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Found 6414 publications

The most important city development initiatives of Hungary

János Rechnitzer Bálint Filep Judit Berkes

Publication Name: Regional Statistics

Publication Date: 2019-01-01

Volume: 9

Issue: 2

Page Range: 20-44

Description:

Recently, Hungary's urban development issues have been gaining increasing attention, while directions and institutional frameworks of regional politics are in a constant change. In this context, the study discusses the contents and connotations that can be linked to the territorial concept of major Hungarian cities; it also examines the changes in the position of these cities in the urban system. Major cities have a key role in territorial development as they facilitate spatial processes, and hence it is crucial to identify the weight and directions these centres with complex functions represent in development concepts. The formation or even restructuring of spatial processes require time. Since the democratic transition in 1989-1990, different development directions were assigned to major cities in short cycles. Cities have failed to adapt to these ever-changing objectives. The first part of this study presents the layers of the concept of major cities and characterize such categories as regional centre, city, county seat, and city with county rights. The second part tries to locate these centres, exploring changes in their developmental emphases, and also identifies pathways in the frequently changing territorial politics of the posttransition period.

Open Access: Yes

DOI: 10.15196/RS090204

Estimation of Milk Casein Content Using Machine Learning Models and Feeding Simulations

István Szabó Bence Tarr András Revoly János Tőzsér

Publication Name: Dairy

Publication Date: 2025-08-01

Volume: 6

Issue: 4

Page Range: Unknown

Description:

Milk quality has a growing importance for farmers as component-based pricing becomes more widespread. Food quality and precision manufacturing techniques demand consistent milk composition. Udder health, general cow condition, environmental factors, and especially feed composition all influence milk quality. The large volume of routinely collected milk data can be used to build prediction models that estimate valuable constituents from other measured parameters. In this study, casein was chosen as the target variable because of its high economic value. We developed a multiple linear-regression model and a feed-forward neural network model to estimate casein content from twelve commonly recorded milk traits. Evaluated on an independent test set, the regression model achieved R2 = 0.86 and RMSE = 0.018%, with mean bias = +0.003% and slope bias = −0.10, whereas the neural network improved performance to R2 = 0.924 and RMSE = 0.084%. In silico microgreen inclusion from 0% to 100% of dietary dry matter raised the predicted casein concentration from 2.662% to 3.398%, a relative increase of 27.6%. To extend practical applicability, a simulation module was created to explore how microgreen supplementation might modify milk casein levels, enabling virtual testing of dietary strategies before in vivo trials. Together, the predictive models and the microgreen simulation form a cost-effective, non-invasive decision-support tool that can accelerate diet optimization and improve casein management in precision dairy production.

Open Access: Yes

DOI: 10.3390/dairy6040035

Semi-empirical model for predicting the swelling stress of compacted, unsaturated expansive soils

Elizabeth Theron Armand Augustin Fondjo Richard P. Ray

Publication Name: Civil Engineering and Architecture

Publication Date: 2021-01-01

Volume: 9

Issue: 1

Page Range: 225-239

Description:

Heaving soils are the most problematic worldwide. These soils develop swelling stress that produces uplift forces detrimental to the foundations. In engineering practice, swelling stress is not considered in general. Considering the swelling stress in foundation design enhances the service life of construction. The oedometer swelling test is the technique ordinarily used to assess the swelling stress. Nonetheless, the oedometer swelling test is cumbersome, time-consuming, making the test unattractive, and not cost-effective for the low-cost housing project. The objective of this research work is to propose a model to predict swelling stress as an alternative to oedometer testing. Geotechnical studies such as Atterberg limits, particle size distribution, free swell ratio, specific gravity, linear shrinkage, suction measurement, Proctor compaction test, and zero-swell test are performed to estimate the soil properties. Multivariate regression analysis is performed using NCSS.11 Program to develop the predictive model. The model is assessed base on the following: determining coefficient value, comparing predicted values with experimental values, comparing the proposed model with other existing models found in the literature. Besides, the Box-cox transformation function is used to improve the accuracy of the model. The developed model can be utilized to assess the swelling stress of compacted heaving soils, and it is much more accurate than other existing models.

Open Access: Yes

DOI: 10.13189/cea.2021.090119

On the lower limit for possibilistic correlation coefficient with identical marginal possibility distributions

Istvan A. Harmati Robert Fuller

Publication Name: Studies in Computational Intelligence

Publication Date: 2019-01-01

Volume: 794

Issue: Unknown

Page Range: 99-113

Description:

In 2011 Fullér et al. [An improved index of interactivity for fuzzy numbers, Fuzzy Sets and Systems, 165 (2011), pp. 50–60] introduced a new measure of interactivity between fuzzy numbers (interpreted as possibility distributions), called the weighted possibilistic correlation coefficient, which can be determined from their joint possibility distribution. They also left two questions open regarding the lower limit of the weighted possibilistic correlation coefficient of marginal possibility distribution with the same membership function. In this paper we will answer these questions not only in the case of fuzzy numbers, but also for quasi fuzzy numbers.

Open Access: Yes

DOI: 10.1007/978-3-030-01632-6_7

Development of Magnetic Hysteresis Loop Measurement System for Characterization of 3D-Printed Magnetic Cores

Tamas Orosz Miklos CSIZMADIA Tamás Horváth

Publication Name: Electronics Switzerland

Publication Date: 2025-06-01

Volume: 14

Issue: 11

Page Range: Unknown

Description:

Today, numerous advanced options exist for analyzing and measuring magnetic hysteresis loops and core loss across a broad spectrum of applications. Most of these systems are compact and ready to use, fulfilling the measurement and data processing requirements for laminated iron cores according to the standards. However, modeling newly developed materials with complex structures or the high-frequency behavior of iron cores, and the computation of dynamic hysteresis properties’ temperature dependence, are still challenging problems in the field. Moreover, these standardized measurement tools are relatively expensive, and most of them represent a black box that impedes research and further development. This paper presents the development of a cheap and accessible measurement system that is explicitly designed for recording the hysteresis properties of 3D-printed iron cores. The paper presents a comprehensive overview of the design process, components, circuitry, and simulations integral to this project. The paper presents a completed circuit simulation conducted using LTspice and validation of the prototype’s measurement performance. The measurements obtained with the proposed system show good agreement with those of the reference setup, demonstrating its accuracy and practical applicability.

Open Access: Yes

DOI: 10.3390/electronics14112235

Optimization and finite element analysis of 3-pole magnetic bearing with nonlinear material

Miklós Kuczmann Dániel Marcsa

Publication Name: Przeglad Elektrotechniczny

Publication Date: 2010-12-20

Volume: 86

Issue: 12

Page Range: 91-94

Description:

This paper deals with the design and numerical simulation of a radial active magnetic bearing. This bearing is a Y-shaped three-pole magnetic bearing fed by two amplifiers. The geometry design is based on the analytical computation and numerical optimization based on nonlinear finite element analysis. The nonlinearity has been handled by the Newton-Raphson method.

Open Access: Yes

DOI: DOI not available

An Approach for Hierarchical Clustering of Road Vehicle Vibration Spectrums

Péter Földesi László Róbert Hári

Publication Name: Lecture Notes in Mechanical Engineering

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: 799-811

Description:

Research on the non-stationary nature of road vehicle vibrations (RVV) led to advances in simulating such processes. Contemporary methods introduced for the analysis of RVV primarily aimed at partitioning the signal in the time- or time − frequency domain, providing differing segments of a signal. However, a degree of dissimilarity, or conversely similarity, is still challenging to find. Hereunder we argue that in some cases, merely a statement of dissimilarity between neighbouring segments within a signal might be well-enough, though from a broader perspective, the assessment of the similarity of discrete Fourier transforms (DFT) may be the next practical step forward. For this reason, the current paper presents the hierarchical clustering of elements of the short-time Fourier transform (STFT) plane from an RVV measurement; secondly, it introduces a clustering validation metric to arrive at an optimum distance metric and a threshold to use in binary hierarchical clusters.

Open Access: Yes

DOI: 10.1007/978-3-031-15211-5_66

Combustion and Emission Analyses of a Diesel Engine Running on Blends with Methanol

Justas Žaglinskis Kristóf Lukács György Szabados Ákos Bereczky

Publication Name: Energy Environment and Sustainability

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: 141-172

Description:

The ambient air around us is continuously and increasingly loaded and polluted through emission that comes from different sectors, especially from the transportation sector. This fact is due to the growing energy consumption in the transport sector which is forecasted worldwide in the nearer and far future. Bio-based energy may be consumed in an increasing way in the sector until 2050. Methanol, and if it is produced on bio-basis, called bio-methanol, is the simplest alcohol. Methanol costs less than other automotive alternative alcohols, for example, ethanol or butanol, so it may be among the cheapest technical alcohols. As for methanol’s structure, it contains 30% more inherent oxygen on a molecular base than fossil diesel. The aim of this research is to give comprehensive overview about the methanol’s effect on the combustion and emission properties of a diesel engine. During the analyses of combustion and emission characteristics the most relevant parameters have been included. The study also contains calculations regarding theoretical combustion (oxidation process) of the different hydrogen-carbons. A rarely investigated parameter, O2 consumption or demand is also in focus, besides CO2 emission and intensity throughout the calculations. For our experimental test series, diesel fuel was the base fuel and it has been mixed with biodiesel first, and this mixture has been further blended with methanol. Methanol’s theoretical contribution to the diesel–biodiesel blend’s O2 consumption and CO2 emission is a small amount. Engine’s external parameters have not changed significantly if it is running on blend with methanol. Methanol has rather affected the combustion and emission properties of the engine more significantly.

Open Access: Yes

DOI: 10.1007/978-981-16-1280-0_6

Residual Stresses in Carburised, Carbonitrided and Case-hardened Components (Part 1)

Tamás Réti

Publication Name: Heat Treatment of Metals

Publication Date: 2003-12-08

Volume: 30

Issue: 4

Page Range: 83-96

Description:

The assesment of residual stress effects in carburised, carbonitride and case-hardened components was discussed. The development of computational models and procedures, which were applied to the simulation of the stress-evolution processes during heat treatment was also discussed. Shot peening, the most versatile method of producing residual stresses was studied. The influence of microstructure and residual stresses on crack initiation and propagation was discussed.

Open Access: Yes

DOI: DOI not available