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513 results on '"Zhang, Qianggong"'

7. Implicitly Defined Layers in Neural Networks

Author

Zhang, Qianggong, Gu, Yanyang, Mateusz, Michalkiewicz, Baktashmotlagh, Mahsa, and Eriksson, Anders

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

In conventional formulations of multilayer feedforward neural networks, the individual layers are customarily defined by explicit functions. In this paper we demonstrate that defining individual layers in a neural network \emph{implicitly} provide much richer representations over the standard explicit one, consequently enabling a vastly broader class of end-to-end trainable architectures. We present a general framework of implicitly defined layers, where much of the theoretical analysis of such layers can be addressed through the implicit function theorem. We also show how implicitly defined layers can be seamlessly incorporated into existing machine learning libraries. In particular with respect to current automatic differentiation techniques for use in backpropagation based training. Finally, we demonstrate the versatility and relevance of our proposed approach on a number of diverse example problems with promising results.

Published
2020

8. SASSE: Scalable and Adaptable 6-DOF Pose Estimation

Author

Le, Huu, Hoang, Tuan, Zhang, Qianggong, Do, Thanh-Toan, Eriksson, Anders, and Milford, Michael

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Visual localization has become a key enabling component of many place recognition and SLAM systems. Contemporary research has primarily focused on improving accuracy and precision-recall type metrics, with relatively little attention paid to a system's absolute storage scaling characteristics, its flexibility to adapt to available computational resources, and its longevity with respect to easily incorporating newly learned or hand-crafted image descriptors. Most significantly, improvement in one of these aspects typically comes at the cost of others: for example, a snapshot-based system that achieves sub-linear storage cost typically provides no metric pose estimation, or, a highly accurate pose estimation technique is often ossified in adapting to recent advances in appearance-invariant features. In this paper, we present a novel 6-DOF localization system that for the first time simultaneously achieves all the three characteristics: significantly sub-linear storage growth, agnosticism to image descriptors, and customizability to available storage and computational resources. The key features of our method are developed based on a novel adaptation of multiple-label learning, together with effective dimensional reduction and learning techniques that enable simple and efficient optimization. We evaluate our system on several large benchmarking datasets and provide detailed comparisons to state-of-the-art systems. The proposed method demonstrates competitive accuracy with existing pose estimation methods while achieving better sub-linear storage scaling, significantly reduced absolute storage requirements, and faster training and deployment speeds.

Published
2019

14. Coresets for Triangulation

Author

Zhang, Qianggong and Chin, Tat-Jun

Subjects
Computer Science - Computational Geometry, Computer Science - Computer Vision and Pattern Recognition
Abstract

Multiple-view triangulation by $\ell_{\infty}$ minimisation has become established in computer vision. State-of-the-art $\ell_{\infty}$ triangulation algorithms exploit the quasiconvexity of the cost function to derive iterative update rules that deliver the global minimum. Such algorithms, however, can be computationally costly for large problem instances that contain many image measurements, e.g., from web-based photo sharing sites or long-term video recordings. In this paper, we prove that $\ell_{\infty}$ triangulation admits a coreset approximation scheme, which seeks small representative subsets of the input data called coresets. A coreset possesses the special property that the error of the $\ell_{\infty}$ solution on the coreset is within known bounds from the global minimum. We establish the necessary mathematical underpinnings of the coreset algorithm, specifically, by enacting the stopping criterion of the algorithm and proving that the resulting coreset gives the desired approximation accuracy. On large-scale triangulation problems, our method provides theoretically sound approximate solutions. Iterated until convergence, our coreset algorithm is also guaranteed to reach the true optimum. On practical datasets, we show that our technique can in fact attain the global minimiser much faster than current methods, Comment: 14 pages for TPAMI summission

Published
2017

25. Surface ozone over the Tibetan Plateau controlled by stratospheric intrusion

Author

Yin, Xiufeng, primary, Rupakheti, Dipesh, additional, Zhang, Guoshuai, additional, Luo, Jiali, additional, Kang, Shichang, additional, de Foy, Benjamin, additional, Yang, Junhua, additional, Ji, Zhenming, additional, Cong, Zhiyuan, additional, Rupakheti, Maheswar, additional, Li, Ping, additional, Hu, Yuling, additional, and Zhang, Qianggong, additional

Published
2023
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26. List of contributors

Author

Bhatta, Rita, primary, Bhattarai, Hemraj, additional, Chen, Pengfei, additional, Cong, Zhiyuan, additional, Dong, Zhiwen, additional, Ghimire, Prakriti Sharma, additional, Gurung, Smriti, additional, Joshi, Rajendra, additional, Kang, Shichang, additional, Li, Chaoliu, additional, Pant, Ramesh Raj, additional, Paudyal, Rukumesh, additional, Qaiser, Faizan Ur Rehman, additional, Qu, Bin, additional, Rai, Santosh K., additional, Ram, Kirpa, additional, Rawat, Bakhat, additional, Regmi, Dikshya, additional, Sharma, Chhatra Mani, additional, Sun, Shiwei, additional, Tripathee, Lekhendra, additional, Wang, Chuanfei, additional, Wang, Xiaoping, additional, Zhang, Qianggong, additional, and Zhang, Yulan, additional

Published
2020
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28. An Efficient Meta-Algorithm for Triangulation

Author

Zhang, Qianggong, Chin, Tat-Jun, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Chen, Chu-Song, editor, Lu, Jiwen, editor, and Ma, Kai-Kuang, editor

Published
2017
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32. Local temperature increases reduce soil microbial residues and carbon stocks

Author

National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities (China), Ministerio de Ciencia e Innovación (España), European Commission, Junta de Andalucía, Zeng, Xiao-Min [0000-0003-4978-1015], Zhang, Qianggong [0000-0002-2189-4248], Delgado-Baquerizo, Manuel [0000-0002-6499-576X], Liu, Yu-Rong [0000-0003-1112-4255], Zeng, Xiao-Min, Feng, Jiao, Yu, Dai-Lin, Wen, Shu-Hai, Zhang, Qianggong, Delgado-Baquerizo, Manuel, Liu, Yu-Rong, National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities (China), Ministerio de Ciencia e Innovación (España), European Commission, Junta de Andalucía, Zeng, Xiao-Min [0000-0003-4978-1015], Zhang, Qianggong [0000-0002-2189-4248], Delgado-Baquerizo, Manuel [0000-0002-6499-576X], Liu, Yu-Rong [0000-0003-1112-4255], Zeng, Xiao-Min, Feng, Jiao, Yu, Dai-Lin, Wen, Shu-Hai, Zhang, Qianggong, Delgado-Baquerizo, Manuel, and Liu, Yu-Rong

Abstract

Warming is known to reduce soil carbon (C) stocks by promoting microbial respiration, which is associated with the decomposition of microbial residue carbon (MRC). However, the relative contribution of MRC to soil organic carbon (SOC) across temperature gradients is poorly understood. Here, we investigated the contribution of MRC to SOC along two independent elevation gradients of our model system (i.e., the Tibetan Plateau and Shennongjia Mountain in China). Our results showed that local temperature increases were negatively correlated with MRC and SOC. Further analyses revealed that rising temperature reduced SOC via decreasing MRC, which helps to explain future reductions in SOC under climate warming. Our findings demonstrate that climate warming has the potential to reduce C sequestration by increasing the decomposition of MRC, exacerbating the positive feedback between rising temperature and CO2 efflux. Our study also considered the influence of multiple environmental factors such as soil pH and moisture, which were more important in controlling SOC than microbial traits such as microbial life-style strategies and metabolic efficiency. Together, our work suggests an important mechanism underlying long-term soil C sequestration, which has important implications for the microbial-mediated C process in the face of global climate change.

Published
2022

33. Microbial assemblies associated with temperature sensitivity of soil respiration along an altitudinal gradient

Author

National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities (China), Hubei Provincial Natural Science Foundation, Chinese Academy of Sciences, Ministerio de Ciencia, Innovación y Universidades (España), Delgado-Baquerizo, Manuel [0000-0002-6499-576X], Zhang, Qianggong [0000-0002-2189-4248], Huang, Qiaoyun [0000-0002-2733-8066], Chen, Ji [0000-0001-7026-6312], Liu, Yu-Rong [0000-0003-1112-4255], Zeng, Xiao-Min, Feng, Jiao, Chen, Ji, Delgado-Baquerizo, Manuel, Zhang, Qianggong, Zhou, Xin-Quan, Yuan, Yusen, Feng, Songhui, Zhang, Kexin, Liu, Yu-Rong, Huang, Qiaoyun, National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities (China), Hubei Provincial Natural Science Foundation, Chinese Academy of Sciences, Ministerio de Ciencia, Innovación y Universidades (España), Delgado-Baquerizo, Manuel [0000-0002-6499-576X], Zhang, Qianggong [0000-0002-2189-4248], Huang, Qiaoyun [0000-0002-2733-8066], Chen, Ji [0000-0001-7026-6312], Liu, Yu-Rong [0000-0003-1112-4255], Zeng, Xiao-Min, Feng, Jiao, Chen, Ji, Delgado-Baquerizo, Manuel, Zhang, Qianggong, Zhou, Xin-Quan, Yuan, Yusen, Feng, Songhui, Zhang, Kexin, Liu, Yu-Rong, and Huang, Qiaoyun

Abstract

Identifying the drivers of the response of soil microbial respiration to warming is integral to accurately forecasting the carbon-climate feedbacks in terrestrial ecosystems. Microorganisms are the fundamental drivers of soil microbial respiration and its response to warming; however, the specific microbial communities and properties involved in the process remain largely undetermined. Here, we identified the associations between microbial community and temperature sensitivity (Q10) of soil microbial respiration in alpine forests along an altitudinal gradient (from 2974 to 3558 m) from the climate-sensitive Tibetan Plateau. Our results showed that changes in microbial community composition accounted for more variations of Q10 values than a wide range of other factors, including soil pH, moisture, substrate quantity and quality, microbial biomass, diversity and enzyme activities. Specifically, co-occurring microbial assemblies (i.e., ecological clusters or modules) targeting labile carbon consumption were negatively correlated with Q10 of soil microbial respiration, whereas microbial assemblies associated with recalcitrant carbon decomposition were positively correlated with Q10 of soil microbial respiration. Furthermore, there were progressive shifts of microbial assemblies from labile to recalcitrant carbon consumption along the altitudinal gradient, supporting relatively high Q10 values in high-altitude regions. Our results provide new insights into the link between changes in major microbial assemblies with different trophic strategies and Q10 of soil microbial respiration along an altitudinal gradient, highlighting that warming could have stronger effects on microbially-mediated soil organic matter decomposition in high-altitude regions than previously thought.

Published
2022

35. Dramatic Carbon Loss in a Permafrost Thaw Slump in the Tibetan Plateau is Dominated by the Loss of Microbial Necromass Carbon

Author

Zhou, Wenting, primary, Ma, Tian, additional, Yin, Xiufeng, additional, Wu, Xiaodong, additional, Li, Quanlian, additional, Rupakheti, Dipesh, additional, Xiong, Xin, additional, Zhang, Qianggong, additional, Mu, Cuicui, additional, de Foy, Benjamin, additional, Rupakheti, Maheswar, additional, Kang, Shichang, additional, and Qin, Dahe, additional

Published
2023
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41. Supplementary material to "Unexpectedly high concentrations of atmospheric mercury species in Lhasa, the largest city on the Tibetan Plateau"

Author

Lin, Huiming, primary, Tong, Yindong, additional, Chen, Long, additional, Yu, Chenghao, additional, Chu, Zhaohan, additional, Zhang, Qianru, additional, Yin, Xiufeng, additional, Zhang, Qianggong, additional, Kang, Shichang, additional, Liu, Junfeng, additional, Schauer, James, additional, Foy, Benjamin de, additional, and Wang, Xuejun, additional

Published
2022
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42. Unexpectedly high concentrations of atmospheric mercury species in Lhasa, the largest city on the Tibetan Plateau

Author

Lin, Huiming, primary, Tong, Yindong, additional, Chen, Long, additional, Yu, Chenghao, additional, Chu, Zhaohan, additional, Zhang, Qianru, additional, Yin, Xiufeng, additional, Zhang, Qianggong, additional, Kang, Shichang, additional, Liu, Junfeng, additional, Schauer, James, additional, Foy, Benjamin de, additional, and Wang, Xuejun, additional

Published
2022
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43. Surface ozone over High-Mountain Asia controlled by stratospheric intrusion

Author

Yin, Xiufeng, primary, Rupakheti, Dipesh, additional, Zhang, Guoshuai, additional, Luo, Jiali, additional, Kang, Shichang, additional, de Foy, Benjamin, additional, Yang, Junhua, additional, Ji, Zhenming, additional, Cong, Zhiyuan, additional, Rupakheti, Maheswar, additional, Li, Ping, additional, and Zhang, Qianggong, additional

Published
2022
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