效力准则的电子战干扰效果度量的研究

探讨了舰载电子战系统干扰效果的度量准则,分析了压制干扰对反舰导弹的单发命中概率的影响,从研究系统射击效力指标的角度出发,提出一种新的评定舰载电子战干扰效果的准则——效力准则。并通过算例得出典型情况下系统施放压制性干扰时机与反舰导弹单发命中概率之间的关系。     

A novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise,minimum mean square variance criterion and least mean square adaptive filter

Underwater acoustic signal processing is one of the research hotspots in underwater acoustics. Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing. Owing to the complexity of marine environment and the particularity of underwater acoustic channel, noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing. In order to solve the dilemma, we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), minimum mean square variance criterion (MMSVC) and least mean square adaptive filter (LMSAF). This noise reduction technique, named CEEMDAN-MMSVC-LMSAF, has three main advantages: (i) as an improved algorithm of empirical mode decomposition (EMD) and ensemble EMD (EEMD), CEEMDAN can better suppress mode mixing, and can avoid selecting the number of decomposition in variational mode decomposition (VMD); (ii) MMSVC can identify noisy intrinsic mode function (IMF), and can avoid selecting thresholds of different permutation entropies; (iii) for noise reduction of noisy IMFs, LMSAF overcomes the selection of decomposition number and basis function for wavelet noise reduction. Firstly, CEEMDAN decomposes the original signal into IMFs, which can be divided into noisy IMFs and real IMFs. Then, MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs. Finally, both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained. Compared with other noise reduction techniques, the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals, which has the better noise reduction effect and has practical application value. CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection, feature extraction, classification and recognition of underwater acoustic signals.     

软件测试中的路径划分技术

路径覆盖测试准则要优于其它已知的覆盖准则,但由于对一般的软件,路径数目太大,以至实际难以实现。路径划分是路径覆盖技术的一个折中方法。给定的程序Ｐ和给定模块的最大路径数目ｋ,按就近原则,现给出了一种划分Ｐ的算法,使得每个划分后的模块所包含的路径数目都少于等于ｋ。同时也给出了最佳划分的度量标准和最佳划分方法。     

侦察无人机作战效能评估准则研究*

在对有人驾驶飞机作战效能评估方法的分析研究基础上,提出了完整的侦察无人机作战效能评估指标体系。建立了作战效能的评估准则与数学模型,并对影响侦察效能的参数进行了分析。运用该方法对“全球鹰”和“捕食者”两种无人机的侦察效能指数进行了定量评估,结果验证了该评估准则的可用性。     

Asymmetric information and third-party intervention in civil wars

I study a two-period model of conflict with two combatants and a third party who is an ally of one of the combatants. The third party is fully informed about the type of her ally but not about the type of her ally’s enemy. In a signaling game, I find that if the third party is unable to give a sufficiently high assistance to her ally, then there exists a unique separating equilibrium in which the third party’s expected intervention causes her ally’s enemy to exert more effort than in the absence of third-party intervention; this worsens the conflict.     

旋转弹控制系统结构与弹体静稳定特性研究

采用劳斯稳定判别法,结合某旋转弹的实际控制结构和弹体特性,对不同控制结构对静稳定度适应程度进行了分析,重点研究了不同的控制系统回路结构对弹体稳定特性的适应能力,为旋转弹控制系统设计提供更有针对性的参考。     

具有时滞和变消耗率的比率型Chemostat模型稳定性分析

研究了一类具有时滞和变消耗率的比率型Chemostat模型,讨论了边界平衡点和正平衡点的局部稳定性以及Hopf分支的存在性;利用比较原理和构造Lyapunov泛函,给出了边界平衡点和正平衡点的全局稳定性的充分性条件;并通过数值模拟验证了理论结果。     

考虑抗拉强度的含外倾结构面岩质边坡稳定性分析

当前工程设计都是将边坡失稳破坏看成整体的剪切破坏即M-C剪切破坏,基本不考虑岩土体本身抗拉强度.而岩质边坡真实的破坏应该是张拉-剪切复合破坏,不应是传统不考虑抗拉强度的单一剪切破坏模式.利用FLAC3D软件,基于张拉-剪切复合破坏准则对岩体和结构面强度参数同时进行强度折减,与只考虑抗剪强度的情况进行比较来研究抗拉强度对...     

李雅普诺夫判据在锁相环设计中的应用

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聚碳硅烷先驱体交联后热处理对陶瓷转化的影响

将聚碳硅烷交联产物在裂解前,先在200～400℃进行不同温度下的热处理,研究其对陶瓷转化过程的影响。结果表明,经400℃/2h热处理后,其裂解产物的陶瓷产率达到73 9%;裂解产物结构的主要缺陷为气孔,而未经热处理样品裂解产物结构的主要缺陷为裂纹。如果用该结构的陶瓷为基体,可以减少纤维损伤。