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arXiv 2022年

作者： Xing, Wei W. Zhang, Ziyang Shah, Akeel A. Key Laboratory of Low-grade Energy Utilisation Technologies and Systems MOE Chongqing University Chongqing400030 China School of Mathematics and Statistics University of Sheffield Hounsfield Road SheffieldS3 7RH United Kingdom College of Computer Science and Software Engineering Shenzhen University Shenzhen518060 China

Predicting the end-of-life or remaining useful life of batteries in electric vehicles is a critical and challenging problem, predominantly approached in recent years using machine learning to predict the evolution of the state-of-health during repeated cycling. To improve the accuracy of predictive estimates, especially early in the battery lifetime, a number of algorithms have incorporated features that are available from data collected by battery management systems. Unless multiple battery data sets are used for a direct prediction of the end-of-life, which is useful for ball-park estimates, such an approach is infeasible since the features are not known for future cycles. In this paper, we develop a highly-accurate method that can overcome this limitation, by using a modified Gaussian process dynamical model (GPDM). We introduce a kernelised version of GPDM for a more expressive covariance structure between both the observable and latent coordinates. We combine the approach with transfer learning to track the future state-of-health up to end-of-life. The method can incorporate features as different physical observables, without requiring their values beyond the time up to which data is available. Transfer learning is used to improve learning of the hyperparameters using data from similar batteries. The accuracy and superiority of the approach over modern benchmarks algorithms including a Gaussian process model and deep convolutional and recurrent networks is demonstrated on three data sets, particularly at the early stages of battery lifetime. Copyright © 2022, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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An integrated framework for accelerating reactive flow simulation using GPU and machine learning models

arXiv

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arXiv 2023年

作者： Mao, Runze Wang, Yingrui Zhang, Min Li, Han Xu, Jiayang Dong, Xinyu Zhang, Yan Chen, Zhi X. State Key Laboratory of Turbulence and Complex Systems Aeronautics and Astronautics College of Engineering Peking University Beijing100871 China Beijing100080 China Shanghai SenseTime Intelligent Technology Co. LTD Shanghai200233 China CAEP Software Center for High Performance Numerical Simulation Beijing100088 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

Recent progress in artificial intelligence (AI) and high-performance computing (HPC) have brought potentially game-changing opportunities in accelerating reactive flow simulations. In this study, we introduce an open-source computational fluid dynamics (CFD) framework that integrates the strengths of machine learning (ML) and graphics processing unit (GPU) to demonstrate their combined capability. Within this framework, all computational operations are solely executed on GPU, including ML-accelerated chemistry integration, fully-implicit solving of PDEs, and computation of thermal and transport properties, thereby eliminating the CPU-GPU memory copy overhead. Optimisations both within the kernel functions and during the kernel launch process are conducted to enhance computational performance. Strategies such as static data reorganisation and dynamic data allocation are adopted to reduce the GPU memory footprint. The computational performance is evaluated in two turbulent flame benchmarks using quasi-DNS and LES modelling, respectively. Remarkably, while maintaining a similar level of accuracy to the conventional CPU/CVODE-based solver, the GPU/ML-accelerated approach shows an overall speedup of over two orders of magnitude for both cases. This result highlights that high-fidelity turbulent combustion simulation with finite-rate chemistry that requires normally hundreds of CPUs can now be performed on portable devices such as laptops with a medium-end GPU. © 2023, CC BY.

关键词： Graphics processing unit

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A Survey on epistemic (model) uncertainty in supervised learning: Recent advances and applications

arXiv

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arXiv 2021年

作者： Zhou, Xinlei Liu, Han Pourpanah, Farhad Zeng, Tieyong Wang, Xizhao College of Computer Science and Software Engineering Shenzhen University Shenzhen518060 China Guangdong Key Laboratory of Intelligent Information Processing Shenzhen University 518060 China College of Mathematics and Statistics Shenzhen University Shenzhen518060 China Department of Mathematics Chinese University of Hong Kong Hong Kong

Quantifying the uncertainty of supervised learning models plays an important role in making more reliable predictions. Epistemic uncertainty, which usually is due to insufficient knowledge about the model, can be reduced by collecting more data or refining the learning models. Over the last few years, scholars have proposed many epistemic uncertainty handling techniques which can be roughly grouped into two categories, i.e., Bayesian and ensemble. This paper provides a comprehensive review of epistemic uncertainty learning techniques in supervised learning over the last five years. As such, we, first, decompose the epistemic uncertainty into bias and variance terms. Then, a hierarchical categorization of epistemic uncertainty learning techniques along with their representative models is introduced. In addition, several applications such as computer vision (CV) and natural language processing (NLP) are presented, followed by a discussion on research gaps and possible future research directions. Copyright © 2021, The Authors. All rights reserved.

关键词： Uncertainty analysis

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Theoretical and Experimental Investigation of On-Chip Mid-Infrared Chalcogenide Waveguide Ch4 Sensor Based on Wavelength Modulation Spectroscopy

SSRN

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SSRN 2022年

作者： Pi, Mingquan Huang, Yijun Zhao, Huan Peng, Zihang Lang, Jiaming Ji, Jialin Teng, Ling Song, Fang Liang, Lei Zhang, Yu Zheng, Chuantao Wang, Yiding Tittel, Frank K. State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin University 2699 Qianjin Street Changchun130012 China School of Mathematics and Statistics Changchun University of Science and Technology Changchun130022 China State Key Laboratory of Luminescence and Applications Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun130033 China Department of Electrical and Computer Engineering Rice University 6100 Main Street HoustonTX77005 United States

Compared with direct absorption spectroscopy (DAS), wavelength modulation spectroscopy (WMS) with good ability of suppressing noise is rarely used in waveguide sensor. The influence of waveguide parameters on WMS sensing performance is required to clarify in both theory and experiment. Three mid-infrared waveguide methane (CH4) sensors (trapezoid, rectangular, suspended) were proposed and optimized for WMS simulation. Theoretical formulation and the experimental sensing noise were used to numerically evaluate the key figure of merit more accurately. Simulation results were presented to show the influence of waveguide parameters on sensing performance. Two chalcogenide on magnesium fluoride (ChG-on-MgF2) trapezoid waveguide sensors were fabricated using lift-off method, and CH4 measurement was carried out using WMS. The waveguide loss was measured to be 1.57 dB/cm, leading to an optimal sensor length of 2.7 cm. The limit of detection (LoD) for the 1cm- and 2cm-long waveguide sensors are 0.68% and 0.17% with an averaging time of 0.2 s. The experimentally achieved second harmonic (2f) signal amplitude and LoD show good agreement with the theoretical results, verifying the feasibility of the design and analysis model of the WMS-based waveguide sensor. Due to the use of WMS and a reduction of waveguide loss from 3.6 to 1.57 dB/cm, the LoD of the 2cm-long ChG-on-MgF2 sensor is 24 times lower than our previously reported 2cm-long ChG-on-SiO2 sensor based on DAS. This work provides a systematic guidance for the design of waveguide gas sensor based on WMS and contributes to improving the sensitivity of on-chip gas sensing. © 2022, The Authors. All rights reserved.

关键词： Chalcogenides

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Bulky-Polymethylpentene Inscription Using Shg Femtosecond Laser Beams with Angular Momentums

SSRN

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SSRN 2023年

作者： Zhu, Guangyu Wang, Xi-Yuan Zheng, Si-Yang Wang, Xin-Zhu Chen, Kai Dong, Shu-Yi Xu, Linji Li, Peng Chen, Xi-Hao Ju, An-Qi Ahuir-Torres, Juan Ignacio College of Physics Chongqing University Chongqing400044 China School of Electronic Information and Electrical Engineering Chongqing University of Arts and Sciences Chongqing402160 China College of Aerospace Engineering Chongqing University Chongqing400044 China College of Optoelectronic Engineering Chongqing University Chongqing400040 China College of Mathematics and Statistics Chongqing University Chongqing400040 China General Engineering Research Institute Faculty of Engineering and Technology Liverpool John Moores University LiverpoolL3 3AF United Kingdom State Key Laboratory for Modification of Chemical Fibres and Polymer Materials Donghua University Shanghai201620 China Faculty of Engineering Architecture and Information Technology The University of Queensland BrisbaneQLD4072 Australia

Thermoplastic polymer, poly methyl pentene (PMP), has been investigated for laser inscription. Near-ultraviolet (NUV) laser beam was generated by using second harmonic method (SHG) and focused by using lenses with numerical aperture (NA) in the range 0.08 - 0.7. A spatial light modulator addressed with computer-generated holograms created helical wavefronts carrying orbital angular momentum (OAM) at 775nm. Conservation of OAM during the SHG conversion is demonstrated. Using an advanced spectrometer to supercontinuum (SC) signal, it is observed that the integration of photonic energy in Anti-Stokes region is scale linearly with OAM. Laser beam carrying OAM is also investigated with spin angular momentum (SAM) . With high states of OAM, complex filamentary structures converging to the focus are observed which collapse to multiple filaments, in accord with theoretical expectations. Less coupling between two modes of AM in filamentation (FL) was observed in NA > 0.1 region. Linear polarization effect is clearly due to components of the strong third order susceptibility $\chi^{(3)}$ which is for the first time in PMP. Using lenses with NA>0.4. Spiral structure accompanied with rotation sense of optical vortex are constructed, suggesting that chirality structure was formalized in exposure zone. By using longitudinal inscription, tubular structures accompanied with waveguide efect can be constructed in bulky polymer. © 2023, The Authors. All rights reserved.

关键词： Laser beams

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Enhancing crop production in the Haihe Basin while addressing challenges related to water quantity and quality

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Science of the Total Environment 2024年 955卷 176800页

作者： Wang, Gang Yang, Jing Liu, Xia Zhang, Haodi Xu, Xiangbo Luo, Jiafa Bai, Zhaohai Ma, Lin Key Laboratory of Agricultural Water Resources Hebei Key Laboratory of Soil Ecology Center for Agricultural Resources Research Institute of Genetic and Developmental Biology The Chinese Academy of Sciences 286 Huaizhong Road Hebei Shijiazhuang050021 China University of Chinese Academy of Science 19 A Yuquan Road Shijingshan District Beijing100049 China School of Mathematics and Science Hebei GEO University 136 Huai'an Road Hebei Shijiazhuang050031 China College of Computer Science and Software Engineering Shenzhen University China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China AgResearch Limited Ruakura Research Centre Private Bag 3123 Hamilton New Zealand State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Jiangsu Nanjing210023 China

To tackle the challenge of ensuring food security while managing water availability and quality constraints in the Haihe Basin, a critical grain-producing region in China with a dense population and severe water degradation issues, we have developed a comprehensive spatial optimization (CSO) strategy. This approach integrates various crop and soil management practices, land consolidation, and cutting-edge breeding technologies. It also uses a spatial planning model based on linear programming, considering water quantity and quality constraints. Our research shows that crop yields may drop by 14 % (3780 Kt) compared to levels in 2017 due to restrictions on groundwater extraction and nitrogen (N) concentrations in leaching or runoff. However, by strategically maximizing overall crop yields through the integrated CSO strategy without changing the crop production structure, the total crop yield could potentially increase by 81 % (21,817 Kt) while using 3.0 % (86 Kha) less cultivated land than in 2017. This would help to fulfill the projected food demand in 2050. If the integrated aims to minimize the sown area after fulfilling the demand for crops in 2050, around 28 % of the sown area, or 820 Kha cropland, could be reduced compared with 2017. This reduction may save more land for natural conversation. Furthermore, total N losses, including ammonia, nitrous oxide emissions, runoff, and leaching, could be reduced by 23 %–43 % (139–252 Kt), depending on the specific optimization strategy goals. The stepwise integrated optimization strategy provides a feasible framework for the Haihe Basin, enabling the maintenance or even enhancing current crop yields while safeguarding water quality and quantity. © 2024 Elsevier B.V.

关键词： Comprehensive spatial optimization Crop yield Haihe Basin Nitrogen losses Water security

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Land Subsidence in Xiong’an New Area,China Revealed by InSAR Observations

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Journal of Geodesy and Geoinformation Science 2021年第1期4卷 70-76页

作者： Keren DAI Peilian RAN Zhenhong LI Julian AUSTIN Jan-Peter MULLER Qiming ZENG Jingfa ZHANG Leyin HU College of Earth Sciences Chengdu University of TechnologyChengdu 610059China State Key Laboratory of Geohazard Prevention and Geoenviroment Protection Chengdu University of TechnologyChengdu 610059China College of Geological Engineering and Geomatics Chang’an UniversityXi’an 710054China Key Laboratory of Western China’s Mineral Resource and Geological Engineering Ministry of EducationXi’an 710054China School of Mathematics Statistics&PhysicsNewcastle UniversityNewcastle upon Tyne NE17RUUK Mullard Space Science Laboratory Department of Space and Climate PhysicsUniversity College LondonHolmbury St Mary RH56NTUK School of Earth and Space Sciences Peking UniversityBeijing 100871China Key Laboratory of Crustal Dynamics Institute of Crustal DynamicsChina Earthquake AdministrationBeijing 100085China Beijing Earthquake Agency Beijing 100080China

In 2017,China’s central government approved the national strategy to build Xiong’an New Area(XNA,100 km southwest to Beijing),which was announced as a"millennium strategy"and a"demo area"for a sustainable,modern,and innovative urban ***’an will draw in as much as$380 billion investment and is expected to help accelerate the development of the wider Beijing-Tianjin-Hebei(Jingjinji)*** this paper,present subsidence in the XNA area is investigated using InSAR observations for the first *** 24 SAR images acquired by European Space Agency’s Sentinel-1 satellites during the period from June 2017 to July 2018 suggest that in the north of Xiong County,the subsidence rate reaches up to 90 mm/y,which is highly correlated with the exploitation of geothermal *** the construction in the XNA area will significantly accelerate and its high-quality development,the InSAR findings could provide valuable information for future sustainable urban planning and underground infrastructure construction.

关键词： Xiong’an New Area subsidence InSAR geothermal heating Sentinel-1

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A Block Chain Dynamic key Sharing and Updating Scheme Based on the (t, n) Threshold 3rd

A Block Chain Dynamic Key Sharing and Updating Scheme Based ...

引用

3rd International Conference on Machine Learning for Cyber Security, ML4CS 2020

作者： Tang, Wei Chen, Yu-Ling Yang, Yun College of Mathematics and Statistics Guizhou University Guiyang China State Key Laboratory of Public Big Date Guizhou University Guiyang China College of Information Engineering Guizhou Radio and Television University Guiyang China Ministry of Foundation Guizhou Electronic Commerce Vocational College Guiyang China

ISBN: (纸本)9783030622220

key sharing and updating is the core problem in key management. In order to solve the centralization, security and secret share loss in the process of key management, we propose a decentralized (t, n) threshold dynamic key sharing and updating scheme in the Blockchain system, which makes full use of the advantages of Blockchain decentralization and traceability for key sharing and updating. Firstly, we generated and stored the key based on Diffie-Hellman key exchange protocol to complete the formation of the node Shared key. Secondly, a threshold scheme (t, n) of key sharing is designed based on Lagrange polynomial interpolation function, and the sub-key of each block node is stored in different places to realize key sharing of block chain. Finally, the chameleon hash function is used to update and modify the historical content for node loss in block chain sharing. The analysis shows that this scheme can realize the secure sharing and updating of the key in the Blockchain system. © 2020, Springer Nature Switzerland AG.

关键词： Hash functions

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Efficient Ring Signature Scheme Without Random Oracle from Lattices

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Chinese Journal of Electronics 2019年第2期28卷 266-272页

作者： GAO Wen HU Yupu WANG Baocang CHEN Jiangshan WANG Xin College of Electrical and Information Engineering Shaanxi University of Science and Technology State Key Laboratory of Integrated Service Networks Xidian University School of Mathematics and Statistics Minnan Normal University School of Computer Science Shaanxi Normal University

Among post-quantum alternatives, latticebased cryptography is the most promising one, due to its simple operations, reduction from aver-age-case to worstcase hardness, and supporting of rich functionalities. Ring signature enables a user to sign anonymously on behalf of an adaptively chosen group, and has multiple applications in anonymous e-voting, anonymous authentication, whistle blowing etc. However, most lattice-based ring signature schemes were constructed in the random oracle model from lattice basis delegation and they suffer large verification key sizes as a common disadvantage. This work proposes an efficient ring signature scheme from lattice basis delegation without random oracle based on the extended split-SIS problem, whose security is approximately as hard as the worst-case SIVP problem. Our scheme is proved to be anonymous and existentially unforgeable under latticebased assumptions. Finally, the verification key size is significantly reduced to a small constant, instead of increasing linearly with the number of ring members.

关键词： Lattice-based cryptography Digital signature Ring signature

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Optimal Time Delayed Control of the Combination Resonances of Viscoelastic Graphene Sheets Under Dual-Frequency Excitation

SSRN

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SSRN 2022年

作者： Liu, Chunxia Yan, Yan Wang, Wen-Quan Wang, Daohang School of Statistics and Mathematics Yunnan University of Finance and Economics Yunnan Kunming650500 China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource & Hydropower Sichuan University Chengdu610065 China Faculty of Public Security and Emergency Management Kunming University of Science and Technology Yunnan Kunming650500 China

Abstract In this study, the nonlinear combination vibration of a single-layer graphene sheet (SLGS) resting on a visco-Pasternak foundation and exposed to dual-frequency excitation was investigated. The time delayed feedback proportional-derivative (PD) controller was applied to an SLGS for the first time, and three combination resonances with two different time delays were examined. The approximate analytical solutions of nonlinear vibration equations were obtained using the multiple scales perturbation method, and their stability under the condition of combination resonance was investigated. The optimal time delay for the controller of the system was analyzed and calculated. Finally, the results of this study were compared with those of other studies. The results showed that the dual-frequency excitation intensifies the nonlinear behavior of the system such as the resonance behavior and jumping phenomenon. Further, the influence of the feedback gain coefficients and time delays on the combination resonance of the system was examined, and the results showed that the efficiency of vibration control can be improved by adjusting the feedback gain and time delay parameters. This study aims to provide theoretical guidance for the application of viscoelastic graphene sheets. © 2022, The Authors. All rights reserved.

关键词： Time delay

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