n:k(m)交叉储备系统优化配置的仿真方法

由于缺乏有效的分析手段，非马尔可夫可修系统的优化配置非常困难，而仿真的方法往往工作量巨大。文中用排队网络模型给出n:k(m)交叉储备系统的通用仿真模型，在此基础上设计了求解系统在可靠度约束下最优配置问题的高效率的仿真算法，并给出若干优化配置问题的算例。本文中分别用解析的方法和仿真的方法计算了若干马尔可夫型n:k(m)系统的备件最优储备量，二者符合得很好。     

高炉设备系统可靠性建模与分析

本文对某冶金企业的高炉设备系统进行可靠性建模与分析,尤其是对m/n可修冷储备的分系统进行可靠性建模。这种系统是由n个部件组成,其中有m个部件在工作,k个部件备用(m+k=n),系统有且只有m个部件在工作系统才不会失效,在这里把这种系统叫做m/n冷储备系统,对于不同单元的可修冷储备系统目前尚无有效的方法确定其可靠性,本文应用马尔可夫过程,根据失效部件数量来对系统进行描述,给出了求解其可靠性的方法。     

ZnSe和ZnS干涉滤光片非线性光学双稳态的研究

本文提出了一种测定薄膜非线性参数(n, k)大小的简单方法.并且, 用所测得的ZnSe参数(n)为基础, 已经推导出对任何对称结构均适用的设计和计算干涉滤光片型双稳器件的程序.进而我们讨论了干涉滤光片的外部结构对双稳特性的影响.最后, 我们用实验测定了这种材料的双稳曲线.     

双零件族随机环境下可重构制造系统的生产能力设计

基于概率论、排队论与更新理论的方法,建立了双零件族随机市场需求模型与可重构制造系统的排队控制模型.以可重构制造系统的生产能力与开机数量为参数,基于重构成本、制造系统折旧成本与仓储成本,构建了平稳条件下可重构制造系统长期运行时,单位时间内所取得的平均利润优化模型,并提出了优化方法与步骤.通过求解该模型,得到了可重构制造系统的最优生产能力与最佳开机数量.基于求得的最优生产能力与最佳开机数量,给出了可重构制造系统的订单接受率与切换周期等性能指标.最后,用案例验证了所提方法的可行性.     

用于测量直流电阻标准的自动双源系统（英文）

介绍了一种通过双电流源电桥测量低欧姆标准电阻的新系统,用于1 mΩ～1Ω之间比率为1∶1的低阻值电阻测量。该电桥适用于没有低温电流比较器(CCC)或直流比较器(DCC)电桥的实验室。通过将电桥的实测值与另一种方法得到的未知电阻值进行比较,对电桥的性能进行了评价。该电桥对1 mΩ电阻的准确率达到10~(-5)级,对10 mΩ, 100 mΩ和1Ω电阻的准确率达到10~(-4)级。此外,利用双电压源系统测量了1 kΩ～100 MΩ的直流标准电阻。通过增加另一个数字万用表改进惠斯通电桥以同时测量未知电阻与标准电阻的比值对该系统性能进行了评价。将10 kΩ电阻用两种方法获得的测量值与实际值进行对比对该电桥进行了验证。除了1 kΩ电阻,电桥对其他电阻的准确率达到了10~(-6)级。此外,对电桥的不对称性也进行了评价。实验发现,不对称率对10 kΩ～100 MΩ的电阻为10~(-6)级,对1 kΩ的电阻为10~(-5)级。该电桥的操作由专门为此设计的LabVIEW程序进行计算机控制,并对所有测量结果的不确定度进行了评估。     

第九章 排队论(下)

§9.2 几种常用排队模型分析 由于输入过程、排队和服务规则以及服务机构的不同,实际中的排队问题是五花八门的。但大都可归纳到不同的排队模型中去分析。 在对排队模型进行分析时,都是在具体模型所表述的条件下,首先找出该系统在任意时刻t有n个顾客的概率P_n(t)。在稳态情况下,由于P_n(t)与t无关,故可简写成P_n,然后根据P_n和P_0(系统为空闲状态的概率)推算出反应系统运行特征的数量指标的计算公式。下面对几种常用的排队模型,将上述内容用表格形式给出(见表9.3) 为使表格简化,先将表9.3中模型——标准的M/M/1/∞/∞模型的具体条件说明如下: 该模型是指顾客到达的间隔时间和服务时间都服从负指数分布;顾客单个到来,相互独立,顾客源是无     

耦合系统的配对选择

本文通过对n输入,n输出的多变量耦合系统相对增益矩阵的分析,建立了n输入,n输出耦合系统的偶图模型,将图论的方法移植于耦合系统理论,用最优匹配的原理,给出了求取耦合系统最好配对的方法。     

QMS法研究反应动力学初探

选择具有一种气体产物i的溶液反应作为研究对象;使用AGA-100型四极质谱(QMS)仪跟踪检测反应在不同时间t时气体产物的浓度X_i,推导出了各级反应的X_i对t的函数关系式,从而找到了求取反应级数n与速度常数k的方法;通过测定不同温度下的k值还可以求出反应的表观活化能E_(?)。选择重氮盐Cl-N_2~ Cl~-的热致水解反应作为例子,用该法做了它的动力学研究,求出了n=1和k=5.41×10~(-4)S~(-1)(55℃)及E_(?)=8.05×10~4J·mol~(-1)。实验表明,所得结果与文献值一致,用QMS法进行反应动力学研究是可行的。     

战略后方仓库军用集装箱装运机械优化配置模拟仿真研究

以某战略后方仓库为例，通过构建1个包括龙门吊、集卡和跨运车的动态多级排队网络，运用仿真技术描述战略后方仓库集装箱装卸系统，对系统输出指标进行分析，给出了某战略后方仓库的最优机械配置比和最优的：龙门吊台数。     

一个不合格品率P计量单侧抽检方案制订问题的研讨

本文研究了产品特征X服从正态分布均方差未知时不合格品率p的计量单侧抽样检验的问题。提出了一种新的确定抽样方案(n,k)的方法。利用t分布表直接计算方案,未作分布上的任何近似处理,使得所得方案更加精确,特别是小批量时更是如此。得到了具有上规定限及下规限定的满足给定α、β、p_0、p_1要求的方案(n,k)的计算公式,并给出了制订方案的实例,还得到了方案(n,k)的抽检特性函数表达式。     

光仪标准件、常用件计算机辅助参数设计

本文在已引进软件S7k的基础上,提出了对光仪标准件、常用件的设计进行参数设计的设想,并对十四种标准件和四种常用件编写了应用程序,完成了部分标准件、常用件的参数化设计,对S7k进行了二次开发。本论文对计算机辅助绘图的进一步发展做了初步尝试。     

Nonconvex integer optimal robust impulsive control strategy for first-order piecewise finite precision nonlinear random early detection algorithm

There are two main contributions of this paper. First, this paper proposes a first-order piecewise finite precision nonlinear dynamical model for characterizing the average queue size of the random early detection (RED) algorithm. Second, this paper proposes a nonconvex integer optimal robust impulsive control strategy for stabilizing the average queue size. The objective of the control strategy is to determine the average queue size so that the average power of the impulsive control force is minimized subject to a constraint on the absolute difference between the actual average queue size and the theoretical average queue size at the equilibrium point. Computer numerical simulation results show that the proposed control strategy is effective and efficient for stabilizing the average queue size.     

Some comments on models for field enhancement

To estimate the apex field-enhancement factor gamma(a)associated with a pointed protrusion on a flat planar surface, the simple physical models of a 'floating sphere at emitter-plane potential' and a 'hemisphere on a post' are often discussed. The corresponding mathematical expressions have the form: gamma(a)=m+h/rho, where rho is the sphere or hemisphere radius, h is its 'height above the emitter plane', and m is a constant variously taken as 0, 2 or 3. Recent numerical simulations for the 'hemisphere on a post' model, reported elsewhere by two of us (CJE and GV) and by Kokkaris, Modinos and Xanthakis, have shown that all of these simple formulae significantly overpredict gamma(a) if h/rho is large. This article first reexamines the basis of these simple formulae and confirms that they are less secure than is sometimes thought. The formulae reported elsewhere as fits to the numerical results are then quoted and compared with the simple formulae, and with the known exact analytical result for the 'hemi-ellipsoid on a plane' model. Discrepancies can be rationalised. Some general conclusions are drawn.     

考虑需求信息更新的易逝品的订货策略

易逝品供应链管理的一个核心问题是，零售商如何根据制造商提供的订货条件进行合理订货。研究了考虑顾客需求信息更新的易逝品的零售商订货策略，制造商通过为零售商提供两次订货机会，以实现制造商和零售商的共赢。通过对开始时刻和顾客需求信息更新后的系统进行建模和讨论，得到了在两次订货条件下零售商应该采取的最优的订货与调整策略。     

Comparison of piezoelectronic networks acting as distributed vibration absorbers

Electric vibration absorbers made of distributed piezoelectric devices for the control of beam vibrations are studied. The absorbers are obtained by interconnecting an array of piezoelectric transducers uniformly distributed on a beam with different modular electric networks. Five different topologies are considered and their damping performance is analysed and compared. Their optimal parameters are found by adopting a criterion for critical damping of k̄-waves: the parameters are suitably chosen to have the quickest temporal vibration decay for a single wave number k̄. The analysis is based on homogenized models of the modular piezo-electromechanical systems, i.e. they are regarded as continuous systems by assuming that the number of modules per unit length is high enough with respect to the considered wave numbers. Calling k̄ -absorbers the corresponding optimal absorbers, we show that: (i) k̄-waves are damped in k̄-absorbers with an optimal decay time which is independent of the absorber interconnecting topology, while it depends only on the piezoelectric coupling coefficient; (ii) the efficiency of k̄-absorbers depends significantly on the absorber interconnecting topology for k different from k̄; (iii) one of the proposed absorbers (which is made of a fourth-order electric transmission line with a second-order electric dissipation) equally performs for all the wave numbers and accomplishes an effective multi-modal damping for the mechanically forced response; (iv) the optimal values of the electric parameters differently depend on the number n of used circuit modules for different interconnecting topologies and, in particular, the optimal inductance per module needed in a fourth-order electric transmission line is proportional 1/n³.     

A queueing system with inventory and mixed exponentially distributed lead times

We consider M/M/1/∞ systems with inventory in which completing each service in the queueing system requires an on-hand inventory. Continuous review (r, Q) policy is considered for the inventory system, and lead times are assumed to be mixed exponentially distributed. During stockout, arriving demands get rejected from the queue and become lost (lost sale situation). We derive stationary distribution of product form of joint queue length and on-hand inventory. The resulting distribution is employed to compute performance measures which can be used to derive the optimal policy. Optimal order size for predetermined reorder policy is initially determined and finally, optimal reorder point and corresponding optimal order size are simultaneously computed for several numerical examples.     

Minimizing total flow time for the worker assignment scheduling problem in the identical parallel-machine models

The worker assignment scheduling problem consists of two basic questions of job scheduling and worker assignment. In this study, only the performance measure of total flow time is investigated in the model of identical parallel-machine with nonpreemptive jobs. Because the worker assignment scheduling problem in this specific model can be shown as NP-complete, heuristics have been developed for minimizing the total flow time. This selected worker assignment scheduling problem is solved in two stages of job scheduling and worker assignment. The shortest processing time for A_i part (SPT-A) heuristic is used for the stage of job scheduling. For the stage of worker assignment, the largest marginal contribution (LMC) procedure is used to minimize the total flow time. Two 100 I/P/n/m/W problems were simulated; results obtained by the heuristics are either optimal or near optimal. In conclusion, the heuristics developed have shown very impressive results quite efficiently.     

一种系统预防性维修的综合优化决策

研究了预防更换周期和备件贮备量的综合优化决策问题。建立了系统平均运行周期模型和一个周期的平均期望损失模型 ,并以单位时间的期望损失为目标确定最佳的更换周期和最佳的备件贮备量 ,给出一种优化决策算法