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Found 6342 publications

A combined fuzzy and least squares method approach for the evaluation of management questionnaires

Dalia Susniene Ojaras Purvinis Ĺaszĺo T. Ḱoczy

Publication Name: Studies in Computational Intelligence

Publication Date: 2020-01-01

Volume: 819

Issue: Unknown

Page Range: 157-165

Description:

A set of answers to questions to employees of various companies in Lithuania may refer to various positive and negative aspects of the attitudes of employees. These are called Organizational Citizenship Behavior (positive) and Counterproductive Work Behavior (negative). The components in the answers may be grouped by expert knowledge, and by statistical analysis and, according to these approaches, based on expert domain knowledge by management specialists, fuzzy signature structures describing the mutual effects of single elements in the questionnaire may be created. There are some slight differences between the two results, that indicate that expert knowledge is sometimes not objective. An additional step applying hybrid Generalised Reduced Gradient algorithm and Genetic Evolutionary Algorithm for heuristic optimization of the aggregation parameters in the Fuzzy Signatures reveals a final model according to the responses. These latter results raise some new questions, including the idea of the use of undeterministic graphs, thus resulting in Fuzzy Fuzzy Signatures. The method could be applied to other similar multicomponent vague data pools.

Open Access: Yes

DOI: 10.1007/978-3-030-16024-1_20

Investigation of Track Gauge and Alignment Parameters of Ballasted Railway Tracks Based on Real Measurements Using Signal Processing Techniques

Péter Bocz Szabolcs Fischer György Terdik Ákos Vinkó Nándor Liegner

Publication Name: Infrastructures

Publication Date: 2023-02-01

Volume: 8

Issue: 2

Page Range: Unknown

Description:

This paper deals with the time-frequency characteristic analysis for track geometry irregularities using field data recorded by a comprehensive track inspection train. The parameters of the track gauge and the left and right rail alignment are considered to identify their characteristic wavelengths and the locations of their waveforms. In addition to the conventional time and frequency domain analysis, auto-adaptive signal decomposition techniques are used on four pre-selected track sections. During the time series analysis of the track gauge, the cumulative difference from the mean value is calculated, which makes it possible to distinguish the track section constructed with non-standard initial track gauges. The sensitive wavelengths of the track irregularities are obtained from the proper allocation of wavelength ranges in the Fourier Amplitude Spectrum of the original signal and the Fourier transform of the components detected by the Variational Mode Decomposition. This analysis can elucidate the wavelengths and positions of track irregularities that affect vehicle responses.

Open Access: Yes

DOI: 10.3390/infrastructures8020026

Environmental influence on the fine structure of dummy-head HRTFs

András Illényi Gyorgy Wersenyi

Publication Name: Forum Acusticum Budapest 2005 4th European Congress on Acustics

Publication Date: 2005-12-01

Volume: Unknown

Issue: Unknown

Page Range: 2529-2534

Description:

The directional filtering of the outer ears is a significant step during the evaluation of spatial information. A computer-controlled dummy-head measurement system was developed to measure the HRTFs in huge amount and with increased spatial resolution. Effects and common properties of objects near the head (glasses, hair, baseball cap) were measured. Changes in the HRTFs due to the acoustical environment will be presented as function of frequency and azimuth for different elevations on 2D polar diagrams. Differences of about 1 dB are evaluated in the fine structure of the measured HRTFs and conclusions are drawn for the relevance of HRTF reproduction in binaural synthesis.

Open Access: Yes

DOI: DOI not available

The configurable digital cellular neural - Hopfield network

Tamás Zeffer Timót Hidvégi

Publication Name: Ines 2006 10th International Conference on Intelligent Engineering Systems 2006

Publication Date: 2006-12-01

Volume: Unknown

Issue: Unknown

Page Range: 160-164

Description:

A configurable Artificial Neuron Network that is capable of establishing both the emulated digital Cellular Neural Network (CNN) and the Hopfield Network is described. The configurable neural network is designed with the method of modularity where each module is a three weighted input neuron. The network can be optionally large limited only by the gate number available on a chip. Also, the network is reconfigurable during operation. © 2006 IEEE.

Open Access: Yes

DOI: DOI not available

Traffic-flow analysis for fast performance estimation of communication systems

Gábor Lencse

Publication Name: Journal of Computing and Information Technology

Publication Date: 2001-01-01

Volume: 9

Issue: 1

Page Range: 15-27

Description:

The traffic-flow analysis (TFA) is a promising method for the performance estimation of communication systems. TFA produces approximate results with much less computation (that is, much faster) than discrete-event simulation of the system. In the first step, TFA distributes the traffic in units of properly chosen size using the actual routing algorithm of the network. In the second step, TFA adjusts the time distribution of the traffic according to the finite capacities of the network. It was found that the results of TFA approximate the results of the analytical method well.

Open Access: Yes

DOI: 10.2498/cit.2001.01.02

Axial strength of back to back cold formed steel short channel sections with unstiffened and stiffened web holes

Ardalan B. Hussein F. Papp

Publication Name: Scientific Reports

Publication Date: 2025-12-01

Volume: 15

Issue: 1

Page Range: Unknown

Description:

The increasing adoption of back-to-back built-up cold-formed steel (CFS) channel columns in construction is attributed to their lightweight nature, versatility in shape fabrication, ease of transportation, cost efficiency, and enhanced load-bearing capacity. Additionally, the incorporation of web openings facilitates the integration of electrical, plumbing, and heating systems. These built-up sections are widely utilized in wall studs, truss elements, and floor joists, with intermediate screw fasteners strategically positioned at regular intervals to prevent the independent buckling of channels. Based on 18 experimental tests, this study demonstrates an excellent correlation between finite element analysis and the experimental results, confirming the accuracy of geometrically and materially nonlinear finite element modeling in predicting the axial buckling strength of built-up short columns. Furthermore, the design standards of the American Iron and Steel Institute and Australian/New Zealand Standards were found to underestimate the axial load capacity by approximately 12.5%. The primary objective of this research is to investigate the influence of various hole configurations, both with and without stiffeners, on the axial performance of built-up short CFS channel columns. A total of 180 finite element models were developed, examining four different unstiffened and edge-stiffened hole configurations, validated against experimental results from plain webs. The findings reveal that web holes and edge stiffeners significantly impact axial load-bearing capacity, while the specific shape of the openings has a negligible effect. Specifically, introducing a hole at the centroid of each web results in an approximate 8.5% reduction in axial load capacity in the absence of edge stiffening. However, the incorporation of stiffeners around the perforations mitigates this reduction and enhances both structural efficiency and load-bearing capacity. These results highlight the critical role of edge stiffening in optimizing the structural performance of perforated built-up CFS columns.

Open Access: Yes

DOI: 10.1038/s41598-025-15992-9

Bibliometric Evidence on the Trend and Future Direction of the Research on Textile Coloration with Natural Sources

Aminoddin Haji Mohammad Tajul Islam Md Reazuddin Repon Md Abdullah Al Mamun Md Himel Mahmud

Publication Name: Coatings

Publication Date: 2023-02-01

Volume: 13

Issue: 2

Page Range: Unknown

Description:

Synthetic dyes used for the coloration of textile goods are not readily biodegradable and are a major concern for water pollution. Nature has abundant sources of potential colorants for textile applications. There are many challenges in textile coloration using natural dyes and pigments, and significant research efforts are currently put into replacing synthetic textile dyes successfully. In order to gain insight into the future trajectory of dyeing research utilizing natural colorants, a bibliometric analysis from 1990 to 2021 using the Science Citation Index Expanded database was conducted. The analysis focused on how well the publication performed in terms of outputs and citations annually, mainstream journals, Web of Science categories, top universities, top nations, research trends, and hotspots. An overview of the most frequently used keywords derived from terms in the article title analysis, authors’ keyword analysis, and KeyWords Plus analysis served as the foundation for determining current research goals and future trends. The findings indicated that no noteworthy research on this topic was conducted in the final decade of the previous century but that it did begin to get the attention of scholars in the first decade of this century. The use of natural dyes in industry has significantly expanded during the past ten years. “Fastness” is the interest point that has received the most attention. Mordants, or environmentally friendly extraction techniques such as ultrasonic, gamma irradiation, etc., represent the future of this research area. On the other hand, ultraviolet protection and antibacterial or antimicrobial properties are becoming more and more popular in the field of textile dyeing research using natural colorants.

Open Access: Yes

DOI: 10.3390/coatings13020413

The method of asymptotic expansion for plate problem in the linear theory of viscoelasticity

Lotfi Abdelhakim G. Y. Molnarka

Publication Name: ZAMM Zeitschrift Fur Angewandte Mathematik Und Mechanik

Publication Date: 2000-01-01

Volume: 80

Issue: 4 SUPPL. 2

Page Range: S391-S392

Description:

The method of asymptotic expansion originally developed for elasticity problems is generalized to linear viscoelastic problems. Three-dimensional, unsteady problems corresponding to a class of viscoelastic plates are considered. By employing the Laplace transform, the original problem is converted to an equivalent elastic problem, where the asymptotic expansion method is used. An application of this method to the Maxwell model is also presented.

Open Access: Yes

DOI: 10.1002/zamm.20000801467

Investigation of the Applicability of a Hybrid Foaming System in a Mixed Plastic Waste Matrix

V. A. Szabó Gabor Dogossy

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2025-09-04

Volume: 69

Issue: 3

Page Range: 215-223

Description:

In our research, we investigated the chemical foaming of mixed plastic waste granulate (VMHD) using a combination of endothermic and exothermic foaming agents. We found that increasing the exothermic foaming agent improved cell distribution but reduced flexibility and impact resistance. The highest porosity (30.04%) was achieved with 0.5% endothermic and 3.5% exothermic foaming agents. Our results indicate that the proper ratio of foaming agents is crucial for optimizing the mechanical properties of the material.

Open Access: Yes

DOI: 10.3311/PPme.40846