This is
  • Leong Hou U
  • 余亮豪
  • Ryan
from UM
Associate Professor
State Key Laboratory of Internet of Things for Smart City
Department of Computer and Information Science
Faculty of Science and Technology

Other Positions and Services

I am actively seeking individuals with a strong passion for Large Scale Data Processing, Graph Learning, and Reinforcement Learning to join my research team. If you are a research assistant, PhD student, or postdoc who is enthusiastic about these fields and eager to contribute to cutting-edge research, I encourage you to reach out. We offer an exciting research environment in our State Key Laboratory and Super Intelligent Computing Center.

Academic Qualification

∞ Ph.D. in Computer Science, 
The University of Hong Kong, Hong Kong (2010)

∞ M.Sc. in E-Commerce Technology,
University of Macau, Macau (2005)

∞ B.Sc. in Computer Science and Information Engineering,
National Chi Nan University, Taiwan (2003)

Research Interests

Large-Scale Spatial and Spatio-Temporal Data | Large-Scale Graph Data Processing | Large-Scale Graph Neural Networks | Large-Scale Data Visualization Techniques | Crowdsourcing |  Reinforcement Learning | Information Retrieval | Optimization Problems

Contact Detail

E11-4021
Faculty of Science and Technology
University of Macau
Telephone: (853) 8822-4493
Email: ryanlhu [at] um [dot] edu [dot] mo

Selected Publications

Journal Articles

  1. Siyuan Wu, Leong Hou U, Panagiotis Karras: k-Best Egalitarian Stable Marriages for Task Assignment, Proc. VLDB Endow. 2023 (Accepted)
  2. Ming YANG, Leong Hou U: MixLight: Mixed-agent Cooperative Reinforcement Learning for Traffic Light Control. IEEE Transactions on Industrial Informatics. (Accepted)
  3. Jian Zeng , Leong Hou U , Xiao Yan , Yan Li , Mingji Han , Bo Tang: Extracting Top-k Frequent and Diversified Patterns in Knowledge Graphs. IEEE Trans. Knowl. Data Eng. (Accepted)
  4. Hanlin Li, Xiaowei Wu, Leong Hou U, Kun Pang Kou: Near-Optimal Scheduling for Crowdsourced Transit System With Skip-Stop Tactic.  IEEE Trans. Knowl. Data Eng. (Accepted)
  5. Tsz Nam Chan, Leong Hou U, Reynold Cheng, Man Lung Yiu, Shivansh Mittal: Efficient Algorithms for Kernel Aggregation Queries. IEEE Trans. Knowl. Data Eng. 34(6): 2726-2739 (2022)
  6. Liqing Zhang, Leong Hou U, Mingliang Zhou, Zhenning Li: An Intelligent Train Operation Method Based on Event-Driven Deep Reinforcement Learning. IEEE Trans. Ind. Informatics 18(10): 6973-6980 (2022)
  7. Tsz Nam Chan, Leong Hou U, Yun Peng, Byron Choi, Jianliang Xu: Fast Network K-function-based Spatial Analysis. Proc. VLDB Endow. 15(11): 2853-2866 (2022)
  8. Tsz Nam Chan, Pak Lon Ip, Kaiyan Zhao, Leong Hou U, Byron Choi, Jianliang Xu: LIBKDV: A Versatile Kernel Density Visualization Library for Geospatial Analytics. Proc. VLDB Endow. 15(12): 3606-3609 (2022)
  9. Binbin Zhang, Hao Wang, Leong Hou U: Dynamic top-k influence maximization in social networks. GeoInformatica 26(2): 323-346 (2022)
  10. Tsz Nam Chan, Pak Lon Ip, Leong Hou U, Byron Choi, Jianliang Xu. SWS: A Complexity-Optimized Solution for Spatial-Temporal Kernel Density Visualization. Proceedings of the VLDB Endowment (PVLDB), 2022. (project page)
  11. Tsz Nam Chan, Pak Lon Ip, Leong Hou U, Byron Choi, Jianliang Xu. SAFE: A Share-and-Aggregate Bandwidth Exploration Framework for Kernel Density Visualization. Proceedings of the VLDB Endowment (PVLDB), 2022. (project page)
  12. Tsz Nam Chan, Pak Lon Ip, Leong Hou U, Weng Hou Tong, Shivansh Mittal, Ye Li, Reynold Cheng: KDV-Explorer: A Near Real-Time Kernel Density Visualization System for Spatial Analysis. Proc. VLDB Endow. 14(12): 2655-2658 (2021) (project page)
  13. Tsz Nam Chan, Zhe Li, Leong Hou U, Jianliang Xu, Reynold Cheng: Fast Augmentation Algorithms for Network Kernel Density Visualization. Proc. VLDB Endow. 14(9): 1503-1516 (2021)
  14. Tsz Nam Chan, Man Lung Yiu, Leong Hou U: The Power of Bounds: Answering Approximate Earth Mover’s Distance with Parametric Bounds. IEEE Trans. Knowl. Data Eng. 33(2): 768-781 (2021)
  15. Yan Li, Hao Wang, Ngai Meng Kou, Leong Hou U & Zhiguo Gong: Crowdsourced top-k queries by pairwise preference judgments with confidence and budget control. The VLDB Journal (2021)
  16. Yiyang Yang, Sucheng Deng, Juan Lu, Yuhong Li, Zhiguo Gong, Leong Hou U, Zhifeng Hao: GraphLSHC: Towards large scale spectral hypergraph clustering. Inf. Sci. 544: 117-134 (2021)
  17. Huaizhong Lin, Shanshan Wu, Leong Hou U, Ngai Meng Kou, Yunjun Gao, Dongming Lu: Finding the hottest item in data streams. Inf. Sci. 430: 314-330 (2018)
  18. Leong Hou U, Junjie Zhang, Kyriakos Mouratidis, Ye Li: Continuous Top-k Monitoring on Document Streams. IEEE Trans. Knowl. Data Eng. 29(5): 991-1003 (2017) [link]
  19. Yuhong Li, Leong Hou U, Man Lung Yiu, Zhiguo Gong: Efficient discovery of longest-lasting correlation in sequence databases. VLDB J. 25(6): 767-790 (2016) [link]
  20. Bailong Liao, Leong Hou U, Man Lung Yiu, Zhiguo Gong: Beyond Millisecond Latency kNN Search on Commodity Machine. IEEE Trans. Knowl. Data Eng. 27(10): 2618-2631 (2015) [link]
  21. Ngai Meng Kou, Leong Hou U, Yiyang Yang, and Zhiguo Gong: Travel Topic Analysis: A Mutually Reinforcing Method for Geo-tagged Photos, Geoinformatica, to appear. [pdf]
  22. Shen Ge, Leong Hou U, Nikos Mamoulis, David W. Cheung: Dominance relationship analysis with budget constraints. Knowl. Inf. Syst. (KAIS) 42(2):409-440 (2015)
  23. Yiyang Yang, Zhiguo Gong, Leong Hou U: Identifying Points of Interest using heterogenous Features. ACM TIST (TIST) 5(4):68 (2014). [pdf]
  24. Leong Hou U, Hong Jun Zhao, Man Lung Yiu, Yuhong Li, Zhiguo Gong: Towards Online Shortest Path Computation. IEEE Trans. Knowl. Data Eng. (TKDE) 26(4):1012-1025 (2014) [pdf]
  25. Shen Ge, Leong Hou U, Nikos Mamoulis, David W. Cheung: Efficient All Top-k Computation – A Unified Solution for All Top-k, Reverse Top-k and Top-m Influential Queries. IEEE Trans. Knowl. Data Eng. 25(5): 1015-1027 (2013)
  26. Leong Hou U, Kyriakos Mouratidis, Man Lung Yiu, and Nikos Mamoulis. Optimal Matching between Spatial Datasets under Capacity Constraints. ACM Transactions on Database Systems, 35(2):44 pages, April 2010.
  27. Leong Hou U, Kyriakos Mouratidis, and Nikos Mamoulis. Continuous Spatial Assignment of Moving Users. VLDB Journal, 19(2):141-160, 2010.
  28. Leong Hou U, Nikos Mamoulis, and Man Lung Yiu. Computation and Monitoring of Exclusive Closest Pairs. IEEE Trans. Knowl. Data Eng., 20(12):1641-1654, 2008.

Book Chapters

  1. Leong Hou U, Optimal Matching Between Spatial Datasets. Encyclopedia of GIS 2017: 1505-1511

Refereed Conference Proceedings

  1. Yiming Wang, Ming Yang, Renzhi Dong, Binbin Sun, Leong Hou U, Furui Liu: Efficient Potential-based Exploration in Reinforcement Learning using Inverse Dynamic Bisimulation Metric. Advances in Neural Information Processing Systems 36: Annual Conference on Neural Information Processing Systems 2023 (NeurIPS 2023).
  2. Danni Ren, Leong Hou U and Wei Liu: Dual-view Contrastive Learning for Auction Recommendation. CIKM 2023 (accepted)
  3. Tsz Nam Chan, Leong Hou U, Byron Choi, Jianliang Xu, Reynold Cheng: Large-scale Geospatial Analytics: Problems, Challenges, and Opportunities. SIGMOD Conference Companion 2023: 21-29
  4. Tsz Nam Chan, Rui Zang, Pak Lon Ip, Leong Hou U, Jianliang Xu: PyNKDV: An Efficient Network Kernel Density Visualization Library for Geospatial Analytic Systems. SIGMOD Conference Companion 2023: 99-102
  5. Ming Yang, Renzhi Dong, Yiming Wang, Furui Liu, Yali Du, Mingliang Zhou, Leong Hou U: TieComm: Learning a Hierarchical Communication Topology Based on Tie Theory. DASFAA (1) 2023: 604-613
  6. Wei Liu, Leong Hou U, Shangsong Liang, Huaijie Zhu, Jianxing Yu, Yubao Liu, Jian Yin: Revisiting Positive and Negative Samples in Variational Autoencoders for Top-N Recommendation. DASFAA (2) 2023: 563-573
  7. Rongqin Chen, Shenghui Zhang, Leong Hou U, Ye Li. Redundancy-Free Message Passing for Graph Neural Networks. Advances in Neural Information Processing Systems 35: Annual Conference on Neural Information Processing Systems 2022 (NeurIPS 2022).
  8. Bo Tang, Jian Zeng, Qiandong Tang, Chuan Yang, Qiaomu Shen, Leong Hou U, Xiao Yan, Dan Zeng: CheetahKG: A Demonstration for Core-based Top-$k$ Frequent Pattern Discovery on Knowledge Graphs. ICDE 2022: 3134-3137
  9. Tsz Nam Chan, Leong Hou U, Byron Choi, Jianliang Xu. SLAM: Efficient Sweep Line Algorithms for Kernel Density Visualization. Proceedings of ACM Conference on Management of Data (SIGMOD), 2022. (project page)
  10. Siyuan Wu and Leong Hou U, Tracking the Evolution: Discovering and Visualizing the Evolution of Literature, DASFAA 2022.
  11. Jian Zeng, Leong Hou U, Xiao Yan, Mingji Han, Bo Tang: Fast Core-based Top-k Frequent Pattern Discovery in Knowledge Graphs. ICDE 2021: 936-947
  12. Hanlin Li, Xiaowei Wu, Leong Hou U, Kun Pang Kou: Near-Optimal Fixed-Route Scheduling for Crowdsourced Transit System. ICDE 2021: 2273-2278
  13. Yinong Zhu, Yong Feng, Mingliang Zhou, Baohua Qiang, Leong Hou U, Jiajie Zhu: Distribution-Aware Hierarchical Weighting Method for Deep Metric Learning. ICASSP 2021: 1770-1774
  14. Yu Zhou, Yong Feng, Mingliang Zhou, Baohua Qiang, Leong Hou U, Jiajie Zhu: Deep Adversarial Quantization Network for Cross-Modal Retrieval. ICASSP 2021: 4325-4329
  15. Caihua Shan, Leong Hou U, Nikos Mamoulis, Reynold Cheng: A Toolkit for Managing Multiple Crowdsourced Top-K Queries. CIKM 2020: 3453-3456
  16. Caihua Shan, Leong Hou U, Nikos Mamoulis, Reynold Cheng, Xiang Li: A General Early-Stopping Module for Crowdsourced Ranking. DASFAA (2) 2020: 314-330
  17. Tsz Nam Chan, Man Lung Yiu, Leong Hou U: The Power of Bounds: Answering Approximate Earth Mover’s Distance with Parametric Bounds (Extended abstract). ICDE 2020: 2022-2023
  18. Tsz Nam Chan, Man Lung Yiu, Leong Hou U: KARL: Fast Kernel Aggregation Queries. ICDE 2019: 542-553 [pdf]
  19. Siyuan Wu, Leong Hou U, Sourav S. Bhowmick, Wolfgang Gatterbauer: PISTIS: A Conflict of Interest Declaration and Detection System for Peer Review Management. SIGMOD Conference 2018: 1713-1716. [project page]
  20. Yan Li, Ngai Meng Kou, Hao Wang, Leong Hou U, Zhiguo Gong: A Confidence-Aware Top-k Query Processing Toolkit on Crowdsourcing. PVLDB 10(12): 1909-1912 (2017). [project page]
  21. Ye Li, Leong Hou U, Man Lung Yiu, Ngai Meng Kou: An Experimental Study on Hub Labeling based Shortest Path Algorithms. PVLDB 11(4): 445-457 (2017) [project page]
  22. Yiyang Yang, Zhiguo Gong, Qing Li, Leong Hou U, Ruichu Cai, Zhifeng Hao: A Robust Noise Resistant Algorithm for POI Identification from Flickr Data. IJCAI 2017: 3294-3300.
  23. Ngai Meng Kou, Yan Li, Hao Wang, Leong Hou U, Zhiguo Gong: Crowdsourced Top-k Queries by Confidence-Aware Pairwise Judgments. SIGMOD Conference 2017: 1415-1430. [project page]
  24. Yuhong Li, Bo Tang, Leong Hou U, Man Lung Yiu, Zhiguo Gong: Fast Subsequence Search on Time Series Data. EDBT 2017: 514-517.
  25. Shanshan Wu, Huaizhong Lin, Leong Hou U, Yunjun Gao, Dongming Lu: Finding Frequent Items in Time Decayed Data Streams. APWeb (2) 2016: 17-29.
  26. Bo Tang, Man Lung Yiu, Yuhong Li, Leong Hou U: Exploit Every Cycle: Vectorized Time Series Algorithms on Modern Commodity CPUs. ADMS/IMDM@VLDB 2016: 18-39.
  27. Ngai Meng Kou, Leong Hou U, Nikos Mamoulis, Yuhong Li, Ye Li, and Zhiguo Gong: A Topicbased Reviewer Assignment System. In Proceedings of VLDB2015 (demo paper).
  28. Ngai Meng Kou, Leong Hou U, Nikos Mamoulis, and Zhiguo Gong: Weighted Coverage based Reviewer Assignment. In Proceedings of SIGMOD2015. [project page]
  29. Yuhong Li, Leong Hou U, Man Lung Yiu, and Zhiguo Gong: Quick-Motif: An Efficient and Scalable Framework for Exact Motif Discovery. In Proceedings of ICDE2015. [project page]
  30. Yuhong Li, Leong Hou U, Man Lung Yiu, Zhiguo Gong: Discovering Longest-lasting Correlation in Sequence Databases. PVLDB 6(14):1666-1677 (2013) [pdf]
  31. Yu Tang, Leong Hou U, Yilun Cai, Nikos Mamoulis, Reynold Cheng: Earth Mover’s Distance based Similarity Search at Scale. PVLDB 7(4):313-324 (2013) [pdf]
  32. Yiyang Yang, Zhiguo Gong, and Leong Hou U. Identifying points of interest by self-tuning clustering. In SIGIR, 2011.
  33. Man Lung Yiu, Leong Hou U, Simonas Saltenis, and Kostas Tzoumas. Efficient proximity detection among mobile users via self-tuning policies. PVLDB, 3(1):985–996, 2010.
  34. Leong Hou U, Nikos Mamoulis, Klaus Berberich, and Srikanta J. Bedathur. Durable top-k search in document archives. In SIGMOD Conference, pages 555–566, 2010.
  35. Leong Hou U, Nikos Mamoulis, and Kyriakos Mouratidis. A fair assignment algorithm for multiple preference queries. VLDB, 2(1):1054-1065, 2009.
  36. Leong Hou U, Nikos Mamoulis, and Kyriakos Mouratidis. Efficient evaluation of multiple preference queries. In ICDE, pages 1251-1254, 2009.
  37. Leong Hou U, Man Lung Yiu, Kyriakos Mouratidis, and Nikos Mamoulis. Capacity constrained assignment in spatial databases. In SIGMOD Conference, pages 15-28, 2008.

Check here for my DBLP record.

I am looking for research assistants, PhD students, and postdocs who intend to study on premier research (cf. Arnetminer, CCF, or Core) in Data Engineering.MixLight: Mixed-agent Cooperative Reinforcement Learning for Traffic Light Control

Teaching

M.Sc. Courses

  • CISC7201 Introduction to Data Science Programming (Fall 2019, Fall 2020, Fall 2021, Fall 2022, Fall 2023)
  • COIS724. Big Data Processing and Analysis (Fall 2015, Fall 2016, Fall 2017, Spring 2019, Spring 2020, Spring 2021, Spring 2022, Spring 2023)
  • CISC7015. Advanced Topics in Computer Science I – Blockchain Technology and Applications (Spring 2019)
  • COIS704. Current Development in Database (Fall 2014)
  • ECOM703. Distributed Database Management (Fall 2014)
  • ECOM706. Data Warehousing (Spring 2011, Spring 2012, Spring 2013)

B.Sc. Courses

  • The ACM-ICPC International Collegiate Programming Contest (ACM ICPC) Training (Coordinator and Coach, 2016-present)
  • CISB410. Final Year Project (Coordinator, 2010-present)
  • CISC7201. Introduction to Data Science Programming (Fall 2018)
  • CISB363. Information Retrieval and Web Mining (Spring 2014, Spring 2015, Spring 2016, Spring 2017, Spring 2018)
  • CISB359. Information Systems Analysis and Design (Fall 2011, Fall 2012, Fall 2013)


Technical Activities

Reviewer for journals

  • IEEE Transactions on Knowledge and Data Engineering (IEEE TKDE)
  • Very Large Data Base Journal (VLDBJ)
  • ACM Transactions on Spatial Algorithms and Systems (ACM TSAS)
  • IEEE Transactions on Mobile Computing
  • IEEE Transactions on Intelligent Transportation
  • Information Systems (Inf. Syst.)

International Conference Technical Program/Review Committee and Session Chair

  • 2023: VLDB, ICDE, DASFAA, PAKDD, WISE, WAIM-APWeb
  • 2022: ICDE, DASFAA, PAKDD, CIKM, WISE, WAIM-APWeb
  • 2021: DASFAA, PAKDD, WAIM-APWeb
  • 2020: CIKM, DASFAA, PAKDD, WAIM-APWeb
  • 2019: DASFAA
  • 2018: WISE, PAKDD, WAIM
  • 2017: VLDB Demo, WAIM
  • 2016: CIKM (KM Track)
  • 2015: DASFAA, APWEB, CIKM (KM Track), SIGMOD/PODS PhD Symposium
  • 2014: CIKM (KM Track), DASFAA, WAIM, MobiGIS, WebDB
  • 2013: SIGMOD, CIKM (KM Track), WAIM
  • 2012: KDD, ER, MobiGIS

International Conference Steering/Organization Committee

Supervisions

Research Students

  • Liqing ZHANG (PhD)
  • Yiming WANG (PhD)
  • Shenghui ZHANG (PhD)
  • Binbin SUN (PhD)
  • Shungran ZHANG (PhD)
  • Xu LI (PhD)
  • Paklon IP (PhD)
  • Siyuan WU (PhD, Graduated 2023, Now a PostDoc at SMU, Singapore), Enhancing Efficiency, Fairness, and Effectiveness in Task Assignments
  • Hanlin LI (PhD, co-supervised, Graduated 2023), Bus Service Design with Near-optimal Scheduling and Skip-stop Tactic
  • Paklon IP (MSc. Graduated 2023)
  • Danni REN (MSc. Graduated 2023)
  • Yiming WANG (MSc. Graduated 2022)
  • Yuxue SHI (MSc , Graduated 2021), Efficient Edge Computing Framework for Index Sharing Based Route Planning in Last-Mile Delivery
  • Wenyue MA (MSc, Graduated 2021), Trajectory-driven
    Optimizing Influential on Advertising Placement
  • Ye LI (PhD, Graduated 2021), Efficient query processing on very large networks
  • Yan LI (PhD, Graduated 2020), Quality Aware Crowdsourced Processing
  • Pei ZHANG (MSc, Graduated 2020), Crowdsourcing Top-k Processing by Prior Knowledge
  • Yuhao YOU (MSc, Graduated 2019), Overlapping community search with clique merge community model
  • Changyi MA (MSc, Graduated 2017), Functional Region based Daily-life Activity Recommendation
  • Xuan Liu RU (MSc, Graduated 2016), Link prediction in time-aware graphs
  • Yan LI (MSc, Graduated 2015), Crowdsourcing Object Ranking by Pairwise Comparisons
  • Jian WANG (MSc, Graduated 2015), Multidimensional Similarity Join using MapReduce
  • Junjie ZHANG (MSc, Graduated 2015), A Scalable Framework for Continuous Keyword Search Queries
  • Nana PAN (MSc, Graduated 2014), On Dynamic Top-k Influence Maximization
  • Bailong LIAO (MSc, Graduated 2014), Compact Main Memory Indexing for Efficient Spatial Network Queries
  • Bohan ZHAN (MSc, Graduated 2014), Influence Maximization on MapReduce

Final Year Projects

  • Jiajin ZHANG, Reinforcement Learning in Games (2022/2023) The best projects of CIS in 2022/2023
  • Minnie LO, E-Voting System based on Blockchain Technology (2021/2022) One of 5 best projects of CIS in 2021/2022
  • Iok Keong WONG and Kuok Hou HO, A Study of Reinforcement Learning Algorithms in CARLA (2020/2021) One of 5 best projects of CIS in 2020/2021
  • Jinrong LIANG and Jinxuan LIANG, CARLA: autonomous driving system based using machine learning techniques (2019/2020) One of 5 best projects of CIS in 2019/2020
  • Colby Kan, Hayden Lam, Johnson Ho, and Thomas Ho, Data-driven traffic simulation (2018/2019) One of 5 best projects of CIS in 2018/2019
  • Io Kei CHAN, Chi Kin LAO, Seng Cheong UN, and Kin Chong CHAN, Music Data Driven Virtual Reality Gaming System (2017/2018) The best projects of CIS in 2017/2018
  • Ka Lap SI and Manqi FANG, Big Traffic Data Analysis and Visualization (2017/2018) One of 5 best projects of CIS in 2017/2018
  • Ka Hei LEONG, Ka Chon LEONG, and Pui On KUAN, The Rise of Magnetic Positioning: An Emerging and Infrastructure Free Solution for Indoor Positioning (2016/2017) One of 5 best projects of CIS in 2016/2017
  • Wai Lon FAN and Ka Chon WONG, Big Data for Smart Transport – Augmented Reality based Transportation System (2016) One of 5 best projects of CIS in 2016
  • Renjie GOU and Jlio Mamad Bald Quina, Big Data for Smart Transport – Public Transportation Planning (2016)
  • Chi Lap PUN and Weng un IONG, Travel Route Recommendation System (2015) The best project of CIS in 2015
  • Kit NG, Mei Keong U, and Kin Fei WONG, Interactive TV System on Mobile Devices (2013)
  • Kun YAO, G-PathSim (2013) The runner-up project of CIS in 2013
  • Wai Kuan CHEANG, Keng Fai LEI, and Man Cheng HO, StallKet – Open your stall at anytime and anywhere (2012)
  • Mao Teng LAM and Ka Chon UN, A Study on Search and Visualization in DBLP (2012)