Search results for "volte"

A note on the uniqueness and attractive behavior of solutions for nonlinear Volterra equations

2001

In this paper we prove that positive solutions of some nonlinear Volterra integral equations must be locally bounded and global attractors of positive functions. These results complete previous results about the existence and uniqueness of solutions and their attractive behavior.

Noise-induced effects in population dynamics

2002

We investigate the role of noise in the nonlinear relaxation of two ecosystems described by generalized Lotka-Volterra equations in the presence of multiplicative noise. Specifically we study two cases: (i) an ecosystem with two interacting species in the presence of periodic driving; (ii) an ecosystem with a great number of interacting species with random interaction matrix. We analyse the interplay between noise and periodic modulation for case (i) and the role of the noise in the transient dynamics of the ecosystem in the presence of an absorbing barrier in case (ii). We find that the presence of noise is responsible for the generation of temporal oscillations and for the appearance of s…

A scalar Volterra derivative for the PoU-integral

2005

Nonmonotonic Pattern Formation in Three Species Lotka-Volterra System with Colored Noise

2005

A coupled map lattice of generalized Lotka-Volterra equations in the presence of colored multiplicative noise is used to analyze the spatiotemporal evolution of three interacting species: one predator and two preys symmetrically competing each other. The correlation of the species concentration over the grid as a function of time and of the noise intensity is investigated. The presence of noise induces pattern formation, whose dimensions show a nonmonotonic behavior as a function of the noise intensity. The colored noise induces a greater dimension of the patterns with respect to the white noise case and a shift of the maximum of its area towards higher values of the noise intensity.

Optimal Control of the Lotka-Volterra Equations with Applications

2022

In this article, the Lotka-Volterra model is analyzed to reduce the infection of a complex microbiote. The problem is set as an optimal control problem, where controls are associated to antibiotic or probiotic agents, or transplantations and bactericides. Candidates as minimizers are selected using the Maximum Principle and the closed loop optimal solution is discussed. In particular a 2d-model is constructed with 4 parameters to compute the optimal synthesis using homotopies on the parameters.

Some new fixed point theorems in Menger PM-spaces with application to Volterra type integral equation

2014

Abstract We establish some fixed point theorems by introducing two new classes of contractive mappings in Menger PM-spaces. First, we prove our results for an α - ψ -type contractive mapping and then for a generalized β -type contractive mapping. Some examples and an application to Volterra type integral equation are given to support the obtained results.

Hybrid coincidence and common fixed point theorems in Menger probabilistic metric spaces under a strict contractive condition with an application

2014

Abstract We prove some coincidence and common fixed point theorems for two hybrid pairs of mappings in Menger spaces satisfying a strict contractive condition. An illustrative example is given to support the genuineness of our extension besides deriving some related results. Then, we establish the corresponding common fixed point theorems in metric spaces. Finally, we utilize our main result to obtain the existence of a common solution for a system of Volterra type integral equations.

P-spaces and the Volterra property

2012

We study the relationship between generalizations of $P$-spaces and Volterra (weakly Volterra) spaces, that is, spaces where every two dense $G_\delta$ have dense (non-empty) intersection. In particular, we prove that every dense and every open, but not every closed subspace of an almost $P$-space is Volterra and that there are Tychonoff non-weakly Volterra weak $P$-spaces. These results should be compared with the fact that every $P$-space is hereditarily Volterra. As a byproduct we obtain an example of a hereditarily Volterra space and a hereditarily Baire space whose product is not weakly Volterra. We also show an example of a Hausdorff space which contains a non-weakly Volterra subspace…

Stochastic response of MDOF wind-excited structures by means of Volterra series approach

1998

Abstract The role played by the quadratic term of the forcing function in the response statistics of multi-degree-of-freedom (MDOF) wind-excited linear-elastic structures is investigated. This is accomplished by modeling the structural response as a Volterra series up to the second order and neglecting the wind-structure interaction. In order to reduce the computational effort due to the calculation of a large number of multiple integrals, required by the used approach, a recent model of the wind stochastic field is adopted.

La conoscenza: rilievi ed analisi

2009

Il contributo illustra criteri e fasi dell’indagine conoscitiva che è stata condotta nel corso dei lavori di restauro dei soffitti dipinti, a cantiere iniziato. Sono dettagliatamente descritte le metodologie e le operazioni di rilevamento e di analisi condotte con puntuali riferimenti agli strumenti impiegati. Il testo è corredato di alcune delle tavole tematiche prodotte per la perizia di variante, ed in particolare di quelle che restituiscono le informazioni quali-quantitative acquisite e l’indicazione esplicita di dove e come si intendesse intervenire, per perseguire esiti corretti dal punto di vista tecnico e metodologico.