Search results for "Chains"
showing 10 items of 257 documents
Levy targeting and the principle of detailed balance
2011
We investigate confining mechanisms for Lévy flights under premises of the principle of detailed balance. In this case, the master equation of the jump-type process admits a transformation to the Lévy-Schrödinger semigroup dynamics akin to a mapping of the Fokker-Planck equation into the generalized diffusion equation. This sets a correspondence between above two stochastic dynamical systems, within which we address a (stochastic) targeting problem for an arbitrary stability index μ ε (0,2) of symmetric Lévy drivers. Namely, given a probability density function, specify the semigroup potential, and thence the jump-type dynamics for which this PDF is actually a long-time asymptotic (target) …
The pianigiani-yorke measure for topological markov chains
1997
We prove the existence of a Pianigiani-Yorke measure for a Markovian factor of a topological Markov chain. This measure induces a Gibbs measure in the limit set. The proof uses the contraction properties of the Ruelle-Perron-Frobenius operator.
Context Trees, Variable Length Markov Chains and Dynamical Sources
2012
Infinite random sequences of letters can be viewed as stochastic chains or as strings produced by a source, in the sense of information theory. The relationship between Variable Length Markov Chains (VLMC) and probabilistic dynamical sources is studied. We establish a probabilistic frame for context trees and VLMC and we prove that any VLMC is a dynamical source for which we explicitly build the mapping. On two examples, the "comb" and the "bamboo blossom", we find a necessary and sufficient condition for the existence and the uniqueness of a stationary probability measure for the VLMC. These two examples are detailed in order to provide the associated Dirichlet series as well as the genera…
QUANTITATIVE CONVERGENCE RATES FOR SUBGEOMETRIC MARKOV CHAINS
2015
We provide explicit expressions for the constants involved in the characterisation of ergodicity of subgeometric Markov chains. The constants are determined in terms of those appearing in the assumed drift and one-step minorisation conditions. The results are fundamental for the study of some algorithms where uniform bounds for these constants are needed for a family of Markov kernels. Our results accommodate also some classes of inhomogeneous chains.
Role of alternative food networks in Sicilian farms
2014
Today the short supply chain can be carried out through several typologies which are called as alternative food networks (AFNs). In fact, according to some studies, it is an 'alternative' response to the dominant agro-food system, which offers the possibility to produce food products through supply chains that are opposed to long, complex and rationally organised industrial chains. In the last years many European farmers adopted short supply chain to commercialise their agro-food products and Italy is one of the EU members in which AFNs are developed, thanks to its numerous typical an local products. The aim of this paper has been to analyse the role that AFNs play in Sicilian farms and how…
A study on forecasting electricity production and consumption in smart cities and factories
2019
Abstract The electrical power sector must undergo a thorough metamorphosis to achieve the ambitious targets in greenhouse gas reduction set forth in the Paris Agreement of 2015. Reducing uncertainty about demand and, in case of renewable electricity generation, supply is important for the determination of spot electricity prices. In this work we propose and evaluate a context-based technique to anticipate the electricity production and consumption in buildings. We focus on a household with photovoltaics and energy storage system. We analyze the efficiency of Markov chains, stride predictors and also their combination into a hybrid predictor in modelling the evolution of electricity producti…
Comparison of different uncertainty techniques in urban stormwater quantity and quality modelling
2011
Abstract Urban drainage models are important tools used by both practitioners and scientists in the field of stormwater management. These models are often conceptual and usually require calibration using local datasets. The quantification of the uncertainty associated with the models is a must, although it is rarely practiced. The International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, has been working on the development of a framework for defining and assessing uncertainties in the field of urban drainage modelling. A part of that work is the assessment and comparison of different techniques generally used in the uncertainty assessm…
Understanding flow experience from users’ requirements
2015
This paper argues that the concept of flow can be useful in gaining a better understanding of information system users’ flow experience. This paper applies this concept in the requirements development phase of an Internet protocol television e-learning service development project. The findings show that flow experience can be visualised and measured, and that there are differences in how users see and perceive different features. Some features are driven by more experiential needs, whereas others are driven by more task-oriented goals. The findings indicate that the users’ perceived flow experiences can already be measured during the early phases of information systems IS development projec…
The Role of Partnerships in the Development of the Short Chains of Organic Honey Distribution
2020
Abstract The bees were declared the most important living beings on the planet. They act as natural indicators of the state of the environment, protect and maintain ecosystems and contribute to genetic and biotic diversity. Due to its socio-economic and scientific role, beekeeping is an activity that contributes to the development of the rural area. In the analysis we have chosen Hunedoara County, considering its national position and prospects for the development of organic beekeeping. The elaboration of the PESTEL analysis ensures a long-term perspective of the apiculture strategy in Hunedoara County. In order to dispose of bee products (honey, organic honey, pollen, propolis, etc.) in op…
From an epoxide monomer toolkit to functional PEG copolymers with adjustable LCST behavior.
2011
The lower critical solution temperature (LCST) behavior of novel poly(ethylene glycol) (PEG)-based copolymers bearing multiple functional groups, obtained by anionic ring-opening (co)polymerization (AROP), has been investigated. Variable comonomer ratios of ethylene oxide (EO) and the corresponding oxiranes isopropylidene glyceryl glycidyl ether (IGG), ethoxyl vinyl glycidyl ether (EVGE), allyl glycidyl ether (AGE), or N,N-dibenzyl amino glycidyl (DBAG), particularly designed to implement functional groups at the PEG backbone, were found to influence the LCST behavior. Sharp transitions from translucent to opaque solutions, comparable to other well-established stimuli-responsive polymers, w…