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9th International Conference on Information and Knowledge Management (CIKM 2000)

作者： Cho, Wan-Sup Han, Wook-Shin Hong, Ki-Hyung Whang, Kyu-Young Dept. of MIS Chungbuk National University Korea Republic of Korea Republic of Dept. of Computer Science Sungshin Women's University Korea Republic of

ISBN: (纸本)9781581133202

A search condition in object-oriented queries consists of nested predicates, each of which is a predicate on a path expression. In this paper, we present a new selectivity estimation technique for nested predicates. Selectivity of a nested predicate, nested selectivity, is defined as the ratio of the number of qualified objects of the starting class in the path expression to the total number of objects of the class. The new technique takes into account the effects of direct representation of many-to-many relationships. Many-to-many relationships frequently occur in object-oriented databases, but have not been properly handled in conventional selectivity estimation techniques. For many-to-many relationships, we generalize the block-hit function originally proposed by B. Yao allowing the cases where one object belongs to more than one block. The most significant advantage of our technique is that the accuracy of the estimation is far enhanced with only a small additional overhead. We present an efficient method for obtaining the statistical information that is needed for our estimation technique. We analyze the accuracy of our estimation technique and compare the result with those of conventional ones. The experimental result shows there is a significant deviation in the estimation obtained by conventional ones, confirming the advantage of our technique. © ACM 2000.

关键词： object-oriented databases

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Explicit modeling of the semantics of large multi-layered object-oriented databases 19

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19th International Conference on Conceptual Modeling, ER 2000

作者： Koch, Christoph Kovacs, Zsolt Le Goff, Jean-Marie McClatchey, Richard Petta, Paolo Solomonides, Tony EP Division CERN Geneva 23CH-1211 Switzerland Centre for Complex Cooperative Systems Univ. West of England BristolBS16 1QY United Kingdom Austrian Research Institute for Artificial Intelligence Schottengasse 3 ViennaA-1010 Austria

ISBN: (纸本)9783540410720

Description-driven systems based on meta-objects are an increasingly popular way to handle complexity in large-scale object- oriented database applications. Such systems facilitate the management of large amounts of data and provide a means to avoid database schema evolution in many settings. Unfortunately, the description-driven approach leads to a loss of simplicity of the schema, and additional software behaviour is required for the management of dependencies, description relationships, and other Design Patterns that recur across the schema. This leads to redundant implementations of software that cannot be handled by using a framework-based approach. This paper presents an approach to address this problem which is based on the concept of an ontology of Design Patterns. Such an ontology allows the convenient separation of the structure and the semantics of database schemata. Through that, reusable software can be produced which separates application behaviour from the database schema. © Springer-Verlag Berlin Heidelberg 2000.

关键词： object-oriented databases

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Change management for a temporal versioned object-oriented database

Change management for a temporal versioned object-oriented d...

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21st International Conference on Conceptual Modeling, ER 2002 held in conjunction with 2nd International Workshop on Evolution and Change in Data Management, ECDM 2002, ER/IFIP 8.1 Workshop on Conceptual Modelling Approaches to Mobile Information Systems Development, MobIMod 2002, International Workshop on Conceptual Modeling Quality, IWCMQ 2002 and 3rd International Joint Workshop on Conceptual Modeling Approaches for E-business: a Web Service Perspective, eCOMO 2002

作者： de Matos Galante, Renata Edelweiss, Nina dos Santos, Clesio Saraiva Instituto de Informática Universidade Federal do Rio Grande do Sul Brazil

ISBN: (纸本)3540202552

In this paper, we propose a schema versioning mechanism to manage the schema evolution in temporal object-oriented databases. The schema evolution management uses an object-oriented data model that supports temporal features and versions definition - the Temporal Versions Model - TVM. One interesting feature of our proposal is that TVM is used to control not only the schema versioning, but also the storage of extensional database and propagation of the changes performed on the objects. The extensional data level supports integration with the existing database, allowing the maintenance of conventional and temporal versioned objects. The instance propagation approach is proposed through the specification of propagation and conversion functions. These functions assure the correct instance propagation and allow the user to handle all instances consistently in both backward and forward schema versions. Finally, the initial requirements concerning data management in the temporal versioning environment, during schema evolution, are presented. © Springer-Verlag Berlin Heidelberg 2003.

关键词： object-oriented databases

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A sequence-based object-oriented model for video databases

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MULTIMEDIA TOOLS AND APPLICATIONS 2002年第3期18卷 249-277页

作者： Dumas, M Lozano, R Fauvet, MC Martin, H Scholl, PC Queensland Univ Technol Brisbane Qld 4005 Australia Inst Tecnol Monterrey Mexico City DF Mexico Univ Grenoble LSR IMAG F-38402 St Martin Dheres France

Structuration, annotation and composition are amidst the most crucial modeling issues that video editing and querying in the context of a database entail. In this paper, we propose a sequence-based, object-oriented data model that addresses them in an unified, yet orthogonal way. Thanks to this orthogonality, the interactions between these three aspects are properly captured, i.e., annotations may be attached to any level of video structuration, and all the composition operators preserve the structurations and annotations of the argument videos. We also propose to query both the structuration and the annotations of videos using an extension of ODMG's OQL which integrates a set of algebraic operators on sequences. The overall proposal is formalized and implemented on top of an object-oriented DBMS.

关键词： video databases temporal databases object-oriented databases ODMG

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Mobiscope: A scalable spatial discovery service for mobile network resources

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4th International Conference on Mobile Data Management, MDM 2003

作者： Denny, Matthew Franklin, Michael J. Castro, Paul Purakayastha, Apratim U.C. Berkeley BerkeleyCA United States IBM T.J. Watson Research Center HawthorneNY United States

ISBN: (纸本)3540003932

Mobiscope is a discovery service where clients submit longrunning queries to continually find sets of moving network resources within a specified area. As in moving object databases (MODBMSs), moving resources advertise their positions as functions over time. When Mobiscope receives a query, it runs the query statically against advertisements (ads) that are currently cached by Mobiscope, and then continuously over ads that Mobiscope receives subsequently. For scalability, Mobiscope distributes the workload to multiple nodes by spatial coordinates. Application-level routing protocols based on geography ensure that all queries find all matching resources on any node without significant processing overhead. Simulation results indicate that Mobiscope scales well, even under workloads that stress Mobiscope’s distribution model. © Springer-Verlag Berlin Heidelberg 2003.

关键词： object-oriented databases

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On-line discovery of dense areas in spatio-temporal databases

On-line discovery of dense areas in spatio-temporal database...

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8th International Symposium on Spatial and Temporal databases, SSTD 2003

作者： Hadjieleftheriou, Marios Kollios, George Gunopulos, Dimitrios Tsotras, Vassilis J. Computer Science Department University of California Riverside United States Computer Science Department Boston University United States

ISBN: (纸本)3540405356

Moving object databases have received considerable attention recently. Previous work has concentrated mainly on modeling and indexing problems, as well as query selectivity estimation. Here we introduce a novel problem, that of addressing density-based queries in the spatio-temporal domain. For example: "Find all regions that will contain more than 500 objects, ten minutes from now". The user may also be interested in finding the time period (interval) that the query answer remains valid. We formally define a new class of density-based queries and give approximate, on-line techniques that answer them efficiently. Typically the threshold above which a region is considered to be dense is part of the query. The difficulty of the problem lies in the fact that the spatial and temporal predicates are not specified by the query. The techniques we introduce find all candidate dense regions at any time in the future. To make them more scalable we subdivide the spatial universe using a grid and limit queries within a pre-specified time horizon. Finally, we validate our approaches with a thorough experimental evaluation. © Springer-Verlag Berlin Heidelberg 2003.

关键词： object-oriented databases

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An object-oriented approach for transformation of spatial data from relational database to object-oriented database

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6th International Conference on Asian Digital Libraries, ICADL 2003

作者： Kiong, Siew Teck Chai, Wang Yin Universiti Malaysia Sarawak Kota SamarahanSarawak94300 Malaysia

ISBN: (纸本)9783540206088

Classical data models like the relational data models have proven to have limitations in modeling spatial data in many aspects. In the latest computer technology, object-oriented database technology extends support for the complex data types to deal with the today’s complex applications. There are various attempts in integrating the two models to exploit the strengths of these two models to develop a flexible environment for the complex applications. However, these new data models such as extended and extensible relational database technology still suffer from various problems. In view of this, the perusal in this study is to develop an approach which constitutes the transformation system to transform spatial data fully from the relational database to the object-oriented database. The approach pursued is an objectoriented approach whereby the development of the transformation system is achieved through the applications of object-oriented features such as data abstraction, inheritance, polymorphism and behavior modeling. This involves the structural and the behavioral design of the transformation system around the objects. © Springer-Verlag Berlin Heidelberg 2003.

关键词： object-oriented databases

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Extraction of object-oriented schemas from existing relational databases: A form-driven approach

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INFORMATICA 2002年第1期13卷 47-72页

作者： Malki, M Flory, A Rahmouni, MK Univ Djillali Liabes Sidi Bel Abbes Dept Comp Sci Sidi Bel Abbes Algeria INSA Lyon LISI Lyon France Univ Oran Dept Comp Sci Oran Algeria

In this paper, we present our Form-driven approach for reverse engineering of relationa databases. This methodology uses the information extracted from both form structure and instances as a database reverse engineering input using an interaction with a user. Through a combination of forms structures and data instances analysis, forms relational sub-schemas and their constraints are derived. These relational sub-schemas are mapped to object sub-schemas, which will be merging into global object-oriented schema that presents the whole underlying databases. The resulting global object-oriented schema must be validated as a rich and correct representation of the application domain.

关键词： relational databases reverse engineering object-oriented databases forms integration validation

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Applying UML to a new model for transformation of spatial data from relational database to object-oriented database

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6th International Conference on Asian Digital Libraries, ICADL 2003

作者： Kiong, Siew Teck Chai, Wang Yin Universiti Malaysia Sarawak Kota SamarahanSarawak94300 Malaysia

ISBN: (纸本)9783540206088

The design of the new model for the full transformation of the spatial data from relational database to object-oriented database is performed in object oriented environment using the object-oriented analysis and design tools. It consists of the static modeling of the software components of the new model. It involves the creation of the design class diagram, which indicates all the classes and the relationships identified in the new model. In addition, it couples the dynamic modeling of the software components which produces an active database in completing the data transformation and application transformation processes. This has contributed significantly in eliminating the prevailing problem of "impedance mismatch" in the database technology. The dynamic modeling involves the trigger mechanism that interacts among the software objects to accomplish the transformation. The application of UML enhances the design of the new model especially in the dynamic modeling of the active database. The artifacts created in this design phase by applying UML provide a significant degree of the information necessary to implement the transformation system. Besides, UML creates an easily reusable, extensible and maintainable design of the new model especially in the distributed computing environment. © Springer-Verlag Berlin Heidelberg 2003

关键词： object-oriented databases

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Enhancing OODB semantics to support browsing in an OODB vocabulary representation

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CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE 2003年第9期15卷 845-869页

作者： Liu, LM Geller, J Perl, Y New Jersey Inst Technol Dept Comp Sci Newark NJ 07102 USA Chung Yuan Christian Univ Dept Math Appl Chungli Taiwan

In previous work, we have modeled a vocabulary given as a semantic network by an object-oriented database (OODB). The OODB schema thus obtained provides a compact abstract view of the vocabulary. This enables the fast traversal of the vocabulary by a user. In the semantic network vocabulary, the IS-A relationships express the specialization hierarchy. In our OODB modeling of the vocabulary, the SUBCLASS relationship expresses the specialization hierarchy of the classes and supports the inheritance of their properties. A typical IS-A path in the vocabulary has a corresponding shorter SUBCLASS path in the OODB schema. In this paper we expose several cases where the SUBCLASS hierarchy fails to fully correspond to the IS-A hierarchy of the vocabulary. In these cases there exist traversal paths in the semantic network for which there are no corresponding traversal paths in the OODB schema. The reason for this failure is the existence of some IS-A relationships between concepts of two classes, which are not connected by a SUBCLASS relationship. This phenomenon weakens the accuracy of our modeling. To rectify the situation we introduce a new OODB semantic relationship IS-A' to represent the existence of IS-A relationships between concepts of a pair of classes which are not connected via a SUBCLASS relationship. The resulting schema contains both SUBCLASS relationships and IS-A' relationships which completely model the IS-A hierarchy of the vocabulary. We define a mixed-class level traversal path to contain either SUBCLASS or IS-A' relationships. Consequently, each traversal path in the semantic network has a corresponding mixed traversal path in the OODB schema. Hence the introduction of the semantic OODB IS-A' relationship improves the modeling of semantic network vocabularies by OODBs. Copyright (C) 2003 John Wiley Sons, Ltd.

关键词： object-oriented databases object-oriented models object-oriented systems knowledge representation database models vocabulary systems object-oriented hierarchical relationships object-oriented semantic relationships

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