, who passed away several months before I started this study. He gave me strength, kept me determined in my research and helped me realize my career goal. He will always live in my heart. iv ACKNOWLEDGMENTS I would like to express my deepest thanks to my supervisor Professor Dekai Wu. Not only has he shared with me his insightful ideas and comments in my research, he has also supported me throughout the whole program of my study. From the time I approached him showing an interest in pursuing a postgraduate degree to now as I graduate, he has always been positive about my ability and work. His encouragement and indulgence has enabled me to complete my study. I would also like to thank Professor Pascale Fung. This thesis work has been developed on top of her research group’s product, C-ASSERT. Her generosity in sharing research ideas has been a key factor in the completion of this thesis. I am also grateful to her and Professor Brian Mak for sparing their valuable time to join my defense committee. Thanks go to Ms. Shuana Dalton and Miss Joanne Ng for helping me to review my thesis.

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Knowledge representation of the Quran through frame semantics A corpus-based approach