http://repub.eur.nl/res/concept/jel-R4/ Recent publications classified by JEL Code R4 en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/40138/ 2013-05-22T00:00:00Z This is the specification for the Power Trading Agent Competition for 2013 (Power TAC 2013). Power TAC is a competitive simulation that models a “liberalized” retail electrical energy market, where competing business entities or “brokers” offer energy services to customers through tariff contracts, and must then serve those customers by trading in a wholesale market. Brokers are challenged to maximize their profits by buying and selling energy in the wholesale and retail markets, subject to fixed costs and constraints. Costs include fees for publication and withdrawal of tariffs, and distribution fees for transporting energy to their contracted customers. Costs are also incurred whenever there is an imbalance between a broker’s total contracted energy supply and demand within a given time slot. The simulation environment models a wholesale market, a regulated distribution utility, and a population of energy customers, situated in a real location on Earth during a specific period for which weather data is available. The wholesale market is a relatively simple call market, similar to many existing wholesale electric power markets, such as Nord Pool in Scandinavia or FERC markets in North America, but unlike the FERC markets we are modeling a single region, and therefore we do not model location-marginal pricing. Customer models include households and a variety of commercial and industrial entities, many of which have production capacity (such as solar panels or wind turbines) as well as electric vehicles. All have “real-time” metering to support allocation of their hourly supply and demand to their subscribed brokers, and all are approximate utility maximizers with respect to tariff selection, although the factors making up their utility functions may include aversion to change and complexity that can retard uptake of marginally better tariff offers. The distribution utility models the regulated natural monopoly that owns the regional distribution network, and is responsible for maintenance of its infrastructure and for real-time balancing of supply and demand. The balancing process is a market-based mechanism that uses economic incentives to encourage brokers to achieve balance within their portfolios of tariff subscribers and wholesale market positions, in the face of stochastic customer behaviors and weather-dependent renewable energy sources. The broker with the highest bank balance at the end of the simulation wins. Ketter, W. Collins, J. Reddy, P. Weerdt, M.M. de http://repub.eur.nl/res/pub/39844/ 2013-04-12T00:00:00Z We estimate welfare losses of policies that provide on-street parking permits to residents almost free of charge in shopping districts. Our empirical results indicate that parking supply is far from perfectly price elastic, implying that there are substantial welfare losses related to under-priced parking permits. Our results suggest that the provision of residential parking permits in shopping districts induces a yearly deadweight loss of at least euro 500 per permit, which is about 30% of the supply cost of a parking place in shopping districts. Ommeren, J. van Groote, J. de Mingardo, G. http://repub.eur.nl/res/pub/37225/ 2012-09-04T00:00:00Z This article explores the determinants of road traffic crash fatalities in India. In addition to income, the analysis considers the sociodemographic population structure, motorization levels, road and health infrastructure and road rule enforcement as potential factors. An original panel data set covering 25 Indian states is analyzed using multivariate regression analysis. Time and state fixed-effects account for unobserved heterogeneity across states and time. The rising motorization, urbanization and accompanying increase in the share of vulnerable road users, that is, pedestrians and two-wheelers, are the major drivers of road traffic crash fatalities in India. Among vulnerable road users, women form a particularly high-risk group. Higher expenditure per police officer is associated with a lower fatality rate. The results suggest that India should focus, in particular, on road infrastructure investments that allow the separation of vulnerable from other road users on improved road rule enforcement and should pay special attention to vulnerable female road users. Grimm, M. Treibich, C. 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/23650/ 2011-04-04T00:00:00Z At the edge of cities, park-and-ride (P + R) facilities pop up with the aim to intercept motorists from traveling into the city. However, these facilities also appear attractive to public transport users who start using their cars for getting to the P + R location. This paper analyzes the overall impact of P + R on total car traffic and social welfare by means of a discrete modal choice model. The results show that the distribution of individuals' preferences for car over public transport is the main determinant of this impact. P + R has a larger traffic reducing effect if more individuals prefer their car. At the same time, the shift of traffic from city to periphery improves welfare. These effects get stronger when a P + R facility provides a superior access to the mainline public transportation network. Karamychev, V.A. Reeven, P.A. van 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/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/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. http://repub.eur.nl/res/pub/19594/ 2010-05-21T00:00:00Z Collaboration between firms in order to coordinate supply chain operations can lead to both strategic and operational benefits. Many advanced forms of collaboration arrangements between firms exist with the aim to coordinate supply chain decisions and to reap these benefits. This dissertation contributes to the understanding of the conditions that are necessary for collaboration in such arrangements and the benefits that can be realized of such collaboration arrangements. This dissertation focuses on the vendor-buyer dyad in the supply chain. We identify and categorize collaboration arrangements that exist in practice, based on a review of the literature and combine this with formal analytical models in the literature. An important factor in the benefits of collaboration is the benefit of reduced costs of transport, by realization of economies of scale in the context of capacity-constrained trucks. As a contribution to the understanding of the dependence of transport costs on the volume transported, we demonstrate how transport tariffs for orders of less-than-a-truckload in size on a single link can be deduced from a basic model. The success of a collaboration arrangement depends on agreement about the distribution of decision authority and collaboration-benefits. We study a collaboration arrangement in which the vendor takes responsibility for managing the buyer's inventory and makes it economically attractive to the buyer by offering a financial incentive, dependent on the maximum level the buyer permits to be stocked. This dissertation demonstrates that this incentive alignment leads to considerable cost savings and near-optimal supply chain decisions. Verheijen, H.J.J. http://repub.eur.nl/res/pub/19551/ 2010-03-01T00:00:00Z A term map is a map that visualizes the structure of a scientific field by showing the relations between important terms in the field. The terms shown in a term map are usually selected manually with the help of domain experts. Manual term selection has the disadvantages of being subjective and labor-intensive. To overcome these disadvantages, we propose a methodology for automatic term identification and we use this methodology to select the terms to be included in a term map. To evaluate the proposed methodology, we use it to construct a term map of the field of operations research. The quality of the map is assessed by a number of operations research experts. It turns out that in general the proposed methodology performs quite well. Eck, N.J.P. van Waltman, L.R. Noyons, E.C.M. Buter, R.K.