Responses of the upper middle atmosphere (60–110 km) to the stratwarms of the four pre-map winters (1978/9–1981/2)

The global developments of the four stratospheric events (～20–50 km) are described, using balloon, satellite and rocket data. Winds data for heights of 60–95 km, derived from L.F. drift (52°N, 15°E; Europe) and M.F. radar (52°N, 107°W; Canada), are then compared with the stratospheric data. There is clear evidence that the preliminary planetary waves often penetrate strongly to ～90 km, and that mean wind reversals also occur. However, there are dramatic differences between European and Canadian mesospheric responses.     

某新型飞机维修模拟训练系统

介绍了某新型飞机维修模拟训练系统的设计思路以及系统组成和特点,并结合系统的实现讨论了模拟仿真技术应用于装备维修的现实意义.实践证明,应用该系统开展飞机维修模拟训练解决了部队由于维修保障训练设备缺乏,机务人员难以进行全专业综合保障维修训练的难题,大大缩短了新机维修保障训练周期,节约了大量的装备维修保障经费.     

超音速进气道线性动力学

 Willoh提出的数学分析法需先给出计算点沿进气道流路各截面气流静态参数值后,才能计算小扰动下该计算点的线性动力学特性。本文提出了采用Palmer与王乃行的进气道简便静态特性计算法,以求取计算点下超音速段各道斜激波前、后气流静态参数值,再按一元、无粘、绝热、集总参数、管流求取亚音速段各截面的气流静态参数     

ACSS for paralleled multi-inverter systems with DSP-based robust controls

An averaged current-sharing strategy (ACSS) for paralleled multi-inverter systems with digital signal processor (DSP)-based robust controls is presented. With an ACSS, the inverters are in parallel operation and each inverter has a voltage robust controller to achieve system stability and robustness, and a current robust controller to track the averaged inductor current of the inverters to achieve equal current distribution. In the proposed system, the current-sharing control loop is independent of the voltage control loop. Therefore, equal current distribution among the inverters, fast response, and tight regulation can be achieved. Additionally, the ACSS in each inverter can be readily implemented with two operational amplifiers. Simulation results and hardware measurements or a single-inverter system and a two-inverter system, and simulation results of a three-inverter system with linear and nonlinear loads have demonstrated the feasibility of the proposed control scheme in equal current distribution and fast regulation.     

Data association for deghosting in Y-shaped passive linear array sonars

This paper deals with data association using three sets of passive linear array sonars (PLAS) geometrically positioned in a Y-shaped configuration, fixed in an underwater environment. The data association problem is directly transformed into a 3D assignment, which is known to be NP hard. For generic passive sensors, it can be solved using conventional algorithms, while in PLAS, it becomes a formidable task due to the presence of bearing ambiguity. Thus, the central issue of the problem in PLAS is how to eliminate the bearing ambiguity without increasing tracking error. To solve this problem, the 3D assignment algorithm used the likelihood value of only those observed bearing measurements is modified by incorporating frequency information in consecutive time-aligned scans. The region of possible ghost targets is first established by the geometrical relation of PLAS with respect to target. The ghost targets are then confirmed and eliminated by generating multiple observations in consecutive scans. Representative simulations demonstrate the effectiveness of the proposed approach.     

刹车与起落架抖动的相互影响

就刹车与起落架抖动的相互影响,分析了现象的实质,建立起了起落架支柱的刚度、机轮转速、滚动半径、振动周期和防滑刹车系统设定的打滑量与刹车力矩之间的定量关系,以期从整体上解决起落架－机轮刹车装置－防滑刹车系统组成的一个全系统的匹配问题,达到刹车无抖动的目的。     

Analysis of multiframe target detection using pixel statistics

Current track-before-detect (TBD) algorithms are developed and analyzed using a path statistic for each potential object trajectory. However this path statistic does not characterize overall performance gain. We propose a pixel-based statistic. This allows the TBD approach to be characterized as an image enhancement algorithm with detection gains compared with single frame detections. It is shown that for the TBD approach to have superior detection over single frame detection the target signal-to-noise ratio (SNR) must be greater than a threshold SNR in order to overcome the uncertainty in the target path. Tradeoffs are made for a class of velocity constrained target paths in terms of the detection gain with respect to the maximum target velocity and number of frames integrated     

边缘网络下多无人机协同计算和资源分配联合优化策略

针对边缘网络环境下多人机之间存在计算负载不均，造成卸载任务失败的问题，提出了一种多无人机间协作的智能任务卸载方案。通过联合考虑多无人机任务分配、计算资源分配和无人机飞行轨迹，引入公平性指数建立了无人机公平负载最大化和能量消耗最小化问题。基于多智能体深度强化学习框架，提出了融合轨迹规划和任务卸载的分布式算法。仿真结果表明，所提出的多无人机协作方案可以显著提高任务完成率和负载公平度，并且有效适用于大规模用户设备场景。