Bilingual sentiment lexicon is fundamental resource for cross-language sentiment analysis but its compilation remains a major bottleneck in computational linguistics. Traditional word alignment algorithm faces with the status of large alignment space, which may introduce redundant computations as well as alignment errors. In this paper, we use collocation alignment to extract bilingual sentiment lexicon overcoming the drawbacks of word alignment. The idea of collocation alignment is inspired by the strong cohesion between feature words and opinion words in sentiment corpus. Experimental results show that our approach not only decreases the computing time dramatically but also improves the precision of extracted bilingual word pairs due to the smaller alignment space.

In this paper, we aim to jointly extract aspects and aspect-specific sentiment knowledge from online reviews, where the sentiment knowledge refers to the aspect-specific opinion words along with their aspect-aware sentiment polarities. To this end, we propose a Joint Aspect/Sentiment model (JAS). JAS detects aspect-specific opinion words by integrating opinion word lexicon knowledge to explicitly separate opinion words from factual words. More importantly, JAS exploits sentiment prior and aspect-contextual sentence-level co-occurrences of opinion words in reviews to further identify aspect-aware sentiment polarities for the opinion words. We apply the learned aspect-specific sentiment knowledge to practical aspect-level sentiment analysis tasks. Experimental results show the effectiveness of JAS in learning aspect-specific sentiment knowledge and the practical value of this knowledge when applied to aspect-level sentiment classification.

The explosion of multilingual opinion data has made essential the need for automatic tools to analyze and understand people's opinions in multilingual reviews. In cross-language opinion mining, bilingual opinion lexicon plays a central role. Most of the bilingual lexicon extraction methods are based on EM algorithm. However, these methods are faced with two major problems: high complexity and unsatisfying precision. In this paper, we propose a novel approach to extract bilingual opinion lexicon using collocation alignment, where a collocation is a combination of a feature word and an opinion word. There are tight association between feature words and opinion words, which can be helpful to reduce the computation space and alignment errors. Experimental results demonstrate that our solution is effective and competitive.

This paper aims to find blog feeds having a principal inclination towards making opinionated comments on the given topic, so that we can subscribe to them to track influential and interesting opinions in the blogosphere. One major challenge is assigning topic-related opinion scores to blog feeds, which is embodied in two aspects. Firstly, we should identify whether the blog feed has a principal on-topic opinionated inclination. This inclination should be collectively revealed by all posts of the feed. We should fully consider evidences from all the posts of the feed to identify salient information among many posts of the feed. Secondly, we should capture topic-related opinions in the blog feed while ignoring irrelevant opinions.

Many methods for cross-lingual processing tasks are resource-dependent, which will not work without machine translation system or bilingual lexicon. In this paper, we propose a novel approach for multilingual sentiment classification just by few seed words. For a given language, the proposed approach learns a sentiment classifier from the initial seed words instead of any labeled data. We employ our method both in supervised learning and unsupervised learning. Experimental results demonstrate that our method relies less on external resource but performs as well as or better than the baseline.

Domain-oriented sentiment lexicons are widely used for fine-grained sentiment analysis on reviews; therefore, the automatic construction of domain-oriented sentiment lexicon is a fundamental and important task for sentiment analysis research. Most of existing construction approaches take only the kind of relationships between words into account, which makes them have a lot of room for improvement. This paper proposes an adapted information bottleneck method for the construction of domain-oriented sentiment lexicon. This approach can naturally make full use of the mutual reinforcement between documents and words by fusing three kinds of relationships either from words to documents or from words to words; either homogeneous or heterogeneous; either within-domain or cross-domain. The experimental results demonstrate that proposed method could dramatically improve the accuracy of the baseline approach on the construction of out-of-domain sentiment lexicon.

This paper describes an adapted information bottleneck approach for construction of domain-oriented sentiment lexicon. The basic idea is to use three kinds of relationships (WWinter, WDinter and WDintra,) to infer the semantic orientation of the out-of-domain words. The experimental results demonstrate that proposed method could dramatically improve the accuracy of the baseline approach on the construction of out-of-domain sentiment lexicon.

Sentiment classification is attracting more and more attention because of its great benefits to social and human life. Usually supervised classification approaches perform well in sentiment classification, but the performance decreases sharply when transferred from one domain to another domain. In this paper, we propose an approach, SentiRank, which integrates the sentiment orientations of the documents into the graph-ranking algorithm for cross-domain sentiment classification. We apply the graph-ranking algorithm using the accurate labels of old-domain documents as well as the “pseudo” labels of new-domain documents, and investigate their relative importance for cross-domain sentiment classification. The experiment results indicate that the proposed algorithm could improve the performance of cross-domain sentiment classification dramatically.

In this work, we propose a novel scheme for sentiment classification (without labeled examples) which combines the strengths of both "learn-based" and "lexicon-based" approaches as follows: we first use a lexicon-based technique to label a portion of informative examples from given task (or domain); then learn a new supervised classifier based on these labeled ones; finally apply this classifier to the task. The experimental results indicate that proposed scheme could dramatically outperform "learn-based" and "lexicon-based" techniques.

Splog is the key challenge in the access of blogosphere. Existing splog-filtering methods are restricted to the way for traditional web spam filtering, without considering the characteristics of blogs. Inspired by the observation that fake writers (writers of splogs) have striking higher consistent writing behavior than real writers (writers of legitimate blogs), we propose to detect splogs by distinguishing fake writers from real writers. To measure how consistent the writing behavior is, we propose the consistency-based features derived from writing interval, writing structure and writing topic. Then we designed a splog-filtering system which can use the consistency-based features effectively and flexibly. The experimental results on Blog06 data set show that, proposed measure can effectively detect splogs, reaching an accuracy of 90%. Compared with content-based methods, our approach can get a comparable accuracy with fewer features and smaller train set, indicating that writing consistency represents the essential difference between splogs and blogs.

In this work, we attempt to tackle domain-transfer problem by combining old-domain labeled examples with new-domain unlabeled ones. The basic idea is to use old-domain-trained classifier to label some informative unlabeled examples in new domain, and retrain the base classifier over these selected examples. The experimental results demonstrate that proposed scheme can significantly boost the accuracy of the base sentiment classifier on new domain.

In this work, we explore the use of error-correcting output codes (ECOC) to enhance the performance of centroid text classifier. The framework is to decompose one multi-class problem into multiple binary problems and then learn the individual binary classification problems by centroid classifier. However, this kind of decomposition incurs considerable bias for centroid classifier, which results in noticeable degradation of performance. To address this issue, we use Model-Refinement to adjust this so-called bias.

With the aim to reduce the dimensionality without sacrificing classification performance, the author gains insights from attribute reduction based on discernibility matrix in rough-set theory and proposes two text feature selection algorithms, i.e., DB1 and DB2. The experimental results indicate that DB2 not only yields much higher accuracy than information gain when the number of features is smaller than 6000, but also incurs much smaller CPU time than information gain.

In this paper we present a novel strategy, DragPushing, for improving the performance of text classifiers. The strategy is generic and takes advantage of training errors to successively refine the classification model of a base classifier. We describe how it is applied to generate two new classification algorithms; a Refined Centroid Classifier and a Refined Naïve Bayes Classifier. We present an extensive experimental evaluation of both algorithms on three English collections and one Chinese corpus. The results indicate that in each case, the refined classifiers achieve significant performance improvement over the base classifiers used. Furthermore, the performance of the Refined Centroid Classifier implemented is comparable, if not better, to that of state-of-the-art support vector machine (SVM)-based classifier, but offers a much lower computational cost.

We present a novel algorithm, DragPushing, for automatic text classification. Using a training data set, the algorithm first calculates the prototype vectors, or centroids, for each of the available document classes. Using misclassified examples, it then iteratively refines these centroids; by dragging the centroid of a correct class towards a misclassified example and in the same time pushing the centroid of an incorrect class away from the misclassified example. The algorithm is simple to implement and is computationally very efficient. Evaluation experiments conducted on two benchmark collections show that its classification accuracy is comparable to that of more complex methods, such as support vector machines (SVM).