optimal pricing and lot sizing under conditions of perishability finite production and partial backordering and lost sale abstract perishable products constitute a sizable component of inventories common questions in a production and selling situation involving a perishable or a non perishable product are what should be the price and what should be the size of the replenishment when demand for the product is price sensitive pricing and lot sizing decisions are interdependent similarly when a product is highly perishable the demand may need to be backlogged to avoid costs due to deterioration i e perishability and backlogging are complementary conditions in this paper we consider the pricing and lot sizing problem for a perishable good under finite production exponential decay and partial backordering and lost sale the backlogging phenomenon in the literature is often modeled using backordering and lost sale costs these cost parameters however are not easy to estimate in practice in this paper we use a new approach to model backlogging of demand in this approach customers are viewed to be impatient the backlogging option gets used only when it is economic to do so we extend the analysis presented for a perishable product to the case in which the product is non perishable

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

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

the effects of inflation and time value of money on an economic order quantity model with a random product life cycle abstract for several decades the economic order quantity eoq model and its variations have received much attention from researchers recently there has been an investigation into an eoq model incorporating a random product life cycle and the concept of time value of money this paper extends the previous research in several areas first we investigate the impact of inflation on the choice of replenishment quantities second the unit cost which has been inadvertently omitted in the previous research is included in the objective function to properly model the problem third we consider the normal distribution as a product life cycle in addition to the exponential distribution fourth we develop a simulation model which can be used for any probability distribution

replenishment and pricing policy for deteriorating items taking into account the time value of money abstract a deteriorating inventory model taking into account the time value of money is developed for a deterministic inventory system with price dependent demand this study applies the discounted cash flows dcf approach for problem analysis a heuristic approach is presented to derive the near optimal replenishment and pricing policy that tries to maximize the total net present value profit a numerical example is implemented to illustrate the theory

political bias and war we examine the incentives for countries to go to war as they depend on the comparison between how much their pivotal decision makers have at risk and how much they stand to gain from a war how this ratio compares to the country at large is what we term political bias if there is no political bias then there are always payments that one country would like to make to the other that will avoid a war in the presence of commitment or enforceability of peace treaties if there is a bias on the part of one or both countries then war can result and in some cases cannot be prevented by any transfer payments we examine how war technology and relative wealth levels interact with political bias in determining whether countries make transfers go to war and form alliances our results shed some new light on the uneven contender paradox and the interpretation of the democratic peace

some empirical dimensions of countertrade this paper discusses some of the recent theories of why countries impose countertrade obligations and compares some of the implications of these theories with data obtained from a comprehensive database of countertrade transactions

integrated inventory model for deteriorating items under a multi echelon supply chain environment abstract as the industrial environment becomes more competitive supply chain management has become essential the objective of this research is to develop a multi echelon inventory model for a deteriorating item and to derive an optimal joint total cost from an integrated perspective among the supplier the producer and the buyer a computer code is developed to derive the optimal solution a numerical example is given to illustrate the model this paper shows that the integrated approach strategy results in the lowest joint total cost as compared with the independent decision approaches

deteriorating inventory model with quantity discount pricing and partial backordering inventory models with quantity discount pricing and partial backordering although common in practice have received very little attention from researchers the objective of this study is to develop a deterministic inventory model with quantity discount pricing and partial backordering when the product in stock deteriorates with time most retailers make pricing decisions of their products at certain times of the year and these decisions affect demand in this study the demand rate is assumed to decrease as price for the product increases unlike traditional inventory models that seek to minimize cost the objective of this study is to maximize profit the findings of this study are particularly relevant to retailers of deteriorating products in a competitive environment a numerical example is given to illustrate the theory

an eoq model with partial backordering and advance payments for an evaporating item abstract in the classic economic order quantity model the purchasing cost of an order is paid at the time of its receipt in some cases retailers ask purchasers to pay all or a fraction of the purchasing cost in advance and may allow them to divide the prepayment into several equal sized parts in this paper an economic order quantity model for an evaporating item with partial backordering and partial consecutive prepayments is developed with a real case study of a gasoline station real numerical examples illustrate the proposed model and the solution method

information aggregation rationality and the condorcet jury theorem the condorcet jury theorem states that majorities are more likely than any single individual to select the better of two alternatives when there exists uncertainty about which of the two alternatives is in fact preferred most extant proofs of this theorem implicitly make the behavioral assumption that individuals vote sincerely in the collective decision making a seemingly innocuous assumption given that individuals are taken to possess a common preference for selecting the better alternative however in the model analyzed here we find that sincere behavior by all individuals is not rational even when individuals have such a common preference in particular sincere voting does not constitute a nash equilibrium a satisfactory rational choice foundation for the claim that majorities invariably do better than individuals therefore has yet to be derived

optimal production run length and warranty period for an imperfect production system under selling price dependent on warranty period abstract this paper extends the extant literature to consider that the selling price of the product sold with warranty policy is a function of the length of the warranty period for an imperfect production system a product under a free replacement repair warranty policy is considered and the lifetime distribution of the product is assumed to be exponentially distributed we seek to maximize the total profit per item through optimal determinations of the production run length and the warranty period based on the proposed mathematical model we will derive some lemmas and the propositions to carry out an efficient solution procedure to determine the optimal warranty period and production run length the numerical examples are given to illustrate the features of the proposed maximizing profit model and to show all of the possible cases of the solution procedure

voting for voters a model of electoral evolution we model the decision problems faced by the members of societies whose new members are determined by vote we adopt a number of simplifying assumptions the founders and the candidates are fixed the society operates for k periods and holds elections at the beginning of each period one vote is sufficient for admission and voters can support as many candidates as they wish voters assess the value of the streams of agents with whom they share the society while they belong to it in spite of these simplifications we show that interesting strategic behavior is implied by the dynamic structure of the problem the vote for friends may be postponed and it may be advantageous to vote for enemies we discuss the existence of different types of equilibria in pure strategies and point out interesting equilibria in mixed strategies

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

relational incentive contracts standard incentive theory models provide a rich framework for studying informational problems but assume that contracts can be perfectly enforced this paper studies the design of self enforced relational contracts i show that optimal contracts often can take a simple stationary form but that self enforcement restricts promised compensation and affects incentive provision with hidden information it may be optimal for an agent to supply the same inefficient effort regardless of cost conditions with moral hazard optimal contracts involve just two levels of compensation this is true even if performance measures are subjective in which case optimal contracts terminate following poor performance jel c73 d82 l14

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

an integrated inventory model for a single vendor and multiple buyers with ordering cost reduction abstract forming strategic alliances and utilizing modern information technologies have been the two most important ways for firms to gain such competitive advantages as lower logistics costs and secure customers loyalty in this paper we consider an integrated inventory system where a single vendor purchases and processes raw materials in order to deliver finished items to multiple buyers the vendor and all buyers are willing to invest in reducing the ordering cost e g establishing an electronic data interchange based inventory control system in order to decrease their joint total cost the amount of investment determines the planned ordering cost and hence affects their replenishment decisions one major managerial implication from this ordering cost reduction is that the efforts to streamline and speedup transactions via the application of information technologies may result in a higher degree of coordination and automation among allied trading parties an analytical model is developed to derive the optimal investment amount and replenishment decisions for both vendor and buyers the exponential ordering cost function is then applied to our general model and a numerical analysis is performed to provide interesting insights of the model numerical results show that the vendor and all the buyers can benefit directly from substantial cost savings by this ordering cost reduction investment

adjustment with a human face the role of food aid abstract major economic adjustments in third world countries have been necessary as a result of the adverse developments in the world economy in the 1980s this article discusses how food aid can help in the process of adjustment particularly in relation to the welfare of vulnerable population groups the adjustment packages of the imf and their effects on living conditions of the poor are outlined policies which constitute adjustment with a human face and the special role of food aid in supporting such policies are then described the examples of botswana and ghana are used to illustrate the use of food aid during drought and economic adjustment for governments with a commitment to protecting their vulnerable households during adjustment food aid can make a useful contribution

the production inventory problem of a product with time varying demand production and deterioration rates abstract in this paper we consider the production inventory problem in which the demand production and deterioration rates of a product are assumed to vary with time shortages of a cycle are allowed to be backlogged partially two models are developed for the problem by employing different modeling approaches over an infinite planning horizon solution procedures are derived for determining the optimal replenishment policies a procedure to find the near optimal operating policy of the problem over a finite time horizon is also suggested

self enforcing voting in international organizations some international organizations are governed by unanimity rule some others by a majority system still others have moved from one system to the other over time the existing voting models have a difficult time explaining the observed variation in governance mode and in particular the widespread occurrence of the unanimity system we present a model whose main departure from standard voting models is that there is no external enforcement mechanism each country is sovereign and cannot be forced to follow the collective decision or in other words the voting system must be self enforcing the model yields unanimity as the optimal system for a wide range of parameters and delivers rich predictions on the variation in the mode of governance both across organizations and over time we thank james anderson matt jackson francois maniquet guido tabellini and jean tirole for very helpful comments arnaud costinot provided excellent research assistance we also bene

the management of countertrade factors influencing success countertrade success was found to be higher for large firms that were experienced in exporting and in countertrade operations could accommodate countertrade takebacks and valued vertical integration exported high value high visibility complex products had a low reputation for quality and had excess capacity success was also higher if the importer valued quality had low technical proficiency was inexperienced in exporting faced barriers in export markets had a high cost of forward contracts foreign exchange constraints and faced a disequilibrium exchange rate

an inventory model with deteriorating items quantity discount pricing and time dependent partial backlogging abstract wee international journal of production economics 59 1999 511 in his interesting paper presented a deterministic inventory model with the following characteristics quantity discount schemes for the unit cost partial backlogging at a fixed rate deterioration of stock in time and demand rate being a linear function of the selling price in this article we generalize the work of wee 1999 more specifically we consider a model where the demand rate is a convex decreasing function of the selling price and the backlogging rate is a time dependent function which ensures that the rate of backlogged demand increases as the waiting time to the following replenishment point decreases

introduction food policy food aid and economic adjustment abstract in this introduction to food policy s special issue the guest editors look at the various ways in which food policy food aid and economic adjustment can interact to mutual advantage as developing countries pursue economic adjustment strategies to compensate for the unprecedented world recession concern is being expressed about the condition of poor people in low income countries and the need for adjustment with a human face with increasing amounts of aid resources being used for adjustment programmes interest has grown that food aid should also be used more purposefully to support the adjustment process

product quality market signaling and the development of east west trade countertrade a contractual form in which there is a two way flow of goods occupies a position of significance in east west trade in this paper it is shown that countertrade can solve problems which arise when the quality of eastern european products is unknown using the market signaling literature a theory is formulated in order to make predictions concerning the use of countertrade countertrade will be particularly useful when quality information is important but cannot be obtained directly and when a country has a poor quality reputation these predictions are supported by empirical tests

an optimal replenishment policy for non instantaneous deteriorating items with stock dependent demand and partial backlogging abstract in this study we consider a problem of determining the optimal replenishment policy for non instantaneous deteriorating items with stock dependent demand in the model shortages are allowed and the backlogging rate is variable and dependent on the waiting time for the next replenishment the necessary and sufficient conditions of the existence and uniqueness of the optimal solution are shown as the special cases the results for the models with instantaneous or non instantaneous deterioration rate and with or without shortages are derived further we analytically identify the best circumstance among these special cases based on the minimum total relevant cost per unit time sensitivity analysis of the optimal solution with respect to major parameters is carried out finally four numerical examples are presented to demonstrate the developed model and the solution procedure

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

countertrade and food aid in support of structural adjustment and free market transitions abstract although food aid has been advocated for countries undertaking structural adjustment policies political support for increased aid expenditures is lacking countertrade is proposed herein as a method for expanding food aid without increasing expenditures countertrade allows developing countries and the formerly centrally planned economies to accelerate growth in their export sectors while financing increased food assistance

joint economic lot size in distribution system with multiple shipment policy abstract this paper presents a new methodology to obtain the joint economic lot size in the case where multiple buyers are demanding one type of item from a single vendor the shipment policy is found and a new model is proposed to minimize the joint total relevant cost jtrc for both vendor and buyer s considering the two buyer and more than two buyer cases exact and approximate optimum solutions were obtained the benefits of the new model were illustrated in term of two different ratios production rate to demand rate and transportation cost to holding cost a sensitivity analysis was conducted to test the robustness of the new model

planning for shortages net present value analysis for a deteriorating item with partial backlogging abstract this paper develops inventory models to help answer strategic questions concerning whether planning for shortages offers financial benefits a production inventory system producing a deteriorating product in batches at a finite production rate with partial backordering is considered customers pay a deposit when placing a backorder backordered items receive a discount on the sales price as lost sales may lead to customers not returning the demand rate may depend on the fraction of lost sales we develop a cash flow based profit maximising net present value npv model without the inventory cost parameters commonly used in this context unit holding cost unit backorder cost unit deterioration cost and unit lost sales cost the model finds the optimal inventory policy just like npv models that discount the traditional parameters but has the advantage of not needing to estimate the value of the traditional parameters it is shown that in models based on discounting the traditional parameters the parameters are not exogenously determinable but are non trivial functions of non financial endogenous system parameters such as the production rate annual demand rate and backorder rate extensive numerical experiments illustrate how cash flow npv models provide insights into the value of planning for shortages and strategic choices about the design of the production inventory system it also provides insight into the classical problem of how to interpret unit backorder cost and unit lost sales cost the study indicates that these insights cannot be reliably obtained from npv models based on discounting unit backorder costs and unit lost sales costs

the joint economic lot size problem a review abstract this article reviews lot size models which focus on coordinated inventory replenishment decisions between buyer and vendor and their impact on the performance of the supply chain these so called joint economic lot size jels models determine order production and shipment quantities from the perspective of the supply chain with the objective of minimizing total system costs this paper first describes the problem studied introduces the methodology of the review and presents a descriptive analysis of the selected papers subsequently papers are categorized and analyzed with respect to their contribution to the coordination of different echelons in the supply chain finally the review highlights gaps in the existing literature and suggests interesting areas for future research

two warehouse partial backlogging inventory models with three parameter weibull distribution deterioration under inflation abstract in many inventory systems the effects of deterioration of physical goods have drawn much attention of various researchers in recent years the more the deterioration is the more the order quantity would be according to such consideration taking the deterioration rate into account is necessary thus in this paper i develop the two warehouse partial backlogging inventory model introduced in yang 2006 to incorporate three parameter weibull deterioration distribution the objective is to derive the optimal replenishment policy that minimizes the net present value of total relevant cost per unit time two alternative models are compared based on the minimum cost approach the study shows that the optimal solution not only exists but also is unique model 2 is still less expensive to operate than model 1 in the proposed model finally some numerical examples and sensitivity analysis on parameters are made to validate the results of the proposed inventory system

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

a survey of deterministic models for the eoq and epq with partial backordering models for the basic deterministic eoq or epq problem with partial backordering or backlogging make all the assumptions of the classic eoq or epq model with full backordering except that only a fraction of the demand during the stockout period is backordered in this survey we review deterministic models that have been developed over the past 40 years that address the basic models and extensions that add other considerations such as pricing perishable or deteriorating inventory time varying or stock dependent demand quantity discounts or multiple warehouses

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