229 research outputs found

    Segmentation of networks from VHR remote sensing images using a directed phase field HOAC model.

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    We propose a new algorithm for network segmentation from very high resolution (VHR) remote sensing images. The algorithm performs this task quasi-automatically, that is, with no human intervention except to fix some parameters. The task is made difficult by the amount of prior knowledge about network region geometry needed to perform the task, knowledge that is usually provided by a human being. To include such prior knowledge, we make use of methodological advances in region modelling: a phase field higher-order active contour of directed networks is used as the prior model for region geometry. By adjoining an approximately conserved flow to a phase field model encouraging network shapes (i.e. regions composed of branches meeting at junctions), the model favours network regions in which different branches may have very different widths, but in which width change along a branch is slow; in which branches do not come to an end, hence tending to close gaps in the network; and in which junctions show approximate 'conservation of width'. We also introduce image models for network and background, which are validated using maximum likelihood segmentation against other possibilities. We then test the full model on VHR optical and multispectral satellite images

    Inflection point model under phase field higher-order active contours for network extraction from VHR satellite images

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    The segmentation of networks is important in several imaging domains, and models incorporating prior shape knowledge are often essential for the automatic performance of this task. We incorporate such knowledge via phase fields and higher-order active contours (HOACs). In this paper: we introduce an improved prior model, the phase field HOAC `inflection point' model of a network; we present an improved data term for the segmentation of road networks; we confirm the robustness of the resulting model to choice of gradient descent initialization; and we illustrate these points via road network extraction results on VHR satellite images

    Phase diagram of a long bar under a higher-order active contour energy: application to hydrographic network extraction from VHR satellite images

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    The segmentation of networks is important in several imaging domains, and models incorporating prior shape knowledge are often essential for the automatic performance of this task. Higher-order active contours provide a way to include such knowledge, but their behaviour can vary significantly with parameter values: e.g. the same energy can model networks or a dasiagas of circlespsila. In this paper, we present a stability analysis of a HOAC energy leading to the phase diagram of a long bar. The results, which are confirmed by numerical experiments, enable the selection of parameter values for the modelling of network shapes using the energy. We apply the resulting model to the problem of hydrographic network extraction from VHR satellite images

    Retraction of chaotic manifolds and fractal

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    In this article we will describe some types of retractions of chaotic manifold. We also will introduce a definition for the fractional dimension of the chaotic manifold. Some theorems related to them will be obtained. Some applications will also be mentioned in this paper

    The impact of changes in stakeholder salience on CSR activities in Russian energy firms: a contribution to the divergence / convergence debate

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    This empirical paper examines the drivers underpinning changes to socially-responsible behaviours in the Russian energy sector. Responding to recent requests to contextualise CSR research, we focus on the changing set of stakeholders and developments in their saliency as reflected in corporations’ CSR activities. Based on interviews with more than thirty industry professionals, our findings suggest that Russian energy companies’ CSR is strongly stakeholder driven, and organisations adapt their activities according to their dependence on the resources that these salient stakeholders possess. We challenge the proposition that CSR in Russia arises from purely endogenous, historical, paternalism or neo-paternalism. We identify stakeholders that now shape CSR in the Russian energy sector, both endogenous (institutional and contextual forces relevant to the national business system) and exogenous (relating to the organisational field of the energy industry - international by nature). We thereby contribute to the convergence / divergence debate within CSR theory by demonstrating that both national business systems and the organisational field must be taken into account when analysing the forces that shape CSR strategies in any one country

    Business groups and corporate responsibility for the public good

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    This paper analyses the relationship between Business Groups as a distinct way of organizing economic activities and their relation to the public good. We first analyze the phenomenon of Business Groups and discuss some of their core features. Subsequently, the paper moves to analyzing the existing literature on Business Groups and Corporate Social Responsibility (CSR) as the most common label for the topic of this Special Issue. Subsequently, specific peculiarities of Business Groups in the context of CSR and their contribution to the public good are fleshed out. Based on this analysis, the paper delineates some implications for the field of CSR and the wider debate on the nature of the firm. We close with some perspectives for future research

    Modularity and predicted functions of the global sponge-microbiome network

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    Defining the organisation of species interaction networks and unveiling the processes behind their assembly is fundamental to understanding patterns of biodiversity, community stability and ecosystem functioning. Marine sponges host complex communities of microorganisms that contribute to their health and survival, yet the mechanisms behind microbiome assembly are largely unknown. We present the global marine sponge-microbiome network and reveal a modular organisation in both community structure and function. Modules are linked by a few sponge species that share microbes with other species around the world. Further, we provide evidence that abiotic factors influence the structuring of the sponge microbiome when considering all microbes present, but biotic interactions drive the assembly of more intimately associated 'core' microorganisms. These findings suggest that both ecological and evolutionary processes are at play in host-microbe network assembly. We expect mechanisms behind microbiome assembly to be consistent across multicellular hosts throughout the tree of life
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