Optimal policies for inventory systems with discretionary sales, random yield and lost sales

We determine replenishment and sales decisions jointly for an inventory system with random demand, lost sales and random yield. Demands in consecutive periods are independent random variables and their distributions are known. We incorporate discretionary sales, when inventory may be set aside to satisfy future demand even if some present demand may be lost. Our objective is to minimize the total discounted cost over the problem horizon by choosing an optimal replenishment and discretionary sales policy. We obtain the structure of the optimal replenishment and discretionary sales policy and show that the optimal policy for finite horizon problem converges to that of the infinite horizon problem. Moreover, we compare the optimal policy under random yield with that under certain yield, and show that the optimal order quantity （sales quantity） under random yield is more （less） than that under certain yield.     

偏远地区学生数学自主性学习方案分析

一、提出的背景乳源瑶族聚居在县境东北部和中部的崇山峻岭之中,瑶家村寨分布于茫茫群山之山顶、山腰、山坑、山窝和田峒之间,高度大多在海拔500米以上,一些村寨海拔达1000多米．瑶族人民历代散居于大山深处,基本靠刀耕火种及狩猎谋生．此种景况长此以往,造就了其在生产、生活等方面的互助友爱精神,并且世代相传．这种相对独立的生活虽经数十年的瑶汉文化的互通,但瑶族百姓在子女教育方面重视仍然不够,     

对于K2+Tm和完全图的Ramsey函数的渐近上界

本文研究了当n趋于无穷大时,关于K2+Tm和完全图Kn的Ramsey数的渐近上界,以及r(K2+Tm,Kn)和r(K1+Tm,Kn)的渐近关系.利用李雨生等人所给出的一个独立数的下界公式,给出了r(K4,Kn)和r(Kk-c,Kn)的渐近上下界,推广了李雨生等人所给出的r(K1+Tm,Kn)的下界.     

图与补图全独立数间的关系

对图G(V,E),V∪E中既不相邻、又不相关联的最大元素个数,称为G的全独立数,并简记为α_T(G)。本文研究了图和补图全独立数之间的关系,得到α_T(G) α_T(G~C)≤「3y 1/2」。其中y=|V(G)|,G~C是G的补图,「x」为不大于x的最大整数,且界可达。     

Uniform estimate for the tail probabilities of randomly weighted sums

Several authors have studied the uniform estimate for the tail probabilities of randomly weighted sumsa.ud their maxima. In this paper, we generalize their work to the situation thatis a sequence of upper tail asymptotically independent random variables with common distribution from the is a sequence of nonnegative random variables, independent of and satisfying some regular conditions. Moreover. no additional assumption is required on the dependence structureof {θi,i≥ 1）.     

PM2.5成因的逐步回归分析及治理方案研究

应用逐步回归分析方法获得了PM2.5与3个既与综合治理又与专项治理有关的因素SO_2、NO_2、PM10的最优二次回归方程,在将治理基准年与五年后目标的PM2.5浓度折算为对应的AQI指标之后,结合数据分析计算出了基准年的PM2.5、SO_2、NO_2、PM10这4个基准指标值.然后结合PM2.5综合治理与专项治理的费用经验公式,按照五年治理投入总经费最小的原则建立了一个标准的非线性规划模型,并求解出了最少的五年总投入经费及每年经费投入.对于指导PM2.5的治理工作有一定实际意义.     

Schur Convexity for Two Classes of Symmetric Functions and Their Applications

For x =(x1, x2, ···, xn) ∈ Rn+∪ Rn-, the symmetric functions Fn(x, r) and Gn(x, r) are defined by r1 + xFij n(x, r) = Fn(x1, x2, ···, xn; r) =x1≤iij1i2···ir ≤n j=1and r1- xGij n(x, r) = Gn(x1, x2, ···, xn; r) =,x1≤i1i2···ir ≤n j=1ij respectively, where r = 1, 2, ···, n, and i1, i2, ···, in are positive integers. In this paper,the Schur convexity of Fn(x, r) and Gn(x, r) are discussed. As applications, by a bijective transformation of independent variable for a Schur convex function, the authors obtain Schur convexity for some other symmetric functions, which subsumes the main results in recent literature; and by use of the theory of majorization establish some inequalities. In particular, the authors derive from the results of this paper the Weierstrass inequalities and the Ky Fan's inequality, and give a generalization of Safta's conjecture in the n-dimensional space and others.     

胡奋：向左走、向右走

哲学家说人生就是选择,这话在胡奋身上体现的淋漓尽致,正是因为有了人生中一个个或艰难或干脆的选择,才有了今天的胡奋——3M中国和3M香港首席财务及运营官,也是这家世界500强企业首位在中国大陆出生的董事。     

问诊集团财务治理

实务中,我国集团型企业在财务治理方面仍存在诸多问题,亟待解决、完善。 近年来,大型国有企业集团特别是中央企业的衍生金融业务损失问题、薪酬问题、＂地王＂问题、个别企业高管贪污腐败案件等广受社会议论。因此,建立和规范大型企业集团的公司治理结构,特别是集团财务治理结构,协调企业集团与各方利益相关者的关系,意义十分重大。     

打造名副其实的内审

近年来,企业内部审计作为完善的公司治理和高质量的财务报告信息的重要因素,受到越来越多的关注。但与此同时,我们看到实务中普遍存在的一些问题,严重影响了内审的效力。