1,456 research outputs found

    Predicting and understanding spatio-temporal dynamics of species recovery : implications for Asian crested ibis Nipponia nippon conservation in China

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    Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 31372218) and cofunded by the China Scholarship Council (CSC) and the ITC Research Fund, Enschede, the Netherlands. We thank Shaanxi Hanzhong Crested Ibis National Nature Reserve for sharing the data of nest site locations. We are grateful to Brendan Wintle, Justin Travis and two anonymous reviewers for helpful comments on a previous version of the manuscript.Peer reviewedPublisher PD

    TD-Net: A Tri-domain network for sparse-view CT reconstruction

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    Sparse-view CT reconstruction, aimed at reducing X-ray radiation risks, frequently suffers from image quality degradation, manifested as noise and artifacts. Existing post-processing and dual-domain techniques, although effective in radiation reduction, often lead to over-smoothed results, compromising diagnostic clarity. Addressing this, we introduce TD-Net, a pioneering tri-domain approach that unifies sinogram, image, and frequency domain optimizations. By incorporating Frequency Supervision Module(FSM), TD-Net adeptly preserves intricate details, overcoming the prevalent over-smoothing issue. Extensive evaluations demonstrate TD-Net's superior performance in reconstructing high-quality CT images from sparse views, efficiently balancing radiation safety and image fidelity. The enhanced capabilities of TD-Net in varied noise scenarios highlight its potential as a breakthrough in medical imaging

    Domain Decomposition for Stokes-Darcy Flows with Curved Interfaces

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    AbstractA non-overlapping domain decomposition method is developed for coupled Stokes-Darcy flows in irregular domains. The Stokes region is discretized by standard Stokes finite elements while the Darcy region is discretized by the multipoint flux mixed finite element method. The subdomain grids may not match on the interfaces and mortar finite elements are employed to impose weakly interface continuity conditions. The interfaces can be curved and matching conditions are imposed via appropriate mappings from physical grids to reference grids with flat interfaces. The global problem is reduced to a mortar interface problem, which is solved by the conjugate gradient method. Each iteration involves solving subdomain problems of either Stokes or Darcy type, which is done in parallel. Computational experiments are presented to illustrate the convergence of the discretization and the condition number of the interface operator

    Upravljanje aktivnom snagom regenerativnog kaskadnog invertera uz smanjenje izmjenične komponente snage u istosmjernom međukrugu

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    This paper presents a regenerative cascade inverter topology with direct active power control scheme. From the mathematical model of the proposed regenerative cascade inverter, the instantaneous active power and reactive power are derived. Based on the instantaneous \u27abc\u27 theory, direct active power feed-forward control is proposed to reduce AC power and voltage fluctuation in DC link. Moreover, a load current full order observer is established to avoid the inconvenient of the current sensor installation. The proposed control scheme is analyzed theoretically by simulation, and verified experimentally.U ovome radu predstavljena je topologija regenerativnog kaskadnog invertera sa shemom direktnog upravljanja aktivnom snagom. Trenutna aktivna i reaktivna snaga dobiveni su iz matematičkog modela predloženog regenerativnog kaskadnog invertera. Na temelju \u27abc\u27 teorije, predloženo je unaprijedno upravljanje aktivnom snagom kako bi se smanjila izmjenična komponenta snage i promjena napona u istosmjernom međukrugu. Ugradnja senzora za mjerenje struje izbjegla se razvijanjem observera punog reda. Predložena shema upravljanja testirana je simulacijski i eksperimentalno
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