2,652 research outputs found
A Neural Network Model for Forecasting Photovoltaic Deployment in Italy
The photovoltaic (PV) industry in Italy has already crossed the threshold of 1 GW of installed capacity. Currently there are approximately 70,000 certified facilities in operation for a power generation of 1,300 GWh/year. With these figures, Italy has become the second country in Europe for PV installed power after Germany. The energy produced would be sufficient to meet the power needs of approximately 1,200,000 people. This leads to some questions: Will this technology continue to grow exponentially even after the recent reduction in rates by the Energy Bill? Will the number of installed PV facilities still grow even with less public support and (probably) a reduction in the technology purchase price? The purpose of this paper is therefore to develop a conceptual model to make a prediction of the PV installed power in Italy through the use of âsupervisedâ artificial neural networks. This model is also applied to the analysis of the spread of this technology in some other European countries
Energy Saving in Link Stability Routing Protocol
Because the CPU is a very expensive resource in mobile ad hoc networks (MANETs), it is very important to consider the overhead introduced in a routing protocol. Many theories have been hypothesized with the aim of minimizing it. But how much is the energy consumption from a network nodeâs battery induced by the routing protocol overhead? In a previous work, we dealt with a routing protocol based on link stability (link duration observed in a time interval). In this work, we attempt to hypothesize a model for conserving the battery energy consumed by nodes in a MANET adopting the link stability routing protocol
Numerical method for hypersingular integrals of highly oscillatory functions on the positive semiaxis
This paper deals with a quadrature rule for the numerical evaluation of hypersingular integrals of highly oscillatory functions on the positive semiaxis. The rule is of product type and consists in approximating the density function f by a truncated interpolation process based on the zeros of generalized Laguerre polynomials and an additional point. We prove the stability and the convergence of the rule, giving error estimates for functions belonging to weighted Sobolev spaces equipped with uniform norm. We also show how the proposed rule can be used for the numerical solution of hypersingular integral equations. Numerical tests which confirm the theoretical estimates and comparisons with other existing quadrature rules are presented
On the stability of a modified Nyström method for Mellin convolution equations in weighted spaces
This paper deals with the numerical solution of second kind integral equations with fixed singularities of Mellin convolution type. The main difficulty in solving such equations is the proof of the stability of the chosen numerical method, being the noncompactness of the Mellin integral operator the chief theoretical barrier. Here, we propose a Nyström method suitably modified in order to achieve the theoretical stability under proper assumptions on the Mellin kernel. We also provide an error estimate in weighted uniform norm and prove the well-conditioning of the involved linear systems. Some numerical tests which confirm the efficiency of the method are shown
A NUMERICAL METHOD FOR SOLVING SYSTEMS OF HYPERSINGULAR INTEGRO-DIFFERENTIAL EQUATIONS
This paper is concerned with a collocation-quadrature method for solving systems of Prandtl's integro-differential equations based on de la Vallee Poussin filtered interpolation at Chebyshev nodes. We prove stability and convergence in Holder-Zygmund spaces of locally continuous functions. Some numerical tests are presented to examine the method's efficacy
Semilinear problems for the fractional laplacian with a singular nonlinearity
The aim of this paper is to study the solvability of the problem (-Î)s u = F(x,u) := λ f(x)/uÎł + Mup in Ï u > 0 in Ï, u = 0 in RN \ Ï, where Ω is a bounded smooth domain of RN, N > 2s, M Δ {0, 1}, 0 0, λ > 0, p > 1 and f is a nonnegative function. We distinguish two cases: - For M = 0, we prove the existence of a solution for every Îł > 0 and λ > 0. A1 - For M = 1, we consider f ⥠1 and we find a threshold ⧠such that there exists a solution for every 0 â§Work partially supported by project MTM2013-40846-P MINECO. The third author is also supported for the grant BES-2011-044216 associated to MTM2010-1812
GALNT2 as a novel modulator of adipogenesis and adipocyte insulin signaling
Background/objectives: A better understanding of adipose tissue biology is crucial to tackle insulin resistance and eventually coronary heart disease and diabetes, leading causes of morbidity and mortality worldwide. GALNT2, a GalNAc-transferase, positively modulates insulin signaling in human liver cells by down-regulating ENPP1, an insulin signaling inhibitor. GALNT2 expression is increased in adipose tissue of obese as compared to that of non-obese individuals. Whether this association is secondary to a GALNT2-insulin sensitizing effect exerted also in adipocytes is unknown. We then investigated in mouse 3T3-L1 adipocytes the GALNT2 effect on adipogenesis, insulin signaling and expression levels of both Enpp1 and 72 adipogenesis-related genes. Methods: Stable over-expressing GALNT2 and GFP preadipocytes (T 0 ) were generated. Adipogenesis was induced with (R+) or without (Râ) rosiglitazone and investigated after 15 days (T 15 ). Lipid accumulation (by Oil Red-O staining) and intracellular triglycerides (by fluorimetric assay) were measured. Lipid droplets (LD) measures were analyzed at confocal microscope. Gene expression was assessed by RT-PCR and insulin-induced insulin receptor (IR), IRS1, JNK and AKT phosphorylation by Western blot. Results: Lipid accumulation, triglycerides and LD measures progressively increased from T 0 to T 15 R- and furthermore to T 15 R+. Such increases were significantly higher in GALNT2 than in GFP cells so that, as compared to T 15 R+GFP, T 15 R- GALNT2 cells showed similar (intracellular lipid and triglycerides accumulation) or even higher (LD measures, p < 0.01) values. In GALNT2 preadipocytes, insulin-induced IR, IRS1 and AKT activation was higher than that in GFP cells. GALNT2 effect was totally abolished during adipocyte maturation and completely reversed at late stage maturation. Such GALNT2 effect trajectory was paralleled by coordinated changes in the expression of Enpp1 and adipocyte-maturation key genes. Conclusions: GALNT2 is a novel modulator of adipogenesis and related cellular phenotypes, thus becoming a potential target for tackling the obesity epidemics and its devastating sequelae
MatLab Toolbox for the numerical solution of linear Volterra integral equations arising in metastatic tumor growth models
This paper introduces VIE Toolbox composed by fourteen MatLab functions used for the numerical resolution of Volterra Integral Equations (VIEs) of the second kind on infinite intervals. An application to metastatic tumor growth models is also considered, assuming five different tumor growth laws, e.g. exponential, power-law, Gompertz, generalized logistic and von Bertalanffy-West laws, for lung and breast tumors data
Special Issue on functional analysis, approximation theory and numerical analysis (FAATNA20>22)
Determinants of health sector efficiency: evidence from a two-step analysis on 30 OECD countries
This study aims to assess the efficiency of expenditure on health in 30 OECD countries over the period 2005-2015 by
regressing Data Envelopment Analysis (DEA) output efficiency scores on discretionary and non-discretionary
variables, with a two-stage DEA/Tobit and bootstrap procedure. We show that health inefficiency in OECD countries
is related to per capita GDP, vaccine coverage and tobacco consumption, also controlling for geographical and
institutional variables (i.e., bureaucratic red tape and weather temperature)
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