Margaretha Gansterer

University of Vienna | UniWien · Faculty of Business, Economics and Statistics

Nowadays, industry and individuals alike are highly dependent on a reliable power supply. A large-scale power outage, commonly known as a “blackout” is caused by natural disasters, cyber attacks, technical failure, or human errors, and can lead to a variety of severe consequences. The far-reaching dynamics of blackouts can even result in the collap...

Attended home deliveries (AHDs) are characterized by dynamic customer acceptance and narrow customer‐specific delivery time windows. Both impede efficient routing and thus make AHDs very costly. In this article, we explore how established horizontal collaborative transportation planning methods can be adapted to render AHDs more efficient. The gene...

Hiking is among the most popular outdoor activities. In this paper, we introduce the hiking tourist problem (HTP) to support hikers in their trip planning to attractive hiking spots in a certain region. In the HTP, a set of hikes out of a larger set of potential hikes is selected and the mode of transport between the hiking locations is determined....

In this paper, we address the vehicle routing problem (VRP) with occasional drivers (ODs) and time windows (TWs). The problem (VRP-OD-TW) is an extension of the VRP-OD, where ODs serve customers within given TWs. Differently from the basic version of VRP-OD-TW, we assume that ODs not only accept single requests, but they can also serve bundles of r...

Cloud Manufacturing (CMfg) is a promising approach that leverages the sharing economy to reduce costs and enhance supply chain flexibility. Particularly, when utilised alongside Additive Manufacturing (AM), CMfg is considered a key enabler for collaborative production (CP) systems. However, there is still a lack of planning models that reduce entry...

As a major real‐world problem, snow plowing has been studied extensively. However, most studies focus on deterministic settings with little urgency yet enough time to plan. In contrast, we assume a severe snowstorm with little known data and little time to plan. We introduce a novel time‐dependent multi‐visit dynamic safe street snow plowing proble...

One of the main obstacles in horizontal collaborative transportation is the proper distribution of gains among partners. In practice, a posteriori gain sharing mechanisms rarely guarantee that all partners feel treated fairly. In this paper, we present the multi-depot vehicle routing problem with profit fairness (MDVRP-PF), a bi-objective optimizat...

One of the main obstacles in horizontal collaborative transportation is the proper distribution of gains among partners. In practice, a posteriori gain sharing mechanisms rarely guarantee that all partners feel treated fairly. In this paper, we present the multi-depot vehicle routing problem with profit fairness (MDVRP-PF), a bi-objective optimizat...

available open access at https://www.tandfonline.com/doi/full/10.1080/00207543.2022.2078249 Warehouses are key elements of supply chain networks, and great attention is paid to increase their efficiency. Highly volatile space requirements are enablers of innovative resource sharing concepts, where warehouse capacities are traded on online platform...

Traditionally, individuals and firms have bought and owned resources. For instance, owning a car was a status symbol for people. In recent years, this focus has changed. Young people just want to have some convenient means of transportation available. Sharing cars, bikes, or rides is also acceptable and has the advantage of increased sustainability...

Carriers can remarkably reduce transportation costs and emissions when they collaborate, for example through a platform. Such gains, however, have only been investigated for relatively small problem instances with low numbers of carriers. We develop auction-based methods for large-scale dynamic collaborative pickup and delivery problems, combining...

Safe and secure vehicle routing problems refer to the transportation of dangerous (e.g., flammable liquids) or valuable goods (e.g., cash), the surveillance of streets (e.g., police patrols) or other areas (e.g., those within a factory or building), and the response to sudden incidents (e.g., robberies or street disruptions). It thus covers a multi...

Additive Manufacturing (AM) is a technology with the potential to disrupt entire supply chains - one reason why AM attracted attention from both academia and practitioners in the last decade. In recent years, researchers have focused on increasing the efficiencies of AM operations as the technology has reached new levels of maturity. Collaborative...

Background Due to potentially immune-escaping virus variants and waning immunity, a third SARS-CoV-2 vaccination dose is increasingly recommended. However, data in patients with cancer are limited. Patients and methods We measured anti-SARS-CoV-2 spike protein antibody levels after the third vaccination dose in 439 patients with cancer and 41 heal...

In this paper, we introduce a new vehicle scheduling problem (VSP) with driver consistency faced by rental-with-driver companies. A weekly time-horizon is considered and a set of potential customers, each one associated with a list of required tasks, is assumed. The company can choose to accept or reject a customer, but if accepted, all required ta...

In this paper, we present the vehicle routing problem (VRP) with occasional drivers (OD) and order bundles (OB). The problem VRP-OD-OB is an extension of the VRP-OD, where instead of assigning one customer per driver, drivers are assigned bundles of customers. To deal with the bundle-to-driver assignment, a bidding system is exploited, in which a c...

Die meisten Konzepte für die kurz- und mittelfristige Planung basieren auf deterministischen Modellen.

Competitive markets, increased fuel costs, and underutilized vehicle fleets are characteristics that currently define the logistics sector. Given an increasing pressure to act in a manner that is economically and ecologically efficient, mechanisms that help to benefit from idle capacities are on the rise. In the Sharing Economy, collaborative usage...

In late 2019 a new coronavirus disease (COVID-19) emerged, causing a global pandemic within only a few weeks. A crucial factor in the public health response to pandemics is achieving a short turnaround time between a potential case becoming known, specimen collection and availability of a test result. In this article we address a logistics problem...

The rapid growth of e-commerce has led to an increase of home delivery requests. Providing efficient distribution systems for services on the last mile has become a challenging issue for logistics companies, where a trade-off between the classical approaches, attended home delivery (AHD) and usage of shared delivery locations (SDLs) has been identi...

Background During the second wave of the coronavirus disease 2019 (COVID-19) pandemic Austria suffered one of the highest severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rates worldwide. We report performance parameters of a SARS-CoV‑2 screening program established for cancer outpatients at our center. Methods Institutional policy rec...

Logistics providers have to utilize available capacities efficiently in order to cope with increasing competition and desired quality of service. One possibility to reduce idle capacity is to build coalitions with other players on the market. While the willingness to enter such coalitions does exist in the logistics industry, the success of collabo...

Cloud manufacturing is an emerging concept that enables the orchestration, matching, and sharing of services or resources among collaboration partners or intra-plant facilities. In this context, we introduce the capacitated multi-level lot sizing problem with transshipments and set up carry-over. We consider components that can only be produced by...

The rising competition in the logistics sector forces companies to be more economically efficient. One of the major sources of inefficiency is the incomplete usage of available resources, such as vehicles’ capacities. Mechanism that allow to better exploit such resources by enabling carrier collaborations are on the rise. Our study examines a centr...

Many security companies offer patrolling services, such that guards inspect facilities or streets on a regular basis. Patrolling routes should be cost efficient, but the inspection patterns should not be predictable for offenders. We introduce this setting as a multi‐objective periodic mixed capacitated general routing problem with objectives being...

While collaborative vehicle routing has a significant potential to reduce transportation costs and emissions, current approaches are limited in terms of applicability, unrealistic assumptions, and low scalability. Centralized planning generally assumes full information and full control, which is often unacceptable for individual carriers. Combinato...

PURPOSE To analyze the prevalence of SARS-CoV-2 infection in patients with cancer in hospital care after implementation of institutional and governmental safety measurements. METHODS Patients with cancer routinely tested for SARS-CoV-2 RNA by nasal swab and real-time polymerase chain reaction between March 21 and May 4, 2020, were included. The re...

The Traveling Salesman and Vehicle Routing Problems are integral parts of bachelor and master programs related to Operations Research/Management Science. This is due to their relevance in both practical applications and research. For students, it is essential to gain a deep understanding of the problems’ inherent complexity. For this, several tools...

Efficiency and security are the two major concerns in cash-in-transit transportation planning. Whereas efficiency is generally achieved by finding short routes, security can be improved by generating dissimilar visit patterns. To achieve a good balance between these two objectives, the vehicle routing problem with arrival time diversification (VRPA...

The logistics industry is known to suffer from inefficiencies. Recently published numbers on the percentage of trucks running idle or almost idle on European road networks are alarming. Collaborative transportation offers opportunities to share capacities and thus reduce inefficiencies and environmental pollution considerably. It is therefore a hig...

Given an increasing pressure to act economically and ecologically efficient, mechanisms to benefit from idle capacities are on the rise. In this “sharing economy”, carrier collaborations are a key concept. We assess the benefit of sharing information in auction-based carrier collaborations where carriers seek to exchange transportation requests in...

Collaborative operations planning is a key element of modern supply chains. We introduce the collaborative multi-level lot-sizing problem with cost synergies. This arises if producers can realise reductions of their costs by providing more than one product in a specific time horizon. Since producers are typically not willing to reveal critical info...

In collaborative logistics, carriers form coalitions in order to perform parts of their operational business jointly. Combinatorial auctions can be used to exchange transportation requests without having to reveal critical information. Collaborators submit requests for exchange to a common pool. The requests in the pool are then grouped into bundle...

Logistics networks are constantly evolving such that new and more varied structures arise and need to be studied. Carriers are aiming for opportunities to save costs by efficient planning. Motivated by this, we define the two-region multi-depot pickup and delivery problem. A region in this setting refers to an area where customers and depots are lo...

We assess the potential total profit in collaborative pickup and delivery problems, where carriers are willing to exchange transportation requests. For this, we design an adaptive large neighborhood search method that is used to generate solutions of publicly available but yet unsolved test instances. Our computational study reveals that collaborat...

In horizontal collaborations, carriers form coalitions in order to perform parts of their logistics operations jointly. By exchanging transportation requests among each other, they can operate more efficiently and in a more sustainable way. This exchange of requests can be organized through combinatorial auctions, where collaborators submit request...

In this study we investigate the decision problem of a central authority in pickup and delivery carrier collaborations. Customer requests are to be redistributed among participants, such that the total cost is minimized. We formulate the problem as multi-depot traveling salesman problem with pickups and deliveries. We apply three well-established e...

Collaboration has been one of the important trends in vehicle routing. A typical mechanism to enable carrier collaboration is to use combinatorial auctions, where requests are not traded individually but are combined into bundles. Previous literature on carrier collaboration has focused on issues such as bundle formation or winner determination, ty...

The rapid development experienced by the transportation industry in the past decades has led to many configurations of networks and therefore to an explosion of variants in transportation problems, motivating researchers to look at broader logistic problems, beyond the basic vehicle routing problems. This work introduces a new type of problem scena...

In this study, we consider balancing problems of one- and two-sided assembly lines with real-world constraints like task or machine incompatibilities. First, we study the one-sided assembly line balancing problem (ALBP) with a limited number of machine types per workstation. Using a genetic algorithm (GA), we find optimal results for real-world ins...

In horizontal collaborations, carriers form coalitions in order to perform parts of their logistics operations jointly. By exchanging transportation requests among each other, they can operate more efficiently and in a more sustainable way. Collaborative vehicle routing has been extensively discussed in the literature. We identify three major strea...

The transportation industry expanded rapidly in a highly competitive environment. Logistics companies with insufficient volume of transport capacities are forced to make a selection of customers that they can integrate efficiently into their tours. This is of particular relevance in the pickup and delivery market, where shipments from several diffe...

Tourism and travel with the purpose to do sports is gaining in popularity and the golf tourism market is considered to be one of the largest. Motivated by this phenomenon we model and solve the golf tourist problem which generalizes the orienteering problem with time windows. It aims at providing decision support for the traveling golfer by concurr...

In the highly competitive shipping and transportation industry, companies need to achieve a maximum level of efficiency in order to stay in business. To reach this goal they can, for instance, participate in collaborative networks and trade their transportation requests among each other. This is commonly done by using auction-based exchange systems...

Die meisten Konzepte für die kurz- und mittelfristige Planung basieren auf deterministischen Modellen. Somit wird bei der Planung unterstellt, dass schon zu Beginn der Planung alle Rahmenbedingungen und Parameter zumindest für den Zeitraum des Planungshorizonts bekannt sind. In der Praxis unterliegen fast alle Produktions- und Logistiksysteme unvor...

In hierarchical production planning (HPP) systems, aggregate production planning (APP) is meant to balance capacity requirements and production quantities for medium term planning horizons. Aggregate plans provide the basic input for further planning steps. In recent years researchers came up with comprehensive models and sophisticated solution met...

This paper presents the structure of a flexible discrete event simulation model for analyzing production systems. Based on BOM and routing information a simulation model is generated to analyze a shop floor structure. Different modules are used for generating customer orders and production orders and handling the material flow until the customer is...

Discrete-event simulation and (mixed-integer) linear programming are widely used for supply chain planning. We present a general framework to support the operational decisions for supply chain networks using a combination of an optimization model and discrete-event simulation. The simulation model includes nonlinear and stochastic elements, whereas...

Discrete-event simulation and (mixed-integer) linear programming are widely used for supply chain planning. We present a general framework to support the operational decisions for supply chain networks using a combination of an optimization model and discrete-event simulation. The simulation model includes nonlinear and stochastic elements, whereas...

In this paper we present a general framework for simulating and optimizing the operational decisions in a supply chain network. We developed a supply chain network library for the simulation software AnyLogic (copyXJ Technologies) and a linearized version as an optimization model implemented using XpressMP (copy Dash Optimization). Aggregated resul...

The main idea of our approach is to combine discrete-event simulation and exact optimization for supply chain network models. Simulation models are constructed in order to mimic a real system including all necessary stochastic and nonlinear elements. Such simulation models are used as proving grounds for analyzing and improving a real situation on...

In this paper we present a new approach to support the operational decisions for supply chain networks by combining LP modelling and discreteevent simulation. The network structure is assumed as given, but the transportation, production and inventory amounts are optimized. We develop an LP model of a general supply chain network including productio...