高可靠性1394总线传输线缆阻抗特性测试研究

面向新一代飞机的1394总线应用中,传输线缆作为总线传输介质,影响总线的传输特性。为满足新型机载1394线缆的高可靠性要求,本文对1394线缆的结构及差分阻抗进行了理论分析,提出了1394线缆的测试设备及测试环境,采用专用设备对1394线缆的差分阻抗进行了测试,测试结果表明,被测1394线缆满足线缆阻抗特性指标。在测试结论的支撑下,规范了1394线缆阻抗特性测试指标。为高可靠性1394线缆传输提供了理论依据及测试实验数据,为1394线缆的选型及应用奠定了基础,对构建整个1394总线具有指导意义并进而指导整个系统设计。     

1394总线关键协议分析与研究

在新一代飞机安全关键/任务关键系统中,对总线的实时性、确定性、可靠性提出更高的要求。1394总线协议通过规范强制根节点、静态分配通道号、纵向奇偶校验、STOF同步、异步流包通信及发送/接收端电气特性指标等约束,保证了总线传输的高实时、高确定及高可靠性。针对1394总线在安全关键/任务关键系统中的应用需求,分别从总线拓扑结构、总线包格式和总线可靠性三方面对1394总线关键协议进行详细分析与研究,为1394总线设计、实现及系统应用奠定了理论基础。     

一种1394总线分析逻辑电路的设计与实现

1394总线标准具有灵活、高速和可扩展的特性,为确保新一代航空1394总线系统功能、性能正确性,总线协议符合性及系统应用可靠性,对航空1394总线系统进行系统测试成为必要手段。提出了一种用于1394总线数据分析的逻辑电路,该逻辑电路内嵌于1394分析设备硬件中,可实现1394总线数据和状态的监控、分析和存储,再通过其主机接口读取分析结果。经过1394总线系统的联试、试验及试飞测试任务,充分表明该逻辑电路可有效监控分析1394总线,对于促进航空领域1394总线系统的研制具有重要意义。     

一种改进AS5643节点传输效率和容错性的方法研究

1394B作为成熟的商用总线,具有传输速率高、传输距离远、传输介质丰富等特点,并支持物理闭合环拓扑,具有一定的冗余可靠性。SAE AS5643在1394B总线的基础上,从实时性和确定性的角度出发,对1394B总线应用进行了一系列的扩展和约束,使1394B总线能够满足航空等领域的应用要求,但AS5643未能对传输效率和容错性进行详细的规定。文中研究和分析了AS5643标准定义的数据结构和传输特性,结合1394B总线协议的相关规定,提出了改进总线传输效率和容错性的措施。最后,利用FPGA逻辑和Link/PHY芯片实现了AS5643定义的CC/RN功能节点。经测试表明,文中提出的改进措施能够有效提高CC/RN功能节点的传输效率和容错性。     

一种IEEE1394总线监控卡的设计与实现

IEEE1394总线具有带宽高、延迟低、实时性强等特点,广泛应用于航空、航天领域。由于其差分总线上传输数据不透明,且协议复杂给设计开发带来极大困难。文中针对1394总线的原理和特点,分析了1394总线的监控需求,提出一种软硬协同实现的1394b总线监控方案。给出了相关的软件和硬件设计,实现网络中实时传输数据的监视和控制,采用软件对数据进行记录、存储、分析以及图形化显示,方便了数据的观测和结果分析。该设备的应用可为1394总线设备的开发与测试提供有效支持。     

Mil-1394b总线在飞行器管理系统中的典型应用分析

Mil-1394b是在COTS技术IEEE 1394b的基础上进行相应的扩展和约束来进行增强,以达到满足安全关键/任务关键系统所需的鲁棒性和确定性。Mil-1394b总线采用SAE AS5643标准,其全称为用于军事和飞行器应用的1394b总线接口需求,目的是标准化Mil-1394b在军事和飞行器中的安全关键/任务关键应用中的方法途径。提高了总线的可靠性和确定性,使Mil-1394b总线相比IEEE 1394b总线更适合作为安全关键的航空总线等高可靠场合的应用。Mil-1394b总线在美F-35战机、X-45、X-47无人机等飞行器管理系统已经相继得到使用,而在我国Mil-1394b总线作为飞行器管理系统总线的应用仍处于起步阶段,该文拟就Mil-1394b总线在飞行器管理系统中的典型应用进行分析。     

1394总线三节点仿真设备设计与实现

由于单纯依靠机载环境进行1394总线验证测试不仅成本高、风险大、资源有限,而且具有很大的局限性,所以急需开发相应的地面仿真设备进行总线系统综合化仿真测试。结合1394协议在领域的需求,研发了一种满足1394协议的总线三节点仿真设备,该设备实现控制计算机(CC)、远程节点(RN)、总线监控(BM)、加载维护(LM)一体化设计,集节点数据收发、配置加载、故障注入、通信监控、拓扑显示、远程加载等功能于一体,可用于实验室环境下搭建完整的1394总线通信系统,构建各机载子系统设备之间复杂的互联情况,全面系统地完成总线仿真应用测试,为领域的机载总线应用提供支持与保障。     

基于IEEE 1394总线的错误注入功能实现

IEEE 1394总线具有高可靠性、低延迟、带宽高、实时性强等特点，广泛应用于工业和航空航天领域。由于电子设备在航空航天领域的飞速发展，在其研发、设计和生产等各个环节也越来越复杂，从而导致其可靠性、稳定性等方面出现一系列问题，因此总线错误注入功能成为总线测试验证的强有力手段。上层应用软件给出错误注入的类型与总使能信号，给出了1394总线的错误注入功能的硬件实现，从而验证1394数据包是否符合协议，总线是否异常。     

基于AS5643协议的接口模块设计与实现

随着IEEE-1394总线成功应用于航空领域,IEEE-1394总线已成为新一代机载总线中的一员。为解决IEEE-1394总线在航空电子系统中的应用,满足机载环境的使用要求,符合AS5643协议对1394总线的确定性和可靠性要求。本文从硬件架构、FPGA逻辑架构和软件架构三个方面详细阐述了一种基于AS5643协议的接口模块的设计与实现,提出了一种基于FPGA逻辑实现AS5643协议的解决方案。最后通过实验验证,结果表明该模块满足设计指标,性能良好,实现了较高的传输速率,满足机载环境的应用需求。     

基于AS5643协议的接口模块设计与实现

随着IEEE-1394总线成功应用于航空领域,IEEE-1394总线已成为新一代机载总线中的一员。为解决IEEE-1394总线在航空电子系统中的应用,满足机载环境的使用要求,符合AS5643协议对1394总线的确定性和可靠性要求。文中从硬件架构、FPGA逻辑架构和软件架构三个方面详细阐述了一种基于AS5643协议的接口模块的设计与实现,提出了一种基于FPGA逻辑实现AS5643协议的解决方案。最后通过实验验证,结果表明该模块满足设计指标,性能良好,实现了较高的传输速率,满足机载环境的应用需求。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

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。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。