http://repub.eur.nl/res/concept/jel-M11/ Recent publications classified by JEL Code M11 en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/38235/ 2013-01-08T00:00:00Z This research provides a new way to validate and compare buy-till-you-defect [BTYD] models. These models specify a customer’s transaction and defection processes in a non-contractual setting. They are typically used to identify active customers in a com- pany’s customer base and to predict the number of purchases. Surprisingly, the literature shows that models with quite different assumptions tend to have a similar predictive performance. We show that BTYD models can also be used to predict the timing of the next purchase. Such predictions are managerially relevant as they enable managers to choose appropriate promotion strategies to improve revenues. Moreover, the predictive performance on the purchase timing can be more informative on the relative quality of BTYD models. For each of the established models, we discuss the prediction of the purchase timing. Next, we compare these models across three datasets on the predictive performance on the purchase timing as well as purchase frequency. We show that while the Pareto/NBD and its Hierarchical Bayes extension [HB] models perform the best in predicting transaction frequency, the PDO and HB models predict transaction timing more accurately. Furthermore, we find that differences in a model’s predictive performance across datasets can be explained by the correlation between behavioral parameters and the proportion of customers without repeat purchases. Korkmaz, E. Kuik, R. Fok, D. http://repub.eur.nl/res/pub/38213/ 2012-11-30T00:00:00Z A Forecast Support System (FSS), which generates sales forecasts, is a sophisticated business analytical tool that can help to improve targeted business decisions. Many companies use such a tool, although at the same time they may allow managers to quote their own forecasts. These sales forecasters (managers) can take the FSS output as their input, but they can also fully ignore the FSS out- comes. We propose a methodology that allows to evaluate the forecast accuracy of these managers, relative to the FSS, while taking aboard latent variation across managers' behavior. We show that the results, here for a large Germany-based pharmaceutical company, can in fact be used to manage the sales forecasters by giving clear-cut recommendations for improvement. Bruijn, B. de Franses, Ph.H.B.F. http://repub.eur.nl/res/pub/25987/ 2011-08-01T00:00:00Z Many e-tailers providing attended home delivery, especially e-grocers, offer narrow delivery time slots to ensure satisfactory customer service. The choice of delivery time slots has to balance marketing and operational considerations, which results in a complex planning problem. We study the problem of selecting the set of time slots to offer in each of the zip codes in a service region. The selection needs to facilitate cost-effective delivery routes, but also needs to ensure an acceptable level of service to the customer. We present a fully automated approach that is capable of producing high-quality delivery time slot offerings in a short amount of time. Computational experiments reveal the value of this approach and the impact of the environment on the underlying trade-offs. Savelsbergh, M.W.P. Fleischmann, M. Agatz, N.A.H. Campbell, A. http://repub.eur.nl/res/pub/25988/ 2011-08-01T00:00:00Z Many e-tailers providing attended home delivery, especially e-grocers, offer narrow delivery time slots to ensure satisfactory customer service. The choice of delivery time slots has to balance marketing and operational considerations, which results in a complex planning problem. We study the problem of selecting the set of time slots to offer in each of the zip codes in a service region. The selection needs to facilitate cost-effective delivery routes, but also needs to ensure an acceptable level of service to the customer. We present a fully automated approach that is capable of producing high-quality delivery time slot offerings in a short amount of time. Computational experiments reveal the value of this approach and the impact of the environment on the underlying trade-offs. Savelsbergh, M.W.P. Fleischmann, M. Agatz, N.A.H. Campbell, A. http://repub.eur.nl/res/pub/22812/ 2011-03-19T00:00:00Z This paper explores how standardization education can be implemented at the national level. Previous studies form the main source for the paper. This research shows that implementation of standardization in the national education system requires policy at the national level, a long term investment in support, and cooperation between industry, standardization bodies, academia, other institutions involved in education, and government. The approach should combine bottom-up and top-down. The paper is new in combining previous findings to an underpinned recommendation on how to implement standardization education. Vries, H.J. de http://repub.eur.nl/res/pub/22722/ 2011-02-17T00:00:00Z Sequencing unit load retrieval requests has been studied extensively in literature for conventional single-deep automated warehousing systems. A proper sequence can greatly reduce the makespan when carrying out a group of such requests. Although the sequencing problem is NP-hard some very good heuristics exist. Surprisingly the problem has not yet been investigated for compact (multi-deep) storage systems, which have greatly increased in popularity the last decade. This paper studies how to sequence a group (or block) of storage and retrieval requests in a multi-deep automated storage system with the objective to minimize the makespan. We adapt well-known sequencing heuristics for the multi-deep system, and propose and evaluate a new heuristic: percentage priority to retrievals with shortest leg (PPR-SL). Our results show the PPR-SL heuristic consistently outperforms all the other heuristics. Generally, it can outperform the benchmark first-come first-served (FCFS) heuristic by 20-70%. The nearest neighbor (NN) heuristic that performs very well in conventional single-deep storage systems, appears to perform poorly in the multi-deep system; even worse than FCFS. In addition, based on FCFS and PPR-SL, we find robust rack dimensions yielding a short makespan, regardless of the number of storage and retrieval requests. Yu, Y. Koster, M.B.M. de http://repub.eur.nl/res/pub/22444/ 2011-02-11T00:00:00Z Modern society is highly dependent on a reliable railway system for workforce mobility and easy access to the cities. However, the daily operations of a large passenger railway system are subject to unexpected disruptions such as rolling stock breakdowns or malfunctioning infrastructure. In a disrupted situation, the railway operator must adapt the timetable, rolling stock and crew to the modified conditions. This adaptation of resource allocations requires the solution of complex combinatorial problems in very short time and thus represents a major challenge for the involved dispatchers. In this thesis we develop models and solution methods for the rescheduling of the rolling stock during disruptions. The models incorporate service aspects (such as seat capacity), efficiency aspects (such as number of kilometers driven by the rolling stock), and process related aspects (such as the need for night-time relocation of rolling stock). The thesis contains applications of the developed models in three different contexts. First, we present a framework for applying the rescheduling models in the highly uncertain environment of railway disruption management, and we demonstrate the trade-off between computation time and solution quality. Second, we embed the rolling stock rescheduling models in a simulation framework to account for the dynamic passenger behavior during disruptions. This framework allows us to significantly decrease the delays experienced by passengers. Third, we apply the rescheduling models to real-life planning problems from the short-term planning department of the Netherlands Railways. The models lead to a considerable speed-up of the process and significant savings. Nielsen, L.K. http://repub.eur.nl/res/pub/22156/ 2011-01-13T00:00:00Z Over the years, after sales service business in capital goods and high tech sectors has experienced significant growth. The drivers for growth are higher service profits, increased competitions, and primary market contractions. The enablers for growth include information driven service processes and a move from one size fit all oriented warranty contracts to service level agreement offerings that differ in service prices and response guarantees. Although, these trends provide an opportunity to the service providers to match their service resources to the time varying service requirements of a heterogeneous customer base, the tools and techniques to support decision makers are lacking as of to date. In this thesis, we aim to make a small contribution in closing this gap. We gain business environment related insights of after sales service by studying it at a major computer equipment manufacturer. After sales service is a complex task that is accomplished by making a series of strategic, tactical, and operational decisions in maintenance services management, spare parts logistics management and spare part returns management. We exclusively focus on operational and tactical decisions in spare parts logistics management. We identify that customer information, or more specifically installed base information is a valuable source to support spare parts logistics decisions at the operational and tactical levels. We present an execution technique for spare parts logistics that uses installed base information to provide differentiated service to a heterogeneous customer base and results in additional profits for the service provider. Finally, we study execution decisions in spare parts logistics and spare part returns management for their interrelation. We highlight that explicit consideration of this interrelation yields additional benefits. Jalil, M.N. http://repub.eur.nl/res/pub/21869/ 2011-01-01T00:00:00Z This paper investigates the antecedents and consequences of two product advantage components: product meaningfulness and product superiority. Product meaningfulness concerns the benefits that users receive from buying and using a new product, whereas product superiority concerns the extent to which a new product outperforms competing products. The present paper argues that scholars and managers should make a deliberate distinction between the two components because they are theoretically distinct and also have different antecedents and consequences. Data were collected through an online survey on 141 new products from high-tech companies located in The Netherlands. The results reveal that new products need to be meaningful as well as superior to competing products to be successful. This finding is consistent with the prevailing aggregate view on product advantage in the literature. However, the results also show that the effects of the two components on new product performance are moderated by market turbulence. Although each component is important in that it forms a necessary precondition for the other to affect new product performance under circumstances of moderate market turbulence, meaningfulness is most important for new product performance in turbulent markets where preferences have not yet taken shape. In contrast, when markets become more stable, the uniqueness of meaningful attributes decreases, and new products that provide advantage by fulfilling their functions in a way that is superior to competing products are more likely to perform well. In addition, the study shows that the firm's customer and competitor knowledge processes independently lead to product meaningfulness and superiority, respectively. The findings also reveal that under conditions of high technological turbulence the customer and competitor knowledge processes complement each other in creating product meaningfulness and superiority. This implies that the level of technological turbulence puts requirements on the breadth of firms' market knowledge processes to create a new product with sufficient advantage to become successful. The paper concludes that neglecting the distinction between product meaningfulness and superiority when assessing a new product's advantage may lead to an incomplete insight on how firms can improve the performance of their new products. Rijsdijk, S.A. Langerak, F. Hultink, E.J. http://repub.eur.nl/res/pub/21681/ 2010-12-01T00:00:00Z We analyze the impact of (alliance) network exposure on the speed and extent of adoption of the business model as being one explanatory factor for diffusion controlling for actor specific characteristics and embeddedness in the network. In order to explain how existing national regulation moderated this relationship and whether it succeeded in its risk-limiting mission by moderating global adoption patterns and risk-bearing behavior among financial institutions we estimate various history event analysis model i.e. standard Cox and extended frailty models. We find strong support for the role of network exposure rather than social learning, the impact of regulatory effort on patterns of adoption and the role of country clusters for diffusion in the financial sector. Cuntz, A.N. Blind, K. http://repub.eur.nl/res/pub/21527/ 2010-11-25T00:00:00Z To add value, manufacturing and service operations depend on workers to do the job. As a result, the performance of these operations is ultimately dependent on the performance of individual workers. Simultaneously, workers are major stakeholders of the firm. Workers spend a considerable amount of time in their lives at their job and depend on that job to sustain themselves and their families. As a result, firms wishing to satisfy their primary stakeholders should consider workers’ job satisfaction in the design of their operations. Especially given that job satisfaction can promote other positive outcomes for the firm, including lower personnel turnover and accident rates. This thesis addresses the key question of how common operations management decisions may have an impact on a worker’s individual performance and his job satisfaction. In particular, we first provide a literature survey of psychology and ergonomics linking operations decision variables with performance and job satisfaction. Next, we study the effects of assigning goals on performance and work pace regulation. We identified steady work pace regulation patterns associated with challenging goals. Finally, we studied the problem of where to store items in a warehouse such that efficiency (cycle time) and well-being (discomfort) criteria are balanced. We found that both criteria have a certain degree of alignment and that simultaneous improvements in both criteria are possible. Larco Martinelli, J.A. http://repub.eur.nl/res/pub/21084/ 2010-10-21T00:00:00Z Passenger railway operators meticulously plan how to use the rolling stock and the crew in order to operate the published timetable. However, unexpected events such as infrastructure malfunctions, or weather conditions disturb the operation every day. As a consequence, significant changes, such as cancellation of trains, to the timetable must be made. If these timetable changes make the planned rolling stock and crew schedule infeasible, one speaks of a disruption. It is very important that these schedules are fixed such that no additional cancellations of trains are necessary. Nowadays this rescheduling is still done manually by the dispatchers in the control centers. In this thesis we use Operations Research techniques to develop solution approaches for crew rescheduling during disruptions. This enables us to solve the basic operational crew rescheduling problem in a short amount of computation time. Moreover, we studied an extension to the basic problem where the departure times of some trains may be delayed by some minutes. We show that this can lead to significantly better solutions for some real-life instances. Furthermore, we presented two new quasi robust optimization approaches that deal with the uncertainty in the length of the disruption. The computational study reveals that one of these approaches outperforms a naive approach in many cases. We believe that the methods developed in this thesis provided the foundation for a decision support system for railway crew rescheduling. Potthoff, D. http://repub.eur.nl/res/pub/19234/ 2010-10-16T00:00:00Z This paper discusses how a manufacturer and its retailers interact with each other to optimize their product marketing strategies, platform product configuration and inventory policies in a VMI (Vendor Managed Inventory) supply chain. The manufacturer procures raw materials from multiple suppliers to produce a family of products sold to multiple retailers. Multiple types of products are substitutable each other to end customers. The manufacturer makes its decision on raw materials’ procurement, platform product configuration, product replenishment policies to retailers with VMI, price discount rate, and advertising investment to maximize its profit. Retailers in turn consider the optimal local advertising investments and retail prices to maximize their profits. This problem is modeled as a dual simultaneous non-cooperative game (as a dual Nash game) model with two sub-games. One is between the retailers serving in competing retail markets and the other is between the manufacturer and the retailers. This paper combines analytical, iterative and GA (genetic algorithm) methods to develop a game solution algorithm to find the Nash equilibrium. A numerical example is conducted to test the proposed model and algorithm, and gain managerial implications. Yu, Y. Huang, G.Q. http://repub.eur.nl/res/pub/20994/ 2010-10-12T00:00:00Z Planning the transport of maritime containers from the sea port to final destinations while using multiple transport modes is challenged by uncertainties regarding the time the container is released for further transport or the transit time from the port to its final destination. This paper assesses the value of information in container transport in terms of multiple performance dimensions, i.e. logistics costs, reliability, security, and emissions. The analysis is done using a single period model where a decision maker allocates arriving containers to two transport modes (slow, low price, no flexible departure times, versus fast, high price, flexible departure times). We construct a frontier of Pareto optimal decisions under each of the information scenarios and show that these frontiers move in a favorable direction when the level of information progresses. Each of the Pareto frontiers help strike the balance between the aforementioned performance dimensions. The mathematical results are illustrated using two numerical examples involving barge transport and train transport. Zuidwijk, R.A. Veenstra, A.W. http://repub.eur.nl/res/pub/21222/ 2010-10-01T00:00:00Z Purpose – The purpose of this paper is to show that necessary condition hypotheses are important in operations management (OM), and to present a consistent methodology for building and testing them. Necessary condition hypotheses (“X is necessary for Y”) express conditions that must be present in order to have a desired outcome (e.g. “success”), and to prevent guaranteed failure. These hypotheses differ fundamentally from the common co-variational hypotheses (“more X results in more Y”) and require another methodology for building and testing them. Design/methodology/approach – The paper reviews OM literature for versions of necessary condition hypotheses and combines previous theoretical and methodological work into a comprehensive and consistent methodology for building and testing such hypotheses. Findings – Necessary condition statements are common in OM, but current formulations are not precise, and methods used for building and testing them are not always adequate. The paper outlines the methodology of necessary condition analysis consisting of two stepwise methodological approaches, one for building and one for testing necessary conditions. Originality/value – Because necessary condition statements are common in OM, using methodologies that can build and test such hypotheses contributes to the advancement of OM research and theory. Dul, J. Hak, A. Goertz, G. Voss, C. http://repub.eur.nl/res/pub/19928/ 2010-07-01T00:00:00Z Scheduling is essential when activities need to be allocated to scarce resources over time. Motivated by the problem of scheduling barges along container terminals in the Port of Rotterdam, this thesis designs and analyzes algorithms for various on-line and off-line scheduling problems with time lags. A time lag specifies a minimum time delay required between the execution of two consecutive operations of the same job. Time lags may be the result of transportation delays (like the time required for barges to sail from one terminal to the next), the duration of activities that do not require resources (like drying or cooling down), or intermediate processes on non-bottleneck machines between two bottleneck machines. For the on-line flow shop, job shop and open shop problems of minimizing the makespan, we analyze the competitive ratio of a class of greedy algorithms. For the off-line parallel flow shop scheduling problem with time lags of minimizing the makespan, we design algorithms with fixed worst-case performance guarantees. For two special subsets of scheduling problems with time lags, we show that Polynomial-Time Approximation Schemes (PTAS) can be constructed under certain mild conditions. For the fixed interval scheduling problem, we show that the flow shop problem is solvable in polynomial time in the case of equal time lags but that it is NP-hard in the strong sense for general time lags. The fixed interval two-machine job shop and open shop problems are shown to be solvable in polynomial time if the time lags are smaller than the processing time of any operation. Zhang, X. http://repub.eur.nl/res/pub/19881/ 2010-06-30T00:00:00Z The problem of access arises in industries where inputs from monopolistic and competitive markets are complementarily needed to provide a service. In these circumstances, the firm controlling the monopolistic segment has incentives to deter competition in the competitive segments (markets) to recover profits foregone by regulation (Paredes, 1997). In the port industry, for example, a number of services need to be jointly provided to complete the logistics chain: pilotage, towage, stevedoring, storage, etc. Without any of these, cargo cannot be delivered. In ports where a terminal constitutes a natural monopoly, an integrated terminal operator has incentives to deter competition in the markets of services that are necessary to complete the logistics chain, since this would allow him to charge disproportionate prices and extract monopolistic rents. This strategy can be implemented by preferential treatment to itself or sister companies, or by restricting competitors access to the terminal. To avoid such situations from occurring, regulators have two options. They can either (i) forbid integration between terminal operators and carriers or, (ii) establish a framework under which all service providers are allowed to access and use the terminal under reasonable conditions. As suggested by Vickers (1995), the first option (vertical separation) may create non-trivial transaction costs that result in higher prices for the consumers, for which the second option (the implementation of access policies) constitutes a more desirable policy. However, formulating access policies is not an easy task. If access conditions are too high, a limited number of entrants will use the terminal, allowing providers to obtain economic rents. If conditions are too relaxed, an excess of entry may occur, thus reducing the terminal operator’s incentives to adequately maintain and expand the infrastructure (Laffont and Tirole 1994). The objective of this thesis is to analyze the characteristics of access policies implemented in the telecommunications, electricity supply, natural gas and railways industries, and to use the lessons learned from these experiences to propose a model suitable for the port industry. Defilippi, E.F. http://repub.eur.nl/res/pub/19867/ 2010-06-24T00:00:00Z In this study, we develop and analyze models incorporating some of the dynamic aspects of inventory systems. In particular, we focus on two major themes to be analyzed separately: nonstationarity in demand rate and unfixed purchasing prices. In the first part of the study, we consider an inventory system with a nonstationary demand rate. In particular, we consider critical service parts subject to obsolescence. Inventory management of such items is notoriously difficult due to their slow moving character and the high risks involved when they are not available or no more needed. In practice, there is a need for policies tailored for service parts taking these aspects into account and easy to implement. We propose an obsolescence based control policy and investigate its performance and impact on costs. We find that ignoring obsolescence in the control policy increases costs significantly and early adaptation of base stock levels can lead to important savings. In the second part of the study, we consider an inventory system where the supplier offers price discounts at random points in time. We extend the literature by assuming a more general backordering structure. That is, when the system is out of stock, an arriving customer either decides to be backlogged with a certain probability or leaves the system and becomes a lost sale. We derive equations to calculate optimal policy parameters and demonstrate that allowing backorders in face of random deal offerings can result in considerable savings. Pinçe, C. http://repub.eur.nl/res/pub/19742/ 2010-06-10T00:00:00Z The development of logistics has offered a wide range of new business opportunities for transport operators. Shipping lines have been taking advantage of these opportunities and have expanded their business scope beyond the movement of cargo, to include, for example, coordination among transport modes, route rationalisation and even value added logistics services. Carriers offer today transportation as part of integrated global supply chain solutions in an attempt to provide a better service to their customers as well as improve their bottom lines. This appears to be a winning strategy since an increasing number of industry players are investing in logistics operations and infrastructure. The offering of products and services jointly as a package or bundle is a common marketing strategy in a variety of industries and also appears to be a successful strategy for enhancing shipping lines’ competitiveness and profitability. Only limited research is available though to better understand under what conditions such bundled sales are possible; what attitude shippers show towards this industry trend; how bundling strategies could be developed optimally; and how they could be priced. This thesis is a contribution to research in this area and provides an analysis of the viability and the benefits of bundling strategies in the container industry, and specifically with reference to the joint provision of ocean transportation and other logistics services. Acciaro, M. http://repub.eur.nl/res/pub/19678/ 2010-06-01T00:00:00Z The area under Receiver Operating Characteristic (ROC) curve, also known as the AUC-index, is commonly used for ranking the performance of data mining models. The AUC has many merits, such as objectivity and ease of interpretation. However, since it is class indifferent, its usefulness while dealing with highly skewed data sets is questionable, to say the least. In this paper, we propose a simple alternative scalar measure to the AUCindex, the Area Under an Kappa curve (AUK). The proposed AUK-index compensates for the above basic flaw of the AUC by being sensitive to the class distribution. Therefore it is particularly suitable for measuring classifiers’ performance on skewed data sets. After introducing the AUK we explore its mathematical relationship with the AUC and show that there is a nonlinear relation between them. Kaymak, U. Ben-David, A. Potharst, R.