how to set minimum acceptable bids with an application to real estate auctions in a general auction model with affiliated signals common components to valuations and endogenous entry we compute the equilibrium bidding strategies and outcomes and derive a lower bound on the optimal reserve price this lower bound can be computed using data on past auctions combined with information about the subsequent sales prices of unsold goods we illustrate how to compute the lower bound using data from real estate auctions

on the optimality of joint ordering policies in a multi product dynamic lot size model with individual and joint set up costs abstract this paper considers a deterministic dynamic multi product lot size model with individual and joint set up costs the computational effort required by dynamic programming algorithms for finding simultaneously optimal multi product ordering policies particularly increases exponentially with the number of products it is possible to crack up this exponential dependence of computational requirements on the number of products if joint ordering of several products is optimal it is the aim of the present paper to give conditions for the optimality of joint ordering policies particular attention is given to the usefulness of joint ordering results in simplifying computations

single period multiproduct inventory models with substitution we study a single period multiproduct inventory problem with substitution and proportional costs and revenues we consider n products and n demand classes with full downward substitution i e excess demand for class i can be satisfied using product j for i j we first discuss a two stage profit maximization formulation for the multiproduct substitution problem we show that a greedy allocation policy is optimal we use this to write the expected profits and its first partials explicitly this in turn enables us to prove additional properties of the profit function and several interesting properties of the optimal solution in a limited computational study using two products we illustrate the benefits of solving for the optimal quantities when substitution is considered at the ordering stage over similar computations without considering substitution while ordering specifically we show that the benefits are higher with high demand variability low substitution cost low profit margins or low price to cost ratio high salvage values and similarity of products in terms of prices and costs

continuity in auction design abstract j cremer and r p mclean econometrica56 1988 1247 1257 have shown that the auctioneer can extract all the surplus when the private valuations of bidders are not statistically independent the paper shows that this result does not necessarily arise under limited liability or risk aversion under limited liability and or risk aversion we prove that the functions corresponding to the auctionner s optimal expected gain and to the maximum total surplus are continuous in the space of possible information distributions thus by continuity the auctioneer wil not be able to extract all the rents when bidders private valuations are approximately independent

optimal inventory policies when ordering prices are random we consider a single item inventory model with deterministic demands at the beginning of each period a random ordering price is received according to a known distribution function a decision must be made as to how much if any of the item to order in each period so as to minimize total expected costs while satisfying all demands we show that in each period a sequence of critical price levels determines the optimal ordering strategy so that it is optimal to satisfy the demands of the next n periods if and only if the random price falls between the nth and the n 1st levels we derive recursive expressions that describe the critical price numbers and demonstrate the relationship of these expressions to minimal expected cost we study finite horizon as well as infinite horizon models and show that the critical number strategy is also average cost optimal

the design of multidimensional auctions procurement auctions usually require the bid to specify several characteristics of the contract to be fulfilled in this article i study the design of such mechanisms allowing for a special case of correlation of the firm s costs i describe the properties of optimal mechanisms and study the design of multidimensional auctions contrary to the independent costs model to implement the optimal outcome the procurer will need to use a two stage auction in the first stage the procurer selects one firm in the second stage he bargains to readjust the level of quality to be provided

parametric analysis of setup cost in the economic lot sizing model without speculative motives in this paper we consider the important special case of the economic lot sizing problem in which there are no speculative motives to hold inventory we analyze the effects of varying all setup costs by the same amount this is equivalent to studying the set of optimal production periods when the number of such periods changes we show that this optimal set changes in a very structured way this fact is interesting in itself and can be used to develop faster algorithms for such problems as the computation of the stability region and the determination of all efficient solutions of a lot sizing problem furthermore we generalize two related convexity results which have appeared in the literature

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

a comparison of simple heuristics for multi product dynamic demand lot sizing with limited warehouse capacity abstract the paper analyzes the problem of the replenishment of multiple products to satisfy dynamic demands when the warehouse capacity or the available inventory budget is limited in this context the timing of replenishment lot sizes has to be staggered to account for the capacity conflict and to provide an effective space sharing in addition to the solution of the trade off between setup and inventory holding costs we analyze three simple heuristics first we review a forward algorithm that successively builds lots by extending replenishments according to a cost based priority rule the second heuristic solves the lot sizing problems independently for each product in a first step and then resolves capacity violations by a smoothing mechanism further this paper adapts a heuristic for single item uncapacitated lot sizing that successively improves an initial lot for lot schedule by combining replenishments according to a cost savings based priority rule to the multi item capacitated problem the performance of the three simple methods is compared in an extensive numerical study and benchmarked against the solution of a mixed integer programming approach the results show the different ability of the approaches to simultaneously account for the individual lot sizing problems and the lot staggering problem across multiple products especially the savings approach appears to provide better results for a broad range of problems especially for large tightly capacitated problems with high demand variability

the relationship between relative prices and the general price level it is very nearly a truismi amaong neoclassical economists that the public is wont to confuse changes in the general price level with relative price changes correspondingl y one might speak of the independence between the two as one of the central postulates of the neoclassical tradition william stanley jevons was aml ong the first to identify this basic dichotomin economic life as well as to attempt to explain the ordinary citizen s seenming incapacity to understand it

a capacitated single item lot size model abstract wagner and whitin s inventory model is generalized to incorporate a limited production rate the model is conspicuous amongst related models in the literature as wagner and whitin s original algorithm may be applied the result requires restrictions on the cost coefficients that make conventional material requirements planning the model s natural field of application

the single item uncapacitated lot sizing problem with time dependent batch sizes np hard and polynomial cases abstract this paper considers the uncapacitated lot sizing problem with batch delivery focusing on the general case of time dependent batch sizes we study the complexity of the problem depending on the other cost parameters namely the setup cost the fixed cost per batch the unit procurement cost and the unit holding cost we establish that if any one of the cost parameters is allowed to be time dependent the problem is np hard on the contrary if all the cost parameters are stationary and assuming no unit holding cost we show that the problem is polynomially solvable in time o t 3 where t denotes the number of periods of the horizon we also show that in the case of divisible batch sizes the problem with time varying setup costs a stationary fixed cost per batch and no unit procurement nor holding cost can be solved in time o t 3 log t

the single item lot sizing problem with immediate lost sales abstract we introduce a profit maximization version of the well known wagner whitin model for the deterministic uncapacitated single item lot sizing problem with lost sales demand cannot be backlogged but it does not have to be satisfied either costs and selling prices are assumed to be time variant differentiating our model from previous models with lost sales production quantities and levels of lost sales in different periods represent a twofold decision problem we first transform the total profit function into a special total cost function we then prove several properties of an optimal solution a forward recursive dynamic programming algorithm is developed to solve the problem optimally in o t 2 time where t denotes the number of periods in the problem horizon the proposed algorithm can solve problems of sizes up to 400 periods in less than a second on a 500 mhz pentium iii processor

aggregate sources of relative price variability among agricultural commodities a measure of relative price variability among forty seven agricultural commodities is developed for the period 1962 to 1987 econometric models are used to explore the effects of macroeconomic instability on relative price variability within the agricultural sector the results show that these relative prices are more variable when actual and unanticipated inflation rates are higher they may also be more variable during periods when real shocks to the macroeconomy are relatively large thus monetary and fiscal events are not neutral with respect to the agricultural sector because macroeconomic instability appears to create instability and increased uncertainty in agricultural markets

production strategies for a stochastic lot sizing problem with constant capacity abstract this paper presents a single item capacitated stochastic lot sizing problem motibated by a dutch company operating in a make to order environment due to a highly fluctuating and unpredictable demand it is not possible to keep any finished goods inventory in response to a customer s order a fixed delivery date is quoted by the company the objective is to determine in each period of the planning horizon the optimal size of production lots so that delivery dates are met as closely as possible at the expense of minimal average costs these include set up costs holding costs for orders that are finished before their promised delivery date and penalty costs for orders that are not satisfied on time and are therefore backordered given that the optimal production policy is likely to be too complex in this situation attention is focused on the development of heuristic procedures in this paper two heuristics are proposed the first one is an extension of a simple production strategy derived by dellaert 5 for the uncapacitated version of the problem the second heuristic is based on the well known silver meal algorithm for the case of deterministic time varying demand experimental results suggest that the first heuristic gives low average costs especially when the demand variability is low and there are large differences in the cost parameters the silver meal approach is usually outperformed by the first heuristic in situations where the available production capacity is tight and the demand variability is low

common value auctions with discrete private information abstract a first price sealed bid common value auction with finite valued conditionally independent private information is studied we show that the equilibrium in this auction game is characterized by all bidders using a symmetric mixed strategy in which bids are randomized over intervals that are successive and non overlapping for consecutively indexed signals we also show that as the number of bidders grows the winning bid conditional on the true value of the object converges to a non degenerate random variable that is affiliated with the true value therefore only partial information revelation is achieved in the limit

a dynamic mechanism and surplus extraction under ambiguity we study the question of auction design in an ipv setting characterized by ambiguity we assume that the preferences of agents exhibit ambiguity aversion in particular they are represented by the epsilon contamination model we show that a simple variation of a discrete dutch auction can extract almost all surplus this contrasts with optimal auctions under ipv without ambiguity as well as with optimal static auctions with ambiguity in all of these types other than the lowest participating type obtain a positive surplus an important point of departure is that the modified dutch mechanism is dynamic rather than static establishing that under ambiguity aversion even when the setting is ipv in all other respects a dynamic mechanism can have additional bite over its static counterparts a further general insight is that the standard revelation principle does not automatically extend to environments not characterized by subjective expected utility

designing a private industry government auctions with endogenous market structure abstract this paper considers government mechanisms for auctioning production rights in which both the winners and the market structure doupoly dual sourcing monopoly sole sourcing or government owned production are a function of the bids in designing the optimal mechanism the government considers the tradeoffs among consumer surplus producer surplus and revenue under incomplete information doupoly is implemented less frequently and government production more frequently than under complete information when bidders are symmetric the optimal mechanism can be implemented as a modified second price auction applications to privatization deregulation and defense procurement are discussed

information management in incentive problems we extend the standard procurement model to examine how an agent is optimally induced to acquire valuable planning information before he choose an unobservable level of cost reducing effort concer

simulation based sequencing and lot size optimisation for a production and inventory system with multiple items abstract we investigate the following decision problem a manufacturing unit has to meet a random demand for n items at the same time only one item can be manufactured manufacturing times are random whereas set up times are known positive constants but different for different items finished production is stored in a warehouse with finite capacity the availability of raw material is always guaranteed demand that cannot be satisfied by items in the warehouse will be backordered in a queue with given capacity demand that meets a full backorder queue is lost we assume cost for manufacturing items for production switches for holding items in the warehouse for waiting and lost demand for sold items a given reward is earned the problem now is to define such a manufacturing policy i e a sequencing rule and a lot size rule which maximises the expected profit per time unit since that problem is too complex for an analytical solution we restrict our search for an optimal policy to simple structured policies which can be described by a few parameters to find optimal parameter values we use simulation optimisation where a simulator for the system is combined with a genetic algorithm as an optimiser the paper is finished with some numerical examples to show the applicability of the proposed approach

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

the single product lot sizing problem with constant parameters and backlogging exact results a new solution and all parameter stability regions we consider the single product lot sizing problem over a finite planning horizon demand at each period is constant and excess demand is completely backlogged holding and backlogging costs are proportional to the amount of inventory stocked or backlogged while ordering cost is fixed independent of the quantity ordered the optimal policy targets to minimize the total relevant costs over the planning horizon the key results of this paper are 1 an explicit formula for the optimal total cost as a function of the model parameters and the number of cycles of the policy 2 a new polynomial time algorithm which determines the overall optimal policy and 3 stability regions for any solution considering simultaneous variations on all cost and demand parameters the proposed algorithm is easy to implement and therefore is suitable for practical use

multi product lot sizing with a transportation capacity reservation contract abstract although transportation costs can form more than 50 of the total logistics costs of a product they are often neglected in lot sizing research and modelling nonetheless the body of research that does take transportation costs into account is gradually growing the bulk of this type of research however assumes that freight rates decrease as shipping weights and or volumes increase inspired by the situation with a large european manufacturing company we study a multi product lot sizing model where in any period any portion of a reserved transportation capacity can be used in exchange for a guaranteed price if the capacity is insufficient then the shipper needs to contract additional transportation capacity on the spot market where the prevailing price is higher accordingly the freight rates are piece wise linearly increasing in our model we prove that the problem of determining transportation lot sizes so as to meet warehouse demand with no backlogging allowed and to minimize total costs that is the sum of inventory carrying ordering and transportation costs is np hard in the strong sense furthermore we present a lagrangean relaxation algorithm to compute lower and upper bounds of which comprehensive computational experiments show the compelling performance in terms of quality and speed

economic instability in agriculture the contributions of prices government programs and exports in the first edition of foundations of farm policy 1970 p 343 i stated that the major long term problem of commercial farms is not labor mobility low resource returns or low income but rather is instability sources of instability have been traced to domestic macroeconomic policies by schultz to exchange rates by schuh and to each of those and farm output by firsh serious gaps remain in our knowledge of sources of instability however the purpose of this paper is to estimate sources of instability in u s farm income over time with special attention to the role of prices exports and government payments and commodity programs variation in production and utilization provide estimates of statistically appropriate stocks in aggregate and for feed grains soybeans and wheat

bidding behavior given point and interval values in a second price auction abstract although rational choice theory presumes people have a point estimate of their willingness to pay wtp for a good or service the idea of coherent arbitrariness suggests they have an interval of values herein we explore bidding behavior in a second price auction in which bidders have point or interval values and point or interval bidding we find bidders bid rationally i when bidders have a point value but are asked to state an interval bid they choose to bid as an interval with the point value as the mean of the interval ii bidders who had a value interval but are asked to bid as a point estimate bid the expected value from the interval and iii bidders with an interval value and who bid an interval such that expected bids equate expected values

approximation algorithms for deterministic continuous review inventory lot sizing problems with time varying demand this work deals with the continuous time lot sizing inventory problem when demand and costs are time dependent we adapt a cost balancing technique developed for the periodic review version of our problem to the continuousreview framework we prove that the solution obtained costs at most twice the cost of an optimal solution we study the numerical complexity of the algorithm and generalize the policy to several important extensions while preserving its performance guarantee of two finally we propose a modified version of our algorithm for the lot sizing model with some restricted settings that improves the worst case bound

optimal pricing mechanisms with unknown demand the standard profit maximizing multi unit auction intersects the submitted demand curve with a preset reservation supply curve which is determined using the distribution from which the buyers valuations are drawn however when this distribution is unknown a preset supply curve cannot maximize monopoly profits the optimal pricing mechanism in this situation sets a price to each buyer on the basis of the demand distribution inferred statistically from other buyers bids the resulting profit converges to the optimal monopoly profit with known demand as the number of buyers goes to infinity and convergence can be substantially faster than with sequential price experimentation

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

correlated information mechanism design and informational rents abstract cremer and mclean econometrica 56 1988 1247 1258 obtain a sufficient and necessary condition for full surplus extraction in bayesian nash equilibrium the rank condition which mcafee and reny econometrica 60 2 1992 395 421 later generalize for continuous type spaces this paper shows that if the principal does not know how noisy is the agent s signal or equivalently when signals available to an agent can be ranked by blackwell s informativeness and an agent s informativeness is independent of others information the rank condition fails to hold conversely when rank condition fails and informational rents are left to an agent the model can be interpreted as if the principal were uncertain about the informativeness of the agent s signal

implications of the macroeconomic outlook for agriculture this paper analyzes the implications for agriculture of the macroeconomic scenarios put forth by bosworth and lawrence a substantial body of work in recent years has developed both the theoretical framework and empirical evidence on the channels of influence between the macroeconomy and agriculture the aaea sponsored preconference workshop this year entitled value of large scale aggregate models for economic policy analysis manifests the profession s interest in quantifying the effects that macroeconomic factors have upon the economic performance and financial health of agriculture this paper draws upon the findings of previous work in general terms but more specifically we present the agricultural implications of two alternative macroeconomic environments implied by an existing macroeconomic model which emphasizes agriculture s interface with the macroeconomy the second section of this paper reviews the major findings of the literature on transmission mechanisms linking agriculture with the general economy the third section provides key details of how agriculture fares under bosworth and lawrence s outlook for the general economy through 1990 including the implications for farm prices cash receipts wealth and financial stress the fourth section discusses the consequences of one potential deviation from bosworth and lawrence s out

ending inventory valuation in multiperiod production scheduling when making lot sizing decisions managers often use a model horizon t that is much smaller than any reasonable estimate of the firm s future horizon this is done because forecast accuracy deteriorates rapidly for longer horizons while computational burden increases however what is optimal over the short horizon may be suboptimal over the long run resulting in errors known as end effects a common end effect in lot sizing models is to set end of horizon inventory to zero this policy can result in excessive setup costs or stock outs in the long run we present a method to mitigate end effects in lot sizing by including a valuation term vit for end of horizon inventory it in the objective function of the short horizon model we develop this concept within the classical eoq modeling framework and then apply it to the dynamic lot sizing problem dlsp if demand in each period of the dlsp equals the long run average demand rate then our procedure induces an optimal ordering policy over the short horizon that coincides with the long run optimal ordering policy we test our procedure empirically against the wagner whitin algorithm and the silver meal heuristic under several demand patterns within a rolling horizon framework with few exceptions our approach significantly outperforms the other approaches tested for modest to long model horizons we discuss applicability to more general lot sizing problems

production inventory games a new class of totally balanced combinatorial optimization games in this paper we introduce a new class of cooperative games that arise from production inventory problems several agents have to cover their demand over a finite time horizon and shortages are allowed each agent has its own unit production inventory holding and backlogging cost cooperation among agents is given by sharing production processes and warehouse facilities agents in a coalition produce with the cheapest production cost and store with the cheapest inventory cost we prove that the resulting cooperative game is totally balanced and the owen set reduces to a singleton the owen point based on this type of allocation we find a population monotonic allocation scheme for this class of games finally we point out the relationship of the owen point with other well known allocation rules such as the nucleolus and the shapley value

relative agricultural prices and monetary policy an imperfect information rational expectations model of relative price determination is presented this model provides an econometric specification for testing for a causal relationship between money and the relative prices of agricultural commodities test results indicate that variations in the growth rate of the nominal money supply whether anticipated or unanticipated have not been an important influence on the average level of prices received by farmers relative to other prices in the economy over the period 1951 85

analytical evaluation of heuristics performance for the single level lot sizing problem for products with constant demand abstract in this paper we examine the performance of several commonly used heuristics for the single level lot sizing problem for products with stationary demand and cost parameters a particular combination of demand and cost combination introduced by blackburn and millen called the lot sizing index lsi is shown to be an excellent predictor of heuristics performance for any finite horizon problem the importance of the lsi as a performance predictor is established through an analysis of the heuristics objective function and the optimal cost function

the impact of inflation on the real income of u s farmers according to conventional economic theory an unanticipated increase in the rate of general price inflation benefits those whose money incomes are flexible at the expense of those whose money incomes are fixed farmers have flexible money incomes hence theory suggests that farmers should benefit from an unanticipated increase in the rate of inflation yet at least for recent time periods empirical studies have not found that farmers gain real income as a result of an increase in the rate of general price inflation for example tweeten concluded that the terms of trade for farmers deteriorates improves as the rate of inflation rises falls this conclusion was based on his empirical finding that as inflation increases prices paid by farmers increase faster than the prices they receive on the other hand studies by gardner prentice and schertz and chambers found no significant effects of inflation on farmers terms of trade in this paper we examine various measures of relative prices over different time periods to test the hypothesis suggested by economic theory that farmers are benefitted by an acceleration in the rate of general price inflation and conversely are harmed by a deceleration in the inflation rate the real income of farmers is equal to the sum of the physical quantities which they produce multiplied by the money prices they receive all then divided by the general price level here we ignore changes in the physical production of farmers and concentrate on the behavior of the prices they receive for this physical production relative to the behavior of other prices we assume that if the prices farmers receive for their physical production rise fall relative to other prices the economic well being of farmers is enhanced diminished

operations research in inventory management a review and critique the objectives of inventory management including the relevant related costs are examined in this paper a brief review of standard problems that have been effectively solved is presented however we point out that a serious gap exists between theory and practice in many organizations suggestions are made for bridging this gap finally a list is provided of a number of research problems whose implementable solution would have a major beneficial impact on the practice of inventory management

requirements planning with pricing and order selection flexibility past requirements planning research has typically assumed that the firms demands are determined prior to production planning in contrast we explore a single stage planning model that implicitly decides through pricing decisions the demand levels the firm should satisfy in order to maximize contribution to profit we briefly discuss solution methods and properties for these problems when production capacities are unlimited the key result of this work is a polynomial time solution approach to the problem under time invariant finite production capacities and piecewise linear and concave revenue functions in price

agricultural and financial market interdependence in the short run a theoretical model capable of examining the effects of various monetary policies on agriculture is developed results from comparative static experiments with the model show that a restrictive monetary policy may adversely affect agriculture results from the theoretical model are compared with earlier studies and are empirically investigated using vector autoregression techniques in general empirical analysis supports the theoretical developments

dynamic lot sizing models with pricing for new products while previous dynamic lot sizing dls models mainly consider mature products this study analyzes production planning decisions for new products the demand dynamics caused by new product diffusion complicate production decisions for new products we integrate dls and discrete bass models to provide optimal decisions for pricing and production planning problems moreover we study the joint influence of product diffusion and pricing parameters on the dls decisions this leads to the following insights first coordinated production pricing and dynamic pricing improve profitability second the optimal pricing strategy is affected by market conditions the penetration pricing strategy outperforms the skimming pricing strategy when consumers are less sensitive to relative price changes than to the introductory price when the product diffuses slowly or when the consumer initiative level is low otherwise the latter outperforms the former finally pricing strategies and product diffusion patterns reshape the cost structure of a firm coordinated decisions and dynamic pricing strategy substantially reduce the cost revenue ratio whereas an increase in the consumer initiative level or product diffusion speed can improve cost efficiency

dynamic lot sizing with batch ordering and truckload discounts this paper studies two important variants of the dynamic economic lot sizing problem that are applicable to a wide range of real world situations in the first model production in each time period is restricted to a multiple of a constant batch size where backlogging is allowed and all cost parameters are time varying several properties of the optimal solution are discussed based on these properties an efficient dynamic programming algorithm is developed the efficiency of the dynamic program is further improved through the use of monge matrices using the results developed for the first model an o n3log n algorithm is developed to solve the second model which has a general form of product acquisition cost structure including a fixed charge for each acquisition a variable unit production cost and a freight cost with a truckload discount this algorithm can also be used to solve a more general problem with concave cost functions

relative prices and money a vector autoregression on brazilian data recent data on brazilian agricultural prices industrial prices and money supply are analyzed in a vector autoregression the empirical findings show strong one way granger type causality from money supply to agricultural prices while feedback is observed between industrial prices and money supply under the usual monetarist ordering of contemporaneous innovation covariance agricultural prices do not adjust faster than industrial prices to a shock in the money supply

an investigation of the effect of monetary factors on agriculture abstract this paper uses an econometric model to assess some of the effects of macro monetary factors on u s agricultural markets attention is focused on impacts of decreasing increasing the level of domestic credit on agricultural trade prices inventory accumulation and domestic disappearance results show that tight monetary policy lowers prices and increase demand for domestic agriculture however the upward pressure on the exchange rate seriously deteriorates the position of u s exports in international markets

production allocation with dual provisioning abstract consider a manufacturer that has existing in house capacity to produce certain products however due to recent growth in demand the existing capacity is insufficient to meet the total requirements over a finite planning horizon as a short term solution the manufacturer has decided to order part of the total requirements from an external supplier this paper presents a model that focuses on the issue of allocating a production quantity among the in house facility and an external supplier we construct a product allocation problem that determines an optimal allocation so that the total relevant cost in house production cost ordering cost etc is minimized in addition we analyze the complexity of the problem and develop two different lagrangian heuristics for generating near optimal allocations

on the power of macroeconomic linkages to explain events in u s agriculture the significance for agriculture of macroeconomic events in the 1980s depends upon what elements in the macroeconomy are most strongly linked to agriculture and how these linkages function it is idle to say for example that inflation poses particularly serious problems for agriculture in the 1980s unless we have evidence that inflation generally causes particularly serious problems for agriculture this paper concentrates on the past literature and current state of evidence on such questions the final section considers the possibility of scientifically defensible forecasts for the 1980s it is short

lot sizing for products with finite demand horizon and periodic review inventory policy abstract this paper analyzes and develops an efficient algorithm for solving a simple generalization of the classical economic order quantity eoq model where the demand horizon is finite and a periodic review inventory policy is followed such problems could arise in production shops where the product under consideration is going to be discontinued and or replaced by some other product after a certain known number of periods such problems could also arise as subproblems in large prodution inventory problems were demand rate is constant in some periods and varying in others

dynamic lot sizing when demand timing is uncertain we characterize optimal solutions for the dynamic lot sizing problem when demand quantities are known but their timing is uncertain the characterization states that for some possible history of demands following a period of production there is a period with zero inventory before another period with production using this characterization we outline a dynamic program for the solution of these problems some results from sample problems illustrate the variety of optimal solutions that can occur

neutrality of inflation in the agricultural sector abstract the paper considers the effect of inflation on the relative prices of products traded in auction markets prices of us agricultural products are used for the period 1951 1981 since agricultural products are widely traded the real forces of supply and demand specific to agriculture are represented by foreign agricultural prices the exchange rate is entered as a separate variable influencing domestic agricultural prices trade between the usa and the ten countries included in the federal reserve board s trade weighted dollar is considered the empirical results are consistent with the hypothesis that inflation did not alter relative agricultural prices when the real forces of supply and demand and the exchange rate are held constant

note a note on the dynamic lot size model with uncertainty in demand and supply processes in this paper we give some extensions of a result of nevison and burstein nevison c h m burstein 1984 the dynamic lot size model with stochastic lead times management sci 30 100 109 who discuss a dynamic lot sizing model with stochastic lead times they consider a situation in which the lead time distribution is unaltered by the amount which is ordered but is otherwise arbitrary and characterize the optimal solution in terms of points at which there is zero inventory here we give a more precise characterization and show that these results can be extended to a situation in which the demands are also stochastic and in which there is uncertainty relating to quantity as well as to the timing of demands and order arrivals the method of proof that we use is different from that used by nevison and burstein

an approach to evaluate the impact of interaction between demand forecasting method and stock control policy on the inventory system performances abstract usually in stock control studies demand data are considered as an input to the model without explicitly considering that they are the results of a demand forecasting system stock control system is examined independently of the demand forecasting system and it is assumed that demand data or forecast errors have been properly modelled however the interactions that may exist between demand forecasting methods and stock control systems in terms of their effects on global system performances are not considered in the paper an approach for evaluating these interactions based on a comparative simulation test of global system costs using historical data is presented the approach is explained through a real case the replenishment from different suppliers of a central depot of tinned food which supplies more than 700 items to warehouses at the lower echelon results of the simulation study show that traditional measures of forecast errors cannot be taken as sole indicators for the choice among different demand forecasting methods these methods on the contrary have to be evaluated on the basis of total costs and service level of the global inventory control system

pricing and manufacturing decisions when demand is a function of prices in multiple periods in most deterministic manufacturing decision models demand is either known or induced by pricing decisions in the period that the demand is experienced however in more realistic market scenarios consumers make purchase decisions with respect to price not only in the current period but also in past and future periods we model a joint manufacturing pricing decision problem accounting for that portion of demand realized in each period that is induced by the interaction of pricing decisions in the current period and in previous periods we formulate a mathematical programming model and develop solution techniques we identify structural properties of our models and develop closed form solutions and effective heuristics for various special cases of our models finally we conduct extensive computational experiments to quantify the effectiveness of our heuristics and to develop managerial insights

auctions versus negotiations which is the more profitable way to sell a company an auction with no reserve price or an optimally structured negotiation with one less bidder we show under reasonable assumptions that the auction is always preferable when bidders signals are independent for affiliated signals the result holds under certain restrictions on the seller s choice of negotiating mechanism the result suggests that the value of negotiating skill is small relative to the value of additional competition the paper also shows how the analogies between monopoly theory and auction theory can help derive new results in auction theory jel d44 g34 there are close analogies between standard price theory and the theory of auctions in an absolute english auction in which the price rises continuously until only one bidder remains and the seller is required to accept the final bid the sale price equals the lowest competitive price at which supply equals demand in the theory of optimal auctions the seller is treated as a monopolist who can choose any

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

computing core allocations in cooperative games with an application to cooperative procurement abstract cooperative game theory defines several concepts for distributing outcome shares in a cooperative game with transferable utilities one of the most famous solution concepts is the core which defines a set of outcome allocations that are stable such that no coalition has an incentive to leave the grand coalition in this paper we propose a general procedure to compute a core element or to detect that no core allocation exists which is based on mathematical programming techniques the procedure proposed in this paper can be applied to a wide class of cooperative games where the characteristic function is given by the optimum objective function value of a complex optimization problem for cooperative procurement which is an example from the field of supply chain management where some literature on the core concept already exists we prove the applicability and provide computational results to demonstrate that games with 150 players can be handled

robust economic order quantity models abstract in this paper we study the classical economic order quantity eoq model under significant in particular the problem under consideration is the economic order quantity model with the input data of the demand rate the order cost and the holding cost rate being uncertain a robustness approach based on scenario characterization of the input data is adopted to describe the uncertainties the aim of the approach is to find an inventory policy that performs well under all realizable input data scenarios an efficient linear time algorithm is devised to find the robust decisions analytical results are obtained for the case where input data are defined in continuous intervals comparisons on performances between the robust decisions and the stochastic optimization decisions are conducted the results demonstrate the advantages of robustness approach

a master production scheduling procedure for stochastic demand and rolling planning horizons abstract the problem of interest is a one product uncapacitated master production schedule mps in which decisions are made under rolling planning horizons demand is stochastic and time varying and effectiveness is measured by inventory holding production setup and backorder costs typically in both the research literature and the business practice the stochastic nature of the problem is modeled in an ad hoc fashion the stochastic mps problem is usually solved by adding safety stock to production quantities obtained from a deterministic lot sizing algorithm here the stochastic nature of the problem is explicitly considered as an optimal algorithm for solving the static probabilistic dynamic lot sizing problem is adapted to rolling planning horizons the resulting algorithm is found to dominate traditional approaches over a wide variety of experimental factors reducing total costs by an average of 16 over traditional methods

the bidder exclusion effect we introduce a new simple to compute test of independence of valuations and the number of bidders for ascending button auctions with symmetric conditionally independent private values the test involves estimating the expected revenue drop from excluding a bidder at random which can be computed as a scaled sample average of a difference of order statistics this object also provides a bound on counterfactual revenue changes from optimal reserve pricing or bidder mergers we illustrate the approach using data from timber auctions where we find some evidence that bidder valuations and the number of participants are not independent

an analysis of the war of attrition and the all pay auction we study the war of attrition and the all pay auction when players signals are affiliated and symmetrically distributed we a find sufficient conditions for the existence of symmetric monotonic equilibrium bidding strategies and b examine the performance of these auction forms in terms of the expected revenue accruing to the seller under our conditions the war of attrition raises greater expected revenue than all other known sealed bid auction forms journal of economic literature classification numbers d44 d82 1997 academic press

infinite horizon production planning in time varying systems with convex production and inventory costs we consider the planning of production over the infinite horizon in a system with time varying convex production and inventory holding costs this production lot size problem is frequently faced in industry where a forecast of future demand must be made and production is to be scheduled based on the forecast because forecasts of the future are costly and difficult to validate a firm would like to minimize the number of periods into the future it needs to forecast in order to make an optimal production decision today in this paper we first prove that under very general conditions finite horizon versions of the problem exist that lead to an optimal production level at any decision epoch in particular we show it suffices for the first period infinite horizon production decision to solve for a horizon that exceeds the longest time interval over which it can prove profitable to carry inventory we then develop a closed form expression for computing such a horizon and provide a simple finite algorithm to recursively compute an infinite horizon optimal production schedule

the profit maximizing capacitated lot size pclsp problem this paper extends the results for capacitated lot sizing research to include pricing based on a few examples the new version appears to by much easier to solve computationally the paper by including price can modify demand as well as production schedule due to model assumptions form of demand a feasible solution can be found easily unlike clsp