Model predictive control of timed continuous petri nets

This thesis addresses the optimal control problem of timed continuous Petri nets. The theory of Model Predictive Control (MPC) is first discussed. Then continuous Petri nets (PN) are introduced as a powerful tool for modelling, simulation and analysis of discrete event/continuous systems. Their useful capabilities are studied. Finally, a macroscopic model based on PN as a tool for designing control laws that improve the behavior of traffic systems is given. The goal is to find an approach that minimizes the total delay of cars in an intersection by computing the switching sequence of the traffic lights. The simulation results show that by using an MPC strategy to handle the variability of traffic conditions, the total delay is dramatically reduced

Use of Petri Nets to Manage Civil Engineering Infrastructures

Over the last years there has been a shift, in the most developed countries, in investment and efforts within the construction sector. On the one hand, these countries have built infrastructures able to respond to current needs over the last decades, reducing the need for investments in new infrastructures now and in the near future. On the other hand, most of the infrastructures present clear signs of deterioration, making it fundamental to invest correctly in their recovery. The ageing of infrastructure together with the scarce budgets available for maintenance and rehabilitation are the main reasons for the development of decision support tools, as a mean to maximize the impact of investments. The objective of the present work is to develop a methodology for optimizing maintenance strategies, considering the available information on infrastructure degradation and the impact of maintenance in economic terms and loss of functionality, making possible the implementation of a management system transversal to different types of civil engineering infrastructures. The methodology used in the deterioration model is based on the concept of timed Petri nets. The maintenance model was built from the deterioration model, including the inspection, maintenance and renewal processes. The optimization of maintenance is performed through genetic algorithms. The deterioration and maintenance model was applied to components of two types of infrastructure: bridges (pre-stressed concrete decks and bearings) and buildings (ceramic claddings). The complete management system was used to analyse a section of a road network. All examples are based on Portuguese data

Simplifying the verification of simulation models through Petri net to FlexSim mapping

Simplifying the encoding of a simulation conceptual model representation reduces the number of errors that will be detected in the verification phase. In this paper, we present a mapping between Petri nets, a well-known formalism, and FlexSim, a well-known simulation tool. The proposal is illustrated through an example of how a model specified in a Petri net can be encoded easily, reducing the time needed to understand and verify the model. In the proposed methodology, the mapping must be defined at the initial stage of the encoding, starting from (in this case) a Petri net conceptual model, and ending at the encoding tool (FlexSim in this case). The main advantages of the proposed methodology are discussed.Peer ReviewedPostprint (author's final draft

Petri Nets Models for Analysis and Control of Public Bicycle-Sharing Systems

International audienc

Simulasi kinerja lalu lintas kendaraan tanpa awak di area perkotaan

Permasalahan transportasi perkotaan, khususnya di Jakarta, semakin memburuk. Kondisi itu dipersulit dengan keterbatasan lahan untuk membangun infrastruktur baru. Saat ini sedang dikembangkan berbagai teknologi untuk mengatasi permasalahan transportasi yang ada di perkotaan terutama masalah kemacetan yang sulit untuk diatasi. Sebagai bagian dari upaya untuk meningkatkan kualitas transportasi yang semakin rumit dengan tidak membangun infrastruktur baru, namun dalam penelitian ini ingin mengenalkan penggunaan kendaraan tanpa awak di lalu lintas perkotaan di Jakarta. Penelitian ini menggunakan pemodelan dan simulasi transportasi dengan menggunakan parameter lingkungan yang sebenarnya. Dengan penggunaan model Two fluid dapat menggambarkan waktu tempuh dan indikator kualitas lalu lintas pada jaringan lalu lintas. Tujuan yang ada dalam penelitian ini adalah untuk menganalisis kinerja lalu lintas kendaraan tanpa awak (Intelligent Autonomous Vehicle/IAV) yang akan dibandingkan dengan kendaraan konvensional dengan menggunakan simulasi lalu lintas SCANeR™studio. Kesimpulan yang didapat dari penelitian adalah kinerja lalu lintas kendaraan tanpa awak (IAV) di area perkotaan lebih baik dibandingkan kendaraan konvensional karena waktu tempuh lebih pendek dan parameter kualitas lalu lintas juga lebih baik yaitu : (1) IAV → n = 0.01, Tm = 2.24 min/km, kecepatan rata-rata = 13.61 km/h ; (2) Kendaraan konvensional → n = 0.03, Tm = 2.37 min/km, kecepatan rata-rata = 12.02 km/h

On analyzing the vulnerabilities of a railway network with Petri nets

Petri nets are used in this paper to estimate the indirect consequences of accidents in a railway network, which belongs to the class of the so-called transportation Critical Infrastructures (CIs), that is, those assets consisting of systems, resources and/or processes whose total or partial destruction, or even temporarily unavailability, has the effect of significantly weakening the functioning of the system. In the proposed methodology, a timed Petri ne<t represents the railway network and the trains travelling over the rail lines; such a net also includes some places and some stochastically-timed transitions that are used to model the occurrence of unexpected events (accidents, disruptions, and so on) that make some resources of the network (tracks, blocks, crossovers, overhead line, electric power supply, etc.) temporarily unavailable. The overall Petri net is a live and bounded Generalized Stochastic Petri Net (GSPN) that can be analyzed by exploiting the steady-state probabilities of a continuous-time Markov chain (CTMC) that can be derived from the reachability graph of the GSPN. The final target of such an analysis is to determine and rank the levels of criticality of transportation facilities and assess the vulnerability of the whole railway network