基于K均值排序方法的频域盲分离算法

针对频域盲分离算法中存在的排序不确定性问题,提出一种基于K-means算法的排序方法。该方法在排序中使用K-means算法对分离子信号进行整体排序,与传统相邻频点排序方法相比,大大提高了盲源分离的鲁棒性。仿真结果表明了该方法的有效性。     

边界元-有限差分混合方法在气垫船破冰数值模拟中的应用

对气垫船破冰作业的几种工况建立了统一的数学模型,提出了采用边界元法与有限差分法相结合的数值计算方法。采用C语言编制数值模拟程序,对气垫船兴波阻力、水面和冰面波形以及冰层内应力进行计算,通过调用Intel MKL数学库求解离散得到线性代数方程组;在C语言中调用Matlab计算引擎实现了计算网格和部分计算结果的显示;在多核计算机上采用OPENMP实现程序关键部分的并行计算,提高了计算速度。气垫船在全冰面上兴波阻力的计算结果与已有文献的理论分析计算结果和试验结果符合较好。     

The Nuclear Peace Fallacy: How Deterrence Can Fail

Some scholars counter-intuitively argue that the proliferation of nuclear weapons increases international security by substantially reducing the chances for inter-state armed conflict. This school of thought draws heavily on the history of the American-Soviet Cold War rivalry to inform its analysis. The security dilemmas in the contemporary Middle East and South Asia where numerous states have or want nuclear weapons, however, are profoundly different than the competition between the United States and the Soviet Union. States in the Middle East and South Asia today may see nuclear weapons as usable instruments of warfare in contrast to conventional wisdom in the West that views them as weapons of deterrence and last resort. As common sense would have it, American and Allied policy designed to stem the proliferation of nuclear weapons is prudent. American diplomatic intervention, moreover, in regional crises as a third party may be needed in the future in the Middle East and South Asia to lessen the risks of nuclear warfare. Nevertheless, American policy-makers are likely in the future to find themselves facing a nuclear-armed nation-state-or soon to be nuclear weapons-capable state-in a crisis and will have to grapple with the risks of pre-emptive or preventive military action.     

An analytical evaluation of optimal solution value estimation procedures

The estimation of optimal solution values for large-scale optimization problems is studied. Optimal solution value estimators provide information about the deviation between the optimal solution and the heuristic solution. Some estimation techniques combine heuristic solutions with randomly generated solutions. In particular, we examine a class of jacknife-based estimators which incorporate any heuristic solution value with the two best randomly generated solution values. The primary contribution of this article is that we provide a framework to analytically evaluate a class of optimal solution value estimators. We present closed-form results on the relationship of heuristic performance, sample size, and the estimation errors for the case where the feasible solutions are uniformly distributed. In addition, we show how to compute the estimation errors for distributions other than uniform given a specific sample size. We use a triangular and an exponential distribution as examples of other distributions. A second major contribution of this article is that, to a large extent, our analytical results confirm previous computational results. In particular, the best estimator depends on how good the heuristic is, but seems to be independent of the underlying distribution of solution values. Furthermore, there is essentially an inverse relationship between the heuristic performance and the performance of any estimator. © 1994 John Wiley & Sons, Inc.     

舰空导弹测试项目优化方法研究

舰空导弹测试项目设计优化的目标应是全面但最简。提出如下优化方法:用Luenberger状态观测器法提取能覆盖各方面性能的测试项目最简集合,根据可靠性预计、故障分析得到的可靠性薄弱环节筛选,最后根据各类测试的不同需求和约束条件确定测试项目集合。其思路和方法也可用于其他复杂系统。     

倾斜地面上软体油罐储油形态数值分析

软体油罐罐体与罐内液体的相互作用为典型的流构耦合问题。采用有限元分析软件LS—DYNA,首先通过控制体积法得到了软体油罐充液后的有限元模型,然后采用任意拉格朗日欧拉算法分析了地面倾斜时软体油罐的形态表现,研究了储液体积恒定时,地面倾角与储液高度的关系。提出了倾斜地面上软体油罐体积计算的修正公式,模拟情况和实际情况比较接近,为软质储液容器的测量及误差修正提供了重要的参考依据。     

综合火控系统对地轰炸精度分析仿真

针对航空轰炸武器火控系统精度分析问题,分别建立了数值微分算法和蒙特卡洛算法模型,并开发了仿真分析软件.给出了两种模型的推导过程,以及微分步长的优化方法.利用本算法软件对某型火控系统进行精度分析仿真,并对多组典型投弹条件的仿真结果进行分析.结果表明,两种算法优势互补,能有效地对火控系统进行精度分析,对改进系统设计、提高系...     

陆空火力协同仿真推演验证系统设计

针对陆空联合作战中火力协同方案制订、验证手段方法的不足,采用计算机仿真的方法,从安全防误伤的角度对陆空火力协同方案进行了仿真推演评估。分析了功能需求和体系结构,建立了武器装备运动轨迹模型和陆空火力协同安全性判别模型,研究了仿真时钟推进机制和提高仿真速度的方法,设计了陆空火力协同仿真推演验证系统。作战演习应用表明：该系统仿真推演验证快速、准确、便捷、有效。     

核心维修能力的概念分析

从美军核心维修能力的定义着手,对我军核心维修能力进行定义与分析,深入阐述了核心竞争力、基地级核心维修能力等4个核心维修能力的相关概念,将核心维修能力的主要属性归纳为必需性、完整性、层次性、动态性,并对各个属性进行分析,对我军核心维修能力的确定以及建设具有重要意义。     

重型装备回收系统气囊缓冲特性研究

将气囊缓冲过程分解为绝热压缩和排气释能2个过程,从热力学和运动学方程出发,建立考虑降落伞阻力影响的缓冲气囊的解析分析模型。基于该模型,对立式气囊的缓冲特性进行研究。结果表明：降落伞阻力对缓冲性能有微小影响,在计算中可以忽略。在理论分析的基础上给出了系统质量与气囊初始体积比的最优值,探讨了排气口固定型与可控型气囊的缓冲特性及其应用优劣。