Modelación En Programación Matemática Y Resolución Del Problema De Localización-Ruteo En Logística Urbana

The implementation of urban distribution centers near to city centers to allow freight consolidation is a widely extended initiative worldwide, seeking to improve traffic congestion and quality of life in downtown, among others. This paper considers the problem of locating urban distribution centers and proposes an exact method, based on integer linear programming for strategic, tactical and operational decision-making. The aim is to solve, in an integer manner, location, sizing and operation (vehicle routing) problems in these logistics platforms. The model is validated using real-data taken from the city of SaintÉtienne, France. Computational experiments are also carried out in order to compare the proposed model with existing procedures from the literature. Results show the efficiency and effectiveness of the proposed model and its applicability in real decision-making for medium sized data sets

To develop an integrated model for green supply chain

Supply chain management is a set of techniques used for effective and efficient integration of suppliers, manufacturers, warehouses and dealers in such a way that system costs to be minimized and goods service needs to be realized with the correct number in the right place and at the right time. Since the important role of three factors of localization, routing and assignment is not covered in the survival of a supply chain life, therefore, integration of these factors will result in an effective supply chain. This research aims to study the issue of supply chain network design including the localization of facilities, allocation flow among facilities and routing decisions. The issue is to determine the number, location and capacity levels of distribution centers, to allocate customers to distribution centers and distribution centers to suppliers and routing decisions such as determination of the products transport route from distributors to customers and type of transport vehicles so that the total cost of the system to be minimized and customer coverage to be maximized. In addition to reducing costs and increasing quality, improving the environmental performance of the supply chain and decreasing the costs of environmental degradation is also included in the proposed issue.This necessity which is known as a green supply chain is observed by choosing vehicles with lower emissions and reducing transport distances.On the other hand, this research role includes the impact of sharing information through raising and reducing waiting times for carriers. All of the above will be formulated by an integer linear programming model. Given that the mentioned issue is located in the group of problems with hard complexity, this article suggests using multi-objective meta-heuristic algorithms for optimization of the problem and compares the efficiency of the proposed algorithms with each other using several random sample problems.Keywords: Localization, routing, allocation, green supply chain, sharing informatio

Modelación En Programación Matemática Y Resolución Del Problema De Localización-Ruteo En Logística Urbana

The implementation of urban distribution centers near to city centers to allow freight consolidation is a widely extended initiative worldwide, seeking to improve traffic congestion and quality of life in downtown, among others. This paper considers the problem of locating urban distribution centers and proposes an exact method, based on integer linear programming for strategic, tactical and operational decision-making. The aim is to solve, in an integer manner, location, sizing and operation (vehicle routing) problems in these logistics platforms. The model is validated using real-data taken from the city of SaintÉtienne, France. Computational experiments are also carried out in order to compare the proposed model with existing procedures from the literature. Results show the efficiency and effectiveness of the proposed model and its applicability in real decision-making for medium sized data sets

Patterns of location and hotel evolution: the case of Torremolinos

Torremolinos constituye un caso destacable que resalta la estrecha vinculación que existe entre el tipo de desarrollo turístico y los patrones de localización de la industria hotelera. Este estudio muestra la evolución de un destino maduro de sol y playa, que ha creado una notable oferta hotelera a lo largo del tiempo. Para comprender la distribución temporal y espacial de la oferta hotelera, se propone un modelo de localización de la actividad hotelera. Las herramientas de análisis utilizadas han sido la recopilación de la información documental y estadística relativa a los hoteles, las ortofotografías aéreas para el estudio de los cambios de usos del suelo, el análisis estadístico para conocer el comportamiento espacial y el trabajo de campo para localizar los establecimientos hoteleros. La investigación comprueba la existencia de clusters espaciales como estrategia de implantación del sector hotelero de Torremolinos.Proyecto de investigación “Crisis y reestructuración de los espacios turísticos del litoral español” (CSO2015-64468-P). Financiado por el Ministerio de Economía, Industria y Competitividad (Subdivisión de programas temáticos científico-técnico) y los Fondos FEDER (Unión Europea)

Facility location decisions under vehicle routing considerations

Cataloged from PDF version of article.Over the past few decades, the concept of integrated logistics system has emerged as a new management philosophy, which aims to increase distribution efficiency. Such a concept recognizes the interdependence among the location of facilities, the allocation of suppliers and customers to facilities and vehicle route structures around depots. In this study, in order to emphasize the interdependence among these, we build a model for the integration of location and routing decisions. We propose our model on realistic assumptions such as the number of vehicles assigned to each facility is a decision variable and the installing cost of a facility depends on how many vehicles will be assigned to that facility. We also analyze the opportunity cost of ignoring vehicle routes while locating facilities and show the computational performance of integrated solution approach. We propose a greedy type heuristic for the model, which is based on a newly structured savings function.Selçuk, BarışM.S

Solución de los problemas de localización y dimensionamiento de centros urbanos de distribución y enrutamiento de sus vehículos

50 páginasEn la mayoría de las grandes y medianas ciudades, las operaciones de transporte de mercancías tienen un impacto notable en la movilidad del tráfico urbano, así como en las actividades comerciales de la ciudad. La creación de centros urbanos de distribución cerca del centro de las ciudades para consolidar las cargas, es una iniciativa implementada alrededor del mundo que busca disminuir la congestión del tráfico vehicular en las calles y la calidad de vida sus habitantes. Este trabajo considera el problema de localizar los centros de distribución en las zonas urbanas y propone un enfoque para la toma de decisiones a nivel estratégico, táctico y operativo. Se busca resolver, de manera integral, los problemas de localización, dimensionamiento y operación (ruteo de camiones) en estas terminales logísticas. El enfoque es validado usando datos de la vida real provenientes de la ciudad de SaintÉtienne, Francia. Así mismo, se realizan comparaciones experimentales con procedimientos existentes en la literatura. Los resultados muestran la eficiencia y efectividad del enfoque propuesto y su aplicabilidad en la realidad, para instancias hasta de tamaño grande donde, las salidas del enfoque, deben ser analizadas por el tomador de decisiones y pueden mejorar la competitividad del sistema logístico y las condiciones ambientales y sociales de la ciudad en cuestión

Solución de problemas estocásticos de localización-ruteo

96 Páginas.El problema de localización-ruteo estocástico (SLRP por sus siglas en inglés) es un problema muy común en empresas de manufactura, comercializadoras y transportadoras. El problema consiste en simultáneamente localizar uno o varios depósitos centrales entre un conjunto de ubicaciones potenciales, determinar un tamaño de flota y diseñar rutas para cada unos de los vehículos para visitar un conjunto de clientes considerando la incertidumbre que existe en algunos aspectos de la operación. En las soluciones presentadas en la literatura para este tipo de problemas se ha considerado mayoritariamente soluciones determinísticas o las soluciones estocásticas presentadas solo consideran en su mayoría la demanda como componente estocástico del sistema. La presente investigación propone un modelo para resolver la versión estocástica con incertidumbre en los costos de transporte y velocidades de los vehículos a través de un enfoque jerárquico de dos fases basado tanto en optimización como en simulación de eventos discretos. Se presenta una estrategia de selección aleatoria en la fase de localización; la fase de ruteo se resuelve empleando un algoritmo basado en colonia de hormigas, y finalmente se incluye al modelo el comportamiento estocástico del sistema a través de simulación de eventos discretos. Se presenta un análisis comparativo para validar la calidad de las soluciones obtenidas por el algoritmo y se realiza un estudio experimental permitiendo el análisis estadístico de resultados. Los resultados obtenidos permiten validar el presente enfoque como una buena herramienta de apoyo a la toma de decisiones para la localización de centros de distribución, la determinación de flotas de vehículos, la asignación de zonas de servicio y el ruteo de vehículos

Ordered Weighted Average optimization in Multiobjective Spanning Tree Problem

Rework adversely impacts the performance of building projects. In this study, data were analyzed from 788 construction incidents in 40 Spanish building projects to determine the effects of project and managerial characteristics on rework costs. Finally, regression analysis was used to understand the relationships among contributing factors and to develop a model for rework prediction. Interestingly, the rework prediction model showed that only the original contract value (OCV) and the project location in relation to the company’s headquarters contributed to the regression model. Project type, type of organization, type of contract, and original contract duration (OCD), which represents the magnitude and complexity of a project, were represented by the OCV. This model for rework prediction based on original project conditions enables strategies to be put in place prior to the start of construction, to minimize uncertainties, to reduce impacts on project cost and schedule, and, thus, to improve productivity.Peer ReviewedPostprint (author's final draft

Problemas de localização-distribuição de serviços semiobnóxios: aproximações e apoio à decisão

Doutoramento em Gestão IndustrialA presente tese resulta de um trabalho de investigação cujo objectivo se centrou no problema de localização-distribuição (PLD) que pretende abordar, de forma integrada, duas actividades logísticas intimamente relacionadas: a localização de equipamentos e a distribuição de produtos. O PLD, nomeadamente a sua modelação matemática, tem sido estudado na literatura, dando origem a diversas aproximações que resultam de diferentes cenários reais. Importa portanto agrupar as diferentes variantes por forma a facilitar e potenciar a sua investigação. Após fazer uma revisão e propor uma taxonomia dos modelos de localização-distribuição, este trabalho foca-se na resolução de alguns modelos considerados como mais representativos. É feita assim a análise de dois dos PLDs mais básicos (os problema capacitados com procura nos nós e nos arcos), sendo apresentadas, para ambos, propostas de resolução. Posteriormente, é abordada a localização-distribuição de serviços semiobnóxios. Este tipo de serviços, ainda que seja necessário e indispensável para o público em geral, dada a sua natureza, exerce um efeito desagradável sobre as comunidades contíguas. Assim, aos critérios tipicamente utilizados na tomada de decisão sobre a localização destes serviços (habitualmente a minimização de custo) é necessário adicionar preocupações que reflectem a manutenção da qualidade de vida das regiões que sofrem o impacto do resultado da referida decisão. A abordagem da localização-distribuição de serviços semiobnóxios requer portanto uma análise multi-objectivo. Esta análise pode ser feita com recurso a dois métodos distintos: não interactivos e interactivos. Ambos são abordados nesta tese, com novas propostas, sendo o método interactivo proposto aplicável a outros problemas de programação inteira mista multi-objectivo. Por último, é desenvolvida uma ferramenta de apoio à decisão para os problemas abordados nesta tese, sendo apresentada a metodologia adoptada e as suas principais funcionalidades. A ferramenta desenvolvida tem grandes preocupações com a interface de utilizador, visto ser direccionada para decisores que tipicamente não têm conhecimentos sobre os modelos matemáticos subjacentes a este tipo de problemas.This thesis main objective is to address the location-routing problem (LRP) which intends to tackle, using an integrated approach, two highly related logistics activities: the location of facilities and the distribution of materials. The LRP, namely its mathematical formulation, has been studied in the literature, and several approaches have emerged, corresponding to different real-world scenarios. Therefore, it is important to identify and group the different LRP variants, in order to segment current research and foster future studies. After presenting a review and a taxonomy of location-routing models, the following research focuses on solving some of its variants. Thus, a study of two of the most basic LRPs (capacitated problems with demand either on the nodes or on the arcs) is performed, and new approaches are presented. Afterwards, the location-routing of semi-obnoxious facilities is addressed. These are facilities that, although providing useful and indispensible services, given their nature, bring about an undesirable effect to adjacent communities. Consequently, to the usual objectives when considering their location (cost minimization), new ones must be added that are able to reflect concerns regarding the quality of life of the communities impacted by the outcome of these decisions. The location-routing of semi-obnoxious facilities therefore requires to be analysed using multi-objective approaches, which can be of two types: noninteractive or interactive. Both are discussed and new methods proposed in this thesis; the proposed interactive method is suitable to other multi-objective mixed integer programming problems. Finally, a newly developed decision-support tool to address the LRP is presented (being the adopted methodology discussed, and its main functionalities shown). This tool has great concerns regarding the user interface, as it is directed at decision makers who typically don’t have specific knowledge of the underlying models of this type of problems