多参数融合的飞行品质评估模型的建立

目前航空管理机构与航空公司进行飞行品质评估主要是依据经验与简单飞行参数统计数字,这样做难以得出科学、客观的评估结果。基于提升全行业安全保障能力和运行品质的需求,研究了利用计算机技术对飞行品质进行综合评估的方法。选取了理想值逼近法作为飞行品质综合评估的手段,结合波动通道模型作为飞行品质评估的理论基础,基于提出的飞行品质评估模型对飞行品质评估系统进行了设计。对真实的飞行参数数据建立综合评估模型,同时考察多次航班的多个飞行参数,给出综合的飞行品质评估结论,为飞行评估、训练提供理论基础和科学的评判方法。     

基于ID3算法的民航直升机学员学习效果评估方法

针对难以准确预测民航直升机飞行学员执照理论考试是否能够通过问题,分析了各类决策树算法的应用情况,采用IC3算法对获取到的飞行学员执照理论学习过程中大量数据进行详细分析,构建了以IC3决策树算法为核心的学习效果评估模型,在此基础设计开发了基于移动互联网的评估平台.实践结果表明,本方法简单易行,通过平台评估为"通过"的飞行学员在随后的官方执照理论考试中均顺利过关,为今后直升机驾驶技术专业人才培养质量的提高起到较好的技术支撑作用.     

某型舰载直升机飞行模拟器飞行仿真系统设计

对某型舰载直升机飞行模拟器飞行仿真系统进行了设计研究.给出了某型舰载直升机飞行模拟器飞行仿真系统的模型框架.定义了建模过程中所涉及的主要坐标系,研究与分析了与主旋翼相关的诱导速度、挥舞角、拉力、扭矩的计算方法,给出了舰载直升机部件气动建模思路.最后,结合舰载直升机数据,对直升机飞行模拟器飞行仿真系统对舰载机飞行员的操纵响应进行了仿真分析.设计的舰载直升机飞行模拟器飞行仿真系统已经成功应用到了某型舰载直升机飞行模拟器上,具有仿真度高、实时性好等特点,起到了良好的训练效果,得到了舰载直升机飞行教员和学员的认可.     

基于飞参数据的飞行仿真模型验证方法研究

仿真模型验证已成为仿真研究的有机组成部分。为了更好地对飞行训练模拟器飞行仿真模型进行可信性评估,提高飞行训练模拟器飞行仿真模型的逼真性,将飞参数据应用于验证飞行训练模拟器飞行仿真模型的可信性。提出飞行仿真模型验证的验证方案,并对方案中的飞参解译、飞参数字滤波、飞行阶段识别及飞参数据插值处理等技术进行研究。介绍仿真模型验证量化评估的方法,包括时域分析法和频域分析法,并将这几种方法应用于某型飞行训练模拟器飞行仿真模型的验证,验证结果表明,利用飞参数据验证飞行仿真模型的方法完全可行。     

一种固定翼飞机飞行仿真动力学组件的开发

关于飞机动力学仿真系统设计问题,针对常规气动布局固定翼飞机飞行动力学的特点,给出了具有一般性的飞行动力学计算数学模型,并利用微软ATL组件技术开发了具有跨平台特性的飞行动力学计算组件,在计算功能和应用环境方面具有一定的通用性,可在飞行动力学仿真系统研发时应用,以提高飞行仿真系统研发效率及程序代码的重用性。利用在VC++6.0平台下搭建的MFC—OSG飞行仿真环境对组件进行了应用测试,验证了飞行仿真系统动力学计算模块开发采用组件技术的可行性,具有一定的参考及应用价值。     

飞行模拟器发展中的关键技术

飞行模拟器是现代航空工业中必备的基础设备,它以飞行仿真为主体;文中简单介绍了飞行模拟器的基本组成和关键技术的发展,并着重介绍了飞行模拟器的核心飞行仿真系统的组成、建模和验证以及计算机系统和模拟器的性能测试评估系统,以及上述系统在飞行模拟器中所起的作用,最后给出了几项关键技术的发展趋势。     

浅析提高飞行学员灵敏协调素质提高的方法与途径

飞行是一项非常特殊的职业,在三维空间运动,高度、速度、状态急剧发生变化,同时飞行具有高风险性,高技术性、职业的特殊性,对人的身体素质和综合素质有较高的要求。灵敏协调素质在综合素质里有重要的地位和意义。为打赢未来高技术条件下的局部战争,适应新型装备的发展要求,必须加强对飞行人员全面素质的培养,从思维上提高飞行学员中枢神经系统的支配能力及迅速、灵敏、协调一致的能力,使飞行人员的体能更适应飞行的需要,自如驾驶战机,真正实现"人机有机结合"。通过后天的培养和自身的努力使自己早日成为合格的、敢打必胜的、优秀的蓝天骄子。     

基于UML的飞行监控系统分析与设计

介绍了UML的概念和要点,应用UML对飞行监控系统进行了建模.给出了系统的体系结构并建立了飞行监控系统的用例模型、静态模型和动态模型,提高了系统的可靠性、可重用性和可维护性,为应用UML对大型飞行监控系统的建模进行了有益的尝试.     

基于注意力机制的飞行学员疲劳分类网络研究北大核心

近年的通用航空事故中,出现在飞行训练期间由人因引起的事故约1/3。疲劳是人因中重要的一种,准确地识别飞行学员的疲劳状态对飞行安全有积极意义。提出了一种融合注意力机制的飞行学员精神疲劳分类网络,使用深度可分离卷积对网络参数进行精简,引入注意力机制充分利用通道与空间特征对脑电无用信息进行抑制的同时增大了关键信息权重。使用公开疲劳数据集SEED-VIG对网络进行预训练,然后通过迁移学习将其应用于飞行学员精神疲劳分类,网络在对4种精神疲劳状态分类时达到了84.12%的准确率,并在NVIDIA Jetson Nano上达到了27samples/s的运行速度。该网络可有效识别飞行学员的疲劳类型,并及时向飞行教员反馈学员精神状态情况,为判断飞行学员是否适合训练提供生理依据,同时该网络满足移动设备和嵌入式设备的计算要求。     

基于JSBSim的运输机重装空投飞行仿真系统

针对传统飞机动力学模型通用性差、代码执行效率低、缺少重装空投动力学模型和评价指标等问题,改进了传统的分离体建模方法,建立了更加贴近实际的重装空投全量动力学模型.综合JSBSim、MATLAB、FlightGear三种软件的优点,研制一种运输机重装空投可视化飞行仿真系统.新设计的系统具有通用性强、运行速度快、易操作性、数据精度高、便于二次开发等优点.仿真对比分析了所提模型与现有空投模型之间的误差.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.