基于残差决策的自动飞行控制系统远程实时故障诊断

针对自动飞行控制系统结构复杂、关联部件众多,发生故障时诊断时间长,从而影响飞机运行效率的问题,提出一种基于飞机通信寻址报告系统(ACARS)的远程实时故障诊断方案。首先,分析自动飞行控制系统的故障特点,设计搭建检测滤波器;然后,利用ACARS数据链实时发送的自动飞行控制系统的关键信息进行相关部件的残差计算,并根据残差决策算法进行故障诊断及定位;最后,针对不同故障部件残差间的差异大、决策门限无法统一的缺点,提出基于二次差值的残差决策改进算法,减缓了检测对象的整体变化趋势,降低了随机噪声和干扰的影响,避免了将瞬态故障诊断为系统故障的情况。实验仿真结果表明,基于二次差值的改进残差决策算法避免了多决策门限的复杂性,在采样时间为0.1 s的情况下,故障检测所需时间大约为2 s,故障检测时间大幅降低,有效故障检测率大于90%。     

Simultaneous determination of mycotoxin in commercial coffee

Mycotoxins are secondary metabolites produced by filamentous fungi that usually contaminate food products. Coffee is a natural product susceptible to mycotoxin contamination. The present study evaluates the presence of nivalenol, deoxynivalenol, T-2 and HT-2 Toxin, diacetoxyscirpenol, aflatoxin B₁, aflatoxin B₂, aflatoxin G₁, aflatoxin G₂, fumonisin B₁, fumonisin B₂, ochratoxin A, zearalenone, enniatin A, enniatin A₁, enniatin B, enniatin B₁, and beauvericin in coffee samples, using liquid chromatography tandem mass spectrometry (LC-MS/MS). The results show that zearalenone was not present in any sample. In the positive samples the contents of fumonisins ranged from 58.62 to 537.45 μg/kg, emerging mycotoxins ranged from 0.10 to 3569.92 μg/kg, aflatoxins ranged from 0.25 to 13.12 μg/kg, and trichothecenes, excepting nivalenol, ranged from 5.70 to 325.68 μg/kg. Nivalenol presented the highest concentrations, from 0.40 to 25.86 mg/kg. Ochratoxin A ranged from 1.56 to 32.40 μg/kg, and five samples exceeded the maximum limit established by the European Commission.     

An object replication algorithm for real-time distributed databases

A real-time distributed database system (RTDDBS) must maintain the consistency constraints of objects and must also guarantee the time constraints imposed by each request arriving at the system. Such a time constraint of a request is usually defined as a deadline period, which means that the request must be serviced on or before its time constraint. Servicing these requests may incur I/O costs, control-message transferring costs or data-message transferring costs. As a result, in our work, we first present a mathematical model that considers all these costs. Using this cost model, our objective is to service all the requests on or before their respective deadline periods and minimize the total servicing cost. To this end, from theoretical standpoint, we design a dynamic object replication algorithm, referred to as Real-time distributed dynamic Window Mechanism (RDDWM), that adapts to the random patterns of read-write requests. Using competitive analysis, from practical perspective, we study the performance of RDDWM algorithm under two different extreme conditions, i.e., when the deadline period of each request is sufficiently long and when the deadline period of each request is very short. Several illustrative examples are provided for the ease of understanding. Recommended by: Ashfaq Khokhar     

关于构建中国移动天地一体应急通信平台的探讨

为确保特殊时期党政军指挥通信畅通，充分利用中国移动现网资源，将卫星通信与地面光缆、微波传榆。以及移动网络无缝衔接，共同构建中国移动天地一体应急通信平台。     

无线电车载监测站的信号采集与通讯系统

本系统采用LabVIEW对无线电监测信号进行采集和处理．并开发用户界面。在Delphi平台上运用远程访问服务实现了无线电车载监测站与中心固定站的通讯。LabVIEW主程序对通讯子程序进行调用。     

Microwave Communication to Moving Parts Inside Machines

Cables to moving parts on a linear actuator in production machines, such as pick-and-place machines, are a source of unreliability owing to the possible breaking of a cable. They further reduce the positioning precision of the actuator owing to additional forces. Slotted waveguide systems for rail vehicles based on 2.4 GHz transmission frequency are well known, but transmitters/receivers and waveguides are bulky. The paper reports on the reduction in size of the equipment, adapted to 5.8 GHz using a commercial off-the-shelf RadioLan communication module. Further, the efficient termination of the wave-guide and a new way to reduce standing-wave effects is also discussed.     

DS1620实现的X射线采集板温度自动控制

DR是目前非常先进的X射线成像技术，将其X射线采集板工作温度控制在最佳工作范围可采集更好的图像。本系统采用PC和单独控制双模块分别控制温度，利用半导体传感器DS1620进行四路温度采集，通过单片机和PC串口通信，用PC通过半导体制冷芯片来控制X射线采集板的工作温度，在通信故障时也可以通过单独控制模块来控制采集板的温度。     

基于通信的港口管理系统的研究

讨论了如何利用Access7.0设计包含有通信的管理信息系统，并结合生产管理系统的实例。利用微软公司的Visual Basic中包含的通信控件，实现Windows95环境下通信程序的设计方法，介绍了通信控件的属性以及使用方法，给出了基本的通信程序。     

MEMS移相器及其在微型通信系统中的应用

从传统移相器的构造和原理出发，进一步分析了MEMS移相器的结构、特性。结果表明，MEMS移相器具有传统移相器所无法比拟的体积小、损耗小、成本低、频带宽、易于集成等突出优点。随着高阻硅衬底在微波领域应用的扩展，MEMS移相器介质损耗大幅度降低，将能与信号处理电路一同集成于硅衬底上，便于相控阵雷达等通信系统实现微小型化。     

即时通讯软件的安全性分析

在互联网服务中,即时通讯已成为了最流行的服务模式之一,人们对即时通讯的依赖程度也与日俱增。但是, 频频出现的病毒和黑客攻击使广大用户深受其害,即时通讯的安全问题也日益严峻。为了从根本上解决问题,本文对即时通讯软件的架构和协议进行了深入分析,目的是找出漏洞根源,给开发者和使用者提供防止漏洞的依据。