Numer czasopisma
Computer Science
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ISSN: 1508-2806
e-ISSN:
Data wydania
2015
Rocznik
Vol. 16
Numer
No. 1
Prawa dostępu
Dostęp: otwarty dostęp
Uwagi:
Prawa: CC BY 4.0 
Uznanie autorstwa 4.0 Międzynarodowe (CC BY 4.0)
Strony
Opis
Rocznik czasopisma (rel.)
Rocznik czasopisma
Computer Science
Vol. 16 (2015)
Artykuły numeru (rel.)
Artykuł
Dostęp ograniczony
Model of reconfiguration in component environments
(2015) Grzesiak, Jakub; Jędrychowski, Łukasz
The significance of component-based software and component platforms has increased over the last twenty years. To achieve full flexibility, a reconfiguration process is needed that allows us to change system parameters without rebuilding or restarting. In terms of components, such a process should be executed with extraordinary care, since the contracts between components must be preserved. In this article, a model of reconfiguration (including the roles of the components to be used in this process) is proposed. The provided solution is general and could be applied to many component platforms.
Artykuł
Dostęp ograniczony
Confronting theoretical predictions with experimental data, a fitting strategy for multi-dimensional distributions
(2015) Przedziński, Tomasz; Roig Garcés, Pablo; Šehovcova, Ol'ga; Wąs, Zbigniew; Zaremba, Jakub
After developing a Resonance Chiral Lagrangian (R?L) model to describe hadronic ? lepton decays, the model was confronted with experimental data. This was accomplished by using a fitting framework that was developed to take into account the complexity of the model and to ensure numerical stability for the algorithms used in the fitting. Since the model used in the fit contained 15 parameters and there were only three one-dimensional distributions available, we could expect multiple local minima or even whole regions of equal potential to appear. Our methods had to thoroughly explore the whole parameter space and ensure (as well as possible) that the result is a global minimum. This paper is focused on the technical aspects of the fitting strategy used. The first approach was based on a re-weighting algorithm published in article Shekhovtsova et al. and produced results in about two weeks. A later approach, with an improved theoretical model and a simple parallelization algorithm based on Inter-Process Communication (IPC) methods of UNIX system, reduced computation time down to 2–3 days. Additional approximations were introduced to the model, decreasing the necessary time to obtain the preliminary results down to 8 hours. This allowed us to better validate the results, leading to a more robust analysis published in article Nugent et al.
Artykuł
Dostęp ograniczony
Computational challenges in the measurement of heavy-ion collision event characteristics with the atlas experiment at the LHC
(2015) Burka, Klaudia; Grabowska-Bołd, Iwona; Bołd, Tomasz
Heavy-ion collisions at extreme energies are expected to recreate conditions present in the early universe, producing a state of matter called the Quark Gluon Plasma (QGP). This state is characterized by very low viscosity resembling the properties of a perfect fluid. In such a medium, density fluctuations can easily propagate. In experimental practice, the size of these fluctuations is estimated by measuring the angular correlation of the particles produced. The aim of this paper is to present results of the measurements of the azimuthal anisotropy of charged particles produced in heavy-ion collisions with the ATLAS detector using the LHC Grid infrastructure for bulk processing of the data and resources available at the Tier-2 computing center for the final analysis stage.
Artykuł
Dostęp ograniczony
Distributed Web service repository
(2015) Nawrocki, Piotr; Mamla, Aleksander
The increasing availability and popularity of computer systems has resulted in a demand for new language- and platform-independent ways of data exchange. This demand has, in turn, led to significant growth in the importance of systems based on Web services. Alongside the growing number of systems accessible via Web services came the need for specialized data repositories that could offer effective means of searching the available services. The development of mobile systems and wireless data transmission technologies has allowed us to use distributed devices and computer systems on a greater scale. The accelerating growth of distributed systems might be a good reason to consider the development of distributed Web service repositories with built-in mechanisms for data migration and synchronization.
Artykuł
Dostęp ograniczony
Hypergrammar-based parallel multi-frontal solver for Grids with point singularities
(2015) Gurgul, Piotr; Paszyński, Maciej; Paszyńska, Anna
This paper describes the application of hypergraph grammars to drive a linear computational cost solver for grids with point singularities. Such graph grammar productions are the first mathematical formalisms used to describe solver algorithms, and each indicates the smallest atomic task that can be executed in parallel, which is very useful in the case of parallel execution. In particular, the partial order of execution of graph grammar productions can be found, and the sets of independent graph grammar productions can be localized. They can be scheduled set by set into a shared memory parallel machine. The graphgrammar-based solver has been implemented with NVIDIA CUDA for GPU. Graph grammar productions are accompanied by numerical results for a 2D case. We show that our graph-grammar-based solver with a GPU accelerator is, by order of magnitude, faster than the state-of-the-art MUMPS solver.
Artykuł
Dostęp ograniczony
Towards a Novel environment for simulation of Quantum Computing
(2015) Patrzyk, Joanna; Patrzyk, Bartłomiej; Rycerz, Katarzyna; Bubak, Marian
In this paper, we analyze existing quantum computer simulation techniques and their realizations to minimize the impact of the exponential complexity of simulated quantum computations. As a result of this investigation, we propose a quantum computer simulator with an integrated development environment – QuIDE – supporting the development of algorithms for future quantum computers. The simulator simplifies building and testing quantum circuits and understanding quantum algorithms in an efficient way. The development environment provides flexibility of source code edition and ease of the graphical building of circuit diagrams. We also describe and analyze the complexity of algorithms used for simulation as well as present performance results of the simulator as well as results of its deployment during university classes.