Impact of reverse logistics on supply chain performance

Purpose – The purpose of this paper is to analyse the impact of reverse logistics on order and inventory variance amplification in a single-echelon supply chain (SC) and to propose a new order policy for dampening such amplification. Design/methodology/approach – A general review of the literature on sustainable operations and on the impact of reverse logistics on SC performance provides the foundation for the study. The authors use difference equation math approach for modelling and analysing a closed SC. A proper design of experiment and data collected from the European Union statistics validate the obtained numerical results. Findings – The variability of reverse flow in a closed loop S…

Closed-loop supply chains: What reverse logistics factors influence performance?

This paper analyses the inventory and order flow dynamics in closed-loop supply chains (CLSCs). In this kind of supply chains the reverse flow of materials entering the system for recycling purposes complicates the way in which inventories should be managed and replenishment policies should be designed. Specifically, we analyse the relationships between some reverse logistics’ factors (remanufacturing lead-time, return rate of recycled products, reverse order policy, and number of supply chain tiers) on the order and inventory variance amplification. We firstly perform a systematic literature review of the related studies. Secondly, by adopting a difference equation math approach and design…

MODELADO DE UNA PLATAFORMA DE E-MANTENIMIENTO, CMMS Y CBM

The information and communications technologies (ICT) are increasingly used in society and business. ICT have become a key element for business development and the improvement of activities in all departments. Analogously, the rise of Computerized Maintenance Management Systems (CMMS), Condition Based Maintenance (CBM), and the use of remote devices and functions such as e-maintenance, have opened great possibilities for maintenance optimization. Those techniques have resulted in the emergence of technological challenges such as interoperability between different systems in order to exchange and coordinate information. In this context, the application of business process modelling is a cruc…

Insights on Partial Information Sharing in Supply Chain dynamics

This paper provides an assessment of partial Information Sharing (IS) in Supply Chain (SC). We study the dynamics of collaborative multi-echelon structure, characterized by an increasing level of information visibility among partners. To do so, we mathematically model six four-echelon serial SCs via difference equations and conduct numerical simulations on the basis of a robust design of experiment. Results shows how (1) as the extent of IS increases, the performance of whole SC improves as well, and (2) the impact of IS depends not on which particular members are involved but on the number of collaborative members.

Mixed e-assessment: An application of the studentgenerated question technique

This paper presents the experiment of a mixed summative-formative evaluation in an asynchronous distance higher education context. In the experiment, performed in the distance course of Total Quality Management, Industrial Engineering, University of Guadalajara (Mexico), students are guided to formultate questions on specific topics. Studentgenerated questions are evaluated through an ad-hoc quantitative tool, specifically designed for the purpose: the four-criterion Observation Matrix. The experiment shows: (1) that it is possible to improve the Higher Education evaluation process and formalise students' skill in a more thoroughly way than with traditional evaluation; (2) how the student-e…

Supply chain modelling and analysis: an application of Latin square to a repeated coupling of non-linear differential equations

In the last 50 years, Forrester’s system dynamics techniques have been adopted to analyse problems and find solutions for global supply chains. An important topic in production-inventory system modelling is the design of experiment. The aim of this paper is to present an application of a statistical technique of design of experiment, the Latin Square Design, to set a combination of input values for the initial-value problem of non-linear repeated coupling of first-order differential equations modelling a production-inventory system. This design permits to reduce the number of experiments while allowing statistical analysis for testing the significance of the studied parameters.

Current economic downturn and supply chain: The significance of demand and inventory smoothing

The aim of this article is to analyse and quantify the effects of demand and inventory smoothing into supply-chain performance, facing the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so, we model a traditional serial three-stage supply chain and we test five settings of order smoothing under two shocks in the market demand, and we measure effects in terms of internal process benefits and customer service level of all supply chain partners. Results show that the implementation of this inventory strategy should be based on reward schemes; in fact a higher level of smoothing can generally improve the performance of the upstream st…

Methodological Approach to Studying the dynamics of production networks: a Discrete Event Simulation Model

This paper shows how discrete-event simulation represents an appropriate tool for approaching the dynamics of production networks. Three important factors influencing production network dynamics, specifically finite production capacity, manufacturing lead time, and its variability are discussed and a basic discrete-event simulation model is presented. Such model, which in its basic form represents a simple retail/distribution two-stage supply chain, is then extended in order to take into account those factors that can not be included in a classical control theoretical model.

Up-to-Date Supply Chain Management: The Coordinated (S, R) Order-Up-to

This paper presents the mathematical derivation of a new generation of the most largely used periodic review policy in supply chain: the coordinated (S, R) replenishment rule. We first derive the classical order-up-to model and then we modify it to generate the coordinated decision policy equations. We run a numerical simulation on a serial supply chain model to show differences in the two policies. We conclude on the managerial implications related to coordinated replenishment.

Inventory policies and information sharing in multi-echelon supply chains

The aim of this article is to show how to modify a replenishment rule in relation to the operational information shared by suppliers. More specifically, we present a model of an Automatic Pipeline Variable Inventory and Order-Based Production Control System rule for a multi-echelon supply chain characterised by different increasing levels of shared information. A numerical study is presented to underline the performance differences for three variants of the smoothing order rule in terms of bullwhip reduction, inventory stability and operational and customer responsiveness. Results show how the effectiveness of a smoothing replenishment rule depends on the level of information sharing.

The effect of inventory record inaccuracy in information exchange supply chains

Abstract The goal of this paper is to quantify the impact of Inventory Record Inaccuracy on the dynamics of collaborative supply chains, both in terms of operational performance (i.e. order and inventory stability), and customer service level. To do so, we model an Information Exchange Supply Chain under shrinkage errors in the inventory item recording activity of their nodes, present the mathematical formulation of such supply chain model, and conduct a numerical simulation assuming different levels of errors. Results clearly show that Inventory Record Inaccuracy strongly compromises supply chain stability, particularly when moving upwards in the supply chain. Important managerial insights…

Demand Sharing Inaccuracies in Supply Chains: A Simulation Study

We investigate two main sources of information inaccuracies (i.e., errors and delays) in demand information sharing along the supply chain (SC). Firstly, we perform a systematic literature review on inaccuracy in demand information sharing and its impact on supply chain dynamics. Secondly, we model several SC settings using system dynamics and assess the impact of such information inaccuracies on SC performance. More specifically, we study the impact of four factors (i.e., demand error, demand delay, demand variability, and average lead times) using three SC dynamic performance indicators (i.e., bullwhip effect, inventory variability, and average inventory). The results suggest that demand …

Avoiding Demand Amplification Phenomenon via Hi-tech Application: A What-If Supply Chain Analysis

The well-known deleterious effect of the amplification of variance of order rates in multi-echelon systems, commonly known as demand amplification phenomenon or bullwhip effect, still presents new challenges and continues to fascinate the operations management community. Recently this research field is focusing on the study of robustness of bullwhip avoidance techniques under uncertainty, as environmental conditions often determine variations in processes, with regards to production and delivery lead time, and variations in the parameters of the decision policies. This work aims at quantifying the efficacy of bullwhip dampening techniques and at verifying this efficacy against variations in…

On the Bullwhip Avoidance Phase: The Synchronised Supply Chain

Abstract The aim of this paper is to analyse the operational response of a Synchronised Supply Chain (SSC). To do so, first a new mathematical model of a SSC is presented. An exhaustive Latin Square design of experiments is adopted in order to perform a boundary variation analysis of the main three parameters of the periodic review smoothing ( S ,  R ) order-up-to policy: i.e., lead time, demand smoothing forecasting factor, and proportional controller of the replenishment rule. The model is then evaluated under a variety of performance measures based on internal process benefits and customer benefits. The main results of the analysis are: (I) SSC responds to violent changes in demand by re…

Production networks dynamics: analytical or non-analytical modelling?

Inventory record inaccuracy in supply chains: the role of workers' behavior

Purpose – The purpose of this paper is to explore the effect of inventory record inaccuracy due to behavioral aspects of workers on the order and inventory variance amplification. Design/methodology/approach – The authors adopt a continuous-time analytical approach to describe the effect of inbound throughput on the inventory and order variance amplification due to the workload pressure and arousal of workers. The model is numerically solved through simulation and results are analyzed with statistical general linear model. Findings – Inventory management policies that usually dampen variance amplification are not effective when inaccuracy is generated due to workers’ behavioral aspects. Sp…

Partial/Asymmetrical Information sharing in Supply Chain: A bibliometric analysis

The importance of Information Sharing (IS) between an enterprise and its customers or cooperating companies has been long recognized in Supply Chain (SC) research literature. In this paper we perform an exploratory analysis of the current state-of-art and challenges in the field of partial/asymmetrical IS in SC. To fulfil our objective we carry out a bibliometric analysis by adopting BibExcel and Gephi tools. We identify 115 articles and generate several co-citation maps. Our results show that the concepts of partial and asymmetrical IS in SCs are not well defined in literature.

Efecto Bullwhip y restricciones de capacidad productiva en las cadenas colaborativas

El objetivo del presente artículo es profundizar en el análisis de Evans y Naim (1) sobre la relación entre la capacidad de limitada producción y el efecto bullwhip, y actualizarlo en función de las recientes configuraciones de cadenas de suministro colaborativas. Se analizan tres cadenas de suministro con capacidad de producción limitada: la misma cadena de suministro tradicional estudiada por Evans y Naim (1), una cadena EPOS (Exchange Point of Sales) y una cadena sincronizada. Se adopta un sistema de métricas para evaluar los beneficios de los nodos de la cadena medidos en términos de estabilidad de la orden de pedido, estabilidad de los inventarios, y robustez del sistema, y en términos…

Modelling the Bullwhip Effect Dampening Practices in a Limited Capacity Production Network

This work infers on the conjoint adoption of collaboration practices and replenishment rules as bullwhip dampening techniques in a limited capacity production network. Continuous time differential equation methodology is adopted to model three supply chain configurations. Results show that theconditio sine qua non for long-term capacity strategy is the management and control of information asynchronies, provided by collaboration practices and ad-hoc decision policies. Furthermore the study reveals the phenomenon of bullwhip rough dampening.

On the Bullwhip Avoidance Phase: supply chain collaboration and order smoothing

This paper provides an assessment of the impact of collaboration and smoothing replenishment rules on supply chain operational performance and customer service level. Three supply chain configurations (i.e. Traditional, Information Exchange and Synchronised) in which orders are generated by smoothing (S, R) inventory control policies are studied for different proportional controllers. A supply chain stress test is performed through a sudden and intense change in demand. A structured and extended supply chain assessment framework is adopted. The main conclusions of this paper are the following. (i) The impact of Supply Chain Collaboration on overall supply chain performance is greater than t…

Capacity constrained supply chains: a simulation study

This paper explores the relationship between constrained capacity and supply chain performance. Six capacity constraint levels are studied under different inventory policies and information sharing strategies. The results suggest that an increment of production capacity, used in industry as local approach to manage increasing incoming orders, does not necessarily imply an improvement in customer service. In presence of information distortions, the strategy of augmenting production capacity can lead to satisfy at a higher cost an over-estimated market demand. The collaborative practices provide bullwhip effect dampening and inventory stability, and increase the ability of the structure to av…

An IT-enabled supply chain model: dynamic databases for network decision policy

Production Inventory and Enterprise System Implementation: An Ex-ante No-Cost Based Evaluation

The objective of this paper is to present an Enterprise System (ES) ex-ante no-cost based three step evaluation technique, which enables a pre-emptive analysis of the effects of an ES implementation using a system of referenced non financial performance metrics. The innovativeness is in the use of a simulation model fully integrated with the evaluation procedure. Researchers can extend the presented technique to further modelling approaches and test it on different market sectors. The analysis provides practitioners with a measurement system that enables an analysis of the effects of a given ES implementation and can be further employed in financial evaluations.

E-maintenance platform: a business process modelling approach

Las tecnologías de la información y la comunicación (TIC) se utilizan cada vez más en la sociedad y en los negocios. Las TIC se han convertido en un elemento clave para el desarrollo empresarial y la mejora de las actividades en todos los departamentos de una organización. Análogamente, la creciente importancia de los Sistemas de Gestión de Mantenimiento asistido por Ordenador (CMMS), Mantenimiento Basado en la Condición (CBM), y la aplicación de dispositivos remotos y funciones como el e-mantenimiento, han abierto grandes posibilidades para la optimización del mantenimiento. Estas técnicas han dado lugar a la aparición de retos tecnológicos, tales como la interoperabilidad entre diferentes…

A Simulation Model of a Tandem Coordinated Supply Chain

This paper presents a study of a coordinated production inventory-system. In the proposed model, any echelon considers its successors as part of its inventory system and generates the replenishment order on the basis of operational information of its partners. We show that the coordinated decision making allows elimination of information distortion along the chain. Furthermore, we show how the bottom-up transmission of inefficiencies, typical of traditional supply chains, is avoided.