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919 results on '"Yu, Zhiwu"'

3. Multi-View Graph Representation Learning Beyond Homophily

Author

Lin, Bei, Li, You, Gui, Ning, Xu, Zhuopeng, and Yu, Zhiwu

Subjects
Computer Science - Machine Learning, Computer Science - Social and Information Networks
Abstract

Unsupervised graph representation learning(GRL) aims to distill diverse graph information into task-agnostic embeddings without label supervision. Due to a lack of support from labels, recent representation learning methods usually adopt self-supervised learning, and embeddings are learned by solving a handcrafted auxiliary task(so-called pretext task). However, partially due to the irregular non-Euclidean data in graphs, the pretext tasks are generally designed under homophily assumptions and cornered in the low-frequency signals, which results in significant loss of other signals, especially high-frequency signals widespread in graphs with heterophily. Motivated by this limitation, we propose a multi-view perspective and the usage of diverse pretext tasks to capture different signals in graphs into embeddings. A novel framework, denoted as Multi-view Graph Encoder(MVGE), is proposed, and a set of key designs are identified. More specifically, a set of new pretext tasks are designed to encode different types of signals, and a straightforward operation is propxwosed to maintain both the commodity and personalization in both the attribute and the structural levels. Extensive experiments on synthetic and real-world network datasets show that the node representations learned with MVGE achieve significant performance improvements in three different downstream tasks, especially on graphs with heterophily. Source code is available at \url{https://github.com/G-AILab/MVGE}., Comment: 20 pages, 10 figures, accepted by ACM Transaction on Knowledge Discovery in Data

Published
2023

4. Toward mitigating the impact of non-bulk defects on describing water structure in salt aqueous solutions: Characterizing solution density with a network-based structural indicator.

Author

Han, Jiale, Gao, Yitian, Feng, Yixuan, Yu, Zhiwu, Wu, Jian, and Fang, Hongwei

Subjects
MOLECULAR dynamics, SALINE waters, NUMBER concept, GRAPH theory, TEMPERATURE effect
Abstract

Structural indicators, also known as structural descriptors, including order parameters, have been proposed to quantify the structural properties of water to account for its anomalous behaviors. However, these indicators, mainly designed for bulk water, are not naturally transferrable to the vicinity of ions due to disruptions in the immediate neighboring space and a resulting loss of feature completeness. To address these non-bulk defects, we introduced a structural indicator that draws on the concept of clique number from graph theory and the criterion in agglomerative clustering, denoted as the average cluster number. This structural indicator aims to discern intrinsic structural characteristics within the water molecules regardless of the ions occupying the neighboring space, without requiring additional corrections. From molecular dynamics simulation results for neat water and salt aqueous solutions utilizing the TIP4P/2005 water model and the Madrid-2019 force field, we characterized the variations in densities with temperature using this network-based indicator, thereby demonstrating its practical utility. The findings suggest that at lower temperatures, the addition of ions disrupts the intrinsic structure of water molecules, with this effect diminishing as the temperature rises. Cations with larger charge density tend to induce stronger disruptions. This study highlights the importance of mitigating the impact of non-bulk defects before applying the indicators to analyze water's intrinsic structural properties in solutions. By doing so, the relationship between changes in water structure and solution behaviors can be more accurately assessed. [ABSTRACT FROM AUTHOR]

Published
2025
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5. Open-Circuit Fault Detection Method for Full-Bridge Modular Multilevel Converter Sub-Modules

Author

Yu, Zhiwu, Yang, Weiye, Zhang, Pinjia, Zhu, Wenjie, Liu, Bi, Hu, Cungang, Cao, Wenping, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Tan, Kay Chen, Series Editor, Hu, Cungang, editor, and Cao, Wenping, editor

Published
2024
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32. Research on the performance evolution of concrete under the coupling effects of sulfate attack and carbonation

Author

Chen Ying, Liu Peng, Yu Zhiwu, Li Siyang, Hu Cheng, and Lu Dapeng

Subjects
Coupling effect, Sulfate attack, Carbonation, Erosion product, Deterioration mechanism, Performance, Mining engineering. Metallurgy, TN1-997
Abstract

In this study, three coupled modes of coupling effect of sulfate attack and carbonation of concrete were carried out to investigate the change of mass, mechanical properties and apparent morphology. The phase composition, microstructure and morphological characteristics of erosion products were also studied by using environment scanning electron microscope (ESEM-EDS), Fourier infrared spectrometer (FTIR), and X-ray diffraction (XRD). The results indicated that the coupled mode played an obvious effect on the performance and microstructures of specimen due to effects of coupled mode on the deterioration mechanism and erosion products. The surface feature of specimen became worse with carbonation time, and plenty of surface efflorescence and desquamation of products were observed under the coupled mode of carbonation followed by sulfate attack. The relative compressive strength and dynamic elastic modulus of concrete specimen first increased and then decreased with carbonation time, and there existed relationship of a cubic function of single variable between them. The relative mass of concrete specimen increased with the increase of the erosion age of sulfate attack. The difference of the carbonation time per period test played a significant effect on the relative compressive strength and dynamic elastic modulus of concrete specimen, which was due to the dominant effect of carbonation.

Published
2023
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