http://repub.eur.nl/res/aut/49/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/39733/ 2013-03-01T00:00:00Z In this article, we explain how Internet retailers can learn from proven revenue management concepts and use them to reduce costs and enhance service. We focus on attended deliveries as these provide the greatest opportunities and challenges. The key driver is service differentiation. Internet retailers have strong levers at their disposal for actively steering demand, notably the offered delivery time windows and their associated prices. Unlike traditional revenue management, these demand management decisions affect both revenues and costs. This calls for a closer coordination of marketing and operations than current common practice. http://repub.eur.nl/res/pub/22767/ 2011-03-01T00:00:00Z Many of the challenges in spare parts logistics emerge due to the combination of large service networks, and sporadic/slow-moving demand. Customer heterogeneity and stringent service deadlines entail further challenges. Meanwhile, high revenue rates in service operations motivate companies to invest and optimize the service logistics function. An important aspect of the spare parts logistics function is its ability to support customer-specific requirements with respect to service deadlines. To support customer specific operations, many companies are actively maintaining and utilizing installed base data during forecasting, planning and execution stages. In this paper, we highlight the potential economic value of installed base data for spare parts logistics. We also discuss various data quality issues that are associated with the use of installed base data and show that planning performance depends on the quality dimensions. http://repub.eur.nl/res/pub/19574/ 2010-01-01T00:00:00Z This paper develops a novel framework to evaluate the integral performance of order picking systems with different combinations of storage and order picking policies. The warehousing literature on order picking mostly considers minimizing either elapsed time or distance as the sole objective, whereas warehouse managers in a supply chain have to look beyond single-dimensional performance and consider trade-offs among different criteria. Thus managers still need a unified and efficient framework to select a portfolio of appropriate order picking policies from a multi-criteria and contextual perspective. Our framework-combining data envelopment analysis, ranking and selection, and multiple comparisons-provides an efficient methodology to simultaneously analyze several interrelated problems in order picking systems with multiple performance attributes, such as service levels and operational costs. We demonstrate our approach through comprehensive evaluations of order picking policies in three low-level, picker-to-parts rectangular warehouses facing demand variations. http://repub.eur.nl/res/pub/19884/ 2010-01-01T00:00:00Z The primary objective of closed-loop supply chains (CLSC) is to improve the maximum economic benefit from end-of-use products. Nevertheless, the literature within this stream of research advocates that closing the loop also helps to mitigate the undesirable environmental footprint of supply chains. Therefore, closed-loop supply chains are assumed to be sustainable supply chains almost by definition. In this paper we analyse if and when this assumption holds. We illustrate our findings based on the Electric and Electronic Equipment (EEE) supply chain. For all phases of the supply chain, i.e. manufacturing, usage, transportation and end-of-life activities, we assess the magnitude of the environmental impacts, based on a single environmental metric, namely the Cumulative Energy Demand (CED). Given the environmental hot-spots in the Electric and Electronic Equipment supply chain, we propose useful extensions for existing CLSC optimisation models to ensure that closed-loop supply chains are at the same time sustainable supply chains. http://repub.eur.nl/res/pub/14529/ 2009-01-13T00:00:00Z Many of the challenges in spare parts logistics emerge due to the combination of large service networks, and sporadic/slow-moving demand. Customer heterogeneity and stringent service deadlines entail further challenges. Meanwhile, high revenues rates in service operations motivate companies to invest and optimize the service logistics function. An important aspect of the spare parts logistics function is its ability to support customer-specific requirements with respect to service deadlines. To support customer specific operations, many companies are actively maintaining and utilizing installed base data during forecasting, planning and execution stages. In this paper, we highlight the potential economic value of installed base data for spare parts logistics. We also discuss various data quality issues that are associated with the use of installed base data and show that planning performance depends on the quality dimensions. http://repub.eur.nl/res/pub/13556/ 2008-06-01T00:00:00Z This review addresses supply chain management issues specific to Internet fulfillment in a multi-channel environment. It provides a systematic overview of managerial planning tasks and corresponding quantitative models. Our objective is to twofold, namely to enhance the understanding of multi-channel e-fulfillment by documenting the current state of affairs, and to inspire fruitful future research by identifying gaps between relevant managerial issues and available academic literature. One of the recurrent patterns in today’s e-commerce operations is the combination of ‘bricks-and-clicks’ – the integration of e-fulfillment into a portfolio of multiple alternative distribution channels. From a supply chain management perspective, multi-channel distribution provides opportunities for serving different customer segments, creating synergies, and exploiting economies of scale. However, in order to successfully exploit these opportunities companies must master novel challenges. In particular, the design of a multi-channel distribution system requires a constant trade-off between process integration and separation across multiple channels. In addition, sales and operation decisions are ever more tightly intertwined as delivery and after-sales services are becoming key components of the product offering. http://repub.eur.nl/res/pub/12244/ 2008-04-25T00:00:00Z In this paper, we explain how Internet retailers can learn from proven revenue management concepts and use them to reduce costs and enhance service. We focus on attended deliveries as these provide the greatest opportunities and challenges. The key driver is service differentiation. Revenue management has shown that companies can do much better than a one-size-fits-all first-come-first-serve strategy when selling scarce capacity to a heterogeneous market. Internet retailers have strong levers at their disposal for actively steering demand, notably the offered delivery time windows and their associated prices. Unlike traditional revenue management, these demand management decisions affect both revenues and costs. This calls for a closer coordination of marketing and operations than current common practice. http://repub.eur.nl/res/pub/13639/ 2008-03-16T00:00:00Z Recent literature on sustainable logistics networks points to two important questions: (i) How to spot the preferred solution(s) balancing environmental and business concerns? (ii) How to improve the understanding of the trade-offs between these two dimensions? We posit that a visual exploration of the efficient frontier and trade-offs between profitability and environmental impacts are particularly suitable to answer these two questions. The visual representation of the efficient frontier, however, presents two challenges. The first is to obtain a good approximation for such frontier without enumerating all extreme efficient solutions. The second is to obtain a good visual representation of the efficient frontier. We propose a two-phased heuristic to handle these two problems. The algorithm is designed for the multi-objective linear problem with three objectives: minimize costs, cumulative energy demand and waste in a reverse logistics network. We illustrate our approach by designing a complex recycling logistics network in Germany. http://repub.eur.nl/res/pub/10176/ 2007-05-11T00:00:00Z The primary objective of closed-loop supply chains (CLSC) is to reap the maximum economic benefit from end-of-use products. Nevertheless, literature within this stream of research advocates that closing the loop helps to mitigate the undesirable footprint of supply chains. In this paper we assess the magnitude of such environmental gains for Electric and Electronic Equipments (EEE), based on a single environmental metric of Cumulative Energy Demand. We detail our analysis for the different phases of the CLSC, i.e. manufacturing, usage, transportation and end-of-life activities. According to our literature review, within the same group of EEE, results greatly vary. Furthermore, based on the environmental hot-spots, we propose extensions of the existing CLSC models to incorporate the CED. http://repub.eur.nl/res/pub/10177/ 2007-05-11T00:00:00Z Recent literature on sustainable logistics networks points to two important questions: (i) How to spot the preferred solution(s) balancing environmental and business concerns? (ii) How to improve the understanding of the trade-offs between these two dimensions? We posit that a complete exploration of the efficient frontier and trade-offs between profitability and environmental impacts are particularly suitable to answer these two questions. In order to deal with the exponential number of basic efficient points in the frontier, we propose a formulation that performs in exponential time for the number of objective functions only. We illustrate our findings by designing a complex recycling logistics network in Germany. http://repub.eur.nl/res/pub/8987/ 2006-10-20T00:00:00Z Recent literature on sustainable logistics networks points to two important questions: (i) How to spot the preferred solution(s) balancing environmental and business concerns? (ii) How to improve the understanding of the trade-offs between these two dimensions? We posit that a complete exploration of the efficient frontier and trade-offs between profitability and environmental impacts are particularly suitable to answer these two questions. In order to deal with the exponential number of basic efficient points in the frontier, we propose a formulation that performs in exponential time for the number of objective functions only. We illustrate our findings by designing a complex recycling logistics network in Germany. http://repub.eur.nl/res/pub/7901/ 2006-08-22T00:00:00Z This review addresses the specific supply chain management issues of Internet fulfillment in a multi-channel environment. It provides a systematic overview of managerial planning tasks and reviews corresponding quantitative models. In this way, we aim to enhance the understanding of multi-channel e-fulfillment and to identify gaps between relevant managerial issues and academic literature, thereby indicating directions for future research. One of the recurrent patterns in today’s e-commerce operations is the combination of ‘bricks-and-clicks’, the integration of e-fulfillment into a portfolio of multiple alternative distribution channels. From a supply chain management perspective, multi-channel distribution provides opportunities for serving different customer segments, creating synergies, and exploiting economies of scale. However, in order to successfully exploit these opportunities companies need to master novel challenges. In particular, the design of a multi-channel distribution system requires a constant trade-off between process integration and separation across multiple channels. In addition, sales and operations decisions are ever more tightly intertwined as delivery and after-sales services are becoming key components of the product offering. http://repub.eur.nl/res/pub/7320/ 2006-02-01T00:00:00Z The objective in this paper is to shed light into the design of logistic networks balancing profit and the environment. More specifically we intend to i) determine the main factors influencing environmental performance and costs in logistic networks ii) present a comprehensive framework and mathematical formulation, based on multiobjective programming, integrating all relevant variables in order to explore efficient logistic network configurations iii) present the expected computational results of such formulation and iv) introduce a technique to evaluate the efficiency of existing logistic networks.The European Pulp and Paper Industry will be used to illustrate our findings. http://repub.eur.nl/res/pub/6636/ 2005-06-07T00:00:00Z The Port of Rotterdam is a key container transshipment hub for Europe. Inland container shipping is important to connect the hinterland (40% market share). Barges visit several terminals per round-trip through the Port, thus requiring a proper planning support – to avoid planning problems such as double-bookings. A pilot version of an inter-organizational system has been build, titled APPROACH. This paper describes an industry workshop where a gamesetting was used to evaluate the current manual planning practices with the APPROACH outcome – and delivered interesting findings; both for actual implementation of the system as well as it unveiled issues for further research. http://repub.eur.nl/res/pub/6556/ 2005-05-18T00:00:00Z Sustainable supply chain management (SSCM) is a rather new phenomenon in the Operations Management/Operations Research literature. In the design of Sustainable Supply Chains the increase of transparency across the chain is essential and can be obtained through identification and traceability. Sustainable production often means a change in resource-areas and modes of transportation. Investment in sustainability implies innovations in supply chain management with accompanying costs and profits. We present a framework based on product and process innovations that provides insights in the relevant research questions for integrating Environmental Management and SCM. The framework is applied using the literature and practical case studies in this area. http://repub.eur.nl/res/pub/1806/ 2004-11-17T00:00:00Z Product flows in today’s supply chains do not end once they have reached the customer. Many products lead a second and even third or fourth life after having accomplished their original task at their first customer. Consequently, a product may generate revenues multiple times, rather than a single time. Capturing this value requires a broadening of the supply chain perspective to include new processes, known as ‘reverse logistics’, as well as multiple interrelated usage cycles, linked by specific market interfaces. Coordinating the successive product uses is key to maximizing the value generated. In this chapter, we review the field of reverse logistics. We discuss its opportunities and its challenges and indicate potential ways for companies to master them. We highlight what makes reverse logistics different from ‘conventional’ supply chain processes, but also point out analogies, and explain how both views can be integrated into an extended supply chain concept. We illustrate our discussion with examples of reverse logistics practice at IBM. http://repub.eur.nl/res/pub/2300/ 2004-01-01T00:00:00Z http://repub.eur.nl/res/pub/19886/ 2003-11-01T00:00:00Z IBM is among the pioneers recognizing the benefits of closed-loop supply chains that integrate product returns into business operations. We worked on a project exploiting product returns as a source of spare parts. Key decisions concern what recovery opportunities to use, the channel design, and coordinating alternative supply sources. Our analytic inventory-control model and a simulation model showed that procurement-cost savings largely outweigh reverse logistics costs and that information management is essential. These findings provide a basis for significantly expanding the usage of the novel parts supply source, thereby cutting procurement costs. http://repub.eur.nl/res/pub/353/ 2003-05-30T00:00:00Z The pig husbandry is an important economic sector. In the last decade, major changes have been made. As a result, farmers came together to introduce the "Eco Label pig", meeting the strong consumer and governmental call for high quality, animal friendly and environmentally friendly food. The market for Eco Label food is expected to grow enormously in the next years, asking for the development of an efficient and effective supply chain consisting of farmers, slaughter houses, wholesalers and retailers. We present some mathematical models to support decision making and evaluation of a large number of growth scenario's, using cost minimization given a number of Eco Label conditions. http://repub.eur.nl/res/pub/11390/ 2003-01-01T00:00:00Z Costs related to tires are about three percent of the operating costs of a transport fleet. Fleet operators have been trying to reduce these costs by extending the tires' useful life and by increasing their use of retreaded tires. A program to reduce tire wear can pay off only if the fleet operator and the retreader cooperate. However, the typical contract between the two leads to conflicting incentives. We devised a service contract with shared savings and cautiously chosen parameters for McGriff Treading Company, Inc., that better aligns the incentives for reducing tire costs. Apart from the optimal choice of contract parameters, managerial performance metrics and information technology systems to monitor and track costs were the key factors in the company's transition from a product to a service company. McGriff Treading now successfully uses such contracts for its intermodal and trucking clients. http://repub.eur.nl/res/pub/258/ 2002-11-25T00:00:00Z Ever more companies are recognizing the benefits of closed-loop supply chains that integrate product returns into business operations. IBM has been among the pioneers seeking to unlock the value dormant in these resources. We report on a project exploiting product returns as a source of spare parts. Key decisions include the choice of recovery opportunities to use, the channel design, and the coordination of alternative supply sources. We developed an analytic inventory control model and a simulation model to address these issues. Our results show that procurement cost savings largely outweigh reverse logistics costs and that information management is key to an efficient solution. Our recommendations provide a basis for significantly expanding the usage of the novel parts supply source, which allows for cutting procurement costs. http://repub.eur.nl/res/pub/122/ 2001-11-01T00:00:00Z Choosing packaging material for dairy products and soft drinks is an interesting issue at the moment. Discussions arise on the costs impacts and environmental impacts of both one way packaging and reusable packaging. The aim of this article is to develop an evaluation tool providing costs and environmental impacts of the PC-bottle and the GT-packs in the dairy sector, considering forward and return flows. The evaluation tool enables the user to analyse the costs and environmental impacts of a supply chain with and without return flows using scenario analyses with respect to the use of various carrier types and the number of return loops. It appears that costs differences between PC-bottles and GT-pack are quite small. The PC bottle has a better environmental profile than the GT-pack. Scenario analysis on the carriers results in the advice to use preferably roll-in-containers with direct delivery, secondly roll-in-containers with delivery via distribution centers, thirdly in case of direct delivery either cartons or crates and cartons in case of delivery via distribution centers. http://repub.eur.nl/res/pub/729/ 1999-12-22T00:00:00Z In this paper we consider the role Electronic Commerce plays and can play for Reverse Logistics. After short introductions to electronic commerce and reverse logistics, we give an overview of existing internet sites for reverse logistics. These sites can be classified as electronic markets, supply of used parts and complete reverse logistic solutions. Finally we draw some lines to the future. http://repub.eur.nl/res/pub/2275/ 1998-01-01T00:00:00Z The recovery of used products and materials is receiving growing attention as a result of depleted landfill and incineration capacities. From a logistical point of view these reuse opportunities give rise to a goods flow from the user back to the sphere of the producers. "Reverse logistics" is concerned with the management of this "reverse" goods flow. In this paper issues in reverse logistics are addressed from an operational research perspective. Recent contributions related to the areas of distribution planning and inventory management are discussed, and compared with traditional logistical settings. http://repub.eur.nl/res/pub/2244/ 1997-01-01T00:00:00Z This article surveys the recently emerged field of reverse logistics. The management of return flows induced by the various forms of reuse of products and materials in industrial production processes has received growing attention http://repub.eur.nl/res/pub/31759/ 1996-06-10T00:00:00Z http://repub.eur.nl/res/pub/19888/ 1995-01-01T00:00:00Z This article examines strategic production and operations management issues in product recovery management (PRM). PRM encompasses the management of all used and discarded products, components, and materials for which a manufacturing company is legally, contractually, or otherwise responsible. The objective of PRM is to recover as much of the economic (and ecological) value of used and discarded products, components, and materials as reasonably possible, thereby reducing the ultimate quantities of waste to a minimum. This article also discusses the relevance of PRM to durable products manufacturers. It contains a categorization of PRM decisions. A case study based on the PRM system of a multinational copier manufacturer is presented to illustrate a set of specific production and operations management issues. The experiences of two other pro-active manufacturers (BMW and IBM) are also discussed http://repub.eur.nl/res/pub/2239/ 1995-01-01T00:00:00Z http://repub.eur.nl/res/pub/31760/ 1995-01-01T00:00:00Z http://repub.eur.nl/res/pub/14349/ 1994-12-01T00:00:00Z Develops a decision support system (DSS) for the aircraft maintenance department of KLM Royal Dutch Airlines at Schiphol Airport in Amsterdam, Netherlands. Tasks of the department; Support provided by the DSS to management; Analyzing several capacity planning problems related to the size and the organization of the workforce. http://repub.eur.nl/res/pub/14358/ 1991-10-01T00:00:00Z In this paper we describe a Decision Support System (DSS) that has been developed for the aircraft maintenance department of the Dutch national airline company at the main airport in the Netherlands. The aircraft maintenance department is responsible for carrying out the regular short inspections of aircraft between their arrival at and their consecutive departure from the airport. The main resource of the aircraft maintenance department is its workforce. The DSS that has been developed can be used to support the management of the maintenance department in solving several capacity planning problems related to the size and the composition of the workforce. In this paper we give a description of the capabilities of the DSS. Furthermore, we describe the solution technique that is applied within the DSS for determining the required size and composition of the workforce. http://repub.eur.nl/res/pub/19890/ 1978-01-01T00:00:00Z In a recent paper, Lippman presents sufficient conditions for Denardo's N-stage contraction in discounted semi-Markov decision processes with unbounded rewards. In this note it is demonstrated that Lippman's conditions may be replaced by weaker conditions which even imply l-stage contraction. The verification of the conditions of this note is somewhat easier.