Simulation Optimization Using Soft Computing

To date, most of the research in simulation optimization has been focused on single response optimization on the continuous space of input parameters. However, the optimization of more complex systems does not fit this framework. Decision makers often face the problem of optimizing multiple performance measures of systems with both continuous and discrete input parameters. Previously acquired knowledge of the system by experts is seldom incorporated into the simulation optimization engine. Furthermore, when the goals of the system design are stated in natural language or vague terms, current techniques are unable to deal with this situation. For these reasons, we define and study the fuzzy single response simulation optimization (FSO) and fuzzy multiple response simulation optimization (FMSO) problems. The primary objective of this research is to develop an efficient and robust method for simulation optimization of complex systems with multiple vague goals. This method uses a fuzzy controller to incorporate existing knowledge to generate high quality approximate Pareto optimal solutions in a minimum number of simulation runs

Ruteo de vehículos - un problema de logística

Las investigaciones buscan optimizar el uso de los recursos para abaratar los costos de recoger o dejar mercancías, distribuir personal de mantenimiento y mejorar la eficiencia usando tecnologías de computación y comunicación. Los resultados se convierten en un software que puede ser transferido al sector productivo. Recoger o dejar mercancías y programar cuadrillas de empleados que instalan o reparan servicios públicos no es una tarea sencilla. No solo hay que planear las rutas de los vehículos y programar el personal de manera que no se pierda tiempo ni dinero, sino que durante el día deben atenderse nuevas órdenes en muchos sitios de la ciudad y hay que encajarlas en los recorridos previsto

Software para optimizar rutas de sistemas de buses como TransMilenio

Ingeniería y ciudadProdujeron un software apoyado en técnicas de optimización de gran escala y de optimización en redes, mediante el cual se intervienen las rutas, un componente estratégico de los sistemas de transporte, para optimizarlas en dos sentidos: en diseño con el fin de determinar cuál es la secuencia de paradas ideal, y en frecuencia para establecer cada cuánto deben pasar los buses por las estaciones. De esta manera podrían solucionarse muchos de los inconvenientes que enfrentan los usuarios cuando ven que algunos articulados vacíos no se detienen en estaciones atestadas de pasajeros o hay escasez de transporte hacia destinos de alta demanda y sobreoferta de rutas hacia lugares de baja ocupació

Optimizando la planeación en el sector público

La metodología presentada es una herramienta para priorizar la inversión pública que incorpora aspectos ténicos, económicos, financieros y sociales. Las organizaciones privadas se concentran principalmente en tomas las mejores decisiones para crear el máximo valor posible a sus accionistas. Por otra parte, las organizaciones públicas enfrentan un reto aún mayor: deben generar el máximo valor para toda la sociedad asignando eficientemente los siempre escasos recursos público

Méthodes de résolution et outils informatiques pour les tournées de véhicules dynamiques

Les activités de transport jouent un rôle crucial autant dans le domaine de la production que dans celui des services. En particulier, elles permettent d assurer la distribution de biens et de services entre fournisseurs, unités de production, entrepôts, distributeurs, et clients finaux. Plus spécifiquement, les problèmes de tournées de véhicules (VRP) considèrent la mise au point d un ensemble de tournées de coût minimal servant la demande en biens ou en services d un ensemble de clients distribués géographiquement, tout en vérifiant un ensemble de contraintes opérationnelles. Alors qu il s agissait d un problème statique, des avancées technologiques récentes permettent aux organisations de gérer leur flotte de véhicules en temps réel. Cependant, ces nouvelles technologies introduisent également une plus grande complexité dans les tâches de gestion de flotte, révélant une demande pour des outils d aide à la décision dédiés aux problèmes de tournées de véhicules dynamiques. Dans ce contexte, les contributions de la présente thèse de doctorat s organisent autour de trois axes : (i) elle présente un état de l art détaillé des problèmes de tournées dynamiques; (ii) elle introduit des frameworks d optimisation génériques adaptés à une grande variété de problèmes ; (iii) elle définit un problème de tournées novateur et aux nombreuses applications.Within the wide scope of logistics management,transportation plays a central role and is a crucialactivity in both production and service industry.Among others, it allows for the timely distributionof goods and services between suppliers, productionunits, warehouses, retailers, and final customers.More specifically, Vehicle Routing Problems(VRPs) deal with the design of a set of minimal costroutes that serve the demand for goods orservices of a set of geographically spread customers,satisfying a group of operational constraints.While it was traditionally a static problem, recenttechnological advances provide organizations withthe right tools to manage their vehicle fleet in realtime. Nonetheless, these new technologies alsointroduce more complexity in fleet managementtasks, unveiling the need for decision support systemsdedicated to dynamic vehicle routing. In thiscontext, the contributions of this Ph.D. thesis arethreefold : (i) it presents a comprehensive reviewof the literature on dynamic vehicle routing ; (ii)it introduces flexible optimization frameworks thatcan cope with a wide variety of dynamic vehiclerouting problems ; (iii) it defines a new vehicle routingproblem with numerous applications.NANTES-ENS Mines (441092314) / SudocSudocFranceF

A parallel matheuristic for the technician routing and scheduling problem

Article de revue (Article scientifique dans une revue à comité de lecture)International audienceThe Technician Routing and Scheduling Problem (TRSP) consists in routing staff to serve requests for service, taking into account time windows, skills, tools, and spare parts. Typical applications include maintenance operations and staff routing in telecoms, public utilities, and in the health care industry. In this paper, we present a formal definition of the TRSP, discuss its relation with the Vehicle Routing Problem with Time Windows (VRPTW), and review related research. From a method- ological perspective, we describe a matheuristic composed of a constructive heuristic, a parallel Adaptive Large Neighborhood Search, and a mathematical programming based post-optimization procedure that successfully tackles the TRSP. We validate the matheuristic on the Solomon VRPTW instances, where we achieve an average gap of 0.23 %, and matched 44 out of 55 optimal solutions. Finally, we illustrate how the matheuristic successfully solves a set of TRSP instances extended from the Solomon benchmark.&nbsp;</p

A fast re-optimization approach for dynamic vehicle routing

The present work deals with dynamic vehicle routing problems in which new customers appear during the design or execution of the routing. We propose a parallel Adaptive Large Neighborhood Search (pALNS) that produces high quality routes in a limited computational time. Then, we introduce the notion of driver inconvenience and define a bi-objective optimization problem that minimizes the cost of routing while maintaining its consistency throughout the day. We consider a problem setting in which vehicles have an initial routing plan at the beginning of the day, that is periodically updated by a decision maker. We introduce a measure of the driver inconvenience resulting from each update and propose a bi-objective approach based on pALNS that is able to produce a set of non-dominated solutions in reasonable computational time. These solutions offer different tradeoffs between cost efficiency and consistency, and can be used by the decision maker to update the routing of the vehicles introducing a controlled number of changes

On the Dynamic Technician Routing and Scheduling Problem

The Technician Routing and Scheduling Problem (TRSP) consists in routing staff to serve requests for service, taking into account time windows, skills, tools, and spare parts. Typical applications include maintenance operations and staff routing in telecoms, public utilities, and in the health care industry. In this paper we tackle the Dynamic TRSP (D-TRSP) in which new requests appear over time. We propose a fast reoptimization approach based on a parallel Adaptive Large Neighborhood Search (pALNS) and a Multiple Plan Approach (MPA). Finally, we present computational experiments on randomly generated instances

On the Technician Routing and Scheduling Problem

The technician routing and scheduling problem consists in routing and scheduling a crew of technicians in order to attend a set of service requests, subject to skill, tool, and spare part constraints. In this study we propose a formal definition of the problem and present a constructive heuristic and a large neighborhood search optimization algorithm