基于多Agent的战场情报侦察仿真模型

为了开展未来信息化战场情报侦察先期概念技术演示,通过采用基于多Agent的仿真方法,把情报侦察系统的内部组元直接映射成相应的Agent,研究了基于多Agent的战场情报侦察仿真系统总体框架和仿真系统基本单元Agent的框架;并进一步研究了Agent之间的任务分解、信息交换、选择与排序、分配过程。构建的仿真模型,以Agent的表现形式获得了对战场情报侦察这一客观、复杂过程的深刻认识,从而可实现对这种动态作战环境行为的仿真。     

Research on the influences of confining pressure and strain rate on NEPE propellant: Experimental assessment and constitutive model

In order to study the influences of confining pressure and strain rate on the mechanical properties of the Nitrate Ester Plasticized Polyether (NEPE) propellant, uniaxial tensile tests were conducted using the self-made confining pressure system and material testing machine. The stress-strain responses of the NEPE propellant under different confining pressure conditions and strain rates were obtained and analyzed. The results show that confining pressure and strain rate have a remarkably influence on the mechanical responses of the NEPE propellant. As confining pressure increases (from 0 to 5.4 MPa), the maximum tensile stress and ultimate strain increase gradually. With the coupled effects of confining pressure and strain rate, the value of the maximum tensile stress and ultimate strain at 5.4 MPa and 0.0667 s⁻¹ is 2.03 times and 2.19 times of their values under 0 MPa and 0.00333 s⁻¹, respectively. Afterwards, the influence mechanism of confining pressure on the NEPE propellant was analyzed. Finally, based on the viscoelastic theory and continuous damage theory, a nonlinear constitutive model considering confining pressure and strain rate was developed. The damage was considered to be rate-dependent and pressure-dependent. The constitutive model was validated by comparing experimental data with predictions of the constitutive model. The whole maximum stress errors of the model predictions are lower than 4% and the corresponding strain errors are lower than 7%. The results show that confining pressure can suppress the damage initiation and evolution of the NEPE propellant and the nonlinear constitutive model can describe the mechanical responses of the NEPE propellant under various confining pressure conditions and strain rates. This research can lay a theoretical foundation for analyzing the structural integrity of propellant grain accurately under working pressure loading.     

Investigation on the process parameters of TIG-welded aluminum alloy through mechanical and microstructural characterization

Multi-pass TIG welding was conducted on plates (15×300×180 mm3) of aluminum alloy Al-5083 that usually serves as the component material in structural applications such as cryogenics and chemical processing industries. Porosity formation and solidification cracking are the most common defects when TIG welding Al-5083 alloy, which is sensitive to the welding heat input. In the experiment, the heat input was varied from 0.89 kJ/mm to 5 kJ/mm designed by the combination of welding torch travel speed and welding current. Tensile, micro-Vicker hardness and Charpy impact tests were executed to witness the impetus response of heat input on the mechanical properties of the joints. Radiographic inspection was performed to assess the joint's quality and welding defects. The results show that all the specimens displayed inferior mechanical properties as compared to the base alloy. It was established that porosity was progressively abridged by the increase of heat input. The results also clinched that the use of me-dium heat input (1-2 kJ/mm) offered the best mechanical properties by eradicating welding defects, in which only about 18.26% of strength was lost. The yield strength of all the welded specimens remained unaffected indicated no influence of heat input. Partially melted zone (PMZ) width also affected by heat input, which became widened with the increase of heat input. The grain size of PMZ was found to be coarser than the respective grain size in the fusion zone. Charpy impact testing revealed that the absorbed energy by low heat input specimen (welded at high speed) was greater than that of high heat input (welded at low speed) because of low porosity and the formation of equiaxed grains which induce better impact toughness. Cryogenic (-196 C) impact testing was also performed and the results corroborate that impact properties under the cryogenic environment revealed no appreciable change after welding at designated heat input. Finally, Macro and micro fractured surfaces of tensile and impact specimens were analyzed using Stereo and Scanning Electron Microscopy (SEM), which have supported the experimental findings.     

基于广义随机Petri网GSPN的系统安全性研究

针对基于广义随机Petri网GSPN的动态系统安全性建模与分析方法进行了系统研究。基于Petri网、GSPN模型的基本原理,提出了关键状态搜索算法,并进行了安全性仿真分析.将广义随机Petri网的扩展模型应用于安全性分析领域,丰富了动态系统安全性问题的研究手段。     

将军"斗胆直陈"与中央民主决策

实事求是是党的马克思主义思想路线的核心.这四个字说起来容易,做到却很难.它既受思想水平、认识能力的限制,同时又检验着一个人(特别是领导干部)的党性原则,所思所想所作所为是否真正出于公心.对中国革命作出了重大贡献的无产阶级革命家、军事家粟裕大将,堪称坚持实事求是的楷模.     

基于HLA的C^4ISRK作战运用仿真系统探讨

C4ISRK是实现未来信息化战场"网络中心战"概念的一组必要的装备系统.着眼于为C4ISRK系统作战运用项目先期概念技术演示提供仿真平台,提出了C4ISRK系统的概念模型,在此基础上重点研究了基于HLA的C4ISRK作战运用仿真系统的总体框架及其设计,为该仿真系统的建立和仿真实施提供了技术支持.     

低信噪比抖动红外点目标的检测

本文为解决低信噪比条件下抖动红外点目标的检测问题，提出了一种基于膨胀累加、检测前跟踪的检测算法。该算法运用膨胀累加方法能够消除抖动对多帧累加算法的不利影响，使目标能量仍然能够实现有效的积累，从而达到目标增强的目的。本文还采用了小波变换预处理方法，对图象中相关的１／ｆ噪声进行白化。模拟实验结果表明，该算法能够快速检测出信噪比为２抖动点目标。     

新型印刷平面对数周期天线

本文在分析现有的印刷平面对数周期天线结构的基础上，提出了一种新的印刷平面对数周期天线结构。该结构克服了原有结构存在的缺点，使天线的性能得到了改进。设计了工作在０．４～２ＧＨｚ的新型印刷平面对数周期天线。测出了整个频带内的驻波、增益和Ｅ、Ｈ面方向图。可以看出，该结构形式的印刷平面对数周期天线具有良好的宽带特性。     

MIMD上三层格式的窗口并行迭代方法

本文对一般的三层格式给出了在MIMD 机上实现的窗口并行迭代方法,给出了WBJ 格式,分析了三层格式的收敛性。文章的结论表明窗口并行迭代法的收敛性与窗口大小无关,窗口大小影响每台处理机的使用效率。     

MPSTD算法在波导分析中的应用

研究了多域伪谱时域(MPSTD)算法应用于波导问题分析时的激励源设置,并在此基础上,采用MPSTD算法计算了波导截止频率和典型三维波导结构的S参数,计算结果与HFSS或FDTD的计算结果做了比较,数值仿真表明,将MPSTD算法应用于波导问题的分析,可实现对波导问题的精确建模,具有较高的计算效率和计算精度,波导问题的MPSTD分析拓展了MPSTD算法的应用领域,为复杂波导问题的精确求解提供了一种思路。