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基于时域划分的网络流量预测方法

计算机应用 2024年第S1期44卷 183-187页

作者：夏明山王丽中国科学院高能物理研究所东莞研究部北京100049 散裂中子源科学中心中子科学部广东东莞523803 中国科学院大学北京100049

网络流量的预测一般通过建立相应的分析模型分析时序序列的发展过程及趋势,缺乏对网络流量波动空间和周期特征的分析,无法对短时突变流量及短周期流量进行精准预测。为了提高网络流量的预测效果,提出一种基于时域特征分析的网络流量预... 详细信息

网络流量的预测一般通过建立相应的分析模型分析时序序列的发展过程及趋势,缺乏对网络流量波动空间和周期特征的分析,无法对短时突变流量及短周期流量进行精准预测。为了提高网络流量的预测效果,提出一种基于时域特征分析的网络流量预测方法。该方法通过分析网络流量的周期特征,建立时域划分模型,使具有相同趋势及波动空间的网络流量重组,突出短时突变流量和周期趋势特征,增强数据规律,以提高网络流量预测精度。选取反向传播(BP)神经网络、长短期记忆(LSTM)神经网络及小波神经网络(WNN)模型,采用均方误差(MSE)作为衡量标准,分别验证时域划分模式和全时域模式网络流量预测效果。结果表明,时域划分模式时BP神经网络和WNN的MSE相比全时域模式更低,其中时域划分模式BP神经网络的MSE降低为全时域模式时的1/24,说明通过分析网络流量数据建立的时域划分模型能够提高网络流量预测性能,为大规模互联网环境下的网络流量预测分析提供一种分而治之的方法。

关键词：网络流量预测特征分析流量重组时域划分神经网络

DUWe:动态未知词嵌入方法在Web异常检测中的应用

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计算机科学 2024年第S1期51卷 914-918页

作者：王丽陈刚夏明山胡皓中国科学院高能物理研究所北京100049 散裂中子源科学中心广东东莞523803 中国科学院大学北京100049

现有的基于深度学习模型的词嵌入方法用于Web异常检测时,通常将语料库中没有出现的未知词汇(Out of Vocabulary,OOV)设置为unknown,并赋予零或随机向量输入到模型中进行训练,未考虑未知词汇在Web请求语句中的上下文关系。同时,在Web系... 详细信息

现有的基于深度学习模型的词嵌入方法用于Web异常检测时,通常将语料库中没有出现的未知词汇(Out of Vocabulary,OOV)设置为unknown,并赋予零或随机向量输入到模型中进行训练,未考虑未知词汇在Web请求语句中的上下文关系。同时,在Web系统代码开发过程中,基于个人习惯并为了增加代码的可读性,程序员设计的请求路径代码往往存在一定的模式。因此,考虑到Web请求的模式和单词语义间的相关性,研究基于Word2vec的动态未知词表示方法DUWe(Dynamic Unknown Word Embedding),该方法通过分析Web请求路径中单词上下文的关系来赋予未知词向量的表示内容。在CSIC-2010和WAF Dataset数据集上的实验评估表明,增加未知词表示方法比仅用Word2vec静态特征提取方法具有更好的性能,同时在准确性、精准率、召回率和F1-Score方面均有提高,在训练时间上最大降低1.14倍。

关键词：未知词汇 Web异常检测动态词嵌入词嵌入优化深度学习

Analytical Solutions for an Isotropic Elastic Half-Plane with Complete Surface Effects Subjected to a Concentrated/Uniform Surface Load

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Acta Mechanica Solida Sinica 2024年第3期37卷 371-384页

作者： xia-Hui Pan School of Civil Engineering Henan Polytechnic UniversityJiaozuo454003China

Within the context of Gurtin-Murdoch surface elasticity theory,closed-form analytical solutions are derived for an isotropic elastic half-plane subjected to a concentrated/uniform surface *** the effects of residual surface stress and surface elasticity are *** stress function method and Fourier integral transform technique are *** solutions are provided in a compact manner that can easily reduce to special situations that take into account either one surface effect or none at *** results indicate that surface effects generally lower the stress levels and smooth the deformation profiles in the *** elasticity plays a dominant role in the in-plane elastic fields for a tangentially loaded half-plane,while the effect of residual surface stress is fundamentally crucial for the out-of-plane stress and displacement when the half-plane is normally *** the remaining situations,combined effects of surface elasticity and residual surface stress should be *** results for a concentrated surface force serve essentially as fundamental solutions of the Flamant and the half-plane Cerruti problems with surface *** solutions presented in this work may be helpful for understanding the contact behaviors between solids at the nanoscale.

关键词： Surface effects Residual surface stress Surface elasticity Half-plane Analytical solutions

Computational modelling of gas–liquid–solid multiphase free surface flow with and without evaporation

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Particuology 2024年第7期90卷 218-235页

作者： Huihuang xia Marc Kamlah Institute for Applied Materials(IAM) Karlsruhe Institute of Technology(KIT)Hermann-von Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Gas–liquid–solid multiphase systems are ubiquitous in engineering applications,*** printing,spray drying and *** a numerical framework for modelling these multiphase systems is of great *** improved,resolved computational fluid dynamics-discrete element method(CFD-DEM)framework is developed to model the multiphase free surface flow with and without *** improved capillary force model is developed to compute the capillary interactions for partially floating particles at a free *** well-known benchmark cases,namely drag coefficient calculation,the single sphere settling,and drafting-kissing-tumbling of two particles are conducted to validate the resolved CFD-DEM *** turns out that the resolved CFD-DEM model developed in this paper can accurately calculate the fluid–solid interactions and predict the trajectory of solid particles interacting with the liquid *** demonstrations,namely two particles moving along a free surface when the liquid phase evaporates,and particle transport and accumulations inside an evaporating sessile droplet show the performance of the resolved model.

关键词： Capillary force Discrete element method Liquid bridge Particle transport Resolved CFD-DEM Volume of fluid

Theoretical and experimental investigations on single-atom catalysis:Pt1/FeOx for water-gas shift reaction Shan-Fei Wang1,§,Yangyang Li2,3,§,Haiyan Wang1,Jin-xia Liang1(✉),Chun Zhu1

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Nano Research 2024年第9期17卷 8627-8637页

作者： Shan-Fei Wang Yangyang Li Haiyan Wang Jin-xia Liang Chun Zhu Botao Qiao School of Chemistry and Chemical Engineering Guizhou UniversityGuiyang 550025China CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

Oxide-supported metal single-atom catalysts(SACs)have exhibited excellent catalytic performance for water-gas shift(WGS)***,we report the single-atom catalyst Pt1/FeOx exhibits excellent medium temperature catalytic performance for WGS reactions by the density functional theory(DFT)calculations and experimental *** calculations indicate that H_(2)O molecules are easily dissociated at oxygen vacancies,and the formed*OH and*O are adsorbed on Pt1 single atoms and the adjacent O atoms,*** studying four possible reaction mechanisms,it is found that the optimal WGS reaction pathway is proceeded along the carboxyl mechanism(pathway III),in which the formation of*COOH intermediates can promote the stability of Pt1/FeOx SAC and the easier occurrence of WGS *** energy barrier of the rate-determining step during the entire reaction cycle is only 1.16 eV,showing the high activity for the medium temperature WGS reaction on Pt1/FeOx SAC,which was verified by experimental ***,the calculated turnover frequencies(TOFs)of CO_(2)and H_(2)formation on Pt1/FeOx at 610 K(337℃)can reach up to 1.14×10^(-3)s^(-1)·site^(-1)through carboxyl *** this work,we further expand the application potential of Pt1/FeOx SAC in WGS reaction.

关键词： water-gas shift(WGS)reaction single-atom catalyst(SAC) density functional theory(DFT) thermocatalysis

Regional features of pollen R-values in China

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Science China Earth Sciences 2024年第1期67卷 295-308页

作者： Jie xia Jian NI College of Life Sciences Zhejiang Normal UniversityJinhua 321004China Jinhua Mountain Observation and Research Station for Subtropical Forest Ecosystems Jinhua 321004China

Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary *** R-value,a well-established and traditional metric characterized by its simplicity and direct applicability,serves to calibrate the nonlinear disparities between surface pollen and modern *** study entails the construction of a comprehensive pollen R-value dataset for China derived from R-values published between 1987 and *** dataset,compiled after rigorous screening,calibration,and standardization processes,encompasses 898 modern pollen sampling sites and 2115 pollen R-value data entries,encapsulating 152 pollen taxa spanning 65 families and 113 *** the extracted R-values yielded the following insights:(1)A macrospatial analysis validates previously established knowledge at a site-specific ***,pollen R-value variations across China are statistically *** two-thirds of pollen taxa exhibit underrepresentation(e.g.,Taxodiaceae,Corylus,Nitraria,Tamarix,Cyperaceae,Poaceae,and Fabaceae),while the remaining one-third display overrepresentation(e.g.,Pinus,Picea,Betula,Ephedra,Chenopodiaceae,and Artemisia).The degree of underrepresentation surpasses that of overrepresentation,and the representation patterns of Castanea,Quercus,Polygonaceae,and Asteraceae are contingent upon vegetation types.(2)Pollen R-values follow distinct spatial distribution patterns within *** the woody vegetation region of eastern China,R-values progressively decline from north to south,correlating with rising temperatures and ***,in herbaceous vegetation regions of northern and western China,R-values decrease from east to west and from northeast to southwest,corresponding to increased ***,pollen R-values manifest variation contingent on pollen taxa,vegetation types,and climatic regions,even differing for the same taxa across varying

关键词： Pollen R-value Modern pollen-vegetation relationship Regional pattern Variability Paleovegetation reconstruction

“Buckets effect”in the kinetics of electrocatalytic reactions

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Journal of Energy Chemistry 2024年第2期89卷 388-396,I0010页

作者： Haowen Cui Yan-xia Chen Hefei National Laboratory for Physical Sciences at Microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic *** results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant *** consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant *** could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the *** study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.

关键词： Oxygen reduction reaction Kinetics Zero order Rectangular hyperbolic relationship pH effect

Asperuloside Promotes Apoptosis of Cervical Cancer Cells through Endoplasmic Reticulum Stress-Mitochondrial Pathway

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Chinese Journal of Integrative Medicine 2024年第1期30卷 34-41页

作者： QI Zhi-min WANG xia LIU xia ZHAO Juan Medical Examination Center Hebei Province Hospital of Chinese MedicineShijiazhuang(050011)China Department of Gynaecology and Obstetrics Hebei Province Hospital of Chinese MedicineShijiazhuang(050011)China Experimental Center for Teaching Hebei Medical UniversityShijiazhuang(050017)China

Objective: To investigate the effects of asperuloside on cervical cancer based on endoplasmic reticulum(ER) stress and mitochondrial pathway. Methods: Different doses(12.5–800 μg/mL) of asperuloside were used to treat cervical cancer cell lines Hela and CaSki to calculate the half maximal inhibitory concentration(IC_(50)) of asperuloside. The cell proliferation was analyzed by clone formation assay. Cell apoptosis, intracellular reactive oxygen species(ROS) and mitochondrial membrane potential were determined by flow cytometry. The protein expressions of cleaved-caspase-3, Bcl-2, Bax, Cyt-c, cleaved-caspase-4 and glucose-regulated protein 78(GRP78) were analyzed by Western blot. And the inhibitor of ER stress, 4-phenyl butyric acid(4-PBA) was used to treat cervical cancer cells to further verify the role of ER stress in the apoptosis of cervical cancer cells induced by asperuloside. Results: Asperuloside of 325, 650, and 1300 μg/mL significantly inhibited the proliferation and promoted apoptosis of Hela and CaSki cells(P<0.01). All doses of asperuloside significantly increased intracellular ROS levels, reduced mitochondrial membrane potential, significantly reduced Bcl-2 protein expression level, and increased Bax, Cyt-c, GRP78 and cleaved-caspase-4 expressions(P<0.01). In addition, 10 mmol/L 4-PBA treatment significantly promoted cell proliferation and reduced apoptosis(P<0.05), and 650 μg/mL asperuloside could reverse 4-PBA-induced increased cell proliferation, decreased apoptosis and cleaved-caspase-3,-4 and GRP78 protein expressions(P<0.05). Conclusion: Our study revealed the role of asperuloside in cervical cancer, suggesting that asperuloside promotes apoptosis of cervical cancer cells through ER stress-mitochondrial pathway.

关键词： asperuloside Chinese medicine cervical cancer endoplasmic reticulum stress mitochondrial damage apoptosis

A regularization algorithm of dynamic light scattering for estimating the particle size distribution of dual-substance mixture in water

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Particuology 2024年第6期89卷 246-257页

作者： Yanghong Wang Ziqiang Meng Zipei Zhang Min xia Li xia Wei Li School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China

Dynamic light scattering(DLS)is a nondestructive,well-established technique for the size characterization of proteins,nanoparticles,polymers,and colloidal ***,current DLS techniques are only applied to particle groups of single composition due to the limitation of their inversion *** this study,we propose a particle size distribution inversion algorithm based on the Tikhnonov regularization method that can be applied to the dual-substance particle *** algorithm retrieves the particle size distributions of two substances,respectively,by taking advantage of their refractive index *** simulation results reveal that the algorithm has excellent accuracy and stability when the scattering angle is 30°.Instead of the original identity matrix,the first-order difference matrix and second-order difference matrix are used as the regular matrix when utilizing the Tikhnonov algorithm,which obviously improves the anti-interference,accuracy,and stability of the ***,the inversion of particle size distribution is carried out at a 0.01%–1%noise level,which shows that the algorithm has an available antinoise ***,experimental particle size measurements for a mixture of polystyrene beads and toner particles demonstrate that the proposed algorithm is superior to the traditional Tikhnonov algorithm in applicability and accuracy.

关键词： Dynamic light scattering Dual-substance mixture Particle sized istribution Tikhnonov regularization