一个演绎对象数据库SD-DOOD的设计与实现

通过探寻面向对象数据库与知识库技术相结合的途径,研究演绎对象数据库系统实现的关键技术。以基于演绎数据库系统SD-DDBS,设计实现了一个演绎对象数据库系统原型SD-DOOD。系统支持类、类层次、对象、属性、方法、继承和封装等面向对象数据库系统的核心概念,支持演绎对象等演绎数据库的概念,提供了图形用户接口(GUI),便于用户进行创建、查询等操作。     

Index organizations for object-oriented database systems

We present an indexing technique providing support for queries involving complex, nested objects and inheritance hierarchies. This technique is compared with two techniques obtained from more traditional organizations. The three techniques are evaluated using an analytical cost model. The discussion is cast in the framework of object-oriented databases. However, results are applicable to data management systems characterized by features such as complex objects and inheritance hierarchies     

Asymmetrical nonlinear impedance control for dual robotic machining of thin-walled workpieces

Impedance control is to provide stable tracking by regulating the impedance response of a robot. In this paper, an asymmetrical nonlinear impedance control (ANIC) is proposed for a dual robotic machining system. The symmetrical linear impedance control (SLIC) is also analyzed as a comparison study. We compared two controllers in terms of the stability and the sensitivity property of the grinding force, as well as the trajectory design. The main advantage of the ANIC is that the grinding force is robust to the environmental disturbances and the variation in thickness of workpieces. In contrast to the traditional control concept, which is devoted to compensate the nonlinear effect of the original system, our design philosophy is to increase the system robustness by introducing an artificial nonlinearity to the system. As a result, the dual robotic system acts as variable stiffness actors to adapt the variation in the thickness of workpieces. Grinding experiments are conducted in the dual robotic machining test rig for both workpieces with the uniform and varied thickness. The experimental results show that the dual robotic system with the ANIC can achieve better grinding quality.     

Decomposition of object-oriented database schemas

We specify a data model with object-oriented and logic-oriented features. The model is based on F-logic. For this model, we study a decomposition of a class, the counterpart to the well-known decomposition of a relation scheme under functional dependencies. For this decomposition of a class, the transformation pivoting is used. Pivoting transplants some attributes of the class to a newly generated class. This new class is a subclass of the result class of the so-called pivot attribute. The pivot attribute maintains the link between the original class and the new subclass. We identify the conditions under which input and output of pivoting are equivalent. Additionally, we show under which conditions a schema with functional dependencies can be recursively transformed into an equivalent one without non-key functional dependencies.     

A Prototypical 3D Graphical Visualizer for Object-Oriented Systems

is paper describes a framework for visualizing object-oriented systems within a 3D interactive environment.The 3D visualizer represents the structure of a program as Cylinder Net that simultaneously specifies two relationships between objects within 3D virtual space.Additionally,it represents additional relationships on demand when objects are moved into local focus.The 3D visualizer is implemented using a 3D graphics toolkit,TOAST,that implements 3D Widgets 3D graphics to ease the programming task for 3D visualization.     

面向对象软件度量的3D可视化方法

软件可视化是指利用印刷、图形、动画以及其它图形或摄影技术提高人们对软件的理解的技术.度量可视化是软件可视化研究的分支之一,它是把度量数据与可视化的图形结合来表示软件的结构.现有的度量可视化方法存在的不足是所能表示的度量指标等属性太少,表示出来的信息不够全面.为了表示更多的属性信息,提出了一种新的面向对象软件度量的3D可视化方法,利用组合图形表示软件实体(如类、方法等),使得所表示的属性数量加倍,从而更有利于对软件的理解和分析.开发出可视化工具M3DTool证明了该方法的有效性.     

数据库系统设计中的面向对象技术研究

基于面向对象技术的基本思想和开发过程,介绍了面向对象技术的实现方法.结合具体实例对面向对象技术在数据库系统结构设计和详细设计中的应用进行了详细的探讨,利用面向对象的数据库系统分析和设计方法,使用UML工具建立了具体的对象模型,给出了一种比较通用的数据库系统开发模式.使用该模式设计的系统重用性好,且易于维护,从而有效提高了数据库系统的开发质量.     

An object-oriented multimedia database system for a news-on-demand application

We describe the design of a multimedia database management system for a distributed news-on-demand multimedia information system. News-on-demand is an application that uses broadband network services to deliver news articles to subscribers in the form of multimedia documents. Different news providers insert articles into the database, which are then accessed by users remotely, over a broadband, asynchronous transfer-mode (ATM) network. The particulars of our design are an object-oriented approach and strict adherence to international standards, in particular the Standard Generalized Mark-up Language (SGML) and Hy-Time. The multimedia database system has a visual query facility, which is also described in this paper. The visual query interface provides three major facilities for end users: presentation, navigation, and querying of multimedia news documents. The main focus, however, is the querying of multimedia objects stored in the database.     

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     

An object-oriented Monte Carlo simulator for 3D cylindrical positron tomographs

Monte Carlo simulation is a very powerful tool in understanding performances of positron tomographs as well as in assessing image reconstruction algorithms and their implementations. We present an object-oriented Monte Carlo simulator developed for 3D positron tomography. Results from phantom simulation studies including absorption and scattering of the photons in the field-of-view are presented. Scatter fractions determined from these studies are in good agreement with measured scatter fractions published in the literature. Limitations and future prospects are discussed.     

Formalization of object-oriented database model with rules

The paper investigates knowledge representation in an object-oriented database management system first within the data model with rules and second in the computational model by using logic. Issues of structure, integrity, and retrieval are focused on. The proposed system provides object-oriented concepts for describing complex structured data, rules for expressing object-dependent constraints and object associations, and, finally, logic for inference and retrieval.     

Design and Implementation of a Concurrency Control Mechanism in an Object-Oriented Database System

This paper presents a practical concurrency control mechanism-Object-Locking in OODBMS.Object-Locking can schedule transactions,each of them can be considered as a sequence of high level operations defined on classes.By the properties of parallelity and commutativity between high level operations,proper lock modes for each operation are designed and the compatibility matrix is constructed.Wiht these lock modes,phantoms are kept away from databases and a high degree of concurrency is achieved.     

A method for the definition of integrity constraints in object-oriented conceptual modeling languages

We propose a new method that eases the definition of integrity constraints in object-oriented conceptual modeling languages. The essence of the method is to represent constraints by special operations that we call constraint operations. The formal specification of these operations is the definition of the corresponding constraints. The method allows the specialization of constraints and the definition of exceptions. The main application of the method is for static constraints. However, a variant of it can also be applied for creation-time and deletion-time constraints, two particular classes of temporal constraints. The method can be adapted to any object-oriented language, and we show its adaptation to the UML. We also show that our method has several advantages over existing methods.     

基于Quest3D的采煤机虚拟培训系统设计

针对目前采煤机培训方式不能立体化多角度地展示采煤机操作过程的问题,设计了基于Quest3D的采煤机虚拟培训系统。该系统由下位机和上位机组成,二者通过RS232协议通信。下位机用来模拟采煤机的控制平台,以STC89C52单片机为核心的控制电路实现对外部操作信号的接收、处理和传输。上位机使用3DMax建模软件创建虚拟场景所需的模型,通过Quest3D三维引擎开发平台完成虚拟场景搭建,并依据下位机的命令对模型进行控制。该系统实现了采煤机虚拟培训功能,缩短了培训周期,降低了培训成本。     

数据库操作题自动阅卷的设计与实现

为克服人工阅卷的诸多困难,给出了一个对数据库操作题自动阅卷的设计方案,该方案以试题的组织形式和录入技术为基础,设计了供阅卷程序识别的形式语言,覆盖了数据库操作题的主要内容,作为山西省计算机应用能力考核系统的子系统,该方案已投入使用。     

A method for the definition of integrity constraints in object-oriented conceptual modeling languages

We propose a new method that eases the definition of integrity constraints in object-oriented conceptual modeling languages. The essence of the method is to represent constraints by special operations that we call constraint operations. The formal specification of these operations is the definition of the corresponding constraints. The method allows the specialization of constraints and the definition of exceptions. The main application of the method is for static constraints. However, a variant of it can also be applied for creation-time and deletion-time constraints, two particular classes of temporal constraints. The method can be adapted to any object-oriented language, and we show its adaptation to the UML. We also show that our method has several advantages over existing methods.     

面向对象数据库的隐授权安全机制研究

面向对象数据库（OODB）独特的数据组织与操纵原理,决定了其具有不同于传统关系数据库的安全保护和授权模式。介绍了OODB安全授权机制特点,通过对OODB安全授权模式的主体、客体及访问方式三个层次的讨论,重点对授权检验流程及这三个层次上的隐授权机制进行了研究,通过尝试在实例中结合其他几种授权方式的应用,表明了隐授权机制的有效性和灵活性。     

An object-oriented database management system for computer-aided design of tall buildings

An effective database and database management system is the key to the success of an integrated approach to software engineering applications in general, and Computer-Aided Design (CAD) for structural applications in particular. Due to the inherent nature of CAD data such as dynamic modeling, a wide range of data types, large data volume, etc., the traditional database models, such as hierarchical, network and relational models, are unable to handle the aforementioned applications satisfactorily. An object-oriented data modeling is known to be the most effective approach. However, many of the commercial object-oriented databases are designed for information management, and they are inadequate for CAD application due to the different features of the object-hierarchy and varying data management objectives during the design cycles. This paper presents a hierarchical index-based object-oriented database management model for CAD applications. To deal with the object hierarchy encountered in CAD for the design of tall buildings, the proposed database consists of several salient features: a hierarchical object model, its related storage structure, a data dictionary, a class factory and an index system. The proposed database management model has been implemented into an integrated CAD system for design application of tall buildings.     

面向对象数据库中数据字典实现的一种方法

面向对象数据库支持复杂的数据类型,语义贴近现实,因而有广泛的应用前景.数据字典是数据库的骨架,因此数据字典的建立至关重要.通过对面向对象数据库和关系数据库中数据字典结构的研究,建立和实现了面向对象数据字典;用十字链表数据结构存储数据字典,并给出了算法.用十字链表的方法存储数据字典结构清晰,插入和查询方便.