Dissecting Drayage: An Examination of Structure, Information, and Control in Drayage Operations

The term dray dates back to the 14th century when it was used commonly to describe a type of very sturdy sideless cart . In the 1700s the word drayage came into use meaning “to transport by a sideless cart”. Today, drayage commonly refers to the transport of containerized cargo to and from port or rail terminals and inland locations. With the phenomenal growth of containerized freight since the container’s introduction in 1956, the drayage industry has also experienced significant growth. In fact, according to the Bureau for Transportation Statistics, the world saw total maritime container traffic grow to approximately 417 million twenty foot equivalent units (TEUs) in 2006. Unfortunately, the drayage portion of a door-to-door container move tends to be the most costly part of the move. There are a variety of reasons for this disproportionate assignment of costs, including a great deal of uncertainty at the interface of modes. For example, trucks moving containers to and from a port terminal are often uncertain as to how long it will take them to pick up a designated container coming from a ship, from the terminal stack, or from customs. This uncertainty leads to much difficulty and inefficiency in planning a profitable routing for multiple containers in one day. We study this problem from three perspectives using both empirical and theoretical techniques

A tabu search algorithm for scheduling a single robot in a job-shop environment

We consider a single-machine scheduling problem which arises as a subproblem in a job-shop environment where the jobs have to be transported between the machines by a single transport robot. The robot scheduling problem may be regarded as a generalization of the travelling-salesman problem with time windows, where additionally generalized precedence constraints have to be respected. The objective is to determine a sequence of all nodes and corresponding starting times in the given time windows in such a way that all generalized precedence relations are respected and the sum of all travelling and waiting times is minimized. We present a local search algorithm for this problem where an appropriate neighborhood structure is defined using problem-specific properties. In order to make the search process more efficient, we apply some techniques which accelerate the evaluation of the solutions in the proposed neighbourhood considerably. Computational results are presented for test data arising from job-shop instances with a single transport robot

An improved Ant Colony System for the Sequential Ordering Problem

It is not rare that the performance of one metaheuristic algorithm can be improved by incorporating ideas taken from another. In this article we present how Simulated Annealing (SA) can be used to improve the efficiency of the Ant Colony System (ACS) and Enhanced ACS when solving the Sequential Ordering Problem (SOP). Moreover, we show how the very same ideas can be applied to improve the convergence of a dedicated local search, i.e. the SOP-3-exchange algorithm. A statistical analysis of the proposed algorithms both in terms of finding suitable parameter values and the quality of the generated solutions is presented based on a series of computational experiments conducted on SOP instances from the well-known TSPLIB and SOPLIB2006 repositories. The proposed ACS-SA and EACS-SA algorithms often generate solutions of better quality than the ACS and EACS, respectively. Moreover, the EACS-SA algorithm combined with the proposed SOP-3-exchange-SA local search was able to find 10 new best solutions for the SOP instances from the SOPLIB2006 repository, thus improving the state-of-the-art results as known from the literature. Overall, the best known or improved solutions were found in 41 out of 48 cases.Comment: 30 pages, 8 tables, 11 figure

Models for intra-hospital patient routing

Diese Magisterarbeit befasst sich mit dem in-house Transport von Patienten in pavillonartig strukturierten Krankenhäusern. Dieses Thema hat in den letzten Jahren an Bedeutung gewonnen, da Routing in Krankenhäusern große Kosten verursacht und ein effizienteres Routing sowohl die Kosten senken, als auch die Servicequalität, gemessen an der Patientenzufriedenheit, erhöhen kann. Ziel dieser Arbeit ist es, ein neues Modell für das in-house Routing von Patienten in Krankenhäusern zu entwickeln, das die Ansprüche von Patienten und Management gleichermaßen erfüllt. Patienten in Krankenhäusern haben fixe Termine, wie z.B. Röntgen- oder Ultraschalluntersuchungen, und müssen aus medizinischen Gründen oft von Trägern zu diesen Terminen begleitet werden. Im Modell werden die logistischen Kosten der Verwendung von Trägern und die Unannehmlichkeiten von Patienten minimiert. Außerdem gibt es zwei Erweiterungen, in der Ersten stehen primär patientenorientierte Sachverhalte im Vordergrund, in der Zweiten stehen krankenhaus- bzw. managementorientierte Sachverhalte im Vordergrund. Es wird gezeigt, dass die entwickelten Modelle in der Lage sind, reale Problemstellungen in mittelgroßen Krankenhäusern zu lösen. Das Modell gehört zur Gruppe der Pickup and Delivery-Probleme. Unter bestimmten Umständen kann das Model auch als Dial-a-Ride-Problem oder als spezielle Variante eines Stacker-Crane-Problems gesehen werden.This thesis deals with the in-house transportation of the patients in pavilion structured hospitals. This topic has gained increased attention over the last years, due to the fact that routing operations come at a high price and that efficient routing plan could not only help reduce the costs, but also to improve the service quality, which is reflected through patients’ satisfaction. The aim of this work is to introduce a new model for intra-hospital routing of patients, considering both client- and management related issues. Patients in a hospital have fixed appointments, such as x-rays or ultrasonic and due to medical reasons they may not be able to walk on their own, so they have to be escorted by porters. In the model logistical costs for the usage of porters and patient inconvenience are minimized. Furthermore, the model is expanded and changed accordingly in order to capture distinguish patient centred issues on one hand and hospital centred issues on the other hand. It has been shown that the different developed model variants are tractable for realistic problem instances in medium-sized hospitals. The model belongs to the group of pickup and delivery problems. Under some circumstances, the problem can be also seen as a dial-a-ride problem, or a special type of a stacker-crane problem

An updated annotated bibliography on arc routing problems

The number of arc routing publications has increased significantly in the last decade. Such an increase justifies a second annotated bibliography, a sequel to Corberán and Prins (Networks 56 (2010), 50–69), discussing arc routing studies from 2010 onwards. These studies are grouped into three main sections: single vehicle problems, multiple vehicle problems and applications. Each main section catalogs problems according to their specifics. Section 2 is therefore composed of four subsections, namely: the Chinese Postman Problem, the Rural Postman Problem, the General Routing Problem (GRP) and Arc Routing Problems (ARPs) with profits. Section 3, devoted to the multiple vehicle case, begins with three subsections on the Capacitated Arc Routing Problem (CARP) and then delves into several variants of multiple ARPs, ending with GRPs and problems with profits. Section 4 is devoted to applications, including distribution and collection routes, outdoor activities, post-disaster operations, road cleaning and marking. As new applications emerge and existing applications continue to be used and adapted, the future of arc routing research looks promising.info:eu-repo/semantics/publishedVersio

Arc routing problems: A review of the past, present, and future

[EN] Arc routing problems (ARPs) are defined and introduced. Following a brief history of developments in this area of research, different types of ARPs are described that are currently relevant for study. In addition, particular features of ARPs that are important from a theoretical or practical point of view are discussed. A section on applications describes some of the changes that have occurred from early applications of ARP models to the present day and points the way to emerging topics for study. A final section provides information on libraries and instance repositories for ARPs. The review concludes with some perspectives on future research developments and opportunities for emerging applicationsThis research was supported by the Ministerio de Economia y Competitividad and Fondo Europeo de Desarrollo Regional, Grant/Award Number: PGC2018-099428-B-I00. The Research Council of Norway, Grant/Award Numbers: 246825/O70 (DynamITe), 263031/O70 (AXIOM).Corberán, Á.; Eglese, R.; Hasle, G.; Plana, I.; Sanchís Llopis, JM. (2021). Arc routing problems: A review of the past, present, and future. Networks. 77(1):88-115. https://doi.org/10.1002/net.21965S8811577

Modeling and optimal control of multiphysics problems using the finite element method

Interdisciplinary research like constrained optimization of partial differential equations (PDE) for trajectory planning or feedback algorithms is an important topic. Recent technologies in high performance computing and progressing research in modeling techniques have enabled the feasibility to investigate multiphysics systems in the context of optimization problems. In this thesis a conductive heat transfer example is developed and techniques from PDE constrained optimization are used to solve trajectory planning problems. In addition, a laboratory experiment is designed to test the algorithms on a real world application. Moreover, an extensive investigation on coupling techniques for equations arising in convective heat transfer is given to provide a basis for optimal control problems regarding heating ventilation and air conditioning systems. Furthermore a novel approach using a flatness-based method for optimal control is derived. This concept allows input and state constraints in trajectory planning problems for partial differential equations combined with an efficient computation. The stated method is also extended to a Model Predictive Control closed-loop formulation. For illustration purposes, all stated problems include numerical examples