optimal supply diversification under general supply risks we analyze a planning model for a firm or public organization that needs to cover uncertain demand for a given item by procuring supplies from multiple sources the necessity to employ multiple suppliers arises from the fact that when an order is placed with any of the suppliers only a random fraction of the order size is usable the model considers a single demand season with a given demand distribution where all supplies need to be ordered simultaneously before the start of the season the suppliers differ from one another in terms of their yield distributions their procurement costs and capacity levels the planning model determines which of the potential suppliers are to be retained and what size order is to be placed with each we consider two versions of the planning model in the first the service constraint model scm the orders must be such that the available supply of usable units covers the random demand during the season with at least a given probability in the second version of the model the total cost model tcm the orders are determined so as to minimize the aggregate of procurement costs and end of the season inventory and shortage costs in the classical inventory model with a single fully reliable supplier these two models are known to be equivalent but the equivalency breaks down under multiple suppliers with unreliable yields for both the service constraint and total cost models we develop a highly efficient procedure that generates the optimal set of suppliers as well as the optimal orders to be assigned to each most importantly these procedures generate a variety of important qualitative insights for example regarding which sets of suppliers allow for a feasible solution both when they have ample supply and when they are capacitated and how various model parameters influence the selected set of suppliers the aggregate order size and the optimal cost values

dynamic replenishment from two sources with different yields costs and leadtimes abstract we study a single item periodic review inventory system with two sources of supply in house production and outsourcing the two sources differ in yields costs and leadtimes demands in consecutive periods are independent random variables and stockout is fully backlogged our problem is to characterize the optimal dynamic policy that simultaneously determines the in house production quantity and the outsourcing quantity for each period to minimize the total discounted cost we show that the optimal policy for in house production can be characterized by a threshold and the production quantity is decreasing in the starting inventory the optimal outsourcing policy however is more complex and a threshold type policy is only optimal under a more restrictive assumption about the yields comparative statics about the effects of yield uncertainty outsourcing on the optimal policy and cost performance are discussed

impact of uncertainty in the quality of returns on the profitability of a single period refurbishing operation this paper investigates how the profitability of reuse activities is affected by uncertainty regarding the quality of returned products specifically we examine a reverse supply chain consisting of two collection sites and a refurbishing site which faces stochastic demand for refurbished products in a single period setting the quality of returns refurbishing yield becomes known only after the transportation of the products to the refurbishing site we prove that the expected profit function has a unique optimal solution procurement and production quantities and we derive the conditions under which it is optimal to use only one of the collection sites the analysis is supported by numerical results which provide insights regarding the effect of the uncertain yields at the two collection sites and their correlation on optimal decisions and system profitability

the moral limits of predictive practices the case of credit based insurance scores corporations gather massive amounts of personal data to predict how individuals will behave so that they can profitably price goods and allocate resources this article investigates the moral found

economic distribution of budget among producers for fulfilling orders under delivery chance constraints abstract at a common due date k orders with known quantities of the same product should be delivered the product can be manufactured by n producers with stochastic production capabilities random yields the expected capability and its standard deviation increase linearly with the allocated budget according to the pre given plant s capability cost trade off functions our problem is to minimize the total budget and to determine its distribution among the producers in order to ensure the complete fulfillment of all orders in accordance with their pre given confidence levels probabilities necessary and sufficient conditions for the existence of an optimal solution of the considered problem as well as the proof that if the problem has a feasible solution then the optimal solution is unique are provided we propose a method for evaluating the optimal solution and demonstrate it through a numerical example

managing supply uncertainty under supply chain cournot competition abstract we study the cournot competition between two supply chains that are subject to supply uncertainty each supply chain consists of a retailer and an exclusive supplier which has random yield we examine how the levels of supply uncertainty and competition intensity affect the equilibrium decisions of ordering quantity contract offering and centralization choice we show that a retailer should order more if its competing retailer s supply becomes less reliable or if its own supply becomes more reliable a supply chain with reliable supply can take great advantage of the high supply risk of its competing chain furthermore for decentralized chains we characterize the optimal wholesale price contracts with linear penalty under different supply risks and competition scenarios finally we show that supply chain centralization is a dominant strategy and it always makes the customers better off nevertheless if the supply risk is low and the chain competition is intensive centralization could actually decrease the supply chain profit compared with the case where both chains do not choose centralization this results in a prisoner s dilemma on the other hand if the supply risk is high and or the competition level is low centralization always increases the supply chain profit the desirability of supply chain centralization is enhanced by high supply uncertainty or low chain competition

the demand for monitoring technologies the case of trucking this paper examines the demand for on board computers in trucking distinguishing between their incentive and resource allocation improving capabilities i find that monitoring s incentive benefits are high when perquisite taking is attractive to drivers driver effort is important and verifying drivers actions to insurers is valuable these results are consistent with agency theory and suggest that networking applications will raise the productivity and pay of difficult toevaluate workers i also find that monitoring s benefits are disproportionately resource allocation related when managerial decisions are least constrained this suggests that networking applications monitoring capabilities raise the returns to delegation when resource allocation decisions are routine and lower them when they are not

product portfolio management with production flexibility in agribusiness the acquisition of production flexibility is a well documented strategy pursued by many firms to counteract certain operational constraints however these flexibilities can increase the complexity of a production system and the difficulties in managing increased complexity may hinder exploiting the full benefit of flexibility in this paper we consider one such flexibility paradox at an agribusiness firm for an annual 800 million production decision the firm produces a number of products hybrid seeds using limited inventories of several raw materials parent seeds and a production process that is subject to random variations to handle the raw material availability constraint and to partially mitigate the supply risk the firm invests in a costly second production in south america that can be used if the yield in the first production in north america is low we solve this joint problem of raw material allocation and sequential production by reformulating it as a tractable simultaneous optimization

diversification under yield randomness in inventory models abstract in this paper we consider the case of random yield and diversification in two different inventory models it is assumed that two sources suppliers exist who ship an amount which is a random function of the amount requisitioned since they may charge different prices and their reliability in terms of the variance of the yield random variable may be different diversification may be more desirable than using a single supplier we analyze this problem for both the eoq model and the newsboy model analytic results for the optimal order quantities and the minimum cost are obtained for the eoq model convexity of the objective function is also discussed we develop the necessary conditions for the newsboy model and propose an approximate solution technique the concavity of the expected profit function is shown numerical examples are provided for both models

an exact algorithm for the capacitated total quantity discount problem in this paper we analyze the procurement problem of a company that needs to purchase a number of products from a set of suppliers to satisfy demand the suppliers offer total quantity discounts and the company aims at selecting a set of suppliers so to satisfy product demand at minimum purchasing cost the problem known as total quantity discount problem tqdp is strongly np hard we study different families of valid inequalities and provide a branch and cut approach to solve the capacitated variant of the problem capacitated tqdp where the quantity available for a product from a supplier is limited a hybrid algorithm called help heuristic enhancement from lp is used to provide an initial feasible solution to the exact approach help exploits information provided by the continuous relaxation problem to construct neighborhoods optimally searched through the solution of mixed integer subproblems a streamlined version of the proposed exact method can optimally solve in a reasonable amount of time instances with up to 100 suppliers and 500 products and largely outperforms an existing approach available in the literature and cplex 12 2 that frequently runs out of memory before completing the search

optimal replenishment and rework with multiple unreliable supply sources we study a production inventory system with multiple unreliable supply sources through inspection and rework the system can improve the quality of the units received from the supply sources there are two interleaved decisions the replenishment quantities from the sources and the inspection rework quantities among the units received we show the optimal solution to the replenishment decision can be efficiently derived from a greedy algorithm and inspection rework is optimally applied to a single source identified by the algorithm furthermore in the case of linear cost functions it is optimal to place orders from two supply sources i e dual sourcing the results extend to the infinite horizon case where an order up to policy is optimal the model also readily adapts to situations in which the supply imperfection takes the form of a reduced delivery quantity yield loss

selecting a portfolio of suppliers under demand and supply risks we analyze a planning model for a firm or public organization that needs to cover uncertain demand for a given item by procuring supplies from multiple sources each source faces a random yield factor with a general probability distribution the model considers a single demand season all supplies need to be ordered before the start of the season the planning problem amounts to selecting which of the given set of suppliers to retain and how much to order from each so as to minimize total procurement costs while ensuring that the uncertain demand is met with a given probability the total procurement costs consist of variable costs that are proportional to the total quantity delivered by the suppliers and a fixed cost for each participating supplier incurred irrespective of his supply level each potential supplier is characterized by a given fixed cost and a given distribution of his random yield factor the yield factors at different suppliers are assumed to be independent of the season s demand which is described by a general probability distribution determining the optimal set of suppliers the aggregate order and its allocation among the suppliers on the basis of the exact shortfall probability is prohibitively difficult we have therefore developed two approximations for the shortfall probability although both approximations are shown to be highly accurate the first based on a large deviations technique ldt has the advantage of resulting in a rigorous upper bound for the required total order and associated costs the second approximation is based on a central limit theorem clt and is shown to be asymptotically accurate whereas the order quantities determined by this method are asymptotically optimal as the number of suppliers grows most importantly this clt based approximation permits many important qualitative insights

inventory models with random yield in a random environment abstract we consider a single item inventory model which is observed periodically in a randomly changing environment all model parameters are specified by the state of the environment which is assumed to be a time homogeneous markov chain yield is random due to the random capacity of the vendor i e a given order is fully received if the order quantity is less than this capacity otherwise the quantity received is equal to the available capacity the problem is analyzed in single multiple and infinite periods and it is shown that in all cases the optimal policy is the well known base stock policy where the optimal order up to level depends on the state of the environment the results are compared with the solutions of the certain yield model when there is infinite capacity we show that the order up to levels are equal in the single period case however in multiple and infinite periods we order the same or more if the yield is random

single period single product newsvendor model with random supply shock abstract in order to investigate the efficiency of policies made by the industrial administration office iao for short so as to keep market order the authors propose a shocked inventory model of one product with both genuine and counterfeit qualities the checking policies made by the iao are considered to be a random shock for the inventory model by examination of the qualities of the products which will expropriate the counterfeit products the paper makes two contributions first while discussing several conditions the authors provide a basic theory which is a kind of extension of the newsvendor problem and prove some properties of the optimal policies for the shocked inventory model with a fixed random checking rate second the authors give some recommendations as to how the iao can formulate its checking policies an example demonstrates the relationship between checking policies and optimal inventory policies

single versus multiple supplier sourcing strategies successful supply chain management necessitates an effective sourcing strategy to combat uncertainties in both supply and demand in particular supply disruption results in excessive downtime of production resources upstream and downstream supply chain repercussions and eventually a loss in the market value of the firm in this paper we analyze single period single product sourcing decisions under demand uncertainty our approach integrates product prices supplier costs supplier capacities historical supplier reliabilities and firm specific inventory costs a unique feature of our approach is the integration of a firm specific supplier diversification function we also extend our analysis to examine the impact of minimum supplier order quantities our results indicate that single sourcing is a dominant strategy only when supplier capacities are large relative to the product demand and when the firm does not obtain diversification benefits in other cases we find that multiple sourcing is an optimal sourcing strategy we also characterize a non intuitive trade off between supplier minimum order quantities costs and supplier reliabilities finally we examine the robustness of our results through an extensive numerical analysis of the key parameters of our model

a numbers game quantification of work auto gamification and worker productivity technological advances and the big data revolution have facilitated fine grained high frequency low cost measurement of individuals work yet we understand little about the influences of such qu

consumption taxes and precautionary savings financing government spending through lump sum taxes does not distort capital when markets are complete but tends to increase precautionary savings under market incompleteness using flat consumption taxes instead leaves precautionary savings unaffected provided certain conditions on utility are met

cents and sensibility economic valuation and the nature of nature 1 how do we attribute a monetary value to intangible things this article offers a general sociological approach to this question using the economic value of nature as a paradigmatic case and oil spills litigations in france and the united states as real world empirical illustrations it suggests that a full blown sociology of economic valuation must solve three problems the why which refers to the general place of money as a metric for worth the how which refers to the specific techniques and arguments laymen and experts deploy to elicit monetary translations and the then what or the feedback loop from monetary values to social practices and representations

risk pooling through physical probabilistic selling abstract this paper investigates the impacts of a new type of probabilistic selling p s where the retailer orders specific products and package some as a discounted physical probabilistic product ppp rather than merely a virtual choice we call this p s strategy as physical probabilistic selling p p s the price gap between the specific products and the probabilistic product results in demand reshape i e some customers who originally buy specific products will switch to buying the probabilistic product which decreases aggregate demand uncertainty however the price discount decreases the profit margin considering this trade off we develop a three product newsvendor model to address the question of how to set the price for the ppp and make inventory allocation decisions we prove that there are two effects under p p s namely the risk pooling effect due to demand reshape and the risk diversification effect due to inventory flexibility with demand uncertainty p p s can improve the retailer s profit at lower inventory levels with proper demand reshape induced by the optimal price discount p p s is more profitable with smaller product differentiation higher customer price sensitivity higher demand uncertainty and lower package cost with supply uncertainty we demonstrate through numerical studies that p p s is a viable strategy to combat asymmetrical supply risk that yields higher profits and service levels

dynamic replenishment production and pricing decisions in the face of supply disruption and random price sensitive demand abstract we study a joint decision problem for replenishment production pricing strategies in the face of both supply and demand uncertainties the supply of the raw material suffers from a potential supply disruption while the demand for the finished goods is price sensitive and random we assume that the raw material is storable and unfilled demands are fully backordered we characterize the optimal policies for raw material replenishment finished goods production and pricing we find that the optimal replenishment policy is an order up to type for a given finished goods stock level while it is a threshold type for a given raw material stock level for either a given finished goods stock level or a given raw material stock level the optimal production policy is a threshold type and the optimal pricing policy is a modified list price type respectively