By Topic

Data Engineering, 1996. Proceedings of the Twelfth International Conference on

Date Feb. 26 1996-March 1 1996

Filter Results

Displaying Results 1 - 25 of 80
  • IN MEMORIAM James Clifford

    Publication Year: 1996
    Save to Project icon | Request Permissions | PDF file iconPDF (33 KB)  
    Freely Available from IEEE
  • IN MEMORIAM Gennady Antoshenkov

    Publication Year: 1996
    Save to Project icon | Request Permissions | PDF file iconPDF (73 KB)  
    Freely Available from IEEE
  • Author index

    Publication Year: 1996
    Save to Project icon | Request Permissions | PDF file iconPDF (149 KB)  
    Freely Available from IEEE
  • A next-generation industry multimedia database system

    Publication Year: 1996 , Page(s): 364 - 371
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    New multimedia applications have emerged on top of information infrastructures, such as on-demand services, digital libraries and museums, online shopping and document management, which require new databases. That is, next-generation database systems must enable users to efficiently and flexibly develop and execute such advanced multimedia applications. We focus on development of a database system which enables flexible and efficient acquisition, storage, access and retrieval, and distribution and presentation of large amounts of heterogeneous media data. We take an approach based on an object-oriented database, which is more suitable for the description of media structures and operations than a traditional relational database. We extend the object-oriented approach by providing temporal and spatial operators, and control of distributing computing and QOS (quality of service). In this paper, we describe a multimedia data model and its efficient implementation View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evaluation and optimization of the LIVING IN A LATTICE rule language

    Publication Year: 1996 , Page(s): 318 - 325
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB)  

    We introduce an evaluation technique for a declarative object-oriented database (OODB) query language. The query language is rule-based and can be evaluated and optimized using an appropriate object algebra. We introduce a new framework which uses concepts of the object-oriented data model to define adequate accesses to the database. Additionally, problems according to the evaluation of recursive queries are discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A log-stuctured organization for tertiary storage

    Publication Year: 1996 , Page(s): 20 - 27
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB)  

    We present the design of a log-structured tertiary storage (LTS) system. The advantage of this approach is that it allows the system to hide the details of jukebox robotics and media characteristics behind a uniform, random-access, block-oriented interface. It also allows the system to avoid media mount operations for writes, giving a write performance similar to that of secondary storage View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Microsoft relational engine

    Publication Year: 1996 , Page(s): 160 - 161
    Cited by:  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    Microsoft offers three very successful database products, FoxPro, Access and SQL Server. While SQL Server excels in multi-user transaction performance, Access and its underlying Jet engine excel as an end-user and development tool for desktop and client-server applications. One of our top priorities is to improve the integration of these two products. With respect to their query processing capabilities, we plan on combining the strengths of SQL Server with those of Access. SQL Server's strengths are focused on management of very large tables, server-side cursors, and the use of stored procedures as scripts and as triggers. Access strengths are queries over multiple servers, updatable query results, and bit-mapped processing. In our next generation of products, SQL Server will employ new query processing technology. Both optimization and execution will be based on an extensible set of operators. We are focusing on the relational algebra augmented with a few operators such as the top operator found in Access, and suitable loops-, index-, sort-, hash-, and bitmap-based execution algorithms. Moreover, we are planning on executing these algorithms both sequentially and in parallel. We have four design goals, namely functionality, performance, scalability, and extensibility View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Speculative data dissemination and service to reduce server load, network traffic and service time in distributed information systems

    Publication Year: 1996 , Page(s): 180 - 187
    Cited by:  Papers (27)  |  Patents (46)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB)  

    We present two server-initiated protocols to improve the performance of distributed information systems (e.g. WWW). Our first protocol is a hierarchical data dissemination mechanism that allows information to propagate from its producers to servers that are closer to its consumers. This dissemination reduces network traffic and balances load amongst servers by exploiting geographic and temporal locality of reference properties exhibited in client access patterns. Our second protocol relies on “speculative service”, whereby a request for a document as serviced by sending, in addition to the document requested, a number of other documents that the server speculates will be requested in the near future. This speculation reduces service time by exploiting the spatial locality of reference property. We present results of trace-driven simulations that quantify the attainable performance gains for both protocols View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Knowledge discovery from telecommunication network alarm databases

    Publication Year: 1996 , Page(s): 115 - 122
    Cited by:  Papers (19)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    A telecommunication network produces daily large amounts of alarm data. The data contains hidden valuable knowledge about the behavior of the network. This knowledge can be used in filtering redundant alarms, locating problems in, the network, and possibly in predicting severe faults. We describe the TASA (Telecommunication Network Alarm Sequence Analyzer) system for discovering and browsing knowledge from large alarm databases. The system is built on the basis of viewing knowledge discovery as an interactive and iterative process, containing data collection, pattern discovery, rule postprocessing, etc. The system uses a novel framework for locating frequently occurring episodes from sequential data. The TASA system offers a variety of selection and ordering criteria for episodes, and supports iterative retrieval from the discovered knowledge. This means that a large part of the iterative nature of the KDD process can be replaced by iteration in the rule postprocessing stage. The user interface is based on dynamically generated HTML. The system is in experimental use, and the results are encouraging: some of the discovered knowledge is being integrated into the alarm handling software of telecommunication operators View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Approximate queries and representations for large data sequences

    Publication Year: 1996 , Page(s): 536 - 545
    Cited by:  Papers (29)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (892 KB)  

    Many new database application domains such as experimental sciences and medicine are characterized by large sequences as their main form of data. Using approximate representation can significantly reduce the required storage and search space. A good choice of representation, can support a broad new class of approximate queries, needed in there domains. These queries are concerned with application dependent features of the data as opposed to the actual sampled points. We introduce a new notion of generalized approximate queries and a general divide and conquer approach that supports them. This approach uses families of real-valued functions as an approximate representation. We present an algorithm for realizing our technique, and the results of applying it to medical cardiology data View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Prefetching from a broadcast disk

    Publication Year: 1996 , Page(s): 276 - 285
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1036 KB)  

    Broadcast disks have been proposed as a means to efficiently deliver data to clients in “asymmetric” environments where the available bandwidth from the server to the clients greatly exceeds the bandwidth in the opposite direction. A previous study investigated the use of cost based caching to improve performance when clients access the broadcast in a demand driven manner (S. Acharya et al., 1995). Such demand driven access however, does not fully exploit the dissemination based nature of the broadcast, which is particularly conducive to client prefetching. With a broadcast disk, pages continually flow past the clients so that in contrast to traditional environments, prefetching can be performed without placing additional load on shared resources. We argue for the use of a simple prefetch heuristic called PT and show that PT balances the cache residency time of a data item with its bandwidth allocation. Because of this tradeoff, PT is very tolerant of variations in the broadcast program. We describe an implementable approximation for PT and examine its sensitivity to access probability estimation errors. The results show that the technique is effective even when the probability estimation is substantially different from the actual values View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Synthesizing distributed constrained events from transactional workflow specifications

    Publication Year: 1996 , Page(s): 616 - 623
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    Workflows are the semantically appropriate composite activities in heterogeneous computing environments. Such environments typically comprise a great diversity of locally autonomous databases, applications and interfaces. Much good research has focused on the semantics of workflows and how to capture them in different extended transaction models. We address the complementary issues pertaining to how workflows may be declaratively specified and how distributed constraints may be derived from those specifications to enable local control, thus obviating a centralized scheduler. Previous approaches to this problem were limited and often lacked a formal semantics View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • DB2 LOBs: the teenage years

    Publication Year: 1996 , Page(s): 192 - 199
    Cited by:  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (740 KB)  

    Previous versions of DB2 Common Server had large objects (LOBs) that were neither large nor functional. Their size was limited to 32,700 bytes and, until recently when support for SUBSTR and CONCAT was added, there was no function available on these objects at all. DB2 LOBs were infants. However, with the latest release of DB2 Common Server, Version 2.1, LOBs have matured considerably supporting significantly larger sizes and many new language features. To give the reader a feeling for the extent of this new language support, we compare our new SQL LOB language features with that of three other major relational database competitors: Sybase, Informix and Oracle. Users will find the new DB2 LOBS easy to load and store, easy to search, and easy to integrate into the DB2 user-defined functions (UDFs) and user-defined types (UDTs). In addition, when used in serial mode, the performance of LOB I/O rivals that of file systems and, when used in parallel mode, is a clear winner. DB2 LOBs have now entered the teenage years View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Workflow and data management in InConcert

    Publication Year: 1996 , Page(s): 497 - 499
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    InConcert is an object-oriented client-server workflow management system. An overview is provided of the functionality of InConcert and how it is implemented on an underlying relational database management system. Data management issues in supporting distributed workflow are briefly reviewed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An executable graphical representation of mediatory information systems

    Publication Year: 1996 , Page(s): 124 - 131
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    We present an approach towards a unified modeling and query processing tool for mediatory information systems. Based upon coloured Petri nets we are able to model the integration of parametric data (external, uncertain and temporal information) and to visualize the dataflow in mediatory information systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A transactional nested process management system

    Publication Year: 1996 , Page(s): 566 - 573
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    Providing flexible transaction semantics and incorporating activities, data and agents are the key issues in workflow system development. Unfortunately, most of the commercial workflow systems lack the advanced features of transaction models, and an individual transaction model with specific emphasis lacks sufficient coverage for business process management. This report presents our solutions to the above problems in developing the Open Process Management System (OPMS) at HP Laboratories. OPMS is based on nested activity modeling with the following extensions and constraints: `in-process open nesting' for extending closed/open nesting to accommodate applications that require improved process-wide concurrency without sacrificing top-level atomicity; `confined open' as a constraint on both open and in-process open activities for avoiding the semantic inconsistencies in activity triggering and compensation; and `two-phase remedy' as a generalized hierarchical approach for handling failures View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • ActionWorkflow in use: Clark County Department of Business License

    Publication Year: 1996 , Page(s): 288 - 294
    Cited by:  Papers (1)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    We present the basic concepts of ActionWorkflow and a study of a successful implementation in Clark County Department of Business License. The image/workflow system reengineers a labyrinthine licensing system into simplistic processes that are more customer oriented, yield superior productivity, establish a work in progress tracking mechanism, and archive the resulting licensing processes permanently on an unalterable optical storage system View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reusing (shrink wrap) schemas by modifying concept schemas

    Publication Year: 1996 , Page(s): 326 - 333
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    A shrink-wrap schema is a well-crafted, complete, global schema that represents an application. A concept schema is a subset of the shrink-wrap schema that addresses one particular point of view in an application. We define schema modification operations to customize each concept schema, to match the designer's perception of the application. We maintain the integrated, customized user schema. We enforce consistency checks to provide feedback to the designer about interactions among the concept schemas. We embody these mechanisms in an interactive system that aids in shrink-wrap schema-based design. The shrink-wrap schema approach promotes reuse of past design efforts; prior approaches to schema reuse did not attempt to reuse an entire schema nor did they focus on local customization. The focus of this paper is on the definition of concept schemas and their corresponding modification operations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An SQL3 snapshot

    Publication Year: 1996 , Page(s): 666 - 672
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    The third major generation of the standard for the SQL database language, known as SQL3, is nearing completion. Many significant new features have been added to SQL, both in areas traditionally addressed by SQL and in pursuit of adding object technology to the language. The standard has been partitioned into a number of distinct parts, each of which may progress at its own rate. Publication of SQL3 as a replacement for the current version of the standard, SQL-92, is expected no sooner than 1998 View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Deferred updates and data placement in distributed databases

    Publication Year: 1996 , Page(s): 469 - 476
    Cited by:  Papers (8)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    Commercial distributed database systems generally support an optional protocol that provides loose consistency of replicas, allowing replicas to be inconsistent for some time. In such a protocol, each replicated data item is assigned a primary copy site. Typically, a transaction updates only the primary copies of data items, with updates to other copies deferred until after the transaction commits. After a transaction commits, its updates to primary copies are sent transactionally to the other sites containing secondary copies. We investigate the transaction model underlying the above protocol. We show that global serializability in such a system is a property of the placement of primary and secondary copies of replicated data items. We present a polynomial time algorithm to assign primary sites to data items so that the resulting topology ensures serializability View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • VISUAL: a graphical icon-based query language

    Publication Year: 1996 , Page(s): 524 - 533
    Cited by:  Papers (7)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (964 KB)  

    VISUAL is a graphical icon-based query language designed for scientific databases where visualization of the relationships are important for the domain scientist to express queries. Graphical objects are not tied to the underlying formalism; instead, they represent the relationships of the application domain. VISUAL supports relational, nested, and object-oriented models naturally and has formal basis. In addition to set and bag constructs for complex objects, sequences are also supported by the data model. Concepts of external and internal queries are developed as modularization tools. A new parallel/distributed query processing paradigm is presented. VISUAL query processing techniques are also discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transaction management for a distributed object storage system WAKASHI-design, implementation and performance

    Publication Year: 1996 , Page(s): 460 - 468
    Cited by:  Papers (10)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1000 KB)  

    This paper presents the transaction management in a high performance distributed object storage system WAKASHI. Unlike other systems that use centralized client/server architecture and other conventional buffer management for distributed persistent object management, WAKASHI is based on symmetric peer-peer architecture and employs memory-mapping and distributed shared virtual memory techniques. Several novel techniques of transaction management for WAKASHI are developed. First, a multi-threaded transaction manager offers “multi-threaded connection” so that data control and transaction operations can be performed in parallel manner. Secondly, a concurrency control mechanism supports transparent page-level locks to reduce the complexity of user programs and locking overhead. Thirdly, a “compact commit” method is proposed to minimize the communication cost by reducing the amount of data and the number of connections. Fourthly, a redo-only recovery method is implemented by “shadowed cache” method to minimize the logging cost, and to allow fast recovery and system restart. Moreover, the system offers “hierarchical” control to support nested transactions. A performance evaluation by the OO7 benchmark is presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Query answering using discovered rules

    Publication Year: 1996 , Page(s): 402 - 411
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (824 KB)  

    Research has been done in discovering rules from databases and in applying these rules to intensional answers to database queries, semantic query optimization, etc. However, rules discovered by one group of users may not be used by other groups of users in their applications due to certain mismatches. In this paper, we address the problems of using discovered rules for query answering, and then propose algorithms for rewriting, applying and maintaining these rules View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Towards eliminating random I/O in hash joins

    Publication Year: 1996 , Page(s): 422 - 429
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    The widening performance gap between CPUs and disks is significant for hash join performance. Most current hash join methods try to reduce the volume of data transferred between memory and disk. In this paper, we try to reduce hash-join times by reducing random I/O. We study how current algorithms incur random I/O, and propose a new hash join method, Seq+, that converts much of the random I/O to sequential I/O. Seq+ uses a new organization for hash buckets on a disk, and larger input and output buffer sizes. We introduce the technique of batch writes to reduce the bucket-write cost, and the concepts of write- and read-groups of hash buckets to reduce the bucket-read cost. We derive a cost model for our method and present formulas for choosing various algorithm parameters, including input and output buffer sizes. Our performance study shows that the new hash join method performs many times better than current algorithms under various environments. Since our cost functions underestimate the cost of current algorithms and overestimate the cost of Seq+, the actual performance gain of Seq+ is likely to be even greater View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Refined triggering graphs: a logic-based approach to termination analysis in an active object-oriented database

    Publication Year: 1996 , Page(s): 384 - 391
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    Presents the notion of refined triggering graphs (RTG) for analyzing termination of active rules in object-oriented databases (OODBs). The RTG method consists of mapping the possibility that one active rule can trigger another to the satisfiability of a well-defined logic formula called a triggering formula. The unsatisfiability of the triggering formula is then an indication that the rule triggering possibility is nil. We identify three increasingly more powerful types of triggering formulae and give pointers to the corresponding satisfiability procedures View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.