Multiple processors are employed to improve the performance of database systems and the parallelism can be exploited at three levels in query processing: intra-operation, inter-operation, and inter-query parallelism. ...
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Multiple processors are employed to improve the performance of database systems and the parallelism can be exploited at three levels in query processing: intra-operation, inter-operation, and inter-query parallelism. Intra-operation and inter-operation parallelism are also called intra-query parallelism which has been studied extensively. In contrast, inter-query parallelism has received little attention particularly for multiple dependent queries. We develop a decompression algorithm, CPS, for coping with multiple dependent queries which are represented by a directed graph, and the algorithm makes use of the activity analysis of critical path analysis, and the resource scheduling and levelling of project management. A simulation study has been conducted and the results show that the proposed algorithm outperforms other existing methods and is able to provide a global optimal solution when the number of processors available is sufficient.
Rapid advances in high performance computing (HPC) and the Internet are heralding a paradigm shift to network-based scientific software servers, libraries, repositories and problem solving environments. According to t...
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Rapid advances in high performance computing (HPC) and the Internet are heralding a paradigm shift to network-based scientific software servers, libraries, repositories and problem solving environments. According to this new paradigm, vital pieces of software and information required for a computation are distributed across a network and need to be identified and 'linked' together at run time; this implies a 'net-centric' and collaborative scenario for scientific computing. This scenario requires the application to dynamically choose the best among several competing resources that can solve a given problem. For these systems to become ubiquitous, efficient mechanisms for collaboration and automatic inference of the abilities of multiple 'compute servers' need to be established. The authors demonstrate a methodology to facilitate collaborative scientific computing. Their idea is comprised of (i) a concept of 'reasonableness' to automatically generate exemplars for learning the mapping from problems to 'servers' and (ii) a neuro-fuzzy technique developed earlier by the authors that conducts supervised classification on the exemplars generated. The techniques work in an on-line manner and cater to mutually non-exclusive classes which are critical in the collaborative networked computing landscape.
The RDT network router chip is a versatile router for the massively parallel computer prototype JUMP-1. The major goal of this project is to establish techniques for building an efficient distributed shared memory on ...
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The RDT network router chip is a versatile router for the massively parallel computer prototype JUMP-1. The major goal of this project is to establish techniques for building an efficient distributed shared memory on a massively parallel processor. For this purpose, the reduced hierarchical bit-map directory (RHBD) schemes are used for efficient cache management of the distributed shared memory. In order to implement (RHBD) schemes efficiently, we proposed a novel interconnection network RDT (recursive diagonal torus), and developed a sophisticated router chip for the RDT which equips a hierarchical multicast mechanism without deadlock and acknowledge combining mechanism. By using the 0.5/spl mu/BiCMOS SOG technology it can transfer all packets synchronized with a unique CPU clock(60MHz). Long coaxial cables are directly driven with the ECL interface of this chip. The mixed design approach with schematic and VHDL permits the development of the complicated chip with 90,522 gates in a year.
More reliable and a respective better power quality are the main requirements for any power supply system operating for a distributed power network, an industrial plant or, in a more particular case, for a train drive...
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More reliable and a respective better power quality are the main requirements for any power supply system operating for a distributed power network, an industrial plant or, in a more particular case, for a train drive. A new algorithm to decide, compute and analyze a compensation method that improves the power system performance is proposed, based on a complex bilinear model of two parallel connected voltage-type power converters. Analysis is performed for normal and faulted operation, with emphasis on the combined purposes-input currents' quality and system's reliability. A specially computed term is used for the feedback compensation and an optimum parameter identification is explained providing a strong basis for a unified theory of analysis for hybrid bilinear (biconnected) systems. It is proved that the method acts automatically for any of the analyzed operation conditions, and an experimental approach proves the theoretical analysis.
The primary goal of metacomputing is to integrate different computers, with different capabilities, into one unit, one large virtual computer (a metacomputer) capable of solving problems of unprecedented complexity. T...
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The primary goal of metacomputing is to integrate different computers, with different capabilities, into one unit, one large virtual computer (a metacomputer) capable of solving problems of unprecedented complexity. The whole task is controlled from microprocessor-based workstations, which also take care of all scalar (non-vectorized, non-parallelized) computations. The results of computation obtained so far are immediately displayed on several high-end graphic workstations, allowing different researchers to simultaneously inspect different aspects of the whole complex computation. A metacomputer, as a representative of the metacomputing paradigm, allows simplified access to centralized services at geographically different sites, joining them into a virtual parallel supercomputer. A personalized computing environment may be freely moved between researchers, increasing both their mobility and the efficiency of the computing resource utilization. Also, the metacomputing paradigm increases the efficient use of computers and their installed software (local mastery in some software packages is becoming available to a much larger community). Last but not least, the metacomputer enhances robustness-users at an individual site may continue in their work even in case of the failure of their local node.
We have been investigating the efficiency of genetic algorithms (GA) for solving for a variety of real problems. During our investigations we have concluded that the large amount of computational time required to find...
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We have been investigating the efficiency of genetic algorithms (GA) for solving for a variety of real problems. During our investigations we have concluded that the large amount of computational time required to find GA based solutions on conventional computers is restrictive. We are therefore developing an innovative new computer architecture, suitable for the solution of large scale problems using GAs. In this paper we introduce the SIMD-GA (Single Instruction stream Multiple Data stream Genetic Algorithm), and discuss its hardware design and implementation. By taking advantage of the recent advances is HDLs (Hardware Description Language) and FPGAs (Field Programmable Gate Array) we have been able to quickly develop and prototype a PE (Processing Element) for a SIMD-GA. This approach allows us to build a cost-effective parallel processing architecture to overcome the problem of the computational time required for traditional sequential GA implementation.
Cache-coherent multiprocessors with distributed shared memory are becoming increasingly popular for parallelcomputing. However, obtaining high performance on these machines mquires that an application execute with go...
ISBN:
(纸本)9780897919074
Cache-coherent multiprocessors with distributed shared memory are becoming increasingly popular for parallelcomputing. However, obtaining high performance on these machines mquires that an application execute with good data locality. In addition to making efiective use of caches, it is often necessary to distribute data structures across the local memories of the processing nodes, thereby reducing the latency of cache *** have designed a set of abstractions for performing data distribution in the context of explicitly parallel programs and implemented them within the SGI MIPSpro compiler system. Our system incorporates many unique features to enhance both programmability and performance. We address the former by providing a very simple programmming model with extensive support for error detection. Regarding performance, we carefully design the user abstractions with the underlying compiler optimizations in mind, we incorporate several optimization techniques to generate efficient code for accessing distributed data, and we provide a tight integration of these techniques with other optimizations within the compiler Our initial experience suggests that the directives are easy to use and can yield substantial performance gains, in some cases by as much as a factor of 3 over the same codes without distribution.
Recent advances in multimedia has necessitated us to look for an effective search method of images. Most of the contemporary indexing methods are based on color distribution in the images. When the users do not rememb...
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ISBN:
(纸本)9780818678257
Recent advances in multimedia has necessitated us to look for an effective search method of images. Most of the contemporary indexing methods are based on color distribution in the images. When the users do not remember the colors clearly, however, it has been difficult to retrieve the desired images. The paper proposes an indexing method based on shapes contained in an image. We characterize an image by the half planes that contain the objects in it. We also propose a method to characterize images by the vanishing points of parallel lines contained in an image. The vanishing points represent how three dimensional (3D) objects are projected onto the 2D image.
Automatic analysis and recognition of documents is a complex task. Substantial research effort has therefore been spent addressing sub-tasks of manageable size. The solutions, however, have to be integrated into a com...
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Automatic analysis and recognition of documents is a complex task. Substantial research effort has therefore been spent addressing sub-tasks of manageable size. The solutions, however, have to be integrated into a comprehensive engine. Following the idea of a toolbox a software architecture has been developed that enables various tools to be combined into a network of cooperating recognition algorithms. Distributing the tools on a number of processors improves overall performance by parallel execution. The configuration of the tools as well as the connections between them can easily be modified even at run-time. Simple, interactive access to the various parameters and intermediate results of an algorithm aids the development and evaluation of experimental systems. The modular approach also facilitates extension of existing systems by the integration of novel methods. DART, the distributed Asynchronous Recognition Toolbox architecture, realises these features. DART has been successfully used for recognition of handwriting and poor quality facsimiles.
Recent advances in distributed object and Internet technologies have made it attractive for organizations to distribute application functions. Typical projects include: the re-hosting of legacy applications that move ...
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Recent advances in distributed object and Internet technologies have made it attractive for organizations to distribute application functions. Typical projects include: the re-hosting of legacy applications that move application functionality to or from mainframe/server environments, the creation of new target independent interfaces for legacy systems, and the development of new applications altogether. Design concerns for such systems include security, reliability, and performance. The performance of these systems often defy intuition and must be taken into account during their design. In this paper we present a performance engineering tool for developing predictive models for such systems. The tool automates model construction by developing the structure of the model and measuring parameters that are difficult to estimate or capture manually. Designers can then focus on the performance impact of system configuration alternatives. We show how these results have been integrated into a prototype of IBM's distributed Application Development Toolkit (DADT). A case study is presented that considers the hosting of sample application across three architectural models: Client/Server using DCE, Web Server/Server using HTML/HTTP/CGI, and a JAVA/CORBA-ORB/ Server model.
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