火控雷达的仿真目标建模及实现

中外军队的实践证明 :模拟训练是一种最简便、成本低、效果好的训练方式。对于需要空情保障和训练成本高的雷达训练来说更是如此。探讨了火控雷达回波信号的模型建立及实施方案。     

一种双参数批更换系统的优化问题

研究了一种在更换时间有限的情况下 ,基于交替更新过程的双参数批更换系统的优化问题 ,这一问题的目标是平均费用率的极小化。给出了一种特殊情况的讨论结果。     

双连杆机构发动机运动学分析

对双连杆机构的运动学进行了理论分析,推导出了活塞的位移、速度和加速度公式及活塞侧连杆和曲轴侧连杆摆角公式,并且针对一实例进行了计算,与相同结构尺寸的传统曲柄连杆机构发动机作了比较分析.     

飞行器低空突防威胁建模与航迹优化算法

提出了一种飞行器在给定地形和威胁分布的威胁场进行低空突防的航迹优化算法。该方法首先对地形的高程栅格数据进行了图形简化预处理,将各种威胁叠加到地形图上,构成一个包含各种威胁的特定威胁场,再对其建立合理的有向图数学建模,用Dijkstra最短路算法进行航迹优化。航迹优化的过程中考虑了飞行器的过载限制,使优化航迹能够较好地满足飞行器各项性能指标及任务规划的要求,仿真结果显示,该算法简单快速,能很好地进行地形、威胁、障碍物的回避。     

根据输入噪声估算通信距离

提出并论证了一种根据输入噪声估算战术电台通信距离的方法,并且以VRC-8000电台在城郊通信为例进行了具体的分析计算.该方法对于实现战术电台迅速、可靠地通信有实际意义.本文进而提出了检测电台收信机输入噪声的技术方案,供选用.     

Preparation and property of CL-20/BAMO-THF energetic nanocomposites

A sol-gel freezing-drying method was utilized to prepare energetic nanocomposites based on 2, 4, 6, 8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane (CL-20) with 3, 3-Bis (azidomethyl) oxetane-tetrahydrofuran copolymer (BAMO-THF) as energetic gel matrix. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, Fourier-transform infrared spectroscopy (FT-IR) and differential thermal analyser (DTA) were utilized to characterize the structure and property of the resultant energetic nanocomposites. Compared with raw CL-20, the average particle sizes of CL-20 in CL-20/BAMO-THF energetic nanocomposites were decreased to nano scale and the morphologies of CL-20 were also changed from prismatic to spherical. FT-IR detection revealed that CL-20 particles were recrystallized in BAMO-THF gel matrix during the freezing-drying process. The thermal decomposition behaviors of the energetic nanocomposites were investigated as well. The thermolysis process of CL-20/BAMO-THF nanocomposites was enhanced and the activation energy was lower compared with that of raw CL-20, indicating that CL-20/BAMO-THF nanocomposites showed high thermolysis activity. The impact sensitivity tests indicated that CL-20/BAMO-THF energetic nanocomposites presented low sensitivity performance.     

双六边形环电路模拟吸波材料及其等效电路模型

提出以双六边形环为单元结构的电路模拟吸波材料。根据单元的双频特性建立等效电路模型,根据六边形环周期分布规律提出等效周期概念,给出等效分布电参数的计算方法。利用该模型对双六边形环电路模拟吸波材料的结构进行参数分析,并与HFSS全波分析结果进行对比,验证该方法的准确性。加工样品和实测,结果发现所设计吸波材料在1.9~8.9 GHz频段内对正入射波具有良好的吸波特性,实测结果与等效电路模型仿真结果吻合较好,进一步验证了该方法的有效性。     

A worst‐case formulation for constrained ranking and selection with input uncertainty

In this research, we consider robust simulation optimization with stochastic constraints. In particular, we focus on the ranking and selection problem in which the computing time is sufficient to evaluate all the designs (solutions) under consideration. Given a fixed simulation budget, we aim at maximizing the probability of correct selection (PCS) for the best feasible design, where the objective and constraint measures are assessed by their worst‐case performances. To simplify the complexity of PCS, we develop an approximated probability measure and derive the asymptotic optimality condition (optimality condition as the simulation budget goes to infinity) of the resulting problem. A sequential selection procedure is then designed within the optimal computing budget allocation framework. The high efficiency of the proposed procedure is tested via a number of numerical examples. In addition, we provide some useful insights into the efficiency of a budget allocation procedure.     

On the conditional residual lifetime of coherent systems under double regularly checking

In this paper, we consider a coherent system with n independent and identically distributed components under the condition that the system is monitored at time instances t₁ and t₂ (t₁ < t₂). First, various mixture representations for reliability function of the conditional residual lifetime of the coherent system are derived under different scenarios at times t₁ and t₂ (t₁ < t₂). Several stochastic comparisons between two systems are also made based on the proposed conditional random variables. Then, we consider the conditional residual lifetime of the functioning components of the system given that j components have failed at time t₁ and the system has failed at time t₂. Some stochastic comparisons on the proposed conditional residual lifetimes are investigated. Several illustrative graphs and examples are also provided.     

BDS/INS紧组合三频动对动模糊度解算方法

针对伪距观测噪声较大导致动对动条件下三频整周模糊度解法(Three Carrier Ambiguity Resolution, TCAR)模糊度解算不可靠的问题,提出了一种BDS/INS紧组合三频动对动整周模糊度解算方法。通过紧组合系统输出的高精度位置坐标,估算出双差几何距离值,并用其分别代替无几何和几何模式下的双差伪距观测值,显著降低了伪距双差观测噪声水平,有效提高了三频整周模糊度解算成功率。仿真实验结果表明,BDS/INS紧组合输出的高精度位置坐标使得伪距观测精度提高了60%以上,在短基线条件下,当伪距观测噪声达到2 m时,无几何模式下的TCAR算法模糊度解算成功率为0.73%,几何模式下的TCAR算法模糊度解算成功率为31.25%,而BDS/INS紧组合的TCAR算法在两种模式下的模糊度解算成功率达到99%以上,并且获得了厘米级的相对定位精度。