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基于LOF-FCM算法的船舶航行数据识别
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作者 崔秀芳 林浩涛 +1 位作者 安楠楠 王认认 《船舶工程》 CSCD 北大核心 2024年第S01期488-493,499,共7页
针对传统船舶自动识别系统数据在清洗异常数据和提取停留数据时分别采用不同的识别方式、类型判断阈值需要人为设定、识别效率不佳的局限性,首次提出了一种船舶航行轨迹中停留及异常数据的一体化检测方法。通过分析航行路线的3种数据(... 针对传统船舶自动识别系统数据在清洗异常数据和提取停留数据时分别采用不同的识别方式、类型判断阈值需要人为设定、识别效率不佳的局限性,首次提出了一种船舶航行轨迹中停留及异常数据的一体化检测方法。通过分析航行路线的3种数据(停留、异常和航行)异常因子特征,提出基于LOF-FCM的船舶航行数据、停留数据和异常数据一体化检测算法。实验对3类数据进行了识别,模型识别准确率达到了92.69%,有效提高了异常、停留、航行数据的识别能力。结果表明所提方法可一次性实现AIS数据中3种数据的检测,能高效分离出正常船舶航行数据,具有良好的工程应用价值。 展开更多
关键词 数据清洗 异常数据辨识 自动识别系统(AIS) 模糊C均值(FCM)
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OFDM系统中一种A-MMSE信道估计算法
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作者 叶文伟 《半导体光电》 CAS 北大核心 2024年第2期308-312,共5页
针对正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)系统中最小均方误差(Minimum Mean Squared Error,MMSE)信道估计算法误码率(BER)高的问题,提出一种平均最小均方误差(Averaged-Minimum Mean Squared Error,A-MMSE)... 针对正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)系统中最小均方误差(Minimum Mean Squared Error,MMSE)信道估计算法误码率(BER)高的问题,提出一种平均最小均方误差(Averaged-Minimum Mean Squared Error,A-MMSE)信道估计算法。该算法首先基于802.11n标准而构造了一种新的导频结构,收发两端分别进行降采样和过采样处理,利用已知训练序列和导频获得信道频域响应。仿真结果表明,所提出的A-MMSE信道估计算法与传统的MMSE算法相比,在BER为10^(-3)时,信噪比改善了约8dB。因而所提出的信道估计算法能明显改善系统的BER性能。 展开更多
关键词 正交频分复用系统 导频 最小均方误差 误码率
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El Niño and the AMO Sparked the Astonishingly Large Margin of Warming in the Global Mean Surface Temperature in 2023 被引量:2
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作者 Kexin LI Fei ZHENG +1 位作者 Jiang ZHU Qing-Cun ZENG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第6期1017-1022,共6页
In 2023,the majority of the Earth witnessed its warmest boreal summer and autumn since 1850.Whether 2023 will indeed turn out to be the warmest year on record and what caused the astonishingly large margin of warming ... In 2023,the majority of the Earth witnessed its warmest boreal summer and autumn since 1850.Whether 2023 will indeed turn out to be the warmest year on record and what caused the astonishingly large margin of warming has become one of the hottest topics in the scientific community and is closely connected to the future development of human society.We analyzed the monthly varying global mean surface temperature(GMST)in 2023 and found that the globe,the land,and the oceans in 2023 all exhibit extraordinary warming,which is distinct from any previous year in recorded history.Based on the GMST statistical ensemble prediction model developed at the Institute of Atmospheric Physics,the GMST in 2023 is predicted to be 1.41℃±0.07℃,which will certainly surpass that in 2016 as the warmest year since 1850,and is approaching the 1.5℃ global warming threshold.Compared to 2022,the GMST in 2023 will increase by 0.24℃,with 88%of the increment contributed by the annual variability as mostly affected by El Niño.Moreover,the multidecadal variability related to the Atlantic Multidecadal Oscillation(AMO)in 2023 also provided an important warming background for sparking the GMST rise.As a result,the GMST in 2023 is projected to be 1.15℃±0.07℃,with only a 0.02℃ increment,if the effects of natural variability—including El Niño and the AMO—are eliminated and only the global warming trend is considered. 展开更多
关键词 record-breaking temperature global mean surface temperature El Niño AMO global warming
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Genetics of biochemical attributes regulating morpho-physiology of upland cotton under high temperature conditions 被引量:1
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作者 MAJEED Sajid CHAUDHARY Muhammad Tanees +7 位作者 MUBARIK Muhammad Salman RANA Iqrar Ahmad SHABAN Muhammad TAN Daniel KY JIA Yinhua DU Xiongming HINZE Lori AZHAR Muhammad Tehseen 《Journal of Cotton Research》 CAS 2024年第1期29-44,共16页
Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threaten... Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars. 展开更多
关键词 ACCESSIONS BIOCHEMICAL BREEDING Cotton Generation mean analysis Heat stress
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An Exploratory Study of the Interpersonal Meanings of President Xi’s New Year Speech Based on Appraisal Theory
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作者 LIN Hanzhao 《Cultural and Religious Studies》 2023年第2期84-90,共7页
The research examines President Xi’s 2021 New Year speech with research questions centering around its abundant interpersonal meanings.Through qualitative content analysis,the research finds that it is typical for Ch... The research examines President Xi’s 2021 New Year speech with research questions centering around its abundant interpersonal meanings.Through qualitative content analysis,the research finds that it is typical for Chinese president to frequently use judgment and appreciation resources in reviewing the past year.Even in the face of the pandemic and natural disasters,the overall emotions of the speech remain positive,which corresponds to the forward-looking feature of New Year speech.Significance of the study abounds and future research can investigate how COVID-19 impacts the ideologies conveyed through political leaders’speeches through a comparative lens and how to produce more understandings that can help dismantle stereotypes and discrimination hidden in reports about COVID-19 by using Appraisal Theory critically,systematically,and comprehensively. 展开更多
关键词 Political discourse New Year speech Appraisal Theory Interpersonal meanings COVID-19 pandemic
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Solving Invariant Problem of Cauchy Means Based on Wronskian Determinant
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作者 Yingjun Ni Fen Wang 《Advances in Pure Mathematics》 2024年第7期515-522,共8页
This paper studied the invariance of the Cauchy mean with respect to the arithmetic mean when the denominator functions satisfy certain conditions. The partial derivatives of Cauchy’s mean on the diagonal are obtaine... This paper studied the invariance of the Cauchy mean with respect to the arithmetic mean when the denominator functions satisfy certain conditions. The partial derivatives of Cauchy’s mean on the diagonal are obtained by using the method of Wronskian determinant in the process of solving. Then the invariant equation is solved by using the obtained partial derivatives. Finally, the solutions of invariant equations when the denominator functions satisfy the same simple harmonic oscillator equation or the denominator functions are power functions that have been obtained. 展开更多
关键词 Cauchy Mean Wronskian Determinant Arithmetic Mean Invariant Equation
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A Novel Fractional Dengue Transmission Model in the Presence of Wolbachia Using Stochastic Based Artificial Neural Network
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作者 Zeshan Faiz Iftikhar Ahmed +1 位作者 Dumitru Baleanu Shumaila Javeed 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第5期1217-1238,共22页
The purpose of this research work is to investigate the numerical solutions of the fractional dengue transmission model(FDTM)in the presence of Wolbachia using the stochastic-based Levenberg-Marquardt neural network(L... The purpose of this research work is to investigate the numerical solutions of the fractional dengue transmission model(FDTM)in the presence of Wolbachia using the stochastic-based Levenberg-Marquardt neural network(LM-NN)technique.The fractional dengue transmission model(FDTM)consists of 12 compartments.The human population is divided into four compartments;susceptible humans(S_(h)),exposed humans(E_(h)),infectious humans(I_(h)),and recovered humans(R_(h)).Wolbachia-infected and Wolbachia-uninfected mosquito population is also divided into four compartments:aquatic(eggs,larvae,pupae),susceptible,exposed,and infectious.We investigated three different cases of vertical transmission probability(η),namely when Wolbachia-free mosquitoes persist only(η=0.6),when both types of mosquitoes persist(η=0.8),and when Wolbachia-carrying mosquitoes persist only(η=1).The objective of this study is to investigate the effectiveness of Wolbachia in reducing dengue and presenting the numerical results by using the stochastic structure LM-NN approach with 10 hidden layers of neurons for three different cases of the fractional order derivatives(α=0.4,0.6,0.8).LM-NN approach includes a training,validation,and testing procedure to minimize the mean square error(MSE)values using the reference dataset(obtained by solving the model using the Adams-Bashforth-Moulton method(ABM).The distribution of data is 80% data for training,10% for validation,and,10% for testing purpose)results.A comprehensive investigation is accessible to observe the competence,precision,capacity,and efficiency of the suggested LM-NN approach by executing the MSE,state transitions findings,and regression analysis.The effectiveness of the LM-NN approach for solving the FDTM is demonstrated by the overlap of the findings with trustworthy measures,which achieves a precision of up to 10^(-4). 展开更多
关键词 WOLBACHIA DENGUE neural network vertical transmission mean square error LEVENBERG-MARQUARDT
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Study of the Magnetocaloric Effect in La0.5Sm0.2Sr0.3Mn1-xFexO3 (x = 0 and 0.05) Manganites with the Mean-Field Theory
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作者 Amnah Alofi Salha Khadhraui 《Advances in Materials Physics and Chemistry》 CAS 2024年第7期113-122,共10页
In this paper, the magnetocaloric in La0.5Sm0.2Sr0.3Mn1-xFexO3 compounds with x = 0 (LSSMO) and x = 0.05 (LSSMFO) were simulated using mean field model theory. A strong consistency was observed between the theoretical... In this paper, the magnetocaloric in La0.5Sm0.2Sr0.3Mn1-xFexO3 compounds with x = 0 (LSSMO) and x = 0.05 (LSSMFO) were simulated using mean field model theory. A strong consistency was observed between the theoretical and experimental curves of magnetizations and magnetic entropy changes, −ΔSM(T). Based on the mean-field generated −ΔSM(T), the substantial Temperature-averaged Entropy Change (TEC) values reinforce the appropriateness of these materials for use in magnetic refrigeration technology within TEC (10) values of 1 and 0.57 J∙kg−1∙K−1under 1 T applied magnetic field. 展开更多
关键词 MANGANITES MAGNETIZATION Magnetocaloric Effect Mean Field Model SIMULATION
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Properties of collective flow and pion production in intermediate-energy heavy-ion collisions with a relativistic quantum molecular dynamics model
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作者 Si-Na Wei Zhao-Qing Feng 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第1期155-169,共15页
The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(LQMD.RMF). Using the LQMD.RMF, the properties of collective flow and pion production were investigated sys... The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(LQMD.RMF). Using the LQMD.RMF, the properties of collective flow and pion production were investigated systematically for nuclear reactions with various isospin asymmetries. The directed and elliptic flows of the LQMD.RMF are able to describe the experimental data of STAR Collaboration. The directed flow difference between free neutrons and protons was associated with the stiffness of the symmetry energy, that is, a softer symmetry energy led to a larger flow difference. For various collision energies, the ratio between the π^(-) and π^(+) yields increased with a decrease in the slope parameter of the symmetry energy. When the collision energy was 270 MeV/nucleon, the single ratio of the pion transverse momentum spectra also increased with decreasing slope parameter of the symmetry energy in both nearly symmetric and neutron-rich systems.However, it is difficult to constrain the stiffness of the symmetry energy with the double ratio because of the lack of threshold energy correction on the pion production. 展开更多
关键词 Heavy-ion collision Collective flow Pion production Symmetry energy Relativistic mean field
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Assessing the Performance of a Dynamical Downscaling Simulation Driven by a Bias-Corrected CMIP6 Dataset for Asian Climate
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作者 Zhongfeng XU Ying HAN +4 位作者 Meng-Zhuo ZHANG Chi-Yung TAM Zong-Liang YANG Ahmed M.EL KENAWY Congbin FU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第5期974-988,共15页
In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three... In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three simulations were conducted with a 25-km grid spacing for the period 1980–2014.The first simulation(WRF_ERA5)was driven by the European Centre for Medium-Range Weather Forecasts Reanalysis 5(ERA5)dataset and served as the validation dataset.The original GCM dataset(MPI-ESM1-2-HR model)was used to drive the second simulation(WRF_GCM),while the third simulation(WRF_GCMbc)was driven by the bias-corrected GCM dataset.The bias-corrected GCM data has an ERA5-based mean and interannual variance and long-term trends derived from the ensemble mean of 18 CMIP6 models.Results demonstrate that the WRF_GCMbc significantly reduced the root-mean-square errors(RMSEs)of the climatological mean of downscaled variables,including temperature,precipitation,snow,wind,relative humidity,and planetary boundary layer height by 50%–90%compared to the WRF_GCM.Similarly,the RMSEs of interannual-tointerdecadal variances of downscaled variables were reduced by 30%–60%.Furthermore,the WRF_GCMbc better captured the annual cycle of the monsoon circulation and intraseasonal and day-to-day variabilities.The leading empirical orthogonal function(EOF)shows a monopole precipitation mode in the WRF_GCM.In contrast,the WRF_GCMbc successfully reproduced the observed tri-pole mode of summer precipitation over eastern China.This improvement could be attributed to a better-simulated location of the western North Pacific subtropical high in the WRF_GCMbc after GCM bias correction. 展开更多
关键词 bias correction multi-model ensemble mean dynamical downscaling interannual variability day-to-day variability validation
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Charge self-consistent dynamical mean field theory calculations incombination with linear combination of numerical atomic orbitalsframework based density functional theory
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作者 Xin Qu Peng Xu +6 位作者 Zhiyong Liu Jintao Wang Fei Wang Wei Huang Zhongxin Li Weichang Xu Xinguo Ren 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期62-69,共8页
We present a formalism of charge self-consistent dynamical mean field theory(DMFT)in combination with densityfunctional theory(DFT)within the linear combination of numerical atomic orbitals(LCNAO)framework.We implemen... We present a formalism of charge self-consistent dynamical mean field theory(DMFT)in combination with densityfunctional theory(DFT)within the linear combination of numerical atomic orbitals(LCNAO)framework.We implementedthe charge self-consistent DFT+DMFT formalism by interfacing a full-potential all-electron DFT code with threehybridization expansion-based continuous-time quantum Monte Carlo impurity solvers.The benchmarks on several 3d,4fand 5f strongly correlated electron systems validated our formalism and implementation.Furthermore,within the LCANOframework,our formalism is general and the code architecture is extensible,so it can work as a bridge merging differentLCNAO DFT packages and impurity solvers to do charge self-consistent DFT+DMFT calculations. 展开更多
关键词 dynamical mean field theory density functional theory strongly correlated electrons
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A new method of calculating crown projection area and its comparative accuracy with conventional calculations for asymmetric tree crowns
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作者 Mingrui Zhang Huiquan Bi +1 位作者 Xingji Jin Michael McLean 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第4期171-188,共18页
This paper introduces a new method of calculating crown projection area(CPA),the area of level ground covered by a vertical projection of a tree crown from measured crown radii through numerical interpolation and inte... This paper introduces a new method of calculating crown projection area(CPA),the area of level ground covered by a vertical projection of a tree crown from measured crown radii through numerical interpolation and integration.This novel method and other four existing methods of calculating CPA were compared using detailed crown radius measurements from 30 tall trees of Eucalyptus pilularis variable in crown size,shape,and asymmetry.The four existing methods included the polygonal approach and three ways of calculating CPA as the area of a circle using the arithmetic,geometric and quadratic mean radius.Comparisons were made across a sequence of eight non-consecutive numbers(from 2 to 16)of measured crown radii for each tree over the range of crown asymmetry of the 30 trees through generalized linear models and multiple comparisons of means.The sequence covered the range of the number of crown radii measured for calculating the CPA of a tree in the literature.A crown asymmetry index within the unit interval was calculated for each tree to serve as a normative measure.With a slight overestimation of 2.2%on average and an overall mean error size of 7.9%across the numbers of crown radii that were compared,our new method was the least biased and most accurate.Calculating CPA as a circle using the quadratic mean crown radius was the second best,which had an average overestimation of 4.5%and overall mean error size of 8.8%.These two methods remained by and large unbiased as crown asymmetry increased,while the other three methods showed larger bias of underestimation.For the conventional method of using the arithmetic mean crown radius to calculate CPA as a circle,bias correction factors were developed as a function of crown asymmetry index to delineate the increasing magnitude of bias associated with greater degrees of crown asymmetry.This study reveals and demonstrates such relationships between the accuracy of CPA calculations and crown asymmetry and will help increase awareness among researchers and practitioners on the existence of bias in their CPA calculations and for the need to use an unbiased method in the future.Our new method is recommended for calculating CPA where at least four crown radius measurements per tree are available because that is the minimum number required for its use. 展开更多
关键词 Crown radius measurements Interpolated crown contour Projected crown area Multiple comparisons of means
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Analytical and NumericalMethods to Study the MFPT and SR of a Stochastic Tumor-Immune Model
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作者 Ying Zhang Wei Li +1 位作者 Guidong Yang Snezana Kirin 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2177-2199,共23页
The Mean First-Passage Time (MFPT) and Stochastic Resonance (SR) of a stochastic tumor-immune model withnoise perturbation are discussed in this paper. Firstly, considering environmental perturbation, Gaussian whiteno... The Mean First-Passage Time (MFPT) and Stochastic Resonance (SR) of a stochastic tumor-immune model withnoise perturbation are discussed in this paper. Firstly, considering environmental perturbation, Gaussian whitenoise and Gaussian colored noise are introduced into a tumor growth model under immune surveillance. Asfollows, the long-time evolution of the tumor characterized by the Stationary Probability Density (SPD) and MFPTis obtained in theory on the basis of the Approximated Fokker-Planck Equation (AFPE). Herein the recurrenceof the tumor from the extinction state to the tumor-present state is more concerned in this paper. A moreefficient algorithmof Back-Propagation Neural Network (BPNN) is utilized in order to testify the correction of thetheoretical SPDandMFPT.With the existence of aweak signal, the functional relationship between Signal-to-NoiseRatio (SNR), noise intensities and correlation time is also studied. Numerical results show that both multiplicativeGaussian colored noise and additive Gaussian white noise can promote the extinction of the tumors, and themultiplicative Gaussian colored noise can lead to the resonance-like peak on MFPT curves, while the increasingintensity of the additiveGaussian white noise results in theminimum of MFPT. In addition, the correlation timesare negatively correlated with MFPT. As for the SNR, we find the intensities of both the Gaussian white noise andthe Gaussian colored noise, as well as their correlation intensity can induce SR. Especially, SNR is monotonouslyincreased in the case ofGaussian white noisewith the change of the correlation time.At last, the optimal parametersin BPNN structure are analyzed for MFPT from three aspects: the penalty factors, the number of neural networklayers and the number of nodes in each layer. 展开更多
关键词 Stochastic tumor-immune model mean first-passage time stochastic resonance signal-to-noise ratio back-propagation neural network
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Software Cost Estimation Using Social Group Optimization
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作者 Sagiraju Srinadhraju Samaresh Mishra Suresh Chandra Satapathy 《Computer Systems Science & Engineering》 2024年第6期1641-1668,共28页
This paper introduces the integration of the Social Group Optimization(SGO)algorithm to enhance the accuracy of software cost estimation using the Constructive Cost Model(COCOMO).COCOMO’s fixed coefficients often lim... This paper introduces the integration of the Social Group Optimization(SGO)algorithm to enhance the accuracy of software cost estimation using the Constructive Cost Model(COCOMO).COCOMO’s fixed coefficients often limit its adaptability,as they don’t account for variations across organizations.By fine-tuning these parameters with SGO,we aim to improve estimation accuracy.We train and validate our SGO-enhanced model using historical project data,evaluating its performance with metrics like the mean magnitude of relative error(MMRE)and Manhattan distance(MD).Experimental results show that SGO optimization significantly improves the predictive accuracy of software cost models,offering valuable insights for project managers and practitioners in the field.However,the approach’s effectiveness may vary depending on the quality and quantity of available historical data,and its scalability across diverse project types and sizes remains a key consideration for future research. 展开更多
关键词 Manhattan distance mean magnitude of relative error nature-inspired algorithms project management SGO
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On the Equality of Weighted BajratarevićMeans to Quasi-Arithmetic Means
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作者 Yaxun Yang 《Journal of Applied Mathematics and Physics》 2024年第4期1126-1133,共8页
In this paper, we considered the equality problem of weighted Bajraktarević means with weighted quasi-arithmetic means. Using the method of substituting for functions, we first transform the equality problem into solv... In this paper, we considered the equality problem of weighted Bajraktarević means with weighted quasi-arithmetic means. Using the method of substituting for functions, we first transform the equality problem into solving an equivalent functional equation. We obtain the necessary and sufficient conditions for the equality equation. 展开更多
关键词 Bajraktarević Means Quasi-Arithmetic Means Equality Problem Functional Equation
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基于K均值算法-TOF聚类分析的复合材料板冲击损伤层析研究
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作者 林君 杨乐辉 +4 位作者 赵金玲 李念 裘进浩 赵建平 常乐 《压力容器》 北大核心 2024年第5期12-20,共9页
碳纤维增强型复合材料(CFRP)中的冲击损伤是威胁压力容器结构安全的重要隐患,有必要对CFRP中的冲击损伤进行层析研究,促成CFRP复合材料损伤定量化分析。提出基于K均值算法对超声C扫的飞行时间(TOF)图像进行聚类分析,并结合TOF值确定不... 碳纤维增强型复合材料(CFRP)中的冲击损伤是威胁压力容器结构安全的重要隐患,有必要对CFRP中的冲击损伤进行层析研究,促成CFRP复合材料损伤定量化分析。提出基于K均值算法对超声C扫的飞行时间(TOF)图像进行聚类分析,并结合TOF值确定不同簇所在层,对CFRP冲击损伤进行逐层定量化分析。同时,分析了冲击损伤的TOF图像,验证了基于K均值算法-TOF聚类分析的冲击损伤层析方法,并进一步通过水浸超声C扫试验获得多组试验数据,指出K均值聚类中簇的总数K为铺层总数的1.25倍即可满足损伤逐层分析,实现了不同铺层总数CFRP层合板冲击损伤的层析研究。TOF聚类分析方法可以直接对CFRP层合板各铺层的冲击损伤进行定量化,具有一定的工程意义。 展开更多
关键词 碳纤维增强型复合材料(CFRP) 冲击损伤 K均值算法 Tof聚类分析
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A Cognitive Psychological Study on the Acquisition of Chinese Word’s Coloring Meaning--Chinese as a Second Language
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作者 LIU Yan 《Sino-US English Teaching》 2024年第5期217-221,共5页
Lexical meaning mainly includes rational meaning,grammatical meaning,and coloring meaning.Mastering the coloring meaning of vocabulary is of great significance for foreign students to use Chinese vocabulary correctly.... Lexical meaning mainly includes rational meaning,grammatical meaning,and coloring meaning.Mastering the coloring meaning of vocabulary is of great significance for foreign students to use Chinese vocabulary correctly.This study mainly examines the psychological mechanism of Chinese second language learners mastering the coloring meaning of words,examines the psychological characteristics of students mastering the color meaning of words from the perspectives of second language learning theory and cognitive theory,establishes a cognitive schema for coloring meaning learning,and proposes corresponding learning models and teaching strategies. 展开更多
关键词 Chinese vocabulary acquisition coloring meaning COGNITION
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Target acquisition performance in the presence of JPEG image compression
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作者 Boban Bondzulic Nenad Stojanovic +3 位作者 Vladimir Lukin Sergey A.Stankevich Dimitrije Bujakovic Sergii Kryvenko 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期30-41,共12页
This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the image... This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the image.Four new clutter metrics based on image quality assessment are introduced,among which the Haar wavelet-based perceptual similarity index,known as HaarPSI,provides the best target acquisition prediction results.It is shown that the similarity between the target and the background at the boundary between visually lossless and visually lossy compression does not change significantly compared to the case when an uncompressed image is used.In future work,through subjective tests,it is necessary to check whether this presence of compression at the threshold of just noticeable differences will affect the human target acquisition performance.Similarity values are compared with the results of subjective tests of the well-known target Search_2 database,where the degree of agreement between objective and subjective scores,measured through linear correlation,reached a value of 90%. 展开更多
关键词 JPEG compression Target acquisition performance Image quality assessment Just noticeable difference Probability of target detection Target mean searching time
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Performance Analysis of ZF and RZF in Low-Resolution ADC/DAC Massive MIMO Systems
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作者 Talha Younas Shen Jin +4 位作者 Muluneh Mekonnen Gao Mingliang Saqib Saleem Sohaib Tahir Mahrukh Liaqat 《China Communications》 SCIE CSCD 2024年第8期115-126,共12页
Large number of antennas and higher bandwidth usage in massive multiple-input-multipleoutput(MIMO)systems create immense burden on receiver in terms of higher power consumption.The power consumption at the receiver ra... Large number of antennas and higher bandwidth usage in massive multiple-input-multipleoutput(MIMO)systems create immense burden on receiver in terms of higher power consumption.The power consumption at the receiver radio frequency(RF)circuits can be significantly reduced by the application of analog-to-digital converter(ADC)of low resolution.In this paper we investigate bandwidth efficiency(BE)of massive MIMO with perfect channel state information(CSI)by applying low resolution ADCs with Rician fadings.We start our analysis by deriving the additive quantization noise model,which helps to understand the effects of ADC resolution on BE by keeping the power constraint at the receiver in radar.We also investigate deeply the effects of using higher bit rates and the number of BS antennas on bandwidth efficiency(BE)of the system.We emphasize that good bandwidth efficiency can be achieved by even using low resolution ADC by using regularized zero-forcing(RZF)combining algorithm.We also provide a generic analysis of energy efficiency(EE)with different options of bits by calculating the energy efficiencies(EE)using the achievable rates.We emphasize that satisfactory BE can be achieved by even using low-resolution ADC/DAC in massive MIMO. 展开更多
关键词 low-bit analog-digital converter massive(multiple-input-multiple-output)MIMO minimum mean square error(MMSE) regularized zero forcing zero forcing
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Digital Literacy in the Rural Environment of Rivers State, Nigeria
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作者 Priye E.Iyalla-Amadi 《Sino-US English Teaching》 2024年第2期83-88,共6页
While literacy can generally be defined as the basic ability to read,write,and also count,digital literacy can be described as the ability to perform all these tasks using electronic means.These means would include mo... While literacy can generally be defined as the basic ability to read,write,and also count,digital literacy can be described as the ability to perform all these tasks using electronic means.These means would include modern electronic gadgets,such as mobile phones,tablets,computers,kindle books,and the like.To be digitally literate would therefore require the existence of modern technologies such as internet facilities that would make it possible to access online reading and writing.The rural environment,particularly in developing areas,is usually characterised by a seeming lack of modern amenities and even worse,digital internet networks.Yet,those who live in the rural areas of Rivers State belong to the modern digital era and deserve to be digitally literate.This paper examines the prerequisites for digital literacy and explores how these can be achieved for citizens who inhabit the rural areas of an industrially-nascent state like Rivers State. 展开更多
关键词 digital literacy electronic means internet networks rural areas
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