Research paper范文：The effect of location decision on a business success
Research Paper代写范例-选址决策对企业成功的影响。本文是一篇本站提供的research paper代写参考范文，主要内容是讲述当今竞争激烈的市场要求公司尽可能有效地提供产品和服务。分销策略是成功的关键。分销网络的关键组成部分之一是仓库位置。选址决策被认为是一项长期的商业战略决策。正确的选址决策可以显著改善业务流程和性能，并带来相对于竞争对手的竞争优势（即成本节约、服务质量等）。另一方面，如果做出了一个糟糕的选址决定，公司同样会付出时间、金钱和机会。位置决策的环境是动态的，通常被描述为多标准决策。下面就一起来看一下这篇research paper代写范例的具体内容。
The effect of location decision on a business success
2.1 Introduction
Todays competitive market demands companies to deliver their products and services as effectively and efficiently as possible. The distribution strategy is the key to the success. One of the key components of a distribution network is warehouse location. Location decision is considered as a long-term business strategic decision. The correct location decision can resulted in significant improvement in business processes and performance, and bring competitive advantages (i.e. cost saving, service quality, etc.) over its competitors. On the other hand, if a poor location decision was made, it could equally cost the company time, money and opportunity. The location decision’s environment is dynamic and normally described as a multi-criteria decision.
Furthermore, the globalisation and the rapid evolution of information technology have changed the characteristics of location problems. There are two major trends in facility location selection accordingly to Yang and Lee (1997). First, there has been an increased interest to gain potential competitive edge in the global marketplace. Second, small to medium-sizes communities has become more attractive to many businesses as new facility location. These two trends are influenced by the more advanced communication technology, better transportation infrastructure system, liberalised trade between countries, and so on. This allows company to select their facilities where they think has the most advantages (i.e. in land cost, labour cost, skilled labour availability, etc.).
This chapter will start by identifying why a company needs to improve its logistics system, then defining the linkage between the organisation’s strategy and the logistics strategy, followed by the general roles of warehouse in distribution strategy. Then it will present the influencing location factors companies normally consider when they make location decisions. And finally in the latter section of this chapter, it will present literature reviews of decision aid techniques and model used in location decisions.
2.2 Logistics system and the changing business environment
Why do we need to change our logistics operations and strategy? The main reason why we need to change is because the environment we live in is constantly and rapidly changing. In order to survive in this unforgiving environment businesses are forced need to change. There are many factors given by Rushton, et al. (2006) including increasing customer demand, reducing product life cycle, changing technologies, increasing pressures from competitors, and so on. The pressures for change given by Rushton, et al. (2006) are illustrated by the figure 1.
Figure 1 Pressure influencing logistics systems
2.3 Logistics strategy
Logistics strategy should aim to establish the most appropriate blend of storage and transport at a given customer service level. Efficient logistics and distribution strategies should reduce the total logistics costs and must take into account the interactions of various the various replenishment activities in the distribution chain (Rushton, et al., 2006; Teo & Shu, 2004).
Chopra and Meindl (2004) suggest there are four drivers to a successful distribution system: (1) Facilities – location, capacity, operations methodology, and warehousing methodology; (2) Inventory – cycle inventory, safety inventory, seasonal inventory, and sourcing; (3) Transportation – mode of transportation, route and network design, and in-house or outsource decision; and (4) Information – push or pull, coordination and information sharing, forecasting and aggregate planning, and enabling technologies. Bowersox and Closs (1996) suggest similar points but they also add another driver which is ‘network design’. They also claim that classical economics often neglected the importance of facility location and overall network design. Similarly but in more details, Alling and Tyndall (1994) identify ten principles that make logistics operations successful. They are: (1) to link logistics to corporate strategy; (2) to organise logistics comprehensively; (3) to use the power of information technology; (4) to emphasize human resources – recognising the importance of quality human resources; (5) to form strategic alliances; (6) to focus on financial performance; (7) to target optimum service levels; (8) to manage the details – pay attention to details as it can be significant savings; (9) to leveraging logistics volume – through consolidating shipment volumes, inventories and the like; and (10) to measure and react to performance.
Furthermore, when considering a distribution strategy, warehousing strategy is an important part and typically the decision makers or logistics planners has to answer these questions (1) should warehousing facilities be owned, leased or rented, (2) what is the optimal size and number of warehouses, (3) what are the optimal locations for warehouses, (4) what product line should be stocked at each warehouse location, and what market areas should be serviced from each warehouse location. (Stock & Lambert, 2001; Bowersox & Closs, 1996; Simchi-Levi, et al., 2003; Bowersox & Closs, 1996; Geoffrion & Powers, 1995; Bender, 1994; Stock & Lambert, 2001; Greasley, 2009)
Matching logistics strategy to business strategy
The important key to achieving the strategic fit is the ability of the company to find a balance between responsiveness and efficiency that best matches the business strategy. Whatever strategies chose to implement by the company, there will be impacts. And the impact of the selected logistics and distribution strategy has to be assessed against the business strategy. Often these may involve undertaking some qualitative analysis where it is impossible to derive good quantitative measures. The main areas of where this will impact, they are (Rushton, et al., 2006): a) Capital costs – this is the costs of new facilities, new equipments, and so on. In certain situations capital constraints can exclude otherwise attractive options; b) Operating costs – the minimum operating cost is often the main criterion for selection between options. In some cases increased operating costs can be accepted in the light of future flexibility; c) Customer service – Although options should have been developed against customer service targets, the selected short list must be examined for the customer service level achieved. The balance of the mix might have changed in an effort to reduce costs. Stock held close to the customer might need to be increased to improve service reliability.
2.5 Obstacles to achieving strategic Fit
As many as there are many factors and influences to achieving the strategic fit in the supply chain, there are also many obstacles to achieving the same goal as Chopra and Meindl (2004) and few other writers mention. Few examples of the obstacles to strategic fit are: a) the variety of products – the increasing variety of products tends to raise uncertainty and uncertainty tends to raise costs and reduce responsiveness within the system; b) the product lifecycles – the decreasing product lifecycles also tends to raise uncertainty and reduce the window of opportunity to achieving strategic fit; c) the increasingly demanding customer – customers demand for faster fulfilment, better quality, and better value for money for the product they buy, companies must be able to provide these just to maintain their businesses; d) the fragmentation of supply chain ownership – less vertically integrated structure can result in difficult coordination to achieving strategic fit; e) the effect of globalization – difficulties raised by the invasion of foreign players. It is noticed that these factors are the same factors which drives the need to improve logistics system as determined in section 2.2.
2.6 The logistics and distribution planning framework
Many authors agree on the first and the most important step, when planning the logistics and distribution, which is to identify the objective and strategies of the organization. Then it follows by the second step which is to gain a detailed understanding of the present position of the system. The rests of the procedures are identifying the options, analysing the options, comparing and evaluating the results, and developing a planning and implementation. A diagram illustrating the approach to distribution planning by Rushton, et al. (2006) is shown in the figure 3 below.
Figure 2: An approach to logistics and distribution planning (Rushton, et al., 2006)
2.7 Optimal number of warehouses
The optimal number of warehouses can be found by using a costing model, a model which takes into account of variable costs, particularly the transport and operating costs. Few facilities give low cost for inward transport, but high cost for outward transport, as they are, on average, further away from customers. On the other hand, more number of facilities can give higher cost for inward transport, but the cost for outward transport is lower, as they are, on average, closer to customers. Another cost that varies with the number of facility is the operating costs. Higher number of facilities means the company has to bear more expensive cost to operating these facilities. Operating costs also vary with facility size. Generally, larger facilities give the economies of scale; however, this is not always the case. Higher cost from operating larger facilities may come from the cost of supervision, communication, inefficiency and so on (Attwood & Attwood, 1992; Bowersox & Closs, 1996; Waters, 2003; Chopra & Meindl, 2004; Rushton, et al., 2006). Figure 4 graphically illustrates the relationships between number of facilities and costs incurred.
Figure 3 Relationship between costs and numbers of facilities.
The need to hold inventories
Prior to planning and designing logistics and distribution system, it is very important to be aware of the reason why a company need to hold stock. The most common objective of a supply chain is to efficiently balancing demand and supply. As most people understand that it is impossible to precisely synchronise or balance the requirements of demand with the fluctuations of supply. Therefore stocks are there to provide buffer between supply and demand. Rushton, et al. (2006) reviews the important reasons to stock, as follows: a) to keep down production costs – keeping production to run as long as possible, as the costs of setting up machine is often expensive; b) to accommodate variation in demand – to avoid stock-outs by holding some level of safety stock; c) to take account of variable supply (lead) times – to cover any delays of supplies from producers and suppliers; d) to reduce buying costs – often there are administrative cost of placing an order, holding additional inventory can reduce these costs; e) to take advantage of quantity discounts – often goods are offered at a cheaper cost per unit if they are ordered in large quantity; f) to account for seasonal fluctuations – certain products are popular in a certain time of the year, retailer normally pile-up inventory during low demand season to cater the demand in high season; g) to allow for price fluctuations/speculation – the price of certain products, steel for instance, fluctuate due to variety of reasons. Some companies buy in large quantity to cater this; h) to help the production and distribution operations run more smoothly – stock is held to ‘decouple’ two different activities; i) to provide customers with immediate service – stocks enables companies to provide goods and service as soon as they are required to maximise the sales opportunity. This is essential in highly competitive markets; j) to minimise production delays caused by lack of spare parts – Breakdowns of machineries required to produce goods or services can be very costly to business. Having spare parts to fix the machineries as soon as it breakdowns is an advantage; k) to facilitate the production process by providing semi-finished stocks between different processes (Work-in-Progress).
2.9 Roles of warehouse
Why businesses need warehouse? There are many reasons why business needs warehouses. Warehouse has many roles apart from providing storage and supplying the materials or finished goods to producers or retailers as reviewed in the previous section. In fact warehouse has many other roles and functionalities which can be classified on the basis of economics and service accordingly to Bowersox and Closs (1996). On the basis of economics, a warehouse is economically justified when the total logistical costs are reduced by providing the facility. On the basis of service, a warehouse is justified when the overall logistical system can provide a better service, in terms of time and place capability.
Here are some common roles of a warehouse (Bowersox & Closs, 1996; Higginson & Bookbinder, 2005; Rushton, et al., 2006):
Role as a make-bulk/break-bulk consolidation centre – making bulk and breaking bulk are traditional functions of a warehouse/DC. In a break-bulk facility, large incoming loads are aggregated, often for product mixing and to create consolidated out- bound shipments. A make-bulk facility, or consolidation centre, com- bines small quantities of several products in fewer, larger assortments.
Role as a cross-docking station – Cross-docking is a process where the product is received, occasionally combined with different products going out to the same destination, and then shipped at their earliest opportunity without being stored. Cross-docking has many benefits, including: faster product flow, no inventory pile-up, reduced product handling, and reduce cost due to elimination of those activities.
Role as a transhipment facility – transhipment refers to a process of taking a shipment out of one vehicle and loading it onto another. It only occurs when there is a good reason to change transportation modes or vehicle types.
Role as an assembly facility – Hewlett Packard’s distribution centre is a good example of the role as an assemble facility. It also benefits from the idea of postponement which allows product differentiation until later stages. Products are designed to use generic parts and assemble at the warehouse.
Role as a product-fulfilment centre – the major function is to find the products that are ordered and directly deliver them to the final customer. Amazon.com warehouse is a good example.
Role as depot for returned goods – the major functions are to inspect and separate the returned good into those that can be repaired, repackaged, resale, or recycled.
2.10 Transportation
Accordingly to Chopra and Meindl (2004), the target level of service the company sets determines the role of transportation in a company competitive strategy. If the company is targeting customers whose main criterion is price, then the company can use transportation to lower the cost of the product at the expense of reponsiveness. But more often companies tries to achieve the right balance between efficiency and responsiveness using both inventory and transportation.
Often in logistics plannings, decision to make to make any changes based on the costs of transportation. Accordingly to Rushton, et al. (2006), the transportation costs can be broken into three main types. The first one is the fixed costs – these costs must be borne whether the vehicles run for 10 or 100 kilometres and might include the depreciations of the vehicles, the licence fees, the insurance, etc. And these may vary from one vehicle to another depending on various reasons. The second type is the variable costs – these costs vary in relation to the activity of the vehicles, i.e. how far the vehicle travelled. The most obvious example of a variable of cost is the fuel cost. And the last type is the overhead costs – these costs are indirect costs that are borne by the whole fleet of vehicles. They may be the usual business overheads that are required to run the vehicles, i.e. staff salaries, telephone, internet, and other administrative expenses.
2.11 Location decision objectives
Warehouse site selection is a complex process involving multiple, both qualitative and quantitative, criteria. And often location decisions have more than one objective depending on the organisation’s objectives and strategies. Current, et al., (1990) classified the objectives for facility location problems into four general categories namely: (1) Cost minimisation; (2) Demand Oriented; (3) Profit maximisation; (4) Environment concern, and often these objectives are found to overlap each other. For retailing business, cost minimisation and profit maximisation are often the main objectives.
2.12 The influences of warehouse site location selection
It is important to effectively identify potential locations for the new warehouses. Typically, these locations must satisfy a variety of conditions and the potential locations should meet all the requirements. The potential locations should take into account the future demand and that the decision should have an impact on the firm for at least the next three to five years (Simchi-Levi, et al., 2003).
Many authors (Chase, et al., 2004; Barnes, 2008) suggested that the choice of facilities location is influenced by two principles. The first one is the need to locate close to customer due to time-based competition, trade agreement, and transportation cost. And the second one is the need to locate close to the access to resources such as labour, raw material, and specialist skills and capabilities. Often the two principles are taken into account when an organization makes a decision on the choice of location. The characteristics of operations of business (i.e. Manufacturer or service provider) will govern the weight of factors should be taken into account.
Barnes (2008) looked at the location decision on the international perspective where the influential facility location factors are more in numbers and level of complexity. However, these factors can be adapted and used for domestic facility location. Here is the list of major factors which in themselves comprises of several sub-factors given by Barnes (2008): Costs; Labour characteristics; Infrastructure; Proximity to suppliers; Proximity to market/customers; Proximity to parent company facilities; Proximity to competition; Quality of life; Legal and regulatory framework; Economic factors; Government and political factors; Social and cultural factors; and Characteristic of a specific location.
Bowersox and Closs (1996) concentrated on the warehouse location analysis in the context of logistical network strategy. He discusses about three warehouse location patterns namely Market-Positioned Warehouse, Manufacturing-Positional Warehouse, and Intermediately Positioned Warehouse. They imply the similar idea of the two principles suggested by Chase, et al. (2004) and Barnes (2008). They also discussed the warehouse location from the viewpoint of transportation economies and from the viewpoint of inventory economies. Furthermore they incorporate the concept of Least-Total-Cost system where the sum of total inventory cost and transportation cost is minimal to design the warehouse network.
The conditions or attributes of potential warehouse locations reviewed from many literatures are summarised as follows:
Site-related factors
Regional factors
Land cost/size/soil characteristics/ drainage
Proximity to market
Construction costs/leasing cost/renting costs
Proximity to suppliers
Transportation facilities/cost
Proximity to competitors
Zoning restrictions
Proximity to industry
Community factors
Geographical characteristics
Quality of life/cost of living
weather characteristics
Public facility accessibility
Labour cost/availability/skill
Taxes
Energy availability/cost
Environment regulation
Telecommunication facility
Local government support/incentives
Political matters and regulation
Sustainability
Transportation infrastructure
2.13 Methods and techniques in facility location problems
In this section, we will review the methods, techniques, and approaches found in a number of literatures.
Bowersox and Closs (1996) claim that a sophisticated modelling and analysis techniques are required in location decision because the location analysis is very complex and data-intense. The complexity is created because of the number of locations multiplied by the alternative location sites multiplied by the stocking strategies for each location. Meanwhile, the data intensity is caused by the requirement of detailed demand and transportation information. Furthermore, the facility site selection process is complicated by the impact of environment legislation and related political issues (Bowersox & Closs, 1996).
Thai and Grewal (2005) suggest the conceptual framework of location selection for distribution centre that consists of three main stages. The first stage is a general geographical area for distribution centre is identified based on the Centre-of-Gravity principle. The second stage is the identification of location alternatives of distribution centre and associate gateway airports/seaports. At this stage a qualitative approach should be applied. The third and final stage concentrates on the specific site selection based on the quantitative approach, i.e. The distribution centre should be place where the integration of volumes transported and distance involved is minimum and also the total distribution cost is minimum.
2.13.1 Decision-aid Techniques and Models
Several operations management books (Stevenson, 2007; Barnes, 2008; Greasley, 2009) have their sections on facility location selection techniques and some common influencing factors as reviewed in the previous section. Accordingly to works of Simchi-Levi, et al. (2003), Rushton, et al. (2006), and Bowersox and Closs (1996), there are three categories for tools used to support location analysis. The first type is the analytic techniques. The second type techniques are the mathematical optimisation techniques which can be subdivided into two types: the exact algorithms that find least-cost solution; and the heuristics algorithms that find good solution. And the third type of techniques is simulation models that provide a mechanism to evaluate specific design alternatives created by designer. The simulation models will not, however, be included in the discussion.
Accordingly to Randhawa and West (1995), the facility location problem can be approached by considering the location search space as continuous or discrete. Continuous space allows facilities to be located anywhere in the two-dimensional space; it normally assumes that the transportation costs are proportional to some distance measure between the facilities. Though easy to solve, the continuous approach may yield impractical results. The discrete space approach limits the number of possible locations to a finite set of predetermined sites, and the transportation costs are not necessarily function of distances.
Four common types of techniques found on these books namely: (1) the Centre of Gravity Method – i.e. finding a location that minimises the distribution costs; (2) the Locational Cost-Volume analysis – i.e. comparing the total costs between location alternatives by graph plotting; (3) the Factor Scoring – i.e. finding the location alternative with highest composite score; and (4) the Transportation model – i.e. a linear programming model that shows location alternative with the most optimal solution (the lowest costs).
2.13.2 The Centre of Gravity Method
The Centre of Gravity Method (CoG) is a method for locating a distribution centre that minimises the distribution costs. The main assumption of this method is the distribution cost is a linear function of the distance and the quantity transported, and that the quantity transported is fixed for the duration of the journey (Stevenson, 2007 & Greasley, 2009). The locations of destinations are presented on the map with coordinate X and Y in an accurate scale. The location of the distribution point should be located at the centre of gravity of the coordination calculated by these following equations:
Where
= Quantity to be transported to destination i
= x coordination of destination i
= y coordination of destination i
= x coordinate of centre of gravity
= y coordinate of centre of gravity
This technique is commonly used to solve location problems at a macro level. The method is applied to solve location problems in many fields other than location of a distribution centre such as school, fire centres, community centres, and such, taking into consideration location of hospitals, population density, highways, airports, and businesses (Stevenson, 2007).
Bender (1994) argues that the CoG approach had became obsolete because of the replacement of other computerised approach including linear programming. He also discusses the limitation of the approach which ignores all constraints, such as capacity, financial, operational, legal, and all cost other than transportation. It is also assume that all the transportation costs are directly proportional to distance, and independent of the direction of traffic.
2.13.3 Locational Cost-Volume Analysis
This method is an economic comparison of location alternatives which involves determining the fixed and variable costs for each location alternative. The method indicates which location is suitable for a particular volume level by analysing the mix of fixed and variable costs. The fixed cost plus variable costs line is plotted for each location alternative on the graph and the location with the lowest total cost line at the expected volume level is chosen. A total revenue line can also be plotted on the same graph to compare which location alternative has the earliest breakeven point if the objective is to consider the quickest breakeven location (Stevenson, 2007). The equation for expressing the cost is:
Where
TC = Total distribution cost
VC = Variable cost per unit
X = Number of units produced
FC = Fixed costs
This type of economic analysis is very common tool to compare which options have the highest rate of return and is not only limited to location problems. However, Stevenson (2007) suggests that, in most situations, it is very important that other factors other than costs must also be considered. The Locational cost-volume analysis alone is not sufficient to make decision.
2.13.4 Factor Rating Method
The Factor Scoring method is sometimes known as weighted scoring or point rating, which attempts to take a range of considerations into account when choosing a location. Then technique starts by indentifying the relevant factors, then assign a weight to each factor that indicate the importance compared with other factors, given that all the weight sum up to one. Scores then have to be given by decision makers to each factor for all location alternatives. The total weighted scores for each location alternative are then calculated by multiplying the factor weight by the score for each factor, and sum the results for each location alternative. The alternative with highest score is chosen unless it fails to meet the minimum threshold, if there is one (Stevenson, 2007).
The drawback of this method is identifying and determining the appropriate factors and weighting for each factor. Factors like quality of living and labour attitude are intangible factors and hard to quantify. Greasley (2009) suggested an approach to compare the tangible and intangible factors by conducting an ‘intangible factors only assessment’ by the method, and then determine if the difference between the intangible scores is worth the cost of the difference in tangible costs between the location alternatives.
Data collection, statistical estimates, optimization and simulation models, and economic analysis are some of the methods used to assess quantitative attributes. Qualitative attributes represent subjective factors for which it is generally difficult to define a natural measurement scale. Descriptive classes or interval scales (for example, 0 to 10) can be established to enable a numerical value to be assigned to represent how a site scores with respect to a particular attribute (Randhawa & West, 1995).
Linear Programming and location problems
Linear Programming is one of the most widely used strategic and tactical logistics planning tools. The transportation model helps decision maker to decide the facility location based on the transportation costs. The model is very useful as it can compare the resulting total costs for each location alternative. Other costs like production costs can also be included in the model by determining the cost on a per-unit basis for each location. There are three major pieces of information needed to use the model as following (Stevenson, 2007; Balakrishman, et al., 2007): a) list of origins and each one’s supply quantity per period; b) list of the destinations and each ones’ demand per period; and c) the unit cost of transporting items from each origin to each destination. The method can be used to solve for optimal or near-optimal locations. Even though the optimisation models are designed to provide an optimal solution, they can be used to analyze a problem under different scenarios (different combinations of constraints and cost parameters). The result would be a set of location alternatives that are the preferred choices under different operating conditions. Furthermore, examination of a solution will generally result in the identification of more than one specific site. Such sites may then be further analyzed and compared using a multi-criteria model (Randhawa & West, 1995).
There are many types of mathematical programming models and they can be classified accordingly a variety of conditions. Aikens (1985) classified distribution location models accordingly to: a) whether the underlying distribution network (arcs and/or modes) is capacitated or incapacitated; b) the number of warehouse echelons, or levels (zero, single, or multiple); c) the number of commodities (single or multiple); d) the underlying cost structure for arcs and/or nodes (linear or nonlinear); e) whether planning horizon is static or dynamic; f) the patterns of demand (e.g. deterministic or stochastic, influence of location, etc.); g) The ability to accommodate side constraints (e.g. single-sourcing, choice of only one from candidate subset, etc.).
Aiken (1985) gives some examples of types of distribution location mathematical programming models: a) Simple incapacitated facility location model; b) Simple incapacitated multi-echelon facility location model; c) Multi-commodity incapacitated facility location model; d) Dynamic incapacitated facility location model; e) Capacitated facility location models; f) Generalised capacitated facility location model; g) Stochastic capacitated facility location model; and h) Multi-commodity capacitated single-echelon facility location model.
Diabat, et al. (2009) also show that the techniques can be applied to solve location-inventory problems which finds the number of warehouses to establish , their locations, the customers that are assigned to each warehouse, and the size and time of orders for each warehouse so as to minimise the sum of inventory. Melo, et al. (2009) review many literatures related to facility location problem that show that linear prog
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选址决策对企业成功的影响
2.1简介
当今竞争激烈的市场要求公司尽可能有效地提供产品和服务。分销策略是成功的关键。分销网络的关键组成部分之一是仓库位置。选址决策被认为是一项长期的商业战略决策。正确的选址决策可以显著改善业务流程和性能，并带来相对于竞争对手的竞争优势（即成本节约、服务质量等）。另一方面，如果做出了一个糟糕的选址决定，公司同样会付出时间、金钱和机会。位置决策的环境是动态的，通常被描述为多标准决策。
此外，全球化和信息技术的快速发展改变了位置问题的特点。根据Yang和Lee（1997），设施选址有两个主要趋势。首先，人们对在全球市场上获得潜在竞争优势的兴趣越来越大。其次，作为新设施的所在地，中小型社区对许多企业更有吸引力。这两种趋势受到更先进的通信技术、更好的交通基础设施系统、国家间贸易自由化等因素的影响。这使公司能够选择他们认为最具优势的设施（即土地成本、劳动力成本、熟练劳动力可用性等）。
本章将首先确定公司为什么需要改进其物流系统，然后定义组织战略和物流战略之间的联系，然后定义仓库在分销战略中的一般作用。然后，它将介绍公司在做出选址决策时通常考虑的影响选址的因素。最后，在本章的后半部分，它将介绍用于位置决策的决策辅助技术和模型的文献综述。
2.2物流系统和不断变化的商业环境为什么我们需要改变我们的物流运营和战略？我们需要改变的主要原因是我们生活的环境在不断快速地变化。为了在这种无情的环境中生存，企业被迫改变。Rushton等人（2006）给出了许多因素，包括增加客户需求、缩短产品生命周期、改变技术、增加竞争对手的压力等。Rushton等（2006）提出的变革压力如图1所示。
图1影响物流系统的压力
2.3物流战略
物流战略应旨在在给定的客户服务水平上建立最合适的存储和运输组合。高效的物流和分销策略应降低总物流成本，并必须考虑分销链中各种补货活动的相互作用（Rushton等人，2006；Teo&Shu，2004年）。
Chopra和Meindl（2004）认为，成功的分销系统有四个驱动因素：（1）设施——位置、容量、运营方法和仓储方法；（2） 库存——周期库存、安全库存、季节性库存和采购；（3） 运输——运输方式、路线和网络设计，以及内部或外包决策；以及（4）信息——推送或拉动、协调和信息共享、预测和综合规划以及赋能技术。Bowersox和Closs（1996）提出了类似的观点，但他们也增加了另一个驱动因素，即“网络设计”。他们还声称，古典经济学经常忽视设施位置和整体网络设计的重要性。类似地，但更详细地说，Alling和Tyndall（1994）确定了使物流运营成功的十条原则。它们是：（1）将物流与企业战略联系起来；（2） 全面组织物流；（3） 利用信息技术的力量；（4） 强调人力资源——认识到优质人力资源的重要性；（5） 形成战略联盟；（6） 注重财务业绩；（7） 以达到最佳服务水平为目标；（8） 管理细节——注意细节，因为这可以节省大量费用；（9） 利用物流量——通过整合运输量、库存等；以及（10）测量性能并对其作出反应。
此外，在考虑分销战略时，仓储战略是一个重要的组成部分，通常决策者或物流规划者必须回答以下问题：（1）仓储设施应为自有、租赁或租赁的，（2）仓库的最佳规模和数量是多少，（3）仓库的最优位置是什么，（4）每个仓库位置应储备什么产品线，以及每个仓库位置应该为哪些市场区域提供服务。（Stock&Lambert，2001；Bowersox&Closs，1996；Simchi Levi等人，2003；Bowersox&Closs，96；Geoffrion&Powers，1995；Bender，1994；Stock&Lanbert，2001；Greasley，2009）
将物流战略与商业战略相匹配实现战略匹配的重要关键是公司能够在响应能力和效率之间找到最符合业务战略的平衡。无论公司选择实施何种战略，都会产生影响。必须根据业务战略评估所选物流和分销战略的影响。通常，这些可能涉及进行一些定性分析，而这些分析无法得出良好的定量指标。这将影响的主要领域是（Rushton等人，2006）：a）资本成本——这是新设施、新设备等的成本。在某些情况下，资本限制可能会排除其他有吸引力的选择；b） 运营成本——最低运营成本通常是选择方案的主要标准。在某些情况下，考虑到未来的灵活性，可以接受增加的运营成本；c） 客户服务——尽管应该根据客户服务目标制定选项，但必须检查所选的短名单，以确定所达到的客户服务水平。为了降低成本，组合的平衡可能已经发生了变化。可能需要增加靠近客户的库存，以提高服务可靠性。2.5实现战略匹配的障碍正如Chopra和Meindl（2004）以及其他作者很少提及的那样，尽管在供应链中实现战略匹配有许多因素和影响，但实现同样目标也有许多障碍。战略匹配障碍的例子很少：a）产品的多样性——产品种类的增加往往会增加不确定性，而不确定性往往会增加成本并降低系统内的响应能力；b） 产品生命周期——产品生命周期的缩短也往往会增加不确定性，减少实现战略匹配的机会窗口；c） 要求越来越高的客户——客户要求他们购买的产品实现更快、质量更好、物有所值，公司必须能够提供这些产品来维持其业务；d） 供应链所有权的碎片化——纵向一体化程度较低的结构可能导致难以协调以实现战略匹配；e） 全球化的影响&外国参与者的入侵带来的困难。值得注意的是，这些因素与第2.2节中确定的推动物流系统改进需求的因素相同。
2.6物流和配送规划框架
许多作者一致认为，在规划物流和配送时，第一步也是最重要的一步是确定组织的目标和战略。然后是第二步，即详细了解系统的当前位置。程序的其余部分是确定备选方案、分析备选方案、比较和评估结果以及制定规划和实施。下图3展示了Rushton等人（2006）的配电规划方法。
图2：物流和配送规划方法（Rushton等人，2006年）
2.7仓库的最佳数量
仓库的最佳数量可以通过使用成本计算模型来找到，该模型考虑了可变成本，特别是运输和运营成本。很少有设施提供低成本的向内运输，但提供高成本的向外运输，因为它们平均离客户更远。另一方面，更多数量的设施可能会给入境运输带来更高的成本，但出境运输的成本更低，因为它们平均离客户更近。另一个随设施数量而变化的成本是运营成本。更多的设施意味着公司必须承担更昂贵的运营成本。运营成本也因设施规模而异。一般来说，较大的设施具有规模经济性；然而，情况并非总是如此。运营大型设施的更高成本可能来自监督、沟通、效率低下等方面的成本（Attwood&Attwood，1992；鲍尔索克斯和克洛斯，1996年；Waters，2003年；Chopra和Meindl，2004年；Rushton等人，2006年）。图4以图形方式说明了设施数量与产生的成本之间的关系。
图3成本与设施数量之间的关系。
需要持有库存
在规划和设计物流和配送系统之前，了解公司需要库存的原因是非常重要的。供应链最常见的目标是有效地平衡需求和供应。正如大多数人所理解的那样，不可能使需求需求与供应的波动精确同步或平衡。因此，库存是为了在供应和需求之间提供缓冲。Rushton等人（2006）回顾了库存的重要原因，如下所示：a）降低生产成本——尽可能长时间地保持生产运行，因为设置机器的成本往往很高；b） 适应需求的变化——通过持有一定水平的安全库存来避免缺货；c） 考虑可变的供应（交付周期），以弥补生产商和供应商供应的任何延误；d） 为了降低购买成本——通常有下订单的管理成本，持有额外的库存可以降低这些成本；e） 利用数量折扣——如果大量订购，通常每件商品的价格会更低；f） 考虑到季节性波动——某些产品在一年中的某个时间很受欢迎，零售商通常在需求淡季堆积库存以满足旺季的需求；g） 考虑到价格波动/投机——某些产品的价格，例如钢铁，由于各种原因而波动。一些公司为了迎合这一需求而大量购买；h） 帮助生产和分销业务更顺利地运行&库存是为了“脱钩”两种不同的活动；i） 为客户提供即时服务–库存使公司能够在需要时尽快提供商品和服务，以最大限度地提高销售机会。这在竞争激烈的市场中至关重要；j） 以最大限度地减少因缺乏备件而造成的生产延误——生产商品或服务所需的机械故障可能会给企业带来高昂的成本。一旦机器发生故障，就有备件来修理是一种优势；k） 通过在不同过程之间提供半成品库存来促进生产过程（在制品）。
2.9仓库的作用
为什么企业需要仓库？企业需要仓库的原因有很多。仓库除了提供储存和向生产商或零售商供应材料或成品外，还有许多作用，如前一节所述。事实上，仓库还有许多其他角色和功能，可以根据Bowersox和Closs（1996）的经济和服务进行分类。从经济学的角度来看，当通过提供设施降低总物流成本时，仓库在经济上是合理的。在服务的基础上，当整个物流系统能够在时间和地点能力方面提供更好的服务时，仓库是合理的。
以下是仓库的一些常见角色（Bowersox&Closs，1996；Higginson&Bookbinder，2005；Rushton等人，2006年）：
作为批量生产/散杂货整合中心——批量生产和散杂货是仓库/DC的传统功能。在散杂货设施中，大量的进口货物被聚集在一起，通常用于产品混合和创建合并的出口货物。批量生产设施或整合中心将少量的几种产品组合成更小、更大的产品组合。
作为交叉对接站——交叉对接是一个接收产品的过程，偶尔会与不同的产品组合到同一目的地，然后在最早的时间发货，而不需要储存。交叉对接有很多好处，包括：更快的产品流，没有库存堆积，减少了产品处理，并由于消除了这些活动而降低了成本。
作为转运设施的作用——转运是指将货物从一辆车上取下并装载到另一辆车的过程。只有当有充分的理由改变运输方式或车辆类型时，才会发生这种情况。
作为装配厂的角色——惠普的配送中心就是装配厂角色的一个很好的例子。它还受益于延期的想法，这允许产品差异化到后期阶段。产品设计为使用通用零件，并在仓库进行组装。
作为产品履行中心，其主要职能是找到订购的产品并直接交付给最终客户。亚马逊仓库就是一个很好的例子。
充当退货仓库——主要功能是检查退货并将其分为可维修、重新包装、转售或回收的货物。
2.10运输
根据Chopra和Meindl（2004），公司设定的服务目标水平决定了运输在公司竞争战略中的作用。如果公司的目标客户的主要标准是价格，那么公司可以使用运输来降低产品成本，而牺牲责任感。但更多的时候，公司试图通过库存和运输来实现效率和响应能力之间的正确平衡。
通常在物流规划中，根据运输成本做出任何改变的决定。根据Rushton等人（2006），运输成本可分为三种主要类型。第一个是固定成本——无论车辆行驶10公里还是100公里，这些成本都必须承担，可能包括车辆折旧、执照费、保险等。根据各种原因，这些成本可能因车辆而异。第二类是可变成本——这些成本与车辆的活动有关，即车辆行驶的距离。成本变量最明显的例子是燃料成本。最后一种是间接成本——这些成本是由整个车队承担的间接成本。它们可能是运营车辆所需的通常业务管理费用，即员工工资、电话、互联网和其他管理费用。
2.11选址决策目标
仓库选址是一个复杂的过程，涉及多个定性和定量标准。根据组织的目标和战略，选址决策通常有多个目标。Current等人（1990）将设施选址问题的目标分为四大类，即：（1）成本最小化；（2） 以需求为导向；（3） 利润最大化；（4） 环境问题，以及这些目标往往相互重叠。对于零售企业来说，成本最小化和利润最大化往往是主要目标。
2.12仓库选址的影响
有效地确定新仓库的潜在位置非常重要。通常，这些位置必须满足各种条件，潜在位置应满足所有要求。潜在地点应考虑到未来的需求，该决定应至少在未来三到五年内对公司产生影响（Simchi Levi等人，2003）。
许多作者（Chase等人，2004年；Barnes，2008年）认为，设施位置的选择受到两个原则的影响。第一个是由于基于时间的竞争、贸易协议和运输成本，需要靠近客户。第二个是需要靠近劳动力、原材料、专业技能和能力等资源的获取途径。当一个组织对地点的选择做出决定时，通常会考虑这两个原则。业务运营的特点（即制造商或服务提供商）将决定应考虑的因素的权重。
Barnes（2008）从国际角度研究了选址决策，其中影响设施选址的因素更多地是在数量和复杂程度上。然而，这些因素可以适用于国内设施的位置。以下是主要因素列表，其本身包括Barnes（2008）给出的几个子因素：成本；劳动特点；基础设施接近供应商；接近市场/客户；靠近母公司设施；接近竞争；生活质量；法律和监管框架；经济因素；政府和政治因素；社会和文化因素；以及特定位置的特征。
Bowersox和Closs（1996）专注于物流网络战略背景下的仓库选址分析。他讨论了三种仓库定位模式，即市场定位仓库、制造定位仓库和中间定位仓库。它们暗示了Chase等人（2004）和Barnes（2008）提出的两个原则的相似思想。他们还从运输经济和库存经济的角度讨论了仓库位置。此外，他们结合了最小总成本系统的概念，其中总库存成本和运输成本的总和是最小的，以设计仓库网络。
从许多文献中回顾的潜在仓库位置的条件或属性总结如下：
现场相关因素
区域因素
土地成本/大小/土壤特性/排水
接近市场
建设成本/租赁成本/租赁费用
靠近供应商
交通设施/成本
接近竞争对手
分区限制
接近工业
社区因素
地理特征
生活质量/生活成本
天气特征
公共设施可达性
劳动力成本/可用性/技能
税
能源可用性/成本
环境法规
电信设施
地方政府支持/激励措施
政治事务和监管
持续性
交通基础设施
2.13设施选址问题的方法和技术
在本节中，我们将回顾在许多文献中发现的方法、技术和方法。
Bowersox和Closs（1996）声称，在位置决策中需要复杂的建模和分析技术，因为位置分析非常复杂，数据密集。造成复杂性的原因是，地点的数量乘以备选地点的数量，再乘以每个地点的库存策略。同时，数据强度是由详细的需求和运输信息的要求引起的。此外，设施选址过程因环境立法和相关政治问题的影响而变得复杂（Bowersox&Closs，1996）。
Thai和Grewal（2005）提出了配送中心选址的概念框架，该框架由三个主要阶段组成。第一阶段是根据重心原则确定配送中心的一般地理区域。第二阶段是确定配送中心和相关门户机场/海港的位置备选方案。在这一阶段，应采用定性方法。第三个也是最后一个阶段集中于基于定量方法的具体选址，即配送中心应位于运输量和所涉及距离的整合最小、总配送成本最小的地方。
2.13.1决策辅助技术和模型
几本运营管理书籍（Stevenson，2007；Barnes，2008；Greasley，2009）都有关于设施选址技术和一些常见影响因素的章节，如前一节所述。根据Simchi Levi等人（2003）、Rushton等人（2006）以及Bowersox和Closs（1996）的工作，用于支持位置分析的工具有三类。第一类是分析技术。第二类技术是数学优化技术，可细分为两类：找到最小成本解的精确算法；以及找到良好解决方案的启发式算法。第三类技术是模拟模型，它提供了一种机制来评估设计者创建的特定设计方案。然而，模拟模型将不包括在讨论中。
根据Randhawa和West（1995），可以通过将位置搜索空间视为连续或离散来解决设施位置问题。连续空间允许设施位于二维空间中的任何位置；通常假设运输成本与设施之间的距离成比例。虽然很容易解决，但连续方法可能会产生不切实际的结果。离散空间方法将可能位置的数量限制在有限的一组预定地点，并且运输成本不一定是距离的函数。
这些书中有四种常见的技术，即：（1）重心法——即找到一个将分销成本降至最低的地点；（2） 位置成本量分析——即通过绘图比较位置备选方案之间的总成本；（3） 因素评分——即找到综合得分最高的位置备选方案；以及（4）运输模型——即一个线性规划模型，显示具有最优化解决方案（最低成本）的位置备选方案。
2.13.2重心法
重心法（CoG）是一种将配送成本降至最低的配送中心定位方法。该方法的主要假设是配送成本是距离和运输量的线性函数，并且运输量在旅途中是固定的（Stevenson，2007&Greasley，2009）。目的地的位置以精确的比例显示在地图上，坐标为X和Y。分布点的位置应位于通过以下方程计算的坐标重心处：
哪里
=运往目的地i的数量
=x目的地i的协调
=y目的地i的协调
=x重心坐标
=y重心坐标
这种技术通常用于在宏观层面上解决位置问题。该方法适用于解决除配送中心位置以外的许多领域的位置问题，如学校、消防中心、社区中心等，同时考虑到医院位置、人口密度、高速公路、机场和企业（Stevenson，2007）。
Bender（1994）认为，CoG方法已经过时，因为它取代了包括线性规划在内的其他计算机化方法。他还讨论了该方法的局限性，该方法忽略了所有限制，如容量、财务、运营、法律以及除运输外的所有成本。还假设所有的运输成本与距离成正比，与交通方向无关。
2.13.3区位成本量分析
该方法是对位置备选方案的经济比较，包括确定每个位置备选方案中的固定成本和可变成本。该方法通过分析固定成本和可变成本的组合来指示哪个位置适合特定的容量水平。为图表上的每个位置备选方案绘制固定成本加可变成本线，并选择在预期容量水平下总成本线最低的位置。如果目标是考虑最快的盈亏平衡地点，也可以在同一张图上绘制总收入线，以比较哪个地点的备选方案具有最早的盈亏平衡点（Stevenson，2007）。表示成本的方程式为：
哪里
TC=总分销成本
VC=单位可变成本
X=生产的单位数量
FC=固定成本
这种类型的经济分析是比较哪些选择具有最高回报率的非常常见的工具，并且不仅限于位置问题。然而，Stevenson（2007）认为，在大多数情况下，还必须考虑成本以外的其他因素，这一点非常重要。仅凭区位成本量分析不足以做出决策。
2.13.4因子评级方法
因素评分法有时被称为加权评分或分数评定，它试图在选择地点时考虑一系列因素。然后，该技术从识别相关因素开始，然后为每个因素分配一个权重，表明与其他因素相比的重要性，假设所有权重加起来为一。然后，决策者必须对所有位置备选方案的每个因素进行评分。然后通过将因子权重乘以每个因子的得分来计算每个位置备选方案的总加权得分，并对每个位置备选的结果求和。除非未能达到最低阈值（如果有的话），否则会选择得分最高的备选方案（Stevenson，2007）。
这种方法的缺点是识别和确定适当的因素以及每个因素的权重。生活质量和劳动态度等因素是无形的，难以量化。Greasley（2009）提出了一种比较有形和无形因素的方法，通过该方法进行“仅无形因素评估”，然后确定无形分数之间的差异是否值得地点备选方案之间有形成本差异的代价。
数据收集、统计估计、优化和模拟模型以及经济分析是用于评估定量属性的一些方法。定性属性代表主观因素，通常很难定义自然测量量表。可以建立描述性类别或区间量表（例如，0到10），以便能够指定一个数值来表示网站如何就特定属性得分（Randhawa&West，1995）。
线性规划与定位问题
线性规划是应用最广泛的战略和战术后勤规划工具之一。运输模型有助于决策者根据运输成本来决定设施的位置。该模型非常有用，因为它可以比较每个位置备选方案的总成本。通过确定每个地点的单位成本，也可以将生产成本等其他成本包括在模型中。使用该模型需要三个主要信息，如下所示（Stevenson，2007；Balakrishman等人，2007）：a）每个时期的来源和每个时期的供应量列表；b） 目的地列表和每个时段的需求；以及c）将物品从每个来源地运输到每个目的地的单位成本。该方法可用于求解最优或接近最优的位置。即使优化模型被设计为提供最佳解决方案，它们也可以用于分析不同场景（约束和成本参数的不同组合）下的问题。其结果将是一组位置备选方案，这些方案是不同操作条件下的首选方案。此外，对解决方案的检查通常会识别出一个以上的特定地点。然后可以使用多标准模型对这些地点进行进一步分析和比较（Randhawa&West，1995）。
有许多类型的数学规划模型，它们可以根据各种条件进行相应的分类。Aikens（1985）对配电位置模型进行了相应的分类：a）底层配电网络（电弧和/或模式）是否有能力或无能力；b） 仓库梯队或级别的数量（零、单个或多个）；c） 商品数量（单个或多个）；d） 弧和/或节点的基本成本结构（线性或非线性）；e） 规划范围是静态的还是动态的；f） 需求模式（例如确定性或随机性、位置的影响等）；g） 适应侧面约束的能力（例如，单一来源、仅从候选子集中选择一个等）。
Aiken（1985）给出了一些配电网选址数学规划模型类型的例子：a）简单的无能力设施选址模型；b） 简单的无能力多级设施选址模型；c） 多商品无能力设施选址模型；d） 动态丧失能力设施位置模型；e） 容量设施位置模型；f） 广义容量设施位置模型；g） 随机容量设施选址模型；以及h）多商品容量的单梯队设施选址模型。
Diabat等人（2009）还表明，这些技术可以应用于解决位置库存问题，即找到要建立的仓库数量、它们的位置、分配给每个仓库的客户以及每个仓库的订单规模和时间，以最大限度地减少库存总额。Melo等人（2009）回顾了许多与设施选址问题有关的文献，这些文献表明
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