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Well-posedness and exponential stability of a dynamic frictionless contact problem with normal compliance and infinite memory
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作者 Imane Ouakil Benyattou Benabderrahmane Yamna Boukhatem 《Applied Mathematics(A Journal of Chinese Universities)》 2026年第1期99-119,共21页
A model for dynamic frictionless contact between a viscoelastic body and foundation is considered.The viscoelastic constitutive law is assumed to be nonlinear and the contact is modelled with the normal compliance con... A model for dynamic frictionless contact between a viscoelastic body and foundation is considered.The viscoelastic constitutive law is assumed to be nonlinear and the contact is modelled with the normal compliance condition.We obtain the well-posedness using nonlinear semigroup theory arguments.Moreover,the exponential stability result of the solution is shown by using the energy method to produce a suitable Lyapunov function. 展开更多
关键词 dynamic process viscoelastic body normal compliance nonlinear semigroup theory exponential stability
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An efficient uncertainty propagation method for nonlinear dynamics with distribution-free P-box processes 被引量:1
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作者 Licong ZHANG Chunna LI +3 位作者 Hua SU Yuannan XU Andrea Da RONCH Chunlin GONG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第12期116-138,共23页
The distribution-free P-box process serves as an effective quantification model for timevarying uncertainties in dynamical systems when only imprecise probabilistic information is available.However,its application to ... The distribution-free P-box process serves as an effective quantification model for timevarying uncertainties in dynamical systems when only imprecise probabilistic information is available.However,its application to nonlinear systems remains limited due to excessive computation.This work develops an efficient method for propagating distribution-free P-box processes in nonlinear dynamics.First,using the Covariance Analysis Describing Equation Technique(CADET),the dynamic problems with P-box processes are transformed into interval Ordinary Differential Equations(ODEs).These equations provide the Mean-and-Covariance(MAC)bounds of the system responses in relation to the MAC bounds of P-box-process excitations.They also separate the previously coupled P-box analysis and nonlinear-dynamic simulations into two sequential steps,including the MAC bound analysis of excitations and the MAC bounds calculation of responses by solving the interval ODEs.Afterward,a Gaussian assumption of the CADET is extended to the P-box form,i.e.,the responses are approximate parametric Gaussian P-box processes.As a result,the probability bounds of the responses are approximated by using the solutions of the interval ODEs.Moreover,the Chebyshev method is introduced and modified to efficiently solve the interval ODEs.The proposed method is validated based on test cases,including a duffing oscillator,a vehicle ride,and an engineering black-box problem of launch vehicle trajectory.Compared to the reference solutions based on the Monte Carlo method,with relative errors of less than 3%,the proposed method requires less than 0.2% calculation time.The proposed method also possesses the ability to handle complex black-box problems. 展开更多
关键词 nonlinear dynamics Uncertainty propagation Imprecise probability Distribution-free P-box processes Chebyshev method
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Nonlinear dynamics and coupling effect of libration and vibration of tethered space robot in deorbiting process
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作者 王班 郭吉丰 +1 位作者 冯吉根 王剑 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1095-1105,共11页
In order to control the growth of space debris,a novel tethered space robot(TSR) was put forward.After capture,the platform,tether,and target constituted a tethered combination system.General nonlinear dynamics of the... In order to control the growth of space debris,a novel tethered space robot(TSR) was put forward.After capture,the platform,tether,and target constituted a tethered combination system.General nonlinear dynamics of the tethered combination system in the post-capture phase was established with the consideration of the attitudes of two spacecrafts and the quadratic nonlinear elasticity of the tether.The motion law of the tethered combination in the deorbiting process with different disturbances was simulated and discussed on the premise that the platform was only controlled by a constant thrust force.It is known that the four motion freedoms of the tethered combination are coupled with each other in the deorbiting process from the simulation results.A noticeable phenomenon is that the tether longitudinal vibration does not decay to vanish even under the large tether damping with initial attitude disturbances due to the coupling effect.The approximate analytical solutions of the dynamics for a simplified model are obtained through the perturbation method.The condition of the inter resonance phenomenon is the frequency ratio λ_1=2.The case study shows good accordance between the analytical solutions and numerical results,indicating the effectiveness and correctness of approximate analytical solutions. 展开更多
关键词 tethered space robot general nonlinear dynamics deorbiting process perturbation method inter resonance phenomenon
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Effect of Nonlinear Dynamic Process on Formation and Breakdown of Blocking
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作者 张佩 倪允琪 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1991年第1期41-50,共10页
With the L-P approximate method(variation of parameter method), a barotropic channel model in β-plane is used to study the effect of nonlinear interaction between two waves with different scales on the formation of b... With the L-P approximate method(variation of parameter method), a barotropic channel model in β-plane is used to study the effect of nonlinear interaction between two waves with different scales on the formation of blocking. The approximate analytical solution, which can describe the process of the blocking formation, maintenance and breakdown, has been obtained by using the method of aproximate expansion. The importance of nonlinear interaction between two waves with different scales is stressed in the solution. The result suggests that the nonlinear interaction is the main dynamic process of the blocking formation. Some required conditions of blocking formation are also discussed. 展开更多
关键词 PRO Effect of nonlinear dynamic process on Formation and Breakdown of Blocking
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Gaussian Sum PHD Filtering Algorithm for Nonlinear Non-Gaussian Models 被引量:14
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作者 尹建君 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第4期341-351,共11页
A new multi-target filtering algorithm, termed as the Gaussian sum probability hypothesis density (GSPHD) filter, is proposed for nonlinear non-Gaussian tracking models. Provided that the initial prior intensity of ... A new multi-target filtering algorithm, termed as the Gaussian sum probability hypothesis density (GSPHD) filter, is proposed for nonlinear non-Gaussian tracking models. Provided that the initial prior intensity of the states is Gaussian or can be identified as a Gaussian sum, the analytical results of the algorithm show that the posterior intensity at any subsequent time step remains a Gaussian sum under the assumption that the state noise, the measurement noise, target spawn intensity, new target birth intensity, target survival probability, and detection probability are all Gaussian sums. The analysis also shows that the existing Gaussian mixture probability hypothesis density (GMPHD) filter, which is unsuitable for handling the non-Gaussian noise cases, is no more than a special case of the proposed algorithm, which fills the shortage of incapability of treating non-Gaussian noise. The multi-target tracking simulation results verify the effectiveness of the proposed GSPHD. 展开更多
关键词 signal processing Gaussian sum probability hypothesis density SIMULATION nonlinear non-gaussian TRACKING
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Prediction of COVID-19 Outbreak in China and Optimal Return Date for University Students Based on Propagation Dynamics 被引量:3
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作者 HUANG Ganyu PAN Qiaoyi +2 位作者 ZHAO Shuangying GAO Yucen GAO Xiaofeng 《Journal of Shanghai Jiaotong university(Science)》 EI 2020年第2期140-146,共7页
On 12 December 2019,a novel coronavirus disease,named COVID-19,began to spread around the world from Wuhan,China.It is useful and urgent to consider the future trend of this outbreak.We establish the 4+1 penta-group m... On 12 December 2019,a novel coronavirus disease,named COVID-19,began to spread around the world from Wuhan,China.It is useful and urgent to consider the future trend of this outbreak.We establish the 4+1 penta-group model to predict the development of the COVID-19 outbreak.In this model,we use the collected data to calibrate the parameters,and let the recovery rate and mortality change according to the actual situation.Furthermore,we propose the BAT model,which is composed of three parts:simulation of the return rush(Back),analytic hierarchy process(AHP)method,and technique for order preference by similarity to an ideal solution(TOPSIS)method,to figure out the best return date for university students.We also discuss the impacts of some factors that may occur in the future,such as secondary infection,emergence of effective drugs,and population flow from Korea to China. 展开更多
关键词 EPIDEMIC dynamics model nonlinear least SQUARES analytic hierarchy process(AHP) technique for order PREFERENCE by similarity to an ideal solution(TOPSIS)
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A direct probabilistic approach to solve state equations for nonlinear systems under random excitation 被引量:1
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作者 Zheng Lv Zhiping Qiu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第5期941-958,共18页
In this paper, a direct probabilistic approach(DPA) is presented to formulate and solve moment equations for nonlinear systems excited by environmental loads that can be either a stationary or nonstationary random p... In this paper, a direct probabilistic approach(DPA) is presented to formulate and solve moment equations for nonlinear systems excited by environmental loads that can be either a stationary or nonstationary random process.The proposed method has the advantage of obtaining the response's moments directly from the initial conditions and statistical characteristics of the corresponding external excitations. First, the response's moment equations are directly derived based on a DPA, which is completely independent of the It?/filtering approach since no specific assumptions regarding the correlation structure of excitation are made.By solving them under Gaussian closure, the response's moments can be obtained. Subsequently, a multiscale algorithm for the numerical solution of moment equations is exploited to improve computational efficiency and avoid much wall-clock time. Finally, a comparison of the results with Monte Carlo(MC) simulation gives good agreement.Furthermore, the advantage of the multiscale algorithm in terms of efficiency is also demonstrated by an engineering example. 展开更多
关键词 Direct probabilistic approach nonlinear dynamic system Nonstationary random process Response’s moments Multiscale algorithm
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基于CE-Louvain分解和动态递归SVDD的分布式过程监测
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作者 王晶 刘鹏阳 +2 位作者 卢山 周萌 陈晓露 《控制理论与应用》 北大核心 2025年第8期1650-1658,共9页
针对全厂过程的复杂非线性动态特征,本文提出了一种分布式的过程监测方法.它包括两个主要内容:基于copula entropy Louvain(CE-Louvain)的过程分解和基于动态递归支持向量数据描述(DR-SVDD)的故障检测.首先,根据机理知识将全厂过程中的... 针对全厂过程的复杂非线性动态特征,本文提出了一种分布式的过程监测方法.它包括两个主要内容:基于copula entropy Louvain(CE-Louvain)的过程分解和基于动态递归支持向量数据描述(DR-SVDD)的故障检测.首先,根据机理知识将全厂过程中的变量初步映射为和过程结构相对应的无向图模型,引入CE来描述无向图中不同节点(即过程变量)之间的权重,并基于将CE-Louvain算法精细分解为合理的子块.然后,针对每个子块提出了基于DR-SVDD的分布式故障检测方法以提高故障检测率.最后,利用贝叶斯融合推理方法得到全局过程监测结果.提出的方法在Tennesse-Eastman(TE)过程中得到了验证. 展开更多
关键词 非线性动态过程 过程监测 CE-Louvain分解 支持向量数据描述
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基于WPG-KNMF的非线性动态过程监控研究
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作者 张成 邓成龙 李元 《控制理论与应用》 北大核心 2025年第3期569-578,共10页
针对非线性动态过程故障检测问题,本文提出一种基于Wasserstein距离投影梯度核非负矩阵分解(WPGKN-MF)的故障检测方法.首先,采用投影梯度方法对KNMF的基矩阵和系数矩阵进行更新.其次,在高维特征空间中,使用Wasserstein距离结合滑动窗口... 针对非线性动态过程故障检测问题,本文提出一种基于Wasserstein距离投影梯度核非负矩阵分解(WPGKN-MF)的故障检测方法.首先,采用投影梯度方法对KNMF的基矩阵和系数矩阵进行更新.其次,在高维特征空间中,使用Wasserstein距离结合滑动窗口方法,构造新的统计量进行故障检测.本文方法将KNMF中迭代方法改进为投影梯度方法,通过KNMF将数据的非线性结构捕获,并结合Wasserstein距离消除样本间自相关性影响.通过一个数值例子和基于工业控制系统执行器诊断方法的开发与应用(DAMADICS)过程的实验数据进行仿真实验,与传统核主成分分析(KPCA)、核非负矩阵分解等方法进行对比,仿真结果验证了本文所提方法的有效性. 展开更多
关键词 核非负矩阵分解 非线性过程 动态过程 投影梯度 Wasserstein距离 故障检测
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基于BU-DDTW多阶段SPCA-PSD间歇过程故障监测
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作者 王震 高丙朋 +2 位作者 蔡鑫 祝景亮 郭思旭 《广西师范大学学报(自然科学版)》 北大核心 2025年第5期91-103,共13页
针对间歇过程中复杂的动态特性和多阶段特性导致故障监测精度低的问题,本文提出一种基于自底向上导数动态时间规整(BU-DDTW)的半正定稀疏主成分分析(SPCA-PSD)多阶段间歇过程故障监测方法。首先,利用encoder-decoder模型捕捉批处理后的... 针对间歇过程中复杂的动态特性和多阶段特性导致故障监测精度低的问题,本文提出一种基于自底向上导数动态时间规整(BU-DDTW)的半正定稀疏主成分分析(SPCA-PSD)多阶段间歇过程故障监测方法。首先,利用encoder-decoder模型捕捉批处理后的时间序列动态特征。其次,结合BU-DDTW合并策略,衡量不同子序列之间的动态结构相似度,实现精准阶段划分。然后,通过SPCA-PSD方法引入稀疏性和半正定约束,精准识别表征各阶段特性的关键变量,构建多阶段故障监测模型。在青霉素补料分批发酵过程数据进行实验验证中,本文对6种不同故障类型的平均故障监测率达95.2%,显著优于其他方法,结果证明本文所提方法在间歇过程阶段划分的有效性,同时增强了多阶段故障监测模型的准确性和可解释性。 展开更多
关键词 间歇过程 故障监测 阶段划分 非线性 动态性
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Toward exploring noncontinuous-state dynamics based on pulse-modulated frequency-shifted laser feedback interferometry
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作者 JIE LI YUNKUN ZHAO +5 位作者 JIE LIU JIANCHU LIU HONGTAO LI QI YU JIALIANG LV LIANG LU 《Photonics Research》 2025年第3期671-686,共16页
An exhaustive study of the noncontinuous-state laser dynamics associated with the transient optical process is significant because it reveals the complex physical mechanisms and characteristics in nonlinear laser syst... An exhaustive study of the noncontinuous-state laser dynamics associated with the transient optical process is significant because it reveals the complex physical mechanisms and characteristics in nonlinear laser systems.In this study,in-depth theoretical interpretation and experimental verification of the noncontinuous-state dynamics in laser system are presented,based on developed pulse-modulated frequency-shifted laser feedback interferometry(LFI).By introducing external pulse modulation,we investigate the nonlinear time-of-flight dynamics and related photon behaviors evolution of the pulsed LFI system by observing the changes in effective interference time sequences for interference realization and attainable minimum feedback photon number of the signal under various modulated noncontinuous states.Implementation of the pulse-modulated LFI scheme should exceed the pulse overlapping time window limit of 1.93μs to effectively extract and preserve the extracavity feedback photon information.Experiments reveal that the minimum feedback photon number of signals successfully measured by the pulsed LFI sensor is 0.067 feedback photons per Doppler cycle,exhibiting high sensitivity for extremely weak signal detection.Further,simultaneous measurement for velocity and distance of the moving object is performed to validate the feasibility and applicability of the pulsed LFI.The system can successfully achieve large-range simultaneous measurements within the velocity range of 73.5-612.6 mm∕s,over a distance of 25.5 km.This work opens the way to unexplored frontiers of pulsed LFI to fill the research gap in noncontinuous laser dynamics in this field,showcasing diverse and wide-ranging applications in the realm of integrated sensing,remote monitoring,and positioning and navigation. 展开更多
关键词 nonlinear time flight dynamics laser system pulse modulated frequency shifted laser feedback interferometry transient optical process sensitivity nonlinear laser systemsin noncontinuous state dynamics photon behavior evolution
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Real-Time Proportional-Integral-Derivative(PID)Tuning Based on Back Propagation(BP)Neural Network for Intelligent Vehicle Motion Control
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作者 Liang Zhou Qiyao Hu +1 位作者 Xianlin Peng Qianlong Liu 《Computers, Materials & Continua》 2025年第5期2375-2401,共27页
Over 1.3 million people die annually in traffic accidents,and this tragic fact highlights the urgent need to enhance the intelligence of traffic safety and control systems.In modern industrial and technological applic... Over 1.3 million people die annually in traffic accidents,and this tragic fact highlights the urgent need to enhance the intelligence of traffic safety and control systems.In modern industrial and technological applications and collaborative edge intelligence,control systems are crucial for ensuring efficiency and safety.However,deficiencies in these systems can lead to significant operational risks.This paper uses edge intelligence to address the challenges of achieving target speeds and improving efficiency in vehicle control,particularly the limitations of traditional Proportional-Integral-Derivative(PID)controllers inmanaging nonlinear and time-varying dynamics,such as varying road conditions and vehicle behavior,which often result in substantial discrepancies between desired and actual speeds,as well as inefficiencies due to manual parameter adjustments.The paper uses edge intelligence to propose a novel PID control algorithm that integrates Backpropagation(BP)neural networks to enhance robustness and adaptability.The BP neural network is first trained to capture the nonlinear dynamic characteristics of the vehicle.Thetrained network is then combined with the PID controller to forma hybrid control strategy.The output layer of the neural network directly adjusts the PIDparameters(k_(p),k_(i),k_(d)),optimizing performance for specific driving scenarios through self-learning and weight adjustments.Simulation experiments demonstrate that our BP neural network-based PID design significantly outperforms traditional methods,with the response time for acceleration from 0 to 1 m/s improved from 0.25 s to just 0.065 s.Furthermore,real-world tests on an intelligent vehicle show its ability to make timely adjustments in response to complex road conditions,ensuring consistent speed maintenance and enhancing overall system performance. 展开更多
关键词 PID control backpropagation neural network hybrid control nonlinear dynamic processes edge intelligence
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基于OpenSees的RC框架结构连续倒塌全过程高效分析方法
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作者 王贞 余启航 +2 位作者 李鑫蔚 程潇俊 吴斌 《振动与冲击》 北大核心 2025年第20期132-140,共9页
为解决钢筋混凝土(reinforced concrete,RC)框架结构抗倒塌能力快速评估中的计算耗时长与计算收敛性问题,提出了一种基于OpenSees的RC框架结构倒塌全过程高效分析方法。该方法采用离散质量模型与显式逐步积分方法,避免了隐式分析方法中... 为解决钢筋混凝土(reinforced concrete,RC)框架结构抗倒塌能力快速评估中的计算耗时长与计算收敛性问题,提出了一种基于OpenSees的RC框架结构倒塌全过程高效分析方法。该方法采用离散质量模型与显式逐步积分方法,避免了隐式分析方法中迭代收敛性问题以及精细化有限元分析中建模过程繁琐、求解极端耗时等困难,实现了RC结构连续倒塌全过程的快速模拟。对比LS-DYNA精细化模型,设置RC框架结构底层边柱、次中柱及中柱三类拆柱工况,验证了方法的有效性和准确性。结果显示,该方法在倒塌形态、关键节点位移和塌落评价指标等方面,与LS-DYNA精细化模型计算结果基本一致。同时,该方法能够全面揭示RC框架结构倒塌过程中内力重分布、梁柱节点触地、链式反应,有效模拟结构完全倒塌至地面的全过程。研究表明,该方法不仅具备较高的计算效率,且适用于各种拆柱工况下的倒塌行为快速评估,为结构抗倒塌性能研究提供了有效工具。 展开更多
关键词 连续倒塌全过程 RC框架结构 非线性动力分析 拆除构件法 OPENSEES
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Hydrodynamic Limit for Exclusion Processes
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作者 Tadahisa Funaki 《Communications in Mathematics and Statistics》 SCIE 2018年第4期417-480,共64页
The exclusion process,sometimes called Kawasaki dynamics or lattice gas model,describes a system of particles moving on a discrete square lattice with an interaction governed by the exclusion rule under which at most ... The exclusion process,sometimes called Kawasaki dynamics or lattice gas model,describes a system of particles moving on a discrete square lattice with an interaction governed by the exclusion rule under which at most one particle can occupy each site.We mostly discuss the symmetric and reversible case.The weakly asymmetric case recently attracts attention related to KPZ equation;cf.Bertini and Giacomin(Commun Math Phys 183:571–607,1995)for a simple exclusion case and Gonçalves and Jara(Arch Ration Mech Anal 212:597–644,2014)for an exclusion process with speed change,see also Gonçalves et al.(Ann Probab 43:286–338,2015),Gubinelli and Perkowski(J Am Math Soc 31:427–471,2018).In Sect.1,as a warm-up,we consider a simple exclusion process and discuss its hydrodynamic limit and the corresponding fluctuation limit in a proper space–time scaling.From this model,one can derive a linear heat equation and a stochastic partial differential equation(SPDE)in the limit,respectively.Section 2 is devoted to the entropy method originally invented by Guo et al.(Commun Math Phys 118:31–59,1988).We consider the exclusion process with speed change,in which the jump rate of a particle depends on the configuration nearby the particle.This gives a non-trivial interaction among particles.We study only the case that the jump rate satisfies the so-called gradient condition.The hydrodynamic limit,which leads to a nonlinear diffusion equation,follows from the local ergodicity or the local equilibrium of the system,and this is shown by establishing one-block and twoblock estimates.We also discuss the fluctuation limit which follows by showing the so-called Boltzmann–Gibbs principle.Section 3 explains the relative entropy method originally due to Yau(Lett Math Phys 22:63–80,1991).This is a variant of GPV method and gives another proof for the hydrodynamic limit.The difference between these two methods is as follows.Let N^(d)be the volume of the domain on which the system is defined(typically,d-dimensional discrete box with side length N)and denote the(relative)entropy by H.Then,H relative to a global equilibrium behaves as H=O(N^(d))(or entropy per volume is O(1))as N→∞.GPV method rather relies on the fact that the entropy production I,which is the time derivative of H,behaves as O(N^(d−2))so that I per volume is o(1),and this characterizes the limit measures.On the other hand,Yau’s method shows H=o(Nd)for H relative to local equilibria so that the entropy per volume is o(1)and this proves the hydrodynamic limit.In Sect.4,we considerKawasaki dynamics perturbed by relatively largeGlauber effect,which allows creation and annihilation of particles.This leads to the reaction–diffusion equation in the hydrodynamic limit.We discuss especially the equation with reaction term of bistable type and the problem related to the fast reaction limit or the sharp interface limit leading to the motion by mean curvature.We apply the estimate on the relative entropy due to Jara and Menezes(Non-equilibrium fluctuations of interacting particle systems,2017;Symmetric exclusion as a random environment:invariance principle,2018),which is actually obtained as a combination of GPV and Yau’s estimates.This makes possible to study the hydrodynamic limit for microscopic systems with another diverging factors apart from that caused by the space–time scaling. 展开更多
关键词 Exclusion process Kawasaki dynamics Hydrodynamic limit Scaling limit Relative entropy nonlinear diffusion equation
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基于非线性拟合的汽车动态称重数据处理新方法 被引量:15
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作者 周志峰 蔡萍 +1 位作者 陈日兴 黎志刚 《上海交通大学学报》 EI CAS CSCD 北大核心 2006年第5期709-712,共4页
针对影响汽车动态称重精度的低频动态载荷问题,提出了基于非线性拟合的数据处理新方法.根据称重信号的特点,以Levenberg-Marquardt算法为基础,进行了去除低频动态载荷的仿真试验和实际信号试验.结果表明,该方法可以有效地降低低频动态... 针对影响汽车动态称重精度的低频动态载荷问题,提出了基于非线性拟合的数据处理新方法.根据称重信号的特点,以Levenberg-Marquardt算法为基础,进行了去除低频动态载荷的仿真试验和实际信号试验.结果表明,该方法可以有效地降低低频动态载荷对称重精度的影响,车速小于14.5 km/h时的最大相对误差为3.46%. 展开更多
关键词 动态称重 非线性拟合 动态数据处理
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船舶在随机横浪中的奇异倾覆机理 被引量:10
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作者 袁远 余音 金咸定 《船舶力学》 EI 2004年第1期44-50,共7页
本文应用非线性随机动力系统理论,从系统稳定性的角度来分析船舶在随机横浪上的运动稳定性,籍此来研究随机海浪中船舶奇异倾覆的机理。本文的研究发现随机动力系统的全局分岔是导致系统失稳并导致船舶倾覆的一种途径。基于这一思路借助... 本文应用非线性随机动力系统理论,从系统稳定性的角度来分析船舶在随机横浪上的运动稳定性,籍此来研究随机海浪中船舶奇异倾覆的机理。本文的研究发现随机动力系统的全局分岔是导致系统失稳并导致船舶倾覆的一种途径。基于这一思路借助随机Melnikov方法,通过求取相流函数零点得到了船舶运动全局稳定性丧失时海浪条件的阈值,从而可以对船舶的抗倾覆能力作出定量的考察。 展开更多
关键词 船舶倾覆 随机分岔 船舶横摇 MELNIKOV方法 稳定性
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铣削过程非线性动力学的研究进展 被引量:4
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作者 吴石 渠达 +1 位作者 刘献礼 肖飞 《哈尔滨理工大学学报》 CAS 2013年第4期1-6,共6页
随着高速铣削技术的发展,铣削过程动力学的传统线性理论已经不能保证所建模型的精确度,而非线性理论可以更好地解释颤振发生、发展和自稳定的全过程.考虑铣削过程非线性因素,是准确预测高速铣削过程中的颤振临界值、工件表面位置误差的... 随着高速铣削技术的发展,铣削过程动力学的传统线性理论已经不能保证所建模型的精确度,而非线性理论可以更好地解释颤振发生、发展和自稳定的全过程.考虑铣削过程非线性因素,是准确预测高速铣削过程中的颤振临界值、工件表面位置误差的前提.从探讨高速铣削过程非线性动力学发展的角度,分析了动力学模型中非线性因素的来源,介绍了非线性铣削系统再生颤振、分叉与混沌的研究进展,并展望了铣削过程非线性动力学的发展趋势. 展开更多
关键词 铣削动力学 非线性 颤振 混沌振动
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微生物间歇发酵非线性动力系统的性质及最优控制 被引量:8
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作者 李晓红 冯恩民 修志龙 《运筹学学报》 CSCD 北大核心 2005年第4期89-96,共8页
本文针对微生物间歇发酵制取1,3-丙二醇非线性动力系统,以产物1,3-丙二醇的生产强度最大为目标泛函,建立了最优控制模型.用不可微优化理论与方法证明了模型最优解的存在性.论述了最优性函数与一阶最优性条件的等价性.
关键词 运筹学 间歇发酵 非线性动力系统 最优控制 最优性函数
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柴油机动态过程仿真研究 被引量:4
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作者 李煜晖 崔可润 鲁凯生 《武汉理工大学学报(交通科学与工程版)》 北大核心 2003年第3期288-290,共3页
以非增压柴油机为研究对象建立了零维模型 ,模拟了非增压柴油机的稳态特性和调速过程 ,实验表明 ,仿真精度达到了误差 2 %以下 .从动态过程控制器设计的角度 ,对动态模型进行了简化 ,简化后的模型保持了柴油机动力特性的非线性特征 ,其... 以非增压柴油机为研究对象建立了零维模型 ,模拟了非增压柴油机的稳态特性和调速过程 ,实验表明 ,仿真精度达到了误差 2 %以下 .从动态过程控制器设计的角度 ,对动态模型进行了简化 ,简化后的模型保持了柴油机动力特性的非线性特征 ,其调速过程仿真精度达到了 95 % . 展开更多
关键词 非线性系统 动态过程 仿真计算
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BTA深孔加工钻杆系统的稳定性及分岔 被引量:9
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作者 孔令飞 李言 吕延军 《兵工学报》 EI CAS CSCD 北大核心 2009年第12期1684-1690,共7页
研究了BTA深孔加工钻杆系统的稳定性和分岔。考虑了钻杆质量偏心和切削力波动的影响,利用切削液非线性流体力以增加数值计算的精度。通过引入变分约束原理的有限元方法,同时完成了非线性分析所需的流体力及其Jacobian矩阵的计算。在稳... 研究了BTA深孔加工钻杆系统的稳定性和分岔。考虑了钻杆质量偏心和切削力波动的影响,利用切削液非线性流体力以增加数值计算的精度。通过引入变分约束原理的有限元方法,同时完成了非线性分析所需的流体力及其Jacobian矩阵的计算。在稳定性分析中,通过改变系统的时间尺度,将非线性钻杆系统周期轨迹的周期显式地出现在钻杆系统的系统方程中;然后对传统打靶法进行改造,将周期也作为一个参数一起加入打靶法的迭代过程,确定了钻杆运行周期轨迹并有效减少了周期计算量。结合Floquet稳定性理论,将理论计算与实验结果相结合验证了上述方法的正确性和有效性。 展开更多
关键词 机械制造工艺与设备 深孔加工 钻杆 非线性动力学 稳定性 分岔
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