A frame-based model for large manufacturing databases

A major requirement of database systems in engineering design and manufacturing applications is support for storage and maintenance of complex objects. Frame based systems are capable of modeling complex objects. However, many of these systems are implemented in main memory. As the number of objects to be stored far exceeds the capacity of the main memory of a computer, such an implementation is often unusable. Therefore, new ways to model and manipulate large manufacturing databases are needed. In this paper we present an implementation of a frame based system on top of the POSTGRES extensible database system. Such an implementation combines the advantages of database management and frame based systems and allows for the development of large manufacturing database applications with minimal effort.     

Integrating relational and object-oriented database systems using a metaclass concept

This paper presents a specific approach of integrating a relational database system into a federated database system. The underlying database integration process consist of three steps: first, the external database systems have to be connected to the integrated database system environment and the external data models have to be mapped into a canonical data model. This step is often called syntactic transformation including structural enrichment and leads to component schemas for each external DBMS. Second, the resulting schemas from the first step are used to construct export schemas which are then integrated into global, individual schemas or views in the third step. In this paper we focus on the first step for relational databases, i.e., the connection of a relational database system and the mapping of the relational model into a canonical data model. We take POSTGRES as the relational database system and the object-oriented federated database system VODAK as the integration platform which provides the open, object-oriented data model as the canonical data model for the integration. We show different variations of mapping the relational model. By exploiting the metaclass concept provided by VML, the modelling language of VODAK, we show how to tailor VML such that the canonical data model meets the requirements of integrating POSTGRES into the global database system VODAK in an efficient way.     

The POSTGRES rule manager

The rule subsystem that is being implemented in the POSTGRES DBMS is explained. It is novel in several ways. First, it gives users the capability of defining rules as well as data. Moreover, depending on the scope of each rule defined, optimization is handled differently. This leads to good performance both when there are many rules each of small scope and when there are a few rules each of large scope. In addition, rules provide either a forward-chaining or a backward-chaining control flow, and the system chooses the control mechanism that optimizes performance whenever possible. Priority rules can be defined, allowing a user to specify rule systems that have conflicts. This use of exceptions seems necessary in many applications. Database services such as views, protection, integrity constraints, and referential integrity can be obtained simply by applying the rules system in the appropriate way. Consequently, no special-purpose code need be included in POSTGRES to handle these tasks     

The design and implementation of the Ariel active database rulesystem

Describes the design and implementation of the Ariel DBMS and its tightly-coupled forward-chaining rule system. The query language of Ariel is a subset of POSTQUEL (the POSTGRES QUEry Language), extended with a new production-rule sublanguage. Ariel supports traditional relational database query and update operations efficiently, using a System R-like query processing strategy. In addition, the Ariel rule system is tightly coupled with query and update processing. Ariel rules can have conditions based on a mix of selections, joins, events and transitions. For testing rule conditions, Ariel makes use of a discrimination network composed of a special data structure for testing single-relation selection conditions efficiently, and a modified version of the TREAT algorithm, called A-TREAT, for testing join conditions. The key modification to TREAT (which could also be used in the Rete algorithm) is the use of virtual α-memory nodes which save storage since they contain only the predicate associated with the memory node instead of copies of data matching the predicate. In addition, the notions of tokens and α-memory nodes are generalized to support event and transition conditions. The rule-action executor in Ariel binds the data matching a rule's condition to the action of the rule at rule fire time, and executes the rule action using the query processor     

基于Cö S环境的商业决策支持系统研究与设计

介绍基于Ｃ／Ｓ环境的商业决策支持系统的设计方法与实现技术,着重讨论商业决策支持系统的主要结构,模型和知识的表示与实现技术,处理机的功能,数据抽取技术等问题。     

面向中小型燃气具行业产品数据管理系统的研究与实现

分析了中小型燃气具企业特点,结合广东某燃气具公司存在的实际问题,探讨了在中小型燃气具企业建设和实施产品数据管理系统的方法;论文利用ASP.NET技术和SQL技术开发了基于Web的产品数据管理系统,给出了系统的结构设计方案、采用的关键技术和主要功能实现。系统实施后,规范了其物料流程,实现了基于网络的产品数据管理。系统具有适度柔性,易于推广。     

导引头电子舱数据采集系统的设计与实现

为了在实际应用中完成导引头电子舱的数据采集任务,通过对数据采集的相关内容介绍和PCI总线规范实现机制的仔细研究和详细分析,给出了数据采集系统的结构框图和工作原理以及其硬件电路的具体实现,此外,还提出了PCI设备驱动程序的几种常用开发方法;该系统能够实现对实验数据的正确采集和有效处理,其性能和指标均能够满足某型号导引头电子舱数据采集系统的要求,在工程应用中证明是可行的,而且具有较强的通用性和灵活性.     

纹织CAD电子白板系统的设计与实现

本文描述可以实现协同操作的纹织CAD电子白板系统的设计与实现。讨论端点间结构、客户端／服务器结构和通信数据结构的设计，详细说明服务器和客户端软件的程序流程、双方的时序、系统消息及其加密解密算法的具体实现。     

内联网数据仓库技术及应用

本文讨论了内联网数据仓库技术的需求和实现,提出了由操作数据层、数据提取层、数据仓库层、分析处理层和用户层构成的五层结构的企业内联网数据仓库系统,并详细探 讨了建立实用内联网数据仓库系统的关键技术     

基于网络的数据存取安全性探讨

1 引言计算机网络以及Internet、Intranet的出现与发展引发了计算机领域新的应用高潮,诸如电子商务、远程教育、远程医疗、数字图书馆。网络计算以及层出不穷的网络服务和网站使得计算机网络由少数专门人员使用成为成千上万广大用户工作与生活不可缺少的助手。但是随之而来的网络黑客、病毒以及网上的恶意攻     

干部选拔决策支持系统中数据仓库的设计

基于数据仓库的决策支持系统是现今决策支持技术应用的主流。本文结合数据仓库、联机分析处理、数据挖掘、模型库系统、知识库系统等技术提出了一个干部选拔决策支持系统的解决方案，并就干部选拔数据仓库的设计和实现进行了分析和探讨。     

The computational completeness of extended database query languages

The computational completeness is demonstrated of certain extended database query languages, namely, POSTGRES and GENESIS, and a language defined by A. Aho and J. Ullman (1979). The method used is to implement a Turing machine interpreter in each of the languages. These query languages were defined as extensions to traditional database languages in order to encompass certain specific new applications. Results show that these extensions have already encompassed all the computational power of any programming language     

WEB数据获取系统的设计与实现

WEB上存在着大量数据,为了有效地利用这些数据,必须把它们从WEB页面中获取出来存放到数据库中.本文首先介绍了WEB环境下数据获取的相关概念与技术,基于此,提出了一种基于XML的WEB数据获取系统结构,讨论了它的主要组成.最后,给出了系统的实现方法.     

基于内容管理的烟草企业信息仓库系统

在企业生产运作过程中会产生结构化数据和非结构化信息,针对非结构化信息的内容管理理论进行讨论,分析烟草企业在内容管理上的需求。根据烟草企业的特征,将信息流程设计为常规信息处理和信息预警流程。讨论系统框架,分为用户端层、中间应用层及数据存储层。对系统实现中采用的关键技术进行介绍。     

一个基于Java的可视化挖掘工具的设计和实现

介绍了一个可视化挖掘工具,给出了其框架体系结构,并主要从数据挖掘技术、数据视图及其操纵界面技术、系统安全性三个方面作了介绍。     

基于FPGA的高速采样系统实现

介绍一种应用于激光回波数据采集的两路双通道250MHz高速采样电路设计及基于FPGA的控制与数据处理的实现方法。阐述了采样系统的设计实现、硬件布局布线,并提出对IDDR加物理与时序约束条件和利用异步复位来同步采样数据接收使能信号的方法,从硬件和软件两方面保证采样数据的同步传输。仿真和实验结果表明,该高速采样系统的设计性能稳定,数据传输的同步性理想,设计达到了预期的效果。     

PDM系统中CAE数据管理的关键技术研究与实现

PDM系统中CAE的数据管理是影响企业应用集成性能的关键因素之一。对PDM中CAE数据的集成方式进行了探讨,根据CAE数据特点结合PDM系统提出了层次化管理技术、基于类型的数据组织技术和数据发放流程技术。在结合实际的基础上,详细介绍了其实现技术及特点,最后展望了在企业应用系统集成中的前景。     

燃气能源测试系统研究

介绍了一种能够采集、存储、读取以及实时监测的燃气能源测试系统研究，讨论了各功能模块的应用以及它们之间的传输方式并给出该系统的硬件实现方案。通过用VB实现的软件界面进行控制硬件实现功能，最后在上位机上读取采集的数据和实时标定波形显示。     

基于ActiveX的AutoCAD考试自动评卷系统的设计

介绍了AutoCAD考试系统设计的关键技术,着重分析了提取AutoCAD图形对象数据信息的方法和自动评卷功能的实现.     

Development and Structure of an X.25 Implementation

This paper describes experience with an implementation of the X25 communication protocols for accessing public data networks. Ihe implementation effort is characterized by: 1) the development of a formalized protocol specification on which all further implementation work is based, and 2) the use of Concurrent Pascal as the implementation language. The main features of the formalized protocol specification are given, and a method for deriving a protocol implementation based on parallel processes, monitors, and classes is explained. The overall structure of the system and the step-wise refinements leading to the complete implementation are discussed. Some comments on the possible implementation on multiple microprocessors are also given.