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Publications - 6374

Analysis and test results of quasi-resonant converters

Z. Puklus Peter Korondi Peter Csaba Szilagyi László Hodossy

Publication Name: Telescon 1997 2nd International Telecommunications Energy Special Conference

Publication Date: 1997-01-01

Volume: Unknown

Issue: Unknown

Page Range: 185-190

Description:

This paper presents the test results and simplified design method of a new type symmetrical resonant DC/DC converter. The realised converter operates in the frequency range of 30-300 kHz. This paper contributes the theoretical results of the resonant type DC/DC converters and shows the hits of their usage. The output voltage-current curve (Uo-Io) shows the typical features of the converter operation.

Open Access: Yes

DOI: 10.1109/TELESC.1997.655714

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

Gestural and facial communication with smart phone based robot partner using emotional model

János Botzheim Jinseok Woo Noel Tay Nuo Wi Toru Yamaguchi Naoyuki Kubota

Publication Name: World Automation Congress Proceedings

Publication Date: 2014-10-24

Volume: Unknown

Issue: Unknown

Page Range: 644-649

Description:

When conducting natural communication in addition to perform verbal communication, a robot partner should also understand non-verbal communication such as facial and gestural information. The word 'understand' for the robot means how to grasp the meaning of the gesture itself. In this paper we propose a smart phone based system, where an emotional model connects the facial and gestural communication of a human and a robot partner. The input of the emotional model is based on face classification and gesture recognition from the human side. Based on the emotional model, the output action such as gestural and facial expressions for the robot is calculated.

Open Access: Yes

DOI: 10.1109/WAC.2014.6936076

Resistance to Tensile Stress and Foam Structure Formation in Chemically Foamed rPET Blends †

V. A. Szabó Gábor Böcz Gabor Dogossy

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

This research investigates the correlation between tensile strength, tensile strain, and porosity in chemically foamed recycled poly(ethylene-terephthalate) (rPET) samples. Tensile strength and strain were measured on non-foamed samples to predict the porosity of the foamed samples. Utilizing various flame retardants and additives, we analyzed their impact on mechanical properties and structures. However, neither tensile strength nor strain demonstrated a reliable correlation with the resulting porosity. Strain values did not consistently predict porosity, indicating the significant role of additive types and concentrations.

Open Access: Yes

DOI: 10.3390/engproc2024079070

Time optimal control of ground vehicles

Gyorgy Max Bela Lantos

Publication Name: Sisy 2014 IEEE 12th International Symposium on Intelligent Systems and Informatics Proceedings

Publication Date: 2014-10-14

Volume: Unknown

Issue: Unknown

Page Range: 245-250

Description:

The paper deals with the time optimal control of automatically driven cars modeled with gear shift as discrete control input beside the continuous ones in a test path between corridors. The car is required to avoid a static obstacle or performing double lane change. The problem can be formulated as a mixed-integer optimal control problem (MIOCP). The resulting MIOCP is solved by reformulating it to static mixed-integer nonlinear program (MINLP) using time discretization and direct multiple shooting method. Non-commercial open software packages are applied that substantially use the gradients of the objective function and the Jacobians of the constraints exploiting sparsity. A novel algorithm and implementation is presented for computing the derivatives of the complex state trajectory joining equations. This algorithm was given in the form of matrix differential equations whose structure allowed to compute their solution using RK4 in matrix form. The elaborated method can be applied both for combustion engine and electric driven cars. It can form the basis to generate an offline database of a central general collision avoidance system (CAS) for varying path parameters on a grid which can support real time applications.

Open Access: Yes

DOI: 10.1109/SISY.2014.6923594

Which players will leave their community? Predicting guild abandonments in world of warcraft game data

Gergely Posfai Gabor Magyar Laszlo T. Koczy

Publication Name: Ifsa Scis 2017 Joint 17th World Congress of International Fuzzy Systems Association and 9th International Conference on Soft Computing and Intelligent Systems

Publication Date: 2017-08-30

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

World of Warcraft (WoW) is one of the most popular massively multiplayer online role-playing games (MMORPGs) having more than 10 million subscribers over the world. In order to engage and retain users understanding and predicting their behavior can be very useful for game developers. An important component of WoW are so-called guilds, which are social communities whose members can act together efficiently to accomplish more difficult goals and also provide a social atmosphere in which the game might be more entertaining. In this paper, we build predictive models to forecast which of the players will leave their guild in the close future. Our best model uses fuzzy c-means clustering to capture groups of similar guilds, that serve as the basis of an ensemble model, which computes predictions for each cluster separately and combines individual predictions into one final prediction using the memberships of the fuzzy clusters. Empirical analysis on WoW game data shows that our methods convincingly outperform the only existing method in the literature. To ensure transparency and reproducibility we publish the source codes of the research and also provide a Docker image, which makes it possible for anyone who has Docker installed to reproduce all of our results with a single command.

Open Access: Yes

DOI: 10.1109/IFSA-SCIS.2017.8023234

A bullwhip type of instability induced by time varying target inventory in production chains

Peter Foldesi Árpád Csík

Publication Name: International Journal of Innovative Computing Information and Control

Publication Date: 2012-08-01

Volume: 8

Issue: 8

Page Range: 5885-5897

Description:

We present an analytic investigation of the bullwhip effect developing in production-distribution chains. All common considered causes of the effect are excluded and the only mean to induce a bullwhip type of instability is the adoption of an inventory replenishment policy involving a variable target level. The policy is designed to maintain a safety stock that is proportional to the actual demand. In order to achieve our goals we develop a particular discrete model of supply chains by introducing some fresh concepts into the field of supply chain stability. The basic idea is to derive an update scheme describing the status of the whole chain over the entire time-space (period-stage) domain of interest. We prove that the strategy of demand driven target inventory inherently leads to an instability developing in the chain, which is precisely a manifestation of the bullwhip effect. Following the identification of the source and the nature of the instability, we propose a new production plan, which is stable and does not exhibit the bullwhip effect at all. Thus, the amplitude of the variation of the production rate never exceeds the amplitude of the oscillation of the market demand within the entire supply chain. © 2012 ICIC International.

Open Access: Yes

DOI: DOI not available

Residual elimination algorithm for solving linear equations and application for sparse systems

No authors available

Publication Name: ZAMM Zeitschrift fur Angewandte Mathematik und Mechanik

Publication Date: 1996-12-01

Volume: 76

Issue: SUPPL. 1

Page Range: 485-486

Description:

A new direct algorithm for solving linear system of equations will be presented. Short theoretical background and analysis of the proposed method will be given. We formulate an optimized version of the proposed algorithm, which also works for sparse matrices. The complexity of the suggested algorithm for full matrix systems is n3/3 H- O(n2) where n is the dimension of the problem. The numerical experiments show that some versions of the residual elimination algorithm can be competitive with the Gaussian elimination both in complexity and precision. Moreover the sparse linear solver based on this algorithm has some advantages in parallel environment.

Open Access: No

DOI: DOI not available

Analysis of railway vehicles' bogies with different wheel forces

No authors available

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

Publication Date: 1996-12-01

Volume:

Issue:

Page Range: 203-213

Description:

For the past ten years, geometry and loaded tests on railway bogies are in progress at the Department for Automotive and Railway Engineering of Szechenyi Istvan College. Following analysis of running and driven bogies and laboratory measurements, operating test of running vehicles has also been conducted. Initial results made it possible to perform different theoretical and computer analysis.

Open Access: No

DOI: DOI not available