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Acoustic stop bands in almost-periodic and weakly randomized stratified media:perturbation analysis
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作者 S.Guenneau A.B.Movchan +1 位作者 N.V.Movchan J.Trebicki 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第5期549-556,共8页
In this paper, we analyze the effect of both deter- ministic and random perturbations of a regular multi-layered elastic structure on its stop band properties. The tool of choice is the transfer matrix method, which i... In this paper, we analyze the effect of both deter- ministic and random perturbations of a regular multi-layered elastic structure on its stop band properties. The tool of choice is the transfer matrix method, which is both versatile and easy to implement. In both cases, we find that the stop-bands widen. We observe the appearance of very narrow pass-bands within the stop-bands, which can be observed in other instances in optics. 展开更多
关键词 Transmission problem Small random perturbations Stop bands
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Small Random Perturbations of One-Dimensional Diffusion Processes
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作者 Xi Fubao Department of Applied Mathematics, Beijing Institute of Technology, Beijing 100081, China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 1998年第1期35-40,共6页
In the present paper we consider the small random perturbations of one-dimensional diffosion processes. By virtue of stochastic analysis methods, we investigate the asymptotics of the mean exit times and probabilistic... In the present paper we consider the small random perturbations of one-dimensional diffosion processes. By virtue of stochastic analysis methods, we investigate the asymptotics of the mean exit times and probabilistical estimates of the exit times as the perturbations tend to zero. 展开更多
关键词 Diffusion processes Small random perturbations Exit times
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ANALYSIS OF A SUSCEPTIBLE-EXPOSEDINFECTED EPIDEMIC MODEL WITH RANDOM PERTURBATION AND VARYING POPULATION SIZE
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作者 Lihong Chen Fengying Wei 《Annals of Applied Mathematics》 2017年第2期130-138,共9页
In this paper, we study a type of susceptible-exposed-infected(SEI) epidemic model with varying population size and introduce the random perturbation of the constant contact rate into the SEI epidemic model due to t... In this paper, we study a type of susceptible-exposed-infected(SEI) epidemic model with varying population size and introduce the random perturbation of the constant contact rate into the SEI epidemic model due to the universal existence of fluctuations. Under some moderate conditions, the density of the exposed and the infected individuals exponentially approaches zero almost surely are derived. Furthermore, the stochastic SEI epidemic model admits a stationary distribution around the endemic equilibrium, and the solution is ergodic. Some numerical simulations are carried out to demonstrate the efficiency of the main results. 展开更多
关键词 varying population size random perturbation SEI epidemic model stationary distribution
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Time Series of Random Macro-price and Application
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作者 耿显民 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第1期144-155,共12页
This paper tries to utilize the methods of stochastic analysis and matrix analysis to research the existential problem of price series. By using the means of time series analysis, the input-output, Markov processes an... This paper tries to utilize the methods of stochastic analysis and matrix analysis to research the existential problem of price series. By using the means of time series analysis, the input-output, Markov processes and the modern matrix analysis, the limiting problem of price balance and vibration in stochastic economic environment has been researched, and surprising conclusions obtained are as following: the probability that the economic collapse time is equal ∞ is 0. 展开更多
关键词 input-output coefficient matrix economic collapse time maximum eigne value random perturbation Markov process
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Privacy-Preserving Recommendation Based on Kernel Method in Cloud Computing 被引量:1
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作者 Tao Li Qi Qian +2 位作者 Yongjun Ren Yongzhen Ren Jinyue Xia 《Computers, Materials & Continua》 SCIE EI 2021年第1期779-791,共13页
The application field of the Internet of Things(IoT)involves all aspects,and its application in the fields of industry,agriculture,environment,transportation,logistics,security and other infrastructure has effectively... The application field of the Internet of Things(IoT)involves all aspects,and its application in the fields of industry,agriculture,environment,transportation,logistics,security and other infrastructure has effectively promoted the intelligent development of these aspects.Although the IoT has gradually grown in recent years,there are still many problems that need to be overcome in terms of technology,management,cost,policy,and security.We need to constantly weigh the benefits of trusting IoT products and the risk of leaking private data.To avoid the leakage and loss of various user data,this paper developed a hybrid algorithm of kernel function and random perturbation method based on the algorithm of non-negative matrix factorization,which realizes personalized recommendation and solves the problem of user privacy data protection in the process of personalized recommendation.Compared to non-negative matrix factorization privacy-preserving algorithm,the new algorithm does not need to know the detailed information of the data,only need to know the connection between each data;and the new algorithm can process the data points with negative characteristics.Experiments show that the new algorithm can produce recommendation results with certain accuracy under the premise of preserving users’personal privacy. 展开更多
关键词 IOT kernel method PRIVACY-PRESERVING personalized recommendation random perturbation
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Seismic response evaluation of the impact of corrosion on buried pipelines based on the Markov process
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作者 Liu Wei Li Jie 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第3期295-303,共9页
Water distribution and gas supply systems are among the infrastructure systems that have many buried steel pipelines. Corrosion gradually appears inside and outside of the pipe walls over the service life of these pip... Water distribution and gas supply systems are among the infrastructure systems that have many buried steel pipelines. Corrosion gradually appears inside and outside of the pipe walls over the service life of these pipelines, the corrosion is primarily caused by the surrounding soil and the materials that flow through the pipelines. However, due to the uncertainty of the characteristics of the soil and materials, the size of the corrosion region is a stochastic variable. In this paper, using a homogeneous Markov process, a model is presented to simulate the occurrence of corrosion. Then, in combinations with a linear corrosion development model, the probability density function of the pipeline area corrosion percentage is derived. Based on the corrosion model, the pipeline seismic displacements and stresses are predicted. Furthermore, using the random perturbation approach, the mean and variance of the pipeline seismic response are given. To illustrate the validity of the proposed approach, a 200-meter long pipeline is numerically investigated and its random seismic response is obtained. 展开更多
关键词 PIPELINE CORROSION homogeneous Markov process elastic foundation beam random perturbation approach
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Global Optimization Using Diffusion Perturbations with Large Noise Intensity
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作者 G. Yin K. Yin 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2006年第4期529-542,共14页
This work develops an algorithm for global optimization. The algorithm is of gradient ascent type and uses random perturbations. In contrast to the annealing type procedures, the perturbation noise intensity is large.... This work develops an algorithm for global optimization. The algorithm is of gradient ascent type and uses random perturbations. In contrast to the annealing type procedures, the perturbation noise intensity is large. We demonstrate that by properly varying the noise intensity, approximations to the global maximum can be achieved. We also show that the expected time to reach the domain of attraction of the global maximum, which can be approximated by the solution of a boundary value problem, is finite. Discrete-time algorithms are proposed; recursive algorithms with occasional perturbations involving large noise intensity are developed. Numerical examples are provided for illustration. 展开更多
关键词 Global optimization random perturbation DIFFUSION
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Ergodic stationary distribution of two stochastic tuberculosis models with imperfect vaccination and early and late latency 被引量:1
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作者 Qian Jiang Zhijun Liu 《International Journal of Biomathematics》 SCIE 2023年第6期27-56,共30页
This contribution probes into ergodic stationary distribution for two stochastic SVELIT(susceptible-vaccinated-early latent-late latent-infective-treated)tuberculosis(TB)models to observe the impact of white noises an... This contribution probes into ergodic stationary distribution for two stochastic SVELIT(susceptible-vaccinated-early latent-late latent-infective-treated)tuberculosis(TB)models to observe the impact of white noises and color noises on TB control in random environments.We first investigate the existence and uniqueness of ergodic stationary distribution(EUESD)for the autonomous SVELIT model subject to white noises via the proper Lyapunov functions,and suficient conditions on the extinction of disease are acquired.Next,sufficient conditions for the EUESD and the extinction of disease for the SVELIT model with Markov switching are also established.Eventually,some numerical examples validate the theoretical findings.What's more,it has been observed that higher amplitude noises may lead to the eradication of TB,which is conducive to TB control. 展开更多
关键词 TB models random perturbations Markov switching ergodic stationary distribution EXTINCTION
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High-order numerical method for the derivative nonlinear Schrodinger equation 被引量:1
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作者 Shu-Cun Li Xiang-Gui Li +1 位作者 Jun-Jie Cao Wen-Bo Li 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2017年第1期258-270,共13页
In this work,a fourth-order numerical scheme in space and two second-order numerical schemes in both time and space are proposed for the derivative nonlinear Schrodinger equation.We verify the mass conservation for th... In this work,a fourth-order numerical scheme in space and two second-order numerical schemes in both time and space are proposed for the derivative nonlinear Schrodinger equation.We verify the mass conservation for the two-level implicit scheme.The influence on the soliton solution by adding a small random perturbation to the initial condition is discussed.The numerical experiments are given to test the accuracy order for different schemes,respectively.We also test the conservative property of mass and Hamiltonian for these schemes from the numerical point of view. 展开更多
关键词 Derivative nonlinear Schrodinger equation finite difference soliton solution random perturbation
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Dynamic Behaviour of Oilfield ‘A’ Form Derricks
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作者 胡少伟 聂建国 《Tsinghua Science and Technology》 SCIE EI CAS 2001年第1期57-62,共6页
This paper analyses the natural frequencies and modes of ‘A’ form derricks. Using the random perturbative finite element methods, the first-order and second-order sensitivities are calculated when several structural... This paper analyses the natural frequencies and modes of ‘A’ form derricks. Using the random perturbative finite element methods, the first-order and second-order sensitivities are calculated when several structural parameters of elements are changed randomly. The expressions of the random structural eigenvalues of ‘A’ form derricks are given. The results and conclusions are valuable for designing new oilfield derricks in the future. 展开更多
关键词 A’ form derricks dynamic characteristics random perturbation sensitivity
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LONG-TERM DYNAMIC ANALYSIS OF ENDANGERED SPECIES WITH STAGE-STRUCTURE AND MIGRATIONS IN POLLUTED ENVIRONMENTS
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作者 Fangfang Liu Kexin Wang Fengying Wei 《Annals of Applied Mathematics》 2020年第1期48-72,共25页
We propose a stochastic stage-structured single-species model with migrations and hunting within a polluted environment,where the species is separated into two groups:the immature and the mature,which migrates from on... We propose a stochastic stage-structured single-species model with migrations and hunting within a polluted environment,where the species is separated into two groups:the immature and the mature,which migrates from one patch to another with different migration rates.By constructing a Lyapunov function,together with stochastic analysis approach,the stochastic single-species model admits a unique global positive solution.We then utilize the comparison theorem of stochastic differential equations to investigate the extinction and persistence of solution to stochastic single-species model.The main results indicate that the species densities all depend on the intensities of random perturbations within both patches.As a consequence,we further provide several strategies for protecting endangered species within protected and unprotected patches. 展开更多
关键词 protection zones STAGE-STRUCTURE random perturbations MIGRATION extinction and persistence
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