international consumption risk sharing this paper formally examines the implications of international consumption risk sharing for a panel of industrialized countries we theoretically derive the international consumption insurance proposition in a simple setup and show how to modify it in more complicated models we analyze the implications of the theory for pairs of countries and find that aggregate domestic consumption is almost completely insured against idiosyncratic real demographic fiscal and monetary shocks over short cycles but that it covaries with these variables over medium and long cycles the cross equation restrictions imposed by the theory are rejected the policy implications are discussed

efficient mechanisms for bilateral trading we consider bargaining problems between one buyer and one seller for a single object the seller s valuation and the buyer s valuation for the object are assumed to be independent random variables and each individual s valuation is unknown to the other we characterize the set of allocation mechanisms that are bayesian incentive compatible and individually rational and show the general impossibility of ex post efficient mechanisms without outside subsidies for a wide class of problems we show how to compute mechanisms that maximize expected total gains from trade and mechanisms that can maximize a broker s expected profit journal of economic literature classification number 026

perishable inventory theory a review this paper reviews the relevant literature on the problem of determining suitable ordering policies for both fixed life perishable inventory and inventory subject to continuous exponential decay we consider both deterministic and stochastic demand for single and multiple products both optimal and sub optimal order policies are discussed in addition a brief review of the application of these models to blood bank management is included the review concludes with a discussion of some of the interesting open research questions in the area

inventory models with managerial policy independent of demand abstract this paper is an extension of two papers the first of these published in european journal of operational research 2007 112 120 is by deng et al 2007 and concerns inventory models for deteriorating items with ramp type demand the second published in computer industrial engineering 2009 1296 1300 is by cheng and wang 2009 and concerns inventory models for deteriorating items with trapezoidal type demand the purpose of this paper is threefold first this paper will show that the optimal solution is independent of the demand considered in the two previous papers second several replenishment cycles were considered during the finite time horizon to balance the set up cost with the sum of the deteriorated cost holding cost and shortage cost third this paper will examine the same numerical example in cheng and wang 2009 to show that this new approach will result in the saving of 84 39

risk sharing by households within and across regions and industries abstract cochrane 1991 journal of political economy 99 957 976 and mace 1991 journal of political economy 99 928 956 test if risk sharing across households is complete in the sense that household consumption moves one for one with aggregate consumption in their studies the source of income risk is idiosyncratic and agents can share risk across the entire economy using a sample of households from the panel study on income dynamics psid we explore whether households share the risk associated with their industries and regions across households in other regions and industries we find that a large fraction of risk faced by households is not shared across regions and industries

pricing and lot sizing polices for perishable goods when the demand depends on selling price displayed stocks and expiration date abstract price is a major factor on the demand based on marketing and economic theory in addition the demand for perishable products also depends on its freshness moreover it is a well known fact that increasing stock display e g fresh fruits vegetables baked goods may encourage consumers to purchase more this paper first proposes an inventory model that stipulates the demand explicitly in a multivariate function of price freshness and displayed stocks it may be profitable to have a closeout sale at a markdown price and always keep on hand displayed stocks fresh and plentiful if the demand is freshness and stock dependent hence the traditional assumption of zero ending inventories is relaxed to a non zero ending inventory as a result the objective is to determine three decision variables i e unit price cycle time and ending inventory level in order to maximize the total profit then it is demonstrated that the total profit is strictly pseudo concave in those three decision variables which reduces the search for solutions to a unique local maximum finally numerical examples to illustrate the theoretical results and to highlight managerial insights are presented

pricing and lot sizing decisions for perishable goods when demand depends on selling price reference price product freshness and displayed stocks abstract price is an important factor affecting demand rate based on economic and marketing theory in addition today s health conscious consumers prefer a product further from its expiration date because it is fresher and can be stored longer furthermore a large display of goods in a supermarket induces customers to buy more due to its visibility variety and seasonality as a result we develop a joint pricing and lot sizing model for retailers selling perishable products in which the demand depends on not only the selling price and reference price but also the product freshness linked to expiration date and displayed stock level we then formulate the problem as a deterministic model in which the retailer determines the optimal selling prices and ending inventory levels to maximize the discounted total profit furthermore we discuss the retailer s optimal decisions under two scenarios of demand behavior loss neutrality and loss aversion our theoretical analysis shows that the optimal pricing and ending inventory level strategies are both monotonic in time and the equilibrium of the system is unique for these two scenarios of demand behavior finally a set of structural properties and sensitivity analysis is also developed to characterize the impacts of model parameters on the optimal decisions

international risk sharing in the short run and in the long run international risk sharing has far reaching implications both for economic policy and for basic research in economics when countries do not share consumption risk individuals experience consumption fluctuations that are undesirable and possibly unnecessary we investigate bilateral risk sharing at short vs long horizons we find substantial cross country consumption correlations at trend and business cycle frequencies correlations are particularly high within europe prior research focused on first difference correlations which are typically quite low we argue that this reflects measurement error at all horizons we find that consumption correlations are not significantly different from output correlations implying a lack of deliberate consumption risk sharing le partage international du risque a de grandes implications a la fois pour la politique economique et pour la recherche economique de base quand des pays ne partagent pas les risques de consommation les individus font l experience de fluctuations de consommation indesirables et possiblement non necessaires on examine le partage de risque bilateral a court et a long terme on decouvre des correlations entre pays tant au niveau des tendances que des frequences du cycle d affaires ces correlations sont particulierement elevees en europe des travaux anterieurs se sont concentres sur les correlations entre premieres differences qui sont typiquement assez faibles on suggere que ces resultats refletent une erreur de mesure pour tous les horizons temporels on decouvre que les correlations de consommation ne different pas significativement des correlations de production ce qui implique un manque de partage de risque delibere au niveau de la consommation

what macroeconomic risks are not shared by international investors adopting an asset market view of international risk sharing we identify various sources of macroeconomic risk faced by international investors using a structural vector autoregression model we find that most of the risks of exogenous financial market shocks are shared by international investors through the existing asset markets however other macroeconomic risks such as those associatedwith exogenousshocks to consumption growth inflationandmonetarypolicies arenot fullysharedacrosscountries this finding helps us understand the apparently contradicting perceptions of international risk sharing generated by the analysis of asset market returns versus that of aggregate consumption growth across countries jel codes e44 f31 g12

optimal control of a single stage production system subject to random process shifts we consider a single stage production system with poisson demand and exponential processing times after producing a good item the production process can shift to an out of control state with a given probability and start producing bad items the state of the process is known only when the next stage or customer receives the item once an out of control process is detected process correction is instantaneous customers arriving to an empty system get backlogged in this framework we examine fifo first in first out and lifo last in first out issuing policies the objective is to minimize the total expected discounted or average costs over an infinite time horizon we characterize the structure of the optimal production policy for fifo and lifo show that lifo is better than fifo and in general better than a large class of issuing policies a numerical example illustrates that savings up to 20 percent can be obtained from using lifo over fifo we also derive conditions under which maintaining z

does resorting to online dispute resolution promote agreements experimental evidence abstract this paper presents an experiment performed to test the properties of an innovative bargaining mechanism called automated negotiation used to resolve disputes arising from internet based transactions the main result shows that the settlement rule tends to chill bargaining as it creates incentives for individuals to misrepresent their true valuations which implies that automated negotiation is not able to promote agreements however this perverse effect depends strongly on the conflict situation when the threat that a disagreement occurs is more credible the strategic effect is reduced since defendants are more interested in maximizing the efficiency of a settlement than their own expected profit the implications of these results are then used to discuss the potential role of public regulation and reputation mechanisms in cyberspace

an eoq model for perishable products with fixed shelf life under stochastic demand conditions abstract the paper presents a mathematical stochastic model for perishable open dating foods including shortage and outdating costs the demand fluctuations have been taken into account modeling them through a normal distribution and their impact on the storage time has been studied considering the stochastic nature of such a parameter in turn the quantification of perished products has been also addressed determining the probability for a product of remaining in stock beyond the end of its shelf life on the basis of such premises the optimal set of parameters that minimize the total unit cost has been determined a numerical application and a sensitivity analysis show the practical applicability of the proposed model in the context of warehouse management underlining managerial insights

optimal discounting and replenishment policies for perishable products abstract we consider a retailer selling a perishable product with short shelf life and uncertain demand facing these key decisions a whether to discount old er items b how much discount to offer and c what should be the replenishment policy in order to better understand the impact of consumer behavior and shelf life on these decisions we consider four models in model a the product has a shelf life of two periods and the retailer decides whether or not to offer a discount the amount of discount is exogenous and assumed to be large enough so that all the customers prefer the old product to the new one when a discount is offered based on several numerical examples we find that a threshold discounting policy in which a discount is offered if and only if the inventory of old product is below a threshold is optimal in model b the retailer also decides how much discount to offer model c extends model b and considers a new pool of customers who are willing to purchase from the retailer when a discount is offered in both models b and c the product has a shelf life of two periods while model d explores what happens with longer shelf life we analyze and compare these models to present different managerial insights

incentive problems and the pattern of international risk sharing abstract this paper analyzes the implications of moral hazard and a lack of contract enforcement for risk sharing across countries and regions we demonstrate that both incentive problems can considerably restrict efficient risk sharing however we show that the cross sectional risk sharing component is much more affected than the intertemporal component we argue that this may help to explain several stylized facts of international risk sharing such as the low degree of insurance against permanent shocks

efficient inventory control for imperfect quality items in this paper we present a general eoq model for items that are subject to inspection for imperfect quality each lot that is delivered to the sorting facility undertakes a 100 per cent screening and the percentage of defective items per lot reduces according to a learning curve the generality of the model is viewed as important both from an academic and practitioner perspective the mathematical formulation considers arbitrary functions of time that allow the decision maker to assess the consequences of a diverse range of strategies by employing a single inventory model a rigorous methodology is utilised to show that the solution is a unique and global optimal and a general step by step solution procedure is presented for continuous intra cycle periodic review applications the value of the temperature history and flow time through the supply chain is also used to determine an efficient policy furthermore coordination mechanisms that may affect the supplier and the retailer are explored to improve inventory control at both echelons the paper provides illustrative examples that demonstrate the application of the theoretical model in different settings and lead to the generation of interesting managerial insights

dynamic economic lot size model with perishable inventory this paper considers an economic lot size els model for perishable products where an inventory stock s deterioration rate and its carrying cost in each period depend on the age of the stock we discuss situations where the traditional els models are not applicable and propose a new model with general concave production and inventory cost functions we explore the structural properties of the optimal solutions and use them to develop a dynamic programming algorithm which solves the problem in polynomial time we also consider special cases of the general model which are solvable with reduced computational complexities

approximation algorithms for perishable inventory systems we develop the first approximation algorithms with worst case performance guarantees for periodic review perishable inventory systems with general product lifetime for both backlogging and lost sales models the demand process can be nonstationary and correlated over time capturing such features as demand seasonality and forecast updates the optimal control policy for such systems is notoriously complicated thus finding effective heuristic policies is of practical importance in this paper we construct a computationally efficient inventory control policy called the proportional balancing policy for systems with an arbitrarily correlated demand process and show that it has a worst case performance guarantee less than 3 in addition when the demands are independent and stochastically nondecreasing over time we propose another policy called the dual balancing policy which admits a worst case performance guarantee of 2 we demonstrate through an extensive numerical study that both policies perform consistently close to optimal

an inventory model with generalized type demand deterioration and backorder rates abstract this study is motivated by the paper of skouri et al skouri konstantaras papachristos ganas european journal of operational research 192 1 2009 79 92 we extend their inventory model from ramp type demand rate and weibull deterioration rate to arbitrary demand rate and arbitrary deterioration rate in the consideration of partial backorder we demonstrate that the optimal solution is actually independent of demand that is for a finite time horizon any attempt at tackling targeted inventory models under ramp type or any other types of the demand becomes redundant our analytical approach dramatically simplifies the solution procedure

bad and good news about the sealed bid mechanism some experimental results this paper surveys a set of experiments conducted by roy radner and myself 1989 and peter linhart radner and myself 1989a b all of which were conducted to investigate the properties of the sealed bid mechanism a mechanism used to structure bargaining under situations of incomplete information what we find is both bad news and good news for the mechanism the bad news is that the behavior of subjects seems quite sensitive to the parameters of the prior distribution of types used and the number of rounds over which the experiment is run as such prior distributions become more skewed in a sense to be defined below and the number of rounds in the experiment are increased to 75 bidder behavior becomes less linear such movements have a regular pattern however and this phenomenon is remarkably consistent the good news is that such behavioral shifts do not seem to interfere with the efficiency of the mechanism this is of course important for the acceptance of the mechanism in the real world since if efficiency were to change dramatically as we change the parameters of the environment adoption would have to proceed on a case by case basis the fact that our results imply robustness of efficiencies indicates that at least on a practical level the sealed bid mechanism may be a viable way to structure bargaining in many large scale economic organizations i the sealed bid mechanism

trading complex assets we perform an experimental study of complexity to assess its eect on trading behavior price volatility liquidity and trade eciency subjects were asked to deduce the value of a particular asset from information they were given about the composition and price of several portfolios following that subjects traded with each other anonymously in a well dened simple bargaining process portfolio composition ranged from requiring simple analysis to more complicated computation in order to deduce the value of the asset complexity altered subjects bidding strategies decreased liquidity increased price volatility and decreased trade eciency however in follow up experiments we show that uncertainty over private values does not lead to the same changes in trading behavior therefore while complexity induces estimation errors and higher uncertainty this is not what drives our results

the information advantage in two person bargaining with incomplete information abstract the sealed bid k double auction is a mechanism used to structure bilateral bargaining under two sided incomplete information in the process of testing whether or not the observed bid and ask functions are in agreement with the bayesian linear equilibrium solution under asymmetric information conditions we find a strong information disparity effect the trader favored by the information disparity whether buyer or seller receives a significantly larger share of the realized gains from trade than that predicted by the theory a reinforcement based learning model is formulated and tested it accounts successfully for most of the variability in the round to round individual decisions

international business cycles in theory and in practice this paper investigates whether multi country international business models can account for international comovements in the oecd there are substantial positive comovements between many output components between levels of employment and between total factor productivities the standard international business cycle model is not consistent with these comovements except for consumption levels the model implies either negative or very low comovements this is a robust feature of the theoretical models independently of specific parameter values one interesting finding is that a more general specification of the technology shock processes lead to substantial comovements but at the cost of another deficiency

a production inventory model in an imperfect production process abstract the paper develops a model to determine the optimal product reliability and production rate that achieves the biggest total integrated profit for an imperfect manufacturing process the basic assumption of the classical economic manufacturing quantity emq model is that all manufacturing items are of perfect quality the assumption is not true in practice most of the production system produces perfect and imperfect quality items in some cases the imperfect quality non conforming items are reworked at a cost to restore its quality to the original one rework cost may be reduced by improvements in product reliability i e decreasing in product reliability parameter lower value of product reliability parameter results in increase development cost of production and also smaller quantity of nonconforming products the unit production cost is a function of product reliability parameter and production rate as a result higher development cost increases unit production cost the problem of optimal planning work and rework processes belongs to the broad field of production inventory model which deals with all kinds of reuse processes in supply chains these processes aim to recover defective product items in such a way that they meet the quality level of good item the benefits from imperfect quality items are regaining the material and value added on defective items and improving the environment protection in this point of view a model is introduced here to guide a firm industry in addressing variable product reliability factor variable unit production cost and dynamic production rate for time varying demand the paper provides an optimal control formulation of the problem and develops necessary and sufficient conditions for optimality of the dynamic variables in this purpose the euler lagrange method is used to obtain optimal solutions for product reliability parameter and dynamic production rate finally numerical examples are given to illustrate the proposed model

an algorithm to determine the eoq for deteriorating items with shortage and a linear trend in demand abstract in 1991 professors goswami and chaudhuri considered the inventory replenishment policy over a fixed planning period for a deteriorating item having a deterministic demand pattern with a linear trend and shortages basically they concentrated on the establishment of the inventory model but did not present a concrete algorithm to solve it this paper complements the shortcoming of goswami and chaudhuri s paper we first show that the total cost function of goswami and chaudhuri is convex subsequently with the convexity an algorithm to determine the number of reorders the interval between two successive reorders and the shortage intervals over a finite time horizon in an optimal manner is developed many numerical examples illustrate how the algorithm works

blood platelet inventory management with protection levels abstract we consider a discrete time inventory system for a perishable product where demand exists for product of different ages an example of such a product is blood platelets in addition to the classical costs for inventory holding outdating and shortage our model includes substitution mismatch costs incurred when a demand for a certain aged item is satisfied by a different aged item we propose a simple inventory replenishment and allocation heuristic to minimize the expected total cost over an infinite time horizon in our heuristic inventory of the newest items is replenished in fixed quantities and the newest items are protected for future use by limiting some substitutions when making allocation decisions according to a critical level policy we model our problem as a markov decision process mdp derive the costs of our heuristic policy and computationally compare this policy to extant near optimal policies in the literature our extensive computational study shows that our policy leads to superior performance compared to existing heuristics in the literature particularly when supplies are limited

on an inventory model with deteriorating items and decreasing time varying demand and shortages in this paper we present an optimal procedure for finding the replenishment schedule for an inventory system with shortages in which items deteriorate at a constant rate and demand rates are decreasing over a known and finite planning horizon a numerical example is presented to illustrate the procedure

integrating deterioration and lifetime constraints in production and supply chain planning a survey abstract items with short lifetimes that are subject to deterioration are important in the business world research has a long tradition in integrating deterioration and value loss effects into mathematical models for inventory planning and control where such effects are understood as a general loss or shrinkage of inventory however there has been little work in the modeling of lifetime restrictions of items to prevent wastage and disposals especially in a dynamic planning context globalization and other trends extend the consideration of single companies to whole supply chains implying increased coordination and information needs this is important as planning decisions impact lead times and thus the quality of items in the whole supply chain products that exceed their useful lifetime can impose high costs due to inventory loss or the need to rework them this implies increased utilization of scarce resources e g machine time metals and or energy thereby increasing co 2 levels we survey the state of the art regarding depreciation effects and the modeling of lifetime constraints as well as a classification of models following business planning functions of the value chain a critical evaluation of approaches and their limitations is provided highlighting directions for future research

optimal order policy for deteriorating items with inflation induced demand abstract this paper presents the optimal inventory replenishment policy of deteriorating items under inflationary conditions using a discounted cash flow dcf approach over a finite planning horizon a dcf approach permits a proper recognition of the financial implication of the opportunity cost and out of pocket costs in inventory analysis it also permits an explicit recognition of the exact timing of cash flows associated with an inventory system the demand rate is assumed to be a function of inflation shortages are allowed and completely backlogged optimal solution for the proposed model is derived and the effects of deterioration and inflation on the optimal inventory replenishment policy are studied with the help of numerical example

review of inventory systems with deterioration since 2001 abstract this paper presents an up to date review of the advances made in the field of inventory control of perishable items deteriorating inventory the last extensive review on this topic dates back to 2001 goyal s k and giri b c recent trends in modeling of deteriorating inventory european journal of operational research 134 1 16 since then over two hundred articles on this subject have been published in the major journals on inventory control indicating the need for a new review we use the classification of goyal and giri based on shelf life characteristics and demand characteristics contributions are highlighted by discussing main system characteristics including price discounts backordering or lost sales single or multiple items one or two warehouses single or multi echelon average cost or discounted cash flow and payment delay

consumption risk sharing in china this paper empirically examines the degree of regional consumption risk sharing in china it finds that less risk sharing is taking place across chinese provinces than across us states and canadian provinces although its extent across the latter is somewhat higher than across the national boundaries of industrial countries specifically about half of the fitted annual variation in provincial consumption growth is common to all chinese provinces compared with more than two thirds less than one third in the case of us states and canadian provinces g 7 countries my estimates reveal that chinese households would be willing to pay dearly to insure their consumption against idiosyncratic shocks

bargaining under incomplete information this paper presents and analyzes a bargaining model of bilateral monopoly under uncertainty under the bargaining rule proposed the buyer and the seller each submit sealed offers that determine whether the good in question is sold and the transfer price the nash equilibrium solution of this bargaining game implies an offer strategy of each party that is monotonic in its own reservation price and depends on its assessment of the opponent s reservation price issues of relative bargaining advantage and efficiency are examined for a number of special cases finally we discuss the appropriateness of the nash solution concept

the newsvendor problem in a global market optimal centralized and decentralized control policies for a two market stochastic inventory system the global markets of today offer to the style goods producer more selling opportunities and pose new challenges in production planning and coordination from a production management standpoint the opportunity to exploit the difference in timing of the selling season of geographically dispersed markets for style goods is important for improving the firm s profitability in this paper we examine the above issue with an insightful model of a producer of style goods selling the goods to two markets a primary and a secondary market with nonoverlapping selling seasons we refer to this problem as the global newsvendor problem for the above two market stochastic inventory systems we first develop optimal centralized control policies then we demonstrate the suboptimality of decentralized production control policies with the production centers at each market treated as independent profit centers and a constant transfer price being used to coordinate their production we propose as an effective alternative a decentralized production control structure with a nonlinear pricing scheme for production coordination among centers administered through an intermediate organizational unit in our modeling we explicitly consider the effects of exchange rate uncertainty on the production planning decisions

eoq models for continuously deteriorating products using linear and exponential penalty costs abstract we present eoq models for perishable products which consider continuous deterioration of the utility of a product and introduce an exponential penalty cost function as a measurement of the utility deterioration the approach proposed is simple and can be used to obtain easily the closed forms of the economic order quantities which have not previously been derived these forms describe the effect of the penalty cost clearly and are a natural extension of economic order quantities for non perishable products our results are shown to be consistent with reported eoq models with exponential decay but derived more elaborately our approach has the added advantage that it can be easily extended to the economic lot scheduling problem for multi item perishable products

international dynamic risk sharing in this paper we examine the implications of international risk sharing among a set of countries in the presence of market frictions which complicate the instantaneous adjustment to the first order conditions we suggest approximating the consumption streams of countries belonging to the risk sharing coalition in terms of a disequilibrium dynamic model embodying forward looking adjustment econometric methods for estimating and testing the model are discussed empirical analysis of a set of core european countries suggests that once preference parameters are allowed to vary across countries we are able to identify a group of nations that share risks against idiosyncratic permanent income shocks the equilibrium position however is reached after a long adjustment period copyright 2008 john wiley sons ltd

integrated supply chain management for perishable products dynamics and oligopolistic competition perspectives with application to pharmaceuticals abstract we propose an integrated supply chain management framework that allows us to explicitly consider the impact of product perishability on a broad scale that includes manufacturers distribution centers wholesalers and demand markets the framework proposed herein also makes it possible to consider the oligopolistic competition across wholesalers that drives price and demand fluctuations furthermore the supply chain decision rules are derived from necessary conditions in the framework the inclusion of such salient features allows the framework to generate outcomes that suggest realistic managerial insights we provide a numerical example in which two multi national pharmaceutical firms producing a homogeneous medicinal drug and four oligopolistic wholesalers are considered

taxes and international risk sharing abstract we extend a standard model of international risk sharing to include an empirically plausible distortion taxes the tax inclusive theory implies even under full risk sharing a predictable relationship between consumption growth and the consumption and capital income tax rates both within and across countries we find strong empirical evidence in favor of this relationship while idiosyncratic output fluctuations account for substantially more of cross country consumption growth variability than do taxes trends in tax differentials are found to be informative about the dynamic evolution of international risk sharing in particular adjusting for capital taxes reveals a marked improvement in risk sharing over the last three decades that is absent in baseline measures this improvement has been driven by the convergence of average tax rates on capital income across oecd countries toward the united states average capital tax rate

international risk sharing and european monetary unification abstract we explore income and consumption smoothing patterns among european community ec countries and among oecd countries during the period 1966 90 we find that for oecd as well as for ec countries about 40 percent of shocks to gdp are smoothed at the one year frequency with about half the smoothing achieved through national government budget deficits and half by corporate saving at the three year differencing frequency only 25 percent of shocks to gdp are smoothed mainly via government lending and borrowing in the absence of alternative income and consumption smoothing mechanisms the restrictions on budget deficits imposed by the maastricht treaty should be relaxed to allow governments to run large temporary deficits in response to output shocks

incomplete intertemporal consumption smoothing and incomplete risk sharing this paper develops a method to estimate jointly the degree of intertemporal consumption smoothing and the degree of inter regional risk sharing the empirical results for the u s states and oecd and eu countries suggest that i regardless of the assumption on the degree of intertemporal consumption smoothing the degree of risk sharing within a country is larger than across countries ii the degree of intertemporal consumption smoothing within a country is also larger than across countries and iii the difference between the degree of intertemporal consumption smoothing within u s states and across oecd and eu countries is as large as the difference between the degree of risk sharing contrary to the findings of some past studies

order variability in perishable product supply chains abstract empirical research has shown that the degree of order variability in supply chains is significantly influenced by product and industry specific factors this paper analyzes the impact of perishability on order variability and the bullwhip effect in supply chains we decompose the ordering process of a retailer into a sales and an outdating process and quantify their short and long term variability and correlation we find differences to non perishable product supply chains driven by the impact of the inventory depletion policy stock out management and retailers service level requirement these three factors significantly affect the retailer s order variability and thus the decision making process and the profitability of the upstream supply stage for the majority of instances the perishable nature of a product results in the ordering process having a lower variability than the demand process only when inventory depletion is dominated by last in first out in high service level environments variability amplification can be observed we propose a dynamic ordering policy for the upstream supply stage taking into account negative correlation of retailer orders between periods this dynamic policy may lead to substantial performance improvements in a sensitivity analysis we investigate the impact of shelf life lead time and demand correlation

understanding the persistence properties of international macroeconomic aggregates in this paper the ability of a two country model of growth and cycles is evaluated to explain the persistence properties of output and consumption across countries simulated output and consumption levels replicate the observed appearance of noncointegration across countries simulated output growth rates however do not explain the observed positive serial correlation of output growth rates the reallocation of resources in response to technology shocks generates a negative serial correlation for output growth rates

an inventory model for deteriorating items with time proportional demand and shortages under inflation and time discounting this paper proposes a generalized dynamic programming model for inventory items with weibull distributed deterioration in this model the demand rate is assumed to be time proportional shortages are allowed and completely backordered and the effects of inflation and time value of money are taken into consideration the solutions of the model determine the optimal replenishment schedule over a finite planning horizon so that the present worth of total cost associated with the inventory system is minimized the proposed model permits variation in both the replenishment intervals and the service levels between order cycles as a result it generates a better solution than other optimization models having fixed order intervals and or fixed service levels the solution procedure is illustrated by two numerical examples and comparison with an existing model is carried out

understanding the backus smith puzzle it s the nominal exchange rate stupid backus kehoe and kydland bkk 1992 showed that if international capital markets are complete consumption growth correlations across countries should be higher than their corresponding output growth correlations in stark contrast to the theory however in actual data the consumption growth correlation is lower than the output growth correlation by assuming trade imperfections due to non traded goods backus and smith 1993 showed that there is an additional impediment that works to lower the consumption growth correlation while backus and smith s argument was successful in partially explaining the low growth correlation puzzle it contributed to generating another puzzle because the data forcefully showed that consumption growth is negatively correlated with the real exchange rate which is a violation of the theory in this paper by decomposing the real exchange rate growth of the oecd countries into the nominal exchange rate growth and the inflation differential we find that nominal exchange rate movements are the main source for the backus smith puzzle we find that the nominal exchange rate moves counter cyclically with consumption movements which is a violation of the risk sharing theory with non traded goods we also find that the violations are more pronounced when nominal exchange rate changes are larger in absolute value in contrast the negative of bilateral inflation differentials is positively correlated with bilateral consumption movements the latter finding is in accordance with the theory furthermore using intranational data for the united states where the nominal exchange rate is constant the backus smith puzzle disappears although complete risk sharing is rejected

modeling an inventory routing problem for perishable products with environmental considerations and demand uncertainty the transition to sustainable food supply chain management has brought new key logistical aims such as reducing food waste and environmental impacts of operations in the supply chain besides the traditional cost minimization objective traditional assumptions of constant distribution costs between nodes unlimited product shelf life and deterministic demand used in the inventory routing problem irp literature restrict the usage of the proposed models in current food logistics systems from this point of view our interest in this study is to enhance the traditional models for the irp to make them more useful for the decision makers in food logistics management therefore we present a multi period irp model that includes truck load dependent and thus route dependent distribution costs for a comprehensive evaluation of co2 emission and fuel consumption perishability and a service level constraint for meeting uncertain demand a case study on the fresh tomato distribution operations of a supermarket chain shows the applicability of the model to a real life problem several variations of the model each differing with respect to the considered aspects are employed to present the benefits of including perishability and explicit fuel consumption concerns in the model the results suggest that the proposed integrated model can achieve significant savings in total cost while satisfying the service level requirements and thus offers better support to decision makers

an application of tournament genetic algorithm in a marketing oriented economic production lot size model for deteriorating items abstract the goal of this research is to discuss an application of tournament genetic algorithm tga for solving an economic production lot size epl model in this model the production rate of the item is finite and it is assumed to be a decision variable the demand rate is also a deterministic function of selling price and the marketing cost the selling price per unit item is determined by a mark up over the unit production cost the deterioration rate at any instant is a linear increasing decreasing function of time partial backlogging shortages are allowed with a variable rate dependent on the length of the waiting time up to the starting of next production this model is formulated as a highly non linear constrained optimization problem to solve this problem a tga with steady state selection whole arithmetic crossover and non uniform mutation has been developed and applied the model has been illustrated with three numerical examples finally sensitivity analyses have been shown graphically to study the variations of the average profit with respect to the different parameters

an economic ordering policy model for deteriorating items with time proportional demand abstract a t i s i inventory policy model for deteriorating items is presented in this paper the model is developed based on the assumptions that 1 demand rate is deterministic and linearly changes with time 2 deterioration rate is constant 3 planning horizon is finite and known and 4 replenishment periods are not equal the model is solved using a dynamic programming method the result is applicable to the case where the demand is either increasing or decreasing a numerical example is provided to illustrate the model and solution procedure

an approximation to the continuous review inventory model with perishable items and lead times a continuous review perishable inventory model based on approximations to the expected outdating the expected shortage quantity and the expected inventory level is developed to determine a best q r ordering policy under a positive order leadtime when the total expected average cost per unit time is minimized the approximation method is simple and verified by a comparison with the weiss model the results reveal that the mean absolute deviation from the optimal total expected average cost per unit time is only 0 58 this paper also compares the proposed model to the conventional model with no perishability a value is given to the item lifetime indicating when an approximate answer approaches closely to the conventional ordering policy finally a simulation model written in simscript ii 5 is used to validate the approximate results

dynamic risksharing in the united states and europe abstract we use a panel var model to improve upon the existing methodologies to analyze interregional risksharing and consumption smoothing channels first we endogenize the output process within a more general multi equation framework capturing the dynamic feedback between output and various smoothing channels second in line with dynamic general equilibrium open economy models of risksharing we exploit impulse response functions to trace the role of each smoothing channel over time in the presence of different structural shocks temporary vs permanent and output vs smoothing channels in the application to the us and oecd countries we find different dynamic properties of different smoothing channels we compare our results with the predictions of standard risksharing and consumption theories and tackle some of the puzzles in the literature such as the international risksharing puzzle and the consumption output correlation puzzle we are also able to address such policy issues as whether fiscal stabilizers have been substitutes or complements for financial market diversification activities and whether further financial market integration is likely to provide countries with more shock absorption tools a key result is the strong substitutability between capital and credit smoothing in the us and between fiscal and credit smoothing in the oecd

limited asset market participation and the consumption real exchange rate anomaly under efficient consumption risk sharing as assumed in standard international business cycle models a country s aggregate consumption rises relative to foreign consumption when the country s real exchange rate depreciates yet empirically relative consumption and the real exchange rate are essentially uncorrelated i show that this consumption real exchange rate anomaly can be explained by a simple model in which a subset of households trade in complete financial markets while the remaining households lead hand to mouth htm lives htm behavior also generates greater volatility of the real exchange rate and of net exports which likewise brings the model closer to the data

government consumption and private consumption correlations abstract this paper examines whether the introduction of government consumption expenditure in a standard one good model of the international real business cycle is sufficient to reconcile the theory with the existing pattern of international consumption and output correlations it is shown that the model can account for existing international correlations only under specific assumptions about the size of effect of government expenditure on agents utility or the variability of government expenditure shocks crucial parameters are identified and the sensitivity of the results discussed 1998 elsevier science ltd all rights reserved

inferring shortfall costs and integrating environmental costs into optimal production levels for an all you care to eat food service operation abstract this study examines how optimal food production policies at an all you care to eat aycte facility would change were life cycle cost estimates of embodied co2 included in the disposal costs associated with overproduction in an aim to study production planning possibilities in a situation that places increased emphasis on the environmental impacts of overproduction aycte operations exhibit a lack of revenue associated with each item served since there is no per item lost sales value incurred when demand exceeds supply accordingly the second objective of this research is to present a novel method for estimating shortfall costs in a setting with no marginal revenue per satisfied unit of demand we examine empirical data from aycte operations at the university of missouri s campus dining services cds to infer the per item shortfall costs that are implied by cds management s historical production decisions consistent with cds management s stated aversion to shortfalls we estimate shortfall values which are between 1 6 and 2 7 times larger than the procurement cost and between 30 and over 100 times larger than the disposal cost utilizing published estimates of life cycle co2 and the social cost of carbon we identify a per portion environmental cost we incorporate the environmental costs associated with wasted overproduction and the inferred shortfall cost estimates into a newsvendor model formulation to identify new optimal production levels illustrating this approach with application to a set of food items served by cds we find that optimal production levels are decreased significantly 18 25 for food items with high environmental impacts such as beef and reduced less for foods with less embodied co2

analysis of a sampling control scheme for a perishable inventory system we consider an inventory system in which both the arrival of items and the demand for those items are poisson processes the stored items have two phases of shelf life if the item has not been taken by a demand during the first phase it is inspected with probability q it is removed and with probability p 1 q it is transferred to the second phase the blood bank model inspired this study we compute ergodic limits for the number of items in the system the lost demands and the two types of outdating

an eoq model with ramp type demand rate time dependent deterioration rate unit production cost and shortages an order level inventory system for deteriorating items has been developed with demand rate as a ramp type function of time the finite production rate is proportional to the demand rate and deterioration rate is time proportional the unit production cost is inversely proportional to the demand rate the model with no shortage case in inventory is first solved the inventory shortage is discussed next results are illustrated with two numerical examples for two models along with its sensitivity

variations of order level inventory models for deteriorating items abstract order level inventory models for deteriorating items have been developed and solved with and without shortages the finite production rate is proportional to the demand rate which is time dependent the rate of deterioration also is taken to be time variable illustrative numerical examples are given and significant features of the results are discussed

borrowing constraints and international risk sharing evidence from asymmetric error correction we analyse the adjustment process of consumption growth after disequilibrating output shocks in a sample of organization for economic cooperation and development oecd countries in particular we test the hypothesis that consumption is smoothed to a lesser degree after negative shocks whereas the impact of a positive shock is delayed for a longer period of time our analysis is based on an error correction framework that allows for asymmetric adjustment we find that the mean adjustment lag after a negative shock is significantly shorter than after a positive shock especially since the beginning of the 1980s this result is consistent with the interpretation that borrowing constraints limit the degree to which the impact of negative shocks on consumption can be smoothed

consumption risk sharing in italy this paper analyses the issue of consumption risk sharing in the 20 italian regions during the period 1983 94 the tests proposed allow for regional specific departures from the hypothesis of complete risk sharing and for the existence of non separabilities among groups of commodities empirical evidence suggests the rejection of the hypothesis of complete consumption risk sharing

an optimal production inventory model for deteriorating items with multiple market demand the global markets of today offer more selling opportunities to the deteriorating items manufacturers but also pose new challenges in production and inventory planning from a production management standpoint opportunities to exploit the difference in the timing of the selling season between geographically dispersed markets for deteriorating items are important to improving a firm s profitability in this paper we examined the above issue with an insightful production inventory model of a deteriorating items manufacturer selling goods to multiple markets with different selling seasons we also provided a solution procedure to find the optimal replenishment schedule for raw materials and the optimal production plan for finished products a numerical example was then used to illustrate the model and the solution procedure finally sensitivity analysis of the optimal solution with respect to major parameters was carried out

international risk sharing and commodity prices cole and obstfeld 1991 exposited a classic result where equilibrium movements in the terms of trade could make ex ante risk sharing arrangements unnecessary a unity elasticity of substitution across goods and production specialization this paper extends their model to n countries and m commodities n m here the terms of trade provides insurance against commodity specific shocks not country specific shocks using commodity level production data at the national level and world commodity prices we document significant terms of trade variability and positive responses of nation specific production to terms of trade improvements the endogenous terms of trade insurance mechanism highlighted in co is virtually non existent cole et obstfeld 1991 ont developpe un resultat classique montrant que les mouvements d equilibre dans les termes d echange pouvaient faire l economie d arrangements ex ante pour le partage du risque une elasticite de substitution unitaire entre biens et specialisations dans la production ce texte developpe leur modele pour n pays et m biens n m les termes d echange fournissent l assurance contre les chocs specifiques a certains biens mais non contre les chocs en provenance de certains pays utilisant des donnees de production au niveau des biens au plan national et des prix des biens au niveau mondial on observe une variabilite significative des termes d echange et des reponses positives de la production specifiquement nationale aux ameliorations dans les termes d echange le mecanisme endogene d assurance via les termes d echange mis en lumiere par co est virtuellement non existant

eoq models for perishable items under stock dependent selling rate this paper presents inventory models for perishable items with stock dependent selling rate the selling rate is assumed to be a function of current inventory level and rate of deterioration is taken to be constant under instantaneous replenishment with zero lead time the model incorporates aspects such as complete partial and no backlogging eoq is determined for maximizing the total profit in each of the situations the models developed are illustrated through numerical examples and sensitivity analysis is reported

on the empirics of risk sharing across mena countries in this article we compute the potential welfare gains and the realized gains from risk sharing among middle east and north african mena countries including the oil rich gulf region and the resource scarce economies we find that the overall potential welfare gains across mena countries are positive for all countries under the assumption of full risk sharing the potential welfare gains among the six gulf cooperation council gcc countries are positive even though the magnitudes are smaller compared to those of the rest of the mena region we also quantify the extent of risk sharing for the mena region and show that it is significant for the mena region and its subgroups however we could not find any sign of inter temporal smoothing across the same groups decomposing the aggregate output shocks shows that the extent of risk sharing is significant when only positive output shocks exist across the resource scarce mena economies however we observe that gcc countries share output risks with each oth

risk sharing through capital gains we estimate channels of international risk sharing between european monetary union emu european union and other oecd countries 1992 2007 we focus on risk sharing through savings factor income flows and capital gains risk sharing through factor income and capital gains was close to zero before 1999 but has increased since then risk sharing from capital gains at about 6 is higher than risk sharing from factor income flows for european union countries and oecd countries risk sharing from factor income flows is higher for euro zone countries at 14 reflecting increased international asset and liability holdings in the euro area on examine les canaux de partage international du risque entre l union monetaire europeenne l union europeenne et les autres pays de l ocde 1992 2007 on se concentre sur le partage du risque via les epargnes les flux de revenus des facteurs et les gains de capitaux le partage du risque via les revenus des facteurs et les gains de capitaux a ete presque nul avant 1999 mais s est accru depuis le partage du risque via les gains de capitaux a peu pres 6 est plus grand que le partage du risque via les flux de revenus des facteurs pour les pays de l union europeenne et les pays de l ocde le partage du risque vis les flux de revenus des facteurs est plus eleve pour l euro zone a quelques 14 refletant le fait que les actifs et passifs internationaux detenus dans la zone euro se sont accrus

optimal and heuristic inventory replenishment models for deteriorating items with exponential time varying demand abstract in this paper we present optimal and heuristic procedures for the inventory replenishment problem in which items are deteriorating at a constant rate the demand rates are changing exponentially with time over a known and finite planning horizon we have developed an iterative numerical procedure to find the optimal replenishment schedule the first two heuristics are based on the economic order interval approximation the third heuristic restricts all the replenishment cycles over the planning horizon to be equal over the planning horizon the last three heuristics are extended versions of the silver meal heuristic the least cost approach and the least unit cost heuristic which were used in the inventory literature for the case of discrete time varying demand without deterioration we further assess the cost and computation time effectiveness of the six heuristics the results of a sample of 1440 problems show that the extended least cost approach is the most cost effective

production control in the face of storable raw material random supply and an outside market we study a periodic review production inventory control problem where both the supply of raw material and demand for the finished product are exogenous and random the raw material can be stored for future use can be purchased from or sold to an outside market we study both the lost sales and backlogging cases under both strict convex and linear raw material purchasing selling costs convexity of the purchasing selling cost implies that the more the firm purchases from or sells to the outside market the more expensive or less valuable the raw material becomes for all cases we find the partial characterizations for the optimal policies which all turn out to be very intuitively appealing in particular for each of the linear cost cases the optimal policy degenerates into a combination of two base stock policies one for the raw material inventory and the other for the finished product inventory

risk sharing role of foreign aid in developing countries abstractthe effects of foreign aid on economic growth have been extensively investigated over the past 40 years however even though foreign aid can be a significant source of insurance against do

optimal joint dynamic pricing advertising and inventory control model for perishable items with psychic stock effect abstract in this study a joint pricing advertising and inventory control problem will be investigated for a firm selling perishable products with psychic stock effect the proposed problem is analyzed in the deterministic multi period setting in which demand at each period depends on not only the amount of inventory displayed and advertising goodwill affected by the firm s current and past advertising efforts but also selling price and freshness index the objective is to determine the optimal pricing advertising and psychic stock strategies maximizing the discount total profit over the infinite planning horizon our theoretical results prove that the firm would adopt a static pricing strategy and then demonstrate that the optimal paths of the advertising goodwill and psychic stock can be determined uniquely we also show that the convergence of the advertising goodwill towards its equilibrium is from above or below depending on the relative location of the initial stock of advertising goodwill with respect to the unique equilibrium stock of advertising goodwill moreover a set of structural properties is developed to explore the relationships among the optimal decisions finally the concluding remarks and suggestions will be provided for future studies

a deterministic eoq model with delays in payments and price discount offers abstract it is the purpose of this paper to model the retailer s profit maximizing strategy when confronted with supplier s trade offer of credit and price discount on the purchase of merchandise generally retailers have to face many types of demands for different kinds of goods in real situation retailers have to correlate between the selling price and supplier s trade offer keeping in mind profit maximization strategy in the proposed model all increasing deterministic demands are discussed analytically numerically and graphically in the environment of permissible delay in payment and discount offer to the retailer

coordinating inventory control and pricing strategies for perishable products we analyze a joint pricing and inventory control problem for a perishable product with a fixed lifetime over a finite horizon in each period demand depends on the price of the current period plus an additive random term inventories can be intentionally disposed of and those that reach their lifetime have to be disposed of the objective is to find a joint pricing ordering and disposal policy to maximize the total expected discounted profit over the planning horizon taking into account linear ordering cost inventory holding and backlogging or lost sales penalty cost and disposal cost employing the concept of l concavity we show some monotonicity properties of the optimal policies our results shed new light on perishable inventory management and our approach provides a significantly simpler proof of a classical structural result in the literature moreover we identify bounds on the optimal order up to levels and develop an effective heuristic policy numerical results show that our heuristic policy performs well in both stationary and nonstationary settings finally we show that our approach also applies to models with random lifetimes and inventory rationing models with multiple demand classes

home bias and international risk sharing twin puzzles separated at birth abstract we document that international home bias in debt and equity holdings declined during the period 1993 2003 at the same time as international risk sharing increased using panel data regressions for oecd countries we demonstrate that less home bias is associated with more international risk sharing more generally we show that more financial integration is associated with more risk sharing when we measure financial integration as the ratio of foreign assets to gross domestic product our results indicate that risk sharing and international financial integration are closely related empirical phenomena

optimal inventory policy for a perishable item with demand function sensitive to price and time abstract we formulate a model for determining the optimal pricing order quantity and replenishment period for perishable items with price dependent and time dependent demand the items have a fixed shelf life and the demand rate decreases linearly in the selling price and polynomially over the time after replenishment until it vanishes either at the reservation price or at expiration time we prove that the three variable profit maximization problem can be reduced into a single variable problem in which the variable is the duration of the replenishment period we show that the profit function is strictly pseudo concave and provide means of obtaining the optimal policy three numerical examples are presented to demonstrate the model accompanied by a sensitivity analysis

s 1 s policies for perishable inventory we consider s 1 s policies for a single item whose lifetime is fixed and known with certainty demands are generated by a stationary poisson process and there is a positive leadtime for replenishment we believe this study gives the only analysis for perishables with a positive order leadtime the analysis involves the derivation of the stationary distribution of the s dimensional stochastic process corresponding to the time elapsed since the last s orders were placed this distribution is then used to obtain an expression for the expected cost rate of operating the system in steady state as a function of s a computer program has been developed to compute optimal s values and expected annual costs we report a computation for a variety of system parameters which show some of the unusual features of the problem finally we show how this model can be used in the context of a problem of optimizing availability of operating equipment subject to scheduled maintenance as well as random failure

on a finite horizon production lot size inventory model for deteriorating items an optimal solution abstract a generalized production lot size inventory model for deteriorating items over a finite planning horizon is considered the demand production and deteriorating rates are assumed to be known and continuous functions of time shortages are allowed and completely backlogged the conditions under which the system total cost attains its unique global minimum are derived an example which illustrate the applicability of theoretical results is also introduced

dynamic version of the economic lot size model this article originally appeared in management science october 1958 volume 5 number 1 pp 89 96 published by the institute of management sciences a forward algorithm for a solution to the following dynamic version of the economic lot size model is given allowing the possibility of demands for a single item inventory holding charges and setup costs to vary over n periods we desire a minimum total cost inventory management scheme which satisfies known demand in every period disjoint planning horizons are shown to be possible which eliminate the necessity of having data for the full n periods

bilateral trade with the sealed bid k double auction existence and efficiency for k in the unit interval the k double auction determines the terms of trade when a buyer and a seller negotiate transfer of an item the buyer submits a bid b and the seller submits an offer s trade occurs if b exceeds s at price kb 1 k s we model trade as a bayesian game in which each trader privately knows his reservation value but only has beliefs about the other trader s value existence of a multiplicity of equilibria is proven for a class of trader s beliefs for generic beliefs however these equilibria are shown to be ex ante inefficient

risk sharing from international factor income explaining cross country differences access to world capital markets and net investment income flows between countries help protect national income from country specific output shocks i empirically study what factors explain cross country differences in the extent of risk sharing from international factor income an index of investor protection is the leading causal variable for the estimated amount of risk sharing over the 1985 to 2004 period improving investor protection in russia to denmark s level implies five times larger risk sharing compared to the sample average these results indicate one possible way to reap large potential benefits from international risk sharing

risk sharing and industrial specialization regional and international evidence the authors provide empirical evidence that risk sharing enhances specialization in production to the best of their knowledge this well established and important theoretical proposition has not been tested before the empirical procedure is summarized as follows first the authors construct a measure of specialization in production and calculate an index of specialization for each of the european community ec and non ec oecd countries u s states canadian provinces japanese prefectures latin american countries and regions of italy spain and the united kingdom then they estimate the degree of capital market integration a measure of risk sharing within each of these groups of regions the ec countries the non ec oecd countries the united states canada japan italy spain and the united kingdom and rely on another author s estimate for latin america finally they perform a regression of the specialization index on the degree of risk sharing controlling for relevant economic variables they find a positive and significant relation between the degree of specialization of individual members of a group of countries provinces states or prefectures and the amount of risk that is shared within the group the authors perform regressions using variables such as shareholder rights and the size of the financial sector relative to gdp as instruments for the amount of inter regional risk sharing these regressions confirm that risk sharing facilitated by a favorable legal environment and a developed financial system is a direct causal determinant of industrial specialization this abstract was borrowed from another version of this item

robust control informational frictions and international consumption correlations abstract in this paper we examine the effects of model misspecification robustness or rb on international consumption correlations in an otherwise standard small open economy model with endogenous capital accumulation we show that in the presence of capital mobility in financial markets rb lowers the international consumption correlations by generating heterogeneous responses of consumption to productivity shocks across countries facing different macroeconomic uncertainty in addition we show that rb can also improve the model s predictions in three other moments of consumption dynamics the relative volatility of consumption to income the persistence of consumption and the correlation between consumption and output after calibrating the rb parameter using the detection error probabilities we show that the model can explain the observed international consumption correlations as well as the other consumption moments quantitatively finally we show that the main conclusions of our benchmark model do not change in an extension in which the agent cannot observe the state perfectly due to finite information processing capacity

inventory problems with perishable items fixed lifetimes and backlogging our model deals with a single product and a single stock location with poisson demand the replenishment leadtime from the external supplier is fixed the lifetime of the product is also fixed and aging is assumed to begin when the order is placed when the age of a unit has reached its lifetime the unit is useless and thus discarded from the system the replenishment policy is assumed to be an order up to s policy demand that cannot be met immediately is backordered we consider three different cases where the service requirements are represented by 1 backorder costs per unit 2 a service level constraint 3 backorder costs per unit and time unit cases 1 and 2 are solved exactly while an approximation is developed for case 3 we show how the results from an earlier paper assuming lost sales can be used to solve the considered problems our results are compared to the results in a related paper considering q r policies c 2009 elsevier b v all rights reserved less