scholarly journals Structural Models of Cortical Networks with Long-Range Connectivity

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Nicole Voges ◽  
Ad Aertsen ◽  
Stefan Rotter
Keyword(s):  
Graph Theory ◽  
Long Range ◽  
Neuronal Activity ◽  
Structural Models ◽  
Network Models ◽  
Embedded Networks ◽  
Stochastic Graph ◽  
Random Connectivity ◽  
Activity Dynamics ◽  
Specific Distance

Most current studies of neuronal activity dynamics in cortex are based on network models with completely random wiring. Such models are chosen for mathematical convenience, rather than biological grounds, and additionally reflect the notorious lack of knowledge about the neuroanatomical microstructure. Here, we describe some families of new, more realistic network models and explore some of their properties. Specifically, we consider spatially embedded networks and impose specific distance-dependent connectivity profiles. Each of these network models can cover the range from purely local to completely random connectivity, controlled by a single parameter. Stochastic graph theory is then used to describe and analyze the structure and the topology of these networks.

Graph Theory

2020 ◽  
pp. 354-370
Author(s):  
Seethalakshmi R.
Keyword(s):  
Graph Theory ◽  
Market Structure ◽  
Financial Market ◽  
Network Theory ◽  
Financial Analysts ◽  
Structural Models ◽  
Topological Properties ◽  
Strategic Decisions ◽  
Analytical Geometry ◽  
Innovative Methods

Mathematics acts an important and essential need in different fields. One of the significant roles in mathematics is played by graph theory that is used in structural models and innovative methods, models in various disciplines for better strategic decisions. In mathematics, graph theory is the study through graphs by which the structural relationship studied with a pair wise relationship between different objects. The different types of network theory or models or model of the network are called graphs. These graphs do not form a part of analytical geometry, but they are called graph theory, which is points connected by lines. The various concepts of graph theory have varied applications in diverse fields. The chapter will deal with graph theory and its application in various financial market decisions. The topological properties of the network of stocks will provide a deeper understanding and a good conclusion to the market structure and connectivity. The chapter is very useful for academicians, market researchers, financial analysts, and economists.

A framework to learn graph theory using simple wireless network models

2016 ◽  
Vol 24 (6) ◽  
pp. 843-852 ◽  
Author(s):  
Adriana Dapena ◽  
Francisco J. Vázquez-Araujo ◽  
Paula M. Castro ◽  
Maria J. Souto-Salorio
Keyword(s):  
Graph Theory ◽  
Wireless Network ◽  
Network Models

scholarly journals Between Imitation and Embeddedness: Three Types of Polish Alternative Food Networks

2019 ◽  
Vol 11 (24) ◽  
pp. 7059 ◽  
Author(s):  
Wojciech Goszczyński ◽  
Ruta Śpiewak ◽  
Aleksandra Bilewicz ◽  
Michał Wróblewski
Keyword(s):  
Secondary Analysis ◽  
Network Models ◽  
Social Contexts ◽  
Alternative Food ◽  
Alternative Food Networks ◽  
Embedded Networks ◽  
The Past ◽  
The Social ◽  
Food Networks ◽  
Mixed Networks

The purpose of this article is to present the specific character of Alternative Food Networks (AFNs) in Poland as one of the countries of Central and Eastern Europe (CEE). We refer to the issue increasingly debated in the social sciences, that is, how to translate academic models embedded in specific social contexts to other contexts, as we trace the process of adapting ideas and patterns of AFNs developed in the West to the semi-peripheral context of CEE countries. Drawing on the theory of social practices, we divide the analysis into three essential areas: The ideas of the network, its materiality, and the activities within the network. We have done secondary analysis of the research material, including seven case studies the authors worked on in the past decade. We distinguish three network models—imitated, embedded and mixed—which allow us to establish a specific post-transformational AFN growth theory. Particular attention should be paid to the type of embedded networks, as they highlight the possibility of local and original forms of AFNs. Mixed networks show that ideas imported from abroad need to be considered in juxtaposition and connection with local circumstances.

scholarly journals Hybrid Method For Forecasting A Steel Mill's Sales

2011 ◽  
Vol 5 (4) ◽  
Author(s):  
Bogdan Rebiasz
Keyword(s):  
Probability Distribution ◽  
Long Range ◽  
Delphi Method ◽  
Fuzzy Number ◽  
Building Materials ◽  
Structural Models ◽  
Triangular Fuzzy Number ◽  
Developmental Trends ◽  
Fuzzy Delphi Method ◽  
Fuzzy Delphi

This paper presents a proposal of long range steel mill's sales forecasting method. It can be also used in other sectors of steel industry, and (after minor modifications) in enterprises operating in a power industry, building materials industry, plastics industry etc. Heuristic methods are often used in long range forecasting. In the proposed method few parameters are predicted with fuzzy Delphi method. It results in the forecasts in form of fuzzy triangular numbers. Transformation of possibility distribution, generated by fuzzy number, into a probability distribution enables to integrate forecasts obtained from fuzzy Delphi method with those prepared with structural models and developmental trends models. A computer simulation is used to determine sales forecast's expected value and probability distribution. In case of structural models and developmental trends models a simulation with re-estimation has been used. The method presented in this paper is used to generate random numbers from a set determined by triangular fuzzy number.

scholarly journals Vigilance and behavioral state-dependent modulation of cortical neuronal activity throughout the sleep/wake cycle

2021 ◽  
Author(s):  
Aurelie Brecier ◽  
Melodie Borel ◽  
Nadia Urbain ◽  
Luc J Gentet
Keyword(s):  
Neuronal Activity ◽  
Rem Sleep ◽  
Barrel Cortex ◽  
Field Potential ◽  
Nrem Sleep ◽  
Inhibitory Neurons ◽  
Sleep Stages ◽  
Theta Waves ◽  
Physiological Diversity ◽  
Activity Dynamics

GABAergic inhibitory neurons, through their molecular, anatomic and physiological diversity, provide a substrate for the modulation of ongoing cortical circuit activity throughout the sleep-wake cycle. Here, we investigated neuronal activity dynamics of parvalbumin (PV), vasoactive intestinal polypeptide (VIP) and somatostatin (SST) neurons in naturally-sleeping head-restrained mice at the level of layer 2/3 of the primary somatosensory barrel cortex of mice. Through calcium-imaging and targeted single-unit loose-patch or whole-cell recordings, we found that PV action potential (AP) firing activity was largest during both NREM (non-rapid eye movement) and REM sleep stages, that VIP neurons were activated during REM sleep and that the overall activity of SST neurons remained stable throughout the sleep/wake cycle. Analysis of neuronal activity dynamics uncovered rapid decreases in PV cell firing at wake onset followed by a progressive recovery during wake. Simultaneous local field potential (LFP) recordings further revealed that, except for SST neurons, a large proportion of neurons were modulated by ongoing delta and theta waves. During NREM sleep spindles, PV and SST activity increased and decreased, respectively. Finally, we uncovered the presence of whisking behavior in mice during REM sleep and show that the activity of VIP and SST is differentially modulated during awake and sleeping whisking bouts, which may provide a neuronal substrate for internal brain representations occurring during sleep.

Structural models in epidemiology: an introductory investigation

1971 ◽  
Vol 3 (02) ◽  
pp. 196-198
Author(s):  
Petre Tautu
Keyword(s):  
Graph Theory ◽  
Mathematical Models ◽  
Structural Models

The purpose of this paper is to bring to the attention of epidemiologists the possibility of setting up and utilizing structural models, more precisely, mathematical models based on graph theory. We shall present the first general results in this investigation using some statements and definitions.

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