Search results for " correlation"
showing 10 items of 1380 documents
Molecular topology and chromatographic retention parameters for benzodiazepines
1992
Abstract The relationship between gas-liquid chromatographic (GLC) retention properties and R F values in thin-layer chromatography (TLC) with molecular connectivity indices, m X t , was investigated for a series of benzodiazepines using multiple correlation coefficients, standard errors of estimate, F -Snedecor function values and Student's t -test as the criteria for best equation selection. Regression analyses show that the molecular connectivity model predicts the retention properties in GLC with the polar stationary phase OV-17 at 280°C and the R F values in TLC with the stationary phase silica gel. However, zero- or second-order connectivity indices alone are not sufficient; higher-or…
A Coherent derivation of an average ion model including the evolution of correlations between different shells
2013
We propose in this short note a method enabling to write in a systematic way a set of refined equations for average ion models in which correlations between populations are taken into account, starting from a microscopic model for the evolution of the electronic configura- tion probabilities. Numerical simulations illustrating the improvements with respect to standard average ion models are presented at the end of the paper.
N-Isopropylacrylamide andN-Isopropylmethacryl-amide: Cloud Points of Mixtures and Copolymers
2001
The cloud point curve of aqueous solutions of poly(N-isopropylacrylamide), poly(N-isopropylmethacrylamide) and their statistical copolymers were determined turbidimetrically. All the Systems demix upon heating at the cloud point temperature and mix reversibly upon cooling. The cloud points are independent of the total concentration of the solutions (dilute range) and of the sample thickness. Mixtures of the homopolymers poly(N-isopropylacrylamide) and poly(N-isopropylmethacrylamide) in water (ternary systems) exhibit two cloud points, which are nearly the same as the cloud points of the two binary systems homopolymer/water. A quantitative correlation was found between the cloud point temper…
Distance Functions, Clustering Algorithms and Microarray Data Analysis
2010
Distance functions are a fundamental ingredient of classification and clustering procedures, and this holds true also in the particular case of microarray data. In the general data mining and classification literature, functions such as Euclidean distance or Pearson correlation have gained their status of de facto standards thanks to a considerable amount of experimental validation. For microarray data, the issue of which distance function works best has been investigated, but no final conclusion has been reached. The aim of this extended abstract is to shed further light on that issue. Indeed, we present an experimental study, involving several distances, assessing (a) their intrinsic sepa…
Using Aerial Platforms in Predicting Water Quality Parameters from Hyperspectral Imaging Data with Deep Neural Networks
2020
In near future it is assumable that automated unmanned aerial platforms are coming more common. There are visions that transportation of different goods would be done with large planes, which can handle over 1000 kg payloads. While these planes are used for transportation they could similarly be used for remote sensing applications by adding sensors to the planes. Hyperspectral imagers are one this kind of sensor types. There is need for the efficient methods to interpret hyperspectral data to the wanted water quality parameters. In this work we survey the performance of neural networks in the prediction of water quality parameters from remotely sensed hyperspectral data in freshwater basin…
S_Kernel: A New Symmetry Measure
2005
Symmetry is an important feature in vision. Several detectors or transforms have been proposed. In this paper we concentrate on a measure of symmetry. Given a transform S, the kernel SK of a pattern is defined as the maximal included symmetric sub-set of this pattern. It is easily proven that, in any direction, the optimal axis corresponds to the maximal correlation of a pattern with its flipped version. For the measure we compute a modified difference between respective surfaces of a pattern and its kernel. That founds an efficient algorithm to attention focusing on symmetric patterns.
Spectral density of the correlation matrix of factor models: a random matrix theory approach.
2005
We studied the eigenvalue spectral density of the correlation matrix of factor models of multivariate time series. By making use of the random matrix theory, we analytically quantified the effect of statistical uncertainty on the spectral density due to the finiteness of the sample. We considered a broad range of models, ranging from one-factor models to hierarchical multifactor models.
Co-jumps and Markov Counting Systems in Random Environments
2020
Motivated by the analysis of multi-strain infectious disease data, we provide closed-form transition rates for continuous-time Markov chains that arise from subjecting Markov counting systems to correlated environmental noises. Noise correlation induces co-jumps or counts that occur simultaneously in several counting processes. Such co-jumps are necessary and sufficient for infinitesimal correlation between counting processes of the system. We analyzed such infinitesimal correlation for a specific infectious disease model by randomizing time of Kolmogorov’s Backward system of differential equations based on appropriate stochastic integrals.
V11. Functional hierarchy within an overall network for visual motion processing and ocular-motor control at rest
2015
Introduction Visual motion processing on one hand and ocular motor functions on the other are rarely studied together in vivo in humans. The interrelation of these functional networks is rather unclear, even though their functional dependence seems obvious. In several fMRI studies the essential nodes of both networks could be localized using voluntary optokinetic ('look') nystagmus (OKN) in the horizontal plane incorporating visual motion tracking (Dieterich et al., 2009). Here, functional connectivity (FC) between these nodes representing both networks was studies using resting-state FC. Methods Resting-state fMRI data of 200 healthy adults (age 44.1±17.9; 79 male) were included in the cro…
Threats and attitudes toward Russian-speaking immigrants: a comparative study between younger and older Finns
2014
Using integrated threat theory as a theoretical lens to detect negative attitudes toward minority groups, this study compares and contrasts the perceptions and attitudes of older and younger Finns toward Russian-speaking minorities in Finland. A sample of high school students between 16 and 20 years of age represented the younger generation, while individuals over 65 years of age represented the older generation. The total sample was 242. Results indicated that there is a positive correlation between threat perception and prejudice. Results revealed that both groups have prejudices against Russian speakers and that these prejudices are related to the perception of realistic threat and negat…