A single-producer multi-retailer integrated inventory model with a rework process

This study considers a single-producer multi-retailer integrated inventory model with the reworking of random defective items produced. The objective is to find the optimal production lot size and optimal number of shipments that minimizes total expected costs for such a specific supply chains system. It is assumed that a product is manufactured by a producer. All items are screened for quality purpose and random nonconforming items will be picked up and reworked at the end of regular production in each cycle. After the entire lot is quality assured, multiple shipments will be delivered synchronously to m different retailers in each production cycle. Each retailer has its own annual product demand, unit stock holding cost, and fixed and variable delivery costs. Mathematical modeling and analysis is used to deal with the proposed model and to derive the expected system cost. Hessian matrix equations are employed to prove the convexity of the cost function. As a result, a closed-form optimal replenishment-delivery policy for such a specific single-producer multi-retailer integrated inventory model is obtained. A numerical example is provided to show the practical usage of the proposed model

Revisiting "integrating a cost-reduction shipment plan into a single-producer multi-retailer system with rework" using an alternative approach

This study revisits a single-producer multi-retailer system with a cost-reduction shipment plan and rework [1] using an alternative approach. Unlike the conventional method that uses differential calculus on system cost function to prove its convexity and derive the optimal production-shipment policy, we proposed an algebraic solution procedure to the problem. Such a straightforward approach may enable the practitioners with little knowledge of calculus to understand real supply chain systems more easily

An operational policy for a single vendor multi buyer integrated inventory supply chain system considering shipping time

Since its introduction, the concept of integrated inventory supply chain has received a considerable amount of attention. The majority of studies in the last three decades revealed an increase in holding cost as product moves further down the chain or up the chain. A recent study Hoque (2008) considered vendor’s setup cost and inventory holding cost. Some research also considered fixed transportation cost, which is unrealistic. This study focuses on a single-vendor, multi-buyer scenario and presents three models. First, two models illustrate the transferring of equally-sized batches. Then, a third model considers the transferring of unequally-sized batches in a lot. This study relaxes the assumption that vendor’s holding cost must be greater than or less than all buyer’s holding costs in the system. Also, this research facilitates unequal transportation time and cost for different buyers for greater flexibility. The total system cost is calculated by summing the annual operational cost for all the parties in the system. Optimum values of the decision variables are determined using a direct search method. As presented by the third model, a numerical example demonstrates that the total system cost is less when compared with other two models presented. This study also presents the following: solution procedures to solve each model, many numerical examples to support mathematical findings, and performance comparisons among three findings. In order to justify the lot-splitting approach for solving the integrated inventory problem, alternative models with no lot splitting are devised and tested under the same circumstances. Alternative models with no lot splitting produce similar or better results. Under the same circumstances, the alternate third model is observed to be offering the least total cost for the system. This study also presents a sensitivity analysis to check the robustness of the three models. The future extension of this research may involve considering storage capacity constraint and random demand

Inventory Management and Supply Chain Coordination Mechanisms

This dissertation is on inventory management and supply chain coordination mechanisms within an economic order quantity framework. Specifically, this research focuses on modeling optimal order policies and coordination mechanisms for a supply chain involving items which experience probabilistic failure during storage. These items are common types of manufactured items which, nonetheless, require specialized order policy considerations due to their unique characteristics. We first develop the solution for the buyer’s problem through the use of an economic order quantity (EOQ) model incorporating item failure. We then proceed to model the manufacturer’s problem through the use of an economic production quantity (EPQ) model. Finally, we consider mechanisms to promote mutually-beneficial cooperation between the supplier and n buyers in service of coordinating the entire supply chain. While prior research has focused on items which can be repaired or sold at a discount upon failure, such models are inappropriate for systems where repair costs exceed or are equivalent to item costs and imperfect items are unacceptable. Examples of industries featuring these inventory conditions include the medical, defense, and electronics industries where defective items are largely useless. First, our EOQ model considers a buyer-supplier relationship featuring delivery and stocking of items which experience probabilistic failure in storage. Thereafter, our EPQ model considers in-house production of such items. Collectively, our EOQ and EPQ models provide methods for developing optimal order policies necessary to achieve practicable supply chain coordination. In order to validate the necessity of the developed models, we include an empirical analysis of item reliability for some common mechanical components used in the defense industry, thereby identifying items which fail in the manner modeled in this dissertation. Having considered optimal order policies for both buyers and suppliers, we next develop an optimal solution for a coordinated supply chain. The proposed solution allows the manufacturer to coordinate a supply chain consisting of n buyers in order to achieve a common replenishment time. Through this optimization framework, we minimize total system-wide costs and derive the cost savings associated with our coordinated solution. Numerical examples are then used to demonstrate the magnitude of cost savings achievable through our coordination framework. We conclude by proposing several mechanisms for leveraging the resulting cost savings to induce mutually-beneficial cooperation between the supplier and multiple buyers. Given the lack of buyer-supplier cooperation noted in empirical research related to supply chain coordination, our identification of specific mechanisms useful for inducing mutually-beneficial cooperation between buyers and suppliers represents an important practical contribution to the supply chain coordination literature. These models are accompanied by a thorough overview and discussion of economic order quantity theory, optimal order policies, and supply chain coordination mechanisms.Ph.D., Business Administration -- Drexel University, 201

Propuesta de un modelo de gestión en logística humanitaria para el cuerpo de Infantería de Marina de la Armada Nacional de Colombia : caso inundaciones en el departamento de Bolívar /

Con esta investigación se buscó responder al siguiente planteamiento ¿Cuál es el modelo de gestión en logística humanitaria más apropiado para el cuerpo de Infantería de Marina de la Armada Nacional de Colombia en el marco de la atención de inundaciones del departamento de Bolívar? Para tal fin, fueron definidos un objetivo general y siete objetivos específicos que condujeron al diseño del modelo que se presenta en los apartados siguientes. No obstante, como paso previo a la exposición de los componentes del Modelo, es preciso aclarar algunos aspectos que dieron lugar a su definición, los cuales además, dan cuenta de su alcance y de sus fundamentos. En primer lugar, el Modelo propuesto considera como zona geográfica de priorización a la Ecorregión del Plano Inundable de la Depresión Momposina (Ecorregión Inundable de la Llanura Fluvio-deltáica de los ríos Cauca, Magdalena y San Jorge). Concretamente los municipios identificados como de mayor vulnerabilidad ante las inundaciones: Margarita, San Fernando, Regidor, Hatillo de Loba, El Peñón, Mompóx, Cicuco, Pinillos, Achí y Talaigua Nuevo, San Jacinto del Cauca, Altos del Rosario, Río Viejo y Magangué. En segundo lugar, el Modelo se sustenta en: -El análisis realizado a los elementos fundamentales de la Logística Humanitaria, en la estructura del Consejo Departamental de Gestión de Riesgo de Desastres del departamento de Bolívar del cual hace parte la Infantería de Marina. -El rol y las funciones que le han sido atribuidas a la Infantería de Marina en el marco de su participación en el Consejo Departamental de Gestión de Riesgo de Desastres de Bolívar. El Plan de Gestión del Riesgo de Desastres del departamento de Bolívar contempla tres procesos esenciales: el conocimiento del riesgo, la reducción del riesgo y el manejo de los desastres. En estos procesos, la Infantería de Marina actúa, principalmente, en el manejo de los desastres, haciendo parte de la Comisión operativa del Consejo que se encarga de coordinar y generar las acciones relacionadas con el desarrollo de planes logísticos para la distribución de albergues temporales, alimentos, y demás elementos que llegase a necesitar la comunidad.Incluye referencias bibliográficas (páginas 115-128

Diseño de una estrategia de gestión de inventarios colaborativos para escenarios de incertidumbre de una cadena de suministro multi-nivel : caso aplicación sector madera y muebles de la Región Caribe de Colombia /

Son muchos los retos a los que las empresas deben enfrentarse hoy en día. La creciente competitividad y los fenómenos de globalización en la actualidad, exige a las empresas, el diseño de estrategias y respuestas cada vez más eficientes en la gestión de los procesos, que les permitan sobrevivir y crecer en un mundo en continuo cambio, en el cual el cliente es quien asume cada vez más el poder de negociación y quien al final define el éxito o fracaso de todo el engranaje empresarial (Cadena de Suministro) que se encuentra tras la fabricación de un producto. Para los expertos en administración de negocios, no basta sólo con hacer las cosas bien, es necesario ser excelentes. El concepto de cadena de suministro aparece por primera vez en los estudios de Forrester cuando manifestó que el éxito de las empresas dependía de la interacción entre los flujos de información, materiales, pedidos, dinero, mano de obra y equipos, y que la comprensión y control de estos flujos es el principal trabajo de la gestión. La cadena de suministro representa una red de trabajo para las funciones de abastecimiento de material, su transformación en productos terminados y la distribución de esos productos a los clientes finales (Lee & Billington, 1993), en este sentido, es un sistema integrado que sincroniza una serie de procesos: adquisición de materiales, transformación de materiales y partes en productos terminados, agregar valor a estos productos, distribuir y entregar estos los productos a minoristas y clientes finales y facilitar el intercambio de información entre los grupos de interés de la cadena, cuyo objetivo principal es aumentar la eficiencia de las operaciones, productividad y ventajas competitivas frente a sus competidores. Por otro lado, típicamente está compuesta de dos procesos de negocios principales: i) Gestión de Materiales, concebida como la adquisición y almacenamiento de materia prima, partes y suministros, y soporta el ciclo completo del flujo de materiales desde compras y el control de los materiales de producción para la planeación y control de trabajo en proceso, hasta el almacenamiento, venta y distribución de los productos finales (Johnson & Malucci, 1999) y ii) Distribución Física, que contiene todas las actividades logísticas de salida para atender a los clientes, e incluyen la recepción y procesamiento de órdenes, despliegue de inventarios, mantenimiento y manejo de inventarios, transporte, consolidación, precios, promociones, devoluciones y el soporte al ciclo de vida de producto (Bowersox & Closs, 1996), es por eso que Incrementar la eficiencia de los procesos entre las empresas es una alternativa prioritaria para reducir costos, mejorar la calidad y agilizar las operaciones.Incluye anexosIncluye bibliografí

Supply Chain

Traditionally supply chain management has meant factories, assembly lines, warehouses, transportation vehicles, and time sheets. Modern supply chain management is a highly complex, multidimensional problem set with virtually endless number of variables for optimization. An Internet enabled supply chain may have just-in-time delivery, precise inventory visibility, and up-to-the-minute distribution-tracking capabilities. Technology advances have enabled supply chains to become strategic weapons that can help avoid disasters, lower costs, and make money. From internal enterprise processes to external business transactions with suppliers, transporters, channels and end-users marks the wide range of challenges researchers have to handle. The aim of this book is at revealing and illustrating this diversity in terms of scientific and theoretical fundamentals, prevailing concepts as well as current practical applications