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Knowledge and Data Engineering, IEEE Transactions on

Issue 2 • Date Jun 1989

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Displaying Results 1 - 10 of 10
  • Algorithms for distributed query processing in broadcast local area networks

    Page(s): 215 - 225
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB)  

    Distributed query-processing algorithms for broadcast local-area networks are described which provide execution strategies and estimates of response time. Four semijoin-specific techniques, five transmission-specific techniques, and three size estimation update functions are incorporated into a baseline algorithm. These variants of the baseline algorithm are simulated and their response times compared using randomly generated data. The technique found to be most beneficial, on the average, for general queries involving multiple joining attributes is the composite semijoining technique. When used in combination with composite semijoining, relation transmission and bit-matrix transmission further reduce response time. Bit-matrix transmission is a data compression technique in which single attributes and a bit matrix of the value pairings are sent in place of a composite attribute. The authors examine these techniques in detail and compare their expected response times View full abstract»

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  • An intelligent search method for query optimization by semijoins

    Page(s): 226 - 237
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1076 KB)  

    The problem of finding an optimal semijoin sequence that fully reduces a given tree query is discussed. A method is presented that intelligently navigates the space of all semijoin sequences and returns an optimal solution. Experiments are reported that show that this method performs very efficiently: on average, less than 5% of the search space is searched before an optimal solution is found. Other advantages of the method are ease of implementation, generality of the cost mode considered, and ability to handle tree queries with arbitrary target lists View full abstract»

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  • Selection of indexes to memory-resident entities for semantic data models

    Page(s): 274 - 284
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    A variation of the index selection problem for an extended relational model when all encoding of information is memory resident is discussed. The data model is the relational model extended in two ways that are common with semantic data models. One consequence of memory residence is that the search space of possible indexes is enlarged to the extent that previous methods requiring some consideration of each possibility are no longer possible. An instance of the index selection problem that includes a set of partial match queries in addition to the input schema is given. It is assumed that the set is determined by an initial phase of query optimization when applied to a fixed set of more general forms of queries that characterize the way in which information is accessed for an application. An initial choice of indexes is made, only considering their suitability for answering the partial match queries View full abstract»

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  • An efficient file structure for document retrieval in the automated office environment

    Page(s): 258 - 273
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1612 KB)  

    A file system tailored to the general needs of the office environment is proposed. This system supports large numbers of a wide variety of documents and inexact fuzzy queries on the documents. The file system is based on a multilevel file structure that combines and extends multikey extendible hashing and signature files to create a document-retrieval system that is more time efficient than other previously proposed systems and is also space efficient View full abstract»

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  • Directory reference patterns in hierarchical file systems

    Page(s): 238 - 247
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    The authors present a brief description of data on directory reference patterns collected from a 4.2BSD UNIX system. These data are used to examine the importance of the name lookup overhead involved in opening and using files. The analysis shows that paths in the environment are relatively long and that, in the absence of caching, name resolution overhead accounts for over 70% of the disk blocks referenced to open and use files. These results confirm recent conjectures on the high level of directory activity in UNIX file systems. Directory references exhibit strong locality, though, making caches an effective way to decrease directory overhead. Simulations of a least recently used (IRU) whole directory cache show that a cache holding just ten nodes achieves an 85% hit ratio. The implications of these results on the design of both local and distributed file systems are discussed View full abstract»

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  • The ROSE data manager: using object technology to support interactive engineering applications

    Page(s): 285 - 289
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    The relational object system for engineering (ROSE) is an experimental database system for interactive engineering applications. The ROSE system and the way it uses object technology are described. The system has an open architecture which allows new tools to be added easily. Several tools are described, including an inheritance manager, version control system, and user interface manager. These tools enhance the ROSE system and broaden its application to other types of data-management problems View full abstract»

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  • Asynchronous chain recursions

    Page(s): 185 - 195
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    The authors study the compilation and efficient processing of asynchronous chain recursions and show that many complex function-free recursions, which may contain single or multiple linear recursive rules, nonlinear recursive rules, mutually recursive rules, and multiple-level recursions, can be compiled to asynchronous chain recursions. The study on the compilation methods, the simplification of compiled formulas, and the query-processing techniques shows that asynchronous chain recursions can be compiled to relatively simple compiled formulas and processed efficiently using transitive closure query-processing methods View full abstract»

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  • Performance of B+-trees with partial expansions

    Page(s): 248 - 257
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    The authors mathematically analyze the behavior of B+-trees with partial expansions file structure under random insertions, focusing on the expected storage utilization and the expected cost of insertions. The model can be used for studying both the asymptotic and dynamic behavior. The accuracy of the model is confirmed by simulation. Disk space management is found to be more difficult than for standard B+-trees. Two simple space-management schemes specifically designed for handling buckets of two different sizes are investigated. It is found that an overall storage utilization of 81% can be achieved in practice View full abstract»

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  • Indexing techniques for queries on nested objects

    Page(s): 196 - 214
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    Three index organizations are introduced for use in the evaluation of a query in an object-oriented or nested relational database. Detailed models of the three indexes are developed. Using the models, the storage cost, retrieval cost, and update cost of these indexes are evaluated, and a number of observations are made about the use of these indexes for evaluating queries for object-oriented or nested relational databases. A comparison of the combined retrieval and update costs for the three indexes is also included. It is shown that the degree of reference sharing among objects for the various classes in the path influences both the retrieval and update costs View full abstract»

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  • Updating distributed materialized views

    Page(s): 173 - 184
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    The problem of updating materialized views in distributed database systems is discussed. An architecture and detailed procedures for updating a collection of remote views with arbitrary refresh times by using a single differential file are described. The efficiency of the update procedure is enhanced by adopting s multiquery optimization approach and by introducing a powerful prescreening procedure to eliminate differential tuples. It is shown that even for a single remote view, there are many instances where the update procedure performs better (with respect to total I/O and communication costs) than a base table approach 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