结合动态时间弯曲与决策树方法的液体火箭发动机故障诊断

对某大型液体火箭发动机的热试车数据及通过发动机模型仿真得到的故障数据进行动态时间弯曲分析,得到弯曲路径集,然后结合决策树方法进行了故障检测和诊断。对于故障试车没有出现漏报警和误报警,对于正常试车没有出现误报警。通过与神经网络、支持向量机等方法所得结果的对比,证明该方法可以成功地应用于火箭发动机的故障检测和诊断。     

基于贝叶斯方法的退化失效型产品实时可靠性评估

通过传统可靠性方法得到的失效分布反映了相同受试环境下同一类产品的平均特征,并不能直接应用于系统实时定量可靠性分析。为此,针对有历史试验数据的退化失效型产品,依据局部更新的思想,利用贝叶斯方法最大可能地采用现场测试数据,并将之及时反映到实时可靠性模型中去。结果表明,随着融合现场数据的增多,产品的实时可靠性模型也逐渐全面反映出产品的个性特征。     

一种快速有效的循环平稳信号检测方法

TSAE-Z算法把时间切片自相关包络检测和可变步进的Zoom-FFT检测相结合,实现了对循环平稳信号的快速、精确检测,仿真结果表明,在相同数据长度条件下,TSAE-Z算法能够使检测运算时间减少3个数量级;在相同执行时间的条件下,TSAE-Z算法能在提高检测分辨率的同时使检测性能提升6dB以上。     

Two-agent scheduling with linear resource-dependent processing times

This paper considers a two-agent scheduling problem with linear resource-dependent processing times, in which each agent has a set of jobs that compete with that of the other agent for the use of a common processing machine, and each agent aims to minimize the weighted number of its tardy jobs. To meet the due date requirements of the jobs of the two agents, additional amounts of a common resource, which may be in discrete or continuous quantities, can be allocated to the processing of the jobs to compress their processing durations. The actual processing time of a job is a linear function of the amount of the resource allocated to it. The objective is to determine the optimal job sequence and resource allocation strategy so as to minimize the weighted number of tardy jobs of one agent, while keeping the weighted number of tardy jobs of the other agent, and the total resource consumption cost within their respective predetermined limits. It is shown that the problem is -hard in the ordinary sense, and there does not exist a polynomial-time approximation algorithm with performance ratio unless ; however it admits a relaxed fully polynomial time approximation scheme. A proximal bundle algorithm based on Lagrangian relaxation is also presented to solve the problem approximately. To speed up convergence and produce sharp bounds, enhancement strategies including the design of a Tabu search algorithm and integration of a Lagrangian recovery heuristic into the algorithm are devised. Extensive numerical studies are conducted to assess the effectiveness and efficiency of the proposed algorithms.     

地空导弹C3I决策系统的Petri网建模与性能分析

对地空导弹决策系统的结构和性能进行了研究.对基于旅营两级决策组织导出的库所/变迁系统进行了描述,建立了较为完善的决策系统的Petri网模型.并引入了决策时延这一反应指挥决策系统能力的重要性指标.这些问题的解决对提高C3I决策系统的实时性和准确性具有十分重要的意义.     

改进相空间重构方法在混沌识别中的应用研究

讨论了传统非线性时间序列相空间重构方法的特点,提出了一种改进的相空间重构方法.为了揭示非线性时间序列中的非线性相关性,采用了一种基于关联积分的统计量,并研究了不同参数对它的影响.研究了延迟时间和嵌入维数之间的关系,并采用时间窗口描述这2个参数的变化规律.同时,应用改进方法计算了混沌时间序列的重构参数,重构了混沌信号的吸引子.研究结果表明,该方法能够从时间序列有效地重构原系统的相空间,为混沌信号识别提供了新的途径.     

Dynamic policy for idling time preservation

This study aims to determine and evaluate dynamic idling policies where an agent can idle while some customers remain waiting. This type of policies can be employed in situations where the flow of urgent customers does not allow the agent to spend sufficient time on back-office tasks. We model the system as a single-agent exponential queue with abandonment. The objective is to minimize the system's congestion while ensuring a certain proportion of idling time for the agent. Using a Markov decision process approach, we prove that the optimal policy is a threshold policy according to which the agent should idle above (below) a certain threshold on the queue length if the congestion-related performance measure is concave (convex) with respect to the number of customers present. We subsequently obtain the stationary probabilities, performance measures, and idling time duration, expressed using complex integrals. We show how these integrals can be numerically computed and provide simpler expressions for fast-agent and heavy-traffic asymptotic cases. In practice, the most common way to regulate congestion is to control access to the service by rejecting some customers upon arrival. Our analysis reveals that idling policies allow high levels of idling probability that such rejection policies cannot reach. Furthermore, the greatest benefit of implementing an optimal idling policy occurs when the objective occupation rate is close to 50% in highly congested situations.     

某型机械装备修复性维修时间的分布拟和

对某型机械装备基层级修复性维修时间进行了统计分析,确定了维修时间的分布形式、分布参数及各种维修时间参数值。     

一种推广的连续情形经济投资模型

随着序列情形费用型投资模型和折扣投资模型的解决，本文对其进行连续推广，并给出一个明确的停止规则。     

关于线性时变系统的逆

本文讨论单输入单输出线性时变系统的逆系统问题，给出了可逆性的充要条件和两种降阶逆系统的计算方法，并用例子说明了这些方法。