The effects of local elections on national military spending: A cross-country study

In this paper, we study the domestic political determinants of military spending. Our conceptual framework suggests that power distribution over local and central governments influences the government provision of national public goods, in our context, military expenditure. Drawing on a large cross-country panel, we demonstrate that having local elections will decrease a country’s military expenditure markedly, controlling for other political and economic variables. According to our preferred estimates, a country’s military expenditure is on average 20% lower if its state government officials are locally elected, which is consistent with our theoretical prediction.     

Comparison of rank aggregation methods based on inherent ability

Ranking is a common task for selecting and evaluating alternatives. In the past few decades, combining rankings results from various sources into a consensus ranking has become an increasingly active research topic. In this study, we focus on the evaluation of rank aggregation methods. We first develop an experimental data generation method, which can provide ground truth ranking for alternatives based on their “inherent ability.” This experimental data generation method can generate the required individual synthetic rankings with adjustable accuracy and length. We propose characterizing the effectiveness of rank aggregation methods by calculating the Kendall tau distance between the aggregated ranking and the ground truth ranking. We then compare four classical rank aggregation methods and present some useful findings on the relative performances of the four methods. The results reveal that both the accuracy and length of individual rankings have a remarkable effect on the comparison results between rank aggregation methods. Our methods and results may be helpful to both researchers and decision‐makers.     

单层平板吸波体界面反射模型的带宽理论研究

为了优化和指导吸波体设计,介绍了单层平板吸波体界面反射模型,推导了模型所揭示的吸波体内部能量流动关系。在此基础上,导出吸波体反射吸收带宽计算公式,由界面反射模型得出影响吸收带宽的因素,包括吸波层厚度、1/4波长厚度在峰值频率处的变化率、指定的反射波能量、前界面反射波能量及后界面反射波能量等。利用推导的能量关系及带宽公式,对3个同轴样品进行分析计算,结果表明计算值与实验值吻合较好,带宽公式推导正确。     

微波暗室静区反射率电平的能量法仿真

为提高微波暗室静区反射率电平在低频段的仿真计算精度,基于惠更斯原理和余弦辐射体的辐射通量计算公式,推导静区内某一点的直接辐射功率和来自室内6个面的间接辐射功率公式。在此基础上,得到微波暗室静区反射率电平能量法仿真计算模型。最后利用Matlab软件编程,对一个小型手机天线测试用微波暗室静区3个截面上的反射率电平进行能量法仿真计算。结果表明,能量法仿真得到的结果相比几何光学法更符合实际电磁波空间连续分布的特点。     

模型乳化油废水的稳定性研究

以模型乳化油废水从静置开始至实现油水分离所需静置时间Ts的大小作为表征模型乳化油废水稳定性的标准,研究了粒径分布、表面活性剂类型、表面活性剂质量浓度和油分质量浓度对模型乳化油废水稳定性的影响规律。结果表明:其他参数相同时,模型乳化油废水的稳定性随平均粒径D(3,2)的增大而降低,随油分质量浓度的增大而增加;以阳离子表面活性剂C16H3(3CH3)3NBr、非离子表面活性剂C64H124O26和阴离子表面活性剂C18H29SO3Na为乳化剂的3种模型乳化油废水稳定性依次递增;当表面活性剂质量浓度处于较小范围内,模型乳化油废水的稳定性随表面活性剂质量浓度的增大而增加,但当表面活性剂质量浓度过大,超过临界胶束浓度,模型乳化油废水的稳定性反而降低。     

纵火战斗部爆炸分散仿真研究

在试验的基础上,从炸药对纵火炬的驱动和纵火炬在空中飞散两个方面,对其在战斗部静爆和动态飞行时的爆炸分散进行了仿真研究,研究结果对纵火弹的具体设计具有重要的参考价值。     

数列最优成组剖分的一个动态算法

数学工作者从铁道调车问题,抽象出一个数学问题,称为数列的成组剖分问题。本文给出一个递推公式,利用递推公式可以逐步减少数列中数值的个数,从而得到求数列最优成组剖分数的一个动态算法。     

应用四元数理论确定头盔瞄准系统的瞄准线

讨论了头盔瞄准具电磁敏感系统的工作原理,研究了确定头盔瞄准系统瞄准线的两种方法,结合工程实践建立了四元数法确定瞄准线的数学模型,给出了计算结果,并进行了结果分析。     

科研选题重复因素的分析与对策初探

科研选题中,周期短、见效快的课题重复率较高,其原因与科技人员晋级需求,社会集团易对“短、平、快”选题投资,科研管理人员的情报意识淡漠等因素有关。改变现状需要科技政策的制定者对基础科学研究和从事基础科学研究的人员给予更多的重视和政策的倾斜。科研管理部门应把握科研方向、人才培养、选题调整及发挥专家对审题的充分论证。采取各项综合措施,可望降低科研选题的重复。     

实用的滤波新算法

介绍了武器系统作战软件的一种计算量小、计算效果好的滤波新算法,并对该算法进行了对比分析