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Found 6414 publications

Five-day ski camp could enhance postural stability in young adults: A quasi-experimental study

Ferenc Köteles Júlia Patakiné Bősze Áron Horváth Adam Koncz Piroska Béki Attila Szabo

Publication Name: Physiological Reports

Publication Date: 2025-08-01

Volume: 13

Issue: 16

Page Range: Unknown

Description:

This study investigated whether a 5-day ski camp could improve postural stability in young adults. It was hypothesized that skiing would reduce postural sway. In this quasi-experimental design, 43 undergraduate students who participated in a 5-day ski camp (approximately 20 h of skiing) were compared to 35 peers who did not attend. Postural stability was assessed using the modified Clinical Test of Sensory Integration and Balance protocol of the Balance Tracking System, which evaluates sway under four standing conditions: eyes open or closed, and on stable or unstable surfaces. Quade nonparametric ANCOVAs were used to compare percentage change scores between groups, controlling for age. No significant group differences emerged for standard, proprioceptive, or vestibular postural stability (p > 0.05). However, a statistically significant group effect was found for visual postural stability (p = 0.006), with improvement observed only in females (p = 0.003), not in males (p = 0.961). A 5-day ski camp significantly enhanced visual postural stability in females but did not affect males or other postural domains. These findings suggest a potential sex-specific adaptation to skiing and highlight the need for further research into the mechanisms underlying balance improvement.

Open Access: Yes

DOI: 10.14814/phy2.70501

The effects of foreign direct investment on the performance of small-medium enterprises: The case of Vietnam

Laszlo Vasa Norbert Bozsik Duong Minh Ngo

Publication Name: Journal of International Studies

Publication Date: 2023-01-01

Volume: 16

Issue: 1

Page Range: 57-70

Description:

Foreign direct investment (FDI) is one of the most important elements influencing countries' international economic integration. FDI establishes direct, consistent, and long-lasting interconnections between economies as well as encouraging innovative technology and know-how transmission across territories while allowing host economies to offer their goods more extensively on global markets. FDI is also a source of investment financing that creates the climate for appropriate policies. Aside from the obvious advantages for all economic sectors, attracting FDI in small and midsize enterprises (SMEs) has a variety of additional benefits. For example, an opportunity to participate in the global supply chain for parts and components; an opportunity not yet wholly established in most developing nations but is critical for industrialization and improving income distribution through job creation for low-skilled employees. This study compared the impact of FDI on the performance of SMEs in Vietnam to that of a group of ASEAN nations with comparable economic structures including Indonesia, Malaysia, and Thailand. The empirical evidence indicates that FDI has a negative effect on the performance of SMEs in the group of four ASEAN member countries while having a positive influence on Vietnamese SMEs.

Open Access: Yes

DOI: 10.14254/2071-8330.2023/16-1/4

Investigation of swings caused by sudden wind loads during operation of an aerial ladder

Péter Horváth F. Hajdu Rajmund Kuti

Publication Name: Fme Transactions

Publication Date: 2020-01-01

Volume: 48

Issue: 2

Page Range: 351-356

Description:

In Hungary, as in other countries around the world, intervention firefighting units often use a mechanically operated aerial ladder for highaltitude rescue tasks. The safe operation of the equipment is only possible under strict safety regulations and requires a high level of expertise from the operating staff. During each intervention, extraordinary events such as sudden wind gusts can occur, which can cause extreme overload of the structural members of aerial ladders and have adverse effects on the equipment that can lead to malfunctions and-even worse-to accidents. Therefore it is important to study the consequences of external influences on aerial ladders during operation. The examination was performed on a widely used Magirus M32-L aerial ladder. The reason for choosing this type of aerial ladder is because it has a wide operating range, therefore test results can be a good starting point for other similar equipment as well. In this paper the development of our beam model and the performed finite element simulations are presented. The aim of the research is to develop a model based on geometrical measurement data that is suitable for studying the effects of wind gusts on the ladder structure. With our research, we aim to contribute to the safe operation of aerial ladders and to prevent possible accidents.

Open Access: Yes

DOI: 10.5937/FME2002351H

Reconstruction decision model for trasportation infrastructure systems

István Pályi Ildikó Gombaszögi Lajos Tóth Peter Varlaki

Publication Name: Isciii 07 3rd International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 163-166

Description:

Improving transportation infrastructure raises several questions requiring complex analysis. Creating the mathematic model for transportation reconstruction needed developing a quick, dynamic programming process which considers the costs of single reconstruction phases and the direct or indirect profit emerging after completing reconstruction works. In the study we examined the application possibilities of the highly prestigious Bellman-theorem. We found that the combinatorial method for optimal distribution of investments is not very efficient in the current issue, although it applies the sequential method and the Bellman-theorem in a remarkable way. The method proposed in the study applies exponential partial profit-functions. The primary advantage is that it solves the problem of the complicated nonlinear dynamic programming on the basis of direct relations, without numeric analysis. Consequently, results are supplied quickly and the method allows solving enormous problems without any constraints. © 2007 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2007.367382

Development of High-Speed Railway Network in Europe: A Case Study of Ukraine

Szabolcs Fischer Mykola Kurhan Dmytro Kurhan Oleksii Tiutkin Nelya Hmelevska

Publication Name: Periodica Polytechnica Transportation Engineering

Publication Date: 2024-01-01

Volume: 52

Issue: 2

Page Range: 151-158

Description:

The current task today is the development of theoretical and methodological approaches, as well as practical recommendations for determining the technical feasibility of creating high-speed railway (HSR) lines in the European context. The development of railways in individual countries, followed by the creation of a pan-European high-speed railway network, has raised questions about the compatibility of the technical systems of individual national HSRs. This paper addresses these issues using the example of Ukraine. The research is based on an analysis of scientific developments related to the design of HSR lines and the synthesis of European experience in identifying priority route directions in Ukraine. For comparing various scenarios for the development of railway connections, the authors have developed a forecasting and efficiency assessment model based on the Net Present Value (NPV) indicator. It has been demonstrated that considering the population attracted to HSR and the volume of transit passenger transportation alone is insufficient to achieve the normative investment payback. This situation can only be rectified by implementing mixed traffic involving high-speed passenger trains and accelerated freight trains. However, mixed traffic of passenger and freight trains on high-speed rail lines may face numerous issues and constraints that require careful planning and coordination.

Open Access: Yes

DOI: 10.3311/PPtr.23464

Modeling of soil-stucture interaction in bridge design

János Szép Róbert Szepesházi

Publication Name: Icsmge 2017 19th International Conference on Soil Mechanics and Geotechnical Engineering

Publication Date: 2017-01-01

Volume: 2017-September

Issue: Unknown

Page Range: 859-862

Description:

In bridge design use of integrated models for analysing of substructure (including foundation) and subsoil together with superstructure is quite rare, a separated approach using two interconnected models is more often. In this paper we present methods to use in structural modeling for modeling substructure, foundation and soil with emphasis on piles. In the simplest method prescribed displacements are applied on rigid supports to represent all the effects of pile foundation and surrounding soil. An advanced approach is the use of springs for modelling their complex response. Some designers include the piles in the superstructure model too, and require spring parameters for modeling the soil beside each pile element. We present how to determine spring characteristics for these approaches based on traditional analytical geotechnical consideration or force-displament curves measured or simulated. Another probably a better way could be to represent the entire support response in the superstructure modeling, especially in the case of abutments. The complex interactions can be analysed only by advanced geotechnical FEM modeling and the results can be used for deriving of simplified spring parameters as shown in this paper.

Open Access: Yes

DOI: DOI not available

Theoretical models of cross-border integration

Tamás Hardi Andrea Uszkai

Publication Name: Socialni Studia Social Studies

Publication Date: 2017-01-01

Volume: 14

Issue: 1

Page Range: 9-30

Description:

This article attempts to summarize the most important definitions and theoretical models related to cross-border spatial integration based on scientific literature. It would not be possible without defining several border phenomena, because different types of borders have distinct features and form space differently. The role of borders has constantly changed over time, depending on the historical, political, geographical and other characteristics of the given region. There were times when a given border was easily permeable and at other times it was difficult to cross. Therefore, the depth of integration is also changeable. This article tries to collect the most important theoretical models which explain these cross-border spatial processes and emphasizes the importance of the characteristics of urban networks in cross-border integration. We think there are many conceptual models in international border studies which explain several border processes from different points of view, but they are not properly collected in order to explain the cross-border integration process. In addition, some theoretical models are inadequately positioned in the research of cross-border integration that is why we intend to analyze their relevance to this topic as well. Hopefully, our work will help to understand the main factors and elements influencing crossborder integration through the explanatory theoretical models collected here.

Open Access: Yes

DOI: 10.5817/soc2017-1-9

Machine Learning for Multi-Fault Classification in Park's Vector Trajectories of PMSMs

Adrienn Dineva Adam Zsuga

Publication Name: 2024 IEEE 22nd Mediterranean Electrotechnical Conference MELECON 2024

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 133-137

Description:

Space Vector Theory, also known as Park's Vector Method, is a frequently utilized technique for analyzing, modeling, and controlling electrical machines and drives. In motor diagnostics applications based on Park's Vector trajectory patterns, the assistance of domain experts is indispensable for Fault Detection and Diagnosis (FDD). Yet, simultaneously occurring faults may lead to feature overlap or accumulation, posing additional challenges for identification. In this paper a comparative analysis of automating Park's Vector Approach is presented, with combining the method with advanced ML techniques. Utilizing a magnetics-based Permanent Magnet Synchronous Motor (PMSM) model, a custom simulated fault dataset is created for training purposes. The dataset is used to train three distinct models: a Siamese Network, EfficientNet and the Vision Transformer model. Throughout the evaluation, key classification metrics including the F1-score, precision, and recall are analyzed, alongside an examination of the training curves. The results indicate that the Park's Vector Approach combined with State-of-the-Art ML models efficiently detects anomalies and multiple faults. It highlights the models' ability to identify local features, accurately classify, and detect simultaneous faults, which is often challenging for domain experts due to the difficulty in distinguishing fault features of multiple faults even through visual inspection.

Open Access: Yes

DOI: 10.1109/MELECON56669.2024.10608573

The effect of initial pattern on competitive exclusion

Éva Veronika Pestiné Rácz János Karsai

Publication Name: Community Ecology

Publication Date: 2006-08-01

Volume: 7

Issue: 1

Page Range: 23-33

Description:

We used cellular automata models to investigate the effect of initial pattern geometry on competition. We measured the average proportion of sites with foreign neighbours to track interspecific segregation during pattern development. Our simulation results show that intraspecific aggregation can considerably slow down the extinction of the weaker competitor. A series of experiments was performed to estimate the expected time to extinction for the weaker species. The perimeter-to-area ratio of the initial configuration proved to be an adequate determinant of expected time to-extinction. Furthermore, we demonstrated that the degree of aggregation is closely related to the local density dependence of the colonization functions.

Open Access: Yes

DOI: 10.1556/ComEc.7.2006.1.3