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Can we migrate COVID-19 spreading risk?

Qingyan Chen

《环境科学与工程前沿（英文）》 2021年第15卷第3期 doi: 10.1007/s11783-020-1328-8

摘要： Abstract It is well recognized that Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus could be spread through touch and large droplets. However, we may have under-estimated the disease transmission by small droplets or aerosols that contain SARS-CoV-2 virus. Social distancing in public transport vehicles, such as airplanes, is not feasible. It is also not possible to wear masks in restaurant. This paper recommended wearing masks in airplanes and use partition screens in the middle of a table in a restaurant to reduce the infection caused by SARS-CoV-2 virus. Advanced ventilation systems, such as personalized ventilation and displacement ventilation, are strongly recommended for transport vehicles and buildings.

关键词： Airborne transmission Ventilation Masks Partitions

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Unnormalized and normalized forms of gefura measures in directed and undirected networks

Raf GUNS,Ronald ROUSSEAU

《信息与电子工程前沿（英文）》 2015年第16卷第4期页码 311-320 doi: 10.1631/FITEE.1400425

摘要： In some networks nodes belong to predefined groups (e.g., authors belong to institutions). Common network centrality measures do not take this structure into account. Gefura measures are designed as indicators of a node’s brokerage role between such groups. They are defined as variants of betweenness centrality and consider to what extent a node belongs to shortest paths between nodes from different groups. In this article we make the following new contributions to their study: (1) We systematically study unnormalized gefura measures and show that, next to the ‘structural’ normalization that has hitherto been applied, a ‘basic’ normalization procedure is possible. While the former normalizes at the level of groups, the latter normalizes at the level of nodes. (2) Treating undirected networks as equivalent to symmetric directed networks, we expand the definition of gefura measures to the directed case. (3) It is shown how Brandes’ algorithm for betweenness centrality can be adjusted to cover these cases.

关键词： Networks subdivided in groups Partitions Gefura measures Q-measures Brokerage role Directed and undirected networks Brandes’ algorithm