Reorganization of objects in an objectdatabases is an important component of several operations like compaction, clustering, and schema evolution. The high availability requirements (24 X 7 operation) of certain appl...
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object models have an important part to play in the future of database systems, but progress is hampered by lack of agreement on their essential characteristics. Strong constraints on the design of a common model are ...
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The development of techniques for supporting incremental maintenance of materialized views has been an active research area for over twenty years. However, although there has been much research on methods and algorith...
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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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The ODMG standard is a proposal to solve one of the main drawbacks of object-oriented databases (OODBs): the lack of a standard for object definition and management. Nevertheless, this standard does not offer a soluti...
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The ODMG standard is a proposal to solve one of the main drawbacks of object-oriented databases (OODBs): the lack of a standard for object definition and management. Nevertheless, this standard does not offer a solution for another lack of OODBs, related to the definition of external schemas. In this work, a methodology to define external schemas in ODMG databases is put forward. This methodology proposes a solution for the tasks involved-specification, closure and generation of external schemas-introducing also an extension of ODMG metadata to enable the definition of external schemas in ODMG databases.
Software processes are long-lived entities. Careful design and thorough validation of software process models are necessary to ensure the quality of the process. They do not prevent, however, process models from under...
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Software processes are long-lived entities. Careful design and thorough validation of software process models are necessary to ensure the quality of the process. They do not prevent, however, process models from undergoing change. Change requests may occur in the context of reuse, i.e., statically, in order to support software process model customization. They can also occur dynamically, while software process models are being executed, in order to support timely reaction as data are gathered from the field during process enactment. In this paper, we discuss the mechanisms a process language should possess in order to support changes. We illustrate the solution adopted in the context of the SPADE environment and discuss how the proposed mechanisms can be used to model different policies for changing a software process model.
In Cyberspace, realized by the Electronic Super-highway and multimedia techniques, persons will be represented by 'things' (so called 'alter-egos') grown out of the traditional social security numbers....
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In Cyberspace, realized by the Electronic Super-highway and multimedia techniques, persons will be represented by 'things' (so called 'alter-egos') grown out of the traditional social security numbers. In this paper we will study how the object-oriented methodology can help in designing these inhabitants. By using an interesting example, namely home banking, we will study the problem of security and privacy, in general: access protection, in this world. New in this paper is the combination of Cyberspace, Alter-ego objects representing its inhabitants and protection problems. In particular, we will demonstrate the need for knowledge based capabilities for handling the complex security features which are required in the Cyberspace world.
In this paper, we focus on conceptual data modeling and logical database modeling of fuzzy information. The IFO data model is extended with fuzzy set theory to cope with imperfect as well as with complex objects in th...
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In this paper, we focus on conceptual data modeling and logical database modeling of fuzzy information. The IFO data model is extended with fuzzy set theory to cope with imperfect as well as with complex objects in the real world at a conceptual level. Concerning the logical database modeling of fuzzy information, we focus on the object-oriented database model. Some major notions in the object-oriented databases such as objects, classes, objects-classes relationships, supertype/subtype, and multiple inheritances are extended under fuzzy information environment, and a generic model for fuzzy object-oriented databases is developed. In particular, we develop the formal approach to mapping a fuzzy 1170 (IF2O) model to a fuzzy object-oriented database schema. Therefore, one can conduct the conceptual design of a database model with fuzzy information and then transform it into the logical database model.
Next generation information system applications require powerful and intelligent information management that necessitates an efficient interaction between database and knowledge base technologies. It is also important...
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Next generation information system applications require powerful and intelligent information management that necessitates an efficient interaction between database and knowledge base technologies. It is also important for these applications to incorporate uncertainty in data objects, in integrity constraints, and/or in application. In this study, we propose an intelligent object-oriented database architecture, IFOOD, which permits the flexible modeling and querying of complex data and knowledge including uncertainty with powerful retrieval capability.
Presented in this paper is a model that utilizes existing materialized views to handle a wide range of complex selection-based queries, including linear recursive queries. Such queries are complex because it is almost...
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Presented in this paper is a model that utilizes existing materialized views to handle a wide range of complex selection-based queries, including linear recursive queries. Such queries are complex because it is almost impossible for naive users to predict the formulation of their predicate expressions. object variables bound to objects in the result of a query are allowed to appear in the predicate of that query. Also, the predicate definition is extended to make it possible to have in the output only a subset of the objects from the actual result of a linear recursive query. We introduce an algorithm that utilizes existing materialized views in answering queries covered by the presented model. The presented model has been implemented as a part of our object-oriented database management system prototype. (C) 1999 Elsevier Science Inc. All rights reserved.
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