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Publications - 6525

On Preservation of Positivity in Some Finite Element Methods for the Heat Equation

Panagiotis Chatzipantelidis Vidar Thomée Zoltán Horváth

Publication Name: Computational Methods in Applied Mathematics

Publication Date: 2015-10-01

Volume: 15

Issue: 4

Page Range: 417-437

Description:

We consider the initial boundary value problem for the homogeneous heat equation, with homogeneous Dirichlet boundary conditions. By the maximum principle the solution is nonnegative for positive time if the initial data are nonnegative. We complement in a number of ways earlier studies of the possible extension of this fact to spatially semidiscrete and fully discrete piecewise linear finite element discretizations, based on the standard Galerkin method, the lumped mass method, and the finite volume element method. We also provide numerical examples that illustrate our findings.

Open Access: Yes

DOI: 10.1515/cmam-2015-0018

Data-driven linear parameter-varying modelling of the steering dynamics of an autonomous car

Gábor Rödönyi R. Toth Péter Kőrös Dániel Pup Ádám Kisari Zsombor Vigh József Bokor

Publication Name: IFAC Papersonline

Publication Date: 2021-07-01

Volume: 54

Issue: 8

Page Range: 20-26

Description:

Developing automatic driving solutions and driver support systems requires accurate vehicle specific models to describe and predict the associated motion dynamics of the vehicle. Despite of the mature understanding of ideal vehicle dynamics, which are inherently nonlinear, modern cars are equipped with a wide array of digital and mechatronic components that are difficult to model. Furthermore, due to manufacturing, each car has its personal motion characteristics which change over time. Hence, it is important to develop data-driven modelling methods that are capable to capture from data all relevant aspects of vehicle dynamics in a model that is directly utilisable for control. In this paper, we show how Linear Parameter-Varying (LPV) modelling and system identification can be applied to reliably capture personalised model of the steering system of an autonomous car based on measured data. Compared to other nonlinear identification techniques, the obtained LPV model is directly utilisable for powerful controller synthesis methods of the LPV framework.

Open Access: Yes

DOI: 10.1016/j.ifacol.2021.08.575

Leveraging the Internet of Things and blockchain technology in Supply Chain Management

Horst Treiblmaier John G. Keogh Abderahman Rejeb

Publication Name: Future Internet

Publication Date: 2019-07-01

Volume: 11

Issue: 7

Page Range: Unknown

Description:

Modern supply chains have evolved into highly complex value networks and turned into a vital source of competitive advantage. However, it has become increasingly challenging to verify the source of raw materials and maintain visibility of products and merchandise while they are moving through the value chain network. The application of the Internet of Things (IoT) can help companies to observe, track, and monitor products, activities, and processes within their respective value chain networks. Other applications of IoT include product monitoring to optimize operations in warehousing, manufacturing, and transportation. In combination with IoT, Blockchain technology can enable a broad range of different application scenarios to enhance value chain transparency and to increase B2B trust. When combined, IoT and Blockchain technology have the potential to increase the effectiveness and efficiency of modern supply chains. The contribution of this paper is twofold. First, we illustrate how the deployment of Blockchain technology in combination with IoT infrastructure can streamline and benefit modern supply chains and enhance value chain networks. Second, we derive six research propositions outlining how Blockchain technology can impact key features of the IoT (i.e., scalability, security, immutability and auditing, information flows, traceability and interoperability, quality) and thus lay the foundation for future research projects.

Open Access: Yes

DOI: 10.3390/fi11070161

Data-Driven Pavement Performance: Machine Learning-Based Predictive Models

Nurullah Bektaş Mohammad Fahad

Publication Name: Applied Sciences Switzerland

Publication Date: 2025-04-01

Volume: 15

Issue: 7

Page Range: Unknown

Description:

Featured Application: This research provides effective methodology for pavement performance predictions using the data obtained from finite element analysis and merging it with machine learning algorithms. Traditional methods for predicting pavement performance rely on complex finite element modelling and empirical equations, which are computationally expensive and time-consuming. However, machine learning models offer a time-efficient solution for predicting pavement performance. This study utilizes a range of machine learning algorithms, including linear regression, decision tree, random forest, gradient boosting, K-nearest neighbour, Support Vector Regression, LightGBM and CatBoost, to analyse their effectiveness in predicting pavement performance. The input variables include axle load, truck load, traffic speed, lateral wander modes, asphalt layer thickness, traffic lane width and tire types, while the output variables consist of number of passes to fatigue damage, number of passes to rutting damage, fatigue life reduction in number of years and rut depth at 1.3 million passes. A k-fold cross-validation technique was employed to optimize hyperparameters. Results indicate that LightGBM and CatBoost outperform other models, achieving the lowest mean squared error and highest R² values. In contrast, linear regression and KNN demonstrated the lowest performance, with MSE values up to 188% higher than CatBoost. This study concludes that integrating machine learning with finite element analysis provides further improvements in pavement performance predictions.

Open Access: Yes

DOI: 10.3390/app15073889

Analyzing the Potential Impacts of the Speed Compliance Behavior of Autonomous Vehicles †

Richárd Horváth Balázs Horváth Attila Borsos Viktor Nagy

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

Many researchers argue that autonomous vehicles (AV) will create a safer and more efficient transport infrastructure. However, some studies have drawn attention to potential problems in relation to how AVs and human-driven vehicles will co-exist. We investigated the effect of speed compliance behavior of AVs on an urban two-lane road section with alternating speed limits of 50 and 30 km/h. A Vissim microsimulation model was used where we gradually increased the traffic volume and the market penetration rate (MPR) of AVs. We found that under low traffic flow conditions the increase in MPR will lead to a decrease in the average speed and worsening of the average travel time. Under medium and, specifically, under saturated conditions, a high share of AVs can bring stability to the system. They can also significantly improve the speed compliance rate.

Open Access: Yes

DOI: 10.3390/engproc2024079063

Examining the Environmental Ramifications of Asbestos Fiber Movement Through the Water–Soil Continuum: A Review

András Torma Gergely Zoltán Macher Dóra Beke

Publication Name: International Journal of Environmental Research and Public Health

Publication Date: 2025-04-01

Volume: 22

Issue: 4

Page Range: Unknown

Description:

The environmental pollution potential of asbestos products is a worldwide health issue, but their dissemination through the water–soil continuum is often an overlooked aspect. Similarly, the behavior of asbestos fibers released from the products is still not fully understood, although our knowledge is based on studies concerning their mineralogical characteristics, health effects, and waste disposal. It has been claimed and contradicted that asbestos harm is only found in air and humans. Asbestos fibers are found not only in industrial settings but also through the industrial use of asbestos cement products, which has contributed to asbestos emissions and its movement in water and soil. Asbestos fibers are diverse in their physicochemical properties, and this diversity has a significant influence on their behavior in the environment. Recent research has confirmed that asbestos can be transported by water and spread to other parts of the environment. However, the mechanisms underlying this, such as the settling of fibers, their attachment to soil particles, or their movement in groundwater, as well as the environmental and health implications, require further investigation. This paper examines the process and impact of asbestos contamination in the interconnected water, soil, and plant environmental sectors, providing a systematic review of the latest literature.

Open Access: Yes

DOI: 10.3390/ijerph22040505

A holistic approach to Sustainable Development Goal 8: Integrating economic growth, employment, and sustainability

Prema Nedungadi Raghu Raman Deepak Kumar Behera Sangeetha Gunasekar Sougata Ray Dávid Lóránt Dénes

Publication Name: Equilibrium Quarterly Journal of Economics and Economic Policy

Publication Date: 2025-03-30

Volume: 20

Issue: 1

Page Range: 147-202

Description:

Research background:The realization of United Nations Sustainable Development Goals (SDGs) 8 hinges on the sustained growth of both the economy and the global employment outlook. In order to ensure progress in fostering inclusive and equitable growth and employment opportunities, it is essential to undertake a comprehensive analysis of the SDG findings across all relevant subtargets. Purpose of the article: This study provides an in-depth analysis of the research surrounding SDG 8 (Decent Work and Economic Growth), emphasizing its pivotal role in sustainable development. Methods: Utilizing the PRISMA framework and BERTopic method, it explores the intricate interconnections between SDG 8 and other goals, such as reducing inequalities (SDG 10), clean energy (SDG 7), climate action (SDG 13), poverty alleviation (SDG 1), and innovation and infrastructure (SDG 9). Findings & value added: The findings emphasize the importance of subtarget 8.1 (sustained per capita growth) and subtarget 8.5 (full employment and decent work for all). Additionally, the study underscores the need for policies supporting resource efficiency and sustainable consumption (subtarget 8.4), while green innovation and the digital economy are strongly linked to subtarget 8.2 (enhanced productivity through technological upgrading). Ensuring that economic growth is inclusive and equitable, as outlined in subtarget 8.3, is crucial for reducing inequalities. Policymakers must balance economic growth with environmental sustainability, promoting decent work conditions (subtarget 8.8) and adopting green technologies. These findings offer valuable insights for advancing SDG 8, ensuring that economic progress benefits all segments of society while safeguarding natural resources and fostering long-term prosperity.

Open Access: Yes

DOI: 10.24136/eq.3342

Examining cross‐border cultural tourism as an indicator of territorial integration across the slovak–hungarian border

Hardi Tamás Eszter Szemerédi Gyula Ocskay Marcell Kupi

Publication Name: Sustainability Switzerland

Publication Date: 2021-07-01

Volume: 13

Issue: 13

Page Range: Unknown

Description:

There are numerous examples of cross‐border regions in Europe, which are regions not properly demarcated by national borders. One of the main driving forces of the European Union is to turn the dividing borders into connecting borders by strengthening the cohesion between states and regions, thus, encouraging regions to remedy the existing ethnic and cultural fragmentation by increasing the intensity and number of cross‐border contacts. Our research focuses on proving that, in symbolic places, such as the cross‐border area of Komárom and Komárno, the cultural values, monuments, and heritage sites are the strongest attraction factors for nationality‐based cultural tourism. To support our hypothesis, we conducted an empirical survey within the framework of the H2020 SPOT (Social and Innovative Platform on Cultural Tourism and its potential towards deepening Europeanisation) in the cross‐border region of Komárom and Komárno. The evaluation con-centrated on four aspects of cultural tourism: the nature of cultural tourism in the area, the resident and visitor perceptions of the cultural tourism offerings, opportunities to increase cross‐border col-laboration, and options to improve the cultural tourism offerings of the area. Our results show that, although there is a great potential in the cross‐border tourist destination of Komárom–Komárno, the integration of the (once united) two towns is advancing very slowly, which can be witnessed in the weaknesses of tourism integration as well.

Open Access: Yes

DOI: 10.3390/su13137225

Matrix factorization and neighbor based algorithms for the netflix prize problem

Bottyan Nemeth Istvan Pilaszy Gabor Takacs Domonkos Tikk

Publication Name: Recsys 08 Proceedings of the 2008 ACM Conference on Recommender Systems

Publication Date: 2008-12-01

Volume: Unknown

Issue: Unknown

Page Range: 267-274

Description:

Collaborative filtering (CF) approaches proved to be effective for recommender systems in predicting user preferences in item selection using known user ratings of items. This subfield of machine learning has gained a lot of popularity with the Netix Prize competition started in October 2006. Two major approaches for this problem are matrix factorization (MF) and the neighbor based approach (NB). In this work, we propose various variants of MF and NB that can boost the performance of the usual ensemble based scheme. First, we investigate various regularization scenarios for MF. Second, we introduce two NB methods: one is based on correlation coeficients and the other on linear least squares. At the experimentation part, we show that the proposed approaches compare favorably with existing ones in terms of prediction accuracy and/or required training time. We present results of blending the proposed methods. © 2008 ACM.

Open Access: Yes

DOI: 10.1145/1454008.1454049