VxWorks多任务网络实时处理软件设计

VxWorks是一种嵌入式实时多任务操作系统,广泛应用于航空航天、通信电子、物联网等领域.多任务软件设计的合理性对嵌入式系统软件的稳定性、可靠性起着重要的作用.对VxWorks网络通信机制以及多任务调度机制进行了分析,介绍了多任务实时软件设计过程中涉及到的任务划分、任务优先级的设置、堆栈大小设置、任务释放等关键问题,结合应用实例给出多任务通信软件设计的步骤和方法,通过试验验证了设计的合理性和可靠性,为基于VxWorks多任务实时处理软件的设计提供了一定的参考.     

双模机顶盒的软件研究与设计

给出一种基于VxWorks嵌入式操作系统的双模机顶盒的软件实现,能够同时支持数字电视和高速IP数据接入业务.重点分析了软件系统的规划和设计,以及主应用任务创建的具体流程.     

基于网络处理器的VxWorks高层协议栈开发

主要介绍如何在运行VxWorks操作系统的IXP1200网络处理器上开发网络层协议栈驱动程序和VxWorks的基本情况,然后介绍VxWorks中网络层驱动与MUX接口和END驱动之间的关系,并分析伪以太网驱动程序的工作原理,讨论了网络处理器微引擎程序的设计与实现方法.     

基于VxWorks的某监控中心通信任务的设计与实现

本文介绍了基于 VxWorks 的某监控中心通信任务的设计与实现,重点阐述了在该系统通信协议的框架下如何实现串口通信功能以及任务间的通信机制在设计中的具体应用。     

基于VxWorks的DM9000网卡驱动

随着嵌入式操作系统VxWorks的广泛应用,如何让VxWorks支持各种硬件平台成了急需解决的问题。首先介绍大幅面扫描仪的发展趋势以及嵌入式操作系统VxWorks的优势。然后通过分析VxWorks的SENS协议栈;VxWorks下END网络驱动程序的结构;S3C2440A板载DM9000网卡的硬件特性和操作特点,实现基于VxWorks的DM9000 END驱动程序。最后修改相应bsp,使S3C2440A可以跨平台通信。     

基于VxWorks增强型网络驱动开发的研究

介绍了在VxWorks系统下开发增强型网络驱动的基本方法。首先介绍了需要用到相关基本数据结构;然后重点分析了VxWorks加载初始化驱动的过程,深入探讨了如何开发相应的驱动程序;最后介绍了VxWorks网络协议栈所要求数据帧封装的格式。文章将开发增强型网络驱动程序的方法做了研究和总结,方便开发者较快开发出相应的驱动程序。     

基于VxWorks的双485口通信系统设计

VxWorks嵌入式操作系统具有高效的实时任务管理与调度、任务的同步与通信、内存管理、I/O管理、时钟管理等机制.两个485口在通信速率、工作模式、控制方式上有较大差别且系统死线要求严格.详细介绍了VxWorks下双485口串行通信系统BSP、驱动程序和应用程序的开发过程.基于VxWorks构建的嵌入式串行通信系统实时性好,效率高,可根据硬件进行优化配置;利用VxWorks的I/O系统将驱动程序作为内核过程,设备作为特殊文件处理,解决了工作方式不同的两个485 口的驱动程序开发和接口统一问题.     

基于VxWorks的飞机配电自动化主执行软件研究

本文探讨了在嵌入式实时操作系统(RTOS)VxWorks下开发电源系统处理机主执行软件的过程,介绍了嵌入式实时操作系统VxWorks的特性。对PSP主执行软件的设计做出了分析,并介绍了如何在嵌入式实时操作系统下实现。     

基于VxWorks的飞机配电自动化主执行软件研究

本文探讨了在嵌入式实时操作系统(RTOS)VxWorks下开发电源系统处理机主执行软件的过程,介绍了嵌入式实时操作系统VxWorks的特性.对PSP主执行软件的设计做出了分析,并介绍了如何在嵌入式实时操作系统下实现.     

VxWorks操作系统在S3C4510B上的移植

VxWorks是一种支持多种体系结构处理器的操作系统，有很强的移植性。描述了将VxWorks移植到基于S3CA510B处理器目标板上的方法与过程。首先介绍了VxWorks和板级支持包BSP的概念并分析了VxWorks的启动过程和S3CA510B处理器，并简单说明了将如何搭建移植环境，然后着重讨论了在该开发板上BSP的设计实现以及VxWorks的移植方法。     

Multimethod approaches for the study of computer-mediatedcommunication, equivocality, and media selection

This paper presents a longitudinal case study of the introduction of voice mail, applying media richness theory to develop and assess a set of 16 tasks with varying levels of equivocality, and to compare different media. Through t-tests, reliability, factor, and multidimensional scaling analyses, evaluation of task equivocality and voice mail is discussed and potential shortcomings of current approaches are highlighted. Results show that equivocality does not seem to be unidimensional and includes aspects of authority across organizational boundaries. Across all tasks, telephone would be most likely selected by respondents, but face-to-face and telephone were more likely to be selected for more equivocal tasks. Unlike prior studies, voice mail is perceived as similar to documents and face-to-face     

VistaMail: an integrated multimedia mailing system

VistaMail, a fully integrated multimedia mailing system, lets users easily create, send, and view audio and video components. The system treats these components as part of a single unified message rather than as additions to the text portion. This article discusses the design of the multimedia mail system and some of the issues involved in implementing it     

Can't we all just get along?

Now the push is on to move beyond simply exchanging data and to allow software applications to employ other applications in the same way that a person might use multiple programs to achieve a task. For example, a person has no problem using a Web browser to download an image, another program to sharpen the image, and finally an e-mail program to send the image to someone else. This effort to expose functionality has ultimately resulted in plans to create so-called Web services These plans originated as companies tried to figure out distributed computing, which spreads heavy computational tasks over multiple computers in a network and yet makes the results appear to the end user as if they were the product of running an application on a single, superpowerful machine.     

基于XMPP协议的移动即时通信邮件网关设计

针对当前移动即时通信软件仅局限于提供即时聊天等简单功能的现状,设计了一个基于开放、标准的XMPP协议的邮件协议转换网关。通过在移动即时通信服务器上增加邮件网关处理子模块进行相应协议的转换,实现移动即时通信终端与邮件服务器的良好对接,使得终端用户可以像在PC机上一样简单方便地收发邮件,扩展了移动即时通信系统的功能应用。     

The communication characteristics of virtual teams: a case study

Organizations are encountering novel external environments requiring flexible structures. A number of organizations have used virtual teams to provide the customer responsiveness, human resource flexibility, and speed in project completion these environments demand. Virtual teams create significant communication challenges for its leaders and members. This research analyzed the communication technologies that the Customer Support Virtual Team (CST) of International Consulting Systems (ICS), the pseudonym for a Fortune 500 organization, uses to support team interaction, the degree to which ICS systems and culture supported CST, and finally, the CST members' mindset toward communication and the methods its leader used to create the trust required for effective team interaction. Interviews revealed that ICS mission, strategy, tasks, reward systems, and attitudes toward technology supported virtual team structure. CST members were provided a suite of robust technologies to facilitate interaction; however, they relied heavily on voice mail and a large number of team, project, and organizational databases supported by Lotus Notes to generate a common language that facilitated task completion     

怎样评判优秀的大容量电子邮件系统

在中国，邮件服务已是各ISP、综合性网站和专业性网站的必备项目，收发邮件已成为中国网民上网的首要理由。大容量支持且高效、可靠的邮件系统应具有的标准主要有：安全性和垃圾邮件的防范、可靠性、高效灵活、可扩展性、用户的自我管理和测试及售后支持等。     

Task based kinematic design of a two DOF manipulator with a parallelogram five-bar link mechanism

As the demand for modular manipulators or special purpose manipulators has increased, task based design to design an optimal manipulator for given tasks become more and more important. However, manipulator design problems usually are very complex due to a large number of design parameters, their nonlinear and implicit relationship, and so on. To achieve task based design successfully, it is necessary to develop a methodology that can solve the complexity. This paper addresses how to determine the kinematic parameters of a two degrees of freedom manipulator with a parallelogram five-bar link mechanism from a given task, namely, how to map a given task into the kinematic parameters. With a simplified example of designing a manipulator with a five-bar link mechanism, a methodology for task based design is presented. And it introduces formulations of task specifications and manipulator specifications, and presents a new dexterity measure as an optimality criterion for manipulator design. Also it finds out an optimal design solution for the manipulator by using a genetic algorithm that has robust search performance in complex spaces.     

Analysis and modeling of task scheduling in wireless sensor network based on divisible load theory

In this paper, we propose a novel task scheduling algorithm (Divisible Task scheduling Algorithm for Wireless sensor networks (DTAW)) based on divisible load theory in heterogeneous wireless sensor networks to complete the tasks within the shortest possible time and reduce the sensors' energy‐consuming. In DTAW, the tasks are distributed to the wireless sensor network by the (SINK) on the basis of the processing and communication capacity of each sensor. After receiving the subtasks, the intracluster sensors carry out its tasks simultaneously and send the results to cluster head sequentially. By removing communication interference between each sensor, reduced task completion time and improved network resource utilization are achieved. Each cluster head simultaneously finishes sending fused data to the SINK after fusing the data obtained from intracluster sensors. In this way, the overlap between the task performing and communication phase would be much better. Simulation results are presented to demonstrate the impacts of different network parameters on the makespan and energy consumption. The results show that the algorithm enables to reasonably distribute tasks to each sensor and then effectively reduces the time‐consuming and energy‐consuming. Copyright © 2012 John Wiley & Sons, Ltd.     

一种扩展的TBAC访问控制模型研究

基于任务访问控制模型(TBAC)与传统的访问控制模型不同,它不是将访问许可与角色或用户联系起来,而是将许可与任务联系。本文在基于任务的访问控制对象建模的基础上,为使不同的异质的工作流系统下的任务可以安全地迁移,授权的紧密性得到保证,引入了授权单元的概念,并在工作流系统中讨论了授权单元的应用,将授权与工作流紧密结合,强调上下文联系,最后就实际解决TBAC模型中存在的授权原子性和事件触发等问题讨论了解决方案。     

WSN中基于强化学习的能效优化任务处理机制

以提高无线传感器网络中任务处理的能效为目标,提出了一种近似最优化的任务处理机制,无线传感器节点可根据任务缓存区的任务数量、信道条件,动态地实现任务向边缘服务器的卸载以及本地处理.将任务处理机制建模为马尔可夫决策过程,因为无线传感器节点不知道此过程的状态转移概率,所以采用A3C算法以实现在环境参数未知情况下的探索和学习,...