Search results for "Network dynamics"

Iberian Neolithic Networks: The Rise and Fall of the Cardial World

2017

Recent approaches have described the evolutionary dynamics of the first Neolithic societies as a cycle of rise and fall. Several authors, using mainly c14 dates as a demographic proxy, identified a general pattern of a boom in population coincident with the arrival of food production economies followed by a rapid decline some centuries afterwards in multiple European regions. Concerning Iberia, we also noted that this phenomenon correlates with an initial development of archaeological entities (i.e., ‘cultures’) over large areas (e.g. the Impresso-Cardial in West Mediterranean), followed by a phase of ‘cultural fragmentation’ by the end of Early Neolithic. These results in a picture of high…

Nonlinear network dynamics for interconnected micro-grids

2018

Abstract This paper deals with transient stability in interconnected micro-grids. The main challenge is to understand the impact of the connectivity of the graph and model nonlinearities on transient and steady-state behavior of the system as a whole. The contribution of this paper is three-fold. First, we provide a robust classification of transient dynamics for different intervals of the parameters for a single micro-grid. We prove that underdamped dynamics and oscillations arise when the damping coefficient is below a certain threshold which we calculate explicitly as function of the product between the inertia coefficient and the synchronization parameter. Second, for interconnected mic…

Stochastic sampling effects favor manual over digital contact tracing.

2020

Isolation of symptomatic individuals, tracing and testing of their nonsymptomatic contacts are fundamental strategies for mitigating the current COVID-19 pandemic. The breaking of contagion chains relies on two complementary strategies: manual reconstruction of contacts based on interviews and a digital (app-based) privacy-preserving contact tracing. We compare their effectiveness using model parameters tailored to describe SARS-CoV-2 diffusion within the activity-driven model, a general empirically validated framework for network dynamics. We show that, even for equal probability of tracing a contact, manual tracing robustly performs better than the digital protocol, also taking into accou…

Increased structural white and grey matter network connectivity compensates for functional decline in early multiple sclerosis

2016

Background: The pathology of multiple sclerosis (MS) consists of demyelination and neuronal injury, which occur early in the disease; yet, remission phases indicate repair. Whether and how the central nervous system (CNS) maintains homeostasis to counteract clinical impairment is not known. Objective: We analyse the structural connectivity of white matter (WM) and grey matter (GM) networks to understand the absence of clinical decline as the disease progresses. Methods: A total of 138 relapsing–remitting MS patients (classified into six groups by disease duration) and 32 healthy controls were investigated using 3-Tesla magnetic resonance imaging (MRI). Networks were analysed using graph the…

Plasticity of brain wave network interactions and evolution across physiologic states

2015

Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions repre…

Recent Advances in Complex Networks Theories with Applications

2014

Structural Dynamics and Intentional Governance in Strategic Interfirm Network Evolution

2015

This paper aims to shed light on the drivers underlying the role and scope of intentional governance of the structural dynamics of whole interfirm networks. Prior research has distinguished networks that are emergent from networks that are orchestrated. While empirical studies have shown situations in which the role and scope of intentional governance of whole interfirm networks has changed in time, and there is a growing interest regards the endogenous drivers of network dynamics, the dimensions that influence intentional governance of network structure dynamics and the way this is carried out remain still to be elucidated. In order to pinpoint these drivers, we leverage the models of netw…

Information Decomposition in Multivariate Systems: Definitions, Implementation and Application to Cardiovascular Networks

2016

The continuously growing framework of information dynamics encompasses a set of tools, rooted in information theory and statistical physics, which allow to quantify different aspects of the statistical structure of multivariate processes reflecting the temporal dynamics of complex networks. Building on the most recent developments in this field, this work designs a complete approach to dissect the information carried by the target of a network of multiple interacting systems into the new information produced by the system, the information stored in the system, and the information transferred to it from the other systems; information storage and transfer are then further decomposed into amou…

Methodological Approach to Studying the dynamics of production networks: a Discrete Event Simulation Model

2013

This paper shows how discrete-event simulation represents an appropriate tool for approaching the dynamics of production networks. Three important factors influencing production network dynamics, specifically finite production capacity, manufacturing lead time, and its variability are discussed and a basic discrete-event simulation model is presented. Such model, which in its basic form represents a simple retail/distribution two-stage supply chain, is then extended in order to take into account those factors that can not be included in a classical control theoretical model.

Between Self-Organizing and Accelerating Networks: Untangling Strategic Networks Cognitive Dynamics

2010

This paper aims to detect the crucial determinants and processes that shape the emergence and evolution of interfirm network cognitive morphology. We pinpoint three relatively distinct but coexistent levels which define the fundamental structure of the network: the microsystemic (or the single firm) level; the mesosystemic (or the groups of firms within the network) level; and the macrosystemic (or the overarching network) level. Then, we integrate the complex system perspective (Morin, 1977; Prigogine & Stengers, 1984; Anderson, 1999) applied to networks with studies regarding theoretical models that elucidate network structuring and dynamics cultivated in the new “science of networks”…