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151 results on '"Liu, Yundong"'

9. Adaptive adjacent context negotiation network for object detection in remote sensing imagery.

Author

Dong, Yan, Liu, Yundong, Cheng, Yuhua, Gao, Guangshuai, Chen, Kai, and Li, Chunlei

Subjects
DISASTER relief, EMERGENCY management, SPECTRAL imaging, NEGOTIATION, RESOURCE management
Abstract

Accurate localization of objects of interest in remote sensing images (RSIs) is of great significance for object identification, resource management, decision-making and disaster relief response. However, many difficulties, like complex backgrounds, dense target quantities, large-scale variations, and small-scale objects, which make the detection accuracy unsatisfactory. To improve the detection accuracy, we propose an Adaptive Adjacent Context Negotiation Network (A2CN-Net). Firstly, the composite fast Fourier convolution (CFFC) module is given to reduce the information loss of small objects, which is inserted into the backbone network to obtain spectral global context information. Then, the Global Context Information Enhancement (GCIE) module is given to capture and aggregate global spatial features, which is beneficial for locating objects of different scales. Furthermore, to alleviate the aliasing effect caused by the fusion of adjacent feature layers, a novel Adaptive Adjacent Context Negotiation network (A2CN) is given to adaptive integration of multi-level features, which consists of local and adjacent branches, with the local branch adaptively highlighting feature information and the adjacent branch introducing global information at the adjacent level to enhance feature representation. In the meantime, considering the variability in the focus of feature layers in different dimensions, learnable weights are applied to the local and adjacent branches for adaptive feature fusion. Finally, extensive experiments are performed in several available public datasets, including DIOR and DOTA-v1.0. Experimental studies show that A2CN-Net can significantly boost detection performance, with mAP increasing to 74.2% and 79.2%, respectively. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Coupling analysis of social-economic water consumption and its effects on the arid environments in Xinjiang of China based on the water and ecological footprints

Author

Aihua Long, Hao Wang, Mingjiang Deng, Pei Zhang, Liu Yundong, Xiaoya Deng, Yang Hai, and Jie Wang

Subjects
Sustainable development, Ecological footprint, 010504 meteorology & atmospheric sciences, 04 agricultural and veterinary sciences, Management, Monitoring, Policy and Law, Structural basin, 01 natural sciences, Arid, Water resources, Environmental protection, 040103 agronomy & agriculture, Spatial ecology, 0401 agriculture, forestry, and fisheries, Environmental science, Environmental degradation, Water use, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology
Abstract

In arid areas, ecological degradation aroused by over-exploitation of fresh water, expansion of artificial oasis and shrinkage of natural oasis, has drawn attention of many scholars and officials. The water and ecological footprints can be used to quantitatively evaluate the water consumption of social-economic activities and their influence on the eco-environments. In addition, increase of the water footprint indicates the expansion of artificial oasis, and the influence on the natural oasis could be reflected by the variation of the ecological footprint. This study was conducted to answer a scientific question that what is the quantitative relationship between the expansion of the artificial oasis and the degradation of the natural oasis in the arid environments of Xinjiang, China. Thus, based on the social-economic data, water consumption data and meteorological data during 2001–2015, we calculated the water and ecological footprints to express the human-related pressure exerted on the water resources and arid environments in Xinjiang (including 14 prefectures and cities), and explore the relationship between the water and ecological footprints and its mechanism by using the coupling analysis and Granger causality test. The results show that both the water and ecological footprints of Xinjiang increased significantly during 2001–2015, and the increasing rate of the ecological footprint was much faster than that of the water footprint. The coupling degree between the water and ecological footprints was relatively high at the temporal scale and varied at the spatial scale. Among the 14 prefectures and cities examined in Xinjiang, the greater social-economic development (such as in Karamay and Urumqi) was associated with the lower coupling degree between the two footprints. Increases in the water footprint will cause the ecological footprint to increase, such that a 1-unit increase in the consumption of water resources would lead to 2–3 units of ecological degradation. The quantitative relationship between the increases of the water and ecological footprints, together with the intensities of water consumption both in the natural and artificial oases of Tarim River Basin, have approved the fact that the formation and expansion of 1 unit of the artificial oasis would bring about the degradation of 2 units of the natural oasis. These conclusions not only provide a technical basis for sustainable development in Xinjiang, but also offer a theoretical guide and scientific information that could be used in similar arid areas around the world.

Published
2020

48. High sensitivity plasmonic temperature sensor based on a side-polished photonic crystal fiber.

Author

Gao, Zhigang, 高, 治刚, Jing, Xili, äş•, 西利, Liu, Yundong, 刘, äş'东, Chen, Hailiang, 陈, 海良, Li, Shuguang, and 李, ć›™ĺ...‰

Subjects
PHOTONIC crystal fibers, TEMPERATURE sensors, SURFACE plasmon resonance, PLASMONICS, FINITE element method, TEMPERATURE measurements
Abstract

A high sensitivity plasmonic temperature sensor based on a side-polished photonic crystal fiber is proposed in this work. In order to achieve high sensitivity and high stability, the gold layer is coated on the side-polished photonic crystal fiber to support surface plasmon resonance. The mixture of ethanol and chloroform is used as the thermosensitive liquid. The performances of the proposed temperature sensor were investigated by the finite element method (FEM). Simulation results indicate that the sensitivity of the temperature sensor is as high as 7.82 nm/°C. It has good linearity (R 2 = 0.99803), the resolution of 1.1 Ă— 10âˆ'3 °C, and the amplitude sensitivity of 0.1008 °Câˆ'1. In addition, the sizes of the small air hole and polishing depth have little influence on the sensitivity. Therefore, the proposed sensor shows a high structure tolerance. The excellent performance and high structure tolerance of the sensor make it an appropriate choice for temperature measurement. [ABSTRACT FROM AUTHOR]

Published
2022
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