Desarrollo metodológico para la optimización de la cadena de suministro esbelta con m proveedores y n demandantes bajo condiciones de incertidumbre: caso aplicado a empresas navieras colombianas

La tesis propone una metodología que incluye caracterización, diagnóstico identificación y análisis de parámetros de la operación logística del sector naval colombiano, sumado al diseño, configuración y pruebas de modelos de programación lineal entera mixta utilizados para atender coordinadamente decisiones estratégicas sobre gestión de flota, proveedores, transporte y almacenamiento en este sector básico de la economía del país. Se definieron políticas y estrategias soportadas en los modelos matemáticos codificados en el lenguaje de programación algebraica GAMS, con interface en Visual Basic–Excel que permite realizar análisis de sensibilidad. La evaluación y pruebas de los modelos demuestran la bondad que tienen éstos en las decisiones logísticas para este sector, el cual de acuerdo con el diagnóstico merece especial y urgente atención dado los niveles de servicio y rendimiento que presentan sus procesos logísticos. Finalmente se presentan resultados numéricos que establecen propiedades, ventajas y desventajas de cada uno de los modelos, incluyendo el análisis de las externalidades generadas por la operación logística./Abstract. The thesis proposes a methodology which includes characterization, identification and analysis of diagnostic parameters of the operation logistics Colombian naval sector, together with the design, configuration and testing models of mixed integer linear programming used to serve a coordinated strategic decision on fleet management, suppliers transport and storage in the basic sector of the economy. They supported policies and strategies defined in mathematical models coded in the GAMS algebraic programming language with Visual Basic–Excel interface that enables sensitivity analysis. The evaluation and testing of the models show the goodness they have in logistics decisions for this sector, which according to the diagnosis deserves special and urgent attention given the levels of service and performance traits that present logistical challenges. We present numerical results that set properties, advantages and disadvantages of each of the models put forward, including the assessment of externalities generated by the logistics operation.Doctorad

Barreras y facilitadores para la implementación de cadenas de suministro sostenibles en la industria naval

Sustainability is a topic of interest on the agenda of governments, companies and academics worldwide. Changing practices in supply chain management to decrease environmental and social impact has become more important. The shipping industry is also facing these challenges and is looking to incorporate new technologies and processes for supply chain management. However, depending on the context, previous studies have identified different factors that influence the successful implementation of sustainable practices. The objective of this study is to review the barriers and facilitators that influence the implementation of sustainable supply chain management policies in the shipping industry through a literature review and evaluate their relationships.La sostenibilidad es un tema de interés en la agenda de los gobiernos, las empresas y académicos a nivel mundial. Cambiar las prácticas en la gestión de la cadena de suministro para disminuir el impacto ambiental y social se ha vuelto más importante. La industria naval se enfrenta también a estos desafíos, por lo que busca la incorporación de nuevas tecnologías y procesos para la gestión de su cadena de suministro. Sin embargo, dependiendo del contexto estudios previos han identificado diferentes factores que influyen en el éxito de la implementación de prácticas sostenibles. El objetivo de este estudio es realizar una revisión sobre las barreras y facilitadores que influyen en la implementación de políticas de gestión sostenible de la cadena de suministro en la industria naval a través de una revisión de literatura y evaluar sus relacione

Gestión de Inventarios para distribuidores de productos perecederos

This paper considers the problem of determining the best inventory managementpolicy for perishable products on fish trading companies. Themain objective is to determine the inventory management policy withsafety stock for a probabilistic model, which maximizes the expected dailyprofit by considering the product, by considering that the products areperishables and only could be stored for a maximum number of days.This paper proposes a methodology based on Montecarlo simulation.Computational experiments using real world data from a fish tradingcompany in the Colombian market shows the efficiency and the effectivenessof the proposed methodology based on the maximization of theaverage net profit.Este artículo considera el problema de determinar la mejor política deadministración de inventarios para productos perecederos en compañíascomercializadoras de pescado. El objetivo fundamental es encontrar lapolítica de inventario con stock de seguridad para un modelo probabilísticoque maximice la utilidad diaria esperada, considerando que los productosson perecederos y, por lo tanto, solo pueden estar almacenados por unmáximo número de días. Se propone una metodología basada en SimulaciónMontecarlo. Experimentos computacionales usando instancias realesobtenidas de una compañía comercializadora de pescado en el mercadocolombiano muestran la eficiencia y la efectividad de la metodologíapropuesta basada en la maximización de utilidad neta esperada

Consumo de insumos agroindustriales por el subsector panificador de palmira, valle del cauca.

Los indicadores de consumo agroindustrial en las Pymes del subsector panificador resultan apremiantes para el diseño de estrategias de sostenibilidad para los pequeños artesanos del pan. Se evaluaron los subsistemas administrativos, talento humano y operativo en 30 de las 178 organizaciones que conformaron el subsistema panificador de Palmira en el 2005. El consumo estimado anual para el 2004 de harina de trigo fue 2.016 t; 348 t de azúcar; 240 t de queso; 54 t de sal; 492 t de margarina; 99 t de levadura; 151.200 paneles de huevos. En materias primas auxiliares consume 384.000 m3 de gas natural; 1.2 millones de kw de energía eléctrica y 156.000 m3 de agua. El sector genera 681 empleos directos. Se presenta mapa con la ubicación del 86% de las panaderías registradas en la Cámara de Comercio. No existe una sola panadería que en forma integral haya implementado un programa de Buenas Prácticas de Manufactura-BPM, que cumpla con las normas del (INVIMA), que disponga de un sistema de Análisis de Peligros y Puntos Críticos de Control (HACCP), que esté certificada con normas sobre aseguramiento de calidad (ISO 9000), y/o Gestión Ambiental (ISO 14000), con programas de salud ocupacional (OHSAS 18000) y programas de mejora permanente en aspectos administrativos y comerciales.The indicators of agroindustrial consumption in the bakers subsector Pymes play a primary role for designing sustainable strategies for the small craftsman of bread. The administrative, operative and human talent subsystems were evaluated, in 30 of 178 organizations that conformed the bakers subsystems of Palmira on 2005. The estimated annual consumption of wheat flour on 2004 was 2016 t; 348 t of sugar; 240 t of cheese; 54 t of salt; 492 t of margarine; 99 t of yeast; 151200 panels of eggs. With regarding to raw materials it consumes 384000 m3 of natural gas; 1.2 million kw of electric power and 156000 m3 of water. The sector generates 681 direct employments. Map is presented with the location of 86% of the bakeries registered in the Trade Chamber. There is not a unique bakery that had implemented a program of Good Manufacture Practices BPM in an integral way, that meets the National Institute of Medications and Foods Surveillance INVIMA Standars, that has of a system of Hazard Analysis and Critical Control Point (HACCP) or have been is to be certified with Quality Assuring Standars (ISO 9000), and/or Environmental Administration (ISO 14000), with occupational health programs (OHSAS 18000) and permanent improvement programs relative to administrative and commercial aspects

Coordination of inventory: a case study of city logistics

The managerial organizations are betting to have best results by means utilization collaborative processes and coordinated with her strategic partners. Researchers that study logistics are concentrating the design of new methodologies, methods, techniques and tools that they allow managing adequately the policies for demand driven supply network. The objective of this paper is to propose a methodology that managed as a project the coordination of inventory for multiproduct with multiple companies for the optimization the costs joint logistics in an operating context of urban distribution of goods demand driven. The decisional vision of this methodology is based in the model of periodic review of economic order interval for multiple items extended to a system just in time that in general, consists of determining a common replenishment epoch for the efficient charging unit homogenizing its stock keeping unit in two containers base ten for the model of physical distribution between a supplier and multiple buyers. Finally, was tested in a company leader in the manufacture of parts for vehicles of Bogotá D.C achieving improve joint logistics costs of storage up to 0.85 points absolute in comparison with his own model of accounting cost the service of the storage, allowing him to estimate the unitary benefits of the service provided the inventory management in 1,7 USD/m2-month by warehouse position and the 2 USD/m2-month by container

Supply Chain Network Design of Perishable Food in Surplus Periods

Research on the design of the perishable food supply chain network has increased in recent years. However, little attention has been given to those seasonal foods that generate periods of oversupply and, particularly, to their impact on the sustainability of small producers in developing countries. This research proposes and develops a multi-objective mixed linear programming model for perishable fruits in a south American country at oversupply periods. It minimizes losses and transportation costs and maximizes the inclusion of farmers. It considers four echelons of the supply chain: farms, collection centers, distribution centers and the demand, which is represented by the agroindustry, wholesalers, shopkeepers, and hypermarkets. The Epsilon constraint method is used to solve the multi-objective model. A set of Pareto optimal solutions helped evaluate tradeoffs between the three objectives and find the location of collection and distribution centers. The proposed generic mathematical model is applicable to any food supply chain, as it allows for the improvement of the established performance measures and the distribution flows for the different echelons. The model considers the losses in perishable food from the impacts caused by changes in temperature (T0) and humidity level (RH) at different thermal floors of mountain ranges

Last mile logistics in mega-cities for perishable fruits

Purpose: A common problem in mega cities is congestion, due to the size of the automotive park, this makes that the perishable foods decreasing their organoleptic characteristics or increases their losses, which requires considering the effect of time on routing problems. The state of the art demonstrates the need to formulate new routing models that include the specific characteristics of perishable foods in order to reduce their losses. Design/methodology/approach: A mathematical model was formulated based on two classical models: the three-index vehicle flow model proposed by (Golden, Assad, Levy & Gheysens, 1984) and the time window model proposed by (Cordeau, Desaulniers, Desrosiers, Solomon & Soumis, 1999). We proposed a novel VRP Model that permits reductions loss due to the perishable. Findings: The optimum cost is found with AMP® for twenty nodes, six vehicles and six fruits. For more nodes, a two-phase strategy is proposed, first a clustering based on a modified p-median model and then a VRP for each cluster. Research limitations/implications: The results showed the need to investigate multi-objective models, since the performance measures can be efficiency, quality and response capacity; the model can be applied in other supply chains of perishable foods. Social implications: According to FAO in Logistics practices in the last mile generate between 10-30% of the perishable food loss in developing countries’ mega-cities. Originality/value: A last-mile logistics strategy is proposed to manage delivery routes for fresh fruits in mega-cities, considering the effect of congestion through travel time in the perishability function. The new model it uses the flow variable to control the amount of each fruit arriving to each node and the time variable to define fruit waste or loss depending on the time and type of fruit.Peer Reviewe

An algorithm for the routing problem with split deliveries and time windows (sdvrptw) applied on retail sme distribution activities

In this paper, particular conditions of retail trade SMEs was analyzed, identifying not enough financial resources for using powerful tools for solve vehicle routing problem (VRP). On the other hand, in literature revised could not be identified studies about application of current approaches for solving VRP in SMEs. Additionally because of high cost, commercial software do not fit investment budget of those companies. Through a simple insertion heuristic for VRP with split deliveries and time windows (SDVRPTW), developed on an accessible technology platform like Microsoft® Excel™, was validated that SDVRPTW is an appropriate approach for solving vehicle routing problem on retail trade SMEs. Computational results show that the heuristic proposed can reduce about 50% the fleet size

Emplazamiento de plataformas logísticas para el desarrollo armónico de la red intermodal en el país

This article considers the problem of locating multiple installations for the intermodal transport network in Colombia, and is based on the analysis of the transport of cargo from the main generating cities to the three most important port cities in the Caribbean region of the country: Barranquilla, Cartagena and Santa Marta; integrating the modes of transport by land, road and river. According to this, land transport by road is used from the source of cargo to the possible locations of the logistic platforms, and then the Magdalena River basin is used as a unique river corridor. The model proposed consists of determining the optimal location of a series of logistic platforms that guarantee a system of integration and cooperation in transport strategies for the country, in which aggregation and disaggregation of freight operations will be possible. In this aspect, an entire mixed programming model is performed with the objective of minimizing the total costs of transport and operation of the new intermodal network, with restrictions associated with the generation and processing of cargo, obtaining results in the cost functions related to cargo transport and leaving as evidence the potential of integrating intermodal transport for the country's competitiveness. Este artículo considera un problema de localización de instalaciones múltiples para la red de transporte intermodal en Colombia, para ello se analizó el transporte de carga desde las principales ciudades generadoras hasta las tres ciudades portuarias más importantes de la región caribe del país: Barranquilla, Cartagena y Santa Marta; integrando dos modos de transporte, terrestre por carretera y fluvial. De acuerdo a esto, el transporte terrestre por carretera se utiliza desde los orígenes de carga hasta las ubicaciones posibles de las plataformas logísticas, para luego usar como único corredor fluvial la cuenca del río Magdalena. El modelo propuesto consiste en determinar la ubicación óptima de una serie de plataformas logísticas que garantizan un sistema de integración y cooperación en estrategias de transporte para el país, en las cuales serán posibles operaciones de agregación y de desagregación de carga. En este aspecto, se realiza un modelo de programación mixto entero con el objetivo de minimizar los costos totales de transporte y operación de la nueva red intermodal, con restricciones asociadas a la generación y procesamiento de carga, obteniendo resultados en las funciones de costos referentes al transporte de carga y dejando como evidencia el potencial que tiene la integración del transporte intermodal para la competitividad del país.