Sum,product and ratio of Pareto and gamma variables

The exact distributions of X+Y, X Y and X/(X+Y) are studied when X and Y are independent Pareto and gamma random variables. Applications are discussed, to real problems in clinical trials, computer networks and economics.     

STOCHASTIC COST-VOLUME-PROFIT ANALYSIS IN A COMPETITIVE OLIGOPOLY

Previous stochastic cost-volume-profit (CVP) models have assumed that the firm was operating under either perfect competition or monopolistic conditions. This paper presents a stochastic CVP model applicable to oligopolistic competition. Each firm is assumed to maximize a linear function of the expected value and the standard deviation of its random profits. The result is a game-theoretic model that is solved using the concept of a Nash equilibrium. The results of the model are used to examine a firm's competitive strength. The model can be easily modified to accommodate a measure of risk based on the capital asset pricing theory.     

A study on cyclic bandwidth sum

Suppose G is a graph of p vertices. A proper labeling f of G is a one-to-one mapping f:V(G)→{1,2,…,p}. The cyclic bandwidth sum of G with respect to f is defined by CBS _f (G)=∑ _uv∈E(G)|f(v)−f(u)| _p , where |x| _p =min {|x|,p−|x|}. The cyclic bandwidth sum of G is defined by CBS(G)=min {CBS _f (G): f is a proper labeling of G}. The bandwidth sum of G with respect to f is defined by BS _f (G)=∑ _uv∈E(G)|f(v)−f(u)|. The bandwidth sum of G is defined by BS(G)=min {BS _f (G): f is a proper labeling of G}. In this paper, we give a necessary and sufficient condition for BS(G)=CBS(G), and use this to show that BS(T)=CBS(T) when T is a tree. We also find cyclic bandwidth sums of complete bipartite graphs. Dedicated to Professor Frank K. Hwang on the occasion of his 65th birthday. Supported in part by the National Science Council under grants NSC91-2115-M-156-001.     

对零势点选择若干问题的探讨

讨论几种典型电场的零势点位置的确定 ,说明选择零势点的原则     

英语中零冠词的使用

根据信息交换三要素原则，从词汇意义的层面及语言及其所指的角度出发，重点探讨英语中零冠词的用法．     

钢筋混凝土空心剪力墙的拓扑优化设计

传统现浇钢筋混凝土剪力墙结构具有自重大、刚度大、抗震作用大、延性差以及保温隔热性能低等建筑节能性能差等等诸多的缺点.随着建筑业的迅猛发展,大量的试验研究和有限元计算分析表明：钢筋混凝土空心剪力墙刚度小,延性好,是一种很好的节能性的延性剪力墙结构,更适用于高层建筑.本文主要利用ANSYS的结构拓扑优化模块对钢筋混凝土空心剪力墙的拓扑形状进行结构优化设计,建立以总体积为目标函数,以应力和变形状态变量为约束条件,以空心剪力墙孔洞的直径为优化变量的钢筋混凝土空心剪力墙的优化设计模型,并采用零阶方法进行优化设计和计算.     

TN-C-S供电系统

三相低压供电系统零线断线及施工误接线经常造成电压偏移而导致大面积烧毁用户用电器的事故,给国家和用户造成经济损失。为避免该类事故的发生,采用新型的具有保护零线断线保护功能的断路器是非常有益的。     

我国商业银行小额账户收费动因研究

2005年以来,我国主要商业银行相继出台了小额账户清理和收费措施,本文首先分析清理小额账户的直接动机,进而通过中美两国银行业数据进行比较,运用理论阐述和实证分析说明小额账户政策调整的深层次原因在于减小系统压力、改善银行收入结构和分散风险,并提出了小额账户收费改革中可能面临的问题及解决对策。     

欧拉函数φ（n）的两个估计式

探讨了当ｘ≥１，ｋ为负整数时，欧拉函数的ｋ次方和的估计式，并得到欧拉函数对数和的估计式，式中为素数，求和号下的ｐ过全体素数，，式中为素数，求和号下的ｐ过全体素数。