Search results for "dynamic network"
showing 8 items of 18 documents
Dynamic networks of physiologic interactions of brain waves and rhythms in muscle activity.
2022
The brain plays a central role in facilitating vital body functions and in regulating physiological and organ systems, including the skeleto-muscular and locomotor system. While neural control is essential to synchronize and coordinate activation of various muscle groups and muscle fibers within muscle groups in relation to body movements and distinct physiologic states, the dynamic networks of brain-muscle interactions have not been explored and the complex regulatory mechanism of brain-muscle control remains unknown. Here we present a first study of network interactions between brain waves at different cortical locations and peripheral muscle activity across key physiologic states - wake,…
Graphical models for estimating dynamic networks
2012
Het bepalen van dynamische netwerken met behulp van data is een actief onderzoeksgebied, met name in de systeem biologie. Het schatten van de structuur van een netwerk heeft te maken met het bepalen van de aan of afwezigheid van een relatie tussen de hoekpunten in de graaf. Grafische modellen definiëren deze relaties via conditionele afhankelijkheid. In Gaussiaanse grafische modellen (GGM) wordt verondersteld dat de hoekpunten een normale verdeling volgen. Dit heeft grote voordelen vanwege de computationele handelbaarheid van GGM. Standaard GGM zijn echter niet bruikbaar om grote netwerken te bestuderen, i.e. als het aantal waarnemingen minder is dan het aantal hoekpunten van de graaf. Rece…
Dynamic network identification from non-stationary vector autoregressive time series
2018
Learning the dynamics of complex systems features a large number of applications in data science. Graph-based modeling and inference underpins the most prominent family of approaches to learn complex dynamics due to their ability to capture the intrinsic sparsity of direct interactions in such systems. They also provide the user with interpretable graphs that unveil behavioral patterns and changes. To cope with the time-varying nature of interactions, this paper develops an estimation criterion and a solver to learn the parameters of a time-varying vector autoregressive model supported on a network of time series. The notion of local breakpoint is proposed to accommodate changes at individu…
Overlapping Community Structure in Co-authorship Networks: A Case Study
2014
Community structure is one of the key properties of real-world complex networks. It plays a crucial role in their behaviors and topology. While an important work has been done on the issue of community detection, very little attention has been devoted to the analysis of the community structure. In this paper, we present an extensive investigation of the overlapping community network deduced from a large-scale co-authorship network. The nodes of the overlapping community network represent the functional communities of the co-authorship network, and the links account for the fact that communities share some nodes in the co-authorship network. The comparative evaluation of the topological prop…
Structural and Gelation Characteristics of Metallo-Supramolecular Polymer Model-Network Hydrogels Probed by Static and Dynamic Light Scattering
2021
Supramolecular polymer gels are a promising class of materials whose polymer components are connected by transient bonds such as metal–ligand interactions, thereby spanning a dynamic network throug...
Change Is Good, But Not Too Much: Dynamic Positioning in the Interfirm Network and New Product Development
2018
This research considers the dynamic positioning of an enterprise in an interfirm network and its propensity for new product development. Specifically, we explore how firms reconcile the dichotomy between central and structural holes network positions, by dynamically shifting from a central to a structural holes position (and vice versa) over time. By grounding this research in network dynamics theory, we argue how prior strong central (structural holes) network positions in the interfirm network increase the likelihood the firm will benefit from structural holes (central) positions in the following time period. We also propose that these positions can be modeled by an inverted U-shaped rela…
The upcoming rise of SMEs in cross-border public procurement: is it a matter of networking capabilities?.
2022
La participación de las SME en licitaciones públicas es un tema recurrente en la literatura académica reciente, sin embargo, se ha prestado poca atención a la participación de las PYME en licitaciones internacionales o transfronterizas. Las SME que quieren participar en una licitación pública internacional debe superar barreras internas y externas que difcultan la tarea y minimizan las posibilidades de que le sea concedida la licitación. En este contexto, las capacidades dinámicas son fundamentales para que las PYME puedan enfrentarse y resolver dichas barreras en el contexto internacional. Especialmente son las capacidades de establecer redes las que pueden hacer que las PYME aumenten su d…
Deconstructing and reconstructing resilience: a dynamic network approach
2019
Resilience is still often viewed as a unitary personality construct that, as a kind of anti-nosological entity, protects individuals against stress-related mental problems. However, increasing evidence indicates that the maintenance of mental health in the face of adversity results from complex and dynamic processes of adaptation to stressors that involve the activation of several separable protective factors. Such resilience factors can reside at biological, psychological and social levels and may include stable predispositions (such as genotype or personality traits) and malleable properties, skills, capacities or external circumstances (such as gene expression patterns, emotion regulatio…