VPN 系统反馈调整和实时监控集成解决方案

传统VPN系统存在不能根据状态自动调整运行,而且缺乏对运行状态的监控的问题,为此以Open VPN为基础,提出一个VPN系统自动管理和实时监控解决方案,通过编写程序分析和理解服务运行状态,根据反馈触发执行相应管理程序,与管理端口进行通信调整服务行为,同时使用SNMP协议构造监控代理程序,对系统性能进行实时监控,使得管理员能够通过Cacti监控平台实时了解系统运行参数,达到保障VPN服务持续可靠和高效运行的目的。实验结果表明,该系统能够根据当前状态所设定的规则优化运行,并为管理员提供直观实时的性能视图。     

基于CACTI的分布式ORACLE监控系统的设计与实现

针对多个ORACLE数据库系统的主动性监控问题,提出一个基于CACTI的分布式监控报警系统。采用＂一个管理端＋多个代理＂的监控模式,CACTI作为监控管理端,在运行ORACLE数据库服务器上添加代理模块,实现对物理位置上分布的多个ORACLE进行不间断的集中式监控。通过在CACTI上对各个ORACLE数据库设置不同的性能报警粒度,实现系统多层次多粒度、灵活多样的监控策略,并对数据库运行过程中的异常状态进行邮件和短信报警。实验结果和型号项目中的实际应用验证了系统的有效性。     

磁盘阵列控制软件设计及其实时响应分析

作为一种海量存储设备,磁盘阵列在当前获得了广泛的应用.本文介绍了一种基于实时嵌入式系统VxWorks的磁盘阵列控制软件的体系结构及其各模块的功能,并分析了该系统的实时响应能力.     

数码监控系统磁盘阵列的扩展及数据优化管理

近年来,数码相机监控系统以其高分辨率、方便、快捷、处理软件丰富以及高性能比等优点,愈来愈受到人们的关注。但是该系统仍然存在着一系列有待继续研究的问题,比如存储数据量大、不易管理等。针对以上不足,在介绍数码相机监控系统软、硬件的设计和开发过程同时,着重讨论数码相机监控系统磁盘阵列存储系统的扩展和图像采集数据的管理等问题。     

基于SNMP网络实时监控技术的研究

本文讨论了一种运用ＳＮＭＰ协议对网络实时监控的方法，并介绍了一种我们已经实现的网络实时监控系统的特点。     

通用性机房集中监控系统的设计与实现

为了解决企业中心机房监控环境与受控设备易变性问题,通过研究计算机、自动控制、通信等技术,实现了多变监控环境下的通用性集中监控系统。基于组态技术设计了图形组态子系统,采用图形定制方式实现机房监控的通用性。采用模块化思想建立系统结构模型,完成机房设备的数据采集、显示及报警联动处理,并可在不影响监控运行前提下完成配置更新,快速适应机房环境的改变。通过系统的部署使用,表明了集中监控系统的可靠性,保证了多变环境下机房设备的稳定运行。     

CACTI和QQVIEW在网络监控中的应用分析

本文主要阐述了如何利用网络监控软件CACTI和QQVIEW的统计分析功能．强化网络运维管理。同时通过在内部网络中及时发现并处理问题和隐患,来预警和保障网络的整体稳定运行。     

报警采集与DVR监控联动解决方案

目前在大量的工程中。安保单位要求将报警信号传输到总控中心的同时能够显示报警点，并可以对中心的录像监控系统进行联动。由于实际现场的技术问题比较复杂，工程商往往面临多家探测器．哪产品的选择和匹配问题。     

刍议CACTI和QQVIEW在网络监控中的实践

本文从如何强化网络监控入手,探讨当前CACTI和QQVIEW在网络监控中的应用,以及通过CACTI和QQVIEW如何发现和处理问题,从而提高网络运行的稳定性。     

校园网网络流量监控系统的研究与实现

网络流量监测是网络性能分析和通信网络规划设计的基础,分析了SNMP模式网络流量采集技术,并利用PHP语言结合RRDTOOL、CACTI等加以实现,通过HTTP协议实现了客户端用户交互,最终生成实时的PNG格式流量图,给网络的正常运行网络管理维护工作带来极大的方便。     

Universal Timestamp-Scheduling for real-time networks

Consider a network of computers interconnected by point-to-point communication channels. For each flow of packets through the network, the network reserves a fraction of the packet rate of each channel along the path of the flow. We define a family of scheduling protocols, called Universal Timestamp-Scheduling, to forward packets in this network, such that all members of the protocol family provide the same upper bound on packet delay as the well-known packet delay of Virtual Clock scheduling. The protocol family is called universal because it encompasses a wide variety of protocols. To show this, we prove that many scheduling protocols in the literature are members of the protocol family, and thus provide the above guarantee. In addition, we show that the protocols in the literature have only considered one side of the spectrum of possible scheduling protocols, and that there is another side of the spectrum that deserves attention and remains to be investigated.     

基于实时监控的计算机安全解决方法

随着科技的发展,计算机技术也在我国迅速发展起来,随着计算机技术的不断普及和发展,计算机产品的系统安全也成为人们所关注的问题.如何实现计算机产品和技术的系统的安全性成为人们研究的重要内容,本文根据BIOS原理以及USBkey技术特点介绍了一种基于实时监控的计算机安全解决方法,以期对计算机的系统安全提供参考性意见.     

Energy management for a real-time shared disk cluster

Energy management for cluster architectures has become an important design issue. In this paper, we propose a dynamic reconfiguration algorithm, named DRA-SD, to reduce the energy consumption of a real-time shared disk (SD) cluster. DRA-SD consolidates cluster load on a subset of nodes if the quality of service (QoS) is met. Remaining nodes are deactivated so that they can stay at a low-power state. When the load increases again, DRA-SD dynamically activates additional nodes. Unlike previous algorithms proposed for web server clusters, DRA-SD exploits the inherent characteristics of SD cluster to reduce the internode interference and to improve the processing capacity of a given cluster configuration. This enables DRA-SD to meet the QoS constraint while consuming minimal energy. Experiment results show that DRA-SD can save energy significantly under a wide variety of transaction workloads and node characteristics.     

Energy-aware disk scheduling for soft real-time I/O requests

In this work, we develop energy-aware disk scheduling algorithm for soft real-time I/O. Energy consumption is one of the major factors which bar the adoption of hard disk in mobile environment. Heat dissipation of large scale storage system also calls for an energy-aware scheduling technique to further increase the storage density. The basic idea in this work is to properly determine the I/O burst size so that device can be in standby mode between consecutive I/O bursts and that it can satisfy the soft real-time requirement. We develop an elaborate model which incorporates the energy consumption characteristics, overhead of mode transition in determining the appropriate I/O burst size and the respective disk operating schedule. Efficacy of energy-aware disk scheduling algorithm greatly relies on not only disk scheduling algorithm itself but also various operating system and device firmware related concerns. It is crucial that the various operating system level and device level features need to be properly addressed within disk scheduling framework. Our energy-aware disk scheduling algorithm successfully addresses a number of outstanding issues. First, we examine the effect of OS and hard disk firmware level prefetch policy and incorporate its effect in our disk scheduling framework. Second, our energy aware scheduling framework can allocate a certain fraction of disk bandwidth to handle sporadically arriving non real-time I/O’s. Third, we examine the relationship between lock granularity of the buffer management and energy consumption. We develop a prototype software with energy-aware scheduling algorithm. In our experiment, proposed algorithm can reduce the energy consumption to one fourth if we use energy-aware disk scheduling algorithm. However, energy-aware disk scheduling algorithm increases buffer requirement significantly, e.g., from 4 to 140 KByte. We carefully argue that the buffer overhead is still justifiable given the cost of DRAM chip and importance of energy management in modern mobile devices. The result of our work not only provides the energy efficient scheduling algorithm but also provides an important guideline in capacity planning of future energy efficient mobile devices. This paper is funded by KOSEF through Statistical Research Paper for Complex System at Seoul National University.     

实时多媒体服务端到端QoS解决方案

区分服务（Diif-Serv）模型其主要是通过实时多媒体通信数据包进行分类和策略控制来达到调节网络资源的目的,从而实现对实时多媒体服务端到端服务质量QoS。如何时多媒体网络系统中的不同的信息流进行正确的区分服务．然后对不同类别采取不同的服务策略和拥塞管理,从而对网络资源进行有效配置,是实现实时多媒体服务端到端服务质量QoS的关键步骤。文章重点对实时多媒体信息如何进行分类及相应的服务策略和拥塞管理进行时比研究,提出实现端到端QoS服务质量的具体措施和解决方案。并在Cisco思科路由器和交换机建立的DiffSeFV网络环境中进行验证,实验结果表明。对实时多媒体信息进行合理的分类及采用相应服务策略．能很好地实现实时多媒体信息流端到端的服务质量QoS。最后阐述了Diffsenr区分服务存在的问题和未来的发展趋势。     

Task behavior monitoring for adaptive real-time communication

Real-time distributed systems include communicating tasks that interact via message-passing. In such systems the timely delivery of messages is essential for meeting task timing constraints. Consequently, in addition to task execution times, message delivery times must also be constrained. In order to minimize the number of failures to meet timing constraints message communication protocols, in addition to task scheduling algorithms, play a crucial role. A legitimate question to ask is whether making such protocols adaptive to run-time system and environment status can significantly improve system performance. Consequently, a rum-time monitoring approach to adaptive real-time distributed systems is proposed; the work focuses on an investigation of adaptive message communication protocols and corresponding run-time support mechanisms. Simulation is used to obtain performance results. It is concluded that although improvement is obtained it ,ay not be significant enough to offset the increased overhead and requirement for task information.     

高端磁盘阵列马尔科夫过程可靠性模型研究

介绍了基于马尔科夫过程的磁盘阵列典型模型,分析了典型模型中存在的不足。依照海量存储系统中磁盘阵列工作的特点,结合蒙特卡罗方法,引入新的状态和参数,对基于马尔科夫过程的磁盘阵列可靠性计算模型进行改进,使可靠性数值更接近实际情况。     

A robust strategy for real-time process monitoring

An operator support system (OSS) is proposed to reliably retain salient information in a high dimensional and correlated database, to uncover linear and nonlinear correlations among variables, to reconstruct failed/unavailable sensors, and to assess process-operating performance in the presence of noise and outliers. The proposed strategy carries out the task in three steps. In the first step, a robust tandem filter is used to suppress noise and reject any outlying observations. Next, an orthogonal nonlinear principal component analysis network is utilized to optimally retain a parsimonious representation of the system. In the final step, the process status is checked against the normal operating region defined by kernel density estimation, and failed/unavailable sensors are reconstructed via constrained optimization and the trained network. The strategy is demonstrated in real-time using a pilot-scale distillation column.     

Performance evaluation of two new disk scheduling algorithms for real-time systems

In this paper, we present two new disk scheduling algorithms for real-time systems. The two algorithms, called SSEDO (Shortest Seek and Earliest Deadline by Ordering) and SSEDV (Shortest Seek and Earliest Deadline by Value), combine deadline information and disk service time information in different ways. The basic idea behind these new algorithms is to give the disk I/O request with the earliest deadline a high priority, but if a request with a larger deadline is very close to the current disk arm position, then it may be assigned the highest priority. The performance of the SSEDO and SSEDV algorithms is compared with three other proposed real-time disk scheduling algorithms ED, P-SCAN, and FD-SCAN, as well as four conventional algorithms SSTF, SCAN, C-SCAN, and FCFS. An important aspect of the performance study is that the evaluation is not done in isolation with respect to the disk, but as part of an integrated collection of protocols necessary to support a real-time transaction system. The transaction system model is validated on an actual real-time transaction system testbed, called RT-CARAT. The performance results show that SSEDV outperforms SSEDO; that both of these new algorithms can improve performance of up to 38% over previously-known real-time disk scheduling algorithms; and that all of these real-time scheduling algorithms are significantly better than nonreal-time algorithms in the sense of minimizing the transaction loss ratio.This work is supported, in part, by the Office of Naval Research under contract N00014-87-K-796, by NSF under contract IRI-8908693, and by an NSF equipment grant CERDCR 8500332.