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Development of a convolutional neural network based geomechanical upscaling technique for heterogeneous geological reservoir

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2111-2125页

作者： Zhiwei Ma Xiaoyan ou Bo Zhang Earth and Environmental Sciences Division Los Alamos National LaboratoryLos AlamosUSA Civil and Environmental Engineering University of AlbertaEdmontonCanada

Geomechanical assessment using coupled reservoir-geomechanical simulation is becoming increasingly important for analyzing the potential geomechanical risks in subsurface geological ***,a robust and efficient geomechanical upscaling technique for heterogeneous geological reservoirs is lacking to advance the applications of three-dimensional(3D)reservoir-scale geomechanical simulation considering detailed geological ***,we develop convolutional neural network(CNN)proxies that reproduce the anisotropic nonlinear geomechanical response caused by lithological heterogeneity,and compute upscaled geomechanical properties from CNN *** CNN proxies are trained using a large dataset of randomly generated spatially correlated sand-shale realizations as inputs and simulation results of their macroscopic geomechanical response as *** trained CNN models can provide the upscaled shear strength(R^(2)>0.949),stress-strain behavior(R^(2)>0.925),and volumetric strain changes(R^(2)>0.958)that highly agree with the numerical simulation results while saving over two orders of magnitude of computational *** is a major advantage in computing the upscaled geomechanical properties directly from geological realizations without the need to perform local numerical simulations to obtain the geomechanical *** proposed CNN proxybased upscaling technique has the ability to(1)bridge the gap between the fine-scale geocellular models considering geological uncertainties and computationally efficient geomechanical models used to assess the geomechanical risks of large-scale subsurface development,and(2)improve the efficiency of numerical upscaling techniques that rely on local numerical simulations,leading to significantly increased computational time for uncertainty quantification using numerous geological realizations.

关键词： Upscaling Lithological heterogeneity Convolutional neural network(CNN) Anisotropic shear strength Nonlinear stressestrain behavior

Pixel-level crack segmentation of tunnel lining segments based on an encoder–decoder network

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Frontiers of Structural and Civil Engineering 2024年第5期18卷 681-698页

作者： Shaokang Hou Zhigang ou Yuequn HUANG Yaoru LIU State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China China Renewable Energy Engineering Institute Beijing 100120China State Key Laboratory of Stimulation and Regulation of Water Cycles in River Basins China Institute of Water Resources and Hydropower ResearchBeijing 100038China Hunan Provincial Water Resources Development&Investment Co. Ltd.Changsha 410007China

Regular detection and repair for lining cracks are necessary to guarantee the safety and stability of *** development of computer vision has greatly promoted structural health *** study proposes a novel encoder–decoder structure,CrackRecNet,for semantic segmentation of lining segment cracks by integrating improved VGG-19 into the U-Net *** image acquisition equipment is designed based on a camera,3-dimensional printing(3DP)bracket and two laser rangefinders.A tunnel concrete structure crack(TCSC)image data set,containing images collected from a double-shield tunnel boring machines(TBM)tunnel in China,was *** data preprocessing operations,such as brightness adjustment,pixel resolution adjustment,flipping,splitting and annotation,2880 image samples with pixel resolution of 448×448 were *** model was implemented by Pytorch in PyCharm processed with 4 NVIDIA TITAN V *** the experiments,the proposed CrackRecNet showed better prediction performance than U-Net,TernausNet,and *** paper also discusses GPU parallel acceleration effect and the crack maximum width quantification.

关键词： tunnel lining segment crack detection semantic segmentation convolutional neural network encoder-decoder structure

Asymmetric time-varying integral barrier Lyapunov function based adaptive optimal control for nonlinear systems with dynamic state constraints

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Frontiers of Information Technology & Electronic Engineering 2024年第6期25卷 887-902页

作者： Yan WEI Mingshuang HAO Xinyi YU Linlin ou College of Information Engineering Zhejiang University of TechnologyHangzhou 310023China

This paper investigates the issue of adaptive optimal tracking control for nonlinear systems with dynamic state *** asymmetric time-varying integral barrier Lyapunov function(ATIBLF)based integral reinforcement learning(IRL)control algorithm with an actor–critic structure is first *** ATIBLF items are appropriately arranged in every step of the optimized backstepping control design to ensure that the dynamic full-state constraints are never ***,optimal virtual/actual control in every backstepping subsystem is decomposed with ATIBLF items and also with an adaptive optimized ***,neural networks are used to approximate the gradient value *** to the Lyapunov stability theorem,the boundedness of all signals of the closed-loop system is proved,and the proposed control scheme ensures that the system states are within predefined compact ***,the effectiveness of the proposed control approach is validated by simulations.

关键词： State constraints Asymmetric time-varying integral barrier Lyapunov function(ATIBLF) Adaptive optimal control Nonlinear systems

Entangled photons enabled ultrafast stimulated Raman spectroscopy for molecular dynamics

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Light(Science & Applications) 2024年第8期13卷 1615-1622页

作者： Jiahao Joel Fan Zhe-Yu ou Zhedong Zhang Department of Physics City University of Hong KongKowloonHong Kong SARChina City University of Hong Kong Shenzhen Research InstituteShenzhenGuangdongChina

Quantum entanglement has emerged as a great resource for studying the interactions between molecules and *** propose a new scheme of stimulated Raman scattering with entangled photons.A quantum ultrafast Raman spectroscopy is developed for condensed-phase molecules,to monitor the exciton populations and *** results are obtained,showing an entanglement-enabled time-frequency scale not attainable by classical *** Raman signal presents an unprecedented selectivity of molecular correlation functions,as a result of the Hong-ou-Mandel *** work suggests a new paradigm of using an unconventional interferometer as part of spectroscopy,with the potential to unveil advanced information about complex materials.

关键词： materials. spectroscopy selectivity

Amorphous Sb/C composite with isotropic expansion property as an ultra-stable and high-rate anode for lithium-ion batteries

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Rare Metals 2024年第5期43卷 2039-2052页

作者： Ze-Zhou Yang Cheng-yi Zhang Yu-Qing ou Zhi-Kang Su Yan Zhao Heng-Jiang Cong Xin-Ping Ai Jiang-Feng Qian Hubei Key Laboratory of Electrochemical Power Sources College of Chemistry and Molecular SciencesWuhan UniversityWuhan430072China Institute of Technological Sciences Wuhan UniversityWuhan 430072China

Antimony(Sb)is an intriguing anode material for Li-ion batteries(LIBs)owing to its high theoretical capacity of 660 m Ah·g^(-1)and appropriate working potential of~0.8 V(***^(+)/Li).However,just like all alloying materials,the Sb anode suffers from huge volume expansion(230%)during repeated insertion/extraction of Li+ions,resulting in structural deterioration and rapid capacity *** this work,a novel amorphous Sb/C composite with atomically dispersed Sb particles in carbon matrix is prepared via a straightforward high-energy ball milling *** intimate intermixing of amorphous Sb with C provides homogeneous element distribution and isotropic volume expansion during cycling,resulting in persistent structural ***,the disordered structure of amorphous material shortens the diffusion distance of lithium ions/electrons,promoting fast reaction kinetics and rate *** from the aforementioned effects,the amorphous Sb/C exhibits a high reversible capacity of537.4 m Ah·g^(-1)at 0.1 A·g^(-1)and retains 201.0 m Ah·g^(-1)at an ultrahigh current rate of 10.0 A·g^(-1).Even after 1500deep cycles at 2.0 A·g^(-1),the amorphous Sb/C electrode still maintains 86.3%of its initial capacity,which outperforms all existing Sb-based anodes reported so *** analysis further reveals a greatly reduced volume variation of merely 34.6%for the amorphous Sb/C electrode,much lower than that of 223.1%for crystalline Sb *** study presents a new approach to stabilizing Sb-based alloy anodes and contributes to the construction of high-performance amorphous anode materials for LIBs,enabling advanced energy storage.

关键词： Amorphous Sb/C anode Homogeneous element distribution Isotropic volume expansion Ultra-long cycle stability High-rate capability Lithium-ion battery

Performance Prediction Based Workload Scheduling in Co-Located Cluster

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2043-2067页

作者： Dongyang ou Yongjian Ren Congfeng Jiang School of Computer Science and Technology Hangzhou Dianzi UniversityHangzhou310018China

Cloud service providers generally co-locate online services and batch jobs onto the same computer cluster,where the resources can be pooled in order to maximize data center resource *** to resource competition between batch jobs and online services,co-location frequently impairs the performance of online *** study presents a quality of service(QoS)prediction-based schedulingmodel(QPSM)for *** performance prediction of QPSM consists of two parts:the prediction of an online service’s QoS anomaly based on XGBoost and the prediction of the completion time of an offline batch job based on ***-line service QoS anomaly prediction is used to evaluate the influence of batch jobmix on on-line service performance,and batch job completion time prediction is utilized to reduce the total waiting time of batch *** the same number of batch jobs are scheduled in experiments using typical test sets such as CloudSuite,the scheduling time required by QPSM is reduced by about 6 h on average compared with the first-come,first-served strategy and by about 11 h compared with the random scheduling *** with the non-co-located situation,QPSM can improve CPU resource utilization by 12.15% and memory resource utilization by 5.7% on *** show that the QPSM scheduling strategy proposed in this study can effectively guarantee the quality of online services and further improve cluster resource utilization.

关键词： Co-located cluster workload scheduling online service batch jobs data center

Side-Channel Leakage Analysis of Inner Product Masking

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Computers, Materials & Continua 2024年第4期79卷 1245-1262页

作者： Yuyuan Li Lang Li Yu ou College of Computer Science and Technology Hengyang Normal UniversityHengyang421002China Hunan Provincial Key Laboratory of Intelligent Information Processing and Application Hengyang Normal UniversityHengyang421002China

The Inner Product Masking(IPM)scheme has been shown to provide higher theoretical security guarantees than the BooleanMasking(BM).This scheme aims to increase the algebraic complexity of the coding to achieve a higher level of *** previous work unfolds when certain(adversarial and implementation)conditions are met,and we seek to complement these investigations by understanding what happens when these conditions deviate from their expected *** this paper,we investigate the security characteristics of IPM under different *** adversarial condition,the security properties of first-order IPMs obtained through parametric characterization are preserved in the face of univariate and bivariate *** implementation condition,we construct two new polynomial leakage functions to observe the nonlinear leakage of the IPM and connect the security order amplification to the nonlinear *** observe that the security of IPMis affected by the degree and the linear component in the leakage *** addition,the comparison experiments from the coefficients,signal-to-noise ratio(SNR)and the public parameter show that the security properties of the IPM are highly implementation-dependent.

关键词： Side-channel analysis inner product masking mutual information nonlinear leakage

Effects of surface chlorine atoms on charge distribution and reaction barriers for photocatalytic CO_(2)reduction

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Nano Materials Science 2024年第2期6卷 235-243页

作者： Wendong Zhang Wenjun Ma Yuerui Ma Peng Chen Qingqing Ye yi Wang Zhongwei Jiang yingqing ou Fan Dong Chongqing Key Laboratory of Green Synthesis and Application&Chongqing Key Laboratory of Inorganic Functional Materials College of ChemistryChongqing Normal UniversityChongqing401331China Suzhou Industrial Technology Research Institute of Zhejiang University Jiangsu215000China Department of Chemistry Faculty of ScienceNational University of SingaporeSingapore117543Singapore Yangtze Delta Region Institute(Huzhou)&Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaHuzhou313001China

Photocatalytic CO_(2)reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming ***,the conversion efficiency and product selectivity are still low due to the sluggish dynamics of transfer processes involved in proton-assisted multi-electron *** the formation energy barriers of intermediate products is an effective method to enhance the selectivity and productivity of final *** this study,we aim to regulate the surface electronic structure of Bi_(2)WO_(6)by doping surface chlorine atoms to achieve effective photocatalytic CO_(2)*** Cl atoms can enhance the absorption ability of light,affect its energy band structure and promote charge *** with DFT calculations,it is revealed that surface Cl atoms can not only change the surface charge distribution which affects the competitive adsorption of H_(2)O and CO_(2),but also lower the formation energy barrier of intermediate products to generate more intermediate*COOH,thus facilitating CO ***,this study demonstrates a promising surface halogenation strategy to enhance the photocatalytic CO_(2)reduction activity of a layered structure Bi-based catalyst.

关键词： Surface chlorine atoms Charge distribution Reaction barriers Photocatalytic CO_(2)reduction Bi_(2)WO_(6)

Crowdsourcing RTK:a new GNSS positioning framework for building spatial high-resolution atmospheric maps based on massive vehicle GNSS data

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Satellite Navigation 2024年第1期5卷 91-108页

作者： Hongjin Xu Xingyu Chen Jikun ou Yunbin Yuan State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and Technology(APM)Chinese Academy of Sciences(CAS)Wuhan430071China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina

High-quality spatial atmospheric delay correction information is essential for achieving fast integer ambiguity resolution(AR)in precise ***,traditional real-time precise positioning frameworks(i.e.,NRTK and PPP-RTK)depend on spatial low-resolution atmospheric delay correction through the expensive and sparsely distributed CORS *** results in limited public *** the mass production of autonomous driving vehicles,more cost-effective and widespread data sources can be explored to create spatial high-resolution atmospheric *** this study,we propose a new GNSS positioning framework that relies on dual base stations,massive vehicle GNSS data,and crowdsourced atmospheric delay correction maps(CAM).The map is easily produced and updated by vehicles equipped with GNSS receivers in a crowd-sourced ***,the map consists of between-station single-differenced ionospheric and tropospheric *** introduce the whole framework of CAM initialization for individual vehicles,on-cloud CAM maintenance,and CAM-augmented user-end *** map data are collected and preprocessed in ***,the crowdsourced data are uploaded to a cloud *** massive data from multiple vehicles are merged in the cloud to update the CAM in ***,the CAM will augment the user positioning *** framework forms a beneficial cycle where the CAM’s spatial resolution and the user positioning performance mutually improve each *** validate the performance of the proposed framework in real-world experiments and the applied potency at different spatial *** highlight that this framework is a reliable and practical positioning solution that meets the requirements of ubiquitous high-precision positioning.

关键词： New GNSS positioning framework Spatial high-resolution atmospheric delay correction Crowdsourced atmospheric delay correction maps Crowdsourced ionosphere Crowdsourced troposphere Ubiquitous