Two novel critical shock models based on Markov renewal processes

In this paper, we investigate systems subject to random shocks that are classified into critical and noncritical categories, and develop two novel critical shock models. Classical extreme shock models and run shock models are special cases of our developed models. The system fails when the total number of critical shocks reaches a predetermined threshold, or when the system stays in an environment that induces critical shocks for a preset threshold time, corresponding to failure mechanisms of the developed two critical shock models respectively. Markov renewal processes are employed to capture the magnitude and interarrival time dependency of environment-induced shocks. Explicit formulas for systems under the two critical shock models are derived, including the reliability function, the mean time to failure and so on. Furthermore, the two critical shock models are extended to the random threshold case and the integrated case where formulas of the reliability indexes of the systems are provided. Finally, a case study of a lithium-ion battery system is conducted to illustrate the proposed models and the obtained results.     

收发深度变化对浅海混响的影响研究

海洋中,由于种种原因可能造成声呐发射深度或接收深度发生变化,针对这一问题,研究了水听器的晃动给混响强度带来的影响。在波束位移射线简正波理论的基础上推导了浅海混响模型,仿真比较了负跃层浅海情况发射深度或接收深度上下变化1m时（小幅度变化）的混响衰减曲线,结果表明发射深度或接收深度上下变化1m时对混响衰减曲线的影响不大。可以认为水听器小幅度晃动时浅海混响相对于声源深度及接收深度是稳定的。     

悬浮式深弹拦截线导＋声自导鱼雷作战模型研究

水面舰艇如何使用悬浮式深弹拦截线导＋声自导鱼雷是舰艇防御鱼雷的重要问题之一。通过利用模糊数学知识将鱼雷报警距离分为近、中、远三个模糊区域，建立鱼雷报警距离隶属函数关系，预估鱼雷目标航向、航速等运动要素，最后建立了舰艇使用悬浮式深弹拦截线导＋声自导鱼雷策略模型；采用蒙特卡洛法通过计算机仿真，得出了悬浮式深弹在不同参数条件下拦截线导＋声自导鱼雷的概率。结果表明：舰艇进行规避机动其拦截概率可达32％～60％。