Route Maintenance in IEEE 802.11 wireless mesh networks

In this paper, we propose a novel Route Maintenance scheme for IEEE 802.11 wireless mesh networks. Despite lack of mobility and energy constraints, reactive routing protocols such as AODV and DSR suffer from frequent route breakages in 802.11 based infrastructure wireless mesh networks. In these networks, if any intermediate node fails to successfully transmit a packet to the next hop node after a certain number of retransmissions, the link layer reports a transmission problem to the network layer. Reactive routing protocols systematically consider this as a link breakage (and therefore a route breakage). Transmission failures can be caused by a number of factors e.g. interference or noise and can be transient in nature. Frequent route breakages result in significant performance degradation. The proposed mechanism considers multiple factors to differentiate between links with transient transmission problems from those links which have permanent transmission problems and takes a coherent decision on link breakage. The proposed mechanism is implemented in AODV for single-radio single-channel mesh network and an extension is incorporated in multi-radio multi-channel scenarios. Simulation results show substantial performance improvement compared to classical AODV and local route repair schemes.     

浅谈高校中的计算机安全管理

随着因特网的普及和发展,高校的计算机安全面临着许多恶意的代码和黑客的攻击,致使高校的计算机网络室安全管理软件和还原软件全部失效,但高校计算机安全性太高又不利于学生对计算机的使用。本文主要介绍了利用注册表实现高校电子阅览室计算机安全管理的实例,以便更深入的对计算机安全管理的了解。     

An experiment on the role of graphical elements in architecture visualization

The evolution and maintenance of large-scale software systems requires first an understanding of its architecture before delving into lower-level details. Tools facilitating the architecture comprehension tasks by visualization provide different sets of configurable, graphical elements to present information to their users. We conducted a controlled experiment that exemplifies the critical role of such graphical elements when aiming at understanding the architecture. In our setting, a different configuration of graphical elements had significant influence on program comprehension tasks. In particular, a 63% gain in effectiveness in architectural analysis tasks was achieved simply by changing the configuration of the graphical elements of the same tool. Based on the results, we claim that significant effort should be spent on the configuration of architecture visualization tools and that configurability should be a requirement for such tools.

《计算机维护技术》课程教学改革的研究

坚持不懈地推进教学改革工作,注重理论与实践相结合的教学方法,通过对《计算机维护技术》课程的教学改革来提高学生的技术水平与实践操作能力,从而培养真正的高级应用型人才,是当前高校教育领域值得深入研究的问题。     

A multi-agent intelligent system for efficient ERP maintenance

The Enterprise Resource Planning (ERP) system is an enterprise-wide integrated software package designed to uphold the highest quality standards of business process. However, for the time being, when the business condition has been changed, the system may not guarantee that the process embedded in ERP is still best. Moreover, since the ERP system is very complex, maintaining the system by trial and error is very costly. Hence, this paper aims to construct a support system that adjusts ERP system to environmental changes. To do so, we adopt multi-agent intelligent technology that enables autonomous cooperation with one another to monitor ERP databases and to find any exceptional changes and then analyze how the changes will affect ERP performance. Moreover, Petri net is applied to manage the complexity and dynamics of agents’ behavior. To show the feasibility of the idea, a prototype agent system, ERP/PN, is proposed and an experiment is conducted.     

基于加卸载响应比理论的大坝台风作用效应计算方法

台风对大坝的作用包括台风引起的强降雨对大坝的影响、台风引起的库水位波动(波浪)对大坝的影响以及台风风荷载对大坝的影响等。基于加卸载响应比理论,通过对台风作用下的大坝效应增强和维持判据进行深入研究,提出了库水位加卸载响应比和波浪加卸载响应比的计算方法,给出了台风作用下大坝效应增强与维持判据的评判准则。利用上述方法和评价准则,对受2010年10号台风"莫兰蒂"影响的东坞水库进行分析,结果表明,东坞水库大坝受台风影响不大,大坝处于稳定状态。将加卸载响应比理论引入到水利工程领域,是对加卸载响应比理论的应用范围的拓展,也是研究台风作用下大坝稳定性的新思路。     

浅谈多媒体教室设备管理与维护

随着多媒体技术在高校的普及,多媒体教室需求也急剧上升,由此多媒体教室设备的安全问题、多媒体教室的设备操作问题、多媒体教室的管理模式问题、多媒体设备故障处理问题等也应运而生。本文就多媒体教室设备的管理和维护中存在的问题展开分析并提出解决问题的方法。     

八面河油田油润滑防偏磨工艺研究与现场应用

八面河油田目前主要是采用传统的油井防偏磨工艺,而在高含水的井液中易导致杆、管偏磨机率增加,随着含水率的上升,偏磨失效井次也相应上升。所以,应在传统的油井防偏磨工艺的基础上,结合实际情况应用新技术。而空心杆油润滑防偏磨工艺的技术可以对油井偏磨防治起到一定效果。     

网站运行维护之我见

网站的正常运行离不开网管人员的日常维护工作.清河采油厂网站是一个专业性强、复杂性强的综合性网站.为了更好地加强该网站的维护工作,对网站的环境安全、信息安全、病毒防范、网站优化等问题做了认真分析,并指出了今后网站的维护工作要点:1)日常维护要做到位;2)养成分析日志习惯;3)健全落实网站制度.     

一台220kV电容式电压互感器的故障分析

通过一台电容式电压互感器的故障分析，提出对电容式电压互感器的维护以及预防性试验的一些看法。