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

public sector efficiency evidence for new eu member states and emerging markets in this article we analyse public sector efficiency in the new member states of the eu compared to that in emerging markets after a conceptual discussion of expenditure efficiency measurement we compute efficiency scores and rankings by applying a range of measurement techniques the study finds that expenditure efficiency across new eu member states is rather diverse especially as compared to the group of top performing emerging markets in asia econometric analysis shows that higher income civil service competence and education levels as well as the security of property rights seem to facilitate the prevention of inefficiencies in the public sector

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

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

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

explaining differences in public sector efficiency evidence from russia s regions summary using the case of russia s regions this paper extends the literature on public sector efficiency in three directions an attempt to better understand differences in public sector efficiency through the study of subnational governments in one country the first examination of public sector efficiency of subnational governments in emerging markets and the first study of public sector efficiency in russia three types of scores of public sector performance and efficiency indicate substantial differences across regions an econometric examination suggests that they are largely explained by per capita income the share of federal transfers in subnational government revenue quality of governance and democratic control and the level of spending

the dual nature of public goods and congestion the role of fiscal policy revisited the role of fiscal policy is examined when public goods provide both productive and utility services in the presence of congestion the consumption tax is shown to be distortionary optimal fiscal policy involves using consumption based instruments in conjunction with the income tax an income tax financed increase in government spending dominates both lump sum and consumption tax financing replacing the lump sum tax with an income tax to finance a given level of spending dominates introducing an equivalent consumption tax these results contrast sharply with the literature where the consumption tax is generally viewed as the least distortionary source of public finance on re examine le role de la politique fiscale quand les biens publics fournissent a la fois des services productifs et de bien etre quand il y a congestion on montre que la taxe sur la consommation cree des distorsions la politique fiscale optimale consiste a faire bon usage des taxes sur la consommation en conjonction avec l impot sur le revenu une depense gouvernementale financee par l impot sur le revenu est preferable a un financement par un paiement forfaitaire ou une taxe sur la consommation remplacer le paiement forfaitaire par un impot sur le revenu pour financer un niveau donne de depense vaut mieux qu introduire une taxe equivalente sur la consommation ces resultats contrastent vivement avec ce qu on trouve dans la litterature specialisee ou l on considere generalement la taxe sur la consommation comme la source de finance publique qui cree le moins de distorsion

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

an order level lot size inventory model with inventory level dependent demand and deterioration abstract many inventory models have been developed for various deteriorating items with constant demand rate it is a common experience that for perishable consumer goods the age of inventory has a negative impact on the demand due to the loss of consumer confidence on such product consumers tend to keep off perishable items which have reached closer to their expiry dates this paper describes an inventory model in which the demand is considered as a composite function consisting of a constant component and a variable component which is proportional to the inventory level in the periods when there is a positive inventory buildup the rate of production is considered finite and the decay rate as exponential the total cost function is composed of four cost components of all phases of the cycle backorder replenishment inventory buildup inventory depletion and shortage this cost function is later reduced to a two variable function using boundary relations to determine iteratively the set of values of the variables that resulted in minimum cost per cycle the optimum lot size and order level were then obtained with relations established previously results are demonstrated for an instance of the model

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

simulation study of the price differentiation effect in a stochastic deteriorating inventory with heterogeneous consumers freshness sensitivity a fixed price policy regardless of expiration date may result in unsold inventory and sales loss price reduction over time as the expiration date approaches motivates customers to purchase all items including the ones that are left with only a short interval until their expiration we conduct a discrete event simulation that captures the main characteristics of this phenomenon results show that a moderate differentiation of price increases profits by 6 a larger differentiation reduces profits profits are the highest for freshness oriented customers a fixed price policy is preferred in an environment of large variance and expected near term expirations

the chinese box the opaque economic borders of the chinese state although the state in china is no longer all encompassing as it had been during the pre 1979 centrally planned period it still reaches into numerous areas of the economy notably through its continuing ownership of state owned enterprises as a result china poses a paradox in that it has incomplete property rights and rule of law which are thought to be essential for growth there are though numerous inefficiencies associated with such a gradual transition which may have maintained a stable growth rate in the past but could hamper future economic development as a key example state owned firms continue to benefit from financial repression in which they received preferable allocations of credit thus china s high savings rate fuels investment which has driven growth but is increasingly inefficient as credit is funnelled to the less productive soes this inefficiency points to the need for legal and institutional reforms which may conflict with the still broad but opaque borders of the chinese state copyright 2011 oxford university press

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

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

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

estimates of the black economy based on consumer demand approaches we propose a consumer demand system approach to estimating the size of the black economy where alternative hypotheses affecting the empirical results can be tested in a nested framework this approach allows for the estimation of the under reporting of household income from various sources dispensing with the need to use arbitrary criteria to classify households by their main source of income it also avoids potential bias in black economy estimates arising from mistaking preference heterogeneity substitution as income effects we illustrate these arguments by estimating the extent to which self employment income in the uk is underreported using parametric and nonparametric techniques the black economy broadly defined as the economic activities that are hidden from public authorities to avoid taxation has recently received increased attention in the literature due to arguments that the rising tax burden and state regulation is driving economic activity underground tanzi and schuknecht 1997 enste and schneider 1998 the usefulness of attempts to estimate the size of the black economy however is a controversial issue the sceptics emphasise the difficulties associated with the precise definition of black economy activities and point to the widely different estimates of the size of these activities resulting from alternative methods dixon 1999 tanzi 1999 thomas 1999 authors approaching the subject in an optimistic frame of mind emphasise positive aspects of estimating the size of the black economy such as the correct measurement of gdp and other macroeconomic variables e g employment and the design of policy and econometric models bhattacharyya 1999 giles 1999 the controversy on estimation issues however does not subtract from the widespread concern about the undesired consequences of the black economy undeclared economic activities reduce the tax base thereby undermining the financing of public goods and social protection a country trying to curtail the loss of tax revenue by raising tax rates can create a vicious cycle as this reinforces the incentive not to declare economic activities to the public authorities high tax rates have a distorting effect resulting in inefficient allocation of resources due to unequal opportunities and willingness to evade in different sectors of the economy and can undermine the ability of the country to compete internationally distortions in the labour market can also arise because individuals working in the black economy may have difficulty in moving from one job to another furthermore in countries where health pension and other social security payments are not universal individuals working in the black economy and their families are outside the

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

the application of queueing theory to continuous perishable inventory systems this paper develops two distinct models for studying inventory systems with continuous production and perishable items the perishable items have a deterministic usable life after which they must be outdated for each of the models analytical expressions derived from queueing theory are found for the steady state distribution of system inventory knowledge of this steady state behavior may be used for evaluation of system performance and for consideration of alternatives for improving system performance both models assume that inventory is replenished by a continuous production process the first model assuming continuous inventory units has poisson demand requests with the size of each request distributed as an exponential random variable the second model has poisson demand requests with all demands being for a single unit the analysis for both models exploits the similarity of the inventory system with a single server queueing system

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

uses and abuses of estimates of the underground economy ered valuable by at least a part of society narcotics production and distribution prostitution gambling these activities can be large in some countries and should be counted in the national accounts of all countries although they rarely are their omission affects the comparability of data across countries the incomes generated by illegal activities are rarely taxed many other activities such as those associated with the subsistence or informal sectors are estimated rather than measured and are generally not taxed because of the low value they generate to those who engage in them in conclusion there are many reasons beside the ones discussed in this paper why the measurements of national output may not be complete about two decades ago a few economists became convinced that many normal economic activities that should be measured and taxed were taking place underground or in the shadow thus presumably escaping the attention of the statistical offices of the tax authorities and more generally of the government regulators some of these economists also claimed that like alice in wonderland these hidden activities were growing in a ridiculous fashion see gutmann 1977 and feige 1979 by the late 1970s the role of government had grown enormously so that the level of taxation and the tax rates had risen sharply and regulations had proliferated in many countries see tanzi and schuknecht 1997 these developments had created strong incentives for individuals and enterprises to go underground to avoid taxes and regulatory restrictions thus a good case could be made that what came to be called the underground economy was a phenomenon to worry about newspaper articles were ready to accept the

comparative politics and public finance we propose a model with micropolitical foundations to contrast different political regimes compared to a parliamentary regime the institutions of a presidential congressional regime produce fewer incentives for legislative cohesion but more separation of powers these differences are reflected in the size and composition of government spending a parliamentary regime has redistribution toward a majority less underprovision of public goods and more rents to politicians a presidential congressional regime has redistribution toward powerful minorities more underprovision of public goods but less rents to politicians the size of government is smaller under a presidential regime this last prediction is consistent with cross country data

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

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

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

multicointegration and sustainability of fiscal practices i introduction governments are charged with the responsibility of crafting national budgets over time budgets tend to move between balance surplus and deficit these fluctuations result from the fact that all too often a government makes financial decisions in one year that have implications for spending commitments and revenue streams a number of years down the road thus responsible government budgeting involves examining the budget position over time that is engaging in intertemporal budgeting economists generally utilize two criteria to assess the intertemporal budget s sustainablity does the government run persistent deficits if so what is the resulting level of debt are these two criteria sufficient to make predictions regarding budget sustainability recent work by bohn 1995 1998 and ball et al 1998 suggests that budgets are far too complicated to be evaluated with respect to deficits and debt alone these authors have shown that persistent deficits and accumulation of debt does not necessarily imply that the debt is unmanageable and hence fiscal processes unsustainable the implication of their work is that the standard approach to testing whether government adheres to its intertemporal budget constraint cointegration analysis does not provide sufficient criteria for determining whether the fiscal process is truly sustainable consequently in this article we develop a more encompassing set of criteria under more realistic assumptions for determining whether a country exhibits a sustainable budgeting process our criteria for sustainability are based the multicointegration approach first presented by granger and lee 1989 1990 and further developed in engsted gonzalo and haldrup 1997 and haldrup 1998 the budgeting practices of 15 industrialized countries belgium canada denmark finland france great britain greece italy the netherlands norway portugal spain sweden switzerland and the united states are evaluated in terms of the criteria our sample spans the modern era 1960 98 we extend the intertemporal budgeting literature by employing the multicointegration framework to develop the appropriate policy responses to deficits and debt accumulation and to test for their presence the methodology assesses both the stock and flow relationships that should characterize sustainable fiscal processes when the data are nonstationary cointegration between the spending revenue flow relationship is the first component of our criteria cointegration between the flow of revenue spending and the stock of debt is the second jointly these conditions characterize multicointegration between government spending and revenue in the multicointegration case the system is characterized by a complex stock flow equilibrium relationship that is not uncommon in intertemporal models of economic behavior such a relationship is typically associated with issues of optimal control where the levels and rates of change of the variables making up the system are determinants of the policy response multicointegration can ensure that a country s budgeting strategy is sustainable in bad states of nature that is when the rate of economic growth falls short of the real interest rate on sovereign debt 1 bohn 1995 and ball et al 1998 point out that existing theoretical models that underpin traditional sustainability tests are too simple specifically bohn 1995 shows that the sustainability of imbalances in a stochastic setting involves satisfying an intertemporal budget constraint and a transversality condition that differs from that implicit in simple deterministic models the transversality condition requires that the limit of the debt discounted at a rate that is a function of the probability distribution of future debt and the marginal rate of substitution between present and future consumption be zero this correct discounting is critical in economies where the rate of growth has been higher than the real interest rate

budgetary devices for curbing spending prone ministers and bureaucrats in this paper i study asimple game of the budgetary process thegame has three players a spending proneminister who proposes a budget a primeminister who accepts or vetoes and abureaucrat who provides non verifiableinformation about policy the bureaucratis appointed by the spending minister ishow that in this setting public spendingis excessive this result stems from theproposal power of the minister and hisincentive to appoint a spending pronebureaucrat next i examine two devices forcontrolling public spending binding budgettargets imposed by the prime minister anddelegating veto power to a spending aversefinance minister it is shown that thelatter device is more effective than theformer device to curb a spending proneminister because it not only reduces theproposal power of the spending minister but also induces him to appoint lessspending prone bureaucrats

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

logrolling in the u s congress i introduction a long standing question in political science is whether exchange occurs in legislatures as it is expected in any economy where the intensity of demand varies the issue was originally raised by buchanan and tullock 1962 and expanded by coleman 1966 and mueller 1967 the subsequent literature has produced numerous models of vote trading haefele 1971 riker and brams 1973 koford 1982a much of the work suggests that vote trading leads to chaotic results see for example riker and brams 1973 kramer 1977 and mckelvey 1976 currently vote trading s quantitative importance and optimality are unknown references to logrolling go back to the early literature in political science bentley 1907 refers to it and since then scholars such as mayhew 1966 and ferejohn 1974 have provided primarily anecdotal evidence for logrolling the economic analysis of logrolling has mostly been theoretical and little work has been done to assess the qualitative and quantitative importance of vote trading in legislatures however much might be learned from such analysis given the apparent puzzle that for most roll calls votes on parts of bills only a minority of districts stand to gain yet such proposals get passed until recently vote trading has not been identified empirically stratmann 1992 is the only paper that identifies vote trades statistically and it looks only at vote trades among agricultural interests however it would be interesting to know whether logrolling is prevalent in circumstances other than farm commodity programs we need to identify logrolling coalitions to assess how widespread logrolling agreements are we expect them to be common if the intensity of demand for legislation varies related to the issue of vote trading is the question of what factors determine congressional voting behavior major elements in a legislator s voting decision are constituency interests ideology party and perhaps vote trading one segment of the literature on congressional voting has focused on the role of political parties as an important force determining a legislator s voting decision some authors have argued that parties provide an organizational framework within which logrolling will happen see for example fiorina 1974 koford 1987 weingast and marshall 1988 johnson and stratmann 1992 alternatively lindsay and maloney 1988 suggest that party discipline forces a legislator to vote for or against a piece of legislation the latter view implies that on some issues party affiliation forces the legislator to vote against constituency interests 1 whether party affiliation is a signal to constituencies of one s overall propensity to vote on bills or a means to build coalitions or whether both elements are important is an unresolved question voting along party lines can be due to party loyalty or party pressure promoting the interests of one s constituency or logrolling within the party to answer questions about voting along party lines and about vote trading and coalitions within a quantitative framework one has to distinguish empirically between party loyalty and logrolling coalitions that are organized within a party empirical studies have typically included a party dummy variable in regression equations however if logrolling coalitions are organized within a party such a dummy variable will measure both potential party loyalty or potential party discipline and membership in a logrolling coalition this paper uses a different approach to separate the logrolling variable from the party loyalty variable and so distinguishes between voting for a proposal because of membership in a log rolling coalition organized by a party and because of potential party discipline this paper analyzes a broad range of votes where logrolling has been reported the analysis spans two congresses 1959 to 1962 and examines trades between interests favoring subsidies for city interests labor interests and farm interests

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

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

an optimal procurement policy for items with an inventory level dependent demand rate and fixed lifetime abstract this paper investigates an optimal procurement policy for items with an inventory level dependent demand rate and fixed lifetime the demand rate is assumed to be a function of current inventory level and each unit has its fixed expiry date so any units which remain unused by their expiry date are considered outdated and must be disposed of for the system presented a mathematical model and solution methodology were developed sensitivity of the decision variables to changes in the parameter values is examined and future research needs are discussed in brief

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

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

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

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

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

privatization financial development property rights and growth abstract this study analyzes how prevailing institutional arrangements i e property rights contracting rights political institutions and corporate governance practices affect privatized firms performance capital markets development and economic growth most of the studies surveyed show that privatization enhances privatized firms performance efficiency and profitability which percolates to economic growth privatized firms performed better in countries with better regulatory and legal frameworks partial privatization may be beneficial in countries with weak institutions namely the french civil law countries the stronger the economic and the governing institutions the easier it is for privatized firms to thrive and contribute to economic growth overall privatization allows firms to achieve improved efficiency while driving the development of the financial sector

the size and development of the shadow economy an empirical investigation from states of india abstract using the state level data from india this paper investigates the size of the hidden economy in indian states over the period 1974 75 to 1995 96 our analysis has shown that after liberalization of the indian economy in 1991 92 the growth in the size of the hidden economy has decreased on an average our results show that the growth in the size of the hidden economy is approximately 4 less in scheduled election years than in all other years we also demonstrate that the growth is significantly lower in those states where the coalition government is in power an increased growth of newspapers and the literacy rates translate to cleaner governance e g to fewer amounts of shadow economy activities in the economy

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