智能化工业以太网故障诊断体系研究

传统的工业以太网故障诊断系统智能化程度较低,无法预测故障,且成本较高。阐述了一种智能化的故障诊断体系并对其进行了分析,提出了一种建立在数据仓库、联机分析处理(OLAP)、决策支持系统(DSS)和数据挖掘技术基础上并适合于工业以太网的故障诊断解决方案,并探讨了一些实现的方法。     

基于PC/104总线的飞机电源产品综合测试系统

详细介绍了一套基于PC／104总线和虚拟仪器技术的飞机电源产品综合测试系统的功能和软硬件实现原理。阐述了测试系统的设计原理，最后结合整个系统设计介绍了在LabVIEW环境下测试系统软件的设计和实现。     

Object-based representations of spatial images

Object based representations of image data enable new content-related functionalities while facilitating management of large image databases. Developing such representations for multi-date and multi-spectral images is one of the objectives of the second phase of the Alexandria Digital Library (ADL) project at UCSB. Image segmentation and image registration are two of the main issues that are to be addressed in creating localized image representations. We present in this paper some of the recent and current work by the ADL's image processing group on robust image segmentation, registration, and the use of image texture for content representation. Built upon these technologies are techniques for managing large repositories of data. A texture thesaurus assists in creating a semantic classification of image regions. An object-based representation is proposed to facilitate data storage, retrieval, analysis, and navigation.     

软硬件协同设计在远置终端系统设计中的应用

首先,对系统软硬件进行统一描述与建模;其次,重点介绍了动态规划法评估系统时间性能的方法和线性加权和法构造适应度函数的方法,并将两种方法与遗传算法相结合解决软硬件划分问题;最后进行了仿真,结果表明该方法能够有效的解决软硬件划分中的多目标优化设计。     

基于多传感器的裂纹扩展监测研究

疲劳裂纹扩展是结构健康监测的主要问题之一，为了保证金属结构的可靠和安全运行，实时监测结构的疲劳裂纹扩展过程十分必要。针对结构裂纹扩展的问题，采用压电传感器（PZT）和电阻应变片两种传感器，提出结合能够连续监测结构损伤的被动监测方法以及对微小损伤敏感的主动监测方法对裂纹扩展进行综合监测，以提高裂纹扩展的监测水平。采用随机森林算法对裂纹长度进行识别，并使用D-S证据理论对两种传感器的识别结果进行数据融合，得到比单一传感器更准确、可靠的裂纹扩展识别结果。进行了基于应变和主动Lamb波的裂纹扩展监测实验研究，验证了该方法对提高裂纹扩展监测识别准确率的有效性和实用性。     

智能抽油井示功仪

本文介绍了一种基于微控制器的抽油井示功仪的硬件结构、软件设计及其工作原理，并介绍了一种快速测试方法，即单周期测试法。     

基于飞行器的飞行导航与飞行控制数据综合的研究

针对基于双处理器结构的飞控计算机数据综合过程中的时间同步、时间管理问题,采用了初始同步和周期同步相结合的方式,对任务运行中的误差进行了修正,并在时间同步的基础上,将控制链条分解成若干个控制单元进行分时调度,实现了双机并行处理.同时对数据综合过程中的数据处理方式也进行了讨论.     

云计算综述

论述了云计算的起源、概念、特点,与分布式计算和网格计算的区别;介绍了云计算厂商,及各厂商采用的数据存储、数据管理、编程模式、提供的服务种类云计算存在的问题,特别是云计算安全的风险种类及防护方法。提出了云计算需解决的问题。     

Reducing variability in short term orbital lifetime prediction

Within the last year three major re-entries occurred. The satellites UARS, ROSAT and Phobos-Grunt entered Earth’s atmosphere with fragments reaching the surface. Due to a number of uncertainties in propagating an object’s trajectory the exact place and time of a satellite’s re-entry is hard to determine. Major influences when predicting the re-entry time are the changing precision of the available orbital data, the satellite’s ballistic coefficient, the activity of the sun which influences the Earth’s atmosphere and the underlying quality of the atmospheric model. In this paper a method is presented which can reduce the variability in short-term orbital lifetime prediction induced by fluctuating orbital data accuracies. A re-entry campaign is used as a reference for this purpose. For a window of a few weeks before the re-entry the position data of a synthetic object is disturbed considering different degrees of orbital data errors. As a result different predictions will exist for the generated position data of a given day. Using a regression algorithm on the available data an average position is obtained, which is then used for the orbital lifetime prediction. The effect of this measure is a more consistent prediction of the orbital lifetime. The paper concludes with the comparison of the generated re-entry windows in various test cases for the original and the averaged data.     

用输入数据符号加权减小MSK信号的带外功率

由于最小频移键控信号具有较为理想的功率谱特性，近年来已得到广泛关注，但在某些场拾它的带外能量泄漏不能满足实际需要。在此情况下可以对输入数据符号进行加权处理，从而得到一类ＭＳＫ信号这类ＭＳＫ信号仍为等幅波，相位仍保持连续。本文给出了这类信号功率谱的计算公式以及加权函数和功率谱的关系，并给出实例。