Exploring the bullwhip effect by means of spreadsheet simulation.

An important supply chain research problem is the bullwhip effect: demand fluctuations increase as one moves up the supply chain from retailer to manufacturer. It has been recognized that demand forecasting and ordering policies are two of the key causes of the bullwhip effect. In this paper we present a spreadsheet application, which explores a series of replenishment policies and forecasting techniques under different demand patterns. It illustrates how tuning the parameters of the replenishment policy induces or reduces the bullwhip effect. Moreover, we demonstrate how bullwhip reduction (order variability dampening) may have an adverse impact on inventory holdings. Indeed, order smoothing may increase inventory fluctuations resulting in poorer customer service. As such, the spreadsheets can be used as an educational tool to gain a clear insight into the use or abuse of inventory control policies and improper forecasting in relation to the bullwhip effect and customer service. Keywords: Bullwhip effect, forecasting techniques, replenishment rules, inventory fluctuations, spreadsheet simulationBullwhip; Bullwhip effect; Forecasting techniques; Inventory fluctuations; Replenishment rule; Simulation; Spreadsheet simulation;

A Study of the Impact of Information Blackouts on the Bullwhip Effect of a Supply Chain Using Discrete-Event Simulations

This study adds to the supply chain management literature by introducing and investigating information blackouts, sudden and short-duration failure of the information flow. This study aims to contribute to the literature in following ways: first, to define information blackouts in a supply chain. Second, to investigate the response of supply chains to information blackouts using discrete-event simulation. Prior research has focused more on analyzing systemic disruptions to supply chains from well-known sources. We expect the results of this study to be useful to supply chain managers in disaster prone areas

Endüstri mühendisliğinde bilgisayar destekli öğrenme uygulaması

Text in English ; Abstract: English and TurkishIncludes bibliographical references (leaves 63-66)xi, 96 leavesLearning is the most central process in education where it's essential outcome being the assimilation of new skills, abilities, perspectives, attitudes, and knowledge. Learning is a life-long quest that is vital in today's information based economy. Educational institutions, though not exclusively, play a significant role in an individual's learning journey. Over the last two decades there has been significant research and development in methods of learning and teaching mostly spearheaded by institutions of higher education. At the core of these R&D efforts lie the need for improving the effectiveness of traditional methods of learning and teaching. Motivated by this need we designed and report here a computer aided learning application that helps better teach and learn some of the topics in inventory control and production planning in the discipline of industrial engineering. Computer aided learning environment provides time and location flexibility, enables asynchronicity, self-pacing, and experiential self-learning, extensively utilizes multi-media, and supports multiple types of learning styles. We designed our application in order to take advantage of all the benefits of this environment to reinforce the learning goals associated with our application area. Our application is a learning tool named WashMac Game. The game has three levels that are aligned with the progress of the student. Each level aims to simulate the production and sales process and teaching to calculate the product amounts. There are animations for teaching and understanding more easily and accurate.Öğrenme kelimesi, bilgi edinmek, yetenek ve beceri kazanmak anlamlarına gelmektedir. Öğrenme işi sonucunda yeni yetenekler, davranışlar kazanılır ve bilgi öğrenimi gerçekleşmektedir. Eğitim kurumlarının bilgiye ek olarak kişisel öğrenme üzerinde de etkin bir rolü vardır. Son 20 yılda öğrenme ile ilgili önemli araştırmalar ve gelişimler yaşanmıştır. Klasik öğrenme olarak ifade edilen öğrenme çeşidinde araştırma geliştirmeler sonucunda ilerlediğini ve yerini elektronik öğrenmeye bırakmaya başladığını görüyoruz. Bu araştırmalara istinaden endüstri mühendisliği için bilgisayar destekli öğrenme üzerine bir çalışma yaptık. Envanter kontrolü ve üretim planlama konularını kapsayan bir tasarım hazırladık. Bilgisayar destekli eğitim sayesinde, kullanıcılar zaman ve yer konularında esneklik kazanılabilmektedir. Bir diğer faydası ise kullanıcılar başka bir insana, öğretmene ayrıca ihtiyaç duymadan öğrenim görebilmektedir. Tasarladığımız uygulamanın ismi WashMac Game olup toplamda 3 seviyeden oluşmaktadır. Basitten başlayarak üretim ve satış süreçlerinde üretilecek miktarları hesaplamayı, envanteri takip etmeyi öğretmeyi hedefliyoruz. Öğrenme stillerini baz alarak animasyonlar kullandık. Kullanıcının dikkati çekebilen bir oyun olmasına dikkat ederek tasarımı hazırladık.IntroductionMotivationContributionsOutlineLearning TheoryTypes of IntelligenceTypes of LearningBloom’s TaxonomyBloom's Revised TaxonomyLearning StylesTradional LearningE-LearningProject Based LearningComputer Aided LearningLearning by DoingNew LearningOnline Learning CommunitiesLearning Objectives and Learning OutcomesY & Z GenerationIndustrial EngineersLiterature ReviewVisual Matrix Calculator for Undergraduate StudentsGeogebraThe Virtual CompanySupply Chain SimulatorThe Poker Chip GameImplementationsBeer GamePrisoner’s DilemmaTaxonomiesTaxonomy of Inventory Control PoliciesTaxonomy of Production ModesTaxonomy of Facility Layout TypesTaxonomy of Mathematical ModelsWashMac Learning GameWelcome ScreenFirst Level (Easy)TermsThe Second Level (Medium)EOQ Model(r,Q), (s,S) policiesThe Third Level (Hard)QuizzesAssembly LineConclusio

Destocking, the bullwhip effect, and the credit crisis : empirical modeling of supply chain dynamics

In this paper we analyze the strong sales dip observed in the manufacturing industry at the end of 2008, following the bankruptcy of Lehman Brothers and the subsequent collapse of the financial world. We suggest that firms’ desire to retain liquidity during these times prompted a reaction characterized by the reduction of working capital, which materialized as a synchronized reduction in target inventory levels across industries. We hypothesize that such a reaction effectively acted as an endogenous shock to supply chains, ultimately resulting in the demand dynamics observed. To test this proposition we develop a system dynamics model that explicitly takes into account structural, operational, and behavioral parameters of supply chains aggregated at an echelon level. We calibrate the model for use in 4 different business units of a major chemical company in the Netherlands, all situated 4 to 5 levels upstream from consumer demands in their respective supply chains. We show that the model gives both a very good historical fit and a prediction of the sales developments during the period following the Lehman collapse. We test the model’s robustness to behavioral parameter estimation errors through sensitivity analysis, and provide a comparison with experimental studies based on the ‘beer game’. We observe that the empirical data is aligned with experimental observations regarding the underestimation of the supply pipeline

Evaluating strategies for implementing industry 4.0: a hybrid expert oriented approach of B.W.M. and interval valued intuitionistic fuzzy T.O.D.I.M.

open access articleDeveloping and accepting industry 4.0 influences the industry structure and customer willingness. To a successful transition to industry 4.0, implementation strategies should be selected with a systematic and comprehensive view to responding to the changes flexibly. This research aims to identify and prioritise the strategies for implementing industry 4.0. For this purpose, at first, evaluation attributes of strategies and also strategies to put industry 4.0 in practice are recognised. Then, the attributes are weighted to the experts’ opinion by using the Best Worst Method (BWM). Subsequently, the strategies for implementing industry 4.0 in Fara-Sanat Company, as a case study, have been ranked based on the Interval Valued Intuitionistic Fuzzy (IVIF) of the TODIM method. The results indicated that the attributes of ‘Technology’, ‘Quality’, and ‘Operation’ have respectively the highest importance. Furthermore, the strategies for “new business models development’, ‘Improving information systems’ and ‘Human resource management’ received a higher rank. Eventually, some research and executive recommendations are provided. Having strategies for implementing industry 4.0 is a very important solution. Accordingly, multi-criteria decision-making (MCDM) methods are a useful tool for adopting and selecting appropriate strategies. In this research, a novel and hybrid combination of BWM-TODIM is presented under IVIF information

The bullwhip effect: Progress, trends and directions

This is the final version. Available on open access from Elsevier via the DOI in this recordThe bullwhip effect refers to the phenomenon where order variability increases as the orders move upstream in the supply chain. This paper provides a review of the bullwhip literature which adopts empirical, experimental and analytical methodologies. Early econometric evidence of bullwhip is highlighted. Findings from empirical and experimental research are compared with analytical and simulation results. Assumptions and approximations for modelling the bullwhip effect in terms of demand, forecast, delay, replenishment policy, and coordination strategy are considered. We identify recent research trends and future research directions concerned with supply chain structure, product type, price, competition and sustainability

Impacts of digital technologies on supply chain performance: a system dynamics approach

The advent of Industry 4.0 and associated digital technologies makes it possible to share information and access data real-time. Such a capability needs to be investigated in the Supply Chain Management (SCM) to study the joint impacts of digital technologies on transforming SC members’ behavior. In this paper, Cloud Computing, Internet of Things, and Big Data Analytics have been selected due to their relevant effects on real-time information sharing within different SC echelons rather than inside one echelon. Moreover, the implementation of these technologies in real SC requires high investments. Also, due to the increased complexity of the SC after applying these technologies, their impacts on SC behavior and performance should be determined precisely. This paper proposes simulation as a cost-effective and comprehensive method to investigate how digital technologies affect SC performance. A three echelon manufacturing SC has been simulated by using System Dynamics (SD) modeling under different scenarios in both traditional and digital SCM. The results reveal a significant improvement of SC performance, in terms of inventory level and cost as well as order fulfillment ratio, in digital SCs compared to traditional SCs. Future research will further develop the model by validating the simulation results with real cases from the industry