Most viewed papers

641. Gankevich I.G., Balyan S.G., Abrahamyan S.A., Korkhov V.V.
     Applications of on-demand virtual clusters to high performance computing
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 511-516

     Virtual machines are usually associated with an ability to create them on demand by calling web services, then these machines are used to deliver resident services to their clients; however, providing clients with an ability to run an arbitrary programme on the newly created machines is beyond their power. Such kind of usage is useful in a high performance computing environment where most of the resources are consumed by batch programmes and not by daemons or services. In this case a cluster of virtual machines is created on demand to run a distributed or parallel programme and to save its output to a network attached storage. Upon completion this cluster is destroyed and resources are released. With certain modifications this approach can be extended to interactively deliver computational resources to the user thus providing virtual desktop as a service. Experiments show that the process of creating virtual clusters on demand can be made efficient in both cases.

     Keywords: virtual machine, lightweight virtualisation, application containers.
     Views (last year): 1.
642. Iakushkin O.O., Degtyarev A.B., Shvemberger S.V.
     Decomposition of the modeling task of some objects of archeological research for processing in a distributed computer system
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 533-537

     Although each task of recreating artifacts is truly unique, the modeling process for façades, foundations and building elements can be parametrized. This paper is focused on a complex of the existing programming libraries and solutions that need to be united into a single computer system to solve such a task. An algorithm of generating 3D filling of objects under reconstruction is presented. The solution architecture necessary for the system's adaptation for a cloud environment is studied.

     Keywords: distributed systems, cloud computing, modeling, reconstructions, service application architecture.
     Views (last year): 1. Citations: 2 (RSCI).
643. Kiryanov A.K.
     GridFTP frontend with redirection for DMlite
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 543-547

     One of the most widely used storage solutions in WLCG is a Disk Pool Manager (DPM) developed and supported by SDC/ID group at CERN. Recently DPM went through a massive overhaul to address scalability and extensibility issues of the old code.

     New system was called DMLite. Unlike the old DPM that was based on daemons, DMLite is arranged as a library that can be loaded directly by an application. This approach greatly improves performance and transaction rate by avoiding unnecessary inter-process communication via network as well as threading bottlenecks.

     DMLite has a modular architecture with its core library providing only the very basic functionality. Backends (storage engines) and frontends (data access protocols) are implemented as plug-in modules. Doubtlessly DMLite wouldn't be able to completely replace DPM without GridFTP as it is used for most of the data transfers in WLCG.

     In DPM GridFTP support was implemented in a Data Storage Interface (DSI) module for Globus’ GridFTP server. In DMLite an effort was made to rewrite a GridFTP module from scratch in order to take advantage of new DMLite features and also implement new functionality. The most important improvement over the old version is a redirection capability.

     With old GridFTP frontend a client needed to contact SRM on the head node in order to obtain a transfer URL (TURL) before reading or writing a file. With new GridFTP frontend this is no longer necessary: a client may connect directly to the GridFTP server on the head node and perform file I/O using only logical file names (LFNs). Data channel is then automatically redirected to a proper disk node.

     This renders the most often used part of SRM unnecessary, simplifies file access and improves performance. It also makes DMLite a more appealing choice for non-LHC VOs that were never much interested in SRM.

     With new GridFTP frontend it's also possible to access data on various DMLite-supported backends like HDFS, S3 and legacy DPM.

     Keywords: WLCG, Grid, GridFTP, DPM, DMLite, data storage, access protocol.
     Views (last year): 1.
644. Reed R.G., Cox M.A., Wrigley T., Mellado B.
     A CPU benchmarking characterization of ARM based processors
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 581-586

     Big science projects are producing data at ever increases rates. Typical techniques involve storing the data to disk, after minor filtering, and then processing it in large computer farms. Data production has reached a point where on-line processing is required in order to filter the data down to manageable sizes. A potential solution involves using low-cost, low-power ARM processors in large arrays to provide massive parallelisation for data stream computing (DSC). The main advantage in using System on Chips (SoCs) is inherent in its design philosophy. SoCs are primarily used in mobile devices and hence consume less power while maintaining relatively good performance. A benchmarking characterisation of three different models of ARM processors will be presented.

     Keywords: High data throughput, Computing, Big Data, ARM System on Chips, Benchmarking.
     Views (last year): 1.
645. Bogdanov A.V., Thurein Kyaw L.
     Query optimization in relational database systems and cloud computing technology
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 649-655

     Optimization is the heart of relational Database Management System (DMBS). Its can analyzes the SQL statements and determines the most efficient access plan to satisfy every query request. Optimization can solves this problem and analyzes SQL statements specifying which tables and columns are available. And then request the information system and statistical data stored in the system directory, to determine the best method of solving the tasks required to comply with the query requests.

     Keywords: query optimization, cloud computing technology, relational database systems.
     Views (last year): 1.
646. Zhuravlev E.E., Ivanov S.V., Kamenshchikov A.A., Kornienko V.N., Oleynikov A.Ya., Shirobokova T.D.
     Aspects of methodology of ensuring interoperability in the Gridenvironment and cloud computing
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 675-682

     The technique of ensuring of interoperability for Grid-systems and systems of cloud computing is provided. The technique is constructed on a basis of the uniform approach of ensuring interoperability for systems of the wide class offered by authors and recorded in the national Russian Federation standard.

     Keywords: interoperability, grid, grid-environment, cloud computing, clouds, methodology, standardization.
     Views (last year): 1. Citations: 3 (RSCI).
647. Lemtyuzhnikova D.V.
     Parallel representation of local elimination algorithm for accelerating the solving sparse discrete optimization problems
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 699-705

     The decomposition algorithms provide approaches to deal with NP-hardness in solving discrete optimization problems (DOPs). In this article one of the promising ways to exploit sparse matrices — local elimination algorithm in parallel interpretation (LEAP) are demonstrated. That is a graph-based structural decomposition algorithm, which allows to compute a solution in stages such that each of them uses results from previous stages. At the same time LEAP heavily depends on elimination ordering which actually provides solving stages. Also paper considers tree- and block-parallel for LEAP and required realization process of it comparison of a several heuristics for obtaining a better elimination order and shows how is related graph structure, elimination ordering and solving time.

     Keywords: discrete optimization, volunteer computing, local elimination algorithm, parallel computing, sparse problems, elimination tree.
     Views (last year): 1.
648. Oleynikov B.V., Shalabay A.I.
     Crowd funding in the construction of distributed grid-system of electronic library and internet resources
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 715-718

     In the design of a distributed library system, there are a lot of organizational problems, ideas, solutions which are the subject of this article. The article presents the approaches on crowd funding platforms that are used as a tool for attracting participants and financing project.

     Keywords: distributed library system, crowd funding, attracting participants.
     Views (last year): 1.
649. Shefov K.S., Stepanova M.M.
     An implementation of a parallel global minimum search algorithm with an application to the ReaxFF molecular dynamic force field parameters optimization
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 745-752

     Molecular dynamic methods that use ReaxFF force field allow one to obtain sufficiently good results in simulating large multicomponent chemically reactive systems. Here is represented an algorithm of searching optimal parameters of molecular-dynamic force field ReaxFF for arbitrary chemical systems and its implementation. The method is based on the multidimensional technique of global minimum search suggested by R.G. Strongin. It has good scalability useful for running on distributed parallel computers.

     Keywords: numerical simulation, molecular dynamics, reactive force field, chemically reactive systems, parameter optimization, parallel algorithm, absolute extremum search.
     Views (last year): 1. Citations: 1 (RSCI).
650. Degtyarev A.B., Yezhakova T.R., Khramushin V.N.
     Algorithmic construction of explicit numerical schemes and visualization of objects and processes in the computational experiment in fluid mechanics
     Computer Research and Modeling, 2015, v. 7, no. 3, pp. 767-774

     The paper discusses the design and verification stages in the development of complex numerical algorithms to create direct computational experiments in fluid mechanics. The modeling of physical fields and nonstationary processes of continuum mechanics, it is desirable to rely on strict rules of construction the numerical objects and related computational algorithms. Synthesis of adaptive the numerical objects and effective arithmetic- logic operations can serve to optimize the whole computing tasks, provided strict following and compliance with the original of the laws of fluid mechanics. The possibility of using ternary logic enables to resolve some contradictions of functional and declarative programming in the implementation of purely applied problems of mechanics. Similar design decisions lead to new numerical schemes tensor mathematics to help optimize effectiveness and validate correctness the simulation results. The most important consequence is the possibility of using interactive graphical techniques for the visualization of intermediate results of modeling, as well as managed to influence the course of computing experiment under the supervision of engineers aerohydrodynamics– researchers.

     Keywords: tensor mathematics, large particles, fluidmechanics, computational experiment, design, verifying Citation:.
     Views (last year): 1.

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