This is the homepage of Tak-Wah Lam.

Tak-Wah Lam graduated with a BSc in Computer Science from the Chinese University of Hong Kong in 1984 and received his MS & PhD in Computer Science from the University of Washington in 1988.  Since then he has been with the University of Hong Kong.   He is now a professor in the Department of Computer Science.  He was an associate dean of the Faculty of Engineering from 2001 to 2006. He has received several teaching awards from the department and faculty, and more recently an outstanding supervisor award from the university.

Tak-Wah’s research is mainly on the design and analysis of algorithms for different applications.  His recent work is in the areas of data streams, online scheduling, compressed indexing, and computational biology.   Apart from theoretical work, he is also interested in building practical software.  Seven doctoral students have graduated under his supervision. Most of them become academics in Hong Kong or overseas.  In the future, Tak-Wah looks forward to working with motivated students from China (with background in computer science or mathematics), who would eventually contribute to the algorithms research of China.

Outside of work, he enjoys playing basketball, tennis and chess with his two sons, who are respectively 11 and 13 years old.   Due to his back & shoulder pain, he disciplines himself to go to the swimming pool regularly.  More recently, he has started to practice Tai Chi.

 

Algorithms post-doc at HKU: Applications are now invited for a postdoc fellow in algorithms.  The appointment can be one to three years.

 

Tracking Tak-Wah’s PhD students:

 

·       Lap-Kei Lee (2009): MPI, Germany

·       Alan S.L. Tam (2009): Apple, Hong Kong

·       Ho-Leung Chan (2007): U of Pittsburgh, USA >> MPI, Germany >> HKU

·       Wing-Kai Hon (2004): Purdue University, USA >> Tsing Hua University, Taiwan

·       Prudence W.H. Wong (2002): HKU >> U of Liverpool, UK

·       Isaac K.K. To (2000): HKU >> Outblaze, HK >> U of Liverpool, UK >> Cluster Technology, HK

·       Ken W.K. Sung (1998): Yale University, USA >> National U of Singapore, Singapore

·       Ka-Hing Lee (1996): Hewlett Packard, HK

·       Joe K.W. Chong (1995): Max Planck Institut Informatik, Germany >> HKU >> Cluster Technology, HK

 

Recent Publications (2005 -):
  (see DBLP for a full list)

Data Stream Algorithms:

Continuous monitoring of distributed data streams over a time-based sliding window. HL Chan, TW Lam, LK Lee, HF Ting.  STACS 2010.

 

Approximating frequent items in asynchronous data stream over a sliding window. H.L. Chan, T.W. Lam, L.K. Lee, and H.F. Ting.  WAOA 2009.

 

On-line Algorithms:

Non-clairvoyant scheduling for weighted flow time and energy on speed bounded processors. S.H. Chan, T.W. Lam, L.K. Lee, H.F. Ting, and P. Zhang. CATS, 2010.

 

Sleep with Guilt and Work Faster to Minimize Flow plus Energy. TW Lam, LK Lee, HF Ting, Isaac To and P Wong, ICALP 2009.

 

Nonclairvoyant Speed Scaling for Flow and Energy. HL Chan, J Edmonds, TW Lam, LK Lee, A. Marchetti-Spaccamela, STACS, 2009. pdf

 

Speed Scaling functions for flow time scheduling based on active job count. TW Lam, LK Lee, Isaac To and P Wong. ESA, 2008. pdf

 

Competitive Non-migratory Scheduling for Flow Time and Energy. TW Lam, LK Lee, Isaac To and P Wong.  SPAA, 2008. Postscript

 

Scheduling for bounded speed processors. N Bansal, HL Chan, TW Lam, LK Lee. ICALP 2008. Postscript

 

Energy efficient deadline scheduling in two processor systems. TW Lam, LK Lee, Isaac To and P Wong.  ISAAC, 2007, pp. 476-487.

 

Online deadline scheduling with bounded energy efficiency. WT Chan, TW Lam, KS Mak, and P Wong.  TAMC 2007, pp. 416-427.

 

Energy Efficient Online Deadline Scheduling.  HL Chan, WT Chan, TW Lam, LK Lee, KS Mak, and P Wong.  SODA 2007, pp. 795-804. Postscript

 

Extra unit-speed machine are almost as powerful as speedy machines for competitive flow time scheduling.  H.L. Chan, T.W. Lam and K.S. Liu.  SIAM Journal on Computing, 37(5): 1595-1612, 2008. A preliminary version appeared in SODA 2006.

New Resource Augmentation Analysis of the Total Stretch of SRPT and SJF in Multiprocessor Scheduling. W.T. Chan, T.W. Lam, K.S. Liu and P Wong. Theoretical Computer Science, volume 359(1-3): 430-439, 2006.  A preliminary version appeared in MFCS 2005. 

Dynamic Bin Packing of Unit Fractions Items. W.T. Chan, T.W. Lam and P Wong. In Proceedings of the 32nd International Colloquium on Automata, Languages and Programming (ICALP), 614-626, 2005.

Non-migratory Online Deadline Scheduling on Multiprocessors.  H.L. Chan, T.W. Lam and K.K. To.  SIAM Journal on Computing, 34(3): 669-682, 2005.  A preliminary version appeared in SODA 04.

On-line Stream Merging with Max Span and Min Coverage.  WT Chan, TW Lam, HF Ting and P Wong. Theory of Computing Systems, 38(4) [a special issue for selected papers of CIAC 03]: 461-479, 2005.

A Tighter Extra-Resource Analysis of Online Deadline Scheduling.  TW Lam, TW Ngan and KK To.  Journal of Combinatorial Optimization, 9(2): 157-165, 2005.

 

Compressed Indexing Data Structures:

            Succinct Index for Dynamic Dictionary Matching.  W.K. Hon, T.W. Lam, R. Shah, S.L. Tam, J. Vitter.  ISAAC 2009.

 

            Succinct Text Indexing with Wildcards.  S.L. Tam, E. Wu, T.W. Lam, S.M. Yiu. SPIRE 2009, pp. 39-50

 

Compressed Index for Dictionary Matching. W.K. Hon, T.W. Lam, R. Shah, S.L. Tam, J. Vitter.  IEEE DCC 2008, pp. 23-32.

 

Space Efficient Indexes for String Matching with Don't Cares. T.W. Lam, W.K. Sung, S.L. Tam & S.M. Yiu.  ISAAC 2007, pp. 846-857.

 

Compressed Indexing and Local Alignment of DNA.  T.W. Lam, W.K. Sung, S.L. Tam, C.K. Wong & S.M. Yiu.  In Proceedings of the first International Conference on Combinatorial Optimization and Applications (COCOA), pp. 242-254, 2007.  Bioinformatics. 24(6): 791-797, 2008.

 

Cache-Oblivious Index for Approximate String Matching. W.K. Hon, T.W. Lam, R. Shah, S.L. Tam, J. Vitter.  In Proceedings of the 17th Annual Symposium on Combinatorial Pattern Matching (CPM), 2007, pp. 40-51. .

 

A Space and Time Efficient Algorithm for Constructing Compressed Suffix Arrays. W.K. Hon, TW Lam, K Sadakane, and WK Sung. Algorithmica 2007 (online version).

 

Compressed Indexes for Dynamic Text Collections. HL Chan, WK Hon, TW Lam and K Sadakane.  ACM Transactions on Algorithms (TALG), 3(2): article 21, 2007 (online version).

 

Compressed Indexes for Approximate String Matching.  HL Chan, TW Lam, WK Sung, SL Tam, SS Wong.  In Proceedings of the 14th Annual European Symposium on Algorithms (ESA), 2006, pp. 208-219.

 

A linear size Index for Approximate Pattern Matching. HL Chan, TW Lam, WK Sung, SL Tam, SS Wong. In Proceedings of the 17th Annual Symposium on Combinatorial Pattern Matching (CPM), 2006, pp. 49-59.

 

Improved Approximate String Matching Using Compressed Suffix Data Structures. T.W. Lam, W.K. Sung, S.S. Wong. Algorithmica 2007 (onine version).  A preliminary version appeared in ISAAC 2005.

 

Dynamic Dictionary Matching and Compressed Suffix Trees. H.L. Chan, W.K. Hon, T.W. Lam, and K. Sadakane.  In Proceedings of the 16th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), 2005, pp. 13-22. 

Approximate String Matching Using Compressed Suffix Arrays. T.N.D. Huynh, W.K. Hon, T.W. Lam, W.K. Sung.  Theoretical Computer Science 352(1-3): 240-249, 2006. Postscript.   A preliminary version appeared in CPM 04.

 

Computational Biology:

        High Throughput Short Read Alignment via Bi-directional BWT.  T.W. Lam, R.  Li, A. Tam, S. Wong, E. Wu, and S.M. Yiu.  BIBM 2009.

 

A Memory Efficient Algorithm for Structural Alignment of RNAs with Embedded Simple Pseudoknots.  T. Wong, Y.S. Chiu, T.W. Lam and S.M. Yiu.  5th Asia-Pacific Bioinformatics Conference (APBC) 2008.

 

Finding Alternative Splicing Patterns with Strong Support from Expressed Sequences. International Conference on Bioinformatics and Computational Biology (BIOCOMP), 2007. Also to appear in Journal of Bioinformatics and Computational Biology 2008.

 

Correcting Short Reads with High Error Rates for Improved Sequencing Result. T. Wong, P.Y. Chan, T.W. Lam, S.M. Yiu. To appear in International Journal of Bioinformatics Research and Applications 2008.

 

A More Accurate and Efficient Whole Genome Phylogeny.  P.Y. Chan, T.W. Lam, S.M. Yiu, and C.M. Liu.  In Proceedings of the Asia Pacific Bioinformatics Conference (APBC), 2006, pp. 337-352.

Reconstructing an Ultrametric Galled Phylogenetic Network from a Distance Matrix H.L. Chan, J. Jansson, T.W. Lam and S.M. Yiu.  30th International Symposium on Mathematical Foundations of Computer Science (MFCS), 2005, pp. 224-235.  Journal of Bioinformatics and Computational Biology 4(4): 807-832, 2006.

Filtering of ineffective siRNAs and improved siRNA design Tool. P. Wong, T.W. Lam, Y.C. Mui, S.M. Yiu, H.F. Kung, and M Lin. Bioinformatics 21(2): 144-151 (2005).  A preliminary version appeared in APBC 04.

A Mutation-Sensitive Approach for Locating Conserved Gene Pairs between Related Species. H.L. Chan, T.W. Lam, W.K. Sung, P Wong, S.M. Yiu.  Bioinformatics 21(10): 2271-2278 (2005). A preliminary version appeared in BIBE 04.

Finding Motifs for insufficient number of sequences with strong binding to transcription factor. F.Y.L. Chin, H.C.M. Leung, S.M. Yiu, T.W. Lam, R. Rosenfeld, W.W. Tsang, David K. Smith, Y. Jiang, RECOMB 2004, pp. 125-132.

An Efficient Algorithm for Opitmizing Whole Genome Alignment with Noise. TW Lam, N Lu, HF Ting, WH Wong, SM Yiu Bioinformatics 20(16): 2676-2684, 2004.  A preliminary version appeared in ISAAC 03.

 

Software for biological applications: Compressed indexing for DNA, exact matching, short read alignment and local alignment ; whole genome alignment.

Recent Program Committee Membership:

    • 2009: 7th Asia-Pacific Bioinformatics Conference (APBC), 9th Workshop on Models and Algorithms for Planning and Scheduling Problems (MAPSP), Workshop on Pattern Recognition in Bioinformatics (PRIB)
    • 2007: 5th Asia-Pacific Bioinformatics Conference (APBC); 2nd International Conference on Algorithmic Aspects in Information and Management (AAIM); SPIRE.
    • 2006: Workshop on Pattern Recognition in Bioinformatics (PRIB); 2nd International Conference on Algorithmic Aspects in Information and Management (AAIM); 3rd RECOMB Satellite Workshop on Regulatory Genomics.
    • 2005: 16th Annual Symposium on Combinatorial Pattern Matching (CPM); 3rd Asia-Pacific Bioinformatics Conference (APBC); International Workshop on Data Mining and Bioinformatics (DMBIO).
    • 2004: 15th International Symposium on Algorithms and Computation (ISAAC).

E-mail: twlamcs.hku.hk
By post: Department of Computer Science, University of Hong Kong, Pokfulam Road, Hong Kong
Office: Room 409, Chow Yei Ching Building
Tel: 2859 2172; Fax: 2559 8447