求解卷积公式的一种新方法

基于数形结合方法以及变量代换方法发现计算卷积公式存在某些不足之处,研究卷积公式的计算方法,给出一种新的确定积分限的方法.该方法直观明了、容易理解和掌握并且可操作性强,有效避免作图和分析图形的繁琐,并举例说明了该应用方法.     

ANALYSING QUITS AND SEPARATIONS FROM THE ROYAL NAVY

Manning difficulties and retention of skilled personnel is a timely issue in the British armed forces, and especially in the all‐volunteer Royal Navy. Allied with difficulties of matching personnel numbers and posts, significant skill mismatches can take a long time to eradicate, with obvious financial and operational penalties. In the light of these factors, a holistic understanding of the exit behaviour of naval personnel is vital for naval manpower planners. This paper analyses ratings’ voluntary (quits) and involuntary (separation) exit patterns from the Royal Navy using an independent competing risks hazard regression analysis framework. The results show that both voluntary and involuntary exits are pro cyclical with respect to macroeconomic and labour market conditions for both male and female ratings. Male ratings are more likely to quit or separate due to a lack of promotion to higher ranks as compared with females. Male ratings are also more likely to quit as a result of a hectic operational tempo when compared with their female counterparts. Frequency of sea/shore deployments also seems to exert a significant effect with respect to quits and separation outcomes of both genders. In terms of marital status married males are less likely to quit compared with their unmarried male counterparts, whereas the opposite is the case for female ratings.     

A note on the financial condition of defense contractors

In recent years, there have been several changes in the weapon‐system acquisition market which have the potential to negatively impact the financial condition of defense contractors. This study evaluates the financial health of defense firms vis‐a‐vis nondefense firms using a fiscal distress identification model developed by E.I. Altman. We conclude that the financial condition of defense firms has deteriorated but the deterioration is the same as experienced by nondefense firms.     

Alternative models of Greek defence expenditures

This paper models and estimates Greek defence spending over the 1950–1989 period. It employs the Stone‐Geary welfare function and estimates levels of defence expenditures by the Engle‐Granger two‐step procedure. The Dickey‐Fuller test regression for cointegration is specified in terms of the significance of additional augmentations. The Deaton‐Muellbauer functional form is then employed and an estimating equation for the expenditure share of defence is derived. This specification is compared with the levels equation through a number of non‐nested tests involving model transformation.     

TERRORISM: FACTS FROM FIGURES 1

If international terrorism is on a rising trend, an important source of confirmation or refutation of this is time‐series data on terrorist activity. Using chiefly data collected by the RAND/MIPT consortium we show using basic statistical analysis that in the period 1968–2005 the yearly number of all international terrorist incidents shows no trend over time, but fluctuates year on year in a random manner. On the other hand some indicators do show a definite trend over time, principally the steady rise in the number of incidents that are death‐dealing in nature. A further conclusion is drawn, showing that the proportion of these incidents leading to deaths above a given level is virtually fixed.     

Resourcing for defense: Solving the roles and missions puzzle

One of the most important issues facing the post‐Cold War U.S. defense establishment concerns the future allocation of combat tasks and responsibilities among different branches of the armed forces. The challenge is to reduce unnecessary redundancy across roles and missions when resources are highly constrained, without compromising military effectiveness. Defining the policy problem as one of resource allocation rather than operational effectiveness, we develop a methodology for allocating roles and missions. Our methodology focuses at the highest level of force aggregation and uses a mathematical programming model to produce cross‐service cross‐mission trade‐offs that will yield the best total force combat and non‐combat potential within resource consumption constraints.     

基于DPA的LED非线性部件逆向研究

在军事和商业应用中有很多密码算法是半公开或者不公开的,旨在证明算法保密对密码的安全性提高并没有明显帮助．针对轻型分组密码LED的未知非线性部件S盒,提出了一种基于差分功耗分析的逆向方法,该方法可以利用差分功耗曲线的极性信息来恢复未知算法结构．实验结果表明,在LED的S盒参数未知时,利用功耗采集平台采集算法运行时泄露的旁路功耗信息,可以成功逆向出全部s盒信息,验证了该方法的可行性．     

计数序贯抽样检验方案的OC函数和ASN

根据序贯概率比检验的理论,给出计数序贯抽样检验方案的设计原理,得到国家标准GB／T8051—2008中计数序贯抽样检验方案的OC函数和ASN的计算方法。     

火炮抽筒故障机理研究

针对某自行反坦克炮射击后,抽筒时出现药筒钢底座底缘与圆柱部断裂现象这一抽筒故障,分析计算该火炮正常抽筒所需的理论抽筒力和半自动开闩机构所能提供的实际抽筒力,由此定量分析该故障的主要原因,并提出火炮实弹射击预防抽筒故障的具体措施,对半自动开闩结构设计与改进、部队装备训练与射击具有一定指导和参考价值．     

弹药洞库有害气体分布规律研究

以计算流体力学（CFD）为理论基础,应用GAMBIT软件对洞库内的有害气体进行几何模型构建和网络划分,用FLUENT软件对所建模型中有害气体的扩散和分布规律进行模拟分析,并对单一释放源条件下扩散规律进行比较,分析弹药堆垛对气体扩散的影响．通过对洞库内有害气体的整体分布规律的研究,找到了库房内有害气体浓度最高的位置．最后,通过实验对仿真结果进行验证．