高等数学在车灯线光源计算中的应用

本文应用微分几何、积分法、模拟搜索法,特征值法等许多运算方法,建立了合理的线形光源计算的数学模型.     

基于Matlab的调制解调系统仿真设计

设计了差分编码移相键控(2DPSK)调制解调系统的工作流程图,并利用Matlab软件对该系统的动态进行了模拟仿真。利用仿真的结果,从基带信号的眼图可以衡量数字信号的传输质量;由系统的输入和输出波形图可以看出,仿真实验良好。2DPSK调制解调系统的仿真设计,为以后进一步研究基于Matlab的通信实验仿真系统奠定了坚实的基础。     

主变保护误动作一例分析及探讨

2004年7月20日,110kV长城变#1主变因差动保护动作而造成主变三侧开关跳闸,经分析是由于主变保护差动回路被误短接所致,为此需采取相关的技术措施和组织措施,防止类似事故的发生.     

一阶具偏差变元的时滞微分方程非振动解的存在性

研究一类一阶非线性具偏差变元的时滞微分方程x＇（t）＋a（t）f（x（t））＋p（t）g（x（t））h（x（t-τ1（t）），x（t-τ2（t）），…，x（t-τn（t）））=0，（＊）.其中，a，p，τj∈C（R^＋，R^＋），lim（t-∈-τj（t））=＋∞，j=1，2，…，n，f，g∈C（R，R），当x≠0时，xf（x）〉0，∫1，0（1/f（x））dx=＋∞，∫0，-1（1/f（x）dx=-∞，g（x）〉0，h∈C（R^N，R），且当x1xj〉0，j=1，2，…，n时，x1h（x1，x2，…，xn）〉0.获得了方程（＊）存在正解的充分条件。     

激光场中电子被氩原子散射的微分截面研究

应用第二玻恩近似理论，在电子入射方向平行于激光场的极化方向这种特殊的散射模式下，利用光学势模型对激光场中电子一氩原子散射进行了研究。利用静电屏蔽势，分别应用低频近似和第二玻恩近似公式对激光场中电子一氩原子散射进行了计算。和实验相比较，第二玻恩近似方法给出了较好的结果；应用这个较好的理论，利用光学势模型进行了计算，得到了更好的结论。     

Lucas/Kanade Meets Horn/Schunck: Combining Local and Global Optic Flow Methods

Differential methods belong to the most widely used techniques for optic flow computation in image sequences. They can be classified into local methods such as the Lucas–Kanade technique or Bigün's structure tensor method, and into global methods such as the Horn/Schunck approach and its extensions. Often local methods are more robust under noise, while global techniques yield dense flow fields. The goal of this paper is to contribute to a better understanding and the design of novel differential methods in four ways; (i) We juxtapose the role of smoothing/regularisation processes that are required in local and global differential methods for optic flow computation. (ii) This discussion motivates us to describe and evaluate a novel method that combines important advantages of local and global approaches: It yields dense flow fields that are robust against noise. (iii) Spatiotemporal and nonlinear extensions as well as multiresolution frameworks are presented for this hybrid method. (iv) We propose a simple confidence measure for optic flow methods that minimise energy functionals. It allows to sparsify a dense flow field gradually, depending on the reliability required for the resulting flow. Comparisons with experiments from the literature demonstrate the favourable performance of the proposed methods and the confidence measure.     

基于遗传算法的微分方程模型参数优化

针对采用传统方法求解动态系统的微分方程模型的参数存在的不足与困难,设计了一种改进的遗传算法优化模型的参数。计算实例表明,用遗传算法优化模型参数可以得到与实际数据更加吻合的数学模型。     

Invariant Sets in the Discrete Game of Retention

Differential games of retention are considered. Problems in a new game formulation under full sweeping condition are generalized. The problem of constructing minimum and maximum invariant sets of dynamic systems is analyzed. Two diametrically opposite examples are considered depending on the matrix of the discrete linear equation.__________Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 150–154, March–April 2005.     

Hierarchical parallelisation for the solution of stochastic finite element equations

As an example application the elliptic partial differential equation for steady groundwater flow is considered. Uncertainties in the conductivity may be quantified with a stochastic model. A discretisation by a Galerkin ansatz with tensor products of finite element functions in space and stochastic ansatz functions leads to a certain type of stochastic finite element system (SFEM). This yields a large system of equations with a particular structure. They can be efficiently solved by Krylov subspace methods, as here the main ingredient is the multiplication with the system matrix and the application of the preconditioner. We have implemented a “hierarchical parallel solver” on a distributed memory architecture for this. The multiplication and the preconditioning uses a—possibly parallel—deterministic solver for the spatial discretisation as a building block in a black-box fashion. This paper is concerned with a coarser grained level of parallelism resulting from the stochastic formulation. These coarser levels are implemented by running different instances of the deterministic solver in parallel. Different possibilities for the distribution of data are investigated, and the efficiencies determined. On up to 128 processors, systems with more than 5 × 10⁷ unknowns are solved.     

液化天然气(LNG)储存容器中的分层与翻滚

针对储罐中液化天然气（LNG）在温度差和密度差下的分层行为，建立LNG分层的异重流模型。并利用Lorenz方程描述异重流下层的热对流状态。采用耦合映象格子模型求解Lorenz方程，并引入对流强度量判断系统分层涡旋的产生和发展。对系统的数值模拟研究，确定了系统处于独立循环、分层翻滚及对流循环状态时对应的瑞利数Ra临界值。证明了系统在密度差趋于相等时，分界面被打破，LNG大量蒸发出现分层翻滚现象；并得到了系统随主要控制参数Ra的发展过程及分层翻滚发生的时间、高峰蒸发量等。计算表明：对于给定的密度差和温度差，底层的LNG厚度越大，则出现翻滚现象的时间越迟；底层厚度越大，高峰蒸发速度也越大，较易引发储罐超压；对于给定温度差，底层LNG密度较大时，出现翻滚的时间会相对提前。