DeviceNet—Modbus协议转换器的设计及实现

介绍了DeviceNet-Modbus协议转换器的设计方法,即利用DeviceNet和Modbus都采用部分ISO/OSI模型标准的特点,完成了DeviceNet和Modbus两种网络的互联,并介绍了其硬件设计和DeviceNet网络基于仅限组2从站设备的软件实现方法。最终测试证明本设备可以满足实际需求。     

基于DN1022的DeviceNet总线产品设计

以基于CAN的DeviceNet技术为基础,采用DeviceNet从站协议芯片DN1022和意法半导体公司的32位单片机STM32F051R8T6为智能电机保护器设计一款DeviceNet从站模块,并介绍DeviceNet网络应用系统构建方法.     

基于DeviceNet总线的从设备通信适配器设计

基于DeviceNet总线的泵/阀控制器从设备通信适配器是用于智能泵/阀控制器与De-viceNet网络之间的通信协议设备,用于在智能泵/阀控制器和DeviceNet网络主设备之间交换I/O数据和其它设定数据.本DeviceNet总线从设备通信适配器是独立的智能化设备,由微处理器(W78E58)、双口RAM(IDT7005)、SJA1000CAN控制器、82C251 CAN收发器、状态指示发光管、微型开关、电源线路以及其它外围电子线路所组成.设计目的是使通信接口符合DeviceNet的协议规范.     

基于DeviceNet和RS-232/485/422的通信适配器的设计

DeviceNet是一种应用日益广泛的工业现场底层设备互联技术,详细介绍了以MCU为核心CPU的基于DeviceNet与RS-232/485/422多串口通信标准的通信适配器的设计,并给出了详细的硬件电路和软件设计流程.     

高速无线连接的“新宠”

与标准的企业无线网络的兼容性和11Mbps的传输速度,使802.11b无线网的吸引力越来越大。但是,无论是802.11b适配器还是访问节点(access point)的价格都比较高,这就意味着小型办公室和家庭用户或者选择HomeRF无线联网技术或者干脆放弃无线联网。 访问节点所扮演的角色是无线信号收发器和管理器并连接到有线网络。HomeRF不需要访问节点,而且HomeRF适配器也比     

DeviceNet现场总线从站通信接口的设计

DeviceNet是一种应用日益广泛的工业现场底层设备互联技术。文章详细介绍了以单片机为平台的DeviceNet现场总线从站接口的设计,并给出了详细的硬件电路和软件设计流程。     

让WLAN安全

产品特色:SMC2870W支持最新WPA安全标准802.11g,集成了无线网桥、无线AP、无线中继器和无线网络适配器多种功能于一身。它既可配置为无线A P,使用户可访问另一台无线802.11g和802.11b设备,也可用作中继器,通过支持无线分布系统(WDS),使用点对点或点对多点配置,扩展无线2.4GHz网络的范围,或作为无线网络适配器,将兼容以太网的任意设备接入到无线网络。     

基于DeviceNet总线的从设备通信适配器设计

基于DeviceNet总线的泵/阀控制器从设备通信送配器是用于智能泵/阀控制器与DeviceNet网络之间的通信协议设备,用于在智能泵/阀控制器和DeviceNet网络主设备之间交换I/O数据和其它设定数据。本DeviceNet总线从设备通信适配器是独立的智能化设备,由微处理器(W78E58)、双口RAM(IDT7005)、SJA1000 CAN控制器、82C251 CAN收发器、状态指示发光管、微型开关、电源线路以及其它外围电子线路所组成。设计目的是使通信接口符合DeviceNet的协议规范。     

DeviceNet配置监控系统

设计并实现了基于DeviceNet主从站配置的监控系统. 监控系统中的DeviceNet配置监控软件使用自定义协议通过串口实现了与主站通讯模块通信, 将主从站的各种信息, 如主从站配置, 从站参数值等数据传递到通讯模块上. 主站通讯模块通过标准的DeviceNet协议将上述信息传送到从站模块. 监控软件可以实时请求并获取从站信息, 并做出相应处理. 实验结果表明, 所涉及的数据通讯完全满足DeviceNet规范要求, 配置软件能够配置和监控DeviceNet总线通讯状况.     

DeviceNet现场总线中轮询协议的性能研究

基于DeviceNet协议生产者/消费者通信模型特点构建了其轮询通讯方式模型,轮询命令报文由主站广播至生产从站,轮询响应报文由生产从站通过主站周期地轮询每个生产从站广播至所有消费从站;文章采用Petri网的过程变迁TPN混合方法对DeviceNet总线协议进行了分析和研究,对其轮询通讯方式进行了模拟,讨论了响应时间、吞吐量等参数,分析了性能差异和响应快慢,根据文章的结论,现场总线的设计者可以很好的选择和设计满足自己需要的设计方案.     

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。     

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.