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Found 6289 publications

Fast algorithm to solve the most economical path problem in sparse matrices

K. Ambrus-Somogyi J. Gati András Bakó Peter Foldesi

Publication Name: Ines 2012 IEEE 16th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2012-10-01

Volume: Unknown

Issue: Unknown

Page Range: 335-339

Description:

Several variations exist of the shortest path problem depending on the type of the graph. The most common problems are the shortest path problem between two points and between every pair of points (the so called multiterminal minimal path problem). Beside this several other variations are known. One of them is the shortest path in a network having gains, the time dependent path, the shortest path in a network, where the travelling time depends on the actual traffic flow. In this paper a powerful algorithm is presented in large scale, sparse network. In long term road network planning problem sometimes the size of the network is very large - about hundred thousand. The network is usually sparse, one point is connected with average 3 or 4 points. It will be shown that the presented algorithm in this case is much more powerful. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/INES.2012.6249854

Comparative analysis of parallel gene transfer operators in the bacterial evolutionary algorithm

Miklós F. Hatwágner András Horváth

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2012-09-18

Volume: 9

Issue: 4

Page Range: 65-84

Description:

The Bacterial Evolutionary Algorithm (BEA) is an evolutionary method, originally meant to optimize the parameters of fuzzy systems. The authors have already proposed three modified versions of the original algorithm in a previous paper to make it usable in engineering applications with time-consuming object functions as well. Section 1 summarizes the earlier results. It presents the operators of the original BEA and the suggested parallel version. In Section 2, the optimal parameter settings and the analytical estimation of wall clock time in parallel computations are investigated. In Section 3, the paper deals with genetic diversity in different BEA versions. The effect of the modified gene transfer operators on genetic diversity is measured. The conclusion is that the proposed methods have quite good efficiency in all cases, and we can reach the ideal case if we have full control over the parameters.

Open Access: Yes

DOI: DOI not available

A simple method to forecast travel demand in urban public transport

Balázs Horváth

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2012-09-17

Volume: 9

Issue: 4

Page Range: 165-176

Description:

The key to the planning of public transport systems is the accurate prediction of the traffic load, or the correct execution of the planning stage assignment. This requires not only a well-functioning assignment method, but also reliable passenger data. Reliable passenger data means a time-dependent origin-destination matrix. To solve the problem of the lack of time-dependent passenger data, we have developed a forecasting method. It consists of three stages. In the first stage, we collect full scope cross-section data. This can be done either with personnel or with an automatic counting system. If personnel are used it costs a lot, and there is the chance for many possible errors. However, the results in most cases are good enough. Automatic counting system can be either a counter machine or even a simple Check in E-ticketing system. In the second stage, we link boarding and alighting. As result, we get the origin-destination matrix for each run. This method is based on the likelihood of alighting at a given stop. In the third stage, we combine origin-destination matrices of the runs through transfers. At this stage we assume that the probability of a transfer between two runs in a given stop is proportional to the travel possibilities in this relation. To view the entire method in practice we proved it in a Hungarian city (Dunaújváros). The results were reliable, so they could be used in the planning process.

Open Access: Yes

DOI: DOI not available

Mergers and acquisitions in the law of the European union and their economical background

István Dobos

Publication Name: Acta Juridica Hungarica

Publication Date: 2012-09-01

Volume: 53

Issue: 3

Page Range: 218-235

Description:

The purpose of this paper is to discuss the mergers and acquisitions activity from various perspectives. The concept of mergers and acquisitions always has a strong economic background, which will be considered even if the concept is discussed from a legal perspective. After clarification of the basic terms of mergers and acquisitions, the economic background of mergers and acquisitions will be examined. From legal point of view this paper mainly concentrates on the relevant directives of the European Union. Currently, there are four relevant company law directives related to corporate reconstruction in the law of the European Union: the Merger Directive, which regulates mergers between public companies, the Sixth Company Law Directive, which covers the division of an existing public company into entities, the directive, which concerns cross-border mergers and last but not least the Takeover Directive. From this four company law directives, this paper mainly focuses, besides the economical background and basic terms of mergers, on the Merger and Cross-Border Directive.

Open Access: Yes

DOI: 10.1556/AJur.53.2012.3.4

Graphene-based molecular dynamics nanolithography of fullerenes, nanotubes and other carbon structures

Ibolya Zsoldos István László

Publication Name: Epl

Publication Date: 2012-09-01

Volume: 99

Issue: 6

Page Range: Unknown

Description:

The mass production of fullerenes and nanotubes faces the problem of their selective production. Here we present special kind of graphene patterns which can be used as initial structures for fullerenes, nanotubes and other carbon nanostructures. We proved in quantum chemical molecular dynamics calculations that these structures transform in a self-organizing way into the desired structures. Our results can initiate new experimental researches for improving the existing carbon nanostructure productions and to develop a new, structure-selective nanolithography of fullerenes, nanotubes and other carbon structures. We present such kind of graphene patterns which generate the self-organizing processes. In our molecular dynamics simulation we obtained the C 60 and C 70 fullerene, the (5,5) armchair nanotube and (9,0) zigzag nanotube. We present also a graphene pattern for self-organizing Y junction production. © Copyright EPLA, 2012.

Open Access: Yes

DOI: 10.1209/0295-5075/99/63001

Parallel implementation of a combustion chamber simulation with MPI-OpenMP hybrid techniques

László Környei

Publication Name: Mipro 2012 35th International Convention on Information and Communication Technology Electronics and Microelectronics Proceedings

Publication Date: 2012-08-22

Volume: Unknown

Issue: Unknown

Page Range: 356-361

Description:

The parallelization techniques utilized in a study of gas flow in a combustion chamber are described and discussed in this paper. Models of compressible fluid dynamics are solved with the finite volume method, and an additional algorithm, called "snapper" that handles piston and valve movement. In order to achieve an acceptable scaling on a CPU cluster with 240 cores, a two-stage parallelization with MPI in conjecture with OpenMP is implemented. For some types of physical investigations, the actual spatial region of interest is somehow changing, deforming, or moving in time in a predefined fashion. Handling gas dynamics with piston motion, even with the simplest models requires precaution. Apart from numerical and physical corrections, there are challenges, where multiple types of unstructured, and specially generated deforming grids are handled in a computer system with distributed memory. In the present work the results of the first implementations and benchmarks are presented, which prove to be well scaling for this modest-sized cluster. © 2012 MIPRO.

Open Access: Yes

DOI: DOI not available

Extending the functional training approach for B-splines

Pedro M. Ferreira Cristiano L. Cabrita António E. Ruano László T. Kóczy

Publication Name: Proceedings of the International Joint Conference on Neural Networks

Publication Date: 2012-08-22

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

When used for function approximation purposes, neural networks belong to a class of models whose parameters can be separated into linear and nonlinear, according to their influence in the model output. This concept of parameter separability can also be applied when the training problem is formulated as the minimization of the integral of the (functional) squared error, over the input domain. Using this approach, the computation of the gradient involves terms that are dependent only on the model and the input domain, and terms which are the projection of the target function on the basis functions and on their derivatives with respect to the nonlinear parameters, over the input domain. This paper extends the application of this formulation to B-splines, describing how the Levenberg-Marquardt method can be applied using this methodology. Simulation examples show that the use of the functional approach obtains important savings in computational complexity and a better approximation over the whole input domain. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/IJCNN.2012.6252741

Parallel implementation of a combustion chamber simulation with MPI-OpenMP hybrid techniques

No authors available

Publication Name: MIPRO 2012 - 35th International Convention on Information and Communication Technology, Electronics and Microelectronics - Proceedings

Publication Date: 2012-08-22

Volume:

Issue:

Page Range: 356-361

Description:

The parallelization techniques utilized in a study of gas flow in a combustion chamber are described and discussed in this paper. Models of compressible fluid dynamics are solved with the finite volume method, and an additional algorithm, called "snapper" that handles piston and valve movement. In order to achieve an acceptable scaling on a CPU cluster with 240 cores, a two-stage parallelization with MPI in conjecture with OpenMP is implemented. For some types of physical investigations, the actual spatial region of interest is somehow changing, deforming, or moving in time in a predefined fashion. Handling gas dynamics with piston motion, even with the simplest models requires precaution. Apart from numerical and physical corrections, there are challenges, where multiple types of unstructured, and specially generated deforming grids are handled in a computer system with distributed memory. In the present work the results of the first implementations and benchmarks are presented, which prove to be well scaling for this modest-sized cluster. © 2012 MIPRO.

Open Access: No

DOI: DOI not available

Signatures: Definitions, operators and applications to fuzzy modelling

Claudiu Radu Pozna Áron Ballagi Nicuşor Minculete Radu Emil Precup László T. Kóczy

Publication Name: Fuzzy Sets and Systems

Publication Date: 2012-08-16

Volume: 201

Issue: Unknown

Page Range: 86-104

Description:

This paper presents a new framework for the symbolic representation of data which is referred to as signatures. The definitions of signatures and of signature trees are first given. Original operators on signatures are next presented, i.e., contraction, extension, pruning, addition, multiplication, and grafting. Attractive applications of signatures related to the modelling of fuzzy inference systems are suggested and discussed. An example is included to accompany the theoretical results. © 2012 Elsevier B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/j.fss.2011.12.016