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Found 6423 publications

A population based metaheuristic for traveling salesman type problems

Péter Földesi Boldizsár Tüu-Szabó Laszlo T. Koczy

Publication Name: 2017 International Conference on Fuzzy Theory and Its Applications Ifuzzy 2017

Publication Date: 2017-03-09

Volume: 2017-November

Issue: Unknown

Page Range: 1-5

Description:

In this paper we present a metaheuristic method, called DBMEA. It combines the bacterial evolutionary algorithm with local search techniques. Based on our test results it can be used for solving efficiently more discrete optimization problems. The algorithm was tested on Traveling Salesman Problem and Traveling Repairman Problem (TRP) benchmark instances found in the literature. In the case of TSP the DBMEA algorithm produced optimal or near-optimal solutions for all tested instances. Although the most efficient TSP solver method, the Helsgaun's Lin-Kernighan heuristic was faster than DBMEA, but in the case of DBMEA the runtime was more predictable than it the case of other methods. In the case of TRP the results are competitive in terms of accuracy and runtimes with the state-of-the art methods. Except two instances our algorithm found the best-known solutions, and for the biggest tested instance it found new best solution. The runtime was on average 30% faster than the most efficient heuristic in the literature.

Open Access: Yes

DOI: 10.1109/iFUZZY.2017.8311797

SENIOR MANAGEMENT MINDSETS FOR CORPORATE SOCIAL RESPONSIBILITY

Loma Mashne Zoltán Baracskai

Publication Name: Management Croatia

Publication Date: 2024-01-01

Volume: 29

Issue: 1

Page Range: 1-17

Description:

Despite the large amount of factual data on senior management’s significant role in achieving corporate social responsibility (CSR), little effort has been devoted to shed light on the CSR decision-making process and the managerial mindsets that drive it. To fill this gap in CSR research, this study explores the CSR decision-making process and senior management mindsets regarding CSR, inductively prompted by the CSR literature and a qualitative study. This study offers a conceptual model of socially responsible decision-making based on the Doctus knowledge-based system. The model is empirically analyzed and verified through semi-structured interviews with CSR experts. Further, an inductive examination of the qualitative data using individual-level analysis revealed three different mindsets of senior management towards CSR: conformist, self-interested, and shareholder satisfaction/profit-driven mindsets.

Open Access: Yes

DOI: 10.30924/mjcmi.29.1.1

Vulnerability Assessment of Levee Failure Due to Underseepage in the Szigetköz Floodplain Area

Edina Koch Richard P. Ray

Publication Name: Water Switzerland

Publication Date: 2026-03-01

Volume: 18

Issue: 5

Page Range: Unknown

Description:

Analysis of the likelihood of structural or hydraulic failures of levees is a crucial part of flood risk assessment and is affected by many uncertainties. This paper evaluates a critical area along the Danube River in the Szigetköz floodplain, where hydraulic risk has been increasing due to rising flood levels. Blanket theory approaches demonstrated the probability of failure relative to erosional failure, and Monte Carlo simulations generated fragility curves. The results of the case study show that the thickness of the aquifer layer has a slight effect if it is deeper than 30 m. The research also reveals that the probability of failure is highly affected by the distance from the river to the riverside levee toe; the shorter this distance, the higher the hydraulic risk. Sensitivity analyses emphasize the effect of variable inhomogeneity; as the leakage factor increases, the probability of failure due to underseepage increases. Comparing coefficients of variation across different floodwater levels showed that at low floodwater levels, a lower coefficient of variation corresponds to a lower probability of failure. In contrast, at higher floodwater levels, the same coefficient produced a higher probability of failure.

Open Access: Yes

DOI: 10.3390/w18050634

Online Communication of Local Governments During COVID-19 Pandemic in Hungary

Boglárka Barsi Márta Nárai Nóra Baranyai Nóra Baranyai

Publication Name: Frontiers in Political Science

Publication Date: 2021-09-29

Volume: 3

Issue: Unknown

Page Range: Unknown

Description:

Local governments had key and prominent roles in tackling the COVID-19 pandemic. Their task was to take short-term measures quickly and to organize protection and care for those in need. The main objective of our paper is to present how local governments communicated with their inhabitants on various online interfaces in this crisis situation. Our analysis covers 54 settlements representing all the different levels of the settlement network from large cities to small villages. We examined the webpages and Facebook pages of local governments and mayors, first during the first wave and then during the second and third waves of the pandemic. Recognizing their responsibility, local governments clearly tried to provide information to the inhabitants as quickly as possible. They considered the online interfaces the most effective, but the online communication had typically been complemented by information published on more traditional channels as well. There were no significant differences in terms of the way and characteristics of communication among the different types of settlements, although local governments of different sizes obviously had to face different challenges in terms of the amount of tasks they had to tackle. The communication process was a very difficult task because of the lack of information and the not-transparent data provision. Even on the Facebook pages especially suitable for this purpose, interactivity rumbled, and in many cases the questions and suggestions of the inhabitants remained unanswered. It is instructive that, with few exceptions, settlements do not place emphasis on surveying local needs and opinions.

Open Access: Yes

DOI: 10.3389/fpos.2021.711170

Tribological Investigation of Base Oil Supplemented with Zirconia Nanoparticles at Various Operating Temperatures †

I. Szabó Márk Marsicki

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

This study examines oil samples with zirconium dioxide (ZrO2) nanoparticles in Group III base oil at different temperatures, revealing the effects of temperature and concentration on the tribological system. The samples contain 0.1% and 1% ZrO2 nanoparticles, tested at 40–120 °C. The friction results showed that the nanoparticles increase the friction absolute integral values at all tested temperatures; however, static friction can be improved by 3–13%. The study demonstrates the wear-resistant effect of ZrO2 nanoparticles. Significant wear reduction can be achieved even at low concentrations; wear volume can be reduced by 21–87% depending on the nanoparticle concentration and operating temperature. Scanning electron microscopy with EDX helped to identify wear types, the processes occurring on the surfaces, and the percentage of nanoparticles on the surface.

Open Access: Yes

DOI: 10.3390/engproc2024079035

Optimal design of a magneto-rheological clutch

Dávid Törocsik P. Horváth

Publication Name: Mechatronics Recent Technological and Scientific Advances

Publication Date: 2011-01-01

Volume: Unknown

Issue: Unknown

Page Range: 89-93

Description:

Appliances using magneto-rheological fluid (MRF) can find application in shock absorbers, brakes and clutches. Until now the spread of MRF clutches was limited by the moderate torque they can transmit. This paper summarizes the factors influencing the torque transmitted. During the design process of a prototype MRF clutch its most important geometric data have been determined by means of simulation of the magnetic circuit.

Open Access: Yes

DOI: 10.1007/978-3-642-23244-2_11

A Systematic Review of Urban Mobility and Preliminary Research of Transportation Trends in West Hungary †

Tímea Vastag Fanni Lőrincz

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

Based on the available statistical data, most employees travel by car, which results in traffic jams, hurts the environment, and increases household expenditures. As a result of this phenomenon, our investigation aimed to present the global trends in urban mobility. It is also considered preliminary research of Hungarian transportation habits and trends by summarizing the standard fees of taxi service, parking, and maintaining a driving license. As our research methodology, we chose a systematic literature search and a summary of the available secondary data to present the main global trends characterizing urban mobility and the standards typical of Hungarian transport. The results enable the expansion of the research and provide an opportunity to learn about consumers’ attitudes at the national level.

Open Access: Yes

DOI: 10.3390/engproc2024079007

Strain Rate Dependence of PLC Effect in AlMg4.5 Alloys †

Dóra Harangozó Imre Czinege

Publication Name: Engineering Proceedings

Publication Date: 2025-01-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

Tensile tests of AlMg4.5 alloy were carried out at six strain rates to study the Portevin–Le Chatelier (PLC) effect. The measured engineering stress–time and engineering stress–engineering strain curves were evaluated by direct peak detection and reference function approximation. The waiting and decay times of the PLC effect, and the related stress jumps and drops, were determined. It was shown that, as a function of strain rate, the quotient of the decay and the waiting time forms a curve with a decreasing slope after an initial rapid rise; the same can be stated about the time derivative of the stress jumps. These relationships are suitable for identifying serrations that vary depending on the strain rate, in full harmony with the stress serration amplitudes observed in the tensile test diagrams.

Open Access: Yes

DOI: 10.3390/engproc2025113025

The Key Role of 3D Printing Technologies in the Further Development of Electrical Machines

Loránd Szabó Denes Fodor

Publication Name: Machines

Publication Date: 2022-05-01

Volume: 10

Issue: 5

Page Range: Unknown

Description:

There is a strong general demand for the permanent improvement of electrical machines. Nowadays, these are at their near maximum potential, and even small further improvements can only be achieved with great effort and high cost. The single solution should be a paradigm shift in their development, by using radically new approaches to topology, materials, and fabrication. Therefore, the application of diverse 3D printing techniques for advanced fabrication in this field is inevitable. Therefore, these new approaches are receiving a great deal of attention among electrical machines designers. In the paper, the possible applications of these new fabrication technologies in the field of electrical machines are surveyed. The focus is set on emphasizing the advancement over the traditional manufacturing approaches.

Open Access: Yes

DOI: 10.3390/machines10050330