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.     

Applications of object-oriented technology to the integration of heterogeneous database systems

The object-oriented paradigm has several features that facilitate the integration of heterogeneous data management systems. One of the main problems in the integration is to provide users with the same data model and language to access very different systems. This problem exists in all kinds of distributed heterogeneous data management systems, independently from their integration architecture (like classical distributed databases, federated databases, multidatabases). This paper shows that the use of an object-oriented data model for building a uniform view of several databases can greatly simplify this task, and actually extends the scope of integration towards two directions. The first concerns the integration of data management systems to which traditional integration techniques, based on mappings among data models, cannot be applied. The second direction moves the goal of integration to re-using not only data but to re-using data and application software using these data. In the paper we also briefly discuss some requirements for an object-oriented integrated platform. Recommended by: F. Manola     

一种并发面向对象同步模型研究

同步是并发语言的一个重要特征,然而在面向对象的框架下,同步约束的存在可能导致不期望的方法的重定义.基于并发面向对象规约语言VDM++(Vienna development method)的两种同步机制,提出一种适合于并发面向对象广谱规约语言的同步模型-卫式路径结构.它不但可以支持一般代码的复用,而且可以全方位地支持对同步代码的复用.     

面向对象软件度量自动化参考模型MOOP

评估软件质量涉及到定性和定量两个方面。在定量的度量方面,要考虑两个问题,一是度量什么,二是如何度量。面向对象技术的新特点给软件度量提出了新的要求。本文提出了一种针对面向对象程序分析的度量自动化参考模型MOOP,该模型采用三层结构：翻译层、表示层、分析层,具有可重定编译前端、中间表示与语言无关、度量集可定制等优点。基于MOOP参考模型,我们设计了一种面向对象度量自动化系统MOOP－Kit。     

A deductive object-oriented database system for situated inferencein law

Deductive object-oriented databases and situation theory are two important areas of research in the fields of databases and of linguistics. “AI and law” is a new field attracting both AI researchers and legal practitioners. Our research brings together the former two fields with the aim of designing knowledge applications in the latter. This is achieved through a formal model for legal reasoning, 𝒮ℳ (“Situation-theoretic Model”), and a deductive object-oriented database system, 𝒬𝒰ℐ𝒳𝒪𝒯ℰ. The purpose of this paper is to introduce the key features of this formal model, based on situation theory, and to describe how this database system can implement this abstract model for complex legal reasoning applications. Concrete examples from legal precedents are used to illustrate these advanced features     

应用于GIS系统的多级时序数据模型

GIS中地理对象生命期的表示以及动态信息的表达需要时序数据的支持。一些基于关系数据库的GIS系统在实现时序数据时形成大量的数据冗余且难以维护数据的一致性。针对这些问题，结合GIS中对于时序精度的不同需求，提出了一种多级别时序数据模型。讨论了时间的相关概念，定义了一套基本的时间对象类型，提出并解释了对象级和属性级时序数据模型。基于面向对象数据库的实现显示，模型不仅满足了GIS中支持时序数据的需求，同时在存储开销、数据一致性等方面具有显著的优点。     

Approaches to deductive object-oriented databases

The paper is concerned with the problem of combining deductive and object-oriented features to produce a deductive object-oriented database system which is comparable to those currently available under the relational view of data modelling not only in its functionality but also in the techniques employed in its construction and use. Under this assumption, the kinds of issues that have to be tackled for a similar research strategy to produce comparable results are highlighted. The authors motivate their terms of comparison, characterize three broad approaches to deductive object-oriented databases and introduce the notion of language convergence to help in the characterization of some shortcomings that have been perceived in them. Three proposals that have come to light in the past three years are looked into in some detail, in so far as they exemplify some of the positions in the space of choices defined. The main contribution of the paper is towards a characterization of the language convergence property of deductive database languages which has a key role in addressing critiques of the deductive and object-oriented database research enterprise. A basic familiarity with notions from deductive databases and from object-oriented databases is assumed.     

A semantic model of confinement and Locality theorem

Confinement is required in object-oriented programming in order to protect sensitive object references. Recently a range of confinement schemes have been proposed to achieve object encapsulation by defining static type systems, but unavoidably, with strong restrictions. On the other hand, no similarity in concepts makes assessing of these schemes a difficulty. We build in this paper a semantic model for confinement in μJava, a subset of sequential Java that offers most object-oriented features. This model has limited restriction for programs. From a semantic view, confinement is defined with respect to a given context that specifies partition of the object pool and confinement constraint among them. Moreover, we present the main Locality theorem for checking well confinement of programs locally. By applying this theorem, we have solved a security breach problem from Java JDK 1.1.1, and furthermore, proved the soundness of two widely used confinement schemes: confined types and ownership types.     

JavaScript面向对象编程探析

通过JavaScript程序代码实例,探析如何在网站开发中使用JavaScript对象进行编程,JavaScript的对象有两种一种可被称为普通对象,另一种被称为方法对象,这和其它的面向对象语言有所不同,在文章中用实例代码对此进行了说明和探析,并且,把自己在实际项目中使用的几种JavaScript对象编程方法在文章中进行了举例说明。     

一种快速生成面向对象模型的方法

通常直接从错综复杂的现实世界抽象出面向对象模型有许多困难。文章提出了一种从实体/联系模型转换为面向对象模型的间接方法。文章中重点讨论了面向对象方法的原理以及转换算法。实践证明,该种算法是有效的。     

Developing GIS Applications with Objects: A Design Patterns Approach

In this paper we present an object-oriented approach for designing GIS applications; it combines well known software engineering practices with the use of design patterns as a conceptual tool to cope with recurrent problems appearing in the GIS domain. Our approach allows the designer to decouple the conceptual definition of application objects from their spatial representation. In this way, GIS applications can evolve smoothly, because maintenance is achieved by focusing on different concerns at different times. We show that our approach is also useful to support spatial features in conventional applications built with object-oriented technology. The structure of this paper is as follows: We first introduce design patterns, an efficient strategy to record design experience; then we discuss the most common design problems a developer of GIS applications must face. The core of our method is then presented by explaining how the use of decorators helps in extending objects to incorporate spatial attributes and behavior. Next, we analyze some recurrent design problems in the GIS domain and present some new patterns addressing those problems. Some further work is finally discussed.     

Extending a deductive object-oriented database system with spatial data handling facilities

This paper describes the integration of a spatial data-handling component with the ROCK & ROLL deductive object-oriented database system. The extended ROCK & ROLL system provides much more comprehensive and better integrated database programming facilities than other candidate platforms for spatial information systems. The extended system serves developers with an intuitive, expressive, formally defined collection of spatial data types as primitive types whose operations have state-of-the-art computational complexity. The integration of these types with the object-oriented modelling, imperative programming and deductive querying facilities of ROCK & ROLL makes available a comprehensive and integrated suite of complementary mechanisms for the development of spatial information systems. The paper also provides preliminary benchmark results which indicate that kernel-support for spatial data handling does yield performance gains and that the extended ROCK & ROLL system compares well with a specialist geographic information system and two widely known extensible database systems when the latter are extended with spatial data handling facilities.     

The Pegasus heterogeneous multidatabase system

Pegasus, a heterogeneous multidatabase management system that responds to the need for effective access and management of shared data across in a wide range of applications, is described. Pegasus provides facilities for multidatabase applications to access and manipulate multipole autonomous heterogeneous distributed object-oriented relational, and other information systems through a uniform interface. It is a complete data management system that integrates various native and local databases. Pegasus takes advantage of object-oriented data modeling and programming capabilities. It uses both type and function abstractions to deal with mapping and integration problems. Function implementation can be defined in an underlying database language or a programming language. Data abstraction and encapsulation facilities in the Pegasus object model provide an extensible framework for dealing with various kinds of heterogeneities in the traditional database systems and nontraditional data sources     

Autonomous objects: A natural model for complex applications

Object-oriented database systems are emerging as the next generation DBMSs for advanced applications, e.g., VLSI design, mechanical CAD/CAM, software engineering, etc. However, a close analysis indicates that the requirements imposed by these application domains cannot be met by an object-oriented model that relies purely onpassive objects. In this work we go beyond the conventionalsingle-thread-of-control paradigm of passive object models and propose a model ofactive objects which can autonomously initiate responses to environmental changes.Autonomous objects cooperate with each other by synchronous orasynchronous message passing—giving rise to themultiple-thread-of-control in such an environment. It is shown howevents—to which active objects react—can be incorporated into this model. We propose a nondeterministic computational model for the individual active objects that allows the autonomous reaction upon events. We show that this very sparse extension to an object-oriented model gives rise to several high-level features which can be controlled by events. The object-oriented paradigm allows one to isolate the rules according to which events are being raised. This leads to a potentially rather efficient execution model compared to existing relational concepts, which are typically globally-defined event trigger mechanisms.     

基于Linux的消息驱动Socket模型

在Linux下进行网络编程时通常使用Socket．Linux系统的输入输出模型主要有4种：阻塞式，非阻塞式，多路复用和信号驱动。这4种输入输出模型均具有一定的局限性，使得在Linux下的网络编程颇不方便。该文设计了一种面向对象、消息驱动的Socket摸型。     

高层建筑结构CAD系统的数据模式

用面向对象的分析方法对高层建筑结构CAD系统进行了分析,通过对基本对象及其之间关系,作用的抽象,运用面向对象的设计方法建立了高层建筑 基本对象模型,采用面向对象技术和关系数据库相结合的方法,构造和初步建立了高层建筑结构的工程数据库,能够较好地解决高层建筑结构集成化CAD系统的数据组织和管理问题。     

CIMS信息集成平台中的数据模型

为了满足ＣＩＭＳ环境中信息集成的需求。本文为信息集成平台设计了一种具有集成功能的面向对象的数据模型ＩＣＯＭ．ＩＣＯＭ数据模型不仅具有行为的封装与重载，继承与继承、行为的提炼与迟后联编和多态性等面向对象的特征，而且还能够很好解决集成过程中出现的各类冲突，即模式冲突与数据冲突。     

Java芯片操作系统的模型和实现

提出的Java芯片操作系统是一个基于Java芯片系统的、针对嵌入式应用的面向对象操作系统.它由服务器、内核和转换层等3种组件构成.这些组件的抽象特征构成了其基本框架.特定组件继承了上述的特征,并进行特化.与经典操作系统相比,该操作系统更容易开发和维护,并具有更好的可伸缩性、代码的可重用性和可移植性.介绍了该操作系统的结构、运行模型以及实现技术,并与相关的工作进行了比较.     

Implementing associations: UML 2.0 to Java 5

A significant current software engineering problem is the conceptual mismatch between the abstract concept of an association as found in modelling languages such as UML and the lower level expressive facilities available in object-oriented languages such as Java. This paper introduces some code generation patterns that aid the production of Java based implementations from UML models. The work is motivated by a project to construct model driven development tools in support of the construction of embedded systems. This involves the specification and implementation of a number of meta-models (or models of languages). Many current UML oriented tools provide code generation facilities, in particular the generation of object-oriented code from class diagrams. However, many of the more complex aspects of class diagrams, such as qualified associations are not supported. In addition, several concepts introduced in UML version 2.0 are also not supported.The aim of the work presented in this paper is to develop a number of code generation patterns that allow us to support the automatic generation of Java code from UML class diagrams that support these new and complex association concepts. These patterns significantly improve the code generation abilities of UML tools, providing a useful automation facility that bridges the gap between the concept of an association and lower level object-oriented programming languages.