山西防汛抗旱指挥部一体化机房解决方案

由于防汛抗旱指挥部工作的特殊性，因此在机房布设方面，要求整个机房的运行必须高度稳定、可靠，以保障数据的安全，以及整个系统7×24小时不间断运行。     

基于PLC的煤气计量系统

本文介绍一种基于PLC的煤气计量系统。以昆明市煤气计量站的煤气计量系统为例,阐述了该系统的体系结构。该系统采用主、备份机同时运行的方式,保证数据采集的不间断。系统实际运行稳定、数据采集准确。     

两种重要的热插拔技术

在服务器领域，系统运行的稳定性和可靠性是非常重要的。人们希望服务器24×365不间断运行，以便给商业网站、电信系统、银行系统等提供“永远在线”的服务。     

供水工程自动化控制系统设计

针对V型滤池净水处理工艺,设计了以冗余PLC为现场控制站、工控机为监控管理机的全厂计算机监控系统.本控制系统将工控机、PLC、变频器、传感器和执行机构有机地结合起来,发挥各自优势,软件设计合理,系统调试较方便;且系统各级之间可独立运行,保证了水厂的不间断生产.     

完备冷冗余FDCS系统的设计与实现

本文介绍了一种已用于实际的完备冷冗余FDCS系统;监控器降级重构解决了双单元冗余的可靠性瓶颈问题;介绍了故障诊断原理及上位机冗余技术该系统现已以每24h不间断运行了2年,达到了可靠性设计要求。     

UPS在综合电厂的应用

以山西西山热电有限责任公司的交流不间断电源系统为例,交流不间断电源系统为电厂自动化系统、消防安全报警装置等重要负荷提供稳定的、可靠的不间断电源,在电厂有着重要的作用.     

DMHS-H转报机业务不中断搬迁解决方案

在民航空管系统通信基础设备中自动转报系统起着举足轻重的作用,它是保证民用航空安全和飞行正常必不可少的手段。本文已DMHS-H 96路转报机为例,以不间断系统运行为目的,结合实际经验,介绍了DMHS-H 96路大型转报机搬迁过程。     

小议UPS不间断电源的原理及维护保养

本文简要介绍了UPS不间断电源系统的工作原理、系统维护以及运行中应该注意的关键事项,从而有助于在工作中提升UPS不间断电源系统的使用寿命以及使其更具有可靠性的稳定。     

详解地铁清分系统

广州地铁自动售检票系统及其清分系统在实际运行中情况良好,系统达到了不间断工作的目标,为广州地铁的整个AFC系统提供持续稳定的服务。     

软件实时可信度量:一种无干扰行为可信性分析方法

可信度量作为可信计算"度量、存储、报告"三大核心功能的基础，到目前为止仍未有有效的数学理论以及运行时（runtime）度量方法.其困难在于3点：一是如何建立涵盖不同主流"可信"定义的通用数学模型；二是如何依托数学模型构建运行时可信度量理论；三是如何将上述模型和理论映射到真实信息系统以形成可实践的实时度量方法.提出了一种基于无干扰的软件实时可信度量方法.首先，利用无干扰模型解释了各类主流的可信定义，表明无干扰模型可以作为可信计算通用数学模型的一个选择.其次，基于无干扰模型提出了一种软件实时可信度量理论，其基本思想是将系统调用视作原子动作，将软件真实行为α看做系统调用的序列，并基于α中所有系统调用所属安全域之间的无干扰关系计算软件理论上的预期行为β，得到α和β之后，利用无干扰等式判定两者之间是否存在偏差，从而实现对软件可信性的实时度量.最后，给出了实时可信度量算法，算法的时间复杂性为O（1）.原型实验结果表明了所提出的方法的有效性.     

对现代操作系统的思考

当前,高等院校的操作系统教学过程主要是基于传统的操作系统基本原理而进行的,与现代操作系统的发展不相适应,在教学过程中很难让学生理解当前操作系统发展的挑战和今后的发展方向。本文对现代操作系统的特性进行分析,阐述其在教学过程中的必要性和重要性,并介绍使用微软公司的Singularity项目进行操作系统教学的经验。实践表明,Singularity系统架构清晰简洁,很好地体现了现代操作系统的理念,适用于高等院校的操作系统教学。     

基于自律计算的系统可信性自调节模型

保障和增强系统的可靠性、安全性和稳定性等可信性质是对系统服务的高级要求。提出了一个基于自律计算理念的系统可信性自调节模型,该模型动态分析目标系统的可信度变化趋势,参考先验可信度变化曲线的梯度升降,依序实现可信度在线评估、可信度动态预测和自调节方案选择,完成系统可信度非降的自主调节过程,采用信赖域梯度计算策略解决自调节的最优化问题。     

An evaluation model for dependability of Internet-scale software on basis of Bayesian Networks and trustworthiness

Internet-scale software becomes more and more important as a mode to construct software systems when Internet is developing rapidly. Internet-scale software comprises a set of widely distributed software entities which are running in open, dynamic and uncontrollable Internet environment. There are several aspects impacting dependability of Internet-scale software, such as technical, organizational, decisional and human aspects. It is very important to evaluate dependability of Internet-scale software by integrating all the aspects and analyzing system architecture from the most foundational elements. However, it is lack of such an evaluation model. An evaluation model of dependability for Internet-scale software on the basis of Bayesian Networks is proposed in this paper. The structure of Internet-scale software is analyzed. An evaluating system of dependability for Internet-scale software is established. It includes static metrics, dynamic metrics, prior metrics and correction metrics. A process of trust attenuation based on assessment is proposed to integrate subjective trust factors and objective dependability factors which impact on system quality. In this paper, a Bayesian Network is build according to the structure analysis. A bottom-up method that use Bayesian reasoning to analyses and calculate entity dependability and integration dependability layer by layer is described. A unified dependability of the whole system is worked out and is corrected by objective data. The analysis of experiment in a real system proves that the model in this paper is capable of evaluating the dependability of Internet-scale software clearly and objectively. Moreover, it offers effective help to the design, development, deployment and assessment of Internet-scale software.     

Mercury: Combining Performance with Dependability Using Self-Virtualization

Virtualization has recently gained popularity largely due to its promise in increasing utilization,improving availability and enhancing security.Very often,the role of computer systems needs to change ...     

计算机系统开发中的可信性评价概述

本文将高可信计算机系统的开发过程划分为需求，设计，实现和集成四个阶段，分别介绍各阶段中与可信性有关的任务及可信性评价技术的应用。     

N路冗余重路由算法及其性能分析

通过分析基于重路由的匿名通信系统模型,提出一种适合节点在环境恶劣、性能不稳定条件下工作的N路冗余重路由算法,对使用该算法的匿名通信系统的可靠性、负载特性和匿名性进行理论推导和分析,结果证明,该算法能满足用户提出的可靠性边界条件,较大地提高重路由路径的可靠性并保证系统的匿名性,但会增加节点负载,减小系统容量。     

Analyzing User-Perceived Dependability and Performance Characteristics of Voting Algorithms for Managing Replicated Data

User-perceived dependability and performance metrics are very different from conventional ones in that the dependability and performance properties must be assessed from the perspective of users accessing the system. In this paper, we develop techniques based on stochastic Petri nets (SPN) to analyze user-perceived dependability and performance properties of quorum-based algorithms for managing replicated data. A feature of the techniques developed in the paper is that no assumption is made regarding the interconnection topology, the number of replicas, or the quorum definition used by the replicated system, thus making it applicable to a wide class of quorum-based algorithms. We illustrate this technique by comparing conventional and user-perceived metrics in majority voting algorithms. Our analysis shows that when the user-perceiveness is taken into consideration, the effect of increasing the network connectivity and number of replicas on the availability and dependability properties perceived by users is very different from that under conventional metrics. Thus, unlike conventional metrics, user-perceived metrics allow a tradeoff to be exploited between the hardware invested, i.e., higher network connectivity and number of replicas, and the performance and dependability properties perceived by users.     

A unified model of dependability: capturing dependability in context

In contemporary societies, individuals and organizations increasingly depend on services delivered by sophisticated software-intensive systems to achieve personal and business goals. So, a system must have engineered and guaranteed dependability, regardless of continuous, rapid, and unpredictable technological and context changes. The International Federation for Information Processing Working Group defines dependability as "the trustworthiness" of a computing system, which allows reliance to be justifiably placed on the services it deliver.     

多进程内存利用率自动监视分析技术的研究及实现

为了保证应用程序,特别是自动监控系统等需要长期运行的程序的可靠性、稳定性,提出了一种在软件产品生产测试阶段,能及时自动测试监控程序的内存及CPU负荷率等关键性能指标的方案,及其在某变电站监控系统测试中的实际应用。     

旋流器组粒度分级原理及粒度控制技术

探索选矿厂的磨矿－ 分级过程的工作机理。并重点探讨旋流器组的粒度分级原理及粒度控制技术的实施方法。把旋流器组作为１ 个集工艺操作、过程检测控制及机电设备启停为一体的综合自动化控制系统。提出集散系统为基础的旋流器组控制系统的设计原理及系统构成。