工程数据库管理系统设计、实现的几个关键问题

本文针对工程领域的特点，提出基于关系／网状的语义超图模型描述，以表达工程中不同语义类的多对多复杂对象关系；将该模型描述和表达的管理机制和基本数据在内存中统一管理和运行，使工程数据的存取效率大为提高；增加了大量通用和特殊功能，形成了功能更强、使用方便的Ｃ语言界面．在上述基础上自行研制并有自主版权的工程数据库管理系统ＥＤＢＭＳ（ｅｎｇｉｎｅｅｒｉｎｇｄａｔａｂａｓｅｍａｎａｇｅｍｅｎｔｓｙｓｔｅｍ）已在建筑ＣＡＤ领域中得到实际应用.     

数值模拟网格数据模型设计与实现

在等离子体动力学、电磁学理论等物理问题的数值模拟中,各类数值模拟程序产生了大量复杂结构的科学数据.一方面,计算程序需要以高效率的I/O方式存储数据,另一方面,数据需要在各类程序间很容易地交换与共享.随着数据的规模与复杂度不断增加,传统数据管理方式的局限性日益突出.为此,设计了面向计算物理领域的数据存储模型--数值模拟网格数据模型(JAD),引入元数据管理机制,对数值模拟程序数据对象进行抽象与封装,在HDF5软件库基础上实现了高层I/O函数库(JADLib),集成先进的数据存储技术,提供直观、易用的应用程序编程接口(API),使得数值模拟数据以统一格式高效率地存储.目前,JADLib已推广应用于高功率微波、惯性约束聚变等领域多个数值模拟程序中,与元数据管理系统(JADIS)、并行可视化系统(JaVis)建立了耦合,使得用户可以直接利用这些系统进行数据的浏览、分析及可视化,促进了应用程序间的数据共享.     

基于OWL的软件工程数据建模

网络本体语言(Web ontology language,OWL)是语义网技术的一个重要组成部分,适合于对复杂的数据进行语义描述和建模.在软件系统的开发过程中通常会产生大量结构复杂、语义丰富的数据,而建立一个灵活的语义模型是对各类软件工程数据进行统一管理的基础.从设计和实现海量软件工程数据管理平台的需求出发,提出了一种基于OWL的软件工程数据描述模型.该模型不仅能够对源代码、需求、测试、版本和缺陷数据进行描述,同时还能对这些数据之问的语义关联进行描述.通过案例分析对模型的有效性进行了讨论.     

An object-oriented database system Jasmine: implementation,application, and extension

We have devised an object oriented DBMS called Jasmine for advanced applications. The paper describes the implementation, application and extension of Jasmine in detail. We focus on the impact of the design of its object oriented model and language on database implementation technology. We describe what part of traditional relational database technology we extend to handle object oriented features such as object identifiers, complex objects, class hierarchies, and methods. We introduce nested relations to efficiently store and access clustered complex objects. We use hash based methods to efficiently access nonclustered complex objects. We provide user defined functions directly evaluated on page buffers to efficiently process method invocation. We devise object oriented optimization of queries including class hierarchies, complex objects, and method invocation. We incorporate dedicated object buffering to allow efficient access to objects through object identifiers. We also describe nontrivial applications of Jasmine and discuss the validity of object oriented databases. We focus on a constraint management facility, which can be implemented by taking advantage of the extensibility of Jasmine. The facility includes constraint rules, called design goals, for automatic database population required by engineering applications. Finally, we describe a view facility for schema integration also needed by engineering applications in distributed environments. We focus on how we extend Jasmine to implement the facility     

面向多数据源信息服务平台的访问控制模型

由于多数据源信息服务平台结构的耦合性和用户对不同数据对象安全访问的需求差异,从而增加了其访问管理的复杂性。提出了一种访问控制的层次模型,通过层级间的安全策略继承、重定义以及时态约束来满足应用对不同数据资源的安全操作需求,降低了访问控制的复杂性,并使得层次结构独立、灵活、易于扩展。     

Towards an optimum language data model

Maximizing the satisfaction of a value in an engineering design is usually limited by tradeoffs in which other values become unacceptably sacrificed. In a few cases, however, the maximization is limited by a boundary between what is mathematically possible and what is not. Round wheels, vertical pillars, and binary memory elements are examples of optimum engineering structures which result from such mathematical limits. It is proposed that optimum characteristics of a language data model result similarly by minimizing the variety of primitive data objects, the complexity of those objects, and the number of objects needed to represent data states. Reducing these measures is needed to combine both rich data structure and powerful operations in one language. The minimizations lead to a narrow range of designs for language semantics in which the potential advantages of specialization is small compared with the advantages of commonality. Universal language for support of technical literacy appears to be an appropriate scope of generality in language design.     

基于查询语言转换的多源数据统一访问框架

大数据时代,需要集成多样化数据管理分析工具完成业务需求,然而不同工具的数据访问接口标准不一,需要借助适配器进行接口转换以实现数据管理分析工具协作.因此,如何快速集成不同工具成为学术界与工业界亟待解决的问题.本文提出了一种基于查询语言转换的多源数据统一访问框架BAF4DUA(Bi-Adapter Framework for Data Unified Access),该框架采用双端接口适配方式,在数据提供者工具端和数据消费者工具端分别引入适配器对系统数据与查询语义进行适配,将查询语言与数据存储模型相分离,从而实现了数据提供者与数据消费者之间多对多、即插即用的数据访问,提高了应用的灵活性与扩展性.     

A Relational Representation of an Abstract Type System

Programming languages have traditionally had more data types than database systems. The flexibility of abstract types could make a database system more useful in supporting application development. Abstract types allow users to think about and manipulate data in terms and structures that they are familiar with. This paper proposes that databases have a type system interface and describes a representation of a type system in terms of relations. The type system model supports a variety of programming language constructs, such as user-defined parameterized data types and user-defined generic operations. The efficiency of the type system is compared to the access time of the database system.     

The living in a lattice rule language

This paper presents a rule-based query language for an object-oriented database model. The database model supports complex objects, object identity, classes and types, and a class/type hierarchy. The instances are described by ‘object relations’ which are functions from a set of objects to value sets and other object sets. The rule language is based on object-terms which provide access to objects via the class hierarchy. Rules are divided into two classes: object-preserving rules manipulating existing objects (yielding a new ‘view’ on objects available in the object base) and object-generating rules creating new objects with properties derived from existing objects. The derived object sets are included in a class lattice. We give conditions for whether the instances of the ‘rules’ heads are ‘consistent’, i.e. represent object relations where the properties of the derived objects are functionally determined by the objects.     

异构数据转换关键技术的实现

针对不同信息系统之间的异构数据共享使用问题,结合Object Pascal语言在功能及逻辑性方面的优势,设计异构数据转换流程和步骤,分析异构数据转换的关键技术,提出数据转换规则动态定义、动态校验编译及调用执行方法,描述基于该方法的异构数据转换实现过程。实践结果证明,基于该方法的异构数据转换技术具有可行性且转换效率高。     

User interfaces for structural engineering relational data base

The needs of engineers in their interaction with engineering data bases are very different from those of their counter-parts in the business world. Business data base management system interfaces typically provide only a single mode of textual communication, usually a structured query language. However, in an idealengineering data base interface, an engineer would be able to define constraints, give examples, point at parts of pictures, and (sometimes) use several modes of communication simultaneously. The paper presents an example from an engineering design application to show how a traditional query language can be enhanced to accommodate the engineering needs. The paper further describes a conceptual approach for multimodal engineering data base interface combining multipurpose graphics, an engineering query language, and other interface methodologies in an engineering workstation environment.     

A service acquisition mechanism for server-based heterogeneousdistributed systems

This paper presents a mechanism that facilitates and enhances the use of independently administered remote network servers in the presence of server interface heterogeneity. The mechanism is designed under the client-service model, which extends the client-server model with an abstraction of service to decouple abstract server capabilities from concrete server interface specifics such as server interface binding protocols and the interface operation invocation protocols. The mechanism selects servers, accommodates server interface heterogeneity, and handles server access failures as per the abstract server capabilities desired by the client. It could return the identity of the server used for each service access invocation to facilitate billing, refining service specifications, and reporting server-specific errors. This paper also illustrates a C library interface to this mechanism, and describes a language veneer over the C programming language demonstrating how a typed procedural language could be extended by a few language constructs to support the mechanism under the client-service model. In this language, server capabilities are referenced by abstract data type (ADT) objects, and are accessed by invoking the objects' interface operations using a call-by-value-result paradigm     

通用试飞数据处理查询语言FTSQL

给出了一种通用数据处理用工程数据库查询语言FTSQL。该语言可入高级程序设计语言,提供了工程数据的标准访问接口,采用该语言可使数据处理部件化,支持数据处理软件系统的集成化、规范化以及系统的可重要性要求。     

高速网络的自相似业务模型及其性能评价

文中介绍了９０年代高速网络性能评价领域中一个重大发现，即真实的网络业务具有自相似性。传统的基于Ｍａｒｋｏｖ模型的性能评价结果对自相似业务已不再适用，需要研制新的模型与工具。文中介绍了自相似过程的数学定义及其性质，讨论了重尾分布和诺亚效应及它们与自相似过程的关系，还介绍了几种生成自相似业务的方法和自相似业务模型下队列系统性能评价方面的研究成果。     

Object Identity in Database Systems

The concept of object identity and implementation of object identity in some systems have been explained in literature.Based on an analysis on the idea of data scheme in ANSI/X3/SPARC,this paper presents the concept of full-identity,which includes entity identity,conceptual object identity,and internal object identity,In addition,the equality of objects,which is richer and more practical,is discussed based on the full identity of objects.Therefore,the semantics and constructions of the identity for the complex objects are fully observed,and some appliactions in object management,version management,and user interface are found.Also,it could support the combination of O-O model with V-O model.     

Management of complex structural engineering objects in a relational framework

To structure the development of an integrated building design environment, the global representation of the design data may best be organized in terms of hierarchies of objects. In structural engineering design we deal with large sets of independent but interrelated objects. These objects are specified by data. For an engineering design data base the system must be able to model the objects composing the design as well as to manage effectively the design data. The data base management system therefore needs to have some knowledge of the intended use of the data, and must provide an abstraction mechanism to represent and manipulate objects. Much recent research in engineering data bases focuses on object management for specific tasks but gives little attention to the shareability of the underlying information. This paper describes an architecture for the management of complex engineering objects in a sharable, relational framework. Potential application of this approach to object management for structural engineering analysis and design is discussed.     

基于区块链的水利数据共享平台开发与应用研究

针对水利政务各部门存在业务纵向独立,跨部门数据共享与业务协同困难等问题,为提升水利政务办事效率与群众满意度,研究并实现一种基于区块链技术的水利数据共享平台。利用区块链分布式共享、不可篡改等特性,将水利数据去中心化存储;采用应用服务与数据管理分离的架构模型与一致性访问接口,解决各水利应用间的数据共享问题;结合智能合约与数字签名技术,实现数据访问与共享的去信任化和智能化。该研究已应用于围绕电子采砂证照的水利数据共享场景中,应用分析表明：平台可实现水利数据去中心化存储与访问,实现水利数据的跨部门安全可信共享,提高水利政务协同工作效率,研究成果可为各地方、 部门和层级间政务数据的安全互通起示范作用。     

一种逻辑层次连接的工程数据库设计库方法及应用

以自行研制的工程数据库管理系统ＥＤＢＭＳ为背景,讨论了工程数据库设计中的一些问题,并结合工程应用,提出了一种以逻辑分层为基础,结合对象间连接关系来进行逻辑层次连接的工程数据库设计方法,它在数据检索应用中能显著地提高使用效率。