A Note on “Economic Order Quantity under Conditions of Permissible Delay in Payments”

The problem of determining the economic order quantity under conditions of permissible delay has been recently analysed. This note analyses the same problem under assumptions of the ‘classical’ economic order quantity model, obtaining different results.     

经济订货批量公式的一个注解

本文讨论了不允许缺货和允许缺货存贮模型中经济订货批量公式,并建立了修正后的存贮模,给出了相应的经济订货批量公式。     

Time to Sell a Fixed Quantity of Stock Depleted by Distributed Demand

The probability density function of the time to sell a fixed quantity of stock depleted by a distributed demand is derived for block depletion and continuous depletion. The mean time to sell is obtained for (i) gamma-distributed demand and block depletion and (ii) normally distributed demand and continuous depletion.     

二阶微分算子的一个注记

此文利用黎曼几何的知识将二阶椭圆算子表示成为一个Schr(?)dinger算子．     

N个度量空间上的相关不动点的注记

得到了 n个度量空间上的相关不动点的几个结果 .     

修正单纯形法的计算量的注记

对文献［１］、［２］指出的修正单纯形法的计算量提出了异议,并给出了修正单纯形法应有的计算量。     

Fixed and Minimal Order Compensators

Given a time-invariant linear plant, the authors consider aminimal (or fixed) order compensator such that the (unity feedback)closed loop is stable with respect to a given region in thecomplex plane. The so-called critical constraint is used tofind points in the (parameter space) stability region. Thisenables some practical constraints to be added in the compensatordesign.     

A Note on Extremes of Concomitants of Order Statistics

Let be a sequence of identically distributed variables. We study the asymptotic distribution of , where Y _[r:n] denotes the concomitant of the rth order statistic X _r:n , corresponding to , and is held fixed while . Conditions are given for the and to have the same asymptotic behavior as that we would apply if were i.i.d. The result is illustrated with a simple linear regression model , where is a stationary sequence with extremal index .     

关于连续(开)序同态与分离性的一点注记

在L-拓扑空间中,给出连续序同态和开序同态的若干特征刻画,它们推广了文[2]的相应结果。此外,给出一个例子表明了分离性关系式:T-1 次T0/T0.     

A Note on Relative Efficiency of Axiom Systems

We introduce a notion of relative efficiency for axiom systems. Given an axiom system A_β for a theory T consistent with S¹₂, we show that the problem of deciding whether an axiom system A_α for the same theory is more efficient than A_β is II₂-hard. Several possibilities of speed-up of proofs are examined in relation to pairs of axiom systems A_α, A_β, with A_α ? A_β, both in the case of A_α, A_β having the same language, and in the case of the language of A_α extending that of A_β: in the latter case, letting Pr_α, Pr_β denote the theories axiomatized by A_α, A_β, respectively, and assuming Pr_α to be a conservative extension of Pr_β, we show that if A_α — A_β contains no nonlogical axioms, then A_α can only be a linear speed-up of A_β; otherwise, given any recursive function g and any A_β, there exists a finite extension A_α of A_β such that A_α is a speed-up of A_β with respect to g. Mathematics Subject Classification: 03F20, 03F30.     

A Note on the Oscillation of Second Order Differential Equations

We give a sufficient condition for the oscillation of linear homogeneous second order differential equation y + p(x)y + q(x)y = 0, where and is positive real number.     

Economic Order Quantity and Quantity Discounts under Date-terms Supplier Credit: A Discounted Cash Flow Approach

This paper examines economic order quantity and optimal order quantity under both all-units and incremental-quantity discounts when purchase cost, order cost, and carrying cost are all incurred on date-terms supplier credit. Payment dates for the three cost components need not be the same. The traditionally-used periodic-cost minimization methodology which is insensitive to differences in the timing of various within-period cash flows is replaced with a discounted cash flow methodology. Differences in the characteristics of day-terms and date-terms solutions to the quantity discount case are high-lighted.     

订货批量对牛鞭效应的影响分析

对于一个采用连续检查(s,S)订货策略的两级供应链,本文运用Markov链理论,通过对正则平稳Markov链行为特征的分析发现,即使不考虑需求预测方法,供货短缺,提前期和价格波动等因素,仅仅零售商的订货批量就能够产生牛鞭效应.研究结果表明,在需求分布和订货批量的变化范围满足一些条件时,减小订货批量有助于减弱牛鞭效应,从而提高供应链的运作效率.     

The Effect of Transfer-Pack Size on Order Quantity

In many stock-control systems the policy is to place an order if the stock balance has fallen to or below a reorder level and to order enough stock to bring the stock balance up to a maximum stock level. It is often the case that stock is sold singly but is replenished in multiples of some pack size. This note considers how the actual order size depends on the pack size and the amount by which the stock balance has fallen below the reorder level at the time an order is placed.     

具固定时刻的二阶脉冲微分系统零解的稳定性

利用脉冲微分不等式和分析技巧,构造Lyapunov函数给出了二阶具固定脉冲时刻的微分系统零解的稳定性的两个判定准则,特别突出了脉冲效应对系统稳定性的关键影响,并给出了其相关例子.     

Trade Credit and the Economic Order Quantity—A Further Extension

This paper extends the various contributions that have been made in this area, and in particular addresses the following issues: (i) why trade credit is granted, and the effect on the basic model where it is with-drawn; (ii) the legitimacy of certain assumptions in the various models which have been put forward to date; (iii) the interaction of other stockholding costs, such as storage and deterioration costs, with trade credit; (iv) the implications for stockholding where a business can sell goods acquired on credit for cash before the suppliers have to be paid and the order lead-time is less than the credit period. The paper also reviews whether trade credit should be included in the weighted cost of capital, and whether the holding-cost function should include interest received on the sale price, rather than cost.