用正交试验设计法寻找碳氮共渗最佳工艺

我厂是批量生产装载机和铲车的专业工厂.其产品变速、传动的主要部件齿轮和轴类工件在设计中都采用工艺特性较好的20CrMnTi 合金钢结构,并通过热处理以进一步提高它们的机械性能.为了不断提高产品质量,在原有的渗碳工艺基础上,我们正在探索采用碳氨共渗这个国内目前较为先进的新工艺.新工艺共分升温、排气、共渗、扩散四个阶段.实验证明每个阶段的温度、时间、炉压、煤油和氨气通入量的变动对试验结果的关系均为各种不同的曲线.此外,装炉的方式、装炉量的多少、炉子延续使用次数的多少都会影响试验的结果.基于工厂现有技术条件,对试验结果要求     

多目标决策二级模糊优选模型

研究了近年来多目标决策系统模糊优选理论的发展状况,基于一种新的目标函数,给出了求解最优优属度与最优指标权重的模糊迭代算法;依据“数字-信息-知识”的思维,从系统的稳定性和可靠性角度,对原始数据进行信息挖掘,提出了二级模糊优选理论模型,进一步丰富了模糊优选理论模型.将提出的模糊决策模型应用于1 6家电炉炼钢企业的模糊综合评价决策,取得了较为满意的结果.     

保结构算法的相位误差分析及其修正

辛算法和保能量算法是应用最为广泛的两种保结构算法.本文从相位误差的角度给出了他们的比较结果.我们针对线性动力系统,分别分析了基于Pade对角逼近给出的辛算法和基于平均向量场法得到的能量守恒算法的相位误差,并通过数值验证了分析结果.文章还给出了保结构算法相位误差的改进方法,并通过数值例子验证了方法的有效性.     

非光滑牛顿算法的收敛性

该文研究了求解包含问题的非光滑牛顿算法的收敛性.运用度量正则性条件,证明了非光滑牛顿算法的一个局部收敛性结果,该结果通过利用非紧性测度,削弱了已有相关结果的假设条件.此外,得到了非光滑牛顿算法的一个全局情形的收敛性结果,即所需条件均假设于算法的初始点而非包含问题的解点.     

道路交通拥堵自动检测的改进加州算法及仿真

本文研究了高速公路交通拥堵自动检测算法.利用改进的加州算法,获得了用VISSIM软件对高速公路车流量情况的仿真数据及结果,仿真结果表明改进加州算法的检测结果良好.     

矩阵填充的硬阈值修正算法

提出了使用硬阈值进行矩阵填充的修正算法.算法通过对迭代矩阵进行对角修正来完成矩阵填充,并给出了算法的收敛性分析.最后通过数值实验比较了修正算法与硬阈值算法填充的数值结果,显示出了新算法的优越性.     

一类拟变分包含问题带误差的迭代算法

本文研究了一类带误差的拟变分包含问题的迭代算法.利用黏性逼近法,获得了拟变分包含问题的迭代算法的强收敛结果,将最近一些文献的相应结果从迭代算法推广到带误差的迭代算法.     

一致连续的伪单调变分不等式问题的外梯度投影算法

考虑了经典变分不等式问题的外梯度投影算法.基于Fan和Qin提出的带惯性项的外梯度投影算法,在映射是伪单调和一致连续的假设下,证明了算法弱收敛到变分不等式问题的解.同时,数值实验验证了算法的适用性.所得结果改进和推广了最新文献中主要结果.     

学习算法的稳定性与泛化(Ⅱ):有界差分稳定框架

根据有界差分条件,提出了学习算法的有界差分稳定框架.依据新框架,研究了机器学习阈值选择算法,再生核Hilbert空间中的正则化学习算法,Ranking学习算法和Bagging算法,证明了对应学习算法的有界差分稳定性.所获结果断言了这些算法均具有有界差分稳定性,从而为这些算法的应用奠定了理论基础.     

弱相对非扩张映像不动点单调CQ算法与应用

Kamimura和Takahashi$^{[7]}$证明了相对非扩张映像CQ迭代算法的强收敛定理.该文构造了单调CQ算法, 用来逼近弱相对非扩张映像不动点, 证明了强收敛定理. 并将结果应用于逼近Banach空间极大单调算子的零点. 单调CQ算法比目前的CQ算法收敛速度快. 另外, 为证明弱相对非扩张映像不动点强收敛定理,该文运用了新的Cauchy列证明方法, 而不用Kadec-Klee性质, 该文结果改进了S.Matsushita 和 W.Takahashi及其它人的结果.     

多时段EOQ存贮问题一种策略的改进优化方法

本文对多时段费用变动型存贮问题的一种策略提出了改进优化方法.理论分 析和实证比较表明:改进方法较原方法不但费用更低,而且算法简便直观,适用性强.     

The Computational Complexity of Extrapolation Methods

This paper analyzes the cost of extrapolation methods for non-stiff ordinary differential equations depending on the number of digits of accuracy requested. Extrapolation of the explicit midpoint rule is applied for various number sequences. We show that for sequences with arithmetic growth, the cost of the method is polynomial in the number of digits of accuracy, while for sequences of numbers with geometric growth, the cost is super-polynomial with respect to the same parameter.     

Fuzzy strategic replacement analysis

This paper presents a fuzzy methodology for replacement of equipment. Issues such as fuzzy modeling of degradation parameters and determining fuzzy strategic replacement and economic lives are extensively discussed. For the strategic purpose, addible market and cost effects from the replacements against the counterpart, i.e., the existing equipment cost and market obsolescence, are modeled fuzzily and interactively, in addition to the equipment deterioration. Both the standard fuzzy arithmetic and here re-termed requisite-constraint vertex fuzzy arithmetic (or the vertex method) are applied and investigated. Two numerical examples and the results are provided.     

多资源复杂网络的应急调度研究

以一次性消耗系统为背景．提出了多应急点多出救点以及多资源的复杂网络应急调度模型。以应急点的损失最小和出救点的个数最少为目标,将损失量大小转化为应急时间长短进行衡量,运用理想点法求解。最后构造算例．运用本文提出的方法对模型进行计算,验证了所建立模型的合理性及理想点法的可行性和有效性。     

An infinite precision bracketing algorithm with guaranteed convergence

The computational cost of a bracketing algorithm in the bit model of computation is analyzed, when working with a finite arithmetic of unbounded accuracy. The complexity measure used here is the number of bit operations, seen as a function of the required absolute error of the result. In this model the convergence of the classical bisection method (as well as that of any bracketing method which requires the function sign) is not ensured when no information on the behaviour of the function is available. A modified bisection algorithm with guaranteed convergence is proposed and an upper bound to its computational cost is given.     

拆解中心的选址决策研究

针对拆解中心选址决策问题,考虑到检测中心到拆解中心和用户的运输容量,基于成本最小原则,建立了备选拆解中心选址的优化模型,并提出了求解算法,最后通过算例说明了方法的可行性.     

Efficient orthogonal matrix polynomial based method for computing matrix exponential

The matrix exponential plays a fundamental role in the solution of differential systems which appear in different science fields. This paper presents an efficient method for computing matrix exponentials based on Hermite matrix polynomial expansions. Hermite series truncation together with scaling and squaring and the application of floating point arithmetic bounds to the intermediate results provide excellent accuracy results compared with the best acknowledged computational methods. A backward-error analysis of the approximation in exact arithmetic is given. This analysis is used to provide a theoretical estimate for the optimal scaling of matrices. Two algorithms based on this method have been implemented as MATLAB functions. They have been compared with MATLAB functions funm and expm obtaining greater accuracy in the majority of tests. A careful cost comparison analysis with expm is provided showing that the proposed algorithms have lower maximum cost for some matrix norm intervals. Numerical tests show that the application of floating point arithmetic bounds to the intermediate results may reduce considerably computational costs, reaching in numerical tests relative higher average costs than expm of only 4.43% for the final Hermite selected order, and obtaining better accuracy results in the 77.36% of the test matrices. The MATLAB implementation of the best Hermite matrix polynomial based algorithm has been made available online.     

提前期为正态分布下的单、双源供应商成本模型

提前期是供应链管理研究中一个重要的内容，有关提前期内需求模型方面的研究层出不穷，但关于提前期本身变化的研究并不多见。本文运用分析每期货物相关成本的方法，推导建立了提前期为正态分布时的单、双源供应商成本模型，然后进行了比较分析。最后，证明了模型最优解的存在，并给出了求解的算法。     

Towards a strongly polynomial algorithm for strictly convex quadratic programs: An extension of Tardos' algorithm

In a recent paper Tardos described a polynomial algorithm for solving linear programming problems in which the number of arithmetic steps depends only on the size of the numbers in the constraint matrix and is independent of the size of the numbers in the right hand side and the cost coefficients. In this paper we extend Tardos' results and present a polynomial algorithm for solving strictly convex quadratic programming problems in which the number of arithmetic steps is independent of the size of the numbers in the right hand side and the linear cost coefficients.This research was partially supported by the Natural Sciences and Engineering Research Council of Canada Grant 5-83998.     

Cost colourings of hypergraphs

Some aspects of the cost colouring of hypergraphs are considered in the paper. A generalisation of the well-known Brook's theorem for a cost colouring of hypergraphs is proved. Moreover, a relation between the minimal cost of a colouring of a hypergraph with a set of costs which produce an arithmetic sequence and a number of edges of this hypergraph is investigated.