Patrick Hirsch

Bio: Patrick Hirsch is an academic researcher from University of Natural Resources and Life Sciences, Vienna. The author has contributed to research in topics: Vehicle routing problem & Service provider. The author has an hindex of 18, co-authored 43 publications receiving 1109 citations.

Securing home health care in times of natural disasters

Abstract: The demand for home health care services is rising tremendously. It is important to maintain these services especially in times of natural disasters. Therefore, powerful algorithms are required to assist decision making. This paper presents a model formulation and solution approach for the daily planning of home health care services. In cooperation with the Austrian Red Cross, one of the leading providers of these services in Austria, we defined seven aims for the objective function. It minimizes the sum of driving times and waiting times, and the dissatisfaction levels of clients and nurses. A feasible solution has to observe assignment constraints, working time restrictions, time windows, and mandatory break times. The model formulation is implemented with the solver software Xpress 7.0 and solved for small problem instances. Real life-sized problems are tackled with a variable neighborhood search (VNS)-based heuristic that is capable of solving even large instances covering 512 jobs and 75 nurses. Extensive numerical studies with real life data from three districts in Upper Austria are presented. A sensitivity analysis shows how different natural disasters may influence home health care services. In 2002 a flood disaster devastated the studied areas. Data from this time and standard flood scenarios, namely the 30, 100, and 200 year return period flood discharges, are taken to depict the consequences on these services. Furthermore, a comparison of the heuristic solution values with an actual route plan shows extensive improvements.

A Branch-Price-and-Cut approach for solving the medium-term home health care planning problem

Abstract: The planning of home health care services is still done manually in many industrial countries. However, efficient decision support is necessary to improve the working plans and relieve the nurses from this time consuming task. The problem can be summarized as follows: clients need to be visited one or several times during the week by appropriately skilled nurses; their treatments have predefined time windows. Additionally, working time requirements for the nurses such as breaks, maximum working time per day, and daily as well as weekly rest times have to be considered. We propose a Branch-Price-and-Cut solution approach to solve this problem exactly, using the solutions of a variable neighborhood search solution approach as upper bounds. The algorithm is capable of solving to optimality real-life based test instances with up to nine nurses, 45 clients, and 203 visits during the week. © 2014 Wiley Periodicals, Inc. NETWORKS, Vol. 643, 143-159 2014

Daily scheduling of home health care services using time-dependent public transport

Abstract: This paper presents a real-world optimization problem in home health care that is solved on a daily basis. It can be described as follows: care staff members with different qualification levels have to visit certain clients at least once per day. Assignment constraints and hard time windows at the clients have to be observed. The staff members have a maximum working time and their workday can be separated into two shifts. A mandatory break that can also be partitioned needs to be scheduled if the consecutive working time exceeds a certain threshold. The objective is to minimize the total travel- and waiting times of the care staff. Additionally, factors influencing the satisfaction of the clients or the care staff are considered. Most of the care staff members from the Austrian Red Cross (ARC) in Vienna use a combination of public transport modes (bus, tram, train, and metro) and walking. We present a novel model formulation for this problem, followed by an efficient exact solution approach to compute the time-dependent travel times out of the timetables from public transport service providers on a minute-basis. These travel time matrices are then used as input for three Tabu Search based solution methods for the scheduling problem. Extensive numerical studies with real-world data from the ARC show that the current planning can be improved significantly when these methods are applied.

A survey on pickup and delivery problems: Part II: Transportation between pickup and delivery locations

Abstract: This paper is the second part of a comprehensive survey on pickup and delivery models. Basically, two problem classes can be distinguished. The first part dealt with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. In this class four subtypes were considered, namely the Vehicle Routing Problem with Clustered Backhauls (VRPCB all linehauls before backhauls), the Vehicle Routing Problem with Mixed linehauls and Backhauls (VRPMB any sequence of linehauls and backhauls permitted), the Vehicle Routing Problem with Divisible Delivery and Pickup (VRPDDP customers demanding delivery and pickup service can be visited twice), and the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP customers demanding both services have to be visited exactly once). The second part now considers all those problems where goods are transported between pickup and delivery locations, denoted as Vehicle Routing Problems with Pickups and Deliveries (VRPPD). These are the Pickup and Delivery VRP (PDVRP unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP paired pickup and delivery points), and the Dial-A-Ride Problem (DARP paired pickup and delivery points and user inconvenience taken into consideration). A single as well as a multi vehicle mathematical problem formulation for all three VRPPD types is given, and the respective exact, heuristic, and metaheuristic solution methods are discussed.

A survey on pickup and delivery problems

Abstract: This paper is the first part of a comprehensive survey on pickup and delivery problems. Basically, two problem classes can be distinguished. The first class, discussed in this paper, deals with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. This class is denoted as Vehicle Routing Problems with Backhauls (VRPB). Four subtypes can be considered, namely the Vehicle Routing Problem with Clustered Backhauls (VRPCB – all linehauls before backhauls), the Vehicle Routing Problem with Mixed linehauls and Backhauls (VRPMB – any sequence of linehauls and backhauls permitted), the Vehicle Routing Problem with Divisible Delivery and Pickup (VRPDDP – customers demanding delivery and pickup service can be visited twice), and the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP – customers demanding both services have to be visited exactly once). The second class, dealt with in the second part of this survey, refers to all those problems where goods are transported between pickup and delivery locations. These are the Pickup and Delivery Vehicle Routing Problem (PDVRP – unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP – paired pickup and delivery points), and the Dial-A-Ride Problem (DARP – passenger transportation between paired pickup and delivery points and user inconvenience taken into consideration). Single as well as multi vehicle versions of the mathematical problem formulations are given for all four VRPB types, the corresponding exact, heuristic, and metaheuristic solution methods are discussed.

Optimization approaches for civil applications of unmanned aerial vehicles (UAVs) or aerial drones: A survey

Abstract: Unmanned aerial vehicles (UAVs), or aerial drones, are an emerging technology with significant market potential. UAVs may lead to substantial cost savings in, for instance, monitoring of difficult-to-access infrastructure, spraying fields and performing surveillance in precision agriculture, as well as in deliveries of packages. In some applications, like disaster management, transport of medical supplies, or environmental monitoring, aerial drones may even help save lives. In this article, we provide a literature survey on optimization approaches to civil applications of UAVs. Our goal is to provide a fast point of entry into the topic for interested researchers and operations planning specialists. We describe the most promising aerial drone applications and outline characteristics of aerial drones relevant to operations planning. In this review of more than 200 articles, we provide insights into widespread and emerging modeling approaches. We conclude by suggesting promising directions for future research.

Taxonomic classification of planning decisions in health care: a structured review of the state of the art in OR/MS

Abstract: We provide a comprehensive overview of the typical decisions to be made in resource capacity planning and control in health care, and a structured review of relevant articles from the field of Operations Research and Management Sciences (OR/MS) 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 and OR/MS researchers with a method to identify, break down and classify planning and control decisions. Second, following the taxonomy, for six health care services, we provide an exhaustive specification of planning and control decisions in resource capacity planning and control. For each planning and control decision, we structurally review the key OR/MS articles and the OR/MS methods and techniques that are applied in the literature to support decision making.