Search results for "Correlation"
showing 10 items of 2282 documents
On utilizing dependence-based information to enhance micro-aggregation for secure statistical databases
2011
Published version of an article in the journal: Pattern Analysis and Applications. Also available from the publisher at: http://dx.doi.org/10.1007/s10044-011-0199-9 We consider the micro-aggregation problem which involves partitioning a set of individual records in a micro-data file into a number of mutually exclusive and exhaustive groups. This problem, which seeks for the best partition of the micro-data file, is known to be NP-hard, and has been tackled using many heuristic solutions. In this paper, we would like to demonstrate that in the process of developing micro-aggregation techniques (MATs), it is expedient to incorporate information about the dependence between the random variable…
The Stabilizing Role of Government Size
2007
This paper presents an analysis of how alternative models of the business cycle can replicate the stylized fact that large governments are associated with less volatile economies. Our analysis shows that adding nominal rigidities and costs of capital adjustment to an otherwise standard RBC model can generate a negative correlation between government size and the volatility of output. However, in the model, we find that the stabilizing effect is only due to a composition effect and it is not present when we look at the volatility of private output. Given that empirically we also observe a negative correlation between government size and the volatility of consumption, we modify the model by i…
Convection and thermodiffusion of colloidal gold tracers by laser light scattering
1999
In a dynamic light scattering experiment, we have investigated the time intensity correlation function and the profile of the transmitted laser beam for organic dispersions of light absorbing colloidal particles containing tiny gold clusters. The correlation functions have been found to show a superposition of an exponential decay, corresponding to Brownian motion of the tracers, and well-defined oscillations. These oscillations are caused by convection due to local heating of the sample by the incident laser beam, which has been confirmed independently via measurements of the local temperature within the sample. It will be shown how the particle convection velocity, which is the order of 1…
Is the Kidscreen-27 a valid measure of health-related quality of life in 10-year-old Norwegian children?
2015
The aim of this study was to investigate the reliability and validity of the Norwegian Kidscreen-27 questionnaire, a measure of generic health-related quality of life, in 10 year-old children. The Kidscreen-27 consists of five domains and was validated in a sample of 56 school children (29 boys). The children completed the questionnaire at three different time points during two consecutive school days. For convergent validity, the study was powered to detect a statistically significant correlation coefficient of 0.4. Cronbach's alpha values ranged from 0.73 to 0.83. Floor effects were all zero and ceiling effects ranged from 1.7% to 23.7%. Intraclass correlation values over time ranged from…
Mammographic images segmentation based on chaotic map clustering algorithm
2013
Background: This work investigates the applicability of a novel clustering approach to the segmentation of mammographic digital images. The chaotic map clustering algorithm is used to group together similar subsets of image pixels resulting in a medically meaningful partition of the mammography. Methods: The image is divided into pixels subsets characterized by a set of conveniently chosen features and each of the corresponding points in the feature space is associated to a map. A mutual coupling strength between the maps depending on the associated distance between feature space points is subsequently introduced. On the system of maps, the simulated evolution through chaotic dynamics leads…
The Relation Between Maternal Locus of Control And Coping Styles of Pediatric Leukemia Patients During Treatment
2020
The present study focuses on the relation between coping strategies of children with leukemia during treatment and locus of control of their mothers. In particular, the study aims to determine whether maternal locus of control can influence sick children’s coping styles, and if this relation can be used to predict maladjustments. The study analyzed a cohort of 60 pediatric leukemia patients undergoing treatment and a group formed by their mothers. The participants were recruited from two Pediatric Onco- Hematology Units in Italy. The Child Behavioral Style Scale (CBSS) was used to assess children’s coping strategies, whereas the Parental Health Locus of Control Scale (PHLCS) was employed to…
Seamless downscaling of the ESA CCI soil moisture data at the daily scale with MODIS land products
2021
Abstract Spatial downscaling has recently become a crucial process in the regional application of coarse-resolution passive microwave surface soil moisture (SSM) products. Extensive gaps in auxiliary optical/thermal infrared observation data (mainly caused by cloud cover) and gaps in coarse-resolution passive microwave SSM data lead to spatiotemporal discontinuity in downscaled SSM maps, thereby limiting their applications. An improved downscaling method for the 25-km European Space Agency (ESA) Climate Change Initiative (CCI) SSM product was proposed to obtain daily seamless downscaled SSM series at a 1-km scale. The Moderate Resolution Imaging Spectroradiometer (MODIS) Terra daily land su…
High performance hardware correlation coefficient assessment using programmable logic for ECG signals
2003
Abstract Correlation coefficient is frequently used to obtain cardiac rhythm by peak estimation and appreciate differences in the signal compared to a pattern. This work focuses on the description of a real-time correlation assessment procedure. Applied to electrocardiogram (ECG) signals, a new correlation value is obtained every new sample and pulse detection information is provided. The ECG pattern is internally stored and can be changed when desired. This procedure is useful in Systems on Chip implementation and can be applied to design compact ECG monitoring systems consisting on a system on chip where programmable logic offloads the main processor. A Xilinx FPGA device has been used fo…
A systematic comparison of kinetic modelling methods generating parametric maps for [11C]-(R)-PK11195
2006
[(11)C]-(R)-PK11195 is presently the most widely used radiotracer for the monitoring of microglia activity in the central nervous system (CNS). Microglia, the resident immune cells of the brain, play a critical role in acute and chronic diseases of the central nervous system and in host defence against neoplasia. The purpose of this investigation was to evaluate the reliability and sensitivity of five kinetic modelling methods for the formation of parametric maps from dynamic [(11)C]-(R)-PK11195 studies. The methods we tested were the simplified reference tissue model (SRTM), basis pursuit, a simple target-to-reference ratio, the Logan plot and a wavelet based Logan plot. For the reliabilit…
Information and hierarchical structure in financial markets
1999
I investigate the information content present in the time series of stock prices of a portfolio of stocks traded in a financial market. By investigating the correlation coefficient between pairs of stocks I provide a working definition of a generalized distance between the stocks of the portfolio. This generalized distance is used to obtain an ultrametric distance matrix between the stocks. The ultrametric structure of the portfolio investigated has associated a taxonomy which is meaningful from an economic point of view.