C8051F021在滚动轴承测试中的应用

C8051F021是一款完全集成混合信号单片机。本文将其应用到滚动轴承测试中,实现了便携式滚动轴承测试仪,提高了系统性能和系统集成度。文中介绍了系统的硬件结构,并给出了数据采集的关键程序。     

嵌入式协议栈缓冲区管理的简化实现方法

本文针对嵌入式系统网络协议栈的特点,设计了一种简洁、高效、且对存储资源要求很少的缓冲区管理策略。该策略基于缓冲区单次拷贝技术,克服了有些嵌入式系统存储控制器低效的存储块拷贝。除了提供缓冲区管理例程,还实现了缓冲区的动态分配与回收。最后,我们将实现源代码移植到X86嵌入式裸机平台的64K PCI扩展ROM中,基于该缓冲区管理设计了TCP/IP协议,并已经应用于无本地存储设备的超级刀片服务器上。     

基于特定协议的串口通信与远程控制的实现

以微软公司的MSComm串口通信控件为低层接口,在特定的串口通信协议的基础上,利用串口实现了在计算机中采集高精度测角仪的测试数据,完成了PC机对测角仪的远程控制,为高精度测角仪在自动化检测中的应用提供了一种新的方法。     

基于GSM GPS短消息的车载移动终端的设计与实现

为了解决对城市车辆进行实时监督和统一管理的问题,基于GPS全球定位系统和GSM数字蜂窝网,以性价比较高的AVR微控制器开发设计了GPS车载移动终端设备.终端通过GPS获取当前位置和时间信息,并以短消息的形式通过GSM网络发往监控中心,在中心的电子地图上实时地显示出来.同时监控中心的控制指令,如跟踪监听,遥控设置等,通过GSM网络发往车辆上的终端设备,从而实现了系统的交互运作.终端功耗低,体积小,操作简单,便于在系统升级和维护.     

嵌入式Internet的实现技术与安全问题分析

本文简要介绍了嵌入式系统相关理论、嵌入式Internet的基本概念以及嵌入式系统接入Internet的条件,重点讨论了嵌入式系统接入Internet的实施方案,并对嵌入式Internet的安全机制与防御方法进行了详细论述。     

全热线体育彩票销售系统的安全性简析

本文简要分析了“全热线”体育彩票销售系统的网络实现,阐述了该系统的关键技术,分析了它所采取的主动安全性及被动安全性措施,以及可能遭受的攻击及相应对策。     

广铜半连铸炉及1.5t炉增容后的供电改造

针对半连铸的生产扩大，增加炉子设备，供电增容及原设计的不足之处进行供电系统改造，以满足扩大生产的需要。     

中国铝箔轧制装备正在与世界先进水平接轨

本文介绍了中国铝箔轧制设备经历的三个发展阶段，根据采集到的不同阶段的统计数据，对中国铝箔轧制设备与世界先进轧制设备进行了比较和分析，指出中国铝箔轧制设备无论是在数量上还是在装机水平上都正在与世界接轨。     

QoS Model of a Router with Feedback Control

The Internet has evolved into a shared, integrated platform of a broad range of applications with different Quality‐of‐Service (QoS) requirements. Routers are an important part of the Internet and play a critical role in assuring QoS. A router is usually placed between two networks to receive data packets from one network and then transmit those data packets to another network if necessary. Data packets are the actual units of data traveling on computer networks. A data packet has two parts: header and data. The data carries messages, such as e‐mail text, from computer applications. The header carries information that is required to control and manage the transmission of the data packet on computer networks. Existing approaches for providing QoS involve prediction or estimation for traffic characterization to determine parameters required of static traffic admission control. However, prediction or estimation inaccuracy in traffic characterization can result in inappropriate parameter settings for static admission control and, in turn, compromise QoS or resource utilization. This study presents a QoS model of a router with feedback control that monitors the state of resource usage and adaptively adjusts parameters of traffic admission control to overcome prediction or estimation inaccuracy and achieve a balance between QoS and resource utilization. The QoS model of a router with feedback control is simulated to test its performance on QoS and resource utilization in both heavy and light traffic conditions. The performance of the QoS model of a router with feedback control is also compared with that of two basic QoS models of a router with static admission control using admission control parameters resulting from over‐ and under‐characterization of traffic, respectively. The simulation results show that the QoS model of a router with feedback control achieves a better balance between QoS and resource utilization than the basic QoS models with over‐ and under‐characterizations of traffic in the heavy traffic condition. This study also shows that the three models of routers demonstrate similar QoS performances and resource utilization in the light traffic condition. Copyright © 2005 John Wiley & Sons, Ltd.     

贮氢合金表面处理改善吸放氢性能研究

研究表面改性对La系合金贮氢性能的影响,采用化学镀的方法,对LaNi5和LaNi4.7Al0.3合金进行了镀Pd的表面处理实验.在p-C-T测试系统上研究了镀Pd前后,LaNi5和LaNi4.7Al0.3合金的抗CO毒化性能,进行了动力学性能测试、循环次数测试等.实验结果表明,化学镀Pd后的贮氢合金与未镀Pd的合金相比,吸氢性能得到改善,表现为 平台区域相对变平,吸氢孕育期缩短、循环次数增加,抗CO毒化性能提高.