Representative Publications 
Combinatorial
Optimization
 - Zhi-Yong Liu, Hong Qiao,
     and Lei Xu (2012),  “An Extended Path Following
     Algorithm for Graph-Matching Problem,” IEEE Transactions on Pattern Analysis and Machine Intelligence,
     Vol.34(7):pp1451-1456, 2012.
 - Lei Xu (2010), "Machine learning problems from
     optimization perspective", A special issue for CDGO 07, Journal of Global Optimization, 47,
     2010, 369–401.
- Lei Xu (2007), `` One-Bit-Matching Theorem for ICA, Convex-Concave
     Programming on Polyhedral Set, and Distribution Approximation for
     Combinatorics
     ",  Neural Computation, 19:
     546-569. 2007 .
- Lei Xu and E.Oja (1989),
     ``Improved Simulated Annealing, Boltzmann Machine and Attributed Graph
     Matching", in G.Goos and J.Hartmanis eds., Lecture Notes in
     Computer Sciences, Vol.412, Springer-Verlag, pp.151-160.
- Lei Xu and Irwin
     King, (2001), ``A PCA approach for fast retrieval of structural patterns
     in attributed graphs", IEEE Transactions on Systems, Man and
     Cybernetics, Part B, Vol. 31, No. 5 , Oct. 2001, pp 812 -817.
- Lei Xu (1994)``Combinatorial Optimization Neural Nets Based on A
     Hybrid of Lagrange and Transformation Approaches", 1994 Proc. of
     World Congress on Neural Networks, June 4-9, 1994, SanDiego, CA,
     Vol.II, 399-404,
- Lei Xu (1995)``On The Hybrid LT Combinatorial Optimization: New
     $U$-Shape Barrier, Sigmoid Activation, Least Leaking Energy and Maximum
     Entropy", Proc. 1995 Intl Conf. on Neural Information Processing
     (ICONIP95), Oct 30 - Nov. 3, Beijing,
     Vol. I, pp309-312.
- Lei Xu
     (2003), ``Distribution Approximation, Combinatorial Optimization, and
     Lagrange-Barrier", Proceedings of International Joint Conference
     on Neural Networks 2003 (IJCNN '03)}, July 20-24, 2003, Jantzen
     Beach, Portland, Oregon,
     pp2354-2359.
- SUN Ke; TU Shikui; DAVID Yang Gao and Lei Xu (2009).  "Canonical
     Dual Approach to Binary Factor Analysis".  Lecture Notes
     in Computer Science 5441 ed. by Adali, T.; Jutten, C.; Romano,
     J.M.T.; Barros, A.K. . pp.346-353. /Heidelberg, Springer .March, 2003.Berlin.
- S.M. Chan, K.M. Lau and Lei Xu (1995), ``Comparison on the Hopfield
     scheme and the Hybrid Lagrange and Transformation Approaches for Solving
     the Traveling Salesman Problem", Proc. of 1995 Intl IEEE Symposium
     on Intelligence in Neural and Biological Systems, May 29-31,1995,
     Washington DC, USA, IEEE Computer Society Press, pp209-218.
- Chuangyin Dang and Lei Xu
     (2001), ``A Lagrange Multiplier and Hopfield-Type Barrier Function Method
     for the Traveling Salesman Problem", Neural Computation, Vol. 14 ,
     No. 2, pp303 - 324.
- Chuangyin Dang and Lei Xu
     (2001), ``A globally convergent Lagrange and barrier function iterative
     algorithm for the traveling salesman problem", Neural Networks,
     Vol.14, No.2, pp217-230, 2001.
- Chuangyin Dang and Lei Xu
     (2000), ``A barrier function method for the nonconvex quadratic
     programming problem with box constraints", Journal of Global
     Optimization, Vol.18, No.2, 2000, pp 165-188.