Diseño de un modelo de inventarios para la operación logística de una compañía farmaceutica

Ingeniería y Universidad 9(1).

ABSTRACT Resumen: En este artículo se analiza la problemática encontrada en el proceso de planeación de demanda e inventarios de una compañía multinacional perteneciente al sector farmacéutico en Bogotá, Colom-bia. Se parte de un diagnóstico cuantitativo de los procesos e indicado-res logísticos para luego analizar y proponer un modelo de inventarios resultante de la modificación de la heurística propuesta por Hopp, Spearman y Zhang [1997] para ser adaptado a las políticas y realidad organizacional de la empresa. Finalmente se presenta la aplicación del modelo propuesto sobre unos datos pilotos y los resultados que se pre-sentaron en términos de reducción de existencias y mejoramiento del nivel de servicio. Abstract: In this paper the problems encountered in the supply and demand planning process in a multinational pharmaceutical company in Bogotá, Colombia, are analyzed. It begins with a qualitative diagno-sis of the key process logistics indicators in order to analyze and propose an inventory model as the result of the use of the heuristic proposed by Hopp, Spearman y Zhang [1997] with the intention to adapt it to the politics and conditions of an specific firm. Finally, the results of the application of the model to pilot data are presented showing an important reduction in inventories and increases in the service level.

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    ABSTRACT: This work was initiated and supported by a manufacturer of mail processing equipment, which stocks 30,000 distinct parts in a distribution center to support field maintenance of their equipment. To find an effective stocking policy for this system, we formulate a constrained optimization model with the objective of minimizing overall inventory investment at the distribution center subject to constraints on customer service and order frequency. Because size, integrality, and nonconvexity make this problem intractable to exact analysis, we develop three heuristic algorithms based on simplified representations of the inventory and service expressions. These lead to what we call easily implementable inventory policies, in which the control parameters for a newly introduced part can be computed in closed form without reoptimizing the rest of the system. Numerical comparisons against a lower bound on the cost function show that even our simplest heuristic works well when a high service level is required. However, we show that a more sophisticated heuristic is more robustly accurate. We also compare our heuristics to methods previously in use by the firm whose system motivated this research and show that they are more efficient in the sense of attaining the same customer service level with a 20-25% smaller inventory investment. Finally, we discuss implementation issues related to the specific needs of the client firm, such as how to handle parts with no or low recent usage and dynamically changing demand for parts.
    Operations Research 06/1997; 45(3):327-340. DOI:10.1287/opre.45.3.327 · 1.50 Impact Factor

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Jan 15, 2015