随着嵌入式市场不断扩张,从个人消费端到工业领域,越加丰富多样的硬件平台,快速发展的软件生态,使得构建嵌入式Linux操作系统变得困难.嵌入式Linux操作系统不仅要满足不同领域的专业需求,还要考虑硬件平台对系统的限制条件.针对上述问题,提出了采用Yocot开源项目进行定制化嵌入式Linux操作系统的方法.首先通过配置文件得到构建环境;其次编写自定义层,满足定制化需求;最后调用构建引擎bitbake解决软件组件之间的依赖与冲突,生成目标镜像,完成定制化嵌入式Linux操作系统任务.该方法的结果显示Yocto开源项目不仅可以保留Linux软件生态的丰富性,还能适用于任何类型硬件架构的嵌入式设备.

为了解决现有时间序列的分段线性表示方法忽略时间序列的全局特征, 局限于局部最优的问题, 本文通过研究时间序列的趋势, 发现了时间序列的波动特性, 将时间序列的趋势变化分为上下两层, 在上下两层分别剔除趋势保持点. 实验结果表明, 该分段方法时间复杂度低、且易于实现, 在保持时间序列趋势特征的基础上, 得到的拟合误差更小.

飞行品质监控(FOQA)是一种主动性地预防和减少飞行事故的安全监管技术手段,利用飞机上安装快速存取记录器(QAR)记录的大量飞行参数数据、飞机状态监控(ACMS)报告数据及相关信息,分析监控飞行品质.中国民航从1997年开始实施QAR工程,目前基于手机无线网络的无线快速存取记录器(WQAR)技术已经十分成熟,该技术相对于传统的快速存取记录器而言,具有系统可靠性高、数据传输自动完成、数据加密安全性好、使用费用低廉等特点,我国民用商业运输飞机70％以上的机队已经安装并使用WQAR.

Extracting and using goal orderings is a way to improve efficiencies of planning algorithms. During extracting goal orderings, some of existing methods can only deal with atomic goals of a specific problem that will introduce too much redundant work, and the others deal with predicates of a planning domain that can not extract enough goal orderings. The paper addressed an abstract method to extract goal orderings. The method used unification to identify different instantiations of a predicate when dealing with predicates. It can not only reduce redundant work during extracting, but also get enough goal orderings.

Compared with Linux NFS's access control basd on host, this paper puts forward a way to realize NFS service based on user resource management with Windows OS.

As the increasing clients of NFS server, the flaws of access-cotrol of NFS server become more and more obvious. This paper introduc the principle and the implementation of adding ACL function to NFS server, which can strengthen the power of access-control in NFS server. It c enhance the security of NFS server.

This paper introduces a user-oriented secure communication model implemented in network layer for two trusted network nodes. The model adopts role-based access control mechanism and trust management based on X.509 certificates. The implementation of the model is introduced.

In1995,Wu proposed a smart card-oriented remote login authentication scheme based on a geometric approach.The scheme has a very low computational complexity,so it is very suitable for security application based on smart card.Hwang pointed out insecurity involved in the scheme in1999.Recently,Chien gave further a different approach to break the scheme and also proposed a modified scheme which can with-stands the security attacks found by Hwang and Chien.In this paper,authors do further cryptanalysis of scheme proposed by Wu and point out some other insecurity still involved in the scheme,of which Hwang and Chien have been unaware.

The paper describes communication mechanism be-tween PC and USB device and the USB device structure designed for multi -floppies working platform developped by author.Fur-thermore,the design idea of impleme nting communication between PC and USB device is also presented.