A survey on future railway radio communications services: challenges and opportunities

Radio communications is one of the most disruptive technologies in railways, enabling a huge set of value-added services that greatly improve many aspects of railways, making them more efficient, safer, and profitable. Lately, some major technologies like ERTMS for high-speed railways and CBTC for subways have made possible a reduction of headway and increased safety never before seen in this field. The railway industry is now looking at wireless communications with great interest, and this can be seen in many projects around the world. Thus, railway radio communications is again a flourishing field, with a lot of research and many things to be done. This survey article explains both opportunities and challenges to be addressed by the railway sector in order to obtain all the possible benefits of the latest radio technologies

A new analytical approach to evaluate the critical-event probability due to wireless communication errors in train control systems

Wireless communication links tend to be employed more and more in safety-critical railway applications. Their safe use in an advanced train control system (TCS) is an issue that is addressed in this paper by characterizing the TCS service inter- ruption due to communication errors. More precisely, occurrence probabilities of single errors are first discussed. Then, we obtain probabilistic analytical expressions of several temporal conditions that lead to a TCS service interruption, here a train emergency braking (the critical event). The accuracy of this analytical ap- proach is proved when the results are compared with those given by a simulation approach with a Petri net model. Additionally, as the use case related to the “trains’ separation” is considered in this paper, an analytical evaluation process is proposed to discuss the tolerated time margins that can be fixed to limit the critical-event occurrence probability due to the wireless communication errors

Determining Intervention Fidelity from Chronological Field Notes

Intervention fidelity (IF) is a relatively recent methodological consideration in nursing research that refers to the adherent and competent behaviors by the interventionist in the delivery of the intervention as planned (Santacroce, Maccarelli, & Grey, 2004; Stein, Sargent, & Rafaels, 2007). Intervention fidelity is a major contributor to the internal validity of a study. When an intervention is delivered as prescribed, the inference that the outcome is caused by the intervention is supported. If intervention fidelity is low, the expected differences between intervention group and control group may not occur. Historically, researchers have used various recording devices [audio or video tapes] to gather data on intervention fidelity. However, concerns about privacy or disruption of the intervention as a result of taping may prevent this method from being used. Field notes written at the time of the delivery may be a solution. However, field notes have not been extensively tested as an alternative device. The purpose of this pilot study was to explore an alternative method of determining intervention fidelity using chronological field notes (CFNs) (Stein, et al., 2007; Waltz, Addis, Koerner, & Jacobson, 1993). Method: A secondary analysis using data from an intervention study that used chronological field notes was completed. A randomly selected sample of chronological field notes (N=181) written by interventionist nurses (N=20) were coded using the Collaborative Study Psychotherapy Rating Scale (CSPRS), a validated fidelity instrument used in similar studies. Results: The interrater reliability (IRR) on the CSPRS was excellent on adherence (IRR .95 and Cronbach alpha .97) and for the new competence scale, IRR .74 and Cronbach alpha .91. The results on the CSPRS were comparable to a study (Hill, 1992) that used traditional methods of transcribed audiotapes. This exploratory study provided support that an alternative methodological approach to determining intervention fidelity is feasible. Further research with a larger sample is needed to conclude with greater certainty that intervention fidelity can be determined using field notes.Doctor of Philosoph

Multi Objective Ant Colony Optimisation to obtain efficient metro speed profiles

[EN] Obtaining efficient speed profiles for metro trains is a multi- objective optimisation problem where energy consumption and travel time must be balanced. Automatic Train Operation (ATO) systems may handle a great number of possible speed profiles; hence optimisation algorithms are required find efficient ones in a timely manner. This paper aims to assess the performance of a particular meta-heuristic optimisation algorithm, a variation of the traditional Ant Colony (ACO) modified to deal with multi-objective problems with continuous variables: MOACOr. This algorithm is used to obtain efficient speed profiles in up to 32 interstation sections in the metro network of Valencia (Spain), and the convergence and diversity of these solution sets is evaluated through metrics such as Inverse Generational Distance (GD) and Normalised Hypervolume (NH). The results are then compared to those obtained with a conventional genetic algorithm (NSGA-II), including a statistical analysis to identify significant differences. It has been found that MOACOr shows a better performance than NSGA-II in terms of convergence, regularity and diversity of the solution. These results indicate that MOACOr is a good alternative to the widely used genetic algorithm and could be a better tool for rail operation managers trying to improve energy efficiency.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Spanish Ministry of Economy and Competitiveness grant number TRA2011-26602.Martínez Fernández, P.; Font Torres, JB.; Villalba Sanchis, I.; Insa Franco, R. (2023). Multi Objective Ant Colony Optimisation to obtain efficient metro speed profiles. Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit. 237(2):232-242. https://doi.org/10.1177/09544097221103351232242237

Aspekte der Verkehrstelematik – ausgewählte Veröffentlichungen 2013

Der vierte Band der Schriftenreihe Verkehrstelematik stellt die intermodalen Forschungsthemen und ihre praktischen Anwendungen der Professur für Verkehrsleitsysteme und -prozessautomatisierung an der Fakultät Verkehrswissenschaften „Friedrich List“ der Technischen Universität Dresden mit ausgewählten Veröffentlichungen des Jahres 2013 vor. Die Schwerpunkte der Forschungsarbeit liegen einerseits im Bereich der energieoptimalen Steuerung im Schienenverkehr und zugehörigen Fahrerassistenzsystemen, andererseits auf dem Verkehrsmanagement des Straßenverkehrs. Die energieoptimale Steuerung im Schienenverkehr wird mittels Fahrerassistenzsystemen nicht nur im Eisenbahnverkehr, beispielsweise auf den Zügen des Harz-Elbe-Express, sondern auch auf Straßenbahn- und U-Bahn-Fahrzeugen umgesetzt. Darüber hinaus werden die Methoden und Verfahren der energieoptimalen Steuerung im Rahmen von Ansätzen für ein modularisiertes Verkehrsmanagement bei Eisenbahnen verwendet. Das Verkehrsmanagementsystem der Stadt Dresden VAMOS bildet die Basis für den zweiten Forschungsschwerpunkt. Hierbei werden im vorliegenden Band einerseits Möglichkeiten untersucht, den Straßenverkehr mikroskopisch zu simulieren und dabei die Verkehrszustandsdaten des VAMOS einfließen zu lassen. Andererseits wird der Frage nachgegangen, in wie weit man anhand der im System vorhandenen Floating-Car-Daten Straßensperrungen sicher identifizieren kann. Zu beiden Forschungsschwerpunkten sind fünf weitere Artikel im Rahmen der vom Lehrstuhl organisierten internationalen Konferenz „3rd Models and Technologies for Intelligent Transportation Systems (3. MT-ITS)“ entstanden. Diese Beiträge sind im Konferenzband als dritter Band der vorliegenden Schriftenreihe Verkehrstelematik bereits erschienen