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60
Relational Learning via Collective Matrix Factorization
, 2008
"... Relational learning is concerned with predicting unknown values of a relation, given a database of entities and observed relations among entities. An example of relational learning is movie rating prediction, where entities could include users, movies, genres, and actors. Relations would then encode ..."
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Cited by 130 (4 self)
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Relational learning is concerned with predicting unknown values of a relation, given a database of entities and observed relations among entities. An example of relational learning is movie rating prediction, where entities could include users, movies, genres, and actors. Relations would then encode users ’ ratings of movies, movies ’ genres, and actors ’ roles in movies. A common prediction technique given one pairwise relation, for example a #users × #movies ratings matrix, is lowrank matrix factorization. In domains with multiple relations, represented as multiple matrices, we may improve predictive accuracy by exploiting information from one relation while predicting another. To this end, we propose a collective matrix factorization model: we simultaneously factor several matrices, sharing parameters among factors when an entity participates in multiple relations. Each relation can have a different value type and error distribution; so, we allow nonlinear relationships between the parameters and outputs, using Bregman divergences to measure error. We extend standard alternating projection algorithms to our model, and derive an efficient Newton update for the projection. Furthermore, we propose stochastic optimization methods to deal with large, sparse matrices. Our model generalizes several existing matrix factorization methods, and therefore yields new largescale optimization algorithms for these problems. Our model can handle any pairwise relational schema and a
Topic modeling with network regularization
 In Proc. of the 17th WWW Conference
, 2008
"... In this paper, we formally define the problem of topic modeling with network structure (TMN). We propose a novel solution to this problem, which regularizes a statistical topic model with a harmonic regularizer based on a graph structure in the data. The proposed method combines topic modeling and s ..."
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Cited by 102 (9 self)
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In this paper, we formally define the problem of topic modeling with network structure (TMN). We propose a novel solution to this problem, which regularizes a statistical topic model with a harmonic regularizer based on a graph structure in the data. The proposed method combines topic modeling and social network analysis, and leverages the power of both statistical topic models and discrete regularization. The output of this model can summarize well topics in text, map a topic onto the network, and discover topical communities. With appropriate instantiations of the topic model and the graphbased regularizer, our model can be applied to a wide range of text mining problems such as authortopic analysis, community discovery, and spatial text mining. Empirical experiments on two data sets with different genres show that our approach is effective and outperforms both textoriented methods and networkoriented methods alone. The proposed model is general; it can be applied to any text collections with a mixture of topics and an associated network structure.
Rankingbased clustering of heterogeneous information networks with star network schema
 In: Proc. 2009 ACM SIGKDD Int. Conf. on Knowledge Discovery and Data Mining (KDD 2009
, 2009
"... A heterogeneous information network is an information network composed of multiple types of objects. Clustering on such a network may lead to better understanding of both hidden structures of the network and the individual role played by every object in each cluster. However, although clustering on ..."
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Cited by 85 (30 self)
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A heterogeneous information network is an information network composed of multiple types of objects. Clustering on such a network may lead to better understanding of both hidden structures of the network and the individual role played by every object in each cluster. However, although clustering on homogeneous networks has been studied over decades, clustering on heterogeneous networks has not been addressed until recently. A recent study proposed a new algorithm, RankClus, for clustering on bityped heterogeneous networks. However, a realworld network may consist of more than two types, and the interactions among multityped objects play a key role at disclosing the rich semantics that a network carries. In this paper, we study clustering of multityped heterogeneous networks with a star network schema and propose a novel algorithm, NetClus, that utilizes links across multityped objects to generate highquality netclusters. An iterative enhancement method is developed that leads to effective rankingbased clustering in such heterogeneous networks. Our experiments on DBLP data show that NetClus generates more accurate clustering results than the baseline topic model algorithm PLSA and the recently proposed algorithm, RankClus. Further, NetClus generates informative clusters, presenting good ranking and cluster membership information for each attribute object in each netcluster.
Like like alike — Joint Friendship and Interest Propagation in Social Networks
, 2011
"... Targeting interest to match a user with services (e.g. news, products, games, advertisements) and predicting friendship to build connections among users are two fundamental tasks for social network systems. In this paper, we show that the information contained in interest networks (i.e. userservice ..."
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Cited by 67 (5 self)
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Targeting interest to match a user with services (e.g. news, products, games, advertisements) and predicting friendship to build connections among users are two fundamental tasks for social network systems. In this paper, we show that the information contained in interest networks (i.e. userservice interactions) and friendship networks (i.e. useruser connections) is highly correlated and mutually helpful. We propose a framework that exploits homophily to establish an integrated network linking a user to interested services and connecting different users with common interests, upon which both friendship and interests could be efficiently propagated. The proposed friendshipinterest propagation (FIP) framework devises a factorbased random walk model to explain friendship connections, and simultaneously it uses a coupled latent factor model to uncover interest interactions. We discuss the flexibility of the framework in the choices of loss objectives and regularization penalties and benchmark different variants on the Yahoo! Pulse social networking system. Experiments demonstrate that by coupling friendship with interest, FIP achieves much higher performance on both interest targeting and friendship prediction than systems using only one source of information.
Community Evolution in Dynamic MultiMode Networks
 KDD'08
, 2008
"... A multimode network typically consists of multiple heterogeneous social actors among which various types of interactions could occur. Identifying communities in a multimode network can help understand the structural properties of the network, address the data shortage and unbalanced problems, and ..."
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Cited by 64 (14 self)
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A multimode network typically consists of multiple heterogeneous social actors among which various types of interactions could occur. Identifying communities in a multimode network can help understand the structural properties of the network, address the data shortage and unbalanced problems, and assist tasks like targeted marketing and finding influential actors within or between groups. In general, a network and the membership of groups often evolve gradually. In a dynamic multimode network, both actor membership and interactions can evolve, which poses a challenging problem of identifying community evolution. In this work, we try to address this issue by employing the temporal information to analyze a multimode network. A spectral framework and its scalability issue are carefully studied. Experiments on both synthetic data and realworld large scale networks demonstrate the efficacy of our algorithm and suggest its generality in solving problems with complex relationships.
A Unified View of Matrix Factorization Models
"... Abstract. We present a unified view of matrix factorization that frames the differences among popular methods, such as NMF, Weighted SVD, EPCA, MMMF, pLSI, pLSIpHITS, Bregman coclustering, and many others, in terms of a small number of modeling choices. Many of these approaches can be viewed as m ..."
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Cited by 58 (0 self)
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Abstract. We present a unified view of matrix factorization that frames the differences among popular methods, such as NMF, Weighted SVD, EPCA, MMMF, pLSI, pLSIpHITS, Bregman coclustering, and many others, in terms of a small number of modeling choices. Many of these approaches can be viewed as minimizing a generalized Bregman divergence, and we show that (i) a straightforward alternating projection algorithm can be applied to almost any model in our unified view; (ii) the Hessian for each projection has special structure that makes a Newton projection feasible, even when there are equality constraints on the factors, which allows for matrix coclustering; and (iii) alternating projections can be generalized to simultaneously factor a set of matrices that share dimensions. These observations immediately yield new optimization algorithms for the above factorization methods, and suggest novel generalizations of these methods such as incorporating row and column biases, and adding or relaxing clustering constraints. 1
Statistical predicate invention
 In Z. Ghahramani (Ed.), Proceedings of the 24’th annual international conference on machine learning (ICML2007
, 2007
"... We propose statistical predicate invention as a key problem for statistical relational learning. SPI is the problem of discovering new concepts, properties and relations in structured data, and generalizes hidden variable discovery in statistical models and predicate invention in ILP. We propose an ..."
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Cited by 48 (11 self)
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We propose statistical predicate invention as a key problem for statistical relational learning. SPI is the problem of discovering new concepts, properties and relations in structured data, and generalizes hidden variable discovery in statistical models and predicate invention in ILP. We propose an initial model for SPI based on secondorder Markov logic, in which predicates as well as arguments can be variables, and the domain of discourse is not fully known in advance. Our approach iteratively refines clusters of symbols based on the clusters of symbols they appear in atoms with (e.g., it clusters relations by the clusters of the objects they relate). Since different clusterings are better for predicting different subsets of the atoms, we allow multiple crosscutting clusterings. We show that this approach outperforms Markov logic structure learning and the recently introduced infinite relational model on a number of relational datasets. 1.
Unsupervised Learning on Kpartite Graphs
, 2006
"... Various data mining applications involve data objects of multiple types that are related to each other, which can be naturally formulated as a kpartite graph. However, the research on mining the hidden structures from a kpartite graph is still limited and preliminary. In this paper, we propose a g ..."
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Cited by 46 (4 self)
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Various data mining applications involve data objects of multiple types that are related to each other, which can be naturally formulated as a kpartite graph. However, the research on mining the hidden structures from a kpartite graph is still limited and preliminary. In this paper, we propose a general model, the relation summary network, to find the hidden structures (the local cluster structures and the global community structures) from a kpartite graph. The model provides a principal framework for unsupervised learning on kpartite graphs of various structures. Under this model, we derive a novel algorithm to identify the hidden structures of a kpartite graph by constructing a relation summary network to approximate the original kpartite graph under a broad range of distortion measures. Experiments on both synthetic and real data sets demonstrate the promise and effectiveness of the proposed model and algorithm. We also establish the connections between existing clustering approaches and the proposed model to provide a unified view to the clustering approaches.
Multiway clustering on relation graphs
 In Proc. of the 7th SIAM Intl. Conf. on Data Mining
, 2006
"... A number of realworld domains such as social networks and ecommerce involve heterogeneous data that describes relations between multiple classes of entities. Understanding the natural structure of this type of heterogeneous relational data is essential both for exploratory analysis and for perform ..."
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Cited by 36 (3 self)
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A number of realworld domains such as social networks and ecommerce involve heterogeneous data that describes relations between multiple classes of entities. Understanding the natural structure of this type of heterogeneous relational data is essential both for exploratory analysis and for performing various predictive modeling tasks. In this paper, we propose a principled multiway clustering framework for relational data, wherein different types of entities are simultaneously clustered based not only on their intrinsic attribute values, but also on the multiple relations between the entities. To achieve this, we introduce a relation graph model that describes all the known relations between the different entity classes, in which each relation between a given set of entity classes is represented in the form of multimodal tensor over an appropriate domain. Our multiway clustering formulation is driven by the objective of capturing the maximal “information ” in the original relation graph, i.e., accurately approximating the set of tensors corresponding to the various relations. This formulation is applicable to all Bregman divergences (a broad family of loss functions that includes squared Euclidean distance, KLdivergence), and also permits analysis of mixed data types using convex combinations of appropriate Bregman loss functions. Furthermore, we present a large family of structurally different multiway clustering schemes that preserve various linear summary statistics of the original data. We accomplish the above generalizations by extending a recently proposed key theoretical result, namely the minimum Bregman information principle [1], to the relation graph setting. We also describe an efficient multiway clustering algorithm based on alternate minimization that generalizes a number of other recently proposed clustering methods. Empirical results on datasets obtained from realworld domains (e.g., movie recommendations, newsgroup articles) demonstrate the generality and efficacy of our framework. 1
RankingBased Classification of Heterogeneous Information Networks
"... It has been recently recognized that heterogeneous information networks composed of multiple types of nodes and links are prevalent in the real world. Both classification and ranking of the nodes (or data objects) in such networks are essential for network analysis. However, so far these approaches ..."
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Cited by 32 (11 self)
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It has been recently recognized that heterogeneous information networks composed of multiple types of nodes and links are prevalent in the real world. Both classification and ranking of the nodes (or data objects) in such networks are essential for network analysis. However, so far these approaches have generally been performed separately. In this paper, we combine ranking and classification in order to perform more accurate analysis of a heterogeneous information network. Our intuition is that highly ranked objects within a class should play more important roles in classification. On the other hand, class membership information is important for determining a quality ranking over a dataset. We believe it is therefore beneficial to integrate classification and ranking in a simultaneous, mutually enhancing process, and to this end, propose a novel rankingbased iterative classification framework, called RankClass. Specifically, we build a graphbased ranking model to iteratively compute the ranking distribution of the objects within each class. At each iteration, according to the current ranking results, the graph structure used in the ranking algorithm is adjusted so that the subnetwork corresponding to the specific class is emphasized, while the rest of the network is weakened. As our experiments show, integrating ranking with classification not only generates more accurate classes than the stateofart classification methods on networked data, but also provides meaningful ranking of objects within each class, serving as a more informative view of the data than traditional classification.