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Found 6674 publications
Comrades in theory, outsiders in practice: Cuban and Polish workers in the Kádár era in Hungary
Publication Name: Labor History
Publication Date: 2025-01-01
Volume: Unknown
Issue: Unknown
Page Range: Unknown
Description:
This study examines the political, ethnic, and social dimensions of transnational guest worker migration to Hungary during the late Kádár era, with a focus on Cuban and Polish workers. The research explores whether an institutionalized form of exploitation ‒ resembling colonial oppression ‒ emerged under state socialism despite official ideological commitments to racial equality. It also considers whether the socialist rhetoric of international solidarity was compatible with the realities of ethnic hierarchy and exclusion. Drawing on international and domestic literature, archival documents, statistical data, press sources, and focus group interviews, the study employs a primarily qualitative methodology to analyze the lived experiences of guest workers. The findings suggest that a form of socialist-style colonial exploitation was reproduced, especially in the case of Cuban workers, and that a complex mix of latent ethnic bias and overt national stereotypes shaped efforts to integrate guest workers. Finally, the research identifies key patterns that influence the acceptance or rejection of culturally distinct labor migrants and examines the broader ideological and social contradictions that these dynamics reveal.
Open Access: Yes
Transfer Learning-Based Steering Angle Prediction and Control with Fuzzy Signatures-Enhanced Fuzzy Systems for Autonomous Vehicles
Publication Name: Symmetry
Publication Date: 2024-09-01
Volume: 16
Issue: 9
Page Range: Unknown
Description:
This research introduces an innovative approach for End-to-End steering angle prediction and its control in electric power steering (EPS) systems. The methodology integrates transfer learning-based computer vision techniques for prediction and control with fuzzy signatures-enhanced fuzzy systems. Fuzzy signatures are unique multidimensional data structures that represent data symbolically. This enhancement enables the fuzzy systems to effectively manage the inherent imprecision and uncertainty in various driving scenarios. The ultimate goal of this work is to assess the efficiency and performance of this combined approach by highlighting the pivotal role of steering angle prediction and control in the field of autonomous driving systems. Specifically, within EPS systems, the control of the motor directly influences the vehicle’s path and maneuverability. A significant breakthrough of this study is the successful application of transfer learning-based computer vision techniques to extract respective visual data without the need for large datasets. This represents an advancement in reducing the extensive data collection and computational load typically required. The findings of this research reveal the potential of this approach within EPS systems, with an MSE score of 0.0386 against 0.0476, by outperforming the existing NVIDIA model. This result provides a 22.63% better Mean Squared Error (MSE) score than NVIDIA’s model. The proposed model also showed better performance compared with all other three references found in the literature. Furthermore, we identify potential areas for refinement, such as decreasing model loss and simplifying the complex decision model of fuzzy systems, which can represent the symmetry and asymmetry of human decision-making systems. This study, therefore, contributes significantly to the ongoing evolution of autonomous driving systems.
Open Access: Yes
DOI: 10.3390/sym16091180
Analyzing Energy Efficiency and Battery Supervision in Electric Bus Integration for Improved Urban Transport Sustainability
Publication Name: Sustainability Switzerland
Publication Date: 2024-09-01
Volume: 16
Issue: 18
Page Range: Unknown
Description:
Addressing the critical challenge of reducing local emissions through the electrification of urban public transport, this research specifically focuses on integrating electric buses. The primary objectives are to evaluate energy efficiency and ensure battery cell supervision. Introducing electric buses plays a significant role in reducing emissions, contributing to more sustainable urban transport systems. However, this transition introduces a set of new challenges, including the complexities of electric charging logistics, the establishment of new consumption standards, and the intricate relationships between distance traveled, ambient temperature, passenger load, and battery health. Methodologically, this study collects and examines factors impacting energy consumption, including external temperatures, bus conditions, road conditions, and driver behavior. By analyzing these variables, a baseline for actual consumption can be established, allowing for the calculation of an energy balance to identify energy inefficiencies. This enables the optimization of route planning, the strategic selection of stops, and the efficient scheduling of charging times, along with ensuring the proper scaling of the bus battery system. This study found that energy consumption peaked at 116.73 kWh/100 km in the lowest temperature range of −5 °C to 0 °C. Consumption decreased significantly with rising temperatures, dropping by 25 kWh between 5 °C and 10 °C and by an additional 10 kWh between 10 °C and 15 °C. Beyond 20 °C, variations were more influenced by route and driving style than by temperature. Route and driver variability significantly influenced energy consumption, with up to threefold differences across routes due to factors such as road type and traffic volume. Additionally, there was a 31.85% difference between the most and least efficient drivers, highlighting the critical impact of driving style. Furthermore, this study explores the assessment of battery systems through cell-level diagnostics to detect potential faults. Considering that buses are equipped with significantly more batteries than typical electric vehicles, detecting and localizing faults at the cell level is crucial to avoid the substantial costs and environmental impact associated with replacing large battery systems. Utilizing the results of this research and the applied examination methods, it is possible to enhance energy efficiency and extend battery life, thereby contributing to the development of more sustainable and cost-effective urban transport solutions.
Open Access: Yes
DOI: 10.3390/su16188182
Intelligent Fuzzy Traffic Signal Control System for Complex Intersections Using Fuzzy Rule Base Reduction
Publication Name: Symmetry
Publication Date: 2024-09-01
Volume: 16
Issue: 9
Page Range: Unknown
Description:
In this study, the concept of symmetry is employed to implement an intelligent fuzzy traffic signal control system for complex intersections. This approach suggests that the implementation of reduced fuzzy rules through the reduction method, without compromising the performance of the original fuzzy rule base, constitutes a symmetrical approach. In recent decades, urban and city traffic congestion has become a significant issue because of the time lost as a result of heavy traffic, which negatively affects economic productivity and efficiency and leads to energy loss, and also because of the heavy environmental pollution effect. In addition, traffic congestion prevents an immediate response by the ambulance, police, and fire brigades to urgent events. To mitigate these problems, a three-stage intelligent and flexible fuzzy traffic control system for complex intersections, using a novel hybrid reduction approach was proposed. The three-stage fuzzy traffic control system performs four primary functions. The first stage prioritizes emergency car(s) and identifies the degree of urgency of the traffic conditions in the red-light phase. The second stage guarantees a fair distribution of green-light durations even for periods of extremely unbalanced traffic with long vehicle queues in certain directions and, especially, when heavy traffic is loaded for an extended period in one direction and the short vehicle queues in the conflicting directions require passing in a reasonable time. The third stage adjusts the green-light time to the traffic conditions, to the appearance of one or more emergency car(s), and to the overall waiting times of the other vehicles by using a fuzzy inference engine. The original complete fuzzy rule base set up by listing all possible input combinations was reduced using a novel hybrid reduction algorithm for fuzzy rule bases, which resulted in a significant reduction of the original base, namely, by 72.1%. The proposed novel approach, including the model and the hybrid reduction algorithm, were implemented and simulated using Python 3.9 and SUMO (version 1.14.1). Subsequently, the obtained fuzzy rule system was compared in terms of running time and efficiency with a traffic control system using the original fuzzy rules. The results showed that the reduced fuzzy rule base had better results in terms of the average waiting time, calculated fuel consumption, and CO2 emission. Furthermore, the fuzzy traffic control system with reduced fuzzy rules performed better as it required less execution time and thus lower computational costs. Summarizing the above results, it may be stated that this new approach to intersection traffic light control is a practical solution for managing complex traffic conditions at lower computational costs.
Open Access: Yes
DOI: 10.3390/sym16091177
Tribological investigation of the effect of nanosized CuO and TiO2 on a base oil containing Komad 323 dispersant
Publication Name: Jurnal Tribologi
Publication Date: 2024-09-01
Volume: 42
Issue: Unknown
Page Range: 103-128
Description:
This article investigates the impact of copper(II) oxide (CuO) and titanium dioxide (TiO2 ) nanoparticles in Group III base oil with 8 wt% Komad 323 dispersant. Nanoparticles underwent ethyl oleate surface modification. Tribological properties were assessed using a linear oscillating tribometer, continuously monitoring static friction. Friction integral values were derived from extensive data acquisition. Wear analysis employed digital optical and confocal microscopy, complemented by scanning electron microscopy for wear-type characterization and energy-dispersive X-ray spectroscopy for additive quantification in the wear track. Results indicate CuO nanoparticles' poor compatibility with Komad 323, resulting in increased friction (2-13%) and substantial wear reduction (39-50%) at low CuO concentrations (≤0.3 wt%). Higher concentrations (≥0.4 wt%) reduced friction (21-35%) but led to surface fatigue and increased wear rates. Elemental composition analysis of the wear track revealed that the surface contains 1.43-3.17 norm.wt% copper. Conversely, TiO2 in synergy with the dispersant, formed a boundary layer, exhibiting lower friction by 11-14%. TiO2 formed a high wear resistance boundary layer at titanium concentrations of 0.33-0.39 norm.wt%, which resulted in 44% wear volume reduction. Applying both nanoparticles reduced the wear scar diameter of the test specimens by 3-12%.
Open Access: Yes
DOI: DOI not available
Learning generalized weighted relevance aggregation operators using levenberg-marquardt method
Publication Name: Proceedings Sixth International Conference on Hybrid Intelligent Systems and Fourth Conference on Neuro Computing and Evolving Intelligence His Ncei 2006
Publication Date: 2006-12-01
Volume: Unknown
Issue: Unknown
Page Range: Unknown
Description:
We previously introduced the generalized Weighted Relevance Aggregation Operators (WRAO) for hierarchical fuzzy signatures. WRAO enhances the ability of the fuzzy signature model to adapt to different applications and simplifies the learning of fuzzy signature models from data. In this paper we overcome the practical issues which occur when learning WRAO from data. This paper discuss an algorithm for learning WRAO using the Levenberg-Marquardt (LM) method, which is one of the most sophisticated and widely used gradient based optimization method. Also, this paper shows the successful results of applying the proposed algorithm to extract WRAO for two real world problems namely High Salary Selection and SARS Patient Classification. © 2006 IEEE.
Open Access: Yes
Power Injection Method-based Evaluation of the Effect of Binding Technique on the Coupling Loss Factors and Damping Loss Factors in Statistical Energy Analysis Simulations
Publication Name: Manufacturing Technology
Publication Date: 2021-01-01
Volume: 21
Issue: 4
Page Range: 544-558
Description:
Measurement results on the Damping Loss Factor (DLF) and Coupling Loss Factor (CLF) between two steel plates is presented for 19 different junction types. The junctions involve joining technologies, such as line welding, point welding, bolting, riveting, gluing or their combinations, and with varying spacing between the junction points and the angle between the plates. From the measurement results, the DLF and CLF values were calculated by the Power Injection Method for the purposes of being applied in Statistical Energy Analysis simulations. Four excitations were applied at each subsystem by impact hammer, while the response was recorded at sixteen response points at each subsystem. The measured CLF values were compared to each other from various aspects. Data were compared to the results obtained from SEA simulations by using the built-in analytical formulas. In general, good comparison was observed, although the results appeared to be somewhat dependent on the frequency band. Finally, it was examined whether replacing the DLF values with data obtained for an uncoupled flat plate, as well replacing the CLF values with data from analytical formulas leads to acceptable accuracy of the simulation results.
Open Access: Yes
Influence of local porosity on the mechanical properties of direct metal laser-sintered 1.2709 alloy
Publication Name: Strojniski Vestnik Journal of Mechanical Engineering
Publication Date: 2020-01-01
Volume: 66
Issue: 6
Page Range: 351-357
Description:
Powder bed metal printing has demonstrated its potential for the direct manufacturing of complex parts. It has great flexibility compared to conventional manufacturing. There are also some difficulties and problems, e.g., because the process stops during production. When the process is restarted, the first layer may be thicker due to technological limitations. In this paper, the effects caused by the presence of these thicker layers were investigated. The possibility of re-melting the layers to reduce porosity were also analysed. A tool steel powder grade 1.2709 was used to produce samples with an increased thickness of melted layers.
Open Access: Yes
NREM parasomnia-related behaviors and adverse childhood experiences
Publication Name: Sleep Medicine
Publication Date: 2024-09-01
Volume: 121
Issue: Unknown
Page Range: 365-369
Description:
Purpose: To assess the prevalence, types, sociodemographic factors, and reported dangerous activities of sleep-related behaviors likely representing NREM parasomnia episodes, as well as their association with adverse childhood experiences in Hungary. Methods: Cross-sectional survey of 1000 adults (aged ≥18 years) representing the Hungarian population, using a non-probability quota sampling with a random walk method and a structured face-to-face interview. A multi-criterion weighting procedure was applied to correct bias along the main sociodemographic variables to the data available. Binary logistic regression estimated the odds of NREM parasomnia-related behaviors associated with sociodemographic factors and adverse childhood experiences. Results: The prevalence of NREM parasomnia-related behaviors was 2.7 %, and self-reported sleep-eating was 0.1 % of the population (4.6 % of parasomnia-like activities). For middle-aged adults, the odds of sleep ambulation were significantly lower than for younger adults (OR 0.3; P = 0.03). A participant's family occurrence of reported parasomnia-like activity increased their odds of having it by more than 7 times (OR 7.1; P < 0.001). Nine participants out of those 27 people reporting NREM parasomnia-related behavior episodes, reported childhood adverse experiences, increasing the odds of parasomnia-related behavior by more than six times (OR 6.2; P < 0.001) compared to those not reporting it. Conclusion: This is the first population survey in Hungary on adult sleep-related behaviors likely representing NREM parasomnia episodes and the potential association with childhood traumatic events preceding them. The related dangerous behaviors call for safety measures and prevention. The significant association between adverse childhood events and NREM parasomnia-related behaviors needs further analysis.
Open Access: Yes
