Search results for "Correlation"

CLUSTERING INCOMPLETE SPECTRAL DATA WITH ROBUST METHODS

2018

Abstract. Missing value imputation is a common approach for preprocessing incomplete data sets. In case of data clustering, imputation methods may cause unexpected bias because they may change the underlying structure of the data. In order to avoid prior imputation of missing values the computational operations must be projected on the available data values. In this paper, we apply a robust nan-K-spatmed algorithm to the clustering problem on hyperspectral image data. Robust statistics, such as multivariate medians, are more insensitive to outliers than classical statistics relying on the Gaussian assumptions. They are, however, computationally more intractable due to the lack of closed-for…

THE CORRELATION BETWEEN FISCAL REVENUES OF ROMANIA AND GROSS DOMESTIC PRODUCT IN THE LAST 12 YEARS

2018

The aim of this paper is to study and analyze the evolution of the Romanian fiscal pressure between 2006 and 2017, from a statistical point of view, and the main purpose is to highlight the correlation between fiscal revenues of Romania and gross domestic product. The first part of the paper is based on a comparative research into the level of taxation at the level of direct, indirect taxes and social contributions. This study seeks to highlight the impact of the Romanian fiscal pressure on the economy. The second part of the article seeks to see the correlation between fiscal revenues and gross domestic product (GDP), especially the impact of fiscal revenues on the growth or decline of GDP…

Generation of Natural Runoff Monthly Series at Ungauged Sites Using a Regional Regressive Model

2016

Many hydrologic applications require reliable estimates of runoff in river basins to face the widespread lack of data, both in time and in space. A regional method for the reconstruction of monthly runoff series is here developed and applied to Sicily (Italy). A simple modeling structure is adopted, consisting of a regression-based rainfall–runoff model with four model parameters, calibrated through a two-step procedure. Monthly runoff estimates are based on precipitation, temperature, and exploiting the autocorrelation with runoff at the previous month. Model parameters are assessed by specific regional equations as a function of easily measurable physical and climate basin descriptors. Th…

Jet fragmentation transverse momentum from h-h correlations in pp and p-Pb collisions

2017

Evolutionary constraints of warning signals : a genetic trade-off between the efficacy of larval and adult warning coloration can maintain variation …

2016

To predict evolutionary responses of warning signals under selection, we need to determine the inheritance pattern of the signals, and how they are genetically correlated with other traits contributing to fitness. Furthermore, protective coloration often undergoes remarkable changes within an individual's lifecycle, requiring us to quantify the genetic constraints of adaptive coloration across all the relevant life stages. Based on a 12 generation pedigree with > 11,000 individuals of the wood tiger moth (Arctia plantaginis), we show that high primary defense as a larva (large warning signal) results in weaker defenses as adult (less efficient warning color), due to the negative genetic cor…

The charm-quark contribution to light-by-light scattering in the muon (−2) from lattice QCD

2022

We compute the hadronic light-by-light scattering contribution to the muon $g-2$ from the charm quark using lattice QCD. The calculation is performed on ensembles generated with dynamical $(u,d,s)$ quarks at the SU(3)$_{\rm f}$ symmetric point with degenerate pion and kaon masses of around 415 MeV. It includes the connected charm contribution, as well as the leading disconnected Wick contraction, involving the correlation between a charm and a light-quark loop. Cutoff effects turn out to be sizeable, which leads us to use lighter-than-physical charm masses, to employ a broad range of lattice spacings reaching down to 0.039 fm and to perform a combined charm-mass and continuum extrapolation.…

The impact of financial crises on co-movements between commodity futures and equity prices : evidence from crude oil and gold markets

2017

Omaisuusluokkien välisillä korrelaatioilla on tärkeä rooli sijoitussalkun hajautusta ajatellen. Omaisuuslajien suojauksen kannalta erityisen tärkeää on tutkia, miten eri omaisuusluokat korreloivat kriisiperiodien aikana. Tässä Pro-Gradu -tutkielmassa tarkastellaan osakemarkkinakriisien vaikutusta hyödykefutuurien ja osakemarkkinatuottojen välisiin korrelaatioihin USA:n markkinoilla erityisesti raakaöljyn ja kullan osalta. Korrelaatioiden mallintamisessa hyödynnetään Cappiellon, Englen ja Sheppardin vuonna 2006 ehdottamaa yleistettyä diagonaalimuotoista DCC GARCH -mallia. Tutkimuksessa verrataan ehdollisten korrelaatioiden kehitystä erikseen USA:n osakemarkkinoiden yleisindeksin ja energiase…

Identifying Oscillatory Hyperconnectivity and Hypoconnectivity Networks in Major Depression Using Coupled Tensor Decomposition

2021

AbstractPrevious researches demonstrate that major depression disorder (MDD) is associated with widespread network dysconnectivity, and the dynamics of functional connectivity networks are important to delineate the neural mechanisms of MDD. Cortical electroencephalography (EEG) oscillations act as coordinators to connect different brain regions, and various assemblies of oscillations can form different networks to support different cognitive tasks. Studies have demonstrated that the dysconnectivity of EEG oscillatory networks is related with MDD. In this study, we investigated the oscillatory hyperconnectivity and hypoconnectivity networks in MDD under a naturalistic and continuous stimuli…

EFFECTIVENESS OF BASALT FIBRE-REINFORCED CEMENTITIOUS SYSTEMS IN CONFINING MASONRY MEMBERS: AN EXPERIMENTAL INVESTIGATION

2020

The use of composites based on fibre-reinforced polymers (FRPs) to strengthen masonry columns has become a common practice in the last decades. FRPs, however, exhibit some shortcomings when applied to masonry substrates, due to the organic nature of their matrix. For this reason, increasing attention is paid today to composites based on fibre-reinforced cementitious matrices (FRCMs), in which the polymeric matrix is replaced with an inorganic matrix (such as cementitious mortars). Cementitious matrices guarantee higher breathability and compatibility with the substrate, less sensitivity to debonding at the interfaces, and higher resistance to fire and high temperatures. Moreover, due to the…

A meta-analysis of the relation between RAN and mathematics.

2017

Several studies have shown that rapid automatized naming (RAN) is a significant predictor of mathematics, but the nature of their relationship remains elusive. Thus, the purpose of this meta-analysis was to estimate the size of their relationship and determine the conditions under which they correlate. We used a random-effects model analysis of data from 38 studies (33 unique samples, 151 correlations, 7,135 participants) to examine the size of the RAN–mathematics relationship and the role of different moderators (i.e., math measure and variable, type of RAN task, math age, study design, and sample characteristics). The results showed a significant correlation between RAN and mathematics (r…