optimal policies for a capacitated two echelon inventory system this paper demonstrates optimal policies for capacitated serial multiechelon production inventory systems extending the clark and scarf 1960 model to include installations with production capacity limits we demonstrate that a modified echelon base stock policy is optimal in a two stage system when there is a smaller capacity at the downstream facility this is shown by decomposing the dynamic programming value function into value functions dependent upon individual echelon stock variables we show that the optimal structure holds for both stationary and nonstationary stochastic customer demand finite horizon and infinite horizon results are included under discounted cost and average cost criteria

order quantity and timing flexibility in supply chains the role of demand characteristics we study how differences in product demand characteristics affect the strategic value of different types of supply chain flexibility for accurate response we propose a single period inventory modelling framework with two ordering opportunities the second order reflects updated demand information and potentially capitalizes on supply chain flexibility we consider two complementary forms of flexibility quantity flexibility in production and timing flexibility in scheduling in this framework we analyze the total inventory cost of a firm for alternate demand types we model functional products through the standard assumption of independent demand over the period fashion driven innovative products through a bayesian model and innovative products with evolving demand through a martingale process the three demand processes exhibit very different behavior with respect to the value of the alternate forms of flexibility we observe that quantity flexibility is of moderate value for functional goods and of high value for fashion driven products for all lead times quantity flexibility is of low value for goods with evolving demand with long lead times but of high value for short lead times alternately we observe timing flexibility is of highest value for functional goods especially for cases of high holding cost and is of lesser value for fashion driven goods it is of least value for goods with evolving demand both quantity and timing flexibility capabilities are required to significantly reduce the relevant supply chain costs for evolving demand innovative goods when the lead times are long

critical number policies for inventory models with periodic data we consider an infinite horizon in problem with stochastic demands where the data vary periodically karlin karlin s 1960a dynamic inventory policy with varying stochastic demands management sci 6 231 258 karlin s 1960b optimal policy for dynamic inventory process with stochastic demands subject to seasonal variations j siam8 611 629 shows that a periodic critical number policy is optimal and presents an algorithm for computing the critical numbers assuming discounted costs here we develop an alternative conceptually simpler approach to these problems the results include a proof of the optimality of such policies for the average cost case and a qualitative description of the behavior of the optimal policy as smoothing fluctuations in the data

managing a noncooperative supply chain with limited capacity we consider a two stage serial supply chain with capacity limits where each installation is operated by managers attempting to minimize their own costs a multiple period model is necessitated by the multiple stages capacity limits stochastic demand and the explicit consideration of inventories with appropriate salvage value functions a markov equilibrium policy is found intuitive profit dominance allows for existence of a unique equilibrium solution which is shown to be a modified echelon base stock policy this equilibrium policy structure is sustained in the infinite horizon a numerical study compares the behavior of the decentralized system with the first best integrated capacitated system the performance of this decentralized system relative to the integrated system across other parameters can be very good over a broad range of values this implies that an acceptable system performance may be attained without the imposition of a contract or other coordinating mechanism which themselves may encounter difficulties in implementation in the form of negotiation execution or enforcement of these agreements we find instances where tighter capacities may actually enhance channel efficiency we also examine the effect of capacity utilization on the system suboptimality

a periodic review production planning model with uncertain capacity and uncertain demand optimality of extended myopic policies increasing product complexity manufacturing environment complexity and an increased emphasis on product quality are all factors leading to uncertainties in production processes these uncertainties are in the form of unplanned machine maintenance varying production yields and rework among others in planning for production an adequate model must incorporate these uncertainties into the representation of the production process this paper treats the aggregate planning problem for a single product with random demand and random capacity in the single period problem random capacity does not affect the optimal policy but results in a unimodal nonconvex cost function in the multiple period and infinite horizon settings order up to policies that are dependent on the distribution of capacity are shown to be optimal in spite of a nonconvex cost in the infinite horizon setting an intuitive description of the situation leads to the notion of a class of extended myopic policies requiring the consideration o

energy efficiency standards for refrigerators in brazil a methodology for impact evaluation abstract in brazil energy efficiency standards for cold appliances was established in 2007 a specified single set of meps minimum energy performance standards for refrigerators freezers and freezer refrigerators was implemented without evaluating its impacts and estimation of potential electricity savings this paper presents a methodology for assessing the impacts of the brazilian meps for cold appliances it uses a bottom up approach to estimate residential end use consumption and to evaluate the energy saving potential for refrigerators the household electricity consumption is projected by modeling appliance ownership using an econometric approach based on the recent household survey data a cost benefit analysis for more stringent standards is presented from the perspective of the society and electricity customers the results showed that even considering the current market conditions high discount rate for financing new efficient equipment some meps options are advantageous for customers the analysis also demonstrates significant cost effective saving potential from the society perspective that could reach 21 twh throughout the period of 2010 2030 about 25 of current residential consumption

optimal policies for multiechelon inventory problems with markov modulated demand this paper considers a multistage serial inventory system with markov modulated demand random demand arises at stage 1 stage 1 orders from stage 2 etc and stage n orders from an outside supplier with unlimited stock the demand distribution in each period is determined by the current state of an exogenous markov chain excess demand is backlogged linear holding costs are incurred at every stage and linear backorder costs are incurred at stage 1 the ordering costs are also linear the objective is to minimize the long run average costs in the system the paper shows that the optimal policy is an echelon base stock policy with state dependent order up to levels an efficient algorithm is also provided for determining the optimal base stock levels the results can be extended to serial systems in which there is a fixed ordering cost at stage n and to assembly systems with linear ordering costs

the hotspots reference routes and research trends of marginal abatement costs a systematic review abstract as one of the most effective means of evaluating environmental policies marginal abatement costs macs have been adopted in a growing body of research this study characterizes the mac related literature from 1993 to 2018 on web of science based on a systematic review bibliometric analysis and mind mapping the results classify the research hotspots into influential factors methods and empirical applications the three most frequently mentioned influential factors are technical change discount rates and energy prices compared with top down models bottom up models including engineering model and expert based method are the most widely used improvements in the former focus on strengthening market behavior effect while those in the latter aim to overcome the weaknesses of negative costs and lack of interaction across measures mac applications focus on environmental policies with two new research areas recently emerging co benefits and sectoral abatement costs furthermore a reference route is proposed by summarizing the applicability of methods and matching relationships among influential factors methods and empirical problems finally potential research directions are summarized based on the identified research hotspots and a similar co word analysis in marginal cost field such as considering the effects of both multiple influential factors and the interaction among factors on maccs

capacitated multi item inventory systems with random and seasonally fluctuating demands implications for postponement strategies we address multi item inventory systems with random and seasonally fluctuating and possibly correlated demands the items are produced in two stages each with its own lead time in the first stage a common intermediate product is manufactured the production volumes in the first stage are bounded by given capacity limits we develop an accurate lower bound and close to optimal heuristic strategies of simple structure the gap between them evaluated in an extensive numerical study is on average only 0 45 we use the model to investigate the benefits of various delayed product differentiation postponement strategies as well as other strategic questions including i the benefits of flexible versus dedicated production facilities ii the trade off between capacity and inventory investments and iii the trade off between capacity investments and service levels

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

optimal production and inventory policy for multiple products under resource constraints we show that a modified base stock policy is optimal for multiproduct infinite horizon production inventory systems where demand for the products is random and the products share a finite resource every period we characterize the optimal policy for the case of homogeneous products because of the difficulty in computing the optimal base stock levels for the heterogeneous case we propose a heuristic that is simple enough for practical applications we present numerical results that suggest that the heuristic yields near optimal solutions

inventory control with markovian capacity and the option of order rejection we consider a stochastic inventory control problem with markovian capacity and the option of order rejection we show its optimal policy to be the combination of a capacity dependent modified base stock production policy and a capacity dependent critical point order acceptance policy when capacity is stochastically monotone we show that the policy parameters change over the current capacity level in an intuitive way all these results can be extended to the infinite horizon case with or without cost discounting our computational study substantiates the benefits from both exploiting the markovian behavior of the capacity and rejecting orders when necessary

evaluating public policy mechanisms for climate change mitigation in brazilian buildings sector abstract this paper applies a multi criteria analysis mca and marginal abatement cost curves macc to evaluate public policies mechanisms to promote the dissemination of energy efficiency ee and on site renewable energy sources res technologies in brazilian buildings sector the objective here is to bring together the advantages of both methods in order to provide more valuable insights to policy makers the mca results show that in the case of more integrative policies which considers for instance potential of jobs creation the mechanisms to foster distributed res and solar water heaters are better ranked than in macc analysis where only cost effectiveness of each option is evaluated other key finding is that 1 there is a significant cost effective potential that could be reached through alternative mechanisms not implemented yet in the country such as public procurement regulation and building codes and 2 minimum energy performance standards meps could be broader in scope and more stringent and include the use of energy in standby mode and tubular fluorescent lamps in particular some important appliances such as large air conditioning devices should have more aggressive meps

large deviations based asymptotics for inventory control in supply chains we consider a model of a capacitated single class supply chain consisting of production facilities stages in tandem external demand is met from the available finished goods inventory maintained in front of the most downstream facility unsatisfied demand is backlogged every stage orders from its upstream facility thus production is constrained by the local production capacity and the availability of upstream inventory we propose production policies in two separate cases 1 when each facility has information about its local inventory only and 2 when each facility has knowledge of the total downstream inventory in case 1 the proposed policy guarantees that stockout probabilities at each stage stay bounded below given constants service level constraints in case 2 the proposed policy minimizes total expected inventory cost subject to desirable service level constraints in both cases the parameters of the proposed policies are obtained analytically based on large deviations asymptotics which leads to drastic computational savings compared to simulation an important feature of our model is that it accommodates autocorrelated demand and service processes both critical features of modern failure prone manufacturing systems we demonstrate that detailed distributional information on demand and service processes which is incorporated into large deviations asymptotics is critical in inventory control decisions we discuss extensions to a multiclass setting and to a model where unsatisfied demand is lost instead of backordered

a non stationary periodic review production inventory model with uncertain production capacity and uncertain demand abstract in this paper we consider a nonstationary periodic review dynamic production inventory model with uncertain production capacity and uncertain demand the maximum production capacity varies stochastically it is known that order up to or base stock critical number policies are optimal for both finite horizon problems and infinite horizon problems we obtain upper and lower bounds of the optimal order up to levels and show that for an infinite horizon problem the upper and the lower bounds of the optimal order up to levels for the finite horizon counterparts converge as the planning horizons considered get longer furthermore under mild conditions the differences between the upper and the lower bounds converge exponentially to zero

risk sharing in supply chains using order bands analytical results and managerial insights abstract this work generalizes and extends a number of basic production inventory models we study a periodic review non stationary markovian production inventory model with stochastic demand and holding and penalty costs all state dependent where goods can be procured from up to two suppliers each supplier quotes a state dependent minimum order quantity moq order capacity c and unit price we concentrate on a base stock policy that is defined by a vector of numbers one for each lead time indexed by the states of the markov chain in certain cases our policy is optimal for the general case we show that there is no simple optimal policy we use infinitesimal perturbation analysis to compute inventory levels within this class for an application motivated by international trade for this application we find that the imposition of minimum and or maximum order quantities provides an effective mechanism for risk sharing the customer guarantees the supplier a minimum order every period at an increased unit price and in exchange the supplier grants an increase in capacity this can more effectively match supply with demand making the entire supply chain more profitable

optimal commodity trading with a capacitated storage asset this paper considers the so called warehouse problem with both space and injection withdrawal capacity limits this is a foundational problem in the merchant management of assets for the storage of commodities such as energy sources and natural resources when the commodity spot price evolves according to an exogenous markov process this work shows that the optimal inventory trading policy of a risk neutral merchant is characterized by two stage and spot price dependent basestock targets under some assumptions these targets are monotone in the spot price and partition the available inventory and spot price space in each stage into three regions where it is respectively optimal to buy and inject do nothing and withdraw and sell in some cases of practical importance one can easily compute the optimal basestock targets the structure of the optimal policy is nontrivial because in each stage the merchant s qualification of high selling and low buying commodity prices in general depends on the merchant s inventory availability this is a consequence of the interplay between the capacity and space limits of the storage asset and brings to light the nontrivial nature of the interface between trading and operations a computational analysis based on natural gas data shows that mismanaging this interface can yield significant value losses moreover adapting the merchant s optimal trading policy to the spot price stochastic evolution has substantial value this value can be almost entirely generated by reacting to the unfolding of price uncertainty that is by sequentially reoptimizing a model that ignores this source of uncertainty

nonconventional renewable energy governance in brazil lessons to learn from the german experience abstract this paper presents a comparative analysis of energy governance regarding nonconventional renewable energy sources ncres in brazil and germany brazil is a world leader in the use of conventional renewable energy sources such as hydro power while germany has been achieving outstanding results in fostering ncres the focus is on two critical issues the legal and regulatory framework and the institutions created to support the ncres market development the comparison shows that despite the very different energy situations and policy drivers valuables lessons can be extracted from the german experience the main lesson for brazil is to think ncres as a strategic opportunity to rely less on fossil fuel and large hydroelectric power plants to decentralize the electric power sector to use the huge solar biomass and wind power potential available in the country and to create a environment friendly ncres industry to this end three critical points were identified 1 the legal and regulatory framework should be improved 2 long term energy planning taking into account social economic and climate issues and 3 the current institutions supporting ncres in brazil should be upgraded and or new ones such as more specific energy agencies should be created

a capacitated production inventory model with periodic demand for a single product single stage capacitated production inventory model with stochastic periodic cyclic demand we find the optimal policy and characterize some of its properties we study the finite horizon the discounted infinite horizon and the infinite horizon average cases a simulation based optimization method is provided to compute the optimal parameters based on a numerical study several insights into the model are also provided

coordination mechanisms of supply chain systems supply chain management scm has become an important management paradigm as supply chain members are often separate and independent economic entities a key issue in scm is to develop mechanisms that can align their objectives and coordinate their activities so as to optimize system performance in this paper we provide a review of coordination mechanisms of supply chain systems in a framework that is based on supply chain decision structure and nature of demand this framework highlights the behavioral aspects and information need in the coordination of a supply chain the identification of these issues points out several directions of future research in this area

value of information in capacitated supply chains we incorporate information flow between a supplier and a retailer in a two echelon model that captures the capacitated setting of a typical supply chain we consider three situations 1 a traditional model where there is no information to the supplier prior to a demand to him except for past data 2 the supplier knows the s s policy used by the retailer as well as the end item demand distribution and 3 the supplier has full information about the state of the retailer order up to policies continue to be optimal for models with information flow for the finite horizon the infinite horizon discounted and the infinite horizon average cost cases study of these three models enables us to understand the relationships between capacity inventory and information at the supplier level as well as how they are affected by the retailer s s s values and end item demand distribution we estimate the savings at the supplier due to information flow and study when information is most beneficial

inventory control in a fluctuating demand environment we present an inventory model where the demand rate varies with an underlying state of the world variable this variable can represent economic fluctuations or stages in the product life cycle for example we derive some basic characteristics of optimal policies and develop algorithms for computing them in addition we show that certain monotonicity patterns in the problem data are reflected in the optimal policies

simultaneous capacity and production management of short life cycle produce to stock goods under stochastic demand this paper derives the optimal simultaneous capacity and production plan for a shortlife cycle produce to stock good under stochastic demand capacity can be reduced as well as added at exogenously set unit prices in both cases studied with and without carryover of unsold units a target interval policy is optimal there is a usually different target interval for each period such that capacity should be changed as little as possible to bring the level available into that interval our contribution in the case of no carry over is a detailed characterization of the target intervals assuming demands increase stochastically at the beginning of the life cycle and decrease thereafter in the case of carry over we establish the general result and show that capacity and inventory are economic substitutes the target intervals decrease in the initial stock level and the optimal unconstrained base stock level decreases in the capacity level in both cases optimal service rates are not necessarily constant over time a numerical example illustrates the results

optimal joint inventory and transshipment control under uncertain capacity in this paper we address the optimal joint control of inventory and transshipment for a firm that produces in two locations and faces capacity uncertainty capacity uncertainty e g due to downtime quality problems yield etc is a common feature of many production systems but its effects have not been explored in the context of a firm that has multiple production facilities we first characterize the optimal production and transshipment policies and show that uncertain capacity leads the firm to ration the inventory that is available for transshipment to the other location and characterize the structure of this rationing policy then we characterize the optimal production policies at both locations which are defined by state dependent produce up to thresholds we also describe sensitivity of the optimal production and transshipment policies to problem parameters and in particular explain how uncertain capacity can lead to counterintuitive behavior such as produce up to limits decreasing for locations that face stochastically higher demand we finally explore through a numerical study when the optimal policy is most likely to yield significant benefits compared to simple policies

a multi criteria evaluation of policy instruments for climate change mitigation in the power generation sector of trinidad and tobago even as small island developing states sids like trinidad and tobago t t increase industrialization and grapple with the challenges of increased pollution few studies provide guidance to policy makers of such countries on appropriate policy measures and instruments that can be implemented to mitigate greenhouse gas emissions here we apply a multi criteria evaluation methodology to ascertain preferences for policy measures and instruments in the power generation sector four broad policy measures and twelve policy instruments are assessed on criteria of environmental performance feasibility of implementation and political acceptability this method proves useful in t t since typical to many sids the intensive data required by other policy assessment methods is unavailable results indicate little difference in preference among the four policy measures thereby indicating that a multi pronged approach on several policy fronts is required the most preferred policy instruments to operationalize measures included provision of subsidies for energy saving technologies creating an industry wide carbon trading scheme and implementing a feed in tariff to increase the use of renewable energy sources this study therefore provides specific insights for policy makers in trinidad and tobago while also providing power generation sector specific guidance to other rapidly industrializing small island developing states

coalition theory and its applications a survey we survey some of the major advances in coalition theory in recent years we then look at the recent applications of the theory in the area of political economy and touch upon some important theoretical and applied open questions in the field

using scheduled ordering to improve the performance of distribution supply chains we study a supply chain with one supplier and many retailers that face exogenous end customer demands the supplier and the retailers all try to minimize their own inventory related costs in contrast to the retailers newsvendor type ordering behavior under which retailers may place orders freely in every period we propose two scheduled ordering policies the scheduled balanced ordering policy sbop and the scheduled synchronized ordering policy ssop under both the sbop and ssop retailers are allowed to order freely only in one period of an ordering cycle and receive fixed shipments in other periods retailers take turns to order freely under the sbop while under the ssop all retailers order freely in the same period with the average supply chain cost per period as the performance measure we identify mathematical conditions under which scheduled ordering policies outperform the newsvendor type ordering through a large scale numerical study we find that scheduled ordering policies are most effective when i the supplier s holding and expediting costs are high and the retailer s backorder cost is small ii the end customer demand variance and correlation are high and iii the supplier s capacity is high in addition we observe that the behavior of the ssop often complements that of the sbop whereas the sbop is better than ssop when the supplier s capacity is low and when the end customer demand correlation level is high the ssop is better when the opposite conditions prevail

public policy analysis of energy efficiency and load management in changing electricity businesses the focus of this paper is 1 the potential effectiveness of the reform of the electricity industry on promoting energy efficiency and load management and 2 the potential effectiveness of newmechanisms for promoting energy efficiency and load management many countries are initiating reforms of their power sectors to stimulate private investment increase operation and management efficiencies and lower the cost of power these countries are unbundling vertically integrated utilities into distinct generation transmission distribution and retail supply companies introducing commercial management principles to government owned monopolies and in many cases transferring operation or ownership to private companies electric industry restructuring may force regulators and policy makers to re examine existing mechanisms for promoting load management and energy efficiency in some cases electric industry restructuring replaces the long standing relationship between a single monopoly provider and protected customer franchise with a new set of relationships among retail electricity suppliers and customers who may now be free to choose suppliers in these types of situations markets not government regulators and utility monopolies are seen as determining future energy production and consumption decisions however it is uncertain whether this type of restructuring will overcome important market barriers to energy efficiency that limit markets for energy efficient products and services from functioning effectively as a result of these barriers a large untapped potential for cost effective energy efficiency investments exists supporters of public policies argue that energy efficiency programs are an appropriate government strategy to capture economic efficiencies that the market cannot secure unassisted r 2002 elsevier science ltd all rights reserved

a production inventory system with markovian capacity and outsourcing option we study the optimal production inventory outsourcing policy for a firm with markovian in house production capacity that faces independent stochastic demand and has the option to outsource we find very simple optimal policy forms under fairly reasonable assumptions in addition when the capacity markov process is stochastically monotone the policy parameters decrease in the firm s current capacity level under additional assumptions all these results extend to the infinite horizon and undiscounted cost cases we analyze comparative statics and the necessity of some technical conditions and discuss when the outsourcing option is more valuable

average cost single stage inventory models an analysis using a vanishing discount approach an important problem in the theory of dynamic programming is that of characterizing sufficient conditions under which the optimal policies for markov decision processes mdps under the infinite horizon discounted cost criterion converge to an optimal policy under the average cost criterion as the discount factor approaches 1 in this paper we provide for stochastic inventory models a set of such sufficient conditions these conditions unlike many others in the dynamic programming literature hold when the action space is noncompact and the underlying transition law is weakly continuous moreover we verify that these conditions hold for almost all conceivable single stage inventory models with few assumptions on cost and demand parameters as a consequence of our analysis we partially characterize for the first time optimal policies for the following inventory systems under the infinite horizon average cost criterion which have thus far been a challenge a capacitated systems with setup costs b uncapacitated systems with convex ordering costs plus a setup cost and c systems with lost sales and lead times

analysis of batch ordering inventory models with setup cost and capacity constraint abstract stochastic periodic review batch ordering inventory problems appear in many industrial settings however few literature deals with the optimal ordering polices for such problems no mention to the inclusion of the fixed ordering cost and the production capacity in this paper we consider a single item periodic review batch ordering inventory system with the consideration of the setup cost and the capacity constraint for each order over a finite planning horizon by proposing several new convex notions we show that a batch based s s policy is optimal for the unlimited ordering capacity case while for the limited ordering capacity case a modified r q policy is optimal for the setting with zero ordering setup cost and a batch based x y band policy for the setting with positive ordering setup cost moreover we analytically study the sensitivity of the policy parameters with respect to the capacity and batch order size and derive the bounds on the optimal policy parameters we further extend our analysis to the infinite horizon setting and show that the structure of the optimal policy remains similar finally the numerical experiments provide some insights into the impact of model parameters on the benefit of reducing the batch size and increasing the ordering capacity and indicate that ignoring batch requirement may lead to a significant cost increment

sustainability guided promotion of renewable electricity generation in recent years the threat of global climate change high fuel import dependence and rapidly rising electricity demand levels have intensified the quest for more sustainable energy systems this in turn has increased the need for policy makers to promote electricity generation from renewable energy sources guaranteed prices coupled with a buy back obligation for electricity fed into the grid is a popular renewables promotion instrument especially in europe more recently driven mainly by electricity market liberalisation efforts quota targets for the share of renewables in combination with tradable green certificates tgc have received considerable attention tgc offer a greater theoretical potential for economic efficiency gains due to price competition and the greater flexibility assigned to the obliged parties while guaranteed prices and tgc schemes support the operation of renewable energy technology systems bidding schemes for renewable energy generation capacity are used to raise economic efficiency on the plant construction side all of these policy instruments suffer from the shortcoming that they do not explicitly account for the often widely varying environmental social and economic impacts of the technologies concerned in this paper we propose a methodology for the design of renewable energy policy instruments that is based on integrated assessment in particular we argue that using participatory multicriteria evaluation as part of the design of renewable energy promotion policies would make it possible 1 to differentiate the level of promotion in a systematic and transparent manner according to their socio ecological economic impact and 2 to explicitly account for the preferences of stakeholders a further problem of existing tgc and bidding schemes is that diversity of supply could be severely diminished if few low cost technologies were allowed to dominate the renewable energy market to ensure a certain diversity of technologies our scheme suggests the use of different technology bands for technologies that are relatively homogeneous with respect to their maturity

a decomposition approach for a class of capacitated serial systems we study a class of two echelon serial systems with identical ordering production capacities or limits for both echelons demands are assumed to be integer valued for the case where the lead time to the upstream echelon is one period the optimality of state dependent modified echelon base stock policies is proved using a decomposition approach for the case where the upstream lead time is two periods we introduce a new class of policies called two tier base stock policies and prove their optimality some insight about the inventory control problem in n echelon serial systems with identical capacities at all stages and arbitrary lead times everywhere is also provided we argue that a generalization of two tier base stock policies which we call multitier base stock policies are optimal for these systems we also provide a bound on the number of parameters required to specify the optimal policy

the applicability of marginal abatement cost approach a comprehensive review abstract the marginal abatement cost mac methodology is widely used in climate change policies policy makers rely on mac to assess feasible strategies and related costs to achieve emission reduction goals this paper introduces a variety of mac methodologies aiming at solving diverse problems which utilizes various calculable logic thus producing different results and implications this study applies a mind mapping method to capture differentiation of mac methods and systematically classify mac methodologies the applicability path analysis was proposed based on principles such as stakeholder type decision making objectives cost concept strategy mode and information scope our goal is to assess the applicability of different methodologies to reduce misuse by policy makers and to serve as a guide for subsequent research which might prompt and lead to the derivation of more consequential results in future studies the results of this study suggest that the complex method is not always better than the simplified method because policy makers are required to select the appropriate method according to the type of information needed it may even be suggested that mac could be reliable by ranking relative value of options compared with baseline rather than focusing on the absolute value of individual measures

bullwhip effect measurement and its implications the bullwhip effect or demand information distortion has been a subject of both theoretical and empirical studies in the operations management literature in this paper we develop a simple set of formulas that describe the traditional bullwhip measure as a combined outcome of several important drivers such as finite capacity batch ordering and seasonality our modeling framework is descriptive in nature as it features certain plausible approximations that are commonly employed in practical inventory systems the results are nonetheless compelling and can be used to explain various conflicting observations in previous empirical studies building on the theoretical framework we discuss the managerial implications of the bullwhip measurement we show that the measurement can be completely noninformative about the underlying supply chain cost performance if it is not linked to the operational details such as decision intervals and leadtimes specifically we show that an aggregated measurement over relatively long time periods can mask the operational level bullwhip in addition we show that masking also exists under product or location aggregation in some illustrative cases