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Mesoscopic investigation on seismic performance of corroded reinforced concrete columns

Earthquake engineering and engineering Vibration 2022年第4期21卷 969-985页

作者： Jin Liu Li Yanxi Zhang Renbo Du Xiuli Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100024China

In addition to the normal service loadings,engineering structures may be subjected to occasional loadings such as earthquakes,which may cause severe *** the steel rebar is corroded,the damage could be more *** investigate the seismic performance of corroded RC columns,a three-dimensional mesoscale finite element model was *** this approach,concrete was considered as a three-phase composite composed of aggregate,mortar matrix and interfacial transition zone(ITZ).The nonlinear spring were used to describe the bond slip between steel and *** degradation of the material properties of the steel rebar and cover concrete as well as the bonding performance due to corrosion were taken into *** rationality of the developed numerical analysis model was verified by the good agreement between the numerical results and the available experimental *** this basis,the effect of corrosion level,axial force ratio and shear-span ratio on the seismic performance of corroded RC columns,including lateral bearing capacity,ductility,and energy consumption,were explored and *** simulation results indicate that the mesoscopic method can consider the heterogeneity of concrete,to more realistically and reasonably reflect the destruction process of structures.

关键词： reinforcement corrosion reinforced concrete column meso-scale finite element analysis seismic behavior

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Complete solutions for elastic fields induced by point load vector in functionally graded material model with transverse isotropy

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Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 411-430页

作者： Sha XIAO Zhongqi YUE Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education Beijing University of TechnologyBeijing 100124China Department of Civil Engineering The University of Hong KongHong KongChina

The paper develops and examines the complete solutions for the elastic field induced by the point load vector in a general functionally graded material(FGM)model with transverse *** FGMs are approximated with n-layered *** of the n-layered materials is homogeneous and transversely *** complete solutions of the displacement and stress fields are explicitly expressed in the forms of fifteen classical Hankel transform integrals with ten kernel *** ten kernel functions are explicitly expressed in the forms of backward transfer matrices and have clear mathematical *** singular terms of the complete solutions are analytically isolated and expressed in exact closed forms in terms of elementary harmonic *** results show that the computation of the complete solutions can be achieved with high accuracy and efficiency.

关键词： functionally graded material(FGM) transverse isotropy elasticity closedform singular solution Green's function point load vector

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PosFuzz:augmenting greybox fuzzing with effective position distribution

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Cybersecurity 2023年第4期6卷 123-143页

作者： Yanyan Zou Wei Zou JiaCheng Zhao Nanyu Zhong Yu Zhang Ji Shi Wei Huo Institute of Information Engineering Chinese Academy of SciencesBeijingChina School of Cyber Security University of Chinese Academy of SciencesBeijingChina State Key Lab of Processors Institute of Computing TechnologyChinese Academy of SciencesBeijingChina Key Laboratory of Network Assessment Technology Chinese Academy of SciencesBeijingChina Beijing Key Laboratory of Network Security and Protection Technology BeijingChina Zhongguancun Laboratory BeijingChina

Mutation-based greybox fuzzing has been one of the most prevalent techniques for security vulnerability discovery and a great deal of research work has been proposed to improve both its efficiency and ***-based greybox fuzzing generates input cases by mutating the input seed,i.e.,applying a sequence of mutation operators to randomly selected mutation positions of the ***,existing fruitful research work focuses on scheduling mutation operators,leaving the schedule of mutation positions as an overlooked aspect of fuzzing *** paper proposes a novel greybox fuzzing method,PosFuzz,that statistically schedules mutation positions based on their historical *** makes use of a concept of effective position distribution to represent the semantics of the input and to guide the *** first utilizes Good-Turing frequency estimation to calculate an effective position distribution for each mutation *** then leverages two sampling methods in different mutating stages to select the positions from the *** have implemented PosFuzz on top of AFL,AFLFast and MOPT,called Pos-AFL,-AFLFast and-MOPT respectively,and evaluated them on the UNIFUZZ benchmark(20 widely used open source programs)and LAVA-M *** result shows that,under the same testing time budget,the Pos-AFL,-AFLFast and-MOPT outperform their counterparts in code coverage and vulnerability discovery *** with AFL,AFLFast,and MOPT,PosFuzz gets 21%more edge coverage and finds 133%more paths on *** also triggers 275%more unique bugs on average.

关键词： Greybox fuzzing Mutation position Mutation operator Code coverage Vulnerability discovery

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Imbalanced rock burst assessment using variational autoencoder-enhanced gradient boosting algorithms and explainability

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Underground Space 2024年第4期17卷 226-245页

作者： Shan Lin Zenglong Liang Miao Dong Hongwei Guo Hong Zheng Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China Department of Civil and Environmental Engineering The Hong Kong Polytechnic University(PolyU)Hung HomKowloon 999077Hong KongChina

We conducted a study to evaluate the potential and robustness of gradient boosting algorithms in rock burst assessment,established a variational autoencoder(VAE)to address the imbalance rock burst dataset,and proposed a multilevel explainable artificial intelligence(XAI)tailored for tree-based ensemble *** collected 537 data from real-world rock burst records and selected four critical features contributing to rock burst ***,we employed data visualization to gain insight into the data’s structure and performed correlation analysis to explore the data distribution and feature ***,we set up a VAE model to generate samples for the minority class due to the imbalanced class *** conjunction with the VAE,we compared and evaluated six state-of-theart ensemble models,including gradient boosting algorithms and the classical logistic regression model,for rock burst *** results indicated that gradient boosting algorithms outperformed the classical single models,and the VAE-classifier outperformed the original classifier,with the VAE-NGBoost model yielding the most favorable *** to other resampling methods combined with NGBoost for imbalanced datasets,such as synthetic minority oversampling technique(SMOTE),SMOTE-edited nearest neighbours(SMOTE-ENN),and SMOTE-tomek links(SMOTE-Tomek),the VAE-NGBoost model yielded the best ***,we developed a multilevel XAI model using feature sensitivity analysis,Tree Shapley Additive exPlanations(Tree SHAP),and Anchor to provide an in-depth exploration of the decision-making mechanics of VAE-NGBoost,further enhancing the accountability of treebased ensemble models in predicting rock burst occurrences.

关键词： Gradient boosting VAE Ensemble learning Explainable artificial intelligence(XAI) Rock burst

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A Novel S-Box GenerationMethodology Based on the Optimized GANModel

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Computers, Materials & Continua 2023年第8期76卷 1911-1927页

作者： Runlian Zhang Rui Shu Yongzhuang Wei Hailong Zhang Xiaonian Wu Guangxi Key Laboratory of Cryptography and Information Security Guilin University of Electronic TechnologyGuilin541004China State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of SciencesBeijing100085China

S-boxes can be the core component of block ciphers,and how to efficiently generate S-boxes with strong cryptographic properties appears to be an important task in the design of block *** this work,an optimized model based on the generative adversarial network(GAN)is proposed to generate 8-bit *** central idea of this optimized model is to use loss function constraints for *** specially,the Advanced Encryption Standard(AES)S-box is used to construct the sample dataset via the affine equivalence ***,three models are respectively built and cross-trained to generate 8-bit S-boxes based on three extended frameworks of GAN,i.e.,Deep Convolution Generative Adversarial Networks(DCGAN),Wasserstein Generative Adversarial Networks(WGAN),and WassersteinGenerativeAdversarial NetworkwithGradient Penalty(WGANGP).Besides,an optimized model based onWGAN-GP referred to asWGPIM is also proposed,which adds the loss function constraints to the generator network of the WGAN-GP model,including bijection loss,differential uniformity loss,and nonlinearity *** this case,8-bit S-boxes can be generated with *** results illustrate that the WGP-IM model can generate S-boxes with excellent cryptographic *** particular,the optimal differential uniformity of the generated S-boxes can be reduced to 8,and the nonlinearity can be up to *** with previous S-box generation methods,this new method is simpler and it can generate S-boxes with excellent cryptographic properties.

关键词： S-box generative adversarial network loss function affine equivalence

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Towards optimized tensor code generation for deep learning on sunway many-core processor

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Frontiers of Computer Science 2024年第2期18卷 1-15页

作者： Mingzhen LI Changxi LIU Jianjin LIAO Xuegui ZHENG Hailong YANG Rujun SUN Jun XU Lin GAN Guangwen YANG Zhongzhi LUAN Depei QIAN State Key Laboratory of Software Development Environment Beijing 100191China School of Computer Science and Engineering Beihang UniversityBeijing 100191China National University of Singapore Singapore 119077Singapore State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi 214000China Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing 100854China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China

The flourish of deep learning frameworks and hardware platforms has been demanding an efficient compiler that can shield the diversity in both software and hardware in order to provide application *** the existing deep learning compilers,TVM is well known for its efficiency in code generation and optimization across diverse hardware *** the meanwhile,the Sunway many-core processor renders itself as a competitive candidate for its attractive computational power in both scientific computing and deep learning *** paper combines the trends in these two ***,we propose swTVM that extends the original TVM to support ahead-of-time compilation for architecture requiring cross-compilation such as *** addition,we leverage the architecture features during the compilation such as core group for massive parallelism,DMA for high bandwidth memory transfer and local device memory for data locality,in order to generate efficient codes for deep learning workloads on *** experiment results show that the codes generated by swTVM achieve 1.79x improvement of inference latency on average compared to the state-of-the-art deep learning framework on Sunway,across eight representative *** work is the first attempt from the compiler perspective to bridge the gap of deep learning and Sunway processor particularly with productivity and efficiency in *** believe this work will encourage more people to embrace the power of deep learning and Sunwaymany-coreprocessor.

关键词： sunway processor deep learning compiler code generation performance optimization

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Predict the evolution of mechanical property of Al-Li alloys in a marine environment

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Defence technology（防务技术） 2024年第1期31卷 557-566页

作者： Wei Li Lin Xiang Guang Wu Hongli Si Jinyan Chen Yiming Jin Yan Su Jianquan Tao Chunyang Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100036China Chongqing Innovation Center Beijing Institute of TechnologyChongqing400044China First Research Institute of the Ministry of Public Security for PR China Beijing100036China Southwest Technology and Engineering Research Institute Chongqing400039China

The ocean is one of the essential fields of national defense in the future,and more and more attention is paid to the lightweight research of Marine equipment and *** study it is to develop a Machine learning(ML)-based prediction method to study the evolution of the mechanical properties of Al-Li alloys in the marine *** obtained the mechanical properties of Al-Li alloy samples under uniaxial tensile deformation at different exposure times through Marine exposure *** obtained the strain evolution by digital image correlation(DIC).The strain field images are voxelized using 2D-Convolutional Neural Networks(CNN)autoencoders as input data for Long Short-Term Memory(LSTM)neural ***,the output data of LSTM neural networks combined with corrosion features were input into the Back Propagation(BP)neural network to predict the mechanical properties of Al-Li *** main conclusions are as follows:*** variation law of mechanical properties of2297-T8 in the Marine atmosphere is *** the increase in outdoor exposure test time,the tensile elastic model of 2297-T8 changes slowly,within 10%,and the tensile yield stress changes significantly,with a maximum attenuation of 23.6%.*** prediction model can predict the strain evolution and mechanical response simultaneously with an error of less than 5%.*** study shows that a CNN/LSTM system based on machine learning can be built to capture the corrosion characteristics of Marine exposure *** results show that the relationship between corrosion characteristics and mechanical response can be predicted without considering the microstructure evolution of metal materials.

关键词： Marine environment Al-Li alloy Machine learning Corrosion

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Deformation characteristics and instability mechanism of transportation hub under downward traversal conditions of the double-track super-large diameter shield tunnel

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Geohazard Mechanics 2024年第2期2卷 131-142页

作者： Xiangzhi Gao Aijun Yao The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing100124PR China

To investigate the deformation characteristics and instability mechanism of the transportation hub underdownward traversal conditions of the double-track super-large diameter shield tunnel, take the example of beijingEast Sixth Ring Road into the ground reconstruction project. Using the field experimental monitoring method andnumerical simulation method, after verifying the accuracy of the model, this manuscript begins to unfold theanalysis. The results show that, without any deformation prevention and control measures, The basement raft ofthe underground structure of the transportation hub will produce a deformation difference of 18 mm, and thetensile stress is more than 1.43 MPa, the inhomogeneous deformation and structural cracking will lead tostructural instability and groundwater surges, which seriously affects the safe operation of the transportation hubstation. When control measures are taken, the deformation and stress of the base raft slab of the undergroundstructure of the transportation hub are within the prescribed limits, which can ensure the safe operation of thestation. The displacement of the base slab of the underground structure in the horizontal direction of the crosssection is all pointing to the east, and the overall trend is to shift from the first tunnel to the backward tunnel. Thehorizontal displacement of the base slab in the direction of the tunnel axis all points to the beginning of thecrossing, and the displacement of the slab in the vertical direction is distributed as "rising in the middle andsinking in the surroundings". For a two-lane super-large diameter shield tunnel penetrating an undergroundstructure, there are two mechanical effects: unloading rebound and perimeter rock pressure. The above deformation characteristics are the superposition effect produced by the two, and this fine assessment of the deformation of the raft foundation provides a scientific basis for formulating the deformation control countermeasuresof the crossing

关键词： Super-large diameter shield Transportation hub Deformation characteristics Mechanical mechanism Downward traverse

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Time-domain dynamic constitutive model suitable for mucky soil site seismic response

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Earthquake engineering and engineering Vibration 2024年第1期23卷 1-13页

作者： Dong Qing Chen Su Jin Liguo Zhou Zhenghua Li Xiaojun Architectural Engineering Institute Huaiyin Institute of TechnologyHuai’an 223600China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100020China Institute of Geophysics China Earthquake AdministrationBeijing 100089China College of Transportation Science and Engineering Nanjing Tech UniversityNanjing 211816China

Soil nonlinear behavior displays noticeable effects on the site seismic *** study proposes a new functional expression of the skeleton curve to replace the hyperbolic skeleton *** integrating shear modulus and combining the dynamic skeleton curve and the damping degradation coefficient,the constitutive equation of the logarithmic dynamic skeleton can be obtained,which considers the damping effect in a soil dynamics *** on the finite difference method and the multi-transmitting boundary condition,a 1D site seismic response analysis program called Soilresp1D has been developed herein and used to analyze the time-domain seismic response in three types of *** the same time,this study also provides numerical simulation results based on the hyperbolic constitutive model and the equivalent linear *** results verify the rationality of the new soil dynamic constitutive *** can analyze the mucky soil site nonlinear seismic response,reflecting the deformation characteristics and damping effect of the silty *** hysteresis loop area is more extensive,and the residual strain is evident.

关键词： seismic response time-domain dynamic constitutive model logarithmic dynamic skeleton dampening effect mucky soil

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Minimizing the cost of periodically replicated systems via model and quantitative analysis

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Frontiers of Computer Science 2024年第5期18卷 11-24页

作者： Chenhao ZHANG Liang WANG Limin XIAO Shixuan JIANG Meng HAN Jinquan WANG Bing WEI Guangjun QIN State Key Laboratory of Software Development Environment Beihang UniversityBeijing 100191China School of Computer Science and Engineering Beihang UniversityBeijing 100191China School of Cyberspace Security Hainan UniversityHaikou 570228China Smart City College Beijing Union UniversityBeijing 100101China

Geographically replicating objects across multiple data centers improves the performance and reliability of cloud storage *** consistent replicas comes with high synchronization costs,as it faces more expensive WAN transport prices and increased *** replication is the widely used technique to reduce the synchronization *** replication strategies in existing cloud storage systems are too static to handle traffic changes,which indicates that they are inflexible in the face of unforeseen loads,resulting in additional synchronization *** propose quantitative analysis models to quantify consistency and synchronization cost for periodically replicated systems,and derive the optimal synchronization period to achieve the best tradeoff between consistency and synchronization *** on this,we propose a dynamic periodic synchronization method,Sync-Opt,which allows systems to set the optimal synchronization period according to the variable load in clouds to minimize the synchronization *** results demonstrate the effectiveness of our *** with the policies widely used in modern cloud storage systems,the Sync-Opt strategy significantly reduces the synchronization cost.

关键词： periodic replication consistency maintenance synchronization cost synchronization strategy

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