基于OpenGVS半潜船操作模拟器视景系统的研究

为了满足半潜船作业人员学习和培训的需要,有必要在航海模拟器大环境下研发半潜船操作模拟器仿真系统。以船舶静力学为基础,实现了半潜船装载重大件货物的过程的动态稳性计算,以Visual C++6.0和OpenGVS场景管理软件为开发平台,研制开发了半潜船操作模拟器应具备的视景系统。该仿真系统实现了视点的转移和跟踪,通过设置在半潜船的驾驶台、甲板及外部三个虚拟相机,实时动态显示半潜船各种运动的状态,同时实现了半潜船操作模拟器几个模块间的相互通信,取得了很好的效果。     

Fault containment in weakly stabilizing systems

Research on fine tuning stabilization properties has received attention for more than a decade. This paper presents probabilistic algorithms for fault containment. We demonstrate two exercises in fault containment in a weakly stabilizing system, which expedite recovery from single failures, and confine the effect of any single fault to the constant-distance neighborhood of the faulty process. The most significant aspect of the algorithms is that the fault gap, defined as the smallest interval after which the system is ready to handle the next single fault with the same efficiency, is independent of the network size. We argue that a small fault gap increases the availability of the fault-free system.     

Containment control of multi-agent systems with unbounded communication delays

In this paper, we address the containment control problem for multi-agent systems under heterogeneous unbounded communication delays with emphasis on the convergence rate analysis. Different from most works on multi-agent systems, we resort to a viewpoint from the area of positive delay systems. We first cast the containment control problem into the stability analysis of an associated error system. In order to capture the convergence rate, we introduce a nondecreasing positive function whose reciprocal represents the decay rate of the associated error system. Under the assumption that each follower has access to at least one leader and some mild hypotheses on the communication delays, an explicit condition is given to characterise the decay rate of the associated error system in terms of linear programming. In addition, we provide several special cases when the communication delays are restricted by linear, sublinear and logarithmic growth rates, respectively. Finally, through numerical examples, it is shown that the convergence rate is dominated by the delays being the highest order infinitely large quantity.     

A low‐complexity design for distributed containment control of networked pure‐feedback systems and its application to fault‐tolerant control

This paper addresses a low‐complexity distributed containment control problem and its extension to fault‐tolerant control for networked nonlinear pure‐feedback systems under a directed graph. The multiple dynamic leaders are neighbors of only a subset of the followers described by completely non‐affine multi‐input multi‐output pure‐feedback dynamics. It is assumed that all followers' nonlinearities are heterogeneous and unknown. The proposed containment controller is implemented by using only error surfaces integrated by performance bounding functions and does not require any differential equations for compensating uncertainties and faults. Thus, compared with the previous containment control approaches for multi‐agent systems with unknown non‐affine nonlinearities, the distributed containment control structure is simplified. In addition, it is shown that the proposed control scheme can be applied to the fault‐tolerant containment control problem in the presence of unexpected system and actuator faults, without reconstructing any control structure. It is shown from Lyapunov stability theorem that all followers nearly converge to the dynamic convex hull spanned by the dynamic leaders and the containment control errors are preserved within certain given predefined bounds. Copyright © 2016 John Wiley & Sons, Ltd.     

Coordinated control with multiple dynamic leaders for uncertain Lagrangian systems via self‐tuning adaptive distributed observer

This paper studies coordinated control of multiple Lagrangian systems with parametric uncertainties subject to external disturbances by proposing a fully distributed continuous control law based on the improved self‐tuning adaptive observer inspired by non‐identifier‐based high‐gain adaptive control technique. Under this distributed continuous control law, a group of Lagrangian systems are driven to the convex hull spanned by multiple heterogenous dynamic leaders, which can be any combination of step signals of arbitrary unknown magnitudes, ramp signals of arbitrary unknown slopes, and sinusoidal signals of arbitrary unknown amplitudes, initial phases, and any unknown frequencies. It is also worth to mention that this control law we propose, depending neither on any information of leader systems for uninformed followers, nor on external disturbances, even independent of neighbors' velocity, can achieve asymptotic tracking of multiple leaders without any additional condition instead of ensuring the ultimate boundedness of the containment error as in the literature. Copyright © 2016 John Wiley & Sons, Ltd.     

基于云重心理论的舰艇部队作战油料保障能力评估

为评估舰艇部队作战油料保障能力,根据舰艇部队作战油料保障特点和相关要求,从油料储存能力、油料运输能力、油料补给能力、快速反应能力、组织筹划能力、抢修抢险能力6个方面构建了评估指标体系,采用云重心理论建立了舰艇部队作战油料保障能力评估模型,并结合实例对模型进行了验证.结果表明,该方法能有效融合主客观信息,解决评估过程中定性与定量间的不确定性转换,减少评估过程中模糊性和随机性的影响,提高舰艇部队作战油料保障决策的科学性.     

基于电子海图的水面无人艇全局路径规划研究

为解决水面无人艇全局路径规划问题,提出一种基于电子海图的距离寻优Dijkstra算法。该算法使用动态网格模型,克服了传统Dijkstra算法占用内存大的问题,可以减少规划时间,提高规划精度。仿真结果表明,采用的环境模型表示方法以及路径规划算法可以生成安全、合理的航线。     

New approach to the automatic segmentation of coronary artery in X-ray angiograms

For the segmentation of X-ray angiograms （XRA）, the essential feature and the prior knowledge of angiographic image were analyzed, and a multi-feature based fuzzy recognition （MFFR） algorithm was proposed to infer the local vessel structure in this paper. Guided by the prior knowledge of artery vessel, a probability tracking operator （PTO） can rapidly track along the artery tree, and walk across the weak region or gaps because of disturbance or preprocessing to angiographic image. Another, the accurate measurement of the vascular axis-lines and diameters can be synchronously implemented in the tracking process. To correctly evaluate the proposed method, a simulated image of CAT and some clinical XRA images were used in the experimentations. The algorithms performed better than the conventional one： given one start-point, on average 92.7% of the visible segments or branches was automatically delineated; the correctness ratio of vessel structure inference reached to 90.0% on the average.     

压力容器失效概率的计算方法

本文从质检部门统计的万台事故率入手,通过横向比较各台容器的设计、制造、安装、使用、维修改造等各个环节质量,然后通过统计,建模以及经验公式等方式,量化每个指标,设计出压力容器失效概率的计算公式。有了失效概率这个参数,就可以对压力容器的快速检验,安全分级,风险预测提供支持。