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Physica
North-Holland
Physica

North-Holland

0378-4371

Physica/Journal Physica
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    Modelling epidemic spreading in structured organisations

    Kuikka, Vesa
    23页
    查看更多>>摘要:Modelling epidemic spreading in a population or in organisations is important in planning preventive measures and allocating resources for treating infected individuals in hospitals. We present a structural spreading model capable of describing detailed structures of organisations. We discuss methods and results with the help of an example organisation. The example organisation is a real-world organisation but our main focus is on presenting modelling approaches. Our spreading model is designed for describing indirect virus spreading mechanics via respiratory droplets and aerosols from an infected person rather than spreading via physical person to person contacts. To this end, we propose a new complex contagion model that describes the spreading process alike a social interaction process. Different preventive measures and their combinations can be compared by our model. We show that the optimised preventive measures in the complex contagion model can be different from the corresponding simple contagion model. We study the effects of limiting contacts between different organisation structures and shortening chains of infection together with general risk mitigation actions. Out-centrality, in-centrality and betweenness measures are used in analysing different aspects of epidemic spreading. Examples of calculating community immunity are presented, in which strategies based on out-centrality and betweenness measures are prioritised. (C)& nbsp;2022 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

    Group-bipartite consensus of heterogeneous multi-agent systems over signed networks

    Liu, ChaoLi, RongLiu, Bo
    11页
    查看更多>>摘要:In this paper, the concept of group-bipartite consensus is put forward for heterogeneous multi-agent systems (MASs) over signed networks. It refers to the situation that a MAS achieves the group consensus and the bipartite consensus simultaneously. An effective protocol is proposed to gain the aim of group-bipartite consensus for a class of heterogeneous MASs composed of first-order and second-order dynamic agents. Finally, some numerical simulations are presented to verify the theoretical results. (C) 2021 Elsevier B.V. All rights reserved.

    Epidemiological modeling for COVID-19 spread in India with the effect of testing

    Singh, AnuragArquam, Md
    24页
    查看更多>>摘要:A novel coronavirus has resulted in an outbreak of viral pneumonia in China. Personto-person transmission has been demonstrated, but, to our knowledge, the spreading of novel coronavirus takes place due to an asymptomatic carrier. Most models are not considering testing and underlying network topology that shows the spreading pattern. By failing to integrate testing into the epidemiological model, models missed a vital opportunity to better understand the role of asymptomatic infection in transmission. In this work, we propose a model considering testing as well as asymptomatic infection considering underlying network topology. We extract the transmission parameters from the data set of COVID-19 of India and apply those parameters in our proposed model. The simulation results support our theoretical derivations, which show the impact of testing and asymptomatic carrier in infection spreading. (c) 2021 Elsevier B.V. All rights reserved.

    Size distribution of states, counties, and cities in the USA: New inequality form information

    Grachev, Gennady A.
    10页
    查看更多>>摘要:In this article, we propose a new approach for studying the patterns of size distribution in settlement systems, based on the analysis of the shape of the Pareto curve (PC). To study the shape of the PC, we used the Gini coefficient, the asymmetry coefficient, and, by analogy with the physics of phase transitions, critical exponent - the index of the PC degree in the neighborhood of zero. An empirical analysis of the PC of various levels of aggregation in the US settlement system has been performed. The form of size distribution of states was studied by decades from 1790 to 2010. The spatial analysis of the PC shape for counties and cities was performed for 2010. The results of an empirical study showed that the PC of the states had left-hand asymmetry over 220 years. The PC of counties and cities had both right-hand and left-hand asymmetries. The obtained results explain in which cases the Pareto distribution having a PC with right-hand asymmetry, and the lognormal distribution with a symmetric PC may not correspond objectively to real settlement systems. As an alternative to power-series distribution and lognormal distribution, we considered an analytically simple two-parameter model with a wide range of PC asymmetry that combines the properties of power-series distribution and lognormal distribution. Verification of the model showed that it adequately described the size of settlements in homogeneous settlement systems. (C) 2022 Elsevier B.V. All rights reserved.