有供应方限制的临时价格折扣与最优存贮模型

供应方提供临时价格折扣，一般都附带特别定货量限制。购买方可在所提供折扣价格条件下从有限种订货量中选择最小的订货量，但不一定是最优订货量。本文提出有供应方限制的临时价格折扣条件下的最优存贮模型和订货策略。并给出应用实例。     

Weak Noether symmetry for nonholonomic systems of non-Chetaev type

Based on the weak Noether symmetry proposed by Mei F X, this paper discusses the weak Noether symmetry for nonholonomic system of non-Chetaev type, and presents expressions of three kinds of conserved quantities by weak Noether symmetry. Finally, the application of this new results is showed by a practical example.     

Hojman conserved quantity deduced by weak Noether symmetry for Lagrange systems

This paper studies the Hojman conserved quantity, a non-Noether conserved quantity, deduced by special weak Noether symmetry for Lagrange systems. Under special infinitesimal transformations in which the time is not variable, its criterion is given and a method of how to seek the Hojman conserved quantity is presented. A Hojman conserved quantity can be found by using the special weak Noether symmetry.     

基于改进SUSAN算法的箭环目标跟踪与测量

针对发射场火箭初始段漂移量的测量，提出一种带灰度梯度方向的SUSAN算子，实现了基于该算子与变模板相关跟踪算法的目标跟踪测量方法.首先在SUSAN特征检测原则的基础上，将对角点的检测转化为对边缘的检测，同时记录梯度方向，在剔除了图像噪音点之后，由具有特定方向信息的边缘像素点精确定位角点的坐标.该方法克服了标准SUSAN算法准确度低的弊病，使得对目标的提取准确度可以达到亚像素级，并增强了抗噪性能，实验证明该算法提取准确性高，运算量小，易于实现.     

问题讨论与思考工作曲线定量计算中的方法与误差

工作曲线法在科学定量分析中非常重要。然而如何充分利用测量值数据以工作曲线法进行计算从而得到最精确的结果是值得探讨的问题。尤其是对于利用工作曲线获取中间结果并进行进一步计算时,不同的计算方法会导致不同的误差。本文归纳提出4类主要方法,即“直接平均法”“加权平均法”“二次回归法”“共回归法”,通过理论分析并实例计算以比较其精度与误差。同时,对其各自的优缺点和适用范围进行了系统性分析,希对广大师生的教学与科研有所启发。     

Birkhoff系统的一类新型守恒量

给出了Birkhoff系统的一类新型守恒量。首先,建立了Birkhoff系统的运动方程及其Mei对称性的定义和判据;其次,给出了系统的一类新型守恒量的存在定理,并导出了用于确定无限小生成元的广义Killing方程;最后,建立了守恒定理的逆定理     

Optimizing inventory decisions in a two-level supply chain with order quantity constraints

A fundamental assumption in traditional inventory models is that all of the ordered items are of perfect quality. A two-level supply chain is considered consists of one retailer and a collection of suppliers that operate within a finite planning horizon, including multiple periods, and a model is formulated that simultaneously determines both supplier selection and inventory allocation problems in the supply chain. It is supposed that the ordered products dependent on the suppliers include a certain percentage of imperfect quality products and have different prices. In this paper, we study the impact of the retailer’s financial constraint. On the other hand, suppliers have restricted capacities and set minimum order quantity (MOQ) policy for the retailer’s order amount happened in each period. So, the problem is modeled as a mixed integer nonlinear programming. The purpose of this model is to maximize the total profit. The nutrients, fishery and fruitage industries give good examples for the proposed model. A numerical example is presented to indicate the efficiency of the proposed model. Considering the complexity of the model, a genetic algorithm (GA) is presented to solve the model. We demonstrate analytically that the proposed genetic algorithm is suitable in the feasible situations.     

相对运动变质量力学系统Appell方程的广义Lie对称性导致的广义Hojman守恒量

研究相对运动变质量完整系统Appell方程的广义Lie对称性及其直接导致的广义Hojman守恒量.在群的无限小变换下,给出相对运动变质量完整系统Appell方程广义Lie对称性的确定方程;得到相对运动变质量完整系统Appell方程广义Lie对称性直接导致的广义Hojman守恒量的表达式.最后,利用本文结果研究相对运动变质量完整约束的三自由度力学系统问题.     

相空间中相对运动完整力学系统的共形不变性与守恒量

研究了相空间中相对运动完整力学系统的共形不变性与守恒量.给出了该系统共形不变性的定义,并推导出相空间中相对运动完整力学系统的运动微分方程具有共形不变性并且是Lie对称性的充分必要条件.利用规范函数满足的结构方程导出该系统相应的守恒量,并给出应用算例.     

Noether symmetries and conserved quantities for spaces with a section of zero curvature

In an earlier paper (Feroze, 2010 [21]), the existence of new conserved quantities (Noether invariants) for spaces of different curvatures was discussed. There, it was conjectured that the number of new conserved quantities for spaces with an m$m$-dimensional section of zero curvature is m$m$. Here, along with the proof of this conjecture, the form of the new conserved quantities is also presented. For the illustration of the theorem, an example of conformally flat spacetime is constructed which also demonstrates that the conformal Killing vectors (CKVs), in general, are not symmetries of the Lagrangian for the geodesic equation.