信息物理系统在航空领域中的应用

面向航空电子系统的新需求,对信息物理系统在机载领域的应用进行了探索。通过研究信息物理系统的基本概念和特征,提出机载信息物理系统的简化模型,分析需解决的关键技术,肯定了信息物理系统在航空领域应用的可行性。     

Closed-form posterior Cramer-Rao bounds for bearings-only tracking

We address the classical bearings-only tracking problem (BOT) for a single object, which belongs to the general class of nonlinear filtering problems. Recently, algorithms based on sequential Monte-Carlo methods (particle filtering) have been proposed. As far as performance analysis is concerned, the posterior Cramer-Rao bound (PCRB) provides a lower bound on the mean square error. Classically, under a technical assumption named "asymptotic unbiasedness assumption", the PCRB is given by the inverse Fisher information matrix (FIM). The latter is computed using Tichavsky's recursive formula via Monte-Carlo methods. Two major problems are studied here. First, we show that the asymptotic unbiasedness assumption can be replaced by an assumption which is more meaningful. Second, an exact algorithm to compute the PCRB is derived via Tichavsky's recursive formula without using Monte-Carlo methods. This result is based on a new coordinate system named logarithmic polar coordinate (LPC) system. Simulation results illustrate that PCRB can now be computed accurately and quickly, making it suitable for sensor management applications     

环下润滑结构内部流动分析和收油叶片结构优化研究

为了研究环下润滑结构内部流动并优化收油叶片结构,根据环下润滑结构内部高转速、强旋流的流动特点建立了数值计算模型,分析了原始结构的油气两相流动并总结了滑油的损失机理,在此基础上提出收油叶片的优化改进结构,详细讨论了不同收油叶片结构对环下润滑内部流动和收油效率的影响规律。研究结果表明,原始结构中滑油冲击主轴产生的碰撞飞溅和在离心作用下沿收油叶片被向外甩出均是引起收油效率下降的原因;优化收油叶片结构后的气流速度在叶尖附近的最大增加幅度不超过4m/s;收油叶片叶根拐角处采用圆弧过渡且叶根延伸后的收油效率仅在低转速范围内略高于原始结构的收油效率,收油效率最大提升了1.03%;在此基础上增加阶梯结构并进一步延伸叶根后可在全部转速范围内提升收油效率,相对原始结构的收油效率最大可提升接近5.0%。     

主体性德育观视域下的高职思想政治理论课教学改革

主体性作为一个重要的哲学范畴,对当代高职思想政治理论课教学改革产生了深远的影响。主体性德育观是当代高职思想政治理论教学人本理念的必然嬗变,针对当前高职思想政治理论教学中存在的问题,探讨了生成与彰显主体性是当代高职思想政治理论教学改革追求的必然诉求。     

Coherent matter wave inertial sensors for precision measurements in space

We analyze the advantages of using ultra-cold coherent sources of atoms for matter-wave interferometry in space. We present a proof-of-principle experiment that is based on an analysis of the results previously published in Richard et al. (2003) from which we extract the ratio h/m for ⁸⁷Rb. This measurement shows that a limitation in accuracy arises due to atomic interactions within the Bose–Einstein condensate. Finally we discuss the promising role of coherent-matter-wave sensors, in particular inertial sensors, in future fundamental physics missions in space.     

Adaptive sensitive frequency band selection for VMD to identify defective components of an axial piston pump

The underlying study investigates single valued neutrosophic entropy based adaptive sensitive frequency band selection for variational mode decomposition(VMD) for the purpose of identifying defective components in an axial pump. The proposed methodology is applied in the following steps. First, VMD is applied for decomposing vibration signals into various frequency bands, called as modes. After computing energy of each VMD, the lower(minimum) and upper(maximum) bounds from these energy readings ...     

基于启发式算法的可重构性指标分配

串联有约束条件下的可重构性指标分配问题,针对考虑部件故障的系统给出了可重构度的概念和计算方法,并论证了其合理性.结合最优冗余分配理论和可重构度定义给出了可重构度最大化的冗余分配模型,在此基础上提出了基于启发式算法的可重构性指标分配方法,该方法可解决约束条件内资源优化配置问题,并得到系统最大可重构度的解.直接寻查法作为以往具有代表性的最优冗余分配方法,用作系统可重构性指标分配仿真,与所提方法作比较,结果显示基于启发式算法的可重构性指标分配方法较前者有更高的有效性.     

A second-order numerical method for elliptic equations with singular sources using local flter

The presence of Dirac delta function in differential equation can lead to a discontinuity,which may degrade the accuracy of related numerical methods.To improve the accuracy,a secondorder numerical method for elliptic equations with singular sources is introduced by employing a local kernel flter.In this method,the discontinuous equation is convoluted with the kernel function to obtain a more regular one.Then the original equation is replaced by this fltered equation around the singular points,to obtain discrete numerical form.The unchanged equations at the other points are discretized by using a central difference scheme.1D and 2D examples are carried out to validate the correctness and accuracy of the present method.The results show that a second-order of accuracy can be obtained in the fltering framework with an appropriate integration rule.Furthermore,the present method does not need any jump condition,and also has extremely simple form that can be easily extended to high dimensional cases and complex geometry.     

空域管理和评估系统中空域辅助系统的设计

研究了空域辅助设计系统的设计方法,其目的是能够在给定的环境中由计算机实现信息采集、处理,通过与用户的交互,自动完成飞行程序设计工作。