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Symposium on Applied computing

作者： J.D.F. Cosgrove J.C. Diaz Mathematics and Computer Science Cameron University Center for Parallel and Scientific Computing University of Tulsa

Graph-theoretical properties of an adaptive fill-in strategy for the construction of sparse approximate inverses of sparse matrices are discussed. The approximate inverse is based on minimization of the Frobenius norm and lends itself naturally to a parallel implementation. General sparsity can be exploited in a straightforward fashion. Sparse-graph algorithms for the location of fill-in within each column of the approximate inverse preconditioning are described using level sets. Examples illustrating the approach are presented. Properties of the fill-in strategy for regularly structured sparsity patterns are established.< >

关键词： Least squares approximation Sparse matrices Least squares methods Level set Parallel processing Mathematics computer science Iterative methods scientific computing Bipartite graph

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A Service Oriented Approach for Distributed Data Mediation on the Grid

A Service Oriented Approach for Distributed Data Mediation o...

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International Conference on Grid and Cooperative computing (GCC)

作者： Martin Koehler Siegfried Benkner Department of Scientific Computing Faculty of Computer Science University of Technology Vienna Vienna Austria

Seamless integrated access to data stored in globally distributed databases has become a major challenge in many scientific disciplines. In this paper, we describe a grid-based service-oriented infrastructure that tackles this challenge through the provisioning of virtual data sources realized by means of distributed data mediation services. Virtual data sources offer to the user a single integrated view of distributed heterogeneous databases and information sources while hiding the details of data location, data formats, and access mechanisms of the underlying physical data sources. Personalized views of data sources, tailor-made for specific usage scenarios, may be offered by different virtual data sources. virtual data sources rely on flexible mediation techniques and utilize distributed query processing to optimize complex data integration scenarios. Distributed data mediation services have been realized on top of standard grid and Web services technologies including OGSA-DAI and OGSA-DQP. The generic data service infrastructure described in this paper is being utilized in the context of the European @neurIST project, which develops an advanced service-oriented grid infrastructure for the management and treatment of multi-factorial diseases. Details of distributed data mediation and query processing are presented in the context of an experimental scenario integrating clinical data bases.

关键词： Mediation Distributed computing Grid computing Diseases scientific computing computer science Distributed databases Query processing Web services Project management

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Accessing and steering the elastic OLAP cloud

Accessing and steering the elastic OLAP cloud

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Proceedings of the International Convention MIPRO

作者： Sicen Ye Peng Chen Ivan Janciak Peter Brezany Research Group of Scientific Computing Faculty of Computer Science University of Vienna Vienna Austria

A typical cloud platform provides capability of scalability, elasticity and fault tolerance. Moreover, it is designed to deal with high volumes of data on nearly unlimited number of machines. On-Line Analytical Processing (OLAP), a kernel part of modern decision support systems, allows interactive analysis of multidimensional data of varied granularity. A combination of the Cloud computing and OLAP technologies brings challenges in providing OLAP analysis services in distributed environments. This paper first presents an overview of our on-going research of Elastic OLAP Cloud Platform. Then it introduces our design and implementation of a multi-tier client system, which on one hand interacts with the Elastic OLAP Cloud platform, provides Web based Graphical User Interfaces for administration of virtual OLAP cubes and performing OLAP analysis queries, and on the other hand, interacts with the OGSA-DAI middleware to access heterogeneous data sources and load integrated data into the Elastic OLAP Cloud platform. The communication between the client and the platform is based on our home-grown OLAP Modeling Markup Language (OMML), which is also presented in this paper.

关键词： Servers XML Cloud computing Graphical user interfaces Distributed databases computer architecture

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Approximation and competitive algorithms for single-minded selling problem 1

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12th International Conference on Algorithmic Aspects in Information and Management, AAIM 2018

作者： Chin, Francis Y. L. Poon, Sheung-Hung Ting, Hing-Fung Xu, Dachuan Yu, Dongxiao Zhang, Yong Department of Computer Science The University of Hong Kong Pok Fu Lam Hong Kong School of Computer Science University of Nottingham Ningbo China Ningbo China Beijing Institute for Scientific and Engineering Computing Beijing University of Technology Beijing China Institute of Intelligent Computing School of Computer Science and Technology Shandong University Qingdao266237 China Research Center for High Performance Computing Joint Engineering Research Center for Health Big Data Intelligent Analysis Technology Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China

ISBN: (数字)9783030046187

ISBN: (纸本)9783030046170

The problem of item selling with the objective of maximizing the revenue is studied. Given a seller with k types of items and n single-minded buyers, i.e., each buyer is only interested in a particular bundle of items, to maximize the revenue, the seller must carefully assign some amount of bundles to each buyer with respect to the buyer’s accepted price. Each buyer bi is associated with a value function vi(·) such that vi(x) is the accepted unit bundle price bi is willing to pay for x bundles. We show that the single-minded item selling problem is NP-hard. Moreover, we give an O(√k)-approximation algorithm. For the online version, i.e., the buyers come one by one and the decision on each buyer must be made before the arrival of the next buyer, an O(√k · (log h + log k))- competitive algorithm is achieved, where h is the highest unit item price among all buyers. © Springer Nature Switzerland AG 2018.

关键词： Sales

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A Service-Oriented Grid Environment with On-demand QoS Support

A Service-Oriented Grid Environment with On-demand QoS Suppo...

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IEEE World Congress on Services (SERVICES)

作者： Gerhard Engelbrecht Siegfried Benkner Institute of Scientific Computing Faculty of Computer Science University of Technology Vienna Vienna Austria

The evolution of Grid computing technologies over recent years has been dominated by the adoption of a service-oriented paradigm and an increasing use of commercial Web services technologies. Closely linked to this transition are QoS mechanisms such as service level agreements. The work presented in this paper contributes to this evolution by proposing a service-oriented Grid infrastructure with on-demand Quality of Service support. The presented infrastructure is based on standard Web services technologies and enables the provision of compute intensive HPC applications as services in an automated way. The system employs a business-oriented model for Grid computing incorporating dynamic negotiation of service level agreements. The underlying QoS support relies on advance resource-reservation, application-specific resource requirement estimation and according dynamic resource pricing.

关键词： Quality of service Web services Grid computing computer applications Pricing Service oriented architecture Application software scientific computing computer science computer architecture

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Preserving time in large-scale communication traces

Preserving time in large-scale communication traces

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22nd ACM International Conference on Supercomputing, ICS'08

作者： Ratn, Prasun Mueller, Frank De Supinski, Bronis R. Schulz, Martin North Carolina State University Department of Computer Science Raleigh NC 27695-7534 United States Lawrence Livermore National Laboratory Center for Applied Scientific Computing Livermore CA 94551 United States

ISBN: (纸本)9781605581583

Analyzing the performance of large-scale scientific applications is becoming increasingly difficult due to the sheer size of performance data gathered. Recent work on scalable communication tracing applies online interprocess compression to address this problem. Yet, analysis of communication traces requires knowledge about time progression that cannot trivially be encoded in a scalable manner during compression. We develop scalable time stamp encoding schemes for communication traces. At the same time, our work contributes novel insights into the scalable representation of time stamped data. We show that our representations capture sufficient information to enable what-if explorations of architectural variations and analysis for path-based timing irregularities while not requiring excessive disk space. We evaluate the ability of several time-stamped compressed MPI trace approaches to enable accurate timed replay of communication events. Our lossless traces are orders of magnitude smaller, if not near constant size, regardless of the number of nodes while preserving timing information suitable for application tuning or assessing requirements of future procurements. Our results prove timepreserving tracing without loss of communication information can scale in the number of nodes and time steps, which is a result without precedent. Copyright 2008 Association for computing Machinery.

关键词： Message passing

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A (Radical) Proposal Addressing the Non-scalability of the Irregular MPI Collective Interfaces

A (Radical) Proposal Addressing the Non-scalability of the I...

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IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum (IPDPSW)

作者： Jesper Larsson Traff Department of Scientific Computing Faculty of Computer Science University of Technology Vienna Vienna Austria

In both the regular and the irregular MPI collectives there is a correspondence between the argument lists and certain MPI derived datatypes. As a means to address and alleviate well-known memory and performance scalability problems in the irregular (or vector) collective interface definitions of MPI we propose to push this correspondence to its natural limit, and replace the interfaces of the MPI collectives with a new set of interfaces that specify all data sizes and displacements solely by means of derived datatypes. This reduces the number of collective (communication and reduction) interfaces from 16 to 10 (in the extreme to only 7), significantly generalizes the operations, unifies regular and irregular collective interfaces, makes it possible to decouple certain algorithmic decisions from the collective operation, and moves the interface scalability issue from the collective interfaces to the MPI derived datatypes. To complete the proposal we discuss the memory scalability of the derived datatypes and suggest a number of new datatypes for MPI, some of which may be of independent interest. Finally, we introduce additional, new functionality for scalable construction of datatypes as needed for the new collective interfaces. We give examples throughout of the benefits of this alternative set of collective interfaces. It is argued that an implementation can straightforwardly be undertaken within any reasonable MPI implementation.

关键词： Scalability Proposals Layout Tiles Indexes Semantics Limiting

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Intelligent diabetes management

Intelligent diabetes management

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2001 ASEE Annual Conference and Exposition: Peppers, Papers, Pueblos and Professors

作者： Garcia, Mario A. Steidley, Carl Dantu, Maruthi Shen, Rui Texas A and M Univ. Corpus Christi Department of Computer Science Department of Computing Sciences NASA Ames Research Center Oak Ridge Natl. Labs. Electro Scientific Industries Portland

Diabetes is a disease that affects many people in the world1. Diabetes cost in the U.S.A. is estimated to represent 5.8% of total personal health-care expenditures. In Europe diabetes is estimated to consume about 10% of the total health care budget. An Intelligent Diabetes Management System was developed by computer science students at Texas A&M University Corpus Christi to help people monitor and control the blood glucose level. The diabetes experts were Dr. Steve Ponder and Dr. Hilda Ramirez from Driscoll Children's Hospital. This paper describes the steps followed to implement it.

关键词： Intelligent agents

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Dynamic load balancing in parallel finite element simulations 7th

Dynamic load balancing in parallel finite element simulation...

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7th International Conference on High-Performance computing and Networking, HPCN Europe 1999

作者： Schoneveld, Arjen Lees, Martin Karyadi, Erwan Sloot, Peter M. A. Parallel Scientific Computing and Simulation Group Computer Science Physics and Astronomy University of Amsterdam Kruislaan 403 SJ Amsterdam1098 Netherlands The MacNeal-Schwendler Corporation Groningenweg 6 PV Gouda2803 Netherlands

ISBN: (纸本)3540658211

In this paper we introduce a new method for parallelizing Finite Element simulations enabling the use of dynamic load balancing. A physical space partitioning is obtained by dividing the bounding cube into a large number of sub cubes. The cube mesh together with a workload attribute assigned to each cube is used to present an abstract view of the simulation. Based on this abstract view a dynamic load balancing process decides on a possible local repartitioning of the mesh. The dynamic load balancing process itself is diffusion based, that is cubes are migrated between neighboring partitions. A parallel simulation framework (P-CAM) is used to implement the dynamic load balancer. © Springer-Verlag Berlin Heidelberg 1999.

关键词： Dynamic loads

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Regularized two-stage submodular maximization under streaming

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science China(Information sciences) 2022年第4期65卷 102-111页

作者： Ruiqi YANG Dachuan XU Longkun GUO Dongmei ZHANG Beijing Institute for Scientific and Engineering Computing Beijing University of Technology School of Mathematical Sciences University of Chinese Academy Sciences School of Computer Science and Technology Qilu University of Technology School of Computer Science and Technology Shandong Jianzhu University

In the problem of maximizing regularized two-stage submodular functions in streams, we assemble a family ■ of m functions each of which is submodular and is visited in a streaming style that an element is visited for only once. The aim is to choose a subset S of size at most ■ from the element stream ■, so as to maximize the average maximum value of these functions restricted on S with a regularized modular term. The problem can be formally cast as ■, where c:■ is a non-negative modular function and ■ is a non-negative monotone non-decreasing submodular function. The well-studied regularized problem of ■ is exactly a special case of the above regularized two-stage submodular maximization by setting m=1 and ■=k. Although f(·)-c(·) is submodular, it is potentially negative and non-monotone and admits no constant multiplicative factor approximation. Therefore, we adopt a slightly weaker notion of approximation which constructs S such that f(S)-c(S)≥ρ·f(O)-c(O) holds against optimum solution O for some ρ∈(0, 1). Eventually, we devise a streaming algorithm by employing the distorted threshold technique, achieving a weaker approximation ratio with ρ=0.2996 for the discussed regularized two-stage model.

关键词： submodular maximization streaming model two-stage threshold technique approximation algorithms

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