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1999 international symposium on Database Applications in Non-Traditional Environments, DANTE 1999

作者： Fang, Qiang Wang, Giiorcn Yu, Go Kanoko, Kimihiko Makinouchi, Akifumi School of Information Science and Engineering Northeastern University Shenyang110006 China Graduate School of Information Science and Electrical Engineering Kyushu University Fuknoka812 Japan

ISBN: (纸本)0769504965

In OODB, path expressions are usually used for navigating through complex objects and obtaining necessary information at the far end of a sequence of object *** parallel forward pointer chasing algorithm (PFPC) and parallel backward pointer algorithm (PBPC) are natural algorithms for path *** we change the implicit joins in the path expression into explicit joins, parallel join algorithms can also be employed for path *** order to improve performance in a distributed environment, semi-join operations replace the join operations, which is called the parallel cascade semi-join algorithm (PCSJ).This paper mainly describes and compares PFPC and PCSJ algorithms implemented on DSVM;then analyzes the performance of algorithms from test results according to a certain *** can see PCSJ has much better performance than PFPC by the *** parallel algorithms exploit pipelining and I/O communication parallelism;making full use of DSVM *** valuable ideas are obtained from the theory analysis and practical testing © 2000 IEEE.

关键词： Object-oriented databases

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Implementation of a virtual time synchronizer for distributed databases

Proceedings of the International Parallel Processing Symposi...

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proceedings of the international parallel Processing symposium, IPPS 1999年 733-737页

作者： Boukerche, Azzedine Das, Sajal K. Datta, Ajoy LeMaster, Timothy E. Univ of North Texas Denton United States

The availability of high speed networks and improved microprocessor performance have made it possible to build inexpensive cluster of workstations as an appealing platform for parallel and distributed computing. In this paper, we study the performance of a distributed database system synchronized by virtual time (VT) mechanism by experimenting on a LAN-connected collection of 12 Sun-SPARCS workstations. Our experimental results demonstrate that the VT synchronization protocol is a viable concurrency control method, and it yields about 25-30% reduction in the response time, when compared with a widely used, multiversion (MV) concurrency control scheme based on timestamps order. The reason for comparing with the MV approach is that both virtual time and multiversion protocols are based upon the concept of timestamps, and attain high performance by using multiple version of the data objects.

关键词： distributed database systems

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Evaluation of active disks for decision support databases

Evaluation of active disks for decision support databases

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The 6th international symposium on High-Performance Computer Architecture (HPCA-6)

作者： Uysal, Mustafa Acharya, Anurag Saltz, Joel HP Labs Palo Alto United States

Growth and usage trends for large decision support databases indicate that there is a need for architectures that scale the processing power as the dataset grows. To meet this need, several researchers have recently proposed Active Disk architectures which integrate substantial processing power and memory into disk units. In this paper, we evaluate Active Disks for decision support databases. First, we compare the performance of Active Disks with that of existing scalable server architectures: SMP-based conventional disk farms and commodity clusters of PCs. second, we evaluate the impact of several design choices on the performance of Active Disks. We focus on the performance impact of interconnect bandwidth, amount of disk memory and disk-to-disk communication architecture on decision support workloads. Our results show that for identical disks, number of processors and I/O interconnect, Active Disks provide better price/performance than both SMP-based conventional disk farms and commodity clusters. Experiments evaluating the impact of design alternatives in Active Disk architectures indicate that: (1) for configurations up to 64 disks, a dual fibre channel arbitrated loop interconnect is sufficient even for the most communication-intensive decision support tasks;(2) most decision support tasks do not require a large amount of memory;and (3) direct disk-to-disk communication is necessary for achieving good performance on tasks that repartition all (or a large fraction of) their dataset.

关键词： parallel processing systems

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Object-oriented design of adaptive multicast communications

Object-oriented design of adaptive multicast communications

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international symposium on parallel Architectures, Algorithms and Networks (ISPAN)

作者： Weiming Zhang Weijia Jia Department of Computer Science City University Hong Kong China

Multicast (group) communications have been widely recognized by current research and industry. Multicast is very useful for various network applications such as distributed (replicated) database, video/audio conference, information distribution and server locations etc. But design and implementation of such multicast communication systems in networks are complicated tasks, especially when quality of service (QoS) of applications such as real time and reliability are desired. In order to quickly design and implement multicast communication, good tools are crucial and must be facilitated. The paper presents a novel object oriented (OO) QoS driven approach for the quick design and prototyping of multicast communication systems under certain QoS requirements, for multicast message transmission and receptions such as real time, total ordering, atomicity and fault tolerance etc.

关键词： Multicast communication Quality of service Real time systems Communication industry distributed databases Object oriented databases Audio databases Videoconference Network servers Telecommunication network reliability

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Implementation of a virtual time synchronizer for distributed databases

Implementation of a virtual time synchronizer for distribute...

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international symposium on parallel Processing

作者： A. Boukerche S.K. Das A. Datta T.E. LeMaster Department of Computer Science University of North Texas Denton TX USA Department of Computer Science University of Nevada Las Vegas NV USA

关键词： distributed databases Database systems Protocols Workstations Concurrency control Computer science distributed computing Object oriented modeling Concurrent computing System recovery

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parallel algorithms for 3D reconstruction of asymmetric objects from electron micrographs

Parallel algorithms for 3D reconstruction of asymmetric obje...

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international symposium on parallel Processing

作者： R.E. Lynch D.C. Marinescu H. Lin T.S. Baker Department of Computer Sciences Purdue University USA

We present new parallel algorithms for 3D reconstruction of objects from 2D projections and their application for the determination of the structure of macromolecules from electron micrographs. A multi-resolution orientation determination algorithm uses a parallel search to determine the 'best fit' of a given image with images in a reference database. The 3D reconstruction algorithm uses Cartesian coordinates and permits the reconstruction of objects that do not possess symmetries. The method decomposes a large linear system into a set of smaller systems that can be solved independently on different processors of a parallel computer or on a cluster of workstations. The paper outlines the reconstruction process and the data partitioning and load balancing issues pertinent to the parallel implementation of the algorithm; preliminary results obtained on a SGI Origin 2000 system are given.

关键词： parallel algorithms Image reconstruction Electrons Position measurement Image databases Object oriented databases Reconstruction algorithms Linear systems Concurrent computing Workstations

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Oblivious deadlock-free routing in a faulty hypercube

Proceedings of the International Parallel Processing Symposi...

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proceedings of the international parallel Processing symposium, IPPS 1999年 312-319页

作者： Kim, Jin Suk Lehman, Eric Leighton, Tom Massachusetts Inst of Technology Cambridge United States

A central problem in massively parallel computing is efficiently routing data between processors. This problem is complicated by two considerations. First, in any massively parallel system, some processors are bound to fail, disrupting message routing. second, one must avoid deadlock configurations in which messages permanently block one another. We present an efficient, oblivious, and deadlock-free routing algorithm for the hypercube. The algorithm tolerates a large number of faults in a worst-case configuration.

关键词： parallel processing systems

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Design and implementation of a scalable parallel system for multidimensional analysis and OLAP

Design and implementation of a scalable parallel system for ...

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international symposium on parallel Processing

作者： S. Goil A. Choudhary Department of Electrical & Computer Engineering Technological Institute Northwestern University Evanston IL USA

Multidimensional Analysis and On-Line Analytical Processing (OLAP) uses summary information that requires aggregate operations along one or more dimensions of numerical data values. Query processing for these applications require different views of data for decision support. The Data Cube operator provides multi-dimensional aggregates, used to calculate and store summary information on a number of dimensions. The multi-dimensionality of the underlying problem can be represented both in relational and multi-dimensional databases, the latter being a better fit when query performance is the criteria for judgment. Relational databases are scalable in size and efforts are on to make their performance acceptable. On the other hand multi-dimensional databases perform well for such queries, although they are nor very scalable. parallel computing is necessary to address the scalability and performance issues for these data sets. In this paper we present a parallel and scalable infrastructure for OLAP and multidimensional analysis. We use chunking to store data either as a dense block using multidimensional arrays (md-arrays) or a sparse set using a Bit encoded sparse structure (BESS). Chunks provide a multidimensional index structure for efficient dimension oriented data accesses much the same as md-arrays do. Operations within chunks and between chunks are a combination of relational and multi-dimensional operations depending on whether the chunk is sparse or dense. We present performance results for data sets with 3, 5 and 10 dimensions for our implementation on the IBM SP-2 which show good speedup and scalability.

关键词： Multidimensional systems databases Data structures Aggregates Information analysis Decision support systems Data mining Performance analysis

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LLB: A fast and effective scheduling algorithm for distributed-memory systems

Proceedings of the International Parallel Processing Symposi...

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proceedings of the international parallel Processing symposium, IPPS 1999年 525-530页

作者： Radulescu, Andrei van Gemund, Arjan J.C. Lin, Hai-Xiang Delft Univ of Technology Delft Netherlands

This paper presents a new algorithm called List-based Load Balancing (LLB) for compile-time task scheduling on distributed-memory machines. LLB is intended as a cluster-mapping and task-ordering step in the multi-step class of scheduling algorithms. Unlike current multistep approaches, LLB integrates cluster-mapping and task-ordering in a single step. The benefits of this integration are twofold. First, it allows dynamic load balancing in time, because only the ready tasks are considered in the mapping process. second, communication is also considered, as opposed to algorithms like WCM and GLB. The algorithm has a low time complexity of O(E+V(log V+log P)), where E is the number of dependences, V is the number of tasks and P is the number of processors. Experimental results show that LLB outperforms known cluster-mapping algorithms of comparable complexity, improving the schedule lengths up to 42%. Furthermore, compared with LCA, a much higher-complexity algorithm, LLB obtains comparable results for fine-grain graphs and yields improvements up to 16% for coarse-grain graphs.

关键词： parallel processing systems

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parallelizing user-defined functions in distributed object-relational DBMS

Parallelizing user-defined functions in distributed object-r...

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international symposium on Database Engineering and Applications (IDEAS)

作者： K.W. Ng R.R. Muntz Computer Science Department University of California Los Angeles CA USA

Full support of parallelism in object-relational database systems (ORDBMSs) is desired. The parallelization techniques developed for relational database systems are not adequate for ORDBMS because of the introduction of complex abstract data types and operations on ordered domains. In this paper, we consider a data stream paradigm and develop a query parallelization framework that exploits characteristics of user-defined functions in a ORDBMS during query optimization. By introducing the concept of windows and abstract data type orderings, we develop a novel approach for parallelizing user-defined functions in a distributed ORDBMS environment. The implementation issues in providing query services in ordered domains are also discussed.

关键词： Relational databases parallel processing Query processing Computer science Database systems Image databases Data analysis Image processing Geoscience Information systems

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