A Gauss–Seidel type solver for the fast computation of input-constrained control systems

An important class of nonlinear control systems can be represented as the feedback interconnection of two parts: a linear time-invariant system and a block of decentralized nonlinearities. When the linear time-invariant part has a nontrivial feedthrough term or the nonlinearity has a feedback gain, control computation involves the online implementation of a multivariable algebraic loop which must be resolved at each sampling instant. The requirements for such online computation may result in several implementation issues, especially in real-time and embedded control applications. This paper considers the implementation of such algebraic loops arising from several input-constrained systems. The proposed solution algorithm is globally convergent for a very large class of feedthrough or feedback gains and shows promise for real-time and embedded control applications where a fast but approximate solution is of the essence.     

Optimum active and inert ratios for different metamorphic grade coals

In order to quantitatively describe the difference of optimum active and inert ratio of various metamorphic grade coking coals,the rule of coke micro-strength index (MSI),determinated by adding different proportions of inert content to ten kinds of single coal,changing with active and inert ratio has been investigated.Three kinds of change rule of the MSI of ten kinds of single coal changing with active and inert ratio have been obtained in the research.It has been demonstrated that Gauss curve model is the optimal model to describe the optimum active and inert ratio of different metamorphic grade coals.On this basis,the optimum active and inert ratio of different metamorphic grade coals can be given.     

回顾看涨幂期权的定价

根据风险中性定价原理,借助几何Brown运动击中双边障碍时刻的分布,给出了回顾看涨幂期权的定价公式.     

流体饱和多孔隙介质中弹性波运动方程的解—伪谱法

本文提出了一种解流体饱和多孔隙介质中波传播方程的数值方法，并详细推导了该方法的计算公式．用此公式对单界面模型中地震波的传播进行了模拟，结果与Ｂｉｏｔ理论预测的相符．     

在f=p3情形下高斯和的计算

在前导子f=p^3情形下对带有狄利克雷特征标的高斯和。利用数论中的一些定义，定理和结论。给出具体计算。得出精确的具体合同式。     

电磁场边界条件的一种新推导方法

对由不同煤质所组成的电磁场场域，当分界面上场的散度源和旋度源不为零时，场量将在分界面两侧发生突变，通常使用的单一煤质区域中的斯托克斯公式不再适用这种情况，推广了单一煤质中的斯托克斯公式，得到了适用于多媒质区域的多曲面斯托克斯公式，对于由不同煤质所组成的电磁场场域，利用所推广的多曲面斯托克斯公式，给出了电磁场边界条件的一种新的推导方法，所推导的公式对于由多种媒质组成的矢量场有广泛应用。     

Sinh—Gordon方程的微分几何解法

本文给出Ｓｉｎｈ—Ｇｏｒｄｏｎ方程的一种微分几何解法     

Application of the chebyshev-fourier pseudospectral method to the eigenvalue analysis of circular mindlin plates with free boundary conditions

An eigenvalue analysis of the circular Mindlin plates with free boundary conditions is presented. The analysis is based on the Chebyshev-Fourier pseudospectral method. Even though the eigenvalues of lower vibration modes tend to convergence more slowly than those of higher vibration modes, the eigenvalues converge for sufficiently fine pseudospectral grid resolutions. The eigenvalues of the axisymmetric modes are computed separately. Numerical results are provided for different grid resolutions and for different thickness-to-radius ratios.     

Eigenvalue analysis of rectangular mindlin plates by chebyshev pseudospectral method

A study of free vibration of rectangular Mindlin plates is presented. The analysis is based on the Chebyshev pseudospectral method, which uses test functions that satisfy the boundary conditions as basis functions. The result shows that rapid convergence and accuracy as well as the conceptual simplicity are achieved when the pseudospectral method is applied to the solution of eigenvalue problems. Numerical examples of rectangular Mindlin plates with clamped and simply supported boundary conditions are provided for various aspect ratios and thickness-to-length ratios.     

A Smoothed Finite Element Method for Mechanics Problems

In the finite element method (FEM), a necessary condition for a four-node isoparametric element is that no interior angle is greater than 180° and the positivity of Jacobian determinant should be ensured in numerical implementation. In this paper, we incorporate cell-wise strain smoothing operations into conventional finite elements and propose the smoothed finite element method (SFEM) for 2D elastic problems. It is found that a quadrilateral element divided into four smoothing cells can avoid spurious modes and gives stable results for integration over the element. Compared with original FEM, the SFEM achieves more accurate results and generally higher convergence rate in energy without increasing computational cost. More importantly, as no mapping or coordinate transformation is involved in the SFEM, its element is allowed to be of arbitrary shape. Hence the restriction on the shape bilinear isoparametric elements can be removed and problem domain can be discretized in more flexible ways, as demonstrated in the example problems.