改进后的PERT方法在进度风险分析中的应用

风险分析是进度控制中的重要内容。针对经典PERT网络的假设和计算过程,分析出它存在的三方面缺陷。并提出解决问题的三种具体措施,从概率论与数理统计的角度,对关键线路和关键工作进行了重新定义和确定的方法。     

烧结模糊控制系统的设计与实现

设计了一个烧结模糊控制系统，进而构建了一个基于模糊控制的自适应脉宽控制器，对煤气阀、换向阀开关时间进行控制；利用模糊控制器的模糊推理能力来实现煤气阀门开度在线调整，以达到优化控制的目的。运行结果表明，这种控制器与常规比值控制器相比可以取得较好的控制效果。     

Contract modifications and the basis behavior of live cattle futures

The purpose of this study was to assess the basis behavior of the Live Cattle Futures contract at the Chicago Mercantile Exchange (CME) before and after the 1995 contract changes. Additionally, an alternative method of basis calculation utilizing weighted mean futures prices versus settlement futures prices was compared to determine which method provides a better representation of the basis level. Within a regression model with heteroskedascity error framework, we found that the level of nearby basis in the period after June 1995 has shifted lower and the average monthly open interest of net commercial long positions has substantially increased after the contract modifications. These empirical results are consistent with the notion that more long activity entered the market in response to the contract modifications. Additionally, an alternative (new) measure of basis calculation (cash price minus weighted mean futures price) produced similar results to two other commonly used measures. In conclusion, the 1995 contract changes have neither increased nor decreased the volatility of live cattle basis. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:557–590, 2004     

迷上酒吧的理由

有人比喻酒吧是水泥城市的天窗，“人们迫不及待地探出头，试图逃脱逼仄的空间，哪怕得到片刻的欢娱。”而在成都，在迷上——一个酒吧，富有想象力的名字将欢娱变成了前戏：人们夜夜笙歌，长久缠绵悱恻。[编者按]     

青岛，爱上你的N个理由

一月,青岛收到了2006年的第一份快乐和喜悦。在全国主流网络媒体新浪网的网络评选中,青岛,以绝对性的优势赢得广大网民心目中的“2005年度中国最具风情城市”。非官方的评比,没有专家团参与论证,甚至,没有严格的评选标准明细…… 100多万网民投票评选,足以证明它的分量。不靠宣传、不靠造势、不靠吹捧,一个城市用它的魅力感染着越来越多的人。不能不说这是一个城市最好的成绩单。青岛,有着让人们深深爱恋的N个理由。     

循环经济的投入产出分析

本文运用投入产出理论对循环经济进行了量化分析，首先，在模型中将循环经济部门从生产部门和消除污染部门中分离开来，在投入不变的条件下，运用循环经济下的各种经济指标来研究新的投入产出关系。其次，通过比较研究的方法，来分析循环经济对整个国民经济的影响程度及对其效果进行评价。最后本文还探讨了在不引入循环生产部门的情况时循环经济的投入产出关系。     

Balance Sheet Restructuring and Investment

Abstract
This article looks at the evolution of corporate balance sheets and investment over the past few years .
We find that many companies have significantly improved their balance sheets in this time. Leverage has been reduced, and this, coupled with lower nominal interest rates, has improved the interest cover and cash flows of the corporate sector. For many firms, the process of balance sheet repair has proceeded a long way so that the extent to which the financial position of firms will impinge on investment is much lower than it was a few years ago.
Looking further ahead, it appears that the rate of return to investing in capital is relatively high, at least when judged against the standards of earlier downturns. With the recovery picking up pace we should, therefore, see firms more inclined to expand their capital expenditure and less focused on financial restructuring.     

A rational foundation for wishful exchange rate forecasts

Professor Takatoshi Ito in a recent American Economic Review paper documents that exporters and importers have biased exchange rate forecasts and the biases are in opposite directions. At first glance, it is difficult to provide a rational foundation for such behavior. Professor Ito hypothesizes that these forecasts are the result of wishful expectations. However, if forecasts are stochastic, then minimization of a quadratic loss function results in a rational hedge applied to either $/¥ or ¥/$. The different perspectives of importers and exporters determines which form is hedged and determines the direction of the bias.