Modeling the Permeable Power of the Road on a Semaforized Crossing Using Petri Nets

With the growth in demand and the development of traffic over the last fifty years, the need for the introduction of Intelligent Transport Systems (ITS) is growing every day. With a modern approach they solve complex traffic problems. One modern approach is modeling the dynamics of Petri Nets. The Petri Nets is a powerful graphical and mathematical model for working with discrete systems. This paper describes how using a Petri Net can manage signaled intersections, assist in choosing the best alternative route, or manage an intersection at which an incident occurred. The research was carried out in a real traffic environment, at the intersection of Zagrebačka Road and Bistrička Road in the center of the city Sesvete, by modeling with coloured timed Petri Nets

Combining SysML and Timed Coloured Petri Nets for Designing Smart City Applications

A smart city is an urban centre that integrates a variety of solutions to improve infrastructure performance and achieve sustainable urban development. Urban roads are a crucial infrastructure highly demanded by citizens and organisations interested in their deployment, performance, and safety. Urban traffic signal control is an important and challenging real-world problem that aims to monitor and improve traffic congestion. The deployment of traffic signals for vehicles or pedestrians at an intersection is a complex activity that changes constantly, so it is necessary to establish rules to control the flow of vehicles and pedestrians. Thus, this article describes the joint use of the SmartCitySysML, a profile proposed by the authors, with TCPN (Timed Coloured Petri Nets) to refine and formally model SysML diagrams specifying the internal behaviour, and then verify the developed model to prove behavioural properties of an urban traffic signal control system

A SysML profile for smart city applications

A smart city is an urban center that integrates a variety of solutions to enhance infrastructure performance and achieve sustainable urban development. Urban roads are a critical infrastructure highly demanded by citizens and organizations interested in their deployment, performance, and safety. Urban traffic signal control is a major and challenging problem in the real world, which aims to monitor and enhance traffic congestion. Therefore, the deployment of traffic signals for vehicles or pedestrians at a junction is a complex activity, as it is necessary to establish rules to control the flow of vehicles and pedestrians. Also, traffic flow at intersections changes constantly, depending on weather conditions, day of the week, and period of the year, as well as road works and accidents that further influence complexity and performance. This thesis first describes SmartCitySysML, a proposed profile that adapts SysML with special elements that are specific to smart cities. In addition, an extension of the SmartCitySysML profile to the design of the dimensions of smart cities is proposed. Finally, integration of models is performed, that is, the integration of the SmartCitySysML profile with Petri Net to separately model the basic architectural elements (sensor, controller, and actuator) of an urban traffic control system as sub-models to describe the behavior of each element, and the integration of the SmartCitySysML profile with Timed Coloured Petri Nets (TCPN) for modeling, simulation, and verification of properties of an urban traffic signal control system. CPN tools allow the evaluation of the model behavior through simulation and property verification and perform a simulation-based performance. Model simulation allows observing the behavior of the system under conditions that would be difficult to organize in a truly controlled environment. Consequently, a preliminary evaluation can be performed in the early stages of system development, significantly reducing costs of improvements and increasing quality of the final product.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESUma cidade inteligente é um centro urbano que integra uma variedade de soluções para melhorar o desempenho da infraestrutura e alcançar um desenvolvimento urbano sustentável. As estradas urbanas são uma infraestrutura crucial altamente exigida pelos cidadãos e organizações interessadas em sua implantação, desempenho e segurança. O controle de sinais de trânsito urbano é um problema importante e desafiador no mundo real, que visa monitorar e melhorar o congestionamento de trânsito. Portanto, a implantação de semáforos para veículos ou pedestres em um cruzamento é uma atividade complexa, pois é necessário estabelecer regras para controlar o fluxo de veículos e pedestres. O fluxo de tráfego no cruzamento muda constantemente, dependendo das condições climáticas, dia da semana e período do ano, assim como obras e acidentes rodoviários que influenciam ainda mais a complexidade e o desempenho. Esta dissertação descreve primeiro o SmartCitySysML, um perfil proposto que adapta a SysML com elementos especiais que são específicos para cidades inteligentes. Depois, é elaborada uma extensão do perfil SmartCitySysML para o design das dimensões das cidades inteligentes. Em seguida, é realizada a integração de modelos, ou seja, a integração do perfil SmartCitySysML com Redes de Petri para modelar separadamente os elementos arquiteturais básicos (sensor, controlador e atuador) de um sistema de controle de tráfego urbano como sub-modelos para demonstrar o comportamento de cada elemento, e a integração do perfil SmartCitySysML com Redes de Petri Colorida Temporizada (TCPN) para modelagem, simulação e verificação de propriedades do sistema de controle de sinais de trânsito urbano. As ferramentas CPN permitem avaliar o comportamento do modelo por meio de simulação e verificação de propriedades e realizar um desempenho baseado em simulação. A simulação de modelos permite observar o comportamento do sistema sob condições que seriam difíceis de organizar em um ambiente realmente controlado. Consequentemente, uma avaliação preliminar pode ser realizada nos estágios iniciais de desenvolvimento do sistema, reduzindo significativamente os custos de melhorias e aumentando a qualidade do produto final.São Cristóvão, S

Survivability modeling for cyber-physical systems subject to data corruption

Cyber-physical critical infrastructures are created when traditional physical infrastructure is supplemented with advanced monitoring, control, computing, and communication capability. More intelligent decision support and improved efficacy, dependability, and security are expected. Quantitative models and evaluation methods are required for determining the extent to which a cyber-physical infrastructure improves on its physical predecessors. It is essential that these models reflect both cyber and physical aspects of operation and failure. In this dissertation, we propose quantitative models for dependability attributes, in particular, survivability, of cyber-physical systems. Any malfunction or security breach, whether cyber or physical, that causes the system operation to depart from specifications will affect these dependability attributes. Our focus is on data corruption, which compromises decision support -- the fundamental role played by cyber infrastructure. The first research contribution of this work is a Petri net model for information exchange in cyber-physical systems, which facilitates i) evaluation of the extent of data corruption at a given time, and ii) illuminates the service degradation caused by propagation of corrupt data through the cyber infrastructure. In the second research contribution, we propose metrics and an evaluation method for survivability, which captures the extent of functionality retained by a system after a disruptive event. We illustrate the application of our methods through case studies on smart grids, intelligent water distribution networks, and intelligent transportation systems. Data, cyber infrastructure, and intelligent control are part and parcel of nearly every critical infrastructure that underpins daily life in developed countries. Our work provides means for quantifying and predicting the service degradation caused when cyber infrastructure fails to serve its intended purpose. It can also serve as the foundation for efforts to fortify critical systems and mitigate inevitable failures --Abstract, page iii

The Application of Petri Nets in Intelligent Transportation Systems

Inteligentni transportni sustavi se sve više upotrebljabaju u prometu i transportu. Svojim modernim pristupom rješavaju kompleksne prometne probleme. Jedan od tih načina je modeliranje dinamike Petrijevim mrežama. Petrijeve mreže su moćan grafički i matematički model za rad s diskretnim sustavima. U radu je opisano kako različiti oblici Petrijevih mreža mogu upravljati signaliziranim raskrižjima, pomoći u izboru najbolje alternativne rute ili upravljati raskrižjem na kojemu se dogodio incident. Također, prikazani su softverski alati koji su lako dostupni, a s kojima se na jednostavan način grafički prikazuju Petrijeve mreže.Intelligent transport systems are increasingly used in traffic and transport. With their modern approach, they solve complex problems in traffic. One of the approaches is modelling dynamics with Petri Nets. Petri Nets are powerful graphical and mathematical tools for discrete systems. In the paper IT will be shown how different kinds of Petri Nets can control signalized intersection, help to choose the best alternative rutes or control intersection with incidents. Also, software tools that are easily available are shown and by which Petri nets are graphically displayed in a simple way

Extending natural hazard impacts: an assessment of landslide disruptions on a national road transportation network

Disruptions to transportation networks by natural hazard events cause direct losses (e.g. by physical damage) and indirect socio-economic losses via travel delays and decreased transportation efficiency. The severity and spatial distribution of these losses varies according to user travel demands and which links, nodes or infrastructure assets are physically disrupted. Increasing transport network resilience, for example by targeted mitigation strategies, requires the identification of the critical network segments which if disrupted would incur undesirable or unacceptable socio-economic impacts. Here, these impacts are assessed on a national road transportation network by coupling hazard data with a transport network model. This process is illustrated using a case study of landslide hazards on the road network of Scotland. A set of possible landslide-prone road segments is generated using landslide susceptibility data. The results indicate that at least 152 road segments are susceptible to landslides, which could cause indirect economic losses exceeding £35 k for each day of closure. In addition, previous estimates for historic landslide events might be significant underestimates. For example, the estimated losses for the 2007 A83 'Rest and Be Thankful' landslide are £80 k day−1, totalling £1.2 million over a 15 day closure, and are ~60% greater than previous estimates. The spatial distribution of impact to road users is communicated in terms of 'extended hazard impact footprints'. These footprints reveal previously unknown exposed communities and unanticipated spatial patterns of severe disruption. Beyond cost-benefit analyses for landslide mitigation efforts, the approach implemented is applicable to other natural hazards (e.g. flooding), combinations of hazards, or even other network disruption events