Role discovery in node-attributed public transportation networks: the model description

Modeling public transport systems from the standpoint of the theory of complex networks is of great importance to improve their efficiency and reliability. An important task here is to analyze the roles of nodes and weighted links in the network, respectively modeling groups of public transport stops and their linking routes. In previous works, this problem was solved based on only topological and geospatial information about the presence of routes between stops and their geographical location which led to the problem of uninterpretability of the discovered roles. In this article, to solve the problem, the model additionally considers information about the social infrastructure around the stops and discovers topological, geospatial, and infrastructure roles jointly. The public transport system is modeled using a special weighted network — with node attributes where nodes are non-overlapping groups of stops united by geospatial location, node attributes are vectors containing information about the social infrastructure around stops, and weighted links integrate information about the distance and number of transfers in routes between stops. To identify the model, it is sufficient to use only open urban data on the public transport system. Role discovery for stops is carried out by clustering network nodes in accordance with their topological and attributive features. An extended model of the public transport system and a new approach to solving the problem of discovering the roles of stops, providing interpretability from the topological, geospatial and infrastructural points of view, are proposed. The model was identified on the open data of Saint Petersburg about metro stations, trolleybus and bus stops as well as organizations and enterprises around the stations and stops. Based on the data, balanced parameters for grouping stops, assigning link weights and constructing attribute vectors are found for further use in the role discovery task. The results of the study can be used to identify transport and infrastructure shortcomings of real public transport systems which should be considered to improve the functioning of these systems in the future.