22 research outputs found

    Inventory ordering policies for mixed sale of products under inspection policy, multiple prepayment, partial trade credit, payments linked to order quantity and full backordering

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    The situation where serviceable products are sold together with a proportion of deteriorating products to consumers is rarely discussed in the literature. This article proposes an inventory model with disparate inventory ordering policies under a situation where a portion of serviceable products and a portion of deteriorating products are sold together to consumers (i.e. mixed sales). The ordering policies consider a hybrid payment strategy with multiple prepayment and partial trade credit schemes linked to order quantity under situations where no inventory shortage is allowed and inventory shortage is allowed with full backorder. The hybrid payment policy offered by a supplier is introduced into the classical economic ordering quantity model to investigate the optimal inventory cycle and the fraction of demand that is filled from the deteriorating products under inspection policy. Further, a new solution method is proposed that identifies optimal annual total profit with mixed sales assuming no inventory shortage and inventory shortage with full backorder. The impact of an inspection policy is investigated on the optimality of the solution under hybrid payment strategies for the deteriorating products. The validation of the proposed model and its solution method is demonstrated through several numerical examples. The results indicate that the inventory model along with the solution method provide a powerful tool to the retail managers under real-world situations. Results demonstrate that it is essential for the managers to consider inclusion of an inspection policy in the mixed sales of products, as the inspection policy significantly increases the net annual profit

    Supply chain finance for ameliorating and deteriorating products: a systematic literature review

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    Ameliorating and deteriorating products, or, more generally, items that change value over time, present a high sensitiveness to the surrounding environment (e.g., temperature, humidity, and light intensity). For this reason, they should be properly stored along the supply chain to guarantee the desired quality to the consumers. Specifically, ameliorating items face an increase in value if there are stored for longer periods, which can lead to higher selling price. At the same time, the costumers’ demand is sensitive to the price (i.e., the higher the selling price the lower the final demand), sensitiveness that is related to the quality of the products (i.e., lower sensitiveness for high-quality products). On the contrary, deteriorating items lose quality and value over time which result in revenue losses due to lost sales or reduced selling price. Since these products need to be properly stored (i.e., usually in temperature- and humidity-controlled warehouses) the holding costs, which comprise also the energy costs, may be particularly relevant impacting on the economic, environmental, and social sustainability of the supply chain. Furthermore, due to the recent economic crisis, companies (especially, small and medium enterprises) face payment difficulties of customers and high volatility of resources prices. This increases the risk of insolvency and on the other hand the financing needs. In this context, supply chain finance emerged as a mean for efficiency by coordinating the financial flow and providing a set of financial schemes aiming at optimizing accounts payable and receivable along the supply chain. The aim of the present study is thus to investigate through a systematic literature review the two main themes presented (i.e., inventory management models for products that change value over time, and financial techniques and strategies to support companies in inventory management) to understand if any financial technique has been studied for supporting the management of this class of products and to verify the existing literature gap

    Modelos de Inventarios con Productos Perecederos: Revisión de la Literatura

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    This paper presents a review of the main characteristics of the mathematical modelsdeveloped by the scientific community in order to determine an optimal inventory policyfor deteriorating items. Thus, a classified bibliography of 390 articles published from2001 to 2014 in high-impact journals is submitted while considering the type of demandand deterioration, the integration of inventory and pricing decisions, the inclusionof shortage and/or the time value of money, the consideration of multiple items and/ormulti-echelon systems, and the incorporation of uncertain parameters other than demand.Finally, research questions not yet addressed by the research community in the field ofinventory control for deteriorating items are pointed out.En el presente artículo se lleva a cabo una revisión de las principales características estudiadas por la comunidad científica en el desarrollo de modelos matemáticos que buscan definir una política de inventario óptima para productos que se deterioran. De este modo, se referencian 390 artículos publicados a partir del año 2001 en revistas de gran impacto, teniendo en cuenta: el tipo de demanda y deterioro representado en los modelos matemáticos, el estudio de una política de precio óptima, la inclusión de faltantes y/o valor del dinero en el tiempo, el estudio de múltiples productos y/o dos o más eslabones de la cadena de suministro, y la utilización de parámetros o variables difusas. Finalmente, se identifican oportunidades de investigación que a la fecha no han sido abordadas por la comunidad científica en este campo del conocimiento

    Modelling and Determining Inventory Decisions for Improved Sustainability in Perishable Food Supply Chains

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    Since the introduction of sustainable development, industries have witnessed significant sustainability challenges. Literature shows that the food industry is concerned about its need for efficient and effective management practices in dealing with perishability and the requirements for conditioned storage and transport of food products that effect the environment. Hence, the environmental part of sustainability demonstrates its significance in this industrial sector. Despite this, there has been little research into environmentally sustainable inventory management of deteriorating items. This thesis presents mathematical modelling based research for production inventory systems in perishable food supply chains. In this study, multi-objective mixed-integer linear programming models are developed to determine economically and environmentally optimal production and inventory decisions for a two-echelon supply chain. The supply chain consists of single sourcing suppliers for raw materials and a producer who operates under a make-to-stock or make-to-order strategy. The demand facing the producer is non-stationary stochastic in nature and has requirements in terms of service level and the remaining shelf life of the marketed products. Using data from the literature, numerical examples are given in order to test and analyse these models. The computational experiments show that operational adjustments in cases where emission and cost parameters were not strongly correlated with supply chain collaboration (where suppliers and a producer operate under centralised control), emissions are effectively reduced without a significant increase in cost. The findings show that assigning a high disposal cost, limit or high weight of importance to perished goods leads to appropriate reduction of expected waste in the supply chain with no major cost increase. The research has made contributions to the literature on sustainable production and inventory management; providing formal models that can be used as an aid to understanding and as a tool for planning and improving sustainable production and inventory control in supply chains involving deteriorating items, in particular with perishable food supply chains.the Ministry of Science and Technology, the Royal Thai Government

    Advances in Optimization and Nonlinear Analysis

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    The present book focuses on that part of calculus of variations, optimization, nonlinear analysis and related applications which combines tools and methods from partial differential equations with geometrical techniques. More precisely, this work is devoted to nonlinear problems coming from different areas, with particular reference to those introducing new techniques capable of solving a wide range of problems. The book is a valuable guide for researchers, engineers and students in the field of mathematics, operations research, optimal control science, artificial intelligence, management science and economics

    Planificación de la logística en redes de salud: análisis y resolución

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    Healthcare networks bring together a wide range of public and private entities (hospitals, specific service units, healthcare professionals, …) at local or regional level that seek for management effectiveness, decisional efficacy and coordination. This thesis analyzes the problem statement: "How can those organizations integrate their internal logistic network?" Theories, concepts and integration guidelines from supply chain management theory have been applied to investigate this problem. On healthcare networks already in place, the application of centralized planning procedures is the more appropriate management strategy to rationalize and pilot the change processes. Hence, a general tactical level model is stated as a mixed integer linear programming (MILP) model supporting decisions on the global view of network layout and the coordinating policy among facilities in such networks. Apart from the adoption of optimization tools to provide a framework for costefficient operations, we have identified that information sharing and service level agreements are the key aspects in the effective accomplishment of logistics integration. We have conducted a case study at the Andalusian Regional Network of Clinical Laboratories (ANCL), a large healthcare network with geographically dispersed hospitals, clinics, and testing laboratories, that initiated an organizational strategy to enhance accessibility to services, quality of care and cost savings. Different solution strategies have been addressed in the MILP model that arises, in order to embed this model into a graphical, interactive and responsive Decision Support System (DSS) tool to support ANCL planners’ analysis of What-If scenarios. Drawing on the ANCL case study, it appears that the integration of the Information Tecnologies (IT) Systems at the different facilities and locations within the network and the centralization of the logistic planning procedure can be of invaluable help for aligning operational models and organizational behavior around demand, capacity and network configuration. This suggests that although such integration projects are difficult, costly and complex, they seem worth undertaking.Las Redes de Salud se basan en el trabajo en común de una variedad de entidades públicas y privadas (hospitales, unidades de servicios específicos, profesionales sanitarios,...) a nivel local o regional, en busca de una gestión efectiva, con toma de decisiones y coordinación eficientes. Esta tesis analiza la siguiente pregunta de investigación: "¿Cómo pueden las organizaciones integrar su red logística interna" Las teorías, conceptos y directrices de integración de la Cadena de Suministro se han aplicado para investigar este problema. En redes de salud ya funcionando, la aplicación de procedimientos de planificación centralizada se identifica como la estrategia de gestión más adecuada para racionalizar y pilotar los procesos de cambio. Por ello, planteamos abordar el objeto de la tesis mediante un modelo de programación lineal entera mixta (MILP) de nivel táctico, del que emanarán las decisiones sobre la visión global del diseño de la red y la política de coordinación entre los miembros de la red. Además de la adopción de herramientas de optimización para proporcionar un marco para operaciones eficientes en costes, hemos identificado como aspectos clave en la consecución efectiva de la integración logística en este tipo de redes el intercambio de información y el cumplimiento de acuerdos de nivel de servicio. Como caso práctico, hemos realizado esta integración en la Red Andaluza Regional de Laboratorios Clínicos (ANCL), una red sanitaria extensa con hospitales, clínicas y laboratorios clínicos dispersos geográficamente, que inició una estrategia de cambio organizacional para mejorar la accesibilidad al servicio de pruebas clínicas, la calidad del servicio y propiciar ahorro de costes. Sobre el MILP que resulta al abordar este caso de estudio, hemos aplicado diferentes estrategias de solución. Puesto que este modelo de optimización ha de usarse como el corazón de un Sistema de Soporte a la Decisión (DSS) a disposición de los planificadores ANCL para realizar análisis de escenarios, la agilidad en la generación de soluciones es un requisito primordial. Basándonos en nuestra experiencia con la ANCL, parece que tanto la integración de los sistemas de Tecnologías de Información de los diferentes miembros en la red como la centralización del procedimiento de planificación logística (a través del cual se fijan las directrices de coordinación anual) son de inestimable ayuda para la alineación del modelo operativo y el comportamiento organizacional en torno a demanda, capacidad y configuración de red. Esto sugiere que aunque tales proyectos de integración sean difíciles, costosos y complejos, el esfuerzo parece valer la pena
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