Byron CHOI (Koon Kau) in ( Traditional Chinese and in Pinyin)

Associate Professor

Programme Director of BSc in Computer Science (JS2510)

Department of Computer Science (Map)
Faculty of Science

Hong Kong Baptist University


Contact Information:

Office: Room 628

David C Lam Building (DLB628)

Hong Kong Baptist University

Kowloon Tong, Hong Kong

Tel: (+852) 3411 7638

Fax: (+852) 3411 7892

Email:  choi at / bchoi at



General Information:

I obtained my Ph.D and MSE degrees in Computer and Information Science from the University of Pennsylvania in 2006 and 2001, respectively. I received my Bachelor of Engineering degree (with the first-class honours) in Computer Engineering from the Hong Kong University of Science and Technology (HKUST). I was awarded the IEEE (Hong Kong Section) prize in 1999. Before joining the Hong Kong Baptist University, I was an Assistant Professor with School of Computer Engineering / Nanyang Technological University (NTU) for three happy years (2005 - 2008). I was a research associate at the University of Edinburgh in 2005 and a summer student intern for the Galax project at AT&T Labs Florham Park. I visited HKUST theoretical computer science group in 2003. I am a member of ACM, IEEE Computer Society and IEEE Technical Committee of Data Engineering (TCDE).

I am a member of Database Group at HKBU. I received the distinguished reviewer award from VLDB 2019. I was a recipient of the HKBU President's Award for Outstanding Young Researcher 2016, the Department's Best Service Award in 2020 and 2018, Best Teaching Award in 2015 and Best Research Award in 2014. I served as the director of a Croucher Foundation Advanced Study Institute (ASI) titled "Frontiers in Big Data Graph Research" 2015. I served as a reviewer of the Austrian Science Fund (FWF) 2014. I served as a supervisor of Hong Kong Scholars Program 2020.

Looking for strong applicants for Postdocs, PhD students and research assistants:

  • Applicants may have good background in (but not limited to) mathematics, algorithms and programming. Priorities are given to those who have backgrounds on graph data management or securities. The research assistant positions are immediately available for one year and extensible for multiple years based on performance and availability of funds. My selected publications can be found here. An example of possible research topic can be found here. Our experience on providing secure subgraph query services can be found here. The general information of database research at HKBU can be found here. For enquiries, please contact bchoi at

Research Interests (Selected Publications):

  • Graph-structured databases
  • Database security
  • Time series analysis
  • User interfaces for database systems
  • Incremental maintenance algorithms and view updates

PhD Graduates:

  • Jiaxin Jiang, 2020. (First appointment: Postdoc Research Fellow, Database Group, Hong Kong Baptist University, Hong Kong SAR)
  • Peipei Yi, 2018. (First appointment: Data Scientist, Machine Intelligence Center, Lenovo, Hong Kong SAR)
  • Zhe Fan, 2015. (First appointment: Big Data Analyst Engineer at Huawei, Shenzhen, China)
  • Yun Peng, 2013. (First appointment: Research fellow at Nanyang Technological University, Singapore)

General Research Funds (GRF) in the capacity of Principle Investigator (PI):

  • Semantic Indexing for Keyword Search on Graphs (HKBU12201119, 2020-2022, on-going)
  • Exploring the Structural Critical Entities in Big Attributed Graphs (HKBU12201518, 2019-2021, transferred from Dr. Zhiwei Zhang, on-going)
  • Privacy-preserving Linear Algebra Framework for Graph Query Algorithms for Massive Networks (HKBU12232716, 2017-2019, on-going)
  • Exploratory Search on Graph Databases through Subgraph Query Feedback (HKBU12201315, 2016-2018, completed)
  • Adaptive Filtering for Efficient Subgraph Isomorphism in Graph Databases (HKBU210510, 2011-2012, completed)
  • Optimizations for the View Update Problem with Emerging Applications (HKBU210409, 2010-2011, completed)

Selected Recent Projects:



Program Committee (Partial):

  • PVLDB 2022-2021, 2019-2018 and 2015, SIGMOD 2021-2020, ICDE 2021, CIKM 2021 (senior PC), PAKDD 2020, ER 2019, 2015, CIKM (tutorial) 2015, WWW (demo) 2014, CloudDb 2014, IEEE Big Data Science and Engineering (BDSE 2014), IEEE BigData Congress 2014-2013, DEXA 2014-2008, IEEE BDDS2013, DASFAA 2013-2011, APWeb/WAIM 2010-2007, SIGMOD IDAR 2008, ICDE 2008, CIKM 2008, ...

External Reviewer (Partial):

  • VLDB, ICDE, TODS, VLDBJ, TOIS, TKDE, TKDD, DAPD, Journal of Supercomputing, Information Sciences, Information Systems, ER, ...

Local Organizing Committee:

  • PRIB 2007

Selected Publications (full list at DBLP):

  • L. Xu, J. Jiang, B. Choi, J. Xu, and S. S. Bhowmick. Privacy Preserving Strong Simulation Queries on Large Graphs. ICDE, 2021. (to appear) [pdf]
  • G. Li, B. Choi, J. Xu, S. S. Bhowmick, K-P Chun and G. L-H. Wong. ShapeNet: A Shapelet-Neural Network Approach for Multivariate Time Series Classification. AAAI, 2021. (to appear) [Implementation!][Poster at EASL, the International Liver Congress (ILC) 2021]
  • Y. Peng, B. Choi and J. Xu. Graph Edit Distance Learning via Modeling Optimum Matchings with Constraints. IJCAI, 2021. (to appear)
  • G. Li, B. Choi, J. Xu, S. S. Bhowmick, K-P Chun and G. L-H. Wong. Efficient Shapelet Discovery for Time Series Classification. TKDE, 2020. (to appear) [pdf] [Implementation!] [Visualet: a demo at CIKM '20]
  • J. Jiang, X. Huang, B. Choi, J. Xu, S. S. Bhowmick, and L. Xu. PPKWS: An Efficient Framework for Keyword Search on Public-Private Networks. ICDE 2020, Pages 457-468. [pdf] [Implementation!]
  • P. Yi , B. Choi, Z. Zhang, S. S. Bhowmick and J. Xu. GFocus: User Focus-based Graph Query Autocompletion. TKDE, 2020. [pdf]
  • J. Jiang, B. Choi, S. S. Bhowmick and J. Xu. A Generic Ontology Framework for Indexing Keyword Search on Massive Graphs. TKDE, 2019. [pdf] [Implementation!]
  • P. Yi, B. Choi, S. S. Bhowmick and J. Xu. AutoG: A Visual Query Autocompletion Framework for Graph Databases. The VLDB Journal 26(3):347-372, 2017. (the demo at VLDB '16)
  • S. S. Bhowmick, B. Choi and C. Dyreson. Data-driven Visual Graph Query Interface Construction and Maintenance: Challenges and Opportunities [Vision]. PVLDB 9(13): 1505-1508, 2016.
  • Y. Peng, B. Choi, B. He, S. Zhou, R. Xu and X. Yu. VColor: A Practical Vertex-cut Based Approach for Coloring Large Graphs. ICDE 2016, Pages 97-108.
  • J. Jiang, P. Yi, B. Choi, Z. Zhang and X. Yu. Privacy-Preserving Reachability Query Services for Massive Networks. CIKM 2016, Pages 145-154.
  • Z. Fan, B. Choi, J. Xu and S. S. Bhowmick. Asymmetric Structure-Preserving Subgraph Query for Large Graphs. ICDE 2015. Pages 339-350. [pdf] [Implementation!]
  • Z. Fan, B. Choi, Q. Chen, J. Xu, H. Hu and S. S. Bhowmick. Structure-Preserving Subgraph Query Services. TKDE 27(8): 2275-2290 (2015). [pdf]
  • Y. Peng, Z. Fan, B. Choi, J. Xu and S. S. Bhowmick. Authenticated Subgraph Similarity Search in Outsourced Graph Databases. TKDE 27(7): 1838-1860 (2015). [pdf]
  • D. Wu, B. Choi, J. Xu and C. S. Jensen. Authentication of Moving Top-k Spatial Keyword Queries. TKDE 27(4):922-935 (2015). [pdf]
  • Z. Fan, Y. Peng, B. Choi, J. Xu and S. S. Bhowmick. Towards Efficient Authenticated Subgraph Query Service in Outsourced Graph Databases. TSC 7(4):696-713, 2014. [pdf]
  • Y. Peng, B. Choi, J. Xu, H. Hu and S. S. Bhowmick. Side-Effect Estimation: A Filtering Approach to the View Update Problem. TKDE 26(9):2307-2322 (2014). [pdf]
  • J. Deng, B. Choi, J. Xu, H. Hu and S. S. Bhowmick. Incremental Maintenance of the Minimum Bisimulation of Cyclic Graphs. TKDE 25(11): 2536-2550 (2013). [pdf]
  • S. S. Bhowmick, B. Choi and S. Zhou. VOGUE: Towards a Visual Interaction-aware Graph Query Processing Framework. CIDR 2013.
  • L. Song, Y. Peng, B. Choi, J. Xu and B. He. Spectral Decomposition for Optimal Graph Index Prediction. PAKDD 2013. Pages 187-200.
  • Y. Peng, B. Choi and J. Xu. Selectivity Estimation of Twig Queries on Cyclic Graphs. ICDE 2011. Pages 960-971.
  • H. Hu, C. Ren, J. Xu and B. Choi. Processing Private Queries over Untrusted Data Cloud through Privacy Homomorphism. ICDE 2011. Pages 601-612.
  • L. Zhu, A. Sun and B. Choi. Detecting Spam-Blogs from Blog Search Results. IPM 2011 47(2): 246-262.
  • B. Choi, H. Hu, J. Xu, W. Cheung, C. H. Li and J. Liu. Data Engineering in Graph Databases. ISCIS 2010. Pages 127 - 132. (invited paper)
  • R. Bramandia, B. Choi and W-K. Ng. Incremental Maintenance of 2-hop Labeling of Large Graphs. TKDE 22(5): 682-698 (2010).
  • C. Jin, S. S. Bhowmick, X. Xiao, J. Cheng and B. Choi. GBLENDER: Towards Blending Visual Query Formulation and Query Processing in Graph Databases. SIGMOD 2010. Pages 111-122.
  • M. Cheng, B. Choi and W. Cheung. Hiding Emerging Patterns with Local Recoding Generalization. PAKDD 2010. Pages 158 - 170.
  • R. Bramandia, J. Cheng, B. Choi and J. X. Yu. Optimizing Updates of Recursive XML Views of Relations. The VLDB Journal 18(5):1313-1333, 2009.
  • R. Bramandia, B. Choi and W-K. Ng. On Incremental Maintenance of 2-hop Labeling of Graphs. WWW 2008. Pages 845-854. [pdf]
  • B. Choi, G. Cong, W. Fan and S. D. Viglas. Updating Recursive XML Views of Relations. JCST 23(4): 516-537 July 2008.
  • N. Tang, J. X. Yu, M. T. Ozsu, B. Choi and K-F. Wong. Multiple Materialized View Selection for XPath Query Rewriting. ICDE 2008. Pages 873-882.
  • B. He, Q. Luo and B. Choi. Adaptive Index Utilization in Memory-Resident Structural Joins. TKDE 19(6): 772 - 788 (2007).
  • B. Choi, G. Cong, W. Fan and S. D. Viglas. Updating Recursive XML Views of Relations. ICDE 2007. Pages 766 - 775.
  • B. He, Q. Luo and B. Choi. Cache-Conscious Automata for XML Filtering. TKDE 18(12): 1629-1644 (2006).
  • Z. Lin, B. He, and B. Choi. A Quantitative Summary of XML Structures. ER 2006. Pages 228-240. LNCS 4215. [pdf] Springer-Verlag.
  • B. Choi. Document Decomposition for XML Compression: A Heuristic Approach. DASFAA 2006. Pages 202-217. LNCS 3382
  • P. Buneman, B. Choi, W. Fan, R. Hutchison, R. Mann and S. D. Viglas. Vectorizing and Querying Large XML Repositories. ICDE 2005. Pages 261-272. [pdf]
  • B. He, Q. Luo and B. Choi. Cache-Conscious Automata for XML Filtering. ICDE 2005. Pages 878-889. [pdf]
  • P. Bohannon, B. Choi and W. Fan. Incremental Evaluation of Schema-Directed XML Publishing. SIGMOD 2004. Pages 503-514. [pdf]
  • B. Choi, W. Fan, X. Jia, and A. Kasprzyk. A Uniform System for Publishing and Maintaining XML Data. VLDB 2004 (demo). Pages 1301-1304.
  • B. Choi, M. Mahoui and D. Wood. On the Optimality of Holistic Algorithms for Twig Queries. DEXA 2003. Pages 28-37. LNCS 2736. [pdf] Springer-Verlag.
  • M. Fernandez, J. Simeon, B. Choi, A. Marian, G. Sur. Implementing Xquery 1.0: The Galax Experience. VLDB 2003 (demo). Pages 1077-1080.
  • B. Choi. What are Real DTDs Like? WebDB 2002. Pages 43-48. [pdf]

Book Chapter:

  • R. Chen, X. Weng, B. He, B. Choi and M. Yang. Network Performance Aware Graph Partitioning for Large Graph Processing Systems in the Cloud. Large Scale and Big Data: Processing and Management. S. Sakr and M. M. Gaber (Eds.), to be published by CRC Press, 2013 [an earlier version published in SoCC '12]. [Book Link] [Amazon Link]

Filed U.S. Patents:

Selected Presentations:

  • B. Choi. Vectorising and Querying large XML Repositories: Can XML query language be as effective as SQL? Informatics Jamboree 2004 Poster Competition at University of Edinburgh.
  • P. Buneman and B. Choi. Vectorising and Querying XML. National e-Science Institute, Edinburgh. April, May 2004.
  • B. Choi, M. Mahoui and D. Wood. On the Optimality of the Holistic Twig Join Algorithm. DIMACS Working Group on Streaming Data II. March 2003.  (abstract)

Technical Reports:

  • B. Choi, M. Fernandez and J. Simeon. The XQuery Formal Semantics: A Foundation for Implementation and Optimization. Technical Report MS-CIS-02-25, University of Pennsylvania, 2002.
  • B. Choi, M. Mahoui and D. Wood. The Optimality of Holistic Algorithms for XPath. 2003. [pdf]

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