运载火箭伺服机构故障检测与诊断的扩展多模型自适应方法

针对运载火箭伺服机构故障,提出一种基于扩展多模型自适应估计的故障检测与诊断算法。建立考虑伺服机构故障的运载火箭姿态动力学模型;将故障角度作为状态变量得到增广状态空间模型;利用扩展卡尔曼滤波器进行状态向量和故障参数的非线性估计,并基于传感器测量数据采用假设检验算法在线计算故障发生的概率;给出基于扩展多模型自适应估计的故障检测与诊断算法流程。仿真结果表明,该方法在无故障时可对伺服机构进行健康监测;在单台伺服机构故障下,可以及时准确判断出哪一台芯级伺服机构发生故障,并可准确估计出伺服机构故障下的发动机摆角角度。     

On locally optimal independent sets and vertex covers

In this paper, we introduce a new notion of local optimality and demonstrate its application to the problem of finding optimal independent sets and vertex covers in k-claw free graphs. The maximum independent set problem in k-claw free graphs has interesting applications in the design of electronic testing fixtures for printed circuit boards [13]. For this problem, our concept of local optimality enabled us to devise an efficient heuristic algorithm which outperforms the currently best approximation algorithm by nearly a factor of two in terms of worst case bound. We believe that the idea of local optimality suggested in this paper can also be applied to other combinatorial problems such as the clique problem, the dominating set problem and the graph coloring problem. © 1996 John Wiley & Sons, Inc.     

模糊控制与其它控制技术的融合研究

介绍了模糊控制技术针对复杂控制对象进行的控制规则和隶属度函数算法的改进,以及与其它控制技术的融合研究,总结出多种控制融合方式,并在此基础上讨论了对更加复杂的研究对象的分析方法的可行性。     

建筑消防给水设计中几个问题探讨

本文讨论了建筑消防给水系统在日常管理、防火检查中存在的问题,提出在消防给水设计中应采取的措施。     

比对作战试验的定序指标考核研究

定性指标是武器装备作战试验中的重要考核内容,其中的定序指标是最为常见的一种定性指标.考虑到以比对试验的形式组织的作战试验,对于武器装备更新换代具有更好的决策支持作用,提出了一种考核框架及其样本量估算方法:剖析了当前作战试验定性指标考核的一些可改进方面,讨论了基于ridit分析的应用可行性与考核框架,并针对ridit分析...     

一种单轴旋转的车载IMU/DTU组合导航方法

长时间机动工况时,某些复杂路况和车况环境下,捷联惯导组合导航系统方位角误差将增大.基于已有组合导航算法框架,提出了一种基于单轴旋转调制的组合导航方法.采用21维IMU/DTU(里程计)误差状态构造状态方程,以捷联惯导解算的位移增量与里程计解算的位移增量之差作为观测量,Kalman滤波器融合惯导与里程计信息,利用旋转调制...     

Fulfillment by Amazon versus fulfillment by seller: An interpretable risk-adjusted fulfillment model

With dual-channel choices, E-retailers fulfill their demands by either the inventory stored in third-party distribution centers, or by in-house inventory. In this article, using data from a wedding gown E-retailer in China, we analyze the differences between two fulfillment choices—fulfillment by Amazon (FBA) and fulfillment by seller (FBS). In particular, we want to understand the impact of FBA that will bring to sales and profit, compared to FBS, and how the impact is related to product features such as sizes and colors. We develop a risk-adjusted fulfillment model to address this problem, where the E-retailer's risk attitude to FBA is incorporated. We denote the profit gaps between FBA and FBS as the rewards for this E-retailer fulfilling products using FBA, our goal is to maximize the E-retailer's total rewards using predictive analytics. We adopt the generalized linear model to predict the expected rewards, while controlling for the variability of the reward distribution. We apply our model on a set of real data, and develop an explicit decision rule that can be easily implemented in practice. The numerical experiments show that our interpretable decision rule can improve the E-retailer's total rewards by more than 35%.     

火炮射击冲击加速度信号提取方法研究

火炮结构在受到射击产生的冲击时易发生故障,最终影响火炮的寿命和性能。故障信号通常淹没在冲击加速度信号中,不易被识别。针对上述问题提出一种基于经验小波变换(EWT)和能量算子的信号提取方法,通过能量算子增强冲击响应特征,改进传统EWT的频谱分割方法,将火炮加速度信号分解为多个模态,有效地提取火炮的冲击特征。实验表明,改进后的EWT方法相对传统EWT对故障信号提取效果更好,时频图表现更清晰。