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Publications - 6374

Assembly Line Overall Equipment Effectiveness (OEE) Prediction from Human Estimation to Supervised Machine Learning

János Jósvai Péter Dobra

Publication Name: Journal of Manufacturing and Materials Processing

Publication Date: 2022-06-01

Volume: 6

Issue: 3

Page Range: Unknown

Description:

Nowadays, in the domain of production logistics, one of the most complex planning processes is the accurate forecasting of production and assembly efficiency. In industrial companies, Overall Equipment Effectiveness (OEE) is one of the most common used efficiency measures at semi-automatic assembly lines. Proper estimation supports the right use of resources and more accurate and cost-effective delivery to the customers. This paper presents the prediction of OEE by comparing human prediction with one of the techniques of supervised machine learning through a real-life example. In addition to descriptive statistics, takt time-based decision trees are applied and the target-oriented OEE prediction model is presented. This concept takes into account recent data and assembly line targets with different weights. Using the model, the value of OEE can be predicted with an accuracy of within 1% on a weekly basis, four weeks in advance.

Open Access: Yes

DOI: 10.3390/jmmp6030059

Novel Pure-Pursuit Trajectory Following Approaches and their Practical Applications

Csaba Hajdu Erno Horváth Péter Korös

Publication Name: 10th IEEE International Conference on Cognitive Infocommunications Coginfocom 2019 Proceedings

Publication Date: 2019-10-01

Volume: Unknown

Issue: Unknown

Page Range: 597-602

Description:

Pure-pursuit algorithm is a popular trajectory tracking algorithm, widely used in mobile robotics and vehicular control for numerous reasons. The operation is simple and straightforward as it depends only on the kinematic model of the target mechanical system. The algorithm can be tuned by choosing look-Ahead distance of points of the reference trajectory. On the other hand, pure-pursuit suffers from weaknesses highly attributed to improper selection of look-Ahead distance, resulting in poor tracking performance. Recent developments focused on overcoming this drawback by dynamical change of this parameter. In this paper, we propose three enhancements to the original pure-pursuit algorithm, aiming to handle dynamic selection of look-Ahead distance by selecting multiple goals, modifying look-Ahead distance according to the curvatures and adjusting lateral deviation. Our work was motivated by an ongoing autonomous vehicle research at our university.

Open Access: Yes

DOI: 10.1109/CogInfoCom47531.2019.9089927

Modernization of Windows and Doors in Protected Buildings: Possibilities and Their Environmental Impacts

T. Horváth Kitti Karolyfi András Veöreös Dóra Szalai Zsolt Szűrös Rita Rebeka Ördög

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 1051-1056

Description:

During the renovation of protected buildings, strict regulations must be met. Buildings of different ages and protection categories require different structural solutions, including the modernization of windows and doors. In addition to heritage protection aspects, environmental awareness, sustainability, energy efficiency regulations, and the objectives of Fit for 55 and the Green Deal are given a prominent role. The research examines how the different categories of protection appear in Hungary in connection with the replacement of windows and doors and what regulations apply to their renovation. A case study of a historic building examines the effects of the interventions, with particular regard to the reduction of CO2 emissions, with the help of life cycle assessment (LCA) based on a BIM model, using machine and manual calculations. The results show that it is worth staying with the original solid wood material because changing the material – for example, to modern PVC or aluminum triple-layer windows – involves a greater environmental impact. The methodology of the analysis can be used as an analogy for the renovation of other similar buildings and can serve as a basis for issuing different tenders.

Open Access: Yes

DOI: 10.3303/CET24114176

Deep Metacyclic Parameter Search: Non-Convex optimization Based on Evolutionary Computing with a Few Twists

Adam Csapo

Publication Name: 10th IEEE International Conference on Cognitive Infocommunications Coginfocom 2019 Proceedings

Publication Date: 2019-10-01

Volume: Unknown

Issue: Unknown

Page Range: 247-252

Description:

This paper proposes a new framework for non-convex optimization referred to as Metacyclic Parameter Search (MEPS). The framework combines several approaches that are well known from the field of artificial intelligence-namely the iterative update of generations of candidate solutions prevalent in evolutionary computing and particle swarm optimization, as well as metacognitive approaches implementing reward-based improvement such as (deep) reinforcment learning-resulting in a gradient-free approach to non-convex optimization that combines the benefits (and alleviates the mutual shortcomings) of each of these individual approaches. Following an overview of the framework, its workings are demonstrated on three rudimentary examples.

Open Access: Yes

DOI: 10.1109/CogInfoCom47531.2019.9089907

Motivation and organisational culture from the perspective of SME employees – a case study at the time of COVID-19 pandemic

Renata Machova Ladislav Mura Tibor Zsigmond Ferenc Bakó Marcell Kupi

Publication Name: International Journal of Services Economics and Management

Publication Date: 2024-01-15

Volume: 15

Issue: 1

Page Range: 34-50

Description:

The aim of the research is to investigate the relationship between motivation and organisational culture from the viewpont of employees working at SMEs in Slovakia. The study examines all of this during the COVID-19 period, which took a heavy toll on individuals’ social and organisational relationships as well. To investigate this, first the overlaps between the two areas were indentified. When exploring the theoretical part, the authors faced with the problem that the influence of motivation and organisational culture was usually examined together, and not on each other. A questionnaire survey was conducted, to which 581 valuable responses were received. Based on the results, it was proven that the wider the range of motivation tools used, the more positive the employees evaluate the organisational culture. All of this is worth considering for companies that would like to build a suitable organisational culture in their company.

Open Access: Yes

DOI: 10.1504/IJSEM.2024.136058

Planar trivalent polygonal networks constructed from carbon nanotube Y-junctions

Ibolya Zsoldos

Publication Name: Journal of Geometry and Physics

Publication Date: 2011-01-01

Volume: 61

Issue: 1

Page Range: 37-45

Description:

This work is the first step towards proving that general planar polygonal networks can be constructed as patterns of carbon nanotubes. A subset of the planar polygonal networks, namely the trivalent planar networks, are studied. These patterns can be constructed from carbon nanotubes such that every intersection point of the networks is replaced with a carbon nanotube Y-junction. Accordingly the basic task is to show the basic connections of the carbon nanotube Y-junctions. The basic set of connected Y-junctions is defined and models of the structures are shown. Nanorings with two, three or more branches are constructed from two, three or more Y-junctions such that two tubes of every Y-junction are joined to the neighbouring tubes with the third tube being free. Because of the known, exceptional electronic behaviour of carbon nanotubes, combinations of basic elements of planar nanotube networks could motivate new experimental and theoretical works having the goal of finding the basic electronic tools for nanocircuits. © 2010 Elsevier B.V.

Open Access: Yes

DOI: 10.1016/j.geomphys.2010.09.008

Complex Building’s Decision Support Method Based on Fuzzy Signatures †

Adam Bukovics Ferenc Lilik Laszlo T. Koczy

Publication Name: Buildings

Publication Date: 2024-06-01

Volume: 14

Issue: 6

Page Range: Unknown

Description:

In the inner areas of large cities, many residential buildings built at the turn of the 19th and 20th centuries remain standing. The maintenance and renovation of these buildings have emerged as critical priorities over recent decades. E.g., in Budapest during the socialist era, the majority of these buildings were not renovated, and maintenance was largely neglected. In the subsequent 10–15 years following the end of socialism, financial resources for renovations were scarce due to the extensive transfer of properties from state to private ownership. It is only in the last decade or so that renovations have begun to be systematically addressed. Consequently, a significant portion of the building stock is still pending renovation. Given the current economic conditions, sustainable maintenance and necessary conversion are of paramount importance. Unfortunately, few standardized condition assessment methods are implemented in industrial practice, and the literature on this topic is limited. To address these challenges, we have developed an algorithm and model for condition assessment and decision support, which we refer to as the Complex Building’s Decision Support System based on Fuzzy Signatures (CBDF system). Our model employs a fuzzy signature-based approach to account for uncertainties, errors, and potentially missing data that may arise during the assessment process. The primary aim of this model is to equip professionals involved in building condition assessment with a tool that enables them to make consistent and objective decisions while minimizing errors. This paper provides a brief overview of the CBDF system and presents test results from the assessment of a selected structural component of a building, demonstrating the system’s functionality.

Open Access: Yes

DOI: 10.3390/buildings14061630

Types of development paths and the hierarchy of the regional centres of Central and Eastern Europe

Ádám Páthy

Publication Name: Regional Statistics

Publication Date: 2017-01-01

Volume: 7

Issue: 2

Page Range: 124-147

Description:

After the rapid transformation period of the 1990s, determined predominantly by the crisis effects of a radical political-economic transition, the reshaping of the spatial structure and urban networks slowed in the post-socialist countries of Central and Eastern Europe. The spillover effects of the market economy transition are fad-ing, and cannot be generalized. Instead, other factors, such as involvement in global processes and the creation and exploitation of new types of synergies, become the main drivers of the differ-entiation and development in the urban system. This study attempts to explore the framework and specifics of this new environment by exam-ining resources for development in the Eastern and Central European regional centres.

Open Access: Yes

DOI: 10.15196/rs070202

Testing of Lubricants for DIC Tests to Measure the Forming Limit Diagrams of Aluminum Thin Sheet Materials

Szabolcs Fischer Szabolcs Szalai Mykola Sysyn Attila Németh Dmytro Kurhan Hanna Csótár

Publication Name: Infrastructures

Publication Date: 2023-02-01

Volume: 8

Issue: 2

Page Range: Unknown

Description:

We investigated lubricants and thin teflon foils that can be applied in the formability testing of the thin aluminum sheets used in the electronics and automotive industries. For the tests, thirteen different industrial lubricants (oils and greases) (i.e., L1–L13) and two Teflon films (i.e., 0.08 and 0.22 mm thick) were applied. The authors conducted an Erichsen test, and the thickness reduction of the discs was measured first. In forming-limit curve (FLC) tests, it is crucial that the stresses are localized in the central area of the specimen during forming and that biaxial deformation is maintained throughout, if possible. We aimed to achieve and fulfill this task. To perform this measurement, the GOM ARAMIS measuring system was utilized. It is an optical measuring system based on the digital image correlation (DIC) principle, capable of measuring both stresses and displacements in real time. A specific validation method was also developed to qualify the DIC system. We concluded that there was a 5% difference in Erichsen indentation (IE) number diagrams between the best (L12) and worst (L4) cases for the lubricants and oils tested, which is a significant difference for thin plates. We found that this value could be increased and improved by using Teflon discs. Furthermore, the localization of stress maxima, i.e., the centering of cracks in the specimen, could be achieved by combining Teflon discs and L12 lubricant (with appropriate layer order), which significantly aids in the recording of standard FLC diagrams. Using foils is also advantageous because they are readily available, have no expiry date, and are of less environmental concern.

Open Access: Yes

DOI: 10.3390/infrastructures8020032