串行离散事件动态系统的建模,分析及设计

本文提出的离散事件动态系统（ＤＥＤＳ）建模新方法，是从Ｋ＋１个缓冲库状态中抽取有库存（Ｐｏ）和有空位（Ｐｋ）两种状态，合并到邻近的工作站中，构成相应的等效工作站，再将所有等效工作站联成ＤＥＤＳ生产系统，从而导出各项生产指标．这种方法是将离散断续工作的多级生产线转化为连续工作的多级生产线，于是可以采用常微分方程数学工具，得出静态和动态的精确分析解，较好地解决了离散断续工作系统建模的难题。     

计算机集成制造系统(CIMS)的可靠性建模与分析

针对CIMS生产线的一般结构,并有工作站不可靠、有多种运行方式及有限缓冲库等特 点,依据工作站的实际平均加工时间,提出了一种新的可靠性建模和分析方法.计算示例表 明,这种方法较现有的方法适用面广,且计算量小.     

级联生产线的可靠性分析

本文用流平衡法建立级联生产线的可告性模型，较好地解决了多级可修生产线的可靠性分析这一难题，理论结果和数值分析表明，流平衡法和文献［１］的等效工作站法有一致的结果。     

带有缓冲库的综合制造系统(CIMS)分析及其可靠性的研究

本文对带有中间缓冲库的可修CIMS可靠性进行了深入系统的研究.中间库是将刚性联 结生产线进行柔性化的手段,是提高系统可靠性和生产率的有效措施.另一方面,工作站的维 修也能起到同等重要的作用.但这样组成的大系统存在生产线的畅通、生产率的协调等问题, 给系统可靠性与优化设计造成了很大的困难,长期以来没有得到很好的解决. 本文从马尔可夫过程的排队论出发,运用系统可靠性理论,对缓冲库、工作站及系统进行 分步分析,综合求解,从而得出一条工件流平衡定理,解决了各站之间生产率丢失的问题,并给 出了系统可靠性的有关指标.     

考虑一类运行规则的两级生产线的可靠性分析

考虑运行规则的两级生产线的可靠性问题是加工系统中很重要的一类,本文对机器、缓冲 区及生产线的运行状态进行了深入的讨论,从机理上分析了生产线运行的状况,求出了机器在 正常和失效状态下的概率以及缓冲区处于不空状态下的概率,得到了分析这类问题的可靠性 指标.     

非串行CIMS生产线可靠性建模、分析与综合

采用等效工作站方法,对非串行CIMS生产线可靠性进行了研究,得到了一条缓冲库可 用度的定理,并推导出在稳态情况下,非串行CIMS系统(如装配线和拆卸线)可以转变成串 行系统求解.同时分析出加工过程不丢失工件的充要条件和若干必要条件,绘出一幅PK-K 曲线,可以给出可行解的大致范围,有助于具体问题的求解.     

多级CIMS生产线的可靠性分析

本文对带有缓冲区的可修的多级 CIMS 串行生产线的可靠性问题进行了研究.用马氏过程对中间工作站及中间缓冲区的状态进行了分析,得到了生产线的稳态可用度和稳态生产率的解析式,并用一个例子进行了说明.     

CIMS串行生产线可靠性建模与分析的研究

本文对CIMS串行生产线可靠性建模与分析进行了综述，对两级和多级串行生产线的问题进行了讨论和分析，提出了ＣＩＭＳ可靠性研究的一些问题。     

DiffServ模型中的多级主动缓冲管理算法

根据DiffServ模型实现的需要，在分析现有缓冲管理算法的基础上，提出了QPRED和VPRED多级主动缓冲管理算法，这两种算法在分组分类的粒度上提供了分级的缓冲管理能力，并将每一类分组的缓冲状态（缓冲字节数或缓冲平均队列长度）引入到了分组丢弃概率的计算中，同时结合优先级因子实现了类和类之间在优先级意义上的公平性，与现有的缓冲管理算法相比，QPRED和VPRED多级主动缓冲管理算法更适合于DiffServ模型的要求。     

QPRED:一种公平多级主动缓冲管理算法

DiffServ模型是当前实现IP QoS的体系结构之一，在其实现中，缓冲管理技术是很重要的一个方面．根据：DiffServ模型实现的需要，在分析现有缓冲管理算法的基础上，提出了QPRED多级主动缓冲管理算法，这种算法在分组分类的粒度上提供了分级的缓冲管理能力，并将每一类分组的缓冲状态引入到了分组丢弃概率的计算中，同时结合优先级因子实现了类和类之间在优先级意义上的公平性．通过分析和仿真，证明了QPRED算法的性能．与现有的缓冲管理算法相比，QPRED多级主动缓冲管理算法更适合于DiffServ模型的要求．     

Linear state estimation for Markov jump linear system with multi-channel observation delays and packet dropouts

This paper is to investigate the linear minimum mean square error estimation for Markovian jump linear system subject to unknown Markov chains, multi-channel mode and observation delays, and packet losses. The reorganisation method is employed to convert the delayed measurement system into an equivalent delay-free one and a new state variable is introduced, by which the original state estimation with transmission delays and data losses is transformed into the new state estimation for the reorganised delay-free system with jumping parameters and multiplicative noises. The new state estimation is derived via the innovation analysis method, and an analytical solution to the estimator is given in terms of a set of generalised Riccati difference equations based on a set of coupled Lyapunov equations. Then the original state estimation will be obtained via the jumping property. Finally, we show that the difference Riccati equations converge to a set of generalised algebraic Riccati equations under appropriate assumptions, which result in an optimal stationary filter.     

A new method to optimize the satellite broadcasting schedules usingthe mean field annealing of a Hopfield neural network

Reports a new method for optimizing satellite broadcasting schedules based on the Hopfield neural model in combination with the mean field annealing theory. A clamping technique is used with an associative matrix, thus reducing the dimensions of the solution space. A formula for estimating the critical temperature for the mean field annealing procedure is derived, hence enabling the updating of the mean field theory equations to be more economical. Several factors on the numerical implementation of the mean field equations using a straightforward iteration method that may cause divergence are discussed; methods to avoid this kind of divergence are also proposed. Excellent results are consistently found for problems of various sizes.     

A wavelet approach for the multi-term time fractional diffusion-wave equation

In this paper, a Galerkin method based on the second kind Chebyshev wavelets (SKCWs) is established for solving the multi-term time fractional diffusion-wave equation. To do this, a new operational matrix of fractional integration for the SKCWs must be derived and in order to improve the computational efficiency, the hat functions are proposed to create a general procedure for constructing this matrix. Implementation of these wavelet basis functions and their operational matrix of fractional integration simplifies the problem under consideration to a system of linear algebraic equations, which greatly decreases the computational cost for finding an approximate solution. The main privilege of the proposed method is adjusting the initial and boundary conditions in the final system automatically. Theoretical error and convergence analysis of the SKCWs expansion approve the reliability of the approach. Also, numerical investigation reveals the applicability and accuracy of the presented method.     

Annealing by two sets of interactive dynamics

This work derives the mean field approximation to the mean configuration of a stochastic Hopfield neural network under the Boltzmann assumption. The new approximation is realized by two sets of interactive mean field equations, respectively estimating mean activations subject to mean correlations and mean correlations subject to mean activations. The two sets of interactive dynamics are derived based on two dual mathematical frameworks. Each aims to optimize the objective quantified by a combiation of the Kullback-Leibler (KL) divergence and the correlation strength between any two distinct fluctuated variables subject to fixed mean correlations or activations. The new method is applied to the graph bisection problem. By numerical simulations, we show that the new method effectively improves in both performance and relaxation efficiency against the naive mean field equation     

一种基于噪声子空间的半盲信道辨识算法

传统确定性半盲算法在最优权值选择上效率较低。为此,提出一种基于噪声子空间的半盲方法。利用噪声子空间与信号子空间的正交关系,构建信道响应与噪声矢量间的约束,根据参考符号与对应接收信号间的卷积关系建立额外的约束,由最小二乘方法求解信道冲激响应。仿真实验验证了该算法的有效性及参考符号个数下限的正确性。     

A new Wavelet Method for Variable‐Order Fractional Optimal Control Problems

In this paper, a new computational method based on the Legendre wavelets (LWs) is proposed for solving a class of variable‐order fractional optimal control problems (V‐FOCPs). To do this, a new operational matrix of variable‐order fractional integration (OMV‐FI) in the Riemann‐Liouville sense for the LWs is derived and used to obtain an approximate solution for the problem under study. Along the way the hat functions (HFs) are introduced and employed to derive a general procedure to compute this matrix. In the proposed method, the variable‐order fractional dynamical system is transformed to an equivalent variable‐order fractional integro‐differential dynamical system, at first. Then, the highest integer order of the derivative of the state variable and the control variable are expanded by the LWs with unknown coefficients. Next, the OMV‐FI in the the Riemann‐Liouville sense together with some properties of the LWs are employed to achieve a nonlinear algebraic equation in place of the performance index and a nonlinear system of algebraic equations in place of the dynamical system in terms of the unknown coefficients. Finally, the method of constrained extremum is applied which consists of adjoining the constraint equations derived from the given dynamical system to the performance index by a set of undetermined Lagrange multipliers. As a result, the necessary conditions of optimality are derived as a system of algebraic equations in the unknown coefficients of the state variable, control variable and Lagrange multipliers. Furthermore, the efficiency and accuracy of the proposed method are demonstrated for some concrete examples. The obtained results show that the proposed method is very efficient and accurate.     

Numerical analysis of confined turbulent flow

This work outlines a second order accurate, coupled, conservative new numerical scheme for solving a two dimensional incompressible turbulent flow filed. Mean vorticity, ω, and mean stream function, ψ, are used as the mean flow dependent variables. The turbulent kinetic energy $\text{k}$ and the turbulent energy decay rate, ?, are used to define the turbulent state. In the present computational scheme two systems of equations and variables are considered: the mean flow system, ψ-ω, and the turbulent state system, $\text{k-?}$. Every system is solved implicity in a coupled double loop manner, and all the flow equations are solved iteratively in the global sense. Since the turbulence boundary conditions have a non-regular variation near a solid wall, they are coupled to the equations implicitly in both systems. In this way the numerical instabilities due to the irregular form of the equations near the solid walls are suppressed. The rate of convergence of the new numerical scheme of the coupled systems ψ-ω and $\text{k-?}$ is twice that realized when solving these equations separately. The necessary conditions for convergence of the numerical equations are investigated as well as the rate of convergence features. The detailed stability conditions are derived. As an example, the axisymmetric mixing of two confined jets with an internal heat source is considered with this numerical scheme.     

6R关节型机器人运动学建模

为满足新开发的多机器人实验系统编程需要,研究了6R机器人运动学逆解问题.推导了代数逆解结果,并研究了将其用于实际控制系统时,逆解的漏解、增根和多解问题.与传统方法比较,采用了便于程序模块化的坐标系设置方式,在需要经常更换作业工具的多机器人系统中更为适用.推导过程只需2次矩阵逆乘,步骤简单.基于VC++和OpenGL技术编制了系统程序,检验了方法的有效性.以其中一个位姿为例,对比几何方法得出的结果,验证了算法的正确性.研究的结果适用于MOTOMAN-UP6和PUMA560等相似构型的所有机器人.     

Periodic impulse-forcing of non-linear systems: a new method

A new method is developed that allows one to determine the performance of a nonlinear system undergoing impulse-forcing analytically. The method is based on the Carleman linearization procedure, which approximates a non-linear system of equations and a non-linear performance-measure by a linear system of higher order. A general explicit formula is derived which allows the determination of the state equations and of the performance measure as a function of the forcing period. An example illustrates the new method.