Karim Labadi - Academia.edu (original) (raw)

Papers by Karim Labadi

Research paper thumbnail of A branch and bound algorithm for solving the static rebalancing problem in bicycle-sharing systems (Working paper)

Research paper thumbnail of Metaheuristic methods for solving the static balancing problem in bicycle sharing systems

Research paper thumbnail of Modeling and Performance Evaluation of Inventory Systems Using Batch Deterministic and Stochastic Petri Nets

Research paper thumbnail of SUR LA REGULATION DES SYSTEMES DE VELOS EN LIBRE-SERVICE APPROCHE BASEE SUR LES RESEAUX DE PETRI AVEC DES ARCS A POIDS …

RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dan... more RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dans plusieurs villes en Europe (Vélib' à Paris, Vélov'v à Lyon, Bicing à Barcelone, etc.). Contrairement aux systèmes de transport traditionnels, très peu d'études fondamentales (voire aucune) ont été menées. Pourtant, de nombreuses questions émergent, la principale étant la question d'une régulation efficace. Le travail développé dans cet article est d'une aide précieuse pour la mise en oeuvre et l'exploitation des systèmes de vélos en libre-service. Nous développons un modèle dynamique pouvant prendre en compte toute la dimension du fonctionnement de ce type de systèmes. Notre approche repose sur les réseaux de Petri (avec des poids sur les arcs variables en fonction du marquage actuel) pertinents aussi bien pour l'analyse que pour la simulation. A notre connaissance, il s'agit d'un premier travail du genre dans la littérature sur les réseaux de Petri et plus généralement sur la régulation des systèmes de vélos en libre-service. MOTS-CLES : systèmes de vélos en libre-service, régulation, réseaux de Petri.

Research paper thumbnail of BATCH DETERMINISTIC AND STOCHASTIC PETRI NETS: MODELLING, ANALYSIS AND APPLICATION TO INVENTORY SYSTEMS

We recently introduced a new stochastic Petri net model called "batch deterministic and stoc... more We recently introduced a new stochastic Petri net model called "batch deterministic and stochastic Petri nets" (BDSPNs) capable of describing the synchronization of discrete and batch token flows in discrete batch processes. It is a powerful formal model for the study of inventory systems and supply chains where materials are processed or ordered in finite discrete quantities (batches) and many

Research paper thumbnail of Batch deterministic and stochastic Petri nets modeling, analysis and its application to supply chain

2004 IEEE International Conference on Systems, Man and Cybernetics (IEEE Cat. No.04CH37583), 2004

Research paper thumbnail of Balancing dynamic bike-sharing systems: A Petri nets with variable arc weights based approach

2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013

ABSTRACT

Research paper thumbnail of Real-time inventory control and rebalancing in bike-sharing systems by using a stochastic Petri net model

3rd International Conference on Systems and Control, 2013

ABSTRACT Bike sharing systems are becoming an urban mode of transportation that currently spreadi... more ABSTRACT Bike sharing systems are becoming an urban mode of transportation that currently spreading in developed countries. The exploitation of such systems implies numerous operational challenges and one of them is to ensure people that they will be able to find a bike or to park it at each station. Therefore, the regulation system is necessary for maintaining a prefixed number of bikes at each station in order to fulfill at best the demand. In this paper, we develop a new stochastic Petri net model for control and performance evaluation of such transportation systems. Compared to our published works, in this paper, we consider a new rebalancing policy based on a real-time alert system with three levels of the stations control namely Ei (engorgement alert level), Pi (penury alert level) and Ri (desired level point).

Research paper thumbnail of A new upper bound of cycle time in weighted marked graphs

2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013

Research paper thumbnail of Sujet de stage pour Master2 Recherche (2007-2008)

Research paper thumbnail of Marking of Fluid Timed Events Graphs with Multipliers for a desired cycle time

We study fluid analogues of a subclass of petri nets, called Fluid Timed Event Graphs with Multip... more We study fluid analogues of a subclass of petri nets, called Fluid Timed Event Graphs with Multipliers, which are a time extension of weighted T-Systems studied in the Petri Net literature. These event graphs can be studied in the algebraic structure called (min, +) algebra. In this paper we deal with the problem of allocating an initial marking in a

Research paper thumbnail of Sur la régulation des systèmes de vélos en libre-service : approche basée sur les réseaux de Petri avec des arcs a poids variables

RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dan... more RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dans plusieurs villes en Europe (Vélib' à Paris, Vélov'v à Lyon, Bicing à Barcelone, etc.). Contrairement aux systèmes de transport traditionnels, très peu d'études fondamentales (voire aucune) ont été menées. Pourtant, de nombreuses questions émergent, la principale étant la question d'une régulation efficace. Le travail développé dans cet article est d'une aide précieuse pour la mise en oeuvre et l'exploitation des systèmes de vélos en libre-service. Nous développons un modèle dynamique pouvant prendre en compte toute la dimension du fonctionnement de ce type de systèmes. Notre approche repose sur les réseaux de Petri (avec des poids sur les arcs variables en fonction du marquage actuel) pertinents aussi bien pour l'analyse que pour la simulation. A notre connaissance, il s'agit d'un premier travail du genre dans la littérature sur les réseaux de Petri et plus généralement sur la régulation des systèmes de vélos en libre-service. MOTS-CLES : systèmes de vélos en libre-service, régulation, réseaux de Petri.

Research paper thumbnail of On Marking of Continuous Generalized Timed Events Graphs

Research paper thumbnail of Dimensionnement d'un système de production flexible par l’analyse de perturbations

Research paper thumbnail of Transformation Methods of the BDSPN Model into an Equivalent Classical Petri Net

EUROCON 2007 - The International Conference on "Computer as a Tool", 2007

The BDSPN model is a class of Petri nets introduced for the modeling, analysis and performance ev... more The BDSPN model is a class of Petri nets introduced for the modeling, analysis and performance evaluation of discrete event systems with batch behaviors. The model is particularly suitable for the modeling of flow evolution in discrete quantities (batches of variable sizes) in a system with activities performed in batch modes. The work of this paper contributes to the structural

Research paper thumbnail of The Just-in-Time control of Timed Event Graphs with Multipliers in dioids

EUROCON 2007 - The International Conference on "Computer as a Tool", 2007

Timed event graphs with multipliers, also called timed weighted marked graphs, constitute a subcl... more Timed event graphs with multipliers, also called timed weighted marked graphs, constitute a subclass of Petri nets well adapted to model discrete event systems involving synchronization and saturation phenomena. Their dynamic behaviors can be modeled by using a particular algebra, called dioid, defined on a set of operators and endowed with the pointwise minimum operation as addition and the composition

Research paper thumbnail of Stochastic Petri Net Modeling, Simulation and Analysis of Public Bicycle Sharing Systems

IEEE Transactions on Automation Science and Engineering, 2014

ABSTRACT

Research paper thumbnail of Perturbation Analysis to set the number of automated guided vehicles in a flexible manufacturing system

The Fourth International Conference on Control and Automation 2003 ICCA Final Program and Book of Abstracts ICCA-03, 2003

By using perturbation analysis on a simulation model of a flexible manufacturing system, this pap... more By using perturbation analysis on a simulation model of a flexible manufacturing system, this paper proposes a procedure to size this system in order to maximize its productivity. This procedure is based on the identification of the function between flowtime (i.e., the flowtime for each product is computed as the delay between its completion time and its arrival time) and

Research paper thumbnail of Parameter Perturbation Analysis through Stochastic Petri Nets: Application to an Inventory System

Advances in Petri Net Theory and Applications, 2010

ABSTRACT The theoretical results presented in this chapter are a natural extension of the recent ... more ABSTRACT The theoretical results presented in this chapter are a natural extension of the recent development on sensitivity analysis of stochastic processes. The main idea is to obtain the derivates of a performance measure of a discrete event dynamic system based on its stochastic Petri model. In this work, the SPN model is studied. A Parameter Sensitivity analysis approach for the model is developed and an application to a supply chain is studied. We note that the proposed methodology is also applicable to GSPN (Generalized Stochastic Petri Nets) models since the marking process of a bounded GSPN is also a Markov process. The development of sensitivity analysis methods for non Markovian

Research paper thumbnail of Performance Evaluation of Timed Petri Nets in Dioid Algebra

Petri Nets - Manufacturing and Computer Science, 2012

Research paper thumbnail of A branch and bound algorithm for solving the static rebalancing problem in bicycle-sharing systems (Working paper)

Research paper thumbnail of Metaheuristic methods for solving the static balancing problem in bicycle sharing systems

Research paper thumbnail of Modeling and Performance Evaluation of Inventory Systems Using Batch Deterministic and Stochastic Petri Nets

Research paper thumbnail of SUR LA REGULATION DES SYSTEMES DE VELOS EN LIBRE-SERVICE APPROCHE BASEE SUR LES RESEAUX DE PETRI AVEC DES ARCS A POIDS …

RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dan... more RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dans plusieurs villes en Europe (Vélib' à Paris, Vélov'v à Lyon, Bicing à Barcelone, etc.). Contrairement aux systèmes de transport traditionnels, très peu d'études fondamentales (voire aucune) ont été menées. Pourtant, de nombreuses questions émergent, la principale étant la question d'une régulation efficace. Le travail développé dans cet article est d'une aide précieuse pour la mise en oeuvre et l'exploitation des systèmes de vélos en libre-service. Nous développons un modèle dynamique pouvant prendre en compte toute la dimension du fonctionnement de ce type de systèmes. Notre approche repose sur les réseaux de Petri (avec des poids sur les arcs variables en fonction du marquage actuel) pertinents aussi bien pour l'analyse que pour la simulation. A notre connaissance, il s'agit d'un premier travail du genre dans la littérature sur les réseaux de Petri et plus généralement sur la régulation des systèmes de vélos en libre-service. MOTS-CLES : systèmes de vélos en libre-service, régulation, réseaux de Petri.

Research paper thumbnail of BATCH DETERMINISTIC AND STOCHASTIC PETRI NETS: MODELLING, ANALYSIS AND APPLICATION TO INVENTORY SYSTEMS

We recently introduced a new stochastic Petri net model called "batch deterministic and stoc... more We recently introduced a new stochastic Petri net model called "batch deterministic and stochastic Petri nets" (BDSPNs) capable of describing the synchronization of discrete and batch token flows in discrete batch processes. It is a powerful formal model for the study of inventory systems and supply chains where materials are processed or ordered in finite discrete quantities (batches) and many

Research paper thumbnail of Batch deterministic and stochastic Petri nets modeling, analysis and its application to supply chain

2004 IEEE International Conference on Systems, Man and Cybernetics (IEEE Cat. No.04CH37583), 2004

Research paper thumbnail of Balancing dynamic bike-sharing systems: A Petri nets with variable arc weights based approach

2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013

ABSTRACT

Research paper thumbnail of Real-time inventory control and rebalancing in bike-sharing systems by using a stochastic Petri net model

3rd International Conference on Systems and Control, 2013

ABSTRACT Bike sharing systems are becoming an urban mode of transportation that currently spreadi... more ABSTRACT Bike sharing systems are becoming an urban mode of transportation that currently spreading in developed countries. The exploitation of such systems implies numerous operational challenges and one of them is to ensure people that they will be able to find a bike or to park it at each station. Therefore, the regulation system is necessary for maintaining a prefixed number of bikes at each station in order to fulfill at best the demand. In this paper, we develop a new stochastic Petri net model for control and performance evaluation of such transportation systems. Compared to our published works, in this paper, we consider a new rebalancing policy based on a real-time alert system with three levels of the stations control namely Ei (engorgement alert level), Pi (penury alert level) and Ri (desired level point).

Research paper thumbnail of A new upper bound of cycle time in weighted marked graphs

2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013

Research paper thumbnail of Sujet de stage pour Master2 Recherche (2007-2008)

Research paper thumbnail of Marking of Fluid Timed Events Graphs with Multipliers for a desired cycle time

We study fluid analogues of a subclass of petri nets, called Fluid Timed Event Graphs with Multip... more We study fluid analogues of a subclass of petri nets, called Fluid Timed Event Graphs with Multipliers, which are a time extension of weighted T-Systems studied in the Petri Net literature. These event graphs can be studied in the algebraic structure called (min, +) algebra. In this paper we deal with the problem of allocating an initial marking in a

Research paper thumbnail of Sur la régulation des systèmes de vélos en libre-service : approche basée sur les réseaux de Petri avec des arcs a poids variables

RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dan... more RESUME : Au cours de ces dernières années, des systèmes de vélos en libre-service fleurissent dans plusieurs villes en Europe (Vélib' à Paris, Vélov'v à Lyon, Bicing à Barcelone, etc.). Contrairement aux systèmes de transport traditionnels, très peu d'études fondamentales (voire aucune) ont été menées. Pourtant, de nombreuses questions émergent, la principale étant la question d'une régulation efficace. Le travail développé dans cet article est d'une aide précieuse pour la mise en oeuvre et l'exploitation des systèmes de vélos en libre-service. Nous développons un modèle dynamique pouvant prendre en compte toute la dimension du fonctionnement de ce type de systèmes. Notre approche repose sur les réseaux de Petri (avec des poids sur les arcs variables en fonction du marquage actuel) pertinents aussi bien pour l'analyse que pour la simulation. A notre connaissance, il s'agit d'un premier travail du genre dans la littérature sur les réseaux de Petri et plus généralement sur la régulation des systèmes de vélos en libre-service. MOTS-CLES : systèmes de vélos en libre-service, régulation, réseaux de Petri.

Research paper thumbnail of On Marking of Continuous Generalized Timed Events Graphs

Research paper thumbnail of Dimensionnement d'un système de production flexible par l’analyse de perturbations

Research paper thumbnail of Transformation Methods of the BDSPN Model into an Equivalent Classical Petri Net

EUROCON 2007 - The International Conference on "Computer as a Tool", 2007

The BDSPN model is a class of Petri nets introduced for the modeling, analysis and performance ev... more The BDSPN model is a class of Petri nets introduced for the modeling, analysis and performance evaluation of discrete event systems with batch behaviors. The model is particularly suitable for the modeling of flow evolution in discrete quantities (batches of variable sizes) in a system with activities performed in batch modes. The work of this paper contributes to the structural

Research paper thumbnail of The Just-in-Time control of Timed Event Graphs with Multipliers in dioids

EUROCON 2007 - The International Conference on "Computer as a Tool", 2007

Timed event graphs with multipliers, also called timed weighted marked graphs, constitute a subcl... more Timed event graphs with multipliers, also called timed weighted marked graphs, constitute a subclass of Petri nets well adapted to model discrete event systems involving synchronization and saturation phenomena. Their dynamic behaviors can be modeled by using a particular algebra, called dioid, defined on a set of operators and endowed with the pointwise minimum operation as addition and the composition

Research paper thumbnail of Stochastic Petri Net Modeling, Simulation and Analysis of Public Bicycle Sharing Systems

IEEE Transactions on Automation Science and Engineering, 2014

ABSTRACT

Research paper thumbnail of Perturbation Analysis to set the number of automated guided vehicles in a flexible manufacturing system

The Fourth International Conference on Control and Automation 2003 ICCA Final Program and Book of Abstracts ICCA-03, 2003

By using perturbation analysis on a simulation model of a flexible manufacturing system, this pap... more By using perturbation analysis on a simulation model of a flexible manufacturing system, this paper proposes a procedure to size this system in order to maximize its productivity. This procedure is based on the identification of the function between flowtime (i.e., the flowtime for each product is computed as the delay between its completion time and its arrival time) and

Research paper thumbnail of Parameter Perturbation Analysis through Stochastic Petri Nets: Application to an Inventory System

Advances in Petri Net Theory and Applications, 2010

ABSTRACT The theoretical results presented in this chapter are a natural extension of the recent ... more ABSTRACT The theoretical results presented in this chapter are a natural extension of the recent development on sensitivity analysis of stochastic processes. The main idea is to obtain the derivates of a performance measure of a discrete event dynamic system based on its stochastic Petri model. In this work, the SPN model is studied. A Parameter Sensitivity analysis approach for the model is developed and an application to a supply chain is studied. We note that the proposed methodology is also applicable to GSPN (Generalized Stochastic Petri Nets) models since the marking process of a bounded GSPN is also a Markov process. The development of sensitivity analysis methods for non Markovian

Research paper thumbnail of Performance Evaluation of Timed Petri Nets in Dioid Algebra

Petri Nets - Manufacturing and Computer Science, 2012