Computer Science
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ISSN 1508-2806
e-ISSN: 2300-7036
Call number
Volume
Vol. 11
Date
2010
Description
Reviewed by: Janusz Jurek, David Pardo, Krzysztof Cetnarowicz, Stanisław Ambroszkiewicz, Aleksander Byrski, Marian Babik, Mariusz Flasiński
Journal
Computer Science
AGH University Press (2004-)
ISSN: 1508-2806 e-ISSN: 2300-7036
ISSN: 1508-2806 e-ISSN: 2300-7036
journal.volume.project
Contains
Journal Issues
Articles
Improvements to Glowworm Swarm Optimization algorithm
(Wydawnictwa AGH, 2010) Oramus, Piotr
Glowworm Swarm Optimization algorithm is applied for the simultaneous capture of multiple optima of multimodal functions. The algorithm uses an ensemble of agents, which scan the search space and exchange information concerning a fitness of their current position. The fitness is represented by a level of a luminescent quantity called luciferin. An agent moves in direction of randomly chosen neighbour, which broadcasts higher value of the luciferin. Unfortunately, in the absence of neighbours, the agent does not move at all. This is an unwelcome feature, because it diminishes the performance of the algorithm. Additionally, in the case of parallel processing, this feature can lead to unbalanced loads. This paper presents simple modifications of the original algorithm, which improve performance of the algorithm by limiting situations, in which the agent cannot move. The paper provides results of comparison of an original and modified algorithms calculated for several multimodal test functions.
Flexible and secure access to computing clusters
(Wydawnictwa AGH, 2010) Meizner, Jan; Malawski, Maciej; Bubak, Marian
The investigation presented in this paper was prompted by the need to provide a manageable solution for secure access to computing clusters with a federated authentication framework. This requirement is especially important for scientists who need direct access to computing nodes in order to run their applications (e.g. chemical or medical simulations) with proprietary, open-source or custom-developed software packages. Our existing software, which enables non-Web clients to use Shibboleth-secured services, has been extended to provide direct SSH access to cluster nodes using the Linux Pluggable Authentication Modules mechanism. This allows Shibboleth users to run the required software on clusters. Validation and performance comparison with existing SSH authentication mechanisms confirm that the presented tools satisfy the stated requirements.
SLA-oriented semi-automatic management of data storage and applications in distributed environments
(Wydawnictwa AGH, 2010) Król, Dariusz; Funika, Włodzimierz; Słota, Renata; Kitowski, Jacek
In this paper we describe a semi-automatic programming framework for supporting users with managing the deployment of distributed applications along with storing large amounts of data in order to maintain Quality of Service in highly dynamic and distributed environments, e.g., Grid. The Polish national PL-GRID project aims to provide Polish science with both hardware and software infrastructures which will allow scientists to perform complex simulations and in-silico experiments on a scale greater than ever before. We highlight the issues and challenges related to data storage strategies that arise at the analysis stage of user requirements coming from different areas of science. Next we present a solution to the discussed issues along with a description of sample usage scenarios. At the end we provide remarks on the current status of the implementation work and some results from the tests performed.
Towards autonomic semantic-based management of distributed applications
(Wydawnictwa AGH, 2010) Funika, Włodzimierz; Kupisz, Mateusz; Koperek, Paweł
In this paper we present our approach to the management of distributed systems based on semantic description of available resources. We use ontologies for a semantic description of the monitored system and other aspects of monitoring and management (such as metrics) and introduce a feedback loop on underlying infrastructure. Such an approach allows to automate monitoring and the ease the work of administrator. We introduce concepts behind a novel automatic management system, SAMM, developed within our research. We discuss the core mechanisms used in the system - the estimation of future measurements, approach to knowledge gathering, and the process of decision making. Then we provide some details on the architecture and implementation of SAMM.
Graph grammar based Petri net controlled direct solver algorithm
(Wydawnictwa AGH, 2010) Szymczak, Arkadiusz; Paszyński, Maciej; Pardo, David
In this paper we present the Petri net setting the optimal order of elimination for direct solver working with hp refined finite finite element meshes. The computational mesh is represented by a graph, with graph vertices corresponding to finite element nodes. The direct solver algorithm is expressed as a sequence of graph grammar productions, attributing the graph vertices. The Petri net dictates the order of graph grammar productions, representing the execution of the solver algorithm over a graph representation of computational mesh. The presentation is concluded with numerical experiments performed for a model L-shape domain.