scale diversity and determinants of labour migration in europe while global migration is increasing internal eu migration flows have only increased slowly this paper contributes to a better understanding of the determinants and scale of european migration it surveys previous historical experiences and empirical findings including the recent eastern enlargements the determinants of migration before and after the 2004 enlargement and in the eu15 and eu10 countries are analysed using individual data on migration intentions in addition perceptions about the size of migration after the enlargement are studied the potential emigrant from both old and new eu member states tends to be young better educated and to live in larger cities people from the eu10 with children are less likely to move after enlargement in comparison to those without family there exists a correlation between individual perceptions about the scale of migration and actual flows better educated and left oriented individuals in the eu15 are less likely to perceive these flows as important

banking deregulation and industry structure evidence from the french banking reforms of 1985 we investigate how the deregulation of the french banking industry in the 1980s affected the real behavior of firms and the structure and dynamics of product markets following deregulation banks are less willing to bail out poorly performing firms and firms in the more bank dependent sectors are more likely to undertake restructuring activities at the industry level we observe an increase in asset and job reallocation an improvement in allocative efficiency across firms and a decline in concentration overall these findings support the view that a more efficient banking sector helps foster a schumpeterian process of creative destruction many economies around the world are characterized by heavily regulated bank

liquidity risk and occupational choices we explore which financial constraints matter the most in the choice of becoming an entrepreneur we consider a randomly assigned welfare program in rural mexico and show that cash transfers signi cantly increase entry into entrepreneurship we then exploit the cross household variation in the timing of these transfers and find that current occupational choices are significantly more responsive to the transfers expected for the future than to those currently received guided by a simple occupational choice model we argue that the program has promoted entrepreneurship by enhancing the willingness to bear risk as opposed to simply relaxing current liquidity constraints

reducing the bullwhip effect looking through the appropriate lens demand amplification now frequently referred to as bullwhip is potentially a very costly phenomenon it can lead to stock outs large and expensive capacity utilisation swings lower quality products and considerable production transport on costs as deliveries are ramped up and down at the whim of the supply chain however the detection of bullwhip depends on which lens is used this in turn depends on the background and requirements of various players within the value stream to gain insight into this scenario we exploit a relatively simple replenishment model because new and novel analytic solutions have been derived for all important performance metrics comparison of the competing bullwhip measures is thereby greatly streamlined in the complex real world the likelihood is that supply chains will generate even greater inconsistency between alternative variance shock and filter lens viewpoints

extended benefits and the duration of ui spells evidence from the new jersey extended benefit program abstract this paper examines the impact on the duration of unemployment insurance receipt of a politically motivated program that offered 13 weeks of extended benefits for 6 months in 1996 using state level data and individual administrative records from before during and after the program we find that it raised the fraction of claimants who exhausted their regular benefits by 1 3 percentage points had the program run long enough to affect claimants from the first day of their spell the fraction exhausting would have risen by 7 percentage points and the average recipient would have collected regular benefits for one extra week

international sourcing and supply chain stability an international supply chain is conceptualized as a complex dynamic system in which disruptions interact with long shipping and lead times to generate costs findings from a case study and simulation model indicate that demand related disruptions created substantial and unexpected costs in terms of expedited shipping high inventories and lower demand fulfillment production related disruptions declined over time but demand related disruptions did not implications for management are discussed

environmental policy adjustment costs and behavior of the firm abstract the effects of environmental policy in the form of emission charges or emission limits on the firm s optimal choices of productive and abatement inputs are analyzed short run and long run impacts on inputs and the properties of static emission function are determined through comparative static analysis comparative dynamics reveal the properties of the cumulative emission function and the cumulative shadow cost of emission limits function

the analysis of bullwhip effect in a hmms type supply chain the aim of the paper is to investigate the well known bullwhip effect of supply chains control theoretic analysis of bullwhip effect is extensively analyzed in the literature with the laplace transform this paper tries to examine the effect for an extended holt modigliani muth simon model a two stage supply chain supplier manufacturer is studied with quadratic costs functional it is assumed that both firms minimize the relevant costs the order of the manufacturer is delayed with a known constant two cases are examined supplier and manufacturer minimize the relevant costs decentralized and a centralized decision rule the question is answered how to decrease the bullwhip effect

production chains and aggregate output volatility abstract a production chain s aggregate output volatility depends upon a number of factors including the number of firms in a chain the management strategy of the firms the point at which products are differentiated lead times and the persistence of demand shocks the influence of these factors is quantified here with an n firm model of the production chain under pure production to stock pts the firms in the chain respond simultaneously to a demand shock producing a positive covariance across firms that raises aggregate volatility under production to order pto the chain s response to a demand shock is staggered but when demand shocks are persistent there is a catch up effect that raises the volatility of each firm s production above that of a firm that under pts nevertheless pto chains typically exhibit less volatility than pts chains thanks to the covariance effect further simulations demonstrate that the production chain stabilizes as the number of production cycles in an observation period increases

the carnegie conjecture some empirical evidence this paper examines tax return generated data on the labor force behavior of people before and after they receive inheritances the results are consistent with andrew carnegie s century old assertion that large inheritances decrease a person s labor force participation for example a single person who receives an inheritance of about 150 000 is roughly four times more likely to leave the labor force than a person with an inheritance below 25 000 additional albeit weaker evidence suggests that large inheritances depress labor supply even when participation is unaltered warren kendall heir to an insurance company fortune says he s worth about 5 million and has an income of about oh 300 and some thousand a year h e has never held a job or wanted to going down to sea in cruise ships is his full time pursuit he estimates that he has taken about 250 cruises over the past couple of decades spending at least 50 percent to 70 percent of the year afloat morgenthaler 1991 p al

who is against immigration a cross country investigation of individual attitudes toward immigrants abstract this paper empirically analyzes economic and noneconomic determinants of individual attitudes toward immigrants within and across countries the two survey data sets used covering a wide range of developed and developing countries make it possible to test for interactive effects between individual characteristics and country level attributes in particular theory predicts that the correlation between pro immigration attitudes and individual skill should be related to the skill composition of natives relative to immigrants in the destination country skilled individuals should favor immigration in countries where natives are more skilled than immigrants and oppose it otherwise results based on direct and indirect measures of the relative skill composition are consistent with these predictions noneconomic variables also are correlated with immigration attitudes but they don t alter significantly the labor market results

the bullwhip effect in supply chains an overestimated problem abstract a phenomenon that is now well known as the bullwhip effect suggests that the variability of orders increases as they move up the supply chain from retailers to wholesalers to manufacturers to suppliers in this paper we will focus mainly on measuring the bullwhip effect existing approaches that aim at quantifying the bullwhip effect neglect the network structure of supply chains by only assuming a simple two stage supply chain consisting of a single retailer and a single manufacturer some of the relevant risk pooling effects associated with the network structure of supply chains are disregarded risk pooling effects arise when the orders which a retailer receives from its customers are statistically correlated with a coefficient of correlation less than one when analyzing the bullwhip effect in supply chains however the influence of risk pooling has to be considered the fact that these influences have not yet been analyzed motivates the research presented in this paper we will show that the bullwhip effect is overestimated if just a simple supply chain is assumed and risk pooling effects are present

inventory management for stochastic lead times with order crossovers we study the impact of stochastic lead times with order crossover on inventory costs and safety stocks in the order up to out policy to motivate our research we present global logistics data which violates the traditional assumption that lead time demand is normally distributed we also observe that order crossover is a common and important phenomenon in real supply chains we present a new method for determining the distribution of the number of open orders using this method we identify the distribution of inventory levels when orders and the work in process are correlated this correlation is present when demand is auto correlated demand forecasts are generated with non optimal methods or when certain ordering policies are present our method allows us to obtain exact safety stock requirements for the so called proportional order up to pout policy a popular implementable linear generalization of the out policy we highlight that the out replenishment policy is not cost optimal in global supply chains as we are able to demonstrate the pout policy always outperforms it under order cross over we show that unlike the constant lead time case minimum safety stocks and minimal inventory variance do not always lead to minimum costs under stochastic lead times with order crossover we also highlight an interesting side effect of minimizing inventory costs under stochastic lead times with order crossover with the pout policy an often significant reduction in the order variance

analysis of compound bullwhip effect causes abstract this research investigates compound causes of the bullwhip effect bwe by considering an inventory system with multiple price sensitive demand streams joint price and demand dynamics are captured by a vector time series process that incorporates the stochastic co movements in price and demand we study two bwe measures one for each demand stream individually and one for the aggregated demand we show that demand parameters including demand autocorrelation cross correlation and price sensitivity serve as root causes of the bwe we prove that the impact of these parameters on the bwe can be additively decomposed conditions are established under which a pair of simultaneous compound causes may attenuate or dampen the bwe when demand streams are aggregated we derive a pooling factor that quantifies the impact of demand aggregation on order stability when positive the pooling factor corresponds to a synergy effect that captures the gain in the stability of the pooled orders conditions for the existence of the synergy effect are obtained for several special cases involving a zero leadtime we also discuss how our analytical findings can be managerially applied to bullwhip mitigation strategies

can unemployment insurance spur entrepreneurial activity evidence from france we evaluate the effect of downside insurance on self employment we exploit a large scale reform of french unemployment benefits that insured unemployed workers starting businesses the reform significantly increased firm creation without decreasing the quality of new entrants firms started postreform were initially smaller but their employment growth productivity and survival rates are similar to those prereform new entrepreneurs characteristics and expectations are also similar finally jobs created by new entrants crowd out employment in incumbent firms almost one for one but have a higher productivity than incumbents these results highlight the benefits of encouraging experimentation by lowering barriers to entry

a unified theory of the dynamics of closed loop supply chains we investigate the dynamics of a closed loop supply chain with first order auto regressive ar 1 demand and return processes we assume these two processes are cross correlated the remanufacturing process is subject to a random triage yield remanufactured products are considered as goodas new and used to partially satisfy market demand newly manufactured products make up the remainder we derive the optimal linear policy in our closed loop supply chain setting to minimise the manufacturer s inventory costs we show that the lead time paradox can emerge in many cases in particular the auto and cross correlation parameters and variances of the error terms in the demand and the returns as well as the remanufacturing lead time all influence the existence of the lead time paradox finally we propose managerial recommendations for manufacturers

the stabilizing effect of inventory in supply chains this paper presents a hierarchical model framework for the analysis of the stabilizing effect of inventories in multiechelon manufacturing distribution supply chains this framework is used to compare the variance of demand to the variance of replenishment orders at different echelons of the system e g retailer wholesaler empirical data and experience with management games suggest that in most industries inventory management policies can have a destabilizing effect by increasing the volatility of demand as it passes up through the chain the bullwhip effect our model helps to explain these observations and indicates mechanisms that can promote stabilization the analysis results also define sufficient conditions for the existence of stabilization and relate these conditions to the optimality of myopic control policies

dual citizenship allowance and migration flow an origin story what effect does variation in dual citizenship policies of both sending and receiving societies have on bilateral migration flow employing a modified gravity model we use a new dual citizenship d

evaluating alternative capacity strategies in semiconductor manufacturing under uncertain demand and price scenarios abstract because product demand is very volatile and machine and process technologies are advanced at a rapid pace capacity planning and investment in the semiconductor industry is a challenging task many studies have addressed mid and short term machine portfolio planning tasks of capacity planning however capacity planning should be considered in a framework of strategy planning in order to address the whole problem this paper describes a method of analysis for adapting capacity strategy to changing business environment the paper has three major parts in the first part empirical data analysis of a case study company yields predictive formulas for production and capacity costs the uncertainty of demand is also calibrated using the geometric brownian motion process in the second part experiments are designed to simulate demand and profit scenarios for comparing two capacity strategies in the third part the resultant data of simulation are analysed to gain insights to the relative performance of the two strategies in various scenarios the analysis method provides a framework for formulating capacity strategy and for integrating capacity planning with business planning

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 can be extracted from this analysis such as the role of benefit sharing strategies in order to guarantee the advantage of investments in connectivity technologies

unemployment insurance recall expectations and unemployment outcomes this paper empirically examines the importance of explicitly accounting for the layoff rehire process in the analysis of unemployment outcomes in the united states we find that the spells of individuals who initially expect to be recalled account for much more of the unemployment of unemployment insurance ui recipients than do spells actually ending in recall our results indicate that the recall and new job escape rates from unemployment have quite different time patterns and are often affected in opposite ways by explanatory variables we also find that the probability of leaving unemployment both through recalls and new job finding increases greatly around the time that ui benefits lapse over the past fifteen years many studies have empirically analyzed the determinants of individual unemployment spell durations in the united states much of this literature has used a job search framework in which the unemployed are viewed as permanently displaced workers who are unattached to jobs the possibility of recall to a former job a process not requiring search has been omitted from explicit consideration in the majority of these studies 2 an explicit treatment of the layoff rehire process is necessary for a proper understanding of the determinants of unemployment durations and of the impacts of unemployment policies in the united states for at least three reasons first temporary layoffs in which workers are often rehired by their original employers are a quantitatively quite important feature of the u s labor market 3 second expectations concerning the likelihood of recall are likely to affect the responses of employers and unemployed workers to labor market interventions such as reemployment bonuses and subsidies

a supply chain as a series of filters or amplifiers of the bullwhip effect abstract the bullwhip effect refers to the phenomenon of amplification and distortion of demand in a supply chain by eliminating or controlling this effect it is possible to increase product profitability reducing useless costs such as stock out and obsolescence costs the main focus of this work is to study a single product serial supply chain in which a control parameter can switch the chain from a series of filters to a series of amplifiers of the bullwhip effect and to analyse how the optimal values of the parameters change when discontinuities in order policy are considered furthermore it is also shown that the bullwhip itself it is not a good index of the chain s performance because it does not consider the oscillations that occur in the inventories which also may affect the supply chain performance

economic research and labour immigration policy the design of labour immigration policy requires nation states to make fundamental decisions on how to regulate i the number of migrants to be admitted ii the selection of migrants and iii the rights of migrants after admission in practice the debate over these three elements of immigration policy involves a wide range of economic social legal moral and political considerations recognizing the inherent inter disciplinarity of the subject this paper focuses on the implications of economic theories and research for regulating the number selection and rights of migrant workers in high income countries it examines the asymmetric economic interests of migrant receiving and migrant sending countries in the debate over the optimal design of labour immigration policy and in light of this analysis provides a brief economic assessment of the core components of labour immigration policy in the uk

financial development bank ownership and growth or does quantity imply quality abstract in 1980 india nationalized its large private banks this induced different bank ownership patterns across different towns allowing credible identification of the effects of bank ownership on financial development lending rates and the quality of intermediation as well as employment and investment credit markets with nationalized banks experienced faster credit growth during a period of financial repression nationalization led to lower interest rates and lower quality intermediation and may have slowed employment gains in trade and services development lending goals were met but these had no impact on the real economy

the production and inventory behavior of the american automobile industry understanding inventory movements is central to an understanding of business cycles this paper presents an empirical study of the behavior of inventories in the automobile industry it finds that inventory behavior is well explained by the assumption of intertemporal optimization with rational expectations the underlying cost structure appears to have substantial costs of changing production as well as substantial costs of being away from target inventory thelatter being a function of current sales given this cost structure whether inventory behavior is stabilizing or destabilizing depends on the characteristics of the demand process in the automobile industry inventory behavior is destabilizing the variance of production is larger than the variance of sales

revisiting the value of information sharing in two stage supply chains abstract there is a substantive amount of literature showing that demand information sharing can lead to considerable reduction of the bullwhip effect inventory costs the core argument analysis underlying these results is that the downstream supply chain member the retailer quickly adapts its inventory position to an updated end customer demand forecast however in many real life situations retailers adapt slowly rather than quickly to changes in customer demand as they cannot be sure that any change is structural in this paper we show that the adaption speed and underlying unknown demand process crucially affect the value of information sharing for the situation with a single upstream supply chain member manufacturer and a single retailer we consider two demand processes stationary or random walk these represent two extremes where a change in customer demand is never or always structural respectively the retailer and manufacturer both forecast demand using a moving average where the manufacturer bases its forecast on retailer demand without information sharing but on end customer demand with information sharing in line with existing results the value of information turns out to be positive under stationary demand one contribution though is showing that some of the existing papers have overestimated this value by making an unfair comparison our most striking and insightful finding is that the value of information is negative when demand follows a random walk and the retailer is slow to react slow adaptation is the norm in real life situations and deserves more attention in future research exploring when information sharing indeed pays off

analyzing the effect of the inventory policy on order and inventory variability with linear control theory in this paper we apply linear control theory to study the effect of various inventory policies on order and inventory variability which are key drivers of supply chain performance in particular we study a two echelon supply chain with a stationary demand pattern under the influence of three inventory policies an inventory on hand policy that bases orders on the visible inventory at an installation an installation stock policy that bases orders on the inventory position on hand plus on order inventory at an installation and an echelon stock policy that bases orders on the inventory position at that installation and all downstream installations we prove analytically that the inventory on hand policy is unstable in practical settings confirming analytically what has been observed in experimental settings and in practice we also prove that the installation stock and echelon stock policies are stable and analyze their effect on order and inventory fluctuation specifically we show the general superiority of the echelon stock in our setting and demonstrate analytically the effect of forecasting parameters on order and inventory fluctuations confirming the results in other research

small sample uncertainty aspects in relation to bullwhip effect measurement abstract the bullwhip effect as a concept has been known for almost half a century starting with the forrester effect the bullwhip effect is allegedly observed in many supply chains and it is generally accepted as a potential malice despite this the bullwhip effect still seems to be first and foremost a conceptual phenomenon some even simply denies that the phenomenon exists at all in practice this of course makes it important to perform measurements because only what gets measured gets done as the saying goes in analytics few measurements are reported in the literature however typically based on standard statistical assumptions in the case of a standard measurement of the bullwhip effect independence amongst the participating variables are required amongst others but this is definitely known not to be perfectly true if any systematic control at all have taken place in the supply chain this paper analyses the bullwhip measurement implications in case the standard test assumptions are violated and illustrates how to improve on the testing setup this is further done with a special emphasis on the unavoidable small sample aspects relating to such measurement in practice which typically renders all statistical asymptotic or robust arguments quite unusable it is shown how h 0 95 confidence test intervals still easily can be obtained numerically in such cases

a human experiment on inventory decisions under supply uncertainty abstract controlled human experiments are adopted in this paper to investigate the impact of supply uncertainty on buyers inventory management the experiments aim at assessing the impact of one specific source of supply chain uncertainty namely stochastic lead times on inventory holdings and the extent of the bullwhip effect three experimental treatments are run within the framework of the beer game manipulating variability in demand and in lead times results confirm that the bullwhip effect arises in all experimental treatments and that the variance of orders is higher under stochastic lead times analysis of players behaviour in the course of the game suggests that players react to higher uncertainty by holding fewer inventories a behaviour consistent with the predictions of some psychological models of choice under ambiguity

information distortion in a supply chain the bullwhip effect this article originally appeared in management science april 1997 volume 43 number 4 pp 546 558 published by the institute of management sciences consider a series of companies in a supply chain each of whom orders from its immediate upstream member in this setting inbound orders from a downstream member serve as a valuable informational input to upstream production and inventory decisions this paper claims that the information transferred in the form of orders tends to be distorted and can misguide upstream members in their inventory and production decisions in particular the variance of orders may be larger than that of sales and distortion tends to increase as one moves upstream a phenomenon termed bullwhip effect this paper analyzes four sources of the bullwhip effect demand signal processing rationing game order batching and price variations actions that can be taken to mitigate the detrimental impact of this distortion are also discussed

production inventory control under environmental constraints the aim of the paper is to investigate how environmental policies in the form of emission charges or emission limits affect the production inventory decisions of a firm our framework applies control theory to analyze optimal production policies the paper modifies the holt modigliani muth simon model

house prices collateral and self employment this paper explores the role of the collateral lending channel to facilitate small business starts and self employment in the period before the financial crisis of 2008 we document that between 2002 and 2007 areas with a bigger run up in house prices experienced a strong increase in employment in small businesses compared to employment in large firms in the same industries this increase in small business employment was particularly pronounced in industries that need little startup capital and can thus more easily be financed out of increases in housing as collateral our results highlight the importance of the collateral lending channel during the period of the house price boom in the creation of small establishments we show that this effect is separate from the aggregate demand channel that relies on home equity based borrowing leading to increased demand and employment creation

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 of experiment we perform a robust what if analysis of a clsc under a variety of operational and market conditions results show that ceteris paribus clsc outperforms a forward supply chain both in mono echelon and multi echelon structures and under both stationary and turbulent market demands furthermore reducing remanufacturing lead time and promoting information transparency may be crucial to improve clsc dynamics finally we use the research findings to provide interesting managerial consideration about how to reduce unnecessary operational members costs

migration and institutions evidence from internal eu mobility despite the formal achievement of the free movement of labour within the eu the institutional characteristics of the labour markets of the member states may influence european mobility the paper seeks empirical evidence of the relationship between labour market institutions and intra eu migrations estimating a gravity model for bilateral migration for the period 2001 11 the results indicate that trade union density negatively correlates with the size of bilateral migrations destinations with relatively high union density are associated with lower migration inflows since these countries tend to have a relatively flat earnings distribution it is also investigated whether their earnings structure reduces their attractiveness as destinations hindering the access to their labour market even if a dependence between the earnings dispersion and migrations is found trade union density remains the main driver of migration patterns clear effects of employment protection on eu mobility are not found

reduction of the value of information sharing as demand becomes strongly auto correlated information sharing has been identified in the academic literature as one of the most important levers to mitigate the bullwhip effect in supply chains a highly cited article on the bullwhip effect has claimed that the percentage inventory reduction resulting from information sharing in a two level supply chain when the downstream demand is autoregressive of order one is an increasing function of the autoregressive parameter of the demand in this paper we show that this is true only for a certain range of the autoregressive parameter and there is a maximum value beyond which the bullwhip ratio at the upstream stage is reduced and the percentage inventory reduction resulting from information sharing decreases towards zero we also show that this maximum value of the autoregressive parameter can be as high as 0 7 which represents a common value that may be encountered in many practical contexts this means that large benefits of information sharing cannot be assumed for those stock keeping units skus with highly positively auto correlated demand instead equally careful analysis is needed for these items as for those skus with less strongly auto correlated demand

the role of forecasting on bullwhip effect for e scm applications abstract the bullwhip effect represents the information distortion in customer demand between orders to supplier and sales to the buyer demand forecasting is one of the main causes of the bullwhip effect the purpose of this study is to analyze the impact of exponential smoothing forecasts on the bullwhip effect for electronic supply chain management e scm applications a simulation model is developed to experiment the different scenarios of selecting right parameters for the exponential smoothing forecasting technique it is found that longer lead times and poor selection of forecasting model parameters lead to strong bullwhip effect in e scm in contrast increased seasonality helps to reduce the bullwhip effect the most significant managerial implication of this study lies in the need to reduce lead times along the e supply chain to mitigate the bullwhip effect while high seasonality would reduce the forecast accuracy it has a positive influence on the reduction of bullwhip effect e scm managers are therefore strongly suggested to utilize exponential smoothing by selecting lower values for and and a mid value for to keep the bullwhip ratio low while at the same time to increase forecast accuracy

the bullwhip effect progress trends and directions the 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

the bullwhip effect in supply chain networks this paper analyzes the propagation and amplification of order fluctuations i e the bullwhip effect in supply chain networks operated with linear and time invariant inventory management policies the supply chain network is allowed to include multiple customers e g markets any network structure with or without sharing information the paper characterizes the stream of orders placed by any supplier for any stationary customer demand processes and gives exact formulas for the variance of the orders placed and the amplification of order fluctuations the paper also derives robust analytical conditions based only on inventory management policies to predict the presence of the bullwhip effect for any network structure any inventory replenishment policies and arbitrary customer demand processes numerical examples show that the analytical results accurately quantify the bullwhip effect managerial insights are drawn from the analysis the methodology presented in this paper generalizes those in previous studies for serial supply chains

characterization of the bullwhip effect in linear time invariant supply chains some formulae and tests the authors analyze the bullwhip effect in multistage decentralized supply chains operated with linear and time invariant inventory management policies the focus is on robustness the supply chain is modeled as a single input single output control system driven by arbitrary customer demands the authors derive robust analytical conditions to predict the presence of the bullwhip effect and bound its magnitude based only on the way inventories are managed these results hold independently of the customer demand the authors also characterize the stream of orders placed at any stage of the chain when the customer demand process is known and ergodic and give an exact formula for the variance of the orders placed this formula generalizes existing results by broadening the class of inventory replenishment policies and customer demand processes to which it applies the authors also show that the bullwhip effect can be mitigated by introducing commitments for future orders into the ordering policies

capacity restrictions and supply chain performance modelling and analysing load dependent lead times abstract several studies have reported that capacitated supply chains may benefit from an improved dynamic performance as compared to unconstrained ones this occurs as a consequence of the capacity limit acting as a production smoothing filter in this research the relationship between capacity restrictions and the operational performance of supply chains is investigated from a novel perspective i e we assume that the influence of capacity constraints on lead times depends on the supply chain s responsiveness under these circumstances the experiments show that there is a negative effect of capacity constraints on supply chain performance both in terms of process efficiency internal and customer satisfaction external nonetheless the magnitude of this impact greatly depends on the responsiveness of the firm market conditions and adopted policies for inventory management more specifically the combination of tight capacity restrictions and low responsiveness significantly contributes to decrease supply chain performance which may be very damaging for the dynamic behavior of the system in this sense efficient capacity planning proves to be essential to prevent the supply chain from entering into a vicious circle

transfer function analysis of forecasting induced bullwhip in supply chains the present paper analyses the bullwhip problem generated by exponential smoothing algorithms in both stand alone passing on orders mode and within inventory controlled feedback systems results are predicted from transfer function analysis and then confirmed by simulation via the bullwhip explorer supply chain software a novel feature of the paper is the introduction of the matched filter concept into the exponential smoothing algorithm this adjusts the value of the smoothing constant depending on whether the constant linear or quadratic forecasting model is used it is shown that matching the filter via noise bandwidth equalises the output variance when the demand is a random signal hence some of the unwanted effects of using the linear and quadratic forecasting models are attenuated however there is little benefit obtained by using sophisticated forecasting methods within inventory controlled feedback systems as their tracking ability is reduced

decomposition of ireland s carbon emissions from 1990 to 2010 an extended kaya identity in recent decades ireland has been an important example of a development pathway where rapid economic growth was accompanied by rising energy demand and increasing carbon emissions understanding the driving forces of carbon emissions is necessary for policy formulation and decomposition analysis is widely used for this purpose this study uses an extended kaya identity as the scheme and applies the log mean divisia index lmdi i as the decomposition technique change in carbon emissions is decomposed from 1990 to 2010 and includes a measure of the effect of renewable energy penetration results illustrate that scale effects of affluence and population growth act to increase emissions and are countered primarily by energy intensity and fossil fuel substitution renewable energy penetration has a minor effect but has been increasing in recent years policy will need to significantly reduce intensity and increase renewables if applicable targets are to be reached this requires not only a comprehensive suite of policies and measures but emphasis on the development path and non technical change for optimal outcomes

on bullwhip in a family of order up to policies with arma 2 2 demand and arbitrary lead times a number of papers have recently appeared that investigate the bullwhip effect the variance amplification of ordering decisions in the supply chain produced by the order up to replenishment policy an adapted policy with a proportional inventory position feedback controller has shown improved bullwhip behaviour the dynamic behaviour of this so called proportional order up to policy has been investigated for arbitrary lead times and several demand models such as i i d demand and autoregressive moving average ar 1 and arma 1 1 models it has been shown that for a correct choice of the feedback parameter the bullwhip effect can always be avoided however less attractive properties of this policy have also become clear herein we investigate the behaviour of the proportional order up to policy for arma 2 2 demand with arbitrary lead times in order to compensate for possible weaknesses of the proportional out policy we propose another replenishment rule that accounts for the characteristics of the demand in a superior manner the characteristics of both policies are compared for several parameter settings of the arma 2 2 model finally the consequences of our full state feedback order up to policy are discussed

managing the trade off implications of global supply abstract the cost versus response trade off is a growing logistics issue due to many markets being increasingly characterised by demand uncertainty and shorter product life cycles this is exacerbated further with supply increasingly moving to low cost global sources however the poor response implications of global supply are often not addressed or even acknowledged when undertaking such decisions consequently various practical approaches to minimising postponing or otherwise managing the impact of the demand uncertainty are often only adopted retrospectively even though such generic solutions are documented through case examples we lack effective tools and concepts to support the proactive identification and resolution of such trade offs this paper reports on case based theory building research involving three cases from the uk and usa used in developing a conceptual model with associated tools in support of such a process

migration and farm technical efficiency evidence from kosovo this article investigates the effect of migration on farm technical efficiency drawing on a large and representative sample of agricultural households in kosovo a two stage estimation procedure is applied a frontier technique to estimate the effect of migration on farm efficiency followed by a propensity score based matching approach to robustly estimate the sample average effect on efficiency for different levels of migration intensity migration is found to have an efficiency decreasing effect which is amplified for better educated workers the observed negative effect of migration on efficiency is evident even at low levels of migration intensity

work incentive effects of taxing unemployment benefits before 1979 unemployment insurance ui benefits were not treated as taxable income in the united states several economists criticized this policy on the ground that not taxing ui benefits while taxing earned income allegedly encourages unemployed persons to conduct longer than socially optimal job searches since 1979 however ui benefits received by persons in higher income families have been subject to income tax this paper investigates whether the introduction of benefit taxation has had the predicted effect of reducing unemployment duration the study uses data on a sample of persons that filed for ui in 1978 or 1979 to examine whether high income claimants collected benefits for shorter periods after the tax change than they did before benefits became taxable as part of the empirical analysis the paper develops a generalization of the weibull distribution and applies a limited dependentvariable technique for this distribution similar to the tobit technique for the normal distribution despite some variation in the results from different model specifications the analysis presents persuasive evidence of a tax effect on unemployment duration the 1979 policy change is estimated to have reduced average compensated unemployment duration among the sampled high income claimants by about one week

returns to capital in microenterprises evidence from a field experiment small and informal firms account for a large share of employment in developing countries the rapid expansion of microfinance services is based on the belief that these firms have productive investment opportunities and can enjoy high returns to capital if given the opportunity however measuring the return to capital is complicated by unobserved factors such as entrepreneurial ability and demand shocks which are likely to be correlated with capital stock the authors use a randomized experiment to overcome this problem and to measure the return to capital for the average microenterprise in their sample regardless of whether they apply for credit they accomplish this by providing cash and equipment grants to small firms in sri lanka and measuring the increase in profits arising from this exogenous positive shock to capital stock after controlling for possible spillover effects the authors find the average real return to capital to be 5 7 percent a month substantially higher than the market interest rate they then examine the heterogeneity of treatment effects to explore whether missing credit markets or missing insurance markets are the most likely cause of the high returns returns are found to vary with entrepreneurial ability and with measures of other sources of cash within the household but not to vary with risk aversion or uncertainty

inventory performance under pack size constraints and spatially correlated demand abstract motivated by a problem facing a large retailer we consider the impact of pack size on the performance of a periodic review inventory system in the presence of spatial i e between retailers correlation of demand which we model using an equicorrelated multivariate poisson distribution employing simulation we utilise a full factorial experiment to provide support for decisions on product and supplier selection and whether or not packs should be split during distribution we consider variables such as pack size correlation and the number of branches and discuss how they and their interactions impact performance metrics such as inventory and shortage levels and the bullwhip effect

an empirically simulated investigation of the impact of demand forecasting on the bullwhip effect evidence from u s auto industry this study empirically examines the impacts of three major aspects of demand forecasting on the magnitude of the bullwhip effect three research questions are addressed to investigate the association between 1 forecast accuracy 2 aggregate forecasting and 3 responsive forecasting and the bullwhip effect using forecasted demand generated from popular time series forecasting models and real life demand data the study investigates the relationship between the forecasted results and the consequential bullwhip effect the findings show that the forecasting methods used lead to the variation of the bullwhip effect moreover the lead time reduction and the stable demand forecast are beneficial to reduce the bullwhip effect however our empirical results differ from previous findings in two ways i improving forecast accuracy does not necessarily reduce the bullwhip effect and ii aggregate forecasting does not always reduce the bullwhip effect

self selection and the earnings of immigrants this paper analyzes the way in which the earnings of the immigrant population may be expected to differ from the earnings of the native population because of the endogeneity of the decision to migrate the empirical study shows that differences in the u s earnings of immigrants with the same measured skills but from different home countries are attributable to variations in political and economic conditions in the countries of origin at the time of migration excerpt

managing supply chain demand variability with scheduled ordering policies this paper studies supply chain demand variability in a model with one supplier and n retailers that face stochastic demand retailers implement scheduled ordering policies orders occur at fixed intervals and are equal to some multiple of a fixed batch size a method is presented that exactly evaluates costs previous research demonstrates that the supplier s demand variance declines as the retailers order intervals are balanced i e the same number of retailers order each period this research shows that the supplier s demand variance will generally decline as the retailers order interval is lengthened or as their batch size is increased lower supplier demand variance can certainly lead to lower inventory at the supplier this paper finds that reducing supplier demand variance with scheduled ordering policies can also lower total supply chain costs

the extension and exploitation of the inventory and order based production control system archetype from 1982 to 2015 in 1994 through classic control theory john naim and towill developed the automatic pipeline inventory and order based production control system apiobpcs which extended the original iobpcs archetype developed by towill in 1982 well recognised as a base framework for a production planning and control system due to the prevalence of the two original models in the last three decades in the academic and industrial communities this paper aims to systematically review how the iobpcs archetypes have been adopted exploited and adapted to study the dynamics of individual production planning and control systems and whole supply chains using various databases such as scopus web of science google scholar 111 papers we found that the iobpcs archetypes have been studied regarding the a modification of four inherent policies related to forecasting inventory lead time and pipeline to create a family of models b adoption of the iobpcs family to reduce supply chain dynamics and in particular bullwhip c extension of the iobpcs family to represent different supply chain scenarios such as order book based production control and closed loop processes simulation is the most popular method adopted by researchers and the number of works based on discrete time based methods is greater than those utilising continuous time approaches most studies are conceptual with limited practical applications described future research needs to focus on cost flexibility and sustainability in the context of supply chain dynamics and although there are a few existing studies more analytical approaches are required to gain robust insights into the influence of nonlinear elements on supply chain behaviour also empirical exploitation of the existing models is recommended

production strategies under environmental constraints continuous time model with concave costs abstract the aim of this paper is to investigate how environmental policies in the form of emission charges or emission limits affect the production inventory decisions of a firm our framework applies control theory to analyze optimal production policies the paper modifies the results of wirl european journal of operational research 55 1991 191 to the case of concave production costs

willingness to move for work and unemployment duration in spain this paper examines unemployed workers willingness to move for work and its relationship to their unemployment duration in spain we use a hypothetical question in the spanish labour force survey would you accept a job offer which implied a change of residence the main finding is that while family responsibility age and education are important in determining individuals migration willingness the duration of unemployment does not show any significant effect even after controlling for unobserved fixed individual heterogeneity however the significant improvement in migration willingness after the exhaustion of unemployment benefits or when other household members become unemployed suggests that economic incentives could play an important role in increasing worker mobility we also find that job finding probability is significantly higher among those with positive migration attitudes than among others universidad del pais vasco

are immigrants favorably self selected one of the standard propositions in the migration literature is that migrants tend to be favorably self selected for labor market success that is economic migrants are described as tending on average to be more able ambitious aggressive entrepreneurial or otherwise more favorably selected than similar individuals who choose to remain in their place of origin in recent years there have been challenges to the general proposition of the favorable selectivity of migrants in addressing this issue this paper considers alternative specifications of the migration model that are relevant for the issue of migrant selectivity excerpt

state space investigation of the bullwhip problem with arma 1 1 demand processes using state space techniques we study a myopic order up to policy the policy is myopic because it is optimal at minimising local inventory holding and shortage costs in particular we study the bullwhip effect produced by the replenishment policy reacting to a stochastic arma 1 1 demand processes we reveal that bullwhip is fundamentally caused by the co variance between the inventory level and the demand forecast we go on to highlight the impact of a simple control engineering inspired bullwhip reduction technique a proportional controller in the inventory feedback loop although it can be shown this approach is always able to remove bullwhip we expose that it is not possible to arbitrarily tune the proportional controller without knowing in advance the likely structure of the demand process we conclude with an investigation of trade offs and optimisations in the order and inventory variance and their sum produced by our policy

demand fluctuation and chaotic behaviour by interaction between customers and suppliers this paper presents an investigation on simulation of interaction between customers and suppliers in a three tier supply chain system in the simulation customers respond to the price discount offer made by the supplier and the supplier makes adjusts the price according to stock held the simulation shows that the behaviour of such interaction exhibits deterministic chaos it is found that the attractors of the model move with the environment and the initial states thus the bifurcating points in such a system are unable to provide a guideline in system design to avoid chaos

rogue seasonality detection in supply chains rogue seasonality or unintended cyclic variability in order and other supply chain variables is an endogenous disturbance generated by a company s internal processes such as inventory and production control systems the ability to automatically detect diagnose and discriminate rogue seasonality from exogenous disturbances is of prime importance to decision makers this paper compares the effectiveness of alternative time series techniques based on fourier and discrete wavelet transforms autocorrelation and cross correlation functions and autoregressive model in detecting rogue seasonality rogue seasonalities of various intensities were generated using different simulation designs and demand patterns to evaluate each of these techniques an index for rogue seasonality based on the clustering profile of the supply chain variables was defined and used in the evaluation the fourier transform technique was found to be the most effective for rogue seasonality detection which was also subsequently validated using data from a steel supply network

coordinating lead times and safety stocks under autocorrelated demand we consider a supply chain in which orders and lead times are linked endogenously as opposed to assuming lead times are exogenous this assumption is relevant when a retailer s orders are produced by a supplier with finite capacity and replenished when the order is completed the retailer faces demands that are correlated over time either positively or negatively which may for example be induced by a pricing or promotion policy the auto correlation in demand affects the order stream placed by the retailer onto the supplier and this in turn influences the resulting lead times seen by the retailer since these lead times also determine the retailer s orders and its safety stocks which the retailer must set to cover lead time demand there is a mutual dependency between orders and lead times the inclusion of endogenous lead times and autocorrelated demand represents a better fit with real life situations however it poses some additional methodological issues compared to assuming exogenous lead times or stationary demand processes that are independent over time by means of a markov chain analysis and matrix analytic methods we develop a procedure to determine the distribution of lead times and inventories that takes into account the correlation between orders and lead times our analysis shows that negative autocorrelation in demand although more erratic improves both lead time and inventory performance relative to iid demand positive correlation makes matters worse than iid demand due to the endogeneity of lead times these effects are much more pronounced and substantial error may be incurred if this endogeneity is ignored

quantifying the bullwhip effect using two echelon data a cross industry empirical investigation the bullwhip effect denotes the phenomenon whereby demand variability is amplified from a downstream site buyer to an upstream site supplier in the supply chain this paper contributes to the literature that empirically investigates the bullwhip effect by providing new evidence regarding its prevalence and magnitude in contrast to previous work we use a two echelon approach which allows us to observe variations at both the upstream and the downstream sites by drawing on a financial accounting standard regarding information disclosure about major customers we are able to link 5494 buyers and suppliers in the u s between 1976 and 2009 we merge this information with quarterly financial accounting data to form a sample of 14 933 buyer supplier dyad observations we correct for sample selection bias using propensity score matching and estimate the average bullwhip effect in our sample to be 1 90 i e 90 demand variability amplification between echelons a significant bullwhip effect is observed across industries mining manufacturing wholesale and retail and is supported by several robustness checks we investigate and discuss how these results can be generalized beyond our sample

a novel time varying bullwhip effect metric an application to promotional sales abstract bullwhip effect is a problem of paramount importance that reduces competitiveness of supply chains around the world a significant effort is being devoted by both practitioners and academics to understand its causes and to reduce its pernicious consequences nevertheless limited research has been carried out to analyse potential metrics to measure it that typically are summarized in the coefficient of variation ratio of different echelons demand this work proposes a new metric based on a time varying extension of the aforementioned bullwhip effect metric by employing recursive estimation algorithms expressed in the state space framework to provide at each single time period a real time bullwhip effect estimate in order to illustrate the results a case study based on a serially linked supply chain of two echelons from the chemical industry is analysed particularly this metric is employed to analyse the effect of promotional campaigns on the bullwhip effect on a real time fashion the results show that effectively the bullwhip effect is not constant along time but interestingly it is reduced during the promotional periods and it is bigger before and after the promotion takes place

on the stability of supply chains this paper examines the stability of decentralized multistage supply chains under arbitrary demand conditions it looks for intrinsic properties of the inventory replenishment policies that hold for all customer demand processes and for policies with desirable properties it is found that the overall conditions experienced by suppliers several stages removed from the final customer e g the variances of the orders they receive and the inventories they keep depend on the policy much more than on the demand process a policy specific but demand independent upper bound for the order variance amplification factor of any decentralized policy is shown to exist and its formula is presented the bound is always tight for the suppliers at the end of a long chain so that a policy exhibits the bullwhip effect if and only if its bound is greater than 1 a simple necessary condition for bullwhip avoidance is also identified in terms of a policy s gain gain is the marginal change in average inventory induced by a policy when there is a small but sustained change in the demand rate it is shown thatall policies with positive gain produce the bullwhip effect if they do not use future order commitments because manufacturers can reduce costs by operating with positive gain this explains the prevalence of the bullwhip effect a family of commitment based policies that can dynamically maintain any desired inventory level for any demand rate e g achieve positive gain without the bullwhip effect is also presented the family includes just in time strategies as a special case simulation results are used as an illustration

optimization of a vendor managed inventory supply chain with guaranteed stability and robustness abstract in this work we address the steady state optimization of a supply chain model that belongs to the class of vendor managed inventory automatic pipeline inventory and order based production control systems vmi apiobpcs the supply chain is optimized with the so called normal vector method which has specifically been developed for the economic optimization of uncertain dynamical systems with constraints on dynamics we demonstrate that the normal vector method provides robust optimal points of operation for a number of scenarios since the method strictly distinguishes economic optimality which is treated as the optimization objective from dynamical requirements which are incorporate by appropriate constraints it provides a measure for the cost of stability and robustness as a desired side effect

the bullwhip effect in capacitated supply chains with consideration for product life cycle aspects abstract this paper presents an analysis of the bullwhip effect and net stock amplification in a three echelon supply chain considering step changes in the production rates during a product s life cycle demand the analysis is focused around highly complex and engineered products e g automobiles that have relatively long production life cycles and require significant capital investment in manufacturing using a simulation approach we analyze three stages of the product life cycle including low volumes during product introduction peak demand and eventual decline toward the end of the life cycle parts of the simulation model have been adopted by a major north american automotive oem as part of a scenario analysis tool for strategic supply network design and analysis the simulation results show that performance of a system as a whole deteriorates when there is a step change in the life cycle demand while restriction in production capacity does not significantly impact the bullwhip effect it increases the net stock amplification significantly for the supply chain setting under consideration furthermore a number of important managerial insights are presented based on sensitivity analysis of interaction effect of capacity constraints with other supply chain parameters

the effect of emission permit trading with banking on firm s production inventory strategies abstract we investigate the effect of tradable emission permits with banking on the production inventory strategy of a firm in this paper the basis of the work is the well known arrow karlin dynamic production inventory model in which the inventory holding costs are linear and production costs are non decreasing and convex functions of the production level the cost of environmental protection is taken into account in the model we assume there is an emission trading program with which firms are able to purchase their emission rights or sell them and the rights are allowed to be deposited in intertemporal trading we compare the optimal production inventory strategies of this paper with those without emission permits

the short and long run determinants of less educated immigrant flows into u s states we use a gravity model of migration and alternative estimation strategies to analyze how income differentials affect the flow of immigrants into u s states using annual data from the american community survey we add to existing literature by decomposing income differentials into short and long term components and by focusing on newly arrived less educated immigrants between 2000 and 2009 our sample is unique in that the vast majority of our observations take zero values models that include observations with zero flow values find that recent male immigrants respond to differences in short term gdp fluctuations between origin countries and u s states and perhaps to long term trend gdp differences as well more specifically gdp fluctuations pull less educated male immigrants into certain u s states whereas gdp trends push less educated male immigrants out of their countries of origin effects for less educated women are less robust as gdp coefficients tend to be much smaller than for men

on bullwhip in supply chains historical review present practice and expected future impact abstract demand amplification or bullwhip as it is now called is not a new phenomenon since evidence of its existence has been recorded at least as far back as the start of the 20th century and is well known to economists yet industry worldwide still has to cope with bullwhip measured not just in terms of the 2 1 amplification which is frequently quoted but sometimes it is as high as 20 1 from end to end in the supply chain this can be very costly in terms of capacity on costs and stock out costs on the upswing and stockholding and obsolescence costs on the downswing in this paper we have identified 10 published causes of bullwhip all of which are capable of elimination by re engineering the supply chain we offer evidence on the present health of a family of supply chains and pinpoint much good practice this is in anticipation that such excellence will become normative in the near future as the learning experience gathers momentum and provided that human factors are properly addressed

tackling the european migration problem this paper will begin by examining the historical pattern of migration and the empirical dimension of western europes migration problem a next step examines the labor market issues and impacts on natives as western europe perceives them the paper concludes with a discussion of policy issues and options excerpt

tradable permits and production inventory strategies of the firm abstract the paper deals with the effect of introduction of tradable permits on the production inventory strategy of a firm the basic model of arrow and karlin 1958 production over time with increasing marginal costs in arrow k j karlin s scarf h eds studies in the mathematical theory of inventory and production stanford university press stanford pp 61 69 assumes that the firm minimizes the sum of linear holding and convex production costs these costs depend explicitly on time after introducing emission trading the cost function will contain linear emission procurement selling cost we compare two optimal production inventory strategies of a firm to examine changes of optimal strategies the first strategy is the optimal solution of the arrow karlin model then we analyze this model extended with costs of tradable permits

measure of bullwhip effect in supply chains with autoregressive demand process abstract in supply chain management one of the most critical problems which require a lot of effort to deal with is how to quantify and alleviate the impact of bullwhip effect the phenomenon in which information on demand is distorted while moving upstream although it is well established that demand forecast lead time order batching shortage gaming and price fluctuation are the main sources that lead to the bullwhip effect the problem of quantifying bullwhip effect still remain unsolved in many situations due to the complex nature of the problem in this research a measure of bullwhip effect will be developed for a simple two stage supply chain that includes only one retailer and one supplier in the environment where the retailer employs base stock policy for their inventory and demand forecast is performed through the first order autoregressive model ar 1 the effect of autoregressive coefficient and lead time on this measure will then be investigated

the effect of replenishment policies on the bullwhip effect a transfer function approach an important phenomenon in supply chain management known as the bullwhip effect suggests that demand variability increases as one moves up a supply chain this paper examines the influence of different replenishment policies on the occurrence of the bullwhip effect the paper demonstrates that certain replenishment policies can in themselves be inducers of the bullwhip effect while others inherently lower demand variability the main causes of increase in variability are projections of future demand expectations which result in over exaggerated responses to changes in demand we suggest that through appropriate selection and use of certain replenishment rules the bullwhip effect can be avoided subsequently allowing supply chain management costs to be lowered

a pragmatic approach to the design of bullwhip controllers it is well known that forecasting mechanisms can greatly increase bullwhip demand variance amplification of orders as processed by both human and algorithmic decision makers this paper is concerned with the application of the well established apiobpcs decision support system a variant of the order up to rule in such circumstances it has two feedback controls based on the inventory and the orders in pipeline respectively with gains set equal according to the deziel eilon rule there is one feed forward control based on exponential forecasting although this is not a restriction on the application of this system we consider the pragmatic role of apiobpcs in the situation where the echelon decision maker may be handling a wide range of sku s in a non altruistic environment where upmarket information may either be withheld or simply unavailable under such circumstances it has been established via site based studies that the decision makers output the orders reflect a wide range of strategies or maybe ignorance three strategies may be regarded as appropriate i e pass orders along demand smoothing and level scheduling depending on context apiobpcs can be adapted to each of these modus operandi in the first case with the added capability of smoothing the sharp edges with a modicum of inventory variation and in the last case with the advantage of built in trend detection players in non altruistic supply chains must be able to cope with added uncertainties due to lead time variations we show that apiobpcs may be well matched to such situations and is hence copable as well as capable the paper includes recommended parameter settings according to desired decision making policies

managing the order pipeline to reduce supply chain volatility the bullwhip effect in particular and supply chain volatility in general has been the subject of much analytical and empirical investigation by researchers one goal of this work has been to determine supply chain designs and policies that minimize volatility using a system dynamics approach we use three distinct supply chain volatility metrics to compare the ability of two alternative pipeline inventory management policies to respond to a demand shock the results indicate that no one policy dominates on all three metrics of supply chain volatility a simplistic static pipeline policy minimizes the bullwhip effect and lessens the likelihood of on hand inventory oscillations while a more sophisticated dynamic pipeline policy may converge more rapidly to the new equilibrium in addition simulation results suggest that the dynamic policy provides better customer service through fewer stockouts and backorders

measuring and avoiding the bullwhip effect a control theoretic approach an important contributory factor to the bullwhip effect i e the variance amplification of order quantities observed in supply chains is the replenishment rule used by supply chain members first the bullwhip effect induced by the use of different forecasting methods in order up to replenishment policies is analysed variance amplification is quantified and we prove that the bullwhip effect is guaranteed in the order up to model irrespective of the forecasting method used thus when production is inflexible and significant costs are incurred by frequently switching production quantities up and down order up to policies may no longer be desirable or even achievable in the second part of the paper a general decision rule is introduced that avoids variance amplification and succeeds in generating smooth ordering patterns even when demand has to be forecasted the methodology is based on control systems engineering and allows important insights to be gained about the dynamic behaviour of replenishment rules

forecasting and inventory performance in a two stage supply chain with arima 0 1 1 demand theory and empirical analysis the arima 0 1 1 demand model has been analysed extensively by researchers and used widely by forecasting practitioners due to its attractive theoretical properties and empirical evidence in its support however no empirical investigations have been conducted in the academic literature to analyse demand forecasting and inventory performance under such a demand model in this paper we consider a supply chain formed by a manufacturer and a retailer facing an arima 0 1 1 demand process the relationship between the forecasting accuracy and inventory performance is analysed along with an investigation on the potential benefits of forecast information sharing between the retailer and the manufacturer results are obtained analytically but also empirically by means of experimentation with the sales data related to 329 stock keeping units skus from a major european superstore our analysis contributes towards the development of the current state of knowledge in the areas of inventory forecasting and forecast information sharing and offers insights that should be valuable from the practitioner perspective