Search Everything

Tip: Search using "First Name + Last Name", e.g.
János Kiss instead of Kiss János.

Publications - 6374

Frequency-Band Sensitivity Mapping of Gearbox Housing Concepts Based on Sound Pressure Spectra

Dániel Feszty Krisztián Horváth

Publication Name: Applied Sciences Switzerland

Publication Date: 2026-03-01

Volume: 16

Issue: 6

Page Range: Unknown

Description:

Gearbox housing stiffness strongly influences radiated noise in electric drivetrains, particularly in the absence of engine masking. While high-fidelity vibro-acoustic simulations provide detailed insight, they are computationally demanding for early-stage design screening. This study investigates whether extremely compact spectral descriptors can encode stiffness-related information. The descriptors consist of five 1 kHz band-averaged sound pressure levels between 1 and 6 kHz. These band-averaged quantities are treated as compact spectral descriptors representing the acoustic response of each gearbox housing configuration. The analysis is based on a simulation-derived dataset of twelve spectra representing three ribbing configurations of a single gearbox housing geometry. A Random Forest classifier evaluated using leave-one-out cross-validation (LOOCV) achieved 0.75 accuracy. Confusion matrix analysis indicates clear separation of the flexible concept. Intermediate and rigid configurations show partial spectral overlap. Permutation testing suggests that the observed classification performance exceeds random chance, although uncertainty remains substantial due to the small dataset size. Feature-importance analysis identifies the 2–4 kHz region as the most stiffness-sensitive frequency range, supporting physical interpretations of mid-frequency structural–acoustic coupling. This exploratory study highlights both the potential and the statistical limits of minimal frequency-band descriptors for rapid NVH stiffness screening under small-sample conditions.

Open Access: Yes

DOI: 10.3390/app16063079

Taxonomic analysis of the diversity in the level of wind energy development in european union countries

Laszlo Vasa Tomasz Pisula Mirosław Liana Katarzyna Chudy-Laskowska

Publication Name: Energies

Publication Date: 2020-09-01

Volume: 13

Issue: 17

Page Range: Unknown

Description:

In this paper, the development of the wind energy sector in 28 European Union countries in 2017 is described. By means of taxonomic methods-i.e., Ward's method and the Wroclaw taxonomic methods-clusters of countries similar in terms of their potential and level of development of the wind energy sector in the EU are distinguished. The main purpose of the paper is to separate and cluster EU countries due to the current development potential of the wind energy sector and determinants stimulating the development of this sector. By means of the ranking methods of linear ordering (Technique for Order of Preference by Similarity to Ideal Solution-TOPSIS method), a ranking of EU countries that defines their position in the development of this very important wind energy sector was determined. The results show that the research hypothesis of a great diversity of EU countries considering the development potential of the wind energy sector is justified. The countries of the former European Union, which have focused for a long time on the development of wind energy in their energy policy and have had favorable climate and natural conditions, as well as a large social acceptance of programs supporting the acquisition of energy from renewable sources, have primacy in the development ranking of the energy sector. Additionally, new members of the union, in spite of some delays associated with the development of "green"energy, are trying to increase their energy potential in this area. The research may be extended to include further analyses regarding other renewable energy sources and take into account other European and world countries.

Open Access: Yes

DOI: 10.3390/en13174371

On the set for which 1 is univoque

I. Kátai Gábor Kallos

Publication Name: Publicationes Mathematicae Debrecen

Publication Date: 2001-01-01

Volume: 58

Issue: 4

Page Range: 743-750

Description:

For some integer K ≥ 2 let εK be the set of those ⊖ ∈ (1/K + 1, 1/K ), for which 1 has only one expansion 1 = e1 ⊖ + e2 ⊖2 + . . . with digits ej ∈ {0, . . . , K}, (j =1, 2, . . . ). In this paper we prove, that the Lebesgue measure of the set εK is 0.

Open Access: Yes

DOI: 10.5486/pmd.2001.2436

Robot cooperation by fuzzy signature sets rule base

Áron Ballagi Laszlo T. Koczy

Publication Name: Sami 2010 8th International Symposium on Applied Machine Intelligence and Informatics Proceedings

Publication Date: 2010-04-30

Volume: Unknown

Issue: Unknown

Page Range: 37-42

Description:

This paper presents a novel method for control cooperating robots without any explicit communication line. We have proposed a fuzzy communication philosophy and implementation technique, where the codebooks are built up by signatures. Fuzzy signatures are used as complex state description method for intention guessing and action selection. Finally some real scenarios of autonomous mobile robot cooperation are presented. ©2010 IEEE.

Open Access: Yes

DOI: 10.1109/SAMI.2010.5423703

New Buckling Curve for a Compressed Member with Cold-Formed Channel Cross-Section

B. Vaszilievits-Sömjén F. Papp

Publication Name: Buildings

Publication Date: 2024-10-01

Volume: 14

Issue: 10

Page Range: Unknown

Description:

The verification of a column made from a lipped cold-formed channel section, subjected to pure axial compression relative to the gross cross-section, often results in a combined verification of bending and compression due to the appearance of a shift of the centroid of its effective cross-section. Following Eurocode 3 rules, this requires the determination of two distinct effective cross-sections and various interaction factors. This paper, based on an analytic approach, offers a modification to the actual buckling curve, based on Ayrton–Perry formulation, to include the second-order effects raised by the eventual shift of the effective centroid due to local buckling of the compressed web plate. This eliminates the need to use an interaction formula. The modified buckling curve is verified based on a GMNIA analysis performed on a numerical parametric model, which was previously validated by laboratory tests. In addition, the results are compared with strength results provided by appropriate Eurocode 3 formulas and AISI Direct Strength Method for global-local interaction and with classic experimental results.

Open Access: Yes

DOI: 10.3390/buildings14103258

Effect of emulated head-tracking for reducing localization errors in virtual audio simulation

Gyorgy Wersenyi

Publication Name: IEEE Transactions on Audio Speech and Language Processing

Publication Date: 2009-02-01

Volume: 17

Issue: 2

Page Range: 247-252

Description:

Virtual audio simulation uses head-related transfer function (HRTF) synthesis and headphone playback to create a sound field similar to real-life environments. Localization performance is influenced by parameters such as the recording method and the spatial resolution of the HRTFs, equalization of the measurement chain as well as common headphone playback errors. The most important errors are in-the-head localization and front-back reversals. Among other cues, small movements of the head are considered to be important to avoid these phenomena. This study uses the BEACHTRON sound card and its HRTFs for emulating small head-movements by randomly moving the virtual sound source to emulate head-movements. This method does not need any additional equipment, sensors, or feedback. Fifty untrained subjects participated in the listening tests using different stimuli and presentation speed. A virtual target source was rendered in front of the listener by random movements of 1 -7 . Experiments showed that this kind of simulation can be helpful to resolve in-the-head localization, but there is no clear benefit for resolving front-back errors. Emulation of small head-movements of 2 could actually increase externalization rates in about 21% of the subjects while presentation speed is not significant. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/TASL.2008.2006720

Fuzzy approach for the decision on disposable or returnable packaging

Peter Foldesi Péter Böröcz Kata Vöröskoi Laszlo T. Koczy

Publication Name: Sustainability Switzerland

Publication Date: 2020-09-01

Volume: 12

Issue: 18

Page Range: Unknown

Description:

In modern logistics, companies and packaging engineers have to make decisions to find the optimal sustainable product-packaging system with adequate protection. The decision most often involves a decision option between disposable (single-trip) and reusable (returnable) packaging solutions. In practice, in most cases, this decision is based on historical data and traditions and only considers the packaging material and investment expenses. Although cost is an important factor, it is not the only one needed to find the optimal solution. Several other alternative factors further complicate the situation. Traditional (two-valued) logic is not able to model this problem. This study presents a novel technique to help the decision-making process using the application of fuzzy approach. The authors used three different fuzzy signatures connected by fuzzy rules to model the packaging decisions, which were based on logistics expert opinions. Practical examples are presented concerning both customer packaging (primary packaging) and industrial transport packaging (secondary packaging) as well.

Open Access: Yes

DOI: 10.3390/SU12187304

An Efficient Tour Construction Heuristic for Generating the Candidate Set of the Traveling Salesman Problem with Large Sizes

Peter Foldesi Boldizsar Tuu-Szabo Laszlo T. Koczy

Publication Name: Mathematics

Publication Date: 2024-10-01

Volume: 12

Issue: 19

Page Range: Unknown

Description:

In this paper, we address the challenge of creating candidate sets for large-scale Traveling Salesman Problem (TSP) instances, where choosing a subset of edges is crucial for efficiency. Traditional methods for improving tours, such as local searches and heuristics, depend greatly on the quality of these candidate sets but often struggle in large-scale situations due to insufficient edge coverage or high time complexity. We present a new heuristic based on fuzzy clustering, designed to produce high-quality candidate sets with nearly linear time complexity. Thoroughly tested on benchmark instances, including VLSI and Euclidean types with up to 316,000 nodes, our method consistently outperforms traditional and current leading techniques for large TSPs. Our heuristic’s tours encompass nearly all edges of optimal or best-known solutions, and its candidate sets are significantly smaller than those produced with the POPMUSIC heuristic. This results in faster execution of subsequent improvement methods, such as Helsgaun’s Lin–Kernighan heuristic and evolutionary algorithms. This substantial enhancement in computation time and solution quality establishes our method as a promising approach for effectively solving large-scale TSP instances.

Open Access: Yes

DOI: 10.3390/math12192960

Observation of stacked corrugated paper boxes' motion under vibration simulation

No authors available

Publication Name: 21st IAPRI World Conference on Packaging 2018 - Packaging: Driving a Sustainable Future

Publication Date: 2019-01-01

Volume:

Issue:

Page Range: 160-167

Description:

The unitized loads are the major form of the packed product transportation, and most of the cases the packages are fixed to the pallet with straps, stretch film or these combinations. During transport, various vibrations occur in the packaging-product system, which can damage the products. Many of studies focus on the nature of these vibrations, but the vibration varies between the layers of stacked packaging is not fully researched. This paper focuses on the different motion of the layers in the unitized loads in function of the fixing mode to the pallet. Therefore, multiple unitized loads were built from the same corrugated paper boxes in three layers with various fixing mode, to measure each layer motion during vibration. To carry out the simulation procedure, acceleration on each layer was recorded under sine and random vibration simulation. The recorded data shows, which layer motion is the most disparate from the excited motion, which fixing variant caused this difference.

Open Access: No

DOI: DOI not available