模糊神经网络的并联结构及其在噪声信号识别中的应用

采用模糊神经网络分类算法,提出了一种模糊网络的组合结构及多种组合算法．通过对辐射噪声信号的分类试验表明,该方法可充分利用多种特征子网络的模糊分类信息,显著地提高了网络的分类能力．     

COM文件加密的一种方法

本文在研究微机加密方法及磁盘噪信号后,提出利用噪信号作为一种识别标志,实现了,COM文件的加密。文中对加密的原理、方法及反解密方法进行了介绍。     

Robust shortest path problems with two uncertain multiplicative cost coefficients

We consider a robust shortest path problem when the cost coefficient is the product of two uncertain factors. We first show that the robust problem can be solved in polynomial time by a dual‐variable enumeration with shortest path problems as subproblems. We also propose a path enumeration approach using a K ‐shortest paths finding algorithm that may be efficient in many real cases. An application in hazardous materials transportation is discussed, and the solution methods are illustrated by numerical examples. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

YHFT-DX处理器全定制EDA技术的开发与应用

在YHFT-DX处理器的研制中,研究并实现了多项支撑全定制设计的EDA技术。针对全定制设计的功能验证,研究并实现了层次式功能模型自动提取技术,能够将晶体管级网表转化为等效的RTL级网表。研究并实现了晶体管级混合时序分析方法,可自动分析全定制设计的延时,并采用多线程并行的方法获得了约10倍左右的速度提升。为提高模拟结果分析的效率,开发了一个延时提取的工具Aimeasure。开发了两个信号完整性分析工具PNVisual和NoiseSpy,分别用于全定制设计的IR-Drop分析和噪声分析。上述技术已在YHFT-DX处理器的设计中得到了广泛应用,有效提高了全定制设计的效率与质量。     

Switching costs,dynamic uncertainty,and buyer–seller relationships

We analyze strategic relationships between buyers and sellers in markets with switching costs and dynamic uncertainty by investigating the scenario wherein a representative buyer trades with two foreign sellers located in the same foreign country. We show that, under exchange rate uncertainty, switching costs may lead to switching equilibria where both sellers co‐exist in the market with the buyer, or no‐switching equilibria where either seller captures the market. The presence of exchange rate uncertainty facilitates competition by allowing the sellers to co‐exist in the market with the buyer. However, if the level of uncertainty is beyond a threshold, the only viable equilibria are those where one of the sellers captures the market. Further, depending on the level of exchange rate uncertainty and the sellers' variable costs, switching costs may either raise or lower the level of prices in long‐term contracts between the buyer and the sellers. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

The impact of demand uncertainty on product line design under endogenous substitution

The existing product line design literature devotes little attention to the effect of demand uncertainty. Due to demand uncertainty, the supply‐demand mismatch is inevitable which leads to different degrees of lost sales depending on the configuration of product lines. In this article, we adopt a stylized two‐segment setup with uncertain market sizes and illustrate the interplay between two effects: risk pooling that mitigates the impact of demand uncertainty and market segmentation that facilitates consumer differentiation. Compared to downward substitution, inducing bidirectional substitution through product line decisions including quality levels and prices can yield greater risk pooling effects. However, we show that the additional benefit from the risk pooling effect cannot compensate for the reduced market segmentation effect. We demonstrate that the presence of demand uncertainty can reduce the benefit of market segmentation and therefore the length of product lines in terms of the difference between products. We also propose three heuristics that separate product line and production decisions; each of these heuristics corresponds to one particular form of demand substitution. Our numerical studies indicate that the best of the three heuristics yields performance that is close to optimality. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 143–157, 2015     

Technical note – operational statistics: Properties and the risk‐averse case

Consider a repeated newsvendor problem for managing the inventory of perishable products. When the parameter of the demand distribution is unknown, it has been shown that the traditional separated estimation and optimization (SEO) approach could lead to suboptimality. To address this issue, an integrated approach called operational statistics (OS) was developed by Chu et al., Oper Res Lett 36 (2008) 110–116. In this note, we first study the properties of this approach and compare its performance with that of the traditional SEO approach. It is shown that OS is consistent and superior to SEO. The benefit of using OS is larger when the demand variability is higher. We then generalize OS to the risk‐averse case under the conditional value‐at‐risk (CVaR) criterion. To model risk from both demand sampling and future demand uncertainty, we introduce a new criterion, called the total CVaR, and find the optimal OS under this new criterion. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 206–214, 2015     

多视图三角化中特征点噪声尺度的自适应估算

鲁棒性多视图三角化方法通常借助重投影误差经验阈值来剔除图像对应中的错误匹配,该经验阈值的选取直接影响三维重构场景点的数量和精度。在分析图像特征点定位噪声及对极传递几何原理的基础上,建立对极传递过程不确定性的传递模型,提出一种基于核密度估计的最优噪声尺度估算方法,并将该噪声尺度作为多视图三角化中错误匹配筛选的依据。实验结果表明,该方法可以获得准确的噪声尺度估计,从而有效提升多视图三角化方法的三维重构质量。     

三维模型大尺度坐标测量辅助设计与评估方法

针对大尺度产品三维模型坐标测量信息缺乏和面向任务坐标测量结果质量评价困难的问题,引入新一代产品几何量技术规范(GPS),提出了基于CATIA二次开发技术的坐标测量辅助设计方法,设计了CAD与CMM集成的XML数据结构,建立了坐标测量数据的UML模型;实现了符合新一代GPS要求的测量方案脚本化描述,开发了部分数据处理算法;提出了基于Monte Carlo方法的坐标测量不确定度评估方案和流程。基于以上技术开发了基于三维模型的大尺度坐标测量设计与评估系统并应用于飞机装配中的部件位姿测量,结果表明,设计的测量方案能够满足飞机柔性装配对接的要求,验证了上述方法的有效性。     

MEMS磁力线聚集和垂动调制磁场传感器

针对巨磁阻和磁隧道结等磁阻元件的1/f噪声,提出一种采用微机电系统的磁力线聚集和垂动调制磁场传感器。通过将被测磁场从低频转移到几kHz,实现对磁场的DC/AC转化,从而减小了磁阻元件的1/f噪声。基于该方案采用多层膜巨磁阻元件AA002制作了磁场传感器样品,并进行了实验测试,结果表明:磁传感器样品的调制效率达到了19.3%,超过了已有的其他各种调制方案,同时低频磁场的探测能力达到槡120pT/Hz,相比巨磁阻元件AA002提高了40多倍。