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Found 6374 publications

Comparison of performance calculation methods for solar PV systems

T. Horváth David Bozsaky Kitti Karolyfi Olivér Tóth Dániel László Hegedűs Árpád Hajdu Dóra Szalai

Publication Name: Pollack Periodica

Publication Date: 2026-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

AbstractPhotovoltaic systems are increasingly applied in buildings to reduce energy costs and support sustainability. Their performance depends on factors such as panel angle, orientation, and temperature, which significantly affect energy yield. This study compares the actual output of an operating photovoltaic system with results from three calculation methods: manual estimation, 3D modeling, and artificial intelligence-based evaluation. The photovoltaic geographical information system and Rhino-Grasshopper methods proved most accurate, deviating by less than 10% from measured data due to their use of extensive, long-term meteorological datasets that ensure reliable performance prediction.

Open Access: Yes

DOI: 10.1556/606.2026.01532

Rényi 100, Quantitative and qualitative (in)dependence

J. Pintz Miklós Arató Gy Michaletzky T. Rudas T. F. Móri G. Tusnády G. J. Székely Gy O.H. Katona

Publication Name: Acta Mathematica Hungarica

Publication Date: 2021-10-01

Volume: 165

Issue: 1

Page Range: 218-273

Description:

We discuss recent developments in the following important areas of Alfréd Rényi’s research interest: axiomatization of quantitative dependence measures, qualitative independence in combinatorics, conditional qualitative independence in statistics/data science and in measure theory/probability theory, and finally, prime gaps that are responsible for Rényi’s early career reputation. Most authors of this paper are main contributors to the new developments.

Open Access: Yes

DOI: 10.1007/s10474-021-01164-4

Invariance Preserving Discretization Methods of Dynamical Systems

Yunfei Song Tamás Terlaky Zoltán Horváth

Publication Name: Vietnam Journal of Mathematics

Publication Date: 2018-12-01

Volume: 46

Issue: 4

Page Range: 803-823

Description:

In this paper, we consider local and uniform invariance preserving steplength thresholds on a set when a discretization method is applied to a linear or nonlinear dynamical system. For the forward or backward Euler method, the existence of local and uniform invariance preserving steplength thresholds is proven when the invariant sets are polyhedra, ellipsoids, or Lorenz cones. Further, we also quantify the steplength thresholds of the backward Euler methods on these sets for linear dynamical systems. Finally, we present our main results on the existence of uniform invariance preserving steplength threshold of general discretization methods on general convex sets, compact sets, and proper cones both for linear and nonlinear dynamical systems.

Open Access: Yes

DOI: 10.1007/s10013-018-0305-z

Municipal Household Waste Management Methodologies in the EU Countries: A Reverse Logistics Benchmarking Approach

Edit Süle László Buics Marah Almelhem

Publication Name: Lecture Notes on Multidisciplinary Industrial Engineering

Publication Date: 2025-01-01

Volume: Part F4026

Issue: Unknown

Page Range: 100-109

Description:

Through the application of a reverse logistics benchmark approach, this paper aims to investigate prevailing waste management practices in the European Union (EU) countries. In detail, it will analyze existing waste management practices, identify successful efforts, and identify areas for improvement within the EU region, in order to answer how can different collection waste management practices promote sustainability and integrate with reverse supply network? In this article, a structured literature review is carried out to examine the existing literature background, and public reports are collected and analyzed published by EU nations on waste management. The aim of the article is to understand their current state and evaluate the applicability of reverse logistics techniques in enhancing waste collection, recycling, and disposal. By answering the research question, the examination can provide valuable insights and recommendations for policymakers, as well as those involved in managing waste or stakeholders with an interest in enhancing the sustainability and efficiency of waste management practices in EU countries.

Open Access: Yes

DOI: 10.1007/978-3-031-80330-7_11

Age-dependent aerobic capacity among young and middle-aged males

Ferenc Ihász József Bognár Balázs Fügedi Piroska Boros Peter Szabó Andras Oláh

Publication Name: Gazzetta Medica Italiana Archivio Per Le Scienze Mediche

Publication Date: 2016-03-01

Volume: 175

Issue: 3

Page Range: 68-75

Description:

BACKGROUND: Good aerobic capacity is one of the attributes of good cardiovascular function. Physical activity that is performed in steady state and the lower third zone of submaximal intensity seems appropriate for physiological adaptation in advancing age. There is a need to evaluate the effect of age on physiological variables contributing to aerobic capacity using submaximal intensities. The purpose of this study is to analyze the differences m oxygen uptake, oxygen pulse, and minute ventilation during exercise at steady state, ventilatory threshold, and maximal intensity zones among men of different ages. METHODS: Three hundred and twelve senior managers m three age groups (20-30, 30-40, and 40-50) completed an exercise protocol in six stages. RESULTS: Hie result demonstrated a series of differences among the age groups: height, weight, oxygen uptake, oxygen pulse and relative minute ventilation. Accordmg to these results the morphological physiological variables decline with age. CONCLUSIONS: These findings demonstrate the specificities of the morphological, ventilatory, metabolic, and cardiovascular changes throughout aging. When designing a physical activity program, it seems that similar principles can be followed in different age groups; however, maximal intensity maintenance is limited by physiological barriers m older adults. (Cite this article as: Ihasz F, Boros P, Szabo P. Olah A, Fueedi B. Bognar J. Age-dependent aerobic capacity among young and middle-aged males. Gazz Med Ital - Arch Sci Med 2016;175:68-75).

Open Access: Yes

DOI: DOI not available

Special coginfo application by non-business organizations: Case study on marketing communication of a higher education institution

Márta Konczos Szombathelyi Eszter Petra Majer Szabolcs Ramhap

Publication Name: 6th IEEE Conference on Cognitive Infocommunications Coginfocom 2015 Proceedings

Publication Date: 2016-01-25

Volume: Unknown

Issue: Unknown

Page Range: 483-488

Description:

The aim of this study is to prove that non-business organizations (among them the universities) - increasingly often facing the effects of lack of sources and operating in fierce competition - need to use such marketing systems and IT telecommunication technologies which are applied by profit-oriented sectors. Changes and processes in the field of information technology and telecommunications are fast, wide spread and revolutionary, even aggressive. This analysis is based upon the experiments and data of Service Centre of Széchenyi University. The key findings of this paper is the conclusion that for the higher education institution is vital for applying infocommunication tools for reaching the cognitive entities, the young generations. The paper focuses on the development of communication channels, online communication and social media, furthermore tends to give an overall picture of the rapidly growing role of social media as a tool among Hungarian higher institutions. The financial position of institutions depends more and more on customer behaviour. Customer behaviour has an influence on the higher education market; it has an effect on the choice of institution and also on future target groups. So it is significant for these institutions to pay attention to consumer expectations and communicate effectively with their consumers, using the latest and the most advanced information communication technologies. It is particularly important because the universities' target groups are mostly the Y and Z generations into whose everyday activities modern info communication technologies are embedded. In the frame of our paper we give an overview of the trends and long term features - such as digitalization, info-communication, and social media - on marketing communication tools at Széchenyi University. The case study shows the multifaceted nature of the problem, the range of possible tools and their application. Due to the labour market needs Széchenyi István University strengthens relations with the business sector and broadens the range of teaching and research services provided by them. In the case study we can follow the development of communication channels/instruments; the digital evolution and the phenomenon that the social web has become the most important (strategic) platform for communicating with the young generations; overall trends in interactive communication and online communities, and the emergence of interactive channels; social media, networks and online videos. The universities have to employ professionals with social media skills and they have to create communicating strategies for different generations. We have a real case about how younger "always online" communication professionals formulate the core requirements; and how we can integrate the communication centre with the newest info communication tools, such as mobile communication: applications. We can conclude that as the World Wide Web becomes more and more influential, social media has become the most important tool of marketing communication for universities to reach the public.

Open Access: Yes

DOI: 10.1109/CogInfoCom.2015.7390641

Computational Procedure for Determining the Shear Yield Stress-Shear Deformation Relationship in Magnetorheological Fluids from Anton-Paar Measurement Data

Dávid Törocsik Péter Horváth

Publication Name: Strojnicky Casopis Journal of Mechanical Engineering

Publication Date: 2024-11-01

Volume: 74

Issue: 2

Page Range: 25-34

Description:

In the past decade, magnetorheological fluids have been applied in various devices. This article focuses on developing a new computational procedure to determine the shear strength-shear strain relationship of magnetorheological fluids from the measurement data obtained by using an Anton-Paar rotational viscometer.

Open Access: Yes

DOI: 10.2478/scjme-2024-0022

Control of underactuated systems based on machine learning model: case studies

Ambrus Zelei

Publication Name: Multibody System Dynamics

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Besides traditional modelling approaches, machine learning surrogate models have become widespread. In addition to existing concepts, this work investigates the use of neural networks (NNs) to replace dynamic equations in multibody systems. While physics-informed neural networks (PINNs) dominate recent literature, their constraint enforcement via cost-function penalties poses tuning challenges. This paper proposes an alternative: training NNs on data with intentional constraint violations to implicitly learn stabilisation, avoiding PINN limitations. The proposed concept is applied to the inverse dynamics control of underactuated systems, where the task is defined by servo-constraints. Using Scikit-learn’s MLP Regressor, we demonstrate NN-based surrogate modeling in three levels: 1) forward dynamics of minimum-coordinate models, 2) constrained models, and 3) the inverse dynamics control of underactuated multibody systems via servo-constraints, which is a classical approach not yet combined with NNs. The neural network model is used to represent the inverse dynamics model, for which training data are generated through forward dynamic simulations. The study demonstrates that low-degree-of-freedom planar systems can be approximated by middle-scale neural network models of a few hundred perceptrons, requiring training times of minutes on a personal computer. The proposed control architecture can stabilise the servo-constraints and track trajectories, even for non-collocated underactuated systems where traditional methods might fail. The results highlight a simple, industry-friendly path for NN-based MBD control.

Open Access: Yes

DOI: 10.1007/s11044-025-10116-7

Observability Conditions for Speed Sensorless Induction Motor Models with Neglected or Included Iron Loss Representation

Krisztian Horvath

Publication Name: International Conference on Electical Drives and Power Electronics

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: 97-101

Description:

Iron loss is usually neglected in induction motor models used for speed sensorless control and observer design. Thus, the complexity of control and estimator algorithms are reduced. However, the application of a more accurate model can improve the performance, hence the inclusion of iron loss in the machine model is becoming more widespread. But the effect of iron loss modeling on observability has not been analyzed yet. In this paper, observability conditions are presented for nonlinear state-space models with included iron loss. Furthermore, the results are compared with the observability properties of the traditional models where iron loss is ignored.

Open Access: Yes

DOI: 10.1109/EDPE53134.2021.9604110