一种改进的混合BLISS多学科设计优化方法

针对BLISS 2000优化过程中权值系数的引入给实际应用带来的困难,提出一种改进的BLISS优化过程——混合BLISS( Hybrid BLISS,HBLISS).该方法在保持BLISS 2000的基本算法结构的基础上取消权值系数,利用耦合变量的最小残差协调子系统级和系统级优化,给出了HBLISS的算法结构和基本流程...     

一种自适应指数加权衰减记忆滤波算法

根据衰减记忆因子为一个常数的不尽合理性的假设,深入研究了指数加权衰减记忆滤波因子,根据滤波收敛条件和滤波模型准确时的新息(残差)特点,提出了具有自适应性、抑制滤波发散的指数加权衰减记忆滤波算法,并通过仿真试验验证了自适应抑制滤波发散的有效性。     

基于组合赋权雷达图实现电网电能质量综合评估

将改进的组合赋权雷达图方法用于电网电能质量综合评估。对主观、客观赋权法组合,基于组合权重与原权重之间的偏差尽可能小的优化思想,求取雷达图中各项指标的组合权值。利用各指标对应的扇形区域的对角线作为指标轴绘制雷达图,不仅最大限度体现各指标的独立权重,也反映了各指标之间的相互影响。利用雷达图的面积和周长两个变量完成对电能质量的综合评估。最后通过应用实例,验证了论文方法的合理性和在电能质量综合评估中的有效性。     

Demand forecasting by temporal aggregation

Demand forecasting performance is subject to the uncertainty underlying the time series an organization is dealing with. There are many approaches that may be used to reduce uncertainty and thus to improve forecasting performance. One intuitively appealing such approach is to aggregate demand in lower‐frequency “time buckets.” The approach under concern is termed to as temporal aggregation, and in this article, we investigate its impact on forecasting performance. We assume that the nonaggregated demand follows either a moving average process of order one or a first‐order autoregressive process and a single exponential smoothing (SES) procedure is used to forecast demand. These demand processes are often encountered in practice and SES is one of the standard estimators used in industry. Theoretical mean‐squared error expressions are derived for the aggregated and nonaggregated demand to contrast the relevant forecasting performances. The theoretical analysis is supported by an extensive numerical investigation and experimentation with an empirical dataset. The results indicate that performance improvements achieved through the aggregation approach are a function of the aggregation level, the smoothing constant, and the process parameters. Valuable insights are offered to practitioners and the article closes with an agenda for further research in this area. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 479–498, 2013     

基于备件需求预测的两步法理论

在对备件需求时间序列研究的基础上,结合指数平滑法和Croston法的特点,分析了指数平滑法与两步法的原理,通过对指数平滑法和两步法方差的研究,得到两步法是指数平滑法的一般形式的结论,为两步法的进一步研究提供一定的理论支撑。     

Two‐stage component test plans for testing the reliability of a series system

A system reliability is often evaluated by individual tests of components that constitute the system. These component test plans have advantages over complete system based tests in terms of time and cost. In this paper, we consider the series system with n components, where the lifetime of the i‐th component follows exponential distribution with parameter λ_i. Assuming test costs for the components are different, we develop an efficient algorithm to design a two‐stage component test plan that satisfies the usual probability requirements on the system reliability and in addition minimizes the maximum expected cost. For the case of prior information in the form of upper bounds on λ_i's, we use the genetic algorithm to solve the associated optimization problems which are otherwise difficult to solve using mathematical programming techniques. The two‐stage component test plans are cost effective compared to single‐stage plans developed by Rajgopal and Mazumdar. We demonstrate through several numerical examples that our approach has the potential to reduce the overall testing costs significantly. © 2002 John Wiley & Sons, Inc. Naval Research Logistics, 49: 95–116, 2002; DOI 10.1002/nav.1051     

高超声速滑翔飞行器变轨段自适应跟踪制导方法

针对高超声速滑翔飞行器变轨段大偏差条件下的标准轨迹跟踪问题,提出一种基于权值矩阵自适应修正的变轨段跟踪制导方法。分析了变轨段主要控制方式和标准轨迹特性;将简化的纵向运动方程在标准轨迹附近线性化;采用将误差项引进线性二次型性能指标加权矩阵的方式,设计了改进的权值自适应修正跟踪制导方法。CAV-H飞行器仿真分析表明,该方法能够实现高超声速滑翔飞行器变轨段高精度自适应跟踪制导,对初始及过程偏差具有良好的鲁棒性。     

基于向量相似度的组合赋权方法

针对多属性决策中属性权重的确定问题,提出了一种基于向量相似度的主、客观权重的集成方法。用权向量的相似度作为不同赋权方法重要性的度量,意义明确,计算简单,可操作性强。最后结合算例验证了此方法的有效性和实用性。     

改进的粒子群神经网络在飞控中的应用

针对BP神经网络对初始值敏感、容易陷入局部寻优且收敛速度较慢,提出用粒子群对神经网络的参数进行优化,同时设计了衰减的指数函数对惯性权重进行动态调整以提高算法性能.并应用该算法对导弹飞控系统的逆误差进行补偿,仿真结果表明,该方法对逆误差进行了有效的补偿,避免了局部寻优并提高了学习效率.     

基于ABA处理和幅度加权的频率捷变单脉冲雷达角闪烁抑制技术

针对频率捷变幅度加权角闪烁抑制方法进行改进,提出了一种基于ABA(amplitude-based angle)处理的幅度加权角闪烁抑制方法。首先将单个脉冲测角的结果限制在一定范围内,然后对多个脉冲测角的结果进行幅度加权,仿真表明这种方法在各种信噪比条件下的角闪烁抑制性能都要大大优于常规的幅度加权方法。