振动传感器的原理选择

介绍了几种类型的振动传感器的工作原理,如电阻应变式、电感式、电容式、压电式、霍尔式、磁电式振动传感器.为了选择更为合适的某种原理的传感器,对比了相对式、惯性式振动传感器的不同,并指出在物理量的转换过程中,惯性式传感器存在的明显缺点一难以保证信号的不失真传递.得出了结论,在传感器原理选择的时候首选相对式振动传感器,并介绍了相对式振动传感器的主要分类,包括电感式位移传感器、电容式位移传感器、磁电式速度传感器.     

可配置网络式软件系统的可用性预计研究

在复杂系统的建模与仿真研究的基础上,提出了一种基于多Agent的可配置网络式软件系统的可用性预计方法。首先介绍了多Agent系统建模与仿真方法;其次分析了可配置网络式软件系统的特点;然后在研究基于多Agent的网络式软件系统建模与仿真的基础上,研究可配置的行为模型,并建立了基于多Agent的可配置网络式软件 系统可用性仿真方法;最后利用Nctlog。仿真平台,结合实例对可配置的作用进行了可用性预计,并验证了本方法的有效性。     

基于Agent和带权关系网的软件体系结构自适应

作为软件的蓝图,描述整个系统的结构和行为模型的软件体系结构在软件自适应中起着重要作用,具有适应性特征的Agent为构造自适应软件系统提供了独特的优势.针对现有基于Agent的软件系统在体系结构和动态配置方面的不足,提出了一种基于带权关系网模型,利用Agent对环境的监测和评估,以调整Agent间联系的权重来决策Agent间的合作对象的选择,从而使得基于Agent的软件系统在构件、连接件和配置方面具备适应性,为开发基于Agent的自适应软件系统提供借鉴和参考.     

软件系统配置研究综述

随着软件系统规模和复杂度的不断提升, 软件配置已经成为软件工程领域中的一个重要话题. 大量、复杂的配置项为正确使用软件系统带来了极大的困难, 例如, 配置错误会影响系统性能, 并带来严重损失. 软件系统配置技术得到广泛关注, 并取得了众多的研究成果. 本文对软件配置领域的研究现状和主要成果进行分析和综述. 文章首先提出了基于软件生命周期和技术手段两个维度的软件配置相关工作分析框架, 然后基于该框架对当前主要研究成果进行分类总结和分析评价, 最后总结软件配置领域的工作特点, 探讨未来可能的研究热点, 对于今后该领域的深入研究具有一定借鉴意义.     

绝对式容栅测量技术浅析

数显量具在各种制造业,尤其是传统机械制造业中,正以强劲的势头替代传统的机械量具和气动量具,成为生产现场主导测量器具.容栅数显位移传感技术和产品以其结构简单、对使用环境要求不高、测量速度快、能耗低等优点得到最为广泛的应用.介绍了相对式容栅数显量具的传感器结构、测量原理和相应的电路结构,指出相对式容栅测量系统使用过程中存在的问题,比较了绝对式容栅和相对式容栅的优缺点.介绍了绝对式容栅传感器和电路的结构,最后指出了国外绝对式容栅技术现状,以及国内绝对式容栅技术存在的差距.     

基于信息量的动态软件网络节点重要性研究

以复杂网络理论研究了面向对象软件系统质量的度量方法.以实际软件系统作为研究对象,分析了软件系统在初始化以及功能执行完全两个不同阶段下系统复杂度的变化.在此基础上,使用网络模型中节点的信息量作为评判类在软件系统中重要性的指标,用来发掘软件系统运行过程中功能上更加重要的类;最后,用软件网络的信息熵衡量软件系统的复杂度.通过研究证明了以信息量作为描述类的重要程度的合理性,进一步验证了信息熵在整个软件系统复杂程度方面的作用.     

面向多核处理器的可配置缓存一致性协议设计与实现

多核处理器需要维护缓存的一致性问题.基于目录的一致性协议具有较好的扩展性、较低的延迟,应用较多.分布式目录访问带宽高、目录查询速度快、物理实现灵活.分布式 目录一致性协议设计复杂度高,验证困难,为了降低自主CPU研发和产业化的风险,提出了一种面向多核处理器的可配置分布式目录控制单元(configurable distribute directory unit,CDDU),通过微操作机制,实现动态配置缓存一致性协议.该设计增加了多核系统缓存一致性协议的灵活性与容错性,可以实现协议状态转换和协议流程的配置,能够解决由于一致性协议设计缺陷导致的功能故障,可以防止一致性协议设计不足引起的死锁.测试结果表明:设计方案展现了良好的可配置性、可扩展性,避免了死锁产生,代价是少量的性能损耗以及面积开销.主要思想在自主飞腾64核处理器中进行了实现,为确保处理器的协议正确性发挥了重要作用,同时在该芯片的多路扩展实现过程中提高了协议的鲁棒性,消除了潜在的死锁.     

构件间依赖关系的形式化图形原语描述方法

目前,基于构件的软件系统的研究越来越引起人们的重视.提出了一种基于图形的构件间依赖关系的描述方法,并对CORBA分布式应用中构件间依赖关系的描述和依赖关系的动态更新进行了较详细的分析.在CORBA上实现了一个原型,从而实现了基于CORBA的分布式应用的动态配置.     

基于Windows 2003 Server Active Directory的计算机房管理

Active Directory是Windows 2003 Server全新的目录管理方式,它是一种层次化、树状、可扩展、可伸缩的目录结构。文章通过介绍活动目录的相关知识和安装与配置,在计算机房的具体配置,应用于机房的管理中,提高管理效率。     

基于反射机制的插件系统软件设计

为了提高软件的复用性和扩展性,缩短软件开发周期,提出了一种基于反射机制的插件系统软件设计思想.该软件系统通过一个独立的配置软件,不用编译源程序,就可以定制,修改和添加软件功能.软件系统的主要思想是基于反射机制实现插件,运用观察者模式来实现插件之间数据关系的解耦,并且用XML描述和表迭插件之间的关系以及插件的属性配置.基于该软件设计思想,设计了空间环境可视化软件系统,表明了其提高软件复用性和扩展性方面的有效性.     

Using use case patterns to estimate reusability in software systems

The applicability of using use case patterns as a basis for software cost estimation in the early stages of software development is described. This required the construction of a use case patterns catalogue using a novel process. The catalogue has been analysed to estimate the potential reusability in different software applications. This has shown that 43% of system functions are generally application domain independent, whereas 57% are application domain dependent. Statistical tests showed that the level of specialisation in software systems could be as low as 20%, which supports the direction taken in this research to build a use case patterns catalogue as a basis for the development of use case based software cost estimation models.     

Modelling methods for web application verification and testing: state of the art

Models are considered an essential step in capturing different system behaviours and simplifying the analysis required to check or improve the quality of software. Verification and testing of web software requires effective modelling techniques that address the specific challenges of web applications. In this study we survey 24 different modelling methods used in web site verification and testing. Based on a short catalogue of desirable properties of web applications that require analysis, two different views of the methods are presented: a general categorization by modelling level, and a detailed comparison based on property coverage. Copyright © 2008 John Wiley & Sons, Ltd.     

Experimental evaluations of proportional–integral–derivative type fuzzy controllers with parameter adaptive methods for an active magnetic bearing system

Abstract: This paper deals with the experimental control of a rotating active magnetic bearing (AMB) system using proportional–integral–derivative type fuzzy controllers (PIDFCs) with parameter adaptive methods. Three kinds of parameter adaptive method, including fuzzy tuner, function tuner and relative rate observer, have been proposed in the literature for tuning the coefficients of PIDFCs. However, only a simulation comparison between these methods for control of a second‐order linear system with varying parameters and time delay has been done. In general, theoretical models need to be confirmed and modified through experimental results. This paper provides experimental verification by applying PIDFCs with self‐tuning algorithms for control of a highly nonlinear AMB system. It is shown that the steady‐state error of the AMB system using the function tuner method is lower and the first resonant frequency of the AMB system using the relative rate observer method is higher than the other two methods, and the proportional–integral–derivative controller is quite unstable. The experimental results also show that all of the tuning methods can support a high rotation frequency of the AMB system. In practice, there are only a few differences between the three kinds of parameter adaptive methods.     

Generating content and display of library catalogue cards using XML technology

This paper presents the use of XML technology in modelling library documents, i.e. catalogue cards (and the type of reports) found in a library information system. The method of schema formation for content of various types of library catalogue cards is also described. The display of catalogue cards has been done based on described schemas. The display process has been performed in two steps. The first one extracts the content from a bibliographical record based on the schema describing catalogue card concepts. The result is an XML document containing all catalogue card concepts filled in with the corresponding content from the bibliographical record. Its display is being performed in the second step, resulting in an HTML document. As well as adequate representation of data obtained by searching bibliographical material databases, reporting is of prime importance in a library information system. Copyright © 2006 John Wiley & Sons, Ltd.     

Analogy-Based Practical Classification Rules for Software Quality Estimation

Software metrics-based quality estimation models can be effective tools for identifying which modules are likely to be fault-prone or not fault-prone. The use of such models prior to system deployment can considerably reduce the likelihood of faults discovered during operations, hence improving system reliability. A software quality classification model is calibrated using metrics from a past release or similar project, and is then applied to modules currently under development. Subsequently, a timely prediction of which modules are likely to have faults can be obtained. However, software quality classification models used in practice may not provide a useful balance between the two misclassification rates, especially when there are very few faulty modules in the system being modeled.This paper presents, in the context of case-based reasoning, two practical classification rules that allow appropriate emphasis on each type of misclassification as per the project requirements. The suggested techniques are especially useful for high-assurance systems where faulty modules are rare. The proposed generalized classification methods emphasize on the costs of misclassifications, and the unbalanced distribution of the faulty program modules. We illustrate the proposed techniques with a case study that consists of software measurements and fault data collected over multiple releases of a large-scale legacy telecommunication system. In addition to investigating the two classification methods, a brief relative comparison of the techniques is also presented. It is indicated that the level of classification accuracy and model-robustness observed for the case study would be beneficial in achieving high software reliability of its subsequent system releases. Similar observations are made from our empirical studies with other case studies.     

Java中基于Web组件的树型目录的设计及实现

在信息管理系统中,经常会遇到信息的维护操作,树型目录以它直观性的特点在信息维护中起到重要的作用。为了在信息管理系统中提供一种方便的树型目录维护,介绍了树型目录在Web信息展示中的使用,分析了树型目录的特点,提出并实现了基于Web组件的树型目录。在具体实现过程中,使用了Java小应用程序,以达到树型目录内容的灵活定制和使用的方便性。通过在实际项目中的使用,检验并到达了树型目录设计的目的。只要修改相应的配置文件,即可达到修改目录内容的目的。     

分布共享存贮器型MPP系统原理和实现方法

在两类并行计算机系统中,分布式存贮器(DM)型比共享存贮器(SM)型性能优越,但用户开发软件难度特别大。本文详细地介绍了用软件的方法将一个物理上的DM系统构成一个逻辑上的SM系统,即分布共享存贮器(DSM)系统的原理和实现方法。     

一种动态存储管理机制

动态存储管理是计算机必不可少的资源管理手段之一。现有的动态存储分配算法存在着效率不高、空间和时间开销较高等缺点。文中提出了一个用多级位示图目录来实现存储资源动态分配的算法，给出了多级位示图目录的结构和相应的算法，并分析了算法的效率，多级位示图目录算法具有结构简单，空间和时间开销小等优点。     

矿井提升机制动系统的PC控制算法与实现

结合矿井提升机制动系统的结构、任务特点及PC机发展的现状 ,提出了矿井提升机制动系统采用PC控制的两种实现方法 :软件方法和硬件方法。采用软件实现方法的主要技术关键是确定PC控制算法。文章对矿井提升机制动系统的PC控制算法进行了较为详细的分析计算 ,给出了制动系统的PC控制算法及其实现方法。     

工作站各类软件的备份与恢复方法综述

凡是由软件支持的硬件所面临的共同问题是对软件的维护,特别是开机时间长,利用率高,在微机控制下的各类仪器设备,更是如此。本文简要介绍几种快速、轻松备份、恢复文件系统的方法,来保障仪器设备的正常运转。这些方法不仅可用于微机自身操作系统的恢复,同样适用于应用软件的恢复、或是连同操作系统及应用软件一同恢复。