Optimization of Fishing Strategies in Space and Time as a Non-convex Optimal Control Problem

The behavior of a fishing fleet and its impact onto the biomass of fish can be described by a nonlinear parabolic diffusion–reaction equation. Looking for an optimal fishing strategy leads to a non-convex optimal control problem with a bilinear control action. In this work, we present such an optimal control formulation, prove its well-posedness and derive first- and second-order optimality conditions. These results provide a basis for tailored finite element discretization as well as for Newton type optimization algorithms. First numerical test problems show typical features as so-called No-Take-Zones and maximal fishing quota (total allowable catches) as parts of an optimal fishing strategy.     

A sharp integral inequality for closed spacelike submanifolds immersed in the de Sitter space

Archiv der Mathematik - In this paper, we establish a sharp integral inequality for n-dimensional closed spacelike submanifolds with constant scalar curvature immersed with parallel normalized mean...     

Modeling of Colloidal Crystallization of Cadmium Selenide

Colloid Journal - This article is devoted to the Monte Carlo simulation of the colloidal crystallization kinetics of cadmium selenide (CdSe) nanoparticles (NPs), i.e., the growth of nanoparticles...     

Isometric embeddings into Heisenberg groups

We study isometric embeddings of a Euclidean space or a Heisenberg group into a higher dimensional Heisenberg group, where both the source and target space are equipped with an arbitrary left-invariant homogeneous distance that is not necessarily sub-Riemannian. We show that if all infinite geodesics in the target are straight lines, then such an embedding must be a homogeneous homomorphism. We discuss a necessary and certain sufficient conditions for the target space to have this ‘geodesic linearity property’, and we provide various examples.     

Investigation of Physical Processes in the Gas Discharge Region Between Liquid Electrodes

Electrophysical, hydro-gas-dynamic, and thermal characteristics of a discharge arising between liquid electrodes are considered. Spatial visualization of flow patterns in the gas discharge region is performed by using the schlieren technique.     

Quasi-periodic bursters and chaotic dynamics in a shallow arch subject to a fast–slow parametric excitation

Nonlinear Dynamics - In this paper, various nonlinear dynamics of a one-degree-of-freedom shallow arch model are investigated. The arch is subject to an imposed displacement of its support that is...     

Synthesis and Antimicrobial Study of New Fused Thiazolo[3,2-b]triazine,Triazolo[4,3-b]triazine,and 1,2,4-Triazinone Derivatives

Russian Journal of Organic Chemistry - 6-[2-(Furan-2-yl)ethyl]-3-sulfanylidene-3,4-dihydro-1,2,4-triazin-5(2H)-one (1) reacted with chloroacetone to give S-acetonyl derivative which cyclized in...