optimal time based consolidation policy with price sensitive demand abstract we consider a single item inventory system where shipments are consolidated to reduce the transportation cost using a time based consolidation policy and develop a mathematical model to obtain the optimal price replenishment quantity and dispatch cycle to maximize the total profit the long run average profit is computed and the optimality properties are obtained using the optimality properties we develop an efficient algorithm to obtain the optimal values of price replenishment quantity and dispatch cycle for the proposed policy we then extend our results to consider quantity discount of unit dispatch cost in order to compare the performances of the proposed policy with the optimal quantity based policy extensive numerical experiments are conducted and the total profit and the customer waiting time that represents quality of service are compared we also propose the quantity time based policy which is a hybrid approach and the numerical results show that additional profit can be obtained without sacrificing quality of service

let s not throw the baby out with the bath water the role of urban villages in housing rural migrants in china in the era of china s economic growth and urbanisation providing adequate and affordable housing for rural urban migrants in urban areas is crucial for the success of china s multifaceted reforms

an economic order quantity model with partial backordering and all units discount abstract the classic economic order quantity model assumes that the unit purchasing cost is not based on the order quantity in practice a supplier may offer purchasers an all units discount we develop a model and solution procedure for the eoq with all unit discounts and partial backordering at a constant rate we show and illustrate with a numerical example how that model can be used to find the solution for the eoq with discount and full backordering a multi factor experiment is used to gain insights into the improvement in performance of the proposed procedure relative to using the basic eoq or the eoq with full backordering and to identify the model parameters that have the greatest impact on the model s performance

measuring productivity in economic growth since world war ii the improvement in the material well being of their citizens has been an explicit goal of nearly every nation associated with this goal is the challenge of how to utilize primary resources more efficiently to get more from what goes into the productive process success in this endeavor requires that the economic processes be in continual disequilibrium which gives rise to opportunities that decision makers can use to advan

evaluating returns to agricultural research a review this paper reviews and compares the most common approaches used to evaluate public agricultural research investment ex post studies fall into two major groups a consumer and producer surplus analyses estimating average rates of return to research and b production function analyses estimating marginal rates of return to research ex ante studies fall into four groups a those using scoring models to rank research activities b those employing benefit cost analysis to establish rates of return to research c those using simulation models and d those using mathematical programming to select an optimal mix of research activities

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

a classification of literature on determining the lot size under quantity discounts abstract determining a lot size in the presence of either all units or incremental discounts has represented one of major interests of materials managers it is a common practice that the suppliers offer quantity discount to entice the buyers to purchase more and to achieve economies of scale for transportation and processing costs this paper will classify the literature on lot sizing determination under several types of discount schemes and discuss some of the significant literature in this area over two decades also some future research areas have been identified

the alternative funding of agricultural economics research the experience of the past decade and challenge to the profession christensen and robinson carefully document the relative decline in federal funding support for economics research in the state agricultural experiment stations saes within the category of federal funding they note the sharp erosion of support from csrs sources relative to that provided by usda cooperative grants and agreements and by allocations from other federal non usda agencies the obvious implication is that alternative nonfederal sources have become of increasing importance to the funding of economics research programs in saes institutions the central question is whether the relative shifts in funding sources might have an impact on the research contributions of individuals and departments and if so might the impact be for the better or for the worse it is unlikely that there is a generalizable valid response to the query yet it may justly deserve our serious consideration for it is not difficult to accept the general notion that shifting sources of research support are likely to have exerted incremental changes in research agendas and in the kind of research that is now supportable in departments of agricultural economics in the mid 1980s and should the trends continue the forces in motion might seriously influence how we go about meeting the substantive research challenges of the 1990s this paper seeks to establish some albeit a quite limited basis for further discussion by examining selected aspects of recent changes in support for economics research and by providing initial comments on alternative funding opportunities and on challenges for agricultural economists and for programs of agricultural economics research changes in economics research funding 1971 73 to 1981 83

commuting congestion and employment dispersal in cities with mixed land use abstract for centuries cities have been modeled as having centered employment scarce access to which generates land rent this paper first presents some new empirical evidence that in us cities actual employment turns out to be almost as dispersed as residences this range of urban forms is generated with analytic ease in a model that assumes land can have mixed rather than exclusive use at any location the model has firms trading off a central agglomeration force against the lower wages that accompany shorter commuting distances in peripheral locations at one extreme with very high agglomerative forces employment is approximately centered with long commute distances and high congestion levels at the other extreme lower agglomerative forces lead to employment that is completely dispersed commute distances of zero and the absence of congestion maximizing output minus congestion never leads to a pattern of land mixing where employment is fully dispersed a market model however often does if the mix at each location is based on the relative magnitude of the land rent offered from residential as opposed to commercial uses

heuristics for sourcing from multiple suppliers with alternative quantity discounts in this paper we analyze the impact of supplier pricing schemes and supplier capacity limitations on the optimal sourcing policy for a single firm we consider the situation where the total quantity to be procured for a single period is known by the firm and communicated to the supplier set in response to this communication each supplier quotes a price and a capacity limit in terms of a maximum quantity that can be supplied to the buyer based on this information the buyer makes a quantity allocation decision among the suppliers and corresponding to this decision is the choice of a subset of suppliers who will receive an order based on industry observations a variety of supplier pricing schemes from the constituent group of suppliers are analyzed including linear discounts incremental units discounts and all units discounts given the complexity of the optimization problem for certain types of pricing schemes heuristic solution methodologies are developed to identify a quantity allocation decision for the firm through an extensive computational comparison we find that these heuristics generate near optimal solutions very quickly data from a major office products retailer is used to illustrate the resulting sourcing strategies given different pricing schemes and capacity limitations of suppliers in this industry we find for the case of capacity constrained suppliers the optimal quantity allocations for two complex pricing schemes linear discount and incremental units discount are such that at most one selected supplier will receive an order quantity that is less than its capacity

agricultural economics beyond the farm gate the industrialization of american agriculture during the past three decades has diminished farm numbers and the farm population while total agricultural production has increased the input finance service processing transportation and distribution industries surrounding production agriculture have now become the dominant economic components of the food and agriculture system the transformation of production agriculture from a major economic sector of the u s economy to minor status has been in progress since the founding days of the republic but has received impetus in the post world war ii era via the technological revolution involving mechanical chemical biological and managerial innovations on the farm what has emerged from this process is a highly interdependent subsystem of the u s economy for providing food and fiber for consumers at home and abroad agricultural scientists including agricultural economists have tended to place undue emphasis upon the technological economic and social aspects of production agriculture as the food and fiber system changed over time while public investments in research and education for the production side of agriculture are admittedly inadequate the lack of attention to the technological and economic problems of the balance of the food and fiber system is deplorable in terms of value added employment or other measures of economic importance the food and fiber system beyond the farm gate is roughly twice that of production agriculture more significantly productivity and inflation problems beyond the farm gate have affected national economic performance more persistently than gyrations in the farm economy per se the overall purpose of this paper is to challenge agricultural economists and policy makers to think about some important issues facing our contemporary economic system this emphasis does not mean that farm production economics is unimportant or unnecessary it is argued however that changes are needed within the agricultural economics profession to deal with a large number of significant economic problems and concerns beyond the farm gate

applied welfare economics with discrete choice models economists have been paying increasing attention to the study of situations in which consumers face a discrete rather than a continuous set of choices such models are potentially very important in evaluating the impact of government programs upon consumer welfare but very little has been said in general regarding the tools of applied welfare economics indiscrete choice situations this paper shows how the conventional methods of applied welfare economics can be modified to handle such cases it focuses on the computation of the excess burden of taxation and the evaluation of quality change the results are applied to stochastic utility models including the popular cases of probit and logit analysis throughout the emphasis is on providing rigorous guidelines for carrying out applied work this abstract was borrowed from another version of this item

knowledge measurement and productivity in a research program we introduce a metric based on bayesian probability theory to evaluate the determinants of scientific discovery and use it to assess an international aquacultural research program consisting of a large number of highly varied projects the metric accommodates not only project variety but a detailed breakdown of the sources of research productivity accounting for example for the contributions of failed as well as successful investigations a mean absolute deviation loss functional form permits decomposition of knowledge gain into an outcome probability shift mean surprise and outcome variance reduction statistical precision allowing productivity to be estimated for each of them separately then combined into a single knowledge production relationship laboratory size is found to moderately boost mean surprise but has no effect on statistical precision while investigator education greatly improves precision but has no effect on mean surprise returns to research scale are decreasing in the size dimension alone but increasing when size and education are taken together suggesting the importance of measuring human capital at both the quantitative and qualitative margins

economic lot size model for price dependent demand under quantity and freight discounts abstract previous studies have developed procedures which determine optimal lot size and selling price when demand depends on price and all unit quantity discounts are offered further recent studies have addressed the concepts of quantity and freight discounts for constant demand in this paper we incorporate quantity and freight discounts in inventory decision making when demand rather than being constant is considered to be dependent upon price an algorithm is developed to determine the optimal lot size and selling price for a class of demand functions including constant price elasticity and linear demand a numerical example is provided to illustrate the model and a computer program is developed to implement the model derived in the paper

an economic order quantity model with a known price increase and partial backordering abstract a constant unit purchase cost is one of the main assumptions in the classic economic order quantity model in practice suppliers sometimes face a known price increase in this paper we develop eoq models with a known price increase and partial backordering under two different assumptions about when the increase will occur we prove the concavity of the extra profit functions for both scenarios if a special order is placed just before the price increases a solution method is proposed and numerical examples are presented

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

the coordinated replenishment dynamic lot sizing problem with quantity discounts abstract in the classical coordinated replenishment dynamic lot sizing problem the primary motivation for coordination is in the presence of the major and minor setup costs in this paper a separate element of coordination made possible by the offer of quantity discounts is considered a mathematical programming formulation for the extended problem under the all units discount price structure and the incremental discount price structure is provided then using variable redefinitions tighter formulations are presented in order to obtain tight lower bounds for reasonable size problems more significantly as the problem is np hard we present an effective polynomial time heuristic procedure for the incremental discount version of the problem that is capable of solving reasonably large size problems computational results for the heuristic procedure are reported in the paper

celebrating a century of the economic order quantity model in honor of ford whitman harris abstract this writing presents a brief introduction to the papers included in the special issue celebrating a century of the economic order quantity model in honor of ford whitman harris published by the international journal of production economics forty one papers covering an extensive scope of inventory management have been incorporated in this volume from contributing authors from 20 countries located in america asia europe and africa this special issue also provides a basis for new directions in inventory management research

resource allocation for agricultural research abstract the allocation of resources for agricultural research is investigated in this paper a theoretical model for optimal allocation of research resources is developed and conditions are derived for an optimal solution the model is applied to existing data for 12 crops and lines of production in israel during the period 1978 1987 the actual allocation and the discrepancy between the actual allocation and the optimal allocation of resources to the crops considered is explained in a regression model by two groups of variables policy variables and political pressure variables the results support the findings of previous studies that political pressure plays a major role in the process of resource allocation for argicultural research

commuting distances in a household location choice model with amenities abstract observed commuting distances generally exceed those predicted by standard models of household location choice this paper develops a model with locational amenities and two job centers it is shown that differences in household preferences for amenities can lead to various types of residential location patterns some of which result in higher average commuting distances in the city

optimal expenditures for agricultural research and extension implications of underfunding significant increases in agricultural productivity will be needed for the united states to meet its future food policy goals related to an abundant and stable food supply the nation s ability to meet this challenge will depend on the level of investment in agricultural research and extension each dollar of underfunding relative to the economically efficient level of research and extension expenditures a will cost the government 2 56 1 50 discounted if it later makes up for the low investment level or b will cost consumers 4 39 3 07 discounted if the government does not make up for the low level of investment

a note on an economic lot size model for price dependent demand under quantity and freight discounts abstract in this study we revisit research contributed by burwell et al 1997 international journal of production economics 48 141 155 where an economic lot size model for price dependent demand under quantity and freight discounts was proposed specifically for the cases of mixed discounts in which the quantity discounts are either of the incremental or all units variety and the freight discounts are of the opposite type we first provide counterexamples to show that adopting the existing algorithm to determine overall optimal lot size and selling price may not achieve the goal of maximizing profit we then propose an easy to understand computational algorithm to obtain an exact solution

funding for agricultural economics needs and strategies for the 1980s public funding for work in agricultural economics teaching research and extension appears to be declining in real terms at the start of the 1980s following two decades of real increases there is a call for reductions in spending by government at all levels a call for less taxes and for public accountability at the same time there are more students in the courses that agricultural economists teach there is a renewed interest in agricultural business curricula graduate study in agricultural economics is attracting new students from the biological and social sciences as well as agriculture the demand for competent applied economists particularly agricultural economists with advanced degrees appears to be growing the anomaly of apparent increases in demand coupled with declining public funding presents a challenge to the profession it should be one for which economists are prepared after all we regularly teach students about economic decision rules for allocating scarce resources among competing ends the political environment requires that we take our classroom lessons seriously and put them in practice in our own operations this paper explores several approaches and strategies for funding work in agricultural economics and more effective use of current resources we begin with an overview of changes in funding during the decade of the 1970s drawing upon secondary data and results of a mail questionnaire sent to agricultural economics department chairmen and administrators in the spring of 1981 we turn then to discussion of the demand current and prospective for services of agricultural economists and the capacity of current institutions to service that demand we conclude with discussion of funding strategies and recommendations on actions which might be pursued by the aaea

modeling quantity discounts under general price sensitive demand functions optimal policies and relationships this paper presents models for determining optimal all unit and incremental quantity discount policies and investigates the effect of quantity discounts on increasing demand and ensuring pareto efficient transactions under general price sensitive demand functions the paper develops optimal quantity discount policies investigates their interrelationships and their benefits to both the supplier and the buyer and gains managerial insights for the scenarios of maximizing the supplier s profit and the joint profit we develop simple and efficient solution approaches for determining the all unit and the incremental optimal decision policies for general price sensitive demand functions we have three main findings first with price sensitive demand there are two incentives in offering quantity discounts increasing demand and ensuring pareto efficient transactions in most cases increasing demand dominates in justifying the offering of quantity discounts second using a single lot size associated with all efficient transactions as with the constant demand case does not hold with the price sensitive demand case third the optimal all unit quantity discount policy is equivalent to the optimal incremental quantity discount policy in benefiting both the supplier and the buyer

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 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

structural change and the recognition of diversity perestroika is not a new reality for north american agriculture structural adjustments in agriculture in rural communities and regions and in economic activities associated with the production and trading of agricultural commodities are made frequently in response to recurrent changes in economic and political conditions increased interdependence of agriculture with other sectors within the national economy and worldwide tutwiler and elliott amplifies the need for understanding the consequences of structural change including the organization and control of the sector macroeconomic and international external sources have also been ac

a comparison of different quantity discount pricing policies in a two echelon channel with stochastic and asymmetric demand information abstract in this paper we study quantity discount pricing policies in a channel of one manufacturer and one retailer the paper assumes that the channel faces a stochastic price sensitive demand but the retailer can privately observe the realization of an uncertain demand parameter the problem is analyzed as a stackelberg game in which the manufacturer declares quantity discount pricing schemes to the retailer and then the retailer follows by selecting the retail price and associated quantity proposed in the paper are four quantity discount pricing policies regular quantity discount fixed percentage discount incremental volume discount and fixed marginal profit rate discount optimal solutions are derived and numerical examples are presented to illustrate the efficiency of each discount policy

on the effectiveness of zero inventory ordering policies for the economic lot sizing model with a class of piecewise linear cost structures we consider an economic lot sizing problem with a special class of piecewise linear ordering costs which we refer to as the class of modified all unit discount cost functions such an ordering cost function represents transportation costs charged by many less than truckload carriers we show that even special cases of the lot sizing problem are np hard and therefore analyze the effectiveness of easily implementable policies in particular we demonstrate that there exists a zero inventory ordering zio policy i e a policy in which an order is placed only when the inventory level drops to zero whose total inventory and ordering cost is no more than 4 3 times the optimal cost furthermore if the ordering cost function does not vary over time then the cost of the best zio policy is no more than 5 6 4 6 times the optimal cost these results hold for any transportation and holding cost functions that satisfy the following properties i they are non decreasing functions and ii the associated cost per unit is non increasing finally we report on a numerical study that shows the effectiveness of zio policies on a set of test problems

taste heterogeneity and urban spatial structure the logit model and monocentric theory reconciled abstract a model of urban spatial structure for a linear and closed monocentric city is formulated by allowing the presence of randomly distributed idiosyncratic tastes for location in an otherwise uniform household population land use equilibrium conditions are shown to have a stochastic representation which depends on the distribution of the idiosyncratic tastes over the population of households a special case in which the multinomial logit model gives the representative household s locational choice probability is derived and examined for a logarithmic utility function it is shown that the stochastic equilibrium can also be obtained as the solution of a welfare optimum problem either by maximizing total social welfare primal or by minimizing total opportunity cost dual either formulation gives the equilibrium allocations and associated decentralizing land prices some comparative statics analysis is undertaken to show that while most results are like those of the alonso mills muth model increasing taste heterogeneity decentralizes the linear urban form flattening the rent and population density gradients the alonso mills muth solution is obtained as an asymptotically limiting case which provides an upper bound on the steepness of the rent and population density gradients and a lower bound on the length of the linear city and the welfare level of the representative consumer

the single item newsboy problem with dual performance measures and quantity discounts abstract this paper considers models for the single item newsboy problem with quantity discount and the following dual performance measure maximize the expected profit subject to a constraint that the probability of achieving a target profit level is no less than a predetermined risk level we also consider two types of quantity discount all unit and incremental for our models with zero shortage cost a closed form solution for determining the optimal order quantity is derived however models with positive shortage cost can only be solved numerically

optimal policy for an inventory system with backlogging and all units discounts application to the composite lot size model this paper examines an inventory model with full backlogging and all units quantity discounts the practical scenario of a salesperson offering compensation to a client so as not to lose the sale is considered the cost of a backorder thus includes both a fixed cost and a further cost which is proportional to the length of time the said backorder exists a first algorithm is developed to determine the optimal policy while some extensions to this algorithm are obtained that include additional conditions on the model in particular the well known composite lot size model developed by tersine is solved incorporating a new stockout cost and a new all units discount numerical examples are provided to illustrate the application of the algorithms

incorporating quantity discounts to the eoq model with transportation costs abstract this article extends a previous economic order quantity eoq model with two modes of transportation namely truckload tl and less than truckload ltl carriers by introducing all units and incremental quantity discount structures into the analysis exact algorithms are developed for each quantity discount structure to compute optimal policies for single stage models over an infinite planning horizon

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

invariance of expected utilities in logit models abstract an unnoticed and restrictive property of the logit model is proved the expected utility or expected utility change conditional on having selected an alternative i is invariant over all alternatives in the choice set this limits the use of logit in situations where expected utilities should realisticly vary by choice made the probit model is not subject to this restriction

variety and size regulation in discrete choice oligopoly imperfectly competitive markets for a differentiated product may underprovide brand variety when consumer tastes for brands are highly heterogeneous we show that when the brands in question are indivisible in consumption and each consumer buys a customized quantity or size of the preferred brand only a welfare improvement can be obtained by regulating the size of purchase we study neutral size regulation which requires that the size of purchase be set equal to the size that would prevail in the absence of regulation this improves brand variety and consumer surplus provided consumer tastes are sufficiently heterogeneous

an economic order quantity model with partial backordering and a special sale price abstract a constant unit purchase cost is one of the main assumptions in the classic economic order quantity model in practice suppliers sometimes offer special sale prices to stimulate sales or decrease inventories of certain items in this paper we develop an eoq model with a special sale price and partial backordering we prove the convexity of the cost reduction function if a special order is placed at the special sale price a solution method is proposed and numerical examples are presented

incorporating quantity discounts and their inventory impacts into the centralized purchasing decision multi site organizations must balance conflicting forces to determine the appropriate degree of purchasing centralization for their respective supplies the ability to garner quantity discounts represents one of the primary reasons that organizations centralize procurement this paper provides methodologies to calculate optimal order quantities and compute total purchasing and inventory costs when products have quantity discount pricing procedures for both all units and incremental quantity discount schedules are provided for four different strategic purchasing configurations scenarios complete decentralization centralized pricing with decentralized purchasing centralized purchasing with local distribution and centralized purchasing and warehousing for ordering decisions under local distribution procedures to determine optimal order quantities and costs are presented in a precise form that could be easily implemented into spreadsheets by practicing managers for the more complicated multi echelon scenarios we introduce a single cycle policy with a tailored aggregation refinement step that performs very well under experimentation when compared to a conservative bound