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Selected Publications

• with Jelle Hellings, Marc Gyssens, Dirk Van Gucht: The power of Tarski's relation algebra on trees. J. Log. Algebraic Methods Program. 126: 100748 (2022)
• with Jelle Hellings, Dirk Van Gucht, Marc Gyssens: Optimizing Multiset Relational Algebra Queries Using Weak-Equivalent Rewrite Rules. FoIKS 2022: 187-205
• with Jelle Hellings, Catherine L. Pilachowski, Dirk Van Gucht, and Marc Gyssens. "From Relation Algebra to Semi-join Algebra: An Approach to Graph Query Optimization". the Computer Journal 64(5): 789-811 (2021).
• with Jelle Hellings. "Stab-Forests: Dynamic Data Structures for Efficient Temporal Query Processing". TIME 2020: 18:1-18:19
• with Kaijie Zhu, George H. L. Fletcher, Nikolay Yakovets, Odysseas Papapetrou. "Scalable temporal clique enumeration". SSTD 2019: 120-129
• "Path Query". Encyclopedia of Database Systems (2nd ed.) 2018
• Jelle Hellings, Marc Gyssens, and Dirk Van Gucht: “The Power of Tarski's Relation Algebra on Trees,” in Foundations of Information and Knowledge Systems 2018: 244-264.
• with Mayukh Das, Tushar Khot, Kristian Kersting, and Sriraam Natarajan, “Scaling Lifted Probabilistic Inference and Learning via Graph Databases,” SIAM International Conference on Data Mining, 2016. 738-746.
• with George H. L. Fletcher, Marc Gyssens, Jan Paredaens, and Dirk Van Gucht: “Structural characterizations of the navigational expressiveness of relation algebras on a tree,” Journal of Computer and System Science. 82(2): 229-259 (2016).
• with George H. L. Fletcher, Marc Gyssens, Dirk Leinders, Dimitri Surinx, Jan Van den Bussche, Dirk Van Gucht, and Stijn Vansummeren. “Relative expressive power of navigational querying on graphs”. Information Science. 298: 390-406 (2015)
• with Xin Shuai, Xiaozhong Liu, Tian Xia, and Chun Guo. “Comparing the Pulses of Categorical Hot Events in Twitter and Weibo”. 25th ACM Conference on Hypertext and Social Media. 2014.
• with Dirk Van Gucht, Marc Gyssens, and Jan Paredaens, “A Study of a Positive Fragment of Path Queries: Expressiveness, Normal Form and Minimization”. In Dataspace: The Final Frontier, 26th British National Conference on Databases, pp. 133-145. July, 2009. Best Paper Award.
• with Jignesh Patel, and H. V. Jagadish. Using Histograms to Estimate Answer Size for XML Queries. In Information Systems – Special Issue: Best Papers from EDBT 2002, 28 (1-2): 33-59, 2003.

Research Grants

• XPS: EXPL: FP: Symmetric Queries as a Building Block for Efficient Parallel Query Evaluation. NSF. 2015-2020. $297,592. PI.
• Empowering Health Care with Innovative Technologies of the Semantic Web. Indiana University Faculty Research Support Program (FRSP). 2010-2011, $46541. Co-PI.
• Asian American Students and Access to Higher Education. Summer Research Grant, College of Art and Sciences, Indiana University, 2009-2010. $8,000. Co-PI.
• ACXESS: Access Control for XML with Enhanced Security Specification. Indiana University Faculty Research Support Program (FRSP). 2005-2006, $30,600. PI.
• Chemical Informatics and Cyber infrastructure Collaboration program. NIH. 2004- 2007. $731,750. Senior Participant.