A production/remanufacture model with returns’ subassemblies managed differently

This paper considers a production-remanufacturing inventory model for a single product, where constant demand is satisfied from the inventory of newly produced and remanufactured items. Although the available models in the literature imply that collected used units (or returns) are disassembled for recovery purposes, these models really do not treat them as such. Contrary, the returns are assumed to be recovered as whole units, perhaps, for simplicity. This assumption may not capture the benefits reaped from product recovery programs. This paper addresses this limitation in the literature and assumes that each unit of a used product is collected and disassembled into components, where these components are sorted into subassemblies, which are fed back into the production-remanufacturing process. The returned subassemblies are remanufactured and reassembled to represent a second source of as-good-as-new units of the end-product. For this multi-component inventory problem, the question that needs to be answered is whether, or not, extreme strategies of either pure remanufacturing or pure production are more economical than a mixed strategy (one that combines both strategies). A mathematical model is developed that accounts for the inventories of subassemblies. The results suggested that not accounting for the disassembled components of a product leads to inappropriate inventory decisions that are not environmentally sound.     

An inventory control model with consideration of remanufacturing and product life cycle

This paper investigates inventory control policies in a manufacturing/remanufacturing system during the product life cycle, which consists of four phases: introduction, growth, maturity, and decline. Both demand rate and return rate of products are random variables with normal distribution; the mean of the distribution varies according to the time in the product life cycle. Closed-form formulas of optimal production lot size, reorder point, and safety stock in each phase of the product life cycle are derived. A numerical example is presented with sensitivity analysis. The result shows that different inventory control policies should be adopted in different phases of the product life cycle. It is also found that the optimal production lot size and reorder point are not sensitive to the phase length and the demand changing rate.     

An extended production/recycling model with stationary demand and return rates

A production–recycling system is investigated. A constant demand can be satisfied with production and recycling. The used items are bought back and then recycled. The non-recycled products are disposed of. Two types of models will be analyzed. The first model examines the EOQ-related costs and minimizes the relevant costs. The second model generalizes the first model with the introduction of the cost function with linear waste disposal, recycling, production and buyback costs. It is asked whether the pure (either production or recycling) or mixed strategies are optimal and it will be shown that under these circumstances the mixed strategies are dominated by the pure strategies. The paper generalizes a former model proposed by the authors for the case of one recycling and one production batch to the case of arbitrary batch numbers.     

A production rate control policy for stochastic repair and remanufacturing systems

We consider the control of a manufacturing system responding to planned demand at the end of the expected life of each individual piece of equipment and unplanned demand triggered by a major equipment failure. The difficulty of controlling this type of production system resides in the variable nature of the remanufacturing process. In practice, remanufacturing operations for planned demand can be executed at different rates, referring to different component replacement and repair strategies. We formulate this problem as a multi-level control problem and propose a suboptimal control policy. The proposed control policy is described by inventory thresholds triggering the use of different execution modes. Determination of the control policy parameters is based on parameter optimization of analytical cost expressions. A numerical example based on a real case is presented. Our analysis demonstrates that the use of the proposed control approach can lead to a significant reduction in the total average cost, as compared to current practices.     

Robust optimal policies of production and inventory with uncertain returns and demand

We consider an inventory and production planning problem with uncertain demand and returns, in which the product return process is integrated into the manufacturing process over a finite planning horizon. We first propose an inventory control model for the return and remanufacturing processes with consideration of the uncertainty of the demand and returns. Then a robust optimization approach is applied to deal with the uncertainty of the problem through formulating a robust linear programming model. Moreover, properties on the robust optimization model are studied, and an equivalent robust optimization model based on duality theory is obtained which allows the solutions to be derived more efficiently. Finally, we provide a set of numerical examples to verify the effectiveness of the approach and analyze the effects of the key parameters on the solutions.     

An integrated production planning model for molds and end items

This study develops a mathematical modelling framework for simultaneously generating production plans for molds and the end items that are made with them. The inputs considered are the item demand (assumed constant over an infinite planning horizon), holding costs and shortage costs, together with the molds’ statistical lifetime distribution (in terms of number of uses) and costs pertaining to amortization, preventive replacements and corrective replacements.     

The role of free economic zones in global supply chains—a case of reverselogistics

Schengen border crossings are moving from former European borders southeastwards. These changes influence some socioeconomic positions of regions and availability of human resources in the nodes of global supply chains. Free Economic Zone (FEZ) has been considered as a tool to make the flow of goods and the flow of human resources less exposed to risk. Considering the production function in activity cells of a global supply chain, the perturbations of NPV of activities in total chain are expressed in cases, where the availability of human resources and perturbations of lead time takes place, both of which are the result of activities at border crossings. The extended MRP approach with an extension to distribution and reverse logistic part of a supply chain is used to develop the model for evaluating the influence of the lead-time perturbations and perturbations in availability of properly skilled human resources in different regions separated by Schengen borders. Tax exemption in an FEZ is presented as a compensation for the negative impact of Schengen border on the net present value of a global supply chain and consequently as the compensation for shortages and costs of properly skilled workers. The paper gives answer to the question, what is the level of reduction of tax burden in the FEZ of accession countries, which is only a compensation for the higher labour costs, additional administrative costs and the cost of risks assumed at border crossings. We have explained why we are not able to talk about an unfair competition of producers in an FEZ’s atall.     

An inventory and order admission control policy for production systems with two customer classes

In this paper we examine a Markovian single-stage system producing a single item to satisfy demand of two different customer classes. A simple threshold type heuristic policy is proposed for the joint control of inventories and backorders. Explicit forms of the steady-state probabilities under this policy are derived and used to assess the average profit rate of the system and determine the optimal control parameters. Certain properties of the average profit rate are established and used to develop computationally efficient algorithms for finding the optimal control parameter values. Numerical results show that the proposed policy is a very good approximation of the optimal policy and outperforms other commonly used policies.     

The effects of perceived market and learning orientation on assessed organizational capabilities

This study extends prior research by exploring the effects of managerial representations of market and learning orientation on perceived industrial firm capabilities. Cognitions that managers use to make sense of their environment impact competitive strategy decisions. Extant research has found market and learning orientation concepts to be empirically distinct and to have independent and synergistic effects on organizational performance. The present study generally supports hypotheses relating to independent effects of market and learning orientation viewpoints on perceptions of specific capability domains. Findings hold implications for managing the development of organizational capability portfolios as well as for future research aimed at understanding cognitions related to competitive advantage dynamics.     

An iterative approach to item-level tactical production and inventory planning

In this paper, we propose an iterative approach to jointly solve the problems of tactical safety stock placement and tactical production planning. These problems have traditionally been solved in isolation, even though both problems operate in the same decision making space and the outputs of one naturally serve as the inputs to the other. For simple supply chain network structures, two stages and one or many products, we provide sufficient conditions to guarantee the iteration algorithm’s termination. Through examples, we show how the algorithm works and prove its applicability on a realistic industrial-scale problem.     

Organizational learning and market orientation: interface and effects on performance

This paper discusses the relationship between market orientation and organizational learning and, in particular, the former's contribution to the generation of double-loop learning. Although prior contributions on this topic have been controversial, the authors, departing from the principles of RBV, consider market orientation a resource capable of generating higher order organizational learning and, in this way, capable of additionally reinforcing firms' sustainable competitive advantage. The empirical study provides evidence on the existing relationship between a firm's learning and market orientation degree and the organization's economic and non-economic results. Findings indicate that learning orientation stimulates the market-oriented behavior and that it also positively affects the establishment of long-term relationships with strategic clients. Contrary to prior research a significant and positive effect on business performance is only contrasted in the case of market orientation.     

An assessment of world-wide research productivity in production and operations management

Journal publications are important to facilitate knowledge sharing among production and operations management (POM) academics and practitioners. The purpose of this study was to explore the global POM research performance based on papers published in 20 core POM journals in the past half century. The data for the study were obtained from Thomson Reuters’ Web of Science/Knowledge databases, from 1959 to 2008, when 63,776 papers were published in POM journals. The annual distribution of papers published shows a significant growth in POM research productivity over the time period 1959 to 2008. The most productive authors in these five decades were T.C. Edwin Cheng from The Hong Kong Polytechnic University, Hong Kong; Gilbert Laporte from HEC Montréal, Canada; S.K. Goyal from Concordia University, Canada; S. Eilon from the University of London, UK; and Oded Berman from the University of Toronto, Canada. The five most productive institutions were as follows: Massachusetts Institute of Technology, Georgia Institute of Technology, Columbia University, Purdue University, and the University of Michigan. The countries found to have the highest outputs were the USA, the UK, Canada, the Netherlands and Taiwan.     

Non-technical innovation: Organizational memory and learning capabilities as antecedent factors with effects on sustained competitive advantage

The aim of the present study is to analyze the role of organizational memory and learning capabilities as antecedents to non-technical innovation, comprising organizational and marketing innovation, and to examine their effect on sustained competitive advantage within a capabilities-based view (CBV) theoretical framework. For analysis of the proposed theoretical model, 159 industrial companies in Spain were sampled and a system of structural equations was modeled using partial least squares methodology. The results confirm that both organizational memory and learning capabilities favor the development of organizational innovation and marketing innovation. Furthermore, the paper shows that both types of non-technical innovation promote the achievement of sustained competitive advantage.     

A dynamic model for the optimization of decoupling point and production planning in a supply chain

In this paper, we propose a dynamic model to simultaneously determine the optimal position of the decoupling point and production-inventory plan in a supply chain such that the total cost of the deviation from the target production rate and the target inventory level is minimized. Using the optimal control theory, we derive the closed form of the optimal solution when the production smoothing policy and the zero-inventory policy are applied. The result indicates that under the production smoothing policy, the overestimation of demand rate during the pre-decoupling stage guarantees the existence of the optimal decoupling point; meanwhile the optimal decoupling point exists under zero-inventory policy when the demand rate is underestimated. Also we perform mathematical analysis on the behavior of the optimal production rate and the inventory level and the effect of problem parameters such as the length of the product life cycle and the forecast error on the performance.     

Coordination of a production network with a single buyer and multiple vendors

This article considers a single buyer sourcing a single product from a network of homogeneous suppliers. We assume a close and cooperative relationship between buyer and vendors and suggest two coordination mechanisms, which differently affect where inventory is held in the system. Accordingly, we derive analytical and heuristic solutions for both alternatives and study the relative advantage of the models in a sensitivity analysis. Finally, propositions for future research are presented.     

An improved algorithm and solution on an integrated production-inventory model in a three-layer supply chain

Ben-Daya et al. (2010) established a joint economic lot-sizing problem (JELP) for a three-layer supply chain with one supplier, one manufacturer, and multiple retailers, and then proposed a heuristic algorithm to obtain the integral values of four discrete variables in the JELP. In this paper, we first complement some shortcomings in Ben-Daya et al. (2010), and then propose a simpler improved alternative algorithm to obtain the four integral decision variables. The proposed algorithm provides not only less CPU time but also less total cost to operate than the algorithm by Ben-Daya et al. (2010). Furthermore, our proposed algorithm can solve certain problems, which cannot be solved by theirs. Finally, the solution obtained by the proposed algorithm is indeed a global optimal solution in each of all instances tested.     

An economic order quantity (EOQ) for items with imperfect quality and inspection errors

An approach similar to Salameh and Jaber (2000) has been used in this paper to produce an optimal production/order quantity that takes care of imperfect processes. An imperfect inspection process (Raouf et al., 1983) is utilized to describe the defective proportion of the received lot. That is, the inspector may commit errors while screening. The probability of misclassification errors is assumed to be known. The inspection process would consist of three costs: (a) cost of inspection (b) cost of Type I errors and (c) cost of Type II errors. The defective items, classified by the inspector and the buyer would be salvaged as a single batch that is sold at a lower price. A mathematical model is developed to depict this scenario. Numerical examples are provided to illustrate the solution procedure.     

Economic production quantity model with imperfect-quality items, two-way imperfect inspection and sales return

In practices, not only production but inspection processes are often not perfect, thereby generating defects and inspection errors. Previous imperfect-quality inventory studies, however, have mostly focused on developing cost-minimizing models that do not consider imperfect inspection processes and related defect sales return issues despite their practical significance. Thus, this study proposes a profit-maximizing economic production quantity model that incorporates both imperfect production quality and two-way imperfect inspection, i.e., Type I inspection error of falsely screening out a proportion of non-defects and disposing of them like defects and Type II inspection error of falsely not screening out a proportion of defects, thereby passing them on to customers, resulting in defect sales returns. We also consider rework and salvage in disposing of screened and returned items. Then we solve the model optimally and present numerical sensitivity analyses to provide important managerial insights into practices.     

An integrated production–distribution model for the dynamic location and allocation problem with safety stock optimization

The design and management of a multi-stage production–distribution system is one of the most critical problems in logistics and in facility management. Companies need to be able to evaluate and design different configurations for their logistic networks as quickly as possible. This means coordinating the entire supply chain effectively in order to minimize costs and simultaneously optimize facilities location, the allocation of customer demand to production/distribution centers, the inbound and outbound transportation activities, the product flows between production and/or warehousing facilities, the reverse logistics activities, etc.Full optimization of supply chain is achieved by integrating strategic, tactical, and operational decision-making in terms of the design, management, and control of activities. The cost-based and mixed-integer programming model presented in this study has been developed to support management in making the following decisions: the number of facilities (e.g. warehousing systems, distribution centers), the choice of their locations and the assignment of customer demand to them, and also incorporate tactical decisions regarding inventory control, production rates, and service-level determination in a stochastic environment. This paper presents an original model for the dynamic location–allocation problem with control of customer service level and safety stock optimization. An experimental analysis identifies the most critical factors affecting the logistics cost, and to finish, an industrial application is illustrated demonstrating the effectiveness of the proposed optimization approach.     

The environment and its impact on satisfaction with supplier performance: An investigation of the mediating effects of control mechanisms from the perspective of the manufacturer in the U.S.A.

An important question for manufacturers relates to how to conduct exchanges with suppliers when the interaction is done in an uncertain environment. Existing literature suggests the use of unilateral control (i.e., vertical control over the supplier) to reduce the negative effects of environmental uncertainty, whereas recent research on relational norms suggests bilateral control mechanisms (i.e., the norm of information sharing) as an alternative. We propose that in order to secure satisfactory performance from suppliers, manufacturers rely on different control mechanisms depending upon the level of environmental uncertainty on one hand, and the nature of interdependence in the manufacturer-supplier relationship on the other. Our empirical results based on 162 manufacturers indicate the following: 1) manufacturers' reliance on vertical control increases as environmental uncertainty and power asymmetry increase; 2) by contrast, reliance on the bilateral information sharing increases as interdependence magnitude increases and as environmental uncertainty decreases; 3) suppliers' performance, as perceived by manufacturers, increases with the use of bilateral information sharing.