HLB型悬臂液下泵在锌电解工序中的应用与改进

文章从结构、材质方面分析了HLB型悬臂液下泵的可靠性及安全性，提出了对泵操作维护的具体要求，对该泵的改进展开了有益的探讨，并成功应用于生产实践。     

Preventive maintenance models with random maintenance quality

In real-world environments it is usually difficult to specify the quality of a preventive maintenance (PM) action precisely. This uncertainty makes it problematic to optimise maintenance policy. This problem is tackled in this paper by assuming that the quality of a PM action is a random variable following a probability distribution. Two frequently studied PM models, a failure rate PM model and an age reduction PM model, are investigated. The optimal PM policies are presented and optimised. Numerical examples are also given.     

大中型医院网络故障的快速维护和管理

随着医院信息化的普及与提高，对网络快速维护和管理提出了更高的要求，一旦网络系统发生故障就必须迅速找出原因及时排除故障。要想作出快速响应，就必须对网络原理、本单位网络拓朴结构有所认识，并且对网络系统文档做好日常的管理工作。     

协同办公平台项目实施的解决方案

软件实施活动的目的是生产可执行的软件单，该文将软件工程的相关知识应用到项目实施中，提出了一套标准化的软件项目实施过程，实践性较强。     

机械的可靠度分析

通过对机械失效的分析，讨论了机械失效对可靠度的影响，提出了机械工作可靠度在设计时的计算方法和在设计时应采取的措施。     

浅谈医疗仪器维修

本介绍了医疗仪器维修方法，谈了一些常见医疗仪器故障的维修技巧，并讲述了在维修医疗仪器时遇到间歇性故障和噪音干扰时的对策。     

用有限自动机和拓扑排序理论提高MIS开发效率

利用有限自动机和拓扑排序理论编写的一个工具软件．能直接处理数据库分析人员利用CASE工具产生的带中文注释的表定义DDL脚本文件．并可按引用完整性的要求。对各条DDL语句自动排序后．直接在RDBMS中创建用DDL语句定义的各表。使数据库分析段和程序设计阶段有机结合起来，提高了工作效率；同时，由于脚本文件已含有表名、字段名的详细注释，可省去相应的中文数据字典，也减少了文档维护的工作量。     

网络软件自动升级技术剖析

文中剖析了采用Internet自动下载最新版本的软件升级编程机制，使软件的升级维护在客户端自动下载完成，非常方便快捷。     

一种高效的视图维护算法

通过选择性算法将增量式视图维护和视图自维护有效地融合在一起．同时它还利用相关性算法对不相关更新进行过滤，可以有效地降低消息总数和数据的通信量，从而大大提高视图维护的效率，具有现实的应用意义．     

Maintaining Views in Object-Relational Databases

View materialization is an important way of improving the performance of query processing. When an update occurs to the source data from which a materialized view is derived, the materialized view has to be updated so that it is consistent with the source data. This update process is called view maintenance. The incremental method of view maintenance, which computes the new view using the old view and the update to the source data, is widely preferred to full view recomputation when the update is small in size. In this paper we investigate how to incrementally maintain views in object-relational (OR) databases. The investigation focuses on maintaining views defined in OR-SQL, a language containing the features of object referencing, inheritance, collection, and aggregate functions including user-defined set aggregate functions. We propose an architecture and algorithms for incremental OR viewmaintenance. We implement all algorithms and analyze the performance of them in comparison with full view recomputation. The analysis shows that the algorithms significantly reduce the cost of updating a vieww hen the size of an update to the source data is relatively small. Received 23 May 2000 / Revised 27 March 2001 / Accepted in revised form 30 April 2001 Correspondence and offprint requests to: Jixue Liu, School of Computer and Information Science, University of South Australia, Mawson Lakes, Adelaide SA5084, Australia. Email: jixue.liu@unisa.edu.auau