Communications - Scientific Letters of the University of Zilina - Online first
Modelling and Optimization of Hydrogen Fuel Systems in Railway Vehicles Using Data Analysis and Machine Learning
Oleksandra Shepel, Ján Dižo, Miroslav Blatnický, Martin Bučko
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.045 
Hydrogen fuel cell systems offer a zero-emission alternative to diesel-powered trains, combining high energy density with the potential for renewable energy integration. A hybrid data-driven modelling and optimization approach of improving the efficiency, reliability, and cost-effectiveness of hydrogen fuel systems for rail applications is developed in this research. Using operational and thermodynamic data from simulated and experimental sources, a predictive model of fuel cell performance based on non-linear regression and machine learning methods was developed. Results indicate that the data-driven model predicts system efficiency with a mean absolute...
Adapting D-Fmea to Increasing Product Complexity: A Study of Conventional and Mechatronic Shock Absorbers
Łukasz Rudolf, Marek Roszak, Lenka Kuchariková
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.046
The risk analysis is essential in product development, particularly as technical complexity increases. In this article the focus was on Design Failure Mode and Effects Analysis (D-FMEA) in the automotive industry. The conventional and electronically controlled shock absorbers as examples of a transition from a mechanical-hydraulic product to a more complex mechatronic system, are compared. In the study was considered how increasing complexity affects analysis boundaries, decomposition level, function description, interactions between components and subsystems, and the link between risk analysis and product validation. Based on industrial practice,...
Towards the Digital Twin-Enabled v2i Monitoring of Ship Power Plants under Real Operating Conditions
Andrii Holovan, Igor Gritsuk, Iryna Honcharuk, Olena Volska, Andrii L. Simanenkov, Artem A. Ivanov
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.047
In this paper is presented an ITS-oriented framework for monitoring and predictive assessment of ship power plants based on V2I communication and digital twin principles. The framework integrates onboard sensor data with environmental and operational information in a unified cyber-physical environment. A mathematical model and structured algorithm support state estimation, prediction, diagnostics, and decision-making under non-stationary conditions. The distributed architecture combines onboard systems, communication networks, and infrastructure-level processing. Validation using real operational data demonstrates that the framework captures variations...
Optimising Urban Traffic Flow through Green-Wave Signal Coordination: Effects on Delays, Fuel Consumption and Emissions in Baku
Mirhamid Baghirov, Heybatulla Ahmedov
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.048
In this study it was investigated how the traffic optimisation can reduce the environmental impact of urban transport. Traffic flows were modelled on a key urban road section, and traffic-light phases were optimised and synchronised to create smoother movement and reduce intersection delays. Data on traffic volume, delay time, fuel consumption and pollutant emissions were collected before and after the implementation. The results showed a 20-25% reduction in intersection delays, accompanied by an average of 15% decrease in CO2 emissions. Fuel consumption fell by 10% for cars and 15% for trucks. Traffic-light optimisation also improved the...
Comparative Analysis of the T1 Transit Procedure and TIR System: Institutional and Cost Efficiency Perspectives from Azerbaijan
Elvin Alirzayev, Nijat Karimov
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.049
The role and effectiveness of the T1 customs procedure in international transit transportation were examined in this study. It analyzes the legal framework, operational mechanism, and impact of the T1 procedure on logistics processes, while comparing its characteristics with the TIR system within the Common Transit (CT) framework. The findings demonstrate that the T1 procedure enhances customs control, reduces transit time and logistics costs, and strengthens risk management. Furthermore, the implementation of the New Computerised Transit System (NCTS) improves the transparency, traceability, and operational efficiency of transit operations, thereby...
Gender Differences in Visual Attention and Stated Preferences during Evaluation of Battery Electric Vehicles: An Exploratory Eye-Tracking Study
Viktória Cvacho, Radovan Madleňák, Alessandro Pagano, Edward Kozłowski
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.050
In this exploratory study were examined the gender differences in visual attention and stated preferences during the evaluation of battery electric vehicles (BEVs) using eye-tracking. Thirty-two participants (18 men, 14 women) viewed static images of the ten top-selling BEVs in Slovakia while eye movements were recorded across four predefined Areas of Interest (AOIs). Vehicle design attracted the greatest absolute dwell time in both groups. No gender difference reached conventional statistical significance (all p > 0.05), yet medium effect sizes were obtained for brand (d = 0.69), acceleration (d = 0.67), vehicle equipment (d = 0.60) and trunk capacity...
Synchronizing Public Transport Schedules with Genetic Algorithms: Choosing the Heuristic Parameters
Vitalii Naumov, Assyl Tazhmuratova, Ihor Taran, Yuliia Melnikova, Daniel Kapica
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.051
Synchronized timetables are crucial for public transportation, yet optimizing them remains complex. While Genetic Algorithms (GAs) address this challenge effectively, their success depends on parameter tuning. In this study was examined how the GA parameters affect schedule synchronization, using a stochastic simulation model to evaluate the fitness of alternative solutions. It is found that the larger population sizes improve solution quality, and higher crossover probabilities enhance overall performance. Conversely, increasing mutation rates or the number of attempted mutations reduces the algorithm’s ability to converge on optimal timetables....
OPERATIONAL FACTORS AND THEIR IMPACT ON SELECTION OF APPROACH SYSTEMS AT REGIONAL PUBLIC INTERNATIONAL AIRPORTS
Rostislav Stryk, Lenka Kontriková, David Mičulka
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.052
Regional public international airports undergo periodic modernization, including the modernization of air navigation and approach systems. In this paper is proposed a transferable decision-making framework based on the Analytic Hierarchy Process (AHP) for selecting approach systems at airports with potential mixed civil-military traffic. Its main contribution is an AHP-based procedure adapted to the operational and technical conditions of approach-system modernization. The procedure is demonstrated through a case study of Ostrava/Mosnov International Airport, assessing selected alternatives and their operational impacts on long-term airport development...
The Esg-Oriented Approaches to Developing a Sustainable Rail Freight Market: Methodology and Effectiveness Assessment
Bibizhan Aimagambetova, Olga Kisselyova, Roza Mussaliyeva, Yerzhan Karsybayev, Marzhan Chazhabayeva
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.053
In this paper, the sustainability of Kazakhstan's rail freight market was analyzed in the context of the influence of ESG (Environmental, Social, Governance) variables. The data used (secondary data 2018-2024) and the expert surveys (regression, SEM (Structural Equation Modelling), DEA (Data Envelopment Analysis)) revealed that ESG factors have a significant impact on performance (R² = 0.85), competitiveness (R² = 0.82), and stability (R² = 0.84). The most powerful factors were corridor efficiency (β = 0.421) and service quality (β = 0.370) with negative effects being energy consumption (β = -0.312) and emissions (β...
Stopped Fraction and Closure Failure in Congested Macroscopic Fundamental Diagrams: A Sumo-Based Simulation Study
Tomoo Noguchi
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.054
Congested macroscopic fundamental diagrams (MFDs) often display scatter since accumulation alone does not fully describe immobilization within stored traffic. In this paper, the stopped fraction, defined as the share of vehicles that are stopped or nearly stopped, is examined as a complementary macroscopic state variable. A compact analytical framework shows why accumulation-only closure can fail when stopped fraction varies at fixed accumulation. The mechanism is tested using the Simulation of Urban MObility (SUMO) platform on a stylized signalized grid. Adding stopped fraction reduces the root mean squared error (RMSE) from 41.32 to 18.79 overall,...
Evaluation and Experimental Validation of Power Converter Topologies for a Bidirectional Grid-Connected Battery Energy Storage System
Michal Praženica, Patrik Resutík, Slavomír Kaščák, Michal Prídala, Martin Kuchař
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.055
In this research is described the topology assessment, design, simulation, and experimental verification of bidirectional grid connected BESS. Several converter topologies were assessed based on the efficiency, power quality, bidirectional capability, electromagnetic compatibility, and ease of implementation. A bridgeless totem-pole PFC converter, together with bidirectional CLLLC resonant DC/DC converter, was chosen and implemented in 2 kW lab prototype. Experimental tests in both grid-to-battery and battery-to-grid modes yielded maximum power of 2.28 kW, a power factor of 1.0, total current harmonics of 1.43%, and maximum efficiency of around 96%....