Stability in Supply Chain Networks
有关供应链的英语作文
有关供应链的英语作文The supply chain plays a crucial role in the success of a business, as it involves the entire process of producing, distributing, and delivering goods to the end consumer. 供应链在企业的成功中起着至关重要的作用，因为它涉及到整个生产、分销和向最终消费者交付商品的过程。
From sourcing raw materials to delivering the final product, the supply chain encompasses a wide range of activities and stakeholders, including suppliers, manufacturers, distributors, retailers, and transportation providers. 从原材料采购到交付最终产品，供应链涵盖了一系列的活动和利益相关者，包括供应商、制造商、分销商、零售商和运输提供商。
One of the biggest challenges in the supply chain management is the need to balance efficiency and cost-effectiveness with the ever-changing consumer demands and market trends. 在供应链管理中最大的挑战之一是需要在不断变化的消费者需求和市场趋势中平衡效率和成本效益。
Efficient supply chain management can result in reduced lead times, improved product availability, and better customer satisfaction. 高效的供应链管理可以减少交货时间、改善产品供应能力，并提高客户满意度。
Supply chain management 供应链管理
3. Lead time-transportation costs
4. Product variety-inventory
– Delayed differentiation
5. Cost-customer service
– Disintermediation
Trade-offs
Location
Logistics
Determining location of facilities
Deciding how to best move and store materials
Successful Supply Chain
• Trust among trading partners
Large number of parts Cost Quality
CPFR
• Collaborative Planning, Forecasting, and Replenishment
• Focuses on information sharing among trading partners • Forecasts can be frozen and then converted into a shipping plan • Eliminates typical order processing
Supply Chain Benefits and Drawbacks
Problem
Large inventories Long lead times
Potential Improvement
Smaller, more frequent deliveries Delayed differentiation Disintermediation Modular
Stability in Supply Chain Networks
897American Economic Review 2008, 98:3, 897–923/articles.php?doi =10.1257/aer.98.3.897The woollen coat, for example, which covers the day-labourer, as coarse and rough as it may appear, is the produce of the joint labour of a great multitude of workmen. The shepherd, the sorter of the wool, the wool-comber or carder, the dyer, the scribbler, the spinner, the weaver, the fuller, the dresser, with many others, must all join their different arts in order to complete even this homely production.Adam Smith (1776)Following the work of David Gale and Lloyd S. Shapley (1962), matching in two-sided mar-kets has been an active area of research in economics. It has produced a number of successful practical applications, as well as a variety of important theoretical results on the structure of matching markets and on the close links between matching and other areas of economics, such as auction theory and competitive equilibrium theory. This stream of research focuses on mar-kets with two sides: e.g., the marriage market between men and women, the admissions market between colleges and students, or the labor market between firms and workers. Such a market is typically viewed in isolation and interactions with other markets are ignored.In many situations, however, markets can be closely interconnected, and an agent’s behavior in one of them may be directly linked to his behavior and options in another. The preferences of a consulting firm hiring college graduates depend on the number and types of its clients. The menu that a restaurant offers to its customers depends on the availability and prices of inputs from its suppliers. The amount of iron ore that a steel manufacturer wants to buy depends on the amount of steel it plans to sell.Interconnected markets can often be handled by the standard competitive equilibrium approach. That approach, however, is ill-suited for incorporating the discreteness and the high degree of heterogeneity of qualities, preferences, and contracts inherent in many settings. For example, on a macro level, we can talk about the average wage of management consultants and derive predic-tions about its movements in response to various shocks in the economy. Once, however, we look at that labor market more closely, it becomes clear that contracts are unique and personalized, assigning a specific worker to a specific firm, location, and position at a specific salary. These —Stability in Supply Chain NetworksBy Michael Ostrovsky*This paper studies matching in vertical networks, generalizing the theory ofmatching in two-sided markets. It gives sufficient conditions for the existenceof stable networks and presents an algorithm for finding two of them. One isthe best stable network for the agents on the “upstream” end of an industry.The other is best for the agents on the “downstream” end. The paper describesseveral properties of the set of stable networks and discusses applications ofthe theory to the design of matching markets with more than two types of agentsand to the empirical analysis of supply chains. (JEL C78, D85, L14)* Graduate School of Business, Stanford University, Stanford, CA 94305 (e-mail: ostrovsky@). I am especially grateful to Al Roth and Ariel Pakes for advice and encouragement throughout this project and to Drew Fudenberg, Parag Pathak, and Michael Schwarz for detailed comments on an early draft of the paper. I also thank Attila Ambrus, John Asker, Jeremy Bulow, Jerry Green, Kate Ho, Paul Milgrom, Markus Mobius, John Roberts, Tayfun Sönmez, Bob Wilson, Pai-Ling Yin, the coeditor, and anonymous referees for helpful comments and suggestions.898THE AMERICAn ECOnOMIC REVIEWJunE 2008 features are easier to incorporate in a matching framework. The same is true of the restaurant market, the markets for iron ore and steel, and other differentiated markets. Section V talks about several such markets in more detail.This paper generalizes the results and techniques of two-sided matching literature to a partic-ular kind of setting with interconnected markets: supply chain networks. The basic structure of this setting is as follows. An industry includes a number of agents: workers, producers, distribu-tors, retailers, and so on. Some agents supply basic inputs for the industry and do not consume any of the outputs (e.g., wheat farmers are the suppliers of basic inputs in a “farmer S miller S baker S retailer” supply chain). Some agents purchase the final outputs of the industry (e.g., car manufacturers are the consumers of final goods in an “iron ore supplier S steel producer S steel consumer” supply chain). The rest are intermediaries, who get their inputs from some agents in the industry, convert them into outputs at a cost, and sell the outputs to some other agents (e.g., millers, bakers, and steel producers are intermediate agents in the examples above).A key assumption in the two-sided matching literature is that the side to which a particular agent belongs does not depend on market conditions: a man cannot become a woman and a student cannot become a college. Likewise, I assume that the positions of agents in a supply chain are exogenously fixed. Specifically, there is a predetermined upstream-downstream partial ordering on the set of agents: for a pair of agents A and B, either A is a potential direct or indirect supplier for B, orB is a potential direct or indirect supplier for A, but not both; it may also be the case that neither is a potential supplier for the other. This ordering can be very simple, with several “tiers” of firms, each of which buys its inputs from firms in the previous tier and sells its outputs to firms in the next tier. It can also be more complicated, with several alternative technologies, several paths of different lengths connecting the suppliers of basic inputs to the consumers of final outputs, and with firms being able to trade both directly and through inter-mediaries. However, it cannot have cycles: an agent cannot be a direct or an indirect supplier for one of its upstream nodes. Note that if there are no intermediate agents, this setting reduces to a two-sided market.Agents can trade discrete quantities of goods, with the smallest tradeable quantity (the unit of quantity) defined ex ante. For example, one unit may correspond to one million tons of steel, one hour of work, or one loaf of bread. In the Gale-Shapley two-sided marriage market, one unit corresponds to marriage, and each person can “trade” at most one unit. Following the literature on two-sided matching with wages and endogenous job characteristics (Vincent P. Crawford and Elsie Marie Knoer 1981; Alexander S. Kelso, Jr., and Crawford 1982; Alvin E. Roth 1984; John W. Hatfield and Paul Milgrom 2005), units traded in the market are represented by contracts. In my setting, each contract specifies the buyer, the seller, the price (if monetary transfers are involved), and the serial number of the traded unit (if multiple units can be traded). A network is a set of contracts: it specifies who sells what to whom and at what price. Each agent has prefer-ences over sets of contracts in which it is involved as a buyer or a seller: e.g., an intermediate agent’s payoff from such a set depends on the payments it makes for its inputs (specified in its upstream contracts) and receives for its outputs (specified in its downstream contracts), as well as on the cost of converting the inputs into the outputs. For a consumer of final goods, the payoff depends on the utility from the goods it purchases and the payments it makes for these goods.I say that a network is chain stable if there is no upstream–downstream sequence of agents (not necessarily going all the way to the suppliers of basic inputs and the consumers of final outputs) who could become better off by forming new contracts among themselves and possibly drop-ping some of their current contracts. This condition is parallel to pairwise stability in two-sided markets, and is tautologically equivalent to it if there are no intermediate agents in the industry. Note that the concept of stability in networks is not strategic—I do not study the dynamics of net-work formation or “what-if” scenarios analyzed by agents who may be considering temporarilyOsTROVsky: sTABILITy In suppLy CHAIn nETWORksVOL. 98 nO. 3899 dropping or adding contracts in the hopes of affecting the entire network in a way beneficial to them, although these considerations are undoubtedly important in many settings. The concept is closer in spirit to general equilibrium models, where agents perceive conditions surrounding them as given, and optimize given those conditions. Under chain stability, agents also perceive conditions surrounding them as given (i.e., which other agents are willing to form contracts with them, and what those contracts are), and optimize given these conditions.Without restrictions on preferences, the set of stable matchings may be empty even in the two-sided one-to-many setting. A commonly used restriction that is sufficient to guarantee the exis-tence of stable matchings in that setting is the gross substitutes condition of Kelso and Crawford (1982). In the supply chain setting, I place an analogous pair of restrictions on preferences; these restrictions are equivalent to the substitutes condition if there are no intermediate agents in the industry. The restrictions are same-side substitutability and cross-side complementarity. Same-side substitutability is a direct generalization of the gross substitutes condition. It says that when the set of available downstream contracts of a firm expands (i.e., there are more poten-tial customers, or the potential customers’ willingness to pay goes up), while the set of available upstream contracts remains unchanged, the set of downstream contracts that the firm rejects also (weakly) expands. Symmetrically, when the set of available upstream contracts expands and the set of available downstream contracts remains unchanged, the set of rejected upstream contracts also expands.Cross-side complementarity is a new restriction, which specifies how a firm’s purchasing and selling decisions are interrelated, and thus links the markets along the supply chain. This restric-tion can be viewed as a mirror image of same-side substitutability. It says that when the set of available downstream contracts of a firm expands, while the set of available upstream contracts remains unchanged, the set of upstream contracts that the firm forms also weakly expands. Symmetrically, when the set of available upstream contracts expands and the set of available downstream contracts remains unchanged, the set of downstream contracts that the firm forms also weakly expands.The restrictions of same-side substitutability and cross-side complementarity are natural and flexible; however, there are several important types of preferences and production technologies that they rule out. I discuss these restrictions in more detail in Section IA.The main result of the paper states that under same-side substitutability and cross-side com-plementarity, there exists at least one chain-stable network. The proof is constructive: it presents an algorithm for finding such a network. This algorithm is a generalization of the fixed-point algorithms of Hiroyuki Adachi (2000), Federico Echenique and Jorge Oviedo (2004, 2006), and Hatfield and Milgrom (2005), which are in turn generalizations of the Deferred Acceptance Algorithm of Gale and Shapley (1962) and the Salary Adjustment Process of Crawford and Knoer (1981) and are applicable only to two-sided markets.The set of chain-stable networks has some interesting properties. The chain-stable network formed in the constructive proof of the existence theorem is upstream-optimal: it is the most pre-ferred chain-stable network for all suppliers of basic inputs and the least preferred chain-stable network for all consumers of final outputs. A slightly modified algorithm produces the down-stream-optimal chain-stable network. The existence of these side-optimal networks is a gener-alization of the classic result in the theory of two-sided matching, which says that the Deferred Acceptance Algorithm converges to the man-optimal stable matching (Gale and Shapley 1962). Another property of the set of stable matchings in two-sided markets is that adding agents on one side of the market makes other agents on that side of the market weakly worse off and makes the agents on the other side weakly better off, in the two side-optimal stable matchings (Kelso and Crawford 1982; Gale and Marilda Sotomayor 1985). This result can also be extended to the supply chain setting: adding a new supplier of basic inputs to the industry makes other such900THE AMERICAn ECOnOMIC REVIEWJunE 2008suppliers weakly worse off and makes the consumers of final outputs weakly better off at both upstream- and downstream-optimal chain-stable networks. Symmetrically, adding a new con-sumer of final outputs makes other such consumers worse off and makes the suppliers of basic inputs better off.These results are very different from the conclusions of several other papers that discuss gen-eralizations and extensions of two-sided matching, but do not impose the supply chain structure of this paper. Gale and Shapley (1962) show by example that the “problem of the roommates,” whose only difference from the “marriage problem” is the absence of two sides in the market, may fail to have a stable pairing. Ahmet Alkan (1988) shows that the “man–woman–child mar-riage problem,” in which each match consists of agents of three different types, may also fail to have a stable matching. Hernan Abeledo and Garth Isaak (1991) prove that to guarantee the existence of stable pairings under arbitrary preferences, it has to be the case that each agent belongs to one of two classes, and an agent in one class can match only with agents in the other class. Note that there is no contradiction between my results and the result of Abeledo and Isaak: in their setting, matching is one-to-one, and so for a particular agent, all acceptable matches are substitutes for one another. In contrast, in the setting of this paper, some agents are intermedi-aries whose preferences satisfy cross-side complementarity and who therefore do not view all acceptable matches as substitutes. Finally, Hideo Konishi and M. Utku Ünver (2006, Theorem 3) show that in general multi-partner matching problems with bilateral links and responsive pref-erences, several different solution concepts are equivalent to pairwise stability. In their setting, however, the set of stable matchings may be empty.To guarantee the existence of chain-stable networks, I assume that agents’ preferences satisfy the cross-side complementarity and same-side substitutability conditions. A similar restriction on preferences was independently introduced by Ning Sun and Zaifu Yang (2006) in the con-text of exchange economies with two types of heterogeneous indivisible objects, quasi-linear preferences, and continuous prices. From the point of view of each agent, objects of one type are substitutes, while objects of different types are complements. For example, from the point of view of a manufacturing firm, workers and machines are complements, while all workers are substitutes for each other and all machines are also substitutes. Sun and Yang (2006) show that in this model a competitive equilibrium always exists. I discuss the connection between this result and the results of the current paper in Section VC.The rest of this paper is organized as follows. Section I formally introduces the model of matching in supply chains. Section II presents the proof of the main result of the paper: under same-side substitutability and cross-side complementarity, chain-stable networks are guaranteed to exist. Section III studies the properties of the set of chain-stable networks. Section IV dis-cusses chain stability and alternative solution concepts. Section V talks about applications and extensions of the model. Section VI concludes.I. The Model of Matching in Supply ChainsConsider an industry consisting of a finite set A of nodes (firms, countries, agents, work-ers, and so on). An exogenously given “upstream–downstream” partial ordering “s” on this set determines possible trading relationships: a s b stands for b being a downstream node for a and means that a can potentially sell something to b. If a s/ b and b s/ a, then there can be no relation-ship between a and b. By transitivity, there are no loops in the market.Relationships between pairs of nodes are represented by bilateral “contracts.” Each contract c represents one unit of a good sold by one node to another. It is a vector, c 5 1s, b, l, p2, where s [ A and b [ A are the “seller” and the “buyer” involved in the contract, s s b; l [ N is the “serial number” of the unit of the good represented by the contract; and p [ R is the price that the buyerOsTROVsky: sTABILITy In suppLy CHAIn nETWORksVOL. 98 nO. 3901 pays to the seller for that unit. The seller involved in contract c is denoted by s c , the buyer is denoted by b c , and so on.Multiple contracts between a seller and a buyer can represent multiple units of the same good or service, units of different types of goods or services, or both. For instance, if the unit is one ton, and a farmer sells 5 tons of wheat and 10 tons of rye to a miller, then this relationship will be represented by 15 contracts with 15 different serial numbers. The example in Appendix B illustrates the use of serial numbers.The set of possible contracts, C, is finite and is also given exogenously. In the simplest case, it can include all possible contracts between nodes in A, with all possible serial numbers from some finite set, and all possible prices from some finite set. It can also be more complicated: e.g., the US trade embargo on Cuba can be incorporated simply by removing all contracts between the nodes in these countries from set C.Note that this framework, restricted to one “tier” of sellers and one “tier” of buyers, encom-passes various two-sided matching settings considered in the literature. Setting l K constant and p K 0 turns this model into the marriage model of Gale and Shapley (1962), assuming that each agent is allowed to have at most one partner. Setting l K constant turns it into the setup of Kelso and Crawford (1982), assuming that agents on one side are restricted to having at most one link, and into the many-to-many matching model of Roth (1984, 1985) and Charles Blair (1988), assum-ing that agents on both sides are allowed to have multiple links. Setting p K 0 and assuming that all links connecting two nodes are identical turns the model into a discrete version of the schedule matching problem of Mourad Baïou and Michel Balinski (2002) and Alkan and Gale (2003).A. preferencesEach node can be involved in several contracts, some as a seller, some as a buyer, but it can-not be involved in two contracts that differ only in price p, i.e., it cannot buy or sell the same unit twice. Nodes have preferences over sets of contracts that involve them as the buyer or the seller. For example, in the simplest case of quasi-linear utilities and profits, the utility of node a involved in a set of contracts X isV a1X2 5 W a151s c, b c, l c2Z c [ X621 a c[D p c2 a c[U p c,where D 5 5c [ X Z a 5 s c6 and u 5 5c[ X Z a 5 b c6, i.e., D is the set of contracts in X in which a is involved as a seller, and u is the set of contracts in which a is involved as a buyer. W a1·2 rep-resents the utility from the purchased contracts for the consumers at the downstream end of the chain, the cost of producing the sold contracts for the suppliers at the upstream end of the chain, and the cost of converting inputs into outputs for the intermediate nodes.For an agent a[ A and a set of contracts X, let Ch a1X2 be a’s most preferred (possibly empty) subset of X, let u a1X2 be the set of contracts in X in which a is the buyer (i.e., upstream contracts), and let D a1X2 be the set of contracts in X in which a is the seller (i.e., downstream contracts). Subscript a will be omitted when it is clear from the context which agent’s preferences are being considered. Preferences are strict, i.e., function Ch a1X2 is single-valued. In the settings in which it is natural to assume that several different sets of contracts should result in identical payoffs (e.g., when two nodes can trade several identical units of a good), I assume that ties are broken in a consistent manner, e.g., lexicographically: in the case of several identical units of a good, that would imply that seller a prefers contract 1a, b, 1, p2 to contract 1a, b, 2, p2, but would prefer 1a, b, 2, p92 to 1a, b, 1, p2 for any p9 . p.902THE AMERICAn ECOnOMIC REVIEWJunE 2008 Preferences of agent a are same-side substitutable if for any two sets of contracts X and y such that D1X2 5 D1y2 and u1X2, u1y 2, u1X2 \ u1Ch1X22, u1y2 \ u1Ch1y 22, and for any two sets X and y such that u1X2 5 u1y 2 and D1X2, D1y 2, D1X2 \ D1Ch1X22, D1y 2 \ D1Ch1y 22. That is, preferences are same-side substitutable if, choosing from a bigger set of contracts on one side, the agent does not accept any contracts on that side that he rejected when he was choosing from the smaller set.Preferences of agent a are cross-side complementary if for any two sets of contracts X and y such that D1X2 5 D1y 2 and u1X2 , u1y 2, D1Ch1X22, D1Ch1y 22, and for any two sets X and y such that D1X2 , D1y 2 and u1X2 5 u1y 2, u1Ch1X22, u1Ch1y 22. That is, preferences are cross-side complementary if, when presented with a bigger set of contracts on one side, an agent does not reject any contract on the other side that he accepted before.Same-side substitutability is a generalization of the gross substitutes condition introduced by Kelso and Crawford (1982) and used widely in the matching literature. If there are only two sides in the supply chain market, then these two conditions become tautologically equivalent. Cross-side complementarity is a new restriction, which is automatically satisfied in any two-sided mar-ket. In a supply chain setting, it is this restriction that “ties together” the purchasing and selling decisions of a node and thus links the markets along the supply chain. It can be viewed as a mirror image of same-side substitutability: when the set of potential contracts on the node’s one side expands, same-side substitutability says that the set of rejected contracts on that side also expands, while cross-side complementarity says that the set of accepted contracts on the other side expands.It is important to highlight what is allowed and what is not allowed by this pair of assump-tions. One possibility that they rule out is scale economies and production functions with fixed costs, because in those cases a firm may decide not to produce one unit of a good at a certain price, while being willing to produce ten units at the same price, violating same-side substitut-ability. Complementary inputs (or outputs) are also generally ruled out.1 Another possibility that is ruled out is an intermediary with fixed capacity (say, one unit) who can transform an input of type 1 into an output of type 1 or an input of type 2 into an output of type 2, but not both (due to the capacity constraint). An addition of a cheap type-1 input to this intermediary’s set of options may cause him to shift from buying one type-2 input and selling one type-2 output to buying one type-1 input and selling one type-1 output, thus violating cross-side complementarity.In contrast, with substitutable inputs and outputs and decreasing returns to scale, many pro-duction and utility functions can be accommodated. The simplest example is a firm that can take one kind of input and produce one kind of output at a cost, with the marginal cost of production increasing or staying constant in quantity. The input good can come from several different nodes, and the output good may go to several different nodes, with different transportation costs. Much more general cases are possible as well: preferences and production functions with quotas and tariffs, several different inputs and outputs with discrete choice demands and production func-tions, capacity constraints and increasing transportation costs, etc.The interdependencies between different inputs or outputs can be rather complex as well. Consider the following example. A firm has two plants in the same location. Each plant’s capac-ity is equal to one unit. The first plant can convert one unit of iron ore into one unit of steel for q1o or it can convert one unit of steel scrap into one unit of steel for q1s . The second plant can convert one unit of iron ore into one unit of steel for q2o or it can convert one unit of steel scrap into one unit of steel for q2s . Then, for a generic choice of costs and prices, the preferences of this firm will be same-side substitutable and cross-side complementary, even though the firm’s1 See, however, the discussion in Section VC.VOL. 98 nO. 3903OsTROVsky: sTABILITy In suppLy CHAIn nETWORksp references over iron ore and scrap are not trivial. (They cannot be expressed by simply saying that two alternative inputs are perfect substitutes, with one being better than the other by a cer-tain amount x.)This example is an analogue of “endowed assignment valuations” in two-sided matching mar-kets (Shapley 1962; Hatfield and Milgrom 2005), in which each firm has several unit-capacity jobs, each worker has a certain productivity at each job, and each firm has an initial endowment of workers. Even in the two-sided setting, it is an open question whether endowed assignment valuations exhaust the set of utility functions with substitutable preferences, and so it is an open question in the supply chain setting as well.For the remainder of this paper, all preferences are assumed to be same-side substitutable and cross-side complementary, and these restrictions will often be omitted from the statements of results to avoid repetition.B. stable networksIn the model, relationships between the nodes are represented by contracts. I call a collection of relationships between the nodes in a market a network, i.e., a network is simply a set of con-tracts. Let m1a2 denote the set of contracts involving a in network m. Network m is individually rational if, for any agent a, Ch a1m1a22 5 m1a2, i.e., no agent would like to unilaterally drop any of his contracts.The most widely used solution concept in the two-sided matching literature is pairwise sta-bility. Its analogue in the supply chain setting is chain stability, defined as follows. A chain is a sequence of contracts, 5c1, … , c n6, n $ 1, such that for any i , n, b c i 5 s c i11, i.e., the buyer in contract c i is the same node as the seller in contract c i11. Note that the chain does not have to go all the way from one of the most upstream nodes in the market to one of the most downstream nodes; it can connect several nodes in the middle of the market. For notational convenience, letb i; b ci and s i;s ci. For a network m, a chain block is a chain 5c1, … , c n6 such that• 5i # n, c i[/m,• c1[ Ch s11m1s1 2<c12,• c n[ Ch bn1m1b n2<c n2, and• 5i , n, 5c i, c i116,Ch b i 5 s i111m1b i2<c i<c i112.In other words, a chain block of network m is a downstream sequence of contracts not belonging to m, in which the buyer in one contract is the seller in the next one, such that each node involved in these contracts is willing to add all of its contracts in the sequence to its contracts in m, pos-sibly dropping some of its contracts in m. A network is chain stable if it is individually rational and has no chain blocks.Note that chain stability is not a strategic concept—each node views the set of contracts avail-able to it as exogenously given and maximizes its payoff given that set, analogously to how con-sumers in a competitive equilibrium choose quantities taking prices as given. Hence, each node treats its contracts independently of one another, ignoring the effect of forming one contract on other nodes’ willingness to pay for other contracts. For example, if a market consists of one seller (whose marginal cost is increasing in quantity) and one buyer (whose marginal benefit is decreas-ing in quantity), then chain stability implies that the number of units traded between these two agents is determined by the intersection of their marginal cost and marginal benefit curves. In more general networks, nodes also ignore various sorts of externalities they may impose on others (e.g., limiting the supply of inputs available to competitors by buying too much and thus reducing the competition in the market for outputs). Hence, the model is not directly applicable。
供应链中的牛鞭效应与库存控制
供应链中的牛鞭效应与库存控制摘要：供应链管理是一项全球化的重要经营战略，在管理中，重要的是了解供应链中的牛鞭效应以及库存控制。
本文旨在探讨供应链管理中的牛鞭效应和库存控制的相关理论、影响因素和解决方法。
为了达到此目的，本文首先阐述了牛鞭效应的定义，同时探讨了牛鞭效应对供应链管理能力的影响及其反应周期，以及其增加库存成本的原因。
我们还将介绍一些解决牛鞭效应的策略，如信息共享、订单流调整和库存管理，以帮助企业有效地优化其供应链。
随后，本文进一步探讨库存控制，包括库存管理的三个核心方面：订单点管理、定量补货和ABC分类法。
此外，我们还将介绍一些库存控制的挑战，如供应稳定性和需求不确定性，以及解决这些挑战的方法，例如应用预测分析和销售预测等技术。
最后，本文结合实际案例，重点分析了牛鞭效应和库存控制实践的自我评估工具。
该工具可帮助企业评估其实践的成熟度以及改进的方向，以更好地应对供应链中的牛鞭效应和库存控制问题。
关键词：牛鞭效应、库存控制、供应链管理、订单点管理、定量补货Abstract：Supply chain management is an important global business strategy, and understanding the bullwhip effect and inventory control in the supply chain is crucial in management. This paper aims to explore the relevant theories, influencing factors, and solutions of the bullwhip effect and inventory control in supply chain management.To achieve this goal, this paper first explains what is the bullwhip effect, the impact of the bullwhip effect on supply chain management capabilities and its reaction cycle,as well as the reasons for increased inventory costs. We also introduce some strategies to solve the bullwhip effect, suchas information sharing, order flow adjustment, and inventory management to help companies effectively optimize theirsupply chains.Furthermore, this paper further explores inventory control, including three core aspects of inventory management: order point management, quantity replenishment, and ABC classification. In addition, we introduce some challenges of inventory control, such as supply stability and demand uncertainty, and how to address these challenges, such as applying forecasting analytics and sales forecasting techniques.Finally, based on practical cases, this paper focuses on the self-assessment tools of the bullwhip effect andinventory control practices. This tool can help companies assess their practice maturity and improvement directions to better address the bullwhip effect and inventory controlissues in the supply chain.Key words: bullwhip effect, inventory control, supply chain management, order point management, quantity replenishment导言随着全球化交易和信息技术的发展，供应链管理成为企业竞争中至关重要的战略。
经贸合作的英语作文
经贸合作的英语作文Title: Enhancing Economic and Trade Cooperation。
In the contemporary global landscape, economic andtrade cooperation plays a pivotal role in fostering growth, prosperity, and mutual benefits among nations. It serves as a catalyst for innovation, development, and the exchange of goods and services across borders. This essay delves into the significance of economic and trade cooperation,exploring its multifaceted benefits and strategies for its enhancement.First and foremost, economic and trade cooperation facilitates the optimal allocation of resources on a global scale. Through the exchange of goods and services,countries can capitalize on their comparative advantages, thereby enhancing efficiency and productivity. This, in turn, leads to increased output, lower costs, and improved standards of living for participating nations. Additionally, such cooperation encourages specialization, allowingcountries to focus on industries where they have a competitive edge, leading to heightened competitiveness in the global marketplace.Furthermore, economic and trade cooperation fosters interdependence among nations, promoting peace andstability. By engaging in mutually beneficial trade relationships, countries become reliant on each other for essential goods and services. This interdependence creates strong incentives for diplomatic dialogue and conflict resolution, as disruptions in trade could have adverse effects on all parties involved. As a result, economic and trade cooperation acts as a stabilizing force ininternational relations, mitigating tensions and fosteringa conducive environment for peaceful coexistence.Moreover, economic and trade cooperation serves as a vehicle for technology transfer and innovation diffusion. Through trade partnerships and foreign investments,countries gain access to new technologies, expertise, and best practices from their trading partners. This influx of knowledge spurs innovation and upgrades domestic industries,enhancing their competitiveness in the global arena. Additionally, cross-border collaboration facilitates research and development initiatives, leading to breakthroughs in various fields and driving economic growth.In light of these benefits, it is imperative to continually enhance economic and trade cooperation through various strategies. Firstly, promoting trade liberalization through multilateral agreements such as free trade agreements (FTAs) and regional economic partnerships can reduce trade barriers and facilitate smoother flows ofgoods and services. By eliminating tariffs, quotas, andother trade barriers, countries can expand market access, stimulate trade flows, and reap the benefits of comparative advantage.Secondly, enhancing connectivity and infrastructure development is essential for facilitating trade and investment flows. Investments in transportation networks, logistics hubs, and digital infrastructure can reduce transaction costs, improve supply chain efficiency, and enhance market access for businesses. Moreover, initiativessuch as the Belt and Road Initiative (BRI) aim to promote infrastructure connectivity and economic integration across regions, fostering trade and development along key trade routes.Additionally, fostering a conducive business environment through regulatory reforms, investment promotion, and institutional capacity-building is crucial for attracting foreign investment and facilitating trade. Streamlining administrative procedures, protecting intellectual property rights, and ensuring legal certainty can instill confidence among investors and businesses, encouraging greater participation in cross-border trade and investment activities.Furthermore, promoting sustainable development and inclusive growth should be integral to economic and trade cooperation efforts. Embracing green technologies, promoting sustainable practices, and ensuring social inclusivity can mitigate environmental degradation and address socio-economic disparities. By prioritizing sustainability and inclusivity in trade and investmentpolicies, countries can achieve long-term prosperity while safeguarding the planet and promoting social equity.In conclusion, economic and trade cooperation holds immense potential for driving global prosperity, fostering peace, and advancing sustainable development. By leveraging the benefits of economic interdependence, promoting trade liberalization, enhancing connectivity, and embracing sustainable practices, countries can unlock new opportunities for growth and collaboration. As we navigate an increasingly interconnected world, prioritizing economic and trade cooperation remains imperative for building a brighter and more prosperous future for all.。
50本电力经典书籍 -回复
50本电力经典书籍-回复「50本电力经典书籍」是一个非常具有挑战性的主题，因为电力工程这一领域没有像文学或者历史等领域一样广为人知的经典著作。
然而，我们可以通过对电力工程相关主题的深入研究，找到一些经典书籍，这些书籍对于电力工程师、学生和研究人员来说都是不可或缺的资源。
电力工程是涉及电力生成、传输、配电和电力系统运营的学科。
在这个广阔的领域中，有许多书籍提供了有关发电、配电、传输线路、电力系统规划、保护和控制等方面的知识。
从基础原理到应用实践，以下是50本被广泛认可的电力工程经典书籍：1.《电力系统分析》（Electric Power Systems Analysis）- John J. Grainger, William D. Stevenson这本书作为电力工程领域的经典教材，涵盖了电力系统分析的许多基本原理。
2.《电力系统稳定》（Power System Stability）- Edward Wilson Kimbark 这本参考书为电力系统稳定性提供了深度的理论和实践知识。
3.《电力系统保护》（Protective Relaying）- J. Lewis Blackburn, Thomas Domin该书详细介绍了电力系统保护的原理和技术。
4.《电力系统的有功和无功控制》（Active and Reactive Power Control of Electric Power Systems）- Takashi Kaneda该书介绍了有关有功和无功控制的先进方法和技术。
5.《电力电子和电力驱动系统: Fundamentals and Hard-switching Converters》- Bimal K. Bose这本书提供了电力电子和电力驱动系统的基础知识，深入讨论了硬开关变换器。
6.《电离害电、地欠电压与电网故障》(Electromagnetic Transients in Power Systems) - R.D. Begamudre该书详细介绍了电磁暂态现象对电力系统的影响以及如何控制它们。
乔普拉《供应链管理(第7版)》每章讨论题及答案CH3
CHAPTER THREEDiscussion Questions1.How could a grocery store use inventory to increase the responsiveness of thecompany’s supply chain?The logistical driver of inventory encompasses all raw materials, work in process, and finished goods within a supply chain. A grocery store can be more responsive in the eyes of its customers if it offers a broader variety of SKUs and/or maintainsa greater quantity of each SKU. A greater quantity of each SKU is problematic forhighly perishable items such as produce, meat, and fish. For these items, a grocery store supply chain should be set up to permit frequent orders so that freshness is ensured and a stockout situation won’t exist for a significant length of time. A grocery store supply chain should use historical demand patterns for seasonalitems to relieve stress on all members and provide customers with product during peak demand periods.2.How could an auto manufacturer use transportation to increase the efficiency ofits supply chain?Transportation, a logistical driver, entails moving inventory from point to point in the supply chain. The trade-off in transportation is between the cost oftransportation and the speed at which product is transported. Slower modes of transportation reduce cost, but could be a reasonable approach if suppliers are co-located with the assembly operations. If the supply chain is designed in such a way, and assembly operations are located with proximity to markets, then thesupply chain can be run cheaply without holding too much inventory in transit.Efficiency can also be improved by aggregating multiple deliveries or pickups ona single truck as done by Seven-Eleven. Transportation efficiency can also beimproved by including an intermediate cross-docking location.3.How could a bicycle manufacturer increase responsiveness through its facilities?Facilities, another logistical driver, are the actual physical locations in the supply chain network where product is stored, assembled, or fabricated. A facility that is designed to be flexible can respond quickly to market demands by retooling to produce different models or products, whereas a dedicated facility cannot.Locating a facility close to the market will increase responsiveness at the cost of decreased economies of scale that might be achieved with a centralized location.A facility that is under capacity will be less responsive than a facility that isappropriately sized or has excess capacity.4.How could an industrial supplies distributor use information to increase itsresponsiveness?Information is a cross-functional driver and consists of data and analysisconcerning facilities, inventory, transportation, costs, prices, and customersthroughout the supply chain. Information serves as a connection among allmembers of the supply chain and operates within each member to facilitateinternal operations. Accurate information can improve responsiveness by helping an industrial supplier better match supply and demand. Information that isgathered farther down the supply chain can be transmitted instantaneously and accurately to the supplies distributor. Instead of waiting for a human to call or FAX an order, the distributor can replenish inventory to the necessary levels or provide what is needed to fill the order as it is realized. For example, a link to planned maintenance schedules of its customers can allow the distributor toensure that parts are available in the right quantity at the right time.5.Motorola has gone from manufacturing all its cell phones in-house to almostcompletely outsourcing the manufacturing. What are the pros and cons of the two approaches?Sourcing is the set of business processes required to purchase foods and services.These decisions are crucial because they affect the level of efficiency andresponsiveness that Motorola can achieve. The Motorola production system for their line of pagers was hailed as a breakthrough in mass customization, so it was somewhat surprising when Motorola outsourced cell phones. Sourcing decisions should be made based on the total supply chain surplus; if a third party can help the chain achieve greater surplus, then the function is a prime candidate foroutsourcing. Motorola was willing to give up some control and possibly some of its design talent and assembly expertise because it felt that the supplier couldprovide product of an appropriate level of quality with the responsivenessnecessary. Products and services that are outsourced are rarely brought back in-house and should never be tied too closely to the outsourcing party’s corecompetency.6.How can a home-delivery company like Peapod use pricing of its deliveryservices to improve its profitability?Pricing is the process by which a firm decides how much to charge customers for its goods and services. Pricing affects the customer segments that choose to buy the product as well as the customer’s expectations. Peapod can use everyday low pricing of its products to ensure stability in the supply chain, but can influence demand by varying the delivery charges. For example, by establishing a minimum order amount of $50 and charging $10 to deliver an order under $75, Peapodprovides an incentive for a customer to pile on additional items to save on per unit shipping. An order over $100 incurs a delivery fee of $7, which is the lowestdelivery charge for a residential customer.Peapod also varies delivery charges by time of day; evening delivery times on weekdays and morning deliveries on Sunday within narrow windows cost an extra dollar, wider delivery windows are $1 less. The delivery latitude allows Peapod’s delivery drivers to schedule more efficiently thereby increasing profitability.7.What are some industries in which products have proliferated and life cycles haveshortened? How have the supply chains in these industries adapted?The authors cite the example of running shoes increasing from five styles in the early 70s to almost 300 by the late 90s. Other products that have seen anexplosion in variety include personal electronics, beverages, snack and prepared foods, entertainment, tires, and personal services.Supply chains have leveraged information systems, recognized the need tocollaborate on product and process design, and supply chain execution. Thesupply chain stance has shifted toward a partnership orientation from a focus on price negotiations. Some supply chains have also changed product design todecrease the number of parts (essentially reduced the running shoe to a bottom and a top) and changed the production process to customize close to the point of sale. Some startups have used 3D printing for running shoes to providecompletely customized shoes.8.How can the full set of logistical and cross-functional drivers be used to createstrategic fit for a cell phone manufacturer targeting both time sensitive and price conscious customers?The logistical drivers, facilities, inventory, and transportation, and the cross-functional drivers, information, sourcing, and pricing, must be used in concert to achieve the appropriate balance of efficiency and responsiveness for the supply chain to be successful. A cell phone manufacturer that wants to deliver product both quickly and efficiently can make cost and time trade-offs among thesedrivers to achieve their goals. These trade-offs across drivers afford moreflexibility but require constant vigilance as the trade-offs within each driverchange. In addition, some drivers may be altered more easily, for example, order quantity and transportation media, than other drivers, for example, location and sourcing.The trade-offs within each driver are summarized in the table:Driver More Responsive More EfficientFacilities Multiple PlantsFlexible Plants Single Plant Dedicated PlantInventory Higher Inventory Lower Inventory Transportation Higher Speed Lower Speed Information Accurate Less AccurateReal-Time Transmission Batched Transmission Sourcing Responsive supplier Efficient supplierPricing Differential Pricing Everyday Low Pricing9.On which supply chain drivers should a firm trying to shrink its cash-to-cashcycle focus?The overall cash-to-cash cycle time (or Days Working Capital) is the number of days of working capital required for a company to operate:Days Working Capital = (Days Inventory Outstanding + Days Sales Outstanding) − Days Payable OutstandingWhere,Days Inventory Outstanding (DIO) = Inventory / (Revenue / 365)Days Sales Outstanding (DSO) = (Account Receivables / Revenue) / 365Days Payable Outstanding (DPO) = (Account Payables / Revenue) / 365The most important thing for a company to remember is that its DSO is its supplier’s DPO—a change in one impacts the other. For example, it’s a common practice for large companies to try to extend payables to improve the cash-to-cash cycle. Some companies will move from using Sight Letters of Credit to Open Account with 30 day payment terms or stretch their Open Account 30 day terms out to 45 or 60 days. Though this will improve the company’s DPO ratio, it will also affect their suppliers who will have to respond to a ballooning DSO.Days Inventory Outstanding is the final component of the cash-to-cash cycle and the most closely tied to the physical supply chain. Any given extended supply chain is going to require some level of inventory to fulfill customer service levels, keep manufacturing processes running, and buffer variability in the physical world. When strategizing inventory, there are two critical questions that need to be answered: •Where should inventory be held or stored in the extended supply chain? •What is the critical balancing point between necessary inventory and waste thatneeds elimination?10. Would you expect a brick-and-mortar retailer or an online retailer to have a higher asset turnover? Which supply chain drivers impact asset turnover?Although the initial response of most students will be an online retailer, we must remind them that they need to look at the overall supply chain drivers and metrics that affect asset turnover. They will confuse choice with availability when comparing a brick-and-mortar retailer to an online retailer. Although true that an online retailer can appear to have more choices for the shopper, the availability of those choices still comes down to how much physical inventory does an online retailer really has instock. Remind them of experiences they have had with ordering online to only receive an out-of-stock message when actually adding the item to their “shopping cart”. Most studies have shown, that an online retailer, on average has a slightly higher asset turnover, this advantage shrinks when it comes to availability and response time.An excellent example is the comparison of Costco and Amazon. Even though Costco is a brick-and-mortar retailer, it achieves excellent asset turns because it only sells a small variety of fast moving products through large stores. In contrast, Amazon sells a wide variety of product, some of which is slow moving. As a result, Costco’s asset turns are comparable or marginally better than Amazon’s.A supply chain is an integrated entity that is a result of its facilities, inventory, transportation, information, sourcing, and pricing and how these items function together, all of these drivers impact asset turnover. The degree to which they impact, relies in the overall strategy of the company in relationship to its customers, suppliers, and financial ownership. In particular, facilities (through PP&E) and inventory are the biggest components of assets.。
供应链 英语描述
供应链英语描述In the modern era of globalization, supply chain management has become a crucial aspect of any business operation. It involves the coordination of activities across multiple organizations, from suppliers to end customers, to ensure the efficient flow of goods and services. This integrated process encompasses procurement, production, logistics, sales, and customer service, all of which must work in harmony to maximize value and minimize waste.The supply chain begins with suppliers, who provide raw materials and components necessary for production.Effective supplier management involves evaluating and selecting reliable partners, negotiating contracts, and monitoring performance to ensure timely delivery of quality products. Strong supplier relationships are essential for maintaining the stability and efficiency of the supply chain.Production is the next phase, where raw materials are transformed into finished goods. This process requires careful planning and execution, taking into account factorssuch as capacity, demand, and lead times. Effective production management ensures that products are made efficiently, cost-effectively, and to the required quality standards.Logistics, which includes transportation, warehousing, and distribution, is crucial for getting products to customers. Efficient logistics systems minimize transportation costs, reduce inventory holding costs, and ensure timely delivery. The use of advanced technologies like just-in-time delivery, lean logistics, and supply chain analytics can further optimize the logistics process. Sales and customer service are the final links in the supply chain, where businesses engage directly with customers. Effective sales and customer service strategies enhance customer satisfaction and loyalty, driving revenue growth and profitability. A responsive customer service team can also help identify and address issues in the supply chain, improving overall performance.In today's dynamic business environment, supply chain management must be agile and responsive to changes in demand, supply, and market conditions. The integration ofadvanced technologies like artificial intelligence, blockchain, and the Internet of Things is transforming supply chain management, enabling real-time tracking and tracing, predictive analytics, and improved decision-making. However, supply chain management also faces challenges such as risks associated with supplier failure, natural disasters, and geopolitical events. Effective risk management strategies, including diversification of suppliers, contingency planning, and resilience building, are crucial for mitigating these risks and ensuring the continuity of the supply chain.In conclusion, supply chain management is a complex yet critical aspect of modern business operations. It requiresa holistic approach, encompassing all stages of the supply chain from suppliers to customers. By leveraging advanced technologies and implementing effective risk management strategies, businesses can optimize their supply chains, drive growth, and enhance customer satisfaction in a globalized world.**供应链管理：全球视角**在全球化的现代时代，供应链管理已成为任何业务运营的关键方面。
供应链网络系统牛鞭效应的有限时间控制
络的鲁棒控制问题[7]。基于系统稳定性理论，李翀运用线性 矩阵不等式的方法，讨论了存在时滞因素情况下牛鞭效应控 制策略[8]。进一步，李翀综合考虑需求、生产能力、供应链 结构、运作时滞等内外不确定因素，并结合经济性能约束， 提出了基于库存水平波动状态的牛鞭效应控制策略[9]。模糊 自适应控制和预测控制等先进控制理论也被应用到供应链牛 鞭效应控制[10]。然而上述文献中控制策略都是在李亚普诺夫 意义下得到的。在控制理论研究中，人们所关心的系统稳定 性主要是李亚普诺夫稳定性，而李亚普诺夫稳定性刻画的是 系统的稳态性能，它并不能反映系统的暂态性能 。 [11-12] 因 此，为了研究系统的暂态性能，有必要讨论系统的有限时间 稳定性。
2013 年 12 月 （第 27 卷第 12 期）
●营销实践
East China Economic Management
Dec.，2013 （Vol.27，No.12）
【DOI】10.3969/j.issn.1007-5097.2013.12.021
供应链网，孙业国 b
LI Linga, SUN Ye-guob
(a. School of Economics and Management；b. Department of Mathematics, Huainan Normal University, Huainan 232038, China) Abstract：This paper mainly studies tactful policy related to finite time control of the bullwhip effect supply chain network system. Firstly, it constructs a state transition model of supply chain inventory network system in an uncertain environment.
与供应商建立联系的英语作文
与供应商建立联系的英语作文Establishing Connections with SuppliersIn the dynamic business landscape, the relationship between a company and its suppliers plays a vital role in ensuring the smooth and efficient flow of operations. Developing strong connections with suppliers is a strategic imperative that can provide a competitive edge, enhance supply chain resilience, and ultimately contribute to the overall success of an organization. This essay will delve into the importance of establishing connections with suppliers, the key considerations, and the steps involved in cultivating these valuable partnerships.The Significance of Supplier ConnectionsEstablishing robust connections with suppliers offers numerous benefits that can have a profound impact on a company's performance. Firstly, strong supplier relationships can lead to greater supply chain stability and reliability. When a company has well-established connections with its suppliers, it can better anticipate and respond to changes in demand, mitigate disruptions, and ensurea steady flow of essential materials or services. This level of supply chain resilience is particularly crucial in today's volatile and unpredictable business environment.Furthermore, close supplier connections can facilitate improved communication and information sharing. By fostering open and transparent dialogues, companies can gain valuable insights into their suppliers' capabilities, constraints, and upcoming developments. This exchange of information enables better planning, coordination, and decision-making, ultimately leading to more efficient and responsive operations.Another key advantage of supplier connections is the potential for cost savings and optimization. When a company has a strong relationship with its suppliers, it can often negotiate more favorable terms, such as volume discounts, extended payment periods, or priority access to limited resources. This can translate into significant cost savings that can be reinvested back into the business, enhancing its overall competitiveness.Additionally, supplier connections can foster innovation and collaborative problem-solving. By working closely with suppliers, companies can gain access to new technologies, processes, or ideas that can drive product and service improvements. This collaborative approach can lead to the development of unique solutions thatdifferentiate a company from its competitors and create added value for customers.Cultivating Supplier ConnectionsEstablishing and maintaining strong connections with suppliers requires a strategic and proactive approach. Here are the key steps involved in cultivating these valuable partnerships:1. Supplier Identification and EvaluationThe first step in building supplier connections is to identify potential partners that align with the company's strategic objectives, quality standards, and operational requirements. This involves conducting thorough research and evaluating suppliers based on factors such as financial stability, technical capabilities, delivery performance, and overall alignment with the company's values and goals.2. Relationship BuildingOnce suitable suppliers have been identified, the next step is to actively engage in relationship building. This involves regular communication, site visits, joint problem-solving sessions, and the establishment of clear and mutually beneficial agreements. By investing time and effort into these relationships, companies can foster trust, understanding, and a shared sense of purpose with their suppliers.3. Collaborative Planning and ForecastingEffective supplier connections require close collaboration in areas such as demand forecasting, inventory management, and production planning. By sharing information and aligning their processes, companies and suppliers can optimize inventory levels, minimize waste, and respond more effectively to changes in market conditions.4. Continuous Improvement and FeedbackMaintaining strong supplier connections is an ongoing process that requires regular review and refinement. Companies should establish mechanisms for providing constructive feedback, identifying areas for improvement, and collaborating on initiatives that drive continuous enhancement of products, services, and processes.5. Risk Management and Contingency PlanningIn today's complex business environment, effective supplier connections must also include robust risk management and contingency planning. Companies should work closely with suppliers to identify potential risks, develop mitigation strategies, and establish backup plans to ensure the continued flow of critical supplies or services.Overcoming Challenges in Supplier ConnectionsWhile the benefits of establishing strong supplier connections are well-recognized, there can be challenges and obstacles that must beaddressed. These may include cultural differences, conflicting priorities, lack of trust, or resistance to change. Successful companies navigate these challenges through effective communication, collaborative problem-solving, and a willingness to adapt and evolve their supplier relationships over time.ConclusionEstablishing connections with suppliers is a strategic imperative that can provide significant benefits to organizations. By fostering strong relationships, companies can enhance supply chain resilience, optimize costs, drive innovation, and ultimately gain a competitive edge in the marketplace. The process of cultivating supplier connections requires a methodical approach, including supplier identification, relationship building, collaborative planning, and continuous improvement. While challenges may arise, companies that prioritize and invest in their supplier connections are well-positioned to navigate the complexities of the modern business landscape and achieve long-term success.。
供应链风险防范措施有哪些内容和要求呢英文
供应链风险防范措施有哪些内容和要求呢英文Supply Chain Risk Prevention Measures: What Contents and Requirements Are There?In today's highly competitive business environment, supply chains have become increasingly complex and vulnerable to various risks These risks can have a significant impact on the smooth operation and profitability of businesses Therefore, it is crucial for companies to understand and implement effective supply chain risk prevention measures This article will explore the key contents and requirements of supply chain risk preventionOne of the important contents of supply chain risk prevention is the identification and assessment of risks Companies need to analyze the entire supply chain process, including suppliers, production, transportation, storage, and sales Risks can come from various sources, such as natural disasters, political instability, supplier bankruptcies, quality problems, and transportation disruptions By conducting a comprehensive risk assessment, companies can have a clear understanding of potential risks and their possible impactsAfter identifying the risks, companies should establish a risk management plan This plan should include specific risk response strategies For example, for risks with high probability and significant impact, companies may consider taking preventive measures such as signing longterm supply contracts with reliable suppliers, establishing emergencyreserves, or diversifying the supply chain For risks with low probability and limited impact, companies may choose to accept the risks but monitor them closelyAnother critical aspect is supplier management Choosing reliable suppliers is essential to reduce supply chain risks Companies should conduct a detailed evaluation of potential suppliers, considering factors such as their financial stability, production capacity, quality control systems, and reputation Regular supplier audits and performance evaluations can help ensure that suppliers continue to meet the required standardsInventory management is also an important part of supply chain risk prevention Maintaining excessive inventory can tie up capital and increase costs, while too little inventory can lead to production delays and lost sales opportunities Therefore, companies need to find the right balance and use inventory management techniques such as justintime （JIT) and materials requirements planning （MRP) to optimize inventory levels and respond quickly to changes in demandInformation technology plays a vital role in supply chain risk prevention A wellimplemented information system can provide realtime visibility into the supply chain, enabling companies to detect potential problems early and take prompt actions For example, using enterprise resource planning （ERP) systems and supply chain management （SCM) software can help improve communication and coordination among different supply chain partners Furthermore, building a resilient supply chain is crucial This means having the ability to quickly adapt and recover from disruptions Companies can achieve this by developing alternative sourcing options, strengtheningrelationships with key suppliers, and establishing contingency plans for different scenariosIn addition, legal and compliance issues should not be overlooked Companies need to ensure that their supply chain operations comply with relevant laws and regulations, such as trade laws, environmental regulations, and labor standards Noncompliance can lead to legal penalties and reputational damageEffective communication and collaboration among all parties in the supply chain are also essential Sharing information, coordinating efforts, and working together to solve problems can enhance the overall efficiency and risk resistance of the supply chainIn conclusion, supply chain risk prevention requires a comprehensive approach that covers risk identification and assessment, risk management planning, supplier management, inventory optimization, information technology utilization, building resilience, legal compliance, and communication and collaboration By implementing these measures and continuously monitoring and improving the supply chain, companies can better cope with uncertainties and ensure the stability and competitiveness of their operations。
物料即将短缺英语作文
物料即将短缺英语作文In the ever-evolving world of commerce and industry, the concept of material shortage is not a new one. However, the urgency of the situation has been amplified in recent times due to a myriad of factors. This essay aims to delve into the causes of material shortages, the impact on various sectors, and potential solutions to mitigate this issue.Causes of Material Shortages1. Supply Chain Disruptions: The global supply chain has been severely impacted by unforeseen events such as natural disasters, geopolitical tensions, and the ongoing pandemic. These disruptions have caused delays in the delivery of raw materials, leading to shortages.2. Resource Scarcity: Certain materials are finite, and as demand outpaces supply, shortages are inevitable. This is particularly true for non-renewable resources like fossil fuels and certain types of metals.3. Economic Fluctuations: Economic downturns can lead to reduced production capacities, which in turn can result in material shortages as manufacturers struggle to keep up with demand.4. Regulatory Changes: New regulations or trade restrictions can impact the availability of certain materials, as seenwith the recent shifts in trade policies affecting the import and export of goods.Impact on Various Sectors1. Manufacturing: Shortages can lead to production halts, increased costs, and delayed product launches. This can significantly impact a company's bottom line and market share.2. Construction: A lack of materials can delay construction projects, increase costs, and lead to disputes between contractors and clients.3. Consumer Goods: Shortages can lead to price hikes and reduced availability of consumer goods, affecting the purchasing power of the general public.4. Agriculture: Shortages of agricultural inputs such as fertilizers and seeds can lead to reduced crop yields andfood insecurity.Potential Solutions1. Diversification of Supply: Companies should seek todiversify their supply sources to reduce reliance on a single supplier or region.2. Investment in Alternative Materials: Research and development into alternative materials can help to alleviate the pressure on scarce resources.3. Improved Forecasting: Better demand forecasting can help companies to plan more effectively and reduce the risk of shortages.4. Government Intervention: Governments can play a role in ensuring the stability of supply chains through policy and regulation, as well as supporting the development of new materials.In conclusion, material shortages pose a significant challenge to the global economy. However, with proactive measures and a collaborative approach between businesses, governments, and consumers, it is possible to minimize the impact and ensure a more sustainable future.。
医药流通行业供应链金融案例
医药流通行业供应链金融案例The pharmaceutical distribution industry is crucial in ensuring the timely and efficient flow of medicines from manufacturers to end-users. 医药流通行业在确保药品从生产商到最终用户的及时高效流动中起着至关重要的作用。
This industry involves various stakeholders such as manufacturers, distributors, pharmacies, and healthcare facilities, all working together to provide essential medical products to the population. 这个行业涉及到制造商、分销商、药店和医疗设施等多方利益相关者，他们共同努力为人群提供必要的医疗产品。
However, the complex supply chain and high-value products in this industry often lead to financial challenges for businesses operating within it. 然而，这个行业中复杂的供应链和高价值产品往往给业务运营带来财务挑战。
One common issue faced by pharmaceutical distributors is the extended payment terms they have with manufacturers. 医药分销商面临的一个常见问题是与制造商之间的长期付款条款。
Manufacturers may require distributors to pay for products upfront or within a short period, while distributors often have to wait for payment from pharmacies or healthcare facilities which can take several weeks. 制造商可能要求分销商提前支付产品费用，而分销商则经常需要等待来自药店或医疗机构的付款，这可能需要几个星期的时间。
保护中国供应链英语作文
As a high school student deeply interested in global economics, Ive been following the recent discussions about the protection of Chinas supply chains. Its a topic that has gained significant attention due to the global economic shifts and the ongoing pandemic. Heres my take on why safeguarding Chinas supply chains is crucial and what it means for the global economy.Firstly, Chinas supply chains are a backbone of the global manufacturing industry. From electronics to textiles, China has been a hub for production. The intricate network of suppliers and manufacturers in the country ensures that goods are produced efficiently and at a competitive cost. This efficiency is not just beneficial for China but for the entire world, as it helps keep the prices of consumer goods down and contributes to economic growth worldwide.However, the recent global health crisis has exposed vulnerabilities in these supply chains. With factories shut down and transportation disrupted, the flow of goods has been severely impacted. This has led to shortages and delays that have affected businesses and consumers globally. Its a stark reminder that while supply chains are essential, they are also fragile and require protection.To protect these supply chains, China has been taking several measures. One of the key strategies has been to diversify the sources of raw materials and components. By not relying too heavily on a single country or region, the risk of disruption is reduced. This diversification has been a learning curve for many businesses, but its a necessary step towards building moreresilient supply chains.Another important aspect is the promotion of domestic production. By strengthening domestic industries, China can reduce its dependence on foreign suppliers. This not only helps in times of crisis but also contributes to the countrys economic growth. Its a strategic move that can lead to a more selfreliant economy.Technology also plays a crucial role in protecting supply chains. The use of advanced technologies such as AI and IoT can help in better managing and optimizing the supply chain processes. For instance, predictive analytics can help in identifying potential bottlenecks and taking proactive measures to avoid them. This can significantly improve the efficiency and reliability of supply chains.Moreover, China has been investing in infrastructure to support its supply chains. This includes improving transportation networks, upgrading ports, and building new warehouses. These investments not only enhance the logistics capabilities but also create jobs and stimulate economic activity.The protection of Chinas supply chains is not just about safeguarding the countrys economy. Its also about ensuring the stability of the global economy. As a major player in global trade, any disruption in Chinas supply chains can have farreaching consequences. Therefore, its in the interest of all countries to support Chinas efforts in this regard.In conclusion, protecting Chinas supply chains is a complex task thatrequires a multifaceted approach. It involves diversification, domestic production, technological innovation, and infrastructure development. While there are challenges, the potential benefits are immense. By ensuring the stability and efficiency of its supply chains, China can continue to play a pivotal role in the global economy. As a student observing these developments, I am hopeful that these efforts will not only benefit China but also contribute to a more stable and prosperous global economy.。
原材料涨价英语作文
原材料涨价英语作文Title: The Impact of Rising Raw Material Prices。
In recent times, the global economy has been witnessing a significant surge in the prices of raw materials, triggering widespread concerns and debates. This phenomenon has ramifications across various sectors, from manufacturing to consumer goods, with its effects felt by businesses and individuals alike. In this essay, we delve into the causes and consequences of rising raw material prices, exploring the challenges they pose and potential solutions to mitigate their impact.Causes of Rising Raw Material Prices:Several factors contribute to the escalation of raw material prices on the global stage. One primary driver is the imbalance between supply and demand. Rapid industrialization and urbanization in emerging economies have led to soaring demand for key commodities such as oil,metals, and agricultural products. This surge in demand often outpaces the rate at which these resources can be extracted or produced, resulting in supply shortages and subsequently driving prices upward.Furthermore, geopolitical tensions and instability in resource-rich regions can disrupt supply chains, leading to supply disruptions and further exacerbating price volatility. For instance, political conflicts in oil-producing regions or trade disputes between major economies can lead to fluctuations in oil prices, impacting various industries reliant on petroleum-based products.Additionally, natural disasters and adverse weather conditions pose significant challenges to agricultural production, leading to crop failures and shortages. These supply shocks contribute to price spikes in essential commodities like wheat, corn, and soybeans, affecting food prices worldwide.Consequences of Rising Raw Material Prices:The repercussions of escalating raw material prices are multifaceted and extend across different sectors of the economy. One immediate consequence is inflationary pressure, as higher production costs are passed on to consumers inthe form of elevated prices for goods and services. This phenomenon erodes purchasing power, particularly among low-income households, exacerbating income inequality.Moreover, businesses face heightened operational costs, which can squeeze profit margins and hinder investment and expansion plans. Small and medium-sized enterprises (SMEs), in particular, may struggle to absorb these cost increases, leading to financial distress and, in some cases, closure.Furthermore, rising raw material prices can impact employment levels, as companies may resort to workforce reductions or wage freezes to mitigate the effects of cost inflation. This situation adds to socioeconomic challenges, including unemployment and underemployment, contributing to social unrest and political instability.From a macroeconomic perspective, soaring raw materialprices can widen trade deficits for resource-importing countries, as they must allocate a more substantial portion of their export earnings to pay for expensive imports. This imbalance in trade flows can strain foreign exchange reserves and jeopardize economic stability.Mitigating Strategies:Addressing the challenges posed by rising raw material prices requires a multifaceted approach involving stakeholders from government, industry, and civil society. Firstly, policymakers must focus on enhancing resource efficiency and diversifying supply sources to reduce dependency on volatile regions. Investing in research and development of alternative materials and renewable energy sources can also promote sustainability and resilience in the face of price fluctuations.Furthermore, fostering international cooperation and dialogue is essential to mitigate geopolitical tensions and promote stability in resource-rich regions. Diplomatic efforts aimed at resolving conflicts and fostering peacefulcoexistence can help alleviate supply chain disruptions and reduce price volatility.At the corporate level, businesses should adopt proactive risk management strategies, including hedging against commodity price fluctuations and renegotiating contracts with suppliers to secure favorable terms. Embracing innovation and adopting advanced technologies such as automation and data analytics can enhance productivity and mitigate the impact of rising production costs.Additionally, promoting financial inclusion and providing targeted support to vulnerable populations can help mitigate the adverse effects of inflation on households. Social safety nets, such as cash transfer programs and food subsidies, can provide temporary relief and buffer against the impact of rising prices on the most marginalized communities.In conclusion, the phenomenon of rising raw material prices presents significant challenges for economiesworldwide, with far-reaching implications for businesses, consumers, and policymakers. Addressing these challenges requires a concerted effort to promote sustainability, resilience, and inclusive growth. By adopting a collaborative and holistic approach, stakeholders can navigate the complexities of a volatile global economy and pave the way for a more prosperous and equitable future.。
乔普拉《供应链管理(第7版)》每章讨论题及答案CH5
CHAPTER FIVEDiscussion Questions1.How do the location and size of warehouses affect the performance of a firm suchas Amazon? What factors should Amazon take into account when deciding where and how big its warehouses should be?The location and size of Amazon’s warehouses have a direct bearing on howresponsive and efficient they can be. At one time, Amazon ran their onlinebookstore out of one warehouse in Seattle; this wareh ouse was small by today’s standards and was unable to keep up with peak demand. Seattle, on average, is also quite far from customers in America. Amazon has since added othergeographically distributed warehouses that hold the items with steadier demand.The dispersion of warehouses allows Amazon to ship items from closer to the customers and the stocking of items with more even demand allows for a higher service level at a reasonable cost.Amazon should consider what regions with high demand are underserved by the current network of warehouses and where it is most economical to locate the next warehouse, effectively balancing their efficiency and responsiveness with their strategy. Amazon should account for facility, inventory, and transportation costs and the desired level of responsiveness when making its location decisions.2.How do import duties and exchange rates affect the location decision in a supplychain?Tariffs refer to any duties that must be paid when products are moved acrossinternational, state, or city boundaries. If a tariff is excessive, it provides a strong disincentive to do business across borders with entities in that area. The classic workaround to a high tariff is adding a location inside the area. Some regionshave developed trade agreements that limit or eliminate the tariff on goods.Exchange rates specify how much one currency is worth in terms of another. As one currency gains against another, it may be beneficial to add shift production to the area using the devalued currency. This makes the goods more affordable for the population. Companies with flexible production capabilities can shift some production from area to area depending on the buying power of local markets.3.How is a rise in transportation costs likely to affect global supply chain networks?As transportation costs rise, more companies will elect to place facilities closer to the customer in order to lower overall transportation costs. Companies mustweigh these increasing costs against the cost of additional inventory andinfrastructure costs in making the strategic decision where to place facilities. Astransportation costs rise, these decisions will greatly impact overall supply chain profits.4.Amazon has built new warehouses as it has grown. How does this change affectvarious costs and response times in the Amazon supply chain?Logistics and facility costs incurred within a supply chain change as the number of facilities, their location, and capacity allocation is changed. As Amazon has added warehouses, their logistics, inventory and facility costs have changed. An increased number of warehouses increases that fixed facility cost but can beexploited to reduce outbound transportation costs. These potentially fall if thewarehouses are spread throughout a distribution area, which increasesresponsiveness at a similar cost or maintains responsiveness at a reduced cost.Inventory costs also increase with an increased number of warehouses because items have to be held at multiple locations, decreasing the extent of pooling.5.McMaster-Carr sells MRO equipment from five warehouses in the United States.W.W. Grainger sells products from more than 300 retail locations, supported by several warehouses. In both cases, customers place orders using the Internet or on the phone. Discuss the pros and cons of the two strategies.W.W. Grainger has the more responsive network; a customer with a critical repair need can drive to a local retail location to pick up the necessary part. McMaster-Carr’s network is less responsive; critical supplies would be scheduled forovernight delivery in all likelihood. W.W. Grainger has the greater facility cost since it has more locations, although the retail facilities provide a presence that doubles as a marketing tool not enjoyed by McMaster-Carr. McMaster-Carr’sfacility expense is much lower and their network model shifts the transportation cost more fully to the customer. Grainger will, on average, also have higherinventory costs than McMaster. A W.W. Grainger customer travels the last mile to pick up an order, but Grainger must ship from their warehouse to the retaillocations.6.Consider a firm such as Apple or Dell, with few production facilities worldwide.List the pros and cons of this approach and why it may or may not be suitable for the computer industry.The advantage for Dell’s network design is lower facility and inventory costs;they can locate in just enough countries to avoid tariffs and mitigate some of their exchange rate and demand risk. They also get the advantage of economies of scale.The disadvantage for Dell is the lack of responsiveness this adds to their system.A customer has no expectation of zero flow time, so they know as they enter thetransaction that they must wait for their PC. Shipping from one of the production facilities adds to the delay, which is highly visible on Dell’s or the packagecarrier’s web site. The shipping costs might also be a concern for some customers, but the value to shipping cost ratio is so high that these costs seem like smallpotatoes in comparison to the total invoice.7.Consider a firm such as Ford, with more than 150 facilities worldwide. List thepros and cons of having many facilities and why this model may or may not be suitable for the automobile industry.Automakers often use a multiplant strategy to create server facilities. These server facilities provide product for the market where they are located, thereby taking advantage of tax incentives, local content requirements, tariff barriers, and high logistics costs. This can be a good strategy if market demand exists for yourproduct; when demand drops, the producer is left with expensive excess capacity.If the facilities are flexible, production of popular models can continue to prepare product for export. If facilities are inflexible or all sales are flat, then the producer must bear the cost or shed assets. The presence of local facilities also reduces the cost incurred in transporting the final product to the customer.。
supplychainflexibility：供应链弹性
Romanian Economic and Business Review – Vol. 2, No. 1SUPPLY CHAIN FLEXIBILITYSimona Daniela Grigore∗AbstractTo be flexible means to have the ability to vary as you like, according to the needs. Flexibility is the ability to adapt, in a reversible manner, to an existing situation, as opposed to evolution, which is irreversible. Companies must realize the real competition is not firm-to-firm, but supply chain-to-supply chain.IntroductionOne strategy for gaining and keeping a competitive advantage in a dynamic environment is to create a flexible organization.Flexibility is the organization's ability to meet an increasing variety of customer expectations without excessive costs, time, organizational disruptions, or performance losses.To be useful in achieving company objectives, flexibility should be viewed from a value chain perspective (satisfying customer needs) rather than from an equipment or process perspective .From a customer's perspective, cross-functional and cross-company efforts are needed to eliminate bottlenecks, increase responsiveness, and create a level of performance that enables firms to build lasting competitive advantage. Therefore, value chain flexibility is broadly defined to include product development, manufacturing, logistics, and spanning flexibilities.Flexibility may be defined as the ability to change or react with little penalty in time, effort, cost or performance .Flexibility can improve the company's competitiveness, particularly for the decision-making process of implementing technologies .But managers do not have a comprehensive view of flexibility because they focus more on machine flexibility than on total system flexibility.Flexibility in supply chains may well represent a potential source to improve the company's efficiency and may be a significant measure of supply chain performance .Supply chain flexibility is defined to encompass those flexibility dimensions that directly impact a firm's customers and are the shared responsibility of two or more functions along the supply chain, whether internal (marketing, manufacturing) or external (suppliers, channel members) to the firm.Flexibility: concept and typesFlexibility is a complex and multidimensional concept, difficult to summarise. Flexibility is defined as an attribute of a system technology for coping with the variety of its environmental needs.Flexibility reflects the ability of a system to change or react with little penalty in time, effort, cost or performance.∗ Simona Daniela Grigore is Associate Professor at the Romanian American University in Bucharest.There has even been a proliferation of papers that review the flexibility literature. The published reviews consider different aspects of flexibility such as definitions, classification and measurement of flexibility, choices, interpretation and requests for flexibility:•functional aspects (flexibility in operations, marketing, logistics),•hierarchical aspects (flexibility at shop, plant or company level),•measurement aspects (focused on global flexibility measures vs context specific ones),•strategic aspects (centred on the strategic relevance of flexibility),•time horizon aspects (long-term vs short-term flexibility),•object of change (flexibility of product, mix, volume).Flexibility types in the manufacturing literature can be reviewed through different frameworks. The classical approach to flexibility frameworks has a bottom-up structure related to a manufacturing hierarchy with three hierarchical flexibility levels:1.basic- comprise flexibility of the system components: machines, the material handling units and the transporting network.2.system: the basic flexibility types at the manufacturing system level; an important type of system flexibility with implications for the supply chain system is routing flexibility.3.aggregate levels: the aggregated attributes of the manufacturing system technology enabling it to cope with the variety of changes and needs at the strategic level.Supply chain flexibility componentsA complete definition of supply chain flexibility components will include the flexibility dimensions required by all the participants in the supply chain to successfully meet customer demand.Flexibility in the supply chain adds the requirement of flexibility within and between all partners in the chain, including departments within an organization, and the external partners, including suppliers, carriers, third-party companies, and information systems providers. It includes the flexibility to gather information on market demands and exchange information between organizations.Six components of supply chain flexibility have been identified from the literature on manufacturing flexibility, strategic flexibility and the limited writings on supply chain flexibility:1.Operations system flexibility (both manufacturing and service) – ability to configure assets and operations to react to emerging customer trends (product changes, volume, mix) at each node of the supply chain.2.Market flexibility – ability to mass customize and build close relationships with customers, including designing and modifying new and existing products. . A critical need in today’s competitive environment is the ability to design and introduce new products as customers’ needs, materials, and technologies change.3.Logistics flexibility – ability to cost effectively receive and deliver product assources of supply and customers change (customer location changes, globalization, postponement).4.Supply flexibility – ability to reconfigure the supply chain, altering the supply of product in line with customer demand. The flexibility of supply includes flexibility in establishing the relationships with partners. Companies may choose to solicit short-term bids, enter into long-term contracts and strategic supplier relationships, form joint ventures, form consortiums, create problem-solving councils or vertically integrate.anizational flexibility – the ability to align labor force skills to the needs of the supply chain to meet customer service/demand requirements.rmation systems flexibility – the ability to align information system architectures and systems with the changing information needs of the organization as it responds to changing customer demand.Dimensions of supply chain flexibilitySupply chain flexibility takes into account two main aspects:a.process flexibility of each supply chain plant, concerning the number of product types that can be manufactured in each production site (supplier or assembler);b.logistics flexibility, related to the different logistics strategies which can be adopted either to release a product to a market or to procure a component from a supplier.The flexibility dimensions are:a.Product flexibility, defined in a supply chain framework as the ability to handle difficult, non-standard orders, to meet special customer specifications, and to produce products characterised by numerous features, options, sizes, and colours.b.Volume flexibility, defined as the ability to effectively increase or decrease aggregate production in response to customer demand). Volume flexibility directly impacts supply chain's performance by preventing out-of-stock conditions for products that are suddenly in high demand or by preventing high inventory levels.c.Routing flexibility- is the capability of processing a part through varying routes by using alternative machines, flexible material handling, and flexible transporting network; this flexibility reduces the negative impact of environmental uncertainty and unforeseen inefficiencies in the production process.d.Delivery flexibility is the company's capability to adapt lead times to the customer requirements; an example of high delivery flexibility is JIT, when suppliers deliver the products to the customer at the right quantity, place and time.e.Trans-shipment flexibility involves movement of stock between locations at the same echelon level where physical distances between the demand locations and the supply locations are small .f.Postponement flexibility implies the capability of keeping products in their generic form as long as possible, in order to incorporate the customer's product requirements in later stages.g.Sourcing flexibility is related to the company's ability to find another supplier for each specific component or raw material.h. A flexibility dimension suitable to many industries is responsiveness to target markets (response to market flexibility). This flexibility captures the overall ability of the firm to respond to the needs of its target marketsunch flexibility – the ability to rapidly introduce many new products and product varieties is a strategically important flexibility that requires the integration of numerous value activities across the entire supply chain.j.Access flexibility – the ability to provide widespread or intensive distribution coverage. This flexibility is facilitated by the close coordination of downstream activities in the supply chain whether performed internally or externally to the firm.Figure 1. Supply chain flexibility dimensionsSource: Angel Martínez Sánchez, Manuela Pérez PérezConclusionsTo be flexible means to have the ability to vary as you like, according to the needs. Flexibility is the ability to adapt, in a reversible manner, to an existing situation, as opposed to evolution, which is irreversible. This notion reflects the ability to stay operational in changing conditions, whether they are predictable or not, completely different or not from conditions known in advance. This adaptability is required from firms that, for economic reasons, are currently turning to efficient techniques of organization and management of the zero stock, just-in-time and tight-flow type which can make them fragile. Competition amplifies the development of the market by creating new situations. This aspect, combined with the above mentioned techniques of organization, reduces the stability of the firm. The impact of an unexpected eventimmediately spreads across the structure because of the increased tension in the coordination links.Companies used to operate in the context of a market that was prepared – because of the scarcity of the available goods – to absorb all proposed products and services provided if they were consistent enough with demand .In such a situation the existence of inventories is an essential factor that guarantees uninterrupted operation. Building up stock is justified by the certainty of being able to sell it.The current economic context leaves the conflict of scarcity more and more behind us, thus removing the certainty of selling; on the contrary, protection by means of stock becomes a danger in itself. Calling production for stock into question has thus led to just-in-time production.This kind of operation makes the production system more vulnerable.As the classic organization of production, even though it is effective, high costs of operation are generated under these circumstances. It became necessary to create a new, efficient organization, complex to install, but capable of adapting itself continuously while, at the same time, optimizing the time required and the cost of change. This is how the flexible organization was born.Flexibility in supply chains may well represent a potential source to improve the company's efficiency and may be a significant measure of supply chain performance .ReferencesAngel Martínez Sánchez, Manuela Pérez Pérez. 2005. ”Supply chain flexibility and firm performance”, International Journal of Operations & Production Management, Volume 25 Number 7.Angel Martínez Sánchez, Manuela Pérez Pérez, Rhonda R. Lummus. 2003. Industrial Management & Data Systems, Volume 103, Number 6.Barad, M., Sapir, D. 2003. "Flexibility in logistic systems-modeling and performance evaluation", International Journal of Production Economics, Vol. 85, No.3.Jones, R., Ostroy, J. 1984, "Flexibility and uncertainty", Review of Economic Studies, Vol. 51.Kickert, W.J. 1985, "The magic world of flexibility", International Studies of Management and Organization, Vol. 14 No.4.Vickery, S., Calantone, R., Droge, C. 1999, "Supply chain flexibility: an empirical study", The Journal of Supply Chain Management,Vol. 35, No.3.Vokurka, R.J., O’Leary-Kelly, S. 2000, "A conceptual model of supply chain flexibility”, Journal of Operations Management , Vol. 1103 Number 6.。
浅谈供应链风险管理
浅谈供应链风险管理学生姓名：学号：学院：专业：指导教师：论文成绩：摘要供应链网络结构的错综复杂性、外部环境的不确定性和供应链管理者过于追求精益化等原因,使得供应链具有较高的风险,供应链越来越容易遭受各类风险的影响。
供应链系统能够提供的潜在收益是巨大的,不可以被忽略。
然而,随着管理层不断地为其系统“瘦身”以追求更快的反应能力和更低的成本,这一系统正在变得越来越“脆弱”,企业对风险和不确定性的影响变得更为敏感。
一旦风险确实发生,往往会给供应链造成不可逆转的影响和巨大的损失,甚至会导致供应链的彻底断裂。
对供应链风险进行有效管理与控制能够使供应链更富有弹性,从而对各类风险具有更强的抵抗力,使供应链能够避免或者减少由于风险带来的损失。
良好的风险协调管理还能提高供应链的运作效率,降低供应链的成本,促进企业的持续发展。
因此,为了保证供应链的稳定和正常运行，企业必须针对供应链运作的环境、成员之间的合作关系等，分析和找出可能存在的任何风险，并对各种风险及其特征及时进行分析，采取不同的防范策略，保证供应链运行状况时刻处于被有效的监控状态，防止风险的发生。
针对潜伏的风险制定相应的应对措施，一旦有灾难发生，尽量是损失限制在最小范围内，故而，对供应链风险管理的研究具有重要的实际意义。
ABSTRACTSupply chain network structure of the complex, external environment and the uncertainty of the supply chain management is the pursuit of the lean wait for a reason, makes the supply chain has the high risk of the supply chain, the more and more vulnerable to the effects of all kinds of risks. The supply chain system can provide the potential gains is great, can not be ignored. However, as the management constantly as its system \"thin body\" to pursue a faster response ability and lower cost, this system is becoming more and more \"fragile\", the enterprise to the risk and uncertainty influence become more sensitive. Once the risk does happen, often to the supply chain cause irreversible influence and huge losses, and even cause the supply chain thoroughly fracture. Supply chain risk to carry out the effective management and control of supply chain can makemore elastic, thus to each kind of risk is of stronger resistance, make the supply chain can avoid or reduce the losses caused by the risks. Good coordinated risk management can improve the supply chain operating efficiency, reduce the cost of supply chain, and to promote the sustainable development of the enterprise. Therefore, in order to guarantee the stability of the supply chain and normal operation, the enterprise must according to the supply chain operation environment, the relationship between the members, analysis and find out the possible existence of any risk, and kinds of the risk and its characteristics were analyzed in time, and take different preventive strategy, guarantee the supply chain operation status moment in effective monitoring state, prevent the happening of the risk. According to the latent risk formulate corresponding measures, in case of a disaster, as far as possible loss is limited in a small range, so, the supply chain risk management research has important practical significance.关键词：供应链供应链管理供应链管理的风险供应链管理的风险应对策略目录一、文献综述..........................................二、问题的提出........................................三、什么是供应链管理..................................四、供应链风险的定义..................................五、供应链风险产生的原因..............................（一）供应链内生风险...............................（二）供应链外来风险...............................六、供应链风险管理的程序..............................七、关于供应链风险识别................................八、关于供应链风险估计与评价..........................九、供应链风险的应对策略..............................（一）柔性化的防范策略.............................（二）与供应链成员建立战略合作关系.................（三）加强对供应链企业的激励.......................（四）制定多发时间应急预案.........................（五）防范信息风险.................................（六）采用外包策略分散风险.........................（七）加强供应链文化建设，打造共同的价值观.........（八）加强采购管理，优化物流配送...................（九）供应商早期参与...............................（十）加强日常风险管理............................. 参考文献 ............................................. 致谢..............................................一、文献综述供应链是从产品生产资料商、加工商、分销商、零售商和消费者组成的自上而下的供销网络（许福才、蒙少东，2010）。
原材料供应商稳定情况范文
原材料供应商稳定情况范文【中英文实用版】English:The stability of raw material suppliers is crucial for any manufacturing company.A reliable supplier ensures a consistent supply of high-quality materials, which is essential for maintaining production and meeting customer demands.中文：原材料供应商的稳定性对于任何制造公司都至关重要。
一个可靠的供应商可以保证高质量材料的持续供应，这对于维持生产和满足客户需求至关重要。
English:However, supplier stability can be threatened by various factors such as financial difficulties, supply chain disruptions, or changes in the political and economic environment.It is important for companies to monitor these factors and take proactive measures to mitigate potential risks.中文：然而，供应商稳定性可能受到各种因素的威胁，如财务困难、供应链中断或政治和经济环境的变化。
公司需要监测这些因素，并采取主动措施减轻潜在风险。
English:One way to ensure supplier stability is to establish long-term relationships with reliable suppliers.This can be achieved by fosteringgood communication, providing incentives for loyalty, and maintaining open and honest dialogue.中文：确保供应商稳定性的方法之一是与可靠的供应商建立长期关系。
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Stability in Supply Chain NetworksBy Michael Ostrovsky∗August15,2007AbstractThis paper studies matching in vertical networks,generalizing the theory of matching in two-sided markets.It gives sufficient conditions for the existence of stable networks and presentsan algorithm forfinding two of them.One is the best stable network for the agents on the“upstream”end of an industry.The other is best for the agents on the“downstream”end.Thepaper describes several properties of the set of stable networks and discusses applications ofthe theory to the design of matching markets with more than two types of agents and to theempirical analysis of supply chains.(JEL C78,D40)∗Graduate School of Business,Stanford University,Stanford,CA94305(e-mail:ostrovsky@).I am especially grateful to Al Roth,Ariel Pakes,Drew Fudenberg,Parag Pathak,and Michael Schwarz for valuable advice and discussions during the early stages of this project.I also thank Attila Ambrus,John Asker,Jeremy Bulow, Jerry Green,Kate Ho,Paul Milgrom,Markus Mobius,John Roberts,Tayfun S¨o nmez,Bob Wilson,Pai-Ling Yin, co-editor,and anonymous referees for helpful comments and suggestions.The woollen coat,for example,which covers the day-labourer,as coarse and rough asit may appear,is the produce of the joint labour of a great multitude of workmen.Theshepherd,the sorter of the wool,the wool-comber or carder,the dyer,the scribbler,the spinner,the weaver,the fuller,the dresser,with many others,must all join theirdifferent arts in order to complete even this homely production.Adam Smith(1776)Following the work of David Gale and Lloyd S.Shapley(1962),matching in two-sided markets has been an active area of research in economics.It produced a number of successful practical applications as well as a variety of important theoretical results on the structure of matching markets and the close links between matching and other areas of economics,such as auction theory and competitive equilibrium theory.This stream of research focuses on markets with two sides: e.g.,the marriage market between men and women,the admissions market between colleges and students,or the labor market betweenfirms and workers.Such a market is typically viewed in isolation and interactions with other markets are ignored.In many situations,however,markets can be closely interconnected,and an agent’s behavior in one of them may be directly linked to his behavior and options in another.The preferences of a consultingfirm hiring college graduates depend on the number and types of its clients.The menu that a restaurant offers to its customers depends on the availability and prices of inputs from its suppliers.The amount of iron ore that a steel manufacturer wants to buy depends on the amount of steel it plans to sell.Interconnected markets can often be handled by the standard competitive equilibrium approach. That approach,however,is ill-suited for incorporating the discreteness and the high degree of heterogeneity of qualities,preferences,and contracts inherent in many settings.For example,on a macro level,we can talk about the average wage of management consultants and derive predictions about its movements in response to various shocks in the economy.Once,however,we look at that labor market more closely,it becomes clear that contracts are unique and personalized,assigning a specific worker to a specificfirm,location,and position at a specific wage.These features are easier to incorporate in a matching framework.The same is true about the restaurant market,the markets for iron ore and steel,and other differentiated markets.Section V talks about several such markets in more detail.This paper generalizes the results and techniques of two-sided matching literature to a particular kind of setting with interconnected markets:supply chain networks.The basic structure of this setting is as follows.An industry includes a number of agents:workers,producers,distributors, retailers,and so on.Some agents supply basic inputs for the industry and do not consume any of the outputs(e.g.,wheat farmers are the suppliers of basic inputs in a“farmer→miller→baker→retailer”supply chain).Some agents purchase thefinal outputs of the industry(e.g.,car manufacturers are the consumers offinal goods in an“iron ore supplier→steel producer→steel consumer”supply chain).The rest are intermediaries,who get their inputs from some agents in the industry,convert them into outputs at a cost,and sell the outputs to some other agents(e.g., millers,bakers,and steel producers are intermediate agents in the above examples).A key assumption in the two-sided matching literature is that the side to which a particular agent belongs does not depend on market conditions:a man cannot become a woman and a student cannot become a college.Likewise,I assume that the positions of agents in a supply chain are exogenouslyfixed.Specifically,there is a pre-determined upstream-downstream partial ordering on the set of agents:for a pair of agents A and B,either A is a potential direct or indirect supplier for B,orB is a potential direct or indirect supplier for A,but not both;it may also be the case that neither is a potential supplier for the other.This ordering can be very simple,with several “tiers”offirms,each of whom buys its inputs fromfirms in the previous tier and sells its outputs tofirms in the next tier.It can also be more complicated,with several alternative technologies, several paths of different lengths connecting the suppliers of basic inputs to the consumers offinal outputs,and withfirms being able to trade both directly and through intermediaries.However, it cannot have cycles:an agent cannot be a direct or an indirect supplier for one of its upstream nodes.Note that if there are no intermediate agents,this setting reduces to a two-sided market.Agents can trade discrete quantities of goods,with the smallest tradeable quantity(the unit of quantity)defined ex ante.For example,one unit may correspond to one million tons of steel, one hour of work,or one loaf of bread.In the Gale-Shapley two-sided marriage market,one unit corresponds to marriage,and each person can“trade”at most one unit.Following the literature on two-sided matching with wages and endogenous job characteristics(Vincent P.Crawford and Elsie M.Knoer,1981;Alexander S.Kelso and Crawford,1982;Alvin E.Roth,1984;John W.Hatfield and Paul Milgrom,2005),units traded in the market are represented by contracts.In my setting, each contract specifies the buyer,the seller,the price(if monetary transfers are involved),andthe serial number of the traded unit(if multiple units can be traded).A network is a set of contracts:it specifies who sells what to whom and at what price.Each agent has preferences over sets of contracts involving it: e.g.,an intermediate agent’s payofffrom such a set depends on the payments it makes for its inputs(specified in its upstream contracts)and receives for its outputs(specified in its downstream contracts),as well as on the cost of converting the inputs into the outputs.For a consumer offinal goods,the payoffdepends on the utility from the goods it purchases and the payments it makes for these goods.I say that a network is chain stable if there is no upstream-downstream sequence of agents(not necessarily going all the way to the suppliers of basic inputs and the consumers offinal outputs)who could become better offby forming new contracts among themselves and possibly dropping some of their current contracts.This condition is parallel to pairwise stability in two-sided markets, and is tautologically equivalent to it if there are no intermediate agents in the industry.Note that the concept of stability in networks is not strategic—I do not study the dynamics of network formation or“what-if”scenarios analyzed by agents who may be considering temporarily dropping or adding contracts in the hopes of affecting the entire network in a way beneficial to them,although these considerations are undoubtedly important in many settings.The concept is closer in spirit to general equilibrium models,where agents perceive conditions surrounding them as given,and optimize given those conditions.Under chain stability,agents also perceive conditions surrounding them as given(i.e.,which other agents are willing to form contracts with them,and what those contracts are),and optimize given these conditions.Without restrictions on preferences,the set of stable matchings may be empty even in the two-sided one-to-many setting.A commonly used restriction that is sufficient to guarantee the existence of stable matchings in that setting is the gross substitutes condition of Kelso and Crawford(1982). In the supply chain setting,I place an analogous pair of restrictions on preferences;these restrictions become tautologically equivalent to the substitutes condition if there are no intermediate agents in the industry.The restrictions are same-side substitutability and cross-side complementarity.Same-side substitutability is a direct generalization of the gross substitutes condition.It says that when the set of available downstream contracts of afirm expands(i.e.,there are more poten-tial customers,or the potential customers’willingness to pay goes up),while the set of available upstream contracts remains unchanged,the set of downstream contracts that thefirm rejects also (weakly)expands.Symmetrically,when the set of available upstream contracts expands and theset of available downstream contracts remains unchanged,the set of rejected upstream contracts also expands.Cross-side complementarity is a new restriction,which specifies how afirm’s purchasing and selling decisions are interrelated and thus links the markets along the supply chain.This restriction can be viewed as a mirror image of same-side substitutability.It says that when the set of available downstream contracts of afirm expands,while the set of available upstream contracts remains unchanged,the set of upstream contracts that thefirm forms also weakly expands.Symmetrically, when the set of available upstream contracts expands and the set of available downstream contracts remains unchanged,the set of downstream contracts that thefirm forms also weakly expands.The restrictions of same-side substitutability and cross-side complementarity are natural and flexible;however,there are several important types of preferences and production technologies that they rule out.I discuss these restrictions in more detail in Section I.A.The main result of the paper states that under same-side substitutability and cross-side com-plementarity,there exists at least one chain-stable network.The proof is constructive:it presents an algorithm forfinding such a network.This algorithm is a generalization of thefixed-point algo-rithms of Hiroyuki Adachi(2000),Federico Echenique and Jorge Oviedo(2004,2006),and Hatfield and Milgrom(2005),which are in turn generalizations of the Deferred Acceptance Algorithm of Gale and Shapley(1962)and the Salary Adjustment Process of Crawford and Knoer(1981)and are applicable only to two-sided markets.The set of chain-stable networks has some interesting properties.The chain-stable network formed in the constructive proof of the existence theorem is upstream-optimal:it is the most preferred chain-stable network for all suppliers of basic inputs and the least preferred chain-stable network for all consumers offinal outputs.A slightly modified algorithm produces the downstream-optimal chain-stable network.The existence of these side-optimal networks is a generalization of the classic result in the theory of two-sided matching,which says that the Deferred Acceptance Algorithm converges to the man-optimal stable matching(Gale and Shapley,1962).Another property of the set of stable matchings in two-sided markets is that adding agents on one side of the market makes other agents on that side of the market weakly worse offand makes the agents on the other side weakly better off,in the two side-optimal stable matchings(Kelso and Crawford,1982; Gale and Marilda Sotomayor,1985).This result can also be extended to the supply chain setting: Adding a new supplier of basic inputs to the industry makes other such suppliers weakly worse offand makes the consumers offinal outputs weakly better offat both upstream-and downstream-optimal chain-stable networks.Symmetrically,adding a new consumer offinal outputs makes other such consumers worse offand makes the suppliers of basic inputs better off.These results are very different from the conclusions of several other papers that discuss gen-eralizations and extensions of two-sided matching,but do not impose the supply chain structure of this paper.Gale and Shapley(1962)show by example that the“problem of the roommates,”whose only difference from the“marriage problem”is the absence of two sides in the market,may fail to have a stable pairing.Ahmet Alkan(1988)shows that the“man–woman–child marriage problem,”in which each match consists of agents of three different types,may also fail to have a stable matching.Hernan Abeledo and Garth Isaak(1991)prove that to guarantee the existence of stable pairings under arbitrary preferences,it has to be the case that each agent belongs to one of two classes,and an agent in one class can match only with agents in the other class.Note that there is no contradiction between my results and the result of Abeledo and Isaak:in their setting, matching is one-to-one,and so for a particular agent,all acceptable matches are substitutes for one another.In contrast,in the setting of this paper some agents are intermediaries whose prefer-ences satisfy cross-side complementarity and who therefore do not view all acceptable matches as substitutes.Finally,Hideo Konishi and M.Utku¨Unver(2006,Theorem3)show that in general multi-partner matching problems with bilateral links and responsive preferences,several different solution concepts are equivalent to pairwise stability.In their setting,however,the set of stable matchings may be empty.To guarantee the existence of chain-stable networks,I assume that agents’preferences satisfy the cross-side complementarity and same-side substitutability conditions.A similar restriction on preferences was independently introduced by Ning Sun and Zaifu Yang(2006)in the context of exchange economies with two types of heterogeneous indivisible objects,quasi-linear preferences, and continuous prices.From the point of view of each agent,objects of one type are substitutes, while objects of different types are complements.For example,from the point of view of a manufac-turingfirm,workers and machines are complements,while all workers are substitutes for each other and all machines are also substitutes.Sun and Yang(2006)show that in this model a competitive equilibrium always exists.I discuss the connection between this result and the results of the current paper in Section V.C.The rest of this paper is organized as follows.Section I formally introduces the model ofmatching in supply chains.Section II presents the constructive proof of the main result of the paper:under same-side substitutability and cross-side complementarity,chain-stable networks are guaranteed to exist.Section III studies the properties of the set of chain-stable networks.Section IV discusses chain stability and alternative solution concepts.Section V talks about applications and extensions of the model.Section VI concludes.I.The Model of Matching in Supply ChainsConsider an industry,consisting of afinite set A of nodes(firms,countries,agents,workers,and so on).An exogenously given“upstream–downstream”partial ordering“ ”on this set determines possible trading relationships:a b stands for b being a downstream node for a and means that a can potentially sell something to b.If a b and b a,then there can be no relationship between a and b.By transitivity,there are no loops in the market.Relationships between pairs of nodes are represented by bilateral“contracts.”Each contract c represents one unit of a good sold by one node to another.It is a vector,c=(s,b,l,p),where s∈A and b∈A are the“seller”and the“buyer”involved in the contract,s b;l∈N is the “serial number”of the unit of the good represented by the contract;and p∈R is the price that the buyer pays to the seller for that unit.The seller involved in contract c is denoted by s c,the buyer is denoted by b c,and so on.Multiple contracts between a seller and a buyer can represent multiple units of the same good or service,units of different types of goods or services,or both.For instance,if the unit is one ton,and a farmer sells5tons of wheat and10tons of rye to a miller,then this relationship will be represented by15contracts with15different serial numbers.The example in Appendix B illustrates the use of serial numbers.The set of possible contracts,C,isfinite and is also given exogenously.In the simplest case,it can include all possible contracts between nodes in A,with all possible serial numbers from some finite set,and all possible prices from somefinite set.It can also be more complicated: e.g.,the U.S.trade embargo on Cuba can be incorporated simply by removing all contracts between the nodes in these countries from set C.Note that this framework,restricted to one“tier”of sellers and one“tier”of buyers,encompasses various two-sided matching settings considered in the literature.Setting l≡constant and p≡0 turns this model into the marriage model of Gale and Shapley(1962),assuming that each agentis allowed to have at most one partner.Setting l≡constant turns it into the setup of Kelso and Crawford(1982),assuming that agents on one side are restricted to having at most one link,and into the many-to-many matching model of Roth(1984,1985)and Charles Blair(1988),assuming that agents on both sides are allowed to have multiple links.Setting p≡0and assuming that all links connecting two nodes are identical turns the model into a discrete version of the schedule matching problem of Mourad Ba¨ıou and Michel Balinski(2002)and Alkan and Gale(2003).A.PreferencesEach node can be involved in several contracts,some as a seller,some as a buyer,but it cannot be involved in two contracts that differ only in price p,i.e.,it cannot buy or sell the same unit twice.Nodes have preferences over sets of contracts that involve them as the buyer or the seller. For example,in the simplest case of quasi-linear utilities and profits,the utility of node a involved in a set of contracts X isV a(X)=W a({(s c,b c,l c)|c∈X})+c∈D p c−c∈Up c,where D={c∈X|a=s c}and U={c∈X|a=b c},i.e.,D is the set of contracts in X in which a is involved as a seller and U is the set of contracts in which a is involved as a buyer.W a(·) represents the utility from the purchased contracts for the consumers at the downstream end of the chain,the cost of producing the sold contracts for the suppliers at the upstream end of the chain, and the cost of converting inputs into outputs for the intermediate nodes.For an agent a∈A and a set of contracts X,let Ch a(X)be a’s most preferred(possibly empty)subset of X,let U a(X)be the set of contracts in X in which a is the buyer(i.e.,upstream contracts),and let D a(X)be the set of contracts in X in which a is the seller(i.e.,downstream contracts).Subscript a will be omitted when it is clear from the context which agent’s preferences are being considered.Preferences are strict,i.e.,function Ch a(X)is single-valued.In the settings in which it is natural to assume that several different sets of contracts should result in identical payoffs(e.g.,when two nodes can trade several identical units of a good),I assume that ties are broken in a consistent manner;e.g.,lexicographically:in the case of several identical units of a good,that would imply that seller a prefers contract(a,b,1,p)to contract(a,b,2,p),but would prefer(a,b,2,p )to(a,b,1,p)for any p >p.Preferences of agent a are same-side substitutable if for any two sets of contracts X and Y such that D(X)=D(Y)and U(X)⊂U(Y),U(X)\U(Ch(X))⊂U(Y)\U(Ch(Y))and for any two sets X and Y such that U(X)=U(Y)and D(X)⊂D(Y),D(X)\D(Ch(X))⊂D(Y)\D(Ch(Y)). That is,preferences are same-side substitutable if,choosing from a bigger set of contracts on one side,the agent does not accept any contracts on that side that he rejected when he was choosing from the smaller set.Preferences of agent a are cross-side complementary if for any two sets of contracts X and Y such that D(X)=D(Y)and U(X)⊂U(Y),D(Ch(X))⊂D(Ch(Y))and for any two sets X and Y such that D(X)⊂D(Y)and U(X)=U(Y),U(Ch(X))⊂U(Ch(Y)).That is,preferences are cross-side complementary if,when presented with a bigger set of contracts on one side,an agent does not reject any contract on the other side that he accepted before.Same-side substitutability is a generalization of the gross substitutes condition introduced by Kelso and Crawford(1982)and used widely in the matching literature.If there are only two sides in the supply chain market,then these two conditions become tautologically equivalent.Cross-side complementarity is a new restriction,which is automatically satisfied in any two-sided market.In a supply chain setting,it is this restriction that“ties together”the purchasing and selling decisions of a node and thus links the markets along the supply chain.It can be viewed as a mirror image of same-side substitutability:when the set of potential contracts on the node’s one side expands, same-side substitutability says that the set of rejected contracts on that side also expands,while cross-side complementarity says that the set of accepted contracts on the other side expands.It is important to highlight what is allowed and what is not allowed by this pair of assumptions. Two possibilities that they rule out are scale economies and production functions withfixed costs, because in those cases afirm may decide not to produce one unit of a good at a certain price, while being willing to produce ten units at the same price,violating same-side substitutability. Complementary inputs(or outputs)are also generally ruled out.1Another possibility that is ruled out is an intermediary withfixed capacity(say,1unit)who can transform an input of type A into an output of type A or an input of type B into an output of type B,but not both(due to the capacity constraint).An addition of a cheap type-A input to this intermediary’s set of options may cause him to shift from buying one type-B input and selling one type-B output to buying one type-A input and selling one type-A output,thus violating cross-side complementarity.1See,however,the discussion in Section V.C.In contrast,with substitutable inputs and outputs and decreasing returns to scale,many pro-duction and utility functions can be accommodated.The simplest example is afirm that can take one kind of input and produce one kind of output at a cost,with the marginal cost of production increasing or staying constant in quantity.The input good can come from several different nodes, and the output good may go to several different nodes,with different transportation costs.Much more general cases are possible as well:preferences and production functions with quotas and tar-iffs,several different inputs and outputs with discrete choice demands and production functions, capacity constraints and increasing transportation costs,etc.The interdependencies between different inputs or outputs can be rather complex as well.Con-sider the following example.Afirm has two plants in the same location.Each plant’s capacity is equal to one unit.Thefirst plant can convert one unit of iron ore into one unit of steel for q1o or it can convert one unit of steel scrap into one unit of steel for q1s.The second plant can convert one unit of iron ore into one unit of steel for q2o or it can convert one unit of steel scrap into one unit of steel for q2s.Then,for a generic choice of costs and prices,the preferences of thisfirm will be same-side substitutable and cross-side complementary,even though thefirm’s preferences over iron ore and scrap are not trivial(they cannot be expressed by simply saying that two alternative inputs are perfect substitutes,with one being better than the other by a certain amount x).This example is an analogue of“endowed assignment valuations”in two-sided matching markets (Shapley,1962;Hatfield and Milgrom,2005),in which eachfirm has several unit-capacity jobs,each worker has a certain productivity at each job,and eachfirm has an initial endowment of workers. Even in the two-sided setting,it is an open question whether endowed assignment valuations exhaust the set of utility functions with substitutable preferences,and so it is an open question in the supply chain setting as well.For the remainder of this paper,all preferences are assumed to be same-side substitutable and cross-side complementary,and these restrictions will often be omitted from the statements of results to avoid repetition.B.Stable NetworksIn the model,relationships between the nodes are represented by contracts.I call a collection of relationships between the nodes in a market a network,i.e.,a network is simply a set of contracts. Letµ(a)denote the set of contracts involving a in networkµ.Networkµis individually rationalif it does not contain any two contracts differing only in price(afirm cannot sell the same good twice)and for any agent a,Ch a(µ(a))=µ(a),i.e.,no agent would like to unilaterally drop any of his contracts.The most widely used solution concept in the two-sided matching literature is pairwise stability. Its analogue in the supply chain setting is chain stability,defined as follows.A chain is a sequenceof contracts,{c1,...,c n},n≥1,such that for any i<n,b ci =s ci+1,i.e.,the buyer in contractc i is the same node as the seller in contract c i+1.Note that the chain does not have to go all theway from one of the most upstream nodes in the market to one of the most downstream nodes;it can connect several nodes in the middle of the market.For notational convenience,let b i≡b ciands i≡s ci.For a networkµ,a chain block is a chain{c1,...,c n}such that•∀i≤n,c i/∈µ,•c1∈Ch s1(µ(s1)∪c1),•c n∈Ch bn(µ(b n)∪c n),and•∀i<n,{c i,c i+1}⊂Ch bi=s i+1(µ(b i)∪c i∪c i+1).In other words,a chain block of networkµis a downstream sequence of contracts not belonging to µ,in which the buyer in one contract is the seller in the next one,such that each node involved in these contracts is willing to add all of its contracts in the sequence to its contracts inµ,possibly dropping some of its contracts inµ.A network is chain stable if it is individually rational and has no chain blocks.Note that chain stability is not a strategic concept—each node views the set of contracts available to it as exogenously given,and maximizes its payoffgiven that set,analogously to how consumers in the Walrasian equilibrium setting choose quantities taking prices as given.Hence,each node treats its contracts independently of one another,ignoring the effect of forming one contract on other nodes’willingness to pay for other contracts.For example,if there are only two nodes in the market, the seller(whose marginal cost is increasing in quantity)and the buyer(whose marginal benefit is decreasing in quantity),who can trade multiple units of a good,then chain stability implies that the quantity traded between those two nodes is determined by the intersection of the agents’marginal cost and marginal benefit curves.In more general networks,nodes also ignore various sorts of externalities they may impose on others(e.g.,limiting the supply of inputs available to competitorsby buying too much and thus reducing the competition in the market for outputs).Hence,the model is not directly applicable to cases in which there are several large players manipulating the market;it is better suited to describing competitive markets with many small players,or markets in which nodes represent countries or regions rather thanfirms.C.An ExampleI now turn to an example that illustrates the definitions introduced above.It consists of two simple two-sided matching markets“stacked”on top of each other.The markets are tied together by the restriction on the preferences of intermediate agents,who need to have a supplier in order to be able to supply a customer.For simplicity,there are no prices or unit identifiers in this example.Another example,presented in Appendix B,incorporates prices,unit identifiers,and more complicated trade patterns,allowing the suppliers of basic inputs and the consumers offinal outputs to trade both directly and trough intermediaries.Example1:There are six agents in the market:two suppliers of basic inputs(a1,a2),two intermediaries(b1,b2),and two consumers offinal outputs(c1,c2).For all i,j,and k,a i b j c k.Suppliers cannot trade directly with consumers:tradeflows have to go through intermediaries. All agents have unit capacities:each supplier can supply one unit of the good;each consumer needs one unit;each intermediary can process one unit.There are no prices or quantities in this market. The set C of available contracts consists of eight elements:C={(a1,b1),(a1,b2),(a2,b1),(a2,b2), (b1,c1),(b1,c2),(b2,c1),(b2,c2)}.Prices and unit identifiers were dropped from the contracts since they play no role in this example.Each supplier is willing to sell to any intermediary and prefers to sell to the intermediary with the same index as his own rather than to the intermediary with the other index.Hence,the most preferred set of contracts for supplier a1is{(a1,b1)},the second most preferred is{(a1,b2)},and the third is the empty set.Similarly,a2prefers{(a2,b2)}to{(a2,b1)},which he in turn prefers to the empty set.Each consumer is willing to buy from any intermediary and prefers to buy from the intermediary with a different index rather than from the intermediary with the same index as her own.Hence,the most preferred set of contracts for consumer c1is{(b2,c1)},the second most preferred is{(b1,c1)}, and the third is the empty set.Similarly,c2prefers{(b1,c2)}to{(b2,c2)},which she in turn prefers to the empty set.。