期刊文献+
共找到299篇文章
< 1 2 15 >
每页显示 20 50 100
水力旋流器固体颗粒运动行为的分析 被引量:16
1
作者 王志斌 陈文梅 +1 位作者 褚良银 王升贵 《流体机械》 CSCD 北大核心 2005年第11期57-60,56,共5页
通过对旋流器内固体颗粒的受力分析,提出固体颗粒精确运动轨迹结构是由确定性的径向力、轴向力以及不确定性的随机力所决定,并对固体颗粒存在的随机因素进行了分析。在此基础上,分析了固体颗粒与液体的跟随性,认为在强湍流情况下,颗粒... 通过对旋流器内固体颗粒的受力分析,提出固体颗粒精确运动轨迹结构是由确定性的径向力、轴向力以及不确定性的随机力所决定,并对固体颗粒存在的随机因素进行了分析。在此基础上,分析了固体颗粒与液体的跟随性,认为在强湍流情况下,颗粒除在径向方向的运动有别于液体介质外,在轴向与切向也存在差异,且这种差异与颗粒粒度大小、密度、流体性质以及湍流强度有关。 展开更多
关键词 旋流器 固体颗粒 随机运动 固液跟随性
下载PDF
Comparison principle and stability criteria for stochastic differential delay equations with Markovian switching 被引量:12
2
作者 罗交晚 邹捷中 侯振挺 《Science China Mathematics》 SCIE 2003年第1期129-138,共10页
In the present paper we first obtain the comparison principle for the nonlinear stochastic differentialdelay equations with Markovian switching. Later, using this comparison principle, we obtain some stabilitycriteria... In the present paper we first obtain the comparison principle for the nonlinear stochastic differentialdelay equations with Markovian switching. Later, using this comparison principle, we obtain some stabilitycriteria, including stability in probability, asymptotic stability in probability, stability in the pth mean, asymptoticstability in the pth mean and the pth moment exponential stability of such equations. Finally, an example isgiven to illustrate the effectiveness of our results. 展开更多
关键词 comparison principle Brownian motion stochastic differential delay equations generalized Ito’s formula Markov chain
原文传递
地震动空间变异性对千米级斜拉桥结构随机地震反应的影响 被引量:13
3
作者 武芳文 赵雷 《地震工程与工程振动》 CSCD 北大核心 2009年第5期118-127,共10页
基于随机振动理论,以苏通长江公路大桥为背景,对超大跨度斜拉桥在随机地震荷载作用下的动力响应展开研究,详细分析地震动空间变化特性对千米级斜拉桥结构动力响应的影响。研究结果表明:相干效应对主梁纵向弯矩影响比较大,尤其是中跨部位... 基于随机振动理论,以苏通长江公路大桥为背景,对超大跨度斜拉桥在随机地震荷载作用下的动力响应展开研究,详细分析地震动空间变化特性对千米级斜拉桥结构动力响应的影响。研究结果表明:相干效应对主梁纵向弯矩影响比较大,尤其是中跨部位;而局部场地效应相对影响较小。对于主梁轴力而言,行波效应影响较为显著,主梁轴力的最大值增大约70%之多,但对竖向剪力并无突出影响。与一致激励比较,行波效应使得跨中竖向位移均方根增大约74%,相干效应为60%,而局部场地效应为13%。对于不同的内力和位移响应,地震动空间变化特性的影响程度和规律不尽相同,必须区别对待,具体问题具体分析。 展开更多
关键词 桥梁工程 随机振动 斜拉桥 地震动 行波效应 部分相干效应 局部场地效应
下载PDF
超大跨度斜拉桥考虑行波效应的地震动随机响应研究 被引量:12
4
作者 武芳文 薛成凤 赵雷 《地震学报》 CSCD 北大核心 2010年第2期193-202,共10页
斜拉桥地震反应不同于其它桥型,具有明显的空间耦合效应.利用有限元理论对苏通长江公路大桥的空间抗震性能进行分析,重点研究行波效应对结构响应的影响,并与一致激励计算的结果进行比较,为大跨度斜拉桥抗震分析采用随机方法提供了一定... 斜拉桥地震反应不同于其它桥型,具有明显的空间耦合效应.利用有限元理论对苏通长江公路大桥的空间抗震性能进行分析,重点研究行波效应对结构响应的影响,并与一致激励计算的结果进行比较,为大跨度斜拉桥抗震分析采用随机方法提供了一定的参考依据.研究结果表明,行波效应对斜拉桥结构内力有显著的影响,大跨度斜拉桥抗震性能分析必须考虑行波效应.而行波效应的影响与结构自身动力特性、视波速、构件位置及研究响应类型(位移与内力)相关. 展开更多
关键词 桥梁工程 随机振动 斜拉桥 地震动 行波效应
下载PDF
非线性随机地震响应的概率密度演化分析 被引量:11
5
作者 陈建兵 李杰 《武汉理工大学学报》 CAS CSCD 北大核心 2010年第9期6-10,共5页
强烈地震作用下的结构非线性随机动力响应分析对准确把握结构的安全性和所需的其他性态指标是至关重要的,但在经典随机振动和随机结构分析的理论框架下至今存在难以逾越的巨大困难。结合概率密度演化理论和基于频率优选的随机地震动谱... 强烈地震作用下的结构非线性随机动力响应分析对准确把握结构的安全性和所需的其他性态指标是至关重要的,但在经典随机振动和随机结构分析的理论框架下至今存在难以逾越的巨大困难。结合概率密度演化理论和基于频率优选的随机地震动谱表达模型,成功地实现了随机地震动激励下多自由度结构非线性随机地震响应分析。文中给出了基本理论和数值方法,并以9层框架结构为实例讨论了分析结果。指出了需要进一步研究的问题。 展开更多
关键词 非线性 随机响应 地震动 谱表达 概率密度演化
原文传递
考虑借贷过程的比例再保险最优控制模型 被引量:6
6
作者 杨瑞成 刘坤会 《北方交通大学学报》 CSCD 北大核心 2003年第6期59-62,共4页
在一类带分红过程比例再保险模型的基础上,把借贷过程这一因素考虑进去,构造了一新的包括分红过程和借贷过程的比例再保险模型.利用随机分析中的最优控制理论,通过数学分析,针对不同的参数得出了不同情形下最优控制策略及相应的最大回... 在一类带分红过程比例再保险模型的基础上,把借贷过程这一因素考虑进去,构造了一新的包括分红过程和借贷过程的比例再保险模型.利用随机分析中的最优控制理论,通过数学分析,针对不同的参数得出了不同情形下最优控制策略及相应的最大回报函数. 展开更多
关键词 随机控制 借贷过程 布朗运动 期望 最优控制策略 回报函数
下载PDF
Optimal Proportional Reinsurance for Controlled Risk Process which is Perturbed by Diffusion 被引量:6
7
作者 Zhi-bin Liang 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2007年第3期477-488,共12页
In this paper, we study optimal proportional reinsurance policy of an insurer with a risk process which is perturbed by a diffusion. We derive closed-form expressions for the policy and the value function, which are o... In this paper, we study optimal proportional reinsurance policy of an insurer with a risk process which is perturbed by a diffusion. We derive closed-form expressions for the policy and the value function, which are optimal in the sense of maximizing the expected utility in the jump-diffusion framework. We also obtain explicit expressions for the policy and the value function, which are optimal in the sense of maximizing the expected utility or maximizing the survival probability in the diffusion approximation case. Some numerical examples are presented, which show the impact of model parameters on the policy. We also compare the results under the different criteria and different cases. 展开更多
关键词 stochastic control Hamilton-Jacobi-Bellman equation JUMP-DIFFUSION brownian motion diffusion approximation proportional reinsurance
原文传递
Computational Path Planner for Product Assembly in Complex Environments 被引量:6
8
作者 SHANG Wei LIU Jianhua +1 位作者 NING Ruxin LIU Mi 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第2期282-292,共11页
Assembly path planning is a crucial problem in assembly related design and manufacturing processes. Sampling based motion planning algorithms are used for computational assembly path planning. However, the performance... Assembly path planning is a crucial problem in assembly related design and manufacturing processes. Sampling based motion planning algorithms are used for computational assembly path planning. However, the performance of such algorithms may degrade much in environments with complex product structure, narrow passages or other challenging scenarios. A computational path planner for automatic assembly path planning in complex 3D environments is presented. The global planning process is divided into three phases based on the environment and specific algorithms are proposed and utilized in each phase to solve the challenging issues. A novel ray test based stochastic collision detection method is proposed to evaluate the intersection between two polyhedral objects. This method avoids fake collisions in conventional methods and degrades the geometric constraint when a part has to be removed with surface contact with other parts. A refined history based rapidly-exploring random tree (RRT) algorithm which bias the growth of the tree based on its planning history is proposed and employed in the planning phase where the path is simple but the space is highly constrained. A novel adaptive RRT algorithm is developed for the path planning problem with challenging scenarios and uncertain environment. With extending values assigned on each tree node and extending schemes applied, the tree can adapts its growth to explore complex environments more efficiently. Experiments on the key algorithms are carried out and comparisons are made between the conventional path planning algorithms and the presented ones. The comparing results show that based on the proposed algorithms, the path planner can compute assembly path in challenging complex environments more efficiently and with higher success. This research provides the references to the study of computational assembly path planning under complex environments. 展开更多
关键词 assembly path planning motion planning stochastic collision detection rapidly-exploring random tree adaptive RRT
下载PDF
考虑地震动局部场地效应的大跨度斜拉桥随机地震响应分析 被引量:7
9
作者 武芳文 赵雷 《地震研究》 CSCD 北大核心 2010年第1期93-98,共6页
基于随机振动理论,以苏通长江公路大桥为例,研究了局部场地效应对大跨度斜拉桥地震反应的影响。结果表明:与一致激励相比,局部场地效应对结构的内力和位移影响显著;场地效应对主梁、索塔内力和位移的影响程度及规律也不尽相同,须区别对... 基于随机振动理论,以苏通长江公路大桥为例,研究了局部场地效应对大跨度斜拉桥地震反应的影响。结果表明:与一致激励相比,局部场地效应对结构的内力和位移影响显著;场地效应对主梁、索塔内力和位移的影响程度及规律也不尽相同,须区别对待分析。 展开更多
关键词 桥梁工程 随机振动 斜拉桥 地震动 局部场地效应
下载PDF
随机方法模拟地震动的应用研究 被引量:5
10
作者 董娣 刘锐 桑向国 《西北地震学报》 CSCD 北大核心 2006年第4期298-302,共5页
对随机方法模拟地震动的实际应用进行了研究。通过实际模拟验证,此方法简单有效,可为结构抗震设计提供验算依据,同时为设计反应谱的拟合提供参照数据,有一定的实用性,但仍存在一定的不足。
关键词 随机方法 模拟 地震动
下载PDF
地震动空间相干效应对大跨度斜拉桥随机地震反应的影响 被引量:5
11
作者 武芳文 薛成凤 赵雷 《世界地震工程》 CSCD 北大核心 2010年第2期107-113,共7页
随着斜拉桥跨度的增大,地震动空间效应对结构地震反应的影响成为新的研究课题。基于随机振动理论,以苏通长江公路大桥为背景,分析地震动空间相干效应对大跨度斜拉桥地震响应的影响规律。研究表明:考虑地震动相干效应后,结构的内力和位... 随着斜拉桥跨度的增大,地震动空间效应对结构地震反应的影响成为新的研究课题。基于随机振动理论,以苏通长江公路大桥为背景,分析地震动空间相干效应对大跨度斜拉桥地震响应的影响规律。研究表明:考虑地震动相干效应后,结构的内力和位移响应明显增大,且相干效应对主梁和索塔内力与位移的影响程度及规律也不尽相同,须区别对待分析。由此得出结论,对大跨度斜拉桥进行随机地震响应分析时,必须考虑地震动的空间相干效应。 展开更多
关键词 桥梁工程 随机振动 斜拉桥 地震动 相干效应
下载PDF
空间桁架在轨装配机器人的运动规划方法 被引量:1
12
作者 刘聪 李海锋 +1 位作者 王明明 罗建军 《系统工程与电子技术》 EI CSCD 北大核心 2024年第2期715-721,共7页
提出一种利用机器人完成空间桁架在轨装配的设计方案,并针对其中机器人的无碰运动规划问题,提出一种引入启发信息的运动规划方法。首先,设计了装配机器人和空间桁架系统;随后,引入基于距离场的碰撞检测算法进行空间中的障碍检测,并利用... 提出一种利用机器人完成空间桁架在轨装配的设计方案,并针对其中机器人的无碰运动规划问题,提出一种引入启发信息的运动规划方法。首先,设计了装配机器人和空间桁架系统;随后,引入基于距离场的碰撞检测算法进行空间中的障碍检测,并利用随机轨迹优化框架下的运动规划(stochastic trajectory optimization for motion planning,STOMP)算法进行机器人无碰运动规划;针对其中随机叠加轨迹方向不确定导致的规划效率低的问题提出了启发式STOMP(heuristically STOMP,hSTOMP)运动规划算法。仿真结果表明该算法能够快速得到机器人的无碰平滑关节轨迹,其中启发信息的引入大大提高了原算法的规划效率,具有一定的理论意义和应用价值。 展开更多
关键词 在轨装配 机器人 随机优化 运动规划
下载PDF
大倾角煤层开采飞矸随机运动研究 被引量:5
13
作者 王淳 刘明 +4 位作者 刘晓培 范馨月 高雯雯 王楠 戴戬 《能源与节能》 2022年第6期29-31,共3页
基于飞矸法向碰撞恢复系数的数字特征,推导出飞矸切向碰撞恢复系数的数字特征。分析参数的随机性对飞矸运动特征量的影响,得到飞矸弹跳高度和动能的均值曲线。结果表明,飞矸运动参数的随机性对飞矸运动特征量具有一定程度的影响,且随着... 基于飞矸法向碰撞恢复系数的数字特征,推导出飞矸切向碰撞恢复系数的数字特征。分析参数的随机性对飞矸运动特征量的影响,得到飞矸弹跳高度和动能的均值曲线。结果表明,飞矸运动参数的随机性对飞矸运动特征量具有一定程度的影响,且随着碰撞次数的增加,参数的随机性对飞矸弹跳高度和动能均值的影响逐渐增大。 展开更多
关键词 飞矸 随机参数 大倾角煤层 随机运动
下载PDF
WONG-ZAKAI APPROXIMATIONS FOR STOCHASTIC VOLTERRA EQUATIONS
14
作者 Jie Xu Mingbo Zhang 《Journal of Computational Mathematics》 SCIE CSCD 2024年第6期1526-1553,共28页
In this paper,we shall prove a Wong-Zakai approximation for stochastic Volterra equations under appropriate assumptions.We may apply it to a class of stochastic differential equations with the kernel of fractional Bro... In this paper,we shall prove a Wong-Zakai approximation for stochastic Volterra equations under appropriate assumptions.We may apply it to a class of stochastic differential equations with the kernel of fractional Brownian motion with Hurst parameter H∈(1/2,1)and subfractional Brownian motion with Hurst parameter H∈(1/2,1).As far as we know,this is the first result on stochastic Volterra equations in this topic. 展开更多
关键词 stochastic Volterra equations Wong-Zakai approximations Fractional Brownian motion Subfractional Brownian motion Quadratic mean convergence
原文传递
DISCRETIZATION OF JUMP STOCHASTIC DIFFERENTIAL EQUATIONS IN TERMS OF MULTIPLE STOCHASTIC INTEGRALS 被引量:1
15
作者 Li, CW Wu, SC Liu, XQ 《Journal of Computational Mathematics》 SCIE EI CSCD 1998年第4期375-384,共10页
In the Stratonovich-Taylor and Stratonovich-Taylor-Hall discretization schemes for stochastic differential equations (SDEs), there appear two types of multiple stochastic integrals respectively. The present work is to... In the Stratonovich-Taylor and Stratonovich-Taylor-Hall discretization schemes for stochastic differential equations (SDEs), there appear two types of multiple stochastic integrals respectively. The present work is to approximate these multiple stochastic integrals by converting them into systems of simple SDEs and solving the systems by lower order numerical schemes. The reliability of this approach is clarified in theory and demonstrated in numerical examples. In consequence, the results are applied to the strong discretization of both continuous and jump SDEs. 展开更多
关键词 Brownian motion Poisson process stochastic differential equation multiple stochastic integral strong discretization
原文传递
A Study on Stochastic Differential Equation Using Fractional Power of Operator in the Semigroup Theory
16
作者 Emmmanuel Hagenimana Charline Uwiliniyimana Clarisse Umuraza 《Journal of Applied Mathematics and Physics》 2023年第6期1634-1655,共22页
Stochastic differential equation (SDE) is an ordinary differential equation with a stochastic process that can model the unpredictable real-life behavior of any continuous systems. It is the combination of differentia... Stochastic differential equation (SDE) is an ordinary differential equation with a stochastic process that can model the unpredictable real-life behavior of any continuous systems. It is the combination of differential equations, probability theory, and stochastic processes. Stochastic differential equations arise in modeling a variety of random dynamic phenomena in physical, biological and social process. The SDE theory is traditionally used in physical science and financial mathematics. Recently, more researchers have been conducted in the application of SDE theory to various areas of engineering. This dissertation is mainly concerned with the existence of mild solutions for impulsive neutral stochastic differential equations with nonlocal conditions in Hilbert spaces. The results are obtained by using fractional powers of operator in the semigroup theory and Sadovskii fixed point theorem. 展开更多
关键词 stochastic Impulsive stochastic Neutral Functional Mild Solution Wiener Process Brownian motion Banach Space
下载PDF
MODIFIED SPLIT-STEP THETA METHOD FOR STOCHASTIC DIFFERENTIAL EQUATIONS DRIVEN BY FRACTIONAL BROWNIAN MOTION
17
作者 Jingjun Zhao Hao Zhou Yang Xu 《Journal of Computational Mathematics》 SCIE CSCD 2024年第5期1226-1245,共20页
For solving the stochastic differential equations driven by fractional Brownian motion,we present the modified split-step theta method by combining truncated Euler-Maruyama method with split-step theta method.For the ... For solving the stochastic differential equations driven by fractional Brownian motion,we present the modified split-step theta method by combining truncated Euler-Maruyama method with split-step theta method.For the problem under a locally Lipschitz condition and a linear growth condition,we analyze the strong convergence and the exponential stability of the proposed method.Moreover,for the stochastic delay differential equations with locally Lipschitz drift condition and globally Lipschitz diffusion condition,we give the order of convergence.Finally,numerical experiments are done to confirm the theoretical conclusions. 展开更多
关键词 stochastic differential equation Fractional Brownian motion Split-step theta method Strong convergence Exponential stability
原文传递
随机利率下带干扰的双险种Poisson-Geometric过程的破产概率 被引量:3
18
作者 马钰 夏亚峰 《甘肃科学学报》 2010年第2期148-152,共5页
建立了带随机利率和干扰项的双险种风险模型,对理赔次数服从Poisson-Geometric分布的情况,得到了破产概率的表达式.
关键词 Poisson-Geometric分布 随机利率 BROWN运动 破产概率
下载PDF
A stochastic SIS epidemic infectious diseases model with double stochastic perturbations
19
作者 Xingzhi Chen Baodan Tian +2 位作者 Xin Xu Ruoxi Yang Shouming Zhong 《International Journal of Biomathematics》 SCIE 2024年第4期235-266,共32页
In this paper,a stochastic SiS epidemic infectious diseases model with double stochastic perturbations is proposed.First,the existence and uniqueness of the positive global solution of the model are proved.Second,the ... In this paper,a stochastic SiS epidemic infectious diseases model with double stochastic perturbations is proposed.First,the existence and uniqueness of the positive global solution of the model are proved.Second,the controlling conditions for the extinction and persistence of the disease are obtained.Besides,the effects of the intensity of volatility Si and the speed of reversion 1 on the dynamical behaviors of the model are discussed.Finally,some numerical examples are given to support the theoretical results.The results show that if the basic reproduction number R_(0)^(8)<1,the disease will be extinct,that is to say that we can control the threshold R_(0)^(8)to suppress the disease outbreak. 展开更多
关键词 stochastic epidemic model Ornstein-Uhlenbeck process Brownian motion basic reproduction number EXTINCTION
原文传递
Exact solutions of stochastic fractional Korteweg de–Vries equation with conformable derivatives 被引量:2
20
作者 Hossam A.Ghany Abd-Allah Hyder M Zakarya 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期62-69,共8页
We deal with the Wick-type stochastic fractional Korteweg de–Vries(KdV) equation with conformable derivatives.With the aid of the Exp-function method, white noise theory, and Hermite transform, we produce a novel set... We deal with the Wick-type stochastic fractional Korteweg de–Vries(KdV) equation with conformable derivatives.With the aid of the Exp-function method, white noise theory, and Hermite transform, we produce a novel set of exact soliton and periodic wave solutions to the fractional KdV equation with conformable derivatives. With the help of inverse Hermite transform, we get stochastic soliton and periodic wave solutions of the Wick-type stochastic fractional KdV equation with conformable derivatives. Eventually, by an application example, we show how the stochastic solutions can be given as Brownian motion functional solutions. 展开更多
关键词 Korteweg de–Vries(KdV)equation conformable DERIVATIVE stochastic BROWNIAN motion Expfunction method
下载PDF
上一页 1 2 15 下一页 到第
使用帮助 返回顶部