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Found 6515 publications

Potential formulations for solving TEAM problem 27

Miklós Kuczmann Zoltán Pólik

Publication Name: Przeglad Elektrotechniczny

Publication Date: 2009-12-01

Volume: 85

Issue: 12

Page Range: 137-140

Description:

This paper presents a study of using two potential formulations-the A z.ast;-A formulation, and the T, Φ - Φ formulation-to solve the TEAM problem No. 27 (Eddy Current NDT and Deep Flaws). A procedure to determine arbitrary periodic excitation signal by using Fourier series will also be shown. The numerical results are compared with the experimental waveforms. The goal of this work is to find the more precise and the faster formulation and to approximate the response of a linear electromagnetic system, when the excitation is a periodic signal.

Open Access: Yes

DOI: DOI not available

Psychometric Properties of the Hungarian UCLA Loneliness Scale Among Adolescents: A Search for the Meaning of Loneliness in the Young Population

Ferenc Ihász Johanna Takács Zsolt Bálint Katona

Publication Name: European Journal of Mental Health

Publication Date: 2024-01-01

Volume: 19

Issue: Unknown

Page Range: Unknown

Description:

Introduction: Loneliness has been considered a major public health and policy concern, with substantial physical and mental health impacts.The University of California and Los Angeles Loneliness Scale (UCLA-LS) is one of the most widely used scales for measuring loneliness but it does not have robust psychometric properties among adolescents.Aims: To evaluate the psychometric properties of the Hungarian UCLA-LS among adolescents.Methods: The sample includes a total of 2508 students, 57.3% females, aged between 14 and 21 years.Studying psychometric properties, internal reliability and criterion-related validity were measured.The sample was randomly divided into two parts to examine the factorial structure: one part was used for exploratory factor analysis (EFA) and the other was used for confirmatory factor analysis (CFA).Results: The UCLA-LS showed good internal consistency.Its total score and the single-item measure showed a small correlation, and also indicated a significant moderate association with hopelessness and self-reported well-being.Based on the EFA, we identified two factors with 51.7% of the total variance explained.In the CFA, the two-factor model demonstrated a good fit.Conclusions: The findings suggested that the Hungarian UCLA-LS can be a reliable and valid tool for adolescents to measure some dimensions of loneliness.We confirmed the non-normal, relatively skewed distribution of the scale.We can conclude that the UCLA-LS measures a trait characteristic of loneliness.In the adolescent population, it is recommended to use further measures of loneliness to gain more information about the frequency and nature of the multi-faceted mental representation of loneliness.

Open Access: Yes

DOI: 10.5708/EJMH.19.2024.0034

Hammerstein Model Identification for Autonomous Vehicle Dynamics by Two-Stage Algorithm †

György Terdik Dániel Pup György Istenes József Bokor

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

In this paper, the nonlinear identification (ID) of the lateral dynamics of a road vehicle is presented. The mathematical description of lateral dynamics is crucial for developing various self-driving functions. One method of describing dynamics is system identification from measured data. During the measurements, the steering servo of a test vehicle kept in straight-line motion by a self-driving function was artificially excited. A Hammerstein–Wiener model was successfully applied for the identification of these measurements. A nonlinear estimator was used during the fitting, which needed high computing power. For the Hammerstein–Wiener model, we used the two-stage algorithm (TSA) with a bilinear estimation method, which makes it possible to apply linear regression. We compared these methods during simulations and real data.

Open Access: Yes

DOI: 10.3390/engproc2024079054

System identification with generalized Prony schemes

Ferenc Schipp Tamás Dózsa Bokor Jozsef Gergo Ungvari Alexandros Soumelidis

Publication Name: Proceedings of the American Control Conference

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: 5086-5092

Description:

We propose a novel method to identify the transfer functions of single-input-single-output linear time invariant (SISO-LTI) dynamic systems. Our approach makes use of the operator based generalization of Prony's method. In particular, the operator based Prony algorithm is used to reconstruct the transfer function of the system as a linear combination of rational basis functions. A considerable benefit of the proposed method is its robustness against the estimated system order. That is, if system order is over estimated, the correct system order can be found naturally. Another important benefit is that the proposed method is shown to be asymptotically robust towards zero expectation noise with the correct choice of certain evaluation functionals. The effectiveness of the proposed method is demonstrated through numerical experiments.

Open Access: Yes

DOI: 10.23919/ACC63710.2025.11107575

Analysis of stress-strain state changes in railway tracks during transition to European gauge

Szabolcs Fischer Mykola Kurhan Dmytro Kurhan Nelya Hmelevska

Publication Name: Iop Conference Series Earth and Environmental Science

Publication Date: 2024-01-01

Volume: 1348

Issue: 1

Page Range: Unknown

Description:

The geographical location of Ukraine facilitates its integration into the transportation network connecting European countries. Various options exist for transitioning from the gauge of 1 520 mm to the European standard gauge of 1 435 mm. This paper aims to analyze the changes in the stress-strain state of railway track elements during the reconstruction of existing sections from the 1 520 mm gauge to the 1 435 mm European gauge or to a dual gauge of 1 435/1 520 mm. To perform these calculations, a spatial model of dynamic deformations in the railway track is employed, based on the principles of elasticity theory. The implementation of a combined railway track complicates the stress state of the ballast layer, leading to asymmetric stresses along the length of the sleepers, which vary depending on the track on which trains operate. There is also a redistribution of stresses acting on the ground structure, which has been in operation for many years. The research results identify changes in the stress-strain state of the railway track and can be used to justify measures for the appropriate reinforcement of the ballast layer and the ground structure.

Open Access: Yes

DOI: 10.1088/1755-1315/1348/1/012029

Linear-Matrix-Inequality-Based Controller and Observer Design for Induction Machine

Miklós Kuczmann Zoltan Nemeth

Publication Name: Electronics Switzerland

Publication Date: 2022-12-01

Volume: 11

Issue: 23

Page Range: Unknown

Description:

The modeling and drive control of electric machines are still actively researched scientific topics. Most of the existing models contain parameters that have no physical content or cannot be measured at all. For this reason, the use of observers in modern drive control algorithms is necessary. The main goal of this paper is to present the mathematical formalism of a linear matrix inequality (LMI)-based controller-observer design for a tensor product (TP) transformation-based model, including its implementation in a simulation environment. Based solely upon simulation results, the designed observer can provide a stable and accurate state space variable, regardless of the highly nonlinear induction machine model.

Open Access: Yes

DOI: 10.3390/electronics11233894

Computational intelligence for gestural communication using emotional model

János Botzheim Bakhtiar Yusuf Toru Yamaguchi Naoyuki Kubota

Publication Name: Iwaciii 2013 3rd International Workshop on Advanced Computational Intelligence and Intelligent Informatics

Publication Date: 2014-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

When conducting natural communication in addition to perform verbal communication, non-verbal communication such as gestural information should also be understood. By the word "understand" we mean not only the recognition of one action, but also grasp the meaning of the gesture itself. Therefore, in order to understand the meaning of an action, in this paper we propose emotional model along with the gesture recognition technique. First we discuss the gesture recognition method using iPhone camera by applying steady state genetic algorithm, spiking neural network and self organizing map. After that we use the gesture recognition result as an input data for the emotional model.

Open Access: Yes

DOI: DOI not available

Observation of zonal flow-like structures using the autocorrelation-width technique

M. Berta J. Adamek M. Hron S. Zoletnik A. Bencze J. Stockel

Publication Name: Plasma Physics and Controlled Fusion

Publication Date: 2006-04-01

Volume: 48

Issue: 4

Page Range: S137-S153

Description:

This paper presents the first application of the autocorrelation-width technique (Bencze A and Zoletnik S 2005 Phys. Plasmas 12 052323) to detect and characterize the microturbulence-zonal flow system using fluctuating signals ( , ) measured by arrays of single-tip Langmuir probes in the CASTOR tokamak. Radially localized (≈1 cm) random flow structures have been clearly observed with a lifetime of ≈1 ms and a long-range poloidal correlation, extending over at least one-fourth of the poloidal circumference. © 2006 IOP Publishing Ltd.

Open Access: Yes

DOI: 10.1088/0741-3335/48/4/S10

Psychological foundations of solo dining experience in tourism and hospitality industry. A mixed methods study

Priyanka Malik Lata Bajpai Singh Ebtesam Abdullah Alzeiby Attila Kurucz Nidhi Sahore

Publication Name: Acta Psychologica

Publication Date: 2026-06-01

Volume: 266

Issue: Unknown

Page Range: Unknown

Description:

Solo dining has gained substantial recognition in the restaurant business worldwide. Considering the growing trend of solo dining, it has attracted increasing interest from academia and industry. Since the current stage of knowledge on solo dining practices and their management is limited and scattered, it requires integration to provide scholars with an outline of the current state of knowledge in this field, as well as the industry expert insights. To address this issue, the current study applies a mixed-method approach to first gather insights from the existing literature by conducting a systematic literature review (SLR). Subsequently, in order to substantiate SLR findings, a qualitative study is designed to garner industry expert views on solo dining experience, enhancing restaurant practices and strategies. The SLR has revealed three distinct thematic areas, such as solo dining antecedents, solo diner's experience while dining, and the solo diner's outcome behaviour. Based on these insights, it was necessary to identify the practical takeaways for the restaurants in the hospitality industry; therefore, a qualitative study was designed following the mixed-method approach of research design. The empirical results present solo dining strategies implemented by restaurant owners and staff. The Gioia technique of qualitative analysis of data brought forward four solo dining aggregate dimensions presenting the solo diner's profile, adaptive comfort, human touch, and restaurant strategies. This study makes a novel contribution to the solo dining literature by identifying psychophysiological aspects of solo dining and offering managerial insights for restaurant industry professionals.

Open Access: Yes

DOI: 10.1016/j.actpsy.2026.106760