RESEARCH

with Boris Mordukhovich, Mau Nam Nguyen and Tuyen Tran

The paper presents a new approach to solve multifacility location problems, which is based on mixed integer programming and algorithms for minimizing differences of convex (DC) functions. The main challenges for solving the multifacility location problems under consideration come from their intrinsic discrete, nonconvex, and nondifferentiable nature. We provide a reformulation of these problems as those of continuous optimization and then develop a new DC type algorithm for their solutions involving Nesterov's smoothing. The proposed algorithm is computationally implemented via MATLAB numerical tests on both artificial and real data sets.

with Warren Hare and  Yves Lucet 

Computing explicitly the {\epsilon}-subdifferential of a proper function amounts to computing the level set of a convex function namely the conjugate minus a linear function. The resulting theoretical algorithm is applied to the the class of (convex univariate) piecewise linear-quadratic functions for which existing numerical libraries allow practical computations. We visualize the results in a primal, dual, and subdifferential views through several numerical examples. We also provide a visualization of the Brøndsted-Rockafellar Theorem.

Work-in-Progress:

DC Programming Algorithm for  Fully Convex Bilevel Optimization 

with Boris MordukhovichAlain Zemkoho, and Vuong Phan

Solving a Continuous Max-Min Problem by DC Algorithms 

with Boris Mordukhovich, Mau Nam Nguyen and Tuyen Tran

Solving Linear Complimentarity  Problem involving hidden-Z matrices

with S.K.Neogy, Gambheer Singh and Sajal Ghosh