A supply chain as a series of filters or amplifiers of the bullwhip effect

The bullwhip effect refers to the phenomenon of amplification and distortion of demand in a supply chain. By eliminating or controlling this effect, it is possible to increase product profitability reducing useless costs such as stock-out and obsolescence costs. The main focus of this work is to study a single-product serial supply chain in which a control parameter can switch the chain from a series of filters to a series of amplifiers of the bullwhip effect and to analyse how the optimal values of the parameters change when discontinuities in order policy are considered. Furthermore, it is also shown that the bullwhip itself it is not a good index of the chain's performance, because it does not consider the oscillations that occur in the inventories, which also may affect the supply-chain performance.     

Supplier selection-order allocation: A two-stage multiple criteria dynamic programming approach

This paper proposes a two-stage multiple criteria dynamic programming approach for two of the most critical tasks in supply chain management, namely, supplier selection and order allocation. In the first stage, to address multiple decision criteria in supplier ranking, the analytic hierarchy process (AHP) is employed. In the second stage, supplier ranks are fed into an order allocation model that aims at maximizing a utility function for the firm as well as minimizing the total supply chain costs, subject to constraints on demand, capacity, and inventory levels. A dynamic programming approach is crafted to solve the proposed bi-objective model.     

Base stock policies with degraded service to larger orders

We study an inventory system controlled by a base stock policy assuming a compound renewal demand process. We extend the base stock policy by incorporating rules for degrading the service of larger orders. Two specific rules are considered, denoted as Postpone(q,t) and Split(q), respectively. The parameter q distinguishes between regular orders (of size less than or equal to q) and larger orders. We develop mathematical expressions for the performance measures: order fill rate of the regular orders and average on-hand inventory level. We make numerical experiments where the postpone parameter t and the base stock levels of each rule are such that all customers (of both order types) are indifferent between the two rules. When comparing the difference in the average on-hand inventory levels, we can then make an assessment of the threshold value of the cost of splitting an order (which may otherwise be hard to quantify) in the rule Split(q). Our numerical results indicate that this threshold value is increasing in the variance of the order sizes. Based on the numerical experiment our conclusion is therefore that when the variance of the order sizes is low, then Postpone(q,t) seems to be a good option, while when the variance is high, then Split(q) is more competitive.     

Optimizing the storage assignment in a warehouse served by milkrun logistics

This paper addresses the problem of storage assignment in a warehouse characterized by multi-command picking and served by milkrun logistics. In such a logistic system, vehicles circulate between the warehouse and the production facilities of the plant according to a pre-defined schedule, often with multiple cycles (routes) serving different departments. We assume that a request probability can be assigned to each item and each cycle, which leads to a special case of the correlated storage assignment problem. A MIP model is proposed for finding a class-based storage policy that minimizes the order cycle time, the average picking effort, or a linear combination of these two criteria. Computational experiments show that our approach can achieve an up to 36–38% improvement in either criterion compared to the classical COI-based strategy.     

Managing carbon footprints in inventory management

There is a broad consensus that mankind must reduce carbon emissions to mitigate global warming. It is generally accepted that carbon emission trading is one of the most effective market-based mechanisms to curb the amount of carbon emissions. This paper investigates how firms manage carbon footprints in inventory management under the carbon emission trading mechanism. We derive the optimal order quantity, and analytically and numerically examine the impacts of carbon trade, carbon price, and carbon cap on order decisions, carbon emissions, and total cost. We make interesting observations from the numerical examples and provide managerial insights from the analytical results.     

Firm resources and entry-related advantages: An empirical study in China

The majority of research on order of market entry has focused on market pioneer advantages or the specialized assets that industry incumbents would need to possess. However, relatively little attention has been paid to whether and how certain firm resources or capabilities may provide latecomers with entry-related advantages. This issue is of particular interest when multinational organizations decide to enter emerging markets, such as China, where the transitional economy provides both opportunities and challenges. This study attempts to bridge this gap by discussing the entry-related advantages in terms of pioneer advantages, early follower advantages, and late entrant advantages, and by investigating how each of the entry-related advantages has unique impacts on market performance. In particular, this study examines the relations between innovation management, firm resources, entry-related advantages, and market performance simultaneously with cross-sectional data from 191 firms in China. Our findings reveal that technical resources and skills (R&S), marketing R&S, and market intelligence are associated with different advantages for market pioneers, early followers, and late entrants. Technical R&S is also found to have significant impacts on order of market entry as pioneers. Furthermore, the findings show that remarkable differences exist among the three entrant types (i.e., market pioneers, early followers, and late entrants) in their strategic approaches to attain market performance. We offer implications to foreign firms operating in China or intending to enter China's markets.     

An analysis of the end-of-aisle order picking system: Multi-aisle served by a single order picker

This study deals with an end-of-aisle order picking system in a miniload automated storage/retrieval system (AS/RS). The system has a horse-shoe style buffer at the front end of each aisle. A conveyor system delivers the containers through the buffer positions. Earlier studies for the system assumed that an order picker serves only a single aisle. In general, however, an order picker can server two or more aisles for labor cost saving, and so this paper assume that an order picker serves a number of aisles in a predetermined order. The system can be modeled as a queueing system with a limited queue length and this paper analyzes the queueing model with supplementary variable technique to find the system's long-run behavior. Then, it proposes a simple optimization model to find an optimal buffer size. To illustrate the results, some examples are included into each chapter.     

What Determined Success During the Asian Economic Crisis?—The Importance of Experiential Knowledge and Group Affiliation

This study investigated the factors that determined the change in firm performance during the Asian economic crisis. Applying a process-oriented resource-based view and MNC network theory, we argued that host country experience, industry experience, subsidiary experience, and group affiliation would influence subsidiary performance during an economic crisis. By testing the hypotheses on a sample of 1128 Japanese subsidiaries in Thailand, Indonesia, Malaysia, and Korea, we found that, among different knowledge resources that the MNC accumulated in its internationalization process, subsidiary experiential knowledge was most significant in picking the winners from the losers during the crisis. Keiretsu affiliation and the parent firms industry experience were also significant, positive factors for firms remaining profitable or even better after the crisis. However, firm size and industry effects were not related to performance.     

A simple and accurate approximation for the order fill rates in lost-sales Assemble-to-Order systems

In this paper we consider an Assemble-to-Order system with multiple end-products. Demands for an end-product follow a Poisson process and each end-product requires a fixed set of components. We are interested in the order fill rates, i.e., the percentage of demands for which all requested components are available from stock. Requested components that are not in stock are supplied via an emergency shipment and the demand for these components is lost for the stockpoint under consideration. The component lead times are deterministic and may differ per component. The inventory of each component is controlled via a base stock policy. We show that the system decomposes into subsystems which can be analyzed independently. Each subsystem can be approximated by a subsystem with exponentially distributed lead times, for which an exact evaluation exists. For big subsystems, however, this method requires considerable computational effort. Therefore, we formulate a simple and accurate approximation for the order fill rates. Our approximation uses two estimates of which one generally gives an underestimation of the order fill rate and the other one an overestimation. A weighing factor is used to combine these two estimates into an approximate value. The approximation is shown to be accurate and requires little computational effort.     

Linking maintenance strategies to performance

In order to achieve world-class performance, more and more companies are replacing their reactive, fire-fighting strategies for maintenance with proactive strategies like preventive and predictive maintenance and aggressive strategies like total productive maintenance (TPM). While these newer maintenance strategies require increased commitments to training, resources and integration, they also promise to improve performance. This paper reports the results of a study of the relationship between maintenance strategies and performance. Based on the responses from a survey of plant managers and maintenance managers, the analysis shows strong positive relationships between proactive and aggressive maintenance strategies and performance.     

Portfolio management for new product development: results of an industry practices study

Portfolio management for product innovation – picking the right set of development projects – is critical to new product success. This article reports on the new product portfolio practices and performance of a large sample of firms in North America. Reasons why portfolio management is important are identified, followed by the relative popularity of the different portfolio techniques: financial methods are first, followed by business strategy methods, bubble diagrams and scoring models. Next, how the various portfolio methods fare in terms of six performance metrics is probed. Financial methods, although the most popular and rigorous, yield the worst results overall, while top performing firms rely more on non‐financial approaches – strategic and scoring methods. The details of how some of these more popular methods are employed by firms to rate and rank development projects are also provided. Finally, managerial implications, including suggestions for making portfolio management more effective in industry, are outlined.     

Communication protocols for order management in collaborative manufacturing

Collaborative manufacturing requires efficient and cost effective communications among the partners. To provide efficient and reliable communications, this research modularizes the design of communication protocols for order management in collaborative manufacturing. Ten protocol modules have been defined and designed in this research.With the 10 protocol modules, companies can easily construct the protocols to regulate the interactions between partner companies. This research designs five protocols associated with order management in collaborative manufacturing. The protocols are also implemented in a distributed computing environment. The results indicate that the modularized protocols ensure the reliability and efficiency of communications, and reduce the complexity in protocol design.     

Order release planning with clearing functions: A queueing-theoretical analysis of the clearing function concept

We consider the problem of planning future order releases in hierarchical production planning and control systems. An established research direction is the clearing function concept: the planned material flow through a production unit is modelled by inventory balance equations for WIP and final products, and the consequences of the stochastic properties of the material flow are modelled by clearing functions, which is the functional relationship between the level of WIP and the maximum output of a work centre in a period.Using a transient M/M/1 model, our paper shows that the usual definition of a nonlinear clearing function suffers from substantial shortcomings concerning both the definition of the function and empirical estimation of its parameters. We propose an alternative transient clearing function and derive a procedure for its parameterization.     

Design of the optimal feeding policy in an assembly system

This paper describes an innovative and integrated approach to component management optimization within a production/assembly system. In a mixed-models assembly process the handling of parts and components for each work station represents a substantial variable that can greatly affect job duration and efficiency. This paper is strictly related to Assembly to Order/Manufacturing to Order (ATO and MTO) systems, where lead time has to be very short and flexibility is at its maximum level. In Assembly to Order (ATO) or Make to Order (MTO) systems, the production is increasingly getting more customized in response to the demand, thanks to the progresses reached in both manufacturing and information technologies. It is becoming increasingly possible to assemble or make products specifically in response to the requests of either end customers or retailers. As a consequence of such customization, the design of the whole system must take into direct account several elements: parts warehouses location, feeding policies and feeding systems. In some cases the collection of parts and components required picking activities, in other the movement of entire units load.In several instances experts have analyzed the problems about material centralization/decentralization, storage policies and assembly feeding problem in different and independent ways, while the problem needs an integrated approach. While many researches regarding components allocation problems in ATO and MTO systems, did not consider feeding policies, material picking, packing activities and vehicles optimization, this paper cover focuses on filling such gap using an integrated framework that considers both aspects of the problem: the centralization/decentralization of components in order to minimize the total storage costs and the right feeding policies.Feeding problems in assembly lines are some of the most important aspects to consider during the analysis and design of an assembly system, to allow the maximization of efficiency and flexibility. To reach such goals, a multi-factorial analysis has been carried out during this experiment and will validate the introduced framework. An industrial application of the introduced framework is illustrated to explain its real significant production implication.     

A new approach to job shop scheduling problems with due date constraints considering operation subcontracts

We consider a kind of job shop scheduling problems with due-date constraints, where temporal relaxation of machine capacity constraint is possible through subcontracts. In practice, this kind of problem is frequently found in manufacturing industries where outsourcing of manufacturing operation is possible through subcontract. We present a heuristic algorithm that addresses the problem by solving a series of smaller subproblems to optimality. For the sake of efficiency, the algorithm repeatedly executes in two steps—(1) improving the sequence of operations and (2) picking out the operations to be subcontracted—on bottleneck machines. Experiments are conducted for example problems, and the result of the experiment confirms the viability of the suggested algorithm.     

基于可视化技术的农产品防伪溯源监控系统设计

随着中国农产品物流规模不断壮大,农产品物流系统无法从源头保证产品采摘、包装、物流中的可信性。为了解决这个问题,提出一种现场作业可视化系统,即将可视化技术应用于农产品防伪溯源监控系统中,从而满足远程管理的需求。对相关可视化技术的一般方法进行了分析,选择COFDM作为主要解决方案。农产品防伪溯源监控系统有效克服了复杂环境下的各类干扰,将物流中的实时监控信息传送到中继通信和监控设备上,并依托公用通信网络或专用通信网络进一步实现广域范围内的实时高质量监控图像传输、存储和浏览。通过实时现场视频监控,消费者可以保证买到真实可信的高质量农产品;生产者可以提高农产品的生产、运输效率,还可以提升相应产品的信誉,促进高质量农产品的销售。     

Managing international supply: The balance between total costs and customer service

Many trading companies have taken a global approach to their supply markets, sourcing from low-cost foreign countries in order to achieve cost reductions. There remains, however, a lack of evidence that sourcing internationally actually leads to improved economic performance. This can be explained by two key challenges in terms of how to achieve a balance between: (1) purchasing and logistics costs, and (2) customer service. The purpose of this paper is to examine the organisation and management of international supply from a total cost perspective, taking into account both purchasing and logistics costs, as well as customer service and agility. Previous research into a number of Norwegian companies that have sourced from China has identified four configurations for managing international supply. This paper utilises the supply management literature and an example of a Norwegian retail and wholesale company to analyse and discuss these configurations and their effects on total costs and customer service. The paper's theoretical contribution is the conceptualisation of a total cost perspective on international supply management and the discussion of such costs in relation to customer service. This contribution may, in turn, aid companies that source from foreign, low-cost countries.     

Revenue management for make-to-order manufacturing systems with a real-life application

Abstract

Due to successful applications of revenue management in the airline industry, in recent years, there has been a growing interest to adopt revenue management in make-to-order (MTO) manufacturing systems. Several interrelated decision problems such as order acceptance/rejection, short-term capacity planning, due date assignment, and order scheduling need to be studied simultaneously in order to manage revenues effectively in MTO manufacturing systems. Both the producer’s and customer’s requirements need to be taken into account through some negotiation mechanisms that are sensitive to the service-level reputation of the manufacturing companies. In this article, we propose a new dynamic bid price–based revenue management model that considers all of the aforementioned decision problems simultaneously. A simulation optimization approach is utilized in order to determine the best possible values of control parameters for bid price, due date assignment, and price increment/reduction mechanisms. The performance of the proposed integrated revenue management model is tested on both a hypothetical example and a real problem of a bridal gown company. The computational results show that the proposed model provides significant improvements in total revenue compared to other static and dynamic bid price policies.     

Customer service strategy options: A multiple case study in a B2B setting

This study addresses the question whether customer service actually has order winning potential in B2B situations, which customer service strategies are deployed, and what determines customer service relevance. A literature review was followed by a multiple case study, using 12 organizations from different industries and from different positions in supply chains. Based on having both problem solving and transfer characteristics, four customer service strategy options are identified: customer integration, customer adaptation, logistical precision, and standard customer service. Many organizations are positioned in the least attractive customer service strategy option: customer adaptation. Partially, this is caused by difficulties in assessing the customer service capability and the customer's sensitivity for customer service. The article concludes with the theoretical and managerial implications.