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Relation Classification via Convolutional Deep Neural Network
"... The state-of-the-art methods used for relation classification are primarily based on statistical ma-chine learning, and their performance strongly depends on the quality of the extracted features. The extracted features are often derived from the output of pre-existing natural language process-ing ( ..."
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The state-of-the-art methods used for relation classification are primarily based on statistical ma-chine learning, and their performance strongly depends on the quality of the extracted features. The extracted features are often derived from the output of pre-existing natural language process-ing (NLP) systems, which leads to the propagation of the errors in the existing tools and hinders the performance of these systems. In this paper, we exploit a convolutional deep neural network (DNN) to extract lexical and sentence level features. Our method takes all of the word tokens as input without complicated pre-processing. First, the word tokens are transformed to vectors by looking up word embeddings1. Then, lexical level features are extracted according to the given nouns. Meanwhile, sentence level features are learned using a convolutional approach. These two level features are concatenated to form the final extracted feature vector. Finally, the fea-tures are fed into a softmax classifier to predict the relationship between two marked nouns. The experimental results demonstrate that our approach significantly outperforms the state-of-the-art methods. 1
Relation extraction from the web using distant supervision
- In Janowicz et al
"... Abstract. Extracting information from Web pages requires the ability to work at Web scale in terms of the number of documents, the number of domains and domain complexity. Recent approaches have used existing knowledge bases to learn to extract information with promising results. In this paper we pr ..."
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Abstract. Extracting information from Web pages requires the ability to work at Web scale in terms of the number of documents, the number of domains and domain complexity. Recent approaches have used existing knowledge bases to learn to extract information with promising results. In this paper we propose the use of distant supervision for relation extraction from the Web. Distant supervision is a method which uses background information from the Linking Open Data cloud to automatically label sentences with relations to create training data for relation classifiers. Although the method is promising, existing approaches are still not suitable for Web extraction as they suffer from three main issues: data sparsity, noise and lexical ambiguity. Our approach reduces the impact of data sparsity by making entity recognition tools more robust across domains, as well as extracting relations across sentence boundaries. We reduce the noise caused by lexical ambiguity by employing statistical methods to strategically select training data. Our experiments show that using a more robust entity recognition approach and expanding the scope of relation extraction results in about 8 times the number of extractions, and that strategically selecting training data can result in an error reduction of about 30%. 1
Distant supervision for relation extraction with matrix completion
- In Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (ACL
, 2014
"... Abstract The essence of distantly supervised relation extraction is that it is an incomplete multi-label classification problem with sparse and noisy features. To tackle the sparsity and noise challenges, we propose solving the classification problem using matrix completion on factorized matrix of ..."
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Abstract The essence of distantly supervised relation extraction is that it is an incomplete multi-label classification problem with sparse and noisy features. To tackle the sparsity and noise challenges, we propose solving the classification problem using matrix completion on factorized matrix of minimized rank. We formulate relation classification as completing the unknown labels of testing items (entity pairs) in a sparse matrix that concatenates training and testing textual features with training labels. Our algorithmic framework is based on the assumption that the rank of item-byfeature and item-by-label joint matrix is low. We apply two optimization models to recover the underlying low-rank matrix leveraging the sparsity of feature-label matrix. The matrix completion problem is then solved by the fixed point continuation (FPC) algorithm, which can find the global optimum. Experiments on two widely used datasets with different dimensions of textual features demonstrate that our low-rank matrix completion approach significantly outperforms the baseline and the state-of-the-art methods.
Seed Selection for Distantly Supervised Web-Based Relation Extraction
"... In this paper we consider the problem of distant supervision to extract relations (e.g. origin(musical artist, location)) for entities (e.g. ‘The Beatles’) of certain classes (e.g. musical artist) from Web pages by using background information from the Linking Open Data cloud to automatically label ..."
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In this paper we consider the problem of distant supervision to extract relations (e.g. origin(musical artist, location)) for entities (e.g. ‘The Beatles’) of certain classes (e.g. musical artist) from Web pages by using background information from the Linking Open Data cloud to automatically label Web documents which are then used as training data for relation classifiers. Distant supervision approaches typically suffer from the problem of ambiguity when automatically labelling text, as well as the problem of incompleteness of background data to judge whether a mention is a true relation mention. This paper explores the hypothesis that simple statistical methods based on background data can help to filter unreliable training data and thus improve the precision of relation extractors. Experiments on a Web corpus show that an error reduction of 35 % can be achieved by strategically selecting seed data. 1
Joint Information Extraction from the Web using Linked Data
- Proceedings of ISWC (2014) Augenstein et al. / Distantly Supervised Web Relation Extraction for Knowledge Base Population 13
"... Abstract. Almost all of the big name Web companies are currently engaged in building ‘knowledge graphs ’ and these are showing significant results in improving search, email, calendaring, etc. Even the largest openly-accessible ones, such as Freebase and Wikidata, are far from complete, partly becau ..."
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Abstract. Almost all of the big name Web companies are currently engaged in building ‘knowledge graphs ’ and these are showing significant results in improving search, email, calendaring, etc. Even the largest openly-accessible ones, such as Freebase and Wikidata, are far from complete, partly because new information is emerging so quickly. Most of the missing information is available on Web pages. To access that knowledge and populate knowledge bases, information extraction methods are necessitated. The bottleneck for information extraction systems is obtaining training data to learn classifiers. In this doctoral research, we investigate how existing data in knowledge bases can be used to automatically annotate training data to learn classifiers to in turn extract more data to expand knowledge bases. We discuss our hypotheses, approach, evaluation methods and present preliminary results. 1 Problem Statement Since the emergence of the Semantic Web, many Linked datasets such as Freebase [5], Wikidata [31] and DBpedia [4] have been created, not only for research, but also com-
Robust domain adaptation for relation extraction via clustering consistency
- In ACL. Denis Paperno, The Nghia
, 2014
"... Abstract We propose a two-phase framework to adapt existing relation extraction classifiers to extract relations for new target domains. We address two challenges: negative transfer when knowledge in source domains is used without considering the differences in relation distributions; and lack of a ..."
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Abstract We propose a two-phase framework to adapt existing relation extraction classifiers to extract relations for new target domains. We address two challenges: negative transfer when knowledge in source domains is used without considering the differences in relation distributions; and lack of adequate labeled samples for rarer relations in the new domain, due to a small labeled data set and imbalance relation distributions. Our framework leverages on both labeled and unlabeled data in the target domain. First, we determine the relevance of each source domain to the target domain for each relation type, using the consistency between the clustering given by the target domain labels and the clustering given by the predictors trained for the source domain. To overcome the lack of labeled samples for rarer relations, these clusterings operate on both the labeled and unlabeled data in the target domain. Second, we trade-off between using relevance-weighted sourcedomain predictors and the labeled target data. Again, to overcome the imbalance distribution, the source-domain predictors operate on the unlabeled target data. Our method outperforms numerous baselines and a weakly-supervised relation extraction method on ACE 2004 and YAGO.
Medical Relation Extraction with Manifold Models
"... In this paper, we present a manifold model for medical relation extraction. Our model is built upon a medical corpus containing 80M sentences (11 gigabyte text) and de-signed to accurately and efciently detect the key medical relations that can facilitate clinical decision making. Our approach integ ..."
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In this paper, we present a manifold model for medical relation extraction. Our model is built upon a medical corpus containing 80M sentences (11 gigabyte text) and de-signed to accurately and efciently detect the key medical relations that can facilitate clinical decision making. Our approach integrates domain specic parsing and typ-ing systems, and can utilize labeled as well as unlabeled examples. To provide users with more exibility, we also take label weight into consideration. Effectiveness of our model is demonstrated both theo-retically with a proof to show that the so-lution is a closed-form solution and exper-imentally with positive results in experi-ments. 1
Exploring Distinctive Features in Distant Supervision for Relation Extraction
"... Abstract. Distant supervision (DS) for relation extraction suffers from the noisy labeling problem. Most solutions try to model the noisy instances in the form of multi-instance learning. However, in the non-noisy instances, there may be noisy features which would harm the extraction model. In this ..."
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Abstract. Distant supervision (DS) for relation extraction suffers from the noisy labeling problem. Most solutions try to model the noisy instances in the form of multi-instance learning. However, in the non-noisy instances, there may be noisy features which would harm the extraction model. In this paper, we employ a novel approach to address this problem by exploring distinctive features and assigning distinctive features more weight than the noisy ones. We make use of all the training data (both the labeled part that satisfies the DS assumption and the part that does not), and then employ an unsupervised method by topic model to discover the distribution of features to latent relations. At last, we compute the distinctiveness of features by using the obtained feature-relation distribution, and assign features weights based on their distinctiveness to train the extractor. Experiments show that the approach outperforms the baseline methods in both the held-out evaluation and the manual evaluation significantly.
iii Acknowledgements
, 2013
"... First of all, I would like to thank my advisor Prof. Ralph Grishman. Ralph introduced me to the fascinating world of Information Extraction and taught me howtodoresearch. I’mextremelygratefulforhispatience, especiallyforanswering my questions in the late night, helping me with proofreading my draft ..."
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First of all, I would like to thank my advisor Prof. Ralph Grishman. Ralph introduced me to the fascinating world of Information Extraction and taught me howtodoresearch. I’mextremelygratefulforhispatience, especiallyforanswering my questions in the late night, helping me with proofreading my draft papers even got it at the last minute. Ralph is always very supportive through my PhD study. This dissertation won’t be possible without his guidance. Second, I would like to thank my other mentors in the proteus group: Prof. Satoshi Sekine and Prof. Adam Meyers. Satoshi is an insipirasion to several of my research projects. Adam is the linguist that I always asked for help when I had questions. I would also like to thank my other comittee members: Prof. Heng Ji, Prof. Ernest Davis, and Prof. Dennis Shasha. Third, I am indebt to two former proteus group members, Ang Sun and Shasha Liao. Their knowledge and passion on Information Extraction has directly led me to choose the field for my PhD. I’m especially grateful to Ang, who shared with me his code which is an excellent example of language engineering and the entry point to one of my research projects. I would like to thank following current members of
Using Commonsense Knowledge to Automatically Create (Noisy) Training Examples from Text
"... One of the challenges to information extraction is the require-ment of human annotated examples. Current successful ap-proaches alleviate this problem by employing some form of distant supervision i.e., look into knowledge bases such as Freebase as a source of supervision to create more examples. Wh ..."
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One of the challenges to information extraction is the require-ment of human annotated examples. Current successful ap-proaches alleviate this problem by employing some form of distant supervision i.e., look into knowledge bases such as Freebase as a source of supervision to create more examples. While this is perfectly reasonable, most distant supervision methods rely on a hand coded background knowledge that explicitly looks for patterns in text. In this work, we take a different approach – we create weakly supervised examples for relations by using commonsense knowledge. The key in-novation is that this commonsense knowledge is completely independent of the natural language text. This helps when learning the full model for information extraction as against simply learning the parameters of a known CRF or MLN. We demonstrate on two domains that this form of weak supervi-sion yields superior results when learning structure compared to simply using the gold standard labels. 1