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139 results on '"He, Zhidong"'

2. Research on Clarification Question Recognition and Generation in Intelligent Q&A

Author

Hou, Juncheng, Du, Wen, Mu, Qing, Zhang, Kunpeng, He, Zhidong, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Zhang, Min, editor, Xu, Bin, editor, Hu, Fuyuan, editor, Lin, Junyu, editor, Song, Xianhua, editor, and Lu, Zeguang, editor

Published
2024
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4. Heterogeneity induced localization of traffic congestion on networks

Author

He, Zhidong

Subjects
Physics - Physics and Society
Abstract

The emergence of congestion is a critical phenomenon in transport systems. Transport is organized along pathways abstracted by links, which connect different nodes as regions to form the network. The modeling of traffic has so far mainly been based on one-dimensional lattices or networked queuing systems, which restricts mechanistic insights and analytical tractability for traffic dynamics on general networks. An interpretable kinetics model is necessary for understanding the impact of the network structure on traffic congestion in large-scale networks. Considering a generalized flow-density relation within each node, we propose and investigate a general traffic model on networks with external injections and exits. We observe various phases in terms of node density that exhibit distinct behaviors under different injection rates. The onset of congestion along with the coexistence of free nodes and congested nodes, manifested by the spatial localization of traffic congestion, is induced by the asymmetry of the flow transitions between neighbors in the network. The proposed congestion centrality allows us to determine the congestion threshold, identify congested nodes and predict congestion propagation. Our model and results are shown to cover a broad spectrum of implications for transport dynamics on networks as well as offer a practical prospect for traffic optimizations such as congestion alleviation and targeted diffusion.

Published
2023

6. Inversion of Mangrove Canopy Leaf Functional Traits on the Qi'ao Island Based on UAV Hyperspectral Remote Sensing

Author

Wang Meng, Sun Zhengzheng, He Zhidong, Wang Zhihui, Geng Shoubao, Zhao Xinfeng, Yang Long, and Sun Zhongyu

Subjects
leaf functional traits, uav hyperspectral remote sensing, functional trait mapping, plsr, mangrove forest, qi'ao island, Geography (General), G1-922
Abstract

Quantitative studies of mangrove leaf functional traits will help us understand the adaptive evolutionary strategies of mangrove plants and the relationship between mangrove biodiversity and ecosystem functions. Because of the special environment of the intertidal zone where mangroves are located, it is very difficult to obtain the functional traits of mangrove canopies from the ground, and relevant studies are lacking. The maturity of Unmanned Aerial Vehicle (UAV) hyperspectral remote sensing technology provides a new means of conducting such research. This study considered mangroves on Qi'ao Island, Zhuhai, as the research object. Based on UAV hyperspectral data, two UAV hyperspectral data processing methods, which combined Partial Least Squares Regression with Normalized Difference Vegetation Index (PLSR+NDVI) and Partial Least Squares Regression with Continuous Wavelet Transform (PLSR+CWT), were used to estimate the 10 canopy leaf functional traits of mangroves on Qi'ao Island. The results showed that the PLSR + NDVI method was more suitable for the inversion of mangrove canopy-specific leaf weight (LMA), phosphorus content per unit mass (Pmass), and nitrogen content per unit area (Narea), whereas the PLSR + CWT method was more suitable for the estimation of the nitrogen/phosphorus ratio (N/P), chlorophyll content (Cab), and carotenoid content (Cxc). However, the results of the above two methods for retrieving the nitrogen content per unit mass (Nmass), potassium content per unit mass (Kmass), phosphorus content per unit area (Parea), and potassium content per unit area (Karea) were not ideal (R2

Published
2023
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7. MMpedia: A Large-Scale Multi-modal Knowledge Graph

Author

Wu, Yinan, Wu, Xiaowei, Li, Junwen, Zhang, Yue, Wang, Haofen, Du, Wen, He, Zhidong, Liu, Jingping, Ruan, Tong, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Payne, Terry R., editor, Presutti, Valentina, editor, Qi, Guilin, editor, Poveda-Villalón, María, editor, Stoilos, Giorgos, editor, Hollink, Laura, editor, Kaoudi, Zoi, editor, Cheng, Gong, editor, and Li, Juanzi, editor

Published
2023
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10. Optimization of convergence rate via algebraic connectivity

Author

He, Zhidong

Subjects
Mathematics - Optimization and Control, Electrical Engineering and Systems Science - Systems and Control
Abstract

The algebraic connectivity of a network characterizes the lower-bound of the exponential convergence rate of consensus processes. This paper investigates the problem of accelerating the convergence of consensus processes by adding links to the network. Based on a perturbation formula of the algebraic connectivity, we propose a greedy strategy for undirected networks and give a lower bound of its performance through an approximation of submodularity. We further extend our investigation to directed networks, where the second smallest real part among all the eigenvalues of the non-Hermitian Laplacian matrix, i.e., the generalized algebraic connectivity, indicates the expected convergence rate. We propose the metrics to evaluate the impact of an adding subgraph on the generalized algebraic connectivity, and apply a modified greedy strategy to optimize the generalized algebraic connectivity. Numerical results in empirical networks exhibit that our proposed methods outperform some other methods based on traditional topological metrics. Our research also verifies the dramatic differences between the optimization in undirected networks and that in directed networks., Comment: 10 pages, 4 figures

Published
2019

22. Estimation of water quality variables based on machine learning model and cluster analysis-based empirical model using multi-source remote sensing data in inland reservoirs, South China

Author

Tian, Di, primary, Zhao, Xinfeng, additional, Gao, Lei, additional, Liang, Zuobing, additional, Yang, Zaizhi, additional, Zhang, Pengcheng, additional, Wu, Qirui, additional, Ren, Kun, additional, Li, Rui, additional, Yang, Chenchen, additional, Li, Shaoheng, additional, Wang, Meng, additional, He, Zhidong, additional, Zhang, Zebin, additional, and Chen, Jianyao, additional

Published
2023
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27. Recovering Power Grids Using Strategies Based on Network Metrics and Greedy Algorithms

Author

Wang, F. (author), Cetinay, Hale (author), He, Zhidong (author), Liu, L. (author), Van Mieghem, P.F.A. (author), Kooij, Robert (author), Wang, F. (author), Cetinay, Hale (author), He, Zhidong (author), Liu, L. (author), Van Mieghem, P.F.A. (author), and Kooij, Robert (author)

Abstract

For this study, we investigated efficient strategies for the recovery of individual links in power grids governed by the direct current (DC) power flow model, under random link failures. Our primary objective was to explore the efficacy of recovering failed links based solely on topological network metrics. In total, we considered 13 recovery strategies, which encompassed 2 strategies based on link centrality values (link betweenness and link flow betweenness), 8 strategies based on the products of node centrality values at link endpoints (degree, eigenvector, weighted eigenvector, closeness, electrical closeness, weighted electrical closeness, zeta vector, and weighted zeta vector), and 2 heuristic strategies (greedy recovery and two-step greedy recovery), in addition to the random recovery strategy. To evaluate the performance of these proposed strategies, we conducted simulations on three distinct power systems: the IEEE 30, IEEE 39, and IEEE 118 systems. Our findings revealed several key insights: Firstly, there were notable variations in the performance of the recovery strategies based on topological network metrics across different power systems. Secondly, all such strategies exhibited inferior performance when compared to the heuristic recovery strategies. Thirdly, the two-step greedy recovery strategy consistently outperformed the others, with the greedy recovery strategy ranking second. Based on our results, we conclude that relying solely on a single metric for the development of a recovery strategy is insufficient when restoring power grids following link failures. By comparison, recovery strategies employing greedy algorithms prove to be more effective choices., Network Architectures and Services, Intelligent Electrical Power Grids, Quantum & Computer Engineering

Published
2023
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33. Ageing induces tissue-specific transcriptomic changes in Caenorhabditis elegans

Author

Wang, Xueqing, Jiang, Quanlong, Song, Yuanyuan, He, Zhidong, Zhang, Hongdao, Song, Mengjiao, Zhang, Xiaona, Dai, Yumin, Karalay, Oezlem, Dieterich, Christoph, Antebi, Adam, Wu, Ligang, Han, Jing-Dong J., Shen, Yidong, Wang, Xueqing, Jiang, Quanlong, Song, Yuanyuan, He, Zhidong, Zhang, Hongdao, Song, Mengjiao, Zhang, Xiaona, Dai, Yumin, Karalay, Oezlem, Dieterich, Christoph, Antebi, Adam, Wu, Ligang, Han, Jing-Dong J., and Shen, Yidong

Abstract

Ageing is a complex process with common and distinct features across tissues. Unveiling the underlying processes driving ageing in individual tissues is indispensable to decipher the mechanisms of organismal longevity. Caenorhabditis elegans is a well-established model organism that has spearheaded ageing research with the discovery of numerous genetic pathways controlling its lifespan. However, it remains challenging to dissect the ageing of worm tissues due to the limited description of tissue pathology and access to tissue-specific molecular changes during ageing. In this study, we isolated cells from five major tissues in young and old worms and profiled the age-induced transcriptomic changes within these tissues. We observed a striking diversity of ageing across tissues and identified different sets of longevity regulators therein. In addition, we found novel tissue-specific factors, including irx-1 and myrf-2, which control the integrity of the intestinal barrier and sarcomere structure during ageing respectively. This study demonstrates the complexity of ageing across worm tissues and highlights the power of tissue-specific transcriptomic profiling during ageing, which can serve as a resource to the field.

Published
2022

36. Ageing induces tissue‐specific transcriptomic changes in Caenorhabditis elegans

Author

Wang, Xueqing, primary, Jiang, Quanlong, additional, Song, Yuanyuan, additional, He, Zhidong, additional, Zhang, Hongdao, additional, Song, Mengjiao, additional, Zhang, Xiaona, additional, Dai, Yumin, additional, Karalay, Oezlem, additional, Dieterich, Christoph, additional, Antebi, Adam, additional, Wu, Ligang, additional, Han, Jing‐Dong J, additional, and Shen, Yidong, additional

Published
2022
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37. Visualizing Emergent Magnetic Flux of Antiskyrmions in Mn1.4PtSn Magnet.

Author

He, Zhidong, Song, Dongsheng, Wang, Weiwei, Wang, Ning, Ge, Binghui, Wang, Shouguo, Tian, Mingliang, and Du, Haifeng

Subjects
*MAGNETIC flux, *MAGNETS, *ELECTRON holography, *MAGNETIC fields, *SYMMETRY breaking, *MAGNETIC structure, *SKYRMIONS
Abstract

Topologically protected spin textures, such as magnetic skyrmions, have attracted considerable attention owing to their emergent electromagnetic phenomena and potential applications in spintronics. The antiskyrmion, a new member of the skyrmion family in the nanoscale dimension, consists of alternating Néel‐ and Bloch‐type boundary walls; it has already been discovered in non‐centrosymmetric magnets with D2d/S4 symmetry. However, its complex spin textures and unique magnetic‐charge‐induced emergent field have not been explicitly visualized thus far. Here, state‐of‐the‐art off‐axis electron holography is employed to directly resolve the antiskyrmions in a non‐centrosymmetric Heusler magnet Mn1.4PtSn with D2d symmetry. The magnetic flux distribution inside and outside the antiskyrmion is clearly imaged, indicating the emergent magnetic field induced by the broken cylindrical symmetry. More importantly, the closed emergent flux between adjacent antiskyrmions is revealed, indicating the antiskyrmion‐antiskyrmion interactions (a different mechanism compared to that of conventional skyrmions). These findings provide a clear and deep insight into the intrinsic magnetic flux configuration in the antiskyrmion‐hosted magnets, thus paving the way for the manipulation of antiskyrmions in the future. [ABSTRACT FROM AUTHOR]

Published
2022
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