Journal articles: 'Computational grids'

1

Fox, F., and D. Gannon. "Computational grids." Computing in Science & Engineering 3, no. 4 (2001): 74–77. http://dx.doi.org/10.1109/5992.931906.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

MacKinnon, Bryan. "Commercial computational grids." Ubiquity 2003, May (May 2003): 1. http://dx.doi.org/10.1145/782792.782793.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Pardhanani, Anand, and Graham F. Carey. "Optimization of computational grids." Numerical Methods for Partial Differential Equations 4, no. 2 (1988): 95–117. http://dx.doi.org/10.1002/num.1690040202.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Nikitina, A. V., A. E. Chistyakov, and A. M. Atayan. "NUMERICAL IMPLEMENTATION OF A PARALLEL ALGORITHM FOR SOLVING THE PROBLEM OF POLLUTANT TRANSPORT IN A RESERVOIR ON A HIGH-PERFORMANCE COMPUTER SYSTEM." Vestnik komp'iuternykh i informatsionnykh tekhnologii, no. 202 (April 2021): 27–36. http://dx.doi.org/10.14489/vkit.2021.04.pp.027-036.

Full text

Abstract:

The purpose of this work is to create a software package for a distributed solution of the problem of transporting a pollutant in a reservoir with complex bathymetry and the presence of technological structures. An algorithm has been developed for the parallel solution of the problem of transporting a pollutant (pollutant) in a reservoir on a graphics accelerator controlled by the CUDA (Compute Unified Device Architecture) system; a comparative analysis of the operation of algorithms on a CPU (Central Processing Unit) and on a graphics accelerator GPU (Graphics Processing Unit) made it possible to evaluate their performance. The software implementation of the modules included in the complex is described, the main classes and implemented methods are documented. The results of numerical experiments showed that solving of pollutant transport’s problem based on the CUDA technology is ineffective for small grids (up to 100 ´ 100 computational nodes). In the case of large grids (1000 ´ 1000 computational nodes), the use of CUDA technology reduces the computation time by an order of magnitude. An analysis of the experiments carried out with the developed components of software showed that the maximum value of the ratio of the algorithm operating time that implements the set task of transferring matter in a shallow water on a GPU to the operating time of a similar algorithm on the CPU was 24.92 times, which is achieved on a grid of 1000 ´ 1000 computational nodes. Implementation of methods for decomposition of grid regions is proposed for solving computationally laborious problems of diffusion-convection, including the problem of transporting pollutants in a reservoir with complex bathymetry with technological objects that take into account the architecture and parameters of a MSC (Multiprocessor Computing System) located on the basis of the infrastructure facility of the STU (Scientific and Technological University) “Sirius” (Sochi, Russia). Consideration was made for such a property of a computing system as the time it takes to transmit and receive floating point data. An algorithm for the parallel solution of the task under the control of MPI (Message Passing Interface) technology has been developed, and its efficiency has been assessed. The acceleration values of the proposed algorithm are obtained depending on the number of involved computers (processors) and the size of the computational grid. The maximum number of computers used is 24, the maximum size of the computational grid was 10 000 ´ 10 000 computational nodes. The developed algorithm showed low efficiency for small computational grids (up to 100 ´ 100 computational nodes). In the case of large computational grids ( from 1000  1000 computational nodes), the use of MPI reduces the computation time by several times.

APA, Harvard, Vancouver, ISO, and other styles

5

Zhang, Wensheng, and Hui Zheng. "A multiscale method for wave propagation in 3D heterogeneous poroelastic media." GEOPHYSICS 84, no. 4 (July 1, 2019): T237—T257. http://dx.doi.org/10.1190/geo2018-0482.1.

Full text

Abstract:

A new multiscale method for wave simulation in 3D heterogeneous poroelastic media is developed. Wave propagation in inhomogeneous media involves many different scales of media. The physical parameters in the real media usually vary greatly within a very small scale. For the direct numerical methods for wave simulation, a refined grid is required in mesh generation to maintain the match between the mesh size and the material variations in the spatial scale. This greatly increases the computational cost and computer memory requirements. The multiscale method can overcome this difficulty due to the scale difference. The basic idea of our multiscale method is to construct computational schemes on two sets of meshes, i.e., coarse grids and fine grids. The finite-volume method is applied on the coarse grids, whereas the multiscale basis functions are computed with the finite-element method by solving a local problem on the fine grids. Moreover, the local problem only needs to be solved once before time stepping. This allows us to use a coarse grid while still capturing the information of the physical property variations in the small scale. Therefore, it has better accuracy than the single-scale method when they use the same coarse grids. The theoretical method and the dispersion analysis are investigated. Numerical computations with the perfectly matched layer boundary conditions are completed for 3D inhomogeneous poroelastic models with randomly distributed small scatterers. The results indicate that our multiscale method can effectively simulate wave propagation in 3D heterogeneous poroelastic media with a significant reduction in computation cost.

APA, Harvard, Vancouver, ISO, and other styles

6

Yadav, Monika. "Energy Conservation In Computational Grids." International Journal of Grid Computing & Applications 3, no. 2 (June 30, 2012): 13–18. http://dx.doi.org/10.5121/ijgca.2012.3202.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Jie, Wei, Tianyi Zang, Terence Hung, Stephen J. Turner, and Wentong Cai. "Information Management for Computational Grids." International Journal of Web Services Research 2, no. 3 (July 2005): 69–82. http://dx.doi.org/10.4018/jwsr.2005070103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Weller, Hilary, John Thuburn, and Colin J. Cotter. "Computational Modes and Grid Imprinting on Five Quasi-Uniform Spherical C Grids." Monthly Weather Review 140, no. 8 (August 1, 2012): 2734–55. http://dx.doi.org/10.1175/mwr-d-11-00193.1.

Full text

Abstract:

Abstract Currently, most operational forecasting models use latitude–longitude grids, whose convergence of meridians toward the poles limits parallel scaling. Quasi-uniform grids might avoid this limitation. Thuburn et al. and Ringler et al. have developed a method for arbitrarily structured, orthogonal C grids called TRiSK, which has many of the desirable properties of the C grid on latitude–longitude grids but which works on a variety of quasi-uniform grids. Here, five quasi-uniform, orthogonal grids of the sphere are investigated using TRiSK to solve the shallow-water equations. Some of the advantages and disadvantages of the hexagonal and triangular icosahedra, a “Voronoi-ized” cubed sphere, a Voronoi-ized skipped latitude–longitude grid, and a grid of kites in comparison to a full latitude–longitude grid are demonstrated. It is shown that the hexagonal icosahedron gives the most accurate results (for least computational cost). All of the grids suffer from spurious computational modes; this is especially true of the kite grid, despite it having exactly twice as many velocity degrees of freedom as height degrees of freedom. However, the computational modes are easiest to control on the hexagonal icosahedron since they consist of vorticity oscillations on the dual grid that can be controlled using a diffusive advection scheme for potential vorticity.

APA, Harvard, Vancouver, ISO, and other styles

9

Chetty, M., and R. Buyya. "Weaving computational grids: how analogous are they with electrical grids?" Computing in Science & Engineering 4, no. 4 (July 2002): 61–71. http://dx.doi.org/10.1109/mcise.2002.1014981.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Carcaillet, Richard, Stephen R. Kennon, and George S. Dulikravich. "Optimization of three-dimensional computational grids." Journal of Aircraft 23, no. 5 (May 1986): 415–21. http://dx.doi.org/10.2514/3.45323.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Kennon, Stephen R., and George S. Dulikravich. "Generation of computational grids using optimization." AIAA Journal 24, no. 7 (July 1986): 1069–73. http://dx.doi.org/10.2514/3.9393.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

HOLLINGSWORTH, JEFFREY K., ETHAN L. MILLER, and KENNEDY AKALA. "BINARY VERSION MANAGEMENT FOR COMPUTATIONAL GRIDS." Parallel Processing Letters 09, no. 02 (June 1999): 215–25. http://dx.doi.org/10.1142/s0129626499000219.

Full text

Abstract:

Applications are no longer monolithic files, but rather a collection of dynamically linked libraries, images, fonts, etc. For such applications to function correctly, all of the required files must be available and be the correct version. Missing files preclude application execution, and incorrect versions lead to mysterious and frustrating failures. This paper describes a simple scheme to address this problem: Content-Derived Names (CDNs). CDNs use digital signatures to automatically and uniquely name specific versions of files. Because Content-Derived Names are computed using a cryptographically strong hash over the text of a package, this process is safe from spoofing and other attacks based on providing the wrong library. We explain how CDNs ease the management of application distribution for clusters and grids. We also describe a prototype implementation of CDNs for the Tel programming language.

APA, Harvard, Vancouver, ISO, and other styles

13

Swany, Martin, and Rich Wolski. "Building Performance Topologies for Computational Grids." International Journal of High Performance Computing Applications 18, no. 2 (May 2004): 255–65. http://dx.doi.org/10.1177/1094342004038957.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Das, Debashreet, Chitta Ranjan Tripathy, Pradyumna Kumar Tripathy, Manas Ranjan Kabat, and Avinash Sharma. "Optimal Design of Computational Grids Topology." Journal of Computational and Theoretical Nanoscience 16, no. 9 (September 1, 2019): 3754–58. http://dx.doi.org/10.1166/jctn.2019.8245.

Full text

Abstract:

The selection of a proper heterogeneous network contributes to the design of various distributed systems such as grids for making an effective layout. However, the level of accuracy of such networks has not been addressed in the past. Hence, this article suggests a new topology which is more accurate and addresses the scalability problem. The experiments are conducted in Matlab and the suggested layout is generated using Network Simulator 2.3. The suggested layout is found to be more effective compared to the traditional layouts for interlinking the systems.

APA, Harvard, Vancouver, ISO, and other styles

15

Squartini, Stefano, Derong Liu, Francesco Piazza, Dongbin Zhao, and Haibo He. "Computational Energy Management in Smart Grids." Neurocomputing 170 (December 2015): 267–69. http://dx.doi.org/10.1016/j.neucom.2015.05.110.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Talbi, El-Ghazali, and Albert Zomaya. "Grids in bioinformatics and computational biology." Journal of Parallel and Distributed Computing 66, no. 12 (December 2006): 1481. http://dx.doi.org/10.1016/j.jpdc.2006.09.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Rzadca, Krzysztof, and Denis Trystram. "Promoting cooperation in selfish computational grids." European Journal of Operational Research 199, no. 3 (December 2009): 647–57. http://dx.doi.org/10.1016/j.ejor.2007.06.067.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Raza, Zahid, and Deo P. Vidyarthi. "Reliability Based Scheduling Model (RSM) for Computational Grids." International Journal of Distributed Systems and Technologies 2, no. 2 (April 2011): 20–37. http://dx.doi.org/10.4018/jdst.2011040102.

Full text

Abstract:

Computational Grid attributed with distributed load sharing has evolved as a platform to large scale problem solving. Grid is a collection of heterogeneous resources, offering services of varying natures, in which jobs are submitted to any of the participating nodes. Scheduling these jobs in such a complex and dynamic environment has many challenges. Reliability analysis of the grid gains paramount importance because grid involves a large number of resources which may fail anytime, making it unreliable. These failures result in wastage of both computational power and money on the scarce grid resources. It is normally desired that the job should be scheduled in an environment that ensures maximum reliability to the job execution. This work presents a reliability based scheduling model for the jobs on the computational grid. The model considers the failure rate of both the software and hardware grid constituents like application demanding execution, nodes executing the job, and the network links supporting data exchange between the nodes. Job allocation using the proposed scheme becomes trusted as it schedules the job based on a priori reliability computation.

APA, Harvard, Vancouver, ISO, and other styles

19

Adil Sbaï, M., and N. Amraoui. "Development and application of diagnostic tools for seawater intrusion analysis in highly heterogeneous coastal aquifers." E3S Web of Conferences 54 (2018): 00030. http://dx.doi.org/10.1051/e3sconf/20185400030.

Full text

Abstract:

We developed novel, computationally efficient, methods as effective screening tools to analyze seawater intrusion processes in highly heterogeneous coastal aquifer systems. They enable delineation of pumping wells capture zones and swept zones associated to injection wells for remediation of seawater encroachment. Forward or backward travel times and residence time distributions are robustly simulated and visualized on the computational grid. These steady-state indicators, precomputed at fine grids, are used to generate optimal locally refined grids for efficient transient solute transport simulations.

APA, Harvard, Vancouver, ISO, and other styles

20

Bhardwaj, Dheeraj, and Manish K. Sinha. "GridFS: highly scalable I/O solution for clusters and computational grids." International Journal of Computational Science and Engineering 2, no. 5/6 (2006): 287. http://dx.doi.org/10.1504/ijcse.2006.014771.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Yang, Chao-Tung, Tsu-Fen Han, and Heng-Chuan Kan. "G-BLAST: a Grid-based solution for mpiBLAST on computational Grids." Concurrency and Computation: Practice and Experience 21, no. 2 (February 2009): 225–55. http://dx.doi.org/10.1002/cpe.1346.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Gerolymos, G. A., and I. Vallet. "Robust Implicit Multigrid Reynolds-Stress Model Computation of 3D Turbomachinery Flows." Journal of Fluids Engineering 129, no. 9 (March 31, 2007): 1212–27. http://dx.doi.org/10.1115/1.2754320.

Full text

Abstract:

The purpose of this paper is to present a numerical methodology for the computation of complex 3D turbomachinery flows using advanced multiequation turbulence closures, including full seven-equation Reynolds-stress transport models. The flow equations are discretized on structured multiblock grids, using an upwind biased (O[ΔxH3]MUSCL reconstruction) finite-volume scheme. Time integration uses a local dual-time-stepping implicit procedure, with internal subiterations. Computational efficiency is achieved by a specific approximate factorization of the implicit subiterations, designed to minimize the computational cost of the turbulence transport equations. Convergence is still accelerated using a mean-flow-multigrid full-approximation-scheme method, where multigrid is applied only on the mean-flow variables. Speed-ups of a factor 3 are obtained using three levels of multigrid (fine plus two coarser grids). Computational examples are presented using two Reynolds-stress models, and also a baseline k−ε model, for various turbomachinery configurations, and compared to available experimental measurements.

APA, Harvard, Vancouver, ISO, and other styles

23

Bernth, Henrik, and Chris Chapman. "A comparison of the dispersion relations for anisotropic elastodynamic finite-difference grids." GEOPHYSICS 76, no. 3 (May 2011): WA43—WA50. http://dx.doi.org/10.1190/1.3555530.

Full text

Abstract:

Several staggered grid schemes have been suggested for performing finite-difference calculations for the elastic wave equations. In this paper, the dispersion relationships and related computational requirements for the Lebedev and rotated staggered grids for anisotropic, elastic, finite-difference calculations in smooth models are analyzed and compared. These grids are related to a popular staggered grid for the isotropic problem, the Virieux grid. The Lebedev grid decomposes into Virieux grids, two in two dimensions and four in three dimensions, which decouple in isotropic media. Therefore the Lebedev scheme will have twice or four times the computational requirements, memory, and CPU as the Virieux grid but can be used with general anisotropy. In two dimensions, the rotated staggered grid is exactly equivalent to the Lebedev grid, but in three dimensions it is fundamentally different. The numerical dispersion in finite-difference grids depends on the direction of propagation and the grid type and parameters. A joint numerical dispersion relation for the two grids types in the isotropic case is derived. In order to compare the computational requirements for the two grid types, the dispersion, averaged over propagation direction and medium velocity are calculated. Setting the parameters so the average dispersion is equal for the two grids, the computational requirements of the two grid types are compared. In three dimensions, the rotated staggered grid requires at least 20% more memory for the field data and at least twice as many number of floating point operations and memory accesses, so the Lebedev grid is more efficient and is to be preferred.

APA, Harvard, Vancouver, ISO, and other styles

24

Kim, Boram, Kwang Seok Yoon, and Hyung-Jun Kim. "GPU-Accelerated Laplace Equation Model Development Based on CUDA Fortran." Water 13, no. 23 (December 4, 2021): 3435. http://dx.doi.org/10.3390/w13233435.

Full text

Abstract:

In this study, a CUDA Fortran-based GPU-accelerated Laplace equation model was developed and applied to several cases. The Laplace equation is one of the equations that can physically analyze the groundwater flows, and is an equation that can provide analytical solutions. Such a numerical model requires a large amount of data to physically regenerate the flow with high accuracy, and requires computational time. These numerical models require a large amount of data to physically reproduce the flow with high accuracy and require computational time. As a way to shorten the computation time by applying CUDA technology, large-scale parallel computations were performed on the GPU, and a program was written to reduce the number of data transfers between the CPU and GPU. A GPU consists of many ALUs specialized in graphic processing, and can perform more concurrent computations than a CPU using multiple ALUs. The computation results of the GPU-accelerated model were compared with the analytical solution of the Laplace equation to verify the accuracy. The computation results of the GPU-accelerated Laplace equation model were in good agreement with the analytical solution. As the number of grids increased, the computational time of the GPU-accelerated model gradually reduced compared to the computational time of the CPU-based Laplace equation model. As a result, the computational time of the GPU-accelerated Laplace equation model was reduced by up to about 50 times.

APA, Harvard, Vancouver, ISO, and other styles

25

Das, Debashreet, Rashmita Pradhan, and Tripathy C.R. "Optimization of Resource Allocation in Computational Grids." International Journal of Grid Computing & Applications 6, no. 1/2 (June 30, 2015): 37–54. http://dx.doi.org/10.5121/ijgca.2015.6204.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Pala, Massimiliano, Shreyas Cholia, Scott A. Rea, and Sean W. Smith. "Interoperable PKI Data Distribution in Computational Grids." International Journal of Grid and High Performance Computing 1, no. 2 (April 2009): 56–73. http://dx.doi.org/10.4018/jghpc.2009040105.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Ding, Li Li, Zheng Wei Wang, and Xiao Ling Wang. "Auction-Based Resource Allocation in Computational Grids." Advanced Materials Research 816-817 (September 2013): 847–50. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.847.

Full text

Abstract:

Auction techniques have been becoming the key methods in grid resource allocation. In this paper, we propose the multi-attribute reverse auction models for computational grid resource based on the designed satisfaction degree function. The fairness is also introduced into the models and protocols to match the reality. Two auction-based protocols are presented, i.e., the offline multi-attribute auction-based protocol and the on-line multi-attribute auction-based protocol. The goal is to help the resource user make multi-attribute decisions with complete information or incomplete information. Results from simulation experiments show that these two protocols can achieve market efficiency and fairness in most instances.

APA, Harvard, Vancouver, ISO, and other styles

28

Derbal, Youcef. "A probabilistic scheduling heuristic for computational grids." Multiagent and Grid Systems 2, no. 1 (May 24, 2006): 45–59. http://dx.doi.org/10.3233/mgs-2006-2104.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Dongarra, Jack J., and Bernard Tourancheau. "Clusters and Computational Grids for Scientific Computing." International Journal of High Performance Computing Applications 13, no. 3 (August 1999): 179. http://dx.doi.org/10.1177/109434209901300301.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Dongarra, Jack, Masaaki Shimasaki, and Bernard Tourancheau. "Clusters and computational grids for scientific computing." Parallel Computing 27, no. 11 (October 2001): 1401–2. http://dx.doi.org/10.1016/s0167-8191(01)00095-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Huang, Sili, Eric Aubanel, and Virendrakumar C. Bhavsar. "PaGrid: A Mesh Partitioner for Computational Grids." Journal of Grid Computing 4, no. 1 (February 1, 2006): 71–88. http://dx.doi.org/10.1007/s10723-005-9018-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

FOX-RABINOVICH, M. S. "On Some Computational Properties of Irregular Grids." Annals of the New York Academy of Sciences 452, no. 1 (October 1985): 395. http://dx.doi.org/10.1111/j.1749-6632.1985.tb30025.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

TANIMURA, Yusuke, Tomoyuki HIROYASU, and Mitsunori Miki. "2206 Genetic Algorithms on the Computational Grids." Proceedings of Design & Systems Conference 2001.11 (2001): 126–29. http://dx.doi.org/10.1299/jsmedsd.2001.11.126.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Fölling, Alexander, and Joachim Lepping. "Knowledge discovery for scheduling in computational grids." Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery 2, no. 4 (June 22, 2012): 287–97. http://dx.doi.org/10.1002/widm.1060.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Surcel, Dorina, and René Laprise. "A General Filter for Stretched-Grid Models: Application in Two-Dimension Polar Geometry." Monthly Weather Review 140, no. 3 (February 1, 2012): 919–40. http://dx.doi.org/10.1175/mwr-d-11-00058.1.

Full text

Abstract:

Abstract Variable-resolution grids are used in global atmospheric models to improve the representation of regional scales over an area of interest: they have reduced computational cost compared to uniform high-resolution grids, and avoid the nesting issues of limited-area models. To address some concerns associated with the stretching and anisotropy of the variable-resolution computational grid, a general convolution filter operator was developed. The convolution filter that was initially applied in Cartesian geometry in a companion paper is here adapted to cylindrical polar coordinates as an intermediate step toward spherical polar latitude–longitude grids. Both polar grids face the so-called “pole problem” because of the convergence of meridians at the poles. In this work the authors will present some details related to the adaptation of the filter to cylindrical polar coordinates for both uniform as well as stretched grids. The results show that the developed operator is skillful in removing the extraneous fine scales around the pole, with a computational cost smaller than that of common polar filters. The results on a stretched grid for vector and scalar test functions are satisfactory and the filter’s response can be optimized for different types of test function and noise one wishes to remove.

APA, Harvard, Vancouver, ISO, and other styles

36

Wang, Zhihao, Ru Huo, and Shuo Wang. "A Lightweight Certificateless Group Key Agreement Method without Pairing Based on Blockchain for Smart Grid." Future Internet 14, no. 4 (April 14, 2022): 119. http://dx.doi.org/10.3390/fi14040119.

Full text

Abstract:

In smart grids, the access verification of a large number of intelligent gateways and terminal devices has become one of the main concerns to ensure system security. This means that smart grids need a new key management method that is safe and efficient and has a low computational cost. Although a large number of scholars have conducted relevant research, most of these schemes cannot balance the computational overhead and security. Therefore, we propose a lightweight and secure key management method, having a low computational overhead, based on blockchain for smart grids. Firstly, we redesigned the architecture of the smart grid based on blockchain and completed the division of various entities. Furthermore, we designed a pairing-free certification authenticated group key agreement method based on blockchain under the architecture. Finally, we achieved higher security attributes, and lower authentication delay and computational overhead, compared to the traditional schemes, as shown in performance analysis and comparison.

APA, Harvard, Vancouver, ISO, and other styles

37

Sodan, Angela C., Garima Gupta, Lin Han, Lun Liu, and Benjamin Lafreniere. "Time and space adaptation for computational grids with the ATOP-Grid middleware." Future Generation Computer Systems 24, no. 6 (June 2008): 561–81. http://dx.doi.org/10.1016/j.future.2007.08.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Bindle, Liam, Randall V. Martin, Matthew J. Cooper, Elizabeth W. Lundgren, Sebastian D. Eastham, Benjamin M. Auer, Thomas L. Clune, et al. "Grid-stretching capability for the GEOS-Chem 13.0.0 atmospheric chemistry model." Geoscientific Model Development 14, no. 10 (October 6, 2021): 5977–97. http://dx.doi.org/10.5194/gmd-14-5977-2021.

Full text

Abstract:

Abstract. Modeling atmospheric chemistry at fine resolution globally is computationally expensive; the capability to focus on specific geographic regions using a multiscale grid is desirable. Here, we develop, validate, and demonstrate stretched grids in the GEOS-Chem atmospheric chemistry model in its high-performance implementation (GCHP). These multiscale grids are specified at runtime by four parameters that offer users nimble control of the region that is refined and the resolution of the refinement. We validate the stretched-grid simulation versus global cubed-sphere simulations. We demonstrate the operation and flexibility of stretched-grid simulations with two case studies that compare simulated tropospheric NO2 column densities from stretched-grid and cubed-sphere simulations to retrieved column densities from the TROPOspheric Monitoring Instrument (TROPOMI). The first case study uses a stretched grid with a broad refinement covering the contiguous US to produce simulated columns that perform similarly to a C180 (∼ 50 km) cubed-sphere simulation at less than one-ninth the computational expense. The second case study experiments with a large stretch factor for a global stretched-grid simulation with a highly localized refinement with ∼10 km resolution for California. We find that the refinement improves spatial agreement with TROPOMI columns compared to a C90 cubed-sphere simulation of comparable computational demands. Overall, we find that stretched grids in GEOS-Chem are a practical tool for fine-resolution regional- or continental-scale simulations of atmospheric chemistry. Stretched grids are available in GEOS-Chem version 13.0.0.

APA, Harvard, Vancouver, ISO, and other styles

39

Ha, Wansoo, and Changsoo Shin. "Efficient Laplace-domain modeling and inversion using an axis transformation technique." GEOPHYSICS 77, no. 4 (July 1, 2012): R141—R148. http://dx.doi.org/10.1190/geo2011-0424.1.

Full text

Abstract:

We tested an axis-transformation technique for modeling wave propagation in the Laplace domain using a finite-difference method. This technique enables us to use small grids near the surface and large grids at depth. Accordingly, we can reduce the number of grids and attain computational efficiency in modeling and inversion in the Laplace domain. We used a dispersion analysis and comparisons between modeled wavefields obtained on the regular and transformed axes. We demonstrated in a synthetic Laplace-domain inversion technique shows that this method is efficient and yields a result comparable to that of a Laplace-domain inversion using a regular grid. In a synthetic inversion example, the memory usage reduced to less than 33%, and the computation time reduced to 39% of those required for the regular grid case using a logarithmic transformation function.

APA, Harvard, Vancouver, ISO, and other styles

40

Zhai, Feng, Ting Yang, Bing Zhao, and Hao Chen. "Privacy-Preserving Outsourcing Algorithms for Multidimensional Data Encryption in Smart Grids." Sensors 22, no. 12 (June 9, 2022): 4365. http://dx.doi.org/10.3390/s22124365.

Full text

Abstract:

With the development of the Internet of Things, smart grids have become indispensable in our daily life and can provide people with reliable electricity generation, transmission, distribution and control. Therefore, how to design a privacy-preserving data aggregation protocol has been a research hot-spot in smart grid technology. However, these proposed protocols often contain some complex cryptographic operations, which are not suitable for resource-constrained smart meter devices. In this paper, we combine data aggregation and the outsourcing of computations to design two privacy-preserving outsourcing algorithms for the modular exponentiation operations involved in the multi-dimensional data aggregation, which can allow these smart meter devices to delegate complex computation tasks to nearby servers for computing. By utilizing our proposed outsourcing algorithms, the computational overhead of resource-constrained smart meter devices can be greatly reduced in the process of data encryption and aggregation. In addition, the proposed algorithms can protect the input’s privacy of smart meter devices and ensure that the smart meter devices can verify the correctness of results from the server with a very small computational cost. From three aspects, including security, verifiability and efficiency, we give a detailed analysis about our proposed algorithms. Finally, through carrying out some experiments, we prove that our algorithms can improve the efficiency of performing the data encryption and aggregation on the smart meter device side.

APA, Harvard, Vancouver, ISO, and other styles

41

Raithby, G. D., and E. H. Chui. "A Finite-Volume Method for Predicting a Radiant Heat Transfer in Enclosures With Participating Media." Journal of Heat Transfer 112, no. 2 (May 1, 1990): 415–23. http://dx.doi.org/10.1115/1.2910394.

Full text

Abstract:

A new “finite-volume” method is proposed to predict radiant heat transfer in enclosures with participating media. The method can conceptually be applied with the same nonorthogonal computational grids used to compute fluid flow and convective heat transfer. A fairly general version of the method is derived, and details are illustrated by applying it to several simple benchmark problems. Test results indicate that good accuracy is obtained on coarse computational grids, and that solution errors diminish rapidly as the grid is refined.

APA, Harvard, Vancouver, ISO, and other styles

42

Yershov, Serhii V., and Viktor A. Yakovlev. "The Influence of Mesh Resolution on 3D RANS Flow Simulations in Turbomachinery Flow Parts." Journal of Mechanical Engineering 24, no. 1 (March 30, 2021): 13–27. http://dx.doi.org/10.15407/pmach2021.01.013.

Full text

Abstract:

The question of the difference mesh refinement degree influence on the results of calculation of the three-dimensional viscous gas flows in the flow parts of turbomachines using the RANS flow models and second order numerical methods is considered. Calculations of flows for a number of turbine and compressor grids on successively refining grids have been performed. We used H-type grids with approximate orthogonalization of cells in the boundary layer. The calculations were carried out using a CFD solver F with the use of an implicit ENO scheme of the second order, a local time step, and a simplified multigrid algorithm. When calculating the flow on fine grids, the following were used: convergence acceleration tools implemented in the solver; truncation of the computational domain with subsequent distribution of the results based on the symmetry property; the computational domain splitting into parts and computations parallelizing. Comparison of the obtained results is carried out, both in terms of qualitative resolution of the complex structure of three-dimensional flows, and in terms of quantitative assessment of losses. Grid convergence was estimated in two ways. In the first, the characteristic two-dimensional distributions of parameters obtained on different grids were visually compared. The purpose of such comparisons was to evaluate the sufficient degree of solution of both the general structure of the flow in grids and its features, namely, shock waves, contact discontinuities, separation zones, wakes, etc. The second estimation method is based on the grid convergence index (GCI). The GCI calculated from the three-dimensional density field was considered in this paper. It is concluded that for scientific research requiring high accuracy of calculations and detailing of the structure of a three-dimensional flow, very fine difference meshes with the number of cells from 106 to 108 in one blade-to-blade channel are needed, while for engineering calculations, under certain conditions, it is sufficient to use meshes with the number of cells less than 1 million in one blade-to-blade channel.

APA, Harvard, Vancouver, ISO, and other styles

43

Kang, Ning, and Yuan Cao. "Research on Computational Fluid Dynamics with Effect of Grid Quality on the Accuracy of Simulated Results of Two Dimensional Low-Speed Parallel Flow." Applied Mechanics and Materials 685 (October 2014): 232–35. http://dx.doi.org/10.4028/www.scientific.net/amm.685.232.

Full text

Abstract:

In the field of computational fluid dynamics, grid generation costs most of work. The accuracy and reliability of the simulated results depend directly on grid quality. The two dimensional parallel flow with low speed was used to study the effect of grid quality on simulated results. Several conclusions are obtained. The computational error decreases with the increase of domain size in flow direction. Too many grids in flow direction will lead to bigger round-off error, while too few grids will make it harder to catch the correct flow. The increase of grid quantity in the direction perpendicular to flow direction will decrease the computational error, but the effect is not obvious. Increasing the grid quantity in the area near the wall will decrease the computational error.

APA, Harvard, Vancouver, ISO, and other styles

44

Paszyńska, A., M. Paszyński, K. Jopek, M. Woźniak, D. Goik, P. Gurgul, H. AbouEisha, et al. "Quasi-Optimal Elimination Trees for 2D Grids with Singularities." Scientific Programming 2015 (2015): 1–18. http://dx.doi.org/10.1155/2015/303024.

Full text

Abstract:

We construct quasi-optimal elimination trees for 2D finite element meshes with singularities. These trees minimize the complexity of the solution of the discrete system. The computational cost estimates of the elimination process model the execution of the multifrontal algorithms in serial and in parallel shared-memory executions. Since the meshes considered are a subspace of all possible mesh partitions, we call these minimizers quasi-optimal. We minimize the cost functionals using dynamic programming. Finding these minimizers is more computationally expensive than solving the original algebraic system. Nevertheless, from the insights provided by the analysis of the dynamic programming minima, we propose a heuristic construction of the elimination trees that has costONelog⁡Ne, whereNeis the number of elements in the mesh. We show that this heuristic ordering has similar computational cost to the quasi-optimal elimination trees found with dynamic programming and outperforms state-of-the-art alternatives in our numerical experiments.

APA, Harvard, Vancouver, ISO, and other styles

45

Khokhlov, Nikolay I., Alena Favorskaya, and Vladislav Furgailo. "Grid-Characteristic Method on Overlapping Curvilinear Meshes for Modeling Elastic Waves Scattering on Geological Fractures." Minerals 12, no. 12 (December 12, 2022): 1597. http://dx.doi.org/10.3390/min12121597.

Full text

Abstract:

Interest in computational methods for calculating wave scattering from fractured geological clusters is due to their application in processing and interpreting the data obtained during seismic prospecting of hydrocarbon and other mineral deposits. In real calculations, numerical methods on structured, regular (Cartesian) computational grids are used to conserve computational resources though these methods do not correctly model the scattering of elastic waves from fractures that are not co-directed to the coordinate axes. The use of computational methods on other types of grids requires an increase in computational resources, which is unacceptable for the subsequent solution of inverse problems. This article is devoted to a possible solution to this problem. We suggest a novel modification of a computational grid-characteristic method on overlapping curvilinear grids. In the proposed approach, a small overlapping curvilinear grid is placed around a fracture that smoothly merges into the surrounding Cartesian background mesh, which helps to avoid interpolation between the background and overlapping meshes. This work presents the results of testing this method, which showed its high accuracy. The disadvantages of the developed method include the limited types of fractured clusters for which this method can be applied since the overlapping meshes should not intersect. However, clusters of subvertical fractures are usually found in nature; therefore, the developed method is applicable in most cases.

APA, Harvard, Vancouver, ISO, and other styles

46

Marsico, David H., and Samuel N. Stechmann. "Expanding Grids for Efficient Cloud Dynamics Simulations Across Scales." Mathematics of Climate and Weather Forecasting 6, no. 1 (July 30, 2020): 38–49. http://dx.doi.org/10.1515/mcwf-2020-0101.

Full text

Abstract:

AbstractWith large eddy simulations (LES) and/or cloud-resolving models (CRMs), it is now possible to simultaneously simulate shallow and deep convection. However, using traditional methods, the computational expense is typically very large, due to the small grid spacings needed to resolve shallow clouds. Here, the main purpose is to present a method that is computationally less expensive by a factor of roughly 10 to 50. Unlike traditional grid stretching of only the vertical z grid spacing, the present method involves expansion of the grid spacing in all coordinate directions (x,y,z) and time t. A ˝ne grid spacing of O(10)-O(100) m can be used near the surface to resolve boundary layer turbulence, and the grid spacing expands to be O(1000) m at higher altitudes, which reduces computational cost while still resolving deep convection. Example simulations are conducted with a simpli˝ed LES/CRM in 2D to verify the theoretical cost savings.

APA, Harvard, Vancouver, ISO, and other styles

47

Das, Arindam. "On Fault Tolerance of Resources in Computational Grids." International Journal of Grid Computing & Applications 3, no. 3 (September 30, 2012): 1–10. http://dx.doi.org/10.5121/ijgca.2012.3301.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Kumar, A., and H. Pathak. "Fuzzy Min Max Scheduling (FMiMaS) for Computational Grids." International Journal of Computer Sciences and Engineering 6, no. 6 (June 30, 2018): 567–75. http://dx.doi.org/10.26438/ijcse/v6i6.567575.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Ali, Hesham, Alaa E. Abdel-Hakim, and Mohammed Ahmed. "A survey of resource discovery in computational grids." International Conference on Electrical Engineering 8, no. 8 (May 1, 2012): 1–30. http://dx.doi.org/10.21608/iceeng.2012.32712.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

ARNOLD, DORIAN C., SATHISH S. VAHDIYAR, and JACK J. DONGARRA. "ON THE CONVERGENCE OF COMPUTATIONAL AND DATA GRIDS." Parallel Processing Letters 11, no. 02n03 (June 2001): 187–202. http://dx.doi.org/10.1142/s012962640100052x.

Full text

Abstract:

Great advances in high-performance computing have given rise to scientific applications that place large demands on software and hardware infrastructures for both computational and data services. With these trends the necessity has emerged for distributed systems developers that once distinguished between these elements to acknowledge that indeed computational and data services are tightly coupled and need to be addressed simultaneously. In this article, we compile and discuss several strategies and techniques, like co-scheduling and co-allocation of computational and data services, dynamic storage capabilities, and quality-of-service, that can be used to help resolve some of the aforementioned issues. We present our interactions with a distributed computing system, NetSolve, and a Distributed Storage Infrastructure, IBP, as a case study of how some of these techniques can be effectively deployed and offer experimental evidence from early prototypes that validate our motivation and direction.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Computational grids'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles