Search results for " Brown"
showing 10 items of 136 documents
Coalescing directed random walks on the backbone of a 1 +1-dimensional oriented percolation cluster converge to the Brownian web
2018
We consider the backbone of the infinite cluster generated by supercritical oriented site percolation in dimension 1 +1. A directed random walk on this backbone can be seen as an "ancestral line" of an individual sampled in the stationary discrete-time contact process. Such ancestral lineages were investigated in [BCDG13] where a central limit theorem for a single walker was proved. Here, we consider infinitely many coalescing walkers on the same backbone starting at each space-time point. We show that, after diffusive rescaling, the collection of paths converges in distribution to the Brownian web. Hence, we prove convergence to the Brownian web for a particular system of coalescing random…
Enhancing Urban Brownfield Regeneration to Pursue Sustainable Community Outcomes through Dynamic Performance Governance
2019
This paper discusses the case of Puerto Madero (Buenos Aires, Argentina) to illustrate how the “Dynamic Performance Governance” framework is able to support policy networks to pursue sustainable community outcomes in urban brownfield regeneration. The case is an example of successful implementation of urban renewal carried out through a significant involvement of the private sector. It portrays a “financially-driven” governance mode which entails balancing the advantage of cash flow reinvestment for public services and infrastructure capacity development, with potential shortcomings in terms of social inclusion. Findings reveal two main trade-offs associated with policy design and implement…
A Novel Non-Stationary Channel Model Utilizing Brownian Random Paths
2014
This paper proposes a non-stationary channel model in which real-time dynamics of the mobile station (MS) are taken into account. We utilize Brownian motion (BM) processes to model targeted and non-targeted dynamics of the MS. The proposed trajectory model consists of both drift and random components to capture both targeted and non-targeted motions of the MS. The Brownian trajectory model is then employed to provide a non-stationary channel model, in which the scattering effects of the propagation area are modelled by a non-centred one-ring geometric scattering model. The starting point of the motion is a fixed point in the propagation environment, whereas its terminating point is a random…
Dynamics of a quantum particle interacting with a thermal bath and subject to an oscillating asymmetric bistable potential
2012
Exploiting the approach of the Feynman-Vernon influence functional [1] within the framework of the discrete variable representation (DVR) [2], we consider a quantum particle described by the Caldeira-Leggett model [3]. The particle, “moving” in an asymmetric bistable potential and subject to a periodical driving, interacts with a thermal bath of harmonic oscillators. In this conditions we study the dynamics of the particle by analyzing the time evolution of the populations in the DVR. Specifically we focalize on the position eigenstate located in the shallower well, i.e. metastable state, finding a non-monotonic behaviour of the corresponding population as a function of the frequency. Moreo…
Dynamics of a Driven Dissipative Quantum System
2013
We investigate the dynamics of a driven multilevel system, consisting of a particle in an asymmetric bistable potential, strongly interacting with a thermal bath according to the Caldeira-Leggett model. The populations in the discrete (position) variable representation (DVR), are obtained as solution of a Markovian approximated master equation, which is derived from a discretized path integral approach based on the Feynman-Vernon influence functional. By varying the environmental parameters (temperature and coupling strength) as well as the driving frequency and amplitude, we study the transient dynamics and stationary configuration of the system. In particular, we analyze the population of…
Transient Dynamics of a Driven Quantum Bistable System
2013
We study the transient dynamics and the asymptotic behaviour of a multilevel system in the strong dissipation regime. The system is modeled as a periodically driven quantum particle in an asymmetric double well potential, interacting with the bosonic heat bath of the Caldeira-Leggett model. The analytical approach used is non- perturbative in the particle-bath coupling and is based on a space-discretized path integral expression for the particle’s reduced density matrix. By a suitable approximation on the Feynman-Vernon influence functional a Markov-approximated master equation is obtained for the populations in the Discrete Variable Representation (DVR).
Energie rinnovabili e trasformazioni territoriali: il caso del fotovoltaico in Sicilia
2021
La presente comunicazione intende trattare il tema delle trasformazioni territoriali sono avvenute negli ultimi due decenni in Sicilia, in seguito alla costruzione di centinaia di impianti fotovoltaici di piccole, medie e grandi dimensioni. Tali impianti sono stati costruiti causando spesso profondi mutamenti paesaggio, con trasformazioni territoriali che non hanno tenuto conto delle caratteristiche di produttività dei suoli, della vicinanza di aree protette e siti della Rete Natura 2000 e soprattutto senza il reale coinvolgimento delle comunità locali che spesso hanno subito passivamente tali trasformazioni. Gli strumenti di pianificazione territoriale, quali il Piano Paesistico Regionale,…
Efficient or Fractal Market Hypothesis? A Stock Indexes Modelling Using Geometric Brownian Motion and Geometric Fractional Brownian Motion
2021
In this article, we propose a test of the dynamics of stock market indexes typical of the US and EU capital markets in order to determine which of the two fundamental hypotheses, efficient market hypothesis (EMH) or fractal market hypothesis (FMH), best describes market behavior. The article’s major goal is to show how to appropriately model return distributions for financial market indexes, specifically which geometric Brownian motion (GBM) and geometric fractional Brownian motion (GFBM) dynamic equations best define the evolution of the S&P 500 and Stoxx Europe 600 stock indexes. Daily stock index data were acquired from the Thomson Reuters Eikon database during a ten-year period, fro…
Sustainable Regeneration of Brownfields
2016
Our cities are really rich of building ensembles now deserted which were, in the recent past, sources of job and productivity for the community. They are generally inside the urban fabric or in the suburbs and they are often not particularly taken into consideration because they haven’t architectonic characteristics which could justify a restoration. Due to their big extension, the planning approach turns to be diffucult. Besides, these areas, if adequately restored, could become an important economic and cultural resource and a possibility of experimentation of new sustainable technologies. All this heritage requires a planning approach based on conservation and valorization of all the cul…
EFFECT OF PASSIVE ATMOSPHERE AND CHEMICAL TREATMENT ON FRESH CUT OF WHITE-FLESH PEACH CULTIVAR 'SETTEMBRINA DI BIVONA'
2015
Peach germplasm in Italy includes white- and yellow-flesh peaches, all of them characterized by a persistent aroma and an excellent flavor. However, their behavior, in terms of postharvest maintenance and suitability for minimal processing, has never been investigated. The aim of this study was to investigate the effects of passive atmosphere and chemical treatment, with 2% ascorbic acid and 1% calcium lactate, in order to prevent fruit browning and to maintain the quality of fresh cut slices of the white-flesh peach cultivar ‘Settembrina di Bivona’. To achieve a passive atmosphere condition, approximately 150 g of peach fruit slices were placed in rigid bi-oriented polystyrene bags and sto…