Slavko Vesković

A fuzzy Petri net model to estimate train delays

Abstract Even with the most accurate timetable, trains often operate with delays. The running and waiting times for trains can increase unexpectedly, creating primary delays that cause knock-on delays and delays for other trains. The accurate estimation of train delays is important for creating timetables, dispatching trains, and planning infrastructures. In this work, we proposed a fuzzy Petri net (FPN) model for estimating train delays. The FPN model with characteristics of hierarchy, colour, time, and fuzzy reasoning was used to simulate traffic processes and train movements in a railway system. The trains were coloured tokens , the track sections were termed places , and discrete events of train movement were termed transitions . The train primary delays were simulated by a fuzzy Petri net module in the model. The fuzzy logic system was incorporated in the FPN module in two ways. First, when there were no historical data on train delays, expert knowledge was used to define fuzzy sets and rules, transforming the expertise into a model to calculate train delays. Second, a model based on the Adaptive Network Fuzzy Inference System (ANFIS) was used for systems where the historical data on train delays were available (from detection systems or from the train dispatcher’s logs). The delay data were used to train the neuro-fuzzy ANFIS model. After the results of the fuzzy logic system were verified, the ANFIS model was replicated by a fuzzy Petri net. The simulation was validated by animating the train movement and plotting the time-distance graph of the trains. Results of the simulation were exported to a database for additional data mining and comparative analysis. The FPN model was tested on a part of the Belgrade railway node.

Heuristic Based Real-Time Train Rescheduling System

This article deals with the problem of train rescheduling on a railway network. Starting from a defined network topology and initial timetable, the article considers a dynamic train rescheduling in response to disturbances that have occurred. The train rescheduling problem was mapped into a special case of the job shop scheduling problem and solved by applying a constraint programming approach. To improve the time performance of available constraint programming tool and to satisfy a selected objective function, a combination of three classes of heuristics are proposed: bound heuristics, separation heuristics, and search heuristics. Experimental evaluation of the implemented software in Belgrade railway dispatching area indicates that the proposed approach is capable of providing the support to a real-life operational railway control. In our solution, the dispatcher has the possibility of choosing the most suitable optimization criterion from the set of seven available ones.

Schema on read modeling approach as a basis of big data analytics integration in EIS

ABSTRACT Big Data analysis is the process that can help organizations to make better business decisions. Organizations use data warehouses and business intelligence systems, i.e. enterprise information systems (EISs), to support and improve their decision-making processes. Since the ultimate goal of using EISs and Big Data analytics is the same, a logical task is to enable these systems to work together. In this paper we propose a framework of cooperation of these systems, based on the schema on read modeling approach and data virtualization. The goal of data virtualization process is to hide technical details related to data storage from applications and to display heterogeneous data sources as one integrated data source. We have tested the proposed model in a case study in the transportation domain. The study has shown that the proposed integration model responds flexibly and efficiently to the requirements related to adding new data sources, new data models and new data storage technologies.

B2B integration of rail transport systems in cloud computing environment

This paper proposes the Business-to-Business (B2B) model in the field of railways, based on combining information integration and portal integration in the cloud computing technological environment. Information integration is carried out in a common SQL Azure database. The portal integration is enabled with Windows Azure hosted service. The proposed model is implemented in a case study of integration of information systems that are used for the railroad crossings management in the Serbian Railways.

SOA architecture for complying with EU railway timetable data exchange format

When applying EU standards to the Serbian railway system, one of the major prerequisites is achieving interoperability with EU railway system. This paper describes a Web service for effortless timetable data exchange based on European Railway Agency implementation guide. The implementation details of the actual railway timetable formats and the corresponding software architecture are described, confirming advantages of the SOA approach when compared to other existing solutions in this area.