A consumer-based model of competitive diffusion: the multiplicative effects of global and local network externalities

2005 ◽  
Vol 15 (3) ◽  
pp. 273-295 ◽  
Author(s):  
Masaki Tomochi ◽  
Hiroaki Murata ◽  
Mitsuo Kono
Keyword(s):  
Network Externalities ◽  
Local Network ◽  
Global And Local ◽  
Multiplicative Effects ◽  
Competitive Diffusion

scholarly journals Network study of responses to unusualness and psychological stress during the COVID-19 outbreak in Korea

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246894
Author(s):  
Seunghyong Ryu ◽  
In-Hoo Park ◽  
Mina Kim ◽  
Yu-Ri Lee ◽  
Jonghun Lee ◽  
...  
Keyword(s):  
Psychological Stress ◽  
Perceived Stress ◽  
Economic Loss ◽  
Local Network ◽  
Daily Lives ◽  
Correlation Networks ◽  
Negative Edge ◽  
Huge Impact ◽  
Psychosocial Responses ◽  
Global And Local

The dramatic changes in people’s daily lives caused by the 2019 coronavirus (COVID-19) pandemic have had a huge impact on their emotions and behaviors. This study aimed to examine psychosocial responses to COVID-19 using network analysis. A total of 1,500 urban residents of South Korea, selected from an online public panel, were surveyed using self-rating questionnaires addressing daily life changes, fear of infection, and distress related to COVID-19. Participants also completed a 10-item Perceived Stress Scale survey. We constructed regularized partial correlation networks, estimated global and local network metrics, tested network accuracy and stability, and compared the estimated networks between men and women. The network of the psychosocial responses consisted of 24 nodes that were classified into five groups: ‘fear of infection’, ‘difficulty with outside activities’, ‘economic loss’, ‘altered eating and sleeping’, and ‘adaptive stress’. The node centralities indicated that ‘distress in obtaining daily necessities’ and ‘concern about harming others’ were the most important issues in people’s responses to COVID-19. These nodes were connected by a negative edge, reflecting individual- and community-level issues, respectively. The overall level of perceived stress was linked to the network by the connection node ‘anger toward others or society’, which was associated with economic problems in men, but with distress from changes in daily activities in women. The results suggest that two contrasting feelings—personal insecurity regarding basic needs and a collectivistic orientation—play roles in the response to unusual experiences and distress due to COVID-19. This study also showed that public anger could arise from the psychological stress under the conditions imposed by COVID-19.

scholarly journals Competition with Local Network Externalities

2009 ◽  
Author(s):  
Øystein Fjeldstad ◽  
Espen R. Moen ◽  
Christian Riis
Keyword(s):  
Network Externalities ◽  
Local Network

scholarly journals The network structure of mathematical knowledge according to the Wikipedia, MathWorld, and DLMF online libraries

2014 ◽  
Vol 2 (3) ◽  
pp. 367-386
Author(s):  
FLAVIO B. GONZAGA ◽  
VALMIR C. BARBOSA ◽  
GERALDO B. XEXÉO
Keyword(s):  
Network Structure ◽  
Mathematical Knowledge ◽  
Directed Graphs ◽  
Power Laws ◽  
Local Features ◽  
Local Network ◽  
Connected Component ◽  
Strongly Connected ◽  
Global And Local ◽  
The Web

AbstractWe study the network structure of Wikipedia (restricted to its mathematical portion), MathWorld, and DLMF. We approach these three online mathematical libraries from the perspective of several global and local network-theoretic features, providing for each one the appropriate value or distribution, along with comparisons that, if possible, also include the whole of the Wikipedia or the Web. We identify some distinguishing characteristics of all three libraries, most of them supposedly traceable to the libraries' shared nature of relating to a very specialized domain. Among these characteristics are the presence of a very large strongly connected component in each of the corresponding directed graphs, the complete absence of any clear power laws describing the distribution of local features, and the rise to prominence of some local features (e.g., stress centrality) that can be used to effectively search for keywords in the libraries.

scholarly journals Hunter–gatherer foraging networks promote information transmission

2021 ◽  
Vol 8 (12) ◽  
Author(s):  
Ketika Garg ◽  
Cecilia Padilla-Iglesias ◽  
Nicolás Restrepo Ochoa ◽  
V. Bleu Knight
Keyword(s):  
Information Transmission ◽  
Environmental Conditions ◽  
Information Exchange ◽  
Central Place ◽  
Local Network ◽  
Mobility Strategies ◽  
Population Sizes ◽  
Spatial Use ◽  
Complex Culture ◽  
Global And Local

Central-place foraging (CPF), where foragers return to a central location (or home), is a key feature of hunter–gatherer social organization. CPF could have significantly changed hunter–gatherers’ spatial use and mobility, altered social networks and increased opportunities for information-exchange. We evaluated whether CPF patterns facilitate information-transmission and considered the potential roles of environmental conditions, mobility strategies and population sizes. We built an agent-based model of CPF where agents moved according to a simple optimal foraging rule, and could encounter other agents as they moved across the environment. They either foraged close to their home within a given radius or moved the location of their home to new areas. We analysed the interaction networks arising under different conditions and found that, at intermediate levels of environmental heterogeneity and mobility, CPF increased global and local network efficiencies as well as the rate of contagion-based information-transmission. We also found that central-place mobility strategies can further improve information transmission in larger populations. Our findings suggest that the combination of foraging and movement strategies, as well as the environmental conditions that characterized early human societies, may have been a crucial precursor in our species’ unique capacity to innovate, accumulate and rely on complex culture.

scholarly journals The sensitivity of network statistics to incomplete electrode sampling on intracranial EEG

2020 ◽  
Vol 4 (2) ◽  
pp. 484-506 ◽  
Author(s):  
Erin C. Conrad ◽  
John M. Bernabei ◽  
Lohith G. Kini ◽  
Preya Shah ◽  
Fadi Mikhail ◽  
...  
Keyword(s):  
Network Models ◽  
Local Network ◽  
Patient Specific ◽  
Intracranial Eeg ◽  
Targeted Interventions ◽  
Depth Electrodes ◽  
The Difference ◽  
Network Metrics ◽  
Global And Local ◽  
Incomplete Sampling

Network neuroscience applied to epilepsy holds promise to map pathological networks, localize seizure generators, and inform targeted interventions to control seizures. However, incomplete sampling of the epileptic brain because of sparse placement of intracranial electrodes may affect model results. In this study, we evaluate the sensitivity of several published network measures to incomplete spatial sampling and propose an algorithm using network subsampling to determine confidence in model results. We retrospectively evaluated intracranial EEG data from 28 patients implanted with grid, strip, and depth electrodes during evaluation for epilepsy surgery. We recalculated global and local network metrics after randomly and systematically removing subsets of intracranial EEG electrode contacts. We found that sensitivity to incomplete sampling varied significantly across network metrics. This sensitivity was largely independent of whether seizure onset zone contacts were targeted or spared from removal. We present an algorithm using random subsampling to compute patient-specific confidence intervals for network localizations. Our findings highlight the difference in robustness between commonly used network metrics and provide tools to assess confidence in intracranial network localization. We present these techniques as an important step toward translating personalized network models of seizures into rigorous, quantitative approaches to invasive therapy.

scholarly journals Network analysis shows decreased ipsilesional structural connectivity in glioma patients

2021 ◽  
Author(s):  
Lucius Samo Fekonja ◽  
Ziqian Wang ◽  
Alberto Cacciola ◽  
Timo Roine ◽  
Baran D. Aydogan ◽  
...  
Keyword(s):  
Network Analysis ◽  
Information Transfer ◽  
Structural Connectivity ◽  
Local Network ◽  
Neurological Assessment ◽  
Multiple Systems ◽  
Local Efficiency ◽  
Network Properties ◽  
Global And Local ◽  
Theoretical Analyses

Gliomas that infiltrate networks and systems, such as the motor system, often lead to substantial functional impairment in multiple systems. Network-based statistics (NBS) allow to 25 assess local network differences (1) and graph theoretical analyses (2) enable investigation of global and local network properties. Here, we used network measures to characterize gliomarelated decreases in structural connectivity by comparing the ipsi- with the contralesional hemispheres of patients and correlated findings with neurological assessment. We found that lesion location resulted in differential impairment of both short and long 30 connectivity patterns. Network analysis showed reduced global and local efficiency in the ipsilesional hemisphere compared to the contralesional hemispheric networks. In network science, reduced global and local efficiency reflect the impairment of information transfer across different regions of a network.

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