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, and from 55.84 to 23.40 in the congested regime, where R2 rises from 0.8777 to 0.9785. Stopped fraction therefore provides a practical diagnostic for congestion states omitted from accumulation-only MFD representations.
In this study was numerically assessed electromagnetic exposure from a 2.4 GHz wireless communication system integrated into a motorcycle helmet. Using CST Studio Suite and an anatomically realistic human head model, the localized SAR were evaluated averaged over 10 g of tissue for five helmet shell materials at transmitter powers from 1 mW to 1 W. At 100 mW, polyimide produced the highest SAR (approximately 1.47 W/kg), whereas the carbon fibre produced the lowest (approximately 0.94 W/kg). All investigated configurations remained below the ICNIRP (International Commission on Non-Ionizing Radiation Protection) localized exposure limit of 2 W/kg for operating powers up to 100 mW, while higher-power scenarios exceeded this limit. The results demonstrate the importance of transmitter power, antenna placement, and helmet material properties for the electromagnetic safety of smart motorcycle helmets.
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%. These results show the suitability of the architecture chosen for bidirectional energy storage systems and grid connected energy management, renewable energy integration, and electric vehicle charging and V2G applications.
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 = -0.275). The SEM path coefficients ranged 0.597-0.652; DEA scores ranged 0.87-0.94.
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 in the context of possible future mixed civil-military operations and national security interests.
