This paper describes a testbed architecture for the investigation and development of scalable approaches to the management and analysis of massive amounts of high energy physics data. The architecture has two componen...
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This paper describes a testbed architecture for the investigation and development of scalable approaches to the management and analysis of massive amounts of high energy physics data. The architecture has two components: an interface layer that is compliant with a substantial subset of the ODMG-93 Version 1.2 specification, and a lightweight object persistence manager that provides flexible storage and retrieval services on a variety of single- and multi-level storage architectures, and on a range of parallel and distributed computing platforms. Published by Elsevier Science B.V.
This paper presents a methodology for handling an important step of database migration. The methodology is based on a set of techniques: (i) semantic clustering, (ii) metamodeling, and (iii) knowledge-based schema tra...
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This paper presents a methodology for handling an important step of database migration. The methodology is based on a set of techniques: (i) semantic clustering, (ii) metamodeling, and (iii) knowledge-based schema transformation. Semantic clustering (i.e., grouping based on semantic cohesion) is mainly used to facilitate the process of translating an extended entity relationship schema into a schema of complex objects. Meta modeling is used to define the data models involved in the process of schema transformation. Finally, transformation rules are defined and used for mapping a schema from a source model into a schema expressed in a target model. In this paper, we limit ourselves to the mapping of an extended entity relationship diagram into an object-oriented database schema using the object model supported by the ODMG standard. (C) 1998 Elsevier Science B.V.
The efficient execution of queries in object-oriented databases requires the design of specific indexing techniques, to efficiently deal with predicates against nested attributes or against class inheritance hierarchi...
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The efficient execution of queries in object-oriented databases requires the design of specific indexing techniques, to efficiently deal with predicates against nested attributes or against class inheritance hierarchies. Indexing techniques so far proposed can be classified into three groups: inheritance indexing techniques, whose goal is to support queries along inheritance hierarchies;aggregation indexing techniques, dealing with the efficient evaluation of nested predicates;integrated techniques. The aim of this paper is to analyze two techniques providing an integrated support, the path index and the nested-inherited index, with respect to traditional techniques, such as the multi-index and the inherited multi-index. The analysis is performed assuming that multi-valued attributes, as well as instances with null attribute values, are present in the database. For this purpose, the paper first presents the considered techniques. An extension of the path index, firstly defined in [6], is proposed to deal with multi-valued attributes and instances with null attribute values. Then, an analytical cost model for the extended version of the path index is presented. The cost model is finally used, together with the cost models presented in [2], to compare the various index costs, with respect to storage, retrieval, delete and insert operations. The results show that traditional techniques have better performance with respect to storage, delete and insert costs, whereas integrated techniques have lowest costs for retrieval. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
Many object-oriented database systems have used the notion of implicit authorization to avoid the overhead caused by explicitly storing all authorizations for each object. In implicit authorization, it is very importa...
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Many object-oriented database systems have used the notion of implicit authorization to avoid the overhead caused by explicitly storing all authorizations for each object. In implicit authorization, it is very important to detect efficiently conflicts between existing authorizations and new authorizations to be added. In this article we propose a conflict detection mechanism in the OODBMSs using implicit authorization with the notion of intention type authorization. When Lye grant an authorization on a node n in the database granularity hierarchy, the existing method is inefficient in determining the conflicts since it needs to examine all authorizations on the descendants of the node n. In contrast, our mechanism has the advantage of detecting the conflicts at the node n where an explicit authorization is to be granted without examining any authorizations below the node n. Thus, the proposed mechanism can detect a conflict with the average time complexity of O(d), which is smaller than O(m(d)) of existing methods, where m is the number of children nodes at an arbitrary level and d is the difference of levels between the node with an existing explicit authorization and the higher node where an explicit authorization is to be granted. We also show that the additional storage overhead of storing all authorizations is negligible when compared with the total number of all explicit authorizations.
Internet programming languages such as Java present new challenges to garbage-collection design. The spectrum of garbage-collection sehema for linked structures distributed over a network are reviewed here. Distribute...
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Internet programming languages such as Java present new challenges to garbage-collection design. The spectrum of garbage-collection sehema for linked structures distributed over a network are reviewed here. Distributed garbage collectors are classified first because they evolved from single-address-space collectors, This taxonomy is used as a framework to explore distribution issues: locality of action, communication overhead and indeterministic communication latency.
The evolution of object-oriented databases (OODBs) has not been accompanied by an equivalent evolution of theoretical models, leaving the foundations for OODBs ill-defined. Design of OODBs has been hampered by the lac...
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The evolution of object-oriented databases (OODBs) has not been accompanied by an equivalent evolution of theoretical models, leaving the foundations for OODBs ill-defined. Design of OODBs has been hampered by the lack of design techniques/tools which correspond to the theoretical model. This paper defines a core conceptual object-oriented database (COODB) model providing a foundation and framework for theoretical research. Structural and behavioral definitions for an object, a class, and a class hierarchy are given. A specification hierarchy is introduced as a design tool, and a messaging component is defined which enables asynchronous and synchronous interaction. (C) 1998 Elsevier Science Inc. All rights reserved.
ADOME, which stands for ADvanced object Modeling Environment is an approach to integrating data and knowledge management based on object-oriented technology. Next generation information systems will require more flexi...
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ADOME, which stands for ADvanced object Modeling Environment is an approach to integrating data and knowledge management based on object-oriented technology. Next generation information systems will require more flexible data modeling capabilities than those provided by current object-oriented DBMSs. In particular, integration of data and knowledge management capabilities will become increasingly important. In this context, ADOME provides versatile role facilities that serve as "dynamic binders" between data objects and production rules, thereby facilitating flexible data and knowledge management integration. A prototype that implements this mechanism and the associated operators has been constructed on top of a commercial object-oriented DBMS and a rule-base system.
A path-method is used as a mechanism in object-oriented databases (OODBs) to retrieve or to update information relevant to one class that is not stored with that class but with some other class. A path-method is a met...
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A path-method is used as a mechanism in object-oriented databases (OODBs) to retrieve or to update information relevant to one class that is not stored with that class but with some other class. A path-method is a method which traverses from one class through a chain of connections between classes and accesses information at another class. However, it is a difficult task for a casual user or even an application programmer to write path-methods to facilitate queries. This is because it might require comprehensive knowledge of many classes of the conceptual schema that are not directly involved in the query, and therefore may not even be included in a user's (incomplete) view about the contents of the database. We have developed a system, called path-method generator (PMG), which generates path-methods automatically according to a user's database-manipulating requests. The PMG offers the user one of the possible path-methods and the user verifies from his knowledge of the intended purpose of the request whether that path-method is the desired one. If the path method is rejected, then the user can utilize his now increased knowledge about the database to request (with additional parameters given) another offer from the PMG. The PMG is based on access weights attached to the connections between classes and precomputed access relevance between every pair of classes of the OODB. Specific rules for access weight assignment and algorithms for computing access relevance appeared in our previous papers [MGPF92, MGPF93, MGPF96]. In this paper, we present a variety of traversal algorithms based on access weights and precomputed access relevance. Experiments identify some of these algorithms as very successful in generating most desired path-methods. The PMG system utilizes these successful algorithms and is thus an efficient tool for aiding the user with the difficult task of querying and updating a large OODB.
A new method for viewing and manipulating identity-based object structures is proposed. The method is founded on the viewing the object structure as an object graph which in turn is represented as a set of paths. Over...
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A new method for viewing and manipulating identity-based object structures is proposed. The method is founded on the viewing the object structure as an object graph which in turn is represented as a set of paths. Over a power set of paths we construct a powerdomain which forms a lattice with well-defined meet and join operations. In our construction of the powerdomain of paths we combine the Hoare ordering (appropriate for ordering of tuple objects) with the Smyth ordering (appropriate for ordering of set objects) into a new ordering appropriate for set of paths capturing information conveyed by both tuple and set objects. The approach allows to deal with incomplete tuple objects as well as with partially described sets. The goal of the powerdomain construction is to provide a semantic domain for a path calculus language [20], where path calculus variables range over paths and path calculus queries give sets of paths as their answers.
This paper describes an environment for constructing multimedia applications which are used to present different multimedia database objects in accordance with spatiotemporal constraints and from different sources. Th...
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ISBN:
(纸本)0818672250
This paper describes an environment for constructing multimedia applications which are used to present different multimedia database objects in accordance with spatiotemporal constraints and from different sources. The main contribution of this paper is to propose an environment which integrates both a modelling case tool and an object-oriented database system.
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