Computer Science
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ISSN 1508-2806
e-ISSN: 2300-7036
Issue Date
2016
Volume
Vol. 17
Number
No. 4
Description
Reviewed by: Arnd Meyer, Mikhail Moshkov, Ignatio Gomez-Revuelto, Pawel Czarnul, Daniel Hernandez, Javier Alonso, Manuj Darbari, Emir Ozder, Marek Makowski, Zbigniew Michalewicz, Adam Jatowt, George Ghinea, Pawel Swiatek, Piotr Breitkopf, Joanna Plazek
Journal Volume
Computer Science
Vol. 17 (2016)
Projects
Pages
Articles
One-dimensional fully automatic h-adaptive isogeometric finite element method package
(Wydawnictwa AGH, 2016) Lipski, Paweł; Paszyński, Maciej
This paper deals with an adaptive finite element method originally developed by Prof. Leszek Demkowicz for hierarchical basis functions. In this paper, we investigate the extension of the adaptive algorithm for isogeometric analysis performed with $B$-spline basis functions. We restrict ourselves to $h$-adaptivity, since the polynomial order of approximation must be fixed in the isogeometric case. The classical variant of the adaptive FEM algorithm, as delivered by the group of Prof. Demkowicz, is based on a two-grid paradigm, with coarse and fine grids (the latter utilized as a reference solution). The problem is solved independently over a coarse mesh and a fine mesh. The fine-mesh solution is then utilized as a reference to estimate the relative error of the coarse-mesh solution and to decide which elements to refine. Prof. Demkowicz uses hierarchical basis functions, which (though locally providing $C^{p−1}$ continuity) ensure only $C^0$ on the interfaces between elements. The CUDA C library described in this paper switches the basis to $B$-spline functions and proposes a one-dimensional isogeometric version of the $h$-adaptive FEM algorithm to achieve global $C^{p−1}$ continuity of the solution.
Simulation-based sailboat trajectory optimization using on-board heterogeneous computers
(Wydawnictwa AGH, 2016) Dębski, Roman
A dynamic programming-based algorithm adapted to on-board heterogeneous computers for simulation-based trajectory optimization was studied in the context of high-performance sailing. The algorithm can efficiently utilize all OpenCL-capable devices, starting the computation (if necessary, in singleprecision) on a GPU and finalizing it (if necessary, in double-precision) with the use of a CPU. The serial and parallel versions of the algorithm are presented in detail. Possible extensions of the basic algorithm are also described. The experimental results show that contemporary heterogeneous on-board/mobile computers can be treated as micro HPC platforms. They offer high performance (the OpenCL-capable GPU was found to accelerate the optimization routine 41 fold) while remaining energy and cost efficient. The simulation-based approach has the potential to give very accurate results, as the mathematical model upon which the simulator is based may be as complex as required. The black-box represented performance measure and the use of OpenCL make the presented approach applicable to many trajectory optimization problems.
An octopus-inspired intrusion deterrence model in distributed computing system
(Wydawnictwa AGH, 2016) Olajubu, Emmanuel A.; Akinwale, Abiodun; Ogundoyin, Kazeem Ibraheem
The study formulated and evaluated a model for effective management of malicious nodes in mobile Ad-hoc network based on Ad-Hoc on- demand distance vector routing protocol. A collaborative injection model called Collaborative Injection Deterrence Model (CIDM) was formulated using stochastic theory. The definition of the model was presented using graph theory. CIDM was simulated using three different scenarios. The three scenarios were then compared using packets delivery ratio (PDR), routing load, throughput and delay as performance metrics. The simulation result showed that CIDM reduce considerably the rate of packets dropped caused by malicious nodes in MANET network. CIDM did not introduce additional load to the network and, yet produce higher throughput. Lastly, the access delay in CIDM is minimal compared with convectional OADV. The study developed a model to mete out a punitive measure to rogue nodes as a form of intrusion deterrence without degrading the overall performance of the network. The well known CRAWDAD dataset was used in the simulation.
Application of multi-criteria analysis based on individual psychological profile for recommender systems
(Wydawnictwa AGH, 2016) Rafalak, Maria; Granat, Janusz; Wierzbicki, Andrzej P.
This paper presents a novel approach for user classification exploiting multicriteria analysis. This method is based on measuring the distance between an observation and its respective Pareto front. The obtained results show that the combination of the standard KNN classification and the distance from Pareto fronts gives satisfactory classification accuracy - higher than the accuracy obtained for each of these methods applied separately. Conclusions from this study may be applied in recommender systems where the proposed method can be implemented as the part of the collaborative filtering algorithm.
Notification methods in wireless systems
(Wydawnictwa AGH, 2016) Nawrocki, Piotr; Jakubowski, Mikołaj; Godzik, Tomasz
Recently, there has been an increasing need for secure, efficient, and simple notification methods for wireless systems. Such systems are meant to provide users with precise tools best suited for work or leisure environments, and a lot of effort has been put into creating a multitude of applications. At the same time, however, not much research has been made into determining which of the available protocols are best suited for each individual task. A number of basic notification methods are presented here, and tests have been performed for the most-promising ones. An attempt has been made to determine which of the methods have the best throughput, latency, security, and other characteristics. A comprehensive comparison is provided, which can be used to select the right method for each individual project. Finally, conclusions are provided, and the results from all of the tests conducted are discussed.