Derivation and application of unit cost expressions perturbed by design changes

Learning curves have been used extensively to predict future costs in the airframe and other industries. This paper deals with the effect of perturbations induced by design changes on the learning curves. Equations that are developed and applied make it possible to predict future costs accurately in a perturbed environment. The formulations can be used effectively in EDP programs.     

一个新的组合恒等式及其证明

本文以定理的形式提出一个新的组合恒等式。它是在恒虚警算法研究和性能分析中经常遇到的恒等式。对此,文中给出详细的证明。在证明过程中,我们还提出了有关该定理在实际中可以直接应用的3个引理和2个推论。     

旋转稳定塑料弹体工程设计计算研究

本文以实验结果为依据,首先分析了塑料弹体影响弹丸膛内运动的物理性能,然后结合旋转弹丸的膛内运动特征,经过模拟试验,采用数学拟合法,初步建立旋转稳定弹塑料弹体工程设计计算的数学模型(包括结构尺寸设计计算、强度计算和内弹道计算)。     

‘Winston has gone mad’: Churchill,the British Admiralty,and the Rise of Japanese Naval Power

As Chancellor of the Exchequer during the late 1920s, Winston Churchill was at the center of British strategic decision making about how to respond to the naval challenge posed by Japan's rise as a rival sea power. Churchill downplayed the likelihood of war with Japan. The leadership of the Royal Navy disagreed: they saw Japan as a dangerous threat to the security of the British Empire. Examining this dispute between Churchill and the Admiralty highlights the awkward political, economic, and strategic tradeoffs confronting British leaders between the world wars.     

Troubled triangle: Russia,Ukraine and the United States

A potentially productive triangular arrangement among Russia, Ukraine, and the United States emerged in 1994 from efforts to constrain nuclear weapons diffusion. By 2001, this promising initiative was nearly moribund, owing to the inability or unwillingness of the parties to fulfill the commitments of subsequent agreements. The domestic and external causes of this failure are many and clear. Yet the advantages to each of reengaging in a trilateral relationship are also plain. This means fulfilling their unfinished agenda by learning from past mistakes, adopting realistic premises and goals, and pursuing ‘bottom up’ as well as ‘top down’ strategies.     

Robust shortest path problems with two uncertain multiplicative cost coefficients

We consider a robust shortest path problem when the cost coefficient is the product of two uncertain factors. We first show that the robust problem can be solved in polynomial time by a dual‐variable enumeration with shortest path problems as subproblems. We also propose a path enumeration approach using a K ‐shortest paths finding algorithm that may be efficient in many real cases. An application in hazardous materials transportation is discussed, and the solution methods are illustrated by numerical examples. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013