Distribution is one of the most important processes in a supply chain, given that it represents u... more Distribution is one of the most important processes in a supply chain, given that it represents up to two thirds of company logistics costs and up to 20% of the total cost of products. For that reason, it is essential to optimize the costs of distribution. A steel producer located in Monterrey distributes their products to different parts of Mexico. Currently, the distribution is carried out through empirical knowledge, underusing resources and generating unnecessary costs. The aim is to undertake the distribution process more efficiently. This paper presents an optimization model based on vehicle routing problem (VRP), for the distribution of heavy pipes taking into account the company's own characteristics, such as: rented heterogeneous fleet, multiple shipments of products, split deliveries and open cycles (meaning that the routes may not necessarily end in the depot).
In this paper we show the importance of applying mathematical optimization when designing the dis... more In this paper we show the importance of applying mathematical optimization when designing the distribution network in a supply chain, specifically in making decisions related location of facilities and inventory management, which are associated with different levels of planning but are closely related. The addressed problem is an extension of the classic capacitated facility location problem. The distinguishing features are: the inventory management, the presence of multiple plants, and the single source constraints in both echelons. A key issue is that demand at each distribution center is a function of the demands at the retailers assigned, which is a random variable whose value is not known at the time of designing the network. We focus on the mathematical modeling of the problem and the evaluation of the performance of the developed models, so, it can be observed the troubles that arise when modeling supply chains that consider different types of decisions. Keywords: Supply chain, location and inventory problem, mixed integer nonlinear programming, mixed integer linear programming. RESUMEN En este artículo se muestra la importancia de la optimización matemática en el diseño de una cadena de suministros, específicamente en la toma de decisiones dentro de un problema de localización de instalaciones y un problema de inventarios. Dichas decisiones pertenecen a diferentes niveles de planeación aun así se encuentran estrechamente relacionadas. El problema es una extensión del clásico problema de localización de instalaciones capacitadas. Las características destacadas son: el manejo de inventarios, la presencia de múltiples plantas y las restricciones de única fuente en ambos niveles de la cadena. Un punto clave en la investigación consiste en definir la demanda de los centros de distribución como función de la demanda de los minoristas asignados, la cual es una variable aleatoria, cuyo valor es desconocido al momento de diseñar la red de distribución. Nos enfocamos en la modelación matemática del problema y en la evaluación del desempeño de los modelos desarrollados, de manera que es posible observar la dificultad que involucra modelar cadenas de suministros que consideran diferentes tipos de decisiones.
In the two-stage capacitated facility location problem a single product is produced at some plant... more In the two-stage capacitated facility location problem a single product is produced at some plants in order to satisfy customer demands. The product is transported from these plants to some depots and then to the customers. The capacities of the plants and depots are limited. The aim is to select cost minimizing locations from a set of potential plants and depots. This cost includes fixed cost associated with opening plants and depots, and variable cost associated with both transportation stages. In this work a Lagrangian relaxation is analyzed and a Lagrangian heuristic producing feasible solutions is presented. The results of a computational study are reported.
Distribution is one of the most important processes in a supply chain, given that it represents u... more Distribution is one of the most important processes in a supply chain, given that it represents up to two thirds of company logistics costs and up to 20% of the total cost of products. For that reason, it is essential to optimize the costs of distribution. A steel producer located in Monterrey distributes their products to different parts of Mexico. Currently, the distribution is carried out through empirical knowledge, underusing resources and generating unnecessary costs. The aim is to undertake the distribution process more efficiently. This paper presents an optimization model based on vehicle routing problem (VRP), for the distribution of heavy pipes taking into account the company's own characteristics, such as: rented heterogeneous fleet, multiple shipments of products, split deliveries and open cycles (meaning that the routes may not necessarily end in the depot).
In this paper we show the importance of applying mathematical optimization when designing the dis... more In this paper we show the importance of applying mathematical optimization when designing the distribution network in a supply chain, specifically in making decisions related location of facilities and inventory management, which are associated with different levels of planning but are closely related. The addressed problem is an extension of the classic capacitated facility location problem. The distinguishing features are: the inventory management, the presence of multiple plants, and the single source constraints in both echelons. A key issue is that demand at each distribution center is a function of the demands at the retailers assigned, which is a random variable whose value is not known at the time of designing the network. We focus on the mathematical modeling of the problem and the evaluation of the performance of the developed models, so, it can be observed the troubles that arise when modeling supply chains that consider different types of decisions. Keywords: Supply chain, location and inventory problem, mixed integer nonlinear programming, mixed integer linear programming. RESUMEN En este artículo se muestra la importancia de la optimización matemática en el diseño de una cadena de suministros, específicamente en la toma de decisiones dentro de un problema de localización de instalaciones y un problema de inventarios. Dichas decisiones pertenecen a diferentes niveles de planeación aun así se encuentran estrechamente relacionadas. El problema es una extensión del clásico problema de localización de instalaciones capacitadas. Las características destacadas son: el manejo de inventarios, la presencia de múltiples plantas y las restricciones de única fuente en ambos niveles de la cadena. Un punto clave en la investigación consiste en definir la demanda de los centros de distribución como función de la demanda de los minoristas asignados, la cual es una variable aleatoria, cuyo valor es desconocido al momento de diseñar la red de distribución. Nos enfocamos en la modelación matemática del problema y en la evaluación del desempeño de los modelos desarrollados, de manera que es posible observar la dificultad que involucra modelar cadenas de suministros que consideran diferentes tipos de decisiones.
In the two-stage capacitated facility location problem a single product is produced at some plant... more In the two-stage capacitated facility location problem a single product is produced at some plants in order to satisfy customer demands. The product is transported from these plants to some depots and then to the customers. The capacities of the plants and depots are limited. The aim is to select cost minimizing locations from a set of potential plants and depots. This cost includes fixed cost associated with opening plants and depots, and variable cost associated with both transportation stages. In this work a Lagrangian relaxation is analyzed and a Lagrangian heuristic producing feasible solutions is presented. The results of a computational study are reported.
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Papers by Miguel Mata