基于对象一关系一属性数据模型的空间半结构化数据存储管理研究

对象一关系一属性数据模型相对传统的结构化数据模型，用更丰富的数据语义区别了对象类属性和关系类型属性两个概念，使其适用于半结构化数据的存储与管理。从分析空间数据的半结构化特征入手，以空间教据的嵌套关系为管理对象，实现了在关系型数据库中对空间半结构化数据的存储与管理。     

对象-关系模型在空间数据管理中的应用

对象-关系模型已经成为解决增长型数据管理以及分析非传统数据库应用程序的新标准。本文介绍了在某实际应用系统中使用对象-关系模型存储和管理空间数据的方法，简化了应用程序的开发，提高了系统性能。     

基于元数据管理的半结构化数据安全转换方法

为了提升半结构化数据的安全转换能力、降低数据转换输出误码率(BER),提出基于元数据管理的半结构化数据安全转换方法。构建云存储动态半结构化数据的Hash编码模型,采用动态随机码元调制方法,分析云存储动态半结构化数据的参数统计特征量。采用模糊自相关融合调度方法,构建云存储动态半结构化数据的直觉模糊度对偶集。采用统计分析和概率密度特征采样的方法,构建云存储动态半结构化数据分簇聚类融合模型。采用元数据管理和参数模糊度辨识,实现半结构化数据安全转换和多属性群决策。根据分组交换的方法,实现云存储动态半结构化数据动态分析和聚类。结合信息聚类和自适应学习方法,实现半结构化数据安全转换和编码控制。仿真结果表明,采用该方法进行半结构化数据安全转换的准确性较高、数据输出误码率较低、融合性较好,提高了半结构化数据的安全传输能力。     

一种用于存储与查询半结构化数据的新方法

由于半结构化数据缺乏模式信息,因而半结构化数据的存储与查询将是一个十分重要且具有挑战性的研究课题。利用关系数据库存储半结构化数据可以重用数据库的查询优化器和事务处理机制,能够保证半结构化数据的一致性和完整性。该文提出一种实现半结构化数据存储与查询的新方法,该方法使用关系数据库系统来实现半结构化数据的存储与查询。给出了把基于半结构化数据的查询重写为基于关系的查询的算法,同时介绍一个可视化查询程序。     

XML数据流中祖先-后裔关系匹配算法

在祖先-后裔关系匹配算法中,多数都是首先利用XML解析器将XML文档解析分裂为元素(或属性) 列表进行存储,然后在这些分裂得到的元素(或属性) 列表之间进行祖先-后裔关系的结构连接.该文的算法SSD不需要事先将源XML文档分裂为元素(或属性) 列表进行存储,而是直接将源XML文档作为输入,采用SAX来产生XML数据流,然后基于XML数据流实现祖先-后裔关系匹配.通过分析可知,该算法适用面广,仅需要对源XML文档进行一次扫描,占用系统资源少,且具有很高的匹配效率.     

XML与非结构化数据管理

该文从数据的存储方式入手,列出了目前业界对非结构化数据的几种管理方式和方法,并提出了通过XML,采用"非结构化数据-半结构化数据-结构化数据"的逐步转换方式,将目前难以管理的非结构化数据转到容易管理的结构化数据的方法,达到了非结构化数据为我所用的目的。     

基于Oracle Spatial的GIS数据组织及查询

GIS的一个难点是实现空间数据和属性数据的一体化存储和管理,研究用Oracle Spatial技术来解决这个问题。在确定了采用对象一关系模型来存储GIS数据后,比较了空间数据的两种导入方式,在此基础上,选用EasyLoader工具将GIS数据导入到Oracle数据库中,再用四元树索引为其建立索引。最后,选择Java作为开发工具,采用JDBC方式与Oracle数据库相连并实现了对GIS数据的查询。     

一个基于模式的XML存储模型

XML基于半结构化数据模型,而半结构化数据很难统一存储和管理。文章提出了一个基于模式的XML存储模型SBSM,并定义了如何在该模型上进行相关的操作,该模型克服了对象-关系映射模型的局限性,并支持直接在模型上进行查询操作。     

半结构化数据到结构化数据的模式抽取

在分析现有的半结构化数据的存储方式及存在的问题基础上,引入了小集合属性、集合属性、聚类集合、模板集合、父属性序列等概念,借助映射表达语言STORED,提出了一种基于数据挖掘的半结构化数据到结构化数据的模式抽取的方法。     

基于数据注册中心和World Wind的空间数据存取

传统的集中式数据库、文件系统已经不能有效地处理海量增长数据的存取和管理,而需要采用分布式存储。同时,伴随着对空间信息研究的快速发展,地理信息系统应用逐步走入人们的生活。针对空间数据的存取问题,本文结合数据注册中心和World Wind Java,实现对空间数据进行存取。首先利用元数据与数据分离的分布式存储方式,以KML来统一组织和管理各种空间数据属性,实现对空间数据的存储,最后用World Wind Java实现对空间数据的读取和展示,以便对采集的空间数据进行有效的存取及为行业应用提供服务,以充分发挥数据的作用,大大减轻对空间数据存储的负担。     

Object modelling and formal specification during real-time system development

Object oriented techniques promote understanding of requirements leading to flexible and extendible designs. The use of formal specification techniques ensures a complete understanding of system requirements and provides sound foundations for subsequent testing and verification. This paper describes the use of the Z and Timed CSP formal specification techniques to support object modelling during real-time system development. Relationships between class attributes are specified within the corresponding Z schemas and inheritance relationships between classes are formally specified using the schema extension mechanism of Z. Z is used to specify the domain types of the attributes of classes identified during object oriented analysis and design. Z is also used to produce model based specifications of the methods within classes that are specified informally during functional analysis. Dynamic analysis identifies events, states and temporal relationships between events. Timed CSP is used to formally specify this information as well as timing information that is necessary during real-time system development.     

织女星网格元信息管理系统的设计与实现

网格中有关资源的信息是网格的元信息,有效地存储、管理这些元信息是网格首先要解决的问题.使用半结构化数据模型ORA-SS描述网格元信息可以表达资源信息间的多元关系,明确地区分资源的属性和资源之间关系的属性,克服LDAP只能表达简单的树形结构的缺点.提出了一种将ORA-SS模型应用到织女星网格元信息管理的方法,并给出了具体的设计和实现方案.     

CIM模型在关系数据库中存储方案的设计

CIM模型在关系数据库中存储方式的好坏,直接影响电力系统分析软件的运行效率。本文首先总结CIM模型的特点,指出对象模型向关系模型映射的必要性,然后提出类、对象、对象属性类型、对象属性以及类之间的关系向SQL Server 2005数据库映射的一般方法,最后以拓扑包主框图为例,用DDL语言实现框图中的基本关系。在电网分析平台中使用该方法来存储CIM对象,加快了平台的开发进度。     

A Formal Definition of the Chimera Object-Oriented Data Model

In this paper we formalize the object-oriented data model of the Chimera language. This language supports all the common features of object-oriented data models such as object identity, complex objects and user-defined operations, classes, inheritance. Constraints may be defined by means of deductive rules, used also to specify derived attributes. In addition, class attributes, operations, and constraints that collectively apply to classes are supported.The main contribution of our work is to define a complete formal model for an object-oriented data model, and to address on a formal basis several issues deriving from the introduction of rules into an object-oriented data model.     

An object deputy model for realization of flexible and powerful objectbases

In object-oriented databases, data and methods are combined by objects and their classes. Information redundancies are removed by the notions of class hierarchy and inheritance. This contributes the realization of high-performance systems. However, the flexibility of object structures still remains a problem due to its encapsulation feature. In this paper, we introduce an object deputy model which extends conventional object-oriented models with the concepts of deputy objects and deputy classes. A deputy object has its own identifier and may possess its own attributes and methods. It can also have attributes that are computed from values stored within its source object, and can be associated with methods generated from these of the source object. The inheritances are realized by switching operations, which make it possible to realize controllable, selective and dynamic inheritance structures. Schemata of deputy objects are defined by deputy classes which can be derived by an object deputy algebra. An object can have many deputy objects, and several objects can share a single deputy object. Thus, objects can be indirectly divided and combined through their deputy objects. We show that several difficult database problems, such as flexible views, objects with more than one role, object migration, and multiple inheritance become much easier in this model. The data-knowledge coordination model developed for the integration of distributed databases and knowledge-bases can also be realized easily by the object deputy model. Finally, we discuss several advanced database applications of this model, such as geographic databases, virtual office systems, and distant education systems.     

Extending the ODMG standard with views

Views are an important functionality provided by the relational database systems. However, commercial object-oriented database systems do not support a view mechanism because defining the semantics of views in the context of an object-oriented model is more difficult than in the relational model. Indeed, views are not included in the ODMG standard. In this paper, we present a proposal aimed at including views in the ODMG, by extending the object model and the object definition language (ODL). We consider object-oriented views as having the same functionality as relational views. Views are included in the object model in such a way that (i) views make a new kind of data type definition, just as are classes, interfaces and literals, (ii) an IS-VIEW relationship is introduced in order to specify the derivation of a view from its base class, and (iii) a view instance preserves the identity of its base instance. A view can import attributes, relationships and operations from its base class, and it can also add new operations, derived attributes and derived relationships. The extent of the view is defined by an object query language (OQL) predicate. We also describe a C++ binding showing the practicability of the proposed model.     

局部离群点挖掘算法研究

离群点可分为全局离群点和局部离群点.在很多情况下,局部离群点的挖掘比全局离群点的挖掘更有意义.现有的基于局部离群度的离群点挖掘算法存在检测精度依赖于用户给定的参数、计算复杂度高等局限.文中提出将对象属性分为固有属性和环境属性,用环境属性确定对象邻域、固有属性计算离群度的方法克服上述局限;并以空间数据为例,将空间属性与非空间属性分开,用空间属性确定空间邻域,用非空间属性计算空间离群度,设计了空间离群点挖掘算法.实验结果表明,所提算法具有对用户依赖性少、检测精度高、可伸缩性强和运算效率高的优点.     

卫星测控站监控系统软件结构的研究与实现

测控站监控系统由于系统规模小、设备复杂,缺少商业化控制软件的支持,因而建造成本高,周期长,缺少灵活性和扩展性,系统维护困难。不适应航天技术发展的需要。通过分析测控站监控与一般工业控制的差别,借鉴组态软件设计思想,设计面向对象的设备对象模型和显示模型,为设备对象定义设备参数、数据处理函数、通信接口参数等属性,为显示元素定义静态和动态的图形属性、显示方法以及与设备对象的关联。依据配置文件,在运行时,生成设备对象。完成设备数据的接收、处理和控制;每个显示配置文件形成一幅显示画面;显示元素通过关联的设备参数更新显示属性。这种方法为在特定领域内构建监控系统提供了经济实用的解决方案。     

基于几何元素的城市三维地理信息系统空间数据模型

空间数据模型是城市三维地理信息系统建立的核心问题。基于不同的城市空间对象划分方法,提出了城市三维地理信息系统的十八个空间数据模型:把空间现象抽象为六类对象:点对象、线对象、规则面对象、规则体对象、不规则对象和DTM,基于六种几何元素(点、直线段、多边形、函数构造面、TIN面片、规则体素)的不同组合,提出了城市三维地理信息系统的九个空间数据模型;把空间现象抽象为五类对象:0维空间对象(点对象)、一维空间对象(线对象)、二维空间对象(面对象)、三维空间对象(体对象)和DTM,基于六种几何元素的不同组合提出了八个空间数据模型;把空间现象抽象为0维对象(点对象)、一维对象(线对象)、二维对象(面对象)、三维对象(体对象)、DTM,基于点、直线段、TIN面片、多边形、规则面、不规则面六类几何元素提出了一个空间数据模型。通过对一个数据模型的实验验证和各模型的理论分析,表明了模型的特点及可行性。     

Index configuration in object-oriented databases

In relational databases, an attribute of a relation can have only a single primitive value, making it cumbersome to model complex objects. The objectoriented paradigm removes this difficulty by introducing the notion of nested objects, which allows the value of an object atribute to be another object or a set of other objects. This means that a class consists of a set of attributes, and the values of the attributes are objects that belong to other classes; that is, the definition of a class forms a hierarchy of classes. All attributes of the nested classes are nested attributes of the root of the hierarchy. A branch of such hierarchy is called apath. In this article, we address the problem of index configuration for a given path. We first summarize some basic concepts, and introduce the concept of index configuration for a path. Then we present cost formulas to evaluate the costs of the various configurations. Finally, we present the algorithm that determines the optimal configuration, and show its correctness.