Alain Quilliot

• Institut Supérieur d’Informatique, de Modélisation et de leurs Applications

We deal here with a general 2-commodity flow model over a time expanded network designed for the management of a shared mobility systems. The model involves an integral flow vector that represents carriers together with an integral flow vector that represents the items transported by those carriers. It simultaneously copes with temporal and resourc...

Renewable energies currently appear to be an obvious and efficient solution to combat climate change. Among these, hydrogen possesses all the attributes to be the most renewable, clean, efficient and non-toxic form of energy. In this work, we focus on the numerical handling of the synchronization of the consumption of hydrogen by a vehicle performi...

We introduce a variant of the cumulative scheduling problem (CuSP) characterized by continuous modes, time windows, and a criterion that involves safety margin maximization. The study of this variant is motivated by the Geospatial based Environment for Optimisation Systems Addressing Fire Emergencies Horizon 2020 Project, which is devoted to the de...

This archive is distributed in association with the INFORMS Journal on Computing under the MIT License. This is a code repo for experiments in the paper "The continuous time-resource tradeoff scheduling problem with time windows" by Christian Artigues, Emmanuel Hébrard, Alain Quilliot, annd Hélène Toussaint.

Time Expanded Networks, built by considering the vertices of a base network all over some time space, are powerful tools for the formulation of problems that simultaneously involve resource assignment and scheduling. Still, in most cases, deriving algorithms from those formulations is difficult. We implement here a generic Project and Lift decompos...

Intelligent vehicles, provided with an ability to move with some level of autonomy, recently became a hot spot in the mobility field. Still, determining what can be exactly done with new generations of autonomous or semi-autonomous vehicles able to follow their way without being physically tied to any kind of track (cable, rail,\(\ldots \)) remains...

Time Expanded Networks are useful tools to model many Vehicle Routing Problems with synchronizations or resource transfers. However, such models are usually difficult to handle due to their large size and because the reduction techniques to discard some arcs and vertices may introduce errors with an unpredictable impact on feasibility and on soluti...

Abstract Time Expanded Networks, built by considering the vertices of a base network over some time space, are powerful tools for the formulation of problems that simultaneously involve resource assignment and scheduling. Still, in most cases, deriving algorithms from those formulations is difficult, due to both the size of the resulting models an...

In this paper, we deal with the Pickup and Delivery Problem with Transfers, and focus on the way a new request can be inserted into a current solution. This problem may be viewed as the search for a specific collection of constraints related to the nodes of a Time Expanded Network. It has most often been addressed in a very empirical way, and our g...

We deal here with a general 2-commodity flow model designed for the management of shared mobility systems which operate on a given transit network. The model involves an integral flow which represents carriers together with an integral flow which represents the objects transported by those carriers. It may be viewed as the projection on the transit...

Advanced intersection control systems have been created to alleviate traffic congestion. CAVs may benefit from cooperative navigation in order to address the regular traffic issue. Due to whole uncertainty in transportation network, the conventional motion planning for local areas may lead to undesirable effects in long run. In prior works, a micro...

We deal here with a fleet of autonomous vehicles which is required to perform internal logistics tasks inside some protected area. This fleet is supposed to be ruled by a hierarchical supervision architecture, which, at the top level distributes and schedules Pick up and Delivery tasks, and, at the lowest level, ensures safety at the crossroads and...

We address in this paper two problems on mirror graphs. The first is the recognition problem. While it is graph isomorphism complete, we show the analogous problem of recognizing mirror trees is solvable in linear time. The second problem we are tackling in this study is the linear ordering problem on mirror trees with respect to Directed Sum-Cut c...

Max–max, max–min, min–max and min–min optimization problems with a knapsack-type constraint containing a single numerical parameter are studied. The goal is to present optimal solutions for all possible values of the parameter. Algorithms with O(nlogn)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \use...

Synchronization of heterogeneous processes is a difficult issue in Scheduling area. Related Mathematical Programming models are difficult to handle, because of the large gaps induced by rational relaxation. We consider here renewable energy production and consumption processes, which have to be performed in situ, and so which must be managed in a s...

Delivery of goods into urban areas constitutes an important issue for logistics service providers. One of the most talked-about developments in recent years has been the potential use of unmanned aerial vehicles, or drones, for transporting packages, food, medicine, and other goods. Delivery by drones offers new possibilities, but also induces new...

In this paper we introduce a new class of Pickup and Delivery problems on circles (or rings). These problems arise in the field of public transportation systems where autonomous (i.e. driverless) vehicles travel on circular networks. We consider a set of stations arranged in a circle and a set of transportation requests. Each request asks for the t...

Synchronizing heterogeneous processes remains a difficult issue in Scheduling area. Related ILP models are in trouble, because of large gaps induced by rational relaxation. We choose here to deal with it while emulating the interactions which take place between the various players of such heterogeneous processes, and propose a pipe-line decompositi...

The emergence of locally produced renewable energies induces the appearance of a new generation of local energy players, which are at the same time producers and consumers. In case of time dependent solar energy production, it raises the question of synchronizing production and consumption. We deal here with this issue, in the context of an experim...

A problem of scheduling n unit-time jobs with a small number of distinct release dates and deadlines, on identical parallel machines, to minimize the number of active machines is studied. The feature that makes this problem challenging is that no machine can stand idle between its start and completion times. A number of properties of this problem i...

Managing a one-way vehicle sharing system means periodically using carriers (trucks, drivers, self-platoon convoys…) in order to move free access vehicles from excess to deficit stations in order to avoid local shortages. Most authors deal with a preemptive version of this problem while considering carrier routes as the master object and focusing o...

In this paper, we introduce the Steiner Bi-objective Shortest Path Problem. This problem is defined on a directed graph = (V,A) , with a subset T ⊂ V of terminals. Arcs are labeled with travel time and cost. The goal is to find a complete set of efficient paths between every pair of nodes in T. The motivation behind this problem stems from data pre...

Most time-dependent vehicle routing problems are based on a similar modeling paradigm: travel time information is represented by travel time functions between pairs of points of interest (e.g., depot or customers). Only a few papers investigate how these functions can be computed using the available travel time information. Furthermore, most of the...

The emergence of hydrogen energy produced through phoytolysis makes appear a new generation of local energy players, which are at the same time producers and consumers. This raises the question of synchronizing hydrogen production, which deeply depends on the times, and its consumption through some transportation activity.We deal here with this iss...

Braverman et al. [Math. Oper. Res. 41(1), (2016), pp. 352–376], introduce the problem Provision-after-Wait which is to find a stable (envy free) assignment of n patients to m hospitals, and their waiting times before admission, such that the social welfare is maximized, subject to a limited budget. Chan et al. [ACM Trans. Econ. Comput. 5(2), (2017)...

We study a bi-criteria path problem on a directed multigraph with cycles, where each arc is associated with two parameters. The first is the survival probability of moving along the arc, and the second is the length of the arc. We evaluate the quality of a path by two independent criteria. The first is to maximize the survival probability along the...

VIPAFLEET is a framework to manage a fleet of Individual public autonomous vehicles (VIPA). We consider a fleet of cars distributed at specified stations in an industrial area to supply internal transportation, where the cars can be used in different modes of circulation (tram mode, elevator mode, taxi mode). We treat in this paper the pickup and d...

In this paper we propose a multigraph model and a heuristic for the Vehicle Routing Problem with Time Windows (VRPTW). In the classical VRPTW, travel information is commonly represented with a customer-based graph, where an arc is an abstraction of the best road-network path between two nodes. We consider the case when parallel arcs are added to th...

The resource-constrained project scheduling problem (RCPSP), one of the most challenging combinatorial optimization scheduling problems, has been the focus of a great deal of research, resulting in numerous publications in the last decade. Previous publications focused on the RCPSP, including several extensions with different objectives to be minim...

Vehicle routing problems (VRP) concern the pickup and/or the delivery of goods from/to customers with vehicles. In the literature, most approaches consider the road network implicitly. Specifically, so‐called customer‐based graphs are used where nodes represent customers (plus the depot) and arcs represent best paths between customers. This model c...

A recent evolution in urban logistics involves the usage of drones. In this article, we address a heuristic solution of the parallel drone scheduling traveling salesman problem, recently introduced by Murray and Chu. In this problem, deliveries are split between a vehicle and drones. The vehicle performs a classical delivery tour, while the drones...

The Job-Shop scheduling Problem with Transport (JSPT) is a combinatorial optimization problem that combines both scheduling and routing problems. It has received attention for decades, resulting in numerous publications focused on the makespan minimization. The JSPT is commonly modeled by a disjunctive graph that encompasses both machine-operations...

In this paper, we consider the online uniform machine scheduling problem on m processors when speed si=1 for i=k+1,…,m and si=s, s>1, for i=1,…,k. The objective is to minimize makespan. We propose a parametric scheme with the worst-case performance 2.618 when 1<s≤2, and with the asymptotic worst-case performance [Formula presented](1+s+5−2s+s²) for...

In this article, we address the preemptive Resource-Constrained Precedence Scheduling Problem. We propose two mixed integer formulations containing an exponential number of variables and inequalities. An antichain is a set of pairwise incomparable elements with respect to the precedence constraints. In the first formulation, the integer variables a...

We study new decision and optimization problems of finding a simple path between two given vertices in an arc weighted directed multigraph such that the path length is equal to a given number or it does not fall into the given forbidden intervals (gaps). A fairly complete computational complexity classification is provided and exact and approximati...

In this paper, we consider the homogeneous m-machine scheduling problem where unit-time jobs have to be scheduled within their time windows so that, for any subset of machines, the set of the time units at which at least one machine is busy, is an interval. For this problem, a time assignment of the jobs satisfying the time windows constraints is a...

Vehicle routing problems have drawn researchers’ attention for more than 50 years. Most approaches found in the literature address these problems using the so-called customer-based graph, a complete graph representing the road network, where a node is introduced for every point of interest (eg, customers, depot…) and an arc represents the best path...

This paper deals with an extension of the integrated production and transportation scheduling problem (PTSP) by considering multiple vehicles (PTSPm) for optimisation of supply chains. The problem reflects a real concern for industry since production and transportation subproblems are commonly addressed independently or sequentially, which leads to...

The VIPAFLEET project aims at developing a framework to manage a fleet of Individual Public Autonomous Vehicles (VIPA). We consider a fleet of such cars distributed at specified stations in an industrial area to supply internal transportation, where the cars can be used in different modes of circulation (tram mode, elevator mode, taxi mode). We tre...

In this study, the definition of a RCPSPR (Resource-Constrained Project Scheduling Problem with Routing) solution from a flow solution of the RCPSP is investigated. This new problem consists in defining a solution of RCPSPR that considers both routing and scheduling and that complies with a RCPSP flow, i.e., a solution where the loaded vehicle move...

ABSTRACT Managing a one-way vehicle sharing system means periodically moving free access vehicles from excess to deficit stations in order to avoid local shortages. We propose and study here several network flow oriented models and algorithms which deal with a static version of this problem while unifying preemption and non preemption as well as ca...

This paper is devoted to study the multi-destination bi-objective shortest path problem. This problem consists in finding the set of Pareto-optimal paths linking a set of points of interest in a network. Our motivation stems from the data preprocessing for vehicle routing problems on road networks. We propose a solution method based on a labeling a...

Vehicle routing problems have drawn researchers’ attention for more than fifty years. Most approaches found in the literature are based on the key assumption that for each pair of points of interest (e.g., customers, depot...), the best origin-destination path can be computed. Thus, the problem can be addressed via a simple graph representation, wh...

The VIPAFLEET project consists in developing models and algorithms for man- aging a fleet of Individual Public Autonomous Vehicles (VIPA). Hereby, we consider a fleet of cars distributed at specified stations in an industrial area to supply internal transportation, where the cars can be used in different modes of circulation (tram mode, elevator mo...

The VIPAFLEET project consists in developing models and algorithms for man- aging a fleet of Individual Public Autonomous Vehicles (VIPA). Hereby, we consider a fleet of cars distributed at specified stations in an industrial area to supply internal transportation, where the cars can be used in different modes of circulation (tram mode, elevator mo...

We deal here with the Linear Arrangement Problem (LAP) on interval graphs, any interval graph being given here together with its representation as the intersection graph of some collection of intervals, and so with related precedence and inclusion relations. We first propose a lower bound LB , which happens to be tight in the case of unit interval...

In a combinatorial optimization problem under uncertainty, it is never the case that the real instance is exactly the baseline instance that has been solved earlier. The anchorage level is the number of individual decisions with the same value in the solutions of the baseline and the real instances. We consider the case of CPM-scheduling with simpl...

We study a 0-1 knapsack problem, in which the objective value is forbidden to take some values. We call gaps related forbidden intervals. The problem is NP-hard and pseudo-polynomially solvable independently on the measure of gaps. If the gaps are large, then the problem is polynomially non-approximable. A non-trivial special case with respect to t...

For many years companies and researchers addressed the production and transportation sub-problems separately and sequentially. The problem considered in this paper is the integrated production and transportation scheduling problem (PTSP) with capacity constraints and a short shelf life product with several vehicles. This problem encompasses as spec...

The VIPAFLEET project consists in developing models and algorithms for man- aging a fleet of Individual Public Autonomous Vehicles (VIPA). Hereby, we consider a fleet of cars distributed at specified stations in an industrial area to supply internal transportation, where the cars can be used in different modes of circulation (tram mode, elevator mo...

Health organizations are complex to manage due to their dynamic processes and distributed hospital organization. It is therefore necessary for healthcare institutions to focus on this issue to deal with patients' requirements. We aim in this paper to develop and implement a management decision support system (DSS) that can help physicians to better...

We consider a static decision model related to the management of a Dial-a-Ride (DAR) system involving small autonomous electrical vehicles in a closed industrial site. Because of the specific features of the system, in this paper we concentrate on its reliability and propose a model that aims at assigning requests to vehicles by minimizing the numb...

Emergency health care services have a highly complex patient treatment system. This system is characterized by stochastic arrivals of patients which can lead in the case of activity to its services overload. In fact, the complexity of these medical exercises relays on assigning health care operations to medical staff members respecting constraints...

This paper first describes an efficient exact algorithm to solve Preemptive RCPSP and next discusses its extension to Non Preemptive RCPSP. In case of Pre- emptive RCPSP, we propose a very original and efficient branch and bound/price procedure based upon minimal interval order enumeration, which is implemented with the help of the generic SCIP sof...

In a carsharing system, a fleet of cars is distributed at stations in an urban area, customers can take and return cars at any time and station. For operating such a system in a satisfactory way, the stations have to keep a good ratio between the total number of places and cars in each station, in order to refuse as few customer requests as possibl...

In a carsharing system, a fleet of cars is distributed at stations in an urban area, customers can take and return cars at any time and station. For operating such a system in a satisfactory way, the stations have to keep a good ratio between the numbers of free places and cars in each station. This leads to the problem of relocating cars between s...

In a carsharing system, a fleet of cars is distributed at stations in an urban area, customers can take and return cars at any time and station. For operating such a system in a satisfactory way, the stations have to keep a good ratio between the numbers of free places and cars in each station. This leads to the problem of relocating cars between s...