I am now carry on my Ph.D. project time=net.work along with this website. The main purpose of the research project is to find out the relashionships between complex systems and transportation networks, as well as the most critical parts of the system according to topology and services. The first test case is the Berlin Transportation Network.

I'm working hard analysing the Berlin Transportation Network, which is very ‘busy’ ;-) but it works well. I’m analysing several spaces of services and some useful output formats in order to improve its reliability.

The German capital urban rail network consists of 9 U-Bahn (U), 16 S-Bahn (S) and 14 Regional Bahn (B) lines operating throughout the city and all over the Brandenburg region. Moreover it si connected with another network consisting of MetroBus and MetroTram lines. These elements have been defined as Layers, because they belong to an infrastructural level. All lines have been implemented in the tool as an input data (nodes = stations, edges = connections) along with their scheduled travel times and frequencies available from common timetables.

The tool built the necessary adjacent and weighted matrix A and T. Therefore all the networks have been characterised both topologically and related with services.

Pictures on this section are only some time=net.work outputs about the analyses taken on the whole transportation network of Berlin. They are related to the so called Centrality Measures. In particular they represent the shortest time/frequency paths between every pair of nodes in the network in a space called "of changes", representing the amount of direct connections between stations.

Every line represents a direct connection between Bus, Tram, U-bahn, S-bahn and Regional bahn network. This graph has been taken using time=net.work data and Yed, a freeware tool able to visualize graphs.

The analysis has to take into account the drop of efficiency related to travel times and frequencies according to the fraction of the nodes removed, for each infrastructural layer and space of service. Information Centrality allows to list the ranking of the nodes whose removal causes the maximum drop of performance (efficiency) in the network, for all layers in all spaces.

Railway Timetable Stability
(Opentrack)

One of the first Time=net.work application was a sort of timetable stability analysis. This study aimed at analysing the railway timetable robustness and reliability referred to a scheduled timetable and to a perturbed one affected by various kinds of failures, by means of intensive synchronous micro-simulation models of the network using of OpenTrack software. This tool, developed by the ETH in Zürich, simulates the run of trains on the modelled network, their conflicts, various kinds of block systems and all the remaining railway circulation characteristics.

Services could be delayed because of several causes: this new approach tries to define a new perturbed network by uncertain travel times, to analyse the stability of a complex weighted network compared with typical topological small world properties by means of an extended definition of time-based network characteristics, like Compactness (Lamanna, Longo et al. 2005). The Timetable Service Network tries to help the analysis of a new level of robustness of the timetable, related to network stability.

The so called Timetable Service Network is a new kind of graph structure which analyse both the weighted characteristics and the topology of different spaces of services in a railway network.

More information coming soon.