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本文详细考察了二能级原子理论和相应的经典理论之间的相似性。当我们联系状态计算物理量值的时候,在Heisenberg表象中表现出的这一熟知的相似性将受到损害。这一损害与状态的定义有关。用一对矢量定义状态可保持这一相似性不受损害。 相似文献
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基于客户端装备系统可用度,构建一个由备件库存和服务台组成的闭环装备保障系统,通过分析备件库存水平状态特征,推导出备件库存水平状态稳态概率分布,并计算出可用度等几个保障质量指标,建立了基于可用度目标约束的保障系统控制优化模型,采用遗传算法并通过数值仿真揭示出可用度性质和保障系统的运作管理策略. 相似文献
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研究了一种多状态退化系统,该系统由于在工作过程中逐渐退化,导致系统的效率降低.为了减少系统的失效率和退化率,系统会受到随机失效后的小修和退化到最后一个可接受工作状态时的预防性维修.在这种具有小修和不完全预防性维修的多状态退化系统模型中,假定系统能连续退化成一些离散状态,并且这些离散状态是从正常工作状态一直到完全失效状态.当系统逐渐退化到某个临界值(这里把它称作不可接受状态)时,就视系统完全失效,那么在最后一个可接受状态时系统就会得到预防性维修;当系统从任意的工作状态随机失效后就会得到小修.在这个模型中,基于它是一个连续时间的马尔可夫过程,来计算稳态可用度指标. 相似文献
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基于状态转移模型计算的条件期望与方差,可以应用到金融领域,计算和度量市场在不同状态下的收益与风险.Nielson基于2状态转移模型,计算了2状态下股市的收益率的条件期望与方差.然而,实际研究中,常需要用到3状态、甚至多状态的状态转移模型.因此,基于Nielson的研究,从2状态推广到了$N$状态.基于$N$状态转移模型计算了条件期望、条件方差及无条件期望、无条件方差,该结果更具普遍性且形式更为简洁.最后,采用计算期望与方差的方法,分析中国股市收益率与波动率.实证结果表明,中国股市除存在牛市、熊市外,还存在政策市,且其具有`` 低风险,高收益"的特点.利用$N$状态转移模型计算的期望与方差可以更合理地度量金融市场在不同情况下的收益与风险. 相似文献
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基于Copula相关性理论,考虑可修系统零部件工作寿命、故障部件修复时间之间的正相关性,且将零件工作寿命、修复时间放宽到一般连续分布,而不局限于指数分布.提出微时间差t→t+△t内系统一步状态转移矩阵概念,进而演算出状态转移密度矩阵,经系统状态方程,分别给出了任意时刻t单部件、串联型、二不同单元和一修理工组成的并联可修系统的可用度和稳态可用度计算模型.通过算例,说明该理论方法的可行性. 相似文献
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本文研究了载电流夹紧杆在磁场作用下的非线性稳定性,其磁场由两根无限长相互平行的刚性直导线产生.杆的自然状态在刚性导线所在的平面内,并且与两刚性导线等距.首先,在空间变形的假定下,给出了问题的数学描述,讨论了线性化问题和临界电流.其次,证明了杆的过屈曲状态总是平面的.最后,数值计算了分支解的全局响应,得到了杆过屈曲状态的挠度、内力和弯矩的分布.结果表明,载电流杆既可发生超临界屈曲,又可发生次临屈界曲,其性态依赖于杆与导线间的距离;同时,在超临界的过屈曲状态上还存在极限点型的失稳,这与通常的压杆失稳有着本质的区别. 相似文献
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The Roppenecker [11] parameterization of multi-input eigenvalue assignment, which allows for common open- and closed-loop eigenvalues, provides a platform for the investigation of several issues of current interest in robust control. Based on this parameterization, a numerical optimization method for designing a constant gain feedback matrix which assigns the closed-loop eigenvalues to desired locations such that these eigenvalues have low sensitivity to variations in the open-loop state space model was presented in Owens and O'Reilly [8]. In the present paper, two closely related numerical optimization methods are presented. The methods utilize standard (NAG library) unconstrained optimization routines. The first is for designing a minimum gain state feedback matrix which assigns the closed-loop eigenvalues to desired locations, where the measure of gain taken is the Frobenius norm. The second is for designing a state feedback matrix which results in the closed-loop system state matrix having minimum condition number. These algorithms have been shown to give results which are comparable to other available algorithms of far greater conceptual complexity. 相似文献
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Fourier expansion based recursive algorithms for periodic Riccati and Lyapunov matrix differential equations 总被引:1,自引:0,他引:1
Hai-Jun Peng Zhi-Gang Wu Wan-Xie Zhong 《Journal of Computational and Applied Mathematics》2011,235(12):3571-3588
Combining Fourier series expansion with recursive matrix formulas, new reliable algorithms to compute the periodic, non-negative, definite stabilizing solutions of the periodic Riccati and Lyapunov matrix differential equations are proposed in this paper. First, periodic coefficients are expanded in terms of Fourier series to solve the time-varying periodic Riccati differential equation, and the state transition matrix of the associated Hamiltonian system is evaluated precisely with sine and cosine series. By introducing the Riccati transformation method, recursive matrix formulas are derived to solve the periodic Riccati differential equation, which is composed of four blocks of the state transition matrix. Second, two numerical sub-methods for solving Lyapunov differential equations with time-varying periodic coefficients are proposed, both based on Fourier series expansion and the recursive matrix formulas. The former algorithm is a dimension expanding method, and the latter one uses the solutions of the homogeneous periodic Riccati differential equations. Finally, the efficiency and reliability of the proposed algorithms are demonstrated by four numerical examples. 相似文献
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In orbit determination, the precision ephemeris and state transition matrix are usually obtained by solving two groups of
ordinary differential equations with numerical integration method due to the complexity of the force models. A kind of simplified
analytical method to compute the state transition matrix is given. The method is not only very efficient for the case where
the orbit arc is not too long, but also can avoid the integration of two groups of ordinary differential equations at the
same time. Some practical test examples also show the efficiency of the method. 相似文献
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Yuping Zhang Xinzhi Liu Hong Zhu Shouming Zhong 《Applied mathematics and computation》2007,190(2):1258-1266
In this paper, the problems of asymptotical stability and stabilization of a class of switched neutral control systems are investigated. A delay-dependent stability criterion is formulated in term of linear matrix inequalities (LMIs) by using quadratic Lyapunov functions and inequality analysis technique. The corresponding switching rule is obtained through dividing the state space properly. Also, the synthesis of stabilizing state-feedback controllers are done such that the close-loop system is asymptotically stable. Two numerical examples are given to show the proposed method. 相似文献
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本文研究了具有非线性扰动的不确定随机时变时滞系统的鲁棒镇定的问题.构造了适当的Lyapunov-Krasovskii泛函并利用自由权矩阵方法,借助于线性矩阵不等式(LMI)技术,设计了一个无记忆状态反馈控制器,并获得了不确定随机时变时滞系统的时滞依赖鲁棒镇定判据.数值例子及其仿真曲线表明所提出的理论结果是有效的. 相似文献
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In this paper we present a finite volume method for solving Hamilton-Jacobi-Bellman(HJB) equations governing a class of optimal feedback control problems. This method is based on a finite volume discretization in state space coupled with an upwind finite difference technique, and on an implicit backward Euler finite differencing in time, which is absolutely stable. It is shown that the system matrix of the resulting discrete equation is an M-matrix. To show the effectiveness of this approach, numerical experiments on test problems with up to three states and two control variables were performed. The numerical results show that the method yields accurate approximate solutions to both the control and the state variables. 相似文献
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《Communications in Nonlinear Science & Numerical Simulation》2011,16(4):2109-2129
This paper investigates delay-dependent robust exponential state estimation of Markovian jumping fuzzy neural networks with mixed random time-varying delay. In this paper, the Takagi–Sugeno (T–S) fuzzy model representation is extended to the robust exponential state estimation of Markovian jumping Hopfield neural networks with mixed random time-varying delays. Moreover probabilistic delay satisfies a certain probability-distribution. By introducing a stochastic variable with a Bernoulli distribution, the neural networks with random time delays is transformed into one with deterministic delays and stochastic parameters. The main purpose is to estimate the neuron states, through available output measurements such that for all admissible time delays, the dynamics of the estimation error is globally exponentially stable in the mean square. Based on the Lyapunov–Krasovskii functional and stochastic analysis approach, several delay-dependent robust state estimators for such T–S fuzzy Markovian jumping Hopfield neural networks can be achieved by solving a linear matrix inequality (LMI), which can be easily facilitated by using some standard numerical packages. The unknown gain matrix is determined by solving a delay-dependent LMI. Finally some numerical examples are provided to demonstrate the effectiveness of the proposed method. 相似文献
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P. T. Nam P. N. Pathirana H. Trinh 《Journal of Optimization Theory and Applications》2013,157(3):843-852
In this paper, the problem of control design for exponential convergence of state/input delay systems with bounded disturbances is considered. Based on the Lyapunov–Krasovskii method combining with the delay-decomposition technique, a new sufficient condition is proposed for the existence of a state feedback controller, which guarantees that all solutions of the closed-loop system converge exponentially (with a pre-specified convergence rate) within a ball whose radius is minimized. The obtained condition is given in terms of matrix inequalities with one parameter needing to be tuned, which can be solved by using a one-dimensional search method with Matlab’s LMI Toolbox to minimize the radius of the ball. Two numerical examples are given to illustrate the superiority of the proposed method. 相似文献
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《Communications in Nonlinear Science & Numerical Simulation》2011,16(1):10-20
In this paper, we propose and study an array of coupled delayed Lurie systems with hybrid coupling, which is composed of constant coupling, state delay coupling, and distributed delay coupling. Together with Lyapunov–Krasovskii functional method and Kronecker product properties, two novel synchronization criteria are presented within linear matrix inequalities based on generalized convex combination, in which these conditions are heavily dependent on the upper and lower bounds of state delay and distributed one. Through adjusting inner coupling matrix parameters in the derived results, we can realize the designing and applications of the addressed systems by referring to Matlab LMI Toolbox. The efficiency and applicability of the proposed criteria can be demonstrated by three numerical examples with simulations. 相似文献
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《Mathematical Methods in the Applied Sciences》2018,41(14):5466-5480
In this paper, we present a direct B‐spline spectral collocation method to approximate the solutions of fractional optimal control problems with inequality constraints. We use the location of the maximum of B‐spline functions as collocation points, which leads to sparse and nonsingular matrix B whose entries are the values of B‐spline functions at the collocation points. In this method, both the control and Caputo fractional derivative of the state are approximated by B‐spline functions. The fractional integral of these functions is computed by the Cox‐de Boor recursion formula. The convergence of the method is investigated. Several numerical examples are considered to indicate the efficiency of the method. 相似文献