1、 交通与汽车工程学院 本科生毕业设计(论文)英文翻译学生姓名: 学 号: 专 业: 年 级: 指导教师: 日 期: 交通与汽车工程学院制库存控制的编制角度分析:理论和案例研究 作者:Leonieke G. Zomerdijk*, Jan de Vries 摘 要库存控制在物流领域得到了深入讨论。现今,许多观念和技术都可以有效地控制库存。例如许多随机模型被用来确定订购数量、技术预测需求还有不同的ABC分析法。显而易见,这些观念和技术的理论背景都显示出了大量的相似之处:他们都源于运营管理学和运筹学。尽管这些观念有着可用价值,但是这种片面的方法在实践中有着他自身的局限性。在这篇文章中,我认为在处理实
2、际的库存控制的问题时要采取更为全面的思考。首先,就是要形成一种编制角度的库存控制。这个观点的中心思想库存编制环境的重要性。这就意味着除了传统的注意事项,订单数量和补货策略以及其他方面也需要注意。例如:职责的分配,库存管理权利的分配,库存信息的质量和相关的决策过程等等。这些情境因素以及传统因素形成了一个用于解决实际库存控制问题的框架图。而这个框架图的其中一个主要特征就是在分析和重新设计库存情况时事非常有用的。其次,这篇文章描述了一个研究结果的案例,而这个案例是关于从应用程序的编制视角来解决实际库存控制问题。案例研究的中心问题时非洲传教士航空组织的备件库存。案例研究表明:该编制视角在处理库存控制问
3、题上市非常有用的。这表明:库存编制环境尤其是有关人员的职责和权利是正确理解库存控制问题的必要条件。此外,这也说明编制视角导致了一个更合适的设计。关键词:案例研究,库存控制,编制角度1.前言在过去的几十年里,库存控制一直是许多论文的热门话题。它也可以当之无愧的被叫做运营领域的精华。因此,大量的观念和技术都可有效地控制库存。例如,随机模型来确定订购数量、技术预测需求以及不同类型的ABC分析。近来,管理系统,如制造资源计划(MRP)和企业资源规划(ERP)已被添加进入这一系统,然而,大多数这些计划都有着相似的理论背景,运营管理和运营研究。这就意味着这些观念和技术主要基于数学的假设和建模的库存情况。虽
4、然这种方法建立的库存控制已被证明在确定库存参数和规划资源上是很有价值的,而其价值就在于能够质疑在处理实际库存控制时出现的问题。例如:普罗素(Plossl)和韦尔奇(Welch)认为许多企业利用库存控制技术来工作但库存并没减少。另一方面,许多企业即使没有利用这些观念和技术也可以在管理总库存投资方面做得很好(Plossl and Welch, 1797, p.26)。此外,如今许多学者认为许多定量方法领域的运营管理学和运筹学不足以应付今天编制的复杂性(如:Hayes, 1998; Lovejoy, 1998; Machuca,1998)。这些学者在运营管理问题上支持一个更为广泛的范围,包括定性方面
5、和在一个编制中有着其他功能领域的联系。因此,这就需要一个库存控制的扩展视图。在本文中,我们认为在处理库存控制问题时采取编制库存环境是非常重要的。这就意味着除了传统的注意事项,如订单数量和补货策略,环境方面也需要注意。例如:职责和库存管理权限的分配、库存信息的质量和相关的决策过程。这些环境因素以及传统因素都可以在库存控制方面形成一个编制的视角。所以,这篇文章的主题就是这个编制视角的形成和实际应用。文章结构如下:首先,形成一个编制视角,为此,就需要研究编制库存环境来确定库存控制的各个方面;其次,提出一个框架图以应用编制视角来解决实际库存控制问题;然后,介绍一个已经应用了编制视角的案例的研究方法。而
6、且该案例与非洲传教士航空组织的备件库存有关。第四部分,从案例研究中得出结论。而这个结论就是运用编制环境视角能是人们更好地理解问题,而且能够重新设计一个更适合的库存情况;最后一部分总结全文。2.库存控制的编制视角在运营管理学和运筹学中可以找到关于库存控制的许多观点。传统上,有些人关注三个方面:订单数量、订购区间和库存控制系统,而且他们被公认为在库存控制中扮演着重要的角色。比如说:Plossl(1985)和Silveretal(1998)。第一个方面关注于订单数量或者订购多少。为了确定经济订货量,一些相关库存成本发挥着一定的作用,如订购成本和库存成本。第二个方面与订购区间或者订购时间有关。考虑到这
7、一点,需求量和更换规模的过程是非常重要的。最后,第三个方面就是库存管理系统。然而,一般常见与系统控制有关的主题就是ABC分类和信息系统。这三个方面代表了传统的库存情况,此外,这三个方面还被认为是提高库存控制的起点。过去的二十年间,随着运营管理学的发展和成熟,一些新观念已经被添加到库存控制的主题中。这些管理主题包括MRP,即JIT和ERP(Hayes, 1998; Leschke, 1998)。尽管近期的这些观点有着更多的定性性质,但是他们与以前的观点一样在库存控制当面都有着片面性。事实上,大多数观点对大多数库存处在同一个环境中这一事实关注很少或者根本不关注。从实用的观点来看,不能忽视库存的环境
8、设置,许多同处于一个编制环境的其他几个因素在库存控制中起着一定的作用。一般来说,这些因素是在运营管理学和运筹学之外但是还是要被考虑到这些领域之内。大多数因素与环境整合库存和信息流动有关。一个显著的例子就是库存管理职责和权限的分配。例如当企业中如果没有人负责库存或者负责人没有足够的权力时就很容易出现库存控制问题。同样的,一个缺乏控制的高库存可能是不正确的库存记录的结果或者是记录系统操作失误的结果。因此,编制环境库存也包括其他几个可以影响库存控制的方面。为了能够辨别库存编制环境的重要几个方面,它可以分为四个维度:分配任务、决策过程、沟通过程和工作人员。首先,分配任务是库存编制环境的一个重要的维度。
9、根据洛夫乔伊(1998)所说,这个维度应该是运营管理问题上的部分问题,而在这方面的相关特征是负责库存管理人员数量、他们的作用及其在企业中的职位。另一个相关特征就是责任与当局之间的分配。这些特点中的每一个特点都有可能会影响库存控制的有效性。其次,编制理论表明:决策过程会形成一个重要的编制维度(如,Daft, 1998)。就像其他编制领域,许多库存管理的决策是从年度战略到日常活动的运营决策产生的。因此,这些决策就会影响最终的库存控制。此外,库存控制的有效性取决于库存决策方式之间的相互关系。例如,很明显,由于错误信息而形成的矛盾的决定或者决策会影响库存控制的有效性。然后,沟通过程代表编制库存环境的另
10、一个维度。正如编制行为学家所强调的,沟通是所有编制操作的关键环节(如,格林伯格和巴伦,1993;罗宾斯,1993)。在这方面,考虑到库存控制沟通过程的影响是非常重要的。例如:转发的库存信息、信息质量和商品的反馈都对库存控制的有效性有重大影响。第四个也就是最后一个编制环境维度库存控制工作人员的行为。自从霍桑三四十年代的实验之后,人们普遍认识到社会各方面影响影响编制的功能(德赛尔,1988;保罗,1994)。洛夫乔伊(1998)指出人类的行为不应该在运营管理问题上被忽略。事实上,社会各方面都可以影响库存控制的有效性。例如,冲突可能会妨碍人们传递重要的库存信息。此外,权力可以阻碍库存的决策过程。同样
11、,奖赏制度、不确定性以及不适当性都会影响库存任务的执行。因此,不仅要考虑到任务分配、决策过程和沟通过程等正面方面,还要考虑到行为和潜在因素的非正面方面,这一点是非常重要的。因此,在库存控制中扮演着重要角色的四个维度应该加以识别。所以在处理库存控制的实际问题时应该考虑到这些维度,以及运营管理学和运筹学的其他注意事项。由此产生一个叫做库存控制的编制透析。而且,它有两个重要的特征。首先,库存控制这一观点着重于多样的观点。这就意味着不再只是关注于订单数量、订购区间和库存控制系统。而且,从属于编制理论和编制行为的其他方面的库存控制也会得到关注。其次,库存控制这一观点是从一个综合的观点切入的。这不仅意味着
12、许多库存控制的不同方面得到了讨论,而且不同维度之间的相关性也得到了广泛关注。这是至关重要的一个方面。因为就是这个相关性最终决定着实际情况中库存控制的有效性。例如,适当的补货策略可以抵消不恰当的责任分配带来的弊端。同样,不良的行为也可能阻碍决策和沟通过程。相关性的缺乏很容易导致利益冲突。因为众所周知,编制人员参与销售、生产和财务等不同的库存控制。(Plossl, 1985; Silver et al, 1998)。因此,需要注意几个维度在库存控制方面的相互反应,而不是各自的传统方面或者交流过程。本文的下一部分将呈现一个框架图,而这个框架图可应用于编制视角来解决实际的库存控制问题。3.集成框架图事
13、实上,就业的库存控制编制视角可以通过图2很好的展示出来。该框架图显示出了一个更能接近实际的库存控制问题的方法,它是基于一个基本的控制回路来显示底层解决问题的过程。一般来说,解决一个问题的起点是一个执行预先设定的标准以下的库存系统,在许多情况下,这些预先设定的标准时根据成本定义的。例如,一些有关成本的“性能”的库存系统是存储成本、缺货成本、订货正本和过时成本。然而,库存系统的性能是指不仅仅是明确定义的成本的标准。实际上,存货管理的主要目的是为了促进供求关系的平衡。所以任何表明不平衡的供求关系也可能指的是表现不佳的库存系统。这儿有些例子症状就是(生产)计划过程的不稳定性,加急订单的出现和低效运行的
14、生产设备。在许多情况下,一个偏离轨道的库存系统会激活一个库存系统的识别功能,而这个库存系统的许多方面都得到了研究。然后,这个识别功能能够重新设计一个新的库存系统。在这个框架图中,有一些指南识别和与设计阶段相呼应的库存控制编制视角的应用程序。首先,应用编制在解决一个库存控制的问题上在一定程度决定了编制的识别过程。这一阶段的目标就是在库存情况上达到一个清晰的认识,在库存控制问题的原因上达到一个全方面的了解。为此,库存系统需要被描述和分析。描述一个库存系统是获得一个全面的描述库存系统的重要步骤。最后的结果应该包括两个方面的详细描述:库存控制和编制环境的库存系统。这样是为了确保那些参与了库存控制问题的
15、大量因素都包含在这个描述之中。因此,第一个应用于实际库存控制的编制视角的指南通过关注任意一个已经确定了参与库存控制的维度就能描述出这样一个库存系统。对描述这样一个库存系统是非常有用的。此表呈现了一个传统方面的详细阐述、任务分配、决策过程、交流过程和库存控制的行为。每个维度分为相关方面和特点方面。虽然列出的这些特点不是面面俱到的,但是它是由一个将在库存情况方面形成相当完整的洞察力而组成的。An organizational perspective on inventory control: Theory and a case studyAbstract Inventory control is
16、a well-covered area in literature. Nowadays, many concepts and techniques are available for effectively controlling inventories. Eminent examples are stochastic models to determine order quantities, techniques for forecasting demand and different kinds of ABC analysis. Remarkably enough, the theoret
17、ical backgrounds of these concepts and techniques show a great deal of similarity: they all stem from the field of operations management and operations research. Despite the value of the available concepts, such a one-sided approach has its limitations in practice. In this article it is argued that
18、it is important to take a broader view when dealing with practical inventory control problems. First of all, an organizational perspective on inventory control is developed. The main idea behind this perspective is the importance of the organizational context of inventories. This means that in addit
19、ion to the traditional points for attention, such as order quantities and replenishment strategies, other aspects need attention as well. They are, for example, the allocation of responsibilities and authorities regarding inventory management, the quality of inventory information and the relevant de
20、cision-making processes. These contextual factors as well as the traditional factors are mapped out and integrated into a framework to be used in solving practical inventory control problems. One of the main features of the framework is that it is useful in both analyzing and redesigning an inventor
21、y situation. Secondly, this article describes the results of a case study regarding the application of the organizational perspective to a practical inventory control problem. The in Africa. The case study shows that the organizational perspective on inventory control is very helpful in dealing with
22、 inventory control problems. It is illustrated that taking into account the organizational context of inventories, especially the responsibilities and authorities of the persons concerned, is a necessity to accurately understand inventory control problems. In addition, it is illustrated that the org
23、anizational perspective leads to a more appropriate redesign.1. Introduction During the last few decades inventory control has been the topic of many publications. It may fairly be called one of the classics in operations literature. As a result, a large collection of concepts and techniques is avai
24、lable for effectively controlling inventories. There are for example stochastic models to determine order quantities,techniques for forecasting demand and different kinds of ABC analysis. Recently management systems such as manufacturing resource planning(MRP) and enterprise resource planning (ERP)h
25、ave been added. However, most of these contribution shave similar theoretical background: the field of operations management and operations research. This means the concepts and techniques are mainly based on mathematical assumptions and modeling inventory situations. Although this established appro
26、ach to inventory control has proved to be very valuable in determining inventory parameters and planning resources, its value can be questioned in dealing with practical inventory control problems. Plossl and Welch for instance state that many firms have inventory control techniques working but they
27、 are not reducing inventories. On the other hand, some others are doing a fine job of managing the total inventory investment even without these tools (Plossl and Welch, 1979, p. 26). In addition,nowadays authors realize that many of the quantitative methods from the field of operations management a
28、nd operations research are insufficient to cope with todays organizational complexity(e.g.Hayes,1998;Lovejoy, 1998; Machuca,1998). These authors favor a broader scope on operations management issues, including qualitative aspects and linkages with other functionalareas in an organization. Therefore,
29、 there seems to be a need for an extended view on inventory control. In this article we argue that it is highly important to take the organizational context of inventories into account when dealing with inventory control problems. This means that in addition to the traditional points for attention,
30、such as order quantities and replenishment strategies,contextual aspects need attention as well.They are for example the allocation of responsibilities and authorities regarding inventory management,the quality of inventory information and the relevant decision-making processes. These contextual fac
31、tors as well as the traditional factors can be integrated into an organizational perspective on inventory control. The development and practical application of this organizational perspective are the main topics of this article. The article is organized as follows. First, the organizational perspect
32、ive on inventory control is developed. To that end, the organizational context of inventories is investigated to determine aspects that play a part in inventory control. Second, a framework is presented to facilitate the application of the organizational perspective to practical inventory control pr
33、oblems. The third section of this article describes the research methodology of a performed case study in which the organizational perspective has been applied. The case study regards the spare parts inventory of a missionary aviation organization in Africa. Fourth, the results following from the ca
34、se study are presented. It can be concluded that taking the organizational context of inventories into account leads to a better understanding of the problem and to a more appropriate redesign of the inventory situation. The final section of this article summarizes the conclusions.2. An organization
35、al perspective on inventory controlWithin the area of operations management and operations research many contributions regarding inventory control can be found. Traditionally they focus on three topics that are widely recognized to play an important part in inventory control: order quantities, order
36、 intervals and inventory control systems. See, for example, Plossl (1985) and Silveret al. (1998). The first topic regards order quantities or how much to order. In order to determine economic order quantities, several costs associated with inventories play a part, such as ordering costs and invento
37、ry carrying costs. The second topic regards the order interval or when to order. In this respect demand and lead-time processes are important. Finally, the third topic regards the inventory control system. Common subjects concerning systems for controlling inventories are ABC classifications and inf
38、ormation systems. These three aspects represent the traditional characteristics of an inventory situation. In addition, they are considered to be starting points for improving inventory control. Over the past two decades, as the field of operations management has developed and matured, several new c
39、oncepts have been added to the list of relevant inventory control topics. These more management-oriented topics include MRP, just-in-time (JIT) and ERP (Hayes,1998; Leschke, 1998). Although these recent contributions have a more qualitative nature, they show the same one-sided scope on inventory con
40、trol as the previous contributions. In fact,most contributions pay little or no attention to the fact that the majority of inventories are situated in an organizational context. From a practical point of view it seems that the organizational setting of inventories should not be disregarded. Being si
41、tuated within an organizational context several other factors play a part in inventory control. In general these factors lie outside the field of operations management and operations research but should nevertheless be taken into consideration. Most factors regard the organizational incorporation of
42、 inventories and the associated information flows. A significant example concerning inventory management is the allocation of responsibilities and authorities. Inventory control problems can easily arise when for instance nobody in the organization is responsible for the inventory or the responsible
43、 person has insufficient authorities to carry out the task.Likewise, high inventory values indicating a lack of control may just be the result of inaccurate inventory records or of a reporting system that does not function well. Thus, the organizational context of inventories also contains several a
44、spects that can affect inventory control.In order to identify significant aspects in the organizational context of inventories four dimensions can be distinguished. They are the allocation of tasks, decision-making processes, communication processes and behavior of the parties involved,as displayed
45、in Fig. 1. First, the allocation of tasks is an important dimension in the organizational context of inventories. According to Lovejoy (1998) this dimension should be part of the foundations of an integrated view on operations management issues. Relevant characteristics in this respect are the numbe
46、r of people that are responsible for inventory management, their functional positions and their hierarchical positions in the organization. Another relevant characteristic is the fit between allocated responsibilities and authorities. Each one of these characteristics might influence the effectivene
47、ss of inventory control. Second, organizational theory shows that decision-making processes form a significant organizational dimension (e.g. Daft, 1998). Like in other organizational areas, many decisions are made in inventory management, varying from annual strategic decisions to operational decis
48、ions concerning day-to-day activities. The resulting inventory control is influenced by how these decisions are made. Furthermore, the effectiveness of inventory control depends on the ways in which inventory decisions relate to each other and to other decisions in the organization. It is evident th
49、at, for instance, contradicting decisions or decisions that are based on wrong information can influence the effectiveness of inventory control. Third, communication processes represent another dimension in the organizational context of inventories. As stressed by organizational behaviorists,communication is a key process underlying all aspe