Lap-Kei Lee Email: lklee 'at' madalgo.au.dk Research Interests Design and analysis of algorithms, especially in data stream algorithms and online job scheduling. Publications: [Conference papers] [Journal papers] [Informal papers];  Talks;  Teaching;  Recent positions;  Education

Publications

Conference papers:

• H. L. Chan, S. H. Chan, T. W. Lam, L. K. Lee, and J. Zhu.
  Non-clairvoyant weighted flow time scheduling with rejection penalty.
  To appear in Proceedings of the 24th Annual ACM Symposium on Parallelism in Algorithms and Architectures (SPAA), 2012.
  
  
• H. L. Chan, T. W. Lam, L. K. Lee, J. Pan, H. F. Ting, and Q. Zhang.
  Edit distance to monotonicity in sliding windows.
  In Proceedings of the 22nd International Symposium on Algorithms and Computation (ISAAC), pages 564-573, 2011.
  
  
• S. H. Chan, T. W. Lam, L. K. Lee, C. M. Liu, and H. F. Ting.
  Sleep management on multiple machines for energy and flow time.
  In Proceedings of the 38th International Colloquium on Automata, Languages and Programming (ICALP), pages 219-231, 2011.
  
  
• S. H. Chan, T. W. Lam, and L. K. Lee.
  Scheduling for weighted flow time and energy with rejection penalty.
  In Proceedings of the 28th International Symposium on Theoretical Aspects of Computer Science (STACS), pages 392-403, 2011.
  
  
• S. H. Chan, T. W. Lam, and L. K. Lee.
  Non-clairvoyant speed scaling for weighted flow time.
  In Proceedings of the 18th Annual European Symposium on Algorithms (ESA), pages 23-35, 2010.
  
  
• H. L. Chan, T. W. Lam, L. K. Lee, and H. F. Ting.
  Continuous monitoring of distributed data streams over a time-based sliding window.
  In Proceedings of the 27th International Symposium on Theoretical Aspects of Computer Science (STACS), pages 179-190, 2010.
  
  
• S. H. Chan, T. W. Lam, L. K. Lee, H. F. Ting, and P. Zhang.
  Non-clairvoyant scheduling for weighted flow time and energy on speed bounded processors.
  In Proceedings of the 16th Computing: the Australasian Theory Symposium (CATS), pages 3-10, 2010.
  
  
• H. L. Chan, T. W. Lam, L. K. Lee, and H. F. Ting.
  Approximating frequent items in asynchronous data stream over a sliding window.
  In Proceedings of the 7th Workshop on Approximation and Online Algorithms (WAOA), pages 49-61, 2009.
  
  
• T. W. Lam, L. K. Lee, H. F. Ting, I. K. K. To, and P. W. H. Wong.
  Sleep with guilt and work faster to minimize flow plus energy.
  In Proceedings of the 36th International Colloquium on Automata, Languages and Programming (ICALP), pages 665-676, 2009.
  
  
• H. L. Chan, J. Edmonds, T. W. Lam, L. K. Lee, A. Marchetti-Spaccamela, and K. Pruhs.
  Nonclairvoyant speed scaling for flow and energy.
  In Proceedings of the 26th International Symposium on Theoretical Aspects of Computer Science (STACS), pages 255-264, 2009.
  
  
• T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Speed scaling functions for flow time scheduling based on active job count.
  In Proceedings of the 16th Annual European Symposium on Algorithms (ESA), pages 647-659, 2008.
  
  
• N. Bansal, H. L. Chan, T. W. Lam, and L. K. Lee.
  Scheduling for speed bounded processors.
  In Proceedings of the 35th International Colloquium on Automata, Languages and Programming (ICALP), pages 409-420, 2008.
  
  
• T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Competitive non-migratory scheduling for flow time and energy.
  In Proceedings of the 20th Annual ACM Symposium on Parallelism in Algorithms and Architectures (SPAA), pages 256-264, 2008.
  
  
• T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Energy efficient deadline scheduling in two processor systems.
  In Proceedings of the 18th International Symposium on Algorithms and Computation (ISAAC), pages 476-487, 2007.
  
  
• H. L. Chan, W. T. Chan, T. W. Lam, L. K. Lee, K. S. Mak, and P. W. H. Wong.
  Energy efficient online deadline scheduling.
  In Proceedings of the 18th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pages 795-804, 2007.
  
  
• L. K. Lee, and H. F. Ting.
  A simpler and more efficient deterministic scheme for finding frequent items over sliding windows.
  In Proceedings of the 25th ACM SIGMOD-SIGACT-SIGART Symposium on Principles of Database Systems (PODS), pages 290-297, 2006.
  
  
• L. K. Lee, and H. F. Ting.
  Maintaining significant stream statistics over sliding windows.
  In Proceedings of the 17th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pages 724-732, 2006.
  
  
• S. M. Yiu, S. W. Yiu, L. K. Lee, E. K. Y. Li, and M. C. L. Yip.
  Sharing and access right delegation for confidential documents: a practical solution.
  In Proceedings of the 15th Australasian Conference on Information Systems (ACIS), 2004.
  
  

Journal papers:

• T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Online speed scaling based on active job count to minimize flow plus energy.
  Accepted to Algorithmica.
  
  
• H. L. Chan, T. W. Lam, L. K. Lee, and H. F. Ting.
  Continuous monitoring of distributed data streams over a time-based sliding window.
  Algorithmica, 62(3-4):1088-1111, 2012.
  
  
• T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Improved multi-processor scheduling for flow time and energy.
  Journal of Scheduling, 15(1):105-116, 2012.
  
  
• H. F. Ting, L. K. Lee, H. L. Chan, and T. W. Lam.
  Approximating frequent items in asynchronous data stream over a sliding window.
  Algorithms, 4(3):200-222, 2011.
  
  
• S. H. Chan, T. W. Lam, L. K. Lee, H. F. Ting, and P. Zhang.
  Non-clairvoyant scheduling for weighted flow time and energy on speed bounded processors.
  Chicago Journal of Theoretical Computer Science (Special issue for CATS 2010), 2011-1, 2011.
  
  
• H. L. Chan, J. Edmonds, T. W. Lam, L. K. Lee, A. Marchetti-Spaccamela, and K. Pruhs.
  Nonclairvoyant speed scaling for flow and energy.
  Algorithmica, 61(3):507-517, 2011.
  
  
• X. Han, T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Deadline scheduling and power management for speed bounded processors.
  Theoretical Computer Science, 411(40-42):3587-3600, 2010.
  
  
• R. Y. S. Hung, L. K. Lee, and H. F. Ting.
  Finding frequent items over sliding windows with constant update time.
  Information Processing Letters, 110(7):257-260, 2010.
  
  
• H. L. Chan, J. W. T. Chan, T. W. Lam, L. K. Lee, K. S. Mak, and P. W. H. Wong.
  Optimizing throughput and energy in online deadline scheduling.
  ACM Transactions on Algorithms, 6(1):10, 2009.
  
  
• T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Non-migratory multi-processor scheduling for response time and energy.
  IEEE Transactions on Parallel and Distributed Systems (Special issue on power-aware parallel and distributed systems), 19(11):1527-1539, 2008.
  
  
• S. M. Yiu, S. W. Yiu, L. K. Lee, E. K. Y. Li, and M. C. L. Yip.
  Sharing and access right delegation for confidential documents: a practical solution.
  Information and Management, 43(5):607-616, 2006.
  
  

Informal papers:

• H. L. Chan, T. W. Lam, L. K. Lee, J. Pan, H. F. Ting, and Q. Zhang.
  Edit distance to monotonicity in sliding windows.
  The 3rd Workshop on Massive Data Algorithmics (MASSIVE), 2011.
  
  
• X. Han, T. W. Lam, L. K. Lee, I. K. K. To, and P. W. H. Wong.
  Deadline scheduling and power management for speed bounded processors.
  The 9th Workshop on Models and Algorithms for Planning and Scheduling Problems (MAPSP), 2009.
  
  

Talks

• Edit distance to monotonicity in sliding windows.
  MADALGO Seminar, Aarhus University, Aarhus, Denmark, December 2011.
  
  
• Scheduling for weighted flow time and energy with rejection penalty.
  The 28th International Symposium on Theoretical Aspects of Computer Science (STACS), Dortmund, Germany, March 2011.
  
  
• Non-clairvoyant speed scaling for weighted flow time.
  The 18th Annual European Symposium on Algorithms (ESA), Liverpool, UK, September 2010.
  
  
• Energy-efficient job scheduling.
  The 4th Workshop of Working Group "Great Road - Network of the Greater Region for Operational Research and Decision Support Systems", Saarbrücken, Germany, April 2010.
  
  
• Continuous monitoring of distributed data streams over a time-based sliding window.
  The 27th International Symposium on Theoretical Aspects of Computer Science (STACS), Nancy, France, March 2010.
  
  
• Speed scaling to manage flow time and energy.
  Bristol Algorithms Days 2010 Feasibility Workshop, Bristol, UK, February 2010.
  
  
• Continuous monitoring of distributed data streams over a time-based sliding window.
  Noon Seminar, Max Planck Institute for Informatics, Saarbrücken, Germany, February 2010.
  
  
• Sleep with guilt and work faster to minimize flow plus energy.
  The 36th International Colloquium on Automata, Languages and Programming (ICALP), Rhodes, Greece, July 2009.
  
  
• Deadline scheduling and power management for speed bounded processors.
  The 9th Workshop on Models and Algorithms for Planning and Scheduling Problems (MAPSP), Abbey Rolduc, The Netherlands, June 2009.
  
  
• Sleep with guilt and work faster to minimize flow plus energy.
  Noon Seminar, Max Planck Institute for Informatics, Saarbrücken, Germany, June 2009.
  
  
• Continuous monitoring of distributed data streams over a time-based sliding window.
  Theory Seminar, The Hong Kong University of Science and Technology, Hong Kong, May 2009.
  
  
• Maintaining significant stream statistics over sliding windows.
  The 17th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), Miami, US, January 2006.
  
  
• A time- and space-optimal algorithm for Significant One's Counting over sliding windows and its application to frequency estimation.
  Departmental research seminar, The University of Hong Kong, Hong Kong, August 2005.
  
  

Teaching

• Spring 2011 (MADALGO): Streaming Algorithms.
  
  

Recent Positions

• Apr 2011 - Mar 2012:
  Postdoctoral researcher, MADALGO Center for Massive Data Algorithmics, Aarhus, Denmark.
  
  
• Dec 2009 - Mar 2011:
  Postdoctoral researcher, Max Planck Institute for Informatics, Saarbrücken, Germany.
  
  
• Jun 2009 - Nov 2009:
  Postdoctoral fellow, University of Hong Kong, Hong Kong.
  
  

Education

• Feb 2006 - May 2009:
  Ph.D. in Computer Science, University of Hong Kong. (Advisor: Professor Tak-Wah Lam)
  
  
• Sep 2004 - Jan 2006:
  M.Phil. in Computer Science (transferred to Ph.D.), University of Hong Kong. (Advisor: Dr Hing-Fung Ting)
  
  
• Sep 2001 - Aug 2004:
  B.Eng. (First Class Honours) in Computer Engineering, University of Hong Kong.