2,528 research outputs found
Modelling and controlling traffic behaviour with continuous Petri nets
Traffic systems are discrete systems that can be heavily populated. One way of overcoming the state explosion problem inherent to heavily populated discrete systems is to relax the discrete model. Continuous Petri nets (PN) represent a relaxation of the original discrete Petri nets that leads to a compositional formalism to model traffic behaviour. This paper introduces some new features of continuous Petri nets that are useful to obtain realistic but compact models for traffic systems. Combining these continuous PN models with discrete PN models of traffic lights leads to a hybrid Petri net model that is appropriate for predicting traffic behaviour, and for designing trac light controllers that minimize the total delay of the vehicles in the system
ZASTOSOWANIE SIECI PETRIEGO W SYSTEMACH WSPOMAGANIA DECYZJI OPARTYCH NA INTELIGENTNEJ WIELOŹRÓDŁOWEJ ANALIZIE DANYCH
The paper deals with the design of data analysis systems for business process automation. A general scheme of decision support system was developed in which one of the modules is based on Petri Nets. The way of implementation of Petri Net model in optimization problem regarding service-oriented decision support system was shown. The Petri Net model of distribution workflow was presented and simulation experiments was completed. As a result the optimal solution as a set of parameters was emerged.Artykuł dotyczy problematyki projektowania zautomatyzowanych systemów analizy danych biznesowych. Opracowano ogólny model systemu wspomagania decyzji, w którym jeden z modułów funkcjonuje w oparciu o sieci Petriego. Zaprezentowano sposób implementacji sieci Petriego do realizacji zadań optymalizacyjnych dotyczących zorientowanego na usługi systemu wspomagania decyzji. Przeprowadzono szereg eksperymentów symulacyjnych wykorzystując model przepływu pracy utworzony na bazie sieci Petriego. Rezultatem badań było wyłonienie optymalnego zbioru parametrów procesu biznesowego
Intersection Collision Avoidance For Autonomous Vehicles Using Petri Nets
Indiana University-Purdue University Indianapolis (IUPUI)Autonomous vehicles currently dominate the automobile field for their impact on
humanity and society. Connected and Automated Vehicles (CAV’s) are vehicles that
use different communication technologies to communicate with other vehicles, infrastructure, the cloud, etc. With the information received from the sensors present, the
vehicles analyze and take necessary steps for smooth, collision-free driving. This
the
sis talks about the cruise control system along with the intersection collision avoidance
system based on Petri net models. It consists of two internal controllers for velocity
and distance control, respectively, and three external ones for collision avoidance.
Fault-tolerant redundant controllers are designed to keep these three controllers in
check. The model is built using a PN toolbox and tested for various scenarios. The
model is also validated, and its distinct properties are analyzed
Reliability modelling of PEM fuel cells with hybrid Petri nets
In this paper, a novel model for dynamic reliability analysis of a PEM fuel cell system is developed using Modelica language in order to account for multi-state dynamics and aging. The modelling approach constitutes the combination of physical and stochastic sub-models with shared variables. The physical model consist of deterministic calculations of the system state described by variables such as temperature, pressure, mass flow rates and voltage output. Additionally, estimated component degradation rates are also taken into account.
The non-deterministic model, on the other hand, is implemented with stochastic Petri nets which represent different events that can occur at random times during fuel cell lifetime. A case study of effects of a cooling system on fuel cell performance was investigated. Monte Carlo simulations of the process resulted in a distribution of system parameters, thus providing an estimate of best and worst scenarios of a fuel cell lifetime
Petri Nets Models for Analysis and Control of Public Bicycle-Sharing Systems
International audienc
Hybrid Petri nets-based Flow modeling and application on hybrid system.
Flow management is necessary in several application areas, in the optimization of industrial production lines, in IT to manage data flows and in the automation of industrial systems. Physical systems in general consist of continuous processes interacting with discrete processes forming a hybrid dynamic system constituted by continuous dynamic type models and discrete events. The application of the hybrid Petri nets tool in the modeling, study and performance evaluation of these systems helps to analyze the dynamic properties by acting on the parameters and the structure of the models in order to evaluate their behavior. This work is focused on the application of this tool to model a material flow management system between a rotary kiln and a clinker cooler in a production line (cement process). The implementation of the modeling and the analysis of the results obtained by simulation on a software platform (Visual Object Net ++), aims to study industrial processes with mathematical tools and to follow their behavior on software, this allows us an optimal analysis of complex systems in dangerous environments, and to try practical and effective solutions by simple means before moving on to the implementation and programming of actions that require more expensive means
Abridged Petri Nets
A new graphical framework, Abridged Petri Nets (APNs) is introduced for
bottom-up modeling of complex stochastic systems. APNs are similar to
Stochastic Petri Nets (SPNs) in as much as they both rely on component-based
representation of system state space, in contrast to Markov chains that
explicitly model the states of an entire system. In both frameworks, so-called
tokens (denoted as small circles) represent individual entities comprising the
system; however, SPN graphs contain two distinct types of nodes (called places
and transitions) with transitions serving the purpose of routing tokens among
places. As a result, a pair of place nodes in SPNs can be linked to each other
only via a transient stop, a transition node. In contrast, APN graphs link
place nodes directly by arcs (transitions), similar to state space diagrams for
Markov chains, and separate transition nodes are not needed.
Tokens in APN are distinct and have labels that can assume both discrete
values ("colors") and continuous values ("ages"), both of which can change
during simulation. Component interactions are modeled in APNs using triggers,
which are either inhibitors or enablers (the inhibitors' opposites).
Hierarchical construction of APNs rely on using stacks (layers) of submodels
with automatically matching color policies. As a result, APNs provide at least
the same modeling power as SPNs, but, as demonstrated by means of several
examples, the resulting models are often more compact and transparent,
therefore facilitating more efficient performance evaluation of complex
systems.Comment: 17 figure
Distributed control of urban traffic networks using hybrid models
Urban traffic control poses a challenging problem in terms of coordinating the different traffic lights that can be used in order to influence the traffic flow. Model based control requires hybrid systems models consisting of interacting fluid flow Petri net models for controlled and uncontrolled intersections, and cell transmission models for links connecting the intersections. This paper proposes a simulation based distributed model predictive control algorithm for solving this problem
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