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1,189 results on '"Liu, Wenqi"'

2. Dynamic supramolecular snub cubes

Author

Wu, Huang, Wang, Yu, Đorđević, Luka, Kundu, Pramita, Bhunia, Surojit, Chen, Aspen X.-Y., Feng, Liang, Shen, Dengke, Liu, Wenqi, Zhang, Long, Song, Bo, Wu, Guangcheng, Liu, Bai-Tong, Yang, Moon Young, Yang, Yong, Stern, Charlotte L., Stupp, Samuel I., Goddard, III, William A., Hu, Wenping, and Stoddart, J. Fraser

Published
2025
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5. Adaptive Event-triggered Control For Strict-feedback Systems With Time-varying Parameters

Author

Tan, Yan, Wu, Liucang, and Liu, Wenqi

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

In this article, we develop a new adaptive event-triggered asymptotic control scheme for strict-feedback systems with fast time-varying parameters. To deal with time-varying parameters with unknown variation boundaries in the feedback path and the input path, we construct three adaptive laws for parameter estimation, two for the uncertain parameters in the feedback path and one for the uncertain parameters in the input path. In particular, two sets of tuning functions are introduced to avoid over-parametrization. Additionally, an event-triggering mechanism is embedded in this adaptive control framework to reduce the data transmission from the controller to the actuator. We also introduce a soft sign function to handle the perturbations caused by sampling errors to achieve asymptotic stability and avoid the so-called parameter drift. The stability analysis shows that the closed-loop system is globally uniformly asymptotically stable and the Zeno behavior can be excluded. Simulation results verify the effectiveness and performance of the proposed adaptive scheme., Comment: 9 pages, 6 figures

Published
2023

6. A combining earthquake forecasting model between deep learning and Epidemic-Type Aftershock Sequence (ETAS) model

Author

Zhang, Haoyuan, Ke, Shuya, Liu, Wenqi, and Zhang, Yongwen

Subjects
Physics - Geophysics
Abstract

The scientific process of earthquake forecasting involves estimating the probability and intensity of earthquakes in a specific area within a certain timeframe, based on seismic activity laws and observational data. Epidemic-Type Aftershock Sequence (ETAS) models, which rely on seismic empirical laws, is one of the most commonly used methods for earthquake forecasting. However, it underestimates feature in short-term time scale and overestimates in long-term time scale. Convolutional Long Short-Term Memory (ConvLSTM), has emerged as a promising approach capable of extracting spatio-temporal features. Hence, we propose a novel composite model named CL-ETAS model, which combines the strengths of ConvLSTM and ETAS model. We conduct experimental verification on real seismic data in Southern California. Our results show that CL-ETAS model outperforms both ETAS model and ConvLstm in accurately forecasting the number of earthquake events, their magnitude, and spatial distribution. Additionally, CL-ETAS model demonstrates notable enhancements in forecast stability and interpretability. These results offer valuable insights and recommendations for future earthquake forecasting endeavors.

Published
2023

16. Research progress on airfoil icing characteristics and complex flowfield analysis

Author

LIU Xiang, LIU Wenqi, ZHAO Liang, RU Jiaxing, WEI Hongsen, and ZHANG Ailing

Subjects
icing, airfoil, separation flow, turbulent flow, numerical simulation, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

The theory of aircraft icing and its disaster mechanisms are crucial for preventing icing accidents and enhancing flight performance. The research progress on the flow field characteristics under different icing conditions and special wing configurations are systematically summarized in this paper. It is pointed out that, the actual three-dimensional ice shapes are complex, have multiple structural features, and coupling mechanisms with separated flow and turbulence structures should be further studied. The aerodynamic performance analysis of special wings under supercooled large droplet conditions is the significant future research direction. Turbulence field analysis focuses on identifying instability characteristics of the icing wing flow field and multi-scale structural interaction mechanisms. Exploring the ice-flow coupling mechanism is of reference value for developing multi-factor, multi-parameter, and multi-scale icing prediction and computational models.

Published
2024
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