scholarly journals Convex relaxation techniques for set-membership identification of LPV systems

Author(s):  
V. Cerone ◽  
D. Piga ◽  
D. Regruto
Automatica ◽  
2013 ◽  
Vol 49 (9) ◽  
pp. 2853-2859 ◽  
Author(s):  
Vito Cerone ◽  
Dario Piga ◽  
Diego Regruto

2020 ◽  
Vol 87 ◽  
pp. 27-36 ◽  
Author(s):  
Yiming Wan ◽  
Vicenç Puig ◽  
Carlos Ocampo-Martinez ◽  
Ye Wang ◽  
Eranda Harinath ◽  
...  

2014 ◽  
Vol 25 (5) ◽  
pp. 735-760 ◽  
Author(s):  
Damiano Rotondo ◽  
Fatiha Nejjari ◽  
Vicenç Puig ◽  
Joaquim Blesa

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7358
Author(s):  
Yuval Alfassi ◽  
Daniel Keren ◽  
Bruce Reznick

We study the Perspective-n-Point (PNP) problem, which is fundamental in 3D vision, for the recovery of camera translation and rotation. A common solution applies polynomial sum-of-squares (SOS) relaxation techniques via semidefinite programming. Our main result is that the polynomials which should be optimized can be non-negative but not SOS, hence the resulting convex relaxation is not tight; specifically, we present an example of real-life configurations for which the convex relaxation in the Lasserre Hierarchy fails, in both the second and third levels. In addition to the theoretical contribution, the conclusion for practitioners is that this commonly-used approach can fail; our experiments suggest that using higher levels of the Lasserre Hierarchy reduces the probability of failure. The methods we use are mostly drawn from the area of polynomial optimization and convex relaxation; we also use some results from real algebraic geometry, as well as Matlab optimization packages for PNP.


2015 ◽  
Vol 24 (3-4) ◽  
pp. 129-143
Author(s):  
André A. Keller

AbstractThis paper introduces constructing convex-relaxed programs for nonconvex optimization problems. Branch-and-bound algorithms are convex-relaxation-based techniques. The convex envelopes are important, as they represent the uniformly best convex underestimators for nonconvex polynomials over some region. The reformulation-linearization technique (RLT) generates linear programming (LP) relaxations of a quadratic problem. RLT operates in two steps: a reformulation step and a linearization (or convexification) step. In the reformulation phase, the constraint and bound inequalities are replaced by new numerous pairwise products of the constraints. In the linearization phase, each distinct quadratic term is replaced by a single new RLT variable. This RLT process produces an LP relaxation. The LP-RLT yieds a lower bound on the global minimum. LMI formulations (linear matrix inequalities) have been proposed to treat efficiently with nonconvex sets. An LMI is equivalent to a system of polynomial inequalities. A semialgebraic convex set describes the system. The feasible sets are spectrahedra with curved faces, contrary to the LP case with polyhedra. Successive LMI relaxations of increasing size yield the global optimum. Nonlinear inequalities are converted to an LMI form using Schur complements. Optimizing a nonconvex polynomial is equivalent to the LP over a convex set. Engineering application interests include system analysis, control theory, combinatorial optimization, statistics, and structural design optimization.


2019 ◽  
Vol 64 (5) ◽  
pp. 2092-2099 ◽  
Author(s):  
Ye Wang ◽  
Zhenhua Wang ◽  
Vicenc Puig ◽  
Gabriela Cembrano

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