the impacts of urban pricing on social and spatial inequalities the case study of lyon france with the aim of making a city sustainable this paper evaluates the impact of setting up urban toll on inequalities we use several indicators gini theil and atkinson indices to measure changes in the concentration of incomes and gravity based accessibility in the case of the lyon metropolitan area france we simulate a cordon pricing and evaluate its impacts on inequalities we adopt a comparison based approach to reduce the bias resulting from the spatial division in agreement with the literature we show that different inequality indicators produce contrasted and sometimes contradictory results both at the scale of zones or metropolitan level results from theil and atkinson indicators point out introducing a toll can reduce inequalities in the most peripheral zones although we observe an accessibility improvement particularly for central zones the first ring adjacent to the toll zone is the most adversely affected by toll

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

are estimates of earnings inequality sensitive to measurement choices a case study of canada in the 1980s while it is necessary that researchers make choices in order to estimate inequality the reasons for the measurement choices and their impact on inequality estimates have not been widely assessed this paper uses canadian data from the 1980s to analyse whether inequality estimates are sensitive to common measurement choices seemingly minor technical choices about the treatment of outlying observations such as the use of top income coded data exclusion of very high and low observations and differences among data sets in the capture of very high observations affect estimates of inequality further the impact of the treatment of outlying observations on inequality estimates are at least as large as the impact of measurement choices of a conceptual nature such as the income definition and population selection the sensitivity of inequality estimates to measurement choices which often remain invisible affect inferences about the relative degree of inequality at a given point in time among countries and

changing income inequalities within and between nations new evidence fresh data sources on cross national income are examined to document recent changes in the composition of world income inequality within and between nations new evidence shows that during the 1980s and 1990s the composition of world income inequality experienced a fundamental change characterized by the diminishing significance of between nation income differences and the growing prominence of within nation inequalities two competing trends account for this change 1 steady growth in the average level of income inequality within nations and 2 a decline in income inequality between nations these recent trends signify a reversal in one of the major legacies of the industrial revolution the internationalization of world income inequality across national borders the findings raise important questions for future studies of cross national inequality and development

risk perceptions and distributional judgments abstract we examine the role of laboratory questionnaire experiments and recent applied empirical research on attitudes in understanding the relationships between people s perceptions of inequality and their perceptions of risk we consider risk in three interpretations in vacuo in day to day life and in the original position

computing the non stationary replenishment cycle inventory policy under stochastic supplier lead times in this paper we address the general multi period production inventory problem with non stationary stochastic demand and supplier lead time under service level constraints a replenishment cycle policy r n s n is modeled where r n is the n th replenishment cycle length and s n is the respective order up to level we propose a stochastic constraint programming approach for computing the optimal policy parameters in order to do so a dedicated global chance constraint and the respective filtering algorithm that enforce the required service level are presented our numerical examples show that a stochastic supplier lead time significantly affects the structure of the optimal policy with respect to the case in which the lead time is assumed to be deterministic or absent

an milp approximation for ordering perishable products with non stationary demand and service level constraints abstract we study the practical production planning problem of a food producer facing a non stationary erratic demand for a perishable product with a fixed life time in meeting the uncertain demand the food producer uses a fifo issuing policy the food producer aims at meeting a certain service level at lowest cost every production run a setup cost is incurred moreover the producer has to deal with unit production cost unit holding cost and unit cost of waste the production plan for a finite time horizon specifies in which periods to produce and how much we formulate this single item single echelon production planning problem as a stochastic programming model with a chance constraint we show that an approximate solution can be provided by an milp model the generated plan simultaneously specifies the periods to produce and the corresponding order up to levels the order up to level for each period is corrected for the expected waste by explicitly considering for every period the expected age distribution of the products in stock the model assumes zero lead time and backlogging of shortages the viability of the approach is illustrated by numerical experiments simulation shows that in 96 4 of the periods the service level requirements are met with an error tolerance of 1

age based vs stock level control policies for a perishable inventory system abstract in this study we investigate the impact of modified lotsize reorder control policy for perishables which bases replenishment decisions on both the inventory level and the remaining lifetimes of items in stock we derive the expressions for the key operating characteristics of a lost sales perishable inventory model operating under the proposed age based policy and examine the sensitivity of the optimal policy parameters with respect to various system parameters we compare the performance of the suggested policy to that of the classical q r type policy through a numerical study over a wide range of system parameters our findings indicate that the age based policy is superior to the stock level policy for slow moving perishable inventory systems with high service levels

ethnic inequality and poverty in malaysia since may 1969 part 1 inequality abstract the race riots that broke out in kuala lumpur in may 1969 triggered a national public effort to greatly reduce both malaysia s longstanding ethnic inequalities and its high incidence of poverty this paper studies how various measures of ethnic inequality evolved since 1969 two conceptual distinctions are emphasized that between income inequality and polarization on the one hand and that between relative and absolute inequality on the other over the last 50 years the poorest ethnic group the bumiputera have had the highest growth rate of household incomes which helped assure a substantial long term decline in relative between group inequality which in turn substantially reduced overall income inequality measures of ethnic polarization moved highly synchronously with between group inequality the differential growth rates by ethnicity were not enough to prevent rising absolute inequality given the extent of the initial ethnic disparities despite the progress against relative inequality malaysia s absolute disparities by ethnicity are now even larger than 50 years ago the second paper of this two part paper examines the contribution of lower relative ethnic inequality to the country s progress against poverty

dalton improving indirect tax reform a tax reform is dalton improving if it improves social welfare for all possible social welfare functions that conform to hugh dalton s principle of transfers according to this principle there exists a prior social ranking of households and a transfer is approved if it it distributes from high ranking rich to low ranking poor households without altering the ranking itself in this paper the authors develop a procedure for identifying marginal dalton improving reforms in the context of indirect taxation the methodology is illustrated using data on excise taxes in the united kingdom copyright 1995 by american economic association

a simple approach for assessing the cost of system nervousness abstract a well known problem in coordinating supply chain inventories is that replenishment decisions are revised due to stochastic demands this issue is often referred to as system nervousness the literature distinguishes between two types of nervousness setup oriented and quantity oriented it is widely accepted that cost of nervousness is difficult to measure we argue that this cost can be evaluated by means of three well established inventory control strategies static uncertainty dynamic uncertainty and static dynamic uncertainty these strategies reflect extreme cases with regard to the setup and the quantity oriented nervousness and provide a simple yet an objective measure to assess the cost of system nervousness our results are of practical importance we highlight that the setup oriented nervousness which is considered to be the most critical in practice can be eliminated with a minor cost penalty this is however not the case for the quantity oriented nervousness

the estimation of welfare levels of a cardinal utility function in order to measure an individual s welfare function of income wfi van praag 1968 1971 the individual is confronted with various welfare levels and asked to associate income levels with them the welfare levels are given as verbal qualifications like good sufficient bad etc it is assumed that these verbal qualifications correspond to intervals of equal length of the range of the wfi here we want to test this assumption a first principal component model is applied the intervals of the range of the wfi associated with the verbal qualifications are estimated and a test of their equality is performed

dynamic uncapacitated lot sizing with random demand under a fillrate constraint abstract this paper deals with the single item dynamic uncapacitated lot sizing problem with random demand we propose a model based on the static uncertainty strategy of bookbinder and tan 1988 in contrast to these authors we use exact expressions for the inventory costs and we apply a fillrate constraint we present an exact solution method and modify several well known dynamic lot sizing heuristics such that they can be applied for the case of dynamic stochastic demands a numerical experiment shows that there are significant differences in the performance of the heuristics whereat the ranking of the heuristics is different from that reported for the case of deterministic demand

rethinking inequality decomposition with evidence from rural china we examine inequality decompositions by income source and describe a general regression based approach for decomposing inequality the approach provides an efficient and flexible way to quantify the roles of variables like education and age in a multivariate context we illustrate the method using survey data from china the empirical results demonstrate how sharply different conclusions can emerge for different decomposition rules we explain how these differences reflect the treatment of equally distributed sources of income and we discuss implications for how results from inequality decomposition are interpreted a renewed interest in economic growth political economy and the distribution of income has again placed the economics of income inequality firmly on the academic research agenda relatively poor performances in latin america have been contrasted with success stories in east asia and recent evidence on the changing income distributions of emerging economic giants like china has

augmenting the lot sizing order quantity when demand is probabilistic abstract in this paper we consider a single item discrete time lot sizing situation where demand is random and its parameters e g mean and standard deviation can change with time for the appealing criterion of minimizing expected total relevant costs per unit time until the moment of the next replenishment we develop two heuristic ways of selecting an appropriate augmentation quantity beyond the expected total demand through to the planned deterministic time of the next replenishment the results of a set of numerical experiments show that augmentation is important particularly when orders occur frequently i e the fixed cost of a replenishment is low relative to the costs of carrying one period of demand in stock and the coefficient of variability of demand is relatively low but also under other specified circumstances the heuristic procedures are also shown to perform very favourably against a hindsight baseline s s policy especially for larger levels of non stationarity

modelling imperfect advance demand information and analysis of optimal inventory policies we consider an inventory control problem where it is possible to collect some imperfect information on future demand we refer to such information as imperfect advance demand information adi which may occur in different forms of applications a simple example is a company that uses sales representatives to market its products in which case the collection of sales representatives information as to the number of customers interested in a product can generate an indication about the future sales of that product hence it constitutes imperfect adi other applications include internet retailing vendor managed inventory vmi applications and collaborative planning forecasting and replenishment cpfr environments we develop a model that incorporates imperfect adi with ordering decisions under our system settings we show that the optimal policy is of order up to type where the order level is a function of imperfect adi we also provide some characterizations of the optimal solution we develop an expression for the expected cost benefits of imperfect adi for the myopic problem our analytical and empirical findings reveal the conditions under which imperfect adi is more valuable

non stationary stochastic inventory lot sizing with emission and service level constraints in a carbon cap and trade system firms worldwide are taking major initiatives to reduce the carbon footprint of their supply chains in response to the growing governmental and consumer pressures in real life these supply chains face stochastic and non stationary demand but most of the studies on inventory lot sizing problem with emission concerns consider deterministic demand in this paper we study the inventory lot sizing problem under non stationary stochastic demand condition with emission and cycle service level constraints considering carbon cap and trade regulatory mechanism using a mixed integer linear programming model this paper aims to investigate the effects of emission parameters product and system related features on the supply chain performance through extensive computational experiments to cover general type business settings and not a specific scenario results show that cycle service level and demand coefficient of variation have significant impacts on total cost and emission irrespective of level of demand variability while the impact of product s demand pattern is significant only at lower level of demand variability finally results also show that increasing value of carbon price reduces total cost total emission and total inventory and the scope of emission reduction by increasing carbon price is greater at higher levels of cycle service level and demand coefficient of variation the analysis of results helps supply chain managers to take right decision in different demand and service level situations

customer order information leadtimes and inventories we have an inventory to manage the scenario is standard in all respects save one instead of arriving unannounced customers provide advance warning of their demands how should we use this information and what is its effect on system performance the answers turn out to be strikingly simple there are very simple policies which perform effectively in some cases optimally also such demand leadtimes improve performance in precisely the same way that replenishment leadtimes degrade it

a new class of stock level dependent ordering policies for perishables with a short maximum shelf life many perishables such as fresh food and blood platelet concentrates are characterized by a short maximum shelf life as demand is often highly uncertain the outdating and shortages figures can be very high especially when frequent replenishment is not possible or inefficient due to fixed ordering cost we present a new class of stock level dependent ordering policies the s s q q policy which is a periodic review s s policy with the order quantity restricted by a minimum q and maximum q optimal weekday dependent parameter values are derived by dynamic programming and simulation the s s q q policy performs nearly optimal and improves the s s policies in many cases by 4 25

ethically flexible measures of poverty this paper introduces new measures of both relative and absolute poverty using the notion of representative income of a community corresponding to the censored income distribution these new measures satisfy the monotonicity and transfer axioms proposed by sen 1976 in all cases

biased perceptions of income distribution and preferences for redistribution evidence from a survey experiment abstract individual perceptions of income distribution play a vital role in political economy and public finance models yet there is little evidence regarding their origins or accuracy this study examines how individuals form these perceptions and explores their potential impact on preferences for redistribution a tailored household survey provides original evidence on systematic biases in individuals evaluations of their own relative position in the income distribution the study discusses one of the mechanisms that may generate such biases based on the extrapolation of information from endogenous reference groups and presents some suggestive evidence that this mechanism has significant explanatory power the impact of these biased perceptions on attitudes toward redistributive policies is studied by means of an experimental design that was incorporated into the survey which provided consistent information on the own ranking within the income distribution to a randomly selected group of respondents the evidence suggests that those who had overestimated their relative position and thought that they were relatively richer than they were tend to demand higher levels of redistribution when informed of their true ranking

inventory control with limited capacity and advance demand information manufacturers make production decisions and carry inventory to satisfy uncertain demand when holding and shortage costs are high carrying inventory could be even more expensive for acapacitated production system recent developments in information technology and sales strategies enabled firms to acquire collect or induce advance demand information we address a periodic review stochastic capacitated finite and infinite horizon production system faced by a manufacturer who has the ability to obtain advance demand information we establish optimal policies and characterize their behavior with respect to capacity fixed costs advance demand information and the planning horizon with a numerical study we quantify the value of advance demand information and additional capacity for specific problem instances we illustrate how advance demand information can be a substitute for capacity and inventory

inequality aversion versus risk aversion inequality aversion and risk aversion are widely assumed in economic models however existing economic literature fails to distinguish between the two this paper presents methodology and a laboratory experiment which separates inequality aversion from risk aversion in a set of laboratory experiments subjects had to choose between two risky alternatives which pay meaningful prizes with the same individual risk but different levels of egalitarianism thus the choice of the more egalitarian alternative implies a higher level of inequality aversion the experiment was conducted among children some of whom live on a communal system kibbutz and some in the city

reducing inequalities toward the development of a market for income inequality abstract the objective of this study is to propose the development of a market for income inequality by specifying a firm s contribution to income inequality and outlining a simple model to find the equilibrium price for a given target of income inequality reduction the paper reviews the concepts of firm heterogeneity and externalities in relation to income inequality it then proposes a model by establishing income inequality reduction targets for a population of firms presenting a marginal income inequality reduction cost curve and matching demand and supply to derive the equilibrium price and ends by simulating a market for income inequality reduction using data from a sample of fifteen firms this paper shifts the focus of income inequality research and policy to the firm and proposes a market based mechanism for firms to reduce income inequality

blood platelet production with breaks optimization by sdp and simulation abstract the production and inventory management of blood products at blood banks and hospitals is a problem of general human interest as a shortage may put lives at risk shortages are to be kept to a minimum as the supply is voluntary and costly any spill of unused blood products is also to be minimized blood platelets thrombocytes which are the most expensive and perishable blood product have the complication of a limited shelf life of only 5 7 days a general figure in the western world the usa and western europe for the spill of blood platelets is in the order of 15 20 a combined new approach is therefore presented which combines stochastic dynamic programming sdp and simulation to provide i practical simple order up to rules that are nearly optimal ii formal theoretical support the approach has been applied to a dutch regional blood bank numerical results show a significant reduction of the figures from 1 to 1 for shortages 20 to 1 for spill a practical question for blood bank managers that still remains is how to anticipate irregular production breaks like at easter and christmas the present paper therefore will extend the combined sdp simulation approach to include such breaks the main findings are also for these breaks a simple order up to rule remains to be nearly optimal also for these breaks the outdating and shortages can be kept less than 1 the stationary periods with production and the non stationary breaks without can be integrated the approach thus seems suitable for practical implementation

how polarized is the global income distribution abstract the interest in the level of global inequality has surged in recent years this paper complements existing estimates of global inequality by providing the first estimates of the level of bipolarization of the global income distribution during 1975 2010 global bipolarization declined substantially according to relative measures while it increased according to absolute measures the results mirror trends in global inequality over the same period

inverse productivity land quality labor markets and measurement error abstract this paper examines the role that land quality and imperfect markets play in generating the inverse productivity relationship in the international crop research institute for the semi arid tropics icrisat data differences in land quality largely explain the inverse productivity ip relationship in the random effects profit regression but not in labor demand regressions controlling for labor and land market failures and differences in soil quality eliminates the ip relationship for male labor but not female labor in the random effects estimates the inverse relationship is much stronger in fixed effects than random effects estimates suggesting that the farm size variable may be subject to measurement error a view supported by the results of instrumental variables estimation

consistent income tax structures when households are heterogeneous the paper examines the redistributive impact of income taxation for heterogeneous populations an equivalent income function is introduced in order to adjust the incomes of different types of households and the redistributive performance of the tax system is evaluated by comparing the lorenz curves of the distributions of before and after tax equivalent incomes inequality reduction after tax imposes mild consistency conditions which are met by most current tax systems if the inequality reducing effect of taxation is required to be independent of the reference household type then the structure of the equivalent income function is fully determined by the inequality concept journal of economic literature classification numbers d31 d63 h24

approximate solutions for a stochastic lot sizing problem with partial customer order information we address a stochastic single product manufacturing system in a make to stock environment with partial knowledge on future demand resulting from customers ordering in advance of their actual needs the problem consists of determining the optimal size of a production lot to replenish inventory so that delivery promises are met on time at the expense of minimal average costs a markov decision model is formulated for finding the optimal policy however since the optimal policy is likely to be too complex in most practical situations we present approximate strategies for obtaining good production lot sizes the well known r s inventory policy is compared to two rules where production decisions take into account the available information on future customer requirements and the probabilistic characterization of orders yet to be placed furthermore it is shown that the s s inventory policy is a special case of one of the rules an extensive numerical study reveals that the newly developed strategies outperform classical inventory policies

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

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

multiple items procurement under stochastic nonstationary demands abstract in the consumer goods wholesaling and retailing industry a large number of stock keeping units must be managed on a regular basis the items are typically purchased in families each family being associated with a specific external vendor and usually there are some constraints on family order quantities and there are frequent opportunities to buy at a temporary low price the demand for an item is often stochastic and not stationary in this paper by computing procurement plans over rolling planning horizons we transform this difficult sequential decision problem into a multi period static decision problem under risk the problem is initially formulated as a stochastic program with simple recourse and a branch and bound algorithm is designed to solve an equivalent deterministic program a piecewise concave approximation is proposed to reduce this program to a linear program with one 0 1 variable per planning period the performances of the algorithms are studied in two simulation experiments the simulations show that when planning over a rolling horizon the approach proposed yields excellent results

a little fairness may induce a lot of redistribution in democracy we use a model of self centered inequality aversion suggested by fehr and schmidt 1999 to study voting on redistribution we theoretically identify two classes of conditions when an empirically plausible amount of fairness preferences induces redistribution through referenda we test the predictions of the adapted inequality aversion model in a simple redistribution experiment and flnd that it predicts voting outcomes far better than the standard model of voting assuming rationality and strict self interest

poverty economic growth and average exit time a simple transformation of the watts poverty index yields a meaningful measure with appealing ordinal properties and a natural interpretation in terms of the potential for economic growth to alleviate poverty the index is illustrated with data from bangladesh and bolivia 1998 elsevier science s a

on evaluating social welfare by sequential generalized lorenz dominance the sequential generalized lorenz sgl ordering is introduced by atkinson and bourguignon 1987 to rank heterogeneous income distributions it is well known that this ordering has a strong utilitarian support in this note we show that one does not have to be a utilitarian to accept this welfare ordering the sgl ordering is supported by all increasing swfs which record an increase in overall welfare when a cardinal welfare transfer is made from less needy to needier

moral hypocrisy power and social preferences abstract we study how individuals adjust their judgment of fairness and unfairness when they are in the position of spectators before and after making real decisions and how this adjustment depends on the actions they take in the game we find that norms that appear universal instead take into account the players bargaining power also individuals adjust their judgments after playing the game for real money when they behaved more selfishly and only in games where choices have no strategic consequence we interpret this possibly self deceptive adjustment of judgments to actions as moral hypocrisy this behavior appears produced by the attempt to strike a compromise between self image and payoffs so as to release oneself of one s responsibility for selfish behavior

agricultural productivity growth in brazil large and small farms excel abstract the long standing debate on the relationship between farm size and productivity has been generally limited by the range of farm sizes evaluated and the definition of productivity in this paper we use data from three brazilian agricultural censuses to address these issues in particular we introduce a wider distribution of farm sizes than presently available from the literature and we employ total factor productivity tfp as our performance measure in doing so we test which farm size class had the highest tfp levels in 1985 and 2006 how factor productivity growth varied within and across farm size classes between those years and which policy or factor had the greatest productivity enhancing effect when examining tfp growth we move beyond the common decomposition into technical and efficiency changes by identifying the complete distribution of farm productivity performances we find that by 2006 a u shaped distribution of productivity over farm sizes had emerged considerable 1985 2006 tfp growth differences are prevalent positive rates for the majority accompany stagnant or negative rates for some public education investments were associated with faster productivity growth regardless of farm size while technical assistance s positive effect and credit s negative effect were associated with larger farm sizes the role of specialization varied by size

one million miles to go taking the axiomatic road to defining exploitation this paper analyses the marxian theory of exploitation a general axiomatic approach is developed which is appropriate to study the concept of exploitation what it is and how it should be captured empirically two properties are presented that capture some fundamental marxian insights it is shown that contrary to the received view there exists a nonempty class of definitions of exploitation that preserve the relation between exploitation and profits called profitexploitation correspondence principle in general economies with heterogeneous agents complex class structures and production technologies with heterogeneous labour inputs however among the main approaches only the so called new interpretation satisfies the profitexploitation correspondence principle in general jel b51

equity measurement in facility location analysis a review and framework abstract in selecting sites for facilities especially in the public sector the issue of equity is becoming increasingly important beginning with the work of mumphreys et al 1971 mcallister 1976 and savas 1978 a substantial literature has developed that incorporates equity in facility siting decision models despite this level of interest however there has been little agreement in these models as to how equity should be measured further except for some recent works there has generally been little comparison of alternative measures or assesment of their relative value let alone any consensus on the best measure s to use perhaps even more surprising is the great number and variety of measures employed the motivation for this paper is to address these problems and provide for researchers a base from which issues of equity can be included in facility siting models more specifically we seek to review the equity literature as it pertains to facility location assemble the set of measures that have been developed and introduce a framework and common notation for organizing them we also will discuss approaches that can be used to select an appropriate measure of equity

dispersive equity and social risk dispersive equity is concerned with the impact of life threatening risks from alternative policy decisions on homogeneous groups in a population it is not addressed to the disutility of various numbers of fatalities that might occur but rather to how fatalities are distributed over the groups although dispersive equity has long been recognized as an important component of some policy decisions it has received little formal treatment within the matrix of salient factors for such decisions our purpose is to advance its formal development this is done within a formulation based on probability distributions over potential fatality sets the formulation gives rise to four distinct but not independent equity concepts individual risk equity group risk equity dispersive equity and social outcome equity each of these is analyzed but special attention is given to dispersive equity the paper also comments on relationships between total equity and its four components and between total equity and the dis

order quantities for perishable inventory control with non stationary demand and a fill rate constraint abstract we study the practical decision problem of fresh food production with a long production lead time to decide every period e g week how many items to produce when a batch is ready for use its items have a fixed shelf life after which the items become waste in the sense that they cannot be sold anymore the demand for fresh food products is uncertain and highly fluctuating mainly caused by price promotions of retail organisations we focus on cases where a so called cycle fill rate service level requirement applies we investigate the generation of a production plan that fixes the timing and quantity of the production for a finite time horizon to minimise waste one issues the oldest items first i e a fifo issuing policy in case of out of stock sales are lost we model this decision problem as a stochastic programming sp model the objective of our study is to find order quantities for the sp model that approximately meet cycle fill rate service level requirements while keeping outdating low to find approximate solutions for the sp model an milp model is developed the milp model is a deterministic approximation that generates feasible replenishment quantities in less than a second with a scenario based minlp approach optimal solutions are generated for a large sample of demand paths as a benchmark for the milp solutions we show that the milp model is suitable for practical use if the setup cost is such that the replenishment cycles in the production plan are close to or of the same length as the maximum shelf life in those cases the expected total costs are close to the costs of the optimal solution and the average fill rate is close to the required one

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

agricultural policy and productivity evidence from brazilian censuses brazil s economic strategy has shifted hesitatingly during the last several decades from one of producer protection to trade competitiveness exploiting the variations these shifts have afforded we use a sequence of decennial agricultural censuses to examine brazilian policy implications for agricultural competitiveness and efficiency total factor productivity is decomposed into best technology and efficiency elements each subject to policy influence we find technology growth at 4 5 per annum to have been extraordinarily high particularly in the south but because productivity among average producers has fallen rapidly behind that on the technical frontier total productivity growth has been a much more modest 2 6 per year public agricultural research programs most benefit the country s technological leaders widening the gap between frontier and average producer credit education and road construction policies instead narrow that gap credit and road programs especially enhance efficiency in the south where efficiency losses have been greatest jel classification o2 o3

the stochastic dynamic production inventory lot sizing problem with service level constraints abstract this paper addresses the multi period single item inventory lot sizing problem with stochastic demands under the static dynamic uncertainty strategy of bookbinder and tan manage sci 34 1988 1096 in the static dynamic uncertainty strategy the replenishment periods are fixed at the beginning of the planning horizon but the actual orders are determined only at those replenishment periods and will depend upon the demand that is realised their solution heuristic was a two stage process of firstly fixing the replenishment periods and then secondly determining what adjustments should be made to the planned orders as demand was realised we present a mixed integer programming formulation that determines both in a single step giving the optimal solution for the static dynamic uncertainty strategy the total expected inventory holding ordering and direct item costs during the planning horizon are minimised under the constraint that the probability that the closing inventory in each time period will not be negative is set to at least a certain value this formulation includes the effect of a unit variable purchase production cost which was excluded by the two stage bookbinder tan heuristic an evaluation of the accuracy of the heuristic against the optimal solution for the case of a zero unit purchase production cost is made for a wide variety of demand patterns coefficients of demand variability and relative holding cost to ordering cost ratios the practical constraint of non negative orders and the existence of the unit variable cost mean that the replenishment cycles cannot be treated independently and so the problem cannot be solved as a stochastic form of the wagner whitin problem applying the shortest route algorithm

perceptional inequality and preferential judgements an empirical examination of distributional axioms there are two categories of income distribution evaluations first the more or less value free perception of income inequality as a statistical dispersion and second the valuation of income distributions according to an explicit social welfare function which is meant to capture all of society s value judgements these societal value judgements can be expressed in the form of preferences whereas the inequality perception of income distributions appeals to an observer s sober judgement the revelation of preferences with respect to specific income distributions appeals to his or her sentiments

explaining interstate variation in income inequality this paper investigates interstate variation in income inequality by avoiding inequality indices and focusing directly on the lorenz curve the authors provide a more general explanation of the differences in inequality they find that mean family income the standard deviation of years of schooling per capita educational expenditure and property income are robust predictors of inequality of particular interest is their finding that ceteris paribus higher per capita education expenditures tend to be associated with states that have income inequality which is greater than the u s average copyright 1992 by mit press

optimal dynamic procurement policies for a storable commodity with levy prices and convex holding costs abstract in this paper we study a continuous time stochastic inventory model for a commodity traded in the spot market and whose supply purchase is affected by price and demand uncertainty a firm aims at meeting a random demand of the commodity at a random time by maximizing total expected profits we model the firm s optimal procurement problem as a singular stochastic control problem in which controls are nondecreasing processes and represent the cumulative investment made by the firm in the spot market a so called stochastic monotone follower problem we assume a general exponential levy process for the commodity s spot price rather than the commonly used geometric brownian motion and general convex holding costs we obtain necessary and sufficient first order conditions for optimality and we provide the optimal procurement policy in terms of a base inventory process that is a minimal time dependent desirable inventory level that the firm s manager must reach at any time in particular in the case of linear holding costs and exponentially distributed demand we are also able to obtain the explicit analytic form of the optimal policy and a probabilistic representation of the optimal revenue the paper is completed by some computer drawings of the optimal inventory when spot prices are given by a geometric brownian motion and by an exponential jump diffusion process in the first case we also make a numerical comparison between the value function and the revenue associated to the classical static newsvendor strategy

dynamic poverty decomposition analysis an application to the philippines summary in this paper we propose a new method of poverty decomposition our method remedies the shortcomings of existing methods and has some desirable properties such as time reversion consistency and subperiod additivity our decomposition integrates the existing methods of growth redistribution decomposition and sector based decomposition because it allows us to decompose the change in poverty into growth and redistribution components for each group e g regions or sectors in the economy our decomposition works well in cases where only partial data are available for some periods it is also flexible and can be extended to have the following six components population shift within region redistribution between region redistribution nominal growth inflation and methodological change components the empirical application of the six way decomposition to the philippines for the period 1985 2009 shows that important policies for poverty reduction may differ across regions for example the autonomous region in muslim mindanao would need growth enhancing policies whereas eastern visayas would need policies to improve the income distribution our decomposition method has a wide applicability and may complement the poverty profile approach

inventory models with minimal service level constraints abstract this paper investigates inventory models in which the stockout cost is replaced by a minimal service level constraint slc that requires a certain level of service to be met in every period the minimal service level approach has the virtue of simplifying the computation of an optimal ordering policy because the optimal reorder level is solely determined by the minimal slc and demand distributions it is found that above a certain critical service level the optimal s s policy collapses to a simple base stock or order up to level policy which is independent on the cost parameters this shows the minimal slc models to be qualitatively different from their shortage cost counterparts we also demonstrate that the imputed shortage cost transforming a minimal slc model to a shortage cost model does not generally exist the minimal slc approach is extended to models with negligible set up costs the optimality of myopic base stock policies is established under mild conditions

redistributive effects of minimal equal sacrifice taxation we examine the circumstances under which minimal equal sacrifice taxation reduces income inequality focusing on absolute sacrifice and relative inequality we show that after tax incomes are more equally distributed than before tax incomes and that after tax inequality decreases with the revenue to be raised if and only if the elasticity of the marginal utility of income is decreasing however other things equal after tax inequality is shown to decline as the utility function becomes more concave we investigate next how these conclusions extend when one takes the absolute inequality view and considers that it is the relative loss in utility that has to be equalized across individuals

an experimental test of the concentration index the concentration index is widely used to measure income related inequality in health no insight exists however whether the concentration index connects with people s preferences about distributions of income and health and whether a reduction in the concentration index reflects an increase in social welfare we explored this question by testing the central assumption underlying the concentration index and found that it was systematically violated we also tested the validity of alternative health inequality measures that have been proposed in the literature our data showed that decreases in the spread of income and health were considered socially desirable but decreases in the correlation between income and health not necessarily support for a condition implying that the inequality in the distribution of income and in the distribution of health can be considered separately was mixed

inventory policies for systems with stochastic and deterministic demand we consider a periodic review inventory system with demand arriving simultaneously from a deterministic source and a random source the deterministic demand has to be satisfied immediately and the stochastic demand can be backordered assuming that the stochastic demand is never backlogged if there is stock in the system we prove that a modified s s policy is optimal under general conditions if there is a setup cost if there is a smoothing cost instead of the setup cost we observe that the problem corresponds to a standard model with one source of demand

equity regarding poverty measures differences in needs and the role of equivalence scales the paper investigates the definition of equity regarding poverty measures when there are different household types in the population it demonstrates the implications of a between type regressive transfer principle for poverty measures for the choice of poverty lines and for the measurement of living standard the role of equivalence scales which are popular in empirical work on poverty measurement is clarified ce memoire examine la definition de mesures de pauvrete fondees sur l equite quand existent differents types de menages dans la population on montre les implications d un principe de transfert regressif entre types de menages pour les mesures de pauvrete pour la definition des seuils de pauvrete et pour la mesure du niveau de vie on clarifie le role des echelles d equivalence qui sont d un usage generalise dans les travaux sur la mesure de la pauvrete

unit consistent decomposable inequality measures this paper introduces a new axiom the unit consistency axiom into inequality measurement this new axiom requires the ordinal inequality rankings rather than the cardinal indices to be unaffected when incomes are expressed in different units i argue that unit consistency is an indispensable axiom for the measurement of income inequality when unit consistency is combined with decomposability i show that the unit consistent decomposable class of inequality measures is a two parameter extension of the one parameter generalized entropy class the extended class accommodates a variety of value judgments and includes different types of inequality measures

using imperfect advance demand information in ordering and rationing decisions in this paper we consider an inventory problem with two demand classes having different priorities the appropriate policy of rationing the available stock i e reserving some stock for meeting prospective future demand of preferred customers at the expense of deliberately losing some of the currently materialized demand of lower demand class es relies on the estimation of the future demand utilizing current signals on future demand which we refer to as imperfect advance demand information adi decreases uncertainty on future demand and may help to make better decisions on when to start rejecting lower class demand we develop a model that incorporates imperfect adi with inventory ordering replenishment decision and rationing available stock in a two period setting we show some structural properties solve the rationing problem and propose solution methods based on monte carlo simulation for the ordering problem we conduct numerical tests to measure the impact of system parameters on the expected value of imperfect adi and provide useful managerial insights

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

aggregate poverty measures the way poverty is measured is important for an understanding of what has happened to poverty as well as for anti poverty policy evaluation sen s 1976 pathfinding work has motivated many researchers to focus on the way poverty should be measured a poverty measure argued by sen should satisfy certain properties or axioms and the desirability of a poverty measure should be evaluated by these axioms during the last two decades many researchers have adopted the axiomatic approach pioneered by sen to propose additional axioms and develop alternative poverty measures the objective of this survey is to provide a clarification on the extensive literature of aggregate poverty measures in this survey we first examine the desirability of each axiom the properties of each poverty measure and the interrelationships among axioms the desirability of an axiom cannot be evaluated in isolation and some combination of axioms may make it impossible to devise a satisfactory poverty measure some axioms can be implied by other axioms combined and so are not independent some others are ad hoc and are disqualified as axioms for poverty measurement based on the interactions among axioms we identify the core axioms which together have a strong implication on the functional form of a poverty measure we then review poverty measures that have appeared in the literature evaluating the interrelationships among different measures and examining the properties of each measure the axioms each measure satisfies violates are also summarized in a tabular form several good poverty measures which have not been documented by previous surveys are also included

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

measurement of income inequality experimental test by questionnaire abstract we reconsider some of the basic assumptions of the literature on inequality analysis students views on the meaning of inequality comparisons were elicited by means of a questionnaire involving both numerical and verbal questions the responses suggest that two important axioms the principle of transfers and decomposability are not universally accepted

reign in hell or serve in heaven a cross country journey into the relative vs absolute perceptions of wellbeing abstract questionnaires exploring the relativist vs absolutist perception of wellbeing are administered to 3883 students in eight different countries four low income countries bolivia brazil kenya and laos 1924 respondents and four high income countries italy sweden switzerland and the uk 1959 respondents our data reveal that wellbeing is perceived mainly in relative terms with the strength of relativism being higher for respondents in high income countries however when the satisfaction of some basic needs is at stake the absolutist concern becomes powerful personal characteristics such as gender and background of studies have a significant role in determining respondents perception of wellbeing finally additional insights emerge from our study interpersonal comparisons take place by looking both upward and downward along the income scale not only income ranking but also the magnitude of reference incomes plays a role and the perception of wellbeing is more elastic to absolute rather than relative income

a two stage stochastic programming model for inventory management in the blood supply chain managing inventories in the blood supply chain is a challenging task mainly due to the uncertain nature of the demand for blood units the perishable nature of the blood and a strong subjective bias towards criteria other than cost minimisation in this paper we propose a two stage stochastic programming model for defining optimal periodic review policies for red blood cells inventory management that focus on minimising operational costs as well as blood shortage and wastage due to outdating taking into account perishability and demand uncertainty the adoption of this framework allows the consideration of more general stochastic processes to model the demand uncertainty than approaches currently available in literature moreover this framework renders a model that can be solved efficiently by general purpose off the shelf optimisation software to illustrate the potential benefits of adopting the proposed model to support the definition of optimal blood inventory control policies a case study is presented considering realistic data representing the daily demand for blood which was generated using the average and standard deviation of the demand for eight types of blood results suggest meaningful insights concerning practices that could lead to improvement in the blood supply chain performance in particular we observed that it would be possible to revise the current inventory control policies by reducing current target levels to diminish wastage and total cost without compromising the service level finally the consideration of blood substitutions showed further improvement in the performance of the blood inventory management system

the relation between farm size and farm productivity the role of family labor supervision and credit constraints abstract the paper shows that if the performance of hired farmhands is affected by supervision from family members and if the availability of credit is dependent on the amount of land owned then a systematic positive or negative relationship between per acre yields and farm size will prevail a model with no supervision effects on labor productivity would predict that yields are unaffected by farm size the paper also investigates the relation between land utilization and owned holding size when land rental possibilities are limited results are shown to be compatible with various observed patterns in ldcs