Numer czasopisma
Computer Science
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ISSN: 1508-2806
e-ISSN:
Data wydania
2016
Rocznik
Vol. 17
Numer
No. 4
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. 17 (2016)
Artykuły numeru (rel.)
Artykuł
Dostęp ograniczony
One-dimensional fully automatic h-adaptive isogeometric finite element method package
(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 Cp−1 continuity) ensure only C0 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 Cp−1 continuity of the solution.
Artykuł
Dostęp ograniczony
Simulation-based sailboat trajectory optimization using on-board heterogeneous computers
(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.
Artykuł
Dostęp ograniczony
An octopus-inspired intrusion deterrence model in distributed computing system
(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.
Artykuł
Dostęp ograniczony
Application of multi-criteria analysis based on individual psychological profile for recommender systems
(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.
Artykuł
Dostęp ograniczony
Notification methods in wireless systems
(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.
Artykuł
Dostęp ograniczony
Tree structures for adaptive control space in 3D meshing
(2016) Jurczyk, Tomasz; Głut, Barbara
The article presents a comparison of several octree- and kd-tree-based structures used for the construction of control space in the process of anisotropic mesh generation and adaptation. The adaptive control space utilized by the authors supervises the construction of meshes by providing the required metric information regarding the desired shape and size of elements of the mesh at each point of the modeled domain. Comparative tests of these auxiliary structures were carried out based on different versions of the tree structures with respect to computational and memory complexity as well as the quality of the generated mesh. Analysis of the results shows that kd-trees (not present in the meshing literature in this role) offer good performance and may become a reasonable alternative to octree structures.