E‐Procurement Infusion and Operational Process Impacts in MRO Procurement: Complementary or Substitutive Effects?

The procurement of maintenance, repair, and operating (MRO) goods has remained a relatively understudied topic in the literature. Though vital cost efficiencies can be extracted from procurement processes through investments in e‐procurement systems, there is little empirical work that addresses how such systems should be deployed within organizations. In this study, we focus on the role of e‐procurement systems in MRO procurement and study two critical aspects of infusion. The first dimension captures the depth of e‐procurement use within the procurement function, while the second dimension depicts the breadth of use. We argue that these two dimensions of e‐procurement use, and their interaction, will be related to the performance of the MRO procurement process. Using survey data from 193 service organizations and structural equation modeling techniques, we show that the two infusion dimensions are significantly associated with improved process performance. Additionally, we show a substantial substitutive effect between the two use dimensions on performance. Our work has significant implications for managers who seek to gain efficiencies by the deployment of Internet‐based technologies within operational processes. Our conceptualization of e‐procurement infusion along two dimensions provides a more fine‐grained analysis of performance benefits accruing from the infusion of information technologies within organizations.     

A METHODOLOGY FOR LABOR SCHEDULING IN A SERVICE OPERATING SYSTEM

In the increasingly competitive services sector, utilization of the labor force can make the difference between profits or losses. Until recently, service operations managers had a limited set of tools, most of them computer-based, for scheduling labor. This paper offers a manual heuristic for labor scheduling that outperforms traditional algorithmic solution approaches. Specifically, this study examines the problem of scheduling employees in service delivery system subject to demand variability. The manual heuristic proposed asigns full-time empolyees to weekly work schedules with the objective of minimizing the total number of labor hours scheduled. The performance of the manual heuristic is compared to the classical algorithmic solution and to a lower bound for a variety of demand distributions and system operating conditions. The heuristic is shown to produce a smaller work force than the classical approach in 106 of the 108 demand-operating condition patterns examined.     

Transportation Approach to Locating Plants in Relation to Potential Markets and Raw Material Sources

Proximity to the market place has been considered the most important locational factor in the literature so far. However, the growing need for frequent deliveries of materials in smaller lot sizes for just-in-time (JIT) manufacturing prefers plants closer to the raw materials sources. Locating plants for JIT manufacturing is, therefore, a problem of finding the right balance between the requirements of procurement and distribution. A comprehensive model is proposed in this paper to solve this problem. The model is solved by using the transportation algorithm and produces simultaneous decisions on procurement, production, and distribution. The model does not require plant sizes to be known a priori, but it allows upper limits to be placed on the size of each plant and raw material source. As such, optimal plant capacities along with the corresponding procurement and distribution quantities are all determined by the model solution.     

Improving the Utilization of Front-Line Service Delivery System Personnel*

There are two types of work typically performed in services which differ in the degree of control management has over when the work must be done. Serving customers, an activity that can occur only when customers are in the system is, by its nature, uncontrollable work. In contrast, the execution of controllable work does not require the presence of customers, and is work over which management has some degree of temporal control. This paper presents two integer programming models for optimally scheduling controllable work simultaneously with shifts. One model explicitly defines variables for the times at which controllable work may be started, while the other uses implicit modeling to reduce the number of variables. In an initial experiment of 864 test problems, the latter model yielded optimal solutions in approximately 81 percent of the time required by the former model. To evaluate the impact on customer service of having front-line employees perform controllable work, a second experiment was conducted simulating 5, 832 service delivery systems. The results show that controllable work offers a useful means of improving labor utilization. Perhaps more important, it was found that having front-line employees perform controllable work did not degrade the desired level of customer service.     

Procedural Justice in Procurement Management and Inclusive Interorganizational Relations: An Institutional Perspective

This paper applies the concept of procedural justice to one of the most important focal points of interorganizational relations: the purchaser–supplier relationship. The few extant studies of the concept in the purchaser–supplier domain have overlooked an important aspect of this key relationship: that is, inclusiveness in procurement. This is despite the fact that interest in the specific empirical context of supply chain links between large purchasing organizations (LPOs) and ethnic minority suppliers (EMSs) from disadvantaged communities proceeds apace on both sides of the Atlantic. Institutional theory is used to examine the form that procedural justice takes in eight case studies of LPOs from the private and public sectors, which actively engage with inclusive procurement management initiatives in England. The guiding question is twofold: ‘What may LPO approaches to installing procedural justice in procurement management entail?’ and ‘How are these approaches shaped?’ This paper identifies specific approaches to installing procedural justice for inclusive procurement and submits theoretical propositions about how these are shaped. The study contributes to a macro‐level assessment of procedural justice, i.e. interorganizational procedural justice, as a significant aspect of inclusive interorganizational relationships, which is a domain in need of theoretical development.     

基于和谐管理理论的武器装备采购质量管理研究

武器装备采购质量管理是武器装备采购方对装备需求论证、生产竞标、装备制造、监督、激励和评价等过程加以控制来提高装备质量的行为,这一行为的基本特征是复杂性。针对目前我国武器装备采购质量管理中的问题,根据和谐管理理论应对复杂性的机理,提出了武器装备采购质量管理的和谐耦合体系,并探讨了这一体系在军用飞机采购中的应用。其核心思想是同时建立设计优化机理指导下的控制机制和能动致变机理下的诱导机制,对于那些可通过优化设计的质量问题运用规定性的控制机制来解决,由人的不确定性引起的、不可用规定的硬性措施解决的质量问题用能动致变的演化机制来应对,最后还要注意两种机制之间的互动、转化和调节。     

Inventory management with variable lead-time dependent procurement cost

A reduction in the inventory replenishment lead-time allows reducing safety stock requirements and improving customer service. However, it might be accompanied by increased procurement costs because of premium charges imposed by suppliers, or higher transportation costs. This paper studies a single-stage variable lead-time inventory system with lead-time dependent procurement cost. Selection of the lead-time value represents finding the trade-off between benefits of lead-time reduction and increase in the procurement cost. A model for joint optimization of inventory and procurement costs is developed. Numerical studies are conducted to identify conditions under which lead-time reduction is favorable compared to procuring at the lowest cost.     

考虑采购资金约束的物流服务能力采购决策

以物流服务供应链为研究对象,研究集成商期初时期对服务能力批发量和期权预订量的决策、需求即将发生时期对期权执行量的决策以及需求确定时期对现货采购量的决策,构建在无采购资金约束条件下集成商的采购决策模型,求得服务集成商3个时期的采购决策.然后引入采购资金约束,分析存在采购资金约束情况下集成商各个时期的采购策略,并对比有无采购资金约束条件集成商采购策略的不同,分析采购资金约束对集成商采购策略的影响.最后,通过数据分析对研究结论进行说明和验证.     

A Study of the Impact of an Integrated Information Technology on the Time Utilization of Information Workers

This paper examines the impact of the implementation of an integrated information technology (IIT) on the time utilization of information workers as mediated by the content of the information work performed. The IIT in this study is a system of personal computers linked together in a network for sharing computing, data, and communication resources. The subjects of the study were two groups of information workers in an academic field setting. One group consisted of knowledge workers whose chief activity was to advise and counsel students. The other group represented lower level information workers who provided support service to an academic department. A two-dimensional framework was used to classify each of the activities an information worker performs relative to its importance and programmability within the context of the information work. Using work sampling methodology, it was determined that the IIT was associated with the knowledge workers' reallocation of work time to important yet relatively unstructured tasks. The lower level information workers became more efficient in performing highly structured skill-based activities. However, there was no statistically significant improvement in the effectiveness of the work completed as perceived by the clients of both groups of information workers. The results suggest that when an IIT is implemented, the manner in which newly available time is utilized depends on the nature of the information work performed by the users.     

考虑供应风险的多源应急物资采购双层规划模型

自然灾害频繁发生,事故灾难不断涌现,公共卫生事件猝不及防,社会安全风险交织叠加,给人们的生产和生活带来了巨大的风险和不确定性。在突发事件背景下,考虑应急物资供应中的各类风险,激励多源应急物资的稳定供给,受到党和政府高度重视。应急物资供应有哪些风险,如何规避这些风险,针对多种渠道的采购,如何优化采购结构。这些问题是本论文关注的重点。本文以政府、制造型企业、受灾地区民众为决策主体的三级供应链为基础,构建了上层以整个供应链系统收益最大化为目标函数、下层以供应风险最小化为目标函数的双层规划模型,对不同情景下物资采购订单的分配进行研究。在此基础上,本文以某市洪涝灾害为例进行分析,证明了模型的可行性,并探究了供应风险变化对物资采购订单分配、以及整个供应链系统收益的影响,以期为政府应急物资采购决策提供参考性建议。     

Force field analysis—A framework for strategic thinking

This article is derived from feedback which the author has analysed in the course of his work as an organization development consultant in Zambia. It is based on the experience of a large number of diverse organizations currently engaged in the process of developing ‘survival strategies’ in the field of materials management as a result of the effect of economic, geographical and geopolitical factors peculiar to the region. Some of the results are equally applicable to procurement operations in other landlocked countries in the East and Central African region. While some of the observations reflect the consequences of ineffective supply management strategies at the corporate level in the Third World context, the lessons are equally applicable to the long-range planning needs of procurement specialists and chief executives in the developed countries. Exercise material is provide to enable management development specialists to examine the approaches utilized during training sessions and to facilitate the development of assignment materials specific to their own organization.     

The Effect of Lead Time Uncertainty on Safety Stocks

The pressure to reduce inventory investments in supply chains has increased as competition expands and product variety grows. Managers are looking for areas they can improve to reduce inventories without hurting the level of service provided. Two areas that managers focus on are the reduction of the replenishment lead time from suppliers and the variability of this lead time. The normal approximation of lead time demand distribution indicates that both actions reduce inventories for cycle service levels above 50%. The normal approximation also indicates that reducing lead time variability tends to have a greater impact than reducing lead times, especially when lead time variability is large. We build on the work of Eppen and Martin (1988) to show that the conclusions from the normal approximation are flawed, especially in the range of service levels where most companies operate. We show the existence of a service‐level threshold greater than 50% below which reorder points increase with a decrease in lead time variability. Thus, for a firm operating just below this threshold, reducing lead times decreases reorder points, whereas reducing lead time variability increases reorder points. For firms operating at these service levels, decreasing lead time is the right lever if they want to cut inventories, not reducing lead time variability.     

DESIGNING HIGH-CONTACT SERVICE SYSTEMS: APPLICATION TO BRANCHES OF A SAVINGS AND LOAN*

The customer-contact model represents one of the few conceptually based approaches for designing service systems. This paper develops that concept further for high-contact systems, relative to efficiency and effectiveness notions. Four design features (contact technologies, contact training, data bases, and contact roles) are developed and a simple design methodology (built around the four design features) is presented. A demonstration of the design methodology is provided through its applications to branches of a savings and loan. Areas for additional theoretical and practical refinement of the model and the desirability of multidisciplinary research are discussed.     

Service Package Switching in Hotel Revenue Management Systems

Revenue Management Systems (RMS) are commonly used in the hotel industry to maximize revenues in the short term. The forecasting‐allocation module is a key tactical component of a hotel RMS. Forecasting involves estimating demand for service packages across all stayover nights in a planning horizon. A service package is a unique combination of physical room, amenities, room price, and advance purchase restrictions. Allocation involves parsing the room inventory among these service packages to maximize revenues. Previous research and existing revenue management systems assume the demand for a service package to be independent of which service packages are available for sale. We develop a new forecasting‐allocation approach that explicitly accounts for this dependence. We compare the performance of the new approach against a baseline approach using a realistic hotel RMS simulation. The baseline approach reflects previous research and existing industry practice. The new approach produces an average revenue increase of at least 16% across scenarios that reflect existing industry conditions.     

物资采购综合评价指标体系质量控制模型应用研究

本文依据非序列多层次目标准则建立了物资采购综合评价指标体系,应用模型参考思想构建了物资采购综合评价指标体系的质量控制模型及其目标函数,按照采购项目管理的运作程序对各个阶段的采购质量做了相应的评价,最后运用实例对以上讨论进行了定量化的分析。通过计算得到的数量指标,我们可以有效评价和控制物资采购工作,以期提高采购质量、节省经费开支。     

A Service Quality Process Map for Credit Card Processing

Evaluating marketing (external) and operations (internal) service quality performance in most organizations is a data-oriented management task that involves many variables for many different types of services. These two diverse sets of service quality information seldom “match up well” because the marketing and operations functions define and evaluate service quality “their way.” Management's interpretation of what the data “mean” often contributes to extra meetings, unnecessary disagreements within and between functional areas, and poor decision making. This situation can affect the quality and timing of decisions, and ultimately, the organization's profitability and market share. This paper quantitatively relates the customer's evaluation (perception) of service quality directly to the activities and performance criteria of the service delivery process for a credit card processing center. Basic statistical analyses and a recursive path analysis model define the relationships between marketing- and operations-based service quality information. The idea of a “service quality process map” is introduced. A service quality process map relates a flowchart of the service delivery process to the customer's perception of service using the power of multivariate data analysis. Management insights gained from an analysis of marketing (external) and operations (internal) measures of service quality performance can be used to allocate resources wisely. The objective is to gain the most improvement in the customer's perception of service for the least cost. Service quality with this type of evaluation capability can be used to gain competitive advantage in the marketplace.     

How Long Should a Customer Wait for Service?

A major concern for service managers is the determination of how long a customer should wait to be served. Services, due to the customer's direct interaction with the process, must face a trade-off between minimizing the cost of having a customer wait and the cost of providing good service. A total cost model is presented for determining how long a customer should wait when these two conflicting cost components are considered. An integral part of this model includes a measure of customer satisfaction with waiting time which is used to develop a waiting cost function. The model is then applied to a major fast food chain, using data collected at several locations. Analysis of the data reveals that the “ideal” waiting time for this firm is significantly less than the current corporate waiting time policy. Thus, as indicated by the model, a corporate policy change is recommended to provide much faster service. The adoption of such a policy would result in increased labor costs, and would simultaneously increase the firm's overall profits. Although appearing contradictory, increases in current labor costs and long-term profits are both possible when management takes the long-range perspective suggested in this paper.     

Linking long-term capacity management for manufacturing and service operations

For firms that combine manufacturing and service operations in one system, the task of managing capacity is not straightforward. New goods and services may not have the same set of competitive priorities, and the models and concepts available in the literature for service operations differ from those for manufacturing operations. We address this problem and review the concepts and models for capacity management in the long term in both streams of literature, i.e. manufacturing and services, to develop a unified framework for manufacturing and service operations. The framework creates transparency between new goods manufacturing and service operations, since the same long-term capacity management structure is used for both product types, as well as between capacity strategy and planning strategy, since new goods and services are treated simultaneously. In the framework, the concepts of chase and level strategies are redefined for service operations to allow for integration with manufacturing operations. A case study demonstrates the usefulness of the integrated approach for long-term capacity management.     

STAFFING SERVICE ACTIVITIES WITH WAITING LINE MODELS

The problem of scheduling service activities and variable tasks has traditionally been solved subjectively. The lack of objective approaches has been due to the absence of formal standards and delay costs and by the high cost of examination and measurement. Some recent developments in work measurement concepts may permit the development of more objective standards, which when used in conjunction with scientific methodology such as waiting line theory, make possible objective scheduling of the variable service type activity. The work of a salesperson in a retail store provides an example of both the variable service type activity and the waiting line problem. The manager attempts to balance the cost of service facilities (sales personnel) against the cost of a waiting line (customer ill will). The necessary data inputs for the waiting line model were obtained from field studies by means of work sampling. Computer simulation was then utilized to study various sized sales forces in an attempt to determine the most economical staff allocation.     

Master Production Scheduling Under Rolling Planning Horizons with Fixed Order Intervals

Fixed interval scheduling is studied in the context of a rolling horizon framework that is developed by building on previous work in the master scheduling area. The rolling horizon framework includes a stationary scheduling model which uses the “time fencing’concept by partitioning the planning horizon into three sections. The lengths of these sections and the frequency at which the stationary problem is updated and resolved are discussed as parameters of the rolling horizon model. Two different interpretations of the freeze interval parameter are examined, enabling confirmation and clarification of results presented in an earlier study. Details are given for three methods of calculating safety stocks as a function of rolling horizon parameters, including a method which results in optimal safety stock levels. A comparison of the safety stock methods shows that the constant safety stock method can result in inventories that are significantly above optimal under certain conditions, whereas the constant service level method consistently yields nearly optimal results.