Communications - Scientific Letters of the University of Zilina - Online first
Functional Safety-Oriented Risk Analysis of Heavy Vehicle Platooning
Luboš Mikula, Jan Famfulík
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.015 
In this paper is presented platooning as a promising approach to reduce the greenhouse gas emissions, fuel consumption, and operation costs in heavy traffic. Attention is given to a risk assessment of vehicle-to-vehicle (V2V) communication in the context of ISO 26262, Edition 2: Road vehicles - Functional safety. [ISO 26262-2 2018] The analysis focuses on safety-related hazards associated with convoy driving of heavy vehicles, utilizing the principles of functional safety. It applies hazard analysis and risk assessment (HARA) to classify potential risks according to their severity, exposure, and controllability. Automotive safety integrity level (ASIL)...
Optimizing Combustion Process: The Impact of Flame Zone Air Supply on Emissions and Performance in Pellet Boiler
Alexander Backa, Nikola Čajová Kantová, Peter Hrabovský, Pavol Belány, Róbert Cibula, Sławomir Sładek
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.016
Biomass combustion is a widely used renewable option for a small-scale heat and power, but incomplete burnout and pollutant formation remain challenges in boilers without optimized air staging. In this study, is investigated how controlled transport of air into the flame zone, implemented with an auxiliary tertiary system, affects performance and emissions in a bottom-fed pellet boiler. Tests were performed at constant fuel feed and primary/secondary airflow, with tertiary air varied between 0 and 15.8 m3/h. An airflow of about 8.9 m3/h proved optimal, giving the highest thermal output, a more uniform temperature distribution, and a nearly twentyfold...
Enhanced Harris Hawk Multi-Objective Optimization Algorithm for Cognitive Radio-Vehicular Ad Hoc Networks
Md. Asif Hossain
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.017
In this paper is presented an Enhanced Harris Hawk Multi-Objective Optimization (EH-HHO) algorithm for joint spectrum allocation, interference mitigation, and energy efficiency optimization in Cognitive Radio–Vehicular Ad Hoc Networks (CR-VANETs). EH-HHO integrates adaptive exploration, dynamic switching, and crowding-distance preservation to avoid premature convergence and obtain well-distributed Pareto-optimal solutions. Extensive simulations, using the SUMO–OMNeT++, VEINS/ns-3, and hardware-in-the-loop experiments, show superior spectrum utilization, energy savings, and convergence speed compared to NSGA-II and MOPSO. Statistical validation...
Assessment of Vehicular Passenger Occupancy and Its Effect on Los
Rashmi Ranjan Samal, Kundan Samal, Sitansu Kumar Das, Satya Ranjan Samal, Malaya Mohanty
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.018
The expansion of infrastructure in developing countries have led to a surge in car ownership. Although cars offer greater safety, their less passenger occupancy has contributed to reduced level of service (LOS). The present study was aimed to investigate the effect of passenger occupancy of various modes of transport on LOS. Detailed on-field surveys, including video recordings and questionnaires have been used to collect data, which is subsequently analyzed. The study findings suggest that a huge improvement in LOS and congestion can be achieved if public transportation is used more. Even usage of 3Ws and 2Ws can reduce congestion compared to usage...
Development of a Factor Analysis Model for Assessing the Technical Readiness of the Railway Rolling Stock
Razim Bayramov, Ilham Huseynov, Israil Elyazov, Shamil Heydarov
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.019
In this study was investigated the Technical Readiness Coefficient (TRC) of railway rolling stock and associated technical systems. The primary objective was to identify and analyze the key factors influencing TRC and to develop a structured methodology for the factor analysis of railway technical readiness. The research methodology includes the selection of principal determinants, construction of a descriptive analytical model, processing of empirical operational data, and application of regression and correlation analyses. Empirical and theoretical approaches were employed, using statistical data, maintenance schedules, normative tables, and computational...
Maritime Freight Cost Shocks and Sme Financial Performance in the Visegrad Region during and after COVID-19
Aleksandar Alačkov, Michal Červinka
Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.020
In this paper is analysed how the maritime freight costs fluctuations (2020-2024) affected the small and medium sized enterprises (SMEs) across the Visegrad Group using firm-level panel data and fixed-effects regressions. Four financial indicators were examined: turnover, gross margin, inventory stock, and cost of goods sold (COGS), with the Shanghai containerized freight index (SCFI) as the key explanatory variable. Higher freight costs are associated with increased turnover, inventories, and COGS, and with reduced gross margins, though the within-firm explanatory power is low. Overall, shipping price shocks leave measurable but modest effects on...