## Abstract / Description of output

Graph pattern matching has been widely used in e.g., social data analysis. A number of matching algorithms have been developed that, given a graph pattern Q and a graph G, compute the set M(Q;G) of matches of Q in G. However, these algorithms often return an excessive number of matches, and are expensive on large real-life social graphs. Moreover, in practice many social queries are to find matches of a specific pattern node, rather than the entire M(Q;G). This paper studies top-k graph pattern matching. (1) We revise graph pattern matching defined in terms of simulation, by supporting a designated output node uo. Given G and Q, it is to find those nodes in M(Q;G) that match uo, instead of the large set M(Q;G). (2)We study two classes of functions for ranking the matches: relevance functions r() based on, e.g., social impact, and distance functions d() to cover diverse elements. (3) We develop two algorithms for computing top-k matches of uo based on r(), with the early termination property, i.e., they find top-k matches without computing the entire M(Q;G). (4)We also study diversified

top-k matching, a bi-criteria optimization problem based on both r() and d(). We show that its decision problem is NP-complete. Nonetheless, we provide an approximation algorithm with performance guarantees and a heuristic one with the early termination property. (5) Using real-life and synthetic data, we experimentally verify that our (diversified) top-k matching algorithms are effective, and outperform traditional matching algorithms in efficiency.

top-k matching, a bi-criteria optimization problem based on both r() and d(). We show that its decision problem is NP-complete. Nonetheless, we provide an approximation algorithm with performance guarantees and a heuristic one with the early termination property. (5) Using real-life and synthetic data, we experimentally verify that our (diversified) top-k matching algorithms are effective, and outperform traditional matching algorithms in efficiency.

Original language | English |
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Pages (from-to) | 1510-1521 |

Number of pages | 12 |

Journal | Proceedings of the VLDB Endowment (PVLDB) |

Volume | 6 |

Issue number | 13 |

Publication status | Published - 2013 |