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Found 6278 publications

Merging of shielded Gaussian vortices and formation of a tripole at low Reynolds numbers

Gábor Tóth Gábor Házi

Publication Name: Physics of Fluids

Publication Date: 2010-01-01

Volume: 22

Issue: 5

Page Range: 1-7

Description:

The interaction between two corotating shielded Gaussian vortices is studied by two-dimensional numerical simulations at low Reynolds numbers. It is shown that the outcome of the interactions can be a shielded monopole, a tripole, or dipolar breaking depending on the initial separation distance and Reynolds number. A flow regime map is given in the parameter space of initial separation distance and Reynolds number. Using formal decomposition for vorticity, we show that the tripole formation is due the same physical mechanism than merging of unshielded vortices, while in dipolar breaking both the symmetric and antisymmetric vorticity contributions play important role. © 2010 American Institute of Physics.

Open Access: Yes

DOI: 10.1063/1.3428539

Approaching the fuzzy road transport Traveling Salesman Problem by eugenic bacterial memetic algorithm

János Botzheim Peter Foldesi

Publication Name: Isciii 09 4th International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2009-12-28

Volume: Unknown

Issue: Unknown

Page Range: 15-22

Description:

The aim of the Traveling Salesman Problem (TSP) is to find the cheapest way of visiting all elements in a given set of cities and returning to the starting point. In solutions presented in the literature costs of travel between nodes (cities) are based on Euclidean distances, the problem is symmetric and the costs are constant. In this paper a novel construction and formulation of the TSP is presented in which the requirements and features of practical application in road transportation and supply chains are taken into consideration. Computational results are presented as well. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2009.5342281

Management of uncertainty in visual examination procedure in building diagnostics with fuzzy expert system

Gergely Molnarka

Publication Name: Isciii 09 4th International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2009-12-28

Volume: Unknown

Issue: Unknown

Page Range: 31-40

Description:

Every building diagnostic analysis begins with a detailed visual check of deteriorations of building elements. During this process the identification of touched components and the circumstances of the given failure are described. A properly completed survey determines the way of further analyses and interventions to be done. Thus the visual check may support indirectly the decisions which deal with the life cycle of the examined building or its part. In the case of ad hoc and independent surveys the decision-supporting ability of the traditional visual examination procedures proves to be inconsiderable, if the subjects of the surveys belong to the same property. Due to several subjective factors the evaluation of these surveys and their comparative analysis are almost impossible. It is supposable that the fuzzy expert system proposed in this article may remedy the problem mentioned above, owing to the peculiarities of this professional field (application of a variety of linguistic variables, uncertainty originated from different sources, assumptions based on experiences and observations). This paper sketches out the facts of uncertainties of the visual examination procedure in building diagnostics, then describes the architecture and components of the fuzzy expert system. Thereafter, the operation of this method is illustrated through three building diagnostics case studies. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2009.5342283

Transportation network realization with an optimization method

Tamás Hartványi András Bakó István Szuts

Publication Name: Isciii 09 4th International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2009-12-28

Volume: Unknown

Issue: Unknown

Page Range: 81-84

Description:

In connection with the network realization problem the main questions of the algorithm are which edges to choose and what is the budget consequence of that. These problems can be solved by exact optimization methods, but in this case the number of computational steps (additions and comparisons) is an exponential function of the number of nodes. For this reason usually heuristic methods are chosen for solving these problems. Some special problems can be formulated as maximal flow problems. To get the solution we use only maximal flow and shortest route algorithms. Thus we decrease the number of computations, but the size of the network will grow. In this paper we describe this algorithm to solve the network realization problem. Then we give a transportation network realization problem and show how to solve this problem by the some algorithms. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2009.5342277

Fuzzy approach to utility of time factor

János Botzheim Peter Foldesi Edit Süle

Publication Name: Isciii 09 4th International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2009-12-28

Volume: Unknown

Issue: Unknown

Page Range: 23-29

Description:

The paper deals with the investigation of the critical factor of the supply chain concerning time factor. The literature review can give a background to understand and handle the reasons and consequences of the growing importance of time. By using utility functions to represent the value of various delivery-times for the different participants in the supply chain, including the final customers, it proves through the Kano-model, that the choices, behaviour and willingness of payment of time-sensitive and non time-sensitive consumers are different for varying lead times, so for optimization soft computing techniques must be applied. As the functions are not linear and significant uncertainty must be handled as well, the use of fuzzy numbers is necessary. The features of fuzzy power functions are investigated, and a parametric approaches is presented that can be an efficient approximation of the values calculated on the basis of extension principle. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2009.5342282

Multilayer perceptrons constructed of fuzzy flip-flops

László Gál Rita Lovassy László T. Kóczy

Publication Name: Isciii 09 4th International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2009-12-28

Volume: Unknown

Issue: Unknown

Page Range: 9-14

Description:

The target of this paper is to propose a hybrid combination of the three main branches of Computational Intelligence, namely Fuzzy Systems, Neural Networks and Evolutionary Computing. The function approximation properties of fuzzy J-K and D flip-flops based feedforward neural network optimized and trained with a novel evolutionary algorithm based technique; the Bacterial Memetic Algorithm with Modified Operator Execution Order (BMAM) is studied. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2009.5342288

New energy management of capacitive energy storage in metro railcar by simulation

I. Szenasy

Publication Name: 5th IEEE Vehicle Power and Propulsion Conference Vppc 09

Publication Date: 2009-12-23

Volume: Unknown

Issue: Unknown

Page Range: 181-187

Description:

This paper focuses on the use of modeling and simulation of a renewable energy. The capacitive energy storages contribute to the rapid energy recovery associated with regenerative braking in electric vehicles. This power system allows the acceleration and deceleration of the vehicle with a lower loss of energy. Short-distance passenger traffic on electrified lines is a domain where brake energy recuperation might reduce the total energy consumption significantly. In this paper the results of simulation models by Matlab-Simulink for an urban-metro railcar and some methods for reducing the needed value of capacitance are presented. The aim of the new management of the energy storage system for decreasing the needed value of capacitance and improving the system performance is presented. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/VPPC.2009.5289852

Motion control and communication of cooperating intelligent robots by fuzzy signatures

Tamás D. Gedeon Áron Ballagi László T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2009-12-10

Volume: Unknown

Issue: Unknown

Page Range: 1073-1078

Description:

This paper presents two examples of usage of fuzzy signatures in the field of mobile robotics. The first shows a complex lateral drift control method base on fuzzy signatures. This method inspects the motion system of the robot as a whole, unlike as simple parts of a complex system. The state space is written down by fuzzy signatures which add up flexibility, adaptability and learning ability to the system. In the second experiment a new communication approach is investigated for intelligent cooperation of autonomous mobile robots. Effective, fast and compact communication is one of the most important cornerstones of a high-end cooperating system. In this paper we propose a fuzzy communication system where the codebooks are built up by fuzzy signatures. We use cooperating autonomous mobile robots to solve some logistic problems. ©2009 IEEE.

Open Access: Yes

DOI: 10.1109/FUZZY.2009.5277207

Computational fluid flow simulation on body fitted mesh geometry with IBM cell broadband engine architecture

Sándor Kocsárdi Zoltán Nagy András Kiss Árpád Csík

Publication Name: Ecctd 2009 European Conference on Circuit Theory and Design Conference Program

Publication Date: 2009-12-10

Volume: Unknown

Issue: Unknown

Page Range: 827-830

Description:

The solutions of partial differential equations (PDEs) play a key role in today's real world simulations. Computational Fluid Dynamics (CFD) is an important part of this area, which involves the problem of gas or fluid flow over different obstacles, e.g., air flow around vehicles, buildings, or the flow of water in the oceans. In engineering applications the temporal evolution of non-ideal, compressible fluids is quite often modeled by the system of Navier-Stokes equations. They are a coupled set of nonlinear hyperbolic partial differential equations and form a relatively simple, yet efficient model of compressible fluid dynamics. In the paper the implementation of a CFD on Body Fitted Mesh geometry on the Cell Broadband Engine is described. An arbitrary surface can be more easily simulated on body fitted mesh than on rectangular computation domain. ©2009 IEEE.

Open Access: Yes

DOI: 10.1109/ECCTD.2009.5275111