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Found 6515 publications

Mathematical Modeling of the Rail Track Superstructure–Subgrade System

Szabolcs Fischer Dmytro Kurhan Vladyslav Khmelevskyi

Publication Name: Geotechnics

Publication Date: 2025-03-01

Volume: 5

Issue: 1

Page Range: Unknown

Description:

The “rail track superstructure–subgrade” system is a sophisticated engineering structure critical in ensuring safe and efficient train operations. Its analysis and design rely on mathematical modeling to capture the interactions between system components and the effects of both static and dynamic loads. This paper offers a detailed review of contemporary modeling approaches, including discrete, continuous, and hybrid models. The research’s key contribution is a thorough comparison of five primary methodologies: (i) quasi-static analytical calculations, (ii) multibody dynamics (MBD) models, (iii and iv) static and dynamic finite element method (FEM) models, and (v) wave propagation-based models. Future research directions could focus on developing hybrid models that integrate MBD and FEM to enhance moving load predictions, leveraging machine learning for parameter calibration using experimental data, investigating the nonlinear and rheological behavior of ballast and subgrade in long-term deformation, and applying wave propagation techniques to model vibration transmission and evaluate its impact on infrastructure.

Open Access: Yes

DOI: 10.3390/geotechnics5010020

Performance study of domain decomposition methods for 2D parallel finite element analysis

Miklós Kuczmann D. Marcsa

Publication Name: Pollack Periodica

Publication Date: 2013-12-01

Volume: 8

Issue: 3

Page Range: 47-58

Description:

The aim of this paper is to give a unified comparison of non-overlapping domain decomposition methods for solving magnetic field problems. The methods under investigation are the Schur complement method and the Lagrange multiplier based finite element tearing and interconnecting method, and their solvers. The performance of these methods has been investigated in detail for two-dimensional magnetic field problems as case studies.

Open Access: Yes

DOI: 10.1556/Pollack.8.2013.3.5

An overview of research trends in CogInfoCom

Ádam Csapó Péter Várlaki Peter Baranyi

Publication Name: Ines 2014 IEEE 18th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2014-09-24

Volume: Unknown

Issue: Unknown

Page Range: 181-186

Description:

Cognitive infocommunications (CogInfoCom) is an interdisciplinary field that targets engineering applications based on emergent synergies between ICT and the cognitive sciences. The unique perspective of CogInfoCom enables researchers to focus on both the qualitative and quantitative analysis of cognitive capabilities in application areas where humans are becoming increasingly entangled with and dependent on intelligent networked services. An international conference on the field has been held every year since 2010, and the two most recent events have been supported by the IEEE. In this paper, we provide an overview of the various research directions which have been represented at the conference series, and which have as a result gained strong relevance to CogInfoCom during the past few years.

Open Access: Yes

DOI: 10.1109/INES.2014.6909365

Environmental activities of agricultural enterprises: Accounting and analytical support

Laszlo Vasa Nataliya Zdyrko Inna Lepetan Olesya Tomchuk

Publication Name: Economic Annals Xxi

Publication Date: 2018-07-19

Volume: 169

Issue: 1-2

Page Range: 77-83

Description:

The article outlines the causes of the ecological crisis in Ukraine and various factors affecting the natural environment, such as air pollution, depletion and degradation of land resources, exhaustion of forest and water resources, caused by agricultural production. Thus, in Ukraine, as of 1 January 2018, more than 1.1 million hectares of degraded, unproductive and technogenically contaminated lands counted to expand, and there were 315.6 thousand hectares of unproductive lands that needed improvement; 57% of the territory of the country was affected by wind and water erosion, about 12% were flooded lands and 20% more - polluted lands. The authors detail the consequences of the impact of agricultural activities on the environment. It is necessary to reflect environmental activities in accounting, including environmental assets (natural resource potential, production waste, non-current assets of environmental protection purposes), liabilities (environmental liabilities) and results of activities (environmental incomes, environmental expenses, financial results from environmental activities). The components of natural resource potential, which are to be reflected in the accounting system, are determined. The authors of the research provide an analytical estimation of the state, structure and changes of land resources in Ukraine and define the degree of compatibility between the modern system of agriculture and new environmental and technological requirements. The article discusses normative and legal provisions concerning land protection in Ukraine, as well as normative legal acts on ecologisation of agriculture. The tendency of the recent years shows that the mechanism of combining measures of financial incentives and legal responsibility in the field of land protection, as well as the establishment of legally determined environmental restrictions in land use by means of land management, remains insufficient in terms of optimising the use and protection of land in Ukraine. The study covers the main problem aspects of the land use in Ukraine. Analytical data describing the anti-desertification measures planned until 2030, as well as measures for the restoration of degraded lands and soils, including lands affected by desertification, droughts and floods, are presented. The need to reflect the costs of implementing measures to protect and restore the natural resource potential (including land resources) is emphasised. The authors generalise the information on three groups of accounting objects in terms of the use of agricultural land: objects affecting the qualitative condition (natural fertility) of land, objects representing land capital with a certain level of natural fertility which are at the disposal of enterprises, and objects that depend on the type of agricultural lands and their natural fertility. It is suggested to generalise the information on the objects of ecological accounting in the form of the Environmental Activity Report, which will increase the effectiveness of the managerial decisions on the environment at micro- and macro-levels.

Open Access: Yes

DOI: 10.21003/ea.V169-15

New effective MILP models for PFSPs arising from real applications

Tamás Hajba Zoltán Horváth

Publication Name: Central European Journal of Operations Research

Publication Date: 2013-12-01

Volume: 21

Issue: 4

Page Range: 729-744

Description:

Permutation flow shop problems (PFSPs) with makespan minimization that model production lines working in industry often have some special features: they are typically large-scale and the jobs can be sorted into types so that jobs of the same type have equal processing time values at each machine. We define the related R-PFSP, the Permutation with Repetition Flow Shop Problem, which is of less complexity if the number of types is bounded. Moreover, a subproblem set of R-PFSPs, the RL-PFSP is considered too, where only those permutations are in the design space in which subsequent tuples of a certain size contain jobs of the same type. We construct adequate new MILP models for R-PFSPs and RL-PFSPs and investigate their effectiveness experimentally. We demonstrate that via our new MILP models significantly larger problems can be solved than via the classical MILP models. © 2012 Springer-Verlag.

Open Access: Yes

DOI: 10.1007/s10100-012-0263-6

Dataflow-based heterogeneous code generator for IoT applications

Endri Bezati Nebojša Taušan Gábor Paller Gábor Élo Gábor Farkas

Publication Name: Modelsward 2019 Proceedings of the 7th International Conference on Model Driven Engineering and Software Development

Publication Date: 2019-01-01

Volume: Unknown

Issue: Unknown

Page Range: 428-434

Description:

The latest wave of connected digital systems, nowadays called Internet of Things (IoT) promises various gains, especially in terms of significant ease of data access. A large number of different platforms for IoT applications, however, makes their development difficult and time-consuming leading to projects that are failed to be on time, on budget or fully completed. To address the platform heterogeneity, this paper presents the ongoing work on development environment called Orcc-IoT. Orcc-IoT facilitates the development of IoT by combining dataflow modelling language, heterogeneous code generator and the library of ready-made IoT actors. The utilisation of Orcc-IoT in development is expected to increase the quality, and to reduce the development costs and time-to-market of IoT applications.

Open Access: Yes

DOI: 10.5220/0007496804280434

Land subsidence modeling and mapping in Darab region, Iran

Mahrooz Rezaei Narges Kariminejad Vahid Shafaie Monireh Mina Mohammad Reza Loveimi Michel J.P.M. Riksen

Publication Name: Advanced Tools for Studying Soil Erosion Processes Erosion Modelling Soil Redistribution Rates Advanced Analysis and Artificial Intelligence

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 275-294

Description:

Land subsidence refers to the collapse of Earth's surface. This study aimed to model land subsidence using machine learning methods in the Darab region of Fars Province, which is recognized as one of the most critical provinces suffering from land subsidence in the country. Nineteen factors affecting the occurrence of land subsidence were selected as independent variables for the modeling process: slope degree, aspect, distance to rivers, stream density, elevation, land use, normalized difference vegetation index (NDVI), plan curvature, profile curvature, topographic wetness index, pH, electrical conductivity, mean annual rainfall, mean weight diameter (MWD), clay, silt, calcium carbonate equivalent (CCE), sodium content, and organic matter. Modeling was conducted using: artificial neural network (ANN), maximum entropy (MaxEnt), and support vector machine (SVM). The performance of algorithms was compared both individually and in combination. Validation results using the receiver operating characteristic (ROC) curve to identify landslide prone areas showed that land subsidence susceptibility maps produced by single MaxEnt model had highest accuracy, with area under the curve (AUC) of 0.92. According to the prioritization of effective factors, elevation and land use were determined to be the most crucial factors for land subsidence. The results of this spatial modeling of land subsidence susceptibility can greatly aid land allocation planning and water resource management in the study area.

Open Access: Yes

DOI: 10.1016/B978-0-443-22262-7.00011-4

Using UTAUT2 modeling to investigate user acceptance of cashless technologies among university students in Hungary

Szabolcs Ramhap Eszter Szabó-Szentgróti Petra Kinga Kézai

Publication Name: Statisztikai Szemle

Publication Date: 2024-01-01

Volume: 102

Issue: 4

Page Range: 344-366

Description:

In recent years, a new retail trend has emerged in the form of cashierless shops. The technology is appearing in more and more countries around the world and we are already seeing this innovative technology in Hungary. This study investigates the user acceptance of this technology among students in Hungarian higher education institutions. It examines the factors that influence attitudes towards cashierless transactions within the adapted framework of the unified theory of acceptance and use of technology (UTAUT2). Seven hypotheses were formulated based on previous literature and the research model. An online questionnaire survey was applied to investigate technology acceptance (n=959). During the questionnaire, respondents rated a total of 29 statements on a Likert scale ranging from 1 to 7. The variance-based structural equations (PLS-SEM) method was used for the research model analysis and hypothesis testing. The results show that the behavioural intention is significantly and positively influenced by performance expectancy, social influence and hedonic motivation. Furthermore, price sensitivity has been shown to have a significant negative effect on behavioural intention. The results of this research can serve as a guide for practitioners and policy makers who are planning to implement this technology. And the diffusion of cashierless technology provides an opportunity to replicate the research by examining the factors that influence actual usage.

Open Access: Yes

DOI: 10.20311/STAT2024.04.HU0344

Example for convex hull tightening increasing the feasible parameter region at Linear Matrix Inequality based control design

Péter Várlaki Alexandra Szollosi Peter Baranyi

Publication Name: Ines 2014 IEEE 18th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2014-09-24

Volume: Unknown

Issue: Unknown

Page Range: 175-180

Description:

The paper shows an example when the tightening of the convex hull determined by the vertexes of the polytopic Tensor Product model representation of a given quasi Linear Parameter Varying state-space model leads to feasible Linear Matrix Inequality based control design. In addition the paper unveils that the relaxation of the Tensor Product model complexity interferes also with the Linear Matrix Inequality feasibility results. The example at hand consists of the complex Nonlinear Aeroelastic Test Apparatus model of the three degree of freedom aeroelastic wing section model including Stribeck friction. The relaxation and convex hull tightening is based on the concept of the Tensor Product model transformation.

Open Access: Yes

DOI: 10.1109/INES.2014.6909364