综合航电开放式软件设计技术

综合航电开放式软件设计技术是新一代航电系统支持平台机载实时容错分布式计算机系统的重点,它的设计直接或间接地关系到新一代综合航电系统的性能和成本.针对先进综合航电系统的特点、性能要求,对目前机载计算机软件系统存在的可靠性、安全性低,不易移植,成本高,层次分割不清晰,功能独立性差,对系统容错支持能力弱等缺陷,提出了"三层栈结构"的软件设计新思想,通过标准接口(物理接口和逻辑接口)使得层与层,模块与模块之间得以分开,实现了功能模块化、软硬件隔离性、软件的再利用性、可剪裁性、易维护性,以适应不断增长的航空电子系统任务能力需求,为新一代航电系统支持平台机载实时容错分布式计算机系统的开发、研制提供了可靠的保证.     

基于PXI的航电系统综合自动测试设备的研制

本文采用PXI仪器作为测试平台,综合运用GPIB仪器技术、虚拟仪器技术、仿真技术等,自动完成对LUR的控制、激励、性能和功能的测试,成功解决了机载航电系统自动化检测的问题。     

面向信号的仪器类驱动器设计与实现

针对自动测试系统（ATS）仪器可互换性的实现问题,借鉴IEEE1641信号与测试定义标准（Signal and Test Definition,STD）和IVI（Interchangeable Virtual Instrument）仪器类驱动思想,采用COM（Component Object Model）组件技术完成了基于信号接口的仪器类驱动器设计,同时实现了对不同种类开关的模型化描述和统一控制。该仪器驱动器在机载电子设备测试系统中得到实际的应用,实现了具有相同信号性能的同类仪器及不同仪器间的互换,减少了ATS升级维护的成本和时间。     

OBSUS:一种高效的机载软件更新系统仿真评价

航空电子产业中航电综合化是目前航电系统发展的主要趋势,在综合化航电系统中,越来越多的功能模块采用软件实现,来代替硬件的相应功能,同时软件系统是需要不断更新的,因此软件更新系统的作用显得尤为重要。围绕航电系统中的软件更新关键技术,通过研究机载环境及其软件更新的特点,提出一种新型机载软件更新系统OBSUS(On-Board Software Update System)。通过OBSUS系统架构设计,以及通信协议Xmodem+的实现,使得OBSUS可部署在多种硬件平台中,以满足机载环境软件更新的要求,具有较强的普适性。最后,在真实硬件平台上实现了OBSUS原型系统,并对系统的性能进行了仿真研究与性能评价。仿真验证结果表明,OBSUS是一种高效的机载软件更新系统。     

基于FC网络上的机载分布式系统设计

机载分布式操作系统是新一代航电系统支持平台机载计算机系统的重点，其设计影响到新一代综合航电系统的性能和成本。该文分析了机载分布式操作系统的特点及性能，提出了三层栈结构的软件设计思想。通过标准接口(物理接口和逻辑接口)使得层与层、模块与模块之间得以分离，实现了功能模块化、软硬件隔离性、软件的再利用性、可剪裁性和易维护性，以适应航空电子系统任务能力的新需求。     

某型机载超短波抗干扰电台自动测试系统的设计

介绍了某型机载超短波抗干扰电台自动测试系统(ATS)的设计.该系统采用基于C语言的面向信号的自动测试系统软件,利用无线电综合测试仪、跳扩频信号模拟器及宽带功率计等测试资源,实现了对机载超短波抗干扰电台的自动检测.     

一种机载航电系统光背板的设计与应用

针对机载航电系统光互联网络高密度、高可靠及抗恶劣环境等特点,在对比了印制光—电路板及光纤电路技术优缺点的基础上,引入MT光纤接口,基于光电混装连接嚣,设计并实现了一种应用于机载航电系统的光背板,并对其进行了测试和实验验证;结果表明:光背板各路MT接口的光损值控制在要求范围内,且通过了高低温、冲击振动等抗恶劣环境试验,能满足机载航电系统应用需求,是一种值得推广的方法。     

机载光电探测仿真系统的研究

光电探测系统仿真是近年来世界各国重点发展和研究的一种应用仿真技术.文中介绍了基于1553B总线和以太网的一种机载光电探测仿真系统的设计与实现.详细讨论了机载光电探测仿真系统的功能、组成、设计特点并给出了具体的硬件和仿真软件的实现方法.该机载光电探测仿真系统可模拟光电探测系统在各种工作方式下的工作.将该系统应用于综合航电火控仿真系统试验,验证了综合航电火控系统的可行性与正确性,并已经在光电探测系统的设计和研制过程中取得了良好的效果.     

综合航电系统健康管理体系结构设计

健康管理体系结构是军用综合航电系统的重要组成部分,关系到综合航电系统和战机安全性、生存性、维护性等多方面.概述了综合航电系统的结构组成,剖析了健康管理的内涵.通过论述系统、环境和人对系统失效行为的影响,归纳了系统失效类型,明确了健康管理体系结构设计的三方面需求.在此基础上,提出了一种新的健康管理体系结构,并完成了机载部分和地面部分的基本结构设计,分析了系统健康信息处理流程,最后就下一步要研究的问题进行了探讨.     

机载中央维护系统通信建模及实现

针对国内民航领域内难以从机载中央维护系统(CMS)自主获取航电系统维护数据的问题,研究提取维护数据的技术并予以实现.通过CMS系统的解析和研究,建立中央维护系统各交联计算机之间的通信模型,实现维护测试的工作模式,设计了中央维护系统接口仿真器,实现对真实航电组件维护数据的提取和显示;最后,通过在实际航电系统环境下的联合测试,验证仿真器对维护总线数据的处理能力.测试结果表明,仿真器能够可靠地解码和提取现代民用飞机航电系统维护总线数据,满足航电系统集成仿真验证的需求.     

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。     

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.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).