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Trends in Event Understanding and Caption Generation/Reconstruction in Dense Video:A Review
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作者 Ekanayake Mudiyanselage Chulabhaya Lankanatha Ekanayake Abubakar Sulaiman Gezawa Yunqi Lei 《Computers, Materials & Continua》 SCIE EI 2024年第3期2941-2965,共25页
Video description generates natural language sentences that describe the subject,verb,and objects of the targeted Video.The video description has been used to help visually impaired people to understand the content.It... Video description generates natural language sentences that describe the subject,verb,and objects of the targeted Video.The video description has been used to help visually impaired people to understand the content.It is also playing an essential role in devolving human-robot interaction.The dense video description is more difficult when compared with simple Video captioning because of the object’s interactions and event overlapping.Deep learning is changing the shape of computer vision(CV)technologies and natural language processing(NLP).There are hundreds of deep learning models,datasets,and evaluations that can improve the gaps in current research.This article filled this gap by evaluating some state-of-the-art approaches,especially focusing on deep learning and machine learning for video caption in a dense environment.In this article,some classic techniques concerning the existing machine learning were reviewed.And provides deep learning models,a detail of benchmark datasets with their respective domains.This paper reviews various evaluation metrics,including Bilingual EvaluationUnderstudy(BLEU),Metric for Evaluation of Translation with Explicit Ordering(METEOR),WordMover’s Distance(WMD),and Recall-Oriented Understudy for Gisting Evaluation(ROUGE)with their pros and cons.Finally,this article listed some future directions and proposed work for context enhancement using key scene extraction with object detection in a particular frame.Especially,how to improve the context of video description by analyzing key frames detection through morphological image analysis.Additionally,the paper discusses a novel approach involving sentence reconstruction and context improvement through key frame object detection,which incorporates the fusion of large languagemodels for refining results.The ultimate results arise fromenhancing the generated text of the proposedmodel by improving the predicted text and isolating objects using various keyframes.These keyframes identify dense events occurring in the video sequence. 展开更多
关键词 Video description video to text video caption sentence reconstruction
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Synergistic Swarm Optimization Algorithm
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作者 Sharaf Alzoubi Laith Abualigah +3 位作者 Mohamed Sharaf Mohammad Sh.Daoud Nima Khodadadi Heming Jia 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第6期2557-2604,共48页
This research paper presents a novel optimization method called the Synergistic Swarm Optimization Algorithm(SSOA).The SSOA combines the principles of swarmintelligence and synergistic cooperation to search for optima... This research paper presents a novel optimization method called the Synergistic Swarm Optimization Algorithm(SSOA).The SSOA combines the principles of swarmintelligence and synergistic cooperation to search for optimal solutions efficiently.A synergistic cooperation mechanism is employed,where particles exchange information and learn from each other to improve their search behaviors.This cooperation enhances the exploitation of promising regions in the search space while maintaining exploration capabilities.Furthermore,adaptive mechanisms,such as dynamic parameter adjustment and diversification strategies,are incorporated to balance exploration and exploitation.By leveraging the collaborative nature of swarm intelligence and integrating synergistic cooperation,the SSOAmethod aims to achieve superior convergence speed and solution quality performance compared to other optimization algorithms.The effectiveness of the proposed SSOA is investigated in solving the 23 benchmark functions and various engineering design problems.The experimental results highlight the effectiveness and potential of the SSOA method in addressing challenging optimization problems,making it a promising tool for a wide range of applications in engineering and beyond.Matlab codes of SSOA are available at:https://www.mathworks.com/matlabcentral/fileexchange/153466-synergistic-swarm-optimization-algorithm. 展开更多
关键词 Synergistic swarm optimization algorithm optimization algorithm METAHEURISTIC engineering problems benchmark functions
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Allocation patterns of nonstructural carbohydrates in response to CO_(2)elevation and nitrogen deposition in Cunninghamia lanceolata saplings 被引量:2
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作者 Wenhui Zheng Renshan Li +7 位作者 Qingpeng Yang Weidong Zhang Ke Huang Xin Guan Longchi Chen Xin Yu Qingkui Wang Silong Wang 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第1期87-98,共12页
Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function... Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function and whole-plant level C cycling.CO_(2)elevation and nitrogen(N)deposition,which are two major environmental issues worldwide,aff ect plant photosynthetic C assimilation and C release in forest ecosystems.However,information regarding the eff ect of CO_(2)elevation and N deposition on NSC storage in diff erent organs remains limited,especially regarding the trade-off between growth and NSC reserves.Therefore,here we analyzed the variations in the NSC storage in diff erent organs of Chinese fi r(Cunninghamia lanceolata)under CO_(2)elevation and N addition and found that NSC concentrations and contents in all organs of Chinese fi r saplings increased remarkably under CO_(2)elevation.However,N addition induced diff erential accumulation of NSC among various organs.Specifi cally,N addition decreased the NSC concentrations of needles,branches,stems,and fi ne roots,but increased the NSC contents of branches and coarse roots.The increase in the NSC contents of roots was more pronounced than that in the NSC content of aboveground organs under CO_(2)elevation.The role of N addition in the increase in the structural biomass of aboveground organs was greater than that in the increase in the structural biomass of roots.This result indicated that a diff erent tradeoff between growth and NSC storage occurred to alleviate resource limitations under CO_(2)elevation and N addition and highlights the importance of separating biomass into structural biomass and NSC reserves when investigating the eff ects of environmental change on biomass allocation. 展开更多
关键词 Biomass partition CO_(2)elevation N deposition Nonstructural carbohydrates Structural biomass
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Sensor Network Structure Recognition Based on P-law
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作者 Chuiju You Guanjun Lin +3 位作者 Jinming Qiu Ning Cao Yundong Sun Russell Higgs 《Computer Systems Science & Engineering》 SCIE EI 2023年第8期1277-1292,共16页
A sensor graph network is a sensor network model organized according to graph network structure.Structural unit and signal propagation of core nodes are the basic characteristics of sensor graph networks.In sensor net... A sensor graph network is a sensor network model organized according to graph network structure.Structural unit and signal propagation of core nodes are the basic characteristics of sensor graph networks.In sensor networks,network structure recognition is the basis for accurate identification and effective prediction and control of node states.Aiming at the problems of difficult global structure identification and poor interpretability in complex sensor graph networks,based on the characteristics of sensor networks,a method is proposed to firstly unitize the graph network structure and then expand the unit based on the signal transmission path of the core node.This method which builds on unit patulousness and core node signal propagation(called p-law)can rapidly and effectively achieve the global structure identification of a sensor graph network.Different from the traditional graph network structure recognition algorithms such as modularity maximization and spectral clustering,the proposed method reveals the natural evolution process and law of graph network subgroup generation.Experimental results confirm the effectiveness,accuracy and rationality of the proposed method and suggest that our method can be a new approach for graph network global structure recognition. 展开更多
关键词 Sensor network graph network P-law unit subgroup structure recognition
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Propagation of Airy beams from right-handed material to left-handed material 被引量:6
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作者 林惠川 蒲继雄 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期221-226,共6页
Based on the ABCD matrix formalism,the propagation property of an Airy beam from right-handed material(RHM) to left-handed material(LHM) is investigated.The result shows that when the Airy beam propagates in the L... Based on the ABCD matrix formalism,the propagation property of an Airy beam from right-handed material(RHM) to left-handed material(LHM) is investigated.The result shows that when the Airy beam propagates in the LHM,the intensity self-bending due to its propagation in the RHM can be compensated.In particular,if the propagation distance in the RHM is equal to that in the LHM and the refractive index of the LHM is n L =-1,the transverse intensity distribution of the Airy beam can return to its original state. 展开更多
关键词 left-handed material right-handed material Airy beams self-bending
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Focusing of Partially Coherent Vortex Beams by an Aperture Lens 被引量:6
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作者 饶连周 蒲继雄 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第5期1252-1255,共4页
The focusing properties of partially coherent vortex wave fields are studied. Expressions are derived for the intensity distribution and the degree of coherence near the geometrical focus. It is found that the size of... The focusing properties of partially coherent vortex wave fields are studied. Expressions are derived for the intensity distribution and the degree of coherence near the geometrical focus. It is found that the size of coherence vortex dark core in the focal region depends on the topological charges and normalized coherence lengths. It is found that the desired vortex dark core near the geometrical focus can be generated by choosing appropriate values of parameters. The degree of coherence possesses a pair of phase singularities regions in the geometrical focus neighbourhood. 展开更多
关键词 ORBITAL ANGULAR-MOMENTUM HOLLOW GAUSSIAN BEAMS PHASE SINGULARITIES OPTICALVORTICES
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Design, Optimization and Control of Extractive Distillation for Separation of Ethyl Acetate-Ethanol-Water Mixture Using Ionic Liquids 被引量:5
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作者 Ma Shoutao Shang Xianyong +3 位作者 Li Lumin Xue Changyong Li Jie Sun Lanyi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2019年第1期123-132,共10页
In this work, the process simulation of pressure-swing distillation(PSD) and extractive distillation(ED) using ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([bmim][OAc]) as the entrainer for separation of ethyl... In this work, the process simulation of pressure-swing distillation(PSD) and extractive distillation(ED) using ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([bmim][OAc]) as the entrainer for separation of ethyl acetateethanol-water mixture is performed. The design parameters of the two distillation processes are optimized with the minimum total annual cost(TAC) serving as the objective function. The results show that the TAC saving of ED process is 35.27% in comparison with that of PSD process in the case of achieving the same purity and yield of ethyl acetate.In addition, the dynamic controllability of ED process is further studied. The traditional two-point temperature control structure is proposed for the ED process, and it works pretty well while taking into account the disturbances in both feed rate and feed composition. 展开更多
关键词 IONIC liquids extractive DISTILLATION simulation process control
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Formation of Small Bottle Light Beams 被引量:4
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作者 饶连周 蒲继雄 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第12期3412-3415,共4页
A method for obtaining small bottle light beams, e.g. 0.92λ×0.4λ, in a high numerical-aperture lens system is proposed and numerically demonstrated. This can be achieved by changing the radius of each zone of t... A method for obtaining small bottle light beams, e.g. 0.92λ×0.4λ, in a high numerical-aperture lens system is proposed and numerically demonstrated. This can be achieved by changing the radius of each zone of the binary element and polarization rotation angle of the cylindrically polarized vectorial vortex beam. It is found that the transversal and axial sizes of this bottle beam are equal to about 0.92λ and 0.4λ, respectively. In addition, the connection between angular momentum and topological Pancharatnam charge is also shown. 展开更多
关键词 THERMOELECTRIC half-Heusler compounds thermal conductivity
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Zinc Borohydride-Ionic Liquid: Stable and Efficient System for Reductive Reaction of Aldehydes with Primary Amines to Corresponding Secondary Amines 被引量:3
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作者 NIAN Bao-yi XU Gang +1 位作者 WU Jiang-ping YANG Li-rong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第1期120-122,共3页
Ionic liquids(ILs) are attracting much attention in various fields of chemical synthesis, electrochemical applications, liquid-liquid extractions, as well as biotransformations. Among those fields, the application o... Ionic liquids(ILs) are attracting much attention in various fields of chemical synthesis, electrochemical applications, liquid-liquid extractions, as well as biotransformations. Among those fields, the application of ILs as the potential green solvent for a wide variety of synthetic processes is an area of intense researches. High yield, high selectivity, and good catalytic charac-teristics have usually been achieved. After the isolation of products, ILs can usually be recovered and recycled many times by simple treating procedures, such as, filtration, extraction, and dryness. 展开更多
关键词 Ionic liquid Zinc borohydride Reductive arnination BMImBF4
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Modeling and Analysis the Effects of EMP on the Balise System 被引量:3
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作者 Zhiwei Gao Shuai Zhang +1 位作者 Li Hao Ning Cao 《Computers, Materials & Continua》 SCIE EI 2019年第3期859-878,共20页
Balise system is one kind of high-rate point-mode data transmission equipment.It plays an indispensable role in Chinese Train Control System(CTCS),and it has been immigrated and widely used for passenger dedicated lin... Balise system is one kind of high-rate point-mode data transmission equipment.It plays an indispensable role in Chinese Train Control System(CTCS),and it has been immigrated and widely used for passenger dedicated lines and high-speed lines.Thus,its working conditions directly affect train operation safety.However,the balise information transmission system(BITS)is based on the principle of electromagnetic induction,and the communication process is susceptible to external electromagnetic interference.Therefore,it is vital to study the influence of transient signal interference on the balise system.This paper builds the up-link model between the vehicle antena and the balise,and verifies the model’s correctness using finite-difference time-domain method and electromagnetic field theory.This paper analyzes the effect of electromagnetic pulses on the transponder’s uplink and simulates the coupled current under irradiation.The spectral distribution of the three types of pulse interference is analyzed according to relevant standards.Strong electromagnetic pulses have a strong energy distribution in the working frequency band of the up-link,which will generate in-band interference and bit errors.It will affect the balise communication and threaten the safety of train operation.As we know we are the first to analyze the effects of EMP on Chinese BITS,which will lay a foundation for the research of electromagnetic anti-interference or protection to highspeed railway. 展开更多
关键词 Balise system BTM EMP electromagnetic anti-interference.
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Effects of Soluble Ions on Hydration of Calcined Flue Gas Desulphurization Gypsum 被引量:3
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作者 Fu-xing Lin Yan-chi Zhong +3 位作者 Shu-feng Yan Bi-fan Lin Jian-hua Wang Zhi-zhong Su 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第6期764-768,I0003,共6页
The influence of various water soluble cations(K^+,Na^+,Ca^2+,Mg^2+)on the hydration of calcined flue gas desulphurization gypsum was investigated.The results show that all cations but Ca^2+can accelerate the hydratio... The influence of various water soluble cations(K^+,Na^+,Ca^2+,Mg^2+)on the hydration of calcined flue gas desulphurization gypsum was investigated.The results show that all cations but Ca^2+can accelerate the hydration of bassanite.The final crystal size is not largely influenced by different salts,except for Na^+,where the giant crystal with length of>130μm is observed.Current study clarifies the influence of different ions on the hydration of bassanite,which could provide sufficient guide for the pre-treatment of original flue gas desulphurization gypsum before actual application. 展开更多
关键词 BASSANITE Flue gas desulphurization HYDRATION Soluble ions
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Tightly Focusing of Circularly Polarized Vortex Beams through a Uniaxial Birefringent Crystal 被引量:1
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作者 饶连周 王宗篪 郑晓霞 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第9期3223-3226,共4页
Under the approximation of small birefringence, the properties of circularly polarized vortex beams tightly focused through a uniaxial birefringent crystal are studied. With the proper combination of the topological c... Under the approximation of small birefringence, the properties of circularly polarized vortex beams tightly focused through a uniaxial birefringent crystal are studied. With the proper combination of the topological charge and the birefringence, the small focus, the small bottle beam and the inverse c-shaped intensity profile can be obtained. The effects of the focal shift and the Strehl ratio on the birefringence are analysed. A relation between angular momentum (included spin and orbital) and topological Pancharatnam charge is also presented. 展开更多
关键词 the power-law exponents PRECIPITATION durative abrupt precipitation change
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Zinc extraction from sewage sludge with [S,S]-EDDS 被引量:1
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作者 张丽华 张华 《Journal of Central South University》 SCIE EI CAS 2012年第12期3546-3550,共5页
An environmentally friendly biodegradable chelant,[S,S]-ethylenediaminedisuccinic acid(EDDS),was used to separate heavy metals from sewage sludge based on chemical extraction technology.The extraction of zinc from sew... An environmentally friendly biodegradable chelant,[S,S]-ethylenediaminedisuccinic acid(EDDS),was used to separate heavy metals from sewage sludge based on chemical extraction technology.The extraction of zinc from sewage sludge with an aqueous solution of EDDS was studied under various conditions.It is found that the extraction efficiency of zinc using EDDS is equivalent to that using ethylenediaminetetraacetic acid(EDTA)at the molar ratio of chelant to total heavy metals of 1:1 over pH range of 5-9.EDDS is capable of extracting zinc from the sludge.The extraction efficiency is improved obviously and reaches a higher value within pH range from 3 to 10.The extraction efficiency maintains at about 65% when pH≥4.5 and the ratio of 10:1.By comparing the species contents of the zinc in sewage sludge before and after the extraction,it is found that the extracted zinc mainly comes from the acid soluble,reducible and oxidizable fractions. 展开更多
关键词 ZINC [S S]-ethylenediaminedisuccinic acid EXTRACTION sewage sludge chelant biodegradablility
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Synthesis, Crystal Structure and Characterization of the Host-guest Type UOF 被引量:5
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作者 吴红燕 李浩宏 陈之荣 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第4期679-688,共10页
A new uranium(Ⅵ)-polycarboxylate framework with honeycomb(6,3) nets {[Zn(phen)_2(H_2O)_2][(UO_2)_2(BDC)_3]·2H_2O}n(1, BDC = benzene-1,4-dicarboxylate) was hydrotherrmally synthesized by the reactio... A new uranium(Ⅵ)-polycarboxylate framework with honeycomb(6,3) nets {[Zn(phen)_2(H_2O)_2][(UO_2)_2(BDC)_3]·2H_2O}n(1, BDC = benzene-1,4-dicarboxylate) was hydrotherrmally synthesized by the reactions of Zn(NO_3)_2·6H_2O with phenanthroine, UO_2(NO_3)_2·6H_2O and benzene-1,4-dicarboxylate. The complex was structurally characterized by FT-IR spectroscopy, powder XRD and X-ray single-crystal diffraction. Crystal data for 1: monoclinic, space group Cc with M_r = 1522.19, a = 14.9385(10), b = 20.4922(13), c = 15.9728(10) ?, β = 100.1240(10)°, V = 4813.5(5) ?~3, Z = 4, D_c = 2.100 g?cm^(–3), μ = 7.293 mm^(–1), F(000) = 2872, the final R = 0.0224 and w R= 0.0677 for 6522 observed reflections with I 〉 2σ(I). Hydrogen bonds and π-π stacking interactions contribute to the structural extension and stabilization. Experimental band gap of about 3.57 e V indicates its broad gap semiconductor nature. UV-Vis spectra and solid-state luminescence were discussed in detail. The compound exhibits photocatalytic activities for the degradation of rhodamine B. 展开更多
关键词 uranium hydrothermally synthesized crystal structure UV-vis spectra photoluminescent properties
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Prediction of heat transfer of nanofluid on critical heat flux based on fractal geometry 被引量:1
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作者 肖波齐 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第1期344-349,共6页
Analytical expressions for nucleate pool boiling heat transfer of nanofluid in the critical heat flux (CHF) region are derived taking into account the effect of nanoparticles moving in liquid based on the fractal ge... Analytical expressions for nucleate pool boiling heat transfer of nanofluid in the critical heat flux (CHF) region are derived taking into account the effect of nanoparticles moving in liquid based on the fractal geometry theory. The proposed fractal model for the CHF of nanofluid is explicitly related to the average diameter of the nanoparticles, the volumetric nanoparticle concentration, the thermal conductivity of nanoparticles, the fractal dimension of nanoparticles, the fractal dimension of active cavities on the heated surfaces, the temperature, and the properties of the fluid. It is found that the CHF of nanofluid decreases with the increase of the average diameter of nanoparticles. Each parameter of the proposed formulas on CHF has a clear physical meaning. The model predictions are compared with the existing experimental data, and a good agreement between the model predictions and experimental data is found. The validity of the present model is thus verified. The proposed fractal model can reveal the mechanism of heat transfer in nanofluid. 展开更多
关键词 NANOFLUID fractal geometry heat transfer
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具有结构不确定性一般非线形系统通过鲁棒无源的反馈镇定 被引量:1
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作者 蔡秀珊 韩正之 寇春海 《自动化学报》 EI CSCD 北大核心 2005年第6期839-843,共5页
The general nonlinear system with structural uncertainty is dealt with and necessary conditions for it to be robust passivity are derived. From these necessary conditions, sufficient conditions of zero state detectabi... The general nonlinear system with structural uncertainty is dealt with and necessary conditions for it to be robust passivity are derived. From these necessary conditions, sufficient conditions of zero state detectability are deduced. Based on passive systems theory and the technique of feedback equivalence, sufficient conditions for it to be locally (globally) asymptotically stabilized via smooth state feedback are developed. A smooth state feedback control law can be constructed explicitly to locally (globally) stabilize the equilibrium of the closed-loop system. Simulation example shows the effectiveness of the method. 展开更多
关键词 结构不确定性 非线形系统 鲁棒无源控制 反馈稳定
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Spatial Correlation Properties of Tightly Focused J0-Correlated Azimuthally Polarized Vortex Beams 被引量:1
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作者 RAO Lian-Zhou LIN Hui-Chuan SUN Qing-Quan 《Chinese Physics Letters》 SCIE CAS CSCD 2013年第5期89-92,共4页
Based on vectorial Debye diffraction theory, the spatial correlation properties in the focal region of a J0 -correlated azimuthally polarized vortex beam through a high numerical aperture (NA) are analyzed. The expres... Based on vectorial Debye diffraction theory, the spatial correlation properties in the focal region of a J0 -correlated azimuthally polarized vortex beam through a high numerical aperture (NA) are analyzed. The expressions for a pair of points on the axis of symmetry and for a pair of points in the focal plane are derived. It is found that the longitudinal and transverse coherence lengths in the focal region change with the variation in the topological charge and coherence parameter of the vortex field, together with the NA values. In addition, the degree of coherence is shown to possess phase singularities. 展开更多
关键词 VORTEX SYMMETRY TOPOLOGICAL
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Massive Files Prefetching Model Based on LSTM Neural Network with Cache Transaction Strategy 被引量:2
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作者 Dongjie Zhu Haiwen Du +6 位作者 Yundong Sun Xiaofang Li Rongning Qu Hao Hu Shuangshuang Dong Helen Min Zhou Ning Cao 《Computers, Materials & Continua》 SCIE EI 2020年第5期979-993,共15页
In distributed storage systems,file access efficiency has an important impact on the real-time nature of information forensics.As a popular approach to improve file accessing efficiency,prefetching model can fetches d... In distributed storage systems,file access efficiency has an important impact on the real-time nature of information forensics.As a popular approach to improve file accessing efficiency,prefetching model can fetches data before it is needed according to the file access pattern,which can reduce the I/O waiting time and increase the system concurrency.However,prefetching model needs to mine the degree of association between files to ensure the accuracy of prefetching.In the massive small file situation,the sheer volume of files poses a challenge to the efficiency and accuracy of relevance mining.In this paper,we propose a massive files prefetching model based on LSTM neural network with cache transaction strategy to improve file access efficiency.Firstly,we propose a file clustering algorithm based on temporal locality and spatial locality to reduce the computational complexity.Secondly,we propose a definition of cache transaction according to files occurrence in cache instead of time-offset distance based methods to extract file block feature accurately.Lastly,we innovatively propose a file access prediction algorithm based on LSTM neural network which predict the file that have high possibility to be accessed.Experiments show that compared with the traditional LRU and the plain grouping methods,the proposed model notably increase the cache hit rate and effectively reduces the I/O wait time. 展开更多
关键词 Massive files prefetching model cache transaction distributed storage systems LSTM neural network
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A Dynamic Memory Allocation Optimization Mechanism Based on Spark 被引量:2
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作者 Suzhen Wang Shanshan Geng +7 位作者 Zhanfeng Zhang Anshan Ye Keming Chen Zhaosheng Xu Huimin Luo Gangshan Wu Lina Xu Ning Cao 《Computers, Materials & Continua》 SCIE EI 2019年第8期739-757,共19页
Spark is a distributed data processing framework based on memory.Memory allocation is a focus question of Spark research.A good memory allocation scheme can effectively improve the efficiency of task execution and mem... Spark is a distributed data processing framework based on memory.Memory allocation is a focus question of Spark research.A good memory allocation scheme can effectively improve the efficiency of task execution and memory resource utilization of the Spark.Aiming at the memory allocation problem in the Spark2.x version,this paper optimizes the memory allocation strategy by analyzing the Spark memory model,the existing cache replacement algorithms and the memory allocation methods,which is on the basis of minimizing the storage area and allocating the execution area according to the demand.It mainly including two parts:cache replacement optimization and memory allocation optimization.Firstly,in the storage area,the cache replacement algorithm is optimized according to the characteristics of RDD Partition,which is combined with PCA dimension.In this section,the four features of RDD Partition are selected.When the RDD cache is replaced,only two most important features are selected by PCA dimension reduction method each time,thereby ensuring the generalization of the cache replacement strategy.Secondly,the memory allocation strategy of the execution area is optimized according to the memory requirement of Task and the memory space of storage area.In this paper,a series of experiments in Spark on Yarn mode are carried out to verify the effectiveness of the optimization algorithm and improve the cluster performance. 展开更多
关键词 Memory calculation memory allocation optimization cache replacement optimization
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Preparation and characterization of sulfated TiO_2 with rhodium modification used in esterification reaction and decomposition of methyl orange 被引量:3
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作者 Yu Niu Fuying Li +3 位作者 Kai Yang Ting Qiu Renzhang Wang Cheng Lin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第6期767-774,共8页
A unique Rh/TiO2 solid acid catalyst modified with H2S04 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange (MO) in aqueous phase under h... A unique Rh/TiO2 solid acid catalyst modified with H2S04 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange (MO) in aqueous phase under halogen lamp irradiation. For this purpose, rhodium (Rh) nanoparticles were loaded on S02-/Ti02 via the photo-deposition method. It was found that S024-/Rh-Ti02 exhibited stronger catalytic activity than S02-/ Ti02. The new catalysts were characterized by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET), Transmission electron microscopy (TEM) and high-resolution (HRTEM), X-ray photoelectron spec- troscopy (XPS) and Fourier Transform infrared spectroscopy (FrlR). Results from XRD and BET show that S02-/Rh-Ti02 has higher specific surface area and smaller pore size than S02-fri02. The distribution of loaded Rh was found to be uniform with a particle size of 2-4 nm. Data from XPS reveal that Rh primarily exists as Rh~ and Rh3 + in Rh-Ti02 and SO^-/Rh-TiO~. These valence forms of Rh likely contribute to the en- hanced catalytic activity. Furthermore, FT-IR spectra of the catalysts show an abundance of surface hydroxyl groups, which help the formation of hydroxyl radicals and the enhancement of surface acid density. The results show that more acid sites are formed on the sulfated Rh-Ti02, and these acidic sites are largely responsible for improving the catalytic performance. This superior SO]-/Rh-Ti02 catalyst has potential applications in reactions reouirinz efficient acid catalysts, includinz esterification reactions and waste water treatment. 展开更多
关键词 RhodiumEsterification reactionSO2 /Ti02Photo-depositionMethyl orange
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