水下地形辅助导航技术的研究与应用进展

在简要介绍水下地形辅助导航基本概念的基础上,从地形辅助导航算法、水下数字地图技术、水下地形辅助导航试验等方面,详细介绍了水下地形辅助导航所涉及各方面的主要问题及研究进展,并对下一步研究方向及应用做出指引与展望。     

基于人工势场的潜艇搭载AUV回收路径规划

紧密结合未来无人作战侦察对潜艇搭载自主水下航行器(AUV)水下自主回收的需求,对水平面内基于水声定位的AUV的自主回收对接技术进行了研究。运用了基于人工势场的导引方法规划了AUV的回坞路径,然后基于AUV的运动方程设计了滑模跟踪控制律来解决AUV在复杂的回收环境下的避障问题,并通过引入"填平势场"来引导AUV走出局部极小点。最后采用了REMUS AUV的模型参数对水下回收进行了仿真试验研究,仿真结果验证了方法的有效性。     

美军临近空间飞艇项目建设情况及启示

介绍了美军临近空间飞艇项目建设概况;总结归纳了美军临近空间飞艇项目建设的主要经验与教训;根据美军临近空间飞艇项目建设的经验和教训,从科学制定发展规划、适度控制投入规模、逐一攻克关键技术、建立健全合作机制、寓军于民夯实基础5个方面提出了我军临近空间飞艇发展的对策建议。     

火箭发动机故障检测的快速增量单分类支持向量机算法

为解决液体火箭发动机故障诊断正负样本不平均问题,以及实现发动机稳态工作段自适应故障检测,建立了基于快速增量单分类支持向量机的异常检测模型。采取特征工程方法,对传感器获得的多变量时间序列进行特征提取。通过增量学习方法,对单分类支持向量机模型进行改进,并应用于液体火箭发动机异常检测,使单分类支持向量机检测模型具备对不同台次、不同工况的自适应性,提高了模型的计算速度。对多台次热试车数据的分析结果表明,该模型十分有效,训练速度快,具备实用价值。     

提取时间对硝基油漆稀料燃烧产物鉴定的影响

油漆稀料是一种常见的助燃剂,提取时间对其燃烧产物的鉴定会有一定的影响。选取了纯毛织品作为实验载体,以硝基油漆稀料为研究对象,对燃烧残留物及燃烧烟尘进行了系统的GC-MS分析,找出了纯样和加载油漆稀料后燃烧产物主要成分的变化规律,对样品中目标化合物的相对峰面积随燃烧产物提取时间的变化曲线进行了非线性数学分析,初步找出了样品燃烧产物的相对峰面积随硝基油漆稀料燃烧产物提取时间变化的规律,为合理选择物证的提取时间提出了建议。     

基于Mamdani模糊推理的航空发动机故障诊断

提出了一种基于Mamdani模糊推理的航空发动机故障诊断方法.该方法将发动机故障征兆信号作为模糊推理的输入,利用专家经验建立模糊推理规则并提取蕴含关系,在此基础上,通过故障征兆信号与蕴含关系的Mamdani推理合成获取发动机故障原因发生的可能性,进而达到故障诊断的目的.实验结果表明,该方法可行且有效.     

二阶非线性常微分方程组边值问题的正解

研究一类二阶常微分方程组两点边值问题,利用Krasnoselskii’s不动点定理,得到当f和g满足超线性或次线性时边值问题一个正解存在的充分条件.     

Evaluating the potential effects from probabilistic selling of similar products

In this article, we consider an online retailer who sells two similar products (A and B) over a finite selling period. Any stock left at the end of the period has no value (like clothes going out of fashion at the end of a season). Aside from selling the products at regular prices, he may offer an additional option that sells a probabilistic good, “A or B,” at a discounted price. Whenever a customer buys a probabilistic good, he needs to assign one of the products for the fulfillment. Considering the choice behavior of potential customers, we model the problem using continuous‐time, discrete‐state, finite‐horizon dynamic programming. We study the optimal admission decisions and devise two scenarios, whose value functions can be used as benchmarks to evaluate the demand induction effect and demand dilution effect of probabilistic selling (PS). We further investigate an extension of the base MDP (Markov Decision Process) model in which the fulfillment of probabilistic sales is uncontrollable by the retailer. A special case of the extended model can be used as a benchmark to quantify the potential inventory pooling effect of PS. Finally, numerical experiments are conducted to evaluate the overall profit improvement, and the effects from adopting the PS strategy. © 2014 Wiley Periodicals, Inc. Naval Research Logistics, 61: 604–620, 2014     

A nonatomic‐game model for timing clearance sales under competition

We deal with dynamic revenue management (RM) under competition using the nonatomic‐game approach. Here, a continuum of heterogeneous sellers try to sell the same product over a given time horizon. Each seller can lower his price once at the time of his own choosing, and faces Poisson demand arrival with a rate that is the product of a price‐sensitive term and a market‐dependent term. Different types of sellers interact, and their respective prices help shape the overall market in which they operate, thereby influencing the behavior of all sellers. Using the infinite‐seller approximation, which deprives any individual seller of his influence over the entire market, we show the existence of a certain pattern of seller behaviors that collectively produce an environment to which the behavior pattern forms a best response. Such equilibrium behaviors point to the suitability of threshold‐like pricing policies. Our computational study yields insights to RM under competition, such as profound ways in which consumer and competitor types influence seller behaviors and market conditions. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 365–385, 2014     

基于灰色决策的地形辅助导航区域选取方法

为避免仅利用单一地形特征参量对匹配区域可导航能力评判的不全面性,提出了一种基于灰色决策的多指标综合选取方法。首先,计算待选地形区域的地形标准差、地形熵、粗糙度及地形相关系数等表征地形特征的统计参量;然后,利用计算结果构建地形可导航性指标矩阵,通过无量纲化和归一化去除重叠信息;最后,求解理想决策并将决策向量投影于其上,得到地形可导航性评价。仿真表明:基于灰色决策的匹配区域选取方法能够兼顾不同特征参量所表征的地形固有属性,给出正确评价,且评价结果不受待选区域数目的限制。