Search results for " connectivity"

Measuring frequency domain granger causality for multiple blocks of interacting time series

2011

In the past years, several frequency-domain causality measures based on vector autoregressive time series modeling have been suggested to assess directional connectivity in neural systems. The most followed approaches are based on representing the considered set of multiple time series as a realization of two or three vector-valued processes, yielding the so-called Geweke linear feedback measures, or as a realization of multiple scalar-valued processes, yielding popular measures like the directed coherence (DC) and the partial DC (PDC). In the present study, these two approaches are unified and generalized by proposing novel frequency-domain causality measures which extend the existing meas…

Staying connected and feeling less exhausted : The autonomy benefits of after‐hour connectivity

2023

This study investigates the longitudinal relationship between after-hour connectivity, autonomy and exhaustion. In doing so, we seek to illuminate the role of individuals' connectivity to work in relation to their autonomy and well-being. We juxtapose different effective directions of the relationship between connectivity and autonomy to shed light on whether and how connectivity and autonomy are related to employees' well-being. This is important because research has both often problematized after-hour connectivity and suggested that connectivity is an inherent feature of contemporary workplaces that may benefit employees. In this study, we hypothesize that after-hour connectivity increase…

Deriving electrophysiological brain network connectivity via tensor component analysis during freely listening to music

2020

Recent studies show that the dynamics of electrophysiological functional connectivity is attracting more and more interest since it is considered as a better representation of functional brain networks than static network analysis. It is believed that the dynamic electrophysiological brain networks with specific frequency modes, transiently form and dissolve to support ongoing cognitive function during continuous task performance. Here, we propose a novel method based on tensor component analysis (TCA), to characterize the spatial, temporal, and spectral signatures of dynamic electrophysiological brain networks in electroencephalography (EEG) data recorded during free music-listening. A thr…

Synergetic and redundant information flow detected by unnormalized Granger causality: application to resting state fMRI

2015

Objectives: We develop a framework for the analysis of synergy and redundancy in the pattern of information flow between subsystems of a complex network. Methods: The presence of redundancy and/or synergy in multivariate time series data renders difficult to estimate the neat flow of information from each driver variable to a given target. We show that adopting an unnormalized definition of Granger causality one may put in evidence redundant multiplets of variables influencing the target by maximizing the total Granger causality to a given target, over all the possible partitions of the set of driving variables. Consequently we introduce a pairwise index of synergy which is zero when two in…

Weak effects of geolocators on small birds: A meta-analysis controlled for phylogeny and publication bias

2020

Abstract Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light‐level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta‐analyses did not evaluate unpublished data and impact of multiple life‐history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewe…

2020

Introduction Adolescents have experienced decreased aerobic fitness levels and insufficient physical activity levels over the past decades. While both physical activity and aerobic fitness are related to physical and mental health, little is known concerning how they manifest in the brain during this stage of development, characterized by significant physical and psychosocial changes. The aim of the study is to examine the associations between both physical activity and aerobic fitness with brains' functional connectivity. Methods Here, we examined how physical activity and aerobic fitness are associated with local and interhemispheric functional connectivity of the adolescent brain (n = 59…

Comparing the applicability of two learning theories for knowledge transfer in information system implementation training

2004

This study reviews two traditional learning theories from the viewpoint of knowledge transfer in information system implementation training. The main goal of this study is to determine which is more applicable from the view of knowledge transfer in this context. In this study, behaviourist learning theory is found suitable for the transfer of data and information. Being more learner-centered, constructivist learning theory suits better for information system implementation training, as it enables combining system specific knowledge with knowledge of the existing organisational processes. This creates new organisation-specific knowledge necessary for the effective use of the information syst…

SUGGESTIONS OF SCENARIOS FOR RESTORING LONGITUDINAL CONNECTIVITY TO SUSTAIN FISH FAUNA MIGRATION UPSTREAM AND DOWNSTREAM OF APAHIDA BOTTOM SILL

2016

Rivers and their corridors form complex ecosystems that include adjacent land, flora and fauna and the actual courses of water. Given the ecological criteria for prioritizing the rehabilitation of longitudinal continuity of watercourses recommended by the International Commission for Protection of the Danube River (ICPDR) (Appendix 1) and starting from the analysis of the Management Plan to ensure longitudinal continuity of watercourses in Some?-Tisa River Area (Annex 9.17.a in BMP – Basin Management Plan) there have been proposed several scenarios in order to facilitate fish species migration above the bottom sill from Apahida. The selected case study is focused on the mentioned discharge …

An introduction to knowledge computing

2014

This paper deals with the challenges related to self-management and evolution of massive knowledge collections. We can assume that a self-managed knowledge graph needs a kind of a hybrid of: an explicit declarative self-knowledge (as knowledge about own properties and capabilities) and an explicit procedural self-knowledge (as knowledge on how to utilize own properties and the capabilities for the self-management).We offer an extension to a traditional RDF model of describing knowledge graphs according to the Semantic Web standards so that it will also allow to a knowledge entity to autonomously perform or query from remote services different computational executions needed. We also introdu…

Dissemination protocol for Heterogeneous Cooperative Vehicular Networks

2012

International audience; The difficulties associated with network connectivity, unreliable channels, and city environment characteristics make data dissemination task in vehicular urban networks a real challenge. Recently, some interesting solutions have been proposed to perform data dissemination in this environment. Starting from the analysis of these solutions, we present a new dissemination protocol named DHVN (Dissemination protocol for Heterogeneous Cooperative Vehicular Networks) that considers: (i) roads topology, (ii) network connectivity and possible partitioning in case of low traffic density, and (iii) heterogeneous communication capabilities of the vehicles. We compare our proto…