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Knowledge and Data Engineering, IEEE Transactions on

Issue 4 • Date Dec 1989

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Displaying Results 1 - 11 of 11
  • On the data model and access method of summary data management

    Page(s): 519 - 529
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    A data model and an access method for summary data management are presented. Summary data, represented as a trinary tuple ⟨statistical function, category, summary⟩, are metaknowledge summarized by a statistical function of a category of individual information typically stored in a conventional database. For instance, ⟨average-income, female engineer with 10 years' experience and master's degree, $45000⟩ is a summary datum. The computational complexity of the derivability problem has been found intractable in general, and the proposed summary data model, enforcing the disjointness constraint, alleviates the intractable problem without loss of information. In order to store, manage, and access summary data, a multidimensional access method called summary data (SD) tree is proposed. By preserving the category hierarchy, the SD tree provides for efficient operations, including summary data search, derivation, insertion, and deletion View full abstract»

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  • Efficient reordering of Prolog programs

    Page(s): 470 - 482
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    Prolog programs are often inefficient: execution corresponds to a depth-first traversal of an AND/OR graph; traversing subgraphs in another order can be less expensive. It is shown how the reordering of clauses within Prolog predicates, and especially of goals within clauses, can prevent unnecessary search. The characterization and detection of restrictions on reordering is discussed. A system of calling modes for Prolog, geared to reordering, is proposed, and ways to infer them automatically are discussed. The information needed for safe reordering is summarized, and which types can be inferred automatically and which must be provided by the user are considered. An improved method for determining a good order for the goals of Prolog clauses is presented and used as the basis for a reordering system View full abstract»

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  • Conceptual transaction modeling

    Page(s): 508 - 518
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    Transaction modeling, which involves capturing the dynamic properties of an organization, is seen as a necessary component in data modeling. A specification language-transaction schema based on the ACM/PCM specification language-is implemented as the transaction modeling tool. The benefit of such a modeling tool is discussed and, in particular, illustrated by its capability to extend the static schema automatically in order to support the intended transactions View full abstract»

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  • Resolving database incompatibility: an approach to performing relational operations over mismatched domains

    Page(s): 485 - 493
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    A solution to the problem of supporting relational database operations despite domain mismatch is presented. Mismatched domains occur when information must be obtained from databases that were developed independently. Domain differences are resolved by mapping conflicting attributes to common domains by means of a mechanism of virtual attributes and then applying a set of extended relational operations to the resulting values. When one-one mappings cannot be established between domains, the values that result from attribute mappings may be partial. A set of extended relational operators that formalize operations over partial values and thus manipulate the incomplete information that results from resolving domain mismatch is defined View full abstract»

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  • Locking performance in a shared nothing parallel database machine

    Page(s): 530 - 543
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    A quantitative performance study of two-phase locking in a parallel database machine using a simulation-based methodology is described. The DBSIM simulation methodology uses models at two levels: a Petri net model at the higher level and a queuing network model at the lower level. The Petri net model captures the characteristics of parallelism and synchronization at the workload level, while the queuing network model captures queuing aspects of the system at the physical resource level. Transactions in a workload are specified using a performance-oriented specification language based on the transaction component graph, a data flow graph with database operators. The transaction specifications are translated into Petri net representations to derive the simulation experiments. The workload is a transaction taken from an order-entry application. A shared-nothing parallel machine architecture is assumed. Results of analysis of a two-phase locking strategy with machine sizes ranging from 4 to 256 processors are presented View full abstract»

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  • A model for adaptable systems for transaction processing

    Page(s): 433 - 449
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    Adaptability is an essential tool for managing escalating software costs and to build high-reliability, high-performance systems. Algorithmic adaptability, which supports techniques for switching between classes of schedulers in distributed transaction systems, is modeled. RAID, an experimental system implemented to support experimentation in adaptability, is discussed. Adaptability features in RAID, including algorithmic adaptability, fault tolerance, and implementation techniques for an adaptable server-based design, are modeled View full abstract»

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  • A hybrid replica control algorithm combining static and dynamic voting

    Page(s): 459 - 469
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    A hybrid scheme that integrates the static voting protocol and dynamic voting with linearly ordered copies is proposed. A stochastic model is used to compare the file availability afforded by the proposed hybrid scheme with the availabilities of voting, dynamic voting, and dynamic voting with linearly ordered copies. The hybrid scheme has the most availability of these four algorithms for all reasonable repair/failure ratios tested View full abstract»

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  • Measuring the effects of data distribution models on performance evaluation of distributed database systems

    Page(s): 494 - 507
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    The effect of simplistic assumptions about the data distribution and replication in a system on performance measures and the computational complexity and accuracy of evaluations of performance measures is investigated. The size of the participating node set of a transaction is chosen as the desired performance measure. A data distribution and replication model is represented by four key parameters. Probabilistic analysis is used to evaluate six of these models. It is concluded that even though some of the data distribution and replication models appear to be simplistic, the results obtained from them are very close to those from complex models. In addition, the gains due to drastically reduced execution times strongly suggest the use of simple models (at least) in the early stages of the design process View full abstract»

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  • Moving selections into linear least fixpoint queries

    Page(s): 424 - 432
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    Efficient least-fixpoint query evaluation is crucial to using logic as the query language for relational databases. The authors present a selection transposition algorithm that allows selections that are conjunctions of the predicates of the form column θ value to be evaluated ahead of the least-fixpoint operator while processing linear recursive queries. It is also shown that the algorithm transposes the strongest possible selection View full abstract»

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  • An adaptive checkpointing scheme for distributed databases with mixed types of transactions

    Page(s): 450 - 458
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    A checkpointing algorithm that is noninterfering with transaction processing is presented. It prevents the well-known domino effect and saves the intermediate results of a long-lived transaction in an adaptive manner, managing effectively both short- and long-lived transactions in the system View full abstract»

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  • TBSAM: an access method for efficient processing of statistical queries

    Page(s): 414 - 423
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    The domain of statistical and scientific databases is targeted here, and the class of aggregate queries which are very often encountered in this domain is considered. Such a query is aimed at retrieving some aggregate characteristics of the raw data. The tree-based statistics access method (TBSAM), which provides support for the efficient processing of aggregate queries, is presented. It is related to the B+-tree and also processes the B+-tree's efficient update properties. Complementing TBSAM is the provision of a grouped update algorithm for minimizing expensive indexed database updates View full abstract»

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Aims & Scope

IEEE Transactions on Knowledge and Data Engineering (TKDE) informs researchers, developers, managers, strategic planners, users, and others interested in state-of-the-art and state-of-the-practice activities in the knowledge and data engineering area.

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Meet Our Editors

Editor-in-Chief
Jian Pei
Simon Fraser University