This paper describes the effect of schema evolution operations on the implementation of methods. The effect of these operations is captured as temporary inconsistencies. Extensions for handling these temporary inconsi...
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Automatically managing the evolutionary histories of both schema and data is an attractive feature for temporal object-oriented database management systems (OODBMS). It can make the temporal OODBMSs more suitable for ...
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object-oriented databases (OODBs) are believed to more naturally reflect the behavior and organization of real world objects. However, OODBs are mostly concerned about only the static aspects of object modeling. While...
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Subsumption between queries is a valuable information, e.g., for semantic query optimization. We approach the subsumption problem in the setting of object-oriented databases, and find that reasoning techniques from Ar...
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This paper describes an approach to the support of interface objects in an object-oriented database, and outlines some of the consequences of representing interface data as database objects. Existing architectures for...
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This paper concerns the problem of clustering objects onto units of secondary storage to minimise the number of I/O operations in database applications. We first investigate problems associated with most existing clus...
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An integrated approach to the management of computer-aided control engineering projects is described. It is shown that to exploit the benefits of object-oriented modelling and design an object-oriented database is req...
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An integrated approach to the management of computer-aided control engineering projects is described. It is shown that to exploit the benefits of object-oriented modelling and design an object-oriented database is required. A dynamic system object model is developed for use in project management using an object-oriented database. A complete description of the project management facilities is given, and the graphical user interface is described. A case study is used for illustration. Open architectures are considered and it is concluded that, together with object-oriented methods, these provide the possibility for exploiting the work described.
A knowledge base management system (KBMS) realises a combination of techniques found in database management systems and knowledge-based systems. At the data model and knowledge representation level, many systems of th...
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A knowledge base management system (KBMS) realises a combination of techniques found in database management systems and knowledge-based systems. At the data model and knowledge representation level, many systems of this kind constitute a marriage of the relational data model and the rule-based reasoning. Experience has shown that either approach is restricted in the way it can express the demanding information and knowledge structures required for applications like decision support systems. Two new technologies offer an exciting new integrated approach to knowledge management. object-oriented database management systems (OODBMS) provide an object model that supports powerful abstraction mechanisms to facilitate the modelling of highly structured information. Whereas case-based reasoning (CBR) systems are knowledge bases which organise their capabilities around a memory of past cases and the notion of similarity. Both types of system are built upon two fundamental concepts: 1) the retrieval of entities with potentially complex structure, called objects in the former, and cases in the latter type of system;2) the organisation of those entities in collections with common characteristics. In an OODBMS such collections are termed extents, and in CBR they are usually called categories. In either system, the conceptual meta notion to represent both, objects as well as extents, and cases as well as categories, is the class. Revolving around a Conceptual Case Class and extending a standard object model, this paper proposes a novel and general approach to represent case-knowledge and to build KBMSs. The work presented here is a spin-off the design of an object query language within the ESPRIT project Lynx.
The intermediate result cardinality - the number of objects satisfying a condition given in a query - is an important factor for estimating the cost of the query in query optimization. In this paper we show that an ob...
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The intermediate result cardinality - the number of objects satisfying a condition given in a query - is an important factor for estimating the cost of the query in query optimization. In this paper we show that an object-oriented query often involves partial participation of classes in a relationship. We then present a new technique for estimating the intermediate result cardinality in such a query. Partial participation has not been considered seriously in existing techniques. Since the proposed technique uses detailed statistics to accommodate partial participation, it estimates the intermediate result cardinality more accurately than existing ones. We also show that these statistics are easily obtained by using inherent properties of object-oriented databases.
In this study, we focus on the stability and behavior of three widely used clustering algorithms. Various correlation coefficients are computed to help us understand the sensitivity of object clustering. Surprisingly,...
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In this study, we focus on the stability and behavior of three widely used clustering algorithms. Various correlation coefficients are computed to help us understand the sensitivity of object clustering. Surprisingly, the results indicate that there is almost no difference among any clustering approach. Furthermore, all methods appear to be near stable. These findings tend to show that the clustering algorithms are independent of the way objects are inherently clustered.
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