• TRANSPORT. SAFETY AND ECOLOGY. LOGISTICS AND MANAGEMENT

    AN APPLICATION OF A NETWORK SCIENCE TOOL FOR EXAMINING AND ANALYSING THE STRUCTURE AND TOPOLOGICAL PROPERTIES OF PUBLIC-TRANSPORT NETWORKS: A CASE STUDY

    Trans Motauto World, Vol. 3 (2018), Issue 2, pg(s) 78-83

    More than one century network science (NS) has been extensively used in numerous studies of different research fields, including public transport (PT). This work presents an application of a NS tool enabling to explore complex public-transport networks (PTNs). This tool explores networks for small-world, scale-free and random network characteristics, in a case study to examine and analyze, by using NS concepts, two PT systems – Washington DC’s Metro Network (WMN) and Oslo’s Metro Network (OMN). The performed analyses focused on the structure and the topological properties of the examined networks. As the networks have longer average path
    lengths, compared with random networks, and because of not being clustered, these metro networks demonstrated they are not small-world networks. The analyses also show that in contrast to the OMN the WMN has certain characteristics associated with scale-free networks; that is, a small number of highly connected nodes (hubs) and node degree distribution that can be represented by a power-law function. Nevertheless, it still cannot be considered as a pure scale-free network because of its empirical distribution which is better approximated by an exponential rather than a power-law function. The metro WMN cannot be considered a random network because of having hubs. Thus, it is concluded that the examined WMN is an evolving complex network.

  • MATHEMATICAL MODELLING OF TECHNOLOGICAL PROCESSES AND SYSTEMS

    MODELLING AND SIMULATION OF HIGH-FREQUENCY AUTONOMOUS PUBLIC-TRANSPORT SERVICE

    Mathematical Modeling, Vol. 2 (2018), Issue 2, pg(s) 73-80

    In this paper, a simulation model of the novel concept of autonomous vehicles is developed for public transport (PT) service. The model aims to serve PT planners as a tool enabling the simulation of a metro-like, high-frequency service with punctual autonomous vehicles running on exclusive lanes. The model was applied in a numerical example of a passenger bus, with different scenarios employed. The outcome of the simulation shows that characteristics of the modelled system are reproduced, with the following results: (i) highfrequency, metro-like PT service, with reduced passenger waiting time, (ii) reduced vehicle capacity with reduced average dwell time; (iii) the least number of unserved passengers, across all scenarios, and (iv) better utilisation of vehicle capacity (with fewer unserved passengers) achieved through a small decrease in vehicle frequency, which led to a negligible increase of the average passenger waiting times. In addition, the model allows us to examine the system’s behaviour under uncertainty, considering passenger arrivals and vehicle headways as random input variables with predefined probability distributions. The proposed model enables modellers not only to evaluate a system’s performance, but also to examine different working conditions and possible future scenarios.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    THE STRESS VARIATION BY CHANGING THE SUPPORTING POINT LOCATION IN THE MOTOR VEHICLE CLUTCH ASSEMBLEY

    Trans Motauto World, Vol. 2 (2017), Issue 6, pg(s) 230-234

    The diaphragm spring as one of the most important parts of the motor vehicles clutch assembly provides the compressive force on the pressure disk. This force is needed for generating friction between the coupling of the flywheel and the pressure disk and transmitting the torque from the engine to the transmission. Therefore the diaphragm spring is subjected to complex loads. The nominal stress for dimensioning the spring is the tangential stress, which is calculated by the terms of Almen and Laszlo. The aim of this research is analyzing the location of the diaphragm spring supporting points of the clutch assembly and its effect on the caused stresses by using the Finite Element Method.