In this Paper we show how a generic object-oriented database system can be extended into some domain-specific object-oriented database systems by building additional software layers on top of it. With each lower layer...
详细信息
In this Paper we show how a generic object-oriented database system can be extended into some domain-specific object-oriented database systems by building additional software layers on top of it. With each lower layer supporting the constructs and views provided by the upper layers, a high-level interface to the system is provided to the user, without having him/her to know about the details of the underlying database system. Specifically, the design of a spatial database kernel for GIS (Geographic Information System) applications which sits on top of a generic object-oriented database system is presented here. Bi-level data modelling approach is used as a methodology for its design and implementation. This data model consists at the top level the geographic object data model, and the geometric object data model at the bottom level The former consists of geographic objects, semantic spatial functions and non-spatial functions, whereas the geometric object data model consists of geometric objects and geometric functions. Geometric objects (e.g. polygons, lines, points) are the spatial representations of the geographic objects (e.g. countries, roads, rivers). Geometric functions directly support the implementation of the semantic spatial functions of the geographic object data model Furthermore, super-functions can be built using the existing functions in the kernel to build more specialized GIS domain-specific functions. Users can invoke these superfunctions, just like calling any other functions in the kernel, in writing GIS application programs that run on top of the kernel With this extensible set of application-oriented and domain-specific functions, a high-level query language called OFQL or the object-oriented Functional Query Language, is designed to allow user to pose spatial and non-spatial queries of a geographic nature. High-level query Processing and optimization issues, which are among the major concerns in the design of the spatial database kernel, are
Efficient process modeling is a key requirement for widespread use of model-based techniques for process design and operation in an industrial environment. It can only be met by advanced knowledge based software tools...
详细信息
Efficient process modeling is a key requirement for widespread use of model-based techniques for process design and operation in an industrial environment. It can only be met by advanced knowledge based software tools to cut down the effort for model development and maintenance. A suitably designed model base providing generic modeling knowledge as well as a validated family of models of varying degree of detail for a certain process is one of the main components of such a modeling system. This contribution focuses on the design of the model base which is treated as a database design problem. Proper process model structuring, formalization of the modeling knowledge by means of an object-oriented data model, and some implementational issues are considered.
This paper describes a design methodology for an objectoriented database, based on a semantic network. This approach is based on the assumption that semantic data models are more powerful and more easy to use than cu...
详细信息
ORION-2 is a commercially available, federated, object-oriented database management system designed and implemented at MCC. One major architectural innovation in ORION-2 is the coexistence of a shared database and a n...
详细信息
ORION-2 is a commercially available, federated, object-oriented database management system designed and implemented at MCC. One major architectural innovation in ORION-2 is the coexistence of a shared database and a number of private databases. The shared database is accessible to all authorized users of the system, while each private database is accessible to only the user who owns it. A distributed database system with a shared database and private databases for individual users is a natural architecture for data-intensive application environments on a network of workstations, notably computer-aided design and engineering systems. This paper discusses the benefits and limitations of such a system and explores the impact of such an architecture on the semantics and implementation of some of the key functions of a database system, notably queries, database schema, and versions. Although the issues are discussed in the context of an object-oriented data model, the results (at least significant portions thereof) are applicable to database systems supporting other data models.
databases based on object-oriented and semantic database models ('objectdatabases') represent significant advances over their record-based historical predecessors. In the context of general-purpose database m...
详细信息
databases based on object-oriented and semantic database models ('objectdatabases') represent significant advances over their record-based historical predecessors. In the context of general-purpose database management systems, the fundamentals of object database models are examined. Comparisons are made with record-based databases, as represented by relational database technology. The principal concepts underlying structurally object-oriented (semantic) database models are presented. Finally, a historical perspective on the evolution of object data-base technology is provided.
Hypermedia, object-oriented programming, and objectdatabases are new and promising trends in information processing. Behind each of these trends is a programming paradigm supporting a different approach in the design...
详细信息
Hypermedia, object-oriented programming, and objectdatabases are new and promising trends in information processing. Behind each of these trends is a programming paradigm supporting a different approach in the design and implementation of programs based on it. In this article, we consider possibilities to combine the most interesting features from these paradigms, and to apply the result to the development of knowledge-based systems. We call the combined paradigm hyperobjects. We have applied hyperobjects to an application performing knowledge-based condition monitoring and fault diagnosis on marine diesel engines. The application is called FAKS (Fault Avoidance Knowledge System). The prototype of the system was developed in the Technical Research Centre of Finland in cooperation with a Finnish diesel engine manufacturer Wartsila Diesel. Further development of FAKS, as a commercial product, have been made by Tiihonen Software Company Ltd and Wartsila Diesel. The first FAKS installation was delivered to a German rail ferry, Railship III, at the end of February 1990.
The issues of managing distributed applications are discussed, and a set of tools, the meta system, that solves some longstanding problems is presented. The Meta model of a distributed application is described. To mak...
详细信息
The issues of managing distributed applications are discussed, and a set of tools, the meta system, that solves some longstanding problems is presented. The Meta model of a distributed application is described. To make the discussion concrete, it is shown how NuMon, a seismological analysis system for monitoring compliance with nuclear test-ban treaties is managed within the Meta framework. The three steps entailed in using Meta are described. First the programmer instruments the application and its environment with sensors and actuators. The programmer then describes the application structure using the object-oriented data modeling facilities of the authors' high-level control language, Lomita. Finally, the programmer writes a control program referencing the data model. Meta's performance and real-time behavior are examined
Formalising and automating the software life-cycle processes are key factors in the improvement of software productivity. This paper describes the Project Master Database (PMDB) work, three generations of investigatio...
详细信息
Formalising and automating the software life-cycle processes are key factors in the improvement of software productivity. This paper describes the Project Master Database (PMDB) work, three generations of investigations into the modelling and encoding of software life-cycle processes;it briefly describes past activities and concentrates on more recent investigations. It presents an approach to software process modelling based on an object-based model called the PMDB + model, which includes project elements, relationships between those elements and behavioural descriptions of project life-cycle activities. An overview of the model is presented, together with examples to illustrate the application of the model to existing software processes. It also describes a prototyping exercise that implemented the PMDB + model in an object-oriented database management system. Key results of these investigations, the impact of process implementations on the architecture of environments, and lessons learnt from the exercises are described.
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 f...
详细信息
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
暂无评论