A prototype persistence system based on the nitrO reflective system demonstrates that computational reflection is a suitable technique for dynamically and transparently adapting any application's persistence attri...
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A prototype persistence system based on the nitrO reflective system demonstrates that computational reflection is a suitable technique for dynamically and transparently adapting any application's persistence attributes, following the separation-of-concerns principle. Because computational reflection offers the runtime customization of language semantics, it lets developers combine programming language and database management systems into a single computational model.
/Geometric modelling is an integral part of most CAD/CAM applications. However, there is not a widespread and integrated use of geometric modelling throughout the product lifecycle. The primary reason for this is the ...
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/Geometric modelling is an integral part of most CAD/CAM applications. However, there is not a widespread and integrated use of geometric modelling throughout the product lifecycle. The primary reason for this is the differences in the modelling requirements of applications that are used at the various stages of the product development cycle. The paper describes a geometric engine, GNOMES, which provides a geometric modelling framework that can be shared by many applications. This is achieved using a unified representation which can model a large class of point sets that includes nonmanifold point sets, nonclosed point sets, and sets with cracks or missing points. Powerful high-level modelling operations (Boolean, topological, and structural operations) which are useful for constructing more complex models or interrogating the geometric models have been implemented. GNOMES also provides various database facilities through the use of a distributed object-oriented database management system. These facilities include support for persistent GNOMES objects, long and short duration transaction management for concurrent access by multiple applications, a general query facility, and a version and configuration management facility which can be used to record the evolution of GNOMES models. The GNOMES architecture is based on object-oriented principles, and it provides clear abstractions in a small set of encapsulated classes. The goal in developing GNOMES is to provide a geometric engine that is reasonably easy to understand and easily extensible, and that can be used as a basic building block of a collaborative engineering environment. The paper describes the GNOMES representation scheme, its object-oriented design, and sample applications which illustrate various GNOMES functionalities.
EPOS* is an instrumentable, kernel software engineering environment (SEE), featuring change-oriented versioning to manage evolving software products or configurations, through file-based workspaces attached to a versi...
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EPOS* is an instrumentable, kernel software engineering environment (SEE), featuring change-oriented versioning to manage evolving software products or configurations, through file-based workspaces attached to a versioned DBMS. Management of the associated software development processes, i.e. to describe, plan, control and execute software activities. Integration of the two areas above. An object-oriented ERA data model, EPOS-OOER, to describe 'passive' software products and 'active' tasks. Work procedures are expressed as task types, which may be customised through simple versioning in project-specific workspaces. The design, implementation and preliminary experience of EPOS process management is the subject of this paper.
Compensation plays an important role in advanced transaction models, cooperative work and workflow systems. A schema designer is typically required to supply for each transaction T another transaction T-1 to semantica...
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Compensation plays an important role in advanced transaction models, cooperative work and workflow systems. A schema designer is typically required to supply for each transaction T another transaction T-1 to semantically undo the effects of T. Little attention has been paid to the verification of the desirable properties of such operations, however. This paper demonstrates the use of a higher-order logic theorem prover for verifying that compensating transactions return a database to its original state. It is shown how an OODB schema is translated to the language of the theorem prover so that proofs can be performed on the compensating transactions. Copyright (C) 2001 John Wiley & Sons, Ltd.
In this paper, a fuzzy object-oriented Data model (FOOD) is defined based on the extension of a Graph-based object model (D. Lucarella and A. Zanzi "A graph-oriented data model," in Database and Expert Syste...
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In this paper, a fuzzy object-oriented Data model (FOOD) is defined based on the extension of a Graph-based object model (D. Lucarella and A. Zanzi "A graph-oriented data model," in Database and Expert Systems Applications, R. Wagner and H. Toma, Eds., Springer-Verlag, Berlin, 1996, pp. 197-206), in order to manage both crisp and imperfect *** These capabilities are requisites of many current applications dealing with data of different nature and with complex interrelationships. The model is based on a visual paradigm which supports both the representation of the data semantics and the direct browsing of the information. In the extended model both the database scheme and instances are represented as directed labeled graphs in which the fuzzy and uncertain information has its own representation. (C) 1999 John Wiley & Sons, Inc.
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 term 'object-oriented database' has been used to refer to different characteristics and mechanisms supported by semantic databases and (behaviorally) object-oriented ones. while this indicates the current ...
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The term 'object-oriented database' has been used to refer to different characteristics and mechanisms supported by semantic databases and (behaviorally) object-oriented ones. while this indicates the current confusion due to the lack of a common model, it also suggests the potential desirability of combining these two kinds of modeling facilities into the same nutshell. This paper summarizes from these two paradigms the features common to both, the features influenced/adopted by each other, and the features which are presented in one paradigm but missing from the other. After a brief analysis and discussion of these features, we conclude this paper by proposing our major theme: a complete object data model should take the union of the facilities offered by these two kinds of models.
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.
In this paper, the partitioning/allocation model and algorithm for mapping object-oriented (OO) applications into the heterogeneous distributed environments are proposed. Our model applies the graph-theoretic approach...
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In this paper, the partitioning/allocation model and algorithm for mapping object-oriented (OO) applications into the heterogeneous distributed environments are proposed. Our model applies the graph-theoretic approach, dealing with a lot of characteristics of OO paradigm. In addition, individual metrics for communication cost, concurrency and load balance are defined. Our allocation algorithm is based on the Niched Pareto Genetic Algorithm (NPGA). The reason for using this technique is that a partitioning/allocation problem is multiobjective problem with non-commensurable (measured in different unit) objectives, and NPGA was proved to be effective in this kind of problem. We validated our model and algorithm by experimenting on the three typical OO systems in CORBA-based distributed environments. The main advantage of this approach is that the algorithm produces not a single solution, but a family of solutions known as the Pareto-optimal set, out of which the developer can select an optimal solution appropriate for his or her environmental conditions.
In this work, we deal with temporal abstraction of clinical data. Abstractions are, for example, blood pressure state (e.g. normal, high, low) and trend (e.g. increasing, decreasing and stationary) over time intervals...
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In this work, we deal with temporal abstraction of clinical data. Abstractions are, for example, blood pressure state (e.g. normal, high, low) and trend (e.g. increasing, decreasing and stationary) over time intervals. The goal of our work is to provide clinicians with automatic tools to extract high-level, concise, important features of available collections of time-stamped clinical data. This capability is especially important when the available collections constantly increase in size, as in long-term clinical follow-up, leading to information overload. The approach we propose exploits the integration of the deductive and object-oriented approaches in clinical databases. The main result of this work is an object-oriented data model based on the event calculus to support temporal abstraction. The proposed approach has been validated building the CARDIOTABS system for the abstraction of clinical data collected during echocardiographic tests. (C) 1999 Elsevier Science B.V. All rights reserved.
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