The dynamics of transitional flows are governed by an interplay between the non-normal linear and quadratic nonlinearity in incompressible Navier-Stokes equations. In this work, we propose a framework for nonlinear stability analysis that exploits fact flow interactions constrained physics encoded nonlinearity. particular, show problems can be posed as convex feasibility optimization based on L...

A class of quadratic optimization problems in Hilbert spaces is considered, where pointwise box constraints and constraints of bottleneck type are given. The main focus is to prove the existence of regular Lagrange multipliers in L-spaces. This question is solved by investigating the solvability of a Lagrange dual quadratic problem. The theory is applied to different optimal control problems fo...

A model is proposed for a class of asynchronous sample-and-hold operators that relevant to the analysis embedded and networked systems. The parametrized by characteristics corresponding time-varying input–output delay. Uncertainty in relationship between timing zero-order-hold update events at output possibly aperiodic sampling input means delay does not always reset fixed value. This distinct ...

We consider the problem of minimizing an indefinite quadratic objective function subject to twosided indelinite quadratic constraints. Under a suitable simultaneous diagonalization assumption {which trivially holds for trust region type problems), we prove that the original problem is equivalent to a convex minimization problem with simple linear constraints. We then consider a special problem ...

Ultralight dark matter is a compelling candidate. In this work, we examine the impact of quadratically-coupled ultralight on predictions Big Bang Nucleosynthesis. The presence can modify effective values fundamental constants during Nucleosynthesis, modifying predicted abundances primordial elements such as Helium-4. We improve upon existing literature in two ways: firstly, take into account th...

In this paper a global optimization algorithm for solving sum of quadratic ratios problem with coefficients and nonconvex quadratic function constraints (NSP ) is proposed. First, the problem NSP is converted into an equivalent sum of linear ratios problem with nonconvex quadratic constraints ( LSP ). Using linearization technique, the linearization relaxation of LSP is obtained. The whole prob...