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Data Engineering, 1997. Proceedings. 13th International Conference on

Date 7-11 April 1997

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  • Proceedings 13th International Conference on Data Engineering

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  • Databases and the Web: What's in it for Databases?

    Page(s): 192
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    Freely Available from IEEE
  • Data Mining: Where Is It Heading? (Panel)

    Page(s): 508
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    Freely Available from IEEE
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  • Index of authors

    Page(s): 591 - 592
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  • A priority ceiling protocol with dynamic adjustment of serialization order

    Page(s): 552 - 561
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    The difficulties of providing a guarantee of meeting transaction deadlines in hard real-time database systems lie in the problems of priority inversion and of deadlocks. Priority inversion and deadlock problems ensue when concurrency control protocols are adapted in priority-driven scheduling. The blocking delay due to priority inversion can be unbounded, which is unacceptable in the mission-critical real-time applications. Some priority ceiling protocols have been proposed to tackle these two problems. However, they are too conservative in scheduling transactions for the single-blocking and deadlock-free properties, leading to many unnecessary transaction blockings. The authors analyze the unnecessary transaction blocking problem inherent in these priority ceiling protocols and investigate the conditions for allowing a higher priority transaction to preempt a lower priority transaction using the notion of dynamic adjustment of serialization order. A new priority ceiling protocol is proposed to solve the unnecessary blocking problem, thus enhancing schedulability. They also devise the worst-case schedulability analysis for the new protocol which provides a better schedulability condition than other protocols View full abstract»

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  • Pinwheel scheduling for fault-tolerant broadcast disks in real-time database systems

    Page(s): 543 - 551
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    The design of programs for broadcast disks which incorporate real-time and fault-tolerance requirements is considered. A generalized model for real-time fault-tolerant broadcast disks is defined. It is shown that designing programs for broadcast disks specified in this model is closely related to the scheduling of pinwheel task systems. Some new results in pinwheel scheduling theory are derived, which facilitate the efficient generation of real-time fault-tolerant broadcast disk programs View full abstract»

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  • Object Relater Plus: a practical tool for developing enhanced object databases

    Page(s): 412 - 421
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    Object Relater Plus is a practical tool currently being used for research and development of enhanced object databases (ODBs). The tool, which is a prototype object database management system (ODBMS), provides two languages that are compatible with the ODMG-93 ODBMS standard yet enhance it in some significant ways. The Object Database Definition Language (ODDL) allows object relationships to be better defined and supported; provides for the specification and separation of external, conceptual, and internal views; and facilitates the implementation of domain specific ODB extensions. The Object Database Manipulation Language (ODML) augments ODDL by providing a C++ interface for database creation, access, and manipulation based on an ODDL specification. We give an overview of Object Relater Plus, emphasizing its salient features. We also briefly discuss its architecture and implementation and its use in developing scientific databases View full abstract»

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  • Titan: a high-performance remote-sensing database

    Page(s): 375 - 384
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    There are two major challenges for a high performance remote sensing database. First, it must provide low latency retrieval of very large volumes of spatio temporal data. This requires effective declustering and placement of a multidimensional dataset onto a large disk farm. Second, the order of magnitude reduction in data size due to post processing makes it imperative, from a performance perspective, that the post processing be done on the machine that holds the data. This requires careful coordination of computation and data retrieval. The paper describes the design, implementation and evaluation of Titan, a parallel shared nothing database designed for handling remote sensing data. The computational platform for Titan is a 16 processor IBM SP-2 with four fast disks attached to each processor. Titan is currently operational and contains about 24 GB of AVHRR data from the NOAA-7 satellite. The experimental results show that Titan provides good performance for global queries and interactive response times for local queries View full abstract»

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  • Clustering association rules

    Page(s): 220 - 231
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    The authors consider the problem of clustering two-dimensional association rules in large databases. They present a geometric-based algorithm, BitOp, for performing the clustering, embedded within an association rule clustering system, ARCS. Association rule clustering is useful when the user desires to segment the data. They measure the quality of the segmentation generated by ARCS using the minimum description length (MDL) principle of encoding the clusters on several databases including noise and errors. Scale-up experiments show that ARCS, using the BitOp algorithm, scales linearly with the amount of data View full abstract»

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  • Similarity based retrieval of videos

    Page(s): 181 - 190
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    The authors propose a language, called Hierarchical Temporal Logic (HTL), for specifying queries on video databases. The language is based on the hierarchical as well as temporal nature of video data. They give similarity based semantics for the logic, and give efficient methods for computing similarity values for subclasses of HTL formulas. Experimental results, indicating the effectiveness of the methods, are presented View full abstract»

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  • Graphical tools for rule development in the active DBMS SAMOS

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    Summary form only given. Active database management systems (active DBMS) support the definition, management and execution of event/condition/action rules specifying reactive application behavior. Although the advantages of active mechanisms are nowadays well known, there is still no wide use in practice. One main problem is that especially for large rule sets, defined by different persons at different points in time, potential conflicts and dependencies between rules are hard to predict and rule behavior is difficult to control. Therefore, tools are needed to assist the development and maintenance of rule bases. These tools should provide for graphical interfaces supporting both, “static” activities (performed during rule specification) such as rule editing, browsing, design, rule analysis, and “dynamic” activities (performed at runtime, during the execution of an application) such as testing, debugging and understanding of rule behavior. The aim of the article is to show the use of three of these tools, namely the rule editor, the browser and the termination analyzer in the process of developing applications for the active object oriented DBMS SAMOS View full abstract»

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  • Periodic retrieval of videos from disk arrays

    Page(s): 333 - 343
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    A growing number of applications need access to video data stored in digital form on secondary storage devices (e.g., video-on-demand, multimedia messaging). As a result, video servers that are responsible for the storage and retrieval, at fixed rates, of hundreds of videos from disks are becoming increasingly important. Since video data tends to be voluminous, several disks are usually used in order to store the videos. A challenge is to devise schemes for the storage and retrieval of videos that distribute the workload evenly across disks, reduce the cost of the server and at the same time, provide good response times to client requests for video data. In this paper we present schemes that retrieve videos periodically from disks in order to provide better response times to client requests. We present two schemes that stripe videos across multiple disks in order to distribute the workload uniformly among them. For the two striping schemes, we show that the problem of retrieving videos periodically is equivalent to that of scheduling periodic tasks on a multiprocessor. For the multiprocessor scheduling problems, we present and compare schemes for computing start times for the tasks, if it is determined that they are schedulable View full abstract»

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  • Integrated query processing strategies for spatial path queries

    Page(s): 477 - 486
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    Investigates optimization strategies for processing path queries with embedded spatial constraints, such as avoiding areas with certain characteristics. To resolve complex spatial constraints during path finding, we consider two decisions: (1) the spatial relation operations (e.g. intersection) between areas and links can be pre-processed or intermixed with path-finding, and (2) areas satisfying the query constraint can be pre-filtered or dynamically selected during path-finding. Based on these two decisions, we propose and implement the resulting four integrated query processing strategies, utilizing state-of-the-art technologies such as spatial joins for intersect computation, R-tree access structure for spatial overlap searching, and spatial clustering for efficient path searching. In this paper, we also report an experimental evaluation to show which strategies perform best in different scenarios View full abstract»

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  • A propagation mechanism for populated schema versions

    Page(s): 67 - 78
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    Object-oriented database systems (OODBMS) offer powerful modeling concepts as required by advanced application domains like CAD/CAM/CAE or office automation. Typical applications have to handle large and complex structured objects which frequently change their value and their structure. As the structure is described in the schema of the database, support for schema evolution is a highly required feature. Therefore, a set of schema update primitives must be provided which can be used to perform the required changes, even in the presence of populated databases and running applications. In this paper, we use the versioning approach to schema evolution to support schema updates as a complex design task. The presented propagation mechanism is based on conversion functions that map objects between different types and can be used to support schema evolution and schema integration View full abstract»

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  • The multikey type index for persistent object sets

    Page(s): 22 - 31
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    Multikey index structures for type hierarchies are a recently discussed alternative to traditional B+-tree indexing schemes. We describe an efficient implementation of this alternative called the multikey type index (MT-index). A prerequisite for our approach is an optimal linearization of the type hierarchy that allows us to map queries in object type hierarchies to minimal-volume range queries in multi-attribute search structures. This provides access to an already-existing large and versatile tool-box. The outline of an index implementation by means of a multi-attribute search structure (e.g. the hB-tree or any other structure with comparable performance) is followed by an analytical performance evaluation. Selected performance figures are compared to previous approaches, in particular to the H-tree and the class hierarchy tree. The comparison results allow for practically relevant conclusions with respect to index selection based on query profiles View full abstract»

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  • Improving the quality of technical data for developing case based reasoning diagnostic software for aircraft maintenance

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    Summary form only given. Time spent by airline maintenance operators to solve engine failures and the related costs (flight delays or cancellations) are a major concern to SNECMA which manufacture engines for civilian aircraft such as BOEING 737s and Airbus A340s. The use of an intelligent diagnostic software contributes to improving customer support and reduces the cost of ownership by improving troubleshooting accuracy and reducing airplane downtime. However, classical rule based or model based expert systems are costly to develop and maintain. Our goal has been to improve the development of troubleshooting systems through case based reasoning (CBR) and data mining. These technologies reason from past cases, whose solution is known, rather than rules. New problems are solved by searching for similar problem solving experiences and by adapting the solutions that worked in the past, Our second objective was to acquire the capacity to produce systems which match the quality standard in the aeronautic industry in the given time frame. We aim at both assuring the quality of the core data mining and CBR software as well as the quality of the technical information that is fed into the system (case knowledge) View full abstract»

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  • High-dimensional similarity joins

    Page(s): 301 - 311
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    Many emerging data mining applications require a similarity join between points in a high-dimensional domain. We present a new algorithm that utilizes a new index structure, called the ε-kdB tree, for fast spatial similarity joins on high-dimensional points. This index structure reduces the number of neighboring leaf nodes that are considered for the join test, as well as the traversal cost of finding appropriate branches in the internal nodes. The storage cost for internal nodes is independent of the number of dimensions. Hence the proposed index structure scales to high-dimensional data. Empirical evaluation, using synthetic and real-life datasets, shows that similarity join using the ε-kdB tree is 2 to an order of magnitude faster than the R+ tree, with the performance gap increasing with the number of dimensions View full abstract»

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  • Data integration and interrogation

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    Summary form only given. One major concern of the Verso group at Inria is the development of technology for data integration and interrogation, especially for non traditional data formats such as structured text. The article describes aspects of Verso's technology as partly sponsored by the European Community (AQUARELLE project, Esprit IV projects OPAL and WIRE) View full abstract»

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  • Failure handling for transaction hierarchies

    Page(s): 245 - 254
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    Previously, failure recovery mechanisms have been developed separately for nested transactions and for transactional workflows specified as “flat” flow graphs. The paper develops unified techniques for complex business processes modeled as cooperative transaction hierarchies. Multiple cooperative transaction hierarchies often have operational dependencies, thus a failure occurring in one transaction hierarchy may need to be transferred to another. The existing transaction models do not support failure handling across transaction hierarchies. The authors introduce the notion of transaction execution history tree which allows one to develop a unified hierarchical failure recovery mechanism applicable to both nested and flat transaction structures. They also develop a cross-hierarchy undo mechanism for determining failure scopes and supporting backward and forward failure recovery over multiple transaction hierarchies. These mechanisms form a structured and unified approach for handling failures in flat transactional workflows, along a transaction hierarchy, and across transaction hierarchies View full abstract»

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  • The CORD approach to extensible concurrency control

    Page(s): 562 - 571
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    Database management systems (DBMSs) have been increasingly used for advanced application domains, such as software development environments, workflow management systems, computer-aided design and manufacturing, and managed healthcare. In these domains, the standard correctness model of serializability is often too restrictive. The authors introduce the notion of a concurrency control language (CCL) that allows a database application designer to specify concurrency control policies to tailor the behavior of a transaction manager. A well-crafted set of policies defines an extended transaction model. The necessary semantic information required by the CCL run-time engine is extracted from a task manager, a (logical) module by definition included in all advanced applications. This module stores task models that encode the semantic information about the transactions submitted to the DBMS. They have designed a rule-based CCL, called CORD, and have implemented a run-time engine that can be hooked to a conventional transaction manager to implement the sophisticated concurrency control required by advanced database applications. They present an architecture for systems based on CORD and describe how they integrated the CORD engine with the Exodus Storage Manager to implement altruistic locking View full abstract»

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  • Active customization of GIS user interfaces

    Page(s): 487 - 496
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    Presents a new approach to user interface customization in geographic information systems (GIS). This approach is based on the integration of three main components: a GIS user interface architecture; an active database mechanism; and a generic interface builder. The GIS interface architecture provides the default interface behavior, while the active system allows customization of interfaces according to the specific context. The generic interface builder relies on a library of interface objects to dynamically construct generic and customized interfaces. The main advantage of this approach is that it decreases the costs associated with developing customized GIS interfaces View full abstract»

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  • Developing and accessing scientific databases with the OPM data management tools

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    Summary form only given. The Object-Protocol Model (OPM) data management tools provide facilities for rapid development, documentation, and flexible exploration of scientific databases. The tools are based on OPM, an object-oriented data model which is similar to the ODMG standard, but also supports extensions for modeling scientific data. Databases designed using OPM can be implemented using a variety of commercial relational DBMSs, using schema translation tools that generate complete DBMS database definitions from OPM schemas. Further, OPM schemas can be retrofitted on top of existing databases defined using a variety of notations, such as the relational data model or the ASN.1 data exchange format, using OPM retrofitting tools. Several archival molecular biology databases have been designed and implemented using the OPM tools, including the Genome Database (GDB) and the Protein Data Bank (PDB), while other scientific databases, such as the Genome Sequence Database (GSDB), have been retrofitted with semantically enhanced views using the OPM tools View full abstract»

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  • Quantifying complexity and performance gains of distributed caching in a wireless network environment

    Page(s): 104 - 113
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    In a mobile computing system, the wireless communication bandwidth is a scarce resource that needs to be managed carefully. In this paper, we investigate the use of distributed caching as an approach to reduce the wireless bandwidth consumption for data access. We find that conventional caching techniques cannot fully utilize the dissemination feature of the wireless channel. We thus propose a novel distributed caching protocol that can minimize the overall system bandwidth consumption at the cost of CPU processing time at the server side. This protocol allows the server to select data items into a broadcast set, based on a performance gain parameter called the bandwidth gain, and then send the broadcast set to all the mobile computers within the server's cell. We show that in general, this selection process is NP-hard, and therefore we propose a heuristic algorithm that can attain a near-optimal performance. We also propose an analytical model for the protocol and derive closed-form performance measures, such as the bandwidth utilization and the expected response time of data access by mobile computers. Experiments show that our distributed caching protocol can greatly reduce the bandwidth consumption so that the wireless network environment can accommodate more users and, at the same time, vastly improve the expected response time for data access by mobile computers View full abstract»

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  • Teaching an OLTP database kernel advanced datawarehousing techniques

    Page(s): 194 - 198
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    Most, if not all, of the major commercial database products available today were written more than 10 years ago. Their internal designs have always been heavily optimized for OLTP applications. Over the last couple of years as DSS and data warehousing have become more important, database companies have attempted to increase their performance with DSS-type applications. Most of their attempts have been in the form of added features like parallel table scans and simple bitmap indexing techniques. These were chosen because they could be quickly implemented (1-2 years), giving some level of increased query performance. The paper contends that the real performance gains for the DSS application have not yet been realized. The performance gains for DSS will not come from parallel table scans, but from major changes to the low level database storage management used by OLTP systems. One Sybase product, Sybase-IQ has pioneered some of these new techniques. The paper discusses a few of these techniques and how they could be integrated into an existing OLTP database kernel View full abstract»

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