We present results of providing database support to biomedicine via federation of SDB Cooperation/Integration based upon the KEGG GUI for molecular biology. The federation provides a common link to three molecular bio...
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We present results of providing database support to biomedicine via federation of SDB Cooperation/Integration based upon the KEGG GUI for molecular biology. The federation provides a common link to three molecular biology databases. The added value of the federation is freedom from consulting multiple references to ascertain the full set of enzymatic reactions in a metabolic pathway, and the option of selecting multiple queries to submit to the federated SDBs. Each of the SDBs is extensive, but incomplete. The union of the SDBs, implemented transparently by the federation, is more complete. Each SDB provides a different approach to the options available for data presentation and a different set of Web server tools for data analysis. Thus, an important part of the added value of the federation is the cross-fertilization available in the union of the molecular biological content, the presentation of data, and the tools available for analysis.
A distributed computing system consists of heterogeneous computing devices, communication networks, operating system services, and applications. As organisations move toward distributed computing environments, there w...
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A distributed computing system consists of heterogeneous computing devices, communication networks, operating system services, and applications. As organisations move toward distributed computing environments, there will be a corresponding growth in distributed applications central to the enterprise. The design, development, and management of distributed applications presents many difficult challenges. As these systems grow to hundreds or even thousands of devices and similar or greater magnitude of software components, it will become increasingly difficult to manage them without appropriate support tools and frameworks. Further, the design and deployment of additional applications and services will be, at best, ad hoc without modelling tools and timely data on which to base design and configuration decisions. This paper presents a framework for management of distributed applications and systems. The framework is based on a set of common management services that support management activities. The services include monitoring, control, configuration, and data repository services. A prototype system built on the framework is described that implements and integrates management applications providing visualisation, fault location, performance monitoring and modelling, and configuration management. The prototype also demonstrates how various management services can be implemented.
This paper targets engineers and practitioners who want a simple procedure to compute the mean performance measures of the Batch Markovian Arrival process (BMAP/G/1) queueing system when the parameter matrices order i...
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View materialization is known to be a valuable technique for performance optimization in relational databases, and much work has been done addressing the problem of consistently maintaining relational views under upda...
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View materialization is known to be a valuable technique for performance optimization in relational databases, and much work has been done addressing the problem of consistently maintaining relational views under update operations. However, little progress has been made thus far regarding the topic of view materialization in object-oriented databases (OODBs). In this paper, we demonstrate that there are several significant differences between the relational and object-oriented paradigms that can be exploited when addressing the object-oriented view materialization problem. We use the subsumption relationships between classes to identify branches of classes to which we do not need to propagate updates. Similarly, we use encapsulated interfaces combined with the fact that any unique database property is inherited from a single location to provide a "registration/notification" service for optimizing incremental view updates. We also report results from the experimental studies we have run on the MultiView system measuring the impact of these optimization strategies.
Materialized complex object-oriented views are a promising technique for the integration of heterogeneous databases and the development of powerful data warehousing systems. Path query views are virtual classes formed...
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Materialized complex object-oriented views are a promising technique for the integration of heterogeneous databases and the development of powerful data warehousing systems. Path query views are virtual classes formed from selection queries that specify a predicate upon the value of an aggregation hierarchy path. The primary difference between previous work regarding OODB indexing and the efficient implementation of materialized path query views addressed in this paper lies in the nature of their usage. For OODB indexing, query usage is the primary purpose of index structures. Because the materialized view data itself can be used to answer queries, the primary use of index structures with regard to materialized path query views is for the incremental maintenance of views in the face of updates. We have developed an augmented inherited multi-index (AIM) strategy that is specifically tailored for the maintenance of materialized path query views. We find that we can improve update performance by augmenting traditional inherited multi-indices with structured representations of the path queries that use them. This enables us to use class hierarchy relationships to prune the number of aggregation paths that must be re-instantiated during update propagation and also to support complex path queries that include cycles.
We have developed the transparent schema evolution (TSE) system that, simulating schema evolution using object-oriented views, allows for the interoperability of applications with diverse and even changing requirement...
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We have developed the transparent schema evolution (TSE) system that, simulating schema evolution using object-oriented views, allows for the interoperability of applications with diverse and even changing requirements. TSE relieves users of the risk of making existing application programs obsolete when run against the modified schema, because the old view schema is maintained while a new view schema is generated to capture the changes desired by the user. However TSE may be generating a large number of schema versions (object-oriented view schemata) over time, resulting in an excessive build-up of classes and underlying object instances-some of which may potentially no longer be in use. We propose to solve this problem by developing techniques for effective and consistent schema removal. First, we characterize four potential problems of schema consistency that could be caused by removal of a single virtual class; and then outline our solution approach for each of these problems. Second, we demonstrate that view schema removal is sensitive to the order in which individual classes are processed. Our solution to this problem is the development of a dependency graph model for capturing the class relationships, used as a foundation for selecting among removal sequences. Designed to optimize the performance of the TSE system by effective schema version removal, the proposed techniques will enable more effective interoperability among evolving software applications.
It is a generally accepted concept that multiple views are needed in object-oriented analysis or domain analysis techniques. Three commonly adopted models for requirements analysis include object model, functional mod...
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It is a generally accepted concept that multiple views are needed in object-oriented analysis or domain analysis techniques. Three commonly adopted models for requirements analysis include object model, functional model and dynamic model. This paper introduces and incorporates the concept of relational modeling into the analysis techniques. Relational modeling mainly deals with two tasks: classification of semantic relations and identification of higher-order system causal relations. Classification of semantic relations supports comparison and evaluation of various relations, which in turn can be used to select suitable methods to process the relations. A higher-order relation depicts the relations between different relations as opposed to the relations between objects often discussed in object modeling. A network of higher-order relations reveals the cause-effect dependency relationships and can facilitate understanding and reasoning of application systems. Furthermore, incorporation of relational modeling techniques can support software reuse in an application domain or across domains.
Scientific applications often require some strategy for temporary data storage to do the largest possible simulations. The use of virtual memory for temporary data storage has received criticism because of performance...
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ISBN:
(纸本)9780897918541
Scientific applications often require some strategy for temporary data storage to do the largest possible simulations. The use of virtual memory for temporary data storage has received criticism because of performance problems. However, modern virtual memory found in recent operating systems such as Cenju-3/DE give application writers control over virtual memory policies. We demonstrate that custom virtual memory policies can dramatically reduce virtual memory overhead and allow applications to run out-of-core efficiently. We also demonstrate that the main advantage of virtual memory, namely programming simplicity, is not lost.
Scientific applications often require some strategy for temporary data storage to do the largest possible simulations. The use of virtual memory for temporary data storage has received criticism because of performance...
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Scientific applications often require some strategy for temporary data storage to do the largest possible simulations. The use of virtual memory for temporary data storage has received criticism because of performance problems. However, modern virtual memory found in recent operating systems such as Cenju-3/DE give application writers control over virtual memory policies. We demonstrate that custom virtual memory policies can dramatically reduce virtual memory overhead and allow applications to run out-of-core efficiently. We also demonstrate that the main advantage of virtual memory, namely programming simplicity, is not lost.
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