A traditional classification approach based on keyword matching represents each text document as a set of keywords, without considering the semantic information, thereby, reducing the accuracy of classification. To so...
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A traditional classification approach based on keyword matching represents each text document as a set of keywords, without considering the semantic information, thereby, reducing the accuracy of classification. To solve this problem, a new classification approach based on Wikipedia matching was proposed, which represents each document as a concept vector in the Wikipedia semantic space so as to understand the text semantics, and has been demonstrated to improve the accuracy of classification. However, the immense Wildpedia semantic space greatly reduces the generation efficiency of a concept vector, resulting in a negative impact on the availability of the approach in an online environment. In this paper, we propose an efficient Wikipedia semantic matching approach to document classification. First, we define several heuristic selection rules to quickly pick out related concepts for a document from the Wikipedia semantic space, making it no longer necessary to match all the concepts in the semantic space, thus greatly improving the generation efficiency of the concept vector. Second, based on the semantic representation of each text document, we compute the similarity between documents so as to accurately classify the documents. Finally, evaluation experiments demonstrate the effectiveness of our approach, i.e., which can improve the classification efficiency of the Wikipedia matching under the precondition of not compromising the classification accuracy. (C) 2017 Elsevier Inc. All rights reserved.
document classification requires to extract high-level features from low-level word vectors. Typically, feature extraction by deep neural networks makes use of all words in a document, which cannot scale well for a lo...
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document classification requires to extract high-level features from low-level word vectors. Typically, feature extraction by deep neural networks makes use of all words in a document, which cannot scale well for a long document. In this paper, we propose to tackle the long document classification task by incorporating the recurrent attention learning framework, which can produce the discriminative features with significantly less words. Specifically, the core work is to train a recurrent neural network (RNN)-based controller, which can focus its attention on the discriminative parts. Then, the glimpsed feature is extracted by a typical short text level convolutional neural network (CNN) from the focused group of words. The controller locates its attention according to the context information, which consists of the coarse representation of the original document and the memorized glimpsed features. By glimpsing a few groups, the document can be classified by aggregating these glimpsed features and the coarse representation. For our collected 11-class 10 000-word arXiv paper data set, the proposed method outperforms two subsampled deep CNN baseline models by a large margin given much less observed words.
document classification is a challenging task to the data being high-dimensional and sparse. Many transfer learning methods have been investigated for improving the classification performance by effectively transferri...
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document classification is a challenging task to the data being high-dimensional and sparse. Many transfer learning methods have been investigated for improving the classification performance by effectively transferring knowledge from a source domain to a target domain, which is similar to but different from the source domain. However, most of the existing methods cannot handle the case that the training data of the target domain does not have labels. In this study, we propose a transductive transfer learning system, utilizing solutions evolved by genetic programming (GP) on a source domain to automatically pseudolabel the training data in the target domain in order to train classifiers. Different from many other transfer learning techniques, the proposed system pseudolabels target-domain training data to retrains classifiers using all target-domain features. The proposed method is examined on nine transfer learning tasks, and the results show that the proposed transductive GP system has better prediction accuracy on the test data in the target domain than existing transfer learning approaches including subspace alignment-domain adaptation methods, feature-level-domain adaptation methods, and one latest pseudolabeling strategy-based method.
Recently, some statistic topic modeling approaches, e.g., Latent Dirichlet allocation (LDA), have been widely applied in the field of document classification. However, standard LDA is a completely unsupervised algorit...
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Recently, some statistic topic modeling approaches, e.g., Latent Dirichlet allocation (LDA), have been widely applied in the field of document classification. However, standard LDA is a completely unsupervised algorithm, and then there is growing interest in incorporating prior information into the topic modeling procedure. Some effective approaches have been developed to model different kinds of prior information, for example, observed labels, hidden labels, the correlation among labels, label frequencies;however, these methods often need heavy computing because of model complexity. In this paper, we propose a new supervised topic model for document classification problems, Twin Labeled LDA (TL-LDA), which has two sets of parallel topic modeling processes, one incorporates the prior label information by hierarchical Dirichlet distributions, the other models the grouping tags, which have prior knowledge about the label correlation;the two processes are independent from each other, so the TL-LDA can be trained efficiently by multi-thread parallel computing. Quantitative experimental results compared with state-of-the-art approaches demonstrate our model gets the best scores on both rank-based and binary prediction metrics in solving single-label classification, and gets the best scores on three metrics, i.e., One Error, Micro-F1, and Macro-F1 while multi-label classification, including non power-law and power-law datasets. The results show benefit from modeling fully prior knowledge, our model has outstanding performance and generalizability on document classification. Further comparisons with recent works also indicate the proposed model is competitive with state-of-the-art approaches.
Topic modeling is an unsupervised learning task that discovers the hidden topics in a collection of documents. In turn, the discovered topics can be used for summarizing, organizing, and understanding the documents in...
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Topic modeling is an unsupervised learning task that discovers the hidden topics in a collection of documents. In turn, the discovered topics can be used for summarizing, organizing, and understanding the documents in the collection. Most of the existing techniques for topic modeling are derivatives of the Latent Dirichlet Allocation which uses a bag-of-word assumption for the documents. However, bag-of-words models completely dismiss the relationships between the words. For this reason, this article presents a two-stage algorithm for topic modelling that leverages word embeddings and word co-occurrence. In the first stage, we determine the topic-word distributions by soft-clustering a random set of embedded n-grams from the documents. In the second stage, we determine the document-topic distributions by sampling the topics of each document from the topic-word distributions. This approach leverages the distributional properties of word embeddings instead of using the bag-of-words assumption. Experimental results on various data sets from an Australian compensation organization show the remarkable comparative effectiveness of the proposed algorithm in a task of document classification.
This work focuses on multiple instance learning (MIL) with sparse positive bags (which we name as sparse MIL). A structural representation is presented to encode both instances and bags. This representation leads to a...
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This work focuses on multiple instance learning (MIL) with sparse positive bags (which we name as sparse MIL). A structural representation is presented to encode both instances and bags. This representation leads to a non-i.i.d. MIL algorithm, miStruct, which uses a structural similarity to compare bags. Furthermore, MIL with this representation is shown to be equivalent to a document classification problem. document classification also suffers from the fact that only few paragraphs/words are useful in revealing the category of a document. By using the TF-IDF representation which has excellent empirical performance in document classification, the miDoc method is proposed. The proposed methods achieve significantly higher accuracies and AUC (area under the ROC curve) than the state-of-the-art in a large number of sparse MIL problems, and the document classification analogy explains their efficacy in sparse MIL problems.
Many companies are facing growing data archives leading to an increasing focus on the automated classification of documents in corporate processes. Due to data protection guidelines, development with clear data is oft...
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Many companies are facing growing data archives leading to an increasing focus on the automated classification of documents in corporate processes. Due to data protection guidelines, development with clear data is often difficult. One way to overcome this difficulty is to desensitize documents using document redaction. The following study, therefore, examines the impact of redaction on the document classification performance of a deep CNN model by analyzing how the classification performance deteriorates when the model is trained on unredacted documents and evaluated on redacted data (unredacted model) or trained on redacted data and applied to unredacted documents (redacted model). For the former condition, a loss in accuracy of 2.56%P was found and a loss of 2.08%P for the latter. We were also able to show that the loss in performance differed greatly between document classes and was influenced by their proportion of redacted area (unredacted model: r=0.31;redacted model: r=0.87). For the model trained with redacted and evaluated on unredacted data, we also determined that the decrease in classification accuracy was affected by the intra-class variability of the redacted area (r=0.74). From these results, recommendations for dealing with redacted data in document classification systems are derived.
In this paper, a novel discriminative learning method is proposed to estimate generative models for multi-class pattern classification tasks, where a discriminative objective function is formulated with separation mar...
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In this paper, a novel discriminative learning method is proposed to estimate generative models for multi-class pattern classification tasks, where a discriminative objective function is formulated with separation margins according to certain discriminative learning criterion, such as large margin estimation (LME). Furthermore, the so-called approximation-maximization (AM) method is proposed to optimize the discriminative objective function w.r.t. parameters of generative models. The AM approach provides a good framework to deal with latent variables in generative models and it is flexible enough to discriminatively learn many rather complicated generative models. In this paper, we are interested in a group of generative models derived from multinomial distributions. Under some minor relaxation conditions, it is shown that the AM-based discriminative learning methods for these generative models result in linear programming (LP) problems that can be solved effectively and efficiently even for rather large-scale models. As a case study, we have studied to learn multinomial mixture models (MMMs) for text document classification based on the large margin criterion. The proposed methods have been evaluated on a standard RCV1 text corpus. Experimental results show that large margin MMMs significantly outperform the conventional MMMs as well as pure discriminative models such as support vector machines (SVM), where over 25 % relative classification error reduction is observed in three independent RCV1 test sets.
We propose a class-based mixture of topic models for classifying documents using both labeled and unlabeled examples (i.e., in a semi-supervised fashion). Most topic models incorporate documents' class labels by g...
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We propose a class-based mixture of topic models for classifying documents using both labeled and unlabeled examples (i.e., in a semi-supervised fashion). Most topic models incorporate documents' class labels by generating them after generating the words. In these models, the training class labels have small effect on the estimated topics, as they are effectively treated as just another word, amongst a huge set of word features. In this paper, we propose to increase the influence of class labels on topic models by generating the words in each document conditioned on the class label. We show that our specific generative process improves classification performance with small loss in test set log-likelihood. Within our framework, we provide a principled mechanism to control the contributions of the class labels and the word space to the likelihood function. Experiments show our approach achieves better classification accuracy compared to some standard semi-supervised and supervised topic models.
We present a simple and yet effective approach for document classification to incorporate rationales elicited from annotators into the training of any off-the-shelf classifier. We empirically show on several document ...
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We present a simple and yet effective approach for document classification to incorporate rationales elicited from annotators into the training of any off-the-shelf classifier. We empirically show on several document classification datasets that our classifier-agnostic approach, which makes no assumptions about the underlying classifier, can effectively incorporate rationales into the training of multinomial na < ve Bayes, logistic regression, and support vector machines. In addition to being classifier-agnostic, we show that our method has comparable performance to previous classifier-specific approaches developed for incorporating rationales and feature annotations. Additionally, we propose and evaluate an active learning method tailored specifically for the learning with rationales framework.
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