Descripción y análisis de los trabajos existentes sobre el efecto "bullwhip" y su tratamiento con técnicas de teoría de control

El presente trabajo recoge las aportaciones que se han hecho para estudiar y mitigar el efecto bullwhip, basadas en la aplicación de las técnicas de control lineal en modelos de la cadena de suministro. En el capítulo 2 se repasan los elementos relacionados con la gestión de la empresa, necesarios para entender y analizar el efecto bullwhip: la cadena de suministro, la gestión de la cadena se suministro, la política de inventarios y los sistemas de soporte a la decisión. En el capítulo 3 de describen los componentes que forman parte de un modelo de cadena de suministro, en el capítulo 4 se analiza la naturaleza, las causas y estrategias para reducir el efecto bullwhip, en el capítulo 5 se trata la aplicación de la teoría de control al estudio del efecto bullwhip. Finalmente el capítulo 6 reflejas las conclusiones y líneas de trabajo abiertas sobre el tema

Embodying decisions on work shifts into strategic manufacturing capacity planning

© 2018 Informa UK Limited, trading as Taylor & Francis Group In spite of the obvious impact that decisions on workforce planning have on the capacity of a production system, they are rarely mentioned in strategic capacity planning literature. This paper analyses the implications of embodying decisions on work shifts in strategic capacity planning and proposes a mathematical programming model that allows treating any type of relationship between the intensity in the use of the production equipment and maintenance and variable production costs. A computational experiment shows that the model can be solved in acceptable computing times for moderate values of the number of types of equipment and of work shifts. Using the model, the optimal solutions for diverse scenarios are presented and compared with those obtained under the assumption that the work shifts must be kept invariable over the entire horizon.Peer ReviewedPostprint (author's final draft

Assessing the impact on optimal production capacities in a closed-loop logistics system of the assumption that returns are stochastically independent of sales

Purpose: This paper is concerned with a reverse logistic system where returns are stochastically dependents on sales. The aim of the paper is to assess the influence on optimal production capacities when is assumed that returns are stochastically independent of sales. Design/methodology/approach: This paper presents a model of the system. An approximated model where is assumed that returns are stochastically independent of sales, is formulated to obtain the optimal capacities. The optimal costs of the original and the approximated models are compared in order to assess the influence of the assumption made on returns. Findings: The assumption that returns are stochastically independent of sales is significant in few cases. Research limitations/implications: The impact of the assumption on returns is assessed indirectly, by comparing the optimal costs of both models: the original and approximated. Practical implications: The problem of calculating the optimal capacities in the original model is hard to solve, however in the approximated model the problem is tractable. When the impact of the assumption that returns are stochastically independent of sales is not significant, the approximated model can be used to calculate the optimal capacities of the original model. Originality/value: Prior to this paper, few papers have addressed with the problem of calculating the optimal capacities of reverse logistics systems. The models found in these papers assumed that returns are stochastically independent of sales.Peer Reviewe

Minimizing rework costs in multistage production processes by modifying quality specification limits

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksMultistage production processes are becoming more important in the industry to ensure levels of flexibility, efficiency and modularity. Thus, the way in which companies define optimal production parameters related to production costs and quality must be adapted to this reality. In this paper we introduce a multi-response optimization (MRO) model for a two stage production process. The model gives first stage quality specification limits which minimize the rework costs caused by the nonconforming parts of the whole process. The proposed model is applied to an example based on a production process of the automotive industry. The benefits of the model are evaluated by comparing the capability and the rework costs of the multistage production process before and after the optimization.Peer ReviewedPostprint (published version

An evolutionary concept analysis of the supply chain response

Supply chain managers are challenged to respond quickly and efficiently to external and internal changes. A review conducted with regard to how the concept of supply chain response (SCR) is applied in suppliers’ and manufacturing processes, as well as in flexibility, agility, and resilience strategies, confirms that the concept is ambiguous and lacks pillars that guide complete application in any process of the supply chain. The purpose of this research is twofold. The first goal is to identify the attributes, antecedents, and consequences of an SCR. The second is to establish the pillars of a general definition of an SCR that is applicable to all situations in which a supply chain must respond. This study applied Rodgers' evolutionary approach to analyze the concept of SCR. Literature published in English between 1996 – 2020 dealing with SCR was used to apply the phases of Rodgers' evolutionary method. We identified the following four pillars: (1) the stimulus to which the supply chain responds, (2) the adaptation of supply chain activities, (3) the objectives that the supply chain intends to achieve with its response to the stimulus, and (4) the evaluation of the response to the stimulus. Based on these four pillars, we propose a general definition of SCR. This definition contributes to the groundwork for reaching a consensus on the concept of SCR.Postprint (published version

Supply chain response during the COVID-19 pandemic: a multiple-case study

This study explores the responses of manufacturing and service provision companies in Santiago de Cali to stimuli during the COVID-19 pandemic. The responses included changes in demand, absenteeism, and the development of new products, which affected the supply chain (SC). The qualitative methodology of the multiple-case study was used. The evidence for the multiple-case studies was collected through semi-structured interviews, where the interviewees were SC experts from four manufacturing companies and one service company. The data analysis was performed in two phases. In phase one, the case study protocol was completed, and in phase two, thematic analysis was used to identify supply chain response (SCR) patterns. The results revealed two aspects of the SCR. First, to respond to a stimulus, SC adapted activities other than those of suppliers and manufacturers, such as product design and development, human resources, budgeting, and logistics. Second, the SCs used several alternatives to respond to the stimuli. This study contributes to two aspects of the SCR literature: (1) it documents the identification, detection, planning, and evaluation of SCR in response to a stimulus, and (2) it proposes the concept of the response alternatives. The response alternatives concept facilitates decision-making and resource management in SCR.Peer ReviewedPostprint (published version

Evaluating urban freight transport policies within complex urban environments

Urban Freight Transport (UFT) entails significant advantages for the economic growth of cities, but can also hamper population quality of life, obstructing vehicles and people movements while exacerbating environmental problems. Many initiatives have been engaged by many city administrators in order to efficiently manage UFT, evaluating different policies at a global scale. From the perspective of operators, most works analyze a limited set of policies or only focus on the benefits of companies. In this work, a decisionmaking process is used to evaluate a large set of UFT policies, through different attributes representing the advantages and limitations of each policy over promoter companies and the society. To do so, an ex-ante procedure in five steps is proposed to classify the policies: (1) attributes definition, (2) attributes weighting, (3) policy-attribute assessment, (4) policy ranking, and (5) feasibility threshold satisfaction. The whole process is supported on consultations to 26 experts regarding shop supply and restocking activities within complex urban environments. Results show a classification of the analyzed policies, according to their suitability for implementation ; which could be extended (directly or with small adjustments) to other contexts, given the flexibility of the decision-making procedure developed.Peer ReviewedPostprint (author's final draft

Introducing Risk Considerations into the Supply Chain Network Design

Supply chains (SC) aim to provide products to the final customer at a certain service level. However, unforeseen events occur that impede supply chain objectives. SC Risk has been studied in the literature, providing frameworks and methodologies to manage SC failures. Nevertheless, more efforts are needed to prevent hazardous and disruptive risks and their consequences. These risks must be considered during the process of designing a supply chain. Somemethodological contributions concerning risk in the supply chain network design (SCND) are conceptual frameworks formitigating SC disruptions, which suggest strategies andmeasures for designing robust and resilient SCs. Although such contributions are valuable, they do not indicate how to cope with risk when designing a SC. The main objective of this research is to describe amethodology aimed at including risk considerations into the SCND. Our proposal aims to be, on the one hand, a comprehensive approach that includes a risk identification and assessment procedure in each of the stages of the SCND process and, on the other hand, a tool for decision-making in SC design or redesign processes when SC risks need to be considered. The methodology proposed is an extension of a SCND methodology including risk considerations in order to improve the performance of the supply chains. A case study illustrates how the proposed methodological works, achieving the identification of SC risks already observed in previous works.Peer ReviewedPostprint (published version

Introducing Risk Considerations into the Supply Chain Network Design

Supply chains (SC) aim to provide products to the final customer at a certain service level. However, unforeseen events occur that impede supply chain objectives. SC Risk has been studied in the literature, providing frameworks and methodologies to manage SC failures. Nevertheless, more efforts are needed to prevent hazardous and disruptive risks and their consequences. These risks must be considered during the process of designing a supply chain. Somemethodological contributions concerning risk in the supply chain network design (SCND) are conceptual frameworks formitigating SC disruptions, which suggest strategies andmeasures for designing robust and resilient SCs. Although such contributions are valuable, they do not indicate how to cope with risk when designing a SC. The main objective of this research is to describe amethodology aimed at including risk considerations into the SCND. Our proposal aims to be, on the one hand, a comprehensive approach that includes a risk identification and assessment procedure in each of the stages of the SCND process and, on the other hand, a tool for decision-making in SC design or redesign processes when SC risks need to be considered. The methodology proposed is an extension of a SCND methodology including risk considerations in order to improve the performance of the supply chains. A case study illustrates how the proposed methodological works, achieving the identification of SC risks already observed in previous works.Peer ReviewedPostprint (published version

Cálculo de la capacidad de fabricación y refabricación óptima para sistemas con logística inversa y demanda determinista constante

La opción de disponer de logística inversa en un sistema de producción es una oportunidad para mejorar los costes, sin embargo también signifi ca introducir una fuente de incertidumbre en su comportamiento. En este estudio se establece un algoritmo para el cálculo de las capacidades óptimas de fabricación y refabricación en un sistema con logística inversa y demanda constante teniendo en cuenta el comportamiento aleatorio de la cantidad y el ritmo de productos retornados. También se muestra un ejemplo en el que se obtiene las capacidades óptimas.Postprint (published version