Erwin W Hans

• Prof.dr.ir.
• Professor (Full) at University of Twente

Neonatology care, the care for premature and severely ill babies, is increasingly confronted with capacity challenges. The entire perinatal care chain, including the Neonatal Intensive Care Unit (NICU), operates at high occupation levels. This results in refusals, leading to undesirable transports to other centers or even abroad, which affects qual...

Volunteer responder systems (VRS) alert and guide nearby lay rescuers towards the location of an emergency. An application of such a system is to out-of-hospital cardiac arrests, where early cardiopulmonary resuscitation (CPR) and defibrillation with an automated external defibrillator (AED) are crucial for improving survival rates. However, many A...

Efficient Home Care (HC) provision is a challenging but relevant topic, as more and more care is moved from hospitals towards patients' homes. Typically, the HC provider gives the client the service to indicate their preference for a Time Window (TW), in which the HC nurse should arrive. However, the impact of this service on the operating costs of...

The significance of last-mile logistics in the healthcare supply chain is growing steadily, especially in pharmacies where the growing prevalence of medication delivery to patients' homes is remarkable. This paper proposes a novel mathematical model for the last-mile logistics of the pharmaceutical supply chain and optimizes a pharmacy's logistical...

Last-mile logistics in the healthcare supply chain is becoming increasingly important, especially in pharmacies where medication delivery to patients' homes is becoming prevalent. Therefore, this paper proposes a mathematical model for the last-mile logistics of the pharmaceutical supply chain and optimizes a pharmacy's logistical financial outcome...

Waiting time in healthcare is a significant problem that occurs across the world and often has catastrophic effects. There are various terms used for waiting time (“sojourn”, “throughput” etc.) and there is no consensus on how these terms are defined. Ambiguous definitions of waiting time make it difficult to compare and measure the problems relate...

Patient no-shows and cancellations are a significant problem to healthcare clinics, as they compromise a clinic's efficiency. Therefore, it is important to account for both no-shows and cancellations into the design of appointment systems. To provide additional empirical evidence on no-show and cancellation behaviour, we assess outpatient clinic da...

Background Every week, radiotherapy centers face the complex task of scheduling hundreds of treatment sessions amongst the available linear accelerators. With the increase in cancer patient numbers, manually creating a feasible and efficient schedule has shown to be a difficult, time-consuming task. Although operations research models have been inc...

This book presents healthcare logistics solutions that have been successfully implemented at a variety of healthcare facilities. In each case, a major challenge is presented, along with the solution approach and implementation steps, followed by the impact on hospital operations. Problems encountered when implementing the results in practice are al...

External-beam radiotherapy treatments are delivered by a linear accelerator (linac) in a series of high-energy radiation sessions over multiple days. With the increase in the incidence of cancer and the use of radiotherapy (RT), the problem of automatically scheduling RT sessions while satisfying patient preferences regarding the time of their appo...

Abstract Background In radiotherapy, minimizing the time between referral and start of treatment (waiting time) is important to possibly mitigate tumor growth and avoid psychological distress in cancer patients. Radiotherapy pre-treatment workflow is driven by the scheduling of the first irradiation session, which is usually set right after consult...

An admission lounge is an emerging type of hospital facility that potentially improves the efficiency and efficacy of the perioperative process. We propose a five-step approach for the design, suitability assessment, and optimisation of an admission lounge. The approach uses a case mix optimisation method to select patients for the admission lounge...

In external-beam radiotherapy (RT), high-energy radiation beams are delivered by a linear accelerator in a series of irradiation sessions undertaken over multiple days. In this work, we consider the problem of scheduling and sequencing RT sessions considering time window preferences given by patients for the starting time of their appointments. Mos...

Background: In radiotherapy, minimizing the time between referral and start of treatment (waiting time) is important to possibly mitigate tumor growth and avoid psychological distress in cancer patients. Radiotherapy pre-treatment workflow is driven by the scheduling of the first irradiation session, which is usually set right after consultation (...

Surgery groups are clustered surgery procedure types that share comparable characteristics (e.g. expected duration). Scheduling OR blocks leaves many options for operational surgery scheduling and this increases the variation in usage of both the OR and downstream beds. Therefore, we schedule surgery groups to reduce the options for operational sch...

The study of differences between timetabling research presented in conferences like PATAT or published in Annals of OR and commercial timetabling software used in Higher Education Institutions (HEIs) is essential for the discussion about innovation in both higher education and in commerce. In the field of planning and scheduling, a lot of developme...

This paper studies the suitability of classrooms for higher education. We propose a model to quantify the suitability, which allows measuring and optimizing the fit of classrooms for a given curriculum event. This model is unique, as there is no such model yet in literature that provides insight into the variables and interrelationships that are re...

Scheduling appointments in a multi-disciplinary clinic is complex, since coordination between disciplines is required. The design of a blueprint schedule for a multi-disciplinary clinic with open access requirements requires an integrated optimization approach, in which all appointment schedules are jointly optimized. As this currently is an open q...

Education logistics concerns the integral planning and control (P&C) of education related activities in education organizations, encompassing activities such as scheduling, facility management, staffing, performance management, curriculum development, and ICT management. It has a significant impact on the overall effectiveness and efficiency of the...

We address a stochastic operating room scheduling problem which consists of assigning an intervention date and operating room to surgeries on the waiting list, minimizing the under- and overtime costs of the operating rooms, and the cost of exceeding the capacity constraints of the system. Uncertainties in surgeries duration, in the arrivals of eme...

Histopathology laboratories aim to deliver high quality diagnoses based on patient tissue samples. Timely and high quality care are essential for delivering high quality diagnoses, for example in cancer diagnostics. However, challenges exist regarding employee workload and tardiness of results, which both impact the diagnostic quality. In this pape...

Inspired by the real life problem of a radiology department in a Dutch hospital, we study the problem of scheduling appointments, taking into account unscheduled arrivals and reprioritization. The radiology department offers CT diagnostics to both scheduled and unscheduled patients. Of these unscheduled patients, some must be seen immediately, whil...

As the number of people diagnosed with cancer increases, demand for radiotherapy (RT) services has been continuously growing. In RT, delays in the start of treatment have shown to increase the risk of tumor progression in various cancer types, and patients experience greater psychological distress when subject to longer waiting times. The RT proces...

Like many hospital departments, the gynecology department of the Jeroen Bosch Hospital experienced difficulties with scheduling outpatient appointments at the medically preferred times. Despite the time invested in creating the schedule, the compliance of the achieved schedules with the preferences of gynecologists is low, and the number of schedul...

Numerous benchmark sets exist for combinatorial optimization problems. However, in healthcare scheduling, only a few benchmark sets are known, mainly focused on nurse rostering. One of the most studied topics in the healthcare scheduling literature is surgery scheduling, for which there is no widely used benchmark set. An effective benchmark set sh...

Uncovering the selection criteria of HEIs when choosing timetabling applications, using ERP as a reference

Background The delivery of radiotherapy (RT) involves the use of rather expensive resources and multi-disciplinary staff. As the number of cancer patients receiving RT increases, timely delivery becomes increasingly difficult due to the complexities related to, among others, variable patient inflow, complex patient routing, and the joint planning o...

Background The delivery of radiotherapy (RT) involves the use of rather expensive resources and multi-disciplinary staff. As the number of cancer patients receiving RT increases, timely delivery becomes increasingly difficult due to the complexities related to, among others, variable patient inflow, complex patient routing, and the joint planning o...

Door integraal te plannen, verminderen pieken in werkdruk op verpleegafdelingen en gaat de kwaliteit van zorg omhoog. Op de afdeling Orthopedie van het St. Antonius Ziekenhuis Utrecht/Nieuwegein is dit gelukt dankzij een speciaal ontwikkelde systematiek.

Biografie Rudy Oude Vrielink is momenteel bezig met een promotieonderzoek aan de Universiteit Twente waarin onderzoek wordt gedaan naar het ontwerp van een sensor data infrastructuur en het gebruik van dynamische planningsalgoritmes, als onderdeel van het vakgebied onderwijslogistiek. Veel aandacht wordt besteed aan privacy en integriteit, aangezie...

Background Pathology departments face a growing volume of more and more complex testing in an era where healthcare costs tend to explode and short turnaround times (TATs) are expected. In contrast, the histopathology workforce tends to shrink, so histopathology employees experience high workload during their shifts. This points to the need for effi...

At the tactical planning level in a multi-project environment, uncertainties are inherent to the workloads, and costs may be involved for using non-regular capacity and violating project due dates. We propose an approach to identify whether non-regular capacities might be needed to meet the projects' due dates. This problem is known as rough-cut ca...

In the Netherlands, patients with an acute care demand after office hours often wrongly choose to visit the emergency department (ED), while they could have visited the general practitioners’ post (GPP). This may lead to overcrowding and increased costs. In this paper, we focus on an Integrated Emergency Post (IEP) at a Dutch hospital, where the ED...

In the Netherlands, patients with an acute care demand after office hours often wrongly choose to visit the emergency department (ED), while they could have visited the general practitioners’ post (GPP). This may lead to overcrowding and increased costs. In this paper, we focus on an Integrated Emergency Post (IEP) at a Dutch hospital, where the ED...

Tactical planning in hospitals involves elective patient admission planning and the allocation of hospital resource capacities. We propose a method to develop a tactical resource allocation and patient admission plan that takes stochastic elements into consideration, thereby providing robust plans. Our method is developed in an Approximate Dynamic...

Inaugural speech on the occasion of accepting the chair Operations Management in Healthcare, by prof.dr.ir. Erwin W. Hans

English translation of the inaugural lecture of prof.dr. Erwin W. Hans at the University of Twente

The block time (BT) schedule, which allocates Operating Rooms (ORs) to surgical specialties, causes inflexibility for scheduling outside the BT, which negatively affects new surgeons, new specialties, and specialties that have fluctuation in the number of surgeries. For this inflexibility, we introduce the concept of releasing ORs, and present a ge...

We consider a master surgery scheduling (MSS) problem in which block operating room (OR) time is assigned to different surgical specialties. While many MSS approaches in the literature consider only the impact of the MSS on operating theater and operating staff, we enlarge the scope to downstream resources, such as the intensive care unit (ICU) and...

This paper introduces a shift rostering problem that surprisingly has not been studied in literature: the weekend shift rostering problem. It is motivated by our experience that employees' shift preferences predominantly focus on the weekends, since many social activities happen during weekends. The Weekend Rostering Problem (WRP) addresses the ros...

We propose a mathematical programming formulation that incorporates annualized hours and shows to be very flexible with regard to modeling various contract types. The objective of our model is to minimize salary cost, thereby covering workforce demand, and using annualized hours. Our model is able to address various business questions regarding tac...

The design of container shipping networks is an important logistics problem, involving assets and operational costs measured in billions of dollars. To guide the optimal deployment of the ships, a single vessel round trip is considered by minimizing ...

This chapter studies the incorporation of uncertainty into multi-project rough-cut capacity planning. We use fuzzy sets to model uncertainties, adhering to the so-called possibilistic approach. We refer to the resulting proactive planning environment as Fuzzy Rough Cut Capacity Planning (FRCCP). Uncertain workloads are modeled as fuzzy numbers, and...

After surgery most of the surgical patients have to be admitted in a ward in the hospital. Due to financial reasons and a decreasing number of available nurses in the Netherlands over the years, it is important to reduce the bed usage as much as possible. One possible way to achieve this is to create an operating room (OR) schedule that spreads the...

Het sociale leven ? sportactiviteiten, verjaardagsbezoeken, het ontmoeten van vrienden ? vindt vooral in de weekeinden plaats. Dit maakt werken in het weekend voor veel mensen onaantrekkelijk. In sectoren waar de dienstverlening 7 dagen in de week en 24 uur per dag beschikbaar moet zijn, zoals in de gezondheidszorg en de beveiligingssector, dienen...

Tactical planning of resources in hospitals concerns elective patient admission planning and the intermediate term allocation of resource capacities. Its main objectives are to achieve equitable access for patients, to meet production targets/to serve the strategically agreed number of patients, and to use resources efficiently. This paper proposes...

SAMENVATTING In April 2010 is de Centrale Huisartsenpost Almelo (HAP) geïntegreerd met de spoedeisende hulpafdeling (SEH) van Ziekenhuisgroep Twente (ZGT) Almelo in één spoedpost. De Universiteit Twente (UT) heeft samen met de spoedpost onderzocht hoe deze optimaal ingericht kan worden zodat een patiënt zonder onnodige vertraging met een optimale...

Planning and scheduling of health care processes has improved considerably using operations research techniques. Besides analytical and optimization tools, a substantial amount of sophisticated discrete event simulation tools supporting (re-)design of existing logistical processes in and around hospitals has been developed. Surprisingly, these stud...

This series of discussions presents commentaries on where the field of healthcare operations management is now and possible future research directions, expanding upon the key points raised by Green [Green LV (2012) The vital role of operations analysis in improving healthcare delivery. Manufacturing Service Oper. Management 14(4):488–494].

After surgery most of the surgical patients have to be admitted in a ward in the hospital. Due to financial reasons and an decreasing number of available nurses in the Netherlands over the years, it is important to reduce the bed usage as much as possible. One possible way to achieve this is to create an operating room (OR) schedule that spreads th...

Hospitals aim to deliver the highest quality of care. One key priority is to schedule emergency surgeries as quickly as possible, because postponing them generally increases a patient?s risk of complications. In this paper, we consider the case that emergency surgeries are scheduled in one of the elective Operating Rooms (ORs). In this situation, e...

Daily traffic congestions form major problems for businesses such as logistical service providers and distribution firms. They cause late arrivals at customers and additional hiring costs for the truck drivers. The additional costs of traffic congestions can be reduced by taking into account and avoid well-predictable traffic congestions within off...

To examine the use of computer simulation to reduce the time between the CT request and the consult in which the CT report is discussed (diagnostic track) while restricting idle time and overtime. After a pre implementation analysis in our case study hospital, by computer simulation three scenarios were evaluated on access time, overtime and idle t...

Outpatient clinics traditionally organize processes such that the doctor remains in a consultation room while patients visit for consultation, we call this the Patient-to-Doctor policy (PtD-policy). A different approach is the Doctor-to-Patient policy (DtP-policy), whereby the doctor travels between multiple consultation rooms, in which patients pr...

Health care planners in countries with a system based on a National Health Service (NHS) have to make decisions on where to locate and how to organize hospital services, so as to improve the geographic equity of access in the delivery of care while accounting ...

Rising expenditures spur healthcare organizations to organize their processes more efficiently and effectively. Unfortunately, healthcare planning and control lags behind manufacturing planning and control. We analyze existing planning and control concepts or frameworks for healthcare operations management and find that they do not address various...

In this chapter we present a number of approaches to operating theatre planning and scheduling. We organize these approaches hierarchically which serves to illustrate the breadth of problems confronted by researchers. At each hierarchicalplanning level we describe common problems, solution approaches and results from studies at partner hospitals.

Zorgvuldige afstemming tussen het schema van de operatiekamers en de verpleegafdeling balanceert de belasting van de verpleegafdeling en vermindert het aantal afgezegde operaties. In samenwerking tussen het Center for Healthcare Operations Improvement & Research (CHOIR, kenniscentrum voor optimalisatie van zorgprocessen en onderzoek in Nederland va...

This paper introduces a shift rostering problem that surprisingly has not been studied in literature: the weekend shift rostering problem. It is motivated by our experience that employees? shift preferences predominantly focus on the weekends, since many social activities happen during weekends. The Weekend Rostering Problem (WRP) addresses the ros...

We present a methodology to design appointment systems for outpatient clinics and diagnostic facilities that offer both walk-in and scheduled service. The developed blueprint for the appointment schedule prescribes the number of appointments to plan per day and the moment on the day to schedule the appointments. The method consists of two models th...

Purpose: Breast cancer occurs in about one in nine women in the Netherlands. Every year, 11,000 new cases are registered and about 3,500 women die of breast cancer. Prognosis after primary treatment is improving, leading to an increased number of follow-up visits and increasing workload to physicians. National guidelines currently assign all these...

No other department influences the workload of a hospital more than the Department of Surgery and in particular, the activities in the operating room. These activities are governed by the master surgical schedule (MSS), which states which patient types receive surgery on which day. In this paper, we describe an analytical approach to project the wo...

Inspired by a helicopter maintenance planning problem, we study the integration of uncertainties into tactical multi-resource, multi-project planning (Rough Cut Capacity Planning). We model uncertainty by a fuzzy/possibilistic approach instead of a stochastic approach to be able to develop robust plans in situations where very limited data is avail...

We introduce the categorized reference database ORchestra, which is available online at http://www.utwente.nl/choir/orchestra/.

For the intensively studied vehicle routing problem (VRP), two real-life restrictions have received only minor attention in the VRP-literature: traffic congestion and driving hours regulations. Traffic congestion causes late arrivals at customers and long travel times resulting in large transport costs. To account for traffic congestion, time-depen...

As the demand for health care services increases, the need to improve patient flow between departments has likewise increased. Understanding how the master surgical schedule (MSS) affects the inpatient wards and exploiting this relationship can lead to a decrease in surgery cancellations, a more balanced workload, and an improvement in resource uti...

Most solution methods for the vehicle routing problem with time windows (VRPTW) develop routes from the earliest feasible departure time. In practice, however, temporary traffic congestion make such solutions non-optimal with respect to minimizing the total duty time. Furthermore, the VRPTW does not account for driving hours regulations, which rest...

In this paper we address the decision of choosing a patient mix for a hospital that leads to the most beneficial treatment case mix. We illustrate how capacity, case mix and patient mix decisions are interrelated and how understanding this complex relationship is crucial for achieving the maximum benefit from the fee-for-service financing system. A...

We provide a structured overview of the typical decisions to be made in resource capacity planning and control in health care, and a review of relevant OR/MS articles for each planning decision. The contribution of this paper is twofold. First, to position the planning decisions, a taxonomy is presented. This taxonomy provides health care managers...

Rising expenditures spur health care organizations to organize their processes more efficiently and effectively. Unfortunately, health care planning and control lags far behind manufacturing planning and control. Successful manufacturing planning and control concepts can not be directly copied, because of the unique nature of health care delivery....

Operating room (OR) planning and scheduling is a popular and challenging subject within the operational research applied to health services research (ORAHS). However, the impact in practice is very limited. The organization and culture of a hospital and the inherent characteristics of its processes impose specific implementation issues that affect...

We describe a real world case study that involves the monthly planning and scheduling of the sand-casting department in a metal foundry. The problem can be characterised as a single-level multi-item capacitated lot-sizing model with a variety of additional process-specific constraints. The main objective is to smooth production. We present a hierar...

For the intensively studied vehicle routing problem (VRP), two real-life restrictions have received only minor attention in the VRP-literature: traffic congestion and driving hours regulations. Traffic congestion causes late arrivals at customers and long travel times resulting in large transport costs. To account for traffic congestion, time-depen...