scholarly journals A multi-period and multi-product optimizer for cooperative supply chains

2012 ◽  
Vol 43 (1) ◽  
pp. 77-92 ◽  
Author(s):  
M. Sepehri ◽  
K. Fayazbakhsh

Members in a traditional supply chain compete to reduce their individual costs. But total cost is minimized in a cooperative, or a corporate managed, supply chain. A lower average cost and a lower cost variation are achieved by cooperative individual members in the long-run. The problem is formulated and solved as an integrated flow network. Previous research is expanded to include multi-period and multi-product cooperative supply chain with possibility of holding inventory in a multi-stage, multi-member setup. A Cooperative Supply Optimizer System (CSOS), a software-based coordination mechanism, is developed for large chains. It gathers operational information from members of the supply chain, and then guides them on ordering decisions for a minimum cost of the entire supply chain. Simulation results indicate an approximately 26% reduction in total supply chain costs, utilizing this formulation over a competitive setup. As the holding costs increase, the problem decomposes into single period (Just-in-time) again. The disturbing bullwhip effect disappears in cooperative supply chains.

2019 ◽  
Vol 14 (2) ◽  
pp. 360-384 ◽  
Author(s):  
Maria Drakaki ◽  
Panagiotis Tzionas

PurposeInformation distortion results in demand variance amplification in upstream supply chain members, known as the bullwhip effect, and inventory inaccuracy in the inventory records. As inventory inaccuracy contributes to the bullwhip effect, the purpose of this paper is to investigate the impact of inventory inaccuracy on the bullwhip effect in radio-frequency identification (RFID)-enabled supply chains and, in this context, to evaluate supply chain performance because of the RFID technology.Design/methodology/approachA simulation modeling method based on hierarchical timed colored petri nets is presented to model inventory management in multi-stage serial supply chains subject to inventory inaccuracy for various traditional and information sharing configurations in the presence and absence of RFID. Validation of the method is done by comparing results obtained for the bullwhip effect with published literature results.FindingsThe bullwhip effect is increased in RFID-enabled multi-stage serial supply chains subject to inventory inaccuracy. The information sharing supply chain is more sensitive to the impact of inventory inaccuracy.Research limitations/implicationsInformation sharing involves collaboration in market demand and inventory inaccuracy, whereas RFID is implemented by all echelons. To obtain the full benefits of RFID adoption and collaboration, different collaboration strategies should be investigated.Originality/valueColored petri nets simulation modeling of the inventory management process is a novel approach to study supply chain dynamics. In the context of inventory errors, information on RFID impact on the dynamic behavior of multi-stage serial supply chains is provided.


SIMULATION ◽  
2020 ◽  
Vol 96 (9) ◽  
pp. 767-778 ◽  
Author(s):  
Ahmed Shaban ◽  
Francesco Costantino ◽  
Giulio Di Gravio ◽  
Massimo Tronci

Numerous studies have confirmed the negative impact of the lack of coordination on supply chain performance. In particular, the lack of coordination leads to the bullwhip effect, which has severe impacts on supply chain stability. This paper evaluates a proposed coordination mechanism that allows a decentralized information sharing in multi-echelon supply chains. The proposed mechanism “Info-Smooth” utilizes the ordering rule of the generalized (R, S) policy in which a replenishment order can be transferred to upstream echelons including two pieces of information (demand forecast and inventory balance). As the generalized (R, S) can allow order smoothing, Info-Smooth combines the power of both information sharing and order smoothing. A simulation modeling methodology is employed to investigate the effectiveness of Info-Smooth in a multi-echelon supply chain. The factorial design results have shown that Info-Smooth is successful in mitigating the bullwhip effect whilst keeping acceptable inventory stability, compared to the traditional supply chain model.


2020 ◽  
Author(s):  
Zhan Qu ◽  
Horst Raff

This paper shows that decentralized supply chains, in which upstream firms use linear wholesale prices, may experience lower upstream production and downstream sales volatility than vertically integrated supply chains and may be less susceptible to the bullwhip effect by which the variance of upstream production exceeds the variance of downstream sales. The reason is that decentralized supply chains exhibit a price effect, whereby upstream producers raise wholesale prices in the case of positive demand shocks and lower wholesale prices in the case of negative demand shocks. Whereas upstream producers benefit from the price effect and, thus, from a dampening of the bullwhip effect, downstream firms may lose, and overall supply chain profit may decrease. This paper was accepted by Vishal Gaur, operations management.


Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Junhai Ma ◽  
Wandong Lou

This paper studies the complex characteristics caused by the price competition in multichannel household appliance supply chains. We consider a two-level household appliance supply chain system consisting of a manufacturer with an Internet channel and a retailer with a traditional channel and an Internet channel. Each channel’s price-setting follows the bounded rational decision process in order to obtain the optimal profit or more market share. Considering that the price competition often leads to the demand and order fluctuation, we also investigate the bullwhip effect of the multichannel supply chains on the basis of the order-up-to-inventory policy. From the numerical simulation, we find a system in a chaotic state will suffer larger bullwhip effect than a stable system, and the manufacturer’s Internet channel is helpful to mitigate the bullwhip effect. Our results provide some useful managerial inspirations for the household manufacturer and retailers. Firstly, each channel should make their retail price with a suitable price adjustment speed in the stable region, and each time pricing cannot exceed the domain of attraction. Secondly, the manufacturer can adopt a more radical pricing strategy in their Internet channel to mitigate the bullwhip effect. Thirdly, the price adjustment should be reviewed and be appropriately reduced if the price adjustment is too large.


Author(s):  
R. Dhanalakshmi ◽  
P. Parthiban ◽  
K. Ganesh ◽  
T. Arunkumar

In many multi-stage manufacturing supply chains, transportation related costs are a significant portion of final product costs. It is often crucial for successful decision making approaches in multi-stage manufacturing supply chains to explicitly account for non-linear transportation costs. In this article, we have explored this problem by considering a Two-Stage Production-Transportation (TSPT). A two-stage supply chain that faces a deterministic stream of external demands for a single product is considered. A finite supply of raw materials, and finite production at stage one has been assumed. Items are manufactured at stage one and transported to stage two, where the storage capacity of the warehouses is limited. Packaging is completed at stage two (that is, value is added to each item, but no new items are created), and the finished goods inventories are stored which is used to meet the final demand of customers. During each period, the optimized production levels in stage one, as well as transportation levels between stage one and stage two and routing structure from the production plant to warehouses and then to customers, must be determined. The authors consider “different cost structures,” for both manufacturing and transportation. This TSPT model with capacity constraint at both stages is optimized using Genetic Algorithms (GA) and the results obtained are compared with the results of other optimization techniques of complete enumeration, LINDO, and CPLEX.


2020 ◽  
Vol 40 (10) ◽  
pp. 1649-1660 ◽  
Author(s):  
Robert B. Handfield ◽  
Gary Graham ◽  
Laird Burns

PurposeUsing the constructal law of physics this study aims to provide guidance to future scholarship on global supply chain management. Further, through two case studies the authors are developing, the authors report interview findings with two senior VPs from two multi-national corporations being disrupted by COVID-19. This study suggests how this and recent events will impact on the design of future global supply chains.Design/methodology/approachThe authors apply the constructal law to explain the recent disruptions to the global supply chain orthodoxy. Two interviews are presented from case studies the authors are developing in the USA and UK – one a multi-national automobile parts supplier and the other is a earth-moving equipment manufacture. Specifically, this is an exploratory pathway work trying to make sense of the COVID-19 pandemic and its impact on supply chain scholarship.FindingsAdopting the approach of Bejan, the authors believe that what is happening today with COVID-19 and other trade disruptions such as Brexit and the USA imposing tariffs is creating new obstacles that will redirect the future flow of supply chains.Research limitations/implicationsIt is clear that the COVID-19 response introduced a bullwhip effect in the manufacturing sector on a scale never-before seen. For scholars, the authors would suggest there are four pathway topics going forward. These topics include: the future state of global sourcing, the unique nature of a combined “demand” and “supply shortage” bullwhip effect, the resurrection of lean and local production systems and the development of risk-recovery contingency strategies to deal with pandemics.Practical implicationsSupply chain managers tend to be iterative and focused on making small and subtle changes to their current system and way of thinking, very often seeking to optimize cost or negotiate better contracts with suppliers. In the current environment, however, such activities have proved to be of little consequence compared to the massive forces of economic disruption of the past three years. Organizations that have more tightly compressed supply chains are enjoying a significant benefit during the COVID-19 crisis and are no longer being held hostage to governments of another country.Social implicationsAn implicit assumption in the press is that COVID-19 caught everyone by surprise, and that executives foolishly ignored the risks of outsourcing to China and are now paying the price. However, noted scholars and epidemiologists have been warning of the threats of pandemics since the severe acute respiratory syndrome (SARS) virus. The pundits would further posit that in their pursuit of low-cost production, global corporations made naive assumptions that nothing could disrupt them. Both the firms the authors have interviewed had to close plants to protect their workforce. It was indicated in the cases the authors are developing that it is going to take manufacturers on average one month to recover from 4–6 days of disruption. These companies employ many thousands of people, and direct and ancillary workers are now temporarily laid off and face an uncertain future as/when they will recover back to normal production.Originality/valueUsing the constructal law of physics, the authors seek to provide guidance to future scholarship on global supply chain management. Further, through two case studies, the authors provide the first insight from two senior VPs from two leading multi-national corporations in their respective sectors being disrupted by COVID-19. This study is the first indication to how this and recent disruptive events will impact on the design of future global supply chains. Unlike the generic work, which has recently appeared in HBR and Forbes, it is grounded in real operational insight.


2019 ◽  
Vol 6 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Prabhat Mittal

The present study is an attempt to quantify the Bullwhip Effect (BWE) -the phenomenon in which information on demand is distorted in moving up a supply chain. Assuming that the retailer employs an order-up-to level policy with auto-regressive process (AR), the paper investigates the influence of forecasting methods on bullwhip effect. Determining the order-up-to levels and the orders for the retailers’ demands in an isolated manner neglects the correlation of the demands and the relevant risk pooling effects associated with the network structure of the supply chains are disregarded. It is illustrated that the bullwhip effects are significantly reduced with consideration of potential correlation between the retailers’ demand.


2021 ◽  
Vol 6 (1) ◽  
pp. 63-74
Author(s):  
Davor Dujak ◽  
◽  
Dario Šebalj ◽  
Karolina Kolinska

Natural gas is third most used fossil fuel and energy resource in the world, with significant increase in its consumption over last 20 years. As a consequence, research in optimisation of its supply chain processes are becoming increasingly significant. This paper aims to develop conceptual framework for material and information flow optimisation in natural gas supply chain and suggests its future use. Based on previous researches on mapping natural gas supply chain, bullwhip effect in natural gas supply chain and simulation models in natural gas supply chain, paper proposes new conceptual framework for material and information flow optimisation in natural gas supply chain. Results of implementation of this framework in natural gas supply chain of Republic of Croatia are presented with all suggestions for improvement explained. Keywords: natural gas supply chain, simulation model, bullwhip effect


2021 ◽  
Vol 13 (2) ◽  
pp. 813 ◽  
Author(s):  
Wensheng Yang ◽  
Yinyuan Si ◽  
Jinxing Zhang ◽  
Sen Liu ◽  
Andrea Appolloni

In response to the online channels established by manufacturers, physical retailers are starting to offer innovative services, which will intensify conflicts between manufacturers and retailers. Considering that the conflict will affect the operation efficiency and sustainable development of the supply chain, the coordination mechanism of a dual-channel supply chain has been established. In this study, we construct the Stackelberg game model based on consumer utility theory to analyze the complex mechanism of retailers’ innovation input level affecting supply chain operation and design the double coordination mechanism. The results show that: (1) an optimal combination of wholesale prices, retail prices and innovation input levels can optimize the operational efficiency of the supply chain, (2) Noncooperation among channel members affects the retailer’s product pricing, decreases the market share of the physical channel and increases the market demand of manufacturers, (3) The dual coordination mechanism can alleviate channel conflicts, which can improve the operational efficiency of the supply chain. This study provides several insights on the theory of organizational coordination and sustainable development in conflicts of dual-channel supply chains.


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