365 research outputs found

    Nantes vs Shenzhen: Comparison and reflection on the development characteristics of green cities in France and China

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    Under the background that all countries in the world are facing the environmental pollution brought by the industrial revolution, the concept of sustainable development provides a new direction for the economic development of all countries. For cities that are both the center of human activities and the source of environmental pollution, green reform has become a key measure for countries to practice the concept of sustainable development, so green cities came into being. Under the guidance of national policies and in combination with its own characteristics, Nantes of France has successfully completed the transformation of a green city in less than 20 years through the green art transformation of transportation and public space of Shenzhen. China also relies on high technology to continuously reform and innovate in industrial structure, greening, haze control and water control, so as to realize the transformation of green city. The successful green city construction experience of the two cities provides reference for the development of green cities all over the world

    Spectral radius conditions for fractional [a,b][a,b]-covered graphs

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    A graph GG is called fractional [a,b][a,b]-covered if for every edge ee of GG there is a fractional [a,b][a,b]-factor with the indicator function hh such that h(e)=1h(e)=1. In this paper, we provide tight spectral radius conditions for graphs being fractional [a,b][a,b]-covered.Comment: 9 page

    Does the Dirac Cone Exist in Silicene on Metal Substrates?

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    Absence of the Dirac cone due to a strong band hybridization is revealed to be a common feature for epitaxial silicene on metal substrates according to our first-principles calculations for silicene on Ir, Cu, Mg, Au, Pt, Al, and Ag substrates. The destroyed Dirac cone of silicene, however, can be effectively restored with linear or parabolic dispersion by intercalating alkali metal atoms between silicene and the metal substrates, offering an opportunity to study the intriguing properties of silicene without further transfer of silicene from the metal substrates

    Motion-Scenario Decoupling for Rat-Aware Video Position Prediction: Strategy and Benchmark

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    Recently significant progress has been made in human action recognition and behavior prediction using deep learning techniques, leading to improved vision-based semantic understanding. However, there is still a lack of high-quality motion datasets for small bio-robotics, which presents more challenging scenarios for long-term movement prediction and behavior control based on third-person observation. In this study, we introduce RatPose, a bio-robot motion prediction dataset constructed by considering the influence factors of individuals and environments based on predefined annotation rules. To enhance the robustness of motion prediction against these factors, we propose a Dual-stream Motion-Scenario Decoupling (\textit{DMSD}) framework that effectively separates scenario-oriented and motion-oriented features and designs a scenario contrast loss and motion clustering loss for overall training. With such distinctive architecture, the dual-branch feature flow information is interacted and compensated in a decomposition-then-fusion manner. Moreover, we demonstrate significant performance improvements of the proposed \textit{DMSD} framework on different difficulty-level tasks. We also implement long-term discretized trajectory prediction tasks to verify the generalization ability of the proposed dataset.Comment: Rat, Video Position Predictio

    Five-Tiered Route Planner for Multi-AUV Accessing Fixed Nodes in Uncertain Ocean Environments

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    This article introduces a five-tiered route planner for accessing multiple nodes with multiple autonomous underwater vehicles (AUVs) that enables efficient task completion in stochastic ocean environments. First, the pre-planning tier solves the single-AUV routing problem to find the optimal giant route (GR), estimates the number of required AUVs based on GR segmentation, and allocates nodes for each AUV to access. Second, the route planning tier plans individual routes for each AUV. During navigation, the path planning tier provides each AUV with physical paths between any two points, while the actuation tier is responsible for path tracking and obstacle avoidance. Finally, in the stochastic ocean environment, deviations from the initial plan may occur, thus, an auction-based coordination tier drives online task coordination among AUVs in a distributed manner. Simulation experiments are conducted in multiple different scenarios to test the performance of the proposed planner, and the promising results show that the proposed method reduces AUV usage by 7.5% compared with the existing methods. When using the same number of AUVs, the fleet equipped with the proposed planner achieves a 6.2% improvement in average task completion rate

    Silicene Nanomesh

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    Similar to graphene, zero band gap limits the application of silicene in nanoelectronics despite of its high carrier mobility. By using first-principles calculations, we reveal that a band gap is opened in silicene nanomesh (SNM) when the width W of the wall between the neighboring holes is even. The size of the band gap increases with the reduced W and has a simple relation with the ratio of the removed Si atom and the total Si atom numbers of silicene. Quantum transport simulation reveals that the sub-10 nm single-gated SNM field effect transistors show excellent performance at zero temperature but such a performance is greatly degraded at room temperature
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