Search results for "NETWORKING"
showing 10 items of 1776 documents
Atmospheric Turbulence Effects Removal on Infrared Sequences Degraded by Local Isoplanatism
2007
When observing an object horizontally at a long distance, degradations due to atmospheric turbulence often occur. Different methods have already been tested to get rid of this kind of degradation, especially on infrared sequences. It has been shown that the Wiener filter applied locally on each frame of a sequence allows to obtain good results in terms of edges, while the regularization by the Laplacian operator applied in the same way provides good results in terms of noise removal in uniform areas. In this article, we present hybrid methods which take advantages of both Wiener filter and Laplacian regularization.
Deflation-Based FastICA With Adaptive Choices of Nonlinearities
2014
Deflation-based FastICA is a popular method for independent component analysis. In the standard deflation-base d approach the row vectors of the unmixing matrix are extracted one after another always using the same nonlinearities. In prac- tice the user has to choose the nonlinearities and the efficiency and robustness of the estimation procedure then strongly depends on this choice as well as on the order in which the components are extracted. In this paper we propose a novel adaptive two- stage deflation-based FastICA algorithm that (i) allows one to use different nonlinearities for different components and (ii) optimizes the order in which the components are extracted. Based on a consist…
OLS Identification of network topologies
2011
Abstract In many applications, it is important to derive information about the topology and the internal connections of more dynamical systems interacting together. Examples can be found in fields as diverse as Economics, Neuroscience and Biochemistry. The paper deals with the problem of deriving a descriptive model of a network, collecting the node outputs as time series with no use of a priori insight on the topology. We cast the problem as the optimization of a cost function where a set of parameters are used to operate a trade-off between accuracy and complexity in the final model. The problem of reducing the complexity is addressed by fixing a certain degree of sparsity and finding the…
Accelerating Application Migration in HPC
2016
It is predicted that the number of cores per node will rapidly increase with the upcoming era of exascale supercomputers. As a result, multiple applications will have to share one node and compete for the (often scarce) resources available on this node. Furthermore, the growing number of hardware components causes a decrease in the mean time between failures. Application migration between nodes has been proposed as a tool to mitigate these two problems: Bottlenecks due to resource sharing can be addressed by load balancing schemes which migrate applications; and hardware errors can often be tolerated by the system if faulty nodes are detected and processes are migrated ahead of time.
Field Measurements and Parameter Calibrations of Propagation Model for Digital Audio Broadcasting in Norway
2018
During 2017, digital audio broadcasting (DAB) replaces frequency modulation (FM) broadcasting and becomes the only technology for national terrestrial audio broadcasting services in Norway. As Norway is the first country that replaces FM completely with DAB, it is of great importance to measure the signal strength of such a technology in massive deployments and to tune a simulation model as a reference for future studies. Therefore, field measurements of received signal strength are carried out in a typical Norwegian area in this work. Based on the data obtained from the measurements, a simulator with a recent empirical propagation model, namely, ITU-R P.1546-5, has been calibrated. The fin…
An Efficient Wiener Path Integral Technique Formulation for Stochastic Response Determination of Nonlinear MDOF Systems
2015
The recently developed approximate Wiener path integral (WPI) technique for determining the stochastic response of nonlinear/hysteretic multi-degree-of-freedom (MDOF) systems has proven to be reliable and significantly more efficient than a Monte Carlo simulation (MCS) treatment of the problem for low-dimensional systems. Nevertheless, the standard implementation of the WPI technique can be computationally cumbersome for relatively high-dimensional MDOF systems. In this paper, a novel WPI technique formulation/implementation is developed by combining the “localization” capabilities of the WPI solution framework with an appropriately chosen expansion for approximating the system response PDF…
The Impact of Internet and Social Media Use on Well-Being
2021
The present research examines the longitudinal average impact of frequency of use of Internet and social networking sites (SNS) on subjective well-being of adolescents in Germany. Based on five-wave panel data that cover a period of nine years, we disentangle between-person and within-person effects of media use on depressive symptomatology and life satisfaction as indicators of subjective well-being. Additionally, we control for confounders such as TV use, self-esteem, and satisfaction with friends. We found that frequency of Internet use in general and use of SNS in particular is not substantially related subjective well-being. The explanatory power of general Internet use or SNS use to p…
A two-layer security model for accessing multimedia content in social networks
2016
La seguridad de un sitio web es hoy en día una de las principales preocupaciones de los administradores de sistemas. La seguridad es también el reto más importante al que se enfrentan los desarrolladores web a la hora de diseñar una plataforma fiable que ofrezca servicios a los usuarios públicos. Es bien sabido que el contenido multimedia en la web está en continuo crecimiento y, recientemente, este tipo de medios se utiliza cada vez más en las redes sociales. El acceso a los contenidos multimedia en el contexto de las redes sociales debe ser fácil y seguro. En este artículo se presenta un modelo de seguridad con capacidad semántica para el acceso a contenidos multimedia en las redes social…
The Impact of a Mathematics Bridging Intervention on the Inclusivity of a University Economics Programme
2021
The inclusivity of all students in the University Economics programme is in danger due to a high failure rate in the first-year mathematics course. This study investigates whether participation in a bridging course, and what aspects of it, can contribute to equal opportunities and increased inclusivity in the Mathematics for Economists course, and henceforth reduce the failure rate. It adds to the meager European literature on remedial course effectiveness. Through the use of ordinary least square regression analyses, a significant positive effect of participation in the bridging course was found for the student group as a whole. Furthermore, the results indicated that participation was par…
A Multilevel Analysis of Economic Literacy Among International Students
2021
International student mobility has increased in the past years. The inclusion of a highly heterogeneous group of students requires updated recruitment and admission strategies. A particularly vulnerable group of international students are refugees, who have an exceptionally high risk of dropping out of their studies. We present an entrance assessment of incoming international students from 77 countries who are at the beginning of their studies in Germany. Based on this unique sample, we examine (i) whether there are systematic country-specific effects on the economic literacy of beginning students of business and economics and (ii) whether refugee students differ from the group of internati…