C/SiC复合材料残余应力的电火花小孔法测定研究

进行了C/SiC复合材料残余应力的小孔法表征.基于现有小孔法的不足以及材料的较好电导率,提出了电火花打孔法的残余应力测量方法,建立了相应的残余应力测量流程.进行了不同平整表面样品的残余应力测量.结果表明电火花打孔法具有较好的区分性,也表明C/SiC复合材料具有较小的本征残余应力和机加工应力,这说明:C/SiC复合材料作为反射镜材料具有很好的面形稳定性的优势.     

军用多波段数字接收机研究

本文结合软件无线电设计思想 ,研究了一种HF/VHF数字接收机 ;并从系统的角度 ,分析了各关键部件的设计 ,特别是SSB(单边带 )波形和FM (调频 )波形的数字化解调。最后给出了系统实现的硬件平台。     

Exact analysis of (R,s, S) inventory control systems with lost sales and zero lead time

We study an (R, s, S) inventory control policy with stochastic demand, lost sales, zero lead‐time and a target service level to be satisfied. The system is modeled as a discrete time Markov chain for which we present a novel approach to derive exact closed‐form solutions for the limiting distribution of the on‐hand inventory level at the end of a review period, given the reorder level (s) and order‐up‐to level (S). We then establish a relationship between the limiting distributions for adjacent values of the reorder point that is used in an efficient recursive algorithm to determine the optimal parameter values of the (R, s, S) replenishment policy. The algorithm is easy to implement and entails less effort than solving the steady‐state equations for the corresponding Markov model. Point‐of‐use hospital inventory systems share the essential characteristics of the inventory system we model, and a case study using real data from such a system shows that with our approach, optimal policies with significant savings in inventory management effort are easily obtained for a large family of items.     

谈MIS系统的体系结构

体系结构是计算机系统及其组件的物理构造或设计方案 ,文章探讨了 3种典型的体系结构在MIS系统中的应用。     

基于MVC的分布式作战应用框架研究

MVC作为一种经典的软件模式,在界面程序设计和B/S系统中得到了广泛应用.随着分布式技术的发展,MVC的含义和用途变得更加广泛,不仅可以用于组件的构造,也可用于分布式程序的设计.针对MVC模式和分布式作战应用的特点进行了深入分析,提出了一种基于MVC的分布式作战应用框架,在保持传统C/S架构优势的同时,增强了系统的可扩展性,实现了业务流程和逻辑计算的有效分离,为大型C/S作战应用系统的开发提供了一个有效的架构解决方案.     

一种发送速率精确可控的分布式网络流量生成方法

介绍了一种灵活高效的分布式网络流量生成方法；通过加入权重因子，利用反馈机制不断对产生的网络流量进行调整直至流量大小误差符合用户设定需求；结合ON／OFF模型，采用分布式结构产生了流量速率可调节的具有自相似特性的网络流量。通过该方法产生的网络流量大小精确可控，且具有自相似性，能更好地反映出真实网络流量的特性。     

The ballot or the bomb belt: the roots of female suicide terrorism before and after 9/11

ABSTRACT

In recent years, an upward trend in terrorist attacks has mirrored an increase in suicide attacks. According to our preliminary analysis, the events of September 11^th marked a sea change in the number of terrorist attacks. While a rich literature has evaluated why terrorists participate in suicide attacks, none have considered the uptick in volume after 9/11, and fewer yet have considered how female fighters may be contributing to this. We evaluate how both structural and female-specific factors affect the likelihood of female fighter suicide attacks. Recent literature discovered a trend in terrorist groups using females as suicide bombers due to cultural norms that permit them to get closer to targets. We test our theory using data from the Chicago Project on Security and Threats Suicide Attack Database (CPOST-SAD) and various datasets from the Quality of Government (QOG) compendium for the 1986–2016 time period. We construct a series of models that consider both female-specific and structural factors that could explain variation in the number of female suicide attacks. Our results indicate that our models encompass relatively stable patterns. Female political empowerment, female educational attainment, and female employment rates are significant and positive in our post-9/11 models, indicating that they may increase female suicide attacks. Democracy is a relevant structural factor and generally yields a positive effect on female suicide attacks across both time periods and multiple models. Ethnic fractionalization is significant in both time periods but yields a negative effect before 9/11 and a positive effect in the later period.     

液氧甲烷膨胀循环变推力发动机系统方案对比研究

当前对液氧甲烷膨胀循环变推力火箭发动机的研制难点和关键技术认识不够清楚,尤其是在大变比推力调节方案方面。基于整个发动机系统,采用理论计算方法,探讨甲烷膨胀做功能力以及变推力调节方案可行性。分别给出了单涡轮系统方案和双涡轮系统方案,首次给出了不同工况下详细的系统状态参数分布,进行了对比分析,并探讨了甲烷做功能力随室压的变化规律。研究结果表明,甲烷做功能力随着室压的减小呈现先减小后增大的趋势,单涡轮和双涡轮系统方案均能够实现大范围推力调节;相比单涡轮方案,双涡轮方案能够更好地保证混合比,且甲烷气体做功能力利用效率更高,氧涡轮和燃料涡轮功率变化范围较窄,涡轮所处环境较为缓和,因此双涡轮系统方案具备一定优势。     

机载电子设备I/O装置测试系统设计

为了在复杂环境下对某飞机的机载电子设备进行功能测试和故障定位,提出了一种基于PXI总线技术的测试系统,可以在各种环境下实现整机联合测试,也可实现该机载电子设备场外可更换组件的单件测试,实现的I/O单件测试.新的测试系统对原有检测平台进行了合理的借鉴,使得检测程序化、系统化、智能化.     

坦克嵌入式车场射击训练炮长操纵控制模型

在嵌入式射击模拟训练系统中,针对炮长操作过程对模拟训练的影响,建立了炮长操纵控制模型。炮长操纵控制模型包括炮长操纵模型和炮长射击决策模型。炮长操纵模型的建立是基于装备的物理模型和人的生理反应模型。炮长射击决策模型根据坦克射击教范要求,采用与/或正向演绎推理得到。在炮长操纵控制模型基础上,建立了射击反应时间模型,并与实际装备操作进行了比较,对建立的操纵控制模型进行了验证。