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This thesis concerns the integration of agent technology and mathematical optimization for improved decision support within the domain of analysis and planning of production and transportation. These two approaches have often been used separately in this domain but the research concerning how to combine them is very limited. The studied domain is considered to be complex due to the fact that many decision makers, which influence each other, often are involved in the decision making process. Moreover, problems in the domain are typically large and combinatorial, which makes them more difficult to solve. We argue that the integration of agent-based approaches and mathematical optimization has a high potential to improve analysis and planning of production and transportation. In order to support this hypothesis, we have developed and analyzed three different approaches to the integration of agent technology and mathematical optimization. First, we present a Multi-Agent-Based Simulation (MABS) model called TAPAS for simulation of decision-making and physical activities in supply chains. By using agent technology and optimization, we were able to simulate the decision-making of the involved actors as well as the interaction between them, which is difficult using traditional simulation techniques. In simulation experiments, TAPAS has been used to study the effects of different types of governmental taxes, and synchronization of timetables. Moreover, we provide an analysis of existing MABS applications with respect to a number of criteria. Also, we present a framework containing a number of abstract roles, responsibilities, and interactions, which can be used to simplify the process of developing MABS models. Second, we present an approach for efficient planning and execution of intermodal transports. The approach provides agent-based support for key tasks, such as, finding the optimal sequence of transport services (potentially provided by different transport operators) for a particular goods transport, and monitoring the execution of transports. We analyzed the requirements of such an approach and described a multi-agent system architecture meeting these requirements. Finally, an optimization model for a real world integrated production, inventory, and routing problem was developed. For solving and analyzing the problem, we developed an agent-based solution method based on the principles of Dantzig-Wolfe decomposition. The purpose was to improve resource utilization and to analyze the potential effects of introducing VMI (Vendor Managed Inventory). In a case study, we conducted simulation experiments, which indicated that an increased number of VMI customers may give a significant reduction of the total cost in the system.

In 1989 the late Prof Michael Beesley and Prof David Hensher convened a workshop of an invitational group of academics, transport operators and government regulators to review and report on the recent reforms in the British bus sector. The workshop was held in Thredbo, Australia. At the time this was a once off activity. Its success was such that it spawned a series of biannual conferences (now known as the Thredbo series) held in Finland (1991), Canada (1993), New Zealand (1995), England (1997), South Africa (1999), Norway (2001), Brasil (2003) and Portugal (2005). The conference series attracts a unique mix of researchers and practitioners with the common aim to share their experiences throughout the world on topics related to the institutional reform of land passenger transport (especially bus, rail and ferry). The focus is on workshops and plenary sessions in which participants are engaged in intense discussions that lead to the production of workshop reports that set the agenda for reform for the next period between the conferences. In the past workshop reports have been published in a major international journal and selected papers in special issues of journals.The growing number of citations of the material from the thredbo series has motivated this book, providing an opportunity to bring together in one volume the best papers from the conference plus the workshop reports. All chapters have been peer refereed. The themes in this volume (the first in a new series) include competition and regulation, contract specifications (especially performance-based contracts), regulatory and planning tools, institutional frameworks, service quality and pricing and performance data and measurement. Within one volume we provide a comprehensive update and review of the reform programs throughout the world in the land passenger transport sector. The volume is edited by Professor David Hensher, co-founder of the series and a recognized world authority in the field. It is the most current global assessment of reforms in land passenger transport. It contains papers written by those who influence policy and institutional reform in over 20 countries. It presents a comprehensive statement of the successes and failures in public transport reform. Many of the authors are regarded as the leading authorities in the field.The case studies throughout the world are not available in any other single source.

Maritime port efficiency is a research area that has received considerable attention in recent years. While the accumulated empirical evidence concerning the drivers of port efficiency is large, there has not been any attempt at systematically assessing the causes of (in)efficiency through quantitative meta-analysis. This study therefore uses a compounded dataset of port efficiency estimates from 52 studies and regresses these estimates on port and country characteristics, while controlling for study-specific and methodological effects. Surveying the literature, we find that there is a lack of attention paid to the user side of port service production, which has crucial implications for the interpretation of efficiency estimates. At the cross-country level, we find a negative relationship between GDP per capita and estimated port efficiency, as well as a negative relationship between intra-port competition and estimated efficiency. We discuss the interpretation of these findings in the context of partial production functions, and argue that a large portion of the applied methods do not capture substitution between producer and user inputs. We also find that the ratio of military spending to GDP is positively related to estimated port efficiency, while a higher degree of product concentration in trade flows is associated with lower levels of estimated efficiency

One of the official transport policy objectives in Sweden is that all citizens should have access to the transport system. The public sector is therefore required by law to provide special transport services (STS) for those who are unable to use public transport or private car. STS is often provided through public procurement of taxi services. As a response to new legislation in 2000, there have been developments in the public transport sector, making buses, trains and other parts of the system more accessible to people with disabilities. These developments have also been driven by other objectives, such as reducing costs in STS by transferring passengers from STS to regular public transport. However, so far, there is little evidence of the effects of public transport access on STS usage. The purpose of this paper is to study the effects of public transport system design on the demand for STS permits and usage. The main focus is on how different aspects of the general public transport system (e.g. price and supply levels) affect the demand for STS permits and STS usage per permit. In addition, the analysis will control for socioeconomic and geographical variables. It is concluded that the price and supply level of public transport do affect STS travel. Public transport price affects the demand for permits as well as the demand for trips from permit holders. Public transport service level only has an effect on the demand for permits.

AbstractUsing private contractors through procurement is common in most public sector areas. Despite the benefits of procurement, officials are sometimes tempted to circumvent procurement regulations. The aim of this article is to examine the strategies used by local governmental decisionmakers to bypass procurement regulations and to analyze the rationality underlying these officials' actions. Interviews, court documents, municipal documents, and newspaper articles describing the actions of Swedish municipal officials concerning special transport service (STS) procurements were collected and analyzed. In a case in which rural municipalities lost regular taxi services after STS procurement, we demonstrate how decisions were driven by pressure from the public and local interest groups, making municipal officials deviate from procurement regulations in striving to secure the existence of regular taxi services. One outcome was that local businesses were given preferential treatment, violating regulations and reducing economic efficiency.

Using private contractors through procurement is common in most public sector areas. Despite the benefits of procurement, officials are sometimes tempted to circumvent procurement regulations. The aim of the article is to examine strategies used by local governmental decision makers to bypass procurement regulations, analyzing the rationality underlying their actions. Interviews, court documents, municipal documents, and articles describing the actions of Swedish municipal officials concerning special transport service (STS) procurements were collected and analyzed. In a case in which rural municipalities lost regular taxi services after STS procurement, we demonstrate how decisions were driven by pressure from the public and local interest groups, making municipal officials deviate from procurement regulations in striving to secure the existence of regular taxi services. One outcome was that local businesses were given preferential treatment, violating regulations and reducing economic efficiency.

To predict which supply chain effects will appear when applying governmental control policies, infrastructure investments, and business strategies, multi-agent-based simulation (MABS) can be used. In this paper, we identify abstract supply chain responsibilities, roles and interactions that are argued to be sufficient for representing all types of organizations involved in the processes of buying and selling products and transport services. The identified responsibilities, roles and interactions are organized into a framework together witha set of modeling guidelines, which we relate to the GAIAmethodology to simplify the process of developing multi-agent-based supply chain simulation models. To illustrate the usage of the framework, we provide two case studies where we apply it to two different MABS models.

To predict which supply chain effects will appear when applying governmental control policies, infrastructure investments, and business strategies, multi-agent-based simulation (MABS) can be used. In this paper, we identify abstract supply chain responsibilities, roles and interactions that are argued to be sufficient for representing all types of organizations involved in the processes of buying and selling products and transport services. The identified responsibilities, roles and interactions are organized into a framework together with a set of modeling guidelines, which we relate to the GAIA methodology to simplify the process of developing multi-agent-based supply chain simulation models. To illustrate the usage of the framework, we provide two case studies where we apply it to two different MABS models.

An agent-based tool for micro-level simulation of transport chains (TAPAS) is described. It is more powerful than traditional approaches as it is able to capture the interactions between individual actors of a transport chain, as well as their heterogeneity and decision making processes. Whereas traditional approaches rely on assumed statistical correlation between different parameters, TAPAS relies on causality, i.e., the decisions and negotiations that lead to the transports being performed. An additional advantage is that TAPAS is able to capture time aspects, such as, the influence of timetables, arrival times, and time-differentiated taxes and fees. TAPAS is composed of two layers, one layer simulating the physical activities taking place in the transport chain, e.g., production, storage, and transports of goods, and another layer simulating the different actors' decision making processes and interaction. The decision layer is implemented as a multi-agent system using the JADE platform, where each agent corresponds to a particular actor. We demonstrate the use of TAPAS by investigating how the actors in a transport chain are expected to act when different types of governmental control policies are applied, such as, fuel taxes, road tolls, and vehicle taxes. By analyzing the costs and environmental effects, TAPAS provides guidance in decision making regarding such control policies. We argue that TAPAS may also complement existing approaches in different ways, for instance by generating input data such as transport demand. Since TAPAS models a larger part of the supply chain, the transport demand is a natural part of the output. Studies may concern operational decisions like choice of consignment size and frequency of deliveries, as well as strategic decisions like where to locate storages, terminals, etc., choice of producer, and adaptation of vehicle fleets.