Multi Site Coordination using a Multi-Agent System

A new approach of coordination of decisions in a multi site system is proposed. It is based this approach on a multi-agent concept and on the principle of distributed network of enterprises. For this purpose, each enterprise is defined as autonomous and performs simultaneously at the local and global levels. The basic component of our approach is a so-called Virtual Enterprise Node (VEN), where the enterprise network is represented as a set of tiers (like in a product breakdown structure). Within the network, each partner constitutes a VEN, which is in contact with several customers and suppliers. Exchanges between the VENs ensure the autonomy of decision, and guarantiee the consistency of information and material flows. Only two complementary VEN agents are necessary: one for external interactions, the Negotiator Agent (NA) and one for the planning of internal decisions, the Planner Agent (PA). If supply problems occur in the network, two other agents are defined: the Tier Negotiator Agent (TNA) working at the tier level only and the Supply Chain Mediator Agent (SCMA) working at the level of the enterprise network. These two agents are only active when the perturbation occurs. Otherwise, the VENs process the flow of information alone. With this new approach, managing enterprise network becomes much more transparent and looks like managing a simple enterprise in the network. The use of a Multi-Agent System (MAS) allows physical distribution of the decisional system, and procures a heterarchical organization structure with a decentralized control that guaranties the autonomy of each entity and the flexibility of the network

Deliveries optimization by exploiting production traceability information

International audienceThe recent product traceability requirements, particularly in food production chains, demonstrate an industrial need to improve traceability systems. Having real-time access to traceability information allows its exploitation, which is the aim of this work. In this paper the problem of minimizing the cost of products recall is treated. First the raw material dispersion problem is analyzed, in order to determine a risk level criterion or "production criticality". This criterion is used subsequently to optimize deliveries dispatch with the purpose of minimizing the number of batch recalls in case of crisis. This is achieved by implementing decision-making aid tools based on operational research and artificial intelligence

Configuring a machining operation as a Constraint Satisfaction Problem

International audienceThe problem of configuring a machining operation is complex (many parameters and many interactions between parameters) and is generally achieved thanks to expert heuristic knowledge. Indeed, the configuration of a machining operation is often carried out according to a specific procedure: choice of a kind of operation and of a kind of machine, then choice of a set of tools and at the end selection of cutting conditions. We propose in this paper a general framework for the configuration of a machining operation based on a constraint representation and manipulation. We first present a model of the decision variables (such as the machine, the tool, the insert or the feed rate), the non-decision variable and the constraints between variables. An overview of the 32 identified constraints is given in the paper. Even though it is not exhaustive, the basic constraints of the domain are represented. A typology of the constraints to be manipulated is then given leading order to a specification of algorithms for search and consistency checking that may allow to manage these kinds of constraints

Optimisation du transport mutualisé d'enfants en situation de handicap avec véhicules reconfigurables

National audienceEn 2010, le transport sanitaire est devenu l’une des dix priorités du plan de gestion des risques de l’Assurance maladie du fait de l’augmen-tation du coût de ces transports. Pour l’établissements médico-sociaux (EMS), ce coût représentent la deuxième dépense après celle du person-nel. Dans ce contexte, ce projet de recherche vise une amélioration globale de la prise en charge du transport quotidien des enfants en structuresde service médico-sociaux. En conséquence nous proposons la mutualisation du transport entre plusieurs EMS. Cette mutualisation du transportpermet de regrouper des tournées dans une certaine zone géographique. L’enjeu est d’améliorer la performance économique tout en maintenantdes objectifs économiques, sociaux et environnementaux. D’un point de vue scientifique ce problème est nommé le Dial-a-Ride Problem (DARP).Ce problème est démontre NP-Hard. Tout d’abord nous cherchons à intégrer au DARP avec véhicules adaptées la notion de reconfigurationpendant la tournée. Pour résoudre ce problème, nous utilisons la métaheuristique Large Neighborhood Search

Gestion collaborative et distribuée des approvisionnements intégrant le transport

L'enjeu croissant du problème des transports dans la gestion des chaînes logistiques, implique que les décisions de management intègrent étroitement problèmes de production et problèmes de transport. Dans ce contexte, nous nous intéressons ici à la gestion collaborative des approvisionnements dans une chaîne logistique qui prend en compte la dimension transport. L'architecture industrielle étant distribuée, les mécanismes proposés cherchent à garantir à la fois, l'autonomie décisionnelle des entreprises constituant le réseau et aussi la convergence du processus. Le modèle proposé s'appuie sur une architecture multi agents et sur des mécanismes de négociation. Cette démarche utilise deux modèles mathématiques. Le premier vise à organiser la manière optimale de transport sous contraintes amont et aval. Le second modèle permet la recherche et le choix des prestataires de transport en optimisant le coût global. La méthode de résolution utilise un solveur muni d'une procédure par séparation et évaluation

Collaborative model for customer request ordering: research and selection of substitute suppliers

In this paper, we propose supplier research protocol and decision tools for supplier selection. The architecture of the negotiation and decision making is supported by a multi agent system and uses mixed integer programming models and solvers. The supply chain is composed by autonomous enterprises. Each enterprise must reach, in the same time, local and global goals. The research protocol is implemented in a virtual agent “Tier Negotiator Agent (TNA)” implanted in each tier of the supply chain, which provides human decision makers with data tables and suggests them to follow some directives. One TNA is activated each time a customer does not find sufficiently components for covering its needs and the protocol can activate TNA of upstream tiers

The time-consistent dial-a-ride problem

peer reviewedIn the context of door-to-door transportation of people with disabilities, service quality considerations such as maximum ride time and service time consistency are critical requirements. To identify a good trade-off between these considerations and economic objectives, we define a new variant of the multiperiod dial-a-ride problem called the time-consistent dial-a-ride problem. A transportation planning is supposed to be time consistent if for each passenger, the same service time is used all along the planning horizon. However, considering the numerous variations in transportation demands over a week, designing consistent plan for all passengers can be too expensive. It is therefore necessary to find a compromise solution between costs and time-consistency objectives. The time-consistent dial-a-ride problem is solved using an epsilon-constraint approach to illustrate the trade-off between these two objectives. It computes an approximation of the Pareto front, using a matheuristic framework that combines a large neighbourhood search with the solution of set partitioning problems. This approach is benchmarked on time-consistent vehicle routing problem literature instances. Experiments are also conducted in the context of door-to-door transportation for people with disabilities, using real data. These experiments support managerial insights regarding the inter-relatedness of costs and quality of service

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation