The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
Kyuyoung Whang - One of the best experts on this subject based on the ideXlab platform.
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a formal framework for prefetching based on the type level access pattern in object relational dbmss
IEEE Transactions on Knowledge and Data Engineering, 2005Co-Authors: Kyuyoung Whang, Yangsae MoonAbstract:Prefetching is an effective method for minimizing the number of fetches between the client and the server in a Database management system. In this paper, we formally define the notion of prefetching. We also formally propose new notions of the type-level access locality and type-level access pattern. The type-level access locality is a phenomenon that repetitive patterns exist in the attributes referenced. The type-level access pattern is a pattern of attributes that are referenced in accessing the objects. We then develop an efficient capturing and prefetching policy based on this formal framework. Existing prefetching methods are based on object-level or page-level access patterns, which consist of object-ids or page-ids of the objects accessed. However, the drawback of these methods is that they work only when exactly the same objects or pages are accessed repeatedly. In contrast, even though the same objects are not accessed repeatedly, our technique effectively prefetches objects if the same attributes are referenced repeatedly, i.e., if there is type-level access locality. Many navigational applications in Object-Relational Database management systems (ORDBMSs) have type-level access locality. Therefore, our technique can be employed in ORDBMSs to effectively reduce the number of fetches, thereby significantly enhancing the performance. We also address issues in implementing the proposed algorithm. We have conducted extensive experiments in a prototype ORDBMS to show effectiveness of our algorithm. Experimental results using the 007 benchmark, a real GIS application, and an XML application show that our technique reduces the number of fetches by orders of magnitude and improves the elapsed time by several factors over on-demand fetching and context-based prefetching, which is a state-of-the-art prefetching method. These results indicate that our approach provides a new paradigm in prefetching that improves performance of navigational applications significantly and is a practical method that can be implemented in commercial ORDBMSs.
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prefetchguide capturing navigational access patterns for prefetching in client server object oriented object relational dbmss
Information Sciences, 2003Co-Authors: Yangsae Moon, Kyuyoung WhangAbstract:In prefetching, the objects that are expected to be accessed in the future are fetched from the server to the client in advance. Prefetching reduces the number of round-trips and increases the system performance. To prefetch object effectively, we need to correctly predict the future navigational patterns. In this paper, we propose the PrefetchGuide , a novel data structure that captures the navigational access patterns. We also formally define the notion of the attribute access log set and analyze the navigational access patterns that can be captured by the PrefetchGuide. We then present an prefetching algorithm using the PrefetchGuide. To show effectiveness of our algorithm, we have conducted extensive experiments in a prototype Object-Relational Database management systems (DBMS). The results show that our method significantly outperforms the state-of-the-art prefetching method. These results indicate that our approach provides a practical method that can be implemented in commercial object-oriented/Object-Relational DBMSs. We believe our method is practically usable for object-oriented programmers and DBMS implementors.
Yangsae Moon - One of the best experts on this subject based on the ideXlab platform.
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a formal framework for prefetching based on the type level access pattern in object relational dbmss
IEEE Transactions on Knowledge and Data Engineering, 2005Co-Authors: Kyuyoung Whang, Yangsae MoonAbstract:Prefetching is an effective method for minimizing the number of fetches between the client and the server in a Database management system. In this paper, we formally define the notion of prefetching. We also formally propose new notions of the type-level access locality and type-level access pattern. The type-level access locality is a phenomenon that repetitive patterns exist in the attributes referenced. The type-level access pattern is a pattern of attributes that are referenced in accessing the objects. We then develop an efficient capturing and prefetching policy based on this formal framework. Existing prefetching methods are based on object-level or page-level access patterns, which consist of object-ids or page-ids of the objects accessed. However, the drawback of these methods is that they work only when exactly the same objects or pages are accessed repeatedly. In contrast, even though the same objects are not accessed repeatedly, our technique effectively prefetches objects if the same attributes are referenced repeatedly, i.e., if there is type-level access locality. Many navigational applications in Object-Relational Database management systems (ORDBMSs) have type-level access locality. Therefore, our technique can be employed in ORDBMSs to effectively reduce the number of fetches, thereby significantly enhancing the performance. We also address issues in implementing the proposed algorithm. We have conducted extensive experiments in a prototype ORDBMS to show effectiveness of our algorithm. Experimental results using the 007 benchmark, a real GIS application, and an XML application show that our technique reduces the number of fetches by orders of magnitude and improves the elapsed time by several factors over on-demand fetching and context-based prefetching, which is a state-of-the-art prefetching method. These results indicate that our approach provides a new paradigm in prefetching that improves performance of navigational applications significantly and is a practical method that can be implemented in commercial ORDBMSs.
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prefetchguide capturing navigational access patterns for prefetching in client server object oriented object relational dbmss
Information Sciences, 2003Co-Authors: Yangsae Moon, Kyuyoung WhangAbstract:In prefetching, the objects that are expected to be accessed in the future are fetched from the server to the client in advance. Prefetching reduces the number of round-trips and increases the system performance. To prefetch object effectively, we need to correctly predict the future navigational patterns. In this paper, we propose the PrefetchGuide , a novel data structure that captures the navigational access patterns. We also formally define the notion of the attribute access log set and analyze the navigational access patterns that can be captured by the PrefetchGuide. We then present an prefetching algorithm using the PrefetchGuide. To show effectiveness of our algorithm, we have conducted extensive experiments in a prototype Object-Relational Database management systems (DBMS). The results show that our method significantly outperforms the state-of-the-art prefetching method. These results indicate that our approach provides a practical method that can be implemented in commercial object-oriented/Object-Relational DBMSs. We believe our method is practically usable for object-oriented programmers and DBMS implementors.
Thomas Seidl - One of the best experts on this subject based on the ideXlab platform.
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object relational spatial indexing
Spatial Databases, 2005Co-Authors: Hanspeter Kriegel, Martin Pfeifle, Marco Potke, Thomas Seidl, Jost EnderleAbstract:In order to generate efficient execution plans for queries comprising spatial data types and predicates, the Database system has to be equipped with appropriate index structures, query processing methods, and optimization rules. Although available extensible indexing frameworks provide a gateway for seamless integration of spatial access methods into the standard process of query optimization and execution, they do not facilitate the actual implementation of the spatial access method itself. An internal enhancement of the Database kernel is usually not an option for Database developers. The embedding of a custom block-oriented index structure into concurrency control, recovery services and buffer management would cause extensive implementation efforts and maintenance cost, at the risk of weakening the reliability of the entire system. The server stability can be preserved by delegating index operations to an external process, but this approach induces severe performance bottlenecks due to context switches and inter-process communication. Therefore, we present the paradigm of Object-Relational spatial access methods that perfectly fits to the common relational data model and is highly compatible with the extensible indexing frameworks of existing Object-Relational Database systems allowing the user to define application-specific access methods.
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spatial data management for virtual product development
Lecture Notes in Computer Science, 2003Co-Authors: Hanspeter Kriegel, Martin Pfeifle, Marco Potke, Matthias Renz, Thomas SeidlAbstract:In the automotive and aerospace industry, millions of technical documents are generated during the development of complex engineering products. Particularly, the universal application of Computer Aided Design (CAD) from the very first design to the final documentation created the need for transactional, concurrent, reliable, and secure data management. The huge underlying CAD Databases, occupying terabytes of distributed secondary and tertiary storage, are typically stored and referenced in Engineering Data Management systems (EDM) and organized by means of hierarchical product structures. Although most CAD files represent spatial objects or contain spatially related data, existing EDM systems do not efficiently support the evaluation of spatial predicates. In this paper, we introduce spatial Database technology into the file-based world of CAD. As we integrate 3D spatial data management into standard Object-Relational Database systems, the required support for data independence, transactions, recovery, and interoperability can be achieved. Geometric primitives, transformations, and operations on three-dimensional engineering data will be presented which are vital contributions to spatial data management for CAD Databases, Furthermore, we will present an effective and efficient approach to spatially index CAD data by using the concepts of Object-Relational Database systems and the techniques of relational access methods. The presented techniques are assembled to a complete system architecture for the Database Integration of Virtual Engineering (DIVE). By using relational storage structure, the DIVE system provides three-dimensional spatial data management within a commercial Database system. The spatial data management and the query processor is fully embedded into the Oracle8i server and has been evaluated in an industrial environment. Spatial queries on large Databases are performed at interactive response times.
Hanspeter Kriegel - One of the best experts on this subject based on the ideXlab platform.
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object relational spatial indexing
Spatial Databases, 2005Co-Authors: Hanspeter Kriegel, Martin Pfeifle, Marco Potke, Thomas Seidl, Jost EnderleAbstract:In order to generate efficient execution plans for queries comprising spatial data types and predicates, the Database system has to be equipped with appropriate index structures, query processing methods, and optimization rules. Although available extensible indexing frameworks provide a gateway for seamless integration of spatial access methods into the standard process of query optimization and execution, they do not facilitate the actual implementation of the spatial access method itself. An internal enhancement of the Database kernel is usually not an option for Database developers. The embedding of a custom block-oriented index structure into concurrency control, recovery services and buffer management would cause extensive implementation efforts and maintenance cost, at the risk of weakening the reliability of the entire system. The server stability can be preserved by delegating index operations to an external process, but this approach induces severe performance bottlenecks due to context switches and inter-process communication. Therefore, we present the paradigm of Object-Relational spatial access methods that perfectly fits to the common relational data model and is highly compatible with the extensible indexing frameworks of existing Object-Relational Database systems allowing the user to define application-specific access methods.
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spatial data management for virtual product development
Lecture Notes in Computer Science, 2003Co-Authors: Hanspeter Kriegel, Martin Pfeifle, Marco Potke, Matthias Renz, Thomas SeidlAbstract:In the automotive and aerospace industry, millions of technical documents are generated during the development of complex engineering products. Particularly, the universal application of Computer Aided Design (CAD) from the very first design to the final documentation created the need for transactional, concurrent, reliable, and secure data management. The huge underlying CAD Databases, occupying terabytes of distributed secondary and tertiary storage, are typically stored and referenced in Engineering Data Management systems (EDM) and organized by means of hierarchical product structures. Although most CAD files represent spatial objects or contain spatially related data, existing EDM systems do not efficiently support the evaluation of spatial predicates. In this paper, we introduce spatial Database technology into the file-based world of CAD. As we integrate 3D spatial data management into standard Object-Relational Database systems, the required support for data independence, transactions, recovery, and interoperability can be achieved. Geometric primitives, transformations, and operations on three-dimensional engineering data will be presented which are vital contributions to spatial data management for CAD Databases, Furthermore, we will present an effective and efficient approach to spatially index CAD data by using the concepts of Object-Relational Database systems and the techniques of relational access methods. The presented techniques are assembled to a complete system architecture for the Database Integration of Virtual Engineering (DIVE). By using relational storage structure, the DIVE system provides three-dimensional spatial data management within a commercial Database system. The spatial data management and the query processor is fully embedded into the Oracle8i server and has been evaluated in an industrial environment. Spatial queries on large Databases are performed at interactive response times.
Tetsuya Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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query by object interface for information requirement elicitation in m commerce
International Journal of Human-computer Interaction, 2006Co-Authors: Shapiee Abd Rahman, Subhash Bhalla, Tetsuya HashimotoAbstract:Information Requirement Elicitation (IRE) is essential in wireless Web service to elicit information requirements through interactive choice prompts. This article presents a design of a high-level user interface for IRE, in the context of banking Database queries by a mobile Web user. The prototype is based on the notion of a Query-By-Object approach of building a query using multiple user-level steps. The test prototype system uses the Mobile Information Devices Profile of the Java 2 Platform, Micro Edition, for a wireless front end, and a Java 2 Platform, Enterprise Edition, application server and an Object-Relational Database Management System at the back end. An empirical study conducted on the prototype has demonstrated that the proposed user interface is intuitive and simple to use. The proposed interface aims to eliminate ambiguities in users' communication by virtue of a step-by-step procedure. The main contributions of this interface are its simplicity to express a query and its expressive power.
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query by object interface for information requirement elicitation in m commerce
Congress on Evolutionary Computation, 2005Co-Authors: Shapiee Abd Rahman, Subhash Bhalla, Tetsuya HashimotoAbstract:Information requirement elicitation (IRE) is essential in wireless Web service to elicit information requirements through interactive choice prompts. We present a design of a high-level user interface for IRE, in the context of 'banking Database queries' by a mobile Web user. The prototype is based on the notion of query-by object (QBO) approach of building a query using multiple user-level steps. The test prototype system uses J2ME MIDP for a wireless front end and a J2EE application server and an Object-Relational Database management system (ORDBMS) at the back end. A sample set of queries demonstrate ease of access by the users. Ambiguities in users' intentions are eliminated by virtue of a step-by-step procedure.
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Query-by-object interface for dynamic access and information requirement elicitation
4th Annual International Conference on Mobile Business ICMB 2005, 2005Co-Authors: Shapiee Abd Rahman, Suresh Bhalla, Tetsuya HashimotoAbstract:Information Requirement Elicitation (IRE) is essential in wireless web service to elicit information requirements through interactive choice prompts. We present a high-level user interface for an IRE-enabled information system, in the context of Database queries by a mobile web user. The prototype is based on the notion of a Query-By-Object (QBO) approach of building a query using multiple user-level steps. The test prototype system uses the Mobile Information Devices Profile (MIDP) of the Java 2 Platform, Micro Edition (J2ME), for a wireless front end, and a Java 2 Platform, Enterprise Edition (J2EE) application server and an Object-Relational Database Management System (ORDBMS) at the back end. A sample set of dynamic queries demonstrate ease of use by the users.
