407 research outputs found

    Long-Range Connections in Transportation Networks

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    Since its recent introduction, the small-world effect has been identified in several important real-world systems. Frequently, it is a consequence of the existence of a few long-range connections, which dominate the original regular structure of the systems and implies each node to become accessible from other nodes after a small number of steps, typically of order logN\ell \propto \log N. However, this effect has been observed in pure-topological networks, where the nodes have no spatial coordinates. In this paper, we present an alalogue of small-world effect observed in real-world transportation networks, where the nodes are embeded in a hree-dimensional space. Using the multidimensional scaling method, we demonstrate how the addition of a few long-range connections can suubstantially reduce the travel time in transportation systems. Also, we investigated the importance of long-range connections when the systems are under an attack process. Our findings are illustrated for two real-world systems, namely the London urban network (streets and underground) and the US highways network enhanced by some of the main US airlines routes

    The simplicity of planar networks

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    Shortest paths are not always simple. In planar networks, they can be very different from those with the smallest number of turns - the simplest paths. The statistical comparison of the lengths of the shortest and simplest paths provides a non trivial and non local information about the spatial organization of these graphs. We define the simplicity index as the average ratio of these lengths and the simplicity profile characterizes the simplicity at different scales. We measure these metrics on artificial (roads, highways, railways) and natural networks (leaves, slime mould, insect wings) and show that there are fundamental differences in the organization of urban and biological systems, related to their function, navigation or distribution: straight lines are organized hierarchically in biological cases, and have random lengths and locations in urban systems. In the case of time evolving networks, the simplicity is able to reveal important structural changes during their evolution.Comment: 8 pages, 4 figure

    On time-varying collaboration networks

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    The patterns of scientific collaboration have been frequently investigated in terms of complex networks without reference to time evolution. In the present work, we derive collaborative networks (from the arXiv repository) parameterized along time. By defining the concept of affine group, we identify several interesting trends in scientific collaboration, including the fact that the average size of the affine groups grows exponentially, while the number of authors increases as a power law. We were therefore able to identify, through extrapolation, the possible date when a single affine group is expected to emerge. Characteristic collaboration patterns were identified for each researcher, and their analysis revealed that larger affine groups tend to be less stable

    Mapping road network communities for guiding disease surveillance and control strategies

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    Human mobility is increasing in its volume, speed and reach, leading to the movement and introduction of pathogens through infected travelers. An understanding of how areas are connected, the strength of these connections and how this translates into disease spread is valuable for planning surveillance and designing control and elimination strategies. While analyses have been undertaken to identify and map connectivity in global air, shipping and migration networks, such analyses have yet to be undertaken on the road networks that carry the vast majority of travellers in low and middle income settings. Here we present methods for identifying road connectivity communities, as well as mapping bridge areas between communities and key linkage routes. We apply these to Africa, and show how many highly-connected communities straddle national borders and when integrating malaria prevalence and population data as an example, the communities change, highlighting regions most strongly connected to areas of high burden. The approaches and results presented provide a flexible tool for supporting the design of disease surveillance and control strategies through mapping areas of high connectivity that form coherent units of intervention and key link routes between communities for targeting surveillance.Comment: 11 pages, 5 figures, research pape

    The human as a resource of the hypermodern organizations: resonances of managerialist power

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    [RESUMEN]El panorama actual laboral se caracteriza por una economía gestionaria, en la cual las consideraciones contables y financieras se sobreponen a las consideraciones humanas y sociales. Hay, con efecto, la creación de un imaginario social dominado por una lógica capitalista y utilitaria. En ese sentido, pretendemos, en este trabajo teórico-reflexivo, aprehender las resonancias del poder e ideología gerencialista para los sujetos insertados en las organizaciones hipermodernas. Para eso, esta investigación ha sido construida bajo la óptica de la Psicosociología, abordaje que enfatiza la dimensión imaginaria, intersubjetiva y grupal de las organizaciones, contribuyendo para la comprensión de las relaciones de trabajo y de la salud mental de los trabajadores.[ABSTRACT]Nowadays, the current work perspective is characterized by a management economy in which the accounting and financial considerations overlap the human and social considerations. Therefore, there is a creation of a social imaginary dominated by a capitalist and utilitarist logic. With this in mind, we intend, in this theoretical-reflexive study, learn the power resonances and managerialist ideology for the included subjects in the hypermodern organizations. This way, this research was constructed by the light of Psichosociology. The reading through these approaches emphasizes the imaginary dimension, intersubjective and group of the organizations, contributing to the understanding of job relations and worker's mental health

    Heteromação e microtrabalho no Brasil

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    No paradigma da heteromação do trabalho, as mudanças operadas pela informatização da economia fazem com que uma massa expressiva de trabalhadores passe a desempenhar atividades essenciais, mas marginais. Objetiva-se, neste estudo, analisar as diferentes formas de microtrabalho heteromatizado remunerado presentes em território nacional, de maneira a lançar luzes compreensivas sobre as condições e especificidades do contexto laboral brasileiro. Para tanto, primeiro foi realizado um levantamento e descrição dos crowdworks de microtarefas em operação no Brasil. Depois, a partir do método netnográfico nos inserimos em 22 grupos de Facebook e de Whatsapp voltados a esse mercado (o que totaliza uma base de cerca de 16 mil perfis registrados) e os acompanhamos durante sete meses. Conclui-se que, no Brasil, há uma importante reserva de mão de obra de microtrabalho e que não estamos diante de um cenário isolado, monolítico e homogêneo. O microtrabalho está imbricado em novas formas de extração de valor da plataformização do trabalho e deve ser compreendido em meio a cadeias de produção mais amplas, globais, onde as condições de trabalho são polissêmicas, assimétricas e regidas mormente por países do Norte global

    A PANDEMIA DE COVID-19 (SARS-CoV-2) E AS CONTRADIÇÕES DO MUNDO DO TRABALHO

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    Pretende-se analisar de que maneira a pandemia de COVID-19 se imbrica a contradições existentes no mundo do trabalho contemporâneo, trazendo-as à tona em um momento de vulnerabilidade coletiva, desencadeada por fraturas sociais e econômicas. Argumenta-se que a compreensão dessas relações traz contribuições à investigação dos impactos psicossociais do COVID-19 em nossa sociedade, bem como pode elucidar caminhos profícuos ao entendimento da dinâmica de sofrimento psíquico relacionado a categorias profissionais que assumem protagonismo no combate à pandemia
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