参量型空气折射率传感系统

本系统分别利用传感器测出空气的温度、气压和湿度三个参量,把测量值用一个通用于不同机型的接口电路连接到微机进行数据处理并计算出空气折射率值。文中叙述了传感器及其检测电路的设计原理,给出了检测和接口电路框图、计算公式和程序流程图。整个系统已通过联机调试和初步的对比试验。     

Exploration and implementation of commonality valuation method in commercial aircraft family design

Commercial aircraft family design can reduce development costs, shorten development cycles, and expand the market coverage of aircraft. Commercial aircraft family development has become one of the most important features of modern aircraft design. This paper explores the effects of commonality on different aircraft models in a commercial aircraft family. The existing product commonality indexes are summarized and their limitations in the application to aircraft design are discussed. Then a new component commonality index is proposed based on the component decomposition structure. A model for calculating the aircraft program value is established,which considers development costs, manufacturing costs, sale price, operation costs and residual costs. The effects of aircraft commonality on time and economic costs of both development and manufacturing, and on sale price, are analyzed and quantified. The commonality evaluation strategy is obtained, which features comprehensive consideration of the aircraft program value and time costs. The break-even analysis of aircraft is proceeded on the basis of costs and price data. By using a real option method, the strategy considers the uncertainty of the aircraft program and the flexibility of the manufacturer. This strategy proves to be rational and applicable to aircraft design based on the calculation of three examples and the analysis of parameter sensitivity.     

基于脑电功率谱密度的作业人员脑力负荷评估方法

脑力负荷状态的准确识别对减少因作业人员无效脑力负荷导致的人因事故具有重要意义。针对人-机系统中作业人员脑力负荷客观评估问题开展了基于MATB-Ⅱ平台的3种不同脑力负荷水平下的航空情境实验，记录16名被试的NASA任务负荷指数（NASA-TLX）量表数据和脑电（EEG）信号，提出了一种基于脑电功率谱密度（PSD）和支持向量机（SVM）的个体脑力负荷评估方法。结果表明：随着实验设计脑力负荷水平增加，被试的主观脑力负荷得分显著提高（p<0.001），这表明该实验任务设计较好地诱发了低负荷、中负荷和高负荷情境。在此基础上，通过网格搜索法确定个体脑力负荷评估模型的统一优化参数，惩罚系数取3 000，核函数参数取0.000 1，模型测试正确率达到0.966 5±0.029 8，宏平均的受试者工作特征曲线下的面积（Macro-AUC）达到0.991 0±0.011 4。本文为作业人员脑力负荷状态的客观和准确评估提供了一种新的办法，为后期作业人员脑力负荷状态的实时判别提供模型基础。     

An improved approach for rainfall estimation over Indian summer monsoon region using Kalpana-1 data

In this paper, an improved Kalpana-1 infrared (IR) based rainfall estimation algorithm, specific to Indian summer monsoon region is presented. This algorithm comprises of two parts: (i) development of Kalpana-1 IR based rainfall estimation algorithm with improvement for orographic warm rain underestimation generally suffered by IR based rainfall estimation methods and (ii) cooling index to take care of the growth and decay of clouds and thereby improving the precipitation estimation.     

某型飞机数字防滑刹车控制盒可靠性分析与设计

对某型飞机数字防滑刹车控制盒的可靠性进行了分析,利用工程加权法对控制盒进行了可靠性分配,并通过元器件可靠性预计法对控制盒的可靠性进行预计.对比及验证表明,控制盒可靠性设计合理,满足主机及系统要求.     

基于数据包络分析的民航发动机维修效果评价

对民航发动机维修效果进行评价可以为发动机承修厂的选择提供决策支持,同时有助于发现发动机承修厂的潜在问题。为了实现发动机维修效果的评价,首先提出了评价指标选择的原则,在此基础上给出了发动机维修效果评价指标体系,建立了基于数据包络分析的C2WH模型的发动机维修效果评价模型,并对模型的构建过程进行了描述。针对决策单元输入输出...     

舰载机着舰指标体系构建

舰载机着舰的难度很大、要求很高,而着舰系统的复杂性又使得指标要求涉及很多方面。为了从整体上明确着舰的指标要求,从而有利于着舰理论和工程等研究,整理了公开文献中分散的指标要求,并梳理了指标间的逻辑关系,最终构建了着舰指标体系,将指标归纳到总体框架中。研究结果对着舰的控制与分析等具有一定的参考价值。     

Availability modeling for periodically inspection system with different lifetime and repair-time distribution

Availability is a main feature of design and operation of all engineering system. Recently,availability evaluation of periodical inspection systems with different structures is at the center of attention due to the wide application in engineering. In this paper, an analytical and probabilistic availability model for periodical inspection system is proposed by a new recursively algorithm,which can achieve limiting average availability and instantaneous availability of periodical inspection system under arbitrary lifetime and repair-time distributions. Then three application examples are presented, the systems lifetime and repair-time are respectively fellow exponential/exponential,Weibull/normal and Weibull/lognormal distribution. Finally, a Weibull/lognormal system is studied to analyze the dynamic relationship between inspection period and availability. The results indicate that the proposed approach can provide the technology support for improving system availability and determining reasonable inspection period.     

A new structural reliability index based on uncertainty theory

The classical probabilistic reliability theory and fuzzy reliability theory cannot directly measure the uncertainty of structural reliability with uncertain variables,i.e.,subjective random and fuzzy variables.In order to simultaneously satisfy the duality of randomness and subadditivity of fuzziness in the reliability problem,a new quantification method for the reliability of structures is presented based on uncertainty theory,and an uncertainty-theory-based perspective of classical Cornell reliability index is explored.In this paper,by introducing the uncertainty theory,we adopt the uncertain measure to quantify the reliability of structures for the subjective probability or fuzzy variables,instead of probabilistic and possibilistic measures.We utilize uncertain variables to uniformly represent the subjective random and fuzzy parameters,based on which we derive solutions to analyze the uncertainty reliability of structures with uncertainty distributions.Moreover,we propose the Cornell uncertainty reliability index based on the uncertain expected value and variance.Experimental results on three numerical applications demonstrate the validity of the proposed method.     

α-l型区间可靠性分析方法及其工程应用

在区间非概率可靠性模型的基础上,以区间长度l和区间下限α为结构系统变量的输入参数,重新定义了一种新的可靠性指标,分析得到了这种可靠性分析方法的判定依据;在此基础上,在线性和非线性条件下讨论了结构可靠度的计算方法.以某型飞机防冰引气管结构为例,进一步探讨了所提方法在共振可靠性分析当中的工程应用.