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Found 6273 publications

A possible extension of the Aboav-Wealre law

Ibolya Zsoldos Tamás Réti

Publication Name: Materials Science Forum

Publication Date: 2005-01-01

Volume: 473-474

Issue: Unknown

Page Range: 389-398

Description:

The semi-empirical Aboav-Weaire law is generally used to characterize the local topological correlation between the neighbor cells in 2D space-filling random cellular system. Starting with a possible generalization of the Aboav-Weaire law, this paper presents a new method, which is designated primarily to the topological characterization of finite cellular systems defined on an unbounded, closed and orientable surface, and composed of a finite set of combinatorial polygons. It is demonstrated that using two simple topological parameters (AR and ER) derived from the extended Aboav-Weaire equation, the local structure and the stability of polyhedral fullerenes can be efficiently evaluated on the basis of quantitative criteria. © 2005 Trans Tech Publications, Switzerland.

Open Access: Yes

DOI: 10.4028/0-87849-957-1.389

Numerical methods for safeguarding the performance of the quenching process

S. Sarmiente Imre Felde S. Segerberg Tamás Réti J. Bodin

Publication Name: Materials Science Forum

Publication Date: 2005-01-01

Volume: 473-474

Issue: Unknown

Page Range: 335-340

Description:

ivf SmartQuench™ - a new system for testing and evaluation of quenching media and quenching systems - has recently been introduced by IVF. One of the system main features is an advanced computer software, which provides flexible evaluation of quenchants in many respects. The abilities of the computer program is underlined. © 2005 Trans Tech Publications, Switzerland.

Open Access: Yes

DOI: 10.4028/0-87849-957-1.335

Energy conservative algorithm for numerical solution of ODEs initial value problems

E. M. Miletics

Publication Name: Journal of Computational Methods in Sciences and Engineering

Publication Date: 2005-01-01

Volume: 5

Issue: 1

Page Range: 39-45

Description:

The numerical treatment of the ODE initial value problems is an intensively researched field. Recently the qualitative algorithms, such as monotonicity and positivity preserving algorithms are in the focus of investigation. For the dynamical systems the energy conservative algorithms are very important. In the case of Hamiltonian system the symplectic algorithms are very effective. This kind of algorithm is not adaptive, but doubtless they are powerful. The high-efficiency computers and the computer algebraic software systems allow us to create efficient adaptive energy conservative numerical algorithm for solving ODE initial value problems. In this article an adaptive numerical-analytical algorithm is suggested which very effectively can be applied for Hamiltonian systems, but the idea of construction can be adaptable for other initial value problems too, where there are some quantity preserved in time. The idea and the efficiency of the proposed algorithm will be presented by simple examples, such as the Lotka-Volterra and linear oscillator problems.

Open Access: Yes

DOI: 10.3233/jcm-2005-5104

Filtering and contrast enhancement on subtracted direct digital angiograms

B. Benyo L. Nagy

Publication Name: Annual International Conference of the IEEE Engineering in Medicine and Biology Proceedings

Publication Date: 2004-12-01

Volume: 26 II

Issue: Unknown

Page Range: 1533-1536

Description:

This paper presents the results of a research related to medical image subtraction algorithms. The selected area is of direct digital X-Ray angiography, where subtraction algorithms are the basis of most acquisition and reviewing protocols. The goal of this research is to analyze the currently existing image subtraction algorithms and to propose a new approach based on the experienced limitations, respectively to develop a new imaging technique that allows both contrast agent and radiation dose reduction. The enhancement of the subtraction algorithms is targeted by two means: a) noise reduction on image frames, b) identification of contrast agent injected regions. Both aspects will be studied based on the analysis of the spatio-temporal signal variation that image pixel intensities represent, therefore the resulting algorithm can not be used real time during image acquisition, but as a post processing technique during review. The temporal variation of pixel intensities was then analyzed and a patter check was followed to identify pixels being part of a contrast agent injected region. This information was used to highlight regions of interest and to increase the contrast in poorly injected areas.

Open Access: Yes

DOI: DOI not available

Slewing of rubber-sprung wheels with railway vechiles

László Kiss László Bozóky Vince Nagy

Publication Name: Proceedings of the Mini Conference on Vehicle System Dynamics Identification and Anomalies

Publication Date: 2004-12-01

Volume: Unknown

Issue: Unknown

Page Range: 171-175

Description:

The slewing of railway vehicle's rubber-spring wheel means that the wheel has an elastic and plastic change in angle relative to the wheel frame. This study has the objective to explore the evolution and the causes for these angle changes both in laboratory environment and also during the running of the vehicle.

Open Access: Yes

DOI: DOI not available

Characterization of the temporal pattern of cerebral blood flow oscillations

Gábor Lenzsér B. Benyo Béla Paláncz

Publication Name: IEEE International Conference on Neural Networks Conference Proceedings

Publication Date: 2004-12-01

Volume: 3

Issue: Unknown

Page Range: 2467-2470

Description:

Oscillation of the cerebral blood flow (CBF) is a common feature in several physiological or pathophysiological states of the brain. It is a promising opportunity to identify the state of the brain based on the classification of CBF signals. In order to carry out classification of the time signals, a feature vector has been extracted to characterize the signals. Unsupervised classification showed that the extracted feature vector is an acceptable representation of the time signals. It also turned out that the difference between normal signal and a signal indicating drug injection effect is significant, and much more dominant than the difference between signals of the right and left brain sides. For the signal classification an Artificial Neural Network (ANN) model based on supervised backpropagation network has been developed and successfully applied.

Open Access: Yes

DOI: 10.1109/IJCNN.2004.1381016

Logic testing of CMOS structures

No authors available

Publication Name: ICCC 2004 - Second IEEE International Conference on Computational Cybernetics, Proceedings

Publication Date: 2004-12-01

Volume:

Issue:

Page Range: 59-64

Description:

The paper presents a test calculation principle which serves for producing tests of switch-level logic faults in CMOS digital circuits. The considered fault model includes stuck-at-0/1 logic faults on the connecting lines, as well as switch faults in the transistors. Both single and multiple faults are included. The transistor faults manifest themselves in stuck open (open circuit) and stuck short (short circuit) behavior. In this paper only combinational logic circuits are taken into consideration. The calculation principle is comparatively simple. It is based only on successive line-value justification, and it yields an opportunity to be realized by an efficient computer program. ©2004 IEEE.

Open Access: No

DOI: DOI not available

Spatially aggregated data and variables in empirical analysis and model building for economics

No authors available

Publication Name: CyberGeo

Publication Date: 2004-12-01

Volume: 2004

Issue:

Page Range: Unknown

Description:

A short review of the importance of spatial aggregation problem in general and specially in economics is followed by a typology of spatial analysis and statistical data from spatial aggregation viewpoint. The modifiable areal unit problem is divided into two parts. There are the scale and the zoning system effects, which are illustrated using Hungarian data. Spatial data aggregation creates the need for investigating the connection between the theory and data as well as the micro-macro dualism.

Open Access: No

DOI: DOI not available

Slewing of rubber-sprung wheels with railway vechiles

No authors available

Publication Name: Proceedings of the Mini Conference on Vehicle System Dynamics, Identification and Anomalies

Publication Date: 2004-12-01

Volume:

Issue:

Page Range: 171-175

Description:

The slewing of railway vehicle's rubber-spring wheel means that the wheel has an elastic and plastic change in angle relative to the wheel frame. This study has the objective to explore the evolution and the causes for these angle changes both in laboratory environment and also during the running of the vehicle.

Open Access: No

DOI: DOI not available