Empirical Data Reference Behavior in Data Base Systems

During the past several years a considerable amount of effort has gone into the measurement, analysis, and modeling of program behavior. Most of the work either assumes the existence of a reference string, which is then used in various ways, or attempts to produce a model for the process by which such reference strings are generated. With very few exceptions the reference strings that have been measured characterize virtual memory utilization, reflecting the fact that the motivating force behind these research activities is the desire to understand the behavior of virtual memory paging systems.     

数据库安全与安全数据库管理系统设计

过去的十几年中,许多专家学者在数据库安全领域作了大量的研究工作,取得了不少研究成果,其中有些成果已经运用到商品化的安全数据库产品中.本文首先介绍了数据库安全的重要意义和评估安全数据库的相关标准,讨论了保证数据库安全的机制,并进一步研究了实现安全数据库所应考虑的各方面问题,包括建立数据库安全模型、实施存取控制策略、数据加密、审计与攻击检测等.最后给出了几个安全数据库研究原型和产品.     

基于对象的关系数据库管理系统的设计与实现

对象关系数据库技术是在继承关系数据库技术的基础上,增加面向对象特性,可满足GIS等应用领域的需求而发展起来的一种新型数据库技术,它既具有管理复杂数据的能力,又能提供强有力的查询功能。本文基于面向对象的关系数据库管理系统,提出直接在对象关系数据库中存储矢量地理时空数据的方法,实现了空间数据、时间数据和属性数据的一体化管理。     

基于对象的关系数据库管理系统的设计与实现

对象关系数据库技术是在继承关系数据库技术的基础上,增加面向对象特性,可满足GIS等应用领域的需求而发展起来的一种新型数据库技术,它既具有管理复杂数据的能力,又能提供强有力的查询功能。本文基于面向对象的关系数据库管理系统．提出直接在对象关系数据库中存储矢量地理时空数据的方法,实现了空间数据、时间数据和属性数据的一体化管理．     

Reorganizing the files in Data Base Management Systems

A model of Data Base Management System (DBMS) including features of dynamic reorganization of files is presented. A controlled Markov chain is assumed to describe environment changes of the DBMS. The problem of optimal reorganization of the files is presented in terms of dynamic programming.     

影响分布式数据库系统数据存取效率的因素

论述了分布式数据库环境对数据通信的要求 ;对影响分布式数据库系统数据存取效率的因素进行了探讨。     

A Survey of Developments in Distributed Data Base Management Systems

Distributed data base management systems extend the capacities of computing systems to give many people access to a wide range of information. These systems, which arise from the combination of recent important advances in computer networks with general-purpose data base management systems, should shortly represent another significant step in commercial system development. So it is not surprising that they have been the focus of much research and development activity in both the academic and industrial environments.     

The Information Systems Plan and the Data Base Plan

The data base management system (DBMS) is becoming the heart of modern information system architectures. To take full advantage of a DBMS's data sharing potential, the MIS manager must carefully analyze systems implementation priorities. An information systems plan (ISP) provides the data administration staff with valuable input that aids in determining the appropriateness of applications for the DBMS and in establishing a logical, phased implementation schedule. An ISP can also prove valuable to data administration in preparing and executing a data base plan.     

Data Base Interfaces

We often read about the need for better data base interfaces. But what precisely is meant by data base interfaces, and what constitutes better? This lack of precision can result in wrong solutions being promoted for real problems —or good solutions that may only solve part of the problem. The development of a better interface demands that data base designers and imple-mentors understand the varied nature of data base interfaces and match improvement goals to these interfaces in meaningful and practical ways.     

Relational Data Base Machines

Relational data base machines using head-per-track disk technology or its electronic equivalent can move processing logic closer to the data, providing simplified storage organizations for large-scale applications.     

Data Base Machines are Coming, Data Base Machines are Coming!

New research efforts and recent advances in hardware technology may soon make the commercial data base machine a reality.     

多机器人系统的研究现状

介绍了多机器人系统的研究进展及现状,对该领域内的主要内容(思想源泉、体系结构与控制、通信、学习、可重构机器人)的研究现状作了分析和介绍,还提出了一些未来值得研究的议题。     

Trends in Data Organization and Access Methods

There has been a trend in applications programming over the past fifteen years from highly structured programs and loosely structured data toward loosely structured programs and highly structured data. Transaction oriented systems and other data directed programs make greater demands on the memory hierarchy of a computer system and have given rise to the need for storage media which are to some degree structurable under program control. Overhead in operating systems and large on-line application programs is described as a symptom of "static" and "dynamic" mismatch problems in the storage hierarchy. Some new memory organization techniques beginning to appear on computers may allow greater efficiency in data directed systems since they allow the programmer to store the structure and the content of his data separately.     

多单片机系统中的数据交换

在日新月异的数字世界里,各种单片机、DSP等微处理器已被用于各个领域。由于系统的庞大或者是实时性要求,一个CPU在一些系统中已不能独立完成其特定的任务,必须借助多个CPU的配合使用才能完成。而各CPU之间往往又不是孤立的,是相互紧密联系的,所以多CPU相互之间的数据交换无疑成了我们经常面对的课题。单靠以往的几个I/O口的握手电平信号来交换数据已满足不了人们的要求,必须采用其它更科学和更可靠的方法进行大量数据的交换。本文列举出了多单片机系统中数据交换的几种可行方法,并提出其优缺点,希望能供广大电气工程师在设计此类课题时参考。     

2015年数据中心存储动态

快捷键院简洁性和可视化
　　2015年,数据复杂性失控,简洁性和可视化变得尤为重要。数据中心将由快捷键组成！数据复杂性这个问题不仅是由容量增长导致的。根据IDC报告,移动和传感器设备正在生成新的端点,到2020年将达到200亿台,数据就是在这些端点中创建的。这些数据将包含更多需要索引的对象,而每个对象由于需要收集更精细的数据而比以往更大。不断传输数据带来了新的、独一无二的性能和可用性问题。因为可能用来为未来分析创建上下文,所有数据都必须保留更长时间。然而,唯一没有增长的是管理预算。与此同时,千禧一代新劳动力是伴随着方便易用的 iPad 长大的,互联网不会容忍缺乏直观用户界面和报告的老旧样式的管理系统。存储厂商必须为存储和数据本身提供更多、更好的监控以及管理和报告工具,可视化将成为重中之重。