Search results for "Dynamic"

A TOPOLOGICAL STUDY OF PLANAR VECTOR FIELD SINGULARITIES A tribute to Ivar Bendixson

2019

In this paper one extends results of Bendixson [B] and Dumortier [D] about the germs of vector fields with an isolated singularity at the origin of IR 2 , not accumulated by periodic orbits. As new tool, one introduces minimal curves, which are curves surrounding the origin, with a minimal number of contact points with the vector field. Moreover, the arguments are essentially topological, with no use of a desingularization theory, as it is the case in [D]. 2000 Mathematics Subject Classification : 34C05, 34A26.

Estabilización de modelos económicos dinámicos con control óptimo en tiempo continuo

1990

En esta Tesis de Licenciatura se lleva a cabo el estudio de un problema determinado de optimización dinámica y sus aplicaciones en el campo de la Ciencia Económica. Un problema de optimización consiste, fundamentalmente, en la búsqueda de un extremo de una función o un funcional objetivo que proporcione un máximo o un mínimo para esa función. Cuando se habla de optimización dinámica hay que incorporar el factor tiempo al problema, en todas y cada una de las diferentes variables que intervienen, lo que afectará a los modelos matemáticos que se empleen para representar el comportamiento y las relaciones existentes entre dichas variables. También afecta al funcional objetivo a optimizar. Así, …

Computational methods and theory for ion channel research

2022

Ion channels are fundamental biological devices that act as gates in order to ensure selective ion transport across cellular membranes; their operation constitutes the molecular mechanism through which basic biological functions, such as nerve signal transmission and muscle contraction, are carried out. Here, we review recent results in the field of computational research on ion channels, covering theoretical advances, state-of-the-art simulation approaches, and frontline modeling techniques. We also report on few selected applications of continuum and atomistic methods to characterize the mechanisms of permeation, selectivity, and gating in biological and model channels.

Towards an efficient meshfree solver

2016

In this paper we focus on the enhancement in accuracy approximating a function and its derivatives via smoothed particle hydrodynamics. We discuss about improvements in the solution by reformulating the original method by means of the Taylor series expansion and by projecting with the kernel function and its derivatives. The accuracy of a function and its derivatives, up to a fixed order, can be simultaneously improved by assuming them as unknowns of a linear system. The improved formulation has been assessed with gridded and scattered data points distribution and the convergence has been analyzed referring to a case study in a 2D domain.

Synthetic Inertia Impact on Inter-Area Oscillations of the Continental Europe Power System

2020

The overall kinetic energy reduction due to increasing share of converter-interfaced generation (CIG) has been investigated so far by several works for systems of different types and sizes. The so called synthetic inertia is one of the most common and reviewed solutions to the issue of system inertia reduction. The paper investigates the effects of synthetic inertia as frequency service provided by the CIG sources for the Continental Europe (CE) synchronous area using a detailed large scale dynamic model. The model - provided in the basic form by the System Protection & Dynamics (SP&D) group of the ENTSOE - is properly developed substituting a determined amount of synchronous machin…

Current Accounts and Coordination of Wage Bargaining

2018

This study provides novel evidence on the impact of labor market institutions on current account dynamics. Our results suggest that a high degree of coordination of wage bargaining has a positive effect on the current account balance over the long run. This result is not driven entirely by wage moderation induced by centralized wage setting. We also provide robust evidence that a high degree of coordination of wage bargaining is associated with a slower current account adjustment toward its long-run equilibrium. This result seems theoretically plausible; the aggregate shocks in the exporting sector are largely driven by idiosyncratic shocks and the presence of idiosyncratic shocks increases…

Essays on current account imbalances

2017

Global current account imbalances and intra-euro area imbalances have been at the forefront of academic and policy debates for the last ten years. This thesis examines the determinants of current account balances and external adjustment. It consists of an introduction and four empirical studies. This thesis highlights the importance of institutional factors such as differences in national cultures and cross-country differences in the coordination of wage bargaining on external balances. The first study investigates the effects of deep determinants on current account balances. The point estimates are economically and statistically significant, suggesting that countries populated by Roman Cat…

Modulating the Self-assembly of Block Copolymers by Selective Cyclodextrins

2009

Modulating the self-assembly of thermosensitive block copolymers by selective cyclodextrins

2009

Constraining the pass-band of future space-based coronagraphs for observations of solar eruptions in the FeXIV 530.3 nm “green line”

2017

This research has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 647214) and from the UK Science and Technology Facilities Council. Observations of the solar corona in the FeXIV 530.3 nm “green line” have been very important in the past, and are planned for future coronagraphs on-board forthcoming space missions such as PROBA-3 and Aditya. For these instruments, a very important parameter to be optimized is the spectral width of the band-pass filter to be centred over the “green line”. Focusing on solar eruptions, motions occurring along the line of sight will Doppler shift the line prof…