Search in Publications

Found 6289 publications

Virtual localization by blind persons

György Wersényi

Publication Name: AES Journal of the Audio Engineering Society

Publication Date: 2012-07-01

Volume: 60

Issue: 7-8

Page Range: 568-579

Description:

Localization performance and spatial hearing abilities of blind persons are complex issues. In everyday life we rely on the "fact" that blind people can hear better, without thinking of what "better" means. Localization performance depends on many parameters such as properties of the excitation signal, environmental conditions, individual aspects, and visual influence. Our goal was to create a virtual environment aimed at helping the blind community use personal computers. In developing this environment we were concerned to cover technical and hearing related questions, as well as human factors. At first, this project included sighted subjects and basic properties of the virtual audio system and the applied HRTFs were tested. Subsequently, blind persons have been involved and comparative measurements performed using the same equipment and selected localization tasks. Twenty-eight blind person's localization performances were tested and compared with the results of 40 sighted subjects in a virtual audio environment. Blind subjects tended to be better in detecting movements in the horizontal plane around the head, localizing static frontal audio sources, and orientation in a 2-D virtual audio display. On the other hand, sighted subjects performed better identifying ascending sound sources in the vertical plane and detecting static sources in the back. In-the-head localization error rates and MAA results appeared to be about the same for both groups. The evaluation was also supported by some informal questions.

Open Access: Yes

DOI: DOI not available

Virtual localization by blind persons

No authors available

Publication Name: AES: Journal of the Audio Engineering Society

Publication Date: 2012-07-01

Volume: 60

Issue: 7-8

Page Range: 568-579

Description:

Localization performance and spatial hearing abilities of blind persons are complex issues. In everyday life we rely on the "fact" that blind people can hear better, without thinking of what "better" means. Localization performance depends on many parameters such as properties of the excitation signal, environmental conditions, individual aspects, and visual influence. Our goal was to create a virtual environment aimed at helping the blind community use personal computers. In developing this environment we were concerned to cover technical and hearing related questions, as well as human factors. At first, this project included sighted subjects and basic properties of the virtual audio system and the applied HRTFs were tested. Subsequently, blind persons have been involved and comparative measurements performed using the same equipment and selected localization tasks. Twenty-eight blind person's localization performances were tested and compared with the results of 40 sighted subjects in a virtual audio environment. Blind subjects tended to be better in detecting movements in the horizontal plane around the head, localizing static frontal audio sources, and orientation in a 2-D virtual audio display. On the other hand, sighted subjects performed better identifying ascending sound sources in the vertical plane and detecting static sources in the back. In-the-head localization error rates and MAA results appeared to be about the same for both groups. The evaluation was also supported by some informal questions.

Open Access: No

DOI: DOI not available

Timed cooperative multitask for tiny real-time embedded systems

József Kopják Janos Kovacs

Publication Name: IEEE 10th Jubilee International Symposium on Applied Machine Intelligence and Informatics Sami 2012 Proceedings

Publication Date: 2012-06-29

Volume: Unknown

Issue: Unknown

Page Range: 377-382

Description:

The paper present alternative multitasking kernel algorithm used in tiny real-time embedded systems, microcontrollers. The paper first reviews the basics of realtime systems and traditional programming models used in embedded systems, like sequential programming model and traditional cooperative multitasking model. Greater part of article presents an alternative multitasking programming model, the timed cooperative multitasking. The authors take the reader through the process of kernel design based on timed cooperative multitasking model. The paper ends with demonstration of event-driven model used in timed cooperative multitasking model. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/SAMI.2012.6208993

On the differences of the discrete weak and strong maximum principles for elliptic operators

Miklós E. Mincsovics Tamás L. Horváth

Publication Name: Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics

Publication Date: 2012-06-06

Volume: 7116 LNCS

Issue: Unknown

Page Range: 614-621

Description:

When choosing a numerical method to approximate the solution of a continuous mathematical problem, we need to consider which method results in an approximation that is not only close to the solution of the original problem, but possesses the important qualitative properties of the original problem, too. For linear elliptic problems the main qualitative properties are the various maximum principles. The preservation of the weak maximum principle was extensively investigated in the last decades, but not the strong maximum principle preservation. In this paper we focus on the latter property by giving its necessary and sufficient conditions, investigating the relation of the preservation of the strong and weak maximum principles and illustrating the differences between them with numerous examples. © 2012 Springer-Verlag.

Open Access: Yes

DOI: 10.1007/978-3-642-29843-1_70

Performance analysis of DNS64 and NAT64 solutions

Gabor Takacs Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2012-06-01

Volume: 4

Issue: 2

Page Range: 29-36

Description:

The need for DNS64 and NAT64 solutions is introduced and their operation is presented. A test environment for the performance analysis of DNS64 and NAT64 implementations is described. The resource requirements of the implementations are measured. The performance of DNS64 and NAT64 solutions is measured under heavy load conditions to determine if they are safe to be used in a production environment, like the network of an internet service provider.

Open Access: Yes

DOI: DOI not available

Inverse energy cascade and turbulent transport in a quasi-two-dimensional magnetized electrolyte system: An experimental study

M. Berta L. Bardóczi A. Bencze

Publication Name: Physical Review E Statistical Nonlinear and Soft Matter Physics

Publication Date: 2012-05-30

Volume: 85

Issue: 5

Page Range: Unknown

Description:

We present an experimental study of the inverse energy cascade, spectral condensation, and turbulent particle transport in an electromagnetically driven thin layer of NaCl electrolyte. The presence of the bottom friction provides an energy sink at large scales for the turbulent flow. This energy sink crucially contributes to the balance of the forcing and dissipation which makes the inverse cascade steady. The present work provides an estimation of the linear dissipation rate on an experimental basis. We also show how the dissipation rate affects the characteristic features of the velocity spectrum and the dynamics of the spectral condensation. A quantitative study of the turbulent diffusion shows a significant decrease of the radial transport during the spectral condensation process. © 2012 American Physical Society.

Open Access: Yes

DOI: 10.1103/PhysRevE.85.056315

Different Chromosome-based Evolutionary Approaches for the Permutation Flow Shop Problem

Krisztián Balázs László T. Kóczy Zoltán Horváth

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2012-05-28

Volume: 9

Issue: 2

Page Range: 115-138

Description:

This paper proposes approaches for adapting chromosome-based evolutionary methods to the Permutation Flow Shop Problem. Two types of individual representation (i.e. encoding methods) are proposed, which are applied on three different chromosome based evolutionary techniques, namely the Genetic Algorithm, the Bacterial Evolutionary Algorithm and the Particle Swarm Optimization method. Both representations are applied on the two former methods, whereas one of them is used for the latter optimization technique. Each mentioned algorithm is involved without and with local search steps as one of its evolutionary operators. Since the evolutionary operators of each technique are established according to the applied representation, this paper deals with a total number of ten different chromosome-based evolutionary methods. The obtained techniques are evaluated via simulation runs carried out on the well-known Taillard's benchmark problem set. Based on the experimental results the approaches for adapting chromosome based evolutionary methods are compared to each other.

Open Access: Yes

DOI: DOI not available

Aspects concerning the observation process modelling in the framework of cognition processes

Claudiu Radu Pozna Radu Emil Precup

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2012-04-17

Volume: 9

Issue: 1

Page Range: 203-223

Description:

This paper presents results concerning the observation process modelling in the framework of cognition processes which belong to a new pattern of human knowledge. The cultural origin of the patterns is analyzed in terms of philosophical, psychological and linguistic points of view. A scenario concerning a robot integrated in a cognitive system is given in order to test the theoretical approaches. The definitions of signatures and of signature classes are given as one of the first steps in an alternative modelling approach to the observation process. An example that deals with the observation process modelling is offered.

Open Access: Yes

DOI: DOI not available

Utilizing the inherent electrolysis in a chip-based nanoelectrospray emitter system to facilitate selective ionization and mass spectrometric analysis of metallo alkylporphyrins

Vilmos Kertesz Gary J. Van Berkel

Publication Name: Analytical and Bioanalytical Chemistry

Publication Date: 2012-04-01

Volume: 403

Issue: 2

Page Range: 335-343

Description:

A commercially available chip-based infusion nanoelectrospray ionization system was used to ionize metallo alkylporphyrins for mass spectrometric detection and structure elucidation by mass spectrometry. Different ionic forms of model compounds (nickel (II), vanadyl (II), copper (II), and cobalt (II) octaethylporphyrin) were created by using two different types of conductive pipette tips supplied with the device. These pipette tips provide the conductive contact to solution at which the electrolysis process inherent to electrospray takes places in the device. The original unmodified, bare carbon-impregnated plastic pipette tips were exploited to intentionally electrochemically oxidize (ionize) the porphyrins to form molecular radical cations for detection. Use of modified pipette tips, with a surface coating devised to inhibit analytemass transport to the surface or slow the kinetics of the analyte electrochemical reactions, was shown to limit the ionic species observed in the mass spectra of these porphyrins largely, but not exclusively, to the protonated molecule. Under the conditions of these experiments, the effective upper potential limit for oxidation with the uncoated pipette tip was 1.1 V or less, and the coated pipette tips effectively prevented the oxidation of analytes with redox potentials greater than about 0.25 V. Product ion spectra of either molecular ionic species could be used to determine the alkyl chain length on the porphyrin macrocycle. The utility of this electrochemical ionization approach for the analysis of naturally occurring samples was demonstrated using nickel geoporphyrin fractions isolated from Gilsonite bitumen. Acquiring neutral loss spectra as a means to improve the specificity of detection in these complex natural samples was also illustrated. © Springer-Verlag (outside the USA) 2012.

Open Access: Yes

DOI: 10.1007/s00216-011-5676-x