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Found 5152 publications

Dimensioning of the reinforced concrete structures old and new presrciptions in Hungary

Csaba Kegyes

Publication Name: Proceedings of the Fib Symposium 2003 Concrete Structures in Seismic Regions

Publication Date: 2003-01-01

Volume: Unknown

Issue: Unknown

Page Range: 264-265

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Correlation between the mechanical and the geometrical state of railway vehicle carriages

No authors available

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

Publication Date: 2002-12-01

Volume:

Issue:

Page Range: 261-269

Description:

The railway vehicle's carriage body must be mechanically repaired if cracks appear in its structure. In such cases all factors concerning the mechanical state of the carriage body should be examined, such as connection between the carriages, adjustment of the wheel forces, the different running states and running on straight and curved track. The aim of this study is to provide the mechanical stress values summarising the simultaneous effects of all these factors.

Open Access: No

DOI: DOI not available

A meshless boundary element technique based on multi-level iterated Helmholtz-type interpolation

Csaba Gáspár

Publication Name: International Series on Advances in Boundary Elements

Publication Date: 2002-12-01

Volume: 13

Issue: Unknown

Page Range: 105-114

Description:

A special scattered data interpolation technique is introduced. The interpolation problem is converted to a higher order auxiliary PDE, typically to an iterated Laplace or Helmholtz equation. To solve this PDE, robust multilevel methods are used which are based on a quadtree/octtree subdivision algorithm. Thus, the solution of large interpolation equations are avoided. Using this interpolation method, meshless techniques are constructed which require a set of boundary points only, without any structure. Theoretical results as well as numerical examples are also presented.

Open Access: Yes

DOI: DOI not available

On the relational database type numerical programming

B. Kiss A. Krebsz

Publication Name: Proceedings of the Third International Conference on Engineering Computational Technology

Publication Date: 2002-12-01

Volume: Unknown

Issue: Unknown

Page Range: 127-128

Description:

The numerical algorithms became quite complex and require dynamic data structures. As such, an advanced front (AF) algorithm which is a well-known and efficient algorithm of the non-structural mesh generation is given. An accelerated version of this algorithm is presented as an example to demonstrate, that a simplified relational database model is an efficient tool for handling dynamic data structures arising from numerical problems. The main advantage of this technique is the simple and uniform data structure and the application of the balanced trees for searching and modification.

Open Access: Yes

DOI: DOI not available

Correlation between the mechanical and the geometrical state of railway vehicle carriages

Lajos Borbás Laszlo Bozoky Vince Nagy

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

Publication Date: 2002-12-01

Volume: Unknown

Issue: Unknown

Page Range: 261-269

Description:

The railway vehicle's carriage body must be mechanically repaired if cracks appear in its structure. In such cases all factors concerning the mechanical state of the carriage body should be examined, such as connection between the carriages, adjustment of the wheel forces, the different running states and running on straight and curved track. The aim of this study is to provide the mechanical stress values summarising the simultaneous effects of all these factors.

Open Access: Yes

DOI: DOI not available

A numerical C1-shadowing result for retarded functional differential equations

Gyula Farkas

Publication Name: Journal of Computational and Applied Mathematics

Publication Date: 2002-08-15

Volume: 145

Issue: 2

Page Range: 269-289

Description:

The aim of the present paper is to give a numerical C1-shadowing between the exact solutions of a functional differential equation and its numerical approximations. The shadowing result is obtained by comparing exact solutions with numerical approximation which do not share the same initial value. Behavior of stable manifolds of functional differential equations under numerics will follow from the shadowing result. © 2001 Elsevier Science B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/S0377-0427(01)00581-7

Construction of two-sided bounds for initial-boundary value problems

C. Grossmann Zoltán Horváth

Publication Name: Applied Numerical Mathematics

Publication Date: 2002-08-01

Volume: 42

Issue: 1-3

Page Range: 177-187

Description:

The present paper extends the bounding operator approach developed for boundary value problems to the case of initial-boundary value problems (IBVPs). Following the general principle of bounding operators enclosing methods for the case of partial differential equations are discussed. In particular, continuous discretization methods with an appropriate error bound controlled shift and monotone extensions of Rothe's method for parabolic problems are investigated. © 2001 IMACS. Published by Elsevier Science B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/S0168-9274(01)00149-0

An update on recurrent acute pancreatitis: Data from five European countries

Gyula Farkas Hans Beger Paul Lankisch Philippe Levy Raffaele Pezzilli Lucio Gullo Constantine Arvanitakis Marina Migliori Attila Oláh

Publication Name: American Journal of Gastroenterology

Publication Date: 2002-08-01

Volume: 97

Issue: 8

Page Range: 1959-1962

Description:

OBJECTIVE: A great number of studies have been published on acute pancreatitis, but few have focused on the recurrent form. In this study, we have sought to determine the relative frequency and mortality of recurrent acute pancreatitis, and also to update our knowledge of its etiological factors. METHODS: Patients were selected from a total of 1068 persons included in a previous European study of acute pancreatitis. All were admitted to a hospital with an attack of acute pancreatitis between January, 1990 and December, 1994. Data for each patient was recorded on a standardized form. RESULTS: Of the 1068 with acute pancreatitis, 288 (27%) had recurrent pancreatitis; the majority (78.8%) were men, with a mean age of 43 yr (range 16-95 yr). Regarding etiology, alcohol was the most frequent factor (57%), followed by gallstones (25%), other factors (7.6%), and no identified factor (10.4%). Of the 288 patients, 17 (5.9%) died, all of whom had necrotizing pancreatitis; among all of the patients with necrotizing pancreatitis (141 of 288), the mortality was 12.1%. These percentages are lower than those for patients who had a single attack (8.5% and 18.6%, respectively), but not to a statistically significant degree. Mortality was significantly lower among patients with alcoholic pancreatitis (6.9%) than among those with biliary (30%) (p < 0.002) or idiopathic pancreatitis (25%) (p < 0.04). Most of the deaths (82.4%) occurred at the second attack of pancreatitis. CONCLUSION: Acute recurrent pancreatitis remains a frequent disease, with alcohol being the most frequent etiological factor. Mortality is similar to that of a single episode of acute pancreatitis, and it is significantly lower among patients with alcohol as the etiology. © 2002 by Am. Coll. of Gastroenterology.

Open Access: Yes

DOI: 10.1016/S0002-9270(02)04264-8

Nonexistence of uniform exponential dichotomies for delay equations

Gyula Farkas

Publication Name: Journal of Differential Equations

Publication Date: 2002-06-10

Volume: 182

Issue: 1

Page Range: 266-268

Description:

No description provided

Open Access: Yes

DOI: 10.1006/jdeq.2001.4156