集装箱码头物流系统是典型的离散事件系统，基于离散事件系统规范，分析了该系统仿真模型中的实体及其功能，采用耦合模型和原子模型的描述形式，构建了集装箱码头物流系统的离散事件系统规范仿真模型。通过em-Plant仿真软件进行仿真实验，获得了较为合理的仿真结果，为集装箱码头物流系统整体性模块化研究奠定了基础。

In this paper, on the basis of the standard of the discrete event system, we analyzed the entities and functions of the simulation model of the container terminal logistics systems, then established the discrete event system standard based simulation model of the container terminal logistics systems using the coupling model and the atomic model, and at the end, applied it in a simulation experiment on the eM-Plant platform.

研究一类具有饱和发生率的SIR传染病模型，利用Mickens的非标准有限差分方法（ NSFD）得到对应的离散传染病模型，在采用非标准离散化过程中，使得微分方程解的正性和模型守恒律这两个重要性质与离散模型保持一致。

A class of SIR epidemic model with saturation incidence is studied .A corresponding discrete-time model is constructed by using the non-standard finite difference scheme ( NSFD) methodology of Mickens .And the important feature is that both the positivity and a conservation law for the system of differential equations are maintained by the discretization .

通过分析连续柔性成形装置的结构特点,提出了柔性辊离散和连续两种建模方法.从接触方式、应力分布等方面对两种有限元模型进行比较,结果表明:柔性辊离散模型中的刚体短辊以分段折线逼近目标曲线形状,与板料为点接触,柔性辊连续模型中的实体辊与板料为光滑曲线接触;相比于光滑曲线接触,从厚度分布可以看出点接触导致了鞍面件厚度分布不均匀,产生了局部变形;柔性辊连续模型的应力分布较离散模型均匀.采用两种有限元模型成形鞍面件和球面件并与实验结果比较,可知柔性辊连续模型预测实验件的偏差小于离散模型的偏差,说明其更适用于模拟连续柔性成形过程.

Flexible roll discrete and continuous modeling methods were proposed by analyzing the structure characteristics of continuous flexible roll forming setup .Two finite element models were compared from the following aspects :contact way and stress distribution .The results show that the contact way between rigid roll and sheet metal is point contact in discrete model ,which makes uneven distribution of thickness and has local deformation on saddle surface part ,but that is smooth curve contact in continuous model .Compared with discrete model , the stress distribution of continuous model are more uniform .The saddle and spherical surface parts were formed by the two finite element models ,w hich show that the deviations of predicting experimental parts by continuous model are smaller than those by discrete model ,indicating that the former is more suitable for simulating the continuous flexible roll forming process .

针对机织物卡尔丹角多体模型维数较高、计算效率较低的问题,采用离散零空间法降低多体动力学方程维数.通过隐式龙格库塔法对方程直接离散,结合离散零空间等效变换,消去拉格朗日乘子项和结点参数化实现两次系统降维,提出基于离散零空间法的机织物降维多体模型;通过KES单轴拉伸试验与仿真,验证了模型的正确性和有效性;并通过两种模型计算复杂度及计算效率的特征指标对比,证实了本文模型在降维和计算高效方面的优势,尤适于大型织物仿真.

In the light of that in the model of rigid bodies with Cardan angular coordinates for plain-weave fabrics (CMRBF) the dimensionality is high and poor of the efficiency, the discrete null space method is applied to reduce the dimensionality of the equations of motion for multibody systems. Applying the implicit Runge-Kutta method(IRK) to directly discretize the equations and combining with discrete null space equivalent transformation , the Lagrange multipliers are eliminated, and the nodal reparametrisation is carryied out, thus twice dimensionality reduction of system is realized. Hence, the dimension reduction multibody model of rigid bodies for woven fabrics based on discrete null space method (DR-CMRBF) is proposed. Through the Kawabata Evaluation System for Fabrics(KES) uniaxial tensile experimens and simulations, the correctness and validity of the proposed model are tested and verified. Furthermore, by comparing the index of computational complexity and computational efficiency

根据室内外试验观测数据和模拟结果，对比分析了基于混合数值解法求解的一维畦灌地表水流运动模型以及基于二阶时间离散精度有限差分法-四阶空间离散精度有限体积法解算的一维土壤水动力学模型的模拟效果，检验了现有迭代耦合模式改善后的模拟性能。结果表明，利用混合数值解法求解一维畦灌地表水流运动模型具有比 Roe 有限体积法更好的数值计算稳定性和收敛性；与一阶时间离散精度有限差分法-二阶空间离散精度有限差分法及一阶时间离散精度有限差分法-二阶空间离散精度有限体积法相比，采用二阶时间离散精度有限差分法-四阶空间离散精度有限体积法解算一维土壤水动力学模型具备较好的模拟精度、质量平衡性和收敛速率。与此同时，改善后的迭代耦合模式呈现出较好的模拟精度和质量守恒性，且计算效率平均提高0.7倍以上。基于数值解法和迭代耦合模式同步改进后构建的一维畦灌地表水流-土壤水动力学耦合模型，具有提高模拟精度和计算效率的良好能力。

Simulated effects of the one-dimensional soil water dynamics model, solved by the fourth-order accuracy finite volume method for spatial discretization and the second-order accurate finite difference meth?od for temporal discretization,and the one-dimensional surface flow hydrodynamic model,solved by the hy?brid numerical method,were compared based on soil columns and field irrigation experiments,and the sim?ulated performance of the improved iterative coupling method was tested. The results show that the one-di?mensional surface flow hydrodynamic model solved by the hybrid numerical method exhibits better computa?tional stability and convergence performance than that of Roe finite volume method. The proposed one-di?mensional soil water dynamics model presents better computational accuracy and convergence rate than that solved by the second-order accurate finite volume method or second-order accurate finite difference method for spatial discretization with first-order finite difference