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134
Mixed membership stochastic block models for relational data with application to proteinprotein interactions
 In Proceedings of the International Biometrics Society Annual Meeting
, 2006
"... We develop a model for examining data that consists of pairwise measurements, for example, presence or absence of links between pairs of objects. Examples include protein interactions and gene regulatory networks, collections of authorrecipient email, and social networks. Analyzing such data with p ..."
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Cited by 378 (52 self)
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We develop a model for examining data that consists of pairwise measurements, for example, presence or absence of links between pairs of objects. Examples include protein interactions and gene regulatory networks, collections of authorrecipient email, and social networks. Analyzing such data with probabilistic models requires special assumptions, since the usual independence or exchangeability assumptions no longer hold. We introduce a class of latent variable models for pairwise measurements: mixed membership stochastic blockmodels. Models in this class combine a global model of dense patches of connectivity (blockmodel) and a local model to instantiate nodespecific variability in the connections (mixed membership). We develop a general variational inference algorithm for fast approximate posterior inference. We demonstrate the advantages of mixed membership stochastic blockmodels with applications to social networks and protein interaction networks.
Reading Tea Leaves: How Humans Interpret Topic Models
"... Probabilistic topic models are a popular tool for the unsupervised analysis of text, providing both a predictive model of future text and a latent topic representation of the corpus. Practitioners typically assume that the latent space is semantically meaningful. It is used to check models, summariz ..."
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Cited by 238 (26 self)
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Probabilistic topic models are a popular tool for the unsupervised analysis of text, providing both a predictive model of future text and a latent topic representation of the corpus. Practitioners typically assume that the latent space is semantically meaningful. It is used to check models, summarize the corpus, and guide exploration of its contents. However, whether the latent space is interpretable is in need of quantitative evaluation. In this paper, we present new quantitative methods for measuring semantic meaning in inferred topics. We back these measures with largescale user studies, showing that they capture aspects of the model that are undetected by previous measures of model quality based on heldout likelihood. Surprisingly, topic models which perform better on heldout likelihood may infer less semantically meaningful topics. 1
A CORRELATED TOPIC MODEL OF SCIENCE
, 2007
"... Topic models, such as latent Dirichlet allocation (LDA), can be useful tools for the statistical analysis of document collections and other discrete data. The LDA model assumes that the words of each document arise from a mixture of topics, each of which is a distribution over the vocabulary. A limi ..."
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Cited by 156 (10 self)
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Topic models, such as latent Dirichlet allocation (LDA), can be useful tools for the statistical analysis of document collections and other discrete data. The LDA model assumes that the words of each document arise from a mixture of topics, each of which is a distribution over the vocabulary. A limitation of LDA is the inability to model topic correlation even though, for example, a document about genetics is more likely to also be about disease than Xray astronomy. This limitation stems from the use of the Dirichlet distribution to model the variability among the topic proportions. In this paper we develop the correlated topic model (CTM), where the topic proportions exhibit correlation via the logistic normal distribution [J. Roy. Statist. Soc. Ser. B 44 (1982) 139–177]. We derive a fast variational inference algorithm for approximate posterior inference in this model, which is complicated by the fact that the logistic normal is not conjugate to the multinomial. We apply the CTM to the articles from Science published from 1990–1999, a data set that comprises 57M words. The CTM gives a better fit of the data than LDA, and we demonstrate its use as an exploratory tool of large document collections.
Joint Latent Topic Models for Text and Citations
, 2008
"... In this work, we address the problem of joint modeling of text and citations in the topic modeling framework. We present two different models called the PairwiseLinkLDA and the LinkLDAPLSA models. The PairwiseLinkLDA model combines the ideas of LDA [4] and Mixed Membership Block Stochastic Mod ..."
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Cited by 99 (11 self)
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In this work, we address the problem of joint modeling of text and citations in the topic modeling framework. We present two different models called the PairwiseLinkLDA and the LinkLDAPLSA models. The PairwiseLinkLDA model combines the ideas of LDA [4] and Mixed Membership Block Stochastic Models [1] and allows modeling arbitrary link structure. However, the model is computationally expensive, since it involves modeling the presence or absence of a citation (link) between every pair of documents. The second model solves this problem by assuming that the link structure is a bipartite graph. As the name indicates, LinkPLSALDA model combines the LDA and PLSA models into a single graphical model. Our experiments on a subset of Citeseer data show that both these models are able to predict unseen data better than the baseline model of Erosheva and Lafferty [8], by capturing the notion of topical similarity between the contents of the cited and citing documents. Our experiments on two different data sets on the link prediction task show that the LinkPLSALDA model performs the best on the citation prediction task, while also remaining highly scalable. In addition, we also present some interesting visualizations generated by each of the models.
Centerpiece subgraphs: Problem definition and fast solutions
 In KDD
, 2006
"... Given Q nodes in a social network (say, authorship network), how can we find the node/author that is the centerpiece, and has direct or indirect connections to all, or most of them? For example, this node could be the common advisor, or someone who started the research area that the Q nodes belong t ..."
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Cited by 77 (23 self)
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Given Q nodes in a social network (say, authorship network), how can we find the node/author that is the centerpiece, and has direct or indirect connections to all, or most of them? For example, this node could be the common advisor, or someone who started the research area that the Q nodes belong to. Isomorphic scenarios appear in law enforcement (find the mastermind criminal, connected to all current suspects), gene regulatory networks (find the protein that participates in pathways with all or most of the given Q proteins), viral marketing and many more. Connection subgraphs is an important first step, handling the case of Q=2 query nodes. Then, the connection subgraph algorithm finds the b intermediate nodes, that provide a good connection between the two original query nodes. Here we generalize the challenge in multiple dimensions: First, we allow more than two query nodes. Second, we allow a whole family of queries, ranging from ’OR ’ to ’AND’, with ’softAND ’ inbetween. Finally, we design and compare a fast approximation, and study the quality/speed tradeoff. We also present experiments on the DBLP dataset. The experiments confirm that our proposed method naturally deals with multisource queries and that the resulting subgraphs agree with our intuition. Wallclock timing results on the DBLP dataset show that our proposed approximation achieve good accuracy for about 6: 1 speedup. This material is based upon work supported by the
HIERARCHICAL RELATIONAL MODELS FOR DOCUMENT NETWORKS
, 2010
"... We develop the relational topic model (RTM), a hierarchical model of both network structure and node attributes. We focus on document networks, where the attributes of each document are its words, that is, discrete observations taken from a fixed vocabulary. For each pair of documents, the RTM model ..."
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Cited by 55 (4 self)
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We develop the relational topic model (RTM), a hierarchical model of both network structure and node attributes. We focus on document networks, where the attributes of each document are its words, that is, discrete observations taken from a fixed vocabulary. For each pair of documents, the RTM models their link as a binary random variable that is conditioned on their contents. The model can be used to summarize a network of documents, predict links between them, and predict words within them. We derive efficient inference and estimation algorithms based on variational methods that take advantage of sparsity and scale with the number of links. We evaluate the predictive performance of the RTM for large networks of scientific abstracts, web documents, and geographically tagged news.
Open Domain Event Extraction from Twitter
"... Tweets are the most uptodate and inclusive stream of information and commentary on current events, but they are also fragmented and noisy, motivating the need for systems that can extract, aggregate and categorize important events. Previous work on extracting structured representations of events h ..."
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Cited by 52 (3 self)
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Tweets are the most uptodate and inclusive stream of information and commentary on current events, but they are also fragmented and noisy, motivating the need for systems that can extract, aggregate and categorize important events. Previous work on extracting structured representations of events has focused largely on newswire text; Twitter’s unique characteristics present new challenges and opportunities for opendomain event extraction. This paper describes TwiCal— the first opendomain eventextraction and categorization system for Twitter. We demonstrate that accurately extracting an opendomain calendar of significant events from Twitter is indeed feasible. In addition, we present a novel approach for discovering important event categories and classifying extracted events based on latent variable models. By leveraging large volumes of unlabeled data, our approach achieves a 14 % increase in maximum F1 over a supervised baseline. A continuously updating demonstration of our system can be viewed at
Linkplsalda: A new unsupervised model for topics and influence in blogs
 In ICWSM
, 2008
"... In this work, we address the twin problems of unsupervised topic discovery and estimation of topic specific influence of blogs. We propose a new model that can be used to provide a user with highly influential blog postings on the topic of the user’s interest. We adopt the framework of an unsupervis ..."
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Cited by 45 (2 self)
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In this work, we address the twin problems of unsupervised topic discovery and estimation of topic specific influence of blogs. We propose a new model that can be used to provide a user with highly influential blog postings on the topic of the user’s interest. We adopt the framework of an unsupervised model called Latent Dirichlet Allocation(Blei, Ng, & Jordan 2003), known for its effectiveness in topic discovery. An extension of this model, which we call LinkLDA (Erosheva, Fienberg, & Lafferty 2004), defines a generative model for hyperlinks and thereby models topic specific influence of documents, the problem of our interest. However, this model does not exploit the topical relationship between the documents on either side of a hyperlink, i.e., the notion that documents tend to link to other documents on the same topic. We propose a new model, called LinkPLSALDA, that combines PLSA (Hoffman 1999) and LDA (Blei, Ng, & Jordan 2003) into a single framework, and explicitly models the topical relationship between the linking and the linked document. The output of the new model on blog data reveals very interesting visualizations of topics and influential blogs on each topic. We also perform quantitative evaluation of the model using loglikelihood of unseen data and on the task of link prediction. Both experiments show that that the new model performs better, suggesting its superiority over LinkLDA in modeling topics and topic specific influence of blogs.