René B.M. De Koster

René B.M. De Koster
Erasmus University Rotterdam | EUR · Rotterdam School of Management (RSM)

About

238
Publications
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10,543
Citations
Additional affiliations
September 1995 - present
Erasmus University Rotterdam
Position
  • Professor (Full)

Publications

Publications (238)
Article
Purpose In manual order picking systems, temporary workers are often employed to handle demand peaks. While this increases flexibility, it may hamper productivity, as they are usually unfamiliar with the processes and may have little experience. It is important for managers to understand how quickly inexperienced workers arrive at full productivity...
Article
Warehouses are becoming increasingly robotized. Autonomous rack-climbing robots have recently been introduced in e-commerce fulfillment centers. The robots not only retrieve loads from any level in a rack but also, roam the warehouse and bring the loads to order picking stations without using conveyors or lifts. This paper models and analyzes this...
Article
With the growth of ocean transport and with increasing vessel sizes, managing congestion at the landside of container terminals has become a major challenge. The landside of a sea terminal handles containers that arrive or depart via train or truck. Large sea terminals have to handle thousands of trucks and dozens of trains per day. As trains run o...
Preprint
Full-text available
Multi-tote storage and retrieval (MTSR) autonomous mobile robots (AMRs) can carry multiple product totes, store and retrieve them from different shelf-rack tiers, and transport the retrieved totes to a workstation where the products are picked to fulfill customer orders. In each robot trip, totes retrieved in the previous trip must be stored. This...
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An upward line extension is a new, improved product within an existing product category for the high-end market. Many manufacturers pursue line-extension strategies, but they carry risks due to uncertain consumer taste, the internal competition between products (represented by the firm's profitability for the line extension), and the external compe...
Article
At the core of every high-performing warehouse is an efficient order picking (OP) system. To attain such a system, policy choices should be carefully aligned with subjects responsible for the actual picking within the established system. Despite recent advancements in automating the picking process due to Industry 4.0, human operators will continue...
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Full-text available
Puzzle-based systems store unit loads in very high density without consuming space for transport aisles. In such systems, each load is stored on a moving device (conveyor module or transport vehicle), making these systems very expensive to build and maintain. This paper studies a new type of PBS system where loads are moved by a small number of aut...
Preprint
Full-text available
For nearly two decades, ocean carriers have been locked in an arms race for capacity, which has led to huge losses for many and even bankruptcy for some. We investigate the nature of this investment race by studying a long-term capacity investment problem in a duopoly under demand uncertainty. In our model, two firms make sequential capacity decisi...
Article
In the future, vehicle sharing platforms for passenger transport will be unmanned, autonomous, and electric. These platforms must decide which vehicle should pick up which type of customer based on the vehicle’s battery level and customer’s travel distance. We design dynamic vehicle allocation policies for matching appropriate vehicles to customers...
Article
Collaboration in warehousing has the potential to decrease warehousing costs and increase supply chain efficiency and is therefore popular in practice. However, there is little literature quantifying the benefits of warehouse collaboration. In this paper, we study the impact of collaboration on two main internal resources of the warehouse; order pi...
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The COVID-19 pandemic has caused global economic turmoil. Although many companies have suffered huge losses, some have flourished by changing their old ways of doing business. We investigate the business transformation process under drastic market changes and time pressure, with a focus on decision speed and structure in the decision & planning pha...
Article
This paper studies puzzle-based storage (PBS) systems with multiple simultaneously movable empty cells and with block movement (i.e. multiple loads in a line can move simultaneously). Simultaneous movement can potentially reduce the retrieval time substantially, but have not yet been rigorously studied. Our aim is to determine the minimum number of...
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Many distribution centers use expensive, conveyor-based sorting systems that require large buildings to house them. In areas with tight space, robotic sorting systems offer a new type of solution to sort parcels by destination. Such systems are highly flexible in throughput capacity and are now gradually being introduced, particularly in express co...
Preprint
Full-text available
The COVID-19 pandemic has caused global economic turmoil. Although many companies have suffered huge losses, some have flourished by changing their old ways of doing business. We investigate the business transformation process under drastic market changes and time pressure, with a focus on decision speed and structure in the decision & planning pha...
Article
Full-text available
Cross-efficiency measurement is an extension of Data Envelopment Analysis that allows for tie-breaking ranking of the Decision Making Units (DMUs) using all the peer evaluations. In this article we examine the theory of cross-efficiency measurement by comparing a selection of methods popular in the literature. These methods are applied to performan...
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Full-text available
In e-commerce fulfilment centres, storage assignment is critical to ensure short response times. To achieve this, many online retailers have moved to product dispersion in combination with product turnover-based slotting. However, commonly used policies do not fully utilise the historical customer demand information to optimise the storage assignme...
Article
A Robotic Mobile Fulfillment System (RMFS) is an automated parts-to-picker material handling system, in which robots carry pods with products to the order pickers. It is particularly suitable for e-commerce order fulfillment and can quickly and frequently reallocate workers and robots across the picking and replenishment processes to respond to str...
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Full-text available
Many operations are characterized by a trade-off between speed and quality. This calls for an exploration of effective strategies to balance the two metrics. This paper investigates the separate and joint effect of quantity and quality feedback on both performance metrics in order picking. We collected data from two real-effort experiments with in...
Article
The daily medicine delivery is one of the most important activities in hospitals. The traditional medicine delivery, from hospital warehouses to the patients, typically involves a human delivery team supplying patients by handcarts. The multiple steps in the medicine delivery process impact the efficiency and increase the risk of contamination. Man...
Article
Scheduling the availability of order pickers is crucial for effective operations in a distribution facility with manual order pickers. When order-picking activities can only be performed in specific time windows, it is essential to jointly solve the order picker shift scheduling problem and the order picker planning problem of assigning and sequenc...
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Full-text available
Order picking is one of the most demanding activities in many warehouses in terms of capital and labor. In parts-to-picker systems, automated vehicles or cranes bring the parts to a human picker. The storage assignment policy, the assignment of products to the storage locations, influences order picking efficiency. Commonly used storage assignment...
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Full-text available
Autonomous mobile robots (AMR) are currently being introduced in many intralogistics operations, like manufacturing, warehousing, cross-docks, terminals, and hospitals. Their advanced hardware and control software allow autonomous operations in dynamic environments. Compared to an automated guided vehicle (AGV) system in which a central unit takes...
Article
For over 10 years, container shipping lines have been locked in an arms race for capacity, which has led to huge losses for many carriers and even bankruptcy for some. We investigate the dynamics of this investment race by studying a long-term capacity investment problem in a competitive market under demand uncertainty. In our model, two firms make...
Article
Storage and retrieval automation has progressed rapidly. One such popular storage and retrieval system deploys two passing aisle-bound cranes. Each crane can access every location in the rack. To pass the other crane and prevent collision, each crane has to timely move the platform to an appropriate level and simultaneously rotate it. We develop a...
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Full-text available
Container terminals play an important role in the transportation of containerized goods in global supply chains. The number of containers handled in container terminals has increased astronomically. To accommodate and handle the increasing number of containers entering and leaving container terminals, their layout has seen several changes. New layo...
Article
Many intra-logistics systems, such as automated container terminals, distribution warehouses, and cross-docks, observe parallel process flows, which involve simultaneous (parallel) operations of independent resources while processing a job. When independent resources work simultaneously to process a common job, the effective service requirement of...
Article
We study a recently introduced smart compact automated parking system (CAPS), deploying straddle carriers, which require little footprint area. The straddle carriers can elevate and move a car over other cars in the horizontal direction in deep storage lanes, thereby considerably increasing the car storage capacity. Customers can reserve a parking...
Article
This editorial explores research opportunities of operations management due to special characteristics of online-to-offline ecommerce. Representative contributions collated in this special issue are summarized. Through these research efforts and achievements, we highlight challenges for future exploration.
Article
Warehouses are an inevitable component in any supply chain and a vividly investigated object of research. Much attention, however, is absorbed by warehousing systems dedicated to the special needs of online retailers in the business-to-consumer segment. Due to the ever increasing sales volumes of e-commerce this focus seems self-evident, but a much...
Article
The design of container terminal operations is complex because multiple factors affect operational performance. These factors include numerous choices for handling technology, terminal topology, and design parameters and stochastic interactions between the quayside, stackside, and vehicle transport processes. In this research, we propose new integr...
Article
Customer order response time and system throughput capacity are key performance measures in warehouses, which depend strongly on the storage strategies deployed. One popular strategy is to split inventory into a bulk storage and a pick stock, or forward-reserve (FR) storage. Managers often use a rule of thumb: when the ratio m of average picks per...
Preprint
Full-text available
Storage automation has progressed rapidly the last decades, also in hospitals and pharmacies. One such popular storage and retrieval system deploys two passing aisle-bound cranes. Each crane can access every location in the rack. To pass the other crane and prevent collision, each crane has to timely move the pick platform to an appropriate positio...
Preprint
Full-text available
Many cities struggle with space shortage for parking and transportation activities. We model and analyse a recently introduced smart compact automated parking system (CAPS), deploying straddle carriers, which require little footprint area. The straddle carriers can elevate and move a car over other cars in the horizontal direction in deep storage l...
Article
Robotic handling systems are increasingly applied in distribution centers. They require little space, provide flexibility in managing varying demand requirements, and are able to work 24/7. This makes them particularly fit for e-commerce operations. This paper reviews new categories of automated and robotic handling systems, such as shuttle-based s...
Article
This study illustrates the relevance and importance of incorporating safety constraints, picker blocking, and vertical travel due to high level storage locations when developing order picking systems (i.e., deciding on zoning, storage, batching, and routing). Results show that safety constraints induce wait times, and cause additional traveling, pi...
Article
We study the integrated problem of allocating containers and scheduling a yard crane in a block with multiple input/output (I/O) points. The crane moves each storage container from an I/O point to a location selected from a set of open locations. A location may be suitable to stack different containers. The crane moves retrieval containers from ret...
Article
Scheduling trucks and assigning them to dock doors are two major operational decisions at cross-dock facilities. Including flexibility by operating (part of)the dock doors in a mixed service mode is known to make cross-dock operations more efficient (i.e., when both inbound and outbound trucks can be processed at these mixed-mode doors). However, t...
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Full-text available
A Robotic Mobile Fulfillment System is a recently developed automated, parts-to-picker material handling system. Robots can move storage shelves, also known as inventory pods, between the storage area and the workstations and can continually reposition them during operations. This paper shows how to optimize three key decision variables: (1) the nu...
Article
The robotic mobile fulfillment system (MFS) is widely used for automating storage pick and pack activities in e-commerce distribution centers. In this system, the items are stored on movable storage shelves, also known as inventory pods, and brought to the order pick stations by robotic drive units. We develop stylized performance evaluation models...
Article
In many warehouses shuttle-based technologies have replaced the traditional AS/R system based storage technologies. The impact these systems have on downstream order picking performance is largely unknown. To study the interactions between upstream storage and downstream picking systems, we develop a novel analytical model for integrated storage an...
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Full-text available
Sequential zone picking systems are popular conveyor-based picker-to-parts order picking systems that divide the order picking area in work zones. When designing a zone picking system, it is important to know whether the throughput capability of the system can meet customer demand. However, the performance and maximum throughput capability of a zon...
Article
Many cities have implemented delivery time windows, which limit city center access for freight vehicles. Each city determines its time windows independently. However, time window restrictions of one city also affect store deliveries in neighbouring cities, since retailers combine deliveries to customers in different cities in a single trip. We deve...
Article
We investigate the impact of investments in delivery service with one or two major competing online retailers. Customers diffuse among the retailers, based on purchasing experience and online reviews (i.e., social network). Firms decide on investments aimed at maximizing profit. For both Nash and Stackelberg competition cases, the effect on market...
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Full-text available
Compact automated parking (CAP) systems are fully automated parking systems, which store cars densely. Such systems are mainly used in congested cities all over the world, providing rapid parking access and safe vehicle storage. We study a prominent new technology, with relatively low cost and rapid response. The system has a rotating ring equipped...
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Full-text available
E-commerce fulfillment competition evolves around cheap, speedy, and time-definite delivery. Milkrun order picking systems have proven to be very successful in providing handling speed for a large, but highly variable, number of orders. In this system, an order picker picks orders that arrive in real time during the picking process; by dynamically...
Article
E-commerce retailers face the challenge to assemble large numbers of time-critical picking orders each consisting of just a few order lines with low order quantities. Traditional picker-to-parts warehouses are often ill-suited for these prerequisites, so that automated warehousing systems (e.g., automated picking workstations, robots, and AGV-assis...
Article
More and more retailers allow customers to order goods online and then pick them up in a store. In this setting, these orders are typically served from a dedicated warehouse. This often means that the stores are visited by different vehicles to replenish the store inventory and to supply the pick-up points. Motivated by a collaboration with an omni...
Article
Robotic mobile fulfillment systems (RMFS) have seen many implementations in recent years, due to their high flexibility and low operational cost. Such a system stores goods in movable shelves and uses movable robots to transport the shelves. The robot is battery powered and the battery depletes during operations, which can seriously affect the perf...
Article
Warehouses deliver labor-intensive services to customers. Underperformance may result in high costs and unsatisfied customer demand. New market developments force warehouses to handle a large number of orders within tight time windows. To cope with this, order picking operations need to be optimized by solving a wide range of planning problems. Opt...
Article
In many service industries, customers have to wait for service. When customers have a choice, this waiting may influence their service experience, sojourn time, and ultimately spending, reneging, and return behavior. Not much is known however, about the system-wide impact of waiting on customer behavior and resulting revenue. In this paper, we empi...
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Full-text available
In traditional automated storage and retrieval (AS/R) systems, the storage and retrieval machine travels simultaneously in the horizontal and vertical directions. The so-called split-platform AS/R (or SP-AS/R) system consists of platforms (or shuttles and lifts) that can move independently in horizontal (shuttles) and vertical (lifts) directions. T...
Article
Full-text available
The Robotic Mobile Fulfillment Systems (RMFS) is a new type of robotized, parts-to-picker material handling system, designed especially for e-commerce warehouses. Robots bring movable shelves, called pods, to workstations where inventory is put on or removed from the pods. This paper simulates both the pick and replenishment process and studies the...
Article
Robotic compact storage and retrieval systems (RCSRS) have seen many implementations over the last few years. In such a system, the inventory items are stored in bins, organized in a grid. In each cell of the grid, a certain number of bins are stored on top of each other. Robots with transport and lifting capabilities move on the grid roof to trans...
Article
Semi-open queuing networks (SOQNs) are widely applied to measure performance of manufacturing, logistics, communications, restaurant, and health care systems. Many of these systems observe variability in the customer arrival rate. Therefore, solution methods, which are developed for SOQNs with time-homogeneous arrival rate, are insufficient to eval...
Article
Warehouse operations are vital for the success of a supply chain. This paper explores fit among warehouse management structure and the context in which the warehouse operates as an important driver of warehouse performance. Warehouse management structure has been operationalised as the extensiveness by which warehouse operations are planned and con...