奇异积分方程在裂纹板条动态断裂分析中的应用(II)

采用Ｄｕｒｂｉｎ反演法,将Ｌａｐｌａｃｅ变换域中的动态应力强度因子转换为时域中的解。给出了数值算例,证实了本文方法的合理性。通过对计算结果的分析,得出了一系列有趣而有意义的结论     

一种用于声目标识别的小波变换去噪方法

根据受噪声污染信号的小波变换系数中对信号有贡献的仅占其很小一部分的事实,提出了一种基于系数门限值去噪的方法。对不同信号的仿真结果表明该方法去噪效果明显,运算量小,适合用于对声目标识别系统的噪声去除。这对于改善声目标识别系统的抗噪性能是十分有意义的。     

FFT的8088汇编语言程序实现

本文针对使用8088汇编语言实现基2FFT 的难点,就旋转因子的求取、比例系数的选择、16位乘积的获得以及运算溢出等问题提出了有效的解决方法,并给出了具体程序.从而,可使 FFT 运算速度较单纯运行相应的高级语言程序提高20倍左右.     

子波域中图象数据的矢量量化

介绍了子波变换的基本理论及特点,并用它对图象进行三层分解。矢量量化优于标量量化。它已成功地应用于图象的数据压缩。文中应用失显量化法量化图象于波域数据,取得较满意的压缩效果。     

一种基于小波变换的红外图像对比度增强技术

将小波变换理论应用于红外图像处理 ,提出一种基于小波变换的红外图像对比度增强方法。对低对比度的红外图像施行小波变换 ,得到其多尺度梯度分布 ;合理地增强其在各个尺度上的梯度模值 ,直接扩大尺度空间图像的动态范围 ,既增强了图像的对比度 ,又控制了噪声。实验结果表明 ,与直方图均衡方法相比 ,此方法效果较佳     

Measuring the Impact of Military Spending: How Far Does a DSGE Model Deviate from Reality?

Dunne, Smith, and Willenbockel (2005) argue that the mainstream growth literature has not found military spending to be a significant determinant of economic growth, yet much of the defense economics literature has noted significant effects. This paper revisits this issue by using a DSGE-VAR approach, combining both theoretical and empirical methods. We present that the DSGE approach (estimated with the Bayesian technique) and the Bayesian VAR with the Minnesota Prior both lead to worse in-sample fit than our proposed DSGE-VAR framework. The DSGE-VAR approach reveals that a positive military spending shock boosts the U.S. economy, increasing per capita real GDP growth, consumption, inflation and interest rate. Our results are robust to alternative model specifications. Future investigations such as exploring an optimal military spending policy could adopt the approach in this paper to determine the best model – empirical, theoretical, or a combination of the two.     

Dangerous work: Terrorism against U.S. diplomats

The goal of diplomats is to represent their countries’ interests through diplomacy, not arms. Because they are not military personnel, they may be perceived as at lower risk of being the target of terrorists. However, recent events have called this perception into question. Despite this danger, there has been little research on terrorist attacks against diplomats. Drawing on the terrorism studies literature, this article argues that diplomats are targeted more than non-diplomatic targets in countries where certain U.S. foreign policies are implemented. An empirical analysis of 471 attacks against U.S. diplomats from 1970 to 2011 reveals that while U.S. alliances and foreign aid increase the likelihood of attacks against diplomats, U.S. military intervention and civil war, on the other hand, increase the risk of terrorism against non-diplomatic targets. This finding is relevant because it shows terrorist attacks against diplomats result from certain types of foreign policy.     

The nuclear education of Donald J. Trump

During the 2016 American presidential campaign, Democrats and Republicans alike repeatedly raised concerns at the prospect of Donald Trump being in charge of America’s nuclear arsenal based on his seemingly unstable personality. Unfortunately, this emphasis on Trump’s character distracted attention from any in-depth investigation into his long-standing interest in nuclear issues. This article seeks to remedy this shortcoming by highlighting the nuclear legacy Trump will inherit from Obama, surveying his statements on nuclear issues over more than three decades, and providing an analysis of constraining factors on his administration’s nuclear agenda, particularly domestic institutions. It finds that most of Trump’s views on nuclear issues are relatively consistent with past Republican presidents. Where he is unique, however, is in his use of social media, which has potential implications on nuclear signaling.     

基于BPAF判决的决策层目标属性融合研究

在D-S证据理论框架下,研究了基于目标基本概率赋值(BPAF)判决的决策层目标属性融合问题。简要介绍了D-S证据组合理论框架,阐述了基于BPAF判决的决策层目标属性融合策略、步骤;分析了证据严重冲突时,Dempster证据组合规则不合理的本质原因;提出必须对D-S证据组合规则进行改善等需要继续深入探讨的几个问题。     

基于小波包变换和伪魏格纳分布的轴承故障诊断

将小波包变换理论和伪魏格纳分布应用于齿轮箱故障诊断中,结合实例对轴承的振动信号进行分析,结果表明:小波包变换能有效地提取各频段的高频成分,通过对提取的信号做伪魏格纳分布,结果能形象、直观地反映出轴承故障的时-频信息,而且对故障信息具有较强的判别能力。