提高惯导系统Unscented卡尔曼滤波实时性技术

Unscented卡尔曼滤波(UKF)通过构造一组,具有与给定状态估计相同的一、二阶矩,也可能是高阶矩的样本点,实现对非线性系统的状态估计,因此其计算效率取决于能够捕获这些数字特征的样本点数目.通过构造n 2个样本点来捕获n维状态变量的均值和方差,提出了将这种方法应用于惯性导航的初始对准.仿真结果表明在同等滤波精度的情况下,该方法比UKF计算效率更高,实时性更好.     

Dynamic order acceptance and capacity planning on a single bottleneck resource

We present a tactical decision model for order acceptance and capacity planning that maximizes the expected profits from accepted orders, allowing for aggregate regular as well as nonregular capacity. The stream of incoming order arrivals is the main source of uncertainty in dynamic order acceptance and the company only has forecasts of the main properties of the future incoming projects. Project proposals arrive sequentially with deterministic interarrival times and a decision on order acceptance and capacity planning needs to be made each time a proposal arrives and its project characteristics are revealed. We apply stochastic dynamic programming to determine a profit threshold for the accept/reject decision as well as to deterministically allocate a single bottleneck resource to the accepted projects, both with an eye on maximizing the expected revenues within the problem horizon. We derive a number of managerial insights based on an analysis of the influence of project and environmental characteristics on optimal project selection and aggregate capacity usage. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

谈算法研究

算法是计算机程序设计的核心。本文结合实际应用,通过研究算法所取得的成效,说明算法研究的必要性和重要作用。     

42－160柴油机离合器换向拨叉叉头优化设计的光弹验证

本文用光弹性实验方法验证了有限元法对４２—１６０柴油机离合器换向拨叉优化设计的结果。实验证明,有限元优化设计是正确、可靠的,效果是非常好的。     

表格驱动程序设计方法

本文提出了一种具有广泛应用前景的程序设计方法——表格驱动(Formdriven)程序设计方法(以下简称表格驱动法)。文中首先描述了表格驱动法的基本思想、解的结构;分析了这种方法的特点与适用性;剖析了基于表格驱动法的办公自动化软件ALL-IN-1的设计思想,并指出表格驱动法特别适合于设计软件开发工具。     

用非线性规划求解有限推力最优交会

利用非线性规划方法研究了航天器的有限推力最优交会问题。这种方法利用了近年来发展起来的直接优化技术,用分段多项式来表示整个轨道的状态和控制向量,将最优控制问题转化为非线性规划问题。在应用这种方法时,先将整个轨道分为若干推力段和无推力段,然后利用配置方法产生推力段的约束段,利用状态转移矩阵来产生无推力段的约束。最后,对共面轨道情况下的交会进行了数值仿真,验证了方法的有效性和鲁棒性。     

The stochastic single resource service‐provision problem

The service‐provision problem described in this paper comes from an application of distributed processing in telecommunications networks. The objective is to maximize a service provider's profit from offering computational‐based services to customers. The service provider has limited capacity and must choose which of a set of software applications he would like to offer. This can be done dynamically, taking into consideration that demand for the different services is uncertain. The problem is examined in the framework of stochastic integer programming. Approximations and complexity are examined for the case when demand is described by a discrete probability distribution. For the deterministic counterpart, a fully polynomial approximation scheme is known 2 . We show that introduction of stochasticity makes the problem strongly NP‐hard, implying that the existence of such a scheme for the stochastic problem is highly unlikely. For the general case a heuristic with a worst‐case performance ratio that increases in the number of scenarios is presented. Restricting the class of problem instances in a way that many reasonable practical problem instances satisfy allows for the derivation of a heuristic with a constant worst‐case performance ratio. Worst‐case performance analysis of approximation algorithms is classical in the field of combinatorial optimization, but in stochastic programming the authors are not aware of any previous results in this direction. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

非线性系统中的机动目标跟踪算法

对于非线性系统中的机动目标跟踪问题 ,首先针对“当前”统计模型的缺陷提出了一种修正算法 ,然后应用转换测量Kalman滤波算法进行跟踪。仿真结果表明在非线性观测条件下 ,算法明显提高了对弱机动和非机动目标的跟踪性能 ,同时保持了对强机动目标的高性能跟踪     

神经网络模型预测函数控制方法

在建立基于神经网络模型的非线性预测函数控制系统结构和基于BP网络非线性预测模型的基础上,提出了基于神经网络模型的非线性预测函数控制方法,并对其优化法等进行了讨论。通过与PID方法的仿真比较表明,预测函数控制方法具有抑制干扰能力强、跟踪性能好的特点,能够满足一些非线性系统的控制要求。     

A parallel machine replacement model

This paper considers a finite horizon parallel machine replacement problem where a fixed number of machines is in operation at all times. The operating cost for a machine goes up as the machine gets older. An older machine may have to be replaced by a new one when its operating cost becomes too high. There is a fixed order cost associated with the purchase of new machines. Machine purchase prices and salvage values may depend on the period in which they were purchased. The objective is to find a replacement plan that minimizes the total discounted cost over the problem horizon. We believe that the costs in our model are more commonly observed in practice than those previously used in the literature. The paper develops properties of optimal solutions and an efficient forward‐time algorithm to find an optimal replacement plan. A dominance property is developed that further limits the options to be considered, and a simple forecast horizon result is also presented. Future research possibilities are mentioned. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 275–287, 2002; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/nav.10012