to float or to fix evidence on the impact of exchange rate regimes on growth we study the relationship between exchange rate regimes and economic growth for a sample of 183 countries over the post bretton woods period using a new de facto classification of regimes based on the actual behavior of the relevant macroeconomic variables in contrast with previous studies we find that for developing countries less flexible exchange rate regimes are associated with slower growth as well as with greater output volatility for industrial countries regimes do not appear to have any significant impact on growth the results are robust to endogeneity corrections and a number of alternative specifications borrowed from the growth literature

joint pricing and ordering policy for two echelon imperfect production inventory model with two cycles abstract this study deals with an imperfect epq economic production quantity price dependent inventory model over two types of cycles in the first cycle the retailer sells only good product with actual price and in the second he sells the products with a discount price in the production run time the non conforming items are produced at a random rate and they are reworked after the regular production run time and the reworked items are almost perfect as good as original quality items the retailer starts the second cycle when a certain percent of good items are left to him after the completion of regular production the retailer continues simultaneously two cycles up to which both types of the products are available to him now our objective is to find out optimal ordering lot size and optimal price for which the profit of the integrated model is maximum also we check the best strategy of retailer for the time of starting second cycle a numerical example is provided to illustrate the behavior and application of the model

an economic order quantity model for an imperfect production process with entropy cost abstract among the assumptions of the classical economic order quantity eoq model is that all units that are purchased or produced are of perfect quality however this is frequently unrealistic since production processes deteriorate resulting in the production of defective products requiring rework some recent studies suggest that production systems performance might be improved by applying the first and second laws of thermodynamics to reduce system entropy or disorder this paper applies the concept of entropy cost to extend the classical eoq model under the assumptions of perfect and imperfect quality mathematical models are developed and numerical examples illustrating the solution procedure are provided accounting for entropy cost suggests that order quantities should be larger than the figures derived from the classical eoq model

optimal production lot with imperfect production process under permissible delay in payments and complete backlogging abstract the traditional economic production quantity epq model assumes that the production products are all perfect it is not always true in the real production system due to imperfect production process or other factors imperfect quality items may be produced furthermore it is well known that the total production inventory costs can be reduced by reworking the imperfect quality items produced with a relatively smaller additional reworking and holding costs in addition the permissible delay in payments offered by the supplier is widely adopted in the practical business market in this study we explore the effects of the reworking imperfect quality items and trade credit on the epq model with imperfect production processes and complete backlogging a mathematical model which includes the reworking and shortage costs interest earned and interest charged is presented besides an arithmetic geometric mean inequality approach is employed and an algorithm is developed to find the optimal production policy furthermore some numerical examples and sensitivity analysis are provided to demonstrate the proposed model

short comments on technical note the eoq and epq models with shortages derived without derivatives abstract we study the paper of ronald yang and chu that was recently published in the international journal of production economics to find the optimal solution for the eoq and epq models without derivatives we will offer a simple algebraic method to replace their sophisticated algebraic skill and then we point out a possible direction for further research

model and heuristic algorithm of the joint replenishment problem with complete backordering and correlated demand abstract in practice demands for items are often correlated with each other because of cross selling effects traditional inventory models hold the assumption that demands are independent which may lead to the risk of misestimating the inventory cost of associated items this paper addresses a multi item inventory system where demands for some minor items are correlated with that for a major item because of the cross selling demand for minor items may either be raised by the sales of the major item or be pulled down by the unsatisfied demands for the major item thus a joint inventory policy considering correlations across items should be pursued considering general integer policy we propose a joint replenishment problem jrp model with complete backordering and correlated demand through the use of derivatives the model is transformed to minimize a cost function with respect to multiples of the major item s order cycle given that the optimal solution should offer a trade off between the ordering cost and the inventory holding cost of each item we develop a heuristic algorithm by adjusting the replenishment frequencies of minor items to solve the model the heuristic is tested by simulated numerical examples and shows satisfactory results

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

note on economic production quantity model for items with imperfect quality a practical approach abstract in this note we present a simple approach for determining the economic production quantity for an item with imperfect quality we compare the results based on the simple approach with the optimal method for determining the lot size and show that almost optimal results are obtained using the simple approach

economic order quantity models for imperfect items with buy and repair options abstract one of the celebrated extensions of the economic order production quantity eoq epq model is one that assumes a received shipment contains a fraction of imperfect non conforming quality items where these items detected by 100 screening are sold as a single batch at a discounted price this paper revisits this model salameh and jaber 2000 int j prod econ 64 1 59 64 and extends it by assuming that a shipment is coming from a distant supplier and therefore it is not feasible to replace the imperfect items with an additional order to the same supplier to address this restriction two models are presented the first assumes that imperfect items are sent to a repair shop who charges a cost plus a markup margin while the second model assumes that imperfect items are replaced by good ones from a local supplier at a higher cost the inventory environment assumed in this paper is relevant in todays globalised supply chains thus practical implications of the problem faced are discussed numerical results are also presented and discussed the results show that there exists a threshold value of the unit purchase cost of an emergency ordered item and a fraction of defectives to which it is decided to either buy or repair

a multi item fuzzy economic production quantity problem with a finite production rate abstract inventory management and production planning are essential tasks for every company in the industry therefore the development of a large set of economic order quantity eoq models is needed in this paper a fuzzy multi item economic production quantity epq model is developed this paper contributes to the state of the art with a theoretical study of a problem where a company has to decide the size of some production batches under uncertain cycle times the uncertainty will be handled with triangular fuzzy numbers and an analytical solution will be found to the optimization problem

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

eoq models for a coordinated two level international supply chain considering imperfect items and environmental impact abstract for a two level supply chain models are presented to determine the optimal production shipment policy for items with imperfect quality in three different scenarios a both the vendor and the buyer are in the same country b the vendor and the buyer are in different countries where the stochastic behavior of the exchange rate between the two countries is modeled using a mean reverting process and c environmental impact is incorporated in determining the optimal production shipment policy by taking into account the fixed and variable carbon emission costs the objective is to minimize the total expected cost per unit time for each scenario considering equal shipment size the total expected cost per unit time is derived and the solution procedure is proposed numerical examples are presented and the results are discussed

managing real time demand fluctuation under a supplier retailer coordinated system abstract we have considered a supplier retailer system that operates under an agreed coordinated policy with an imperfect production process and a possibility of having demand fluctuation in this paper a dynamic planning process is proposed to deal with short term demand fluctuations to do this a mathematical model was first developed for a single fluctuation either for increasing or decreasing demand rate the model generates a revised plan after the occurrence of the fluctuation event we also propose a new and efficient heuristic to solve the developed model secondly multiple fluctuations have been considered for which a new occurrence may or may not affect the revised plan of earlier occurrences and we extend the heuristic so that is capable of dealing with multiple demand fluctuations on a real time basis we have generated a good number of random test problems and also solved the model using a genetic algorithm in order to compare the solutions with our heuristic the comparison confirmed the consistent performance of our developed heuristic and also its lower computational time numerical examples and sensitivity analysis have been presented to explain the usefulness of the developed model

the eoq with backlogging derived without derivatives abstract in previous work the eoq formula without consideration to backlogging has been given a derivation without reference to the use of derivatives neither for necessary conditions nor for second order sufficient conditions furthermore this algebraic derivation immediately provided the value of the average cost function in optimum this paper extends the previous result to the eoq formula taking the backlogging case into consideration it is shown that a similar derivation immediately provides the corresponding results for this case

hiv status and labor market participation in south africa abstract we use econometric methods based on the propensity score to estimate the causal effect of hiv status on employment outcomes in south africa relying on rich data from a national survey which included hiv testing we control for systematic differences between hiv positive and hiv negative individuals we provide the first nationally representative estimates of the impact of hiv status on employment outcomes for southern africa being hiv positive is associated with an increase of 6 to 7 percentage points in the likelihood of unemployment overall and 10 to 11 percentage points for those who are less educated this disadvantage reinforces existing inequalities in south africa

an eoq model with random variations in demand this paper presents a model that incorporates variations in the demand rate at random time points into the inventory planning decision these changes in demand may occur due to economic recessions labor strife starting or ending or other events that result in a period of time during which the rate of demand is shifted up or down from its current level the paper uses system point level crossing theory to derive expressions for the distribution and expected value of on hand inventory ordering rate and the expected total cost rate for a given ordering policy a sensitivity analysis is conducted and a number of qualitative properties are provided to illustrate the use of the results to obtain optimal order quantities

an economic order quantity model with defective items and shortages abstract the fundamental assumption of an economic order quantity eoq model is that 100 of items in an ordered lot are perfect this assumption is not always pertinent for production processes because of process deterioration or other factors this paper develops an eoq model for that each ordered lot contains some defective items and shortages backordered it is assumed that 100 of each lot are screened to separate good and defective items which are collection of imperfect quality and scrap items the effect of percentage defective on optimal solution is studied while numerical examples are provided for the developed model

the contribution of female health to economic development we analyze the economic consequences for less developed countries of investing in female health we do this through developing and calibrating a novel micro founded dynamic general equilibrium model in which parents trade off the number of children against investments in their education and in which we allow for health related gender differences in productivity we show that better female health speeds up the demographic transition and thereby the take off toward sustained economic growth by contrast male health improvements delay the transition and take off because ceteris paribus they raise fertility investing in female health is therefore a potent lever for promoting development

the long run economic costs of aids a model with an application to south africa primarily a disease of young adults acquired immuno deficiency syndrome aids imposes economic costs that could be devastatingly high in the long run by undermining the transmission of human capital the main driver of long run economic growth across generations aids makes it harder for victims children to obtain an education and deprives them of the love nurturing and life skills that parents provide these children will in turn find it difficult to educate their children and so on an overlapping generations model is used to show that an otherwise growing economy could decline to a low level subsistence equilibrium if hit with an aids type increase in premature adult mortality calibrating the model for south africa where the hiv prevalence rate is over 20 percent simulations reveal that the economy could shrink to half its current size in about four generations in the absence of intervention programs to combat the disease and to support needy families could avert such a collapse but they imply a fiscal burden of about 4 percent of gross domestic product gdp

generalized eoq formula using a new parameter coefficient of backorder attractiveness abstract this paper introduces and examines a generalized eoq formula based on the model with linear and fixed backordering costs the new square root formula is a combination of two well known classical models the basic eoq model without stockouts and the eoq model with backorders and linear backordering costs helping to combine the two is a new parameter a fractional coefficient capturing the attractiveness of backorders the coefficient is explained and discussed the paper concludes with a brief discussion of generalizations in eoq models including epq

an eoq model with imperfect quality items inspection errors shortage backordering and sales returns abstract in practice the items received in a lot may contain defective items and the screening process to eliminate the defective items may involve both a type i and a type ii error due to the defective items and the inspection errors shortages may sometimes occur in this paper we develop an economic order quantity model with imperfect quality items inspection errors shortage backordering and sales returns a closed form solution is obtained for the optimal order size the maximum shortage level and the optimal order reorder point if shortages are not allowed we adopt the order overlapping scheme proposed by maddah et al 2010 computers and industrial engineering 58 4 691 695 to develop an eoq model to prevent shortages during the screening process numerical examples show the impacts of the defective probability the inspection errors and the holding and backordering costs on the optimal solution

strict dollarization and economic performance an empirical investigation in this paper we analyze the macroeconomic record of strictly dollarized economies in particular we investigate whether dollarized countries have historically exhibited faster growth and lower volatility than countries with a domestic currency we analyze this issue by using a treatment regression analysis that estimates jointly the probability of being a dollarized country and outcome equations our analysis indicates that the probability of being a dollarized country depends on regional geographical political and structural variables our results also suggest that gdp per capita growth has not been statistically different in dollarized and in non dollarized countries we also find that volatility has been significantly higher in dollarized than in non dollarized economies these results are robust to the estimation technique and to the sample used

eoq with a correlated binomial supply abstract this paper considers a variant of the economic order quantity eoq model under random supply a binomial supply model is adopted where every item received is of imperfect quality with the same probability we study the realistic case where the qualities of items in an order are correlated and draw useful insights the most interesting of which is that correlation decreases the order size several practical correlation patterns are investigated and discussed we also show that several commonly used models in the literature can be represented by an equivalent correlated binomial supply model

exchange rate regime durability and performance in developing versus advanced economies abstract drawing on new data and advances in exchange rate regimes classification we find that countries appear to benefit by having increasingly flexible exchange rate systems as they become richer and more financially developed for developing countries with little exposure to international capital markets pegs are notable for their durability and relatively low inflation in contrast for advanced economies floats are distinctly more durable and also appear to be associated with higher growth for emerging markets our results parallel the baxter and stockman classic exchange regime neutrality result though pegs are the least durable and expose countries to higher risk of crisis

disaggregation and consolidation of imperfect quality shipments in an extended epq model abstract we consider a standard economic production quantity epq model due to manufacturing variability a fraction p of the produced inventory will have imperfect quality where p is a random variable with a known distribution we consider a 100 inspection policy and further assume that the inspection rate is larger than that of production thus all imperfect quality items will be detected by the end of the production cycle for such an augmented epq model we first derive the new optimal production quantity assuming that the imperfect quality items are salvaged once at the end of every production cycle then we extend this base model to allow for disaggregating the shipments of imperfect quality items during a single production run finally we consider aggregating or consolidating the shipments of imperfect items over multiple production runs under both scenarios we derive closed form expressions for both the economic production quantity and the batching policy and show that our desegregation consolidation schemes can lead to significant cost savings over the base model

optimal lot sizing integration policy under learning and rework effects in a manufacturer retailer chain abstract most research in economic manufacturing order quantity management assumes that all products are of perfect quality and are produced at a constant production rate one result of this assumption is that the number of units produced in a given period is constant which is not the case in real life most production systems produce items which are of perfect quality along with some that are of imperfect quality defective items as well as the learning effect affect production and inventory costs thereby shaping the performance of the manufacturer retailer chain the present study uses the nash stackelberg and cooperation games to model an imperfect production system to investigate the combined effects of lot sizing size integration the learning effect imperfect production and the rework process on a manufacturer retailer channel this study also demonstrates the optimal properties of the proposed models develops a search algorithm for obtaining optimal solutions and conducts a numerical study to seek structural and quantitative insights into the structure of the proposed models in addition it analyzes the sensitivity of the solutions in relation to the major parameters

epq models with varying setup cost abstract in this paper the classical economic production quantity epq model is generalized by considering a relationship between the setup cost and the production run length the dependency between the setup cost and run length can be related to process deterioration and learning and forgetting effects two models are developed the first of which is for the case when shortages are not allowed and the other one permits shortages the cost functions associated with these models are proved to be convex and optimal solutions are determined results show that the relationship between setup cost and production run length has a significant impact on the optimal lot size and average total cost in the epq model numerical examples are presented to demonstrate the utility of the models

the gift of the dying the tragedy of aids and the welfare of future african generations this paper simulates the impact of the aids epidemic on future living standards in south africa i emphasize two competing effects on the one hand the epidemic is likely to have a detrimental impact on the human capital accumulation of orphaned children on the other hand widespread community infection lowers fertility both directly through a reduction in the willingness to engage in unprotected sexual activity and indirectly by increasing the scarcity of labor and the value of a woman s time i find that even with the most pessimistic assumptions concerning reductions in educational attainment the fertility effect dominates the aids epidemic on net enhances the future per capita consumption possibilities of the south african economy

the deterministic eoq with partial backordering a new approach previous authors have shown that if demand that cannot be filled from stock is partially backordered then using the full backordering model or assuming that all stockouts will result in lost sales can lead to substantial increases in cost relative to using a model that specifically recognizes the percentage of the stockouts that will be backordered the models that these authors developed resulted in procedures or equations that are relatively difficult to use in this paper we take a different approach to modeling the deterministic eoq with partial backordering that results in equations that are more like the comparable equations for the basic eoq and its full backordering extension

inflation targeting in latin america toward a monetary union this paper examines how monetary policy decisions in brazil regarding short term interest rates have affected the term structure of interest rates we apply an event study methodology in two distinct periods between january 2000 and august 2003 right after the implementation of the inflation targeting in brazil and between september 2003 and july 2008 the main results are 1 the surprise effects have decreased 2 the explanation power has increased in the second period indicating enhancement of monetary policy 3 market participants adjust their expectations with greater advance 4 the surprise effects of decisions on short term rates on the term structure of interest rates are now close to those found in the usa and germany but higher to those found in the uk and italy therefore the results indicate that fixed income market expectations are better adjusted to the central bank anti inflationary policy

adapting the newsvendor model for infinite horizon inventory systems abstract we address inventory decisions in the context of the reorder point order quantity policy in infinite horizon stochastic lead time demand inventory systems in which the parameters may be non stationary we develop a heuristic policy based on the simple economic order quantity eoq model and the one period newsvendor model using illustrative numerical examples we demonstrate that our simple and easy to understand heuristic policy performs nearly as well as the optimal policy derived from complicated mathematical procedures our heuristic policy is simple easy to implement and flexible in that it can be easily adapted to situations when the parameters of the inventory system may change analytical modeling under non stationary parameters would be extremely complex and the derivation of closed form optimal policies is mathematically intractable in most cases in such cases practitioners will find our heuristic policy an attractive option

does the exchange rate regime matter for real shocks evidence from windstorms and earthquakes abstract does the choice of exchange rate regime affect an economy s adjustment to real shocks exploiting the unpredictability and economic exogeniety of windstorms hurricanes and typhoons and earthquakes this paper assesses the often contrasting answers found in the theoretical literature there is robust evidence that exchange rate flexibility helps an economy better adjust to real shocks and consistent with the channels emphasized in the classic literature on exchange rates and shocks differences in the behavior of the export sector help explain the different reactions between the two regimes

an operational policy for a three stage distributive supply chain system with retailers backorders abstract this research deals with a production inventory problem consisting of three stage tree type single producer multi distributor and multi retailer supply chain network where a model has been developed for achieving the lowest total cost for operating a supply chain system with allowable shortage in this research the shortage is assumed to occur in a form of backorder the refrigerator manufacturing can suitably be used to illustrate the scenario which makes the situation more rational and realistic by assumptions the customers will not go somewhere else the cost of lost sale is not included in this case the total cost of this tree type distributive supply chain system is comprised of setup costs and holding costs at all echelons and the backorder cost at retailer level only a replenishment policy is sought to operate the system at a minimum cost the problem is formulated as an unconstrained mixed integer programming problem and a newly developed doubly hybrid meta heuristic algorithm is adopted as the solution procedure the solutions which determine the desired replenishment policy for the producer distributors and retailers are obtained to minimize the total system cost a sensitivity analysis is performed to evaluate the outcome of the proposed solution procedure presented in this research numerical results are generated to demonstrate the solution procedure and future research is indicated for further study

stuck on gold real exchange rate volatility and the rise and fall of the gold standard 1875 1939 abstract did the gold standard diminish macroeconomic volatility supporters thought so critics thought not and theory offers ambiguous messages hard regimes like the gold standard limit monetary shocks by tying policymakers hands but exchange rate inflexibility compromises shock absorption in a world of real disturbances and nominal stickiness a model shows how lack of flexibility affects the transmission of terms of trade shocks evidence from the late nineteenth and early twentieth century exposes a dramatic change the classical gold standard did absorb shocks but the interwar gold standard did not supporting the view that the interwar gold standard was a poor regime choice

an economic production quantity model for deteriorating items with multiple production setups and rework abstract rework is one of the main issues in reverse logistic and green supply chain since it can reduce production cost and environmental problem many researchers focus on developing rework model but few of them developed model for deteriorating items in this paper we develop an economic production quantity epq model for deteriorating items with rework in one cycle production facility can produce items in m production setups and one rework setup m 1 policy an example and sensitivity analysis is shown to illustrate the model the results show that the deteriorating rate affects the optimal cost per unit time but the effect is not significant the parameters that significantly affect the optimal total cost per unit time are the serviceable holding cost the production setup cost and the demand rate

how many parts to make at once reprinted from factory the magazine of management volume 10 number 2 february 1913 pp 135 136 152 interest on capital tied up in wages material and overhead sets a maximum limit to the quantity of parts which can be profitably manufactured at one time set up costs on the job fix the minimum experience has shown one manager a way to determine the economical size of lots

an easy derivation of the order level optimality condition for inventory systems with backordering we analyze the classical inventory model with backordering where the inventory position is controlled by an order level order quantity policy the cost for a backorder contains a fixed and a time proportional component demand can be driven by any discrete process order lead times may be stochastic and orders are allowed to cross the optimality condition for the order level given some predetermined order quantity is derived using an easy and insightful marginal cost analysis it is further shown how this condition can easily be approximately rewritten in well known forms for special cases

a note on how to compute economic order quantities without derivatives by cost comparisons abstract a different approach to obtain the economic order quantity and several extensions without taking derivatives is presented in contrast to previous contributions to this discussion cost comparisons in a finite horizon and analyzing the limiting behavior are used rather than algebraic manipulations of the average cost function and comparison of coefficients

an optimal policy for a single vendor single buyer integrated production inventory problem with process unreliability consideration abstract this article develops a model to determine an optimal integrated vendor buyer inventory policy for flawed items in a just in time manufacturing environment the objective is to minimize the total joint annual costs incurred by the vendor and the buyer the production process is assumed to deteriorate during processing and produces a certain number of defective items for practical purpose the article is concerned with the policy in which the delivery quantity to the buyer is identical at each replenishment the expected annual integrated total cost function is derived and a solution procedure is established to find out the optimal solution finally the solution technique is illustrated with a numerical example available in the literature

a century of evolution from harris s basic lot size model survey and research agenda abstract determining the economic lot size has always represented one of the most important issues in production planning this problem has long attracted the attention of researchers and several models have been developed to meet requirements at minimum cost in this paper we explore and discuss the evolution of these models during one hundred years of history starting from the basic model developed by harris in 1913 up to today following harris s work a number of researchers have devised extensions that incorporate additional considerations the evolution of eoq theory strongly reflects the development of industrial systems over the past century here we outline all the research areas faced in the past by conducting a holistic analysis of 219 selected journal papers and trying to give a comprehensive view of past work on the eoq problem finally a new research agenda is proposed and discussed

lot sizing with a markov production process and imperfect items scrapped abstract this paper considers an inventory system within the economic order quantity eoq model framework under random supply the production process can go out of control with a constant probability and start producing imperfect quality items such a system has been studied in the literature under the assumption that defective items are reworked instantaneously and returned to inventory in some situations imperfect quality items are not necessarily defective and are removed from the inventory to be used elsewhere this paper develops two models where imperfect items are removed from inventory the first model finds the expected cost and optimal lot size assuming that imperfect quality items are removed from inventory at no cost the second model assumes that batches of imperfect quality are consolidated and shipped together due to economies of scale in shipping analytical and numerical results are developed for both models revealing several managerial insights

economic production quantity for fuzzy demand quantity and fuzzy production quantity abstract in the fundamental production inventory model in order to solve the economic production quantity epq per cycle we always fix both the demand quantity and the production quantity per day but in the real situation both of them probably will have little disturbances every day therefore we should fuzzify both of them to solve the ecoomic production quantity q per cycle the purpose of this paper is to investigate a computing schema for the epq in the fuzzy sense we find that after defuzzification the total cost is although slightly higher than in the crisp model however it permits better use of the epq in the crisp arising with little disturbances in the production and demand

the advantage of tying one s hands ems discipline and central bank credibility abstract it is often argued that the ems is an effective disciplinary device for inflation prone countries in europe since it forces the respective policy makers to pursue more restrictive monetary policies than they would otherwise it is not clear however why these countries should submit themselves to such discipline this paper argues that to answer this question appropriately one must consider that ems membership brings potentially large credibility gains policy makers in inflation prone countries the reason is that not only it attaches an extra penalty to inflation in terms of real appreciation but makes the public aware that the policy maker is faced with such penalty and thus helps to overcome the inefficiency stemming from the public s mistrust of the authorities

assessing the impact of aids on the growth path of the malawian economy abstract a modified solow growth model is used to simulate the impact of the aids epidemic on output capacity and other key macroeconomic aggregates in malawi comparing a counterfactual no aids scenario to medium and extreme aids projections suggests that average real gdp growth over the 1985 2010 period will be 0 2 0 3 1 2 1 5 percentage points lower in the medium extreme case relative to the no aids case as a result the size of the economy by the year 2010 will be reduced from a real gdp of 5 03 billion constant 1985 kwacha without aids to 4 81 4 77 3 80 3 46 billion kwacha in the medium extreme scenario

the benefits and costs of monetary union in southern africa a critical survey of the literature with the 14 members of the southern african development community sadc having set the objective of adopting a common currency for the year 2018 an expanding empirical literature has emerged evaluating the benefits and costs of a common currency area in southern africa this paper reviews that literature focusing on two categories of studies 1 those that assume that a country s characteristics are invariant to the adoption of a common currency and 2 those that assume that a monetary union alters an economy s structure resulting in trade creation and credibility gains the literature reviewed suggests that a relatively small group of countries typically including south africa satisfies the criteria necessary for monetary unification the literature also suggests that in a monetary union comprising all sadc countries and a regional central bank that sets monetary policy to reflect the average economic conditions e g fiscal balances in the region the potential losses i e higher inflation from giving up an existing credible national central bank a relevant consideration for south africa could outweigh any potential benefits of trade creation resulting from a common currency

dollarization does promote trade abstract this study re evaluates the treatment effect of dollarization on trade while explicitly controlling for self selection of policy adoption employing a variety of propensity score matching methods we show that dollarization not only increases bilateral us trade with dollarized countries but promotes a dollarizer s bilateral trade with other dollar zone countries as well

an imperfect production process in a volume flexible inventory model abstract this paper hypothesizes an imperfect production inventory system where the items produced are a mixture of perfect and imperfect quality some of the imperfect quality items can be sold at a reduced selling price the unit production cost is taken to be a function of the finite production rate which is treated as a decision variable the mathematical expression for the expected profit function is derived and it is maximized subject to different constraints of the system using interior penalty function method for constrained optimization the algorithm of which is given the solution procedure is illustrated with the help of numerical examples the sensitivity of each variable to changes in the values of the parameters of the system is examined lastly various issues conforming the system are discussed

health nutrition and economic development the relationship between health and economic development is explored focusing on nutrition based health indicators the spotlight is placed on the inter related feedbacks between the influence of health on productivity on one hand and the influence of income on health status on the other disentangling causality in these relationships has preoccupied much of the literature we evaluate different empirical strategies that have been adopted and assess the results there is now a body of evidence based on careful empirical studies that demonstrates a causal relationship between health and labor productivity there is also evidence that at least among the very poor additional income is spent on improved nutrition there are two issues that have received little attention although we argue they are likely to be very important first measurement of health is discussed in detail evidence is presented on how taking into account differences in the extent of measurement error is critical for interpreting the impact of health on wages the same theme emerges in studies of the effect of income on health specifically calorie intake the key role of non linearities in these relationships is highlighted and we demonstrate that a good deal of the variation in estimates of income elasticities of demand for calories can be ascribed to the role of measurement and functional form authors

an integrated production inventory model with imperfect production processes and weibull distribution deterioration under inflation abstract this study develops an integrated production and inventory model from the perspectives of both the manufacturer and the retailer the model assumes a varying rate of deterioration partial backordering inflation imperfect production processes and multiple deliveries the elapsed time until the production process shift is assumed to be arbitrarily distributed the discounted cash flow and classical optimization technique are used to derive the optimal solution a numerical example including the sensitivity analysis is given to validate the results of the production inventory model the integrated decision results in lower optimal joint cost compared with an independent decision by the manufacturer and the retailer

the economic order quantity model revisited an extended exergy accounting approach abstract the economic order quantity eoq model has been popular among academicians and practitioners for decades despite the many variants of the eoq that have appeared in the literature to fine tune it to reality it still has limitations a major one is that it does not take into account the hidden costs inherent in inventory systems some of these costs relate to sustainability issues including environmental social labor and economic effects this paper considers some of these costs referred to as the exergetic costs and estimates them using the extended exergy accounting eea approach extended exergy accounting assigns equivalent exergetic values to capital labor and environmental remediation costs of a system the analysis combines the classical exergy analysis with the sustainability factors which are the labor capital and environment the paper uses an exergetic model to determine the eoq inventory policies for three firms operating in the usa germany and china the results show that the eoq is different for the three firms because the equivalent exergy of capital labor and environment remediation costs is different in each country

fewer monies better monies in the aftermath of emerging market crises from russia to asia and latin america there is a quest for better monetary arrangements that are more crisis proof fixed rates are out flexible rates are in with a policy focus on inflation targeting but there is of course the alternative of abolishing exchange rates all together this paper revisits the issue of dollarization or currency boards to review what arguments in the debate stand up the case for flexible exchange rates emphasizes the need for a tool to accomplish relative price adjustment this paper argues that in an intertemporal perspective most shocks require financing in the capital market rather than adjustment moreover countries frequently do not use their flexible rate to play a cyclical role and as a result only a pay a premium for the option to depreciate but do not take advantage of the flexibility on the contrary they engineer systematic overvaluation in the context of inflation targeting

an eoq model with backorders and rejection of defective supply batches abstract we consider a single echelon inventory installation under the classical eoq with backorders paradigm to study the effects of supply quality on cost performance previous research on imperfect supply quality has focused on variants of the proportional deterministic or random yield problem where supply batches are all accepted and then used after screening any defects in this paper we study an alternative setting where entire supply batches may be defective below quality standards and therefore rejected on arrival note that such supply flow disruptions are analogous to those considered within the economic order quantity with disruptions eoqd area of research we first present an exact model for the system expected cost and show its convexity optimal cost and respective values of the decision variables i e planned order quantity and backorders are then obtained in a closed form interestingly under perfect supply quality all expressions reduce to those of classical eoq analytical and computational results reveal the serious impact of inferior supply quality on system cost as well as the sensitivity of the system parameters

optimal vendor investment for reducing defect rate in a vendor buyer integrated system with imperfect production process this paper investigates a single vendor single buyer integrated production inventory model with stochastic demand and imperfect production process it is assumed that there is an inspection activity on the part of the buyer with a fixed screening rate greater than the demand rate the vendor invests money in order to improve the production process quality and reduce the number of defectives the expected annual integrated total cost is derived under the n shipment policy and an iterative procedure is suggested to determine the optimal decisions the benefit of investment in reducing the defect rate is illustrated by way of numerical examples it is observed that the higher the defect rate the more beneficial the investment numerical studies further explore that an increased demand requires an increased investment to optimize the total cost

economic production quantity model for items with imperfect quality abstract the assumptions necessary to justify the use of economic production quantity epq eoq models are rarely met to provide mathematical models that more closely conform to actual inventories and respond to the factors that contribute to inventory costs the models must be extended or altered this paper hypothesizes a production inventory situation where items received or produced are not of perfect quality items of imperfect quality not necessarily defective could be used in another production inventory situation that is less restrictive process and acceptance control the electronics industry gives good examples of such situations this paper extends the traditional epq eoq model by accounting for imperfect quality items when using the epq eoq formulae this paper also considers the issue that poor quality items are sold as a single batch by the end of the 100 screening process a mathematical model is developed and numerical examples are provided to illustrate the solution procedure

economic order quantity for items with imperfect quality revisited abstract we rectify a flaw in an economic order quantity eoq model with unreliable supply characterized by a random fraction of imperfect quality items and a screening process developed by salameh and jaber 2000 economic production quantity model for items with imperfect quality international journal of production economics 64 1 3 59 64 this leads to simple expressions of the optimal order quantity and expected profit per unit time we then analyze the effect of screening speed and variability of the supply process on the order quantity and show that the order quantity in our model is larger than that of the classical eoq model when the variability of the yield rate is reasonably low in addition we extend the model by allowing for several batches of imperfect quality items to be consolidated and shipped in one lot this is likely to be useful when there are economies of scale in shipping of imperfect quality items finally we present numerical results to illustrate the application of the model and draw insights

optimal ordering policies in response to a discount offer corrections abstract recently sarker and kindi 2006a optimal ordering policies in response to a discount offer international journal of production economics 100 2 195 211 presented an inventory model from the purchaser s perspective to determine the optimal ordering policies in response to a discount offer established by the supplier for five possible cases this study presents some practical extensions to the optimal ordering policies developed by sarker and kindi 2006a optimal ordering policies in response to a discount offer international journal of production economics 100 2 195 211

economic production quantity model for items with imperfect quality subject to learning effects abstract salameh and jaber 2000 international journal of production economics 64 59 64 developed an inventory situation where items received are not of perfect quality defective and after 100 screening imperfect quality items are withdrawn from inventory and sold at a discounted price this paper extends the work of salameh and jaber by assuming the percentage defective per lot reduces according to a learning curve which was empirically validated by data from the automotive industry mathematical models are developed with numerical examples provided and discussed the developed model was compared with the model of salameh and jaber to emphasize the importance of learning

optimizing the economic lot size of a three stage supply chain with backordering derived without derivatives abstract multi stage supply chain management integration provides a key to successful international business operations this is because the integrated approach improves the global system performance and cost efficiency the integrated production inventory models using differential calculus to solve the multi variable problems are prevalent in operational research this paper extends the integrated vendor buyer inventory problem by yang and wee yang p c wee h m 2002 the economic lot size of the integrated vendor buyer system derived without derivatives optimal control applications and methods 23 163 169 to solve the multi variable problems in the supply chain and simplifies the solution procedure using a simple algebraic method as a result the solution procedure may be easily understood and applied so as to derive the optimal solution

persistent norms and tipping points the case of female genital cutting abstract more than 200 million women alive today have undergone female genital cutting fgc despite the associated negative health outcomes the practice has persisted for generations the prevailing theory of fgc persistence is that fgc is a social coordination norm which implies that if a sufficient number of community members agree to abandon fgc a tipping point is reached and the rate of fgc will fall to zero recent empirical evidence is inconsistent with this theory this paper formalizes an alternative theoretical explanation in which households have heterogeneous thresholds i e the rate of fgc in their community at which the household switches from practicing to not practicing fgc this threshold heterogeneity removes the certainty that a tipping point exists and introduces the possibility of a stable internal equilibrium in the rate of fgc in a community using a dataset of more than 27 000 women born across 4 5 decades in burkina faso i use a novel technique to construct community level distributions of household thresholds these distributions show that some communities in burkina faso have tipping points while some have a stable internal equilibrium i find suggestive but statistically insignificant evidence that communities with a larger share of educated women higher poverty rates and lower population density are more likely to have a tipping point additionally the empirical method developed in this paper has applications to the evolution of other social phenomena such as technology adoption voting behavior and racial segregation

the economic production quantity epq with shortage derived algebraically abstract previously in several papers and textbooks the classical economic order quantity eoq and the economic production quantity epq formulas for the shortage case have been derived using differential calculus and solving two simultaneous equations derived from setting the two first partial derivatives to zero with the need to prove optimality conditions with second order derivatives in a previous original piece of work a new approach to find the eoq with backlogging using some slight algebraic developments appeared this paper extends the mentioned algebraic approach to the epq formula taking shortages into consideration within the case of only one backlog cost per unit and time unit the final expressions provide the same formulas that are available in the classic textbooks on inventory theory

three echelon supply chain coordination considering duopolistic retailers with perfect quality products abstract this paper explores channel coordination and profit division issues of a manufacturer distributer duopolistic retailers supply chain for a product where the manufacturer supplies lotsize of the product that contains a random portion of imperfect quality item in manufacturer stackelberg vertical game setting the duopolistic retailers three behaviours cournot collusion and stackelberg are discussed besides analyzing the effect of imperfect quality product on optimal decisions the paper depicts the hybrid contract mechanism so that all units quantity discount with franchise fee resolves channel conflict though unable to provide win win outcome for surplus profit division the paper proposes two sequential bargaining processes backward and forward where outcome of a nash bargaining is dependent on the previous it is found that for channel coordinated win win profit the manufacturer prefers collusion stackelberg and cournot while the retailer prefers the reverse and both prefer backward sequential bargaining but the distributers preference depends on the target profit that it sets during the bargaining process the proposed mechanisms are illustrated by a numerical example

economic ordering quantity models for items with imperfect quality abstract in this paper we first look at the issue of non shortages in models with proportional imperfect quality when the proportion of the imperfects is a random variable more specifically we revisit the papers of salameh and jaber int j prod econom 64 2000 59 and chan et al prod plann control 14 2003 588 and we point out that the sufficient conditions given in these papers to ensure that shortages will not occur may not really prevent their occurrence next considering the timing of withdrawing the imperfect quality items from stock we clarify a point not clearly stated in salameh and jaber int j prod econom 64 2000 59 and we extented this model to the case in which withdrawing takes place at the end of the planning horizon finally we establish that the objective of maximizing the mean average profit which was set in salameh and jaber int j prod econom 64 2000 59 is superfluous and the results given there can be obtained by ignoring the revenue issues assumed in the model and minimizing directly the mean average cost

economic order quantity for growing items abstract economic order production quantity eoq epq models have generally been presented for manufacturing products incorporating some important features of a specific category of products different eoq epq models have been proposed in literature this study proposes a new class of inventory models i e a model for a specific type of inventory items growing items poultry and livestock are good examples of growing inventory items we begin by proposing a general mathematical model which can be used for different types of growing items followed by a particular mathematical model for a specific type of poultry we calculate the optimal order quantity of the growing items at the start of a growing cycle the optimal length of the growing cycle and the optimal total profit numerical examples are provided for a type of poultry to illustrate the model a sensitivity analysis is presented to study the effect of the main parameters of the model in terms of its decision variables and objective function the results of the sensitivity analysis suggest that production costs are the most crucial parameter

the effects of learning and forgetting on the optimal production lot size for deteriorating items with time varying demand and deterioration rates abstract in this paper we shall study the effects of learning and forgetting on the production lot size problems for an infinite planning horizon items deteriorate while they are in storage and both demand and deterioration rates are arbitrary functions of time the instantaneous production rate presented herein is dependent on the time required to produce the first unit at the beginning of production process the number of units remembered and the fixed learning slope component the forgetting slope is represented by an approximation of the minimum break to which the manufacturer assumes total forgetting so that it allows variable total forgetting breaks the system is subject to learning in the production stage and to forgetting while production ceased so that the optimal manufactured quantity for any given cycle is dependent on the instantaneous production rate a closed form for the total relevant costs is derived and rigorous mathematical methods that guide to a minimum total cost of the underlying inventory system are introduced illustrative examples which explain the applications of the theoretical results as well as their numerical verifications are also given

economic order quantity model for items with imperfect quality with learning in inspection abstract the economic order quantity eoq model is the simplest and earliest inventory model in the literature its simple mathematics is attributed to its assumptions which are rarely met salameh and jaber 2000 economic production quantity model for items with imperfect quality int j prod econ 64 59 64 addressed one of these assumptions that items received or produced are not of perfect quality this paper extends salameh and jaber s work for the case where there is learning in inspection the model is realistic in that it considers situations of lost sales and backorders mathematical models are developed with numerical examples provided and results discussed for the cases of i partial transfer of learning ii total transfer of learning and iii no transfer of learning