András Rövid

55884621000

Publications - 23

On modeling and identification of empirical partially intelligible white noise processes

András Rövid P. Várlaki László Palkovics

Publication Name: Asian Journal of Control

Publication Date: 2021-05-01

Volume: 23

Issue: 3

Page Range: 1262-1279

Description:

The paper discusses the identification of the empirical, partially intelligible white noise processes generated by deterministic numerical algorithms. The introduced fuzzy-random complementary approach can identify the inner hidden correlational patterns of the empirical white noise process if the process has a real hidden structure of this kind. We have shown how the characteristics of autocorrelated white noise processes change as the order of autocorrelation increases. Based on this approach, the original empirical white noise process transformed by the autocorrelation operator can be considered to be random data series (randomlikeness), and at the same time, it has function-like characteristics (functionlikeness), as well. We approach the analysis of the mentioned complementarity by modeling the autocorrelation functions of the empirical white noise processes using tensor product (TP) model transformation.

Open Access: Yes

DOI: 10.1002/asjc.2470

Empirical white noise processes and the subjective probabilistic approaches

András Rövid P. Várlaki László Palkovics

Publication Name: Periodica Polytechnica Transportation Engineering

Publication Date: 2019-11-15

Volume: 48

Issue: 1

Page Range: 19-30

Description:

The paper discusses the identification of the empirical white noise processes generated by deterministic numerical algorithms. The introduced fuzzy-random complementary approach can identify the inner hidden correlational patterns of the empirical white noise process if the process has a real hidden structure of this kind. We have shown how the characteristics of auto-correlated white noise processes change as the order of autocorrelation increases. Although in this paper we rely on random number generators to get approximate white noise processes, in our upcoming research we are planning to turn the focus on physical white noise processes in order to validate our hypothesis.

Open Access: Yes

DOI: 10.3311/PPtr.15165

Integral operators in relation to the HOSVD-based canonical form

András Rövid P. Várlaki László Szeidl

Publication Name: Asian Journal of Control

Publication Date: 2015-03-01

Volume: 17

Issue: 2

Page Range: 459-466

Description:

This paper describes the relation of the higher order singular value decomposition (HOSVD) based canonical form to the Hilbert-Schmidt type integral operators. This connection between the canonical form of f(x) and the integral operators determined by function f(x) is important; on the one hand it gives a new aspect for the consideration of LPV models, and on the other hand it allows for the approximation of eigenfunctions and integral operators based on a numerical reconstruction of the canonical form.

Open Access: Yes

DOI: 10.1002/asjc.1017

Data representation in HOSVD-DCT based domain

András Rövid P. Várlaki László Szeidl

Publication Name: Ines 2013 IEEE 17th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2013-12-12

Volume: Unknown

Issue: Unknown

Page Range: 103-106

Description:

The paper describes an approach for data representation and processing in the so called HOSVD-DCT based domain which combines the higher order singular value decomposition (HOSVD) with the discrete cosine transformation (DCT). The key idea is to express the multivariate function by an orthonormal set of one variable specific functions and perform DCT on those components which are less significant from the application point of view in order to ensure finer grained processing. It is advantageous also in case of system identification, where the behaviour of the system can be approximated by blending locally identified models. In this case the proposed method can efficiently be applied. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/INES.2013.6632791

HOSVD-wavelet based framework for multidimensional data approximation

Szabolcs Sergyán András Rövid P. Várlaki László Szeidl

Publication Name: Iccc 2013 IEEE 9th International Conference on Computational Cybernetics Proceedings

Publication Date: 2013-11-07

Volume: Unknown

Issue: Unknown

Page Range: 29-33

Description:

The representation of data plays significant role in many applications, as for instance when performing data compression, feature extraction or enhancement, etc. In this paper we briefly mention some well known data representation forms and propose a new domain based on the so called higher order singular value decomposition (HOSVD) and wavelet transformation. It will be shown how the data can be processed by manipulating its components in this domain. Furthermore, the properties of the components as well as the applicability of the proposed approach in the field of image processing and system identification will be shown. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/ICCCyb.2013.6617625

Numerical reconstruction and compression of thermal image sequences

András Rövid Takeshi Hashimoto László Szeidl

Publication Name: International Conference on Emerging Trends in Engineering and Technology Icetet

Publication Date: 2012-12-01

Volume: Unknown

Issue: Unknown

Page Range: 298-302

Description:

Data compression and enhancement represent an important consideration in many application areas. The transmission bandwidth and storage capacity are often crucial factors. The efficiency of the processing of data in numerous cases strongly depends on the form of data representation. In the present paper a method, based on the so called higher order singular value decomposition and tensor-product transformation, is introduced for multidimensional scaling and compression of thermal images sequences. The proposed approach operates with smooth functions forming an orthonormal basis. Because of the smoothness property of these orthonormal components, the method can advantageously be utilized for the efficient compression of thermal image sequences. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/ICETET.2012.40

Neural-network based modelling approach for loading systems

Gabriella Orbán Tibor Vadvári András Rövid P. Várlaki

Publication Name: International Conference on Emerging Trends in Engineering and Technology Icetet

Publication Date: 2011-12-01

Volume: Unknown

Issue: Unknown

Page Range: 72-76

Description:

As in many fields in modern logistics the system modelling and identification play an important role. By the modelling of complex non-linear systems different model approximation approaches are utilized. The approximation methods of mathematics are widely used in theory and practice for several problems. In the framework of the paper a higher order singular value decomposition (HOSVD) based approximation approach for neural network (NN) model approximation is introduced. The approach will be detailed from the point of view of logistic systems but it may be applicable for other fields, as well. The NNs in this case stand for local models based on which a more complex parameter varying model can numerically be reconstructed and reduced using the HOSVD. © 2011 IEEE.

Open Access: Yes

DOI: 10.1109/ICETET.2011.69

Adapted queueing algorithms for process chains

P. Földesi András Rövid Ágnes Bogárdi-Mészöly

Publication Name: Smart Innovation Systems and Technologies

Publication Date: 2011-12-01

Volume: 10 SIST

Issue: Unknown

Page Range: 65-73

Description:

Process chains are a common modeling paradigm for analysis and optimization of logistic processes, and are intensively used in many practical applications. The ProC/B toolset is a collection of software tools for modeling, analysis, validation and optimization of process chains. The ProC/B models can be translated into queueing networks or Petri nets, which can be solved by effective techniques and algorithms to evaluate performance metrics. The base queueing model with Mean-Value Analysis evaluation algorithm, and their adaptations for modeling thread pool and queue limit have been verified and validated for multi-tier software systems. The goal of our work is to adapt these models and algorithms for process chains to model parallel processes and queue limit. © 2011 Springer-Verlag Berlin Heidelberg.

Open Access: Yes

DOI: 10.1007/978-3-642-22194-1_7

Control model for loading systems using higher order singular value decomposition

Gabriella Orbán András Rövid P. Várlaki

Publication Name: Proceedings 2011 IEEE International Conference on Computer Science and Automation Engineering Csae 2011

Publication Date: 2011-08-25

Volume: 3

Issue: Unknown

Page Range: 754-758

Description:

In this paper we present a method for constructing a control model of loading systems based on higher order singular decomposition (HOSVD) of a tensor. Modern logistics need control systems that are able to develop and improve the material and information flow by automating the control processes. We propose the application of linear parameter varying (LPV) structure by which non-linear systems can be controlled on the basis of linear control theories. Describing the system, modeling logistic processes require many uncertain input parameters. Using the proposed method the complexity of the model can be kept on a lower level. © 2011 IEEE.

Open Access: Yes

DOI: 10.1109/CSAE.2011.5952783

On tensor-product model based representation of neural networks

András Rövid P. Várlaki László Szeidl

Publication Name: Ines 2011 15th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2011-08-22

Volume: Unknown

Issue: Unknown

Page Range: 69-72

Description:

The approximation methods of mathematics are widely used in theory and practice for several problems. In the framework of the paper a novel tensor-product based approach for representation of neural networks (NNs) is proposed. The NNs in this case stand for local models based on which a more complex parameter varying model can numerically be reconstructed and reduced using the higher order singular value decomposition (HOSVD). The HOSVD as well as the tensor-product based representation of NNs will be discussed in detail. © 2011 IEEE.

Open Access: Yes

DOI: 10.1109/INES.2011.5954721

HOSVD based data representation and LPV model complexity reduction

András Rövid P. Várlaki László Szeidl

Publication Name: Applications of Mathematics and Computer Engineering American Conference on Applied Mathematics American Math 11 5th Wseas International Conference on Computer Engineering and Applications CEA 11

Publication Date: 2011-06-17

Volume: Unknown

Issue: Unknown

Page Range: 164-169

Description:

In the framework of the paper a HOSVD-based approach is introduced for LPV model reduction and multidimensional data representation. By these approaches in case of model reduction the system matrix is expressed with the help of a so called core tensor and a system of specially determined polylinear orthonormal functions. Similar approach will be applied also in case of data representation. The paper gives a detailed description on how to determine the polylinear functions and the core tensor and how the model can be expressed and reduced with their help. Furthermore, the HOSVD-based domain proposed for data representation will be compared to the well known frequency domain - related to Fourier transformation - from the point of view of their common application possibilities and their effectiveness.

Open Access: Yes

DOI: DOI not available

HOSVD based image processing techniques

Szabolcs Sergyán András Rövid László Szeidl I. J. Rudas

Publication Name: Recent Researches in Artificial Intelligence Knowledge Engineering and Data Bases 10th Wseas International Conference on Artificial Intelligence Knowledge Engineering and Data Bases Aiked 11

Publication Date: 2011-06-17

Volume: Unknown

Issue: Unknown

Page Range: 297-302

Description:

In the framework of the paper an improved method for image resolution enhancement is introduced. The enhancement is performed through another representation domain, where the image function is expressed with the help of polylinear functions on higher order singular value decomposition (HOSVD) basis. The paper gives a detailed description on how to determine the polylinear functions corresponding to an image and how to process them in order to obtain a higher resolution image. Furthermore, the proposed approach and the Fourier-based approach will be compared from the point of view of their effectiveness.

Open Access: Yes

DOI: DOI not available

Application of LPV type force model in vehicle crash dynamics

István Harmati András Rövid P. Várlaki

Publication Name: Proceedings of the 9th Wseas International Conference on Applications of Computer Engineering Ace 10

Publication Date: 2010-12-01

Volume: Unknown

Issue: Unknown

Page Range: 174-179

Description:

In the research field of vehicle crash mechanics one of the most important task is finding a model for the deformational force, which gives acceptable approximation, but doesn't need perfect knowledge about the parameters of the vehicle. The FEM based methods, which are applied in the engineering practice give good approximations, but they have extremely large computational complexity and need a large amount of data. On the other hand there exist simple force models, but they not approximate well in details the force-deflection curve. In this paper we introduce a force model for vehicle deformation based on the LPV-HOSVD paradigm, which well approximates the force during the deformational process and has acceptable complexity.

Open Access: Yes

DOI: DOI not available

Approximation of force and energy in vehicle crash using LPV type description

István Harmati András Rövid P. Várlaki

Publication Name: Wseas Transactions on Systems

Publication Date: 2010-07-01

Volume: 9

Issue: 7

Page Range: 734-743

Description:

In accident analysis, vehicle crash mechanics and vehicle safety research modeling of the deformational force and absorbed energy plays a crucial role. The usually applied FEM based methods give good approximations, but they have extremely large computational complexity and require a detailed knowledge about the parameteres of the crash and the vehicle. There are simpler models, but they not give satisfactory approximation. In this paper using the LPV-HOSVD paradigm we introduce a model for vehicle deformation process, which well approximates the deformation force and the absorbed energy, moreover it has acceptable computational complexity.

Open Access: Yes

DOI: DOI not available

LPV type model of deformational force in vehicle collisions

István Harmati András Rövid P. Várlaki

Publication Name: Iccc 2009 IEEE 7th International Conference on Computational Cybernetics

Publication Date: 2009-12-01

Volume: Unknown

Issue: Unknown

Page Range: 103-108

Description:

Modeling of the deformational force and absorbed energy plays a very important role in different fields of vehicle engineering. The usually applied FEM based methods give good approximations, but they have extremely large computational complexity. On the other hand there exist simple force models, but they not approximate well in details the real data. The aim of this paper is to introduce a force model for vehicle deformation, which is able to describe the real process and have acceptable complexity. ©2009IEEE.

Open Access: Yes

DOI: 10.1109/ICCCYB.2009.5393952

Energy distribution modeling of car body deformation using LPV representations and fuzzy reasoning

István Harmati András Rövid P. Várlaki László Szeidl

Publication Name: Wseas Transactions on Systems

Publication Date: 2008-12-01

Volume: 7

Issue: 11

Page Range: 1228-1237

Description:

The main aim of the paper is to introduce a novel method - based on fuzzy control and linear parameter varying (LPV) system representation transformable into HOSVD based Canonical form - for modeling deformation processes with respect to the distribution of the absorbed kinetic energy. Modeling such kind of processes requires many uncertain input parameters. Using the proposed concept we are able to handle them and keep the complexity of the models low by using higher order singular value decomposition (HOSVD) technique.

Open Access: Yes

DOI: DOI not available

Energy absorption modelling technique for car body deformation

István Harmati András Rövid P. Várlaki

Publication Name: Saci 2007 4th International Symposium on Applied Computational Intelligence and Informatics Proceedings

Publication Date: 2007-10-01

Volume: Unknown

Issue: Unknown

Page Range: 269-272

Description:

The main object of this paper is to introduce a model for describing how the enrgy distribution changes during deformational processes, esp. in car crashes. This an important and difficult task in accident analysis and in safety car-body design. Exact estimation or measuring of the absorbed energy by the deformation is almost impossible. The classical tool for this task is usually a differental equation based finite element method, which requires exact knowledge about the parameters and takes a lot of computational time with high complexity. In the following we introduce a simple numerical model for the changing of the energy distribution during the whole deformational process. © 2007 IEEE.

Open Access: Yes

DOI: 10.1109/SACI.2007.375523

Application of tensor product models for vehicle de-formational processes

Istvan Harmati András Rövid P. Várlaki

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

Publication Date: 2006-12-01

Volume: Unknown

Issue: Unknown

Page Range: 615-620

Description:

Modelling of vehicle deformational processes plays an important role in car body design and accident analysis. It is a difficult task and usually carried out applying a kind of finite element method. Determination of the absorbed energy by the deformation and the corresponding energy equivalent speed (EES) can be of great importance. Exact determination or measuring of these quantities is almost impossible, so one could estimate them. In this paper we introduce a modeling technique and a model for describing the deformation process. A short description of the main idea: let we have a 3-dimensional rectangular grid on the vehicle body (or on something else). The partition is determined by taking into consideration the energy absorbing properties of the parts of the vehicle, so each cell is approximately homogenous. The cells could be identified as the entries of a tensor of order 3. We concentrate on the energy absorbed by the cells, but not on the physical coordinates of the cells. Energy absorption property (rate of the input and the absorbed energy) of a certain cell could change during the deformational process, so the absorbed energy is calculated using a monotonous decreasing function. These functions can be defined for each possible orthogonal direction of the possible impact. Instead of the original impact we deal with its orthogonal components and the result will be the sum of the particular results. The rectangular grid allows us to compute from level to level. These computations can be realized applying tensor products, the model has low complexity which can be more decreased by complexity reducing methods known from linear algebra.

Open Access: Yes

DOI: DOI not available

Identification and reconstruction of car body deformation applying tensor product models

István Harmati András Rövid P. Várlaki László Szeidl

Publication Name: Ines 2006 10th International Conference on Intelligent Engineering Systems 2006

Publication Date: 2006-12-01

Volume: Unknown

Issue: Unknown

Page Range: 98-101

Description:

Car body deformation modeling plays a very important role in crash accident analyses, as well as in safe car body design. The determination of the energy absorbed by the deformation and the corresponding Energy Equivalent Speed can be of key importance, however their precise determination is a very difficult task. Although, using the results of crash tests, intelligent and soft methods offer an automatic way to model the crash process itself, as well as to determine the absorbed energy, the before-crash speed of the car, etc. In this paper a modeling technique and an intelligent expert system are introduced which together are able to follow the deformation process of car bodies in car crashes and to analyze the strength of the different parts without any human intervention thus significantly can contribute to the improvement of the modeling, (automatic) design, and safety of car bodies. © 2006 IEEE.

Open Access: Yes

DOI: DOI not available

Fuzzy Based Brightness Compensation for High Dynamic Range Images

András Rövid P. Várlaki A. R. Várkonyi-Kóczy

Publication Name: Journal of Advanced Computational Intelligence and Intelligent Informatics

Publication Date: 2006-07-01

Volume: 10

Issue: 4

Page Range: 549-554

Description:

High dynamic range of illumination may cause serious distortions and other problems in viewing and further processing of digital images. In this paper a new fuzzy based tone reproduction pre-processing algorithm is introduced which may help in developing hardly or nonviewable features and content of the images making easier the further processing of it.

Open Access: Yes

DOI: 10.20965/jaciii.2006.p0549

Fuzzy based brightness compensation for high dynamic range images

András Rövid P. Várlaki A. R. Várkonyi-Kóczy

Publication Name: Ines 05 IEEE 9th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2005-01-01

Volume: 2005

Issue: Unknown

Page Range: 245-248

Description:

The high dynamic range of illumination may cause serious distortions and problems in the view and further processing of digital images. In this paper a new fuzzy based tone reproduction pre-processing algorithm is introduced which may help in developing the hardly or non viewable features and content of the images making easier the further processing of it. © 2005 IEEE.

Open Access: Yes

DOI: 10.1109/INES.2005.1555166

3D model estimation from multiple images

András Rövid P. Várlaki A. R. Várkonyi-Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2004-12-01

Volume: 3

Issue: Unknown

Page Range: 1661-1666

Description:

3D reconstruction plays a very important role in computer vision. The determination of the 3D model from multiple images is of key importance. In this paper a 3D reconstruction algorithm is introduced, which is capable to determine the 3D model without any external intervention.

Open Access: Yes

DOI: 10.1109/FUZZY.2004.1375430

Soft computing based car body deformation and EES determination for car crash analysis systems

András Rövid Pál Michelberger P. Várlaki A. R. Várkonyi-Kóczy Maria Da Graça Ruano

Publication Name: Conference Record IEEE Instrumentation and Measurement Technology Conference

Publication Date: 2004-10-08

Volume: 3

Issue: Unknown

Page Range: 1674-1679

Description:

Car body deformation modeling plays a very important role in crash accident analyses, as well as in safe car body design. The determination of the energy absorbed by the deformation and the corresponding Energy Equivalent Speed can be of key importance, however their precise determination is a very difficult task. Although, using the results of crash tests, intelligent and soft methods offer a way to model the crash process itself, as well as to determine the absorbed energy, the before-crash speed of the car, etc. In this paper a modeling technique and an intelligent expert system are introduced which together are able to follow the deformation process of car bodies in car crashes and to analyze the strength of the different parts, thus significantly can contribute to the improvement of the safety of car bodies.

Open Access: Yes

DOI: DOI not available